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Biomedical subjects

A Masuda

Publications and source records attributed to A Masuda.

At least 343 records · Page 19Linked to original sources

[Clinical studies on cefoxitin in the prevention of postoperative infections and the treatment of postoperative pulmonary and urinary tract infections].

This clinical trial was designed to evaluate the efficacy, safety and patient tolerance of cefoxitin (CFS) in 46 patients who were admitted to the hospitals from June 1983 to April 1984. The daily doses of CFX for 34 patients (ages ranged from 6 to 75 years old) were 2 to 8 g to prevent the infections and for 12 patients (ages ranged from 55 to 81 years old) were 2 to 6 g to treat the infections by intravenous drip infusion 1 or 3 times a day in divided doses. The following results were obtained. All of 34 patients with intracranial operation who received CFX for prevention of postoperative infections showed good results. Of 12 patients with postoperative pneumonia, infections of urinary tract and late meningitis, 11 patients showed good results. One patient was discontinued on the 3 days because of the drug eruption which improved 3 days after. The side effect was noted in only 1 patient. This was eruption which improved 3 days after the stop of the administration. The influences to the laboratory data due to CFX were not recognized. The results of this study demonstrated that CFX was an excellent drug for the prevention and treatment of the postoperative infections in the neurosurgical field because of high efficacy rate and safety.

Adolescent↗

DNA cloning of Plasmodium falciparum circumsporozoite gene: amino acid sequence of repetitive epitope.

A clone of complementary DNA encoding the circumsporozoite (CS) protein of the human malaria parasite Plasmodium falciparum has been isolated by screening an Escherichia coli complementary DNA library with a monoclonal antibody to the CS protein. The DNA sequence of the complementary DNA insert encodes a four-amino acid sequence: proline-asparagine-alanine-asparagine, tandemly repeated 23 times. The CS beta-lactamase fusion protein specifically binds monoclonal antibodies to the CS protein and inhibits the binding of these antibodies to native Plasmodium falciparum CS protein. These findings provide a basis for the development of a vaccine against Plasmodium falciparum malaria.

Amino Acid Sequence↗

Chinese hamster cell mutants with defective endocytosis of low-density lipoprotein contain altered fatty acid composition in the membrane.

Chinese hamster V79 cell mutants resistant to compactin (ML236B), a specific inhibitor of 3-hydroxy-3-methylglutaryl coenzyme A reductase, are defective in endocytosis of low-density lipoprotein (1). Two resistant clones, MF-2 and MF-3, differ in lipid composition from the parental V79 strain. In both the total cells and membrane fraction, the ratio of palmitoleic acid (16:1)/palmitic acid (16:0) is 0.4-0.5 in MF-2 and 1.7-1.8 in MF-3 while that in V79 is 0.2-0.3. By contrast, a hybrid clone between V79 and MF-3 shows a ratio of palmitoleic acid to palmitic acid very similar to that of V79. The synthesis of palmitoleic acid from acetate in the resistant clone is higher than in V79.

Acetates↗

Cytological characteristics of cultured epithelial cells from thymomas in BUF/Mna rats.

Epithelial cells (ECs) from spontaneously developed thymomas in BUF/Mna rats were cultured, characterized and compared with ECs from normal thymuses. The ECs from thymomas had many more keratin filaments and PAS-positive vesicles in the cytoplasm than ECs from normal thymuses. The size and shape of ECs and their nuclei were heterogeneous and about 20% of ECs from thymomas had more than one nucleus. However, the growth rates and saturation densities of ECs from thymomas in monolayer culture were not markedly different from those of normal thymuses. The ECs from thymomas cultured in soft agar did not form any colonies. The distribution of the numbers of chromosomes found in ECs from thymomas was slightly broader than that in normal ECs, but no specific abnormalities nor marker chromosomes were noted. These findings indicate that ECs from thymomas are abnormal, but suggest that they are not malignant in nature.

Animals↗

Beating activity of heterokaryons between myocardial and non-myocardial cells in culture.

Cultured mouse myocardial cells grown as monolayers fused upon treatment with HVJ (Sendai virus). The myocardial cells also fused with quail myocardial cells, neuroblastoma cells and non-excitable cells, such as KB cells. The beating activity of these heterokaryons was studied in the present work. Heterokaryons composed of myocardial cells from different species maintained spontaneous beating activity for 2 days or more. Those of one myocardial and one neuroblastoma cell maintained the activity for 22-26 h, while those of one myocardial and one non-excitable cell, such as KB cell, lost the activity within 2-4 h after addition of HVJ. Heterokaryons that had stopped spontaneous beating did not contract on application of electrical-field stimulation. The ration of non-myocardial cells in the heterokaryons increased in inverse proportion to the decrease in beating activity of the heterokaryons. Study of the rapid disappearance of beating activity in heterokaryons composed of one myocardial and one KB cell showed that both excitability of the cell membrane and myofibril organization were rapidly lost.

Animals↗

Enhancement of N-bis(2-hydroxypropyl)nitrosamine-initiated lung tumor development in rats by bleomycin and N-methyl-N-nitrosourethane.

Potential modification of N-bis(2-hydroxypropyl)nitrosamine (DHPN)-induced lung carcinogenesis by bleomycin and N-methyl-N-nitrosourethane (MNUT) was investigated in male F344 rats. Rats were given 0.2% DHPN for 1 week followed by a weekly i.p. injection of either bleomycin at 2.0 mg/kg body wt or of MNUT at a dose of 1.0 mg/kg body wt for 35 weeks. Animals given DHPN followed by solvent administration alone, either saline or 0.02% ethanol and animals given bleomycin or MNUT without DHPN pretreatment were served as controls. Bleomycin treatment increased the incidence of cancer, whereas hyperplasia, adenoma and cancer of the lung were all significantly elevated after MNUT administration. MNUT alone induced low incidences of lung tumors. Bleomycin also increased the incidence of papillary or nodular hyperplasia of the urinary bladder while it inhibited the development of thyroid tumors. MNUT, however, did not affect tumor development in other organs.

Adenocarcinoma↗

Insulin-induced formation of ruffling membranes of KB cells and its correlation with enhancement of amino acid transport.

Insulin induced the formation of ruffling membranes in cultured KB cells (a cell strain derived from human epidermoid carcinoma) within 1-2 min after its addition. The ruffled regions were stained strongly with antibody to actin but not that to tubulin. Pretreatment of KB cells with agents disrupting microfilaments (cytochalasins), but not with those disrupting microtubules (colcemid, nocodazole, and colchicine) completely inhibited the formation of ruffling membranes. Pretreatment of KB cells with dibutyryl cyclic AMP, but not with dibutyryl cyclic GMP, also inhibited the formation of ruffling membranes. Addition of insulin enhanced Na+-dependent uptake of a system A amino acid (alpha-amino isobutyric acid; AIB) by the cells within 5 min after the addition, and decreased the cyclic AMP content of the cells. Treatments that inhibited insulin-induced formation of ruffling membranes of KB cells also inhibited insulin-induced enhancement of their AIB uptake. From these observations, the mechanism of insulin-induced formation of ruffling membranes and its close correlation with AIB transport are discussed.

Actins↗

In vitro study on contribution of oxidative metabolism of isolated rabbit heart mitochondria to myocardial reperfusion injury.

The present study was performed to clarify oxygen-induced damage following myocardial reperfusion, using three mitochondrial preparations from isolated rabbit hearts (nonischemic hearts and those subjected to 40 and 90 minutes of normothermic global ischemia). The viability of mitochondria was evaluated by adenosine triphosphate generation. The extent of mitochondrial injury produced by reactive oxygen metabolism was assessed by the intensity of hydroxyl radical signal detected with electron spin resonance spectroscopy and the reduction of coenzyme Q10 level. The greatest oxygen-induced injury was observed in 40-minute ischemic mitochondria exposed to pure oxygen. The use of superoxide dismutase and catalase satisfactorily prevented the oxygen-induced injury. Moreover, the net adenosine triphosphate generation of the 40-minute ischemic mitochondria was comparable to that of the nonischemic mitochondria without the enzymes. These results suggest that reperfusion of the ischemic myocardium with viable mitochondria is deleterious, because mitochondria are susceptible to injury resulting from oxidative metabolism, and that the use of superoxide dismutase, together with catalase, is beneficial for the restoration of cardiac function after ischemia.

Adenosine Triphosphate↗

Age-related changes in plasma growth hormone response to growth hormone-releasing factor in man.

The response of plasma growth hormone to synthetic growth hormone-releasing factor (hpGRF-44) administered intravenously was examined in normal men of various ages ranging from 20 to 75 years. Most of the subjects who were over forty years old had either no or much lower response of plasma growth hormone to hpGRF-44. In contrast plasma growth hormone increased markedly after hpGRF-44 injection in all men in their twenties and thirties. The mean peak level of plasma GH following hpGRF-44 administration was 29.6 +/- 20.4 (SD) ng/ml in men in their twenties, 30.2 +/- 26.5 ng/ml in their thirties, 9.7 +/- 5.2 ng/ml in their forties, 10.9 +/- 5.4 ng/ml in their fifties, 8.4 +/- 4.8 ng/ml in their sixties and 8.1 +/- 7.5 ng/ml in their seventies. These results suggest that somatotroph cells become less sensitive to growth hormone-releasing factor with aging.

Adult↗