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Biomedical subjects

Y Shinohara

Publications and source records attributed to Y Shinohara.

At least 19 recordsLinked to original sources

Determination of plasma testosterone by mass fragmentography using testosterone-19-d3 as an internal standard. Comparison with radioimmunoassay.

Analytical procedures for the measurement of testosterone by mass fragmentography (MF) using trideuterated testosterone (testosterone-19,19,19-d3) are described. For the calculation of plasma testosterone, peak height ratios were measured by MF performed on the molecular ions of the TFA derivative of testosterone (m/e 480) and testosterone-19,19,19-d3 (m/e 483). The sensitivity of the method was judged from the lower limit of detection of the mass spectrometer which was at 10 pg. For the measurement of the precision, the inter- and intra-assay coefficients of variation (C.V.) were calculated by using a pooled plasma sample; they were 3.15% and 1.79%, respectively. The specificity was investigated by the use of 5 alpha-dihydrotestosterone and the MF method was found to afford a highly selective technique. These results obtained by MF have been compared with the results obtained by a radioimmunoassay method.

Gas Chromatography-Mass Spectrometry

Tyrosinemia.

A case of tyrosinemia in a three-month-old boy is presented. The patient appeared jaundiced initially with markedly elevated levels of serum tyrosine and a positive Millon-reacting urine. Jaundice persisted and hepatosplenomegaly gradually increased. He died due to liver failure on the 51st day after admission. At autopsy, the liver showed the features of severe giant cell hepatitis including giant cell formation, fibrosis and bile retention. The pancreas and the brain showed characteristic postmortem findings as previously reported in patients with tyrosinemia.

Amino Acid Metabolism, Inborn Errors

[Renal failure].

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Humans

Sequential quantitative studies on hyperplastic nodules in the liver of rats treated with carcinogenic chemicals.

Sequential quantitative analyses were made of hyperplastic liver nodules induced by treating male Fischer rats first with diethylnitrosamine (DEN) and then with N-(2-fluorenyl)acetamide (2-FAA), alpha-isomer of 1,2-3,4,5,6-hexachlorocyclohexane (alpha-BHC), or phenobarbital. The test rats were injected ip with 200 mg/kg body weight of DEN, given basal diet containing 2-FAA, alpha-BHC, or phenobarbital from week 2 to 12, and subjected to partial hepatectomy at the end of week 3. From week 6, significantly higher percentage areas of hyperplastic nodules per unit area of liver were found in all experimental groups than in the control group. From week 8, significantly more hyperplastic nodules were found in all experimental groups than in the control group. Continuous administration of alpha-BHC or phenobarbital for 12 weeks with partial hepatectomy did not induce hyperplastic nodules. Continuous administration of 2-FAA did induce hyperplastic nodules, but the percentage areas and number of these nodules were significantly lower than in rats injected with DEN and then given 2-FAA orally, with partial hepatectomy.

2-Acetylaminofluorene

Effects of cholinesterase inhibitors on the spasmogenic action of acetate esters on rat uterus.

Acetate esters, such as phenyl acetate and aspirin, induced atropine-sensitive contractions of isolated uterus only when choline was present. These contractions were selectively and reversibly inhibited by carbamate-type cholinesterase inhibitors, such as neostigmine and eserine, and quaternary ammonium compounds, such as tetraethylammonium and decamethonium. After treatment with organophosphorus cholinesterase inhibitors, such as di-isopropyl fluorophosphate and tetraethyl pyrophosphate, the uterus failed to respond to the acetate esters, even when high concentrations of choline were present. The inhibition of the response of the uterus by organophosphates was effectively removed by pyridine-2-aldoxime methiodide. Pretreatment of the uterus with neostigmine or simultaneous addition of high concentrations of quaternary ammonium compounds prevented the inhibition by organophosphates. The inhibition produced by neostigmine was also reduced by simultaneous addition of quaternary ammonium compounds. These findings suggest that some esterase having an anionic site and an esteratic site, probably cholinesterase, may mediate in the uterine contractions induced by acetate esters in the presence of choline, and that inhibition by organophosphates, carbamates and quaternary ammonium compounds of cholinesterase activity in the preparation may impede the initiation of contractions by the acetate esters in the presence of choline.

Acetates

Isolation and biological characterization of a measles virus-like agent from the brain of an autopsied case of subacute sclerosing panencephalitis (SSPE).

Isolation of a cytopathic agent causing formation of syncytial giant cells in co-cultivated Vero cells from the brain of an autopsied case of subacute sclerosing panencephalitis (SSPE) is reported. The syncytia usually autolyzed from the center after growing to 1 to 2 mm in diameter and then detached from the culture vessels, and finally made macroscopically recognizable round plaques on the monolayer under liquid overlay. The agent was identified serologically as an agent related to measles virus, by both immunofluorescent tests and plaque reduction tests using anti-measles sera. However, the infected cells did not produce either virions or hemagglutinin, and failed to show hemadsorption and hemolysis of African green monkey red cells even after the 55th passage through Vero cells. Newborn mice, adult mice and hamsters showed neurologic signs after intracerebral inoculations of the infected cells, and most of them died from acute encephalitis. Guinea pigs were unsusceptible. From the brain of the animals with neurologic signs, a similar agent to the inoculated one was recovered. The new isolate appears to be a strain closely related to measles virus on the basis of serology, and was designated as SSPE-"Kitaken-1" strain.

Adolescent

Toxic neuropathy as a complication of thiophenicol therapy.

Two cases with sensory neuropathy due to thiophenicol therapy are reported. Thiophenicol neuropathy is hitherto unreported in literature published in English. Neurological manifestations of these cases were similar to those of chloramphenicol neuropathy, but rather marked impairment of position sense in the lower extremities was characteristic. Thiophenicol neuropathy reported in Japanese literature was reviewed and it is concluded that thiophenicol administered in large doses (70-150 g) or for long periods (more than 3-5 months) appeared to have a toxic effect on the nervous system.

Adult

Effect of N-(3,5-dichlorophenyl)succinimide on the histological pattern and incidence of kidney tumors induced by streptozotocin rats.

The effect of the nephrotoxic substance, N-(3,5-dichlorophenyl)succinimide, on the histological pattern and incidence of kidney tumors induced by streptozotocin in rats was studied. In groups administered streptozotocin alone or in combination with nicotinamide, the histological pattern and the incidence of kidney tumors in rats were similar; renal cell tumors developed in 1 of 9 rats (11.1%) and in 2 of 17 rats (11.8%), respectively. However, post-treatment with N-(3,5-dichlorophenyl)succinimide increased the induction of epithelial tumors by streptozotocin, and embryonal cell tumors were also induced nearly as frequently. Administration of nicotinamide alone did not result in the development of kidney tumors.

Adenoma, Islet Cell