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Biomedical subjects

K Takada

Publications and source records attributed to K Takada.

At least 703 records · Page 39Linked to original sources
PubMed1987

Capacitation-related changes in antigen distribution on mouse sperm heads and its relation to fertilization rate in vitro.

The anti-mouse sperm monoclonal antibody OBF13 did not react with fresh epididymal sperm. However, when sperm were incubated in a culture medium capable of inducing capacitation, the entire head of the sperm began to react with this antibody. This change of reactivity was not observed when sperm were incubated in a Ca2+-free medium. The change of the reactivity to the antibody was studied in relation to the fertilizing ability of sperm as measured in an in vitro fertilization system; a significant correlation was observed between the appearance of head-stained sperm and fertilization rate.

Acrosome↗
PubMed1987

Anesthetic management in the arterial switch "jatene" operation for transposition of the great arteries.

The arterial switch "Jatene" operation for transposition of the great arteries (TGA) is an anatomic reconstruction at the level of the great arteries with reimplantation of the coronary arteries. The anesthetic management of 46 patients who underwent the Jatene operation between 1982 and 1985 was retrospectively reviewed. The mean age was 12.3 +/- 11.2 months (youngest: 4 days) and the mean body weight was 7.0 +/- 2.8 kg (smallest: 3.0 kg). Anesthesia was induced with ketamine in 35 patients, and maintained with morphine in 36 patients. Catecholamine (CA) drugs were given to 10 patients before cardiopulmonary bypass (CPB) and to all patients after CPB. In addition, nitroglycerin (NTG) was given to 13 patients during and after CPB. Platelets were given to prevent bleeding due to platelet damage caused by CPB. Six patients died, producing a mortality rate of 13%. Body weight, age, anesthetic agent, dose of CA, volume of blood loss, and duration of aortic cross-clamping, anesthesia, and operation were not significantly related to the deaths. Urinary output was significantly smaller (P < .05) in the patients who died. The LV/RV pressure ratio was as low as 0.625 and 0.645 in two of six deaths due to left ventricular hypoplasia. Severe pulmonary hypertension occurred in the postoperative period in two patients, and two patients had heart failure following a previous operation for coarctation or interruption of the aorta. Since hypotension during induction is detrimental in these cases, ketamine was commonly used as an induction agent. Morphine was chosen rather than fentanyl to avoid bradycardia. Administration of CA drugs produced an inotropic effect on the heart, and NTG helped maintain coronary blood flow and prevented pulmonary hypertension. There were no anesthetic deaths as judged by both the surgeons and anesthesiologists.

Adjuvants, Anesthesia↗
PubMed1987

A Golgi study of the cerebral cortex in Fukuyama-type congenital muscular dystrophy, Walker-type "lissencephaly," and classical lissencephaly.

The cortical neuronal organization of the brain was studied and compared in three conditions. The neurons in the polymicrogyric cortex from a subject with Fukuyama-type congenital muscular dystrophy and from a child with ocular dysplasia (Walker-type lissencephaly) were large, irregularly aligned, and not completely mature. In the former condition, the abnormal neuronal arrangement was predominantly in the superficial cortex; in the latter both the superficial and deep cortex were involved. These two diseases may have a similar pathogenetic mechanism. In classical lissencephaly without evidence of other disease manifestations, the neurons were arranged in a radial pattern with heterotopia but no large neurons. The pathogenesis of these conditions is discussed.

Cerebral Cortex↗
PubMed1987

Effects of mucopolysaccharides on penicillin-induced lysis of Staphylococcus aureus.

Effects of four mucopolysaccharides and dextran sulphate on penicillin-induced lysis of Staphylococcus aureus FDA 209P were studied. Heparin and dextran sulphate inhibited lysis, whereas hyaluronic acid enhanced it. Chondroitin sulphates A and C had no effect. Incubation of S. aureus suspended in 0.03 M phosphate buffer (pH 7.0) with dextran sulphate inhibited autolysis of the bacteria, whereas incubation with hyaluronic acid enhanced autolysis. Both extracellular and cell-associated autolysin activities of S. aureus were suppressed by dextran sulphate and high concentrations of heparin. The addition of hyaluronic acid enhanced autolysin activity. The release of lipoteichoic acid (LTA), a modulator of autolysin activity, from penicillin-treated bacteria was inhibited by heparin and dextran sulphate. However, hyaluronic acid had no effect on release of LTA. These results suggest that inhibition of penicillin-induced lysis of S. aureus by heparin results mainly from inhibition of LTA release while dextran sulphate inhibits both autolysin activity and LTA release. Hyaluronic acid appears to enhance penicillin-induced lysis through activation of the autolysins.

Bacteriolysis↗
PubMed1987

Phenotypic and genotypic analysis of chronic myelogenous leukaemia with T lymphoblastic and megakaryoblastic mixed crisis.

A case of blast crisis in chronic myelogeneous leukaemia (CML) in which two distinct cell lineages were involved is presented. The phenotype of blasts in lymph nodes was T11 (CD2)+, Ia+, TdT+, suggesting T cell lineage. On the other hand, blasts in bone marrow and peripheral blood expressed platelet glycoprotein IIb/IIIa complex on their surface, suggesting megakaryocyte lineage. Cytogenetic analysis of lymph node and bone marrow cells revealed the abnormalities, inv(7) (p15q34) and t(1;3) (q23;q21), respectively, as well as the presence of the Ph1 chromosome in both cell types. Rearrangement of the T cell receptor beta-chain gene was detected in lymph node blasts, although blast cells in peripheral blood showed a germ line configuration. The involvement of T cell and megakaryocyte lineages in the blast crisis phase of CML was confirmed in our phenotypic and genotypic analysis, and the pathogenic association between blast crisis lineages and the additional chromosome abnormalities present is discussed.

Blast Crisis↗
PubMed1987

Both the rightward and the leftward open reading frames within the BamHI M DNA fragment of Epstein-Barr virus act as trans-activators of gene expression.

The BamHI M DNA fragment of Epstein-Barr virus was shown to activate transcription of the cotransfected chloramphenicol acetyltransferase gene under the control of the simian virus 40 early promoter. Both the BamHI-BglII and the HindIII-BamHI subfragments of the BamHI M fragment, corresponding to the rightward reading frame BMRF1 and the leftward reading frame BMLF1, respectively, had the ability to activate transcription from the simian virus 40 promoter. The trans-activating function was well correlated with the expression of nuclear early antigens, which suggests that early antigens encoded by BMRF1 and BMLF1 are responsible for trans-activation and possibly play a role in regulated expression of virus genomes.

Acetyltransferases↗
PubMed1987

Walker-Warburg syndrome with skeletal muscle involvement. A report of three patients.

Three patients with Walker-Warburg syndrome are reported. In all, severe hypotonia and ocular abnormalities were noted soon after birth, followed by a rapid increase of head size. Examination of the brain showed regions of complete agyria, cortical dysplasia of the cerebrum, cerebellar micropolygyria, marked hydrocephalus and aqueduct stenosis. In skeletal muscles, advanced myopathy consistent with dystrophic change was present. The cortical dysplasia in this syndrome is similar to the severest pattern of the cortical dysplasia seen in Fukuyama congenital muscular dystrophy, but ocular abnormalities are rare in the latter. These two syndromes may be genetically distinct, despite the presence of cortical dysplasia and myopathy in both.

Brain↗
PubMed1987

Studies on the promoting effect of lipid-surfactant mixed micelles (MM) on intestinal absorption of colloidal particles. Dependence on particle size and administration site.

The effect of oleic acid-HCO60 mixed micelles (MM) on the absorption of colloidal particles by the large intestine was investigated using the in situ closed loops of rats. Two species of colloidal particles with different sizes, colloidal inks (Platinum ink 2.4-10 nm, Rotring ink 100-800 nm) and colloidal gold particles (mean particle size 5, 20, 40 nm) were chosen. Macroscopic observation showed that in the case of Platinum ink the staining of the mucus of the whole large intestine was promoted by MM and the staining of the rectum remained even after removing the mucus layer. The regional lymph nodes and the thoracic lymph was also stained. On the other hand, in the case of Rotring ink, the stain in the large intestine after removing the mucus layer, in lymph nodes and in the thoracic duct lymph was not observed. The results of quantitative experiments using colloidal gold particles indicated: 1) the upper size limit of colloidal particles absorbed by the large intestine, under the influence of MM was approximately 40 nm, 2) colloidal gold particles were transported from the intestine selectively into the lymphatics and accumulated in the regional lymph nodes, 3) the absorption of colloidal gold particles was largely promoted by MM in the rectum area.

Animals↗
PubMed1987

Elastic recoil pressure arising from surface tension in hamster lungs treated with intratracheal bleomycin.

Lung elastic recoil pressure arising from surface tension (Ps) was evaluated in normal and bleomycin-treated lungs. Twenty two male golden hamsters were separated into a control group (group A, n = 10) and a bleomycin group (group B, n = 12). Group B was given a single intratracheal instillation of bleomycin and group A was given normal saline as a control. Thirty days after instillation, three cycles of static air -and saline-filled pressure-volume curves (P-V curve) were measured. Ps was graphically derived from air- and saline-filled P-V curves. The Ps of groups A and B were compared at the same lung volumes. Mean body weight and nose-to-tail length of the two groups did not differ significantly. Total lung capacity, defined as lung air volume at a transpulmonary pressure of 25 cmH2O, was significantly smaller in group B (mean +/- S.E. was 4.08 +/- 0.20 ml) than in group A (mean +/- S.E. was 5.23 +/- 0.12 ml) (p less than 0.01). The Ps of group B was significantly larger than that of group A at all lung volumes studied (p less than 0.01-0.05). These results indicate that the lung elastic recoil pressure component due to the surface tension was increased by intratracheal instillation of bleomycin in hamsters.

Animals↗
PubMed1987

Cigarette smoke modifies bleomycin-induced lung injury to produce lung emphysema.

The effect of cigarette smoke exposure on the development of bleomycin (BLM)-induced pulmonary fibrosis was studied. Hamsters 3 weeks of age were divided into four groups, control (C), BLM treated (B), cigarette smoke exposure (T), and cigarette smoke plus BLM (TB). Cigarette smoke exposure was started 5 days after the beginning of feeding in a desiccator which received a flow of smoke. A single intratracheal dose of 0.5 mg of BLM per 100 g body weight was administered 30 days after feeding. Sixty days after feeding the animals were killed for measurement of pressure-volume (P-V) relationships and microscopic observations. At 60 days the deflation P-V curves in B and TB were shifted significantly downward and to the right of that of C and T, respectively. P-V curves in TB were shifted significantly upward and to the left of that of B, almost returning to that of C. Light-microscopic examination showed no evidence of emphysema in the lung of T. In contrast, in the lung of TB there were destruction of the alveolar walls, varying degrees of enlargement of alveolar spaces and fibrous thickening of the alveolar septa. These results suggest that BLM-induced lung injury may be modified by cigarette smoke to produce lung emphysema.

Animals↗
PubMed1987

New tylosin analogs produced by mutants of Streptomyces fradiae.

2'''-Demethoxytylosin (component IIIc), 2'''-demethoxy-4'''-epi-tylosin (component IIId) and 2'''-O-demethyltylosin (component Vb) were produced by blocked mutant strains of Streptomyces fradiae. Fermentation, isolation, structure determination and biosynthetic considerations of these tylosin analogs are described.

Chemical Phenomena↗
PubMed1987

Influence of methoxamine, 5-hydroxytryptamine and physically induced low pH on thermal sensitivity and thermotolerance.

The influence of pH on split-dose hyperthermic response of non-resistant and thermotolerant Ehrlich tumors was studied. Vasoactive agents, methoxamine and 5-hydroxytryptamine (5-HT) and, mechanical interruption of the tumor blood flow by wire technique were applied in combination with hyperthermia at 72-hour intervals, where an increased thermal response was observed in Ehrlich tumor. A potential influence in suppressing the induction of thermotolerance (hyperthermia at 24-hour intervals) was evident in the case of 5-HT and methoxamine. These vasoactive agents and the wire technique showed a selective effect in reducing the tumor microcirculation as well as lowering its pH. However, unlike the wire technique, the pH was rather low in the postheating period in the case of 5-HT and methoxamine. Poor tumor vascularization induced by vasoactive agents or physical means would demonstrate a poor nutritional condition with a low pH, whereby an increase in thermal response would be obvious and may be expected to have maximal influence either in the decay or in delaying the induction of thermotolerance. A low tumor pH particularly during the postheating period may have some role against the development of thermotolerance.

Animals↗
PubMed1987

The effect of 3-methylcholanthrene on postlanosterol cholesterol biosynthetic pathways in mouse skin.

Repeated topical application of 3-methylcholanthrene to the backs of BALB/c mice lowered the tissue levels of lathosterol and provitamin D3, intermediates in one of the cholesterol biosynthetic pathways (the delta 7 pathway), though the activities of lathosterol 5-desaturase and provitamin D3 7-reductase were similar to those of control animals. These results seemed to indicate that carcinogen treatment exerted a depressive effect at some earlier step(s) than lathosterol synthesis. However, the content of cholesterol in mouse skin was not lowered in these animals, suggesting that another biosynthetic pathway might be activated. When diazacholesterol, which is known to inhibit the conversion of desmosterol to cholesterol, was administered together with the carcinogen, a marked accumulation of desmosterol was observed compared to animals given only diazacholesterol. Since desmosterol is an intermediate in the pathway in which the delta 24 double bond is reduced at the final step (the delta 24 pathway), this seemed to suggest that the delta 24 pathway was activated by carcinogen treatment.

Administration, Topical↗