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Biomedical subjects

S Kawano

Publications and source records attributed to S Kawano.

At least 307 records · Page 17Linked to original sources
PubMed1992

Computer-assisted two-dimensional analysis of gastric mucosal hemoglobin distribution using electronic endoscopy.

An electronic endoscope was modified to assess the imaging of two-dimensional distribution of gastrointestinal mucosal hemoglobin with the aid of a computer and image analyzing system. The band-pass filters ranging from 530-470 nm (G'), and 770-830 nm (IR) replaced ordinary filters in a conventional electronic endoscope (Olympus V-10 or EVIS-200). As the hemoglobin is the most abundant biological pigment in the gastrointestinal mucosa absorbing the green light with little absorption in the infrared region, we used the algorithm of 32 [log2(Vir/Vg)] as a reflection of hemoglobin content in the surface mucosa. The algorithm had a good correlation with the spectrophotometrically measured hemoglobin concentration. The mucosal distribution of hemoglobin was displayed in patients with gastric ulcer. In conclusion, the computer and image analyzing system were successfully applied in an attempt to determine gastric mucosal hemoglobin content and its distribution. The possible applications of computers in endoscopic image analysis are discussed.

Adult↗
PubMed1992

Interleukin-1 beta directly excites hypothalamic supraoptic neurons in rats in vitro.

Responses of 42 neurosecretory neurons in the supraoptic nucleus (SON) to human recombinant interleukin-1 beta (IL-1 beta) were examined during intracellular recordings in rat brain slices. IL-1 beta (10(-9)-10(-8) M) depolarized the membrane and caused increased firing in 25 neurons (59.5%). In 11 other neurons (26.6%), depolarization was also seen, followed by membrane hyperpolarization. The IL-induced depolarizing effect remained in the presence of tetrodotoxin (TTX) but was abolished by sodium salicylate. The results suggest that IL-1 beta mainly exerts a direct excitatory effect on SON neurons and further, that prostaglandins may be involved in such an effect.

Animals↗
PubMed1992

Portal vein aneurysm demonstrated by blood pool SPECT.

Portal vein aneurysms are rare and are occasionally suggested by ultrasound and usually confirmed by invasive angiography. Such a case was diagnosed by scintigraphic studies, most importantly blood pool SPECT, which clearly separates it from hepatic cysts.

Adult↗
PubMed1992

Conversion of proplastids to amyloplasts in tobacco cultured cells is accompanied by changes in the transcriptional activities of plastid genes.

When tobacco (Nicotiana tabacum L.) cultured cells (line BY-2) at the stationary phase were transferred to culture medium that contained cytokinin (benzyladenine) instead of auxin (2,4-dichlorophenoxyacetic acid), proplastids in the BY-2 cells were converted to amyloplasts within 48 h. The data obtained from in vitro transcription assays using isolated plastid-nucleoids (nuclei) strongly suggested that amyloplast formation in BY-2 cells was accompanied by changes in the transcriptional activities of plastid genes.

Journal Article↗
PubMed1992

Persistently high antibody titers and deficient specific cellular immunity to varicella-zoster virus in a retarded patient after varicella infection.

We report on a 19 month old female who has been retarded developmentally after a severe varicella infection contracted from her mother 4 months after delivery. Her titer of varicella-zoster virus (VZV) IgG antibody has been remarkably high for 4 years after the infection. Natural killer activity and the specific cellular immunity to VZV, as tested by delayed type hypersensitivity skin test and lymphocyte-proliferation assay, were impaired. She had an improvement of ataxia and then progressed developmentally after administration of an anti-viral agent. Administration of oral corticosteroids and methylprednisolone transiently decreased titers of VZV antibody and, contrary to previous reports, returned natural killer activity to normal levels. We suggest that this case may be a persistent VZV infection similar to congenital cytomegalovirus infection due to selective defects in cellular immunity including NK cells. Whether this specific deficient cellular immunity is genetically determined or secondary to the viral infection is speculative. This is the first known report of such a case.

Antibodies, Viral↗
PubMed1992

Ethanol stimulates immunoreactive endothelin-1 and -2 release from cultured human umbilical vein endothelial cells.

The present study employed enzyme-immunoassay to examine the effect of ethanol on endothelin-1 and/or -2(ET1 + 2) release from human umbilical vein endothelial cells. Thirty minutes of exposure to ethanol increased the release of immunoreactive ET1 + 2 from cultured endothelial cells in a dose-dependent manner. However, ethanol at concentrations of less than 400 mM did not induce any LDH release from the endothelial cells. Trypan blue exclusion test revealed that 400 mM solution of ethanol decreased the cell viability to 7.7%. Thus, ethanol was found to directly stimulate ET1 + 2 release from cultured human umbilical vein endothelial cells. This reaction of vascular endothelial cells against ethanol may be related to ethanol-induced cardiovascular diseases such as hypertension, myocardial infarction and stroke, as well as fatal alcohol syndrome.

Cells, Cultured↗
PubMed1992

The influence of argon laser panretinal photocoagulation on the rabbit ERG c-wave.

We observed the influence of panretinal photocoagulation on the ERG c-wave in rabbit eyes. DC-registered ERGs were recorded from rabbit eyes before and after photocoagulation, and compared with those of the fellow eyes. The rabbits were subdivided into 3 groups according to application numbers: 500, 1000, and 1500 spots. The ERG c-waves were found to have totally disappeared in all rabbits 3 days after panretinal photocoagulation, then reappeared with various intervals. In the 500 spot group, the c-wave reappeared after one week, and almost reached control levels in one and a half months. In the 1000 spot group, a 10 day delay was noted, and 90% of control levels were regained after 6 months. In the 1500 spot group, the c-wave didn't reappear until 2 weeks later, and regained 70% (of the control level) after 6 months. The recovery rates were related to the number of laser applications. These results indicate that the ultimate degree of recovery in c-wave amplitude and the time required for the reestablishment of retinal pigment epithelium function both depend on the size of the coagulated area.

Animals↗
PubMed1992

Effect of intravascular ethanol on modulation of gastric mucosal integrity: possible role of endothelin-1.

The influences of intravascular ethanol on gastric mucosal integrity and its relation to gastric circulation were investigated in rats. Ulcer formation of the gastric mucosa correlated with the blood ethanol concentration in the presence of 150 mM HCl in the rat stomach. Furthermore, the gastric mucosal hemoglobin concentration (IHb) and hemoglobin oxygen saturation (ISO2), estimated using organ reflectance spectrophotometry, decreased in a concentration-dependent manner with blood ethanol. In isolated, vascularly perfused rabbit stomach, various concentrations (10-400 mM) of ethanol infused into the celiac artery increased the perfusion pressure and released endothelin-1 (ET-1) from the gastric vasculature in a concentration-dependent manner. Moreover, a significant correlation existed between changes in the perfusion pressure and ET-1 concentration in effluents from the gastric vasculature. Furthermore, anti-ET-1 antibody reduced 100 mM ethanol-induced vasoconstriction in a concentration-dependent manner. The results indicate that intravascular ethanol increases the susceptibility of gastric mucosa to injury induced by intraluminal HCl by causing gastric vasoconstriction mediated by ET-1. Thus intravascular ethanol may play an important role in the mechanism of ethanol-induced gastric mucosal injury.

Animals↗
PubMed1992

Cardiac sarcoplasmic reticulum chloride channels regulated by protein kinase A.

In heart cells, several plasma membrane ion channels are targets for phosphorylation. However, it is not known whether sarcoplasmic reticulum (SR) ion channels, which are also essential in the regulation of cardiac function, are regulated by second-messenger systems. Here, we show that a Cl- channel in the cardiac SR membrane is activated by the catalytic subunit of protein kinase A (PKA). Purified cardiac heavy SR vesicles were incorporated into planar lipid bilayers. This channel spontaneously inactivated within a few minutes after the channel was incorporated into the bilayer. Mg-ATP (2-5 mM), but not the nonhydrolyzable ATP analogue 5'-adenylylimidodiphosphate, added to the cis solution prevented this spontaneous channel inactivation. After the inactivation process occurred, the catalytic subunit of PKA (with 0.05 mM Mg-ATP) reactivated this channel. These effects of Mg-ATP and PKA on the Cl- channel were prevented by an inhibitor of PKA. Thus, these results suggest that this SR Cl- channel is a novel target of PKA-dependent phosphorylation in cardiac muscle regulation.

Adenosine Triphosphate↗
PubMed1992

Cetraxate improves ethanol-induced gastric mucosal congestion in anesthetized dogs.

Gastric mucosal microcirculatory disturbance in experimental animals is stressed as an important factor in the development of gastric ulceration induced by ethanol. In this study, we used a reflectance spectrophotometry system to investigate the effect of cetraxate on ethanol-induced gastric mucosal hemodynamics in anesthetized dogs. Forty percent ethanol caused a significant increase in the mucosal blood volume and a significant decrease in mucosal hemoglobin oxygenation. The changes in these parameters indicated mucosal congestion and tissue hypoxia. Topical administration of cetraxate (200 mg in 10 ml saline) prevented the increase in mucosal blood volume and decrease in mucosal hemoglobin oxygenation which had been induced by ethanol loading in the stomach. In conclusion, cetraxate showed a protective effect on mucosal microcirculation that resulted in the maintenance of the gastric mucosal integrity against ethanol loading in the gastric mucosa.

Administration, Topical↗
PubMed1992

[Study of an outbreak of itai-itai disease].

We studied an outbreak of itai-itai disease in the Jinzu River basin, in Toyama, Japan. One hundred and fifty females recognized as itai-itai disease patients till by 1990 were studied for the ages and years of onset and residence in the cadmium-polluted area. 1. Cases were recognized from as early as 1929, increased gradually to the peak of 1955-1959 and rapidly decreased up to the 1970s. 2. It was found that the later the patients was born, the younger the age of onset, though there was no difference of ages of onset between the cases born in the 1910s and the cases born from 1920. 3. The onset of itai-itai disease was most frequently seen at 50-59 years of residence in the cadmium-polluted area. It was found that the later a person started to inhabit the cadmium-polluted area, the shorter the period of residence in the cadmium-polluted area up to onset of itai-itai disease. 4. Comparing the patients who inhabited the cadmium-polluted area from birth and those who had moved there from non-polluted areas, the age of onset was higher in the latter, but there were no significant differences in the period of residence up to onset. From these findings, it appeared that itai-itai disease was not caused by aging, but by cadmium exposure starting from the 1910s.

Cadmium Poisoning↗
PubMed1992

[[Comparison of mortality rates of elderly people in China and Japan]].

"The mortality rates and causes of death among elderly people aged sixty five and over were compared between China and Japan. The data used for comparison was China's 1990 and Japan's 1990 vital statistics. It appears that the mortality rate in China was higher than Japan. Comparing the causes of death, it was found that the death rates involving cerebrovascular diseases, malignant neoplasms and heart diseases in urban districts of China [were] higher than those in Japan. Also the death rate of people with bronchitis in rural districts was significantly higher in China.... The differences in the medical systems and life styles in China and Japan were suspected as the reasons for the differences of death rates and causes of death...." (SUMMARY IN ENG)

Adult↗
PubMed1992

[Protective effect of proton pump inhibitor on the gastric mucosa].

Although many authors reported that proton pump inhibitor showed mucosal protective activity, the precise mechanism is still unclear. In this study, we investigated the effect of proton pump inhibit on gastric mucosal hemodynamics, using a reflectance spectrophotometry system. The proton pump inhibitors had no effect on the gastric mucosal hemodynamics prior to the state of hemorrhagic shock state. However, during the hemorrhagic shock, proton pump inhibitors significantly inhibited the decrease in tissue oxygenation and significantly reduced ulcer formation. In conclusion, proton pump inhibitors maintained tissue oxygenation resulting in reduction of ulcer formation.

Adenosine Triphosphatases↗
PubMed1992

Detection of Epstein-Barr virus genome in natural-killer-like cell line, YT.

YT cells, originally reported as a natural-killer-like (NK-like) lymphoid cell line, were investigated for Epstein-Barr virus (EBV) genome, gene rearrangement for T-cell receptor (TCR), phenotype and function. The YT cells of the original batch (YT-0) and two subclones (YT2C2 and YTC3) expressed EBV-associated nuclear antigen, and the BamHI-digested DNA showed the 3.4 kb hybridizing band with the BamHIW probe of EBV DNA in Southern blot analysis. When tested with latent-infection membrane protein probe, an identical hybridizing band was shared, indicating that all three sources of YT cells were of monoclonal derivation in terms of the terminal repeat junctional structure of EBV DNA, and that the original YT cells had been infected with EBV before the isolation of the two subclones. The cell-surface antigen analysis revealed the expression of CD7, CD28, CD30, CD45R0, TLiSA and S6F1 antigen besides the originally recorded CD25, CD56 and HLA-DR antigen. Gene rearrangement analysis showed the germ-line genotype, including TCR gamma and delta as well as beta chain. The Northern blot study using the CD3 epsilon and CD3 delta chain gene probes revealed CD3 epsilon, but not CD3 delta RNA. The YT-0 cells exhibited NK and antibody-dependent cellular cytotoxicity activity, but the YT2C2 and YTC3 cells did not. It was not resolved whether the fresh neoplastic NK-like cells of the YT-cell donor carry EBV genome, but YT cells, the first lymphoid cell line found to have EBV genome and non-B lymphoid properties, are valuable for investigating the relationship between EBV and human non-B lymphoid hematopoietic cells.

Antigens, Surface↗
PubMed1992

[Fundamental studies of hepatitis C virus: a review].

In 1974, Prince et al. reported the existence of posttransfusion hepatitis with a long incubation period which was not related to hepatitis B virus (HBV). These cases were named "non-A, non-B" (NANB) hepatitis. The genome of NANB hepatitis virus was discovered recently using a recombinant complementary DNA (cDNA) approach. It was termed the hepatitis C virus (HCV), and a specific diagnostic tool for the circulating HCV antibody (anti-HCV) was developed using a purified viral polypeptide derived from recombinant yeast expressing a small part of the HCV genome. HCV is believed to be the main cause of blood-borne non-A, non-B hepatitis worldwide, which frequently evolves to chronic hepatitis and cirrhosis, and which may also be involved in the development of hepatocellular carcinoma. HCV is classified as part of the flaviviridae family and contains a positive-stranded RNA molecule by approximately 10 kb nucleotides. The HCV genome encodes a large polyprotein precursor, which is processed in structural nucleocapsid and envelope proteins and in non-structural proteins (NS1-NS5). Nucleotide sequence comparisons of distinct HCV isolates have shown a significant genetic variability between the different HCV strains. At present the diagnosis of HCV infection depends on various anti-HCV tests including second generation HCV Ab. Antigenic markers for HCV are being developed but the concentrations of HCV antigens in serum are at the lower limit of detectability by existing immunoassay technology. A polymerase chain reaction has been used to detect HCV RNA in the serum and liver. Serum HCV RNA disappears from serum after effective IFN treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Genes, Viral↗
PubMed1992

[Suppression of myeloperoxidase gene expression by gamma-interferon].

The gene expression of myeloperoxidase (MPO) in HL60 cells, as tested by Northern blot analysis with a MPO gene probe, was markedly suppressed by treatment with gamma interferon (IFN-gamma)(200U/ml) for 9hr, whereas cytochemically detected MPO activity, cell surface antigen expression, and cell morphology remained unchanged even at 48hr after the treatment. IFN-gamma of 50U/ml was sufficient for the suppression at 24hr. When the HL60 cells treated with IFN-gamma (200U/ml) for 24hr were cultured in the absence of IFN-gamma for another 24hr, the transcript of MPO gene reverted to a level comparable to that of the HL60 cells cultured thoroughly in the absence of IFN-gamma, indicating the reversibility of the suppression. The suppression of MPO expression at RNA level, possibly independent of differentiation, is one of the biological activities exerted by IFN-gamma, which has not been previously reported.

Actins↗
PubMed1992

[Proton pump inhibitors: their merits and demerits, and perspectives for future investigation].

Proton pump inhibitors have a potent antisecretory activity and are under development in many pharmaceutical companies. In this paper, the merits and demerits of the drugs, which have been revealed by experimental studies in humans and animals, are reviewed. Issues of the drugs which remain to be examined in the future are also discussed in reletion to their application in peptic ulcer patients. The issues include 1) genotoxicity of the drugs with long-term treatment; 2) their possible contribution to defensive factors of gastro-intestinal mucosa; 3) their antimicrobial activity against Helicobacter pylori; 4) interaction with the other drugs; etc.

2-Pyridinylmethylsulfinylbenzimidazoles↗