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Biomedical subjects

G Kobayashi

Publications and source records attributed to G Kobayashi.

At least 73 records · Page 4Linked to original sources
PubMed1990

[A case of a chronic traumatic thoracic aneurysm with compression of left main bronchus at the isthmus].

A case of successfully treated chronic traumatic thoracic aneurysm is reported. A 43-year-old man was admitted suffering from severe respiratory distress. He had a history of a blunt chest trauma in a traffic accident twenty-three years ago. A plain chest film, bronchofiberscopy, chest CT, MRI and angiography revealed a calcified aneurysm with compression of left main bronchus at the isthmus. He was successfully treated by replacement with woven Dacron graft under partial left heart bypass by means of a centrifugal pump. His postoperative course was uneventful. The literature states operative cases demonstrate a significantly higher survival rate compared to the nonoperative cases. Surgical treatment should be strongly considered for potential aortic rupture.

Adult↗
PubMed1990

[Augmentation of cytotoxicity of regional lymph node lymphocytes of gastric cancer after intratumoral injection of OK-432].

Although regional lymph node lymphocytes (LNL) are thought to be a barrier of the immunological surveillance, their natural cytotoxicity is strongly suppressed. In this study, an immunopotentiator OK-432 (10K.E.) was injected into gastric cancer lesions under endoscopy 1 week before operation, and the effects on the cytotoxicity of LNL were examined by single cell assay. This assay is characterized by assessment of killer cell frequency in preventing the killer cells from recycling by their fixation in agarose, and by direct microscopic observation of both binding and killing phases. NK sensitive cell line K562 was used as target cells. By intratumoral injection of OK-432, the killer cell frequency of LNL in 8 out of 20 cases was elevated to almost equal level as that of peripheral blood lymphocytes. In clinical stages these 8 cases belonged to early stages (stage I 7 cases, stage II 1 case). In LNL subsets of OK-432 injected cases, the percentage of OKT8 positive cells was decreased and the ratio of OKT4 and OKT8 was significantly increased compared with non-injected group.

Adult↗
PubMed1989

Carcinoid tumor of the bile duct: case report.

Carcinoid tumor of the bile duct is extremely rare. Ten cases have been reported in the literature. This report describes the eleventh case. A 55-year-old woman was hospitalized with biliary stenosis. Sonography (US) and computed tomography (CT) demonstrated a tumor in the upper common hepatic duct (CHD). Percutaneous transhepatic cholangiography showed extraluminal growth of the tumor. The tumor was resected and histologic examination showed carcinoid tumor of the common hepatic duct.

Bile Duct Neoplasms↗
PubMed1989

Early embryonic development in Thai swamp buffalo (Bubalus bubalis ).

A total of 33 nonsurgical embryo collections was carried out to investigate early embryo development in Thai swamp buffalo. Collections were performed on Days 5.5, 6.0, 6.5, 7.0 and 7.5. The different stages of embryo development on these days were the 16-cell stage, compact morula, blastocyst, hatched blastocyst and hatched expanding blastocyst, respectively. In addition, some degenerating embryos and unfertilized ova were also recovered. A higher recovery rate was obtained with single embryo collection after natural estrus than after induced estrus or superovulation, 78% (7 9 ) vs 46% (6 13 ) vs 54.5% (6 11 ), respectively. A higher percentage of normal embryos was also obtained with single embryo collection after either natural or induced estrus than after superovulation, 71% (5 7 ), 83% (5 6 ) and 38% (6 16 ), respectively.

Journal Article↗
PubMed1989

Vascular dilatory action of Artemisia capillaris bud extracts and their active constituent.

In perfusion experiments, the acetone extract of Artemisia capillaris buds significantly inhibited the response to norepinephrine of helical strips of rabbit thoracic aorta. The acetone extract was fractionated by column chromatography to identify the active constituent. Kinetic experiments using rabbit thoracic aorta showed that 6,7-dimethoxycoumarin (scoparone) has a marked inhibitory effect on the contractions induced by norepinephrine, 5-hydroxytryptamine, histamine and angiotensin II. Like nitroglycerin, scoparone appeared to be a competitive antagonist of norepinephrine.

Animals↗
PubMed1989

The effect of scoparone, a coumarin derivative isolated from the Chinese crude drug Artemisiae capillaris flos, on the heart.

In the present study, scoparone isolated from Artemisia Capillaris Flos has been investigated to determine its pharmacological properties on the heart. Scoparone was found to cause the increase in coronary flow and heart rate, but did not affect cardiac output, left ventricular pressure or left ventricular work in the isolated perfused heart. Scoparone at 25 mg/kg and 50 mg/kg, p.o. had a marked inhibitory effect on the ST wave depression. Consequently it is suggested that scoparone has antianginal action.

Animals↗
PubMed1989

Vascular dilatory action of the Chinese crude drug. II. Effects of scoparone on calcium mobilization.

Further experiments were conducted to examine the effect of scoparone (6,7-dimethoxycoumarin), a coumarin derivative found in the Chinese crude drug "Capillaris Flos," on calcium mobilization. Scoparone does not affect Ca2+ influx through the voltage-dependent channel due to membrane depolarization. Its inhibitory action may be dependent not only on the inhibition of Ca2+ release from sarcoplasmic reticulum but also on the inhibition of extracellular Ca2+ influx through the receptor-operated channel.

Animals↗
PubMed1989

[Superselective angiography of the cystic artery for diagnosis of gallbladder diseases].

Superselective angiography of the cystic artery was attempted with 18 patients for the purpose of improving angiographic diagnosis of gallbladder diseases. The success rate of cystic angiography using a fine catheter (5 Fr. size) and a specially coated guidewire was 72% (13/18). In comparison with usual hepatic angiography findings obtained by cystic angiography proved easier to evaluate, because the angiograms thus obtained avoided visualization of the hepatic artery and showed good opacification of the fine branches of the cystic artery. It is concluded that angiographic diagnosis of gallbladder diseases can be improved by use of superselective cystic angiography.

Angiography↗
PubMed1988

The vasorelaxant effect of evocarpine in isolated aortic strips: mode of action.

The effect of evocarpine (EVO), a quinolone alkaloid isolated from Evodiae fructus, on Ca2+-blocking activity has been examined. In the isolated rat thoracic aorta evocarpine significantly inhibited the contraction induced by 60 mM K+ with an IC50 of 9.8 microM, and that induced by external Ca2+ in the depolarized muscle in concentrations of 10-100 microM. The relaxant effect of evocarpine and verapamil was antagonized by Bay K8644. The increase of 45Ca2+-influx induced by 60 mM K+ was significantly inhibited by 100 microM evocarpine. In the isolated rabbit thoracic aorta 100 microM evocarpine had no effect on the norepinephrine-induced contraction in normal medium or on the phasic contraction in Ca2+-free medium or on the transient relaxation induced by activation of the Na+ pump. The content of cyclic AMP or cyclic GMP was unchanged. These results suggest that evocarpine inhibits Ca2+ influx through voltage-dependent calcium channels.

Alkaloids↗
PubMed1988

Effect of alismol on adrenergic mechanism in isolated rabbit ear artery.

Effects of alismol, a sesquiterpenoid isolated from the rhyzome of Alisma orientale, on adrenergic mechanisms were examined in the isolated rabbit ear artery. Alismol (10(-6) to 10(-4) M) inhibited the contraction of isolated rabbit ear artery by electrical stimulation of the perivascular nerves. The inhibition was concentration-dependent; at a concentration of 10(-4) M, the inhibition was 90% (n = 8). Treatment with 10(-4) M alismol inhibited the increase in 3H-noradrenaline (3H-NAd) release induced by electrical stimulation by 63 +/- 6%. Alismol at 10(-4) M did not affect the neuronal uptake of 3H-NAd in the artery. Alismol at 10(-4) M slightly inhibited contractions induced by exogenously administered NAd. These results demonstrate that alismol inhibits the adrenergic neuro-effector mechanisms in rabbit ear artery, and they suggest that alismol acts primarily on nerve terminals and inhibits their responses to electrical stimulation by interfering with NAd release.

Animals↗
PubMed1987

Effects of alismol isolated from Alismatis Rhizoma on calcium-induced contraction in the rabbit thoracic aorta.

We examined the inhibitory effects of alismol, a sesquiterpenoid isolated from Alismatis Rhizoma, on vascular contractions induced by high concentrations of K+ and Ca2+, and on 45Ca2+ retention in normal and in high K+-containing medium. Alismol affected neither the resting tension nor the 45Ca2+ retention in normal medium, but it inhibited sustained contraction and increased 45Ca2+ retention induced by high K+ concentrations. Alismol did not affect norepinephrine-induced contractions in normal medium, nor phasic contractions in Ca2+-free medium. These results suggested that alismol inhibited mainly Ca2+ influx through a voltage-dependent Ca2+ channel.

Animals↗
PubMed1987

[Screening test for calcium antagonist in natural products. The active principles of Uncariae ramulus et uncus].

We have previously reported on the Ca2+-blocking activity and active constituents of natural products. In the course of screening, Uncariae ramulus et uncus, a chinese herbal medicine, was found to possess such activity. In this paper, we attempted to characterize its active constituent which plays an important role in Ca2+-blocking activity. Its active principles were identified to be oxyindole-type alkaloids, rhynchophylline, corynoxeine, isorhynchophylline and isocorynoxeine, that showed inhibitory effects, similar to that of verapamil, on contractile response to high concentration of potassium ion (rats), CaCl2 (rats), norepinephrine in normal and Ca2+-free medium (rats and rabbits) and 45Ca2+-uptake (rats) in thoracic aorta with an activity two orders of magnitude less than the activity of verapamil.

Alkaloids↗
PubMed1986

Correlation between pathogenicity and temperature sensitivity in different strains of Histoplasma capsulatum.

We compared the mycelial to yeast transitions of the Downs strain of Histoplasma capsulatum (low level of virulence) with those of G184A and G222B, two more virulent strains having different levels of pathogenicity for mice. When the morphological transitions are initiated by a temperature shift from 25 degrees to 37 degrees C, all three strains undergo similar physiological changes, but these are less severe in G184A and G222B than in the Downs strain. The transitions from mycelial to yeast morphology in both of the more virulent strains are also one-third more rapid than in Downs. We also find that the differences in temperature sensitivity of the three strains can be correlated with the temperature required for complete uncoupling of oxidative phosphorylation. The differences in sensitivity to elevated temperatures extend to the growth of yeast cells of all three strains. Considered together, our results suggest that sensitivity to elevated temperatures may be a key factor accounting for differences in virulence and that uncoupling of oxidative phosphorylation may be the primary event in the morphological transition in all three strains.

Adenosine Triphosphate↗
PubMed1983

Immune enhancement in mice by ara-A.

Ara-A in single, apparently nontoxic doses stimulates murine immune responses to several well-defined antigens. Both humoral and cell-mediated responses are enhanced by ara-A, but not all mouse strains respond equally well. In certain mouse strains, ara-A also promotes increased (or decreased) survival during experimental infection with Cryptococcus neoformans, suggesting that clinically significant effects on host resistance may result from the use of ara-A as an antiviral therapeutic agent. The biochemical mechanisms of action of the aranucleosides suggest that the immunostimulation produced by ara-A depends on suppressor cell toxicity.

Adjuvants, Immunologic↗
PubMed1982

Rubella seroepidemiology in Hawaii.

To determine rubella susceptibility levels 10 years after the introduction of the rubella vaccine in Hawaii, a large-scale serosurvey was conducted in conjunction with a campaign to raise the immunity levels of adolescent and adult women. Each woman tested for rubella antibody was asked her age, ethnic group, migration history, number of siblings, vaccination history, and the occupation of the head of the household. In the period from September 1977 through June 1979, serum specimens acceptable for analysis were collected from 3,852 women; 23.8% were susceptible (haemagglutination inhibition antibody titre less than 8) to rubella. A statistical analysis by fitting log-linear models revealed that rubella vaccination history, birthplace, ethnic group, number of siblings and island of residence appear to be factors related to rubella susceptibility. Although caution must be used in comparing this survey with previous surveys, the relatively low rubella susceptibility rate found in this survey may represent a true decrease in rubella susceptibility due to the rubella vaccination programme.

Adolescent↗