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Biomedical subjects

H Okuda

Publications and source records attributed to H Okuda.

At least 325 records · Page 18Linked to original sources
PubMed1986

Lateral geniculate kindling and long-lasting photosensitivity in cats.

The kindling response of the lateral geniculate body (GL) was compared with that of the amygdala, using cats. Daily electrical stimulation in the GL group led to the generalized tonic-clonic convulsion in most subjects and the resulting state of seizure susceptibility was long-lasting, as in the amygdala group. The kindling response of the GL differed from that of the amygdala in some respects, i.e., rapid kindling, short latency for seizure generalization, a different pattern of behavioral seizure development, and seizure regression during the course of kindling. The effects of photic stimulation with pentylenetetrazol administration were also examined before and after kindling in both groups. This study revealed that the photically induced myoclonus, at times proceeding to the generalized tonic-clonic convulsion, was provoked repeatedly as a result of GL kindling, whereas none of the amygdala-kindled cats showed such marked photosensitivity. These photically induced seizures were invariably observed for at least 4 weeks after GL kindling. Our results suggest that a neural mechanism participating in GL kindling is different from that in amygdala kindling, and that there might be cross-sensitization between seizure susceptibility resulting from GL kindling and photosensitivity.

Amygdala↗
PubMed1986

Effects of allylglycine on photosensitivity in the lateral geniculate-kindled cat.

The effects of DL-allylglycine, an inhibitor of GABA synthesis, on the responses to photic stimulation were studied in the cat kindled in the lateral geniculate body (GL). For 3 to 8 h after the injection of DL-allylglycine at a subconvulsant dose (30 or 40 mg/kg, i.v.), the kindled cat showed a stable level of photosensitivity without any toxic effects and responded with various degrees of myoclonus or a generalized tonic-clonic convulsion when photic stimulation was repeated at hourly intervals. The incidence of photically induced myoclonus reached its plateau during this period. Our results suggest that photosensitivity of the lateral geniculate-kindled cat is related to the modification of GABAergic mechanisms, and that when the GL-kindled cat is pretreated with DL-allylglycine it is a reliable model of photosensitive epilepsy.

Allylglycine↗
PubMed1986

Studies on a protein kinase inhibitor-insensitive, phospholipase C-sensitive pathway of lipolysis in rat adipocytes.

Endogenous lipid droplets were prepared by subjecting fat cells to hypotonic shock and Triton X-100 treatment. The endogenous lipid droplets were found to show lipolysis in response to epinephrine, but not to show lipogenesis from glucose in response to insulin. These results indicated that the preparation of endogenous lipid droplets did not contain any intact fat cells capable of insulin-stimulated lipogenesis. Results with these endogenous lipid droplets showed that protein kinase inhibitor inhibited protein kinase-mediated hormone-sensitive lipase activity but did not reduce epinephrine-induced lipolysis. Cyclic AMP and dibutyryl cyclic AMP induced lipolytic activity in the presence of 80 mM KCl and their activities were not inhibited by protein kinase inhibitor. Phospholipase C inhibited epinephrine, cyclic AMP and dibutyryl cyclic AMP-induced lipolysis, but did not affect the lipolytic activity of either the activated or non-activated form of hormone-sensitive lipase. These results indicate the existence of a protein kinase inhibitor-insensitive and phospholipase C-sensitive lipolytic pathway in rat adipocytes.

Adipose Tissue↗
PubMed1986

Studies of the hepatocellular uptake of the hepatobiliary scintiscanning agent 99mTc-DISIDA.

Bilirubin (BR) and organic anionic dyes such as sulfobromophthalein (BSP), indocyanine green (ICG) and rose bengal (RB) enter the hepatocyte by a specific non-sodium-dependent membrane transport system. Two analogous but distinct Na+-dependent transport systems effect the uptake of conjugated bile acids such as taurocholate (TC) and free fatty acids such as oleate, respectively. The mechanism of uptake of the acetanilidoiminodiacetic acid (HIDA) class of biliary scintiscanning agents is unknown. Accordingly, rat hepatocytes were isolated by collagenase perfusion of the liver and differential centrifugation, and incubated with 99mTc-diisopropyl-HIDA (99mTc-DISIDA) alone, or in the presence of various concentrations of BSP, ICG, RB, oleate or TC, with and without bovine serum albumin (BSA). Initial uptake velocity (Vo) was determined from the initial slope of the cumulative radioactivity/time curve. In albumin free media, uptake of 99mTc-DISIDA was temperature- and pH-dependent, with maximal uptake at 37 degrees C. There was virtually no uptake of inorganic 99mTc. In incubations containing 15-1500 microM 99mTc-DISIDA, Vo was saturable, with estimated Vmax = 65 nmoles/min/10(6) hepatocytes, and Km = 1200 microM. In keeping with its weak albumin binding, 99mTc-DISIDA Vo was only minimally influenced by equimolar concentrations of BSA. 99mTc-DISIDA Vo was inhibited by BR, BSP, ICG and RB, as well as by a rabbit antibody to the rat liver plasma membrane BSP/BR binding protein. Surprisingly, Vo was also inhibited by TC and oleate, but not influenced either by ouabain or by substitution of Li+ for Na+ in the medium.(ABSTRACT TRUNCATED AT 250 WORDS)

Albumins↗
PubMed1986

Ca2+,Mg2+-ATPase of microsomal membranes from bovine aortic smooth muscle: effects of Sr2+ and Cd2+ on Ca2+ uptake and formation of the phosphorylated intermediate of the Ca2+,Mg2+-ATPase.

The effects of various divalent cations on the Ca2+ uptake by microsomes from bovine aortic smooth muscle were studied. High concentrations (1 mM) of Co2+, Zn2+, Mn2+, Fe2+, and Ni2+ inhibited neither the Ca2+ uptake by the microsomes nor the formation of the phosphorylated intermediate (E approximately P) of the Ca2+,Mg2+-ATPase of the microsomes. The cadmium ion, however, inhibited both the Ca2+ uptake and the E approximately P formation by the microsomes. Dixon plot analysis indicated Cd2+ inhibited (Ki = 135 microM) the Ca2+ dependent E approximately P formation in a non-competitive manner. The inhibitory effect of Cd2+ was lessened by cysteine or dithiothreitol. The strontium ion inhibited the Ca2+ uptake competitively, while the E approximately P formation increased on the addition of Sr2+ at low Ca2+ concentrations. At a low Ca2+ concentration (1 microM), Sr2+ was taken up by the aortic microsomes in the presence of 1 mM ATP. It is thus suggested that Sr2+ replaces Ca2+ at the Ca2+ binding site on the ATPase.

Animals↗
PubMed1986

Reno-colic-cutaneous fistula.

A case of reno-colic-cutaneous fistula is presented. Of several diagnostic methods, fistulography combined with computerized tomography was the most useful to locate the precise anatomical site of involvement. Total nephrectomy, resection of the descending colon and excision of the retroperitoneal abscess were successfully performed.

Colonic Diseases↗
PubMed1986

Hemodynamic response to exercise in patients 2 to 6 years after Rastelli operation.

We studied hemodynamic response to exercise in eight patients who had undergone Rastelli operation 2 to 6 years before this study. Endurance time for the treadmill test was below the low limit of two standard deviations of our normal value in 5 out of 7 patients. On bicycle ergometer exercise test during catheterization, cardiac output increased from 3.8 +/- 0.96 liter/min/m2 to 6.5 +/- 1.7 liter/min/m2 when heart rate increased 81 +/- 10 to 123 +/- 17, the latter reaching 71% of the maximum value. Right ventricular pressure increased from 85 +/- 38 mmHg to 114 +/- 45 mmHg, along with elevation of the enddiastolic pressure (+5 +/- 4 mmHg). Right-sided ventricular ejection fraction increased in 3 out of 6 patients, while left-sided ventricular ejection fraction increased in 4 out of 7 patients. Thus, ventricular pump function does not respond normally to physical activity in many patients after Rastelli operation.

Adolescent↗
PubMed1986

Clinico-pathological changes induced in rats treated with amine-curing agent for epoxy resin, bis(4-amino-3-methylcyclohexyl)methane.

Amine-curing agent for epoxy resin, bis(4-amino-3-methyl-cyclohexyl)methane (commercial name; Laromin C) has been suspected to have induced in the workers some toxic signs such as collagen disease like scleroderma or polymyositis. Subacute toxicity of this agent was studied in rats following repeated oral administration. The agent was given orally at 5 dose levels (25 mg/kg to 100 mg/kg per one dose) for periods ranging from 10 days to 4 weeks. After the completion of administration, clinico-biochemical tests and histopathological examinations were carried out. In a few cases, skeletal muscles and choroid plexus of the brain were examined by electronmicroscopy. Clinico-biochemical tests revealed some elevation of muscle-derived components such as GOT and CPK as seen in the myopathic diseases. Histologically, various degrees of atrophy, degeneration and regeneration of muscle fibers and a numerical increase of interstitial cells were observed in the skeletal muscles. Electronmicroscopical examination of the gastrocnemius muscle revealed intrasarcoplasmic osmiophilic round-shaped inclusion bodies, sometimes with lamellar structure, which were suggestive of some lipidosis. The epithelial cells of choroid plexus in the brain ventricles represented various degrees of vacuolar changes lightmicroscopically, which were suggested to be dilated smooth endoplasmic reticulum electronmicroscopically. Although scleroderma-like changes were not observed in our experiments, the results suggest that this amine-curing agent for epoxy resin could be one of the causative agents which induced toxic lesions like some collagen diseases including muscle lesions in the workers. In addition, it is considered that the agent may have systemic toxic effects.

Animals↗
PubMed1986

[A case of multiple liver metastases from sigmoid carcinoma treated successfully with arterial infusion chemotherapy].

A 63-year-old female, who had undergone sigmoidectomy for sigmoid carcinoma one year before, was admitted for multiple liver metastases. A urokinase-immobilized catheter was introduced into the proper hepatic artery via the gastroepiploic artery operatively. A daily arterial infusion of 5-FU (250 mg) was combined with a weekly arterial infusion of adriamycin (30 mg) or MMC (10 mg). After discharge, 5-FU (200 mg/day) was given orally and MMC (10 mg) was infused intraarterially every other week at an outpatient clinic. ADR or MMC was infused with angiotensin II, known to increase arterial blood supply to a malignant lesion. Ultrasonography demonstrated 35 to 50% reduction in tumor diameter. The density of metastases seen in computerized tomography became low indicating tumor necrosis. Plasma CEA level, which had initially been as high as 864 ng/ml, decreased rapidly and has remained within normal limits up to the present time. Arterial infusion chemotherapy using 5-FU, ADR or MMC in combination with angiotensin II seems to be effective in the treatment of multiple hepatic metastases from colorectal carcinoma.

Adenocarcinoma↗
PubMed1986

Effect of soya saponins on gold thioglucose (GTG)-induced obesity in mice.

The effect of oral administration of total soya saponins (TS) on the development of obesity induced by (GTG) injection was examined. In the GTG-obese group, the serum immunoreactive insulin (IRI) levels were significantly increased and food consumption was suggestively increased. In addition, sucrase activity in the intestinal mucosa was increased and the surface area of intestinal villi was significantly greater, suggesting enhanced gastrointestinal function. Oral administration of TS prevented development of obesity and prevented an increased level of IRI in GTG-obese animals. It also restored the sucrase activity and the surface area of intestinal villi to normal. Thus, TS may be effective in preventing development of obesity.

Animals↗