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Biomedical subjects

N Oka

Publications and source records attributed to N Oka.

278 records · Page 16Linked to original sources
PubMedDate not supplied

Effects of chronic sulpiride-induced hyperprolactinemia on plasma testosterone and its responses to hCG in normal men.

To elucidate the effects of sulpiride-induced (300 mg daily) long-term (64 days) hyperprolactinemia on basal and hCG-stimulated plasma testosterone (T), hCG was given to five normal men five times at 2-week intervals (before sulpiride administration and at 2, 4, 6 and 8 weeks). Mean integrated hCG responses of plasma T did not change significantly as compared with baseline. However, mean (+/- SEM) basal plasma levels of T decreased significantly (P less than 0.05) from 1011 +/- 148 ng/dl to 852 +/- 13 at 2 weeks, 520 +/- 53 at 4 weeks, 572 +/- 137 at 6 weeks and 554 +/- 140 at 8 weeks. These results suggest that sulpiride-induced hyperprolactinemia (73.8 ng/ml, the average of mean values obtained at 2, 4, 6 and 8 weeks) for 64 days does not suppress secretion of T in response to hCG in spite of a decrease in basal plasma T concentrations. It is unlikely that the low concentrations of plasma T are due to direct effects of hyperprolactinemia on the testis.

Adult↗
PubMedDate not supplied

Angioarchitecture in experimental hydrocephalus.

The angioarchitecture of microcorrosion casts in 12 hydrocephalic rats and 5 normal control rats was investigated by using scanning electron microscopy to observe the changes of the vascular bed in the cerebral mantle in hydrocephalus. Reduction in the number and caliber of the capillaries in the white matter was the most remarkable change in the hydrocephalic rats. This change increased in proportion to the severity of hydrocephalus. A similar change was observed in the basal ganglia. The change in the cortical capillaries was mild, but the cortical 'palisade' pattern had disappeared in some cases. Three-dimensional consideration of the angioarchitecture by using microvascular casts compared with microangiographic technique in rat hydrocephalus was discussed.

Animals↗
PubMedDate not supplied

Measurement of regional blood flow using hydrogen gas generated by electrolysis.

Electrochemically generated hydrogen gas was used to measure local blood flow by Stosseck et al. The data obtained by their method, however, did not correlate well with those obtained by hydrogen inhalation. We have modified the equation proposed by Stosseck, prolonging the stimulus duration in order to increase the amount of hydrogen generated. In dog white matter the resulting clearance curves were formed to be monoexponential both in the living animal as well as after circulatory arrest when all the clearance is by diffusion away from the electrode. The values calculated by our equation correlated well with those obtained by hydrogen inhalation.

Animals↗
PubMedDate not supplied

Density of sympathetic nerve terminals in human superficial temporal arteries: potassium permanganate fixation and monoamine oxidase histochemistry.

The density of sympathetic nerve terminals in human superficial temporal arteries from 5 cases at intra- and extracranial bypass surgery was examined with two histochemical methods, one with potassium permanganate fixation and the other with the new monoamine oxidase staining technique. By potassium permanganate fixation, small cored vesicles containing fibers of noradrenergic nerve terminals made up 29.2% of all nerve fibers in the adventitia. The monoamine oxidase-containing nerves in the adventitia made up 31.4%. According to this study, sympathetic nerve terminal density in human superficial temporal arteries was assumed to consist of approximately 30% of all adventitial nerve terminals. In periadventitial nerve bundles, some unmyelinated axons contained monoamine oxidase activity. Thus, staining is considered to be useful in demonstrating the periadventitial and intervaricose fibers as well as the nerve terminals of sympathetic nerves in human cerebral arteries.

Fixatives↗
PubMedDate not supplied

[A patient with Crow-Fukase syndrome associated with pulmonary plasmacytoma].

We here reported a 54-year-old female patient with Crow-Fukase syndrome associated with pulmonary plasmacytoma. She was found to have scattered tumor in 1990. Although the tumor had slowly grown for the last 10 years, she showed no clinical symptoms. Numbness and weakness of lower extremities began in June 1999, and she was referred to Kyoto University Hospital on Oct. 21 1999 for evaluation of progressive symptoms. She had skin pigmentation, edema of the lower extremities, lymphadenopathy, muscle weakness and sensory disturbance in a glove-and-stocking distribution. Serological examination showed monoclonal IgG-lambda gammopathy. Serum vascular endothelial growth factor (VEGF) was markedly elevated. Microscopic studies on biopsied sural nerve demonstrated mild decrease of myelinated fibers. Immunohistochemically, the pulmonary tumor was defined as an IgG (lambda type) plasmacytoma. After treatment with melphalan-prednisolone therapy, the neurological symptoms improved along with decrease of serum VEGF levels as well as the size of pulmonary plasmacytoma. This is the first report of a patient with Crow-Fukase syndrome associated with pulmonary plasmacytoma. This case suggests that growth of pulmonary plasmacytoma might have played an important role in the overproduction of VEGF and thus development of Crow-Fukase syndrome.

Antineoplastic Agents, Alkylating↗