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Biomedical subjects

S P Yang

Publications and source records attributed to S P Yang.

At least 19 recordsLinked to original sources
PubMed1992

Molybdenum requirement of female rats.

Sixty 3-wk-old female Sprague-Dawley rats were randomly divided into six groups of 10 animals each. Group 1 was fed for 8 wk purified AIN-76A diet (basal diet) containing 0.025 mg molybdenum/kg diet. Groups 2-6 were fed the same basal diet supplemented with sodium molybdate to provide total dietary Mo of 0.050, 0.100, 0.200, 0.400 and 0.800 mg/kg diet, respectively. Molybdenum concentration in liver and brain increased linearly up to the 0.200 mg Mo/kg diet level. Beyond this level, no further significant increase occurred. Dietary Mo of 0.100 mg/kg elevated the Mo concentration in heart to its maximal level. Supplementation with 0.025 mg Mo/kg to a total of 0.05 mg Mo/kg diet significantly increased Mo concentration in spleen and kidney; higher levels of dietary Mo did not result in further significant responses. Molybdenum supplementation significantly increased the activities of xanthine dehydrogenase/oxidase (XDH), sulfite oxidase and superoxide dismutase in the liver, and of XDH in small intestinal mucosa. Maximal activities were attained at 0.050, 0.050, 0.200 and 0.100 mg Mo/kg diet, respectively. Dietary Mo of 0.200 mg/kg diet was estimated as the Mo requirement of rats fed the AIN-76A diet.

Administration, Oral↗
PubMed1992

Methylene blue inhibits hypoxic cerebral vasodilation in awake sheep.

Cerebral vasodilation in hypoxia may involve endothelium-derived relaxing factor-nitric oxide. Methylene blue (MB), an in vitro inhibitor of soluble guanylate cyclase, was injected intravenously into six adult ewes instrumented chronically with left ventricular, aortic, and sagittal sinus catheters. In normoxia, MB (0.5 mg/kg) did not alter cerebral blood flow (CBF, measured with 15-microns radiolabeled microspheres), cerebral O2 uptake, mean arterial pressure (MAP), heart rate, cerebral lactate release, or cerebral O2 extraction fraction (OEF). After 1 h of normobaric poikilocapnic hypoxia (arterial PO2 40 Torr, arterial O2 saturation 50%), CBF increased from 51 +/- 5.8 to 142 +/- 18.8 ml.min-1 x 100 g-1, cerebral O2 uptake from 3.5 +/- 0.25 to 4.7 +/- 0.41 ml.min-1 x 100 g-1, cerebral lactate release from 2 +/- 10 to 100 +/- 50 mumol.min- x 100 g-1, and heart rate from 107 +/- 5 to 155 +/- 9 beats/min (P < 0.01). MAP and OEF were unchanged from 91 +/- 3 mmHg and 48 +/- 4%, respectively. In hypoxia, 30 min after MB (0.5 mg/kg), CBF declined to 79.3 +/- 11.7 ml.min-1 x 100 g-1 (P < 0.01), brain O2 uptake (4.3 +/- 0.9 ml.min-1 x 100 g-1) and heart rate (133 +/- 9 beats/min) remained elevated, cerebral lactate release became negative (-155 +/- 60 mumol.min-1 x 100 g-1, P < 0.01), OEF increased to 57 +/- 3% (P < 0.01), and MAP (93 +/- 5 mmHg) was unchanged. The sheep became behaviorally depressed, probably because of global cerebral ischemia. These results may be related to interference with a guanylate cyclase-dependent mechanism.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

N omega-nitro-L-arginine influences cerebral metabolism in awake sheep.

Cerebral vasodilation in hypoxia may involve endothelium-derived relaxing factor-nitric oxide (NO). An inhibitor of NO formation, N omega-nitro-L-arginine (LNA, 100 micrograms/kg i.v.), was given to conscious sheep (n = 6) during normoxia and again in hypocapnic hypoxia (arterial PO2 approximately 38 Torr). Blood samples were obtained from the aorta and sagittal sinus, and cerebral blood flow (CBF) was measured with 15-microns radiolabeled microspheres. During normoxia, LNA elevated (P < 0.05) mean arterial pressure from 82 +/- 3 to 88 +/- 2 (SE) mmHg and cerebral perfusion pressure (CPP) from 72 +/- 3 to 79 +/- 3 mmHg, CBF was unchanged, and cerebral lactate release (CLR) rose temporarily from 0.0 +/- 1.9 to 13.3 +/- 8.7 mumol.min-1 x 100 g-1 (P < 0.05). The glucose-O2 index declined (P < 0.05) from 1.67 +/- 0.16 to 1.03 +/- 0.4 mumol.min-1 x 100 g-1. Hypoxia increased CBF from 59.9 +/- 5.4 to 122.5 +/- 17.5 ml.min-1 x 100 g-1 and the glucose-O2 index from 1.75 +/- 0.43 to 2.49 +/- 0.52 mumol.min-1 x 100 g-1 and decreased brain CO2 output, brain respiratory quotient, and CPP (all P < 0.05), while cerebral O2 uptake, CLR, and CPP were unchanged. LNA given during hypoxia decreased CBF to 77.7 +/- 11.8 ml.min-1 x 100 g-1 and cerebral O2 uptake from 154 +/- 22 to 105.2 +/- 12.4 mumol.min-1 x 100 g-1 and further elevated mean arterial pressure to 98 +/- 2 mmHg (all P < 0.05), CLR was unchanged, and, surprisingly, brain CO2 output and respiratory quotient were reduced dramatically to negative values (P < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Lung volume, diffusing capacity, chest roentgenogram and dyspnea index in interstitial lung disease.

To investigate the physiologic impairment and the role played by pulmonary function tests in interstitial lung disease (ILD), we performed spirometry tests and tested the single-breath carbon monoxide diffusing capacity of 27 patients with diffuse interstitial pulmonary fibrosis (DIPF) and 35 patients with collagen vascular disease (CVD). All of the patients showed irregular linear opacities on their chest X-ray films. Corresponding chest roentgenograms for each patient were evaluated according to the International Labour Organization (ILO) classification. A modified Baseline Dyspnea Index (BDI), which incorporate a patient's physical activity into the recording, was used to quantitate dyspnea. Patients with DIPF demonstrated a comparable reduction in both lung volumes and diffusing capacity. In contrast, patients with CVD had a greater reduction in diffusing capacity than in forced vital capacity (FVC) and total lung capacity (TLC). There were no significant correlations between the type of linear opacities and the severity of the pulmonary function abnormalities, or between the opacities and the dyspnea in either disease group. The profusion of pulmonary infiltrates also did not affect the lung function except for diffusing capacity in patients with DIPF. However, there was a significant loss of FVC, TLC, forced expiratory volume in one second (FEV1) and diffusing capacity with increasing levels of dyspnea. We conclude that pulmonary function parameters may not be equally affected in DIPF and CVD. Approaches using the ILO classification for analysis of chest roentgenograms provide limited information regarding the functional status of patients. Pulmonary functions are significantly related to the extent of a patient's physical activity, if the severity of dyspnea is evaluated carefully using a quantifiable system.

Adult↗
PubMed1990

Lung tumors associated with obstructive pneumonitis: US studies.

Eleven patients who had lung tumors associated with obstructive pneumonitis and who failed to yield diagnostic material at conventional bronchoscopic biopsy underwent real-time ultrasonographic (US) studies and US-guided aspiration biopsy. Sonography of the consolidated lung showed a wedge-shaped hypoechoic lesion containing a fluid bronchogram. The presumed obstructing tumor was seen as a hypoechoic nodule near the hilum or as a well-defined hyperechoic mass inside the partially consolidated lung. Computed tomography (CT) was superior to US in demonstrating the bronchial obstruction (P less than .05). However, there were no significant differences between CT and US in demonstrating the obstructing tumor (P greater than .10). In all 11 patients the diagnosis was made by means of US-guided transthoracic aspiration biopsy and in eight patients also by means of Trucut biopsy. No complications were observed in the studies. It is concluded that US and US-guided aspiration biopsy are useful adjunct diagnostic techniques for lung tumor patients with obstructive pneumonitis.

Aged↗
PubMed1989

Hepatic, placental, and fetal trace elements following molybdenum supplementation during gestation.

The effect of dietary Mo (Na2Mo(4)2H2O) added to drinking water at levels of 0, 5, 10, 50, or 100 mg on hepatic (gestating dams), placental, and fetal Mo, Cu, Zn, and Fe contents of Sprague-Dawley rats was studied. These elements were determined by a polarographic catalytic procedure for Mo and by atomic absorption spectrophotometry for Cu, Fe, and Zn. Hepatic Mo increased two to sixfold (5-100 mg Mo). There was a 1.5-fold increase in hepatic Cu, significant only at the 50 to 100 mg Mo/L treatment levels. Although the hepatic Fe content of the gestating rats significantly increased with Mo supplementation, the extent of the increase appeared to be influenced by the litter size, fetal weights, and the degree of fetal resorption. Zinc values did not differ at any of the treatment levels. Placental Mo increased 3-76-fold, Cu one to threefold. No differences were observed in placenta Fe or Zn. Fetal Mo increased two to six-fold (10-100 mg/L) and Cu increased one to fivefold. There were no differences in the Fe and Zn content although both of these elements appeared to decline as the level of supplemental Mo increased. Significant correlations were also observed between hepatic, placental, and fetal Mo, Cu, Fe, and Zn. These results suggest that changes in trace mineral status in gestation, owing to high Mo intake, do occur and such occurrences are also reflected in the fetus.

Animals↗
PubMed1989

Effect of molybdenum supplementation on hepatic trace elements and enzymes of female rats.

The effects of molybdenum (Mo) supplementation in the drinking water at the levels of 0.1, 0.5, 1.0, 2.0, 5.0 and 10.0 mg/l on the hepatic trace element concentrations and enzyme activities of female Sprague-Dawley rats were studied. The mean hepatic Mo concentration increased significantly in the rats supplemented with 0.1 mg Mo/l as compared to the nonsupplemented rats, but a further significant increase did not occur until the supplementation level reached 5-10 mg Mo/l drinking water. Hepatic copper concentration of the group given 0.1 mg Mo/l and hepatic iron content of the groups given 0.1 or 0.5 mg Mo/l were significantly higher than those of the other groups. The hepatic xanthine dehydrogenase/oxidase activity was not significantly affected by Mo supplementation. The hepatic sulfite oxidase (SOX) activity of the group given 0.1 mg Mo/l was significantly higher than that of the nonsupplemented group. The SOX activities of all the other supplemented groups were at a significantly different level intermediate between the first two. The hepatic superoxide dismutase (SOD) activity was significantly higher in the group given 0.1 mg/l than in the other groups. These results indicated that molybdenum enzymes and SOD might not be participants in previously reported anticarcinogenic activity of Mo, as supplementation at the level of 0.1 mg/l had been observed to be inefficacious in inhibiting N-nitrosomethylurea-induced mammary tumor incidence.

Animals↗
PubMed1989

Clinical experience with percutaneous intra-aortic balloon pumping in cardiogenic shock complicating acute myocardial infarction.

From July 1984 to December 1987, intra-aortic balloon pumping (IABP) was attempted percutaneously to 22 patients at the ages of 37-78 with cardiogenic shock or medically refractory heart failure complicating acute myocardial infarction (CS/MRHF-AMI). There was only one failure because of severe bilateral iliofemoral atherosclerosis. Of the 21 patients undergoing IABP, 17 were in cardiogenic shock and 13 of them showed reversal of shock syndrome after 10 to 48 hours of IABP. Cardiac index increased from 1.91 +/- 0.43 to 2.45 +/- 0.43 L/min/M2 (P less than 0.005), spontaneous systolic arterial pressure rose from 79 +/- 10 to 114 +/- 19 mmHg (P = 0.0001), heart rate dropped from 111 +/- 26 to 85 +/- 13 beats/min (P = 0.0001), pulmonary artery wedge pressure decreased from 29 +/- 5 to 16 +/- 3 mmHg (P = 0.0001), and urine output increased from 7 +/- 10 to 79 +/- 22 ml/h (P = 0.0001). Twelve patients, including 4 shock-free, were subsequently weaned from balloon assistance. Of these patients, 8 (5 shock and 3 nonshock) were discharged from the hospital and followed-up for a mean period of 23 months (4 to 38 months). Of the surviving patients, 4 underwent surgical reperfusion and/or infarctectomy during balloon support (n = 1) or after weaning from IABP (n = 3). All of the 10 patients who underwent coronary angiogram were found a severe left anterior descending artery lesion. The main complication was leg ischemia, which was observed in 7 patients: 3 needed removal or replacement of balloon catheter and one required surgical removal of the thrombus.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

Long-term effect of tiapamil in essential hypertension.

To evaluate the long-term effect of tiapamil, a new calcium antagonist, in hypertension, 20 adult patients suffering from mild to moderate hypertension were entered into a 58-week open study. In 10 patients, blood pressure returned to normal within 1-6 weeks with a daily dose of 600-900 mg tiapamil. In the remaining 10 patients, the blood pressure became normal after 8-28 weeks with a daily dose of 900-1,200 mg tiapamil. The more severe the hypertension, the higher the dose needed and the longer the time required for the blood pressure to return to normal. The overall results at the end of the 58-week treatment showed a significant decrease of the blood pressure to 142 (+/- 9)/88 (+/- 4) mmHg from a before treatment average of 166 (+/- 16)/105 (+/- 7) (p less than 0.001). There was no marked difference in the blood pressure between supine and sitting positions before or after treatment. Side effects were mild and self-limiting, with no patient being dropped from the study. Electrocardiogram (ECG) and laboratory values were not affected during the treatment with the exception of a moderate decrease in the blood glucose. Neither plasma renin activity, nor aldosterone concentration, nor serum cholesterol or triglyceride levels were altered during tiapamil administration. Tiapamil appears to be an effective and well-tolerated drug for use in mild to moderately severe hypertension.

Adult↗
PubMed1988

Ultrasonography of Pancoast tumor.

Eleven patients with Pancoast tumor, who failed to yield diagnostic materials by conventional sputum cytology and fiberoptic bronchoscopy, were studied by real-time linear-array and sector ultrasonography. The sector scanner through the supraclavicular approach adequately visualized the external profile and the internal texture of the lesions in all 11 patients, which is a significant improvement (p less than 0.05) over what can be accomplished with linear-array scanner through the intercostal approach. All patients received percutaneous transthoracic aspiration under ultrasound guidance. Positive cytologic diagnosis was established in ten of the 11 patients (91 percent). Additional biopsies performed in seven patients under similar ultrasonic guidance also provided concordant results. No complications were observed in this series. This study has clearly shown that ultrasound-guided aspiration biopsy can be a safe and useful means for obtaining materials for pathologic confirmation of Pancoast tumor. It may also assist in defining the tumor extension to pleura and adjacent structures.

Aged↗
PubMed1987

Demonstration of persistent left superior vena cava by first pass radionuclide angiography.

A case of the left superior vena cava draining to the coronary sinus without associated intracardiac shunt was initially demonstrated by first pass radionuclide angiography. The patient had atypical chest pain for 8 years, and had sick sinus syndrome with a long cardiac pause. Cardiac catheterization confirmed this diagnosis, and a transvenous pacemaker was successfully implanted through the left superior vena cava.

Aged↗
PubMed1987

Short-course chemotherapy of pulmonary tuberculosis in pneumoconiotic patients.

This is the first prospective clinical trial recorded to date of short-course chemotherapy in pulmonary tuberculosis complicated by pneumoconiosis. Forty-eight anthrasillicotic and 11 silicotic patients with previously untreated pulmonary tuberculosis completed 9-month, short-course chemotherapy regimens: 2 months of daily streptomycin, isoniazid, rifampicin, and pyrazinamide followed by daily isoniazid and rifampicin for 7 months (2SHRZ/7HR). There were 3 treatment failures (5%). The remaining 56 patients (95%) all had their sputum converted within 4 months (mean, 1.5 months). Bacteriologic relapses were noted in 3 patients (5%) after 18 to 40 months of follow-up (mean, 28.4 months). The relapses occurred within 7 months after chemotherapy was stopped. There were 2 deaths from nontuberculosis causes during the follow-up period. Fifty-one patients (90%) remained bacteriologically sterile for 28.4 +/- 6.1 months. These results suggest that the 2SHRZ/7HR regimen is satisfactory in treating anthrasilicotic or silicotic patients with pulmonary tuberculosis, though antituberculosis chemotherapy seemed less effective in patients with pneumoconiosis than in those without pneumoconiosis.

Adult↗
PubMed1986

Influence of source and quantity of protein on the development of immunity and resistance to African trypanosomiasis.

Although it is well documented that severe protein deprivation inhibits the development of the immune response and exacerbates certain infections, little has been done to study the effects of native diets on endemic diseases or immunity. Therefore, protein-restricted diets were formulated for mice to mimic the sources and amounts measured in human diets of the Batouri region of Cameroon, endemic for African trypanosomiasis. Weanling C57BL/6 female mice were fed a diet that contained 73% of the recommended daily allowance (RDA) of protein. The sources of protein were all plant (cornmeal), all animal (casein), or a ratio that reflected the native diet (2.2 parts plant to 1 part animal protein). Diets were isocaloric on a weight basis, equal in lipids, and adequate in vitamins and minerals. Control mice were fed laboratory chow or two times the RDA of animal protein (casein). Mice fed only cornmeal or the native diets consumed as much food but did not gain as much weight as mice fed only animal protein, indicating the poorer quality of protein in their diets. Upon infection with Trypanosoma brucei gambiense, however, significantly higher numbers of these mice controlled the first peak of parasitemia and survived the infection as compared with mice fed the other three diets. Since all mice developed patent infections and the parasite growth rate was unaffected by diet, innate immune factors were ruled out as the cause for the higher level of resistance to the parasite. To determine whether diet affected the development of the immune system, weanling mice were maintained on diets for 30 days before immunization with sheep erythrocytes or trinitrophenylated Ficoll. Mice fed only plant protein or native diets elicited higher direct plaque-forming-cell responses to both the T-cell-dependent and T-cell-independent antigens. Since variant-specific immunity which controls levels of African trypanosomes in the blood is a T-cell-independent humoral immunoglobulin M response, this suggests that cornmeal, a protein of poor quality, was adequate for the development of humoral immunity and resistance to African trypanosomiasis while casein, an animal protein of high quality, was not. This provides more evidence that diet plays an important role in infection and immunity.

Animals↗
PubMed1986

Multiple dietary factors in the enhancement of dimethylhydrazine carcinogenesis: main effect of indole-3-carbinol.

The effects of multiple dietary influences on 1,2-dimethylhydrazine [(DMH) CAS: 540-73-8]-induced colon cancer in rats were studied. A 2(4) factorial experimental design was used to examine the main and interactive effects of 15% wheat bran (WB), 1% cholesterol (CH) with cholic acid, 20% beef tallow (BT), and 0.1% indole-3-carbinol (IC) on 160 male F344 rats treated ip with DMH (10 mg/kg) weekly for 16 weeks. The test diets were fed for 3 weeks before, 16 weeks during, and 12 weeks after DMH administration. At necropsy, total weight gain, liver and spleen weights, serum CH levels, liver aryl hydrocarbon hydroxylase (AHH) activity, and the size, number, incidence, and location of intestinal tumors were analyzed for dietary factor effects. The most significant inducer of tumors was the combination of CH + BT + IC acting in synergism. The single main effect most responsible for tumor morbidity was IC, which appeared to enhance tumorigenesis via its role as an inducer of AHH activity. The WB decreased tumor incidence and burden when added to diets also containing CH, but it otherwise increased tumor burden per tumor-bearing animal and incidence in all other diets. This study demonstrated the need for examining synergistic and antagonistic interactions among dietary initiators and/or promoters of colon carcinogenesis, as well as implicating IC as a significant factor in the development of DMH-induced tumors in rats.

Adenocarcinoma↗