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Biomedical subjects

Y Ueda

Publications and source records attributed to Y Ueda.

At least 829 records · Page 46Linked to original sources
PubMed1989

Ultrastructural evidence that the negative feedback mechanism of the pituitary-thyroid axis can operate without the hypothalamus in fetal rats: observation of thyroid follicular cells.

Hypothalamus-independent negative feedback mechanism of the pituitary-thyroid axis was studied by electron microscopic observation of thyroid follicular cells of encephalectomized or hypophysectomized fetal rats under hypothyroidism induced by propylthiouracil (PTU). Fetal hypophysectomy or encephalectomy was performed on day 19 of gestation. Mother rats were given either a daily amount of 40 mg PTU or saline alone on the day of operation and on the next day. On day 21, their fetuses were obtained. As a result, PTU induced marked goiters even in encephalectomized fetuses, the goiters being comparable in weight to those induced in littermate intact fetuses. Electron microscopically, the follicular lumen was narrowed, microvilli were lengthened with a marked increase in number, and rER was extremely expanded. Follicular cells often confined colloid droplets and lysosomes. Fetal hypophysectomy, even in PTU-treatment, caused a reduction in the thyroid weight, accompanied by flattening of follicular cells, shortening of microvilli, widening of follicular lumen, and shrinkage of rER. These findings would support the view that the negative feedback mechanism of the pituitary-thyroid axis can operate without the hypothalamus in fetal rats.

Animals↗
PubMed1989

Relationship between the development of the gubernaculum and the testicular descent in the rat fetus: macroscopic and light and electron microscopic observation.

The gubernaculum consists of the gubernacular cord connected with the vas deferens and the gubernacular bulb connected with the retroabdominal wall. The cord was first distinguished on day 15 of gestation. Its length reached the peak on day 16, followed by a reduction until day 18 to be almost constant thereafter. The bulb was first distinguished on day 16, and its length was steadily increased toward term. The testis began to descend with a reduced length of the cord. By day 19, the testis descended close to the caudal part of the bulb by the sharp bending of the cord. Microscopically, the bulb consisted at first of a centrally located mesenchymal mass and of a covering layer of myoblasts. Thereafter, the mesenchymal mass was gradually shifted toward the cranial part of the bulb, trailing loose mesenchymal tissue in the caudal part of the bulb. On day 19, the mass was decreased in cell population but increased in amount of collagen fibers. It is suggested that the testicular descent starts on day 16 together with the commencement of shortening of the gubernacular cord and enlargement of the gubernacular bulb.

Animals↗
PubMed1989

Renal transplantation in baboons under FK 506.

FK 506 was tested in unrelated baboons submitted to renal transplantation and bilateral native nephrectomy. Untreated baboons died after 9.2 +/- 4.0 SD days. When FK 506 was given orally for 90 days, survival with the optimum dose was 74.6 +/- 28.9 days; this allowed maximum credit for each individual animal of 90 days. A 3-day course of intramuscular FK 506 started on postoperative day 4 allowed 1- to 2-month survival. Delayed rejection in these baboons as well as in those treated daily for 90 days with FK could sometimes be reversed temporarily with a second 3-day course. The doses required for a good therapeutic effect were 10 times greater in baboons than in dogs, a finding that may reflect a species difference of lymphocyte sensitivity to this drug. FK appeared to be relatively nontoxic in subhuman primates, and it remains a promising drug for clinical trial.

Animals↗
PubMed1989

[Transplantable osteosarcomas in rats. I. The growth behavior of spontaneous and 4-HAQO induced osteosarcomas in rats].

While there are a number of experimental animal models for osteosarcoma development, the available rat systems are limited both in number and applicability. The present report concerns our attempts to establish an appropriate rat model to allow development of new experimental approaches to human osteosarcoma. A spontaneously occurring osteosarcoma (J. H. 1-OS) was found in a 35 week old male rat. The tumor could be transplanted and grew well and although the bone forming activity decreased after the 18th generation, the growth potential remained high.

4-Hydroxyaminoquinoline-1-oxide↗
PubMed1989

[The effect of the elastase on aminonucleoside nephrosis].

In this paper, we studied the effect of elastase on aminonucleoside (AN) nephrosis which is considered a model of focal glomerular sclerosis (FGS). Elastase is an enzyme which disintegrates elastin, discovered by Balo, and used in the treatment of arteriosclerosis and hyperlipidemia. It has also been known to improve metabolism of acid mucopolysaccharides, so, this study focused on metabolic improvement. Three groups of male Sprague-Dawley rats were studied and observed at regular intervals; 30, 60, 90 days. The ANE group (AN + elastase) was administered one shot of AN (10 mg/100 g B.W.) during the test interval, while elastase (5 mg/kg B.W.) was injected 5 days/week for the entire test interval. The AN group was administered one shot of AN only. The third group was a control (C). The following results were observed: (1) Focal segmental hyalinosis and sclerosis (FSHS); ANE group was weaker than AN group. (2) Other significant qualifying glomerular changes (vacuolar change and hyaline droplets of the epithelial cells, adhesion, and foam cells); ANE group was weaker than AN group. (3) Anion loss in GBM was shown by a lack of colloidal iron staining under light microscopy, and by a lack of PEI particles under electron microscopy; there was significantly less anion loss with ANE group, than with AN group. The findings suggest that elastase has an affect on the metabolism of acid mucopolysaccharide and collagen in sclerotic lesion, and may restrain the progress of amino-nucleoside nephrosis.

Animals↗
PubMed1989

[Coronary artery spasm under thoracic epidural anesthesia].

Three paroxysmal episodes of ST-segment elevation in lead II of ECG were observed during bullectomy and chest closing under epidural anesthesia supplemented with enflurane in compressed air in a patient who had history of variant angina with 50% obstruction of right coronary artery. The first and the third episodes were followed by ventricular tachycardia, complete A-V block and hypotension. These attacks were preceded by decreases in heart rate and blood pressure. It was suspected that coronary artery spasm developed with increased vagal tone under thoracic epidural block. The first and the second attacks were successfully treated with intravenous injection of nitroglycerin and lidocaine. The third attack needed additional treatments which included intravenous administrations of atropine, epinephrine, isoproterenol and phenylephrine and direct heart massage through the thoracic incision. Postoperative serial examinations of ECG showed inverted T in lead V1-V4, and serum enzymes (GOT, GPT, LDH, CPK, CPK-MB) were elevated. However ratio of CPK-MB to total CPK was only 1.5%. The patient was discharged two weeks after the operation with normal ECG and serum enzymes. It is speculated that coronary artery spasm was induced by hypotension and vagal stimulation under epidural anesthesia which blocks cardiac sympathetic nerves.

Aged↗
PubMed1989

[Pathomorphological studies on arterial cushion. 2. Aminonucleoside nephrotic rat].

The present study is an attempt to solve the problem of pathogenesis of focal glomerular sclerosis (FGS), especially in juxtamedullary cortex, we were investigated by measurement of luminal diameters of afferent arterioles (Aff), efferent arterioles (Eff) of numerous glomeruli, arterial cushion (AC), afferent arterioles (AC-aff) at a region of branching arteries from the interlobular arteries, using scanning electron micrographs of methyl methacrylate casts of intrarenal arteries of aminonucleoside nephrotic rats. As regards luminal diameters, Eff were nearly equal Aff in minor glomerular abnormalities (Minor). Nevertheless Eff of glomeruli with segmental sclerosis (FSHS) were smaller than Aff (t-test). AC with FSHS were smaller than ones of Minor, statistically (t-test). The results of these examination, the cushion may be important factor for the regulation of blood flow in sclerotic glomeruli.

Animals↗
PubMed1989

Study of anionic sites on the mesangium in aminonucleoside nephrosis.

In recent years, various reports have appeared concerning anionic sites in glomerular lesions. However, no detailed results for anionic sites in the mesangium have been reported. The authors therefore prepared nephrotic rats by the administration of puromycin aminonucleoside (PA) and investigated the anionic sites in various mesangial regions, using polyethyleneimine (PEI) as a cationic probe. In the mesangium of the control group as well as the experimental groups, PEI particles were most numerous in the subendothelial regions, followed by the central region and paramesangial region, in that order. In the group treated with PA, the numbers of PEI particles in each mesangial region decreased as compared with those in the control group. Among the three mesangial regions considered, this decrease was most pronounced in the paramesangial region. In the group which received elastase, no significant decrease in numbers of PEI particles was observed in subgroups I and II, indicating maintenance of the anionic sites. The results obtained suggested that regional investigations of the mesangial matrix may be of considerable significance for elucidating the etiologic factors in glomerular sclerosis, and that negative charge impairment in the mesangial matrix plays an important role in the development of glomerular sclerotic lesions.

Animals↗
PubMed1989

[Long-term evaluation of the superior vena cava-pulmonary artery anastomosis in cyanotic heart disease].

We followed up thirty-three patients, to whom the superior vena cava-pulmonary artery anastomosis (Glenn procedure) was undergone between April 1966 and March 1988. There were eighteen patients with single ventricle and nine with tricuspid atresia, two with pulmonary atresia with intact ventricular septum and four with other complex anomalies. Seven patients (21%), including six with single ventricle, died 0.3 to 14.9 years after operation. Regurgitation of common atrioventricular valve was the cause of death in three patients. Serum hemoglobin level fell down from 19.3 +/- 2.2 g/dl preoperatively to 15.3 +/- 1.9 g/dl after operation but increased gradually to the preoperative level about ten years later. The actuarial survival rate at ten years is 80%. Reoperation was performed in 9 patients and reoperation free rate at 10 years is 78%. This analysis suggests that Glenn procedure is still good palliative operation for ten years, although some patients will be necessitated the second operation in future.

Adolescent↗
PubMed1989

Effects of zopiclone on sleep spindles studied with an improved waveform recognition method.

The effects of zopiclone on sleep spindles were analyzed in six normal volunteers by using an improved waveform recognition method. The appearance rate of spindles during stage 2 of NREM sleep showed a significant increase on the drug night, which returned to the baseline on the withdrawal night. The mean duration of spindles was significantly prolonged on the drug night. No definite changes were observed in the average spindle frequency. The mean amplitude of spindles had a tendency to decrease on the drug night. On the withdrawal night, the mean amplitude decreased significantly compared with that of the baseline. Our results indicate that zopiclone is one of the spindle enhancing drugs, and that its property resembles that of benzodiazepines.

Adult↗
PubMed1989

[Report of a case of an atypical huge patent ductus arteriosus].

An atypical huge patent ductus arteriosus (PDA) associated with extreme pulmonary hypertension in a 6-month old female infant was reported. The left 3rd intercostal thoracotomy revealed huge PDA which has an appearance of pulmonary-ductus-descending aorta-trunk (PDDT) on the left side. The right side of the ductus continued to the aortic arch without demarcation between the ductus and the aorta. The median sternotomy clarified the ascending aorta, normal aortic arch, and main pulmonary artery. However, the top of the main pulmonary artery seemed to be fused with the aortic arch. The diagnosis of distal type of aortopulmonary window with wide communication was made and the total circulatory arrest with deep hypothermia and the intracavitary patching for separation of systemic and pulmonary blood flow seemed to be required for the complete repair. Total repair was decided to be postponed one week later and the chest was closed. The patient died of multi-organ failure originating from acute respiratory failure 23 days after exploratory thoracotomy without being repaired. Postmortem examination revealed a huge PDA freely communicating with the ascending aorta and the aortic arch. This is a report of an atypical huge PDA rarely seen and the conventional division or ligation is unfeasible. The circulatory arrest with deep hypothermia and intracavitary patching are obligatory for the surgical repair.

Ductus Arteriosus, Patent↗
PubMed1989

[Successful mitral valve repair and myocardial revascularization in an infant with anomalous origin of the left coronary artery from the pulmonary artery].

An 8-month-old girl of anomalous origin of the left coronary artery from the pulmonary artery associated with severe mitral regurgitation underwent radical operation. She had been in serious cardiac and respiratory failure. Aorto-left coronary arterial continuity was established by intrapulmonary arterial tunnel using Takeuchi's technique. Mitral annulus was plicated by modified Kay's technique. Post-operative course was uneventful.

Coronary Vessel Anomalies↗
PubMed1989

[Combined effect of cisplatin and caffeine on murine B16-BL6 melanoma cells].

Combined effect of cisplatin and caffeine on murine B16-BL6 melanoma cells was studied. Synergistic inhibition of the cell growth was observed when caffeine (2 mM) was added continuously after one hour exposure of cisplatin. On the other hand, when caffeine was added before one hour exposure of cisplatin or one hour simultaneous exposure with cisplatin, synergistic effect was not shown. In the analysis of DNA histogram obtained from flow cytometry, S and G2/M accumulation was observed by the treatment of cisplatin and that accumulation was reduced by the combination of cisplatin and caffeine. From this findings, it was suggested that caffeine would inhibit DNA repair process. Furthermore, according to morphological studies with hematoxylin-eosin stain and Fontana-Masson stain, the addition of caffeine alone resulted in mild swelling of melanoma cells and the decrease of nuclear-cytoplasmic ratio. The combination of cisplatin and caffeine caused marked swelling of melanoma cells and remarkable increase of dendrite-like processes. Melanogenesis was also enhanced by the addition of these two drugs. Many matured melanosomes, increases of mitochondria, Golgi's apparatus and endoplasmic reticula were observed by the use of electron microscope. These findings implied that the combination of cisplatin and caffeine induced a differentiation of murine melanoma cells.

Animals↗
PubMed1989

[Pathomorphological studies on arterial cushion. 1. Rat normal kidney].

The present studies are an attempt to elucidate the vulnerability of focal glomerular sclerosis (FGS). The distribution and morphology of the arterial cushions were studied in rat renal arteries by light microscopy, transmission electron microscopy and scanning electron microscopy (SEM) using of the renal vascular casts. The arterial cushions were observed at a region of the branching arteries from the arcuate arteries and the interlobular arteries. They were extensively demonstrated mainly in the mid cortex and juxtamedullary cortex by the serial sections, but not in the subcapsular cortex. The arterial cushions showed valve-like protrusions and consisted of three components, such as the endothelial cells, the smooth muscular cells and the interstitial ground substances, electron microscopically. The cushions are covered by the endothelial cells which often showed various variation in thickness. Also these had deep processes which elongate into the interior of the cushions. The cells of interior portions of the cushions were modified smooth muscular cells. These cells contained numerous myofibrils and a large number of scattered glycogen granules. No nerve fibers were seen within the cushions. The modified smooth muscular cells were embedded in a loose matrix (probably acid mucopolysaccharides) which contained strands of basement membrane like material. The cushions were observed on the wall of the arcuate and interlobular arteries in the cortex except for subcapsular cortex by SEM. They showed elongated indentation surrounding lumen of their arteries. These results of the observation, the cushion may be important factor for the regulation of blood flow in small arteries and arterioles. The disorder of autoregulation of interlobular arteries due to dysfunction of the cushions with anionic loss were assumed to be one of the important factor in progress to the glomerular sclerosis.

Animals↗