Search PubMed⌕ Search

Biomedical subjects

S Sakamoto

Publications and source records attributed to S Sakamoto.

At least 739 records · Page 41Linked to original sources
PubMed1983

Effects of nitrous oxide on human cell lines.

Hematopoietic and nonhematopoietic cell lines cultured in media containing either 5-methyltetrahydrofolate or 5-formyltetrahydrofolate grow well to the same extent. However, when these same cell lines are grown in the presence of nitrous oxide, selective growth inhibition can be shown for hematopoietic cells cultured in 5-methyltetrahydrofolate-containing media. These cells also demonstrated a decreased ability to suppress [3H]-thymidine incorporation into DNA in deoxyuridine suppression tests.

B-Lymphocytes↗
PubMed1983

[Functional tricuspid regurgitation and its relation to the morphology of the tricuspid valve and annulus: pulsed doppler echocardiography and two-dimensional echocardiography].

The mechanism for the development of functional tricuspid regurgitation (TR) was studied by an ultrasonic method. Thirty-five examinations were performed in 31 patients who were expected to have functional TR, and the severity was classified into 4 grades according to the extension of the regurgitant signals by pulsed Doppler echocardiography. The satisfactory horizontal section of the tricuspid valve was obtained by two-dimensional echocardiography (2DE) to measure the tricuspid annular diameter and to observe systolic configuration of the tricuspid valve in 22 examinations. The tricuspid annular diameter was well correlated with the severity of TR, and "lack of coaptation" of the valve was recognized on 2DE in some cases of severe TR with the markedly dilated annulus, indicating that this dilatation was an important trigger of functional TR. Additionally, in the majority of patients with severe TR, "anterior displacement" of the tips of tricuspid leaflet(s) (6 mm or more from the tricuspid annulus towards the right ventricle) was observed, which was thought to be due to the chordal traction secondary to the right ventricular dilatation, and contributed to the development of functional TR by disturbing sufficient coaptation. In one particular case, severe TR was associated with " malaligned coaptation" caused by the anterior displacement confined to the septal leaflet, indicating that asymmetrical dilatation of the right ventricle and/or disorientation of chordae-valve system may contribute to TR.(ABSTRACT TRUNCATED AT 250 WORDS)

Dilatation, Pathologic↗
PubMed1983

[An application of X-ray computed tomography for complex cardiac anomalies].

X-ray computed tomography (CT) was performed in two patients with complex congenital heart disease in order to assess the clinical utility in the systemic morphological diagnosis. A Somotom 2 whole body CT scanner (Siemens Co) was used, and contrast enhanced CT scanning and a dynamic CT scanning were performed in one case (Case 2).; Case 1: A 20-year-old female with double outlet right ventricle (S, D, L), pulmonary stenosis and aortic insufficiency. The CT revealed a viscero-atrial situs, ventriculoarterial relation, spatial interrelationship between the great arteries and a run of the stenotic pulmonary artery. The CT clarified spatial relationship among four cardiac chambers, ventricular septal defect and great arteries, contributing to the understanding of the complex cardiac structure. Case 2: A 26-year-old female with single ventricle (III-C solitus), pulmonary stenosis, dextroversion, left superior vena cava and WPW syndrome. The CT documented precisely a viscero-atrial situs, dextroversion, ventriculoarterial relation, spatial interrelationship between the great arteries, stenotic main and left pulmonary arteries and a dilated right pulmonary artery due to the right Blalock-Taussig operation performed 15 years before. A diagnosis of left superior vena cava could be made by CT, and its flow into coronary sinus was visualized by dynamic CT. The dynamic CT also clarified a mixing of venous and arterial blood in the common ventricle, and revealed a rudimentary ventricular septum. Thus, the CT serves useful purposes especially as examination of viscero-atrial situs, ventriculoarterial relation and spatial interrelationship between great arteries, and anomalies of the mediastinal vessels. Furthermore the relationship among four cardiac chambers, ventricular septal defect, and the pattern of blood flow were also clarified. However, the CT failed to define the state of a ventricular loop, because it could not identify ventricular muscular structures and atrioventricular valves as these move rather vigorously. The CT could not locate pulmonary stenosis, valvular or somewhere else. The CT seemed to be a promising noninvasive method in the systemic morphological diagnosis of congenital heart disease as subsidiary to echocardiographic investigation. However, in pediatric patients, it seemed considerably hard to obtain clear cardiac CT images because of the difficulty in halting respiration during procedure.

Adult↗
PubMed1982

Application of a galactosylceramidase microassay method to early prenatal diagnosis of Krabbe's disease.

An enzymatic microassay method was devised to determine galactosylceramidase activities of microsamples prepared from primary cultures of amniotic fluid cells. A piece of freeze-dried cell mass (0.5--1 microgram dry weight) prepared from a colony on the bottom plate of a culture flask, was weighed and incubated in 4.02 microliter of the assay mixture. A small amount of galactose hydrolyzed from galactosylceramide was amplified about 10 000-fold and determined by using an enzymatic amplification reaction, NAD cycling. Microsamples were also prepared from freeze-dried leukocytes and skin fibroblasts. The present method was applied to prenatal diagnosis using amniotic cells as a sample in a case of high-risk pregnancy for Krabbe's disease. The result was confirmed by analysis of fibroblasts and organs from the aborted fetus.

Amniotic Fluid↗
PubMed1982

[Studies on steroidogenesis in the oocyte].

The steroid hormone has an important role in the early stages of reproduction. There has been abundant histochemical evidence that oocytes contain steroid hormones and are able to synthesize these hormones. But there have been few methods of analyzing one oocyte biochemically because it is too small and light. In order to study steroidogenesis in the oocyte, a microassay method sensitive enough to analyze the enzyme activities in one oocyte was developed using enzymatic cyling for amplifying the reaction product to 10,000-fold. An oil-well technique and a microtube method were applied in the assay for achieving the reaction in a medium as small as 1.0 to 5.0 microliters under a stereomicroscope. Immature Wistar rats were superovulated by PMS-hCG administration. Oocytes were collected by puncturing the follicle and flushing the tube. They were freeze-dried after washing to remove cumulus cells. The dry weight of one oocyte was 51.2 +/- 6.2 ng in a quartz fiber fishpole balance. The activity of 3 beta hydroxysteroid dehydrogenase (3 beta HSD) (picomol/oocyte/hr, substrate:pregnenolone) in the PMS-treated oocyte was 2.66 +/- 0.59, which corresponds to 3 times the activity of the ovarian homogenate as control, indicating the high capacity of oocytes to produce progesterone. The activity increased significantly (P less than 0.01) by hCG administration up to 4.17 +/- 0.29 after ovulation, suggesting that gonadotropin regulates steroidogenesis in the oocyte. The activities of G6PD and 6PGD were 8.41 +/- 1.09 picomol/oocyte/min and 3.85 +/- 2.02 picomol/oocyte/hr, respectively. The high activity of G6PD (more than 10 times that of the ovarian homogenate) suggests that the pentose phosphate shunt concerned with steroidogenesis is active in the oocyte. HCG decreased the activities of both G6PD and 6PGD. The present results show that steroidogenesis in the oocyte is very active under the control of gonadotropin, suggesting that steroid hormones may play an important role in oocyte maturation, ovulation and fertilization.

3-Hydroxysteroid Dehydrogenases↗
PubMed1982

[Estrogen receptors of the rat uterus during pregnancy and lactation].

Uterine estrogen receptors (ER) of the rat during pregnancy and postpartal lactation were assayed. Both the cytoplasmic and nuclear ER were determined by the controlled pore glass (CPG) method as previously described in detail. The cytoplasmic ER level slightly decreased as pregnancy advanced and then increased remarkably during postpartal lactation, with a tendency to decrease at 5 weeks of lactation when the estrous cycle could have recurred despite the nursing behavior of the rats. On the other hand, no remarkable difference in nuclear ER was noted during pregnancy and lactation. A high concentration of plasma progesterone could have reduced the translocation of the cytoplasmic ER to the nucleus and the replenishment of the cytoplasmic ER, despite a high concentration of plasma estrogen during pregnancy. In order to keep an environment of a high plasma concentration of estrogen similar to that of pregnancy, a long-acting estrogen (estradiol dipropionate) was injected in to the proestrous rats. The cytoplasmic ER rapidly translocated to the nucleus, followed by a prolonged maintenance of a low cytoplasmic and a high nuclear ER level until 7 days, with a gradual replenishment of the cytoplasmic Er and a gradual decline of the nuclear ER thereafter. A translocation of the cytoplasmic Er to the nucleus, similarly seen in the hysterectonized-adult rats treated with estradiol, was noted in the rats injected with estradiol at 3 weeks of lactation. In general, low estrogen and high prolactin may be held in plasma during lactation. These results indicate that the fluctuation of uterine ER simply depends on the plasma level of estrogen during pregnancy and postpartal lactation in rats.

Animals↗