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Biomedical subjects

F Shimizu

Publications and source records attributed to F Shimizu.

At least 91 records · Page 5Linked to original sources
PubMed1996

Highly virulent strains of herpes simplex virus fail to kill mice following infection via gingival route.

Virulence of herpes simplex virus (HSV) in mice has been demonstrated to be dependent on the site of infection. In this experiment, pathogenesis of HSV was studied in 2 different routes of infection in a mouse model system. When BALB/c mice were infected with 5 x 10(3) plaque-forming units (PFU) of virulent HSV type 1 Miyama GC+ strain (HSV-1-GC+) intraperitoneally, all mice were dead in 6 to 9 days. HSV-1-GC+ was recovered from organs such as the cerebrum, cerebellum, brainstem, and spleen 2 to 5 days after infection, but not from other organs such as trigeminal ganglia. However, if mice were infected in the maxillary gingiva with 1.0 x 10(7) PFU of HSV-1-GC+, all mice survived. HSV-1-GC+ was recovered from the trigeminal ganglia and brainstem 2 to 5 days after infection, but not from other organs tested. When mice were infected in maxillary gingiva with HSV-1-GC+, followed by the intraperitoneal injection of 6 mg of cyclophosphamide 72 hrs after virus infection, all mice were dead within days. Immunofluorescent and hematoxylin-eosin staining of gingival tissue sections revealed that when mice were infected in maxillary gingiva with HSV-1-GC+, 3 times as many gamma delta T-cells and 5 times as many polymorphonuclear cells can be detected in sections of maxillary gingiva when compared with non-infected mice. These data show that the gingiva of mice is considerably more resistant to infection with HSV, compared with the peritoneal cavity, and suggest the possible presence of an oral defense mechanism which might be different from that in the peritoneal cavity.

Animals↗
PubMed1996

Macrophagic cells outgrowth from normal rat glomerular culture: possible metaplastic change from podocytes.

One representative of a number of severe lesions that occur outside the glomerular capillaries and involve podocytes is crescentic glomerulonephritis. The question of whether the crescent-forming cells are derived from glomerular epithelial cells or monocytes/macrophages is highly controversial and has not yet been clarified. To investigate the pathophysiology of podocytes in crescentic glomerulonephritis, we attempted to establish methods for culturing cells confirmed to be derived from podocytes, focusing particularly on the relationship between podocytes and macrophages. Nonadherent cells of unknown origin that grew from normal rat isolated glomerular cultures increased in number, reaching a total of 3.5 x 10(5)/ml on Day 11. They showed several characteristics of macrophages, the expression of specific antigens and enzymes, morphology, and production of H2O2. They expressed Fx1A but lacked the expressions of Thy1.1 or factor VIII. A morphologic kinetic study on Days 3 to 11 of culture showed that the cells with foot processes on the glomerular basement membrane changed into macrophagic cells (MC) and migrated from the glomeruli. Immunofluorescence double staining indicated that the cells that migrated from the glomerular surface on Day 8 were both anti-podocalyxin- and ED-1-positive. Furthermore, immunoelectron microscopy revealed that the ED-1-positive cells were located on the glomerular basement membrane. Pretreatment with anti-macrophages and -Thy1.1 antibodies, both with complement, did not reduce the number of MC, whereas pretreatment with puromycin aminonucleoside predominantly reduced the number of MC. A predominant decrease in the number of glomerular macrophages by gamma-irradiation did not result in a reduction of the number of MC. MC derived from glomerular cultures of bone marrow chimeric rats expressed the la antigen originated from recipient, which indicates that MC is not derived from bone marrow cells. Macrophage colony-stimulating factor accelerated the speed of the change into MC, and granulocyte-macrophage colony-stimulating factor dramatically enhanced its degree with increase of cell number on Day 8. We concluded that podocytes change into MC in normal rat glomerular culture and that the change is enhanced by colony-stimulating factors. The results provide a completely new insight into the origin of crescent-forming cells.

Animals↗
PubMed1995

Cloning, sequencing and expression of a novel cDNA encoding human vacuolar ATPase (14-kDa subunit).

A cDNA encoding the 14-kDa subunit of vacuolar ATPase was cloned from human fetal brain. The sequence was composed of 680 nucleotides containing an open reading frame of 357 nucleotides. The deduced peptide sequence consisted of 119 amino acid residues with a calculated molecular weight of 13,369 Da and a pI of 5.19. Overall, this amino-acid sequence was respectively 69% and 70% identical to those of Manduca sexta and Drosophila melanogaster 14-kDa subunits, although the two representatives of Class Insecta were remarkably similar to one another (91% identity). Three regions in particular (the N-terminal, amino acids 5-36; the middle, residues 58-68; and the C-terminal, residues 88-118) were highly conserved. Hence, we think that the 14-kDa subunits have evolved from the same ancestral gene, and that the three conserved regions are important for the structure and function of vacuolar ATPase. A single 0.8-kb band was detected in various human tissues by Northern blot analysis. Since the human 14-kDa subunit is expressed ubiquitously, it might be a housekeeping protein. A separate transcript found in the cDNA library lacked a 6-bp segment in the 5' non-coding region (nucleotides -40 to -35) and also carried a 23C to T (8Thr to Ile) point mutation in the coding region; these minor differences likely reflected normal polymorphism.

Amino Acid Sequence↗
PubMed1995

Possible significance of VLA-4 (alpha 4 beta 1) for hematogenous metastasis of renal-cell cancer.

Very late antigen-4 (VLA-4) composed of alpha 4 and beta 1, a member of the beta 1-integrin subfamily, facilitates cell-to-cell interaction with vascular cell-adhesion molecule-1 (VCAM-1) on endothelial cells (EC). Attachment of blood-borne tumor cells to EC is a crucial step for hematogenous metastasis, and VLA-4-positive tumor cells can attach to EC by binding to VCAM-1. Renal-cell cancer (RCC) reveals proportionally greater percentages of metastases than other carcinomas at initial diagnosis. We investigated whether VLA-4 is expressed on RCC, and how such expression on RCC correlates with the metastatic potential of RCC. Immunohistochemical staining on 66 primary and 4 metastatic RCC showed that 4 out of 4 metastatic and 5 out of 8 primary RCC from patients with lung and/or brain metastases expressed alpha 4 and beta 1 chains. On the other hand, 13 of 58 RCC without metastases expressed alpha 4 chain, alpha 4 and beta 1 expressions were also detected on 5 out of 5 human RCC cell lines, ACHN, KRC/Y, A498, Caki1 and Caki2, by flow-cytometric analysis. Reverse-transcriptase-polymerase-chain-reaction (RT-PCR), followed by Southern-blot hybridization with cDNA probe for a alpha 4 chain, also confirmed mRNA production in 4 out of 5 RCC cell lines. Furthermore, adhesion of alpha 4-positive RCC cell lines to human umbilical-vein endothelial cells (HUVEC) was augmented by treatment of HUVEC with tumor necrosis factor-alpha (TNF-alpha). This adhesion was inhibited by anti-alpha 4 or anti-VCAM-1 antibodies, suggesting that VLA-4-VCAM-1 interaction was involved in the adhesion between RCC cells and HUVEC. Taken together, VLA-4 on RCC cells might play a crucial role in their hematogenous metastasis.

Adult↗
PubMed1995

Progressive renal lesions induced by administration of monoclonal antibody 1-22-3 to unilaterally nephrectomized rats.

A new animal model of progressive glomerulosclerosis was developed by administering a single i.v., injection of MoAb 1-22-3 to unilaterally nephrectomized rats. Renal morphological analysis revealed that glomerular lesions characterized by mesangial cell proliferation and mesangial matrix expansion were induced in about 95% of the glomeruli. Approximately 20% of the glomeruli of the unilaterally nephrectomized rats showed sclerosis or segmental sclerosis by week 6 after MoAb injection and crescent formation was observed in some glomeruli (ca 4%). Cellular infiltration was also noted in some parts of the interstitium. Increased expression of transforming growth factor-beta (TGF-beta) was observed in the unilaterally nephrectomized rats treated with MoAb 1-22-3, but we could not demonstrate pathological involvement of platelet-derived growth factor (PDGF), even though early-stage mesangial cell proliferation was observed. The mechanism of mesangial cell proliferation in this model remains to be elucidated. The relatively short period of time needed to induce the sclerotic changes in considered to be a great advantage of this model for clarifying the mechanisms involved in the chronic progression of mesangial proliferative glomerulonephritis.

Animals↗
PubMed1995

Strain variation in susceptibility to the development of monoclonal antibody 5-1-6-induced proteinuria in rats.

Susceptibility to the development of MoAb 5-1-6-induced proteinuria was investigated in four different rat strains, i.e. Brown-Norway (BN), Lewis (LEW), Sprague-Dawley (SD) and Wistar. An intravenous injection of 5 mg of MoAb 5-1-6 to female 7-week-old rats of a given strain induced massive proteinuria in BN, LEW and Wistar rats. However, SD rats developed almost no proteinuria. A similar tendency was observed in the second experiment, in which the injected dose of MoAb was adjusted according to the body weight of each rat (3 mg/100 g body weight). Immunofluorescence (IF) and immunoelectron microscopy (IEM) revealed no differences between the binding patterns of the MoAbs to normal rat kidneys derived from each strain. Quantitative study using 125I-labelled MoAb showed that there was no significant difference in the amount of antibody bound to the kidney 1 h and 5 days after injection between two rat strains, LEW and SD. Localization of 5-1-6 in vivo and its kinetics were investigated. In IF a linear-like pattern along capillary walls was observed 2 h after injection in both LEW and SD strains. This linear-like pattern was shifted to a granular pattern in proteinuric LEW rats 6 days after injection, whereas it remained linear-like in non-proteinuric SD rats. IEM confirmed this difference in the localization of injected MoAb 6 days after injection to LEW and SD rats also at the ultrastructural level. We conclude that there is a clear-cut strain difference in the development of proteinuria induced by MoAb 5-1-6. SD rats were less susceptible to MoAb-induced glomerular injury than BN, LEW and Wistar rats. Although the exact reason for strain variation in susceptibility to MoAb-induced proteinuria remains to be clarified, the movement of bound MoAb, presumably together with corresponding antigenic molecule along the glomerular epithelial cell surface followed by endocytosis into the epithelial cell, seems to be closely related to the induction of proteinuria.

Animals↗
PubMed1995

Visceral epithelial cells in rat glomerular cell culture.

The purpose of this study was to identify and characterize visceral epithelial cells (VECs) of renal glomeruli in culture. Such cells have been described variably as regular, polygonal cells showing a high rate of replication and a cobblestone-like appearance at confluence and also as irregular, arborized and often multinucleated cells showing a very limited proliferative capacity. We examined early outgrowths from the glomeruli by immunofluorescence microscopy using antibodies specific for VECs (anti-podocalyxin(1A), anti-pp44 and 5-1-6), for endothelial cells (anti-von Willebrand factor (vWF) and RECA-1) and for mesangial cells (anti-Thy-1). 1A and anti-pp44 reacted with several types of irregular, arborized cells, but never with regular, polygonal cells. 5-1-6 did not react with any of the cells. Neither the 1A- nor anti-pp44-positive cells (1A/pp44(+) cells) stained with anti-vWF, RECA-1 or anti-Thy-1. However, all the 1A/pp44(+) cells expressed desmin and vimentin but not cytokeratin. These results show that the 1A/pp44(+) cells are derived from VECs, supporting the idea that most polygonal cells in glomerular cultures are of parietal epithelial origin.

Animals↗
PubMed1995

Developmental expression of the nephritogenic antigen of monoclonal antibody 5-1-6.

The biogenesis of p51, the target of nephritogenic monoclonal antibody 5-1-6, was studied in the developing glomerulus by immunolocalization and metabolic labeling. The localization of p51 was compared with that of ZO-1, a component of the cytoplasmic face of the epithelial slit diaphragm, and with that of podocalyxin, and apical marker of the podocyte. p51 first became faintly, but clearly, detectable on the basal and lateral sides of the developing podocytes at the S-shaped body stage. Staining intensity increased with further maturation and was restricted to the visceral epithelial cells. On immunoelectron microscopy, the antigen was seen along the basal and lateral surfaces below occluding junction at the early capillary loop stage and later, with the interdigitation of foot processes, became concentrated in the slit pores. At no stage was p51 seen on the apical surface. p51 and ZO-1 were closely localized in the mature glomerulus but arrived at their final positions from opposite directions. p51 was on basal and podocalyxin was on apical sides of the glomerular epithelium from the S-shaped body stage onwards. Metabolic labeling studies showed that p51 is actively synthesized during initial glomerular development and that the rate of synthesis declines substantially with maturation. We conclude that p51 is primarily synthesized during the initial glomerular development, becomes concentrated in the slit pores of mature podocytes, and serves as a basal differentiation marker for podocytes.

Aging↗
PubMed1995

Production of transforming growth factor-beta by cultured rat mesangial cells.

The purpose of this study was to examine whether transforming growth factor-beta (TGF beta) acts as an autocrine cytokine in cultured mesangial cells. Measangial cell conditioned media (CM) were prepared and tested for their effect on mesangial cell proliferation. CM showed a concentration dependent inhibition on mesangial cell proliferation and the activity was enhanced by treating conditioned media with acid. Gel filtration analysis showed peak inhibitory activity to reside in fractions with an estimated molecular weight range of 16-30 KD. The activity was partially blocked by anti-TGF beta antibody, but not nonimmune control IgG. The presence of TGF beta was confirmed using the mink lung epithelial cell assay. Furthermore, the addition of anti-TGF beta antibody directly into culture media significantly enhanced mesangial cell proliferation. These results demonstrate that measangial cell produce both active and latent forms of TGF beta, which functions as an autocrine growth inhibitor for mesangial cells.

Animals↗
PubMed1994

Selective planting of cationized, haptenized ovalbumin on the rat tubular basement membrane.

We developed an experimental protocol for planting exogenous antigens with different molecular weights and charges on the constituents of the renal tubulointerstitium. The cationized antigens were injected selectively into the left renal arteries of Wistar rats. Antigen localization was documented by immunohistochemistry on frozen sections. Cationized bovine serum albumin (BSA; 68 kDa, isoelectric point = 9.5) localized almost exclusively along the glomerular capillary wall. After application of highly cationic polyethyleneimine, cationized BSA given subsequently was found in a linear distribution along the glomerular capillary wall and along the peritubular capillaries. The fate of highly cationized ovalbumin conjugated with trinitrophenol (TNP-OA), subjected to gel filtration to obtain monomers (42 kDa, isoelectric point > 10) differed; it was deposited in a linear pattern on the tubular basement membrane (TBM) and Bowman's capsule, and remained up to 36 h after injection. Noncationized, monomeric TNP-OA (42 kDa, isolectnic point = 4.6) showed fine granular deposition in the tubular epithelium exclusively. These findings indicate that the barrier of the glomerular BM acts selectively on antigens with different molecular weights. They either settle on the peritubular capillaries, after passing the glomerular, or reach the urinary space, after which they are reabsorbed by the tubular epithelial cells to reach the TBM.

Animals↗
PubMed1994

Effect of traditional Chinese medicine (sairei-to) on monoclonal antibody-induced proteinuria in rats.

The effects of traditional Chinese medicine (Sairei-to) on monoclonal antibody (mAb) inducing proteinuria were examined. Four hundred, 200 and 100 mg/kg body weight (BW) of Sairei-to and phosphate-buffered saline (PBS) as a control were injected intraperitoneally into four groups of female Wistar rats every day from 5 days before intravenous injection of mAb to the end of the experimental period. The amount of urinary protein excretion was significantly suppressed in roughly a dose-dependent manner. For example, 116.6 +/- 89.7 mg/day of proteinuria was observed in control groups compared to 4.2 +/- 15.2 mg/day in the 400 mg/kg BW of Sairei-to treated group 2 days after mAb injection (P < 0.01). Statistically significant (P < 0.01) differences were again observed in a repeat experiment (122.1 +/- 53.7 vs 10.2 +/- 10.1 mg/day on the 2nd day) without affecting the glomerular filtration rate. No significant difference was recognized between the total amount of mAb bound to glomeruli 1 h after mAb injection in Sairei-to-treated and non-treated rats, indicating that Sairei-to pretreatment has no effects on the number or quality of antigenic molecules. The effect of Sairei-to on a non-immunological model of proteinuria was also examined. No significant reduction of proteinuria by similar Sairei-to treatment was observed in aminonucleoside of puromycin nephropathy. The authors conclude that mAb-induced proteinuria in rats is significantly suppressed by the traditional Chinese medicine, Sairei-to.

Animals↗
PubMed1994

Nephrotoxic serum nephritis in nude rats: the role of cell-mediated immunity.

The role of T cell-mediated immunity in the early phase of nephrotoxic serum nephritis (NTN) was examined by transfer of pan T, CD8-positive, and CD4-positive cells. The disease was induced by transferring rabbit gamma-globulin (RGG)-sensitized T cells to nude (rnu/rnu) rats pretreated with a subnephritogenic dose (a dose insufficient to cause proteinuria) of nephrotoxic serum. Mild but abnormal proteinuria was detected, and macrophages showed significant accumulation in glomeruli. Transfer of not only RGG-sensitized CD4-positive cells but also CD8-positive cells separated by the T cell markers OX8 and OX38 using the panning method caused an increased accumulation of macrophages in isolated glomeruli. No host antibody against rabbit immunoglobulins was demonstrated either in glomeruli by immunofluorescence or sera by ELISA in the early disease phase. These findings support a pathological role of T cells in initiation of glomerular injury in NTN.

Animals↗
PubMed1994

Gene transfer into the rat renal glomerulus via a mesangial cell vector: site-specific delivery, in situ amplification, and sustained expression of an exogenous gene in vivo.

To evaluate the pathophysiological function of specific molecules in the renal glomerulus, selective, sustained, and modifiable expression of such molecules will be required. Towards achieving this end, we devised a gene transfer system using the glomerular mesangial cell as a vector for gene delivery. A reporter gene which encodes bacterial beta-galactosidase was introduced into cultured rat mesangial cells, and the stable transfectants were transferred into the rat kidney via the renal artery, leading to selective entrapment within the glomeruli. In the normal kidney, the reporter cells populated into 57 +/- 13% of glomeruli site specifically, and the expression of beta-galactosidase was sustained for 4 wk and declined thereafter. Within the glomerulus, some of the reporter cells remained in the glomerular capillaries, while others repopulated the mesangial area and, in part, extended their cytoplasmic processes toward the surrounding capillaries. When the cells were transferred into glomeruli subjected to transient mesangiolysis induced by monoclonal antibody 1-22-3, in situ expression of beta-galactosidase was amplified 7-12-fold, and the enhanced level of expression continued for up to 8 wk. The mesangial cell vector system thus achieves site-specific delivery of an exogenous gene into the glomerulus and is amenable to in situ amplification and sustained expression by preconditioning of the target site.

Animals↗
PubMed1994

Water and protein permeability is regulated by the glomerular epithelial slit diaphragm.

The glomerular barriers to water and macromolecular movement were examined 2 and 24 h after the administration of a monoclonal antibody (mAb) specific to an antigen located on the epithelial slit diaphragm and the external aspect of the glomerular basement membrane. By micropuncture techniques 2 h after mAb administration, single-nephron GFR (SNGFR) and plasma flow were unchanged but the glomerular capillary hydrostatic pressure gradient and glomerular capillary hydrostatic pressure were increased and the glomerular ultrafiltration coefficient (LpA) decreased to values that were 50% of the normal control. There was no increase in urinary protein excretion at 2 h. However, at 24 h after mAb, nephron plasma flow (SNPF) and SNGFR increased and the glomerular ultrafiltration coefficient returned to values indistinguishable from the normal control. At 24 h, there was a marked increase in protein excretion. The administration of meclofenamate decreased values for SNGFR and SNPF to normal. Immunoglobulin G was exclusively bound to glomerular capillary walls in a linear or continuous fashion at 2 h, but in a discontinuous, granular pattern at 24 h. These studies suggest that after mAb, important limiting glomerular barriers for hydraulic conductivity and protein excretion reside on the epithelial aspect of the glomerular capillary basement membrane, specifically at the level of the slit diaphragm. Studies also suggest that alterations in glomerular capillary hydraulic conductivity can be effectively separated from increases in macromolecular permeability.

Animals↗