Biomedical subjects

R Yamada

Publications and source records attributed to R Yamada.

At least 163 records · Page 9Linked to original sources

PubMed1993

Local regulatory effects of activin A and follistatin on meiotic maturation of rat oocytes.

Activin A and follistatin identified in follicular fluids have been shown to regulate follicular development. Activin A, in a dose responsive manner, increased the percentage of germinal vesicle breakdown that served as a marker for the resumption of meiosis of oocytes in vitro, especially these obtained from immature follicles. This effect of activin A was inhibited by the activin-binding protein, follistatin. Follistatin alone exerted an inhibitory effect on oocyte maturation. Reverse transcription and polymerase chain reaction revealed the expression of activin beta A and activin type IIA receptor gene transcripts in the oocytes. Activin A, along with follistatin, appears to play a local regulatory role in the meiotic maturation of rat oocytes.

Activin Receptors↗

PubMed1993

Prenatal diagnosis and treatment strategy for congenital mesoblastic nephroma.

By means of the recent sophisticated technology regarding prenatal diagnosis, congenital mesoblastic nephroma (CMN) has become detectable before birth, or at a younger age than previously. Recently we treated an infant with a huge CMN in whom fetal asphyxia and tumor rupture occurred during the perinatal observation period after prenatal detection. Emergency surgery was required, and the postoperative course was complicated. The treatment strategy of the perinatal care team should focus on (1) reliable maternal transportation (2) continuous monitoring of fetal condition including cardiovascular status, (3) control of polyhydramnios to avoid premature labor, and (4) elective surgery at a stable or stabilized condition. Emergency surgery should be performed when circulatory disturbance, respiratory distress, and/or impending rupture are suspected.

Adult↗

PubMed1993

Gender dependence of D-aspartate oxidase activity in rat tissues.

1. A gender difference in D-aspartate oxidase activity was demonstrated for the first time in rat tissues. 2. In adult Wistar rats, the hepatic enzyme activity was constantly higher in females than males. The renal activity showed a similar tendency. 3. The gender difference in the hepatic activity was not observed in newborn animals, but became apparent with growth almost in parallel with sexual maturation. 4. The hepatic activity in females was greatly affected by pregnancy and parturition.

Aging↗

PubMed1993

Diagnosis and treatment of proximal tubal obstruction by fluoroscopic transcervical fallopian tube catheterization.

The efficacy of fluoroscopic transcervical Fallopian tube catheterization in treating patients with proximal tubal obstruction was investigated. In 11 (15.9%) of the 69 patients who entered the study, patency of the proximal Fallopian tubes was shown by a pre-treatment hysterosalpingogram or an ostial selective salpingogram. Transcervical Fallopian tube catheterization attested to the success of recanalization in at least one of the obstructed tubes in 41 of our 58 patients (70.7%). Of 92 obstructed tubes, 56 (60.9%) were successfully recanalized. However, normal tubal visualization was possible in only 13 tubes (23.2%). Most of the recanalized tubes were considered to be peritubal adhesions (64.3%). Eight of 36 (22.2%) patients who had been successfully recanalized achieved pregnancies; 12 patients demonstrated normally appearing salpingograms after the procedure, and five (41.7%) had an intra-uterine pregnancy. Suspected peritubal adhesions were exhibited on post-operative salpingograms of 24 patients, one of whom had an intra-uterine pregnancy, while two had tubal pregnancies. Transcervical Fallopian tube catheterization is a simple and effective method for evaluating and treating proximal tubal obstruction. Most of the patients (70.7%) in whom recanalization was successful showed significant signs of distal tubal damage. This procedure can also be used to arrive at a prognosis regarding conception.

Adult↗

PubMed1993

Distribution and effect of iodized poppyseed oil in the liver after hepatic artery embolization: experimental study in several animal species.

To define the intrahepatic distribution of iodized poppyseed oil and its effect on the liver, hepatic artery embolization (HAE) was performed in five mice, 12 rats, four rabbits, and 21 pigs with the iodized oil alone or in combination with gelatin sponge powder (GSPow) in three rats or gelatin sponge particles (GSPs) in nine pigs. All mice, rats, and rabbits underwent radiography of the upper abdomen and in vivo microscopy of the hepatic periphery during and immediately after injection and 1, 4, and 24 hours later. All pigs underwent angiography before and after HAE as well as measurement of portal venous pressure before HAE and 15, 30, 45, and 60 minutes and 4 weeks after HAE. Follow-up radiographs were obtained in 18 pigs. HAE performed with the iodized oil only was well tolerated by the liver, even when high doses were used, likely because of continuous flushing of the sinusoids by high blood flow from peripheral arterioles. When HAE was performed with the iodized oil and GSPow, this blood flow ceased and necrosis developed. The degree of necrosis after HAE with the iodized oil in combination with GSPs was directly associated with the dose of iodized oil. HAE performed with GSPs only did not cause damage.

Animals↗

PubMed1993

Self-expandable metallic stent therapy for superior vena cava syndrome: clinical observations.

PURPOSE: To study clinical and physiologic aspects of Z-stent therapy for superior vena cava (SVC) syndrome secondary to malignant disease. MATERIALS AND METHODS: Signs and symptoms of SVC syndrome were classified, graded, and scored in 11 cases. Six patients with caval pressure higher than 22 mm Hg peripheral to the stenosis underwent stent therapy. RESULTS: Immediately after Z-stent implantation into the stenotic lesion, the diameter of the constriction increased from 3.3 mm +/- 2.0 (mean +/- standard deviation) to 14.0 mm +/- 3.2, the mean caval pressure peripheral to the stenosis decreased from 26.6 mm Hg +/- 2.5 to 8.9 mm Hg +/- 0.7, and the symptom score decreased from 6.7 +/- 1.8 to 1.3 +/- 1.4. The caval pressure, lesion diameter, and symptom score correlated highly with each other. One complication--transient pulmonary edema attributable to volume overload caused by reperfusion--was observed. Mean survival exceeded 7.1 months. CONCLUSION: Stent placement could be a useful treatment for refractory SVC syndrome.

Aged↗

PubMed1993

Splenic gonadal fusion with persistent müllerian duct syndrome.

Splenic gonadal fusion is a rare anomaly that is frequently associated with skeletal abnormalities or occasionally with cryptorchism. But the case of this anomaly accompanied by male pseudohermaphroditism here represents, to our knowledge, the first report of splenic gonadal fusion with persistent müllerian duct syndrome.

Abnormalities, Multiple↗

PubMed1993

Expression of follistatin, an activin-binding protein, in vascular smooth muscle cells and arteriosclerotic lesions.

Activin-A has a mitogenic effect on vascular smooth muscle cells (SMCs) and is produced by monocyte/macrophage lineage cells. Here, we studied the expression of follistatin, an activin-binding protein, in both A10 cells, a rat aortic SMC line, and vascular SMCs derived from adult rat aorta. Follistatin mRNA was detected in these cells by Northern blot analysis. Ligand blot and immunoblot analyses demonstrated that follistatin was produced in the conditioned medium at a higher level by A10 cells than by SMCs. Furthermore, immunostaining and in situ hybridization of the arteriosclerotic lesions showed that follistatin was highly expressed in the diseased artery, where abnormal proliferation of SMCs occurred. We suggest that follistatin is produced by vascular SMCs and is involved in the course of atherogenesis.

Activins↗

PubMed1993

[A survey of primary lung cancer among NTT workers in the Tokyo area. The incidence and mortality during the past 30 years and significance of radiologic screening].

An epidemiological study of primary lung cancer was conducted on NTT workers in the Tokyo area (about 40,000 persons). During the past 30 years (1960-1989), 77 cases (71 males and 6 females) of primary lung cancer were detected by routine medical examination (radiologic screening by radiophotography at their workplaces) or by clinical symptoms, of whom 59 (54 males and 5 females) were dead as of the end of December 1991. Standardized incidence rate and standardized death rate of the males by the direct method (5-yr age groups from 20 to 59 yr of age, per 100,000 population) were 4.5 in the 1960's, 9.9 in the 1970's and 9.8 in the 1980's, and 3.3 in the 1960's, 7.9 in the 1970's and 8.2 in the 1980's, respectively, with increase being observed from the 1970's. Standardized incidence ratio and standardized death ratio of the males by the indirect method (5-yr age groups from 20 to 59 yr of age) were 107 in the 1970's, 86.8 in the 1980's, and 53.8 in the 1960's, 99.4 in the 1970's and 98.5 in the 1980's, respectively. No significant difference could be observed when compared to the national average. By histological type, 44 cases of adenocarcinoma, 12 cases of squamous cell carcinoma, 8 cases of small cell carcinoma, 7 cases of large cell carcinoma and 6 cases of other or unclear types were detected. Excluding the 3 unclear cases, of the 77 cases, 54 cases were peripheral type and the remaining 20 cases were hilar type on radiophotography. Peripheral adenocarcinoma was the most common type.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1993

[Results of initial bacteriology of pulmonary tuberculosis among male NTT employees in the Tokyo area--annual transition and influence of fiberoptic bronchoscopy].

A study was made on the annual changes in the positive rate for acid-fast bacilli (AFB) at the initial bacteriological examination of newly detected pulmonary tuberculosis among male NTT (Nippon Telegraph and Telephone Corporation) employees in the Tokyo area during a period of 32 years from 1960 through 1991. The influence on the changes of recent introduction of fiberoptic bronchoscopy for obtaining the specimen was also analyzed, and the following results were obtained. 1. Results obtained by the conventional bacteriological method using expectorated sputum or aspirated gastric juice as the specimens. (1) The annual incidence of bacteriologically positive (smear and/or culture positive) cases constantly decreased and reached the lowest in 1981, then ceased to decline and remained at the level of 1981. (2) The annual ratio of AFB positive by smear and the ratio of smear and/or culture positive cases to the newly detected cases of pulmonary tuberculosis were constant during the entire observation period. (3) The ratio of AFB positive by smear to the newly detected cases annually increased but did not increase when the observation period was limited to within 1976 to 1991. 2. Results obtained by fiberoptic bronchoscopy in combination with conventional bacteriological methods. (1) Both the annual incidence of smear and/or culture positive cases and the ratio of these cases to the newly detected cases of pulmonary tuberculosis showed a tendency to increase in both the 80's and 90's.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1993

[Evaluation of tissue plasminogen activator and plasminogen activator inhibitor-1 in blood obtained from patients of idiopathic central serous chorioretinopathy].

It is postulated that idiopathic central serous chorioretinopathy (ICSC) may be induced by a variety of underlying choroidal diseases capable of producing initially alterations in the permeability of the choriocapillaries. A history of unusual emotional stress frequently accompanies the onset of visual complaints. We have reported that alterations of serum lipids may exert a powerful effect on tissue plasminogen activator (t-PA) levels acting as a risk factor of variable cardioangiopathies. In this study, we evaluated the levels of t-PA activity, t-PA antigen and plasminogen activator inhibitor-1 (PAI-1) in blood from the patients with central serous chorioretinopathy, and compared them with the levels of total cholesterols (TCH), triglycerides (TG), and high-density lipoprotein cholesterol (HDL). t-PA activity levels and HDL were lower than in standard controls but t-PA antigen, PAI-1 antigen, and TG were higher. These facts may be associated with the pathogenesis or pathophysiological features of ICSC.

Adult↗

PubMed1993

Dacron-covered stent therapy for portal vein tumor thrombus in hepatocellular carcinoma.

A tumor thrombus of the portal vein is refractory to therapy and constitutes a serious prognostic factor in hepatocellular carcinoma. For the purpose of treating portal vein tumor thrombus by restoring the blood flow and preventing recurrent ingrowth of tumor, we devised a metallic stent partially covered with a Dacron mesh sheet, and a coaxial percutaneous delivery system. One half of the wall of a Gianturco Z-stent was covered with a sheet of 0.25-mm-thick Dacron mesh, fixed to the stent wall with nylon threads. The covered stent was implanted in a patient with severe main portal vein stenosis due to tumor thrombus protruding from the left portal vein branch. Immediately after stent placement the tumor stenosis was effectively dilated, the portal blood flow restored, and the portal hypertension relieved. CT and angiography after 8 months still showed complete portal vein patency. Intrahepatic tumor dissemination or other complications were not observed. Intraportal placement of a covered metallic stent appears to be an efficacious therapy of major portal tumor thrombi.

Carcinoma, Hepatocellular↗

PubMed1993

[Incidence of pulmonary tuberculosis among workers of NTT in Tokyo area--annual transition by sex and age].

We investigated incidence of pulmonary tuberculosis for 31 years (from 1960 to 1990) by sex and age among workers of NTT (Nippon telegraph and telephone corporation) in Tokyo area. Annual transition of recent years was mainly analyzed and following results were obtained. (1) Incidence in male of the twenties, thirties and forties decreased smoothly from 1960 to around 1980, then came to standstill and increase tendency was suspected, that is to say, 1) incidence in male of the twenties was minimum in 1976 (21 per 100,000 persons). Annual reduction rate (minus means decrease, plus means increase) from 1960 to 1976 was -11.7% and that from 1977 to 1990 was -0.4%. 2) incidence in male of the thirties was minimum in 1983 (0 per 100,000 persons). Annual reduction rate from 1960 to 1982 was -8.8% and that from 1984 to 1990 was +6.8%. 3) incidence in male of the forties was minimum in 1981 (0 per 100,000 persons). Annual reduction rate from 1960 to 1980 was -11.5% and that from 1982 to 1990 was +1.3%. (2) Incidence in male of the fifties decreased gradually from the 1960's and no tendency of increase was observed. (3) Incidence in female of the twenties, thirties and forties decreased almost continuously from 1960 to 1990 and no tendency of increase was observed in each age group, but total incidence in female (from the teens to the sixties) seemed to be leveling off after 1979. From these results, stagnant or increase tendency of pulmonary tuberculosis in young and middle-aged male was noticed.

Adult↗

PubMed1992

[Expandable metallic stent therapy for SVC syndrome--effects on local venous pressure, vascular diameter, symptoms, and these correlations].

To evaluate the efficacy of Z-stent therapy for SVC syndrome, we studied changes in the pressure, the diameter of stenotic lumen and the symptoms in the cases of SVC syndrome with higher pressure than 30 cmH2O at distal to the stenosis. The symptoms were classified and graded to be scored up. Immediately after the Z-stent placement into the stenotic lesions, the venous pressure distal to the stenosis decreased from 36.0 +/- 3.4 cmH2O to 12.0 +/- 12.0 cmH2O (p < 0.001), the diameter of stenotic lumen increased from 3.3 +/- 3.4 mm to 14.0 +/- 3.4 mm (p < 0.01). According to the remarkable symptomatic improvements the averaged score decreased from 6.7 to 1.3 (p < 0.01). The pressure, the diameter and the symptom scores were highly correlated each other (magnitude of gamma not equal to 0.9). Among two cases with the right atrial pressure increase by 2 cmH2O after the placement one suffered transient cardiac in compensation due to overload by reperfusion. Conclusively, the Z-stent therapy was very effective on the SVC syndrome in reducing abnormally elevated venous pressure due to the stenosis, and relieving the symptoms, while the pressure monitor was necessary.

Aged↗

PubMed1992

[Transjugular intrahepatic portosystemic shunt: a case report].

Transjugular intrahepatic portosystemic shunt (TIPS) was performed in one patient with refractory esophageal varices due to portal hypertension by liver cirrhosis. Rösch modified Z-stent was placed to keep the lumen. The shunt lowered average portal pressure from 45 to 24 mmHg, and then decompressed the esophageal varices. The shunt was patent still for three months after the creation. No significant complication was observed. This initial success of TIPS in Japan encouragingly support the safeness and effectiveness of this therapy.

Esophageal and Gastric Varices↗

PubMed1992

Induction of differentiation of the human promyelocytic cell line HL-60 by activin/EDF.

A human promyelocytic cell line, HL-60, treated with activin/EDF was found to differentiate into monocyte/macrophage-like cells. This was shown not only by morphology but by the loss of myeloperoxidase granules and the appearance of nonspecific esterase. Dose-dependent inhibition of the differentiation by follistatin, an activin-binding protein, confirmed that it was indeed caused by activin. Thus, activin/EDF exerts its effect on hematopoietic cells not only on erythroid differentiation but also on at least a part of myeloid cell differentiation.

Activins↗

PubMed1992

[A stent therapy for portal tumor thrombi. Use of Dacron sheet covered self expandable metallic stent].

We developed a method of intraportal placement of a covered stent against portal tumor thrombi. Half around a z-stent was covered with a Dacron mesh sheet. In one case with portal tumor thrombi protruding into the main portal branch, the stent was placed percutaneously-transhepatically, through a coaxial introducer. Immediately after the placement, portal vein was dilated and, which was still patent after six months. No complication has been observed.

Carcinoma, Hepatocellular↗

PubMed1992

Follistatin is a developmentally regulated cytokine in neural differentiation.

Activin acts mitogenically on P19 cells as well as being inhibitory of the differentiation of retinoic acid-treated P19 cells and some neuroblastoma cell lines. Here, we show some lines of evidence that follistatin, an activin-binding protein, is also involved in neural differentiation. Counteracting the activity of activin, addition of follistatin suppresses the anchorage-independent growth of P19 cells in soft agar and stimulates neurite outgrowth of a neuroblastoma cell line, IMR-32 cells. While activin does not seem to be expressed significantly, follistatin is demonstrated in the conditioned medium of these cells. Furthermore, the expression of follistatin in P19 cells is subject to dynamic fluctuations in response to retinoic acid treatment. These neural cells may produce follistatin in a cell stage-specific manner in order to interact with exogenously derived activin.

Activin Receptors↗