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Biomedical subjects

T Koeda

Publications and source records attributed to T Koeda.

At least 91 records · Page 5Linked to original sources
PubMed1989

Relation between mixed venous blood oxygen saturation and cardiac pumping function at the acute phase of myocardial infarction.

In this study, we monitored changes in the mixed venous blood oxygen saturation (Sv-O2) level of 45 patients with acute myocardial infarction and compared these results to the traditional parameters. The Sv-O2 level was found to correlate well with the clinical course of patients and their hemodynamic conditions. The mean Sv-O2 level of the group having congestive heart failure (53.3 +/- 8.4%) was found to be statistically lower than those without (69.8 +/- 5.6). Furthermore, patients whose Sv-O2 level was lower than 60% were found to be at greater risk for heart failure and a very high mortality rate. Patients were classified into four subsets according to Forrester's hemodynamic classification; their Sv-O2 levels were 70.7 +/- 4.1% (I: 23 cases), 54.7 +/- 6.9% (II: 8 cases), 55.8 +/- 9.4% (III: 10 cases), and 47.0 +/- 8.0 (IV: 4 cases), respectively. A severe relationship between pulmonary capillary wedge pressure and Sv-O2 having a correlation coefficient of r = -0.64 was observed, and a logarithmic curvilinear relation between cardiac index approximately Sv-O2, stroke volume index approximately Sv-O2 and left ventricular stroke work index approximately Sv-O2 was also evident. When the decrease in the Sv-O2 level was more than 5%, it always showed a significant decrease in the cardiac index. This study suggested tht continuous monitoring of the Sv-O2 level revealed simultaneous changes in the hemodynamic state, which lead to the assistance and aid for treating patients with critical conditions of acute myocardial infarction. In such circumstances, it was noted that the Sv-O2 level should be maintained above 60% in order to stabilize the hemodynamic state.

Aged↗
PubMed1989

Effect of aminoglycoside antibiotics on the electrical stimulation-induced contractile response of the guinea-pig ureter.

Using electrical stimulation, we first investigated whether the movement of ureteral smooth muscle of the guinea-pig was myogenic in its control, or neurogenic. We then investigated the effects of aminoglycoside antibiotics (kanamycin, bekanamycin and ribostamycin) on the movement of ureteral smooth muscle induced by electrical stimulation. In these investigations, each ureter removed from the animal was cut into three approximately equal-sized segments, which are an upper segment (kidney side), a middle segment and a lower segment (urinary bladder side). Each segment was mounted in an organ bath filled with Krebs solution and the mechanical response induced by electrical stimulation of each segment was recorded isometrically. Each one of the upper, the middle and the lower segments was stimulated with rectangular pulses (50 volt, 0.1-3 msec durations, 40 Hz) for a period of 2 sec. Of all segments tested (ten in each group), none showed any response to the stimulation with pulses below 0.5 msec duration. While 2-3 segments out of ten of the upper, the middle and the lower ureteral segments showed a contractile response to stimulation with pulses of 1 msec duration, the rest of the segments showed no response to the same stimulation. This contractile response was not inhibited by tetrodotoxin which is known to block the nerve-mediated response. And also, all the ten samples of each upper, middle and lower segment never failed to show a contractile response to stimulation with pulses of 2 msec and 3 msec duration. Various drugs which are already known to block the nerve-mediated response (i.e., atropine, guanethidine, phentolamine, propranolol and tetrodotoxin) were tried, but none of them had an inhibitory effect on the contractile response. On the other hand, each one of kanamycin (KM), bekanamycin (AKM) and ribostamycin (RSM) in concentrations of 1 x 10(-5) g/ml-1 x 10(-3) g/ml produced a concentration-dependent decreasing effect in the magnitude of the electrical stimulation-induced contractile response of the ureteral segment. In addition, the decreasing effects of these antibiotics were also observed in the tetrodotoxin. From these results, we concluded that the contractile response of the ureter may be myogenic in its control, and the aminoglycoside antibiotics, KM, AKM and RSM, may act directly on the ureteral smooth muscle so as to decrease its contractile response.

Animals↗
PubMed1988

Changes in the lateral ventricle with the head position: ultrasonographic observation.

Ultrasonographic examination was performed in 13 preterm, 10 normal term and 3 term brain-damaged infants to evaluate changes of the ventricular width with the head position. The lower side of the frontal horn was narrowed and the upper side dilated in all preterm and brain-damaged infants. These changes of the ventricular width may be due to gravity and soft brain. Therefore, it is very important to consider the transformation of the lateral ventricles with the head position when asymmetry of the lateral ventricle is identified in infants showing prematurity or brain damage.

Brain Damage, Chronic↗
PubMed1988

Myopathy and encephalopathy in chick embryos experimentally infected with Akabane virus.

Chick embryos infected with Akabane virus by the yolk sac route at 6 days of incubation developed polymyositis and encephalitis. At 3 to 7 days after inoculation, skeletal muscles had myotubule degeneration, clumping of muscle cell nuclei, and infiltration of heterophils; dysplasia and aplasia were evident at 9 to 15 days after inoculation. Changes in the cerebral neostriatum and optic lobes at 2 to 11 days after inoculation included necrosis of primordial nervous tissue, hemorrhages, and hyperplasia of the vascular endothelial cells. Cavities were in nervous tissue subsequent to encephalitis. Hydranencephaly and vascular wall thickening were found 13 and 15 days after inoculation. Embryos infected intravenously at 15 days incubation had foci of encephalitis 3 to 6 days after inoculation, including neuronal degeneration, neuroglial hyperplasia, vascular endothelial proliferation, and heterophil infiltration.

Anencephaly↗
PubMed1987

Changes in hemodynamics due to the contrast medium during left ventriculography.

Seventeen patients with heart diseases examined by left ventricular angiography were divided into two groups consisting of those with a clinical history of heart failure (CHF+) and those without (CHF-). Changes in hemodynamics, circulating blood volume, and plasma volume due to injection of the contrast medium were studied, and the following results were obtained. Both the CHF- and CHF+ groups showed an increase in heart rate after injection of the contrast medium, but a statistically significant difference (p less than 0.05) was noted only at one and two minutes after angiography in both groups. Left ventricular systolic pressure decreased after injection of the contrast medium in both groups, but the CHF+ group required a longer time for recovery. In the CHF- group, the left ventricular end-diastolic pressure increased slightly after injection of the contrast medium, but in the CHF+ group it increased markedly with a statistically significant difference (p less than 0.01). Stroke volume, measured by a noninvasive, continuous cardiac output monitor according to the impedance method, increased upon injection of the contrast medium in the CHF- group. However, in the CHF+ group it decreased, although no statistically significant difference was noted in either group. Cardiac index increased markedly upon injection of the contrast medium in the CHF- group with a statistically significant difference (p less than 0.01), but hardly any change was observed in the CHF+ group.(ABSTRACT TRUNCATED AT 250 WORDS)

Angiocardiography↗
PubMed1986

Immunopathological study related to myoglobin in myasthenic and non-myasthenic thymuses.

Twelve biopsied thymuses taken from 4 cases with myasthenia gravis (MG group) and 8 cases without myasthenia gravis (control group) including 2 thymoma cases in each group were immunopathologically investigated in relation to myoglobin (Mb). Mb positive cells of various degrees were detected in all thymuses of both groups, and immunoelectron microscopical examination disclosed that Mb positive cells corresponded to interdigitating reticulum cells and myoid cells in non-neoplastic thymuses, and neoplastic epithelial reticular cells in thymomas. Anti-Mb antibody staining by direct immunoperoxidase technique revealed positive localization to the lymphoid cells in the thymuses of 2 cases of MG group with thymoma. In addition, indirect immunofluorescent study with the serum of each case which was applied to the normal human skeletal muscle, showed positive staining of the sarcoplasm in 3 cases of MG group, including 2 thymoma cases, and using peroxidase labeled serum IgG F (ab')2 of the same patients this anti-muscle antibodies were proved to be against both postsynaptic cytosol and sarcoplasm of the extraocular muscle of the guinea pig. From these results, it was suggested that Mb may conduct itself as a homologous antigen between the thymus and the skeletal muscle in the myasthenic patient with thymoma, and in the thymus the interdigitating reticulum cell, the myoid cell, or the neoplastic epithelial reticular cell may retain or produce Mb as an antigen-presenting cell.

Adult↗
PubMed1986

Effects of taurine on neutrophil function in hyperlipidemic rats.

In dietary hyperlipidemic rats, an increase in serum lipid level may cause an increase in membrane lipid level of the neutrophils, and phagocytosis and bactericidal capacity may be thereby lowered. Treatment with taurine (470 mg/kg/day, p.o.) strengthened the bactericidal capacity of neutrophils which was decreased by cholesterol diet feeding, as the capacity was stronger on the 40th day than that in animals fed laboratory chow. The results suggest that taurine may play an important role in the mechanism of host defense through the neutrophil function.

Animals↗
PubMed1986

A note on responses of isolated guinea-pig tracheal strip preparation to electrical stimulation.

Authors observed the mechanical response of the tracheal muscle to electrical stimulation using only one transverse strip preparation of isolated guinea-pig trachea, 4-5 mm in width, which included only one tracheal muscle strip. The effects of various pharmacological agents on these responses were also investigated. A biphasic response which is a contractile response followed by a relaxing response usually appeared when the preparation was stimulated with rectangular pulses (50 volt, 0.5 msec) at 40 Hz for a period of 5 sec. A monophasic contractile response also appeared, only rarely but this response was shifted to the biphasic response as the resting tonus level of the preparation gradually increased in the course of the experiment. When the preparation was stimulated electrically at intervals of 15 min, the resting tonus level of the preparation gradually decreased and it subsequently reached a stable state. Then the amplitude of contractile response and depth of relaxing response in the biphasic response evoked by electrical stimulation of constant condition were, respectively, almost constant, whenever the preparation was stimulated at intervals of 15 min. The amplitude of monophasic contractile response which appeared only rarely was relatively constant to every trial of electrical stimulation throughout the experiment. The amplitude of contractile response and depth of relaxing response in the biphasic response were 283 +/- 65 mg (mean +/- SD, n = 10) and 293 +/- 93 mg (mean +/- SD, n = 10), respectively. The monophasic contractile response was abolished by atropine (5 X 10(-7) g/ml) or tetrodotoxin (2 X 10(-7) g/ml). The contractile response in the biphasic response was abolished by atropine (5 X 10(-7) g/ml). In the presence of atropine (5 X 10(-7) g/ml), therefore, only the relaxing response appeared. This relaxing response was respectively reduced by guanethidine (1 X 10(-5) g/ml-1 X 10(-6) g/ml) and propranolol (1 X 10(-5) g/ml-1 X 10(-6) g/ml), but complete inhibition was never seen. These findings suggest that the excitatory innervation is cholinergic and the inhibitory innervation is both adrenergic and non-adrenergic. In addition, from the results of this work it is clear that the preparation used by the authors are good enough to observe the electrical stimulation-induced response of the preparation.

Animals↗