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Biomedical subjects

Y Imamura

Publications and source records attributed to Y Imamura.

At least 325 records · Page 18Linked to original sources
PubMed1989

[A case of sick sinus syndrome, considered to develop to atrial standstill].

A 25 year old man was admitted to our hospital because of dizziness and bradycardia. Physical examination was normal except for an irregular pulse of 90 beats/min. Chest X-ray film showed no cardiomegaly and no pulmonary congestive changes. ECG showed 2:1 or 3:1 atrial flutter on admission. After atrial flutter was terminated spontaneously, ECG revealed absent P waves, a QRS interval of 0.10 seconds, and A-V junctional rhythm with irregular R-R interval ranging from 1.20 to 2.12 seconds. At times, cardiac arrest was noted. Esophageal electrocardiogram also failed to demonstrate atrial activity while A-V junctional rhythm continued. Mitral valve echocardiogram lacked A point, and then ä waves were absent in both the right atrial and pulmonary capillary pressure recordings. Transient atrial standstill was suspected from these findings, so that electrophysiological study was performed. Right atrial electrogram revealed complete absence of atrial activity. His bundle electrogram revealed H-V prolongation [80-83 msec]. Right atrial pacing was attempted at several atrial sites, including the high lateral, middle lateral, low lateral right atrium, and low right atrial septum. Atrial activity could be elicited with stimulus strength of 3 to 5 volts. These atrial pacing thresholds were mild or moderately higher than usual. After the cessation of atrial pacing at 90 beats for two minutes, the recovery time of the first beat prolonged to 8.46 second. We considered that this case was sick sinus syndrome in young adult which revealed generalized disturbance of conduction system including the atrial muscle, and would develop to atrial standstill in the near future.

Adult↗
PubMed1989

[Surgical treatment of patients with triple valvular heart disease--a clinical study of triple valve replacement].

Triple valve replacement were performed on 14 cases from 1972 to 1987 in our department in Nihon University School of Medicine. Hemodynamic data and the function of other organs were analysed. 5 cases were dead. Causes of death were LOS in four and respiratory failure in one. Although preoperative clinical status were class III and IV in NYHA, postoperative clinical status improved in I and II except dead cases. There were significant differences between pre and postoperative valves of PAm, PCWP and CI, but of RAm RVEDP and EF. The reason why these cardiac function did not recover enough was myocardial degeneration. The respiratory, renal and liver function was clearly improved after operation except hemolysis. In conclusion, it is recommended that, in cases of severe triple valve disease, triple valve replacement should be performed with SJM valve to get satisfactory hemodynamic improvement.

Adult↗
PubMed1989

Endoscopic studies on the superficial spreading type of early gastric cancer.

Twenty eight cases out of 230 cases of early gastric cancer showed the superficial spreading type of early gastric cancer. Seventeen stomachs (60.7%) were compatible to the endoscopic finding of spreading cancerous regions, even to macroscopic and microscopic ones. Other 11 cases were not corresponded clinicopathologically to the infiltrated lesions. These 11 cases were studied on the superficial spreading lesions respectively. They were divided into three groups and compared each other micro- and macro-scopically and endoscopically. Group I contained 6 cases, compatible to micro- and macro-scopic findings but not to endoscopic ones. Endoscopic overdiagnosis may be redness and overflow of white fur and underestimate by a few cancer cells superficially in the mucosae, slight difference in height at the margin of II c and cancer without exposure. Group II was similar microscopic and endoscopic findings but not compatible macroscopically. Both cases in group II were overestimated macroscopically at the infiltrated edge because of color change in mucosae but endoscopically diagnosed by changes of color and gastric area. Group III contained 3 cases of microscopic characteristics and not compatible to macroscopic and endoscopic ones. Endoscopic underdiagnosis may be based on a few cancer cells superficially in normal mucosae and on less depressed lesions. These clinicopathological studies might be worthy to clarify the endoscopic and pathologic discrepancies of infiltrating areas by early gastric cancer, and might improve endoscopic techniques of the gastric mucosal observation.

Adult↗
PubMed1989

Lectin histochemistry in rat thyroid tumours.

The thyroid tumours and background goiterous and adenomatous lesions induced in rats with diisopropanolnitrosamine (DIPN) plus methylthiouracil (MTU), and regenerative thyroid tissues after wounding were studied by lectin histochemistry. Ten weeks after cessation of the carcinogen treatments, carcinomas invading the surrounding tissues and blood vessels (13/20) and papillary micronodules (11/20) were formed in the thyroid tissues. In general, the carcinoma lesion was solitary, and the papillary micronodules were multiple in a single thyroid gland. Among the lectins tested, Maclura pomifera (MPA) and Solanum tuberosum (STA) showed specific binding with both carcinoma and papillary micronodule lesions, but not with the background goiterous and adenomatous lesions and regenerative thyroid tissues. The former both lesions showed higher labelling indices with BUdR or 3H-thymidine and poorer thyroglobulin accumulation than the latters, thereby indicating their enhanced proliferative capability and depressed potency of cyto-differentiation. The common cytological and histochemical properties of carcinoma lesions and papillary micronodules allow us to regard the latter as pre-invading carcinoma lesions. The lectins MPA and STA may be, therefore, used as the specific markers of malignancy in rat thyroid carcinogenesis.

Animals↗
PubMed1988

Phasic coronary artery flow velocity determined by Doppler flowmeter catheter in aortic stenosis and aortic regurgitation.

Phasic coronary artery flow velocity was recorded in 14 patients with aortic regurgitation (AR), 4 with aortic stenosis, 61 with other heart diseases and in 2 normal subjects by means of a bidirectional Doppler flowmeter catheter. The normal pattern of the phasic coronary artery flow velocity was characterized by a small forward flow during systole (S wave) and a large forward flow during diastole (D wave). The phasic coronary artery flow velocity in patients with AR showed increased S wave and decreased D wave. The area under the S-wave curve divided by the area under the D-wave curve (S/D ratio) in patients with AR increased (left coronary artery flow velocity 0.66 +/- 0.39, p less than 0.05; right coronary flow velocity 0.79 +/- 0.36, p less than 0.01) as compared with the S/D ratio in patients with other heart diseases (left coronary flow velocity 0.32 +/- 0.12; right coronary artery flow velocity 0.38 +/- 0.17). There was a tendency toward a relative positive correlation between S/D ratio values and AR cineangiographic grades. Decreased S/D ratios were observed in 4 patients with aortic stenosis. It is believed that no reports exist on phasic coronary flow velocity recorded in conscious patients who had aortic valve disease.

Adult↗
PubMed1988

Correlation between plaque size and genetic variation of type 3 poliovirus from a vaccinate.

Vaccine strain derivatives could be serially isolated from the feces of a healthy infant for about 30 days after the second administration of a trivalent poliovirus vaccine. These were all identified as poliovirus type 3, and no other types were detected. The titer in feces increased gradually until day 19, when it reached a maximum, after which it decreased. The plaque size altered roughly in parallel with the changes in the titer. On day 11 it began to increase, becoming the highest abruptly on day 15, and then fell again. Oligonucleotide mapping analysis of RNAs of isolated viruses showed that the samples from days 1 and 11 exhibited the same patterns as those shown by the vaccine strain RNA. However, on day 15 many of the preexisting spots had decreased, and new ones appeared. On day 27, the pattern was again similar to that of the original virus, rather than that of the day-15 virus. A nonmetric distance scaling and cluster analysis suggested that all the strains were derived from the same origin and that the polioviruses on days 1, 11, 21, and 27 had closer relationships, but the poliovirus on day 15 was different.

Feces↗
PubMed1988

The heterogeneous distribution of argininosuccinate synthetase in the liver of type II citrullinemic patients. Its specificity and possible clinical implications.

The authors analyzed the heterogeneous distribution of hepatic argininosuccinate synthetase of type II citrullinemia in reference to its specificity and clinical implications. The low content of the enzyme in the liver of type II citrullinemic patients is associated with two kinds of the enzyme distribution that can be visualized by means of an immunohistochemical method (Saheki and colleagues. Biomed Res 1983;4:235-238). Among the 25 cases of type II citrullinemia examined, 11 exhibited homogeneous distribution of the enzyme, as in the control livers. On the other hand, 14 presented the clustered distribution, in which the hepatocytes stained positively with antisera to argininosuccinate synthetase formed a cluster among the poorly stained cells. No clustered distribution of the enzyme was present in the liver of control patients either with or without liver diseases. No clustered distribution of arginase and aldolase B was observed even in the liver of type II citrillinemic patients. These results suggest that clustered distribution is specific to argininosuccinate synthetase in the liver of type II citrullinemic patients. From considerations concerning the heterogeneous distribution of the enzyme and certain clinical parameters as well, the authors suggest that the clustered type in type II citrullinemia has a less favorable prognosis with regard to fatality.

Argininosuccinate Synthase↗
PubMed1988

The effect of metoclopramide on the absorption and pharmacology of chlorpromazine in the rat.

The mechanism of interaction between metoclopramide (MCP) and chlorpromazine (CPZ) has been examined in rats. MCP given intraperitoneally 30 min before orally administered CPZ significantly enhanced the cataleptic and hypothermic effects of CPZ, and also initially increased its plasma and brain concentrations. However, MCP had no effect on the plasma and brain concentrations of CPZ given as an intravenous bolus, indicating that MCP interacts with CPZ during its intestinal absorption. Furthermore, co-administration of MCP (i.p.) with CPZ (p.o.) markedly accelerated gastric emptying compared with CPZ alone, and MCP (i.v.) did not alter the uptake of CPZ by the intestinal membrane. Therefore, it is concluded that MCP causes an increase in the rate of CPZ absorption, by accelerating the gastric emptying.

Animals↗
PubMed1988

Metabolic reduction of acetohexamide in rat kidney: sex difference and effect of streptozotocin-induced diabetes.

The acetohexamide reductase activity in 10000 x g supernatant fluids of kidney homogenates was significantly higher in male than in female rats. Although difference in activity of acetohexamide reductase in the cytosol between the sexes was not observed, the activity in the microsomes was considerably higher in male than in female rats. These findings indicate that the microsomal enzyme plays an important role in the sex difference of acetohexamide reduction by 10000 x g supernatant fluids of kidney homogenates. The sensitivities to inhibitors of microsomal acetohexamide reductase were different from those of cytosolic acetohexamide reductase. Furthermore, streptozotocin-induced diabetes significantly decreased acetohexamide reductase activity only in the kidney microsomes of male rats, resulting in the abolishment of the sex difference of acetohexamide reduction by 10000 x g supernatant fluids of kidney homogenates.

Acetohexamide↗
PubMed1988

Supraventricular tachycardia in a patient with Lown-Ganong-Levine syndrome associated with apical hypertrophic cardiomyopathy.

Electrophysiologic study of a 55-year-old patient with Lown-Ganong-Levine syndrome associated with apical hypertrophic cardiomyopathy is reported. The patient had a history of recurrent attacks of tachyarrhythmia and his electrocardiogram showed a short P-R interval (0.10 sec) with narrow QRS complex and left ventricular hypertrophy with giant negative T waves. His cineangiogram showed severe apical hypertrophy. An electrophysiologic study was performed. The results of programmed atrial pacing show the existence of the dual A-V nodal pathways. The A-H interval at rapid atrial pacing increased maximally by 103 msec. Atrial stimulation could depolarize parts of the atrium without altering the supraventricular tachycardia. These findings suggested that preferential rapidly conducting A-V nodal and intranodal reentry are the responsible mechanisms in this reciprocating tachycardia. We conclude that the short P-R interval was due to intranodal reentry through the dual A-V nodal pathways. To our knowledge, a case of Lown-Ganong-Levine syndrome with apical hypertrophic cardiomyopathy has not been previously described in the literature.

Cardiac Catheterization↗