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H Namba

Publications and source records attributed to H Namba.

At least 217 records · Page 12Linked to original sources
PubMed1987

The effects of mazindol on local cerebral glucose utilization in rats.

The effects of mazindol (1 mg or 10 mg/animal, p.o.) on local cerebral utilization of glucose were studied by the quantitative autoradiographic [14C]2-deoxyglucose method in conscious adult male rats. Significant increases in local cerebral utilization of glucose were observed 2 hr after administration of 10 mg of mazindol in 10 out of 37 anatomically discrete regions examined. These 10 areas included regions rich in dopaminergic receptors (substantia nigra, globus pallidus), and also regions with few dopaminergic receptors (cerebral cortex, thalamus, cerebellum). Only the habenular nucleus showed a significant decrease in utilization of glucose induced by the administration of 10 mg of mazindol. No significant changes in local cerebral utilization of glucose were observed following the administration of 1 mg of mazindol. The fact that the pattern of utilization of glucose observed in this study resembled that produced by apomorphine, a putative dopaminergic agonist, indicates that the pharmacological effects of mazindol are related to the dopaminergic system.

Animals↗
PubMed1987

Effects of insulin on local cerebral glucose utilization in the rat.

The effects of hyperinsulinemia on local cerebral glucose utilization were studied by the quantitative autoradiographic 2-[14C]deoxyglucose method in normal conscious rats under steady-state normoglycemic conditions. Hyperinsulinemia and a steady state of normoglycemia were achieved and maintained during the experimental period by a continuous intravenous (i.v.) infusion of insulin given simultaneously with a programmed i.v. infusion of D-glucose. Hyperinsulinemia under normoglycemic conditions did not change the average rate of glucose utilization in the brain as a whole, but significant increases in local glucose utilization were found selectively in the ventromedial, dorsomedial, and anterior hypothalamic nuclei. The results suggest that a known anatomical pathway linking the dorsomedial and anterior nuclei with the ventromedial nucleus of the hypothalamus may be physiologically activated in response to hyperinsulinemia.

Animals↗
PubMed1987

Effects of insulin on hexose transport across blood-brain barrier in normoglycemia.

The effects of insulin on 3-O-[14C]methylglucose transport across the blood-brain barrier (BBB) were studied in conscious rats under steady-state normoglycemic conditions. The [14C]methylglucose was infused intravenously at a constant rate, and animals were killed at various times between 5 and 30 min after the initiation of the infusion. The time course of the arterial plasma concentration of [14C]methylglucose was determined in timed arterial blood samples taken during the infusion. Local cerebral tissue concentrations of [14C]methylglucose at the time of killing were determined by quantitative autoradiography of brain sections. The rate constants for inward and outward transport of [14C]methylglucose across the BBB, K1, and k2, respectively, were estimated by a least-squares, best-fit of a kinetic equation to the measured time courses of plasma and tissue concentrations. K1 and k2 were reduced by an average of 24 and 31%, respectively, in gray matter and 7 and 16% in white matter from values estimated similarly in normal insulinemic control rats. The equilibrium distribution ratio, K1/k2, for [14C]methylglucose in brain increased by approximately 10-11% in the hyperinsulinemic animals. Because 3-O-[14C]methylglucose shares the same carrier that transports glucose and other hexoses across the BBB, these results suggest that hyperinsulinemia decreases the rate constants for transport but increases the distribution space for hexoses in brain. These effects are, however, quite small and are probably minor or negligible when compared with the major effects of insulin in other tissues.

3-O-Methylglucose↗
PubMed1984

Acute administration of high doses of estrogen increases glucose utilization throughout brain.

The effects of high intravenous doses of estradiol benzoate on local cerebral glucose utilization were studied by the [14C]2-deoxyglucose method in conscious ovariectomized adult rats. Statistically significant increases in glucose utilization averaging 20% were observed in 42 of 60 anatomically discrete regions of the estrogen-treated animals. The possible role of catechol estrogen, a potent inhibitor of catechol-O-methyltransferase, in these effects is considered.

Animals↗
PubMed1983

Blood reflux into anterior chamber after trabeculectomy.

A total of 90 eyes of 73 patients with various types of glaucoma underwent trabeculectomy and were under follow-up for a period ranging from 6 months to 8 years, with a mean of 32 months. Gonioscopy was performed using a Goldmann two-mirror contact lens; when at least one end of the internal trabeculectomy opening at the level of the trabecular tissue was free from iris adhesion the condition was designated as M1, and as M0 when the iris adhered to both ends of the opening. When the bottom of the trabeculectomy opening was visible, the condition was designated as H1, otherwise as H0. The condition of the trabeculectomy opening was then classified into three types, M1H1, M0H1 and M0H0; there were 40, 29 and 13 eyes, respectively, in each type, and in 8 eyes the condition was unclassifiable. On compression of the sclera with the base of the contact lens, a blood reflux into the anterior chamber from the vicinity of the cut ends of the Schlemm's canal was seen to occur in 22 out of 40 eyes with M1H1; this phenomenon was not observed in the other types. The incidence of the blood reflux was not correlated with the postoperative period, but intraocular pressure (IOP) control was significantly more successful in eyes with the blood reflux than those without this phenomenon. The IOP control was better in eyes with visible filtering bleb than in those without the bleb, and in eyes without the bleb, the IOP control was far superior in eyes with the blood reflux than in those without it. Tonography in selected eyes showed that the outflow facility was significantly higher in eyes with the blood reflux than in those without it. It was thought that aqueous filtration into the veins near the cut ends of the Schlemm's canal played a significant role in the IOP control after trabeculectomy.

Adult↗
PubMed1981

[Clinical results of synovectomy for rheumatoid wrist compared with the opposite side (author's transl)].

In the preoperative state, there were similar local findings on both sides of the wrist joint involved by rheumatoid arthritis in the roentgenogram. Synovectomy was performed on the one side of the wrist joint. Thirty six cases were compared with untreated controls and evaluated annually for eight years. From the roentgenological point of view, both wrists have almost similarly taken a turn for the worse. In spite of synovectomy, prevention of joint destruction has been unsuccessful. In the operated wrists it was due to ROM and pronation-supination which significantly improved wrist joint function. Although this improved level has been favorably maintained, there was a decline in dorsipalmar flexion and radio-ulnar flexion year after year. The results in the operated wrists were adequately better than the untreated wrists. Relief of pain was reported as follows: 94.4% : 2 years after the operation 84.8% : 4 years 81.3% : 6 years 80.0% : 8 years Synovectomy was followed by significantly less pain and satisfaction of treatment as reported by most patients. However analgetic effects of early synovectomy that was performed was ineffective and prevention of the destruction of joints roentgenologically met with negative results. The validity and the permanency of this synovectomy study was proved by the comparative evaluations made between the treated wrist joints and the untreated wrist joints, and also by the established clinical results.

Adult↗