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Biomedical subjects

T Kudo

Publications and source records attributed to T Kudo.

At least 433 records · Page 24Linked to original sources
PubMed1992

Concentration and uptake of taurine in umbilical blood platelets.

The concentration and uptake of taurine in the umbilical and adult blood platelets were studied. Taurine was the most abundant free amino acid in both umbilical and adult blood platelets. The taurine concentration in umbilical blood platelets (2.30 pmoles/10(4) cells) was significantly lower than that of adult blood platelets (3.27 pmoles/10(4) cells) in contrast to the reverse relationship in taurine concentrations in umbilical and adult blood plasma. No other amino acid showed such significant difference in the concentrations between umbilical and adult blood platelets. Taurine uptake into umbilical blood platelets was temperature sensitive and sodium-dependent in a manner similar to that of adult blood platelets. The uptake conformed well to Hanes-plot. The Vmax of the uptake into adult blood platelets was about 3.6 times higher than that of umbilical blood platelets, but no significant difference was seen in the Km value between the two groups.

Amino Acids↗
PubMed1992

Platelet taurine concentration and uptake in gestosis patients with edema, proteinuria and hypertension.

The taurine concentration and uptake in platelets obtained from normal pregnant women and gestosis patients with edema, proteinuria and hypertension (EPH gestosis) were investigated. The taurine concentration in platelets showed a marked increase in severe EPH gestosis compared with normal pregnancy or mild and moderate EPH gestosis, while the plasma taurine concentration did not change significantly. Taurine uptake in platelets paralleled the severity of EPH gestosis. The Vmax of the uptake in severe EPH gestosis was about 2.4 times higher than that in normal pregnancy or mild and moderate EPH gestosis, but no significant difference was seen in the Km value among these groups.

Adult↗
PubMed1992

A new inhibitor of protein kinase C, RK-1409 (7-oxostaurosporine). I. Taxonomy and biological activity.

A novel inhibitor of protein kinase C was found in the fermentation of a soil actinomycete, strain RK-1409. According to the taxonomic studies, the producing strain was designated as Streptomyces platensis subsp. malvinus RK-1409. The protein kinase C inhibitor, RK-1409 (7-oxostaurosporine) inhibited the morphological change of a human chronic erythroleukemia cell, K-562, induced by phorbol 12,13-dibutyrate (PDBu) at the concentration of 10 ng/ml. The concentration of 3 ng/ml inhibited the activity of protein kinase C in vitro. RK-1409 inhibited the cell cycle progression at G2 phase of K-562 cells.

Alkaloids↗
PubMed1992

Totally synthetic analogues of siastatin B. II. Optically active piperidine derivatives having trifluoroacetamide and hydroxyacetamide groups at C-2.

Siastatin B analogues, optically active 2-(trifluoroacetamide)- 3,4,5-trihydroxypiperidines having nitromethyl, aminomethyl and carboxyl branched groups at C-5, and (+)-(2R,3R,4R,5R)-5-(aminomethyl)-3,4,5-trihydroxy-2- (hydroxyacetamido)piperidine have been obtained total synthetically from D-ribono-1,4-lactone. Some analogues have inhibitory activity against some glycosidases, and (+)-(2R,3R,4R,5R)-2-(trifluoroacetamido)-3,4,5-trihydroxypiperi dine-5-carboxylic acid showed a marked inhibitory activity against beta-glucuronidase.

Anti-Bacterial Agents↗
PubMed1992

Prophylactic oral acyclovir in outbreaks of primary herpes simplex virus type 1 infection in a closed community.

Oral acyclovir was given prophylactically to 37 children in the early stages of three outbreaks of herpes simplex virus type 1 (HSV-1) infection and the results were compared with those in untreated control subjects in two other outbreaks. The rates of seroconversion to HSV were significantly reduced in children treated with acyclovir compared with control subjects (91% vs 27%, P less than .001). The incidence of symptomatic disease was also significantly reduced (82% vs 0%, P less than .001). In some children receiving prophylactic acyclovir, anti-HSV antibody titers did not rise despite the presence of replicative HSV on throat swabs just before the start of treatment. Restriction endonuclease analysis of isolated HSV-DNA confirmed that one strain was responsible for the five outbreaks. No resistance to acyclovir was detected during the study, and no adverse effects of treatment were noted. In conclusion, short-term prophylactic acyclovir may limit the spread and reduce clinical manifestations of HSV infections in closed communities, although this use should be restricted to communities where severe symptoms are observed.

Acyclovir↗
PubMed1992

Activation of cathepsin B involved in enkephalin production by bradykinin and its cleavage products in cultured fibroblasts of the rat dental pulp.

Mechanisms of cathepsin B activation involved in methionine-enkephalin (ME) production induced by bradykinin (BK), des-Arg9-BK or L-arginine (L-Arg) were studied using cultured fibroblasts of the rat dental pulp, especially from a viewpoint of intracellular signal transduction. BK, des-Arg9-BK, L-Arg or cysteine enhanced the release of ME-like peptides from the cells, and the release of ME-like peptides induced by des-Arg9-BK was inhibited by des-Arg9-[Leu8]-BK (BK B1-receptor antagonist) and E-64 (a specific inhibitor of cysteine proteinases). The activation of cathepsin B by BK or des-Arg9-BK was inhibited by des-Arg9-[Leu8]-BK or islet-activating protein (IAP), and the activation of cathepsin B by L-Arg was inhibited by Leu-Arg (kyotorphin-receptor antagonist) or Botulinum C3-enzyme. The activation of cathepsin B by those stimulants was dependent on calcium ion. These results suggest that the ME production by BK or des-Arg9-BK may be mediated by Ca(2+)-dependent cathepsin B activation through B1-receptors and IAP-sensitive G-proteins, whereas the production by L-Arg may be mediated by Ca(2+)-dependent cathepsin B activation through kyotorphin-receptor and Botulinum C3-enzyme-sensitive G-proteins. On the other hand, the activation of cathepsin B was inhibited by neomycin B (phospholipase C inhibitor) and various serine/threonine kinase inhibitors. These results indicate that phospholipase C and serine/threonine kinases are involved in the activation of cathepsin B by BK, des-Arg9-BK or L-Arg. Genistein inhibited the activation of cathepsin B by des-Arg9-BK or L-Arg in a different fashion, suggesting that tyrosine kinase(s) is also involved in the activation. Cathepsin B activation by BK or L-Arg but not des-Arg9-BK was inhibited by L-NMMA (inhibitor of NO synthesis), and the activation by L-Arg was enhanced by beta-glycerophosphate (beta-GP: inhibitor of phosphatases), while the activation by BK or des-Arg9-BK was inhibited by beta-GP. These results suggest that BK-induced cathepsin B activation in the fibroblasts may be due to a combined effect of des-Arg9-BK and L-Arg.

Animals↗
PubMed1992

[The phase IV studies with Estracyt in prostatic cancer--supplementary report: results of long-term therapy].

Two hundred patients with prostatic cancer were enrolled in our previous study between 1984 and 1987. In this study, 96 patients of them were observed for 1 year or more after oral administration of Estracyt (estramustine sodium phosphate). Of these 96 cases, 33 patients were treated with Estracyt as primary treatment and 63 patient had been treated with other treatments before Estracyt treatment. Twelve patients were treated only with Estracyt and 84 patients also received other treatments. Thirty-eight patients were on primary therapy, 37 patients were on maintenance therapy, and 11 patients were on primary therapy, 37 patients were on maintenance therapy, and 11 patients were on the re-activated stage therapy and 10 patients were others. In conclusion, among the 67 cases in which the due judgement of the effect was possible, Estracyt was markedly effective in 10 cases (14.9%), effective in 16 cases (23.9%), slightly effective in 15 cases (22.4%) and ineffective in 26 cases (38.8%). The survival rate was 92.6% at the first year, 66.0% at the third year and 46.3% at the fifth year in the follow-up study. Adverse reactions were observed in 22 cases (22.9%), among which the administration was discontinued in 3 cases.

Aged↗
PubMed1992

[A relationship between plasma ANP concentration and hemodynamics during PEEP--evaluation by transesophageal ECHO cardiography].

This study was undertaken to find which cardiac function indices as judged by transesophageal ECHO cardiography (TEE) would accurately predict the plasma ANP levels during PEEP. Fourteen patients who underwent orthopedic surgery were the subjects of the study. PEEP 10 cmH2O or 15 cmH2O was added with a PEEP valve during mechanical ventilation under general anesthesia. The cardiac function indices were measured using a 5 MHz TEE probe and plasma ANP levels were evaluated by radioimmunoassay. There were significant reductions in the left atrial diameter, cardiac output and pulmonary venous flow during PEEP, while A/R and CVP were significantly increased. The plasma ANP concentration decreased significantly from 39.2 +/- 4.8 pg.ml-1 at pre PEEP period to 26.8 +/- 3.1 pg.ml-1 at PEEP 15 cmH2O (mean +/- SE, P less than 0.05). However, we could not find any significant correlation between the cardiac function indices and ANP levels. The secretion of ANP from the heart is regulated mainly by stretch tension of the atrium. PEEP increases the pericardial pressure. Therefore, it seems to be difficult to predict the stretch tension of the atrium using TEE under PEEP.

Adult↗
PubMed1992

[Effects of sevoflurane anesthesia on dopamine metabolism in the rat brain].

To elucidate the mechanism of general anesthesia, effects of sevoflurane anesthesia on dopamine metabolism in rat brain were studied. Sevoflurane 3% was administered for 20 minutes to Wistar male rats weighing 230-270 g under spontaneous respiration. The rats were sacrificed by decapitation and the brains were rapidly removed. They were dissected into nine discrete regions, locus coeruleus, pons plus, medulla oblongata, hypothalamus, thalamus, basal ganglia, midbrain, hippocampus, amygdala and cerebral cortex. The contents of dopamine (DA) and its major metabolites, 3, 4-dihydroxyphenyl acetic acid (DOPAC) and homovanillic acid (HVA) were measured by high performance liquid chromatography with the dual-cell coulometric detector before anesthesia, 20 minutes after the start of anesthesia and at the recovery from anesthesia. Significant increases in DA levels were observed in the pons, hypothalamus, thalamus and amygdala by sevoflurane anesthesia as compared with the control group. DOPAC levels increased significantly in the pons, hypothalamus, basal ganglia and cerebral cortex at the recovery from anesthesia. A significant increase in HVA levels was observed in amygdala by sevoflurane anesthesia, while an appreciable decrease in HVA levels was observed in hippocampus at recovery from anesthesia. It is concluded that DA metabolism is significantly suppressed in the pons, hypothalamus, thalamus, basal ganglia, midbrain and amygdala during sevoflurane anesthesia and this change in DA metabolism may be associated with the mechanism of sevoflurane anesthesia.

Anesthetics↗
PubMed1992

[Pharmacokinetics of ketamine and pentazocine during total intravenous anesthesia with droperidol, pentazocine and ketamine].

Pharmacokinetics was studied in ten surgical patients who underwent various operative procedures of about 4 hours under total intravenous anesthesia with droperidol, pentazocine and ketamine (DPK). Plasma levels of ketamine, its metabolites and pentazocine were determined thirteen times during and after DPK. During anesthesia, ketamine (KO) and norketamine (KMI) levels ranged from 0.7 to 1.0 micrograms.ml-1 and from 0.09 to 0.74 micrograms.ml-1, respectively. A small amount of dehydronorketamine (KM II) was detected only 90 min after the start of DPK anesthesia. Plasma half-lives of ketamine were calculated to be 33 min for distribution phase (alpha phase) and 60 min for elimination phase (beta phase), respectively. Pentazocine levels decreased 300 min after the induction of DPK to 10% of the control level measured 5 min after its injection. Plasma half-lives of pentazocine were 60 min for alpha phase and 140 min for beta phase, respectively. The data obtained in this clinical study show that pharmacokinetics of ketamine during DPK is almost similar to that of DFK.

Adolescent↗
PubMed1992

Effects of warfarin at beginning doses on patients with valve replacement.

Warfarin administered to patients with valve replacement at a dose of 0.1 mg/kg for 2 days after surgery, and blood levels of warfarin, TT, PT, HPT, total vitamin K and vitamin K1-epoxide were determined at various time intervals after the administration of the drug. The measurements were obtained from 15 patients: 8 patients with AVR, 6 patients with MVR, and 1 patient with DVR. The blood levels of warfarin reached a peak of 462 +/- 160 ng/ml 6 hours after the administration, TT, PT and HPT were 40% of the initial values 24 hours after the administration, and vitamin K1-epoxide was 1.28 +/- 0.30 ng/ml 24 hours after the administration. It is clear from the results that warfarin exhibits sufficient anticoagulant effects at a beginning dose of 0.1 mg/kg after surgery to prevent a sudden decrease in blood coagulation.

Blood Coagulation Factors↗
PubMed1992

[Tryptophan and its metabolite concentrations in human plasma during the perinatal period].

The concentration of tryptophan (free and protein bound) and its metabolites in the plasma of the maternal vein and in the umbilical vein, umbilical artery and neonatal vein were determined by high performance liquid chromatography. The plasma levels of tryptophan and most of its metabolites in the umbilical vein and artery were significantly higher than those in the maternal vein. Especially the 3-OHAA level in umbilical blood was approximately 50 times as high as that in maternal blood. The concentration of total tryptophan in the plasma of the neonatal vein showed a marked decrease at one day after birth in comparison with that at birth, but the total kynurenine concentration was not decreased in the plasma of the neonatal vein. In the blood, ratios of free to total tryptophan and kynurenine were kept at a constant level throughout the perinatal period. In conclusion, the present study suggests that tryptophan metabolism may play an important role in fetal development.

Chromatography, High Pressure Liquid↗
PubMed1992

[Use of the newly designed long-handled forceps for respiratory surgery].

We report on use of the newly designed long-handled forceps for respiratory surgery. The forceps have a curved-end in the same plane as its handles. This contributes to the easier clamping of vessels running horizontally in the deep fields. It is very useful not only in thoracic surgery, such as respiratory and esophageal surgery, but also in pelvic surgery.

Equipment Design↗
PubMed1992

[A case report of true palmar aneurysm].

True palmar aneurysm is a rare disease of the hand. Only 12 cases of true palmar aneurysm have been reported in Japan. This occurs commonly in the hypothenar region. We experienced a 12-year-old boy who had a aneurysm of the left palmar hand successfully treated by surgery. The clinical diagnosis was established by ultra sound. Vascular reconstruction by end to end anastomosis was performed after excision of aneurysm. Pathology revealed this was true aneurysm.

Anastomosis, Surgical↗