Search PubMed⌕ Search

Biomedical subjects

T Honma

Publications and source records attributed to T Honma.

At least 235 records · Page 13Linked to original sources
PubMed1977

Kinetic studies of the old yellow enzyme. I. The reaction mechanism of the enzyme with reduced nicotinamide adenine dinucleotide.

The reaction mechanism of old yellow enzyme (NADPH:(acceptor) oxidoreductase, EC 1.6.99.1) was kinetically investigated using NADH as substrate. The enzyme was reduced by NADH via a reaction intermediate which has a specific absorption spectrum. This intermediate decomposed to yield a reduced enzyme and NAD+ through an inrreversible first-order reaction step. The reduced enzyme was reoxidized by oxygen through a second-order reaction process. Individual values of elementary rate constants were measured and a computer simulation of the reaction process was carried out. No involvement of free radical of flavin semiquinone in the reaction process could be shown.

Aerobiosis↗
PubMed1977

[Effects of minor tranquilizers and neuroleptics on open-field behavior in rats (author's transl)].

Minor tranquilizers (diazepam, nitrazepam, oxazepam, bromazepam, medazepam, fludiazepam, meprobamate) at low doses increased ambulation score to 145 approximately 288% of control rats. Nitrazepam, diazepam and bromazepam which are potent, clinically prescribed minor tranquilizers increased the ambulation at lower doses than was seen with the other drugs. Fludiazepam and nitrazepam showed a maximum increase in ambulation at the same dose. Fludiazepam, nitrazepam and diazepam proved to have potent inhibitory effects on defecation. Trifluperidol, haloperidol and ID-4708 (a new butyrophenone derivative) and chlorpromazine when given at low doses reduced ambulation, while at higher doses defecation was inhibited. These four drugs reduced ambulation and elicited a recover in rates of defecation in methamphetamine treated rats. Clozapine, thioridazine and floropipamide inhibited defecation at nearly the same doses which reduced ambulation in rats not given the methamphetamine tratment. These three durugs reduced ambulation, but did not produce a recovery in the defecation rates in methamphetamine-treated rats. These results indicate that neuroleptics such as clozapine which rarely induce extrapyramidal side-effects when clinically prescribed, inhibit defecation at nearly the same doses which reduce ambulation. In methamphetamine-treated rats, haloperidol was 31 times more potent than chlorpromazine in inhibiting activity noted with ambulation. This ratio in open-field test was close to the ratio of potency of these drugs as antipsychotic clinically prescribed agents.

Animals↗
PubMed1976

Electron microscopic study on the pathogenesis of recurrent aphthous ulceration as compared to Behçet's syndrome.

In the prickle-cell layer of the oral epithelium of recurrent aphthous ulceration (RAU) the reticuloid cells with homogeneous, electron-lucent nuclei were attached to the degenerated prickle cells and ingested the cytoplasm of the prickle cells. The reticuloid cells came in contact with small lymphocytes, to which the immunologic information was transferred, inducing them to undergo blast transformation. Lymphoid cells, corresponding to T-cells, may produce a cytotoxic factor, since the prickle cells ultimately undergo degeneration. These changes are consistent with those of delayed hypersensitivity reactions. The cytoplasm of prickle cells apparently acts as an autoantigen. In Behçet's syndrome the macrophages were encountered in the epithelium. Other consequences were quite similar to those of RAU. The nucleus of the macrophage is more electron dense and has condensed chromatin along with the nuclear membrane. This can be a difference between Behçet's syndrome and RAU only at the initial stage of the diseases.

Behcet Syndrome↗
PubMed1976

Peripheral nerve conduction velocities in chain-saw operators.

The motor, sensory and mixed nerve conduction velocities of median and posterior tibial nerves were measured in seventeen forest workers engaged in chain-saw operation for 2 to 16 yr (mean 12 yr). The conduction velocities were significantly diminished in the distal part of the upper limb. The sensory nerve conduction velocities (SCV) of the median nerve at the part of the palm were slow in 12 workers; longer residual latency, in 6; and the mixed nerve conduction velocities slowed at the part of the forearm, in 6. From the relationships of the nerve conduction velocities to white finger attacks and electromyograms, it was assumed that vibration directly affected the distal part of the sensory and motor nerve fibers in the upper limbs, and that the diminished SCV in the palm was one of the most sensitive indices of vibration effects.

Adult↗
PubMed1976

Relationships between lead absorption and peripheral nerve conduction velocities in lead workers.

The motor sensory, and mixed nerve conduction velocities of median and posterior tibial nerves were measured in 39 lead workers whose blood lead (PbB) concentrations ranged from 2 to 73 mug/100 g with anaverage of 29 mug/100 g. The PbB concentrations significantly correlated with the maximal motor nerve conduction velocities (MCV) and mixed nerve conduction velocities (MNCV) of the median nerve in the forearm and with the MCV of the posterior tibial nerve. Erythrocyte delta-aminolevulinic acid dehydratase (ALAD) activity correlated similarly with the MCV and MNCV of the median nerve in the forearm, and the 24-hour urinary lead excretion following the intravenous administration of CaEDTA (20 mg/kg) (lead mobilization test) correlated with the MNCV. But no parameter correlated with the sensory nerve conduction velocities. By multiple regression analysis, a combination of the three parameters of lead absorption was found to correlate significantly with the MCV and MNCV of the median nerve in the forearm. The MCVs of the median and posterior tibial nerves in lead workers were significantly delayed in the PbB range of 29-73 mug/100 g (mean 45), in the lead mobilization test range from 173 to 3,540 mug/day (mean 973), and the ALAD activity range from 4.4 to 19.4 u. (mean 14.0), respectively.

Absorption↗
PubMed1975

Memory clip for intracranial aneurysm surgery. Technical note.

The authors have devised a malleable V-shaped removable clip with mechanical memory effect of shape memory. This clip is easily removed by heating part of it to 79 degrees to 107 degrees C, causing the closed clip to return to its original V shape.

Adult↗