Acta Medica Okayama volume35 issue1

In order to elucidate the specific thyrotropic area in the hypothalamus, thyrotropin releasing hormone (TRH) content and concentration were measured in discrete hypothalamic nuclei and areas after triiodothyronine (T3) administration (T3 10 micrograms/rat/day for 6 days), thyroidectomy (TX) and acute cold exposure in male rats. In th TX and T3 groups, serum TSH levels were significantly increased in TX group and markedly decreased in T3 and TX with T3 groups as compared to the sham operated control group (Sham). TX produced a slight but nonsignificant decrease in TRH content in most of the hypothalamic nuclei examined as compared with the Sham group. However, a significant increase in TRH contents was seen in the anterior hypothalamic nucleus (AHN), median eminence (ME) and posterior pituitary (PP) in TX with T3 group as compared to the rats with only TX. In the acute cold stress experiments, serum TSH levels were elevated from 15 to 30 min of 4 degrees C exposure. Together with these peripheral changes, TRH content and concentration in the suprachiasmatic nucleus (SC) were increased significantly at 15 min and had returned to the normal level by 30 min after 4 degrees C cold exposure. However, in the paraventricular nucleus (PV) and dorsal premammillary nucleus (PMD), marked decrease in TRH concentrations were observed with this stress. Therefore, 1) decreased TSH release in TX rats treated with T3 was induced by the block of TRH release from the AHN and ME as compared with the TX group, and 2) elevated serum TSH levels in 4 degrees C cold stress might be induced by the release of TRH from the PMD and PV. These experiments demonstrate that the specific hypothalamic area for TSH release was located in some of the anterior and posterior hypothalamic nuclei and in the ME.

The distribution of corticotropin releasing factor (CRF) and arginine vasopressin (AVP) in hypothalamic nuclei were examined in control and estrogen-treated female rats. CRF activity was measured using monolayer cultured rat anterior pituitary cells and AVP by radioimmunoassay. Hypothalamic nuclei were punched out according to the method of Palkovits. The distribution of CRF activity in 5 different hypothalamic nuclei was similar to that of AVP in intact female rats. CRF activity in hypothalamic nuclei, pituitary ACTH content and plasma ACTH levels in estrogen-treated rats were not significantly different from those in control rats. However, significant elevation of AVP content was observed in the supraoptic and paraventricular nuclei of estrogen-treated rats. These results indicate that CRF and AVP are distributed in similar hypothalamic nuclei, but that they are not identical.

Chromosome studies were conducted on two patients with adult T-cell leukemia. In both patients, a marker chromosome 14q+ and a structural change involving chromosome 1 with trisomy of the q arm were found in peripheral blood leukocytes. The 14q+ marker chromosome had resulted from translocation from #5p in one patient and #5q in the other patient. The present and previous studies suggest that the donor chromosomes involved in the 14q+ translocation are variable. This indicates that the 14q+ marker chromosome rather than the donor chromosome is intimately related with adult T-cell leukemia.

A perifusion method has been developed using rat hypothalamo-neurohypophyseal system (HNS) or neural lobe to investigate the control mechanism of arginine vasopressin (AVP) release. A specific radioimmunoassay (RIA) for AVP was developed to measure AVP in perifusion medium employing anti-AVP serum which was obtained by immunizing rabbits. At a final dilution of 1/12,000, the antiserum showed less than 0.66 and 0.01% cross reactivity with lysine-vasopressin and oxytocin, respectively. But it did not cross reacted with other peptide hormones. The lowest detectable level of vasopressin was 0.5 pg/tube. The intra-assay coefficient of variation averaged 10.4%. The dilution curve of perifused medium was well paralled to the standard curve of AVP assay. AVP release from HNS or neural lobe gradually declined to the stable level in 90-120 min after the initiation of perifusion. Good repeatability of the AVP release from neural lobe was recognized by repeated stimulation with 10 min perifusion of 60 mM KCl at every 60 min. HNS released AVP in dose related manner to the osmotic challenge of sodium or glucose, and AVP release was stimulated from HNS by prostaglandin E2, but not by dopamine. These results show that the perifusion methods using AVP-RIA is a useful method to examine the AVP release from HNS or neural lobe.

The distribution of corticotropin releasing factor (CRF) and arginine vasopressin (AVP) in hypothalamic nuclei were examined in control and estrogen-treated female rats. CRF activity was measured using monolayer cultured rat anterior pituitary cells and AVP by radioimmunoassay. Hypothalamic nuclei were punched out according to the method of Palkovits. The distribution of CRF activity in 5 different hypothalamic nuclei was similar to that of AVP in intact female rats. CRF activity in hypothalamic nuclei, pituitary ACTH content and plasma ACTH levels in estrogen-treated rats were not significantly different from those in control rats. However, significant elevation of AVP content was observed in the supraoptic and paraventricular nuclei of estrogen-treated rats. These results indicate that CRF and AVP are distributed in similar hypothalamic nuclei, but that they are not identical.

Rat liver and simian virus 40 (SV40) chromatin were reconstituted in vitro under physiological conditions of ionic strength and temperature. The nucleosome assembly under the conditions was mediated in the presence of chromatin extracts, rich in nicking-closing activity, from rat liver or cultured CV-1 cells. The frequency of nucleosome assembly on DNA was dependent on both the incubation time and the weight ratio of histone to DNA. The regulatory effects of host cellular histones on the transcription of SV40 DNA were investigated by using reconstituted SV40 chromatin containing or lacking histone H1. The cellular histones composing the chromatin were prepared from permissive CV-1 cells. Transcription of chromatin was analyzed in vitro using Escherichia coli DNA-dependent RNA polymerase. The rate of incorporation of ribonucleoside triphosphates into RNA synthesized on SV40 chromatin containing Hl as the template was 5 to 10% of the rate for RNA synthesized on supercoiled SV40 DNA. The rate of incorporation for SV40 chromatin lacking Hl was approximately 40 to 50% of that for SV40 DNA. RNA products transcribed from both these chromatin and SV40 DNA were fairly homogeneous 16 to 28S species with several identical peaks.

Thirteen patients exhibited a communicating hydrocephalus following subarachnoid hemorrhage secondary to ruptured intracranial aneurysms and were treated with shunt procedures. The interval between subarachnoid hemorrhage and surgery averaged 9 weeks. Seven of the patients showed improvement. The prognostic value for surgical management was evaluated on the basis of three different diagnostic examinations (computed tomography(CT), cisternography and constant infusion test). A correct diagnosis was obtained in 78 per cent in cisternography, and 63 per cent in infusion test and CT. All patients responding to surgery showed a typical pattern in cisternography, consisting of ventricular retention of radiopharmaceutical tracer for 48 h or longer in association with no radioactivity over the cerebral hemispheres. The constant infusion test correlated well with typical cisternographic patterns. CT is useful in demonstrating pathophysiological changes in hydrocephalus. Periventricular hypodensity was visible in patients with normal or slightly elevated intracranial pressure, accompanied by fairly rapid deterioration. All of them responded well to shunting. In most cases which benefited from the shunt, the postoperative CT showed not only normal-sized ventricles but also marked regression of the hypodensity over a short period.