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Biomedical subjects

Y Fukuda

Publications and source records attributed to Y Fukuda.

At least 721 records · Page 40Linked to original sources
PubMed1989

Ultrasonographic findings in gastric cancer: in vitro and in vivo studies.

Ultrasonography was performed in 45 cases of gastric cancer. Specimens from all 45 cases of gastric cancer were subjects to ultrasonographic study by the water immersion method for comparison with histology. In 32 of these 45 cases in vivo ultrasonographic evaluation was performed prospectively. The overall accuracy rates for the diagnosis of the depth of cancerous invasion were almost 80% in both in vitro and in vivo studies. In vivo ultrasonographic findings agreed well with those from the specimen studies. Ultrasonography was considered to be useful in the diagnosis of gastric malignancies.

Humans↗
PubMed1989

In vitro capacitation of boar ejaculated spermatozoa: effect of conditioned media prepared from preincubated sperm suspension.

The fertilizing ability of boar ejaculated spermatozoa was examined in vitro after preincubation at a concentration of 2.5 x 10(8)/ml for 4 hr in several conditioned media (CM). For preparation of CM, boar spermatozoa were incubated in a modified Krebs-Ringer bicarbonate solution (TYH) at concentrations of 20 to 40 x 10(8)/ml for several hours up to 4 hr; then their supernatant fluids were collected by centrifugation. When boar ejaculated spermatozoa were preincubated in TYH alone, 14.1% of oocytes were penetrated by them as we reported previously. On the other hand, preincubating them with CM, their fertilizing ability was elevated according as the incubation time of CM preparation was lengthened. The fertilization rate reached 75.0%, using 4 hr-incubated CM for the preincubation medium. The effect of CM was not deteriorated by heat treatments (56 degrees C, 30 min, or 100 degrees C, 5 min). The components of CM were separated at a molecular weight of 25,000 by ultrafiltration, and high fertilization rate (69.8%) was obtained when low molecular weight fraction was used for the preincubation medium. Sperm extracts prepared from directly frozen-thawed sperm suspension and 0.1-10 mM of taurine or hypotaurine had no effect on the fertilizing ability of boar spermatozoa. These results suggest that substances stimulating boar sperm capacitation were accumulated from viable spermatozoa into the medium during incubation and that the effective substances were heat-stable and of low molecular weight and were not taurine and hypotaurine.

Animals↗
PubMed1989

Effect of disuse on the ultrastructure of the achilles tendon in rats.

We examined the influence exerted, through disuse of the hindlimb, on the collagen fibres of the achilles tendon in rats. With disuse the body mass decreased by 28%, and the mass of soleus muscle decreased by 20%. A decrease in the surface area and diameter was observed in the experimental group when compared to the control group. A histogram of the collagen fibres showed a decrease of the thick fibres in the experimental group. The maximum surface area of collagen fibres in the experimental group was seen to be only 43% of that of the control group. These results showed a decrease in the thickness of the collagen fibres of the achilles tendon through disuse. This seemed to suggest that resistance to tension is decreased by disuse.

Achilles Tendon↗
PubMed1989

Angiomyolipoma of the colon: a new entity in colonic polypoid lesions.

A 67-year-old man with angiomyolipoma on the sigmoid colon is reported. The colonic polyp was pedunculated and diagnosed histologically after endoscopic polypectomy. Angiomyolipoma is one of the benign hamartomas arising principally in the kidneys of patients with or without tuberous sclerosis. Extrarenal angiomyolipoma is rare and this may be the first report of colonic angiomyolipoma.

Aged↗
PubMed1989

Evolution of metaplastic squamous cells of alveolar walls in pulmonary fibrosis produced by paraquat. An ultrastructural and immunohistochemical study.

Sequential histologic, ultrastructural, immunohistochemical and morphometric studies were made of the evolutional changes of metaplastic and regenerating alveolar epithelial cells in monkeys from 3 days to 8 weeks after paraquat administration. In the early proliferative phase, many alveoli were lined by single-layered and stratified squamous epithelium and bronchiolized epithelium (i.e., presumably derived from bronchi and bronchioles). The regenerating epithelial cells had well developed bundles of actin-like filaments, which were arranged parallel to the basal surfaces of the cells and were associated with zonulae adherentes; these cells also had intermediate filaments and some desmosomes, but lacked basement membranes, hemidesmosomes and anchoring fibrils. They covered either denuded, wavy and disrupted original epithelial basement membranes or areas of developing intraalveolar fibrosis. In zones of squamous epithelial cell metaplasia associated with intraalveolar fibrosis, fibronexus-like structures appeared to be responsible for the initial adhesion of the cells to the underlying connective tissue. In later phases, single-layered and stratified squamous epithelial cells disappeared, and only bronchiolized epithelial cells, with hemidesmosomes and anchoring fibrils on their basal surfaces, were found in fibrotic alveoli. Although bronchiolized and squamous metaplastic epithelial cells are generally thought to be formed as late events in pulmonary damage, such cells play an important role in early, temporary repair of damaged alveoli.

Animals↗
PubMed1989

Endothelin is a potent mitogen for rat vascular smooth muscle cells.

The effect of endothelin (ET), a novel endothelium-derived vasoconstrictive peptide, on DNA synthesis was studied in cultured rat vascular smooth muscle cells (VSMC). ET stimulated incorporation of [3H]thymidine into DNA of the quiescent VSMC in a dose-dependent manner; the approximate half-maximal and maximal stimulation for DNA synthesis was induced with 2 x 10(-10) M and 10(-9) M, respectively. The stimulatory effect by ET on DNA synthesis was completely inhibited by the calcium channel blocker nifedipine. ET combined with epidermal growth factor and transforming growth factor-alpha, but not with platelet-derived growth factor, had synergistic effects. These data indicate that ET is a potent mitogen as well as a constrictor for VSMC, suggesting its potential role in the development of vascular disease.

Animals↗
PubMed1989

Morphogenesis of abnormal elastic fibers in lungs of patients with panacinar and centriacinar emphysema.

Pulmonary elastic fibers in a patient with panacinar emphysema due to alpha-1-antitrypsin deficiency and three patients with centriacinar emphysema related to anthracosis were studied by electron microscopy and by light and electron microscopic immunohistochemistry for elastin. Four types of abnormal elastic fibers were found: (1) finely disrupted fibers, (2) fibers with vacuolar changes and deposits of electron-dense granular material, (3) accumulations of small, rounded amorphous components of elastic fibers near bundles of microfibrils, and (4) large, confluent masses consisting mainly of aggregates of irregularly and compactly arranged, small-sized amorphous components. The amorphous components in these four types of abnormal elastic fibers tended to stain evenly with antielastin antibody. This is attributed to greater penetration of antielastin antibody into fibers that were incompletely polymerized because of immaturity or hydrolytic damage. Finely disrupted fibers were frequently found in the patient with panacinar emphysema and were presumed to have been damaged by elastase. The other three types of elastic fibers were frequently found in the patients with centriacinar emphysema. The vacuoles and electron-dense deposits in elastic fibers probably represented the consequence of damage to elastic fibers. The small round amorphous components in elastic fibers might be formed from abnormal elastogenesis. The large, confluent elastic masses were thought to be formed by the aggregation of elastic fibers in areas of coalescence of alveolar walls undergoing structural remodeling.

Adult↗
PubMed1989

Developmental ability of porcine ova matured in porcine follicular fluid in vitro and fertilized in vitro.

Developmental ability of porcine ova matured in porcine follicular fluid (pFF) with FSH in vitro and fertilized in vitro was examined by culturing in BMOC-2. Forty-eight hours after insemination, 35.6% of ova cleaved normally, and this rate was significantly higher (13.0%) than that of the ova matured in a modified Krebs-Ringer bicarbonate solution. Twenty-four percent (29 120 ) of ova matured in pFF with FSH developed to the four-cell stage and two of them developed to the eight-cell stage 66 h after insemination. Most cleaved embryos stopped developing at the four-cell stage and neither the morula nor blastocyst stage was observed throughout the culture period as reported in the in vivo matured ova. In culture at 37 degrees C, the appearance of two-cell and four-cell embryos was delayed from that of in vivo embryos, but their development was significantly accelerated by culturing at 39 degrees C. These results show that pFF is an excellent maturation medium for porcine oocytes, and the developmental capacity of the ova matured in pFF seems to be similar to that of in vivo matured ova. Culturing at 39 degrees C was found to be more suit-able for the development of ova than 37 degrees C.

Journal Article↗
PubMed1989

Autonomic nerve and cardiovascular responses to changing blood oxygen and carbon dioxide levels in the rat.

Contribution of autonomic nervous system activity to the heart rate and blood pressure responses during chemoreceptor excitations by systemic hypoxia and hypercapnia and to hyperoxia and hypocapnia was analyzed in the urethane-anesthetized, artificially ventilated rats. Systemic hypoxia induced a co-activation of two antagonistic nerves: an increase in cardiac sympathetic and in cardiac vagal efferent nerve discharges. Increased heart rate was due to predominance of the cardiac sympathetic over the cardiac vagal activation. In spite of a marked reflex increase in the renal and cardiac sympathetic nerve activities, the local vasodilator effect of hypoxia prevented consistent changes in arterial blood pressure. Bilateral section of the carotid sinus nerves (CSN) mostly abolished autonomic nerve responses and produced a profound decreases in the blood pressure during hypoxia. Hyperoxia elicited a pressor response due to peripheral vasoconstriction with no significant change in the autonomic nerve activities except for a decrease in the cardiac sympathetic nerve discharges. Hypercapnia significantly increased blood pressure and renal nerve sympathetic activity. In contrast to hypoxia, hypercapnia excited cardiac sympathetic and inhibited cardiac vagal activity. This reciprocal effect did not elicit neurogenic cardioacceleration, because it was masked by the local inhibitory action of CO2 on the heart rate. The increase in sympathetic activities and in blood pressure during hypercapnia persisted after bilateral CSN section indicating that the responses were mediated by central rather than by peripheral chemoreceptors. Hypocapnia produced a significant increase in cardiac vagal discharges yet a cardioacceleratory response occurred due to the local effect upon heart rate. The present results indicate that in the rat, autonomic nervous responses differ depending on the type, i.e. hypoxic or hypercapnic, chemoreceptor stimuli. Reflex heart rate and blood pressure responses do not follow the autonomic nerve activities exactly. Circulatory responses are greatly modified by local peripheral effects of hypoxic, hyperoxic, hypocapnic or CO2 stimuli on the cardiovascular system. Species differences characterizing the autonomic nerve responsiveness to chemical stimuli in the rat are described.

Animals↗
PubMed1989

Granular cell ameloblastoma. A rare variant.

A rare case of granular cell ameloblastoma in the anterior mandible of a 59-year-old man has been studied by light and electron microscopy. In some areas, the tumor was very similar to an oncocytoma (oxyphilic adenoma). Almost all tumor cells were full of eosinophilic granules, whereas in the common type of granular cell ameloblastoma, only the cells located in the central portion of the tumor are granular.

Adenoma↗
PubMed1989

Factors causing hyperkalemia in premature infants.

In order to clarify the causative factors of hyperkalemia in premature infants, 48 newborn infants less than 2000 gm birthweight were examined during the first 48 hours of life. They were divided into two groups: group A (n = 19), which had more than 7 mEq/liter of serum potassium level, was defined as a hyperkalemic group; group B (n = 29) had less than 6.9 mEq/liter of serum potassium level throughout this study period. In group A hyperkalemia occurred on the first day of life and continued throughout the study period. Five of group A infants had arrhythmia, one of whom died from cardiac arrest on the second day of life. Laboratory findings (serum creatinine, creatine phosphokinase, electrolytes, blood gas analysis, calorie balance, and renal function) were compared between the two groups. On the first day of life, serum creatinine and creatine phosphokinase concentrations were significantly elevated and calorie intake was decreased in group A when compared with group B. On the second day of life, calorie intake, urine volume, creatinine clearance, and base excess were significantly decreased in group A. A significant decrease was observed in the serum calcium level in group A on the second day of life when compared with admission data. These data suggest that neonatal hyperkalemia may occur in the sick newborn infants with renal dysfunction when combined with metabolic acidosis and catabolic state.

Acidosis↗
PubMed1989

Na,K-ATPase activity in renal tubule cells from Milan hypertensive rats.

Several abnormalities of cation transport have been described in the Milan hypertensive rats (MHS). In this study we examined Na,K-ATPase activity in proximal convoluted tubules (PCT) cells and medullary thick ascending limb of Henle cells (TAL) from MHS and from the Milan normotensive rats (MNS). Na,K-ATPase activity was determined as 32P-ATP hydrolysis in single tubule segments. Na,K-ATPase activity (pmol Pi/mm t/h) was significantly higher in MHS than MNS both in PCT (903 +/- 227 n = 8 v 506 +/- 285 n = 12) and TAL (4324 +/- 800 n = 5 v 3063 +/- 625 n = 5). Na,K-ATPase dependent respiration was determined in PCT cell from MNS and MHS. Under basal condition Na,K-ATPase dependent respiration (mumol O2/mg protein/h) was higher in MHS than in MNS (24.2 +/- 1.8 n = 5 v 16.1 +/- 0.4 n = 5). When the cells were Na loaded by amphotericin Na,K-ATPase dependent respiration increased significantly more in MHS than MNS (38.4 +/- 1.6 v 26.8 +/- 2.2 n = 4). Thus, Na,K-ATPase activity is higher in renal tubule cells both at normal intracellular Na and after the cells have been Na loaded. The results indicate that regulation of Na homeostasis in renal tubule cell is different in MHS and MNS.

Amphotericin B↗
PubMed1989

Expression of oncogenes during rat chemical hepatotumorigenesis promoted by estrogen.

To elucidate the role of oncogene expression in hepatocarcinogenesis, we examined the expression of 4 cellular oncogenes (c-myc, c-fos, Ha-ras and c-erbA) in liver tissues induced by chemical agents. Four groups of male Sprague-Dawley rats were examined in the present study. Rats of the first and second groups were given a single intraperitoneal injection of diethylnitrosamine (DEN), 200 mg/kg body weight. Two weeks later, these rats were divided into two groups; the DEN-C group received no further medication, whereas the DEN-DES group was given diethylstilbestrol (DES), 0.5 mg/day, for 12 months. The DEN group was given DEN, 100 ppm, in drinking water for five months as the hepatocellular carcinoma (HCC) group. The DES group was given DES, 0.5 mg/day, from the start for 8 months. Rats of the DEN-DES and DEN groups developed grossly visible hepatic tumors. Significantly higher levels of c-myc gene expression were observed in tissues of HCC of the DEN group and in neoplastic nodules of the DEN-DES groups than in the DES and DEN-C group. The increase of c-myc mRNA seemed to begin after 1 month of treatment and became significant at 4 months in the DEN-DES group. On the other hand, no significant differences in mRNA levels of c-fos, Ha-ras and c-erbA were observed among these four groups. Although the significance of increased c-myc gene expression in neoplastic liver is still not known, it is conceivable that the persistent elevation of c-myc gene expression in the DEN and DEN-DES groups might contribute to the development of rat chemical hepatotumorigenesis.

Animals↗