Search PubMed⌕ Search

Biomedical subjects

S C Yang

Publications and source records attributed to S C Yang.

At least 127 records · Page 7Linked to original sources
PubMed1989

The response pattern of patients with chronic airway obstruction to bronchodilators.

To investigate the response pattern of patients with chronic airway obstruction (CAO) to bronchodilators, 128 subjects consisting of 80 men and 48 women with a mean age of 52.6 years were randomly tested with three inhalant bronchodilators: a non-selective beta-agonist (isoproterenol), a beta 2-selective agonist (terbutaline) and an anticholinergics (ipratropium) plus placebo. All patients had a baseline FEV/FVC of less than 65% and their clinical diagnosis were classified as either COPD or bronchial asthma according to the criteria of the ACCP-ATS Joint Committee on Pulmonary Nomenclature. The drugs were delivered to the patient via a metered dose inhaler (MDI) using the conventional inhalation technique. Spirometry was measured at regular intervals with a computerized pulmonary function analyzer CHESTAC-65(Japan). A more than 15% increase in FEV1 and/or FVC after treatment was regarded as responsive. While 108 patients were tested with a single drug, the remaining 20 patients were tested sequentially with terbutaline, ipratropium and placebo in a randomized cross-over manner for studying additivity. Our results showed that the response rates of asthmatic patients to isoproterenol, terbutaline and ipratropium were 50%, 87% and 67%, respectively. Only 27% of COPD patients responded to isoproterenol and 60% to terbutaline. On the other hand, ipratropium possessed a 61% response rate in the treatment of COPD and showed a bronchodilator effect independent to that of terbutaline. Combined use of both drugs resulted in additional improvement. Once patients responded to the drugs, apparent changes in FEV1 and/or FVC occurred within 30 minutes and reached the maximum usually at 60 minutes post-inhalation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

Recommended safe practices for using the neurotoxin MPTP in animal experiments.

The metabolism and distribution of the parkinsonian syndrome inducing neurotoxin MPTP has been studied in non-human primates and mice housed in controlled environmental chambers. 14C6-MPTP was prepared and injected at concentrations normally employed for lesioning experiments (30 mg/kg in mice, 0.3 mg/kg in monkeys). All interior surfaces of the chambers which could be reached by animals or their excreta were contaminated with radiolabeled metabolites. Vapor born unmetabolized MPTP was negligible, although significant amounts of MPTP were found in the excreta of mice (less than or equal to 15% injected dose) and small amounts from rhesus monkeys (less than 2%). Procedures to minimize contact with animal fur, bedding and excreta should protect investigators working with MPTP over extended periods. Permanganate oxidation effectively detoxifies solutions of MPTP. MPTP, MPP+, common synthetic intermediates, and the products of MPTP's oxidation are not mutagenic as measured by a Salmonella-microsome assay.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗
PubMed1986

Detection of right atrial mass by echocardiography in pulmonary thromboembolism.

An echodense mass in the right atrium was detected incidentally by two-dimensional echocardiography (ECHO) in a patient with clinical suggestions of cardiogenic shock. Autopsy revealed a cylindrical thrombus extending from the right atrium through a patent foramen ovale, and bilateral massive pulmonary thromboembolism (PTE). Pulmonary thromboembolism should be one of the differential diagnoses in patients with an echodense mass in the right heart.

Diagnosis, Differential↗
PubMed1986

Oxygen delivery and consumption and P50 in patients with acute myocardial infarction.

We investigated the relationship between oxygen delivery (DO2), oxygen consumption (VO2), and influence of oxyhemoglobin dissociation (P50) on VO2 in 40 patients with complicated myocardial infarction. A decrease in VO2 and an increase in P50 were observed as DO2 decreased due to pump failure. In a given range of DO2, VO2 was related to P50 in survivors (r values .472 to .647, p less than .01). Each millimeter of mercury increase in P50 was associated with a 5.2 to 6.5 ml/min X m2 increase in VO2 when DO2 was less than 450 ml/min X m2. No similar correlation was found for nonsurvivors. Lactate was higher in nonsurvivors despite the fact that DO2 and VO2 were similar in the two groups. The lack of compensatory increases in P50 may be pathologic in nonsurvivors. However, the value of VO2 as an indicator of tissue oxygenation or survival in patients with acute myocardial infarction is questionable.

Adult↗
PubMed1986

Role of preoperative hemodynamic monitoring in intraoperative fluid management.

In this study the hemodynamic factors which contribute to postoperative mortality and morbidity were evaluated in 41 patients. Preoperative data were prospectively collected over a 5-year period. The patients underwent vascular and general surgical operative procedures. Among them, 23 patients had minor or no postoperative complications (group 1) and 18 patients suffered serious complications or died (group 2). Preoperative cardiac function was better in group 1, but both groups achieved their best cardiac index (CI) with fluids or pharmacologic manipulation preoperatively. Group 2 patients had longer operations, more blood loss, and were significantly hypovolemic postoperatively as indicated by lower pulmonary arterial wedge pressure (PAWP) and CI in comparison to the best preoperative values. When postoperative PAWP was higher than or within 3 mm Hg of the best preoperative level, complication rate was 14 per cent (3 of 21). In 15 of the 19 or 79 per cent of the patients, postoperative complications developed when PAWP decreased by 4 mm Hg or more. The difference in complications was significant (P less than 0.01). However, commonly measured parameters such as the amount of fluid infused, urine output, immediate postoperative heart rate, blood pressure, central venous pressure, and hemoglobin failed to reveal hemodynamically significant hypovolemia or lacticacidemia in group 2. The authors were unable to demonstrate a reduction in mortality or morbidity in group 2 patients in whom serious technical operative difficulties were also encountered.

Aged↗