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Biomedical subjects

H Sakaguchi

Publications and source records attributed to H Sakaguchi.

At least 253 records · Page 14Linked to original sources
PubMed1993

Analysis of proliferating biliary epithelial cells in human liver disease using a monoclonal antibody against DNA polymerase alpha.

The proliferative activity and ultrastructural characteristics of proliferating biliary epithelial cells were analysed immunohistocytochemically in 39 biopsied liver specimens from patients with acute viral hepatitis, chronic hepatitis and liver cirrhosis using a monoclonal antibody against DNA polymerase alpha (DNA-PA). In acute viral hepatitis with perivenular confluent necrosis, proliferation of typical bile ducts was found frequently in portal areas. In chronic aggressive hepatitis and cirrhosis, ductular proliferation of both typical and atypical forms was found in enlarged portal and periportal areas and in confluent necrotic areas. The number of proliferating biliary epithelial cells that stained positive for DNA-PA was small. There were very few positively stained cells in atypical bile ducts in confluent necrotic areas of cirrhosis. Atypical bile ducts seen in chronic aggressive hepatitis, cirrhosis and acute hepatitis with confluent necrosis were positively stained for both cytokeratins 8 and 19. In cirrhosis, the number of stained biliary epithelial cells in typical bile ducts was larger than the number of such cells in atypical bile ducts (P < 0.01). By electron microscopy, the cells positively stained for DNA-PA were mostly so-called clear cells with irregular nuclei containing coarse nucleoplasm, and a few small cells with scanty cytoplasm and few organelles.

Adult↗
PubMed1993

Partial cloning of the rat choline acetyltransferase gene and in situ localization of its transcripts in the cell body of cholinergic neurons in the brain stem and spinal cord.

We have isolated recombinant lambda (lambda) phages which contain a part of the rat choline acetyltransferase (ChAT) gene. Restriction and Southern blot analyses using synthetic oligonucleotides indicate that these clones overlap one another and contain at least four exons which reside in 16.4 kb of sequence encoding from the middle to the 3' end, but not the 5'-region, of the rat ChAT gene. Partial sequence analyses revealed that the clones contain an exon whose nucleotide sequence corresponds to a highly conserved region of ChAT during evolution. RNase protection mapping experiments show that sequences represented by this exon are expressed at high levels in the spinal cord of adult rats and at low but detectable levels in PC12 cells. By using the genomic sequences, including the exon, as a hybridization probe, we have detected ChAT mRNAs in situ in rat tissues. In situ hybridization experiments using radioactive and non-radioactive probes revealed that cholinergic motoneurons in the spinal cord, the laterodorsal tegmental nucleus as well as the hypoglossal nucleus in the brain stem were labeled, suggesting that the genomic sequence can be used as a probe to measure the ChAT mRNA levels in those cholinergic neurons. The results also indicate that the non-radioactive method gives a better resolution in localizing the expression of ChAT transcripts in the cytoplasm of cholinergic neurons.

Amino Acid Sequence↗
PubMed1993

Stable self-sustained potential oscillations across a membrane filter impregnated with triolein.

When applying constant electric current, periodic self-sustained potential oscillations with high stability are observed across a membrane filter impregnated with triolein, placed between KCl and NaCl aqueous solutions. Stability, reproducibility and controllability of the oscillation are much improved by the application of constant electric current compared with those obtained without application of electric current. Relations among value of electric current, base potential and period of the oscillations are studied, and it is concluded that the oscillation period can be controlled by base electric potential. Effects of temperature on the oscillations are investigated, and it is shown that Arrhenius plots for both base conductance and conductance amplitude of each oscillation fitted well to an individual straight line and that values of activation energies are similar to those of bulk salt solutions. From all data obtained it is suggested that the oscillations occur as a result of rhythmic repetition of opening and closing of hole(s) in the membrane, which is due to breakdown and restoration of a part of the membrane.

Cellulose↗
PubMed1993

Dissociation of clinical manifestation and histopathology in the course of mesangial injury by anti-thymocyte antibody.

Intravenous administration of heterologous anti-thymocyte antibodies, which react with rat mesangial cells, induced minimal mesangiolysis (6 hours to 3 days) followed by mesangial hypercellularity. Moreover, autologous immunoglobulins appeared in the mesangium within 1 or 2 weeks. At the same time, electron microscopy demonstrated mesangial deposits. Accompanying these pathological alterations, significant proteinuria developed. To accelerate an acute autologous immune reaction, rats were preimmunized with rabbit IgG prior to the injection of anti-thymocyte antibodies. They revealed marked mesangiolytic lesions 3 days after injection with deposition of autologous immunoglobulins and C 3 in the mesangium. In contrast, there was no significant proteinuria. Thus, mild pathological alterations in the mesangium induced by heterologous and subsequent autologous immune reactions caused proteinuria, and accelerated immune injury to the mesangium produced severe mesangiolysis without proteinuria. Based on these findings, it is suggested that the time-lapse between heterologous and autologous immune reactions to the mesangium influences the pathological alterations and clinical manifestations occurring in mesangial injury by anti-thymocyte antibody.

Animals↗
PubMed1993

High-density localization of ANP receptors in chondrocytes of eel gill cartilage.

Very high levels of atrial natriuretic peptide (ANP) receptor were found in a quite unexpected tissue, i.e., the chondrocyte of the eel gill cartilage. 125I-labeled ANP binding assay indicated that the eel gill contains large amounts of the receptor and its levels are much higher (> 10-fold) than those in the other tissues examined, including the brain, kidney, head kidney including steroidogenic interrenal cells, and gut. Autoradiography using gill sections revealed dense localization of ANP receptors in the chondrocytes of the cartilage as well as moderate localization in the parenchymal cells. Biochemical and pharmacological characterization of the chondrocyte receptor indicated that most of the receptors are type C receptors, having a broad ligand specificity and a reduced M(r) of 68,000. Because a hyaline cartilage in which chondrocytes reside lacks blood vessels, and all metabolic exchange is by slow diffusion through the matrix, the chondrocyte localization of the type C ANP receptor is notable and may stimulate not only chondrocyte research but also studies on physiological significance of the type C receptor, which is generally considered to be merely a clearance (silent) receptor.

Animals↗
PubMed1993

Lipoprotein glomerulopathy. Report of a normolipidemic case and review of the literature.

Lipoprotein glomerulopathy is a disease characterized by intraglomerular lipoprotein thrombi and abnormal lipid metabolism similar to type III hyperlipoproteinemia. Recently, glomerular lesions compatible with lipoprotein glomerulopathy were found in a 38-year-old man. In this case, plasma apolipoprotein (apo) E level was elevated, and the apo E isoform was heterozygous E2/3, similar to most of the reported cases of lipoprotein glomerulopathy. However, the plasma levels of triglyceride and total cholesterol were within their respective normal ranges. Review in 11 cases revealed that lipoprotein glomerulopathy was not always associated with hyperlipidemia, and that apo E abnormality was always recognized. These findings suggest that lipoprotein thrombi associated with lipoprotein glomerulopathy are not induced via systemic hyperlipidemia but may be formed by intraglomerular accumulation of lipoprotein composed of abnormal apo E.

Adult↗
PubMed1993

Steroid-responsive renal insufficiency due to idiopathic granulomatous tubulointerstitial nephritis.

A 26-year-old male was admitted to our hospital having suffered from subfever, sterile pyuria and renal insufficiency for 1 year. There had been no apparent hematuria/proteinuria, and evidence of infection, allergy or intoxication was not demonstrated. Open renal biopsy revealed severe tubulointerstitial changes with granuloma accompanied by neither caseous necrosis nor giant cells. Infiltrating cells mostly consisted of CD4 and CD8 T cells, and some proximal tubular cells presented MHC class II antigen. Following the negative culture of biopsied specimen for acid-fast bacilli, diagnosis of idiopathic granulomatous tubulointerstitial nephritis was made, and steroid therapy was started. Two months later, pyuria disappeared and renal function improved significantly, proving the effectiveness of steroid on idiopathic granulomatous tubulointerstitial nephritis.

Adult↗
PubMed1993

A case of collagenofibrotic glomerulopathy associated with hepatic perisinusoidal fibrosis.

A patient with collagenofibrotic glomerulopathy associated with hepatic persinusoidal fibrosis is described. Renal biopsy revealed that the glomerular tufts contained homogeneous material that was proved by electron microscopy to be collagen fibers. The material was reactive to anti-type III collagen monoclonal antibody. Liver biopsy also showed an increase of type III collagen fibers in the perisinusoidal area. Since the serum procollagen III peptide level was elevated in this patient, fibrosis may have been simultaneously activated in kidney and liver by some unknown condition.

Biopsy↗
PubMed1993

[Relationship between tissue concentrations of 5-FU and degeneration of tissues after UFT administration in patients with bladder tumor].

The relationship between the 5-FU concentration and tissue degeneration was studied in the bladder tumor tissue after UFT administration. In 12 patients with bladder tumor, UFT 400 mg/day was administered orally for about 2 weeks before TUR, and tegaful, 5-FU and uracil concentrations were examined in the blood and the tumor tissue taken about 6 hours after the last administration. Tumor tissue was also taken before and after the UFT administration, and the degree of cell degeneration due to UFT administration were evaluated by light and electron microscopy. The 5-FU concentration was significantly higher in the tumor tissue (0.078 +/- 0.091 microgram/g) than in the serum (0.017 +/- 0.010 microgram/ml). Signs of degeneration were observed in tumor cells after UFT administration in all 6 patients in whom the tumor tissue 5-FU concentration was 0.046 microgram/g or higher. Mitosis was not increased after UFT administration in any of the 12 patients.

Aged↗
PubMed1993

[Aortic valve replacement and coronary artery bypass grafting in a patient with a porcelain aorta due to aortitis syndrome].

Clamping a calcified aorta during cardiac operation increases the risk of cerebral embolism by aortic debris. We operated upon a 61-year-old female with severe angina pectoris due to aortic regurgitation and bilateral coronary calcific ostial stenosis associated with porcelain aorta secondary to aortitis syndrome. At operation, cardiopulmonary bypass was begun with profound hypothermia. Using an occlusion balloon catheter inflated in the ascending aorta, the calcified aorta was incised with scissors. However accidentally the balloon was ruptured by intimal calcification of the ascending aorta, and cardiopulmonary bypass was discontinued for 11 minutes under 20 degrees C hypothermia. Extensive removal of the intimal calcification of the ascending aorta was performed with care and then, the aorta was clamped. Aortic valve replacement and triple coronary bypass operation (SVG to LAD, SVG to LCX, GEA to RCA) were performed. The proximal anastomoses of the SVGs were made on the decalcified aortic wall. The postoperative course was uneventful and aortography revealed neither dissection nor dilatation of the ascending aorta following extensive decalcification procedure of the ascending aorta, and the 3 grafts were all patent. From the experience, we learned that extensive removal of calcification of the aorta can be successfully performed in porcelain aorta due to aortitis syndrome. For CABG in aortitis syndrome, the use of ITA is rarely possible, but the GEA may be a versatile graft.

Aorta↗
PubMed1993

[Cell viability assessment of cold-preserved (4 degrees C) and cryopreserved (-196 degrees C) allograft valves by flowcytometric analysis].

We introduced cryopreservation technique to store the allograft valve and subsequently commenced the use of the cryopreserved aortic allograft valve for aortic valve replacement. For the clinical use of the allograft valve, it is essential to evaluate the cell viability. We assessed cell viability of the allograft valve by flowcytometry (FCM), using a fluorescein diacetate (FDA)-propidium iodide (PI) stain. Pulmonary allograft valves were harvested from the cadavers with a consent. Of the 9 valves collected and sterilized in 4 degrees C antibiotic solution for 48 hours, 4 valves were stored under refrigeration (cold-preserved), and the remaining 5 valves were cryopreserved. The warm ischemic time from cardiac death to valve preservation was 7.3 +/- 5.4 hours. The cold-preserved valves were stored at 4 degrees C in the nutrient medium (TC-199, calf serum and HEPES buffer). The cryopreserved valves were frozen by a programmable freezer to -80 degrees C in the same nutrient medium containing 10% dimethylsulfoxide (DMSO), and subsequently stored in liquid nitrogen (-196 degrees C). We assessed the cell viability of the allograft valve leaflet, before storage and at 2 weeks, 1 month and 2 months after the storage. Suspensions of the valve leaflet fibroblasts were double-stained with FDA (1 micrograms/ml) and PI (1 microgram/ml) for flowcytometric analysis of the viable cells (cells showing a chromatic response to FDA but no response to PI). In the cold-preserved group, percentage of the viable cell was 90.3 +/- 3.6% before storage, 62.0 +/- 3.0% after 1 month of storage, and 50.3 +/- 3.7% after 2 months of storage.(ABSTRACT TRUNCATED AT 250 WORDS)

Aortic Valve↗
PubMed1992

Minimal functional size of porcine lung and testicular angiotensin-converting enzymes deduced from radiation inactivation analysis. Interaction of two highly homologous domains in somatic isoenzyme.

Domain structures of porcine lung and testicular angiotensin-converting enzymes (ACE) were studied by radiation inactivation to test the hypothesis that lung ACE has two catalytic sites localized to discrete, structurally independent domains (the N- and C-domains) of approximately equal size. The minimum functional sizes of lung and testicular ACE, calculated from the inactivation curves obtained, were 140 and 74 kDa, respectively. Since testicular ACE has been demonstrated to contain only the C domain, this result indicates that the two domains in lung ACE are not independent but are, in fact, structurally tightly linked.

Animals↗
PubMed1992

An analysis of proliferating cells in biopsy specimens from patients with small hepatocellular carcinoma.

The proliferation of neoplastic and nonneoplastic hepatocytes is caused by various humoral growth factors with autocrine and paracrine mechanisms, and the proliferative activity of both hepatocytes and nonhepatocytic cells contributes to neoplastic growth. The authors attempted to detect various kinds of proliferating cells immunohistochemically in small hepatocellular carcinoma (HCC) using a monoclonal antibody against DNA polymerase alpha. Most of the HCC cells that stained for this enzyme were small, had basophilic cytoplasm with poorly developed organelles, and aggregated to form clusters distributed randomly within cancer nests. Nonhepatocytic cells also were stained, including some endothelial cells, Kupffer's cells, macrophages, and lymphocytes. Fat-storing cells were not stained. The number of stained sinusoidal (capillary) cells decreased in this order: Kupffer's cells and macrophages, endothelial cells, and fat-storing cells. Nonhepatocytic cells, including lymphocytes, proliferated more actively in areas with actively growing HCC cells than in those with quiescent cancer cells. The relationship between stained HCC cells and stained sinusoidal cells was clearly defined; the correlation coefficient was 0.97. These findings suggest the possibility of a relationship between the proliferative activity of neoplastic hepatocytes and that of sinusoidal cells, including lymphocytes.

Aged↗
PubMed1992

In vitro release of glutamate and aspartate from zebra finch song control nuclei.

The release of glutamate and aspartate from a song control nucleus, the robust nucleus of the archistriatum (RA) of the zebra finch was examined in slice preparations. The RA received inputs from two other song control nuclei, the high vocal center (HVc) and the lateral magnocellular nucleus of the anterior neostriatum (1MAN). The fibers that innervated the RA from either the HVc or the 1MAN caused calcium-dependent release of glutamate and aspartate after electrical stimulation. It is likely that synapses of the RA from the HVc and the 1MAN utilize glutamate or aspartate as a neurotransmitter.

Animals↗
PubMed1992

Properties and localization of endothelin-1-specific receptors in rat testicles.

The characterization and localization of rat testicular endothelin receptors were studied. Receptor binding assay with radiolabeled members of the endothelin family revealed that endothelin-1-specific receptors were present in rat testes; a maximal binding capacity of 250 +/- 62 fmol/mg protein and a dissociation constant value of 0.35 +/- 0.06 nM were calculated from the Scatchard plot. The affinities for endothelin analogues were endothelin-1 = endothelin-2 much greater than endothelin-3 much greater big endothelin-1 for the membrane-bound receptors. Receptors of endothelin-1 were localized in peritubular myoid cells and interstitial cells of rat testis by 125I-labeled endothelin-1 autoradiography; the receptors were undetectable in spermatogenic cells. The presence of endothelin-1 receptors in the rat testis raises the possibility that one or more of the endothelins may play a physiological role in the regulation of testicular function.

Animals↗
PubMed1992

Hypertension in unilateral atrophic kidney secondary to ureteropelvic junction obstruction.

A patient with atrophic unilateral hydronephrosis due to ureteropelvic junction obstruction associated with hypertension was successfully treated by nephrectomy. Preoperatively, plasma renin activity was elevated in both the peripheral vein and affected renal vein. Renin concentration in the resected kidney was high, and immunohistochemical localization of renin was observed along the afferent arterioles of the juxtaglomerular apparatus and in arterioles at some distance from the glomeruli.

Adult↗