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Biomedical subjects

T Matsuda

Publications and source records attributed to T Matsuda.

At least 1,513 records · Page 84Linked to original sources
PubMed1984

Selective determination of alpha 2-plasmin inhibitor activity in plasma using chromogenic substrate.

In determination of antiplasmin activity of alpha 2-plasmin inhibitor (alpha 2 PI) using an amidolytic method, alpha 2-macroglobulin (alpha 2 M) in concentrations present in normal plasma inhibits the cleavage of chromogenic substrates by plasmin even if the reaction time between alpha 2M and plasmin is shortened as much as possible. The purpose of this study was to develop a new method to assay alpha 2 PI selectively with the chromogenic substrate S-2251 using an end-point method. The antiplasmin activity of alpha 2 M was destroyed by the addition of methylamine hydrochloride. In a case of congenital alpha 2 PI deficiency, antiplasmin activity determined with the previous method without the addition of methylamine was 20% of normal plasma, whereas the results obtained using this newly developed method was 5%. A statistically significant correlation between alpha 2 PI levels determined with this method and with a single radial immunodiffusion method was observed in plasma samples collected from 40 healthy subjects and 11 patients with disseminated intravascular coagulation (DIC). In two cases of DIC, in which markedly depleted levels of alpha 2 PI and normal concentrations of alpha 2 M were observed, antiplasmin activities measured without the addition of methylamine were higher than the ones measured immunologically, whereas the results obtained with the method described here were in accordance with the antigenicities of alpha 2 PI.

Aged↗
PubMed1984

Effects of immersion in cholesterol-lipid solution on the tensile and fatigue properties of elastomeric polymers for blood pump applications.

Tensile and fatigue properties were studied on three kinds of segmented polyether polyurethanes developed for blood pump applications. To study the effects of plasma constituents, specimens were immersed in a cholesterol-lipid solution whose composition is similar to that of plasma. The results obtained were compared with those observed in a saline solution which had been reported previously. Immersion in the cholesterol-lipid solution has influence on the mechanical properties of Toyobo TM5 polyurethane and Avcothane 51: Its effect is enhanced by cyclic deformation. Cholesterol-lipids change the mechanical characteristics of Avcothane 51 more remarkably than those of Toyobo TM5 polyurethane possibly because the former contains about 10% silicone. On the other hand, there is little effect of the constituents of the cholesterol-lipid solution on the static and dynamic mechanical properties of Biomer, although moisture and cyclic deformation have some influence on the mechanical characteristics.

Assisted Circulation↗
PubMed1984

Muscle stiffness changes during isometric contraction in frog skeletal muscle as studied by the use of ultrasonic waves.

In order to measure muscle stiffness changes with a high time resolution and with minimal disturbance to the contractile mechanism per se, we constructed an apparatus with which the propagation velocity of ultrasonic waves (MHz region) in the longitudinal or transverse direction was measured to serve as a measure of muscle stiffness. The longitudinal muscle stiffness started to increase on stimulation before the onset of isometric force, and reached a maximum before the peak twitch force. Analysis of experimental data indicated that, during an isometric tetanus, the increment of muscle longitudinal stiffness was about 6 X 10(7)N/m2, a value similar to those obtained by Truong (1974) and Ford et al. (1981) with sinusoidal vibrations (3 kHz) and length steps respectively. This suggests that the increment of muscle longitudinal stiffness during the activation of the contractile system results from the recruitment of an almost non-dispersive elastic component. In the case of transverse muscle stiffness, on the other hand, it started to decrease on stimulation before the onset of isometric force, and reached a minimum before the peak twitch force. Possible causes of this unexpected result is discussed in relation to the molecular mechanism of muscle contraction.

Animals↗
PubMed1984

Immunohistochemical study on the liver in autopsy cases with disseminated intravascular coagulation (DIC) with reference to clinicopathological analysis.

Immunohistochemical and clinicopathological studies were performed in 27 autopsy cases with indisputable DIC, which had been selected from 1,800 autopsy cases of elderly people based on the following two criteria; 1. presence of fibrin thrombi in glomeruli, and 2. presence of fresh patchy necrotic foci in myocardium and/or fibrin thrombi in splenic sinuses. A high incidence of liver lesions (22/27) was revealed in autopsy cases with indisputable DIC. The liver lesions could be classified into four groups. Group-I (Central degeneration) was characterized by massive precipitation of fibrin irregularly around the central vein, causing parenchymal damage. Group-II (Central necrosis), showed coagulation necrosis in the central zone due to circulatory disturbance caused by either shock as a cause of DIC or abrupt cessation of blood flow into the lobules following fibrin thrombus formation in vessels of Glisson's sheath. Both group-I and -II showed a short clinical duration of DIC. Group-III (Sinusoidal thrombosis), showed the presence of fibrin thrombi in sinusoids with mild parenchymal damage and long clinical duration of DIC. Group-IV (No thrombosis), showed neither parenchymal damage nor fibrin thrombi in sinusoids, but a long clinical duration of DIC.

Aged↗
PubMed1984

Effect of taurine on a benzodiazepine-GABA-chloride ionophore receptor complex in rat brain membranes.

Taurine at 10 mM had no effect on basal binding of [3H]diazepam to the membranes, while it significantly inhibited a GABA-stimulated binding of [3H]diazepam in cerebral cortex, hippocampus, but not in cerebellum. The inhibition by taurine in the presence of GABA (1 microM to 1 mM) was not competitive. At low concentrations (0.04 to 0.2 nM) the binding of [3H]propyl-beta-carboline-3-carboxylate, a ligand exhibiting higher affinity for type I than type II benzodiazepine receptors, was not enhanced by GABA, while the binding of higher concentrations (0.5 nM) was. This GABA enhancement of [3H]propyl-beta-carboline-3-carboxylate binding was also selectively blocked by taurine. Pentobarbital increased the binding of [3H]diazepam in a medium containing chloride and this effect was potentiated by taurine at 1-10 mM. These findings may be relevant to the modulatory role of taurine in the central nervous system.

Animals↗
PubMed1984

X-ray evidence for two structural states of the actomyosin cross-bridge in muscle fibers.

Biochemical data, stiffness measurements, and equatorial x-ray diffraction patterns provide evidence that actomyosin cross-bridges form in relaxed skinned rabbit fibers at low ionic strength (20 mM). In the present study we examined the structure of these cross-bridges by using two-dimensional x-ray diffraction. In contrast to rigor cross-bridges, which significantly weaken the myosin-based reflections characteristic of relaxed fibers at 120 mM ionic strength (notably the 86-A and 108-A layer lines and the 72-A and 143-A meridionals), the formation of low ionic strength cross-bridges produced only small changes in these reflections. In addition, these cross-bridges did not produce the additional intensity on the 59-A actin-based layer line near the meridian that is associated with rigor cross-bridges. However, the formation of low ionic strength cross-bridges caused the 215-A meridional reflection to decrease in intensity, as is also the case when rigor cross-bridges are formed. These observations show that the structure of the low ionic strength cross-bridge is significantly different from that of the rigor cross-bridge, and they raise the possibility that contractile force may be generated by a transition between these two actomyosin configurations.

Actomyosin↗
PubMed1984

Bleeding secondary to vitamin K deficiency in patients receiving parenteral cephem antibiotics.

Thirteen patients who were treated with cephem antibiotics developed blood coagulation disorders due to vitamin K deficiency. At the time of detection of prolongation of the prothrombin time, cefazolin was being administered in four cases, cefmetazole and latamoxef (moxalactam) in three cases each, and cefoperazone, cefpiramide and ceftazidime in one case each. Bleeding occurred in ten patients, but administration of vitamin K rapidly eliminated the prothrombin time prolongation and the haemorrhagic tendency. To date, we have not detected prothrombin time prolongation or a haemorrhagic tendency with cefotaxime, ceftizoxime, cefotiam, cefoxitin or cefsulodin. Thus, different cephem antibiotics show different effects on the prothrombin time.

Aged↗
PubMed1984

Isolation and characterization of rabbit H of the alternative complement pathway.

Rabbit factor H, a control protein of the alternative complement pathway, was isolated from rabbit serum by polyethylene glycol precipitation, DEAE-Sephacel chromatography, and gel chromatography on Sephadex G200. The protein migrated as a single-chain polypeptide with a molecular weight of 160,000 on sodium dodecyl sulfate-gel electrophoresis with Laemmli's buffer system, but hardly migrated into the gel with Fairbanks' buffer system. Physical and chemical properties of rabbit H were similar to those of human H, except that fragments produced by limited tryptic digestion from rabbit H had different molecular sizes from those produced from human H. Significant species-specificity was observed in the functional activity of factor H; activation of the alternative complement pathway was inhibited more efficiently with homologous H than with heterologous H. In contrast, factor H inhibited the hemolysis of homologous erythrocytes less than that of heterologous erythrocytes.

Amino Acids↗
PubMed1984

Design of pusher-plate-type left ventricular assist device based on mechanical analyses.

A permanently implantable left ventricular assist device (LVAD) pump of the pusher-plate type was designed based on mechanical analyses. A series of three different segmented polyether polyurethanes was utilized for the diaphragm, cannulae, and their blood-contacting surfaces, considering each material's characteristics. The span and thickness of the pump diaphragm were determined so as to minimize the stress developed by the bending and blood pressure forces. The inflow and outflow cannulae were designed using fundamental equations that describe the operation of a piston-type reciprocating pump. The pump diameter was determined considering the required flow for the average Japanese person. In vitro and in vivo experiments showed good pump performance, which satisfied the design specifications. No failure was observed in the designed diaphragm. The Hall effect sensor incorporated in the pump was very useful in monitoring the cardiac output of the pump.

Animals↗
PubMed1984

Contractile responses of mammalian cerebral arteries to 15-hydroperoxyarachidonic acid vary in the presence of fusaric acid and verapamil.

The effects of fusaric acid and verapamil on 15-hydroperoxyarachidonic acid (15-HPAA)-induced cerebral arterial contraction were examined. Addition to the tissue bath of 15-HPAA in concentrations ranging from 1 X 10(-7) to 3 X 10(-5) M caused a dose-dependent contraction in canine basilar, middle cerebral, posterior cerebral and human basilar or middle cerebral arteries. Fusaric acid and verapamil antagonized the 15-HPAA-induced contraction of these cerebral arteries by different mechanisms, in a dose-dependent manner. In the presence of 1 X 10(-3) M fusaric acid, the dose-response curves of cerebral arteries for 15-HPAA were antagonized in a noncompetitive manner. However, the responses to 15-HPAA were restored completely after removal of fusaric acid from the bathing solution. Fusaric acid did not antagonize the CaCl2-induced contraction. The concentration of verapamil which antagonized the 15-HPAA-induced contraction was a good fit to the concentration of this antagonist which antagonized the CaCl2-induced contraction. These findings indicate that the antagonism seen with fusaric acid manifests as a block of the sites specific for 15-HPAA and that the antagonistic actions of verapamil on 15-HPAA may be produced by the inhibition of calcium influx.

Adult↗
PubMed1984

Antidiuretic effects of oxotremorine microinjected into the hypothalamic supraoptic and paraventricular nuclei in a water-loaded and ethanol-anesthetized rat.

The effect of oxotremorine, a muscarinic agonist, on urine outflow compared with the effects of other cholinergic agonists and inhibitory effects of cholinergic antagonists upon the cholinergic actions were studied by microinjecting drugs stereotaxically, unilaterally into the supraoptic (SON) or paraventricular nuclei (PVN) in the hypothalamus of the rat which was loaded with water and anesthetized with ethanol. Oxotremorine decreased the urine outflow in dose- and time-dependent manners when microinjected into these nuclei. The median effective doses (ED50) were approx. 0.3 and 0.2 nmol in SON an PVN, respectively, being much less than ED50 values for nicotine. The time course of the antidiuretic effects was relatively slow, with the minimal urine outflow at approx. 30 min and the duration of one or longer hours. The antidiuretic effects of oxotremorine in these nuclei as well as the effects of acetylcholine and nicotine were completely blocked by pretreatment with atropine. The pretreatment with hexamethonium inhibited partially the effects of nicotine, but was unable to inhibit the effects of oxotremorine and acetylcholine. The data suggest that the antidiuretic effects of cholinergic agonists in SON and PVN are predominantly mediated through a muscarinic type of acetylcholine receptor. A possible mechanism for the antidiuretic effects is discussed.

Anesthesia↗
PubMed1984

[Surgical treatment and radiation therapy for glioblastoma multiforme, with special reference to intraoperative radiotherapy].

We studied the effects of increased-dose radiation therapy in terms of survival time and improvement in the quality of life in 50 glioblastoma patients with minimal residual tumors. 1) Intraoperative radiotherapy ( IOR , 1,000-2,000 rad) was applied in 13 cases; the 2-year survival was 41.6%. However, in 9 patients who had undergone macroscopic total removal the 2-year survival rate was 68.6%. 2) Wide resection with necrotomy after conventional external irradiation was used in 9 cases and conformation irradiation was added; their 2-year survival was 44.4%. 3) In 22 patients who received only conventional irradiation following surgery, the 2-year survival was 7.5%.

Adult↗