Biomedical subjects
Publications and source records attributed to K Kitahama.
Using immunohistochemical techniques, the distribution of ACTH 25-39 immunoreactive perikarya and fibers was studied in the newborn rat. Perikarya and fibers were demonstrated on day 1 after birth in the diencephalon, mesencephalon, pons and medulla. However, the amount of material increased rapidly from the first to third day of postnatal development.
Monoamine oxidase (MAO) histochemistry combined with retrograde horseradish peroxidase tracing of neurons demonstrated that MAO-containing neurons in the tuberal, caudal and postmamillary caudal magnocellular nuclei of the hypothalamus project to various cerebral cortices.
Using a recently developed monoamine oxidase (MAO) histochemical technique, we show the existence of MAO-containing neurons in the cat hypothalamus. In conjunction with retrograde tracer technique with horseradish peroxidase, we further demonstrate that virtually all posterior hypothalamic neurons projecting directly to the occipital cortex contain MAO, an amine catabolizing enzyme.
The sleep-waking cycle was studied in two strains of mice during continuous exposure over 3 weeks to an ambient temperature of 34 degrees C or 10 degrees C. As compared to the 25 degrees C control period, C57BL/6 mice showed at 34 degrees C a mean increase of 25% in slow-wave sleep (SWS) particularly during the night. Paradoxical sleep (PS) was also increased by 58% during the exposure period particularly during the night and this resulted from an increase in the number of PS episodes. At 10 degrees C SWS was decreased by 9% only during the first week of exposure, whereas PS was reduced by 24% throughout due to a decrease in the number of PS episodes, although their duration increased. The acrophase of the circadian rhythms was not affected by the changes in ambient temperature. In the BALB/c strain at 34 degrees C SWS and PS were increased only during the first week by 13% and 77%, respectively. At 10 degrees C SWS was decreased by 7% throughout and PS was decreased by 36% due to a reduction in the number of PS phases during the light period. On returning to 25 degrees C, a rebound in PS confirmed the PS deprivation in the cold in both strains.
Using a combined retrograde HRP and immunohistochemical technique in the cat, we have demonstrated the existence of direct descending projections of the ACTH immunoreactive neurons in the arcuate nucleus of the hypothalamus to the pontine tegmentum, especially, to the nucleus locus coeruleus alpha.
Using immunohistochemical techniques, we demonstrated oxytocin (OT) and vasopressin (AVP) neurons in the cat hypothalamus. The OT immunoreactive neurons were found mainly in the paraventricular nucleus, supraoptic nucleus and dorsal accessory group located lateral to the fornix. In addition to these hypothalamic structures, the AVP immunoreactive neurons were observed in the suprachiasmatic nucleus, ventral accessory group located in the retrochiasmatic area and lateral accessory group, dorsal to the supraoptic nucleus caudally, and ventral to the medial part of the internal capsule rostrally. We further demonstrated a different localization of the OT and AVP immunoreactive neurons in the paraventricular and supraoptic nuclei.
In chronic pontine cats without hypothalamo-hypophysis, daily subcutaneous or intraventricular injection of total extracts of Bovine neuro-intermediate lobe increases both survival and quantity of paradoxical sleep, while synthetic Lysine vasopressin, Oxytocin or ACTH have no effect. Chronic pontine cats with "isolated hypophysis" have a longer survival and a more significant amount of paradoxical sleep than those without hypothalamo-hypophysis. Factor(s) liberated by pars intermedia are very likely to be responsible for the increase of PS since only pars intermedia remains functional in the "isolated hypophysis" as shown by immunocytochemical controls.
Through combined retrograde labeling with HRP and serotonin immunohistochemistry, we have demonstrated that ventral and caudal hypothalamic neurons, both non-immunoreactive and immunoreactive to serotonin after administration of 5-hydroxytryptophane, give rise to direct ascending projections to the entire cerebral cortex as well as direct descending projections to the nucleus locus coeruleus alpha in the pontine tegmentum. A retrograde double labeling method with fluorescent dyes further suggested that the population of ascending hypothalamic neurons is different from that of descending ones.
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Cefoxitin was administered to a total of 17 patients with intractable bronchopulmonary infections who had failed to respond to other conventional antibiotics, and the following results were obtained. (1) The clinical response, except 1 patient classified as evaluation impossible, was excellent in 3 patients, good in 10 and fair in 3 with an efficacy rate of 81.3%. (2) An improvement rate of more than 70% was observed in the findings of body temperature, dyspnea, colour of sputum, WBC and CRP. (3) There was no subjective nor objective side effects attributable to cefoxitin. In view of the results stated above, we have concluded that cefoxitin is a useful antibiotic for the treatment of intractable bronchopulmonary infections.
Experiments are reported which show that 1 mg/kg of d-methylamphetamine HCl induced hyperactivity in pigmented strains (C57BR, C57BL/6, and SEC) and hypoactivity or no change in albino strains (BALB/c, A, and AKR) of mice. In F1 hybrids, the B6 genotype was partially dominant over BR and C, and BR over C. In animals back-crossed to C parents widespread distributions with two peaks were obtained in control experiments, and amphetamine induced hyperactivity in 38% of the albino population, and hypoactivity or no significant change in 45% of the pigmented one. This genetic study indicates that genes influencing locomotor activity are independent from those influencing amphetamine sensitivity. From results obtained in back-crosses and C57BL/6-c2J mice, the albino gene does not seem to be involved in the hypoactive effect of amphetamine.
d-Methylamphetamine (1--4 mg/kg) induced wakefulness for 3--5 h followed by paradoxical sleep (PS) rebound in C57BR, C57BL/6, and BALB/c mice. Slow-wave sleep (SWS) and PS suppression time were proportional to the given dose and different among strains. It was also dependent on the time of injection. Later PS rebound was significant in C57 strains, and in certain cases greater than PS loss, whereas rebound was small in BALB/c mice and PS loss was not completely compensated.
Effects of instrumental and pharmacological deprivation of sleep on Y-maze learning have been studied in two inbred strains of mice (C57BR/cd/Orl and C57BL/6/Orl), having identical sleep rhythms, but mainly differing in their ability to learn. Administration of alpha-methyl-DOPA (100 mg/kg) provokes complete suppression of paradoxical sleep (PS) for 9-11 h. Injection immediately after each training session over the first 5 days caused a delay in acquisition of an active avoidance task in C57BR mice. Treated C57BL/6 mice exhibited a significant facilitation of acquisition. Similar results were obtained by instrumental deprivation of sleep for 10 h.
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The effects of alpha-methyl-Dopa at several dose levels on waking-sleep cycle of 175 mice from two inbred strains (C57BR and C57BL/6) have been studied. The results showed that each dose (25, 50, 100, 200 and 400 mg/kg), of alpha-methyl-Dopa completely suppresses paradoxical sleep (PS), after a period of sedation. Duration of PS inhibition varied as a function of dose, time of injection, and strain of mice. Using a multiple injection schedule of one injection per day for 5 consecutive days, there was suppression of nocturnal PS followed at the 4th day by rebound during day light hours.