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Biomedical subjects

J Sato

Publications and source records attributed to J Sato.

At least 379 records · Page 21Linked to original sources
PubMed1987

Capillary hemangioblastoma: histogenesis of stromal cells.

The histogenesis of stromal cells in capillary hemangioblastoma has been the subject of debate. The light and electron microscopic studies of hemangioblastomas presented here showed pericytic and leiomyoblastic features in stromal cells. Cells cultured by the monolayer method showed similar features to those of the original tumors. Immunohistochemical studies for glial fibrillary acidic protein and factor VIII/von Willebrand factor indicated that stromal cells were antigenically distinct from astrocytes and endothelial cells. These findings suggest that stromal cells are closely related to pericytes and smooth muscle cells, and support Rhodin's speculation that pericytes serve as a precursor to smooth muscle cells.

Cells, Cultured↗
PubMed1987

Erythropoietin in haemangioblastoma: immunohistochemical and electron microscopy studies.

Immunohistochemical studies for erythropoietin were carried out in six capillary haemangioblastomas, three of which were also studied by electron microscopy. The immunohistochemical studies showed that positively stained cells were scattered in the vicinity of capillaries, and that neither endothelial cells nor stromal cells were stained. In their morphology and distribution, the positively stained cells were identical to mast cells as observed by electron microscopy. In one case, erythropoietin was demonstrated in the cyst fluid of the tumour. These findings suggest that mast cells with abundant secreting granules in haemangioblastomas are capable of producing erythropoietin.

Adult↗
PubMed1987

Effect of various barbituric acid derivatives on survival of functional hepatocytes from adult rats in primary culture.

Eighteen barbituric acid (BA) derivatives and three structurally related chemicals (non-BA-derivatives) were tested for their potency in supporting survival of functional hepatocytes from adult rats in primary culture. Of the 18 BA derivatives, nine drugs showed excellent maintenance effect on hepatocyte survival and function. Although four BA derivatives were also effective, their potency was relatively lower. The remaining five BA derivatives and three structurally related chemicals exhibited no maintenance effect. Thus, a correlation was found between the BA derivative structure and the potency for supporting hepatocyte survival in primary culture. The dose response curves of hepatocyte survival were generally biphasic in shape, as a function of BA derivative concentration. The optimum concentrations for observing the morphological and biochemical effects of the BA derivatives differed from each other. The maintenance of hepatocytes was attained only in the continuous presence of the BA derivatives in the medium. The nine excellent BA derivatives efficiently prevented hepatocytes from morphological degeneration which was observed in the control cultures. The surviving hepatocytes in the presence of these BA derivatives showed higher albumin secretion and retained higher basal levels of tyrosine aminotransferase (TAT) activity for at least 2 weeks in primary culture, as compared with control. Furthermore, the addition of dexamethasone (10 microM) caused a 2- to 4-fold induction of TAT activity for at least 2-weeks in primary culture.

Albumins↗
PubMed1987

Production of albumin and alpha-fetoprotein in primary culture of fetal human liver cells on collagenous substrata in the presence of hydrocortisone.

When primary cultures of fetal human liver cells established on type I collagen gels were compared to sister cultures developed on tissue culture plastic, the cells in contact with type I collagen secreted albumin at a higher rate than those without contact. The albumin secretion was dependent on the presence of hydrocortisone (HC) in the medium. Also, alpha-fetoprotein (AFP), of which the level decreased gradually and became undetectable after 6 d regardless of the presence or absence of HC in the cells cultured on plastic, was maintained for longer periods of time by plating the cells on type I collagen gels in the presence of HC. Different secretion rates of albumin and AFP were observed after Day 13 and Day 16, respectively, between cells maintained on type I collagen gels and those on film plastic. The cells secreted larger amounts of both albumin and AFP in plates coated with type IV or I collagens than with fibronectin after Day 10. The cells cultured on type I collagen gels were cuboidal in shape, whereas those on plastic were flattened in cultures with HC. These data indicate that the secretion of human albumin and AFP is facilitated by synergies between HC and collagenous substrata.

Albumins↗
PubMed1987

Synthesis of barbituric acid derivatives and their effect on survival of functional hepatocytes from adult rats in primary culture.

Ten barbituric acid (BA) derivatives were synthesized and tested for their potency for supporting survival of functional hepatocytes from adult rats in primary culture. Of the 10 BA derivatives, 7 compounds (C-2, 3, 4, 5, 6, 9, and 10) efficiently supported hepatocyte survival for at least 2 wks in primary culture. Especially C-5, 6, and 9 showed excellent efficiency for such action. The optimum concentrations of the BA derivatives for observing the morphological and biochemical effects differed from each other. The maintenance of hepatocytes was attained only in the continuous presence of the BA derivatives in the medium. The morphologic features of hepatocytes surviving in the presence of the BA derivatives resembled those of hepatocytes 24 h after inoculation. The surviving hepatocytes secreted remarkably large amounts of albumin into the culture media. Tyrosine aminotransferase (TAT) activity was higher in the 1-wk-old cultures treated with C-5, 6, and 9 than in the freshly isolated hepatocytes. The addition of dexamethasone (10 microM) caused a 1.7 to 2.1-fold induction in TAT activity. The basal levels of TAT activity and the induction rates increased in the cultures treated with C-5 and 6 from Week 1 to 2 of primary culture.

Albumins↗
PubMed1987

Dietary regulation of aldolase isozyme expression in rat intestinal mucosa.

Changes of aldolase A and B protein levels and their mRNA levels due to starvation for 48 h in mucosae of the jejunum, ileum, and colon were determined by Western and Northern blot analyses. In fed rats, B protein and B mRNA were predominant in the jejunum. In the ileum, both A protein and A mRNA, as much as B protein and B mRNA, were present in significant amounts. In the colon, A protein and A mRNA were predominant. The enzyme activity levels in those segments of fed rat intestine were in parallel to total enzyme protein levels (A + B) and also to total mRNA levels (A + B), thus suggesting that aldolase isozyme expression in fed rat intestine is determined mainly at the level of transcription. Starvation for 48 h caused about 30% reduction of both B protein level and B mRNA level in jejunum. In the ileum, both A and B mRNA levels were lowered 30-40% from those of fed rats, while A and B protein levels were reduced slightly (A, 0%; B, 12%). In the colon, starvation caused about 50% increase of A mRNA level and about 10% reduction of A protein level. By measuring the synthetic rate of the enzyme proteins from in vivo [35S]methionine incorporation, the accumulation of A mRNA in this tissue was suggested to be due to the significant fall of the translation rate of A mRNA. The translational and post-translational controls of aldolase isozyme expressions in rat intestines are discussed.

Animals↗
PubMed1987

Astrocytic characteristics of oligodendroglioma. Fine structural and immunohistochemical studies of two cases.

Two oligodendrogliomas were studied by light and electron microscopy. Additionally, an immunohistochemical study for glial fibrillary acidic protein (GFAP) was carried out. Some tumor cells exhibited glial filaments and perivascular end-feet, as on the one hand is characteristic of astrocytes, and glycogen granules and zonulae adherents which on the other hand are often seen in astrocytes but rarely in oligodendrocytes. Tumor cells with or without astrocytic characteristics showed the common fine structures and appeared to be on the same cell line. Our fine structural and immunohistochemical findings suggest that oligodendroglioma cells are of an astrocytic nature.

Brain Neoplasms↗
PubMed1987

Thermally potentiated responses to algesic substances of visceral nociceptors.

Using spermatic nerve preparations from testis superior, the effects of temperature rise on chemical responses were studied in vitro, within both subthreshold and suprathreshold ranges for testicular polymodal receptors, one type of visceral nociceptor. In the range of temperature subthreshold for polymodal receptors, the responses to algesic substances tested were greater at higher temperatures. The mean discharge rates induced by various concentrations of bradykinin (BK, 9 X 10(-9)-9 X 10(-6) M), were significantly greater at 36 degrees C than at 30 degrees C. Responses to hypertonic saline, tested in the temperature range, 34-43 degrees C, showed similar temperature-dependent increases, and Q10 values between 2.3 and 4.2. In the units exhibiting 'heat sensitization' with repeated testing of suprathreshold temperature rises, the response to hypertonic saline (616 mM) at 34 degrees C also increased. Although calor in the inflamed tissues is in itself not high enough to cause excitation of 'pain receptors,' temperature-dependent augmentation of chemical responses of the polymodal receptor might partly explain peripheral hyperalgesic behaviour observable in inflamed tissue on the basis of sensory receptor activity.

Animals↗
PubMed1987

Effects of salbutamol and hyperventilation on the rise in serum potassium after succinylcholine administration.

It is known that circulating catecholamines stimulating beta 2-receptors and the acid-base balance play important roles in the regulation of serum potassium (K+). The present study was undertaken to investigate the effect of salbutamol (SB), a highly selective beta 2 agonist, and hyperventilation (HV)-induced alkalosis on the change in serum K+ after succinylcholine (SCh) administration in dogs. Pretreatment with SB (0.4 microgram.kg-1.min-1 for 30 min) produced sustained decreases in serum K+ and mean arterial pressure, and transient increases in cardiac output and serum insulin concentration. Maintaining respiratory alkalosis with HV (PaCO2 = 2.6-3.3 kPa) produced sustained decreases in serum K+ and cardiac output. Although both pretreatment with SB and HV-induced alkalosis significantly reduced the absolute increases in serum K+ after SCh, the effect of SB was more remarkable than that of HV. These results suggest that the degree of beta 2-receptor activity can strongly modulate the change in serum K+ after SCh administration.

Albuterol↗
PubMed1987

Response properties of polymodal receptors studied using in vitro testis superior spermatic nerve preparations of dogs.

Characteristics of the polymodal receptor were studied using in vitro testis superior spermatic nerve preparations excised from anesthetized dogs. They were in most aspects similar to those reported previously using in vivo preparations. The majority (90%) of the tested polymodal units had small myelinated nerve fibers; the rest had nonmyelinated fibers. The mean mechanical threshold as determined by von Frey hairs was 17.5 g/mm2 (n = 476). There was a tendency for a unit with a higher conduction velocity to have a lower mechanical threshold. Bradykinin and hypertonic saline consistently caused a dose-dependent increase in discharge rate of these units; high K+ solution was also found to be a consistent stimulant. The responses of C-fiber receptors were not significantly different from those of A-delta-fibers. Heat stimulation up to 50 degrees C evoked discharges in 99 out of the total 103 units tested. The mean threshold temperature was 44.4 degrees C for the first trial. In 19 units in which the same heat stimulation was tested after an interval of 10 min, 10 units showed sensitization; 3 units were deactivated; and no clear difference was observed in the rest. No unit responded with a substantial increase in discharge rate to cold stimuli of 20 degrees C or less. A small temperature rise of 2 degrees C from the normal surface temperature of the testis (34 degrees C) significantly increased the response to hypertonic saline (616 mM) (2.41 +/- 0.22 impulses/s at 34 degrees C to 3.23 +/- 0.44 impulses/s at 36 degrees C) and to bradykinin (9 X 10(-8) M) (1.95 +/- 0.35 impulses/s at 34 degrees C to 2.85 +/- 0.19 impulses/s at 36 degrees C). The majority of the units recorded from the superior spermatic nerve in this experiment were most probably of polymodal receptor type, although the heat response was tested in a limited number of units. A very small number of a different type of receptor was discovered: rapidly adapting mechano-receptors, which responded almost exclusively to mechanical stimulation and were especially sensitive to a light mechanical stimulus moving across the receptive fields. The response properties of receptors studied in vitro remained practically unchanged during the experiments of several hours. The present experiments have shown that this preparation is suitable for systematic investigations, especially of the effects of chemical agents, on the polymodal receptor, which plays important roles in nociceptive functions.

Adaptation, Physiological↗
PubMed1987

Novel cholinesterase expression in the HuH-7 cell line.

On polyacrylamide gradient gel electrophoresis, normal serum cholinesterase was separated into seven isozymes (I-VII from the anodic to the cathodic side). The enzyme of the conditioned medium of the HuH-7 cell line, established from a human hepatoma, had two main isozymes. The one migrating faster was located slightly to the cathodic side of band II of the normal serum enzyme, and the other, a slower one, electrophoresed at the same position as that of band VI of the normal serum enzyme. Aside from these two isozymes, a faint band with enzyme activity sometimes appeared at a position just cathodic or very close to the position of band I of the normal serum isozymes. The effect of some inhibitors and activators on both the normal serum enzyme and the enzyme of the conditioned medium was similar, but lectin-binding properties of the two enzymes were different with Ricinus communis agglutinin I, concanavalin A and wheat germ agglutinin. These results suggest that the difference in sugar moieties of both enzymes is expressed in D-galactose, D-mannose and N-acetylglucosamine.

Carcinoma, Hepatocellular↗
PubMed1987

Immunochemically detected nuclear envelope-associated cytochrome P-450 component(s) in rat hepatocyte culture lines.

The presence and location of cytochrome P-450 in Donryu rat hepatocyte culture lines, Ac2F cells and 3 other cell lines were assessed by indirect immunofluorescence examination using anti-cytochrome P-450 monoclonal antibodies. Ac2F cells and other hepatocyte cell lines were selectively stained at their nuclear envelope, but not the cytoplasm, with a monoclonal antibody selective to a high-spin form of cytochrome P-448 (P-448H), although this monoclonal antibody stained primary cultured normal rat hepatocytes at both cellular components and did not stain hepatoma cells of 2 transplantation lines. The results of unscheduled DNA synthesis assay with Ac2F cells using several carcinogenic aromatic amines (4-aminoazobenzene derivatives and amino acid pyrolysis products) suggested that this nuclear envelope-associated cytochrome P-450 activates a restricted portion of these aromatic amines, i.e., a tryptophan pyrolysis component and a glutamic acid pyrolysis component. These results indicate that rat hepatocyte culture lines lack (or contain a reduced amount of) the cytoplasmic cytochrome P-450 but maintain a characteristic type of cytochrome P-450, probably a kind of cytochrome P-448H in their nuclear envelope, and this may be involved in oxidative metabolism of a restricted portion of aromatic amines.

Animals↗