Search PubMed⌕ Search

Biomedical subjects

S Onishi

Publications and source records attributed to S Onishi.

At least 145 records · Page 8Linked to original sources
PubMed1995

Effect of calcium antagonist, nicardipine, on cerebral blood flow in postasphyxial newborn piglets.

An experiment was carried out in nine piglets within 24 h after birth (control group: four, nicardipine group: five) for the purpose of evaluating the effects of a calcium antagonist, nicardipine, on cerebral blood flow changes induced by asphyxia neonatorum. Under respiratory control with a mechanical ventilator, the animals were exposed to hypoxia. The inspiratory oxygen level was lowered at 15 min intervals from 0.08 to 0.06 and then to 0.05. When bradycardia (heart rate; 60/min or less) was observed, 100% oxygen, adrenaline, and sodium bicarbonate were administered for resuscitation. Nicardipine was administered at a dosage of 10 micrograms/kg via bolus injection 30 min after the resuscitation. It was administered thereafter at a rate of 10 micrograms/kg per h. The cerebral blood flow was measured using a laser Doppler velocimeter. The cerebral blood flow, electroencephalograph (EEG), blood pressure, and heart rate were continuously measured for 120 min after the resuscitation. In the control group, the mean arterial pressure 35 min after the resuscitation was 60 mmHg or more. However, the cerebral blood flow was lower than the prehypoxia value in the animals with a mean arterial pressure of 75 mmHg or less. In the nicardipine group, the mean arterial pressure was lower, but the cerebral blood flow was higher than the prehypoxia value and cerebral ischemia was not induced. The mean arterial pressure 120 min after the resuscitation was 72.0 +/- 8.2 mmHg in the control group, while it was 56.7 +/- 7.5 mmHg in the nicardipine group. It was significantly lower in the latter.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

Humoral and cellular immune responses to dihydrolipoamide dehydrogenase (E3): lack of specificity for primary biliary cirrhosis.

Immune responses to dihydrolipoamide dehydrogenase, the E3 subunit which is a common component of 2-oxoacid dehydrogenase complexes, have been suggested to be associated with the etiology of primary biliary cirrhosis (PBC). However, since an antibody to E3 could be detected in Caucasian patients with PBC, but was not specific for the disease, the proposal is not evident at the antibody level. We have identified the antibody also in Japanese patients with PBC by immunoblotting with sera at a 1:100 dilution and have assessed cellular immune responses to E3 by proliferation assay of peripheral blood lymphocytes. Anti-E3 antibody was detected more frequently in 25 of 43 PBC (58.1%) than in normal controls (p < 0.01) and in chronic liver diseases (p < 0.05), but the antibody was not specific for PBC as reported in Caucasian PBC. Anti-E3 antibody-positive sera of PBC patients or normal controls and their IgG fraction did not inhibit the enzyme activity of E3. Lymphocyte blastogenesis to E3 in PBC was significantly greater than normal controls (p < 0.05), but was not significant as compared with chronic liver disease or non-hepatic autoimmune diseases. Thus, these data do not support the hypothesis that the immune response to the E3 subunit is associated with etiology of PBC.

Autoantibodies↗
PubMed1995

The arterial ketone body ratio and serum alpha-fetoprotein level in patients with acute hepatic failure.

Hepatocyte regeneration is essential for recovery in acute hepatic failure, although it requires a large amount of energy. The ratio of acetoacetate to beta-hydroxybutyrate in arterial blood has been reported to reflect the cellular energy charge of hepatocytes, and we proposed that the recovery of the ratio in the early days of acute hepatic failure is essential for survival. However, there is no report on any marker of regeneration to confirm this hypothesis. In this study, we have assessed this ratio and the serum alpha-fetoprotein level sequentially in 26 patients with acute hepatic failure. Ten patients recovered and 16 died. The arterial blood ketone body ratio 3 days after the onset of hepatic encephalopathy of grade II or more was below 0.6 in 15 of the 16 nonsurvivors, whereas that in the 10 survivors was above 0.6. There was a positive correlation between the arterial blood ketone body ratio and the maximal concentration of alpha-fetoprotein (r = 0.465, p < 0.02 by Student's t-test). These data indicate that the arterial blood ketone body ratio is a marker for the capacity of the liver to regenerate and for the prognosis in patients with acute hepatic failure: effective hepatocyte regeneration may be impossible if these metabolic changes in acute hepatic failure impair the hepatocyte energy charge severely.

3-Hydroxybutyric Acid↗
PubMed1995

Assessment of training-induced autonomic adaptations in athletes with spectral analysis of cardiovascular variability signals.

The purpose of this study was to assess the adaptive effects of endurance training on autonomic functions in athletes with spectral analysis of cardiovascular variability signals. Continuous ECG, arterial blood pressure (ABP), and respiratory signals were recorded from 15 athletes (VO2max > 55 ml/(kg.min)) and 15 nonathletes (VO2max < 45 ml/(kg.min)) in the sitting position during controlled respiration (tidal volume 700 ml and 15 cycles/min). The autonomic functions were assessed by the normalized low-frequency power (LF power: 0.06-0.14 Hz) and high-frequency power (HF power: the region of the respiratory frequency based on respiratory spectrum) obtained from the autospectra of the RR interval, systolic arterial pressure (SAP), and diastolic arterial pressure (DAP) variability signals. The spontaneous baroreflex sensitivity (BRS) was evaluated by the moduli, BRSLF and BRSHF, of the transfer function between the RR interval and SAP variability in LF and HF bands. The resting HR in athletes was significantly lower than that in nonathletes. In the case of RR interval spectra, the HF power was significantly higher in athletes than in nonathletes, whereas the LF power was significantly lower in athletes than in nonahtletes. These differences might reflect an alteration of sympathovagal interaction with a predominance of parasympathetic activity. However, there was no significant difference in the LF power of SAP and DAP autospectra, reflecting the sympathetic vascular control. The BRSLF and BRSHF were significantly higher in athletes as compared with nonathletes. These results indicate that endurance training induces autonomic imbalance (i.e., the enhanced vagal activities/the attenuated sympathetic tone), which may in part contribute to the resting bradycardia and an increase in the spontaneous BRS in athletes.

Adaptation, Physiological↗
PubMed1995

Hepatic sinusoidal endothelial cells can store and metabolize serum immunoglobulin.

Sinusoidal inclusion-containing endothelial cells in the liver were investigated with particular interest in their capacity of metabolizing immunoglobulin. Formalin-fixed deparaffinized liver specimens were used for immunohistochemistry, and pronase digestion was proved to be effective for antigen retrieval of immunoglobulin. The inclusions in sinusoidal endothelial cells were strongly immunostained with anti-immunoglobulin (Ig)G, IgA, and IgM antibodies in predigested sections. The complements were not identified immunohistochemically in the inclusions even after pronase treatment. Two women with autoimmune liver disease, who initially represented high levels of serum gamma globulin and abundant inclusion-containing endothelial cells, were studied. The subsequent biopsy after effective corticosteroid therapy demonstrated significant histological improvement as well as the disappearance of inclusion-containing endothelial cells (ICECs). During and after treatment, their serum gamma globulin levels were drastically reduced. In conclusion, the hepatic sinusoidal endothelial cells can take up serum immunoglobulin, probably through a receptor-mediated pathway, and its excessive storage results in the formation of cytoplasmic inclusions that are easily recognized by a light microscope. The stored immunoglobulin may be degraded in the cytoplasm, and the inclusions would disappear in association with the reduction of sinusoidal gamma globulin content. In other words, the intralobular density of inclusion-containing endothelial cells is a morphological predictor for the serum gamma globulin level.

Adrenal Cortex Hormones↗
PubMed1994

Lupus anticoagulant autoantibody induces apoptosis in umbilical vein endothelial cells: involvement of annexin V.

The effects of lupus anticoagulant (LAC) on cultured human umbilical vein endothelial cells were studied. All five monoclonal antibodies from a patient with systemic lupus erythematosus (SLE), as well as plasma samples with LAC activity from six SLE patients, induced apoptosis. Anti-annexin V IgG also induced apoptosis. Since monoclonal antibodies and plasma from SLE patients had an affinity for annexin V, an endothelial apoptosis pathway mediated by annexin V was suggested as the molecular pathogenesis of the hemostatic derangement associated with LAC.

Animals↗
PubMed1994

Hitherto unrecognized arterioles within hepatocellular carcinoma.

The distribution of blood vessels in human hepatocellular carcinoma was studied with the anti-a-smooth muscle actin monoclonal antibody by light and electron microscopy, and with morphometric analysis. a-Smooth muscle actin-positive arterioles were never observed in lobules or pseudolobules of non-cancerous areas, but were frequently seen within hepatocellular carcinomas. Morphometric analysis revealed that most of these arterioles measured between 10 and 25 microns in diameter. The morphology of intratumoural arterioles differed considerably from that of conventional arteries in the portal tracts of the non-cancerous area. The presence of abundant intratumoural arterioles can explain the angiographic hypervascularity of hepatocellular carcinoma and provides a pathological basis for its susceptibility to hypoxia and for arterial embolization as a therapeutic strategy.

Adult↗
PubMed1994

Immunoelectron microscopic observations on Leu-7 positive cells in virus-related chronic liver diseases.

We investigated the liver biopsies of 78 patients with hepatitis virus-related chronic liver diseases (B type; 14 patients, C type; 64 patients) by immunoelectron microscopy with the Leu-7 monoclonal antibody in order to determine the association of NK/K cells in virus-related chronic liver diseases. Most Leu-7 positive cells in the liver had the Pit cell morphology but a few Pit cells were Leu-7 negative. A few Leu-7 positive cells had neither Pit cell nor typical T cell morphology. No ultrastructural difference was observed in Leu-7 positive cells between hepatitis B virus- and hepatitis C virus-related chronic liver diseases. Regardless of virus type and hepatitis activity, the fine morphology of extravascular Leu-7 positive cells differed considerably from intravascular cells. Leu-7 positive cells were regularly seen in the cellular infiltrates but the ratio of Leu-7 positive cells/whole infiltrates was low. There was no correlation between the inflammatory activity of the disease and the level of Leu-7 positive cell infiltration. A virus aetiology (hepatitis-C or hepatitis-B) did not affect Leu-7 positive cell infiltration. We conclude that NK cells play only a small role in the pathogenesis of hepatitis B virus or hepatitis C virus-related hepatocytolysis, during the chronic stage.

Adult↗
PubMed1994

Immunohistochemical identification of Ito cells and their myofibroblastic transformation in adult human liver.

To identify Ito cells in normal and pathological adult human livers, immunohistochemical studies were performed by the avidin-biotin-peroxidase complex method using monoclonal antibodies for alpha-smooth muscle actin (ASMA), desmin, and vimentin. Fifty one needle biopsies, 7 surgically resected specimens, and 5 autopsy specimens were studied. In the normal adult liver vascular smooth muscle cells and pericytes, together with perisinusoidal cells with thin cytoplasmic processes were positive for ASMA. These latter cells formed a loose and discontinuous layer along the sinusoidal walls. Immunoelectron microscopy showed that the ASMA-positive perisinusoidal cells were Ito cells containing fat droplets. The other sinusoidal lining cells were negative for ASMA. In chronic liver disease, ASMA-positive Ito cells showed an increase in number, size, and the intensity of immunostaining in areas of piece-meal necrosis), and formed a continuous cellular network. These cells were dendritic in shape with irregularly elongated cytoplasmic processes and contained an increased amount of microfilaments, in association with loss of the characteristic fat droplets. Thus, their ultrastructural features corresponded to those of myofibroblastic cells. Ito cells showed no staining for desmin in both normal and pathological livers. These results indicate that immunohistochemistry using an anti-ASMA antibody is a sensitive and reliable method for the identification of both normal and transformed Ito cells in adult human livers.

Actins↗
PubMed1994

Alpha-smooth muscle actin-positive perisinusoidal stromal cells in human hepatocellular carcinoma.

The purpose of this study is to clarify the morphological characteristics and functional significance of the perisinusoidal stromal cells in hepatocellular carcinoma. The liver specimens surgically resected from 24 patients with hepatocellular carcinoma were studied by electron microscopy and immunohistochemistry using monoclonal antibodies against alpha-smooth muscle actin, vimentin and desmin. In the tissue space between endothelial cells and trabeculae of cancer cells, the stromal cells were frequently found. They were strongly positive for alpha-smooth muscle actin, weakly and less frequently positive for vimentin but negative for desmin. They varied in shape, size and distribution, stretching cytoplasmic processes and occasionally surrounding the trabeculae of cancer cells. They contained considerable amounts of microfilaments that were positive for alpha-smooth muscle actin and condensed in cell periphery. Along the cell membrane, the short dense areas and pinocytotic vesicles were seen. The external lamina incompletely invested the stromal cells. They were always surrounded by amorphous material. In the granulation tissue and fibrotic areas around necrotic cancer tissue, they were increased in size and number. On the other hand, immunohistochemically and ultrastructurally, they closely resembled the Ito cells in the piecemeal necrosis that showed myofibroblastic transformation. These results suggest that the perisinusoidal stromal cells in nonnecrotic cancer tissue produce the extracellular matrix in the tissue space and maintain the cancerous trabecular structure. After necrosis of cancer tissue, they may become activated and actively participate in the fibrosis.

Actins↗
PubMed1994

Plasma exchange and the arterial blood ketone body ratio in patients with acute hepatic failure.

Hepatocyte regeneration in acute hepatic failure is essential for recovery, but requires a large amount of energy. One problem with plasma exchange as supportive therapy in these cases is that massive citrate infusion has an adverse effect on the hepatic energy charge, which may be a serious risk in these patients. The ratio of acetoacetate to beta-hydroxybutyrate in arterial blood has been reported to reflect the cellular energy charge of hepatocytes. In this study, this ratio was assessed before and after plasma exchange in 19 patients with acute hepatic failure. Eight patients recovered and 11 died. The arterial blood ketone body ratio was below 0.6 in all 11 nonsurvivors. It fell to below 0.4 in 10 of them during the first plasma exchange session, and remained below 0.4 for over 12 h in seven of them. On the other hand, the arterial blood ketone body ratio returned to above 0.6 in four of eight surviving patients within 12 h after the first plasma exchange and remained below 0.4 for over 12 h only in two of eight patients. These data indicate that plasma exchange may cause suppression of the arterial ketone body ratio in patients with severe acute hepatic failure. These metabolic changes impair liver metabolism and may make effective hepatocyte regeneration impossible.

3-Hydroxybutyric Acid↗
PubMed1994

DNA typing of HLA class II genes; DRB1*0803 increases the susceptibility of Japanese to primary biliary cirrhosis.

The association between human leukocyte antigens and primary biliary cirrhosis is controversial, but major histocompatibility complex class II antigen DR8 was recently reported to be associated with increased susceptibility for primary biliary cirrhosis in some Caucasians and Japanese. Accordingly, we performed DNA typing of HLA class II genes in Japanese patients with primary biliary cirrhosis. The genotypes of HLA DRB1, DRB3-5, DQA and DQB were determined by polymerase chain reaction and subsequent hybridization with sequence specific oligonucleotides in 31 primary biliary cirrhosis patients and 215 racially matched local controls. DR8 was found in 24 of the 31 primary biliary cirrhosis patients and was highly concentrated in DRB1*0803. The gene frequency of DRB1*0803 was significantly increased in the patients (35.5% vs 7.4%, relative risk = 6.84, p < 0.0001). DQA1*0103 and DQB1*0601 were also increased in the primary biliary cirrhosis patients, in relation to linkage disequilibrium with DRB1*0803 on the same haplotype. In contrast, DQA1*0102 showed a significantly lower frequency in the primary biliary cirrhosis patients (p < 0.05). These data suggest that DRB1*0803 is one of the HLA class II genes related to an increased risk of primary biliary cirrhosis in Japanese individuals.

Adult↗
PubMed1994

Composite gastric seromuscular and omental pedicle flap for urethral and scrotal reconstruction after Fournier's gangrene.

A new composite gastric seromuscular and omental pedicle flap is described that can provide immediate airtight or watertight closure in the repair of complex defects involving the urethra. This flap was used to repair defects of the urethra, scrotum, and abdominal wall in a patient with Fournier's gangrene. The seromuscular patch was sutured to the urethral defect, and the omentum was applied over the defects of the scrotum and abdominal wall. This new procedure made it possible to close the skin primarily without leakage or infection. The patient had an uncomplicated recovery. Postoperative urethrography demonstrated no leakage or stenosis.

Abdominal Muscles↗