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Biomedical subjects

Y Koga

Publications and source records attributed to Y Koga.

At least 613 records · Page 34Linked to original sources
PubMed1982

[Exercise two-dimensional echocardiography: correlation between exercise induced asynergy and coronary artery lesions].

Exercise two-dimensional (2-D) echocardiography was performed in patients with suspected coronary artery disease, and exercise induced left ventricular asynergy was evaluated qualitatively and was compared with the coronary artery stenosis and electrocardiographic ST changes. Subjects were 12 patients with angina of effort, 8 patients with spontaneous angina, 8 patients with chest pain syndrome with the normal coronary artery, and 7 patients with hypertrophic cardiomyopathy (HCM). Cases with myocardial infarction were excluded from this study. 1) Left ventricular asynergy during exercise was observed in 10 and ST depression in 11 of 12 patients with angina of effort. In patients with spontaneous angina, left ventricular asynergy and ST depression during exercise were observed in 2 of 8 patients without anginal pain, and both patients had coronary artery stenosis of 90% or more. 2) Exercise induced asynergy was also observed in 4 of 7 patients with HCM without coronary artery stenosis. It seemed likely that the markedly hypertrophied myocardium and impairment of left ventricular compliance and relaxation may induce relative myocardial ischemia.

Adult↗
PubMed1982

[Cross-sectional echocardiographic visualization of the infarcted site in myocardial infarction: correlation with electrocardiographic and coronary angiographic findings].

Three dimensional assessment of the site of myocardial infarct was performed using cross-sectional echocardiography in 68 patients with old myocardial infarction. Patients with a history or electrocardiographic findings suggestive of double or multiple infarctions were excluded from the study. In patients with abnormal Q waves in V1 to V3, a regional wall motion abnormality (asynergy) was observed in the anterior portion of the interventricular septum (IVS) and the anterior free wall of the left ventricle (LV) which was extended from the base to apex. Most of them had a significant stenosis in the left anterior descending artery (LAD) distal to the first diagonal branch. Patients with Q waves in V1 to V5 or V6 showed extensive asynergy in the anterior IVS, anterior and lateral free walls of the LV extended from the base to apex. LAD stenosis proximal to the first diagonal branch seemed to be the corresponding coronary lesion. In patients with Q waves in V3 to V5 or V6, asynergy was limited to the apical half of the anterior wall of the LV. In patients with Q waves in II, III and a VF, asynergy was observed in the basal half of the posterior wall and the posterior portion of the IVS.

Coronary Angiography↗
PubMed1981

Characterization of withdrawal syndrome of morphine-dependent rats prepared by intermittent infusion technique.

The morphine withdrawal syndrome was studied in rats which had been made dependent on morphine administered by the intermittent infusion technique. Rats made rapidly dependent on morphine by an hourly infusion of 0.12-4 mg/kg/h showed a withdrawal syndrome when they were abruptly withdrawn, after infusion for 7 days, or when they were challenged by naloxone after infusion for 4 days. Abruptly withdrawn rats showed a marked weight loss and other mild symptoms. The weight loss seems to mainly due to anorexia, partly because it was attenuated by IV feeding throughout the withdrawal and partly because the fasted rats showed a weight loss comparable to the withdrawn rats. The naloxone-precipitated withdrawal syndrome showed characteristics, which, from their time course of incidence and their three groups; motor excitation, cholinergic signs, and others. These groups and their interrelationships were discussed. All characteristics were suppressed by deep anesthesia with ether or pentobarbital. A sudden fall in blood pressure was indicated in the anesthetized morphine-dependent rats immediately after the naloxone challenge. This suggests that the intrinsic withdrawal syndrome was progressing even under anesthesia.

Animals↗
PubMed1981

Assessment of physical dependence-inducing capacity of narcotic agonists and antagonists in rats by intermittent infusion technique.

Narcotics and other drugs were injected into the rat once an hour for about 1 week. Morphine and codeine showed physical dependency with a maintenance dose as low as 9.6 mg/kg/day. Development of dependence was also recorded in rats treated with cyclazocine (9.6 mg/kg/day) and pentazocine (96 mg/kg/day), and suspected in the levallorphan-treated (9.6 mg/kg/day) rats. Dependence on pethidine, which is known to be difficult to detect by the usual method in rats, also developed in this experiment (96 mg/kg/day), but it was estimated to be of lesser degree than that of codeine. Dependence on allazocine (9.6 mg/kg/day) and aminopyrine (96 mg/kg/day) did not develop. Barbital dependence (96 mg/dg/day) was induced, but it was distinguished from morphine-like drugs by the naloxone precipitation test and by substitution experiments. Cross-dependence between morphine and dependence-inducing drugs was investigated. Withdrawal weight loss in the morphine-dependent rats was suppressed or attenuated by pentazocine, pethidine, and codeine. Withdrawal weight loss in the rats dependent on cyclazocine, pentazocine, pethidine, or codeine was suppressed by morphine. Intermittent infusion of pentazocine at longer intervals induced dependence not as severe as that induced by 1-h infusion.

Animals↗
PubMed1981

An experience using spiral vein graft as arterial substitute.

In two patients wih aneurysmal changes due to arteriosclerosis in the axillary and the subclavian artery respectively, spiral vein grafts were used in a substitute for vascular reconstruction. After resection of the aneurysm, these vein grafts resulted in an excellent adaptation to the recipient vessel. Complicated techniques were not required and the construction time was minimal. Such an approach may be used even in adjacent sites to a joint.

Aneurysm↗
PubMed1981

Polysomnographic study of terminal sleep following delirium tremens.

Polysomnographic recording was performed during terminal sleep following delirium tremens (DT) in nine chronic alcoholics. After terminal sleep all the alcoholics fully recovered from DT. The duration of terminal sleep and DT differed among patients, but no significant correlation was found between the two. The most prominent feature in teh different stages of terminal sleep was a considerable decrease in slow wave sleep, especially stage 4 sleep. A slight decrease was observed in REM sleep, while stages 1 and 2 increased. A small amount of stages 1-REM and 2-REM was observed and a statistically significant correlation was noted between the appearance of these sleep stages. Intermittent wakefulness occurred in many patients. The disappearance of sleep cycles was observed in some patients. Therefore, terminal sleep following DT probably consists of recovery sleep from sleep deprivation caused by DT and disturbances of consciousness. Sleep cycles regularly occur in the former, but not in the latter.

Adult↗
PubMed1981

Mechanism of tracheal constriction by succinylcholine.

The purpose of this study was to identify the mechanism by which succinylcholine produced large increases in endotracheal tube cuff pressure in barbiturate-anesthetized dogs (n = 7). Cuff pressure was measured in vivo by a transducer connected to a fluidfilled, high-volume, low-pressure cuff. Intravenous succinylcholine, 0.5 and 1 mg/kg, produced mean increases in cuff pressure of 12 +/- 2 (+/-SE) and 27 +/- 5 cm H2O, respectively, which reached peak effect in 1 to 3 min and declined slowly over the next 10 min. Bilateral vagotomy, intravenous administration of atropine (0.2 mg/kg) and hexamethonium (5 mg/kg) prevented or terminated succinylcholine-induced increases in cuff pressure. Isolated preparations from an additional three dogs were employed to study the direct actions of succinylcholine on trachealis muscle in vitro. In organ baths, succinylcholine (10(-6) to 10(-3) M) did not contract canine trachealis muscle, and concentrations of 10(-5) M and above significantly relaxed carbamylcholine-induced contractions. The authors conclude that succinylcholine elicits contraction of trachealis muscle by a stimulant action on parasympathetic pathways rather than by a direct action on airway smooth muscle. Since vagotomy prevented the succinylcholine response, the site of stimulant action is not at autonomic ganglia.

Animals↗
PubMed1981

Molecular pathology of cancer cell adhesiveness.

A new cell surface-associated adhesive glycoprotein with a molecular weight of 70,000 was separated from differentiated rat ascites hepatoma cells forming cell islands in vivo (but not from undifferentiated rat ascites hepatoma cells present as single cells in vivo) and highly purified by chromatography; it was synthesized by the cells and localized on the cell surface. Its synthesis began to rise rapidly and reached its peak in 24 hr cultivation, i.e., a 10-fold increase. This substance induced not only aggregation but also adhesiveness of the cells characterized by junctional complexes including tight junctions, desmosomes, and intermediate junctions, closely resembling the frequency and distribution of junctional complexes observed on the above cell islands. Its potency was inhibited specifically by D-mannose and alpha-methyl-D-mannoside; the numbers of the binding sites per cell were calculated as 6 x 10(5). Its activity was concerned with the protein portion of the molecule, and not with the carbohydrate portion. Thus, it seemed reasonable that the adhesive glycoprotein may play a key role in the cell adhesiveness and island formation. In contrast, serum-associated adhesive glycoprotein, separated from normal rat serum, could aggregate the cells but not develop junctional complex.

Animals↗
PubMed1981

Purification and characterization of carcinoembryonic antigen-related antigens in normal adult feces.

We tried to purify carcinoembryonic antigen (CEA)-related antigens in normal human feces and found that, besides nonspecific cross-reacting antigen (fecal NCA), there are three other molecular species of CEA-related antigens which have been inclusively called normal fecal antigen (NFA). These were designated normal fecal antigen 1 (NFA-1), normal fecal antigen 2 (NFA-2), and normal fecal cross-reacting antigen (NFCA), respectively. Among these antigens, NFA-1, NFA-2, and fecal NCA were isolated in pure form. NFCA has not yet been obtained in pure form but was identified as an antigen different from three other antigens. All antigens were glycoprotein in nature and migrated electrophoretically in the beta region. Their molecular weights were estimated to be 20,000 to 30,000 for NFA-1, 160,000 to 170,000 for NFA-2, and 80,000 to 90,000 for NCA, respectively. NFA-2 had amino acid and carbohydrate compositions similar to those of CEA. The results obtained by immunodiffusion analyses of antigenic determinants indicate that CEA and NFA-2 can be divided into four antigenic moieties: the first one is distinctive for CEA (cancer determinant) or NFA-2 (NFA-2-distinctive determinant); the second one corresponds to NFA-1 (NFA-1 determinant); and the remaining two moieties are present on NFCA, one of which is characteristic for NFCA (NFCA determinant) and the other of which is shared with NCA (NCA-common determinant).

Antigens↗