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Biomedical subjects

K Imai

Publications and source records attributed to K Imai.

At least 1,585 records · Page 88Linked to original sources
PubMed1975

PH dependence of the Adair constants of human hemoglobin. Nonuniform contribution of successive oxygen bindings to the alkaline Bohr effect.

In order to solve the problem of an apparent discrepancy between the pH variance of oxygen equilibrium curve and the linear relation between the number of released Bohr protons and the degree of ligation, precise oxygen equilibrium curves of human hemoglobin were determined at a number of pH values from 6.5 to 8.8. From the equilibrium data individual steps (Adair constants), ki (i equals 1, 2, 3, 4), were obtained and the number of Bohr protons (deltaHi+) released on the ith stage of oxygenation was estimated. The pH dependence of k4 was very small, while the other ks strongly depended on pH over the pH range examined. As a consequence, the contribution of each step of oxygen binding to the alkaline Bohr effect nonuniform: deltaH4 was very small compared with deltaH1+, deltaH2+, and deltaH3+. In spite of this, calcuation has shown that the fractional number of released protons is essentially proportional to fractional oxygen saturation because of cooperative effects in hemoglobin. Thus, the present study indicates that the linear relationship between the fractional number of released protons and the degree of ligation, as obtained from titration experiments, is not necessarily incompatible with the pH variance of the shape of the oxygen equilibrium curve. The nonuniform pH depencence of the Adair constants implies that the two-state allosteric model of Monod, J., Wyman, J., and Changeus, J.P. (1965) J. Mol. Biol. 12, 88-118 is not adequate to describe the heterotropic effect caused by protons.

Hemoglobins↗
PubMed1975

Fluorimetric assay of dopamine, norepinephrine and their 3-O-methyl metabolites by using fluorescamine.

Fluorescamine was subjected to reaction with dopamine and norepinephrine (catecholamines) and with 3-methoxytyramine and normetanephrine (3-methyl metabolites of catecholamines) in phosphate or borate buffer. Catecholamines gave the highest fluorescent intensity at pH 8.0 in phosphate buffer but lower fluorescence in borate buffer. The fluorophores produced in phosphate or borate buffer were the same but the fluorescence intensities were suppressed in borate buffer. The dopamine and norepinephrine fluorophores were separated by high-pressure liquid chromatography on Hitachi 3011 gel with methanol-0.10 M Tris buffer of pH 8.0 (7:3). They were measurable at the 100-pmole level. The metabolites were also measurable by the same chromatography. By using methanol-0.15 M borate buffer of pH 8.0, cate-chol-O-methyltransferase activity might be assayed.

Boric Acids↗
PubMed1975

Daunorubicin, cytosine arabinoside, 6-mercaptopurine riboside, and prednisolone (DCMP) combination chemotherapy for acute myelogenous leukemia in adults.

Thirty-seven adults with acute myelogenous leukemia (AML) were treated with a combination of daunorubicin, cytosine arabinoside, 6-mercaptopurine riboside, and prednisolone (DCMP) for remission induction. Twenty-three of 37 patients (62.2%) achieved complete remission, three, partial remission and 11, failure. Patients with prior therapy responded as well as patients without it. The median survival time of the patients who received DCMP for their initial remission induction therapy was 10.3 months and that of the patients who obtained complete remission was 17 months. Complete remission occurred in 21 out of 28 patients (75%) less than 40 years old but in only two out of nine patients (22.2%) more than 40 years old. The most common toxic effects were severe myelosuppression and liver function abnormalities. DCMP therapy is an effective remission induction chemotherapy for adults with AML.

Adolescent↗
PubMed1975

[Oxidant-drug induced hemolytic anemia in dogs].

Heinz body anemia was induced in dogs by consecutive oral administration of 200 mg/kg and 60 mg/kg of aminopyrine, 200 mg/kg of phenacetin and 5 mg/kg of acetylphenylhydrazine, for either 8 or 16 weeks. Biochemical analysis showed a decrease of haptoglobin in plasma and reduced-glutathion in red blood cells in association with anemia. Hematologically, an increase in osmotic fragility and cell volume of erythrocytes were also noted. Pathological examination revealed marked erythrophagia and hemosiderosis in the reticuloendothelial system of treated animals. A new anti-inflammatory analgesic 31252-S (3-(1-hydroxy-2-piperidinoethyl)-5-phenylisoxazole citrate) was also tested for the hemolytic effects in dogs. Blood analyses revealed a slight increase of Heinz bodies and a decrease of reduced-glutathion in red blood cells without anemia. These findings suggest that 31252-S have weaker oxidant properties than those of aminopyrine and phenacetin. The present studies showed that the concentration of reduced-glutathion in red blood cells of non-treated dogs was approximately 50% lower than that of the erythrocytes of normal human beings. This finding appeared to correspond with high susceptibility of red blood cells to hemolytic effects of oxidant-drugs in dogs.

Aminopyrine↗
PubMed1975

Effect of estrogen administration on activities of testosterone 5alpha-reductase, alkaline phosphatase and arginase in the ventral and the dorsolateral prostates of rats.

Daily treatment with 5 or 500 mug of estradiol benzoate of male adult rats for 7 days did not change the activity of testosterone 5alpha-reductase in the ventral prostate, while the activity decreased slightly in the dorsolateral prostate. The activity of alkaline phosphatase was increased by 60% over the respective control in the ventral prostate from rats treated with the larger dose of estrogen, but the estrogen treatment did not affect the alkaline phosphatase activity in the dorsolateral prostate. On the contrary, the estrogen treatment evoked three-fold elevation in the arginase activity of the dorsolateral prostate in contrast to the decreased arginase activity in the ventral prostate following estrogen administration. From these results, it was concluded that the alterations in some enzyme activity of the ventral and the dorsolateral prostates evoked by estrogen treatment were different from those observed in the respective lobes from castrated animals, although both estrogen administration and castration induced atrophy of the tissue. Furthermore, it might be also worth-while to mention that the ventral and the dorsolateral prostates of rats responded in a different manner to estrogen administered.

3-Oxo-5-alpha-Steroid 4-Dehydrogenase↗
PubMed1975

[Biphasic (ulcer-forming and ulcer-preventing) effect of adrenaline in rats].

Adrenaline-induced gastric ulceration was studied in rats. Adrenaline in high doses caused gastric ulcer, which was completely blocked by pretreatment with alpha-blockers (phenoxybenzamine, dibenamine), but not by pretreatment with propranolol or atropine, nor by vagotomy, hypophysectomy or adrenalectomy. After successive administration of adrenaline, once daily for 7 days, however, no gastric ulcer was observed. Recovery from the ulcerogenic action of adrenaline was seen after 4 weeks withdrawal. Pretreatment with a small dose of adrenaline inhibited the ulcerogenic action of a high dose of adrenaline. Pretreatment with reserpine, pyrogallol or iproniazid inhibited the action of adrenaline. It is concluded that adrenaline has a biphasic effect on gastric ulceration, the ulcerogenic action is due to its alpha-action and antiulcerogenic effect is due to development of tachyphylaxis.

Adrenalectomy↗
PubMed1975

Surface antigenic specificities of human thymus-derived lymphocytes.

Surface antigenic specificities of human thymus-derived (T) lymphocytes were studied by cytotoxicity tests using a heterologous rabbit anti-human thymus serum. This serum showed higher cytotoxic titres on thymocytes by comparison with peripheral lymphocytes. After proper absorption the antiserum was non-toxic for chronic lymphatic leukaemia cells, but lysed the majority of thymocytes. It also lysed some of peripheral lymphocytes, corresponding to those lymphocytes which bound sheep erythrocytes (E) but not erythrocyte-antibody-complement complexes (EAC). Pretreatment of lymphocytes with the absorbed antiserum and complement completely abrogated rosette formation with E but spared EAC-binding lymphocytes. It also eliminated their reactivity to phytohaemagglutinin and concanavalin A. These findings indicate that the absorbed serum causes selective lysis of T cells. The results obtained from quantitative absorption studies suggest that a certain loss of T-cell antigens is brought about during the differentiation of thymocytes into peripheral T cells.

Animals↗
PubMed1975

Histochemical studies on the distribution of some enzymes concerned with carbohydrate metabolism in the locus ceruleus, nucleus tractus mesencephalicus n. trigemini, nucleus dorsalis n. vagi and nucleus n. hypoglossi of the rat.

Detailed histochemical studies have been conducted on the distribution of hexokinase, amylophosphorylase, aldolase, lactic dehydrogenase, succinic dehydrogenase and glucose-6-phosphate dehydrogenase in every component of the locus ceruleus, nucleus tractus mesencephalicus n. trigemini, nucleus dorsalis n. vagi and nucleus n. hypoglossi of the wistar strain rats. The locus ceruleus and nucleus dorsalis n. vagi which are considered to be belong to "exceptional nuclei" showed mild activity in the nerve cell bodies and strong activity in the surrounding glia cell for the hexokinase reaction. But, the nucleus tractus mesencephalicus n. trigemini and nucleus n. hypoglossi considered to be "usual nuclei" revealed strong activity in the nerve cell bodies and glia cells for the hexokinase reaction, however, glia cells did not show the tendency to surround the nerve cells in these nuclei. On the basis of the present findings, the glia cells may get their energy source from glucose in the circulating blood, and they may be energy donators to the nerve cells in the "exceptional nuclei" whereas the nerve cells may get their energy source directly from glucose in the circulating blood in the "usual nuclei". The former 2 nuclei showed low level activity of succinic dehydrogenase. These findings may indicate that the locus ceruleus and nucleus dorsalis n. vagi belong to the conception "exceptional nuclei" in this respect. However, the Embden-Meyerhof-Parnas (EMP) pathway was dominant in the locus ceruleus, while the WARBURG-DICKENS pathway (hexose monophosphate shunt = HMP shunt) was dominant in the nucleus dorsalis n. vagi in the present study. This descrepancy may strongly suggest that the locus ceruleus is distinctly different from the nucleus dorsalis n. vagi concerning the carbohydrate metabolism, though both nuclei are involved on the same conception "exceptional nuclei". The latter 2 nuclei (the nucleus tractus mesencephalicus n. trigemini and the nucleus n. hypoglossi) considered to be "usual nuclei" in 3 ways as that nerve cells get energy source directly from glucose in the circulating blood, that the 2 nuclei are equipped with enzymes involved in the EMP pathway and the HMP shunt to the same degree, and that they are rich in the tricarboxylic acid (TCA) cycle. The nucleus tractus mesencephalicus n. trigemini revealed considerably variable reactions for the hexokinase, aldolase, glucose-6-phosphate dehydrogenase and lactic dehydrogenase in the present study.

Animals↗