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Biomedical subjects

M Kishi

Publications and source records attributed to M Kishi.

At least 145 records · Page 8Linked to original sources
PubMed1989

[Prostatic tissue and fluid levels of lomefloxacin (NY-198)].

The concentration of Lomefloxacin (NY-198), a new quinolone, in human prostatic tissue and fluid was examined. Lomefloxacin was concentrated in prostatic gland and the mean ratios of prostatic tissue levels to serum levels (P/S) were 1.39-1.83 during 2 to 6 hrs after administration. Concerning prostatic fluid concentrations, there were no significant differences between healthy volunteers and patients with chronic prostatitis. The mean ratios of prostatic fluid levels to serum levels (Pf/S) were 0.36-0.77 during 1 to 4 hrs after administration. The concentration of Lomefloxacin in the prostatic tissue and fluid is high enough to eradicate the majority of pathogens causing bacterial prostatitis.

4-Quinolones↗
PubMed1989

[Intracellular recording of myotonia in mdx mouse and the effect of Ca antagonist in myotonia].

Bulfield and others found X-linked muscular dystrophic (mdx) mouse by screening C57 BL/10 mice. The serum CK and PK are high in mdx mice, and they develop muscle degeneration 10-15 days after birth. The regeneration is vigorous in mdx mice and almost all the muscle fibers are replaced by regenerated fibers by 60 days after birth. Although mdx mice have been developed as a model for X-linked muscular dystrophy we have found that myotonic bursts are recorded when a glass microelectrode is inserted into the muscle fibers of hemidiaphragm preparations of mdx mice. Insertion myotonia is ceased by addition of the Na channel blocker tetrotoxin. Myotonia is not reduced, nor ceased by lowering the extracellular Ca to 1/15 of the volume of ordinary Tyrode's solution. Calcium antagonist, nicardipine at the dose of 10(-7), and 10(-6)M/L do not reduce myotonic bursts. Higher dose of nicardipine up to 2 x 10(-5)M/L abolished myotonic bursts. These results indicate that myotonic bursts are related to muscle membrane abnormalities, and each action potential occurs through Na channel, but not through Ca channel Higher dose of calcium antagonist can abolish myotonia by affecting Na channel in addition to their primary effects of Ca channel. The clinical effects of the Ca antagonist for myotonia was reported in one study. Since previous medications for myotonia including quinine HCl, procaine amide, diphenylhydantoin, and carbamazepine have some side effects such as tinnitus, headache, nausea, cardiac blocks, and bone marrow suppression, Ca antagonist may be used as a safe therapeutic drug for myotonia.

Animals↗
PubMed1988

Characteristics of taurine transport system and its developmental pattern in mouse cerebral cortical neurons in primary culture.

Developmental patterns and pharmacological and biochemical properties of taurine transport system were investigated using developing primary cultured neurons prepared from mouse cerebral cortex by trypsin treatment. [3H]Taurine was incorporated into neurons via a high-affinity transport system of which the Km value as well as the Vmax value increased during neuronal development in vitro. This transport system was also inhibited by sodium withdrawal from incubation medium and exposures for 15 h to several metabolic inhibitors such as 2,4-dinitrophenol and monoiodoacetate. In addition, [3H]taurine uptake in both neurons cultured for 3 and 14 days was competitively inhibited by beta-alanine, guanidinoethanesulfonate and hypotaurine. Cysteic acid and cysteine sulfinic acid, metabolic intermediates produced in the process of taurine biosynthesis in the brain from cysteine, induced significant reductions in [3H]taurine uptake in both types of cultured neurons, while cysteine, isethionic acid, cysteamine and cystamine exhibited no alterations in [3H]taurine transport. Moreover, non-competitive inhibition of [3H]taurine uptake by cysteic acid was observed in both neurons. These results clearly indicate that taurine uptake was mediated by the sodium- and energy-dependent transport system with high affinity in 14-day-old neurons as well as neurons cultured for 3 days and that both the Km and Vmax values of this transport system increase during neuronal development in vitro. The results described above suggest that the decrease in taurine content observed in developing brain is unlikely to be due to alteration in the capacity of the taurine transport system during neuronal development.

Amino Acids↗
PubMed1988

An autopsy case of mitochondrial encephalomyopathy: biochemical and electron microscopic studies of the brain.

A 29-year-old single woman had recurrent stroke-like episodes. She developed loss of consciousness, myoclonic seizures, and lactic acidosis. She died at the age of 30. A muscle biopsy study revealed mitochondrial myopathy, and the postmortem biochemical analysis demonstrated decreased cytochrome c oxidase activity in the skeletal muscles by 20% of normal control. The brain had multiple ischemic lesions in the cerebral cortex without major vascular occlusions. We present this case as an autopsy case of mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) with a partial deficiency of cytochrome c oxidase. The analytical electron microscopic study of the calcified small vessels in the globus pallidus revealed increased calcium, phosphorus and iron. No accumulation of chromium, nickel or zinc was noted in this case, which was different from the previously reported cases of basal ganglia calcification.

Adult↗
PubMed1988

Micronucleus tests in mice on 39 food additives and eight miscellaneous chemicals.

A total of 47 chemical substances including 32 synthetic food additives, seven additives from natural sources, three trihalogenated methanes, two fluoro-compounds for dental use, one insecticide, and two other compounds were subjected to the micronucleus test in mice. Five compounds, i.e. chlorine dioxide, maltol, potassium bromate, sodium chlorite and sodium dehydroacetate, were found to induce micronuclei after a single ip injection. Potassium bromate, sodium chlorite and sodium dehydroacetate were tested further by oral administration, and potassium bromate showed a clearly positive result. Almost all the compounds which were negative with the single treatment were additionally tested by four or five multiple treatments, but none showed any indication of micronucleus induction.

Animals↗
PubMed1988

A repeat sequence, GGGTTA, is shared by DNA of human herpesvirus 6 and Marek's disease virus.

Some regions of the genomes of human B-lymphotrophic virus (HBLV), also designated as human herpesvirus 6, and Marek's disease virus were found to hybridize to each other under moderate to stringent conditions, scoring from 10 to 30% base-pair mismatch. Nucleotide sequence analysis showed that a 6-base-pair repetitive sequence, GGGTTA (DR2), present in the IRS-IRL junction region of the Marek's disease virus genome, was also reiterated in the HBLV genome. The function(s) of such a sequence is unknown, but this is the first report of homology between HBLV and a nonhuman herpesvirus.

Animals↗
PubMed1987

Development of gamma-aminobutyric acid (GABA)ergic neurons in cerebral cortical neurons in primary culture.

The developmental patterns of gamma-aminobutyric acid (GABA)ergic neurons in primary culture obtained from the neopallium of 15-day-old fetus of mouse were investigated in terms of morphological features, GABA metabolism and GABA receptor binding. Morphological investigations revealed that these cells possessed typical features of neurons and the formation of synapses was detected at 10 days after the inoculation. During neuronal growth on polylysine surfaces, GABA contents and activity of GABA transaminase (GABA-T) showed a progressive increase in the time of culture. Similarly, L-glutamic acid decarboxylase (GAD) showed a progressive elevation during neuronal development in vitro, which corresponded well with the change in immunoreactivity to anti-GAD examined immunohistochemically. In addition, the high K+-evoked release of [3H]GABA also showed an enhancement during the growth in vitro. The numbers of binding sites (Bmax) for [3H]muscimol and [3H]flunitrazepam (FLN) also showed increases with the time of incubation, although affinity (Kd) to the labeled ligands did not show any noticeable changes. Moreover, it was observed that [3H]FLN binding was enhanced by GABA even in neurons cultured for 7 days. These results indicate that cerebral cortical neurons in primary culture possess GABA biosynthesizing and degrading systems including a high-affinity uptake mechanism for GABA. The present results also indicate that these cells possess synaptic contacts as well as GABAA receptors coupled with benzodiazepine receptor from a relatively early stage of cellular development.

4-Aminobutyrate Transaminase↗
PubMed1987

Computed tomography and angiography in MELAS (mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes); report of 3 cases.

Among mitochondrial encephalomyopathies, MELAS (mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes, Pavlakis et al. 1983) is recognized as a distinct syndrome characterized by generalized convulsions and recurrent stroke-like episodes. The neuroradiological findings of three patients with MELAS are reported here. Retrospective review shows that MELAS should be included in the differential diagnosis of infarct-like lesions of the cerebrum.

Acidosis, Lactic↗
PubMed1986

Biopharmaceutical studies on hydantoin derivatives. V. Pharmacokinetics and pharmacodynamics of 5,5-diphenylhydantoin and 1-benzenesulfonyl-5,5-diphenylhydantoin.

Disposition of 1-benzenesulfonyl-5,5-diphenylhydantoin (II) having a potent anti-inflammatory activity was compared with that of 5,5-diphenylhydantoin (I), an antiepileptic drug, in order to elucidate whether the pharmacodynamic difference between them can be explained by their physicochemical and pharmacokinetic properties. After oral administration of I-14C to rats, radioactivity was distributed in all tissues including the brain, whereas after II-14C administration, the concentrations of radioactivity in most tissues were lower than those in plasma. The results were consistent with the finding obtained by whole-body autoradiography which revealed that after oral administration of II-14C to rats, radioactivity was not transferred into brain but was significantly transferred into inflamed tissues. Brain/plasma concentration ratio of I was about 1.3, whereas that of II was about 0.05. Plasma protein binding of I having pKa value of 8.30 was about 88%, whereas that of II having pKa value of 4.89 was about 99%. The changes in physicochemical properties due to introduction of a benzenesulfonyl group into the hydantoin ring may be responsible for the difference in the disposition between I and II. When II was cerebroventricularly administered to mice, it showed a potent anti-convulsant activity against maximal electroshock seizure, the activity being comparable to that for I. This indicates that the earlier failure to demonstrate the activity of II in a routine screening test for antiepileptic drugs was due to the inability of II to penetrate the blood-brain barrier and to achieve effective concentration in the brain. II was found to inhibit the biosynthesis of prostaglandin. These findings along with the physicochemical properties suggest that although II does not fall structurally under any category of anti-inflammatory drugs the mechanism of action may be similar to that for non-steroidal acidic anti-inflammatory drugs.

Administration, Oral↗