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Biomedical subjects

Y Yasuda

Publications and source records attributed to Y Yasuda.

At least 19 recordsLinked to original sources
PubMed1992

Gastric emptying of tablets and granules in humans, dogs, pigs, and stomach-emptying-controlled rabbits.

Rates of gastric emptying of nondigestible tablets and granules in humans were compared with those in three animal models: dogs, minipigs, and stomach-emptying-controlled rabbits. The rates of gastric emptying of both dosage forms in dogs tended to be faster than or similar to those in humans, whereas the rates in pigs were slower. In stomach-emptying-controlled rabbits, no tablets were emptied from the stomach because of their large size. The rate of gastric emptying of granules in rabbits was slow and variable. Food delayed gastric emptying in dogs, especially for tablets. In rabbits, the rate of gastric emptying of granules was faster when the granules were given before feeding, in comparison with that after feeding or under fasting conditions. We concluded that the dog is a better animal model for bioavailability studies under fasting conditions than the pig and the rabbit.

Adult↗
PubMed1992

Relationship between muscle fatigue and oxygen uptake during cycle ergometer exercise with different ramp slope increments.

The surface electromyogram (EMG) from active muscle and oxygen uptake (VO2) were studied simultaneously to examine changes of motor unit (MU) activity during exercise tests with different ramp increments. Six male subjects performed four exhausting cycle exercises with different ramp slopes of 10, 20, 30 and 40 W.min-1 on different days. The EMG signals taken from the vastus lateralis muscle were stored on a digital data recorder and converted to obtain the integrated EMG (iEMG). The VO2 was measured, with 20-s intervals, by the mixing chamber method. A non-linear increase in iEMG against work load was observed for each exercise in all subjects. The break point of the linear relationship of iEMG was determined by the crossing point of the two regression lines (iEMGbp). Significant differences were obtained in the exercise intensities corresponding to maximal oxygen uptake (VO2max) and the iEMGbp between 10 and 30, and 10 and 40 W.min-1 ramp exercises (P < 0.05). However, no significant differences were obtained in VO2max and VO2 corresponding to the iEMGbp during the four ramp exercises. With respect to the relationship between VO2 and exercise intensity during the ramp increments, the VO2-exercise intensity slope showed significant differences only for the upper half (i.e. above iEMGbp). These results demonstrated that the VO2max and VO2 at which a nonlinear increase in iEMG was observed were not varied by the change of ramp slopes but by the exercise intensity corresponding to VO2max and the iEMGbp was varied by the change of ramp slopes.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Induction of avascular yolk sac due to reduction of basic fibroblast growth factor by retinoic acid in mice.

Vasculogenesis depends on autocrine secretion of basic fibroblast growth factor (bFGF) from capillary endothelial cells. Retinoic acid (RA) induced avascular yolk sac (AVY) of mouse embryos of dams given 60 mg/kg of RA orally on Day 8 of gestation and sacrificed 3 days later. We studied the localization and transcriptional expression of bFGF and FGF-receptor (flg), heparin-binding growth factor (HBGF) activity, localization of lysosomal enzymes and alpha 1-antitrypsin (AAT), and electron microscopy of the normal mouse visceral yolk sac (VYS) and AVY. bFGF, which is normally present in the endoderm of the VYS of 8-day-old embryos and in all components of the VYS by Day 11 of gestation, was reduced in the AVY. However, in the presence of bFGF in vitro capillary nets were restored in the AVY. The mRNA for bFGF was not detectable in either VYS or AVY, while flg mRNA was detected equally in both organs in Northern blotting. The characteristic distribution pattern of lysosomal enzymes, acid phosphatase, lysozyme, and cathepsin D, and AAT was altered in the AVY. The level of acid phosphatase and AAT was reduced to 10% in the AVY. Electron microscopy revealed a partial or total loss of lysosomal membranes where the contents of lysosomes fused with adjacent lysosomes and the external organelles. These results suggest that vitelline blood vessels are not developed by endogenous autocrine bFGF but by exogenous transcellular bFGF from absorptive endodermal cells. Retinoic acid does not affect the angiogenic capacity of the VYS mesenchyme but destroys lysosomes, which release hydrolytic enzymes, leading to degradation of AAT in the endodermal cells and then digestion of endocytosed bFGF.

Acid Phosphatase↗
PubMed1992

Simple method for isolation of primordial germ cells from chick embryos.

A simple one step centrifugation method was developed for purification of primordial germ cells (PGCs) of chick embryos. PGCs, constituting less than 0.1% of the total blood cells of stage 13-14 embryos that contained a microliter amount of blood, were concentrated at the interface of a 6.3% (w/v) and 14.4% (w/v) Ficoll bilayer by centrifugation at 800 x g for 30 min. the purity of these PGCs was 86%, which was 22 times that obtained previously.

Animals↗
PubMed1992

Induction by cortisol of aminopeptidases production from the human placenta in tissue culture.

Human placental aminopeptidase M and A and post-proline endopeptidase are known to act as degrading enzymes of bioactive peptides such as angiotensin II, oxytocin and endogenous opioids. We tested the effects of cortisol on the activities of human placental aminopeptidase A and M and post-proline endopeptidase using short-cultured placental tissues. From 34.5 nM to 3.45 microM of cortisol significantly increased the activities of 3 enzymes. Our present data suggest a possible important role of cortisol in the growth of human placenta via induction of placental aminopeptidases.

Aminopeptidases↗
PubMed1992

Cheiro-oral-pedal syndrome.

The cheiro-oral syndrome is a well-known peculiar sensory disturbance seen around the corner of the mouth and in the palm of the hand on the same side. However, sensory disturbance around the corner of the mouth, in the palm of the hand and in the foot on the same side (cheiro-oral-pedal syndrome) has not been reported until now. We examined 2 cases of cheiro-oral-pedal syndrome; the lesion responsible was confirmed by magnetic resonance imaging to be in the medial lemniscus and in the ventral ascending tract of the trigeminal nerve.

Aged↗
PubMed1992

Sphenoid sinus mucocele with recurrent visual disturbance.

We present a case of sphenoid sinus mucocele with recurrent visual disturbance on the same side. A 22-year-old female showed two episodes of visual disturbance in the left eye for 3 months, and acute retrobulbar optic neuritis was diagnosed. With corticosteroid, visual disturbance improved in 1 week. MRI and CT scans showed mucocele in the left sphenoid sinus, and left optic nerve swelling with high intensity was observed in T2-weighted MRI. No destruction of the optic canal was found. The contiguous inflammation in the optic nerve rather than compression was considered as pathogenesis.

Adult↗
PubMed1992

A method to obtain avian germ-line chimaeras using isolated primordial germ cells.

Primordial germ cells (PGCs), collected from the blood of 2-day-old chick embryos, were concentrated by Ficoll density centrifugation. The blood contained 0.048% PGCs and the concentrated fraction contained 3.9% PGCs in blood cells. The PGCs were picked up with a fine glass pipette, and one hundred were then injected into the terminal sinuses of 2-day-old Japanese quail embryos (24 somites); bubbles were then inserted to prevent haemorrhage. The embryos were further incubated at 38 degrees C for 24 h, and then fixed. Serial sections were stained with the periodic acid-Schiff reagent (PAS) to demonstrate chicken PGCs and with Feulgen stain to identify quail cells. On the basis of the differences in staining properties, 63.6 +/- 5.3 chick PGCs were detected in the quail embryo in the area where the gonads develop. Furthermore, 39.3 +/- 4.5 chick PGCs were incorporated into the quail germinal epithelium within 24 h of the injection. A similar percentage of the host (quail) PGCs had also migrated to the germinal epithelium at the same stage of development. This technique for obtaining germ-line chimaeras will facilitate research on avian germ-line differentiation.

Animals↗
PubMed1992

Effects of blood gas, pH, lactate, potassium on the oxygen uptake time courses during constant-load bicycle exercise.

Changes in the time courses of VO2 during constant-load exercise were examined in connection with other cardiorespiratory and blood chemical parameters. Eleven healthy male subjects performed a ramp exercise and three to six constant-load exercises at varying degrees of load using an electro-braked bicycle ergometer. Heart rate, ventilation, and gas exchange were measured during both types of exercise, and chemical parameters of the subject's blood (blood gas, pH, lactate, and electrolytes) were determined during two intensities of constant-load exercise. The time courses of cardiorespiratory and blood chemical data 3 min after the onset of constant-load exercise were fitted by linear regressions to see whether these parameters had reached the steady state or not. Heart rate increased significantly at a lower intensity of constant-load exercise than VE, VO2, and VCO2. While the increase in VCO2 was slower than that of VO2, a definite difference in time courses was not found between VE and VO2. The time courses of changes in blood gas, pH, bicarbonate, and lactate were not correlated with those of VO2. However, changes in blood potassium concentration were closely correlated with those of VO2 in terms of time courses and magnitude. This suggests the possibility that blood potassium may play an important role in the control of VO2 time course during constant-load exercise.

Adolescent↗
PubMed1992

Ventilatory response to the onset of passive and active exercise in human subjects.

Ventilatory responses at the onset of passive and active exercise with different amount of exercising muscle mass were studied in 10 healthy male subjects. Four exercise tests were performed for each subject with appropriate intervals on the same day, i.e., two voluntary exercises of one leg or both legs and two passive exercises of one leg or both legs. Inspiratory minute volume (VI), end-tidal CO2 and O2 partial pressures (PETCO2, PETO2) were measured breath-by-breath using a hot-wire flowmeter, infrared CO2 analyzer, and a rapid O2 analyzer. Average values of VI were obtained from 5 breaths at rest preceding exercise and the first and second breaths after the onset of exercise. The ventilatory response to exercise was calculated as the difference (delta) between the mean of exercise VI and mean of resting VI. In this study, the PETCO2 decreased by about 0.5 Torr in four exercise tests, though the decrement of PETCO2 was not statistically significant. The average values and standard deviation of delta VI were 4.22 +/- 1.63 l/min for the one leg and 6.46 +/- 1.80 l/min for the two legs in the active exercise, and were 2.46 +/- 1.12 l/min for the one leg and 3.44 +/- 1.55 l/min for the two legs in the passive exercise, respectively. These results suggest that in awake conditions, the ventilatory response at the onset of passive or active exercise does not increase additively with the increasing amount of muscle mass being exercised.

Adolescent↗
PubMed1992

The effects of leg-cooling on blood lactate disappearance following supramaximal exercise.

In order to clarify whether leg-cooling after supramaximal treadmill exercise will change lactate disappearance rate from venous blood, blood lactate, calf blood flow, and skin temperature were determined in cold application and non-cold application recovery. In the cooling experiments, both legs were cooled with ice packs for 23 min during recovery. The skin temperature was significantly lower in the cold application as compared with the non-cold application. However, no significant difference was found in the blood lactate and/or calf blood flow between cold and non-cold conditions. In addition, there was no significant difference in the slope of regression line (blood lactate/blood flow) between cold and non-cold applications. These results suggest that no significant difference in the blood lactate between cold and non-cold applications could be explained by the lack of difference in the blood flow between cold and non-cold applications.

Adult↗
PubMed1992

Protein tyrosine kinase activity in human thyroid papillary carcinoma.

We compared the protein tyrosine kinase (PTK) activity in the acytosolic and particulate fractions of homogenates obtained from 10 papillary thyroid adenocarcinomas with the corresponding activity in 10 specimens from adjacent normal thyroid tissue and 8 follicular adenomas. The cytosolic PTK activity of papillary adenocarcinomas was significantly elevated compared to normal and adenoma tissue. The particulate PTK activity was also significantly elevated in the papillary adenocarcinomas. The cellular distribution of PTK activity (cytosolic activity in percentage) in normal thyroid tissue, adenomas, and papillary adenocarcinomas showed no significant difference (62%, 64% and 63% respectively). These findings indicate that elevated cytosolic PTK activity may be a potentially useful marker for papillary thyroid carcinoma.

Adenocarcinoma, Papillary↗
PubMed1992

[Isolated angiitis of the central nervous system with high immune complex titer, first presenting as intracranial hemorrhage during cesarean section].

A case of isolated angiitis of the central nervous system (IACNS) which first presented as intracranial hemorrhage during cesarean section was reported. The patient was a 27-year-old female who showed severe headache during cesarean section. CT scan disclosed hematoma in the right parieto-occipital area. Carotid and vertebral angiograms demonstrated striking areas of stenosis and irregularity of all intracranial arteries. There was no abnormality in the branches of the external carotid arteries. Systemic angiograms showed no evidence of systemic vasculitis. Biopsy of the temporal artery showed no abnormal findings. Titer of immune complex was elevated. Angiitis showed no improvement with corticosteroid alone, but improved markedly with corticosteroid plus cyclophosphamide. Elevated titer of immune complex became normal. Treatment with a combination of corticosteroid and cyclophosphamide is recommended in IACN.

Adult↗
PubMed1992

The role of mediastinoscopic biopsy in preoperative assessment of lung cancer.

Between 1970 and 1989, mediastinoscopy and thoracotomy were performed on 619 patients admitted to our clinic with lung cancer. When mediastinoscopy was analyzed by lymph node location, the highest sensitivity (95.7%) was for the left paratracheal nodes and the lowest (64.0%) was for nodes at the bifurcation (p < 0.01). The 5-year survivals according to the results of mediastinoscopy were 47% for negative results, 14% for false-negative results, and 6% for positive results. The 5-year survival rate however, was significantly higher (28%) in patients (n = 13) with positive mediastinoscopic findings who underwent complete resection of the primary tumor and all involved nodes than in patients (n = 78) who underwent incomplete resection (p < 0.01). These data support our opinion that patients with positive mediastinoscopic results should not always be excluded from treatment by thoracotomy. The role of mediastinoscopy is not to select patients for thoracotomy but to evaluate lung cancer at the pretreatment stage.

Biopsy↗
PubMed1992

[Chest wall reconstruction using polyester mesh].

Using polyester, we prepared a new material for chest wall reconstruction. The polyester mesh has the same rigidity and elasticity as Marlex tracheal mesh. From January 1987 through July 1991, we performed chest wall reconstruction using the polyester mesh in 8 patients with lung cancer, 9 with empyema after open drainage, 2 with metastatic chest wall tumors, 1 with a primary osteogenic giant cell tumor originating from the rib and 1 with radiation dermatitis and costal chondritis. Three or more ribs were resected in 17 patients. The defects of the chest wall were reconstructed with the polyester mesh covered with a GORE-TEX soft tissue patch to achieve air tightness. Fifteen cases have passed at least one year with no sign of infection. In conclusion, the polyester mesh prevents flail chest and seems to be a satisfactory material for chest wall reconstruction.

Adult↗
PubMed1992

[Sphenoid sinus mucocele with recurrent visual disturbance].

We presented a case with sphenoid sinus mucocele associated with recurrent visual disturbance on the same side. A 22-year-old female showed two episodes of visual disturbance on the left eye for three months. She was diagnosed as acute retrobulbar optic neuritis and was treated with cortico-steroid. In two episodes visual disturbance improved in a week. MRI showed a mucocele in the left sphenoid sinus. No destruction of left optic canal was found in roentgenogram and the left optic nerve showed swelling with high intensity in T2-weighted MRI. Therefore the expansion of inflammation or edema in optic canal rather than direct compression by expanding mucocele was considered as pathogenesis of the visual disturbance. In a case of recurrent and unilateral visual disturbance, a mucocele of posterior paranasal sinus should be suspected in the differential diagnosis.

Adult↗