Biomedical subjects

S Kawano

Publications and source records attributed to S Kawano.

At least 235 records · Page 13Linked to original sources

PubMed1994

Complex terminal structure of a linear mitochondrial plasmid from Physarum polycephalum: three terminal inverted repeats and an ORF encoding DNA polymerase.

The mitochondria of Physarum polycephalum have a linear plasmid (mF) which promotes mitochondrial fusion. To determine the terminal structure of the mF plasmid, restriction fragments derived from its ends were cloned and sequenced. The sequences showed that the mF plasmid has three kinds of terminal inverted repeats (TIRs). The most characteristic feature is a 144-bp repeating unit which exists between a 205-bp TIR at the extreme ends of the plasmid and another 591-bp TIR. All of the clones showed at least one of these 144-bp repeating units. The GC content of the 205-bp TIR (49%) was higher than those of the other TIRs and of another sequenced region (23%). This TIR can form three thermodynamically-stable hairpin structures based on complex internal palindromic components. Moreover, in the right terminal region of the mF plasmid, there is an open reading frame (ORF) which covers the entire 591-bp TIR and most of one of the 144-bp repeating units. This ORF encodes a 547-amino-acid polypeptide, ORF-547, and shows extensive homology with the polymerization domain of the putative DNA polymerases of linear mitochondrial plasmids from other sources.

Amino Acid Sequence↗

PubMed1994

IgM and IgA antibodies generated against hepatitis C virus core antigen in patients with acute and chronic HCV infection.

Antibody subclasses directed against the core protein (HCc) of hepatitis C virus (HCV) were measured in 27 patients with acute non-A, non-B (NANB) hepatitis, and 99 patients with chronic HCV-associated liver disease. IgM, IgA, and IgG anti-HCc responses were observed in 11 (40.7%), 7 (25.9%), and 18 (67%) patients with acute NANB hepatitis, respectively. Twenty-four (24.2%) and 40 (40.4%) patients with chronic HCV infection also had detectable IgM and IgA, respectively. IgM anti-HCc inconsistently detected acute infection, and HCV ribonucleic acid (RNA) could be detected preceding the rise in anti-HCc antibodies in five consecutive patients with acute hepatitis. IgM anti-HCc also could not distinguish acute from chronic infection and did not correlate with histologic progression. However, the form of IgA present (polymeric vs monomeric) did discriminate acute from chronic infection and the IgA anti-HCc titer correlated with histologic evidence of liver disease in patients with chronic HCV infection.

Acute Disease↗

PubMed1994

Impaired gastric mucosal energy metabolism in congestive gastropathy in cirrhotic patients.

To clarify the characteristics of congestive gastropathy, we investigated gastric mucosal hemodynamics and energy metabolism in cirrhotic patients, using a reflectance spectrophotometry system and high performance liquid chromatography. The index of the gastric mucosal blood volume of cirrhotic patients with esophageal varices was significantly higher, and the index of gastric mucosal blood oxygenation significantly lower, than those in controls, thus indicating congestion and hypoxia in the gastric mucosa. Energy charge levels in the gastric mucosa of cirrhotic patients with esophageal varices were also significantly decreased. The energy charge level showed a strong linear correlation with the index of mucosal blood oxygenation in the antral (r = 0.996, P < 0.01) and body (r = 0.994, P < 0.01) mucosa of the stomach. These findings suggest that congestive gastropathy in a portal hypertensive state causes hypoxia in the gastric mucosa, leading to a mucosal energy deficit that may increase mucosal susceptibility to aggressive factors.

Chromatography, High Pressure Liquid↗

PubMed1994

Role of endothelin 1 in hemorrhagic shock-induced gastric mucosal injury in rats.

BACKGROUND/AIMS: Gastric microcirculatory disturbances are involved in the pathogenesis of stress ulcers; however, vasomodulators regulating this process are not fully understood. This study was conducted to investigate the role of endothelin 1 (ET-1) in hemorrhagic shock-induced gastric mucosal damage in rats. METHODS: ET-1 contents in plasma and gastric mucosa were measured and gastric mucosal damage was evaluated during a control period, 60 minutes of ischemia, 15 minutes of reperfusion, and 30 minutes of postreperfusion. Next, effects of BQ-123, an endothelinA receptor antagonist, on the gastric mucosal damage and hemodynamics were studied. RESULTS: Both plasma and mucosal ET-1 significantly increased after ischemia and reperfusion compared with the control values, but only mucosal ET-1 continued to increase after reperfusion, leading to the development of gastric mucosal damage. BQ-123, administered just before reperfusion, reduced mucosal damage in the postreperfusion period dose-dependently and improved mean gastric mucosal blood flow and mucosal hemoglobin oxygen saturation during the 30-minute postreperfusion period. CONCLUSIONS: These results suggest that endogenous ET-1 plays an important role in the pathogenesis of hemorrhage shock-induced gastric mucosal damage through impairment of mucosal microcirculation. Further, endothelinA antagonists may have therapeutic benefits for shock-induced gastric mucosal damage.

Animals↗

PubMed1994

Vasoactive effect of endothelin-1 on rat liver in vivo.

The purpose of this study was to evaluate the role of endothelin-1 in modulating hepatic microcirculation and liver damage. Rats were infused with endothelin-1 at doses ranging from 30 to 1,000 pmol/kg over 1 min through an indwelling cannula placed in the portal vein. In control rats, saline solution was infused at the same rate. Alterations in hepatic microcirculation were measured with an in vivo microscopy system. Serum lactate dehydrogenase activity, an indicator of hepatic damage, was measured 1 hr after endothelin-1 infusion. Immediately after infusion of endothelin-1, we noted a rapid increase in portal pressure, which remained increased for up to 30 min after endothelin-1 infusion. In contrast, systemic blood pressure remained unchanged, even at 1,000 pmol/kg of endothelin-1. Sinusoidal width was reduced and sinusoidal erythrocyte velocity was diminished in a dose-dependent manner. Oxygen saturation of blood in sinusoids was decreased in a dose-dependent manner, reaching values around 40% of control with 1,000 pmol/kg endothelin-1. The degree of decrease in oxygen saturation of blood in sinusoids had an excellent correlation with the calculated blood flow in the liver tissue. Serum lactate dehydrogenase levels were three to four times control values when endothelin-1 was administered at 1,000 pmol/kg. Thus endothelin-1 decreased hepatic tissue oxygenation associated with sinusoidal vasoconstriction. At high concentrations of endothelin-1, this decrease results in hepatocellular damage.

Animals↗

PubMed1994

Coinfection of hepatitis C virus in patients with chronic hepatitis B infection.

Enzyme-linked immunosorbent assays for detecting antibodies against hepatitis C virus and the polymerase chain reaction were tested in 82 chronic hepatitis B surface antigen carriers for their accuracy in diagnosing patients coinfected with hepatitis B and C viruses. To clarify the role of each virus in chronic hepatitis, serologic assays against hepatitis B virus were also tested. Thirteen (14.9%), 14 (17.1%) and 15 (18.3%) patients were anti-HCV positive using C100 (HCV1), JCC, and a second generation test (HCV2), respectively. HCV RNA was detected by polymerase chain reaction in 9 of 18 anti-HCV-positive cases. Although HCV1 assays were not sufficient, either the JCC or HCV2 assay detected all polymerase chain reaction-positive cases. Fifteen of 18 specimens that were positive in at least one of the three ELISA were seronegative for the hepatitis B e antigen. As judged by HBV DNA polymerase activity, titers of hepatitis B surface antigen and immunoglobulin A antibody against hepatitis B core antigen (IgA anti-HBc), activity of hepatitis B virus replication and immune response against hepatitis B virus in patients with coinfection was decreased to the level of hepatitis B virus asymptomatic carriers. These results show that hepatitis C virus appears to be the primary cause of active hepatitis in most patients with hepatitis B and hepatitis C virus coinfection.

Adolescent↗

PubMed1994

Gastroenterology.

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Gastroenterology↗

PubMed1994

Identification and diameter assessment of gastric submucosal vessels using infrared electronic endoscopy.

In this study, an electronic endoscope was applied for observation of gastric submucosal vessels, with infrared illumination, in anesthetized dogs. An in-vivo spectrophotometry showed that infrared light at 620-820 nm penetrates the abdominal and gastric wall. During the endoscopy performed in dogs, the infrared radiation penetrated the abdominal wall and gastric wall from the outside, and was detected by the endoscope's charge-coupled device. A television monitor displayed a network of gastric vasculature, which was identified as veins in the gastric wall by injecting saline or indocyanine green into the vein. Using this system, it was possible to measure venous diameters of more than 0.2 mm by comparison with a reference wire. The diameter obtained by the image analysis correlated lineally to that of a vascular template prepared from the same stomach. Thus, it may become possible to assess gastric submucosal hemodynamics using infrared endoscopy, a new application in electronic endoscopy.

Abdominal Muscles↗

PubMed1994

Varicella-zoster virus (VZV) reactivation is related to the low response of VZV-specific immunity after chickenpox in infancy.

To clarify the cause of herpes zoster in immunocompetent children, specific humoral and cellular immunity was determined using an ELISA and a lymphoproliferative assay, respectively, in infants < 1 year of age and children > or = 1 year of age who had chickenpox. Thirteen (59.1%) of 22 infants, 17 (81.0%) of 21 children > or = 1 year of age (P < .02), and 13 (86.7%) of 15 children > or = 2 years of age (P < .001) had positive varicella-zoster virus (VZV)-specific cellular immunity. VZV-specific antibodies in infants were significantly lower than those in children > or = 1 year old (P < .01) and > or = 2 years old (P < .001). The possibility of subclinical reactivation was demonstrated by an increase in the specific cellular or humoral immunity (or both) in all of 6 infants who had negative specific cellular immunity. The low response of specific immunity and the immunologic evidence of reactivation in infants after chickenpox provide a possible explanation for the finding that chickenpox in infancy is a risk factor for herpes zoster.

Antibody Formation↗

PubMed1994

Endothelin-1 is involved in hepatic sinusoidal vasoconstriction after ischemia and reperfusion.

Endothelin-1 (ET-1), a vasoactive peptide, causes a significant rise in portal vein pressure, which is most likely a result of severe vasoconstriction in the liver. In this study, the effect of ET-1 on sinusoidal vasoconstriction in the liver after ischemia and reperfusion was directly investigated using intravital microscopy. In anesthetized female Sprague Dawley rats (200-250 g) ischemia of the median and left liver lobes was induced for 90 min by temporary ligation of the left pedicle. After declamping and a 90-min reperfusion period, the livers were exposed for intravital microscopy. Using a Nikon MM-11 fluorescence microscope (545 nm, 330x), a CCD camera (Cohu FK 6990), and a SVHS video recording unit, the hepatic microcirculation was directly investigated. Besides sham groups, two ischemia groups were studied, receiving ET-1 antiserum (anti-ET-1; 0.5 ml; Peptide Inst., Osaka, Japan) or NaCl 0.9% (0.5 ml) 5 min prior to reperfusion of the liver (n = 6/group). Following a transient drop in the mean arterial blood pressure in the anti-ET-1-treated groups, comparable systemic hemodynamic conditions among the four groups were noted during intravital microscopic assessment at the end of the 90-min reperfusion period. Reduction in the sinusoidal diameters during postischemic reperfusion (7.7 +/- 0.5 microm) was prevented by anti-ET-1 treatment (9.6 +/- 0.25 microm; P < 0.01; mean + SEM) back to control values (9.6 +/- 0.32 microm), while most of other microcirculatory parameters did not show significant differences. The results supported further the role of ET-1 in dysregulation of the sinusoidal vascular tone in the liver, e.g., after ischemia and reperfusion.

Animals↗

PubMed1994

[Three interesting pediatric cases with penicillin-resistant Streptococcus pneumoniae infection].

Since penicillin-resistant Streptococcus pneumoniae first recognized in 1967, the rate of penicillin-resistant strains has been increasing worldwide. There have been up to 50% from pediatric specimens in Japan. We reported three pediatric cases with penicillin G resistant Streptococcus pneumoniae infection to show some important clue from these cases for clinical practice against resistant pneumococcal infection. The first case was a typical acute mastoiditis, although we have experienced only masked mastoiditis recently. The second case was meningitis with septicemia, which did not show any abnormality in the first obtained cerebrospinal fluid. The third case was recurrent bronchitis in a child with cerebral palsy. The minimum inhibition concentrations of these isolated strains were 0.25 microgram/ml in the second case an 2.0 microgram/ml in the first and third cases.

Adolescent↗

PubMed1994

Potassium/energy and phosphorus/calcium ratios reflect the quality of nutrition.

A nutritional survey and questionnaire regarding dietary habits were administered to 649 men ranging in age from 35 to 64 years receiving a one-day health screening examination. First, comparisons of nutrient intake based on the nutrient rate of the Recommended Dietary Allowances for Japanese (RDA), and the total score on the questionnaire regarding dietary habits according to the RDA rates of total energy and calcium (Ca) were investigated. Then, the comparisons of intake of food groups, intake of nutrients and the total score on the questionnaire regarding dietary habits according to potassium/energy (K/E) ratio and phosphorus/calcium (P/Ca) ratio were determined. Last, differences between comparisons with the nutrient rates of RDA and comparisons with K/E ratio and P/Ca ratio were investigated. The following results were obtained: 1. Even in the group with RDA rates of total energy or Ca of > or = 90% and < or = 110% the RDA rates of some other nutrients were out-side the appropriate range. 2. In the group with high K/E ratios, as compared to the group with low ratios, the intake of potatoes, pulses, fruits, green/yellow vegetables, other vegetables, soy sauce, other beverages, fish/shellfish, and milk products showed high values, while cereals and fats/oils showed low values. For this reason, in the former group as compared to the latter, the intake and RDA total energy rate showed low values whereas the intake and RDA rates of nutrients such as Ca, Fe, and vitamin A were low. 3. In the group with high P/Ca ratios, as compared to the group with low ratios, the intake of beer and meats showed high values while that of pulses, green/yellow vegetables, and milk products showed low values. For this reason, in the former group as compared to the other groups, despite the fact that the intake and RDA total energy rate tended to be higher, the intake of nutrients such as Ca, P, K, and vitamin A showed lower values. 4. The RDA rates of all of the nutrients of group with a high K/E ratio and the group with a low P/Ca ratio generally showed largely appropriate values. 5. These results suggest that indices reflecting the balance of minerals such as the K/E and P/Ca ratios more objectively reflect the quality of nutrition than comparisons based on the RDA rates of total energy and specific-nutrient.

Adult↗

PubMed1994

Comparative study on mortality patterns in Japan and China.

On the basis of the 1990 Chinese death notice data and 1990 Japanese populations vital statistical materials, the mortality patterns and proportions of individual causes of death in the two countries were compared. In both sexes, the mortality rates were the highest in almost all age groups in Chinese rural areas followed by urban areas and Japan. In Japan and in Chinese urban areas, malignant neoplasms cardiovascular diseases and cerebrovascular diseases were the major causes of death, with these three making up about 60% of the total. In Chinese rural areas, these three conditions were responsible for 43% of all deaths, a considerably lower figure as compared to those in the other two areas, and the mortality rates for infectious diseases and accident/suicide were higher than those in the other two areas. Of the three major adult diseases, cerebrovascular diseases were found to be especially frequent in both Chinese urban and rural areas. On the other hand, ischemic heart disease was found at comparable levels in Japan and China and the rate was lower than in other developed countries. Site-specific mortality rates for malignant neoplasms were characterized by high rates for lung, liver and esophageal cancers in China. The mortality rates for bronchitis in both Chinese urban and rural areas were markedly higher than those in Japan These differences in mortality rates and proportions of individual causes of death between China and Japan are thought to be attributable to the differences in medical services and the level of risk factors for each disease.

Adolescent↗

PubMed1994

[Toxicity studies of paclitaxel. (I)--Single dose intravenous toxicity in rats].

Paclitaxel, an antineoplastic agent, was given to Crj: CD (SD) rats of both sexes at 38, 50, 65 and 85 mg/kg by single intravenous administration to investigate its acute toxicity. The results obtained are summarized as follows: 1. Tachypnea and decreased activity with prone position were noted for vehicle and all paclitaxel groups, and alopecia for all paclitaxel groups. 2. Deaths occurred for one out of 5 males and 2 out of 5 females at 85 mg/kg. One female died of respiratory insufficiency induced by vehicle on Day 0. One female and one male died of the systemic toxicity of paclitaxel such as hypoplasia of the bone marrow and lymphoid depletion of lymphatic organs on Days 6 and 12, respectively. 3. On Days 4 and 5, all paclitaxel groups showed decreases of reticulocyte and white blood cell counts, as well as decrease of differential count of neutrophils. These changes were generally recovered by a week after dosing. 4. Histopathological examinations revealed atrophy of the thymic medulla, hypoplasia of the bone marrow and lymphoid depletion of the spleen for a few males at 85 mg/kg, and hypospermatogenesis and tubular atrophy of the testes for all paclitaxel groups. Based on these results, 85 mg/kg of paclitaxel was lethal to rats, and hematopoietic, lymphoid and male reproductive systems were primarily affected under this condition.

Alopecia↗

PubMed1994

[Toxicity studies of paclitaxel. (II)--One-month intermittent intravenous toxicity in rats].

Paclitaxel, an antineoplastic agent, was intravenously given to Crj:CD (SD) rats of both sexes at 0 (saline), 0 (vehicle), 1.0 (low dose), 3.3 (intermediate dose) and 10.0 (high dose) mg/kg at five-day interval over one-month period (6 times in total) to investigate its repeated dose toxicity and the reversibility of toxic effects. The results obtained are summarized as follows: 1. Decreased activity with prone position was observed for high dose and vehicle groups, and alopecia was seen for many high dose rats. Body weight gain and food intake were suppressed for high and intermediate dose groups. No deaths occurred. 2. Red blood cell count, hemoglobin, hematocrit, white blood cell count, relative neutrophil count, platelet count and reticulocyte count were decreased for high dose groups. Red blood cells count was also decreased for intermediate dose groups. 3. Thymic atrophy, splenic hematopoiesis, bone marrow hypoplasia, testicular atrophy with suppression of spermatogenesis and tubular atrophy, and epididymal atrophy were observed for high dose rats. 4. Above-described changes excluding the findings on the testis and epididymis for high dose rats were shown to be generally reversible. Based on these results, the no-toxic effect dose of paclitaxel was estimated to be 1.0 mg/kg in rats under this study condition.

Alopecia↗

PubMed1994

[Antigenicity study of paclitaxel].

The antigenic property of paclitaxel was examined using its protein mixtures (paclitaxel + OVA, paclitaxel + GSA, paclitaxel + RSA) in guinea pigs and mice in comparison with ovalbumin (OVA) and the protein conjugate of 4-aminoantipriyne (AAP). The following results were obtained: 1. When guinea pigs were sensitized with paclitaxel or paclitaxel + OVA emulsified with Freund's complete adjuvant, none of active systemic anaphylaxis (ASA), passive cutaneous anaphylaxis (PCA) and Schultz-Dale reaction were induced by challenge with paclitaxel or paclitaxel + GSA (guinea pig serum albumin). In the observation of active cutaneous anaphylaxis (ACA), no changes were observed in animals treated with paclitaxel alone as a sensitizing and/or a challenging antigen under the condition where slight delayed type hypersensitivity was elicited in animals sensitized with paclitaxel + OVA and challenged with paclitaxel + GSA. 2. When mice were sensitized with paclitaxel or paclitaxel + OVA adsorbed to alum. sera of these animals revealed a negative reaction in PCA using rats by challenge with paclitaxel or paclitaxel + RSA (rat serum albumin). 3. Protein bindings of paclitaxel with the above albumins were more than 40%. As shown above, paclitaxel was considered not to possess antigenic property under the experimental condition. In addition, the dose levels of paclitaxel employed in the present experiment were confirmed not to suppress the immune response to OVA.

Anaphylaxis↗

PubMed1994

[Irritability study of paclitaxel in rabbit ear vein].

The vascular irritability of paclitaxel at concentrations of 0.6 and 1.2 mg/ml was examined using the rabbit ear vein by a single intravenous drip in comparison with its vehicle consisting of ethanol and Cremophor, and physiological saline. The results were as follows: 1. Slight to moderate congestion was macroscopically observed around some injection sites of the retroauricular veins infused by paclitaxel, the vehicle and saline. Its incidence and severity caused by paclitaxel was not so much different from that caused by the vehicle or saline. 2. Histopathological findings at the injection sites of the rabbits treated with paclitaxel consisted of vascular and perivascular changes, as well as alterations of the dermis and epidermis. These changes were severer than those brought by saline, and dose-dependent in their incidence and severity. Moreover, the lesions caused by paclitaxel at a concentration of 1.2 mg/ml were correspondent to those caused by the vehicle. Based on these results, the microscopic examinations suggested that the vascular irritability of paclitaxel might be attributable to administration of the vehicle.

Animals↗

PubMed1994

[Toxicity studies of paclitaxel. (III)--Six-month intermittent intravenous toxicity in rats].

Paclitaxel, an antineoplastic agent, was intravenously given to Crj:CD (SD) rats of both sexes at 0 (saline), 0 (vehicle), 0.3 (low dose), 1.0 (intermediate dose) and 3.3 (high dose) mg/kg at seven-day interval over a six-month period (total of 27 doses) to investigate its repeated dose toxicity. The results obtained are summarized as follows: 1. No deaths occurred in this study. Vehicle-related salivation was seen for some high dose and vehicle control rats. Soiling of the perigenital region was observed for some high dose females. 2. Red blood cell count, hemoglobin, hematocrit and white blood cell count were decreased for high dose rats. Reticulocyte count was increased and relative neutrophil count was decreased for high dose males. 3. Relative erythroid and myeloid cell count were decreased for high dose rats in bone marrow smear examinations. 4. Bone marrow hypoplasia and splenic hemosiderosis were observed for high dose rats, and thymic atrophy and lymphoid depletion were seen for some high dose males. Based on the these results, the no-toxic effect dose of paclitaxel was estimated to be 1.0 mg/kg in rats under this study condition.

Animals↗