Search PubMed⌕ Search

Biomedical subjects

M Ohno

Publications and source records attributed to M Ohno.

At least 577 records · Page 32Linked to original sources
PubMed1985

Effects of long use of a beta-blocker, carteolol, on exercise hemodynamics in hypertensives.

The symptom limited maximal exercise was performed by a supine bicycle ergometer before and 12 weeks after oral carteolol therapy in 10 patients with essential hypertension of WHO Stage 1 and 2. At rest, arterial blood pressure (BP) and venous pressure (VP) significantly declined after therapy, while heart rate (HR), cardiac index (CI), stroke index (SI) and systemic vascular resistance (SVR) were not significantly changed. The maximal exercise work of post-therapy was similar to that of pre-therapy in 9 patients and increased in one. When compared with the pre-therapy values at each work load of exercise, carteolol caused significant decreases in systolic BP, mean BP, HR and CI, and a significant increase in SVR, while SI and VP were not significantly changed. Plasma levels of renin activity, aldosterone, and catecholamines were not altered by carteolol throughout the study at rest and with exercise. It may be concluded that the inhibition of HR increase by carteolol results in a reduced cardiac output during moderate and severe exercise and then suppresses the elevation of BP, so that carteolol makes it possible to achieve more exercise with less cardiac work.

Administration, Oral↗
PubMed1985

Mycinamicins, new macrolide antibiotics. IX. Chemical ionization mass spectral studies on mycinamicins.

Chemical ionization (CI) mass spectra of new macrolide antibiotics, mycinamicins are reported. Protonated molecules (MH+) are observed as base peaks in the CI mass spectra of all components. Fragmentations are mainly restricted to the glycosidic linkages and the resulting aglycone and sugar-derived ions appear regularly in their mass spectra. Moreover, characteristic fragment ions involving carbon-carbon bond fission are found in the CI mass spectra of the epoxyenone-containing components, mycinamicins I (1) and II (2). The mechanism for the formation of the ion species is also discussed.

Anti-Bacterial Agents↗
PubMed1985

[Effect of calcium entry blocker, nimodipine, on the cerebral function and metabolic recovery following experimental cerebral ischemia].

Ischemic deporalization of cell membranes is associated with a precipitous influx of calcium from the extracellular to the intracellular compartment, and it is suggested that increased intracellular calcium in ischemic brain leads to an activation of phospholipase and to increase of the concentration of free fatty acids, in particular arachidonic acid, with energy depletion. The objective of the present study is to test whether calcium entry blocker, nimodipine, prevent increase of free fatty acids and metabolic disturbances during ischemic period, and promote functional and metabolic recovery after recirculation. Severe forebrain ischemia in rats was induced by four-vessel occlusion with reducing the systolic arterial pressure to 100 mmHg. After forebrain ischemia had been maintained for 30 minutes, recirculation was started by removal of the arterial clamps of bilateral common carotid arteries and by increasing systemic blood pressure to the preischemic level. The EEG was continuously recorded from gold-coated screws inserted bilaterally in the parietal bones with the tips in extradural position, against a reference inserted prefrontal bone. Analysis of power spectrum of EEG activity was done by Berg Fourier Analyser. The brain were frozen in situ with liquid nitrogen before, during and after ischemia and then chiselled out during irrigation with liquid nitrogen. Concentrations of ATP, ADP, AMP and free fatty acids in brain tissue were determined with high performance liquid chromatography. Nimodipine, 10 micrograms/kg, was given intravenously 2-3 minutes before induction of ischemia, and an infusion of 1 microgram/kg/min was continued during ischemic and postischemic periods.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1985

[HLA antigen on the trophoblast of normal pregnancy].

The mechanism of fetal survival as a semiallograft in the uterus remains to be clarified. In this context, the expression of HLA antigen on the trophoblast which stands between the mother and the fetus is the main problem, because HLA antigen plays an important role in immunological reaction to an allograft. For this purpose, 41 pregnant uteri (6-18 weeks of gestation) were examined immunohistochemically (avidin-biotin-peroxidase complex method) using monoclonal antibodies to HLA antigens. Troma 1, a rat monoclonal antibody, was used as a trophoblast marker in immunohistochemical studies. The results were as follows: HLA-A,B,C is not expressed on syncytiotrophoblast and villous cytotrophoblast. HLA-A,B,C is expressed on nonvillous cytotrophoblast which exists in cytotrophoblastic cell column, cytotrophoblastic shell, and endometrium. HLA-DR is not expressed on any trophoblast. The absence of HLA antigen on syncytiotrophoblast and villous cytotrophoblast seems to be essential for the survival of the fetus. But it is proved that some trophoblasts express HLA-A,B,C on their cell surface and they are adjacent to endometrial cells or maternal blood. From these findings, it seems that fetal HLA antigen might be recognized by the mother and there might be an exquisite immune escape mechanism in decidua.

Antibodies, Monoclonal↗
PubMed1984

Identification of transfer RNA suppressors in Escherichia coli. III. Ochre suppressors of lysine tRNA.

Transducing phages of lambda carrying suppressors, lysT (Su+ beta), supG and and supL, were isolated in vivo. Upon infection with each of these phages, the production of tRNALys and tRNAVal1 was markedly enhanced. Fingerprint analysis of these tRNAs revealed that they consisted of normal tRNALys, mutant tRNALys and tRNAVal1 in equimolar ratios. The mutant tRNALys carried a single-base alteration at the anticodon, from 5'-UUU-3' to 5'-UUA-3', which makes it an ochre suppressor. DNA sequence analysis of the entire transducing fragment (730 base-pairs) of lambda pSu+ beta revealed that three tRNA genes are tightly clustered within a transcription unit in the following order; i.e. promoter-(48 base-pairs)-wild-type tRNALys-(132 base-pairs)-tRNAVal1-(2 base-pairs)-Su+ beta tRNALys-. In wild-type bacteria there are two identical tRNALys genes in one operon. Although we have shown that in Su+ beta it is the distal tRNALys that has been mutated to the ochre suppressor by a single base change at the anticodon (U36 to A36), we have not determined which of the two genes bears the supG or the supL mutation. The sequences following both tRNALys genes are highly homologous: both are about 100 base-pairs long and both terminate with an 18 base-pair sequence homologous to the last 18 bases of each tRNA. The sequences of tRNALys and tRNAVal1 are also very similar. Thus, including the 3'-portions of these tRNA genes, the 18 base-pair sequence is more or less periodically repeated five times in the DNA sequence.

Bacteriophage lambda↗
PubMed1984

Responses of cat vestibular neurons to stimulation of the frontal cortex.

To study the neural basis for the regulation of vestibulocollic reflexes during voluntary head movements, the effects of stimulation of the precruciate cortex near the presylvian sulcus (neck area of the motor cortex) and the frontal eye fields (FEF) on vestibular neurons were studied in cerebellectomized cats anesthetized with alpha chloralose. Neurons were recorded in the medial and descending vestibular nuclei and antidromically identified from C1. Stimulation of the FEF and precruciate cortex fired 29 and 13% of neurons that did not exhibit spontaneous activity. About 80% of spontaneously discharging neurons were influenced by stimulation of either of the two. Stimulation of the precruciate cortex or FEF suppressed or facilitated labyrinthine evoked monosynaptic activation of vestibulospinal neurons, suggesting that the frontal cortical neurons have the properties to regulate the vestibulocollic reflexes.

Animals↗
PubMed1984

Postprandial release of neurotensin-like immunoreactivity and its mechanism.

The effects of various ingested materials on plasma neurotensin-like immunoreactivity (NTLI) in humans were investigated using a newly developed, specific radioimmunoassay. Plasma NTLI was determined after its extraction with acid/acetone (recovery 77 +/- 4%). The intraassay and interassay coefficients of variation were 3.6% and 8.9%, respectively. The plasma concentration of human NTLI in normal subjects was 5.6 +/- 2.9 pmol/l and showed no significant sex difference. Ingestion of a test meal (150 g of Campbell's condensed meat soup) caused a biphasic rise in plasma NTLI from a basal level of 5.7 +/- 1.0 pmol/l to 10.8 +/- 1.2 pmol/l after 30 min and 9.6 +/- 1.1 pmol/l after 120 min. Ingestion of 5.5 g fat resulted in a biphasic rise in plasma NTLI from a basal level of 4.8 +/- 0.3 pmol/l to 8.9 +/- 0.3 pmol/l after 15 min and 11.9 +/- 0.4 pmol/l after 90 min. When 100-150 mg of ileal mucosa was perfused with a solution of 2 mEq/l fatty acids, 1 mM or 5 mM sodium taurocholate or 154 mM sodium bicarbonate (NaHCO3), the release of NTLI from the mucosa into the perfusate was 2.3-fold, 4.3-fold and 7.5-fold, respectively, over the base level. These results indicate that NTLI release is stimulated by ingestions of meat soup and fat and that NTLI present in the human ileum is released by the direct actions of solutions of fatty acid, sodium taurocholate, and NaHCO3 on the ileal mucosa. These findings strongly suggest that neurotensin (NT) has a physiological role in gut physiology.

Adult↗
PubMed1984

Is it necessary to adjust the replacement dose of thyroid hormone to the season in patients with hypothyroidism?

Hypothalamo-pituitary-thyroid activity varies with the temperature of the environment; we therefore measured variables involved with thyroid function in summer and winter in normal controls and in patients with primary hypothyroidism. All seven patients had impalpable thyroid glands and had received a set replacement dose of thyroxine for over a year. In the patients, serum T3 and FT4 levels were slightly but significantly lower in winter, and TSH levels and delta TSH at 30 minutes in the TRH tests were significantly higher. In the controls, there were no significant differences between summer and winter in these values. These findings suggest that the dose required for replacement of thyroid hormone in patients with hypothyroidism may be higher in winter than in summer.

Adult↗
PubMed1984

Neuroanatomical study of somatomotor cortex in microcephalic mice induced by cytosine arabinoside.

Somatomotor cortex of mice with microcephaly induced by DNA polymerase inhibitor cytosine arabinoside (Ara-C), has been studied with a modified Golgi-Cox staining and a HRP retrograde tracing method. Microcephalic mice were prepared by prenatal injections of cytosine arabinoside on days 13.5 and 14.5 of pregnancy. Cytoarchitectonically, the cerebral cortices of adult microcephalic mice are characterized by atypical pyramidal cells with abnormal dendrites and irregular patterns of cellular lamination. Semiquantitative analyses of the abnormality of dendrites in Golgi-Cox preparation indicate that both the degree and direction of ramification are severely affected in Ara-C treated mice. In adult control cerebrum, original neurons of corticospinal tract labeled after HRP injection into the lumbar cord were situated in layer V. In the microcephalic brains, however, HRP labeled neurons, some of which had abnormal polarity, were scattered throughout all layers. This HRP study for corticospinal tract neurons also confirms the irregular pattern of the cortex in which only three layers are recognized.

Afferent Pathways↗
PubMed1984

Interaction of Trimeresurus flavoviridis phospholipase A2 and its fragment with calcium ion.

Dimeric T. flavoviridis phospholipase A2 has been studied in terms of the interaction with essential Ca2+ by equilibrium gel filtration, ultraviolet difference spectroscopy, fluorescence measurements, and chemical modifications with p-bromophenacyl bromide. The subunit bound to Ca2+ with a 1:1 molar ratio and no cooperative binding was observed. The hypochromic effect produced upon the binding of Ca2+ is due to perturbation of (a) specific tryptophan residue(s) located in the vicinity of the active site and appears to be characteristic of this enzyme. On the basis of the pH dependence of the dissociation constants, it has been found that the alpha-amino group (pKa 8.7) controls the binding of Ca2+. Deprotonation of the alpha-amino group is possibly accompanied by conformational transition to the active form which is able to bind Ca2+. This is in contrast to the case of bovine pancreatic phospholipase A2 in which Asp-49 (pKa 5.2) is responsible for the metal ion binding (Fleer et al. (1981) Eur. J. Biochem. 113, 283-288). Des-octapeptide(1-8)-phospholipase A2 (L-fragment) was found to be capable of binding Ca2+ under the control of a group with a pKa of 7.6. This pKa value was similar to an apparent pKa of 7.5 determined for the histidine residue in the active site of the native enzyme by way of p-bromophenacyl bromide modification. It appears that the N-terminal (octapeptide) sequence affects the binding mode of Ca2+, possibly because of conformational transition arising from its removal. The reinvestigation showed that the N-terminal octapeptide sequence is Gly-Leu-Trp-Gln-Phe-Glu-Asn-Met.

Animals↗
PubMed1984

Acquisition of native structure from reduced Trimeresurus flavoviridis phospholipase A2.

Oxidation of reduced T. flavoviridis phospholipase A2 under suitable conditions resulted in recovery of its active, native structure. The oxidized product was eluted at the same positions as native phospholipase A2 on reserved phase column and DEAE-Toyopearl 650M column chromatographies. The native and regenerated proteins were also identical in mobility on polyacrylamide gel electrophoresis and in circular dichroism spectra. Des-octapeptide(1-8)-phospholipase A2 (L-fragment), which shows only greatly reduced activity, was reduced and oxidized but no effective reformation of the native structure was found, indicating that the entire sequence is required for efficient reorganization.

Animals↗