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Biomedical subjects

R Murakami

Publications and source records attributed to R Murakami.

At least 181 records · Page 10Linked to original sources
PubMed1986

Proximal-distal sequence of development of the skeletal tissues in the penis of rat and the inductive effect of epithelium.

The penis of adult rats comprises the corpus cavernosum penis and the proximal and distal segments of os penis which are situated proximal-distally in this order. Androgens are necessary for the phenotypic differentiation of these tissues. In the present study, genital tubercular mesenchyme of foetal rats was recombined with or without homologous or heterologous epithelia and transplanted beneath the kidney capsule of syngeneic adult male rats, and the development of the corpus cavernosum penis and the os penis in the transplants was examined. Only in the presence of epithelia can the genital tubercular mesenchyme acquire the capacity for differentiation into the corpus cavernosum penis, the proximal segment of os penis, and the distal segment of os penis in this chronological order. The inductive effect of epithelium is a permissive step in the differentiation of the os penis of rat. The epithelium seems to be necessary for the process of rudiment formation of the os penis and the corpus cavernosum penis.

Animals↗
PubMed1985

[The diastolic pressure-volume relationship of the left ventricle--evaluation of canine isovolumetric contracting left ventricle].

Isovolumetrically contracting left ventricle of the anesthetized dog was used to evaluate the end-diastolic pressure-volume relationship [LVEDP (P)-LVEDV (V) relationship (curve)] following changes in heart rate, ischemia and administration of beta-adrenergic blocking drug. At the same time, relaxation indices were also obtained. Initial left ventricular volume was set at the end-diastolic pressure of 2.0 mmHg. Comparison of each parameters after intervention was done when each initial left ventricular volume was increased by 10 ml. With increase in heart rate, LVEDP increased significantly from 5.1 +/- 2.1 to 14.0 +/- 2.2 mmHg (at 160 bpm, p less than 0.02, vs 100 bpm) and to 24.0 +/- 1.0 mmHg (at 180 bpm, vs p less than 0.001, vs 100 bpm). Regional ischemia also increased LVEDP significantly from 6.4 +/- 1.4 mmHg to 12.8 +/- 4.1 mmHg (after 30 min, p less than 0.01, vs control) and to 14.1 +/- 4.7 mmHg (after 45 min, p less than 0.01, vs control). However, global ischemia produced by decreasing coronary perfusion pressure to 50 mmHg, or administration of propranolol (1.0 mg/kg) brought about no significant changes in LVEDP. Among the relaxation indices, peak negative dp/dt decreased significantly following global ischemia, regional ischemia and administration of propranolol (from 1101 +/- 131 to 733 +/- 49 mmHg/sec, p less than 0.01, from 888 +/- 425 to 268 +/- 94 mmHg/sec after 45 min, p less than 0.01 and from 562 +/- 160 to 291 +/- 100 mmHg/sec, p less than 0.01, respectively). On the other hand, time constant (T) of the left ventricular pressure fall was prolonged significantly following regional ischemia from 44.7 +/- 5.2 to 72.0 +/- 8.6 msec (after 30 min, p less than 0.001) and 95.4 +/- 26.0 msec (after 30 min, p less than 0.001) and 95.4 +/- 26.0 msec (after 45 min, p less than 0.001). Therefore, it is concluded that LV diastolic compliance decreases by tachycardia (160 and 180 bpm) and regional ischemia, while the changes of the relaxation indices were not necessarily parallel to those of the LV compliance.

Animals↗
PubMed1985

Association of second primary leukemias with the method of treatment of the first primary cancer.

A case-control study of the association between chemotherapy and/or radiotherapy for the first primary cancer and the second primary leukemia was made. All leukemia cases were collected from the cancer patients' file of the Osaka Cancer Registry which listed more than 220,000 cases during the 1965-82 period. Among the 2,765 leukemia patients, 46 had other (first) cancers. Two controls were selected from the cancer patients' file for each of the first primary cancers of 46 cases, with which they were matched in age, sex, cancer site, date of diagnosis, size of the treating hospital and survival period. Comparing the method of treatment of the first primary cancer in the cases and the controls, the proportion of patients treated by chemotherapy and/or radiotherapy was significantly higher among the cases than among the controls when the interval of the two primary cancers was 5 years or more.

Adolescent↗
PubMed1984

Relationship between lipids and angiographically defined coronary artery disease in Japanese patients.

The relationship between the severity and extent of coronary artery disease (CAD) and the lipid profiles was evaluated in 120 Japanese male patients, who underwent coronary angiography. Analysis of the lipid quartile distribution showed that the percentage of patients with significant CAD increased as the total cholesterol (TC) increased and high-density lipoprotein cholesterol (HDL-C) decreased. In addition, as the number of vessels with marked coronary artery stenosis increased, TC and TC/HDL-C increased while HDL-C decreased. However, within this population, triglyceride level, high blood pressure, and smoking were not significantly associated with coronary angiographic findings.

Adult↗
PubMed1984

Acute and chronic hemodynamic effects of the basic therapeutic regimen for congestive heart failure. Diuretics, low salt diet and bed rest.

The acute and chronic hemodynamic effects of the "basic regimen" for congestive heart failure (CHF), consisting of diuretics (furosemide) low salt diet and bed rest, was studied in 10 patients with CHF (all in NYHA class IV initially). In the acute stage, furosemide 80 mg i.v. effected rapid clinical improvement with reduction in ventricular filling pressures (VFP); however, no increase in cardiac-(CI) or stroke volume index (SVI) was observed. Subsequently, furosemide 80 mg/day, p.o. was administered for a mean of 30 days with the patients hospitalized on a low salt diet. During this period, their clinical condition was stable. The second hemodynamic study revealed that SVI increased (p less than 0.05) with reduction in VFP maintained. Next, low molecular weight dextran was infused to construct the Frank-Starling ventricular function curve (VFC) and this was compared with the VFC at the acute stage (during diuresis). As a whole, CI and SVI at the chronic stage were significantly increased (p less than 0.05) at equal pulmonary wedge pressures (PWP: mean 20 mmHg). Mean arterial pressure and systemic vascular resistance were decreased during the chronic stage. These findings suggest that the "basic CHF regimen" is effective on a chronic basis in improving left ventricular pump function through afterload and preload reduction, in addition to acute symptomatic relief due to a decrease in PWP.

Adult↗
PubMed1982

Conditions for "coronary steal" caused by coronary vasodilator in man.

This study was undertaken to assess the conditions necessary to cause the "coronary steal" phenomenon in human subjects. We studied 42 patients (36 males, 6 females, ages 27--70 years) with known or suspected coronary artery diseases using continuous monitoring of the changes in blood pressure and electrocardiogram, thallium-201 myocardial imaging and selective coronary arteriography. Dipyridamole in a dose of 0.4 mg/Kg was given as an intravenous infusion for 4 min and thallium-201 was injected at the 4th minute after completion of the dipyridamole infusion. None of the 20 patients without significant coronary artery disease complained of anginal chest pain or showed ischemic S-T segment depression. Dipyridamole images showed no perfusion abnormalities in 17 of the 20 patients. On the other hand, in 4 of the 22 patients with significant coronary artery disease, anginal chest pain accompanied with S-T segment depression occurred after the dipyridamole infusion. Dipyridamole images showed perfusion abnormalities in 18 of the 22 patients. The 4 patients who experienced an anginal attack had 3 vessel disease on the coronary arteriogram and showed regional perfusion defects on scintigrams corresponding to the regions receiving collaterals. Before the onset of pain, the double product (heart rate X systolic arterial pressure) was unchanged significantly but there was a reduction in the systemic blood pressure. The overall data exhibit the following conditions under which attacks of angina pectoris are induced by dipyridamole: 1) the presence of multiple vessel disease, 2) a fall in systemic blood pressure, and 3) regional malperfusion caused by dipyridamole.

Adult↗
PubMed1981

A study of brain development in low-birth-weight infants by computerized tomography.

Follow up study was conducted by brain CT scans on fullterm and premature infants for a period of 3 years following birth. The results were: 1. Low density areas were observed symmetrically in the frontal region in premature infants for 3 to 4 months after birth. However, they disappeared after 44 weeks of postconceptional age irrespective of either gestational age or birth weight. 2. At 40 to 56 weeks postconceptional age extracerebral space was most frequently found. The extracerebral space was found to exist longer in proportion to the shortness of gestational age and to a lower birth weight. 3. Some infants in the group who showed definite extracerebral space required persistent artificial ventilation for a long period. This may indicate that could exist a relationship between the occurrence of this particular space and hypoxia. 4. We consider that the extracerebral space in CT scan can be a useful parameter to assess the process of brain growth in premature infants.

Asphyxia Neonatorum↗
PubMed1980

[Long-term use of vasodilators in patients with congestive cardiomyopathy (author's transl)].

Three patients with congestive cardiomyopathy were studied for the acute and chronic hemodynamic effects of vasodilators using right heart catheterization, echocardiography and exercise tolerance test. All of the three were in congestive heart failure and were on digoxin and furosemide. Various vasodilators were used, which included isosorbide dinitrate, hydralazine, phentolamine and prazosin. Favorable acute hemodynamic effects were seen in all three. However, on continued use, all three showed evidence of tolerance to vasodilators by hemodynamic measurements. The first patient died in heart failure, complicated by pulmonary infarction. The second died suddenly after discharge from the hospital, while maintained in good control of the congestive heart failure. The third patient had recurrence of congestive heart failure after discharge, which was controled by the hospitalization and change to different vasodilator agents. Favorable hemodynamic effects were readily seen following vasodilators in patients with confestive cardiomyopathy. However, on chronic use some tolerance to the agents was observed. This needs to be investigated as to the mechanism so these agents can be more effectively utilized in these patients who are usually resistant to the conventional mode of therapy.

Adult↗