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Biomedical subjects

Y Okabe

Publications and source records attributed to Y Okabe.

At least 109 records · Page 6Linked to original sources
PubMed1987

Role of the glucopyranose ring in the elicitation of feeding.

To relate the structural characteristics of the glucose pyranose ring to feeding elicitation, biochemically and structurally similar glucose analogues were investigated to determine if they could elicit short- or long-term effects on food intake in rats. Testing solutions were infused once into unrestrained and unanesthetised rats through a chronically indwelling cannula in the third ventricle. D-Glucose markedly decreased meal size in doses from 6 to 24 mumol, but it's epimers, D-mannose, D-allose and D-galactose, did not affect food intake. Among the glucose analogues modified at C-2, rats treated with 12 mumol D-glucosamine ate a much larger size of meal than those with 12 mumol halogenglucoses or 24 mumol 2-deoxy-D-glucose, while 2-fluoro-2-deoxy-D-glucose with 2-chloro-2-deoxy-D-glucose induced a more potent feeding than 2-deoxyglucose. Glucosamine also induced hyperglycaemia, but did not affect plasma insulin. Activity of glucose, sensitive neurons in the lateral hypothalamus was increased by electro-osmotic application of 2-deoxyglucose or glucosamine, and the reciprocity was observed on neurons of the ventromedial hypothalamus. One-aminoglucose (beta-D-glucopyranosylamine), which is an aminoglucose analogue modified on C-1, increased meal size and more potently prolonged the duration of the meal compared to 1-deoxyglucose (1,5-anhydroglucitol). Together with the behavioural and structural characteristics of glucose analogues, a hydroxyl group on C-1 or C-2 is involved in feeding elicitation. The magnitude of the effect can be partly explained by the chemical concept of 'inductive effect'.

Animals↗
PubMed1986

Thyrotropin releasing hormone levels in human cerebrospinal fluid in various neurologic diseases.

Thyrotropin releasing hormone (TRH) in the human cerebrospinal fluid (CSF) of 102 patients with non-neurologic and neurologic diseases was measured by a specific TRH radioimmunoassay. TRH levels in CSF were 17.6 +/- 3.4 pg/ml (mean +/- SE) in non-neurologic diseases. TRH levels in CSF were significantly elevated in cases of spinal cord tumor and multiple sclerosis (acute phase). Elevated TRH levels in CSF were decreased in these diseases by operation or prednisolone treatment, respectively. From these data, it is suggested that TRH is present in the human CSF and that measurement of TRH levels in CSF may be a useful indicator of the activity of certain neurologic diseases.

Adolescent↗
PubMed1986

Changes in intracellular K+ and Na+ ion concentrations during cell growth and differentiation.

We compared intracellular K+ and Na+ ion concentrations during cell growth and differentiation of a mouse myeloid leukemia M1 cell line. Cells undergoing mitosis had higher K+ concentrations than quiescent cells. Treatment with a K+ channel blocker and furosemide enhanced cell growth and produced a slight increase in the intracellular K+ concentration. Treatment with reagents that reduced the intracellular K+ concentration stopped cell growth. Induction of differentiation in this cell line produced a decrease in the K+ concentration, which always was accompanied by an increase in the Na+ concentration. Treatment with ouabain, which decreased the intracellular K+ concentration, did not, however, induce differentiation in the M1 cell line. The data suggest that cell growth and differentiation in the M1 cells are accompanied by changes in the intracellular K+ and Na+ concentrations but that the changes in the contents of these monovalent cations do not necessarily induce differentiation in this cell line.

Animals↗
PubMed1985

Administration of D-glucosamine into the third cerebroventricle induced feeding accompanied by hyperglycemia in rats.

D-glucosamine, 2-amino-2-deoxy-D-glucose, is known to be an endogenous glucose analogue and to antagonize glucose uptake and metabolism. The present experiments were aimed to clarify effects of glucosamine and related chemical substances on ingestive behavior, as well as its direct effects on hypothalamic neurons. Infusion of 24 mumole glucosamine into the third cerebroventricle induced feeding within 30 min in 5 rats out of 7 tested, accompanied by increased ambulatory activity. No periprandial drinking was observed. Plasma glucose level increased, peaking at 30 min after the injection. Plasma insulin level tended to increase, but not significantly. Electrophoretic application of glucosamine activated glucose-sensitive neurons in the lateral hypothalamus and suppressed glucoreceptors in the ventromedial hypothalamus. These facts, together with other reported results, suggest that glucosamine can modulate physiological feeding and that carbon 2 of the glucose molecule is important in feeding modulation by glucose analogues.

Animals↗
PubMed1982

Malignant lymphoma of the parotid gland.

A case of malignant lymphoma of the parotid gland was described. A 15-year-old male developed a mass which was a firm and non-tender. The patient underwent a superficial parotidectomy with preservation of the facial nerve. The tumor was a grey, soft mass, 3 X 4 X 4 cm in size. On microscopic examination, the tumor was intraglandular lymph node with invasion of salivary gland tissue. The tumor cells were seen between acini and ducts. A diagnosis of lymphosarcoma, prolymphocytic, nodular type was made according to the WHO's classification system and the patient was refered for radiation therapy. Further investigations, including radio-isotope scanning of liver, spleen and bone and a biopsy of bone marrow revealed no sign of the disease. The patient was treated with 5380R of cobalt irradiation and in follow-up of a one year's duration there was no recurrence. Our case fulfilled the criteria which was represented by Hyman and Wolff and we reviewed the literature of this condition.

Adolescent↗