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Biomedical subjects

M Oka

Publications and source records attributed to M Oka.

At least 613 records · Page 34Linked to original sources
PubMed1987

In situ microfluorometry of kinetoplast and nuclear DNAs in Trypanosoma gambiense. Unusual repairment of DNA after treatment with bleomycin.

The blood stream form of Trypanosoma gambiense was smeared on a nonfluorescent slide glass with 1 microgram/ml of Hoechst 33258 in 1 mM Tris-HCl buffer (pH 7.2) containing 1% 2-mercaptoethanol and subjected to the in situ microfluorometry. Effects of bleomycin (BL) on the kinetoplast (K)-DNA and nuclear (N)-DNA of T. gambiense were examined in the time course to 6 h after injection of BL into the infected mice. An enhancement of fluorescence occurred 30 min after the injection and then slowed down. This enhancement was due to DNA synthesis both in the K-DNA and N-DNA. This suggests that the strong repairment occurs in both DNAs after treatment with BL.

Animals↗
PubMed1987

Hemodynamic changes during dental extraction and post-extraction bleeding in patients with prosthetic heart valves.

Hemodynamic changes during dental extraction and postextraction bleeding were retrospectively evaluated in patients with prosthetic heart valves. It was found that the rate pressure product had a higher value in the period of anesthesia and during dental extraction. There was a tendency for a high RPP difference corresponding to an increased incidence of ECG changes, such as ST-T, QRS, P, and tachycardia. ECG changes were frequently observed high in procedures which required high doses of local anesthetic at one time or when multiple dental extractions were undertaken, whereas they seemed to have no positive relation to the number of heart valves replaced. Approximately 87% of the extractions were carried out under continuous anticoagulant therapy with a pretreatment coagulability level, of which 32% had bleeding during the first 24 h.

Adult↗
PubMed1987

Polyclonal B-cell-activating factors produced by spleen cells of mice stimulated with a cell homogenate of Trypanosoma gambiense.

The effect of injection of a cell homogenate of Trypanosoma gambiense into mice on the production of soluble factors responsible for the induction of polyclonal B-cell activation (PBA) by their spleen cells was examined. PBA was induced by injection of the cell homogenate and was also detected in mice treated with either the serum or the spleen cells of mice treated with the cell homogenate. PBA-inducing activity became detectable in the serum and spleen cells as early as 12 h after injection of the cell homogenate, reached a peak on day 2, and then decreased. This activity was also detected in the culture medium of spleen cells obtained 2 days after injection of the cell homogenate. For determination of the type of spleen cells producing the PBA-inducing factor, the day 2 spleen cells were fractionated on the basis of differences in their adhesive properties. Spleen cells in the effluents from a Sephadex G-10 column (T and B cells) and a nylon wool column (T cells) and those adhering to a plastic flask (macrophages) all produced the PBA-inducing factor. The production of PBA-inducing factor by whole spleen cells and by cells adherent to the plastic flask was not affected by treatment with anti-Thy-1.2 antibody and complement. These data suggest that soluble factors derived from macrophages and T cells could contribute to the induction of PBA. The PBA-inducing activity in the conditioned medium was completely inactivated by treatment at pH 2.0, heating at 56 degrees C for 30 min, or exposure to 0.1% sodium dodecyl sulfate. The results are discussed in relation to cytokines that could affect B-cell activation.

Animals↗
PubMed1987

Palindromic rheumatism. A clinical survey of sixty patients.

Sixty patients with palindromic rheumatism (PR) with a total follow-up time of 598 years and 295 years prospectively are presented. The study shows that PR is not a rare condition, but the syndrome is often ignored or misdiagnosed by the physician. Most cases of PR appear to evolve into chronic arthritis. PR may precede other kinds of systemic diseases, such as SLE, Wegener's granulomatosis, and multiple myeloma. The presence of PR in patients with fibromyalgia is reported in this paper. Gold appears to be the best drug for the treatment of PR. Cases of fibromyalgia and PR are treated successfully with antimalarial drugs. Our proposed diagnostic criteria for PR are as follows: 1) recurrent attacks of sudden-onset mono or polyarthritis or of periarticular tissue inflammation, lasting from a few hours to one week; 2) verification of at least one attack by a physician; 3) subsequent attacks in at least three different joints; 4) exclusion of other forms of arthritides.

Adult↗
PubMed1987

Scintigraphy of rheumatoid peripheral joints. Reliability of visual assessment vs. computerized methods.

99mTc-methylene diphosphonate (99mTc-MDP) scintigraphy of peripheral joints was studied by visual evaluation (Visual Assessment) of the scintigrams and by a computerized region-of-interest (ROI) method without, or with a reference region (ROI method or Corrected ROI method). Sixteen rheumatoid patients and a total of 477 peripheral joints were studied and the results compared with clinical joint activity evaluated by joint palpation. The ROI method without a reference proved to be insensitive and hence unsuitable for clinical use. The results of Visual Assessment and the Corrected ROI method correlated well with each other and with clinical joint activity. The sensitivity of the methods in detecting a clinically inflamed finger joint was: ROI 6%, Corrected ROI 71% and Visual Assessment 75%. The corresponding figures for peripheral joints of the feet were as follows: 28%, 41% and 58%. We conclude that, for clinical use, Visual Assessment of the scintigram is adequate and the method of choice.

Adult↗
PubMed1987

General pharmacology of the novel antiepileptic compound zonisamide. 1st communication: effects on central nervous system.

The effects of 1,2-benzisoxazole-3-methanesulfonamide (zonisamide, AD-810, CI-912), an antiepileptic compound, on the central nervous system were compared with those of carbamazepine and acetazolamide in experimental animals. 1. Zonisamide at an oral dose of 100 mg/kg was without effect on general behavior in mice except lowerings of pelvic, tail and body positions and ptosis. In rats, zonisamide slightly decreased the body temperature at the same dose. 2. Zonisamide (50 mg/kg p.o.) did not affect spontaneous alteration behavior and active avoidance performance in mice, although it impaired the acquisition of step-down passive avoidance behavior in mice. Carbamazepine (50 mg/kg) deteriorated the spontaneous alternation behavior. 3. Zonisamide (40 mg/kg i.v.) did not affect the relative power of cortical EEGs in gallamine-immobilized cats. Caudate spindles and recruiting responses, induced by electrical stimulation of the head of the caudate nucleus and the ventralis anterior thalamus, respectively, were not affected with the same dose of zonisamide in cats. On the other hand, carbamazepine (5 mg/kg) decreased the beta 2 relative power in the cortex, and enhanced both caudate spindles and recruiting responses. 4. Zonisamide (10 mg/kg i.v.) and carbamazepine (3 mg/kg) showed a tendency to depress the flexor reflex without affecting the neuromuscular transmission in anesthetized cats. 5. The central effects of zonisamide clearly differed from those of acetazolamide. Namely, acetazolamide markedly decreased brain pH at 25 mg/kg i.v., and increased regional cerebral blood flow at 100 mg/kg p.o. in rats. Zonisamide at 50 mg/kg i.v. and 100 mg/kg p.o. did not affect brain pH and regional cerebral blood flow, respectively. In addition, zonisamide (100 mg/kg p.o.) decreased brain contents of dopamine metabolite, DOPAC, with slight increase of a serotonin metabolite, 5-HIAA, in mice, and decreased brain contents of dopamine metabolites, DOPAC and HVA, in rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1986

Stimulation by vasoactive intestinal polypeptide of muscarinic receptor-mediated catecholamine secretion from isolated guinea pig adrenal medullary cells.

The effects of vasoactive intestinal polypeptide (VIP) on catecholamine (CA) secretion by isolated guinea pig adrenal medullary cells were studied. VIP (1 microM) alone induced only a slight secretion of CA, but it stimulated ACh-induced CA secretion. At concentrations of 0.01-1 microM, it stimulated muscarine-induced CA secretion, but not nicotine-induced CA secretion. It did not affect high K+ or Ca2+ ionophore-induced CA secretion. The stimulatory effect of VIP on muscarine-induced CA secretion was observed at muscarine concentrations of 2 200 microM and was detectable after 2 min incubation.

Adrenal Medulla↗
PubMed1986

Effect of age on the formation of cyclic nucleotides in guinea-pig tracheal smooth muscle in response to pharmacological agents.

The effects of isoproterenol, carbachol and other drugs on the cyclic AMP and cyclic GMP levels in tracheal smooth muscles of guinea-pigs of four different ages were investigated. Isoproterenol increased the cyclic AMP level several-fold in tracheal muscles from newborn (1 week) and young (4-7 weeks) guinea-pigs, but it caused less increase in the level in muscles from middle-aged (12 weeks) and old (20-24 weeks) guinea-pigs, although the basal cyclic AMP level at these ages was not significantly lower. The effects of prostaglandin E1 and cholera toxin in increasing the cyclic AMP level were also markedly less in muscle preparations from old guinea-pigs than in those from young ones. The increase in cyclic AMP levels caused by forskolin, an activator of adenylate cyclase did not decrease with age. Carbachol caused a 3- to 4-fold increase in the cyclic GMP level in muscle preparations from newborn and young guinea-pigs and more increase in the cyclic GMP level in preparations from middle-aged and old guinea-pigs. The increases in cyclic GMP level induced by high K+, histamine and sodium nitroprusside also increased with the age of the animals. These results suggest that the changes in the formation of cyclic AMP and cyclic GMP induced by various agents are due to changes at the post-receptor level.

Aging↗