大野 伸彦

A case of extraskeletal myxoid chondrosarcoma (ESMC), which developed in the right thigh of a middle-aged Japanese woman, was studied using immunohistochemistry, conventional electron microscopy, and the quick-freezing and deep-etching (QF-DE) method. In addition to typical light microscopic findings of ESMC, conventional electron microscopy indicated that the tumor cells had features of chondrocytes. Immunohistochemically, the tumor cells showed a positive immunoreaction for S100 protein. A diagnosis of ESMC was made. An interesting observation was the ultrastructural features of collagen fibrils in the myxoid matrix highlighted by the QF-DE method. These collagen fibrils consisted of relatively thin collagen (20-35 nm) with pleated surface structures. The surface striation at 65 nm was obscure. We consider that such a finding of collagen fibrils identified by the QF-DE method is one of the characteristics of the myxoid matrix of ESMC, and this is useful for the differential diagnosis of myxoid soft tissue tumors.

Umbrella cells (UCs) of the epithelium of the urinary bladder have the capacity to control bladder volume by regulating exocytosis/endocytosis of their intracellular discoid vesicles (DVs). Dynamin (Dyn) is a GTPase that promotes endocytic processes through scission of cell membranes. We have examined whether Dyn2, the most abundant Dyn form, is expressed in UCs and contributes to their endocytic actions. A specific antibody against Dyn2 was used to localize Dyn2 in human and rodent UCs by immunohistochemistry. To clarify the functional roles of Dyn2, mouse bladders were treated with a Dyn-GTPase inhibitor, dynasore, and its effects on their UC structure were assessed. Since uropathogenic Escherichia coli can be encased into UCs during infection, we used immunohistochemistry to determine whether bacteria-encasing compartments in the infected UCs were also enriched with Dyn2. Light microscopy showed that Dyn2 was abundantly expressed in UCs, especially near the apical cytoplasmic regions. By immunoelectron microscopy, Dyn2 was found on and around DV membranes in UCs. Ultrastructural analysis with a quick- freezing and deep-etching method confirmed these findings and revealed the existence of distinct Dyn2-bound microfilaments in close association with DV membranes. Dynasore treatment of bladders markedly reduced the number of DVs in UCs. In infected UCs, E. coli was encased in compartments enriched in Dyn2. Therefore, Dyn2 is highly enriched in UCs and mostly associated with membranes of DVs and microfilaments in the UCs. Pretreatment of bladders with dynasore inhibits E. coli invasion of UCs. Dyn2 thus contributes to the structural integrity of DVs and to the endocytic activity of UCs.

Protein kinases (PKs) phosphorylate proteins at active regions for signal transduction. In this study, normal and hypoxic mouse kidneys were prepared using an "in vivo cryotechnique" (IVCT) and examined immunohistochemically with specific antibodies against phospho-(Ser/Thr) PKA/C substrate (P-PK-S) and phospho-(Ser/Thr) Akt substrate (P-Akt-S) to capture their time-dependent regulation in vivo. Left kidneys were cryofixed with IVCT under normal blood circulation and after varying hypoxic intervals, followed by freeze-substitution with acetone containing paraformaldehyde. Deparaffinized sections were immunostained for P-PK-S, Na+/HCO3 (-) cotransporter NBC1, and a membrane skeletal protein, 4.1B. The P-PK-S was diffusely immunolocalized in the cytoplasm of the proximal tubules in normal kidneys, whereas NBC1 and 4.1B were detected at the basal striations of S1 and S2 segments of the proximal tubule. After 10 or 30 s hypoxia, P-PK-S was still immunolocalized in the cytoplasm of kidneys, but it was detected at the basal striations after 1 or 2 min hypoxia. The immunolocalization of P-Akt-S was the same as P-PK-S in the normal and hypoxic kidneys. Immunoblotting analyses of the kidney tissues under normal or hypoxic condition clearly identified the same 40-kDa bands. The IVCT is useful for time-dependent analysis of the immunodistribution of P-PK-S and P-Akt-S.

Protein 4.1B is a membrane skeletal protein expressed in various organs, and is associated with tumor suppressor in lung cancer-1 (TSLC1) in vitro. Although involvement of 4.1B in the intercellular junctions and tumor-suppression was suggested, some controversial results posed questions to the general tumor-suppressive function of 4.1B and its relation to TSLC1 in vivo. In this study, the expression of 4.1B and its interaction with TSLC1 were examined in rodent adrenal gland, and the involvement of 4.1B in tumorigenesis and the effect of 4.1B deficiency on TSLC1 distribution were also investigated using rodent pheochromocytoma and 4.1B-knockout mice. Although plasmalemmal immunolocalization of 4.1B was shown in chromaffin cells of rodent adrenal medulla, expression of 4.1B was maintained in developed pheochromocytoma, and morphological abnormality or pheochromocytoma generation could not be found in 4.1B-deficient mice. Furthermore, molecular interaction and colocalization of 4.1B and TSLC1 were observed in mouse adrenal gland, but the immunolocalization of TSLC1 along chromaffin cell membranes was not affected in the 4.1B-deficient mice. These results suggest that the function of 4.1B as tumor suppressor might significantly differ among organs and species, and that plasmalemmal retention of TSLC1 would be maintained by molecules other than 4.1B interacting in rodent chromaffin cells. (c) 2009 Elsevier B.V. All rights reserved.

Despite the potential association of polycystic ovary (PCO) syndrome with hemodynamic changes, follicular microenvironment and the involvement of blood follicle barriers (BFB), a histopathological examination has been hampered by artifacts caused by conventional preparation methods. in this study, mouse ovaries of a mifepristone-induced PCO model were morphologically and immunohistochemically examined by in vivo cryotechnique (IVCT), which prevents those technical artifacts. Ovarian specimens of PCO model mice were prepared by IVCT or the conventional perfusion fixation after s.c. injection of mifepristone. Their histology and immunolocalization of plasma proteins, including albumin (molecular mass, 69 kDa), immunoglobulin G (IgG, 150 kDa), inter-alpha-trypsin inhibitor (ITI, 220 kDa), fibrinogen (340 kDa), and IgM (900 kDa), were examined. In the PCO model, enlarged blood vessels with abundant blood flow were observed in addition to cystic follicles with degenerative membrana granulosa. The immunolocalization of albumin and IgM in the PCO model were similar to those in normal mice. Albumin immunolocalized in the blood vessels, interstitium or follicles, and IgM was mostly restricted within the blood vessels. In contrast, immunolocalization of IgG, ITI, and fibrinogen changed in the PCO model. Both IgG and ITI were clearly blocked by follicular basement membranes, and hardly observed in the membrana granulosa, though fibrinogen was mostly observed within blood vessels. These findings suggest that increased blood flow and enhanced selectivity of molecular permeation through the BFB are prominent features in the PCO ovaries, and changes in hemodynamic conditions and permselectivity of BFB are involved in the pathogenesis and pathophysiology of PCO syndrome.

BACKGROUND. Assessment of tissue specimens obtained with common immersion-fixation followed by dehydration (IMDH) is affected by artifacts, which hinder precise evaluation of the histology and microenvironment of tumor tissues. The technical characteristics of cryobiopsy and in vivo cryotechnique (IVCT) where target organs are directly cryofixed in vivo are still unknown in practical examinations of tumor histopathology and microenvironment. METHODS. Three lines of human lung cancer cells were subcutaneously injected to the dorsal flank of nude mice, and paraffin sections and cryosections of produced tumors were prepared with cryobiopsy, IVCT, the quick-freezing of the fresh resected tumor tissues, or IMDH. Histological comparison among different methods was conducted, and immunolocalization of immunoglobulin M (IgM), intravenously injected bovine serum albumin (BSA), and vascular endothelial growth factor (VEGF) were examined. RESULTS. With both the cryobiopsy and IVCT, cellular morphology and open blood vessels with flowing erythrocytes could be observed without artificial shrinkage, and the volume of blood vessels was not affected by a vascular collapse, which was observed after tissue-resection. In addition, with cryobiopsy and IVCT, IgM was well preserved in functional vessels with blood flow, which could be observed with injected BSA, and the volume of IgM-immunopositive blood vessels was significantly associated with the expression of VEGF. CONCLUSIONS. Cryobiopsy Could be useful for histological examination of human tumors without morphological artifacts associated with IMDH. Furthermore, it allows direct examination of functional blood vessels and related signaling molecules, thereby providing a better evaluation of the human tumor microenvironment for clinical application.

To measure oxygen saturation (SO(2)) of flowing erythrocytes in blood vessels of living animals, our "in vivo cryotechnique" (IVCT) was combined with confocal Raman microscopy at low temperature (- 150 degrees C), referred to as cryomicroscopy. We evaluated two resonance Raman (RR) shifts around 1355 and 1378 cm(-1), reflecting de-oxygenated and oxygenated hemoglobin molecular structures, respectively. judging from the calibration analyses of quickly frozen human whole blood for the control experiment in vitro, the two RR shifts were well retained at the low temperature, and their calculated ratios mostly reflected the relative SO(2) measured with a blood-gas analyzer. In blood vessels of living mouse organs prepared with the IVCT, their RR spectral peaks were also detected at the same RR shifts obtained in human blood. In the blood vessels of living mouse small intestines, some arterioles and venules were clearly distinguishable by monitoring different peak patterns of their RR shifts. The different ratios of the RR shift-areas were calculated even in the arterial vessels. In blood vessels of mouse livers, the Raman spectra showed a lower peak shift of 1378 cm(-1) compared to that of 1355 cm(-1), indicating an SO(2) decrease in hepatic blood circulation. Thus, the new cryopreparation technique will enable us to directly analyze the in Vivo SO(2) in various tissues of a whole animal body prepared with the IVCT, reflecting their living states. (c) 2008 Elsevier Inc. All rights reserved.

To identify immunoglobulin (Ig)-producing cells with immunohistochemistry, conventional methods of preparation using chemical fixatives have problems such as the artificial diffusion of components and antigen masking. The "diffusion artifact" is caused by the translocation of soluble proteins like Ig from the serum to cytoplasm or vice versa. We have examined the immunolocalization of serum proteins, such as Ig kappa light chain (Ig kappa), IgG1 heavy chain (IgG1), and albumin, in immunized mouse spleens after a peritoneal injection of human hemoglobin. Better preservation of morphology and immunoreactivity was obtained with the "in vivo cryotechnique" (IVCT) followed by freeze-substitution, than with conventional preparative methods. Although Ig-producing cells were not clearly detected in red pulp of 2-day-immunized spleens with the conventional methods, Ig kappa-immunopositive cells with rich cytoplasm were detected in the red pulp with IVCT, especially in the subcapsular and peritrabecular areas, where IgG1-immunopositive cells were rarely observed. In 7-day-inummized spleens prepared with IVCT, Ig kappa- or IgG1-immunopositive cells were mostly located in peritrabeculae. The development of Ig-producing cells was clarified in the specimens prepared with IVCT, which proved to be useful for analyzing the native morphology and distribution of Ig-producing cells. (C) 2008 Elsevier B.V. All rights reserved.

Our recent studies demonstrated the localization of protein 4.1 B, a member of the 4.1 skeletal membrane proteins, to the basolateral membranes of the S1-S2 renal proximal tubules. In the present studies, we investigated the presence of binding partners that could form a molecular complex with the 4.1 B protein. Immunohistochemistry revealed the localization of p55, a membrane-associated guanylate kinase, and the sodium bicarbonate cotransporter1 (NBC1), to the basolateral membrane domain of S1-S2 in mouse renal proximal tubules. Using immunoprecipitation of kidney lysates with anti-p55 antibody, a positive band was blotted with anti-4.1 B antibody. GST fusion proteins including the NBC1 and 4.1 B regions were confirmed to bind with each other by electrophoresis after mixing. Both NBC1- and 4.1B-specific bands were detected in renal protein mixtures immunoprecipated by either anti-4.1B- or NBC1-specific antibodies. It is likely that NBC1,4.1B, and p55 form a molecular complex in the basolateral membrane of the kidney S1-S2 proximal tubules. We propose that the 4.1B-containing membrane skeleton may play a role in regulating the Na+ and HCO3- reabsorption in S1-S2 proximal tubules.

Conventional methods of preparing tissue specimens for morphological investigation of the central nervous system suffer from inevitable artifacts caused by anoxia during the processing. In the present study we performed ultrastructural analyses of mouse cerebellar cortex using the in vivo cryotechnique (IVCr), which minimizes ischemic artifacts of target organs through direct cryofixation in vivo. In molecular and Purkinje cell layers of the mouse cerebellum prepared with IVCr, considerably large extracellular spaces (ECS) were detected among cellular profiles and synaptic clefts. The ECS obtained with IVCr without ischemia were larger than those obtained with IVCr after 8-minute ischemia or a conventional quick-freezing method with fresh resected tissues (FQF), but did not decrease with IVCr after 30-second ischernia. By contrast, the parallel fibers observed with IVCr without ischernia were slightly smaller than those after 30-second ischemia, and significantly smaller than those prepared with IVCr after 8-minute ischernia or FQF. ECS were frequently preserved around synaptic clefts, although the rest were totally or partially enclosed with closely apposed glial processes. The estimated sizes of the ECS around synaptic clefts did not differ between the opened and enclosed synapses, suggesting that the opened synapses might be temporarily surrounded by glial sheaths dynamically extending or retracting throughout the perisynaptic ECS. These findings indicate IVCr to be useful for some morphological analyses of ECS in the central nervous system. The appreciable ECS around synapses would allow morphological and functional changes of neuronal and glial cells dynamically involved in synaptic remodeling or signal transduction.

To evaluate hypoxic cells in live mouse liver tissues, immunohistochemistry for protein adducts of reductively activated pimonidazole (PARaPi) was performed using the "in vivo cryotechnique (IVCT)" followed by freeze-substitution fixation. This method was used because cryotechniques have some merits for examining biological events in living animal organs with improved time-resolution compared to conventional perfusion and/or immersion chemical fixation. Pimonidazole was intraperitoneally injected into living mice, and then after various times of hypoxia, their livers were quickly frozen by IVCT. The frozen liver tissues were freeze-substituted in acetone containing 2% paraformaldehyde, and routinely embedded in paraffin wax. De-paraffinized sections were immunostained for PARaPi. In liver tissues of mice without hypoxia, almost no immunostained cells were detected. However, in liver tissues with 30 s of hypoxia, some hepatocytes in the pericentral zones were strongly immunostained. After 60 s of hypoxia, many hepatocytes were immunostained with various degrees of staining intensity in all lobular zones, indicating different reactivities of pimonidazole in the hepatocytes to hypoxia. At this time, the general immunoreactivity also appeared to be stronger around the central veins than other portal areas. Although many hepatocytes were immunostained for PARaPi in the liver tissues with perfusion fixation via heart, those with perfusion via portal vein were not immunostained. Thus, IVCT is useful to detect time-dependent hypoxic states with pimonidazole treatment in living animal organs.

The molecular sieve with size- and charge selectivity in ovarian follicles, the so-called blood-follicle barrier (BFB), was examined during follicular development under physiological conditions to reveal ovarian structures responsible for the BFB by using our 'in vivo cryotechnique' (IVCT). Mouse ovary specimens were prepared with different methods including lVCT, immersion, or perfusion chemical fixation and quick-freezing following resection or perfusion. Their paraffin sections or cryosections were stained with hematoxylin-eosin or immunostained for serum proteins with different molecular weights: albumin, immunoglobulin (Ig) G1 heavy chain, inter-alpha-trypsin inhibitor (I alpha I), fibrinogen, and IgM. Their immunoreactivity was better preserved with IVCT. The immunostaining for albumin was clearly observed in blood vessels, interstitium, and developing follicles, but that of IgGI, I alpha I, or fibrinogen was significantly decreased inside the follicles. IgM was immunohistochernically decreased throughout the interstitium outside blood vessels. The immunoreactivities of IgG1 and IgM, as compared with albumin, were clearly changed along follicular basement membranes and around vascular endothelial cells respectively. These findings indicate that BFB functions throughout follicular development, and the follicular basement membrane and the vascular endothelium could play some significant roles in the permselectivity for such soluble proteins with intermediate and high molecular weight respectively.

The wavelength of Raman-scattered light depends on the molecular composition of the substance. This is the first attempt to acquire Raman spectra of a mouse eyeball removed from a living mouse, in which the eyeball was preserved using the "in vivo cryotechnique" followed by freeze-drying. Eyeballs were cryofixed using a rapid freezing cryotechnique, and then sliced in the cryostat machine. The slices were sandwiched between glass slides, freeze-dried, and analyzed with confocal Raman microscopy. Important areas including various eyeball tissue layers were selected using bright-field microscopy, and then the Raman spectra were obtained at 240 locations. Four typical patterns of Raman spectra were electronically mapped on the specimen images obtained by the bright-field microscopy. Tissue organization was confirmed by embedding the same eyeball slice used for Raman spectra into epoxy resin and the thick sections were prepared with the inverted capsule method. Each Raman spectral pattern represents a different histological layer in the eyeball which was mapped by comparing the images of toluidine blue staining and Raman mapping with different colors. In the choroid and pigment cell layer, the Raman spectrum had two peaks, corresponding to melanin. Some of the peaks of the Raman spectra obtained from the blood vessels in sclera and the photoreceptor layer were similar to those obtained from the purified hemoglobin and rhodopsin proteins, respectively. Our experimental protocol can distinguish different tissue components with Raman microscopy; therefore, this method can be very useful for examining the distribution of a biological structures and/or chemical components in rapidly frozen freeze-dried tissue.

Chromosome territories (CTs) are intranuclear subregions occupied by individual chromosomes in an interphase cell. In this study, we investigated intranuclear CT positionings of chromosomes 10 (CS10), 18 (CS18), and 19 (CS19) in epithelial cells from four normal thyroid tissue (NT), four adenomatous goiters (AGs), six papillary carcinomas (PCs), and two undifferentiated carcinomas (UCs) using the multicolor fluorescence in situ hybridization method. In the NT and AGs, the radial positionings of CS10 and CS18 were detected at the periphery of nuclei in more than 60% and 80% of cells, respectively, whereas the radial positioning of CS19 was in the central region of the nuclei in more than 80% of cells. In the PCs, radial positioning pattern of CS10 and CS18 were similar to that in the NT. The nuclei with centrally located CS19 in PCs were less frequent than those in NT cells ( p < 0.01). On the other hand, UCs with cells having DNA amplification demonstrated the locational abnormalities of the CS10, CS18, and CS19 radial positions. These findings indicate that alteration of CT positioning could be related to DNA amplification and, morphologically, may explain the nuclear atypia that accompanies the abnormal chromatin feature.

At axon initial segments and nodes of Ranvier in neurons, the spectrin membrane skeleton plays roles in physically stabilizing the plasma membrane integrity and in clustering voltage-gated sodium channels for proper conduction of the action potential. beta IV-Spectrin, an essential component of the membrane skeleton at these sites, has an N-terminal-truncated isoform, 16, which is expressed at much higher levels than the full-length isoform Sigma 1. To investigate the role of beta IV-spectrin Sigma 6, we generated Sigma 1-deficient mice with a normal level of Sigma 6 expression (Sigma 1(-/-) mice), and compared their phenotypes with those of previously generated mice lacking both Sigma 1 and Sigma 6 (Sigma 1 Sigma 6(-/-) mice). The gross neurological defects observed in Sigma 1 Sigma 6(-/-) mice, such as hindleg contraction, were apparently ameliorated in Sigma 1(-/-) mice. At cellular levels, Sigma 1 Sigma 6(-/-) and Sigma 1(-/-) neurons similarly exhibited waving and swelling of the plasma membrane at axon initial segments and nodes of Ranvier. By contrast, the levels of ankyrin G and voltage-gated sodium channels at these sites, which are significantly reduced in Sigma 1 Sigma 6(-/-) mice, were substantially recovered in Sigma 1(-/-) mice. We conclude that the truncated beta IV-spectrin isoform Sigma 6 plays a specific role in clustering voltage-gated sodium channels, whereas it is dispensable for membrane stabilization at axon initial segments and nodes of Ranvier.

By means of electron holographic visualization of detailed electric potential distribution around sciatic nerve tissues coated with C and OsO4, we show that the steady state of these specimens subjected to intense charging with electron irradiation is accompanied with a dynamic motion of collective secondary electrons; the secondary electrons emitted from the coated specimens revolve around the positively charged specimens forming stationary orbits. Further, this study clarified the possibility of the direct visualization of a part of the orbits of the collective secondary electrons without disturbing their motions.

A middle-aged Japanese woman visited the Orthopedics Department of Nihon University Nerima Hikarigaoka Hospital complaining of pain in the left hip joint that had started approximately 8 months earlier. Following several examinations, including imaging diagnoses, an incisional biopsy demonstrated a malignant acetabular bone tumor, which was removed and examined by a quick-freezing and deep-etching (QF-DE) method, conventional electron microscopy, and light microscopy. Histologically, the tumor was a chondrosarcoma with marked myxoid changes. An interesting extracellular matrix was observed by the QF-DE method. The myxoid area consisted of a fine meshwork of proteoglycans (PG) without obvious aggrecans, which resembled that of PG usually present in the pericellular matrix of normal cartilage. Thin collagen fibrils with pleated surface structures of regular periodicity were also seen, which were sparsely distributed in wide areas except for the pericellular matrix. These collagen fibrils were of the type that are mainly located in the pericellular side of the territorial matrix in normal cartilage. A myxoid matrix consisting of thin collagen fibrils on the background of pericellular type PG suggested that the myxoid matrix in the chondrosarcoma resembled those of the pericellular and pericellular sides of the territorial matrices in normal cartilage.

The intestinal subepithelial myofibroblasts ( ISEMFs) are located in the lamina propria under the epithelial cells. ISEMFs are thought to have an important role in protecting and maintaining the integrity of the epithelial cell layer and also in the process of wound healing. In this study, we report that the membrane-bound proteoglycan NG2 is abundantly distributed in the ISEMF layer of the mouse and human intestines. NG2 immunostaining in this layer is distributed with similar intensity from the crypt to villi. NG2 is also immunolocalized along the membranes of smooth muscle cells in the intestinal muscle layer. However, skeletal and cardiac muscles are not immunostained for NG2, demonstrating selective expression of the proteoglycan by smooth muscle cells. Using electron microscopy, NG2 immunoreactivity was strongly observed along the cell membranes of ISEMF, with weak diffusion into the neighboring matrix, indicative of the presence of some "shed" NG2. This first report of NG2 proteoglycan expression by ISEMF provides insights into the nature of the interaction of these cells with extracellular matrix and/or intestinal epithelial cells.

Distribution of serum proteins in renal glomeruli is important for histopathology in medical and biological fields, but mechanisms of their passage through glomerular capillary loops (GCL) are still difficult to clarify. We have tried to visualize topographical changes of the serum proteins passing through GCL by "in vivo cryotechnique" in combination with immunohistochemistry. Albumin and immunoglobulin G (IgG), Ig kappa light chain and IgG1 heavy chain were mainly immunolocalized in GCL, but not colocalized with zonula occludens-1 (ZO-1) under normotensive condition. Under heart-arrest condition and in quick-frozen fresh tissues, albumin and kappa light chain were immunolocalized in Bowman's space, indicating their passage caused by the stoppage of blood supply. However, under acute hypertensive condition, they were more clearly immunolocalized along basement membranes and in the Bowman's space, indicating their increased passage through GCL. IgG was also more clearly localized in mesangial areas under acute hypertension, compared with that under the normotensive or heart-arrest condition. This study is the first direct visualization for glomerular passage of serum proteins under abnormal hemodynamic conditions by the "in vivo cryotechnique", and the experimental protocol will be useful for morphofunctional examination of living mouse GCL and immunohistochemical analyses of dynamically changing proteins.

Although the morphology and molecular distribution in animal liver tissues have been examined using conventional preparation methods, the findings are always affected by the technical artifacts caused by perfusion-fixation and tissue-resection. Using "in vivo cryotechnique" (IVCT), we have examined living mouse livers with histochemical, immunohistochemical and ultrastructural analyses. In samples prepared by IVCT, widely open sinusoids with many flowing erythrocytes were observed under normal blood circulation, and their collapse or blood congestion was seen in ischemic or heart-arrested mice. In contrast, the sinusoidal cavities were artificially dilated by perfusion-fixation, and collapsed by immersion-fixation and quick-freezing (QF) methods of resected tissues. The immunoreactivity of serum albumin and immunoglobulin G and intensity of periodic acid-Schiff-staining in hepatocytes were well preserved with the QF method and IVCT. Furthermore, following tissue resection, serum proteins were rapidly translocated into hepatocytes as demonstrated by immunoreactions on QF tissues frozen 1 or 5 min after resection. Translocation was not observed in IVCT samples, indicating that IVCT could be useful to examine cell membrane permeability of hepatocytes under different pathological conditions. Both dynamic morphology and immunodistribution of soluble components in living mouse livers, reflecting their physiological and pathological states, can be precisely examined by IVCT with higher time-resolution.

To identify the distribution of endogenous serum proteins in living mouse renal glomeruli under various hemodynamic conditions, we used the periodic acid-Schiff (PAS) and its fluorescence emission as a marker for the glomerular basement membrane (GBM). The immunostaining for collagen type IV was hardly observed without microwave treatment in specimens prepared by an "in vivo cryotechnique". However, PAS staining and its fluorescence emission could be clearly visualized at the GBM with the "in vivo cryotechnique". Under normotensive conditions, immunoreaction products of albumin and immunoglobulin G heavy and light chains (IgG(H+L)) were localized within glomerular capillary loops (GCL) but not colocalized with the PAS fluorescence emission of the GBM. Under heart-arrest conditions and with quick-freezing of resected tissues, albumin, IgG (H+L), immunoglobulin kappa light chain, and IgG1 heavy chain (IgG1) were immunolocalized within the GCL and mesangial areas, but only albumin and the kappa light chain were additionally immunolocalized in Bowman's space, indicating their passage through the GBM. Under acute hypertensive conditions, both albumin and the kappa light chain, but not IgG1, were clearly immunolocalized along the GBM and in the Bowman's space, indicating their increased passage through the GBM. The overlapping areas of PAS fluorescence emission and the albumin or kappa light chain appeared to be larger with quick-freezing and under the heart arrest or acute hypertensive conditions than under normal circulation, whereas those of PAS emission and IgG1 did not differ among these conditions. The serum proteins passing through the GBM were clearly visualized with the "in vivo cryotechnique", immunofluorescence staining, and PAS fluorescence emission.

The membrane-associated cytoskeletal proteins, including protein 4.1 family, play important roles in membrane integrity, protein targeting, and signal transduction. Although protein 4.1G (4.1G) is expressed ubiquitously in mammalian tissues, it can have very discrete distributions within cells. The present study investigated the expression and distributions of 4.1G in rodent sciatic nerve. Northern and Western blot analysis detected abundant 4.1G mRNA and protein in rat sciatic nerve extracts. Immunohistochemical staining with a 4.1G-specific antibody and double immunolabeling with E-cadherin, beta IV spectrin, and connexin 32 detected 4.1G in paranodal loops, Schmidt-Lanterman incisures, and periaxonal, mesaxonal, and abaxonal membranes of rodent sciatic nerve. Immunoelectron microscopy confirmed the immunodistribution of 4.1G in Schwann cells. In developing mouse sciatic nerves, 4.1G was diffusely distributed in immature Schwann cells and gradually localized at paranodes, incisures, and periaxonal and mesaxonal membranes during their maturation. These data support the concept that 4.1 G plays an important role in the membrane expansion and specialization that occurs during formation and maintenance of myelin internodes in the peripheral nervous system. (c) 2006 Wiley-Liss, Inc.

The lamellar body is a membranous structure periodically laminating in vesicles that is known as the most distinctive feature of type II pneumocytes by conventional preparation methods for transmission electron microscopy. The quick-freezing and freeze-drying method, followed by osmium tetroxide vapor-fixation (QF-FD-OsV), was performed to examine the in situ morphology of the lamellar body in type II pneumocytes of living mouse lungs. Typical lamellar structures were rarely seen in vesicles of the type 11 pneumocytes, but amorphous components and dispersed stripes were often detected in the vesicles, as revealed by the OF-FD-OsV method. To clarify how the lamellar body was formed during the conventional preparation steps, lung tissues of mice were treated with different fixation procedures, such as immersion-fixation with osmium tetroxide or perfusion-fixation with glutaraldehyde followed by osmium tetroxide, in combination with alcohol dehydration or QF-FD-OsV. In addition to lamellar bodies of type 11 pneumocytes in the specimens with alcohol dehydration, some lamellar structures were also formed even with the QF-FD-OsV method. These findings suggest that the labile lamellar body is easily modified and formed during both chemical fixation and alcohol dehydration steps.

The purpose of this study is to analyze the time-dependent molecular states of rhodopsin (Rho) phosphorylation in the specimens originating from eyeballs cryoimmobilized in situ in living animals. Whole eyeballs of living mice under various dark- and light-exposure conditions were quickly frozen using the in vivo cryotechnique with isopentane-propane cryogen cooled down in liquid nitrogen (-196C). The frozen whole-mount eyeballs were freeze substituted in acetone containing paraformaldehyde and embedded in paraffin wax. Deparaffinized sections were immunostained with anti-phosphorylated (334)Ser Rho (PRho334) antibody. Immunoreactivity of P-Rho334 was specifically recognized in the outer segments of mouse retinas exposed to daylight. in the 12-h dark-adapted retinas, P-Rho334 immunoreactivity was completely eliminated. Moreover, in other retinas dark adapted for 12 or 36 hr and then exposed under the safety red light for 2 min, it was still barely recognized. Even in the eyeballs exposed to strong visible light for 10 sec, it was not detected. However, after 30, 60, and 180 sec of visible light exposure, P-Rho334 immunoreactivity was definitely recovered, similar to that under daylight condition. This is a new immunohistochemical approach to visualize the time-dependent Rho phosphorylation of living mice using the in vivo cryotechnique, in which changes could be detected within seconds following exposure to light.

For analyses of dynamic ultrastructures of erythrocyte intramembranous particles (IMPs) in situ, a quick-freezing method was used to stabilize the flow behavior of erythrocytes embedded in vitreous ice. Fresh human blood was jetted at various pressures through artificial tubes, in which the flowing erythrocytes were elongated from biconcave discoid shapes to elliptical ones, and quickly frozen in liquid isopentane-propane cryogen (-193 degrees C). They were freeze-fractured using a scalpel in liquid nitrogen, and routinely prepared for replica membranes. Many IMPs were observed on the protoplasmic freeze-fracture face (P-face) of the erythrocyte membranes. Some control erythrocytes under nonflowing or stationary conditions showed IMPs with their random distribution. However, other jetted erythrocytes under flowing conditions showed variously sized IMPs with much closer distribution. They were also arranged into parallel rows in some parts, and aggregated together. This quick-freezing method enabled for the first time the visualization of time-dependent topology and the molecular alteration of IMPs in dynamically flowing erythrocytes.

A case of elastofibroma in a middle-aged Japanese woman was examined by the quick-freezing and deep-etching (QF-DE) method, as well as by immunohistochemistry and conventional electron microscopy. The slowly growing tumor developed at the right scapular region and was composed of fibrous connective tissue with unique elastic materials called elastofibroma fibers. A normal elastic fiber consists of a central core and peripheral zone, in which the latter has small aggregates of 10 nm microfibrils. By the QF-DE method, globular structures consisting of numerous fibrils (5-20 mn in width) were observed between the collagen bundles. We could confirm that they were microfibril-rich peripheral zones of elastofibroma fibers by comparing the replica membrane and conventional electron microscopy. One of the characteristics of elastofibroma fibers is that they are assumed to contain numerous microfibrils. Immunohistochemically, spindle tumor cells showed positive immunoreaction for vimentin, whereas alpha-smooth muscle actin, desmin, S-100 protein and CD34 showed negative immunoreaction. By conventional electron microscopy, the tumor cell had thin cytoplasmic processes, pinocytotic vesicles and prominent rough endoplasmic reticulum. Abundant intracytoplasmic filaments were observed in some tumor cells. Thick lamina-like structures along with their inner nuclear membrane were often observed in the tumor cell nuclei. The whole image of the tumor cell was considered to be a periosteal-derived cell, which would produce numerous microfibrils in the peripheral zone of elastofibroma fibers. This study indicated that the QF-DE method could be applied to the pathological diagnosis and analysis of pathomechanism, even for surgical specimens obtained from a patient.

A new 'cryobiopsy' (CB) technique has been invented for freezing the functioning livers of living mice in vivo without stopping their blood circulation. Livers of anesthetized mice were pinched off with pre-cooled CB forceps and immediately plunged into isopentane-propane cryogen. They were routinely freeze-substituted in acetone containing paraformaldehyde for light microscopy (LM) or osmium tetroxide for scanning electron microscopy (SEM). By freeze-fracturing some of them with a scalpel in liquid nitrogen before the freeze-substitution, well-preserved tissue areas were exposed only for SEM. They were either embedded in paraffin wax for LM or infiltrated with t-butyl alcohol followed by freeze-drying for SEM. Serial paraffin sections were stained with hematoxylin-eosin (HE) or histochemical periodic acid-Schiff (PAS) reaction. By HE-staining, the tissue surface areas were often compressed with the CB forceps and sinusoidal erythrocytes became aggregated side by side. In slightly deeper tissue areas, however, hepatic sinusoids were widely open with flowing erythrocytes. Lots of PAS-reaction products were well preserved in hepatocytes of the CB specimens. On the contrary, they were unevenly distributed in hepatocytes of conventionally quick-frozen specimens, and often lost in those of the conventionally dehydrated specimens. By SEM, some cell organelles, such as mitochondria and endoplasmic reticulum, and also dilated fenestrae of endothelial cells, open Disse's spaces and bile canaliculi appeared to be under normal blood circulation in the prepared CB samples. The new CB technique would be easy and useful for repeated examination of functioning organs of a living animal.

Although it was reported that protein 4.1 G, a cytoskeletal protein characterized by its general expression in the body, interacts with some signal transduction molecules in the central nervous system (CNS), its distribution and significance in vivo remained to be elucidated. In the present study, we have identified 4.1 G-positive cells in the rodent CNS, and demonstrated its immunolocalization in the developing mouse CNS. In the rodent CNS, 4.1 G was colocalized with markers for microglia, such as CD45, OX-42 and ionized calcium-binding adapter molecule 1 (Iba1), but not with markers for neuronal or other glial cells. Additionally, colocalization of 4.1 G and A1 adenosine receptor was observed in the mouse cerebrum. In a mixed glial culture, most OX-42-positive microglia were positive for 4.1 G, and 4.1 G isoforms of the same molecular weight as in the rat brain were expressed in cultured microglia, where 4.1 G mRNA was detected by RT-PCR. In the developing mouse cerebral cortex, 4.1 G was detected in immature microglia, which were positive for Iba1. These results indicate that 4.1 G in the CNS is mainly distributed in microglia in vivo. Considering the interactions between 4.1 G and the signal transduction molecules, putative roles have been propsed for 4.1 G in microglial functions in the CNS.

Protein 4.1 families have recently been established as potential organizers of an adherens system. In the adult mouse testis, protein 4.1 G (4.1 G) localized as a line pattern in both basal and adluminal compartments of the seminiferous tubules, attaching regions of germ cells and Sertoli cells. By double staining for 4.1G and F-actin, their localizations were shown to be different, indicating that 4.1 G was localized in a region other than the basal and apical ectoplasmic specializations, which formed the Sertoli-Sertoli cell junction and Sertoli-spermatid junction, respectively. By electron microscopy, immunoreactive products were seen exclusively on the cell membranes of Sertoli cells, attaching to the various differentiating germ cells. The immunolocalization of cadherin was identical to that of 4.1G, supporting the idea that 4.1G may be functionally interconnected with adhesion molecules. In an experimental mouse model of cadmium treatment, in which tight and adherens junctions of seminiferous tubules were disrupted, the 4.1G immunostaining in the seminiferous tubules was dramatically decreased. These results indicate that 4.1G may have a basic adhesive function between Sertoli cells and germ cells from the side of Sertoli cells.

DNA-negative Dane particles have been observed in hepatitis B virus (HBV)-infected sera. The capsids of the empty particles are thought to be composed of core protein but have not been studied in detail. In the present study, the protein composition of the particles was examined using new enzyme immunoassays for the HBV core antigen (HBcAg) and for the HBV precore/core proteins (core-related antigens, HBcrAg). HBcrAg were abundant in fractions slightly less dense than HBcAg and HBV DNA. Three times more Dane-like particles were observed in the HBcrAg-rich fraction than in the HBV DNA-rich fraction by electron microscopy. Western blots and mass spectrometry identified the HBcrAg as a 22-kDa precore protein (p22cr) containing the un-cleaved signal peptide and lacking the arginine-rich domain that is involved in binding the RNA pregenome or the DNA genome. In sera from 30 HBV-infected patients, HBcAg represented only a median 10.5% of the precore/core proteins in enveloped particles. These data suggest that most of the Dane particles lack viral DNA and core capsid but contain p22cr. This study provides a model for the formation of the DNA-negative Dane particles. The precore proteins, which lack the arginine-rich nucleotide-binding domain, form viral RNA/DNA-negative capsid-like particles and are enveloped and released as empty particles.

The polarized architecture of epithelial cells is a fundamental determinant of cell structures and functions. Both formation and orientation of proper epithelial polarity are needed for cell-cell or cell-matrix adhesion, signal transduction and cytoskeletal interactions of multimolecular complexes at apical, lateral and basal cell membranes. These cell membrane domains are usually segregated by some junctional complexes. Recent molecular genetic studies on the anchor structure between myelin sheaths and axons have indicated the specific molecular organization for polarization of axolemma and the myelin sheaths at paranodes, termed 'septate-like junctions'. It was also speculated that other mammalian organs may use a similar junctional system. The protein 4.1B was originally found to be localized in paranodes and juxtaparanodes of myelinated nerve fibers. Our recent immunohistochemical studies on protein 4.1B have indicated its significance for the cell-cell and/or cell-matrix adhesion in various rodent organs. The protein 4.1 family of proteins have been supposed to possess variable molecular domains relating to cell adhesion, ion balance, receptor responses and signal transduction. Therefore, more precise studies on the molecular structure and the functional domains of protein 4.1B, as well as on its changes under physiological and pathological conditions, may provide a clue for organogenesis in various mammalian organs.

In this experiment, we performed the "in vivo cryotechnique" in tandem with fluorescence microscopy. The fluorescein isothiocyanate (FITC)-conjugated goat anti-rabbit immunoglobulin (IgG) antibody (FITC-IgG) was directly injected into mouse livers or kidneys, which were then frozen in vivo by pouring an isopentane-propane mixture (-193 degrees C) cooled in liquid nitrogen over these living organs. The organs were subsequently freeze-substituted in acetone containing paraformaldehyde at about -80 degrees C, then gradually brought up to a room temperature, infiltrated with 30% sucrose and refrozen. Some well-frozen areas 300-400 mu m below the frozen tissue surface were cryocut into several slices. The slices were observed under the fluorescence microscope. By examining the distribution of FITC-IgG in the frozen livers, some aspects of functional blood circulation in the liver, such as the concept of the liver lobule, were reconfirmed. This also confirmed that the blood flow in the liver after the FITC-IgG injection was normal. The subsequent preparation of the specimens with immunohistochemistry, using the tetramethylrhodamine (TRITC)-conjugated anti-mouse IgG antibody, allowed us to visualize the localizations of both the original mouse IgG and the injected goat IgG in the cryosections with different color images. The experimental protocol presented demonstrates the in situ localization of the various proteins labeled with fluorescent probes, and it can, in conjunction with immunohistochemistry, localize proteins in cells and tissues. (c) 2005 Wiley-Liss, Inc.

Intranuclear localization of signal molecules and chromosome territories has become more attractive in relation to postgenomic analyses of cellular functions. Cryotechniques and freeze-substitution (CrT-FS) have been generally used for electron microscopic observation to obtain better ultrastructure and immunoreactivity. To investigate benefits of applying the CrT-FS method to immunostaining of intranuclear signal molecules and FISH for chromosome territories, we performed an immunohistochemical study of phosphorylated cAMP-responsive element binding protein (pCREB) in mouse cerebellar tissues and a FISH study of chromosome 18 territory in human thyroid tissues using various cryotechniques. The immunoreactivity of pCREB was more clearly detected without antigen retrieval treatment on sections prepared by the CrT-FS method than those prepared by the conventional dehydration method. In the FISH study, more definite probe labeling of the chromosome territory could be obtained on paraffin sections by the CrT-FS method without microwave treatment, although such labeling was not clear even with microwave treatment on sections prepared by the routine dehydration method. The CrT-FS preserved relatively native morphology by preventing shrinkage of nuclei, and produced better immunoreactivity. Because the reduction of routine pretreatments in the present study might reveal more native morphology, the CrT-FS method would be a useful technique for intranuclear immunostaining and FISH.

Intranuclear localization of signal molecules and chromosome territories has become more attractive in relation to postgenomic analyses of cellular functions. Cryotechniques and freeze-substitution (CrT-FS) have been generally used for electron microscopic observation to obtain better ultrastructure and immunoreactivity. To investigate benefits of applying the CrT-FS method to immunostaining of intranuclear signal molecules and FISH for chromosome territories, we performed an immunohistochemical study of phosphorylated cAMP-responsive element binding protein (pCREB) in mouse cerebellar tissues and a FISH study of chromosome 18 territory in human thyroid tissues using various cryotechniques. The immunoreactivity of pCREB was more clearly detected without antigen retrieval treatment on sections prepared by the CrT-FS method than those prepared by the conventional dehydration method. In the FISH study, more definite probe labeling of the chromosome territory could be obtained on paraffin sections by the CrT-FS method without microwave treatment, although such labeling was not clear even with microwave treatment on sections prepared by the routine dehydration method. The CrT-FS preserved relatively native morphology by preventing shrinkage of nuclei, and produced better immunoreactivity. Because the reduction of routine pretreatments in the present study might reveal more native morphology, the CrT-FS method would be a useful technique for intranuclear immunostaining and FISH.

Recently, we have reported that the protein 4.1B immunolocalization occurred only in matured columnar epithelial cells of normal rat intestines. This finding suggested that protein 4.1B expression could be examined for a possible change during neoplastic transformation of the intestinal mucosa. In the present study, we first present the distribution of mouse protein 4.1B in normal intestinal epithelial cells and tumor cells using the adenomatous polyposis coli (Apc) mutant mouse model. A low level of protein 4.1B expression coincided with the phenotypic transition to carcinoma. To examine the protein 4.1B expression in human intestinal mucosa, we used another antibody against an isoform of the human protein 4.1B, DAL-1 (differentially expressed adenocarcinoma of the lung). Human DAL-1 was also expressed in matured epithelial cells in human colons, with a definite expression gradient along the crypt axis. In human colorectal cancer cells, however, DAL-1 expression was not detected. These results suggest that mouse protein 4.1B and human DAL-1 might have a striking analogy of functions, which may be integrally involved in epithelial proliferation. We propose that loss of protein 4.1B/DAL-1 expression might be a marker of intestinal tumors, indicative of a tumor suppressor function in the intestinal mucosa.

Poly (ethylene glycol)-cholesterol (PEG-Chol) consists of a hydrophilic PEG and hydrophobic cholesterol moiety. When PEG-Chol was applied to erythrocytes, the reagent quantitatively induced protrusions by exclusively distributing in the outer monolayer of the membrane. This kind of response has been regarded as a general response that reduces the stress of expansion of the outer monolayer. However, the relationship between the membrane architecture and the distribution of such molecules is unknown. In this study, we examined the distribution of tagged PEG-Chol along the shape change pathway. The echinocytic shape was initiated by the initial formation of bumps on the rim of the discoid, which subsequently elongated as protrusions. These protrusions contained aggregates of granular structures, which appeared to accommodate the increase in the outer monolayer area. At higher concentrations, PEG-Chol further induced sphero-echinocytosis that resulted in numerous branched protrusion processes. We found that PEG-Chol was exclusively distributed in these protrusions and, in particular, accumulated at the tips. These results suggested that externally intercalated PEG-Chol was sequestrated from erythrocytes as membrane protrusions through an as-yet-unknown mechanism.

Recent molecular studies on anchoring structures between myelin sheaths by glial cells (oligodendrocytes and Schwann cells (Sc) in the central (CNS) and peripheral nervous system (PNS), respectively) and axons indicated protein-protein interaction for the polarization of paranodes in the axons. The protein 4.1 (4.1) family was originally found in erythrocytes as a component of membrane skeletons, and genetic approaches revealed the precise family members. One of them, 4.1 B, has been reported to be localized in paranodes and juxtaparanodes of myelinated axons. In this study, in addition to the myelinated axons, we also present the localization of 4.1 B in nerve fibers in the adult mouse enteric nervous system, a subpopulation of mature unmyelinated nerve fibers in PNS. Ultrastructurally, 4.1 B localized along the membranes of unmyelinated axons. Such unmyelinated axons were surrounded only by Sc, suggesting that the 4.1 B may also have a role in direct Sc-axon interactions and maturation of the axons, as well as myelinating glial cell-axon interactions. (C) 2004 Elsevier Ireland Ltd. All rights reserved.

Cell-cell adhesion is crucial not only for mechanical adhesion but also for tissue morphogenesis. Protein 4.1B, a member of the protein 4.1 family named from an erythrocyte membrane protein, is a potential organizer of an adherens system. In adult mouse seminiferous tubules, protein 4.1B localized in the basal compartment, especially in the attaching region of spermatogonia and Sertoli cells. Protein 4.1B localization and appearance were not different in each spermatogenic stage. Developmentally, protein 4.1B was not detected at postnatal day 3 (P3), was diffusely localized at P15, and was found in the basal compartment during the third week. By double staining for protein 4.1B and F-actin, their localizations were shown to be different, indicating that protein 4.1 B was localized in a region lower than the basal ectoplasmic specialization that formed the Sertoli-Sertoli junction. By electron microscopy, immunoreactive products were seen mainly on the membranes of Sertoli cells. In the W/W-v mutant mouse, the seminiferous epithelium had few germ cells. Protein 4.1 B and beta-catenin were not detected, although the basal ectoplasmic specialization was retained. These results indicate that protein 4.1 B may be related to the adhesion between Sertoli cells and germ cells, especially the spermatogonium.

Protein 4.1 family proteins are thought to interact with membrane proteins and also membrane skeletons. In this study, immunohistochemical studies by light and electron microscopy were performed with a specific antibody against protein 4.1B. Specific protein 4.1B immunolabeling was observed in simple columnar epithelium in the adult rat large intestine, small intestine and stomach. Protein 4.1B immunolabeling was localized along the membranes facing the adjacent cells (lateral portion) and also facing the extracellular matrix (basal portion). Moreover, a spatial protein 4.1B expression gradient was observed along the crypt-villus axis of the rat small and large intestinal epithelium: strong protein 4.1 expression was present within the villus, with the crypt showing barely any detectable protein 4.1B. The expression of protein 4.1B was not detected in the stratified squamous epithelium in the Forestomach or the esophagus. By immunoelectron microscopy, the immunolabeling of the cells was observed to be restricted to the cytoplasmic side just beneath the plasma membrane, including the membranes adjacent to the next cells, except for the tight junctions. We conclude that the protein 4.1B expression pattern is related to the maturation of simple columnar epithelium in the rat digestive system, probably by the effect of adhesion.

A quick-freezing and deep-etching method in combination with replica immunoelectron microscopy was applied for examining localization of hyaluronic acid and fibronectin on the upper surface layer of rat mandibular condylar cartilage. Rat temporomandibular joints were dissected with articular disks in order to leave the articular cartilage surface intact. The disks were slightly cut with razor blades for exposing the condylar articular cartilage surface. They were quickly frozen with the isopentane-propane cryogen (-193degreesC) and prepared for freeze-fracturing and deep-etching replica membranes. They were additionally treated with 5% SDS and 0.5% collagenase to keep some antigens attached on the replica membranes. After such a treatment, a routine immunogold method was applied for clarifying the localization of hyaluronic acid and fibronectin in the upper surface layer. Small immunogold particles for hyaluronic acid were mainly localized around upper filamentous networks covered with amorphous materials, but large immunogold ones for fibronectin were localized on deep thicker fibrils. We have revealed the native architecture of the upper surface layer of mandibular condylar cartilage on the replica membranes and also three-dimensional localization of hyaluronic acid and fibronectin by the immunogold method.

Protein 4.1 family proteins are supposed to interact with intramembranous proteins and membrane skeletons. Protein 4.1B, one of the family proteins, was recently reported to be localized in basolateral regions of mouse renal proximal tubules. In this study, we extended the idea that protein 4.1B may be related to ion balance in the region by immunohistochemical studies by light and electron microscopy with our antibody against protein 4.1B. Protein 4.1B distribution in rodent kidneys was determined by comparing with lectin Lotus tetragonobulus agglutinin (LTA), a proximal tubule cell marker, and also with Na+/HCO3 - cotransporter-1 (NBC-1), being expressed in basolateral domains of segment S1 to S2 proximal tubule epithelial cells. Specific protein 4.1B immunolabeling was observed in cuboidal epithelial cells basolaterally, starting their localization from a urinary pole at the glomerulus, whereas the squamous epithelial cells of Bowman's capsules were immunonegative. Rat Bowman's capsules had no simple cuboidal cells, where no protein 4.1B immunostaining appeared. All the protein 4.1B-positive epithelial cells were LTA positive. By immunoelectron microscopy, protein 4.1B immunolabeling of the proximal epithelial cells was restricted to the basolateral membranes, including basal infoldings, whereas tight junctions were not immunolabeled. It is concluded that protein 4.1B might play a role related to membrane skeletal proteins in the basolateral membranes of S1 and S2 proximal tubule cells. Moreover, the immunolocalization of protein 4.1B was almost the same as that of NBC-1, indicating a possible function as a regulator of ion balance, such as Na+ and HCO3 - reabsorption.

Classic cerebellar anatomy is based on the characteristic array of lobes and lobules. However, there is substantial evidence to suggest that more fundamental architecture is built around arrays of parasagittal stripes, which encompass both the inputs and outputs of the Purkinje cells (PCs). Sphingosine kinase (SPHK) is an enzyme that converts sphingosine (Sph) into sphingosine-1-phosphate (SIP). Recent reports have indicated that ceramide, Sph, and SIP play a role in cell survival, growth, and differentiation in several cell types, including neurons. In this study, we examined the localization of SPHK in the mouse cerebellum by using immunohistochemistry. Anti-SPHK immunoreactivity appeared in the cerebellar molecular layer and the PC membranes. The staining pattern is striped. In the molecular layer, the staining pattern probably reflects dendritic spines and dendrites. By electron microscopy, peroxidase reaction product was deposited within dendrites especially along the plasma membranes near spines. Seen at higher magnification, the staining was in and near the postsynaptic complexes. By double immunostaining, the striped pattern of SPHK expression was shown to be identical to that revealed by anti-zebrin II, although the subcellular distribution within PC's is not. This is the first demonstration of the cerebellar compartmentation of an enzyme related to lipid metabolism, and as such, it provides an insight into the roles of SPHK and formation of SIP. The selective expression of SPHK in the zebrin II-immunoreactive PCs may explain their resistance to cell death when ceramide metabolism is disrupted, as in the acid sphingomyelinase knockout model of Niemann-Pick type A/B disease.

A 28-year-old woman had chief complaints of headache and a 40degreesC fever. At this time, findings indicative of inflammation including elevated CRP and increased WBC were observed, and E. coli was detected on blood and urine culture. As a result, the patient was diagnosed with pyelonephritis and sepsis. Furthermore, markedly increased hepatobiliary enzymes and elevated anti-mitochondrial antibody were confirmed. The administration of antimicrobial agents resulted in improvement of the pyelonephritis and sepsis and normalization of hepatobiliary enzyme and anti-mitochondrial antibody levels. It has been documented that the incidence of urinary tract infection is high among patients with primary biliary cirrhosis (PBC). The findings obtained from the present patient are of considerable interest in elucidating the mechanism of onset in PBC.

Protein 4.1 family proteins are thought to interact with membrane proteins and membrane skeletons. Immunohistochemical studies by light and electron microscopy were performed on mouse pancreas with a specific antibody against protein 4.1B. Specific protein 4.1B immunolabeling was observed on endocrine cells in the islets of Langerhans. Protein 4.1B localized along the plasma membranes facing adjacent cells. By immunoelectron microscopy, the immunolabeling of the cells was restricted to the cytoplasmic side just beneath their plasma membrane, including the membranes adjacent to neighboring cells, while the plasma membranes facing endothelial cells were not immunolabeled for protein 4.1B. The immunolocalization of E-cadherin was similar, if not identical, to that of protein 4.1B supporting the idea that protein 4.1B may be functionally interconnected with adhesion molecules. In a transgenic mouse model of pancreatic beta-cell carcinogenesis (Rip1Tag2), the loss of protein 4.1B expression coincided with the phenotypic transition from adenoma to carcinoma. Therefore, we propose a role of protein 4.1B as a connecting and/or signaling molecule between membrane architecture, cell adhesion, and tumor cell invasion in mouse pancreatic endocrine cells.