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Biomedical subjects

R Murakami

Publications and source records attributed to R Murakami.

At least 145 records · Page 8Linked to original sources
PubMed1992

[Surgical treatment of acute aortic dissection in the aged: a case report].

A 77-year-old woman with Stanford type A acute aortic dissecting aneurysm was successfully treated by the sutureless technique using arringed intraluminal graft. A month after the operation, re-dissection to the distal abdominal aorta occurred. Because of the poor condition of the patient and her great age, we chose an antihypertensive therapy instead of a reoperation. Two years after the operation this patient leads a sound life without any symptoms. In a case of acute aortic dissection of the aged, special consideration may be allowed to a surgical method and a decision-making for a reoperation.

Acute Disease↗
PubMed1991

Superior vena cava flow and tricuspid anular motion after cardioversion of atrial fibrillation, and role of right atrial relaxation on systolic venous return.

To determine whether atrial relaxation or systolic descent of the tricuspid anulus is the predominant factor determining systolic venous return, 22 patients with atrial fibrillation were studied. Venous return (i.e., superior vena cava (SVC) flow) was measured using pulsed Doppler echocardiography. Systolic descent of the tricuspid anulus (i.e., total excursion of tricuspid anulus during systole) was also measured using echocardiography. Serial examinations were performed before and after cardioversion of atrial fibrillation in 15 patients. In 11 patients, both the total excursion of the tricuspid anulus and SVC flow were examined in relation to the ratio of the preceding to the pre-preceding RR interval (R2/R1). Systolic forward flow of SVC increased as the ratio of late diastolic to total excursion of the tricuspid anulus (i.e., right atrial systolic function) increased. It correlated significantly with the ratio of late diastolic to total excursion of the tricuspid anulus but not with total excursion. Total excursion of the tricuspid anulus correlated significantly with R2/R1, but systolic forward flow of SVC did not. These results indicate that atrial relaxation rather than systolic descent of the tricuspid anulus was the predominant factor determining systolic forward flow in the SVC.

Atrial Fibrillation↗
PubMed1991

Vitamin D receptors in heart: effects on atrial natriuretic factor.

We report that receptors for vitamin D exist in distinct regions of the heart in female and male mice, predominantly in the right atrium where most of the cardial atrial natriuretic peptide (ANF) is produced. Tritiated 1,25-dihydroxyvitamin D3 (1,25-D3, vitamin D, soltriol) and ANF are colocalized in nuclei and cytoplasm respectively in identical cardiomyocytes. Changes of ANF tissue and blood levels under dietary deficiency and treatment with 1,25-D3 suggest direct genomic actions of vitamin D on myoendocrine cells of the atrium for the regulation of ANF manufacture and secretion. These results were obtained by combining thaw-mount autoradiography with immunocytochemistry using tritiated 1,25-D3 and an antibody against rat ANF. This antibody was also used in a radioimmunoassay to determine atrial natriuretic factor in plasma, atria and ventricles of normal or vitamin D-deficient mice.

Animals↗
PubMed1991

Angina pectoris due to possible vasospasm of small coronary arteries.

Recently, the presence of vasospasm in small coronary arteries is speculated in animals and humans. A 40-year-old female patient complained of chest pain at rest. Left ventriculogram showed normal wall motions. Left and right coronary arteries were also normal. After methylergometrine maleate was selectively administered to a right coronary artery, she complained of chest pain, and ST-segment elevation was detected in leads II, III, and aVF of ECG. Right coronary arteriography was performed immediately, but no coronary stenosis was found. The next day, methylergometrine maleate was again administered intravenously and the patient complained of chest pain, but no ischemic changes were observed in ECG. Thallium-201 myocardial scintigraphy followed immediately. Apical perfusion defect was detected in stress image. In the delayed image, it showed complete redistribution. Three days later, catheterization and scintigraphy were performed at the same time. When methylergometrine maleate was administered to the left coronary artery, she complained of chest pain within a few minutes of the injection; however, ECG remained unchanged. 201Tl myocardial scintigraphy was performed immediately. In the stress image, it showed apical perfusion defect as shown in the intravenous methylergometrine maleate injection study. It also showed complete redistribution in the delayed image. Apical perfusion defect can be attributed to myocardial ischemia of left coronary artery, which are too small to be detected by conventional coronary arteriography. Vasospasm in small coronary arteries may be involved in this phenomenon.

Adult↗
PubMed1991

The detection of myocardial ischemia by thallium-201 myocardial scintigraphy in patients with multiple coronary arterioventricular connections.

The question of whether myocardial ischemia could be induced in 5 patients with multiple coronary arterioventricular connections by thallium-201 (201Tl) exercise stress myocardial scintigraphy was investigated. Both ST-T changes on ECG and transient myocardial perfusion defects in myocardial scintigrams were observed in 2 patients (40%). In previous reports, all multiple coronary arterioventricular connections, which were shown in angiograms, have been regarded as either Thebesian veins or embryonic sinusoids. However, it is unlikely that Thebesian veins cause myocardial ischemia judging from anatomy. If the vessels cause myocardial ischemia, they should be regarded as multiple coronary arterioventricular fistula. Angiography itself cannot differentiate multiple coronary arterioventricular fistula from Thebesian veins or remnants of embryonic sinusoids. Exercise stress myocardial scintigraphy has a high potential to detect myocardial ischemia due to intracoronary steal. Exercise stress myocardial scintigraphy was used to demonstrate myocardial ischemia in multiple coronary arterioventricular connections. It is concluded that exercise stress myocardial scintigraphy is a reliable test to differentiate multiple coronary arterioventricular fistula from Thebesian veins or remnants of embryonic sinusoids in clinical practice.

Aged↗
PubMed1991

Sideroblastic anemia showing unique response to pyridoxine.

We treated and followed up for 6 years a patient with pyridoxine-responsive sideroblastic anemia. The patient was a boy age 1 year and 9 months, who was diagnosed on the basis of peripheral red cell morphology and an increased number of sideroblasts in the bone marrow. Bone marrow erythroblasts showed a marked reduction of delta-aminolevulinic acid synthase (ALA-S) activity. The response of the patient to pyridoxine and its active form, pyridoxal phosphate, was unique. After the first course of pyridoxal phosphate therapy (300 to 500 mg/day i.v. for 4 days), all hematological data were restored to normal and remained normal for 29 months without the further administration of pyridoxal phosphate. The second course of pyridoxal phosphate therapy (500 mg/day i.v. for 2 days) was effective for 6 months. The third, fourth, and fifth courses of the therapy consisted of daily oral pyridoxine hydrochloride at a dose of 180 mg/day for 4 to 6 weeks, and the respective periods of hematological remission were 7, 12, and greater than 18 months. These observations suggest the presence of a complicated ALA-S activating or inactivating system, or both, in our patient.

5-Aminolevulinate Synthetase↗
PubMed1991

Pharmacokinetics of pirarubicin in pediatric patients.

The pharmacokinetics of pirarubicin and its active metabolite, doxorubicin, were studied after intravenous administration of pirarubicin (25-45 mg/m2) to ten pediatric patients. The concentration-time curves of pirarubicin in both blood and plasma showed representative biphasic patterns. Pirarubicin concentrations decreased rapidly from 0.5 to 2 h after administration and then decreased slowly until 24 h in all subjects. High concentrations of the metabolite, doxorubicin, were detected at 0.5 h after administration of pirarubicin which decreased gradually until 24 h. The area under the concentration-time curve from 0 to 24 h (AUC0-24) of pirarubicin and doxorubicin in blood were 3-4 times higher than those in plasma, suggesting that these drugs had a high affinity for blood cells. The AUC0-24 ratio of doxorubicin to pirarubicin in plasma was calculated to be 0.441. It might be indicated that not only pirarubicin but also doxorubicin are responsible for the therapeutic efficacy and the incidence of toxicity of pirarubicin. The pharmacokinetics of pirarubicin in pediatric patients was fundamentally similar to that of adults, but it was recognized that considerable interindividual variation in the disposition of pirarubicin and doxorubicin exists.

Adolescent↗
PubMed1991

[Factors regulating venous return: analysis based on the respiratory variations of superior vena caval flow].

Characteristics of venous return and its determining factors were observed using pulsed Doppler echocardiography. Superior vena caval (SVC) flow was regarded as representing venous return. Ten healthy subjects and 23 patients with chronic pulmonary disease were studied. 1. In the healthy subjects, the forward flow was biphasic with dominant systolic (S) wave. Among 23 patients, 18 had normal SVC flow patterns (Group I), while in the remaining 5, SVC flow showed disappearance of the diastolic (D) wave, or both the D and S waves (Group II). 2. The healthy subjects and Group I patients had negative pleural pressures during inspiration and expiration. Consistent findings in Group II patients included positive pleural pressures during expiration and reduction in FEV1.0%. In the normal subjects and Group I patients, right atrial (RA) pressure was less than the pressure of the subclavian vein (ScV) during an entire respiratory phase. However, in Group II, RA pressure was equal to or greater than ScV pressure during expiration, resulting in disappearance or reversal of the S and D waves. 3. Respiratory variation in pleural pressure correlated significantly with that of the S wave (r = 0.77) (p < 0.005), D wave (r = 0.80) (p < 0.005), x descent of RA pressure (r = 0.77) (p < 0.005), and y descent of RA pressure (r = 0.82) (p < 0.005). The present study clearly confirmed that the superior vena caval flow patterns were closely correlated with right heart hemodynamics and truly reflected the effects of pleural pressure.

Aged↗
PubMed1991

[Venous return disturbances in chronic pulmonary disease: a study using pulsed Doppler echocardiography].

Pulsed Doppler echocardiography was used for investigation of respiratory changes of superior vena caval flow in chronic pulmonary disease to analyze the mode of venous return and its regulating factors. The subjects consisted of 55 patients with various pulmonary diseases and 44 healthy controls. 1. In the controls, the velocities of the S and D waves increased during the inspiratory phase. 2. Patients with pulmonary diseases were categorized into 2 groups. One with the mode of the healthy subjects (normal pattern), and the other with disappearance of the D wave or both the S and D waves (abnormal pattern) in the expiratory phase. All patients with restricted ventilation exhibited the normal patterns, while the abnormal patterns were observed in some of the patients with obstructive ventilation, and most of the patients with combined ventilation. 3. The respiratory patterns of the pressure gradients between the right atrium and subclavian vein reflected patterns of the superior vena caval flow well. In cases with abnormal patterns, the right atrial pressure exceeded the subclavian vein pressure in the expiratory phase. 4. The velocity of the A wave at the expiratory phase correlated significantly with pulmonary vascular resistance and with the mean pulmonary artery pressure. In conclusion, the mode of venous return in patients with pulmonary disease varies depending on the mode of the ventilation disturbance and the presence of right ventricular pressure overload, which is most likely caused by the intrathoracic pressure and by right ventricular filling abnormalities.

Aged↗
PubMed1990

[Change of renal function immediately after angiography].

Abdominal angiography using ioxaglate (3.0-4.5 ml/kg) was performed in 10 patients with normal renal function. Ccr, FENa, CH2O were compared before and immediately after angiography. There was no significant change in Ccr and CH2O level, while FENa increased remarkably after angiography. This study suggested that the osmotic diuresis and the proximal tubular stress were induced by administrated low osmolality contrast material during conventional abdominal angiography.

Aged↗
PubMed1990

Natural history of colorectal polyps and the effect of polypectomy on occurrence of subsequent cancer.

To elucidate the natural history of colorectal polyps and to observe the influence of endoscopic polypectomy on the incidence of colorectal cancer, we conducted a retrospective cohort study of all patients who had undergone colonoscopic examination at the Center for Adult Diseases, Osaka, between April 1974 and December 1985. The study subjects consisted of a control group (760 non-polyp patients) and a polyp group (648 polyp patients, including 136 treated by polypectomy at the initial examination). These subjects were followed up until the end of 1987 by record linkage with the Osaka Cancer Registry's file to observe the occurrence of colorectal cancer. The O/E (observed/expected numbers derived from the general population) was 5.1 (95% confidence interval = 2.5-9.4) and 1.0 (0.1-3.6) for the polyp and control group, respectively. When subjects in the polyp group were categorized into polypectomy and non-polypectomy sub-groups, the O/E was 2.3 (0.1-12.6) and 8.0 (3.4-15.8) respectively. The relative risk of undergoing polypectomy to developing subsequent cancer was estimated at 0.3 (0.1-2.1). These results suggest an increased risk of developing cancer among polyp patients and the possibility of prophylactic effect of polypectomy against subsequent cancer. A large-scale and long-term follow-up study is required to confirm these findings.

Age Factors↗
PubMed1990

Estimation of validity of mass screening program for gastric cancer in Osaka, Japan.

To assess the validity of mass screening tests for gastric cancer conducted with three types of radiographic techniques, i.e., photofluorography by a mirror camera, photofluorography by an image intensifier, and direct radiography, 105,122 persons who underwent a total of 272,667 screening tests during 1970 through 1982 were followed through December 31, 1983 by means of a record linkage to the Osaka Cancer Registry, Osaka, Japan. The results of 1 year's follow-up from screening were defined as the gold standard and test performance values were calculated. Sensitivity of screening with photofluorography by a mirror camera, photofluorography by an image intensifier, and direct radiography was 90%, 89%, and 91%, and specificity was 86%, 92%, and 91%, respectively. The receiver operating characteristics curve for screening with photofluorography by an image intensifier resembled that for direct radiography and these two curves were located somewhat to the left of the curve for screening with photofluorography by a mirror camera. The authors conclude that the validity of screening with photofluorography by an image intensifier is almost equivalent to that of screening with direct radiography and both are superior to that of screening with photofluorography by a mirror camera.

Adult↗
PubMed1990

Superior vena cava syndrome as a complication of DDD pacemaker implantation.

A 75-year-old man was admitted to our hospital because of swelling of the face and neck 6 months after implantation of a two-chamber pacemaker. Digital subtraction angiography showed total occlusion of the superior vena cava vein and well-developed collateral channels. After thrombolytic therapy, facial swelling disappeared. Digital subtraction angiography performed after thrombolytic therapy revealed a recanalization of the superior vena cava.

Aged↗
PubMed1990

Sites of action of soltriol (vitamin D) in hamster spleen, thymus, and lymph node, studied by autoradiography.

Siberian hamsters (Photopus sungorus) were injected with 3H dihydroxycholecalciferol (vitamin D, soltriol). Autoradiograms of spleen, thymus, and lymph nodes revealed nuclear concentration of the hormone in a select population of cells in all of these organs. In the spleen, labeled cells were abundant in the red pulp, but sparse in the white pulp. In the periarterial lymphatic sheath (PALS) labeled cells were found predominantly at the outer rim, with a few scattered labeled cells in the inner PALS and in the marginal zone. Lymphocytes, including pyronin-positive plasma cells, did not display nuclear labeling. In the red pulp, some of the labeled cells contained pigmented inclusions in the cytoplasm, while most of the labeled cells did not appear phagocytic under the conditions of the experiment. In the thymus, labeled cells were most numerous in the medulla, but sparse in the cortex. Many of the thymic target cells were larger than the unlabeled lymphocytes, with a large and pale nucleus, sometimes containing a distinct nucleous, and with large and dendritic cytoplasm, having the appearance and distribution of epithelio-reticular cells. In lymph nodes, scattered labeled cells were conspicuous in or near the subcapsular sinus, while other cells did not concentrate radioactivity in their nuclei. The results indicate that nuclear receptors and direct genomic actions for soltriol exist in certain cell populations of lymphatic tissues that probably include reticular cells and a subpopulation of macrophages. These target cells may mediate effects of the steroid on lymphocytes that appear to have no or only very low numbers of nuclear receptors.

Animals↗
PubMed1990

Distribution of progestin-binding cells in estrogen-treated and untreated neonatal mouse uterus and oviduct: autoradiographic study with [125I]progestin.

Progestin-binding sites in uteri and oviducts of estrogen-treated and untreated 8-day-old mice were studied by thaw-mount autoradiography with [125I]progestin. In the untreated uteri, nuclear concentration of radiolabelled progestin was observed in all tissues of the uterus, with strongest nuclear labelling in luminal and glandular epithelia and in stroma. In the estrogen-treated uteri, the degree of labelling was markedly augmented in stroma and muscle, but much reduced in the luminal and glandular epithelia, compared to untreated uteri. In untreated oviducts, nuclear labelling was observed in stroma and muscle in all regions and in epithelium in the isthmic and uterine regions. The epithelium in infundibular and ampullar regions was only scarcely labelled. The estrogen-treatment augmented the labelling in stroma and muscle of the oviduct as in the uterus, but the labelling in epithelium was not affected. These results indicate that estrogen-treatment induces progesterone receptor differentially among tissue compartments both in the uterus and oviduct.

Animals↗
PubMed1990

Serum carnitine and nutritional status in children treated with continuous ambulatory peritoneal dialysis.

The serum carnitine (total carnitine), total protein, amino acid, and triglyceride levels were determined in children on continuous ambulatory peritoneal dialysis (CAPD). Compared with levels in controls, serum carnitine levels were significantly decreased in patients on CAPD for more than 4 months, while those of patients on CAPD for 1-3 months were not decreased. Patients on CAPD for more than 4 months also showed lower serum total protein levels than in normal controls. The mean triglyceride levels in patients on CAPD for both 1-3 months and more than 4 months were higher than those in normal controls. Among the amino acids, the serum levels of tryptophan, isoleucine, leucine, tyrosine, valine, serine, and asparagine were significantly lower in patients treated with CAPD than in normal controls, whereas the levels of other amino acids were either increased or not changed. Isoleucine and leucine levels showed a strong correlation with serum carnitine. Our data suggest that malnutrition plays a role in the decrease of serum carnitine levels in patients receiving CAPD.

Amino Acids↗
PubMed1990

Close correlation between the distribution of tenascin and that of actin filaments in the mouse urethral mesenchyme during active morphogenesis.

The distribution of tenascin, an extracellular matrix glycoprotein, and that of actin filaments were studied in the developing urethra of mouse embryos by antitenascin immunofluorescent and rhodamine-phalloidin staining. Tenascin appeared transiently in the urethral mesenchyme at the site of active morphogenesis in which the urethral epithelium separated from the surface epithelia of the glans and prepuce, being tubular, and the bilateral mesenchymes lining the preexisting urethral epithelium were seamed together in the ventral side of the tubular urethra immediately after the epithelial separation. The spatially and temporally restricted distribution of tenascin corresponded well to that of mesenchymal cells which possessed many actin filaments. These observations suggest that tenascin is involved in the cytoskeletal organization of mesenchymal cells in the active phase of morphogenesis.

Actins↗