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Biomedical subjects

T Matsuda

Publications and source records attributed to T Matsuda.

At least 1,459 records · Page 81Linked to original sources
PubMed1985

Involvement of sulfhydryl groups in the inhibition of brain (Na+ + K+)-ATPase by pyrithiamin.

Brain (Na+ + K+)-ATPase was protected by low concentrations of GSH from the inhibitory effect of pyrithiamin. The possible involvement of sulfhydryl groups in the inhibition was then studied by comparing the effect of pyrithiamin with that of N-ethylmaleimide on the enzyme. The treatment of rat brain (Na+ + K+)-ATPase with thesee inhibitors caused a significant decrease in reactivity of the enzyme to N-ethyl[3H]maleimide. N-Ethylmaleimide, like pyrithiamin, inhibited the partial reactions of (Na+ + K+)-ATPase system in parallel with the inhibition of the overall reaction. An SDS-polyacrylamide gel electrophoresis procedure indicated that pyrithiamin and N-ethylmaleimide inhibited Na+-dependent phosphorylation of the alpha(+) form of rat brain (Na+ + K+)-ATPase more than that of alpha, though the selectivity for the alpha(+) seemed to be higher with the former inhibitor than in the latter. The treatment also decreased sensitivity of the enzyme to ouabain inhibition. However, pyrithiamin- and N-ethylmaleimide-induced inactivations of the enzyme differed in the efficacy of GSH for protection and in the effect of the kind of ligands present during the reaction. Furthermore, pyrithiamin did not appear to interact directly with sulfhydryl groups, but caused the formation of disulfide in bovine brain (Na+ + K+)-ATPase. In contrast to N-ethylmaleimide, pyrithiamin did not affect the sulfhydryl-enzymes such as alcohol dehydrogenase and L-alanine dehydrogenase. It is concluded that pyrithiamin modifies the functional sulfhydryl groups of brain (Na+ + K+)-ATPase in a way different from N-ethylmaleimide and causes a structural change and inactivation of the enzyme.

Animals↗
PubMed1985

Species difference in temperature dependence of cardiac (Na+ + K+)-ATPase activity.

Cardiac (Na+ + K+)-ATPase from several species of animals were comparatively studied with respect to their molecular form and temperature dependence. The molecular weight of the catalytic subunit varied a little among species, but the difference did not correlate with the sensitivity of the enzyme to ouabain inhibition. Analysis of Arrhenius plots of the activities of the enzymes showed that enzymes showing break points of 24-25 degrees were relatively insensitive to ouabain inhibition whereas those enzymes with break points of 29-31 degrees were much more sensitive to the glycoside. This suggests that there is a difference in the interaction of cardiac (Na+ + K+)-ATPase with lipids between the ouabain-sensitive and -insensitive animals.

Animals↗
PubMed1985

Human IgE antibody to the carbohydrate-containing third domain of chicken ovomucoid.

Two kinds of the third domain, either with or without a carbohydrate chain, were prepared from chicken ovomucoid. The immunoreactivity of the domain preparations to human IgE antibody directed against ovomucoid was examined by using the sera from patients of egg allergy. About 30% of the serum antibody to ovomucoid reacted with the carbohydrate-containing domain, whereas little or no antibody with reactivity to the carbohydrate-free domain was detected, suggesting that the carbohydrate chain attached to the third domain played an important role in antigenic determinants of the carbohydrate-containing third domain against the human IgE antibody.

Animals↗
PubMed1985

Location of the inter-chain disulfide bonds of the third component of human complement.

Location of the disulfide bonds connecting three polypeptide chains (alpha 3, 27kd; 2, 43kd; beta, 75kd) of C3c has been investigated by partial reduction with cysteine followed by alkylation with 14C-monoiodoacetic acid. Treatment of C3c with cysteine produced a partially reduced fragment, composed of disulfide-linked beta and alpha 3 chains. A single thiol residue was detected on the alpha 3 chain but not on the beta chain of the fragment, suggesting that the alpha 2 chain in C3c is linked through a single disulfide bond to the alpha 3 chain but not to the beta chain.

Complement C3↗
PubMed1985

The presence of lymphatic stomata in the ovarian bursa of the golden hamster.

The histology and function of the lymphatic system in the ovarian bursa of the golden hamster were examined at each day of the estrous cycle. The lymphatic passage from the ovarian bursa to a para-aortic lymph node was stained black by india ink injected into the bursal cavity. This suggests that bursal fluid drains from the cavity via lymphatic vessels. Lymphatic stomata connecting the bursal cavity with the lymphatic lumen were consistently present throughout the cycle. However, the stomata were more frequently observed in the bursae on day 1 than on day 4 of the cycle. Also, they were more frequently observed in the bursa injected with 5 microliters of chick erythrocytes than in the contralateral (not injected) bursa in hamsters on day 4 of the cycle. These results suggest that the stomata are openings the patency of which varies in response to changes in the bursal cavity. There were regions where the lymphatic lumen was separated from the bursal cavity only by lymphatic endothelial cells. These regions were present throughout the estrous cycle. They may be patent stomata; dehiscence of junctions between the endothelial cells may give rise to stomata or widen the stomata orifices that are already present.

Animals↗
PubMed1985

Mechanical stability of elastomeric polymers for blood pump applications.

As a series of studies on the mechanical properties of materials used in cardiac prostheses, static and dynamic characteristics and stability of five kinds of elastomeric polymers have been studied by uniaxial tensile and fatigue tests in air at room temperature and in saline solution at 37 degrees C. Of all materials tested in this study, Texin MD85A, a segmented polyether polyurethane, has the lowest flexibility under static and dynamic conditions, with relatively high strength. Hexsyn, a polyolefin rubber, is highly flexible with little stress relaxation. However, this material has very low tensile strength and short elongation, and shows unstable change in the elastic modulus during cyclic deformation. Avcothane 51, a copolymer of polyurethane and silicon, has unstable mechanical properties and gradually stiffens upon cyclic deformation. On the other hand, Biomer, a segmented polyether polyurethane, has high flexibility and shows the most stable behavior during cyclic deformation regardless of test environment. Toyobo TM5, a similar segmented polyurethane to Biomer, has higher strength and ductility than Biomer, although its static and dynamic flexibility are slightly worse and less stable than those of Biomer. These results indicate that Biomer and Toyobo TM5 are more suitable for flexible components of cardiac prostheses.

Air↗
PubMed1985

Dystrophic axons in the nucleus gracilis of the normal rat containing cholecystokinin-like immunoreactivity. Light- and electron-microscopic observations.

Cholecystokinin immunoreactive (CCKI) axons in the nucleus gracilis of the normal rat were studied by light and electron microscopy using the peroxidase-antiperoxidase (PAP) immunocytochemical method. Immunoreactivity was found in both normal and dystrophic axons at various ages. Slightly enlarged CCKI varicosities were first observed in 2-month-old rats, gradually increased in number (max. at 21 months) and in diameter (up to 20 micron at 21 months), and then decreased (at 27 and 36 months). Dilatated CCKI fibers continuous with dystrophic varicosities also tended to increase proportionally in diameter. The dystrophic CCKI axonal profiles, first identified at the light-microscopic level and then observed under electron microscopy, had consistently characteristic features. In addition, numerous dystrophic nonreactive axonal profiles had morphological features differing from those of dystrophic reactive ones at advanced ages. These findings suggest that CCK may be partly involved in the formation of dystrophic axons in the nucleus gracilis.

Aging↗
PubMed1985

Synthesis of thiamine triphosphate in rat brain in vivo.

Thiamine metabolism in vivo was studied by intracerebroventricular injection of labeled thiamine in rat brain. Labeled thiamine was found to be rapidly converted to the phosphorylated thiamine esters. The distribution of the radioactive thiamine compounds was reached to steady state at 3 hr after injection: thiamine, thiamine monophosphate, thiamine pyrophosphate, and thiamine triphosphate were 8-12%, 12-14%, 72-74%, and 2-3%, respectively, in cerebral cortex. The presence of labeled thiamine triphosphate in the brain was further confirmed by the treatment with thiamine triphosphatase which had an absolute substrate specificity for thiamine triphosphate. These results suggest that thiamine triphosphate is synthesized in vivo in rat brain.

Animals↗
PubMed1985

Hexose and hexosamine concentrations in human pancreatic juice.

Hexose and hexosamine contents were measured in 117 samples of either duodenal or pancreatic juice from 49 subjects. The specimens were obtained by three methods: firstly, through a Dreiling's double lumen tube and with a pancreozymin secretin test performed simultaneously; secondly, by fiber duodenoscopy after an intravenous injection of secretin; thirdly, through a postoperative cannula without stimulation. The hexose content measured by phenol-sulfuric acid reaction correlated well with the hexosamine content measured by the Elson-Morgan method (r = 0.63, p less than 0.005). Since determination of hexose is not as complicated as that of hexosamine, the measurement of hexose content in the pancreatic juice seems to be more useful than measuring hexosamine for obtaining valuable information on pancreatic abnormalities.

Cholecystokinin↗
PubMed1985

Effects of implantation on the mechanical properties of the polyurethane diaphragm of left ventricular assist devices.

Tensile properties of blood pump diaphragms made from a segmented polyether polyurethane (Toyobo TM5) were studied after implanting in goats for variable periods of time up to 72 days. The implantation decreased the tensile strength and ultimate elongation at break, while the elastic modulus increased very slightly. These changes in the strength and ductility were primarily caused by the contact of material with blood rather than by the mechanical fatigue of material. Mechanical stability was greatly improved by removing residual oligomers from the material by a refining procedure. The refined polyurethane has characteristics favourable for blood pump applications.

Animals↗
PubMed1985

Multidisciplinary treatment for advanced nasopharyngeal carcinoma.

Of 30 nasopharyngeal carcinoma (NPC) cases seen from Jan. 1976 through Mar. 1984 at Tokyo Metropolitan Komagome Hospital, 19 previously untreated patients with more than 1-year follow-up were retrospectively investigated to confirm the effective treatment modality. The average age was 51 years; the ratio of male to female was 3.5:1. Fifteen were in stage IV, 3 in stage III, and 1 in stage II. These 19 patients were grouped into three treatment modalities: a) radiation +/- unplanned chemotherapy (RT +/- CM); b) radiation+unplanned cis-diamminedichloroplatinum (II)(CDDP)-based chemotherapy (RT + unplanned CDDP); and c) radiation + planned CDDP-based chemotherapy (RT + planned CDDP). Planned CDDP-based chemotherapy consisted of 20-50 mg/M2 CDDP, i.v. for 1 hr, 7.5-15 mg/body bleomycin (BLM), i.v. and/or 20-30 mg/body MTX, i.v. at weekly intervals with diuresis for at least 4 courses. Plasma platinum (Pt) concentration before and 1 hr after CDDP administration revealed a gradual increase due to accumulated protein-bound Pt, while free Pt remained transient. This regimen could be safely administered for at least 4 courses. The survival rate of RT + planned CDDP (n = 8) was 100% at maximum follow-up of 55 months, while RT +/- CM (n = 6) at maximum follow-up of 54 months and RT + unplanned CDDP (n = 5) at maximum follow-up of 38 months were 17 and 0%, respectively. Thus, we concluded that the most effective treatment modality for advanced NPC was RT+planned CDDP.

Adolescent↗
PubMed1985

Limited proteolysis of a chemically modified third component of human complement, C3, by cathepsin G of human leukocytes.

We have investigated the limited proteolysis of the third component of complement, C3, by a human leukocyte protease, cathepsin G, by using a chemically modified C3, which was prepared by treatment of C3 with methylamine and a fluorescent thiol reagent, N-(dimethylamino-4-methylcoumarinyl)-maleimide (DACM) and was thus named DACM-C3me. Although native C3 was hardly cleaved by cathepsin G, DACM-C3me was cleaved by cathepsin G into three major fragments, which were termed C3c-G (150,000 daltons, 150 kd), C3d-G (25 kd), and C3a-G (10 kd). C3c-G was composed of four disulfide-linked polypeptide chains of 75 kd, 35 kd, and two 25 kd. C3d-G and C3a-G were single-chain fragments derived from the alpha chain. The N-terminal sequence of C3d-G was determined as Thr-Glu-Asp-Ala-Val-, suggesting that cathepsin G released C3d-G by cleaving a Met-Thr peptide bond which is located at 19 residues toward the N-terminal from the cysteinyl residue forming an internal thiolester linkage in native C3. C3d-G, like C3d-K (a C3d fragment produced by the action of plasma kallikrein), was found to have bioactivities such as leukocytosis-inducing and immunosuppressive activities.

Amino Acid Sequence↗
PubMed1985

Herpes simplex virus and cytomegalovirus infections in burned patients.

Herpesvirus infections are commonly seen in immunosuppressed patients and may account for considerable morbidity and some mortality. We prospectively studied 52 patients with severe burn injuries in order to determine the prevalence of viral infections in this group of patients. Serologic testing was done each week to diagnose primary and reactivation infections. Twenty-seven of 52 patients (52%) became infected with either herpes simplex virus (HSV) or cytomegalovirus (CMV) or both. HSV infection was associated with older age, tracheal intubation, facial burn, inhalation injury, length of hospitalization, and the presence of full-thickness burn. CMV infection was associated with duration of hospitalization and full-thickness burn. Transfusion of blood products was not correlated with an increased incidence of primary or reactivation CMV infections. There was a significant correlation between the presence of these viral infections and bacterial sepsis (p less than 0.05). There was no significant association of HSV or CMV infections with mortality.

Adolescent↗
PubMed1985

Effects of Ca2+ antagonist, nicardipine, on experimental asthma with special reference to slow reacting substance of anaphylaxis.

Slow reacting substance of anaphylaxis (SRS-A) is an important chemical mediator of bronchial asthma. Leukotriene C4 is a component of SRS-A and is synthesized from arachidonic acid. Its synthesizing and releasing processes are found to be Ca2+-dependent. We developed an in vivo inhalation asthma model, mainly mediated by SRS-A, and elucidated the relationship between a Ca2+-antagonist, nicardipine, and SRS-A. In the asthmatic model, mediated by endogenous SRS-A induced by antigen inhalation, continuous intravenous infusion of nicardipine 7 micrograms/kg/min depressed the open airway pressure by about 60% compared with the saline-treated group. Inhibition of mean pulmonary resistance (RL) was about 50% and that of the inverted value of dynamic compliance (1/Cdyn) about 36%. However, the same concentration of nicardipine did not significantly effect the airway response in the asthmatic model induced by the inhalation of leukotriene C4. These results suggest that nicardipine, at the concentration used in the present study. did not block the direct effect of SRS-A on the smooth muscle, but blocked the Ca2+ influx required for the synthesis of SRS-A and its release.

Airway Resistance↗
PubMed1985

Surgical treatment of skin depigmentation caused by burn injuries.

Thin split-skin autografts of normal color were performed on depigmented skin caused by second- and third-degree burns in 32 patients. Repigmentation appeared in almost all the recipient areas soon after grafting and no depigmentation occurred again in the treated area.

Adolescent↗