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Biomedical subjects

K Ota

Publications and source records attributed to K Ota.

At least 649 records · Page 36Linked to original sources
PubMed1984

The role of central alpha 1- and alpha 2-adrenoceptors in the regulation of vasopressin release and the cardiovascular system.

In order to investigate the role of central alpha 1- and alpha 2-adrenoceptors in the control of vasopressin (ADH) release and the cardiovascular system, norepinephrine (NE) (1.4 microgram/kg), methoxamine (1.4 microgram/kg), yohimbine (60 micrograms/kg), and prazosin (40 micrograms/kg) were administered via the cerebral ventricles in urethane-chloralose-anesthetized dogs after morphine sedation (n = 42). In the control study 0.9% saline was administered. NE resulted in a significant fall in blood pressure, heart rate, and ADH release. Methoxamine tended to activate the cardiovascular system, but did not affect the release of ADH significantly. Prazosin decreased blood pressure significantly with a significant rise in heart rate and ADH release. Pretreatment with prazosin did not block significantly the effect of NE on blood pressure, heart rate, and ADH release. Yohimbine did not affect the cardiovascular system and ADH release significantly. Pretreatment with yohimbine completely blocked the effect of NE on ADH release, and brought about a slight rise in blood pressure and heart rate. In none of the experiments could changes in ADH release be attributed to changes in plasma osmolality. These results indicate that central alpha 1-adrenoceptors might act to activate the cardiovascular system, but have no effects on ADH release in anesthetized dogs. On the other hand, central alpha 2-adrenoceptors might act to reduce ADH release and to depress the cardiovascular system.

Animals↗
PubMed1984

The effects of postural changes on ADH release and the renal handling of sodium and water in patient with idiopathic edema.

In order to investigate the role of ADH and the renal handling of sodium and water in patients with idiopathic edema, 21 patients were subjected to acute oral water load tests. Although a normal water diuresis was observed in al patients in supine posture, it was markedly impaired in upright posture with significant decreases in sodium, free water, and osmolar clearances. In particular, two patients exhibited the continuous production of concentrated urine after the water load in upright posture. The fractional reabsorption of sodium at the proximal tubules was significantly increased in upright posture, while the glomerular filtration rate did not change significantly. The constricting of both legs with elastic bandages tended to improve the water diuresis in upright posture, suggesting that the pooling of blood into the lower legs might be contributing to the formation of idiopathic edema. The patients showed normal osmoregulation of ADH release in supine, but not in upright posture: the suppression of ADH release in upright posture was only transient or incomplete despite a sufficient fall in plasma osmolality following the water load. Thus, both an increase in renal sodium reabsorption and the insufficient suppression of ADH release in upright posture might contribute to the retention of body fluid in patients with idiopathic edema.

Adolescent↗
PubMed1984

[Acute cardiotoxicity of anthracyclines--analysis by using Holter ECG].

To investigate the detailed acute cardiotoxicity of the anthracycline antibiotics, adriamycin (ADM) and a tetrahydropyranyl derivative (THP-ADM), Holter ECG was recorded and some of the electrocardiographic parameters were analyzed. The basic rhythm was sinus rhythm in many cases except only one case which developed intermittent atrial fibrillation after the administration of ADM. No effect on the specialized conduction system was observed in either ADM or TH-PADM. In relation to the supraventricular premature beat, no increase of the pre-existing supraventricular extrasystole and fresh appearance of the supraventricular extrasystole were observed after the administration of these drugs. On the other hand, the ventricular premature beat was tended to increase after ADM administration, and the mode of appearance of the ventricular extrasystole was very dangerous and life-threatening. For example, short-run type and R on T type ventricular extrasystole were recorded. THP-ADM induced no significant increase of the ventricular extrasystole. The developed ST-T changes were seen after the administration of these drugs, but the patients complained neither the symptoms of heart failure nor stenocardia. In conclusion. THP-ADM had less cardiotoxicity than ADM.

Adolescent↗
PubMed1984

Five antigens on human T cells detected by mouse monoclonal antibodies.

Five antigen systems were defined by the monoclonal antibodies (MoAb) produced against mature T cells. The antigens recognized were grouped into two categories based on the antigen distribution on T cells. (a) Tp 120 [mol. wt 120 kilodaltons (120kD)] and Tp40 (40kD), these are on most peripheral T cells, but not on any other cell lineages, i.e. pan-T antigen. (b) Ts32 (32kD), Ts145 (145kD) and TsA (not determined), these antigens are present only on certain populations of peripheral T cells, i.e., T subset antigen. Among these five, Ts145 and TsA are probably novel T cell antigens. Cell surface phenotypes of leukaemias and lymphomas were typed with these MoAb. Ia like antigen negative, null cell type acute lymphocytic leukaemia (Ia- null ALL) are Tp40+, suggesting that this type of ALL belongs to a T cell lineage. T cell ALL (T-ALL) and lymphoblastic lymphoma (LL) were both Tp40+, Ts32+, TsA+ and a half of the cases were Tp120+, but the expression of Tp40 was stronger on LL cells. Mature T cell (T2) lymphoma and adult T cell leukaemia (ATL) were Tp120+, TsA+, while Tp40 was weakly expressed on only one third of the cases. These MoAb were found to be useful to estimate the origin of various T cell malignancies.

Animals↗
PubMed1984

[Antitumor activities and mechanisms of action of harringtonine and homoharringtonine].

The antitumor activities and the mechanisms of action of harringtonine and homoharringtonine, alkaloids isolated from cephalotaxus hainanensis Li, were compared to those of vincristine. The results obtained were as follows: Harringtonine and homoharringtonine Significantly inhibited the growth of L1210 cells in culture. The IC50 values were similar to that of vincristine. Harringtonine and homoharringtonine had little effects on changes in the DNA histograms of FL cells at any concentrations, which suggesting that these drugs prolong the duration of each phase of the cell cycle evenly. Harringtonine and homoharringtonine had only a minor effect in arresting P388 cells in mitosis. Harringtonine significantly inhibited the DNA synthesis of P388 leukemia cells in culture, while vincristine weakly inhibited RNA and DNA synthesis. The successive treatment with harringtonine and homoharringtonine were as effective as the successive treatment with vincristine against P388 and L1210 leukemia, while both drugs were ineffective against Lewis lung carcinoma.

Alkaloids↗
PubMed1984

[Immunotherapy with bestatin for acute non-lymphocytic leukemia (ANLL) in adults].

A cooperative randomized controlled study of immunotherapy with bestatin for ANLL in adults was conducted at 16 institutions. After complete remissions were induced and consolidated with combination chemotherapy, patients were randomly allocated into two groups, one with maintenance chemotherapy alone (C) and the other with the same maintenance chemotherapy plus bestatin (B). Out of 115 patients entered in this study, 101 (B): 48, C: 53) were eligible. The 50% remission duration was 20.4 months for B compared with 11.1 months for C, and comparable 50% survivals were 33.3 and 18.9 months respectively. B had significantly longer remission duration and survival time than C. Remission duration and survival time in patients under 49 years of age were not significantly different in both groups. But in patients over 50 years of age B had significantly longer remission duration and survival time than C. Side effects of bestatin were mild and transitional. These data suggest the usefulness of bestatin for the treatment of adult acute non-lymphocytic leukemia.

Acute Disease↗