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Biomedical subjects

H Kojima

Publications and source records attributed to H Kojima.

At least 685 records · Page 38Linked to original sources
PubMed1981

Propagation of human hepatitis A virus in conventional cell lines.

Fecal extracts of hepatitis A (HA) patients were selected for the presence of hepatitis A virus (HAV) by radioimmunoassay (RIA) and immune electron microscopy (IEM). When FL and Vero cells were inoculated with fecal extracts containing HAV, development of hepatitis A antigen (HAAg) was evident in the cytoplasm of the two cell lines by the indirect immunofluorescence (IF) test. The antigen was detectable in the cells 12 hr postinoculation (pi), and reached a plateau within two days pi. FL cell cultures inoculated with a specimen containing HAV were harvested and passaged four times. During the passages, efficient production of HAAg was confirmed in the infected cultures by three different serological tests: The indirect IF test, RIA using fixed cells, and RIA by the sandwich method. At the second and fourth passages, HAV particles were recovered in abundance from infected FL cell cultures by IEM. Throughout these experiments, no cytopathic effect (CPE) was discernible in the cultures.

Antigens, Viral↗
PubMed1981

Pharmacological studies on timiperone, a new neuroleptic drug Part II: General pharmacological properties.

General pharmacological properties of 4'-fluoro-4-[4-(2-thioxo-1-benzimidazolinyl) piperidino] butyrophenone (timiperone), a new neuroleptic drug, were compared with those of haloperidol. 1. Central nervous system: In behavioral observation, timiperone showed a typical neuroleptic profile at doses of 0.1 mg/kg p.o. and more (mice). The drug produced a moderate hypothermia at 10 mg/kg p.o. (rabbits), a mild increase in pain threshold at 3 mg/kg p.o. (mice and rats) and a slowing of cortical EEG at 1 mg/kg i.v. (cats). ED50 values of drug for the potentiation of ether and alcohol anesthesia were 0.34 and 0.22 mg/kg p.o., respectively (mice). Timiperone ahd neither an anticonvulsant activity at 30 mg/kg p.o. (mice) nor an effect on the spinal reflex at 1 mg/kg i.v. (cats). These effects of timiperone on the central nervous system were almost similar to those of haloperidol. 2. Respiratory and cardiovascular system: At dose of 0.03 mg/kg i.v. and more, timiperone produced transient increases in respiratory rate and regional arterial blood flow which were accompanied by a fall in blood pressure (dogs). Haloperidol had qualitatively similar effect, but was weaker than timiperone. Both drugs at high concentration (3X10-6 g/ml) exerted negative inotropic and chronotropic effect in isolated atrial preparations (guinea-pigs), and non-competitively antagonized the positive chronotropic action of isoprenaline. Atropine (2.5X10-7 g/ml) failed to modify the chronotropic action of timiperone (3X10-6 g/ml). 3. Autonomic nervous system: Timiperone at 0.1 mg/kg p.o. and haloperidol at 0.3 mg/kg p.o. induced a moderate miosis (rabbits) and antagonized blood responses to noradrenaline and acetylcholine (dogs). Both drugs at 1 mg/kg i.v. had no ganglion-blocking activity (cats). 4. Smooth muscle: In isolated guinea-pig ileum and vas deferens, timiperone and haloperidol (10-5 g/ml) antagonized the contractile responses of the muscles to various spasmogens, Both drugs at approximately 10-6 g/ml decreased spontaneous motility of the isolated rat uterus and inhibited the gastric secretion at 1 mg/kg i.p. (rats). At high doses, both drugs inhibited the gastrointestinal propulsion (mice), motility (dogs) and gastric emptying rate (rats), and had no damaging effect on the gastric mucosa (rats). 5. Skeletal muscle: At 0.1 mg/kg i.v., timiperone and haloperidol slightly enhanced twitch response of the anterior tibial muscle to electrical stimulation (rabbits). 6. Urine volume and urinary electrolytes: Timiperone and haloperidol showed a diuretic effect at 3 mg/kg p.o. whereas they inhibited urine output and electrolytes excretion at 30 mg/kg p.o. (rats).

Animals↗
PubMed1981

The implantation of a closed loop artificial beta cell in dogs.

1. Seven more diabetic dogs have been implanted with complete feedback artificial beta cell systems. 2. All of these units have functioned fairly well with maintenance of the animals in the process of extensive surgery but none have brought the animals under complete control. 3. The glucose sensors are at fault because they are insensitive to the glucose levels giving readings that appear functionally to be about half of true readings. 4. The defective function of the electrodes has been traced to the design of the electrodes which does not take the Km of glucose oxidase for oxygen into consideration. 5. Redesign of the electrodes by inclusion of a convertor for pO2 based on the reading of the reference electrodes leads to a reliable glucose reading. 6. It is recommended that all glucose electrodes which are based on glucose oxidase be redesigned to include an oxygen electrode to permit correction of the readings to account for the effect of local pO2 on their function.

Alloxan↗
PubMed1980

Further studies on the smooth-surfaced membranes isolated from rat brain.

The light and heavy smooth-surfaced membranes (LSM and HSM), which had densities corresponding to 1.08 M and 1.28 M sucrose, respectively, were isolated from rat brain and some of their biochemical properties were investigated. Both LSM and HSM showed high Na+,K+-ATPase activity and, in particular, in HSM the activity was four times (21.55 mumol/mg protein/h) higher than that of the brain homogenate. High 2',3'-cyclic nucleotide 3'-phosphodiesterase activity (293.4 mumol/mg protein/h) was characteristic of LSM. 5'-Nucleotidase and acetylcholinesterase activities were also higher in LSM than in HSM. SDS-polyacrylamide gel electrophoresis showed that LSM and HSM had many protein component and that low molecular weight proteins such as proteolipid protein and basic protein were almost absent, in contrast with myelin and myelin-like membrane. GM1 ganglioside constituted the major class of total ganglioside in both LSM and HSM. These biochemical findings suggested that LSM is a membrane that has not previously been described, or a membrane fraction related to the oligodendroglial plasma membrane.

2',3'-Cyclic-Nucleotide Phosphodiesterases↗