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Y Sai

Publications and source records attributed to Y Sai.

At least 73 records · Page 4Linked to original sources
PubMed1996

[Predictive value of electrogustometry in the preoperative diagnosis of severity of middle ear pathology].

The chorda tympani nerve (CTN) is frequently damaged in various inflammatory middle ear disorders. To determine the validity of electrogustometry in the diagnosis of preoperative severity of a middle ear lesion of the posteosuperior portion of the mesotympanum, the threshold determined by electrogustometry was examined preoperatively and was correlated with the intraoperative findings. One hundred and six ears of 97 patients with various middle ear diseases were examined. The patients ranged in age from 5 to 70 years (average, 39.4) : 55 of them were male and 42 were female. In 80 of them the appearance of the tympanic membrane on the opposite side was normal. The disorders were classified as follows: A : Non-inflammatory diseases including middle ear anomalies, posttraumatic perforation of the tympanic membranes and congenital cholesteatoma without infection (n = 10) ; B : chronic otitis media without cholesteatoma (n = 14) ; C : pars flaccida retraction type cholesteatoma (n = 34) ; D : pars tensa retraction type cholesteatoma and adhesive otitis media (n = 15) ; E : surgically treated ears (n = 33). The average threshold +/- S.D.(dB) of each group according to the above classification was as follows : A : -1.0 +/- 4.4, B : -1.5 +/- 6.2; C : 7.4 +/- 13.7; D : 9.6 +/- 18.2; E : 20.9 +/- 16.8. The rates of abnormal threshold of electrogustometry (more than 8dB) of A, B, C, D and E were 0%, 7.1%, 44.1%, 46.7% and 72.7%, respectively. The intraoperative findings around the CTN were retrospectively classified according to the following 5 groups : I : No pathological tissue was attached to the CTN (n = 44); II : the Granulation tissue or matrix of the cholesteatoma was attached to the CTN (n = 19) ; III : the CTN was surrounded by granulation or a matrix of cholesteatoma (n = 3) ; IV : The CTN was not identifiable due to the severe pathological condition of the middle ear cavity, in either surgically treated or untreated ears (n = 16), V : Surgically treated ears in which the CTN was identifiable (n = 24). The average threshold +/- S.D.(dB) for I, II, III, IV and V were 1.9 +/- 9.6, 2.0 +/- 11.7, 16.0 +/- 20.3, 32.0 +/- 7.4, 16.0 +/- 17.0, respectively. The rates of abnormal threshold of electrogustometry (more than 8dB) of I, II, III, IV and V were 27.3%, 31.6%, 66.7%, 100% and 62.5%, respectively. In both the above classification by the disorders and that by the intraoperative findings around the CTN, differences in the average thresholds between the surgically treated sides and the opposite sides with normally appearing tympanic membranes showed a tendency similar to that of the thresholds of the treated sides. In the present study, the threshold of electrogustometry was correlated with the disease and the intraoperative findings during middle ear surgery, and it was higher in adhesive otitis media and cholesteatoma of the pars tensa type. Electrogustometry is a useful preoperative examination to predict the condition of the posterosuperior portion of the mesotympanum.

Adolescent↗
PubMed1996

[Comparative study on diode laser (680 nm) and krypton laser mild photocoagulation--histological findings and therapeutic outcome for diabetic maculopathy].

A histopathological study of macaca monkey retina-choroid was carried out for one month after mild photocoagulation with a diode laser (680 nm) and a krypton laser (647 nm). Both lasers produced the same damage to the outer layer of retina and to the melanocytes of 1/3 of the inner choroid. Mild focal photocoagulation was done for 6 patients (12 eyes) with diabetic maculopathy. The patients were 41 to 67 years old, suffering from diabetes mellitus for 5 to 25 years. The grade of their retinopathy was Fukuda's classification AI, AII, and BI. AII eyes were tested before and 3-6 months after photocoagulation for corrected visual acuity, fluorescein angiography, and visual field sensitivity by Octopus automated static perimetry. Visual acuity was stable in all cases. Central sensitivity was better in 2 eyes and unchanged in 4 eyes in both types of laser photocoagulation. In cases of total loss, one eye was improved, 4 eyes were unchanged and one eye was worsened by diode laser photocoagulation and one eye was improved, 2 eyes were unchanged and 3 eyes were worsened by krypton laser photocoagulation. The diode laser (680 nm) might be as useful for ophthalmic laser treatment as the krypton laser.

Adult↗
PubMed1996

[Anesthetic management of a child with pheochromocytoma using sevoflurane, diltiazem and continuous epidural blockade].

A 13-year-old girl with pheochromocytoma was anesthetized for the resection of the tumor. We selected sevoflurane as an inhalation anesthetic in combination with continuous epidural blockade. We administered diltiazem mainly to control hypertension but severe hypertension during the manipulation of the tumor was difficult to control. However, systemic vascular resistance was maintained at a low level and there was no arrhythmia during surgery. This report suggests that the use of diltiazem provides a stable hemodynamic condition for the removal of pheochromocytoma.

Adolescent↗
PubMed1996

The role of vacuolar H(+)-ATPase in the control of intragranular pH and exocytosis in eosinophils.

The presence of vacuolar H(+)-ATPase (V-ATPase) on exocytotic granules in eosinophils and the role of this enzyme in exocytosis were explored in this study. Antibody against 116-kd subunit of V-ATPase positively stained eosinophil granules in immunofluorescence analysis. When eosinophil lysate was extracted immunomagnetically with the same antibody, the extracted fraction contained a considerable amount of eosinophil peroxidase, a marker of eosinophil-specific granules, which indicates that V-ATPase was present on the membranes of eosinophil exsosomal granules. The pH of the eosinophil granules, measured fluorometrically with acridine orange as a delta pH-sensitive dye, was estimated to be 5.1. The acidity of the eosinophil granules was perturbed by bafilomycin A1, a potent selective inhibitor of V-ATPase, which indicates that the low pH of these granules is maintained by V-ATPase activity. BafilomycinA1 and NH4Cl, both of which raise the intragranular pH to neutral, inhibited the eosinophil peroxidase exocytosis induced by platelet-activating factor. These agents did not, however, affect the changes in cytosolic free calcium concentration [Ca2+]i induced by platelet-activating factor. These observations suggest that bafilomycin A1 inhibited a delta pH-requiring step in eosinophil exocytosis that was preceded by the [Ca2+]i transient in the signal transduction pathway, and, hence, the findings suggest the pivotal role of V-ATPase in maintaining intragranular pH and its function of eosinophil exosomal granules.

Ammonium Chloride↗
PubMed1995

cDNA cloning and functional characterization of rat intestinal monocarboxylate transporter.

A cDNA clone which encodes a monocarboxylate transporter (ratMCT1) was isolated from a rat small intestinal cDNA library, which was screened by using full-length MCT1 cDNA of Chinese hamster ovary cells. The ratMCT1 cDNA was sequenced and predicted a protein of 494 amino acids with twelve potential transmembrane domains. The amino acid sequence showed 93.1% and 84.6% identity to the hamster and human monocarboxylate transporters, respectively. When expressed in Xenopus laevis oocytes, the ratMCT1 cRNA caused a significant increase in the uptake of radiolabeled lactic acid. Poly(A)+ RNA transcripts hybridizing to the ratMCT1 cDNA were detected in rat brain, heart, kidney, lung, muscle and brain capillaries. These results indicate that MCT1 contributes to pH-dependent and carrier-mediated transport of monocarboxylic acids in many tissues, not just in the small intestine.

Amino Acid Sequence↗
PubMed1995

Participation of a proton-cotransporter, MCT1, in the intestinal transport of monocarboxylic acids.

A molecular mechanism for the intestinal monocarboxylic acid transport was characterized by using a proton/monocarboxylate transporter, MCT1, in Chinese hamster ovary (CHO) cells, first found by Garcia et al. (Cell, 76, 865-873, 1994). Northern blotting analysis showed that MCT1-isomers exist in the rat and rabbit intestinal enterocytes and Caco-2 cells. The expression of [14C]lactic acid uptake by Xenopus laevis oocytes injected with rabbit intestinal mRNA was reduced by hybridizing the mRNA with a MCT1 cDNA of CHO cells before microinjection used as the antisense DNA. [14C]Lactic acid uptake by CHO cells was pH dependent, saturable, stereospecific, and reduced in the presence of acetic acid, benzoic acid, S- and R-ibuprofen, S- and R-mandelic acid, nicotinic acid, pravastatin, propionic acid and valproic acid. In addition, several monocarboxylic acids were transported in pH-dependent and saturable manners. These results suggest that the intestinal MCT1-related protein contributes to a carrier-mediated absorption for organic weak acid compounds.

Animals↗
PubMed1995

Comparison of responses of canine pulmonary artery and vein to angiotensin II, bradykinin and vasopressin.

Responses to angiotensin II, bradykinin and arginine vasopressin were compared in helical strips of canine pulmonary arteries and veins. Angiotensin II contracted the artery but relaxed the vein strip. The artery contraction was augmented by indomethacin and aspirin and was abolished by losartan. The vein relaxation was not affected by endothelium denudation but was abolished by the cyclooxygenase inhibitors, a prostaglandin I2 synthase inhibitor and losartan. The bradykinin-induced artery relaxation was inhibited by endothelium denudation, NG-nitro-L-arginine (L-NA) or indomethacin and abolished by their combined treatment. The vein relaxation produced by bradykinin was endothelium-independent and was abolished by indomethacin. Vasopressin produced a slight relaxation in the arteries, which was abolished by endothelium denudation and L-NA. The vein relaxation produced by vasopressin was abolished by endothelium denudation and combined treatment with L-NA and indomethacin. It may be concluded that (1) activation of angiotensin AT1 receptor subtype in smooth muscle produces contraction and also relaxation due to prostaglandin I2 release; the former predominates over the latter in the artery, whereas only the latter is operative in the vein, (2) the bradykinin-induced relaxation is due to nitric oxide (NO) from the endothelium and prostaglandin I2 from subendothelial tissues in the artery and solely to prostaglandin I2 in the veins, and (3) the vasopressin-induced relaxation is mediated by endothelial NO in the artery, and NO and prostaglandin I2 in the vein.

Angiotensin II↗
PubMed1995

Metabolic interconversion of acid metabolites of cotinine in vitro.

The in vitro metabolism of 4-(3-pyridyl)-4-oxo-butyric acid (POBA), 4-(3-pyridyl)-4-hydroxy-butyric acid (PHBA) and 5-(3-pyridyl)-tetrahydrofuranone-2 (PTHF) by hepatic fractions from different experimental animal species (rat, rabbit, hamster, guinea-pig) was studied. The results show that POBA can be reduced to PHBA followed by cyclisation to PTHF by enzymes present in the cell soluble fraction. Conversely PHBA can be oxidised to POBA in vitro by microsomal enzymes. The metabolic transformations observed are predominantly catalysed by enzymes. PTHF is transformed to PHBA by a chemical hydrolytic reaction which is enhanced by both microsomal and soluble enzymes. Under our HPLC analytical conditions, neither 3-pyridylacetic acid nor 4-(3-pyridyl)-butyric acid were detected. Among the four species studied, there was a significant difference in the reduction of POBA to PHBA, with rabbit and hamster having the stronger activity. When the three compounds were incubated with hepatic tissue from rats induced separately with phenobarbitone (PB), beta-naphthoflavone (beta NF) or arochlor-1254 (A-1254), no difference in interconversion of the metabolites was observed when compared to non-induced rats. Therefore, it is suggested that these interconversions of the compounds are probably not mediated by cytochrome-P450 isoenzymes. A consideration of the ratios of individual processes leads us to believe that the conversion of POBA to PHBA is on the major pathway in the degradation of continine to 3-pyridylacetic acid.

Animals↗
PubMed1994

Cytosol treated with GTP gamma S disintegrates lysosomes in vitro.

Cytosol that was treated with guanosine 5'-O-(3-thiotriphosphate) (GTP gamma S) disintegrated lysosomes in a dose dependent manner, as detected by the release of preloaded fluorescein isothiocyanate-dextran from lysosomes. This phenomenon is a consequence of the two successive steps of incubation, (i) the treatment of cytosol with GTP gamma S, and (ii) the disintegration of lysosomes by the treated cytosol. The first step was specific for GTP gamma S and the effect of GTP gamma S was suppressed by GTP or GDP. The second step required ATP but it was not affected by bafilomycin A1. GTP gamma S treatment of lysosomes themselves did not induce their lysis. The lytic "factor(s)" produced in GTP gamma S-treated cytosol consisted of high molecular weight protein(s).

Adenosine Triphosphate↗
PubMed1994

[Sick sinus syndrome discovered after induction of general anesthesia in a patient with normal preoperative Holter ECG].

We reported a case of 50-year-old male who was found to have SSS after induction of general anesthesia though his preoperative cardiac function studies including Holter ECG were normal. He was scheduled to have anterior transposition of ulnar nerve for idiopathic ulnar nerve palsy. He had suffered from lung edema during the same operation about 10 months previously at another hospital and the cause had been unknown. We monitored direct radial artery pressure continuously before induction of general anesthesia. About 5 minutes after the induction, ECG showed bradycardia of less than 40.min-1 and systolic blood pressure decreased to 40 mmHg. Intravenous injection of atropine increased heart rate to 60.min-1 only transiently. We began continuous infusion of isoproterenol. It was effective and no bradycardia and hypotension occurred afterwards throughout the operation. About 2 months later, he showed severe dizziness and Holter ECG revealed sinus arrest for 5 seconds. Therefore, a permanent pacemaker was implanted.

Anesthesia, General↗
PubMed1993

Inhibition of cell growth by bafilomycin A1, a selective inhibitor of vacuolar H(+)-ATPase.

Bafilomycin A1, a potent selective inhibitor of vacuolar H(+)-ATPase, inhibited the growth of a variety of cultured cells dose-dependently, including golden hamster embryo and NIH-3T3 fibroblasts, whether or not they were transformed, and PC12 and HeLa cells. The concentration of bafilomycin A1 for 50% inhibition of cell growth ranged from 10 to 50 nM. The dose response was nearly parallel with that of the bafilomycin A1-induced lysosomal pH increase. The degree of pH increase for growth inhibition produced by bafilomycin A1 was similar to that produced by NH4Cl in which little difference was recognized in effect among cell types.

3T3 Cells↗
PubMed1993

Metastasis of renal cell carcinoma to the contralateral renal pelvis.

Extremely rarely renal cell carcinoma metastasizes to the contralateral renal pelvis or ureter. The present report concerns a case where a metastatic tumor could be successfully removed from the left renal pelvis 3 years after right nephrectomy for the primary tumor. A review of the literature revealed this to be only the fourth such case documented.

Carcinoma, Renal Cell↗
PubMed1993

[A new leak test of anesthetic machine].

A case of the inspired PCO2 increase secondary to the malfunction of expiratory valve due to a defected edge of creator is presented. In this case, we could not detect the malfunction of expiratory valve using the preanesthetic routine leak test but found it by observing the expiratory phase of the capnometric curve. Therefore, we devised a new leak test for checking the malfunction of inspiratory and expiratory valves. This test is simple and effective. The test consists of the following procedures.: 1. Connecting yokes to the oxygen piping system. 2. Connecting the breathing bag. 3. Occluding the inspiratory terminal. Closing the semiclosed valve completely. 4. Flushing the O2 gas and increasing the pressure of breathing circuit to 30 cmH2O. 5. Monitoring the pressure gauge of the anesthesia system. If the function of valves is normal, the system pressure decreases slowly. If either of the valves works wrong, it decreases rapidly. We checked anesthesia machines in our facilities using the new leak test, and found some cases of the expiratory valve malfunctions.

Adenocarcinoma↗
PubMed1992

Pituitary apoplexy following cholecystectomy.

A case of pituitary apoplexy, which presented with hyperaesthesia in the distribution of the ophthalmic division of the left trigeminal nerve and a left sixth nerve palsy following cholecystectomy, is reported. Computed tomography and magnetic resonance imaging revealed a large intrasellar mass which extended laterally into the left cavernous sinus and showed evidence of old and recent haemorrhage within the tumour. This case demonstrates that patients who present with unusual neurological symptoms involving the cranial nerves after general anaesthesia, should undergo neurological and radiological investigations.

Analgesia, Epidural↗
PubMed1992

Effect of halothane, fentanyl, and ketamine on the threshold for transpulmonary passage of venous air emboli in dogs.

We assumed that the capacity of the lungs to filter gas bubbles would vary as a function of anesthetic management. The effects of halothane (1% inspired concentration [group 1, n = 8]), fentanyl (100 micrograms/kg IV, followed by 1 micrograms.kg-1.min-1 [group 2, n = 7]), and ketamine (10 mg/kg IV, followed by 0.2 mg.kg-1.min-1 [group 3, n = 6]) on the passage of bolus injections of air across the pulmonary circulation were studied in dogs by using transesophageal echocardiography to detect air in the left atrium or the aorta, or both. The thresholds for bolus air detection during halothane, fentanyl, and ketamine administration were 0.05 mL/kg (range 0.01-0.1), 0.5 mL/kg (range 0.2-1.0), and 0.35 mL/kg (range 0.1-0.5), respectively. We conclude that the threshold during fentanyl- or ketamine-induced anesthesia was significantly higher than during halothane-induced anesthesia. Therefore, halothane interferes with the capacity of the lungs to filter air from the pulmonary circulation.

Animals↗