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Biomedical subjects

Y Shimada

Publications and source records attributed to Y Shimada.

At least 739 records · Page 41Linked to original sources

Application of HPLC measurement of plasma concentration of gabexate mesilate.

The plasma concentration of gabexate mesilate (ethyl-p-(6-guanidinohexanoyloxy) benzoate) methanesulfonate (GM), FOY, was measured on a high performance liquid chromatography. GM concentrations ranging from 1 to 50 micrograms/ml of whole blood were able to be determined with this method. The half-life of GM in plasma was 55 seconds and the minimum concentration of GM which affected the activated coagulation time of whole blood (ACT) was 10 micrograms/ml. This method is sensitive and accurate to provide us with the pharmacodynamic basis for the determination of the effective plasma concentration of GM with respect to its anticoagulant activity.

Anticoagulants↗

The acetylcholine receptors of human muscles are not stained with rhodamine-labeled erabutoxin-b.

The skeletal muscles from man and other vertebrates were incubated in rhodamine-labeled erabutoxin-b(TMR-Eb), and the distribution of the acetylcholine receptors (AChRs) at the neuromuscular junctions was examined under a fluorescence microscope. The AChRs of human muscles were not stained with TMR-Eb, whereas those of fish, frog, chicken, mouse, rat, cat and monkey muscles were stained under the same conditions. It was concluded that human AChRs have low or no binding ability for TMR-Eb.

Erabutoxins↗

Myofibrillogenesis in vitro as seen with the scanning electron microscope.

The present study describes an experimental approach whereby myofibrillogenesis and the three-dimensional arrangement of myofibrils present within cultured skeletal muscle cells can be examined using the scanning electron microscope. This procedure uses cells that have been cultured on gold-coated coverslips, and treated with Triton X-100 to extract the cell membrane and the soluble cytoplasm. Subsequent electroconductive staining by treatment with thiocarbohydrazide and osmium allows the myofibrils to be visualized. The images of myofibrils in various states of development observed by this method generally accords to those previously reported by transmission electron microscopy. Cell elongation and adhesion to the substrate causes mechanical stress from different directions which meet at branchings of the cultured myotubes. Many myofibrils are observed to run in the direction of the inferred stress lines.

Animals↗

Differences in urinary monochlorobenzene metabolites between rats and humans.

The high performance liquid chromatographic method for the determination of p-chlorobenzene mercapturic acid and 4-chlorocatechol conjugates is described. For determination of urinary mercapturic acid, the benzene extract from urine was injected into a liquid chromatograph and for determination of urinary 4-chlorocatechol conjugates, hydrolysate was dissolved in methanol. The methanol solution containing 4-chlorocatechol was injected into a liquid chromatograph. Differences in urinary excretion of monochlorobenzene between rats and humans were studied. Monochlorobenzene was administered to rats intraperitoneally, and to humans orally or by inhalation. Urinary p-chlorophenylmercapturic acid, and 4-chlorocatechol after hydrolysis of its conjugate, were measured. The amount of total metabolites is proportional to the doses administered to rats, rabbits and mice by intraperitoneal injection. The ratio of urinary mercapturic acid to 4-chlorocatechol is in the order of rats, mice and rabbits by intraperitoneal injection, and rats and human beings by oral administration. The excretion of p-chlorophenylmercapturic acid was markedly less than that of 4-chlorocatechol in humans who received monochlorobenzene orally or by inhalation. The results indicate that the 4-chlorocatechol conjugate is a suitable index of metabolites in the urine of workers exposed to monochlorobenzene.

Acetylcysteine↗

Neuronal cell-surface specific antigen(s) is expressed during the terminal mitosis of cells destined to become neuroblasts.

By immunizing mice with cells from embryonic chick motoneuron cultures, an antiserum was produced which recognizes an antigen(s) restricted to cell surfaces of most, or all, neurons. With the use of this antiserum, the appearance of neuron-specific antigenicity in cells of the embryonic spinal cord was examined by indirect immunofluorescence microscopy. The antigen or set of antigens reacting with this antiserum was first detectable in the neural tube of chick embryos at stage 15-16 (V. Hamburger and H.L. Hamilton, 1951, J. Morphol. 88, 49-92). In addition to the neuroblasts located in the mantle layer, some mitotic cells as well as some spindle-shaped cells in the germinal layer were antigen positive. Immunofluorescence microscopy combined with autoradiography revealed that none of the antigen-positive cells could be labeled with [3H]thymidine; thus they do not synthesize DNA, and none of the cells in the DNA synthetic phase expressed the antigen(s). As the neuroblasts do not synthesize DNA after they have differentiated from the germinal cells, we believe that the antigen-positive cells are differentiated elements and that the differentiation of membranes specific for neurons begins already before or during the terminal mitosis of cells which will be defined as neuroblasts.

Animals↗

Isoform variants of troponin in skeletal and cardiac muscle cells cultured with and without nerves.

Immunofluorescence microscopy shows that cultured skeletal and cardiac muscle cells of chicken embryos exhibit the same stainabilities with antibodies against skeletal and cardiac troponin components as do those in embryos. Muscle cells of each type cultured with motor or sympathetic nerves or in medium containing the nerve extract exhibit the same reactivities as do those in adult animals. Cardiac muscle cells incubated in the nerve-conditioned medium also change the form of troponin components to the adult type. It appears that the differentiation of individual muscle fibers to specific types is induced by nerves, and especially by the neurohumoral effect.

Animals↗

Increase in the activity of Rhizopus delemar lipase on water-soluble esters by its binding with phosphatidylcholine.

Rhizopus (Rh.) delemar (ATCC 34612) C-lipase was found to exhibit a slight activity towards water-soluble esters. The hydrolytic reaction of this lipase on alpha-naphthyl acetate was competitively inhibited by the presence of olive oil or Tween 80. This finding showed that both substrates, insoluble triglyceride and water-soluble ester, were hydrolyzed at the same site on the enzyme. The activities on water-soluble esters (alpha-naphthyl acetate, beta-naphthyl acetate, methyl acetylsalicylate and Tween 80) increased on binding of lipase with phosphatidylcholine (PC), although the activity on olive oil did not change. The increase in activity on water-soluble esters was due to the increase in the Vmax for its hydrolysis. It appears that local structural change of the catalytic site on lipase occurred on binding of PC to the lipase molecule and resulted in an increase in the activity on water-soluble esters. The temperature dependence of the hydrolysis of water-soluble esters demonstrated that the activation energy was lowered on binding of PC to the lipase molecule, and this resulted in an increase in the activity.

Binding Sites↗

Gabexate mesilate (FOY) therapy of disseminated intravascular coagulation due to sepsis.

Gabexate mesilate (FOY), a synthetic serine proteinase inhibitor, has an anticoagulant activity in the absence of antithrombin-III. We investigated FOY therapy for the treatment of disseminated intravascular coagulation (DIC) associated with sepsis in 15 patients (group F), and compared it with heparin therapy in 8 patients (group H). Successful treatment was observed in 13 patients in group F and in 4 patients in group H. The efficacy of the therapy in both groups was not significantly different. However, in patients whose antithrombin-III values were less than 20 mg/dl at the initiation of the therapy, FOY therapy was successful in 6 of 7 patients, whereas heparin therapy was not at all successful in 4 patients (rho less than 0.05). We conclude that FOY can be used as effectively as heparin for the treatment of DIC, and that FOY therapy is superior to heparin therapy in DIC associated with decreased antithrombin-III.

Adult↗

Amino acids and thiobarbituric acid reactive substances in cerebrospinal fluid and plasma of patients with septic encephalopathy.

Amino acids and thiobarbituric acid reactive substances (TBARs) in the cerebrospinal fluid (CSF) and plasma were identified and assayed in 5 patients with septic encephalopathy. Levels of all the high molecular weight neutral amino acids (LNAAs) appeared to increase in the CSF. CSF levels of phenylalanine (PHE) and methionine (MET) increased significantly by factors of 20.9 and 9.5, respectively, and the plasma PHE level increased 7.5-fold. No significant changes in branched-chain amino acids were observed in either the CSF or plasma. The CSF/plasma ratios of valine (VAL), tyrosine (TYR), PHE, and MET significantly increased to 0.21, 0.46, 0.52, and 0.52, respectively. TBAR levels increased 4-fold in the CSF and also were slightly increased in the plasma, suggesting that lipid peroxidation in the central nervous tissues is markedly increased. We conclude that increases in LNAA levels and in lipid peroxidation in the central nervous tissues may play important roles in the development of septic encephalopathy.

Aged↗

Postural hypotension and low R-R interval variability in parkinsonism, spino-cerebellar degeneration, and Shy-Drager syndrome.

Systolic blood pressure, mean R-R interval, and R-R interval variance were studied in patients with Parkinson's disease, spinocerebellar degeneration, and Shy-Drager syndrome. Postural hypotension correlated with anhidrosis (p less than 0.05), indicating sympathetic vasomotor dysfunction. Reduction of R-R interval variance while resting supine correlated with bladder-bowel dysfunction (p less than 0.05), indicating parasympathetic impairment. Reduction of R-R interval variance after postural changes correlated with constipation (p less than 0.005), postural hypotension (p less than 0.05), and anhidrosis (p less than 0.05), indicating both parasympathetic and sympathetic involvement. Dynamic study of the R-R interval provides objective information about autonomic function in neurologic disease.

Adult↗

Safracins, new antitumor antibiotics. III. Biological activity.

Safracins A and B have antibacterial activity against Gram-positive and Gram-negative bacteria in vitro but no therapeutic activity in mice infected with Staphylococcus aureus. Safracins A and B induce abnormal morphological changes in Echerichia coli cells. Tests with transplantable mice tumors demonstrate that safracins A and B inhibit the growth of P388 leukemia and IMC carcinoma.

Animals↗