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Biomedical subjects

C T Yang

Publications and source records attributed to C T Yang.

At least 37 records · Page 2Linked to original sources
PubMed1997

Respiratory drive and pulmonary mechanics during haemodialysis with ultrafiltration in ventilated patients.

The improvements of respiratory drive and pulmonary mechanics which follow haemodialysis with ultrafiltration in mechanically ventilated renal failure patients seem predictable but have not been studied before. In this study, 14 renal failure patients with stable haemodynamics mechanically ventilated with pressure support ventilation (PSV) were enrolled. Respiratory drive (represented as P0.1), pulmonary mechanics, breathing pattern, arterial blood gas and haemodynamics were measured according to the time schedule: pre-dialysis (Time 0), and at 60, 120, 180, 240 minutes thereafter. Following the removal of excess lung water during haemodialysis, auto-PEEP and patient's work of breathing (WOBp) decreased gradually. P0.1 lessened progressively along with the improvement in pulmonary mechanics. The changes in auto-PEEP and WOBp correlated closely to the pre- and post-dialysis decline of P0.1 (delta P0.1). There was a negative, moderately significant correlation between the amount of fluid ultrafiltrated during dialysis (delta UF) and the delta P0.1 (R = -0.54). The breathing pattern remained stable during dialysis. No hypoventilation or hypoxaemia occurred despite the development of metabolic alkalosis induced by bicarbonate dialysate. We have shown that respiratory drive decreases gradually during bicarbonate haemodialysis. The improvements of pulmonary mechanics, rather than the rapid alkalization of body fluids, responds to the decrease of P0.1 in renal failure patients ventilated with PSV.

Aged↗
PubMed1997

Concurrent 5-fluorouracil, leucovorin, etoposide, cisplatin and radiotherapy for locally advanced non-small cell lung cancer.

BACKGROUND: The prognosis of Stage III unresectable non-small cell lung cancer may be improved by concurrent chemoradiotherapy. In this study, we attempted to evaluate the feasibility, tolerance, efficacy and toxicities of the combination of thoracic radiation and chemotherapy with a novel regimen that included 5-fluorouracil, leucovorin, etoposide and cisplatin (the FLEP regimen) in the treatment of this group of patients. PATIENTS AND METHODS: From July 1995 to September 1996, 20 untreated patients with locally advanced non-small cell lung cancer were enrolled in the study. Radiation at a dose of 44 Gy was initially delivered in daily fractions of 2 Gy 5 days a week to the tumor and mediastinum, followed by a boost to the tumor (20 to 26 Gy according to patients tolerance). Concurrently with thoracic irradiation, patients were treated with chemotherapy consisting of cisplatin at the dose of 60 mg/m2/d for 1 day, etoposide at the dose of 60 mg/m2/d for 2 days, and 5-FU 500 mg/m2/d plus leucovorin 50 mg/d infusion for 48 hours. Cycles of chemotherapy were repeated every 3 weeks for a maximum of 3 cycles. RESULTS: Seventeen of 20 patients were assessable. The overall response rate was 70.6% (95% confidence interval = 49-92%). No complete response was achieved. The median response duration for all responding patients is not yet estimable, with a range of 3.5 to 15.5+ months. Eleven patients remain progression-free for 4 to 15 months. The median survival for the entire group is not estimable. The major toxicity was esophagitis. Other grade 3 or 4 toxicities were not frequently observed. CONCLUSION: Combined-modality therapy with FLEP regimen and radiation is a promising treatment with a high response rate and acceptable toxicity for locally advanced non-small cell lung cancer.

Adult↗
PubMed1996

Effect of beta 2-adrenoceptor agonists on plasma potassium and cardiopulmonary responses on exercise in patients with chronic obstructive pulmonary disease.

OBJECTIVE: The effect of beta 2-adrenoceptor agonist-induced hypokalaemia on cardiac arrhythmias might be exacerbated during exercise, especially in patients with more compromised airway function. METHODS: To evaluate the effect of beta 2-adrenoceptor agonists on plasma potassium and cardiopulmonary function during exercise, two identical submaximal treadmill exercise tests were performed, at least 48 h apart, by 13 patients with moderate to severe COPD (11 men and 2 women, mean age 66 y, mean FEV1/FVC ratio 48.9 (2.8)% 30 min after they had received nebulised fenoterol or salbutamol (2 mg). The experiment was done as a randomised, double-blind, crossover trial after an initial baseline study with vehicle (0.45% saline). Plasma potassium concentration, spirometry and the degree of breathlessness (Borg scale) were measured before treatment and immediately after exercise; oxygen saturation, QTc interval and cardiac rhythm were monitored continuously before, during and for 30 min after exercise. RESULTS: After the saline control, exercise caused an increase in Borg rating (of 4.9), a premature ventricular contractions (VPC) (2.8 beats/min), and a fall in oxygen saturation (-6.7%), but no significant change in plasma potassium (+0.04 mEq.dl-1), FEV1 or QTc interval. Inhalation of fenoterol and salbutamol did not affect QTc interval, Borg scale or VPC frequency at rest, but significantly increased the duration of exercise undertaken to reach the submaximal levels (786 s, versus 783 s) compared to the vehicle control. Following exercise, plasma potassium fell after fenoterol by 0.2 mEq.dl-1 and it increased after salbutamol by 0.1 mEq.dl-1 compared to baseline levels. Plasma potassium after exercise was significantly lower after fenoterol (3.2 mEq.dl-1) compared to the saline control (3.7 mEq.dl-1) and salbutamol (3.6 mEq.dl-1). Neither fenoterol nor salbutamol had any significant effect on the change in FEV1, oxygen saturation, Borg scale, frequency of VPCs or QTc interval during or after exercise compared to the saline control. CONCLUSION: When compared to salbutamol 2 mg, fenoterol 2 mg caused more marked hypokalaemia but no significant difference in cardiopulmonary response in patients with COPD during exercise.

Adrenergic beta-Agonists↗
PubMed1996

Differential effects of nasal continuous positive airway pressure on reversible or fixed upper and lower airway obstruction.

Our study was to assess whether there were differential effects of nasal continuous positive airway pressure (nCPAP) on different kinds of obstruction in either upper or lower airways in patients with chronic obstructive pulmonary disease (COPD). nCPAP (6 cmH2O for ten minutes) was applied to 7 patients with reversible extrathoracic upper airway obstruction (RUAO) and 3 patients with fixed extrathoracic upper airway obstruction (FUAO). Eighteen stable asthmatics, receiving methacholine challenge to induce a more than 20% reduction in FEV1, were randomly investigated for the effect of nCPAP or sham pressure on reversible lower airway obstruction. Nine stable COPD patients were enrolled to study the effect on irreversible lower airway obstruction. Maximal expiratory and inspiratory flow volume curves and dyspnoea scores were obtained before and after immediate withdrawal of nCPAP. In the RUAO group, nCPAP significantly improved stridor and dyspnoea scores, decreased the ratio of FEF50/FIF50 from 2.05 +/- 0.25 to 1.42 +/- 0.16, and increased peak inspiratory flow (PIF) as well as forced inspiratory vital capacity by 26 +/- 8% and 9 +/- 4%, respectively. In expiratory phase, there was no significant change in pulmonary functions. In asthmatics, nCPAP significantly reversed methacholine-induced bronchoconstriction increasing forced vital capacity by 10 +/- 3%, FEV1 by 15 +/- 4% and PIF by 32 +/- 11%. nCPAP significantly increased the response to bronchodilators. The improvement in airflow rate persisted for at least 5 min after nCPAP withdrawal and was highly correlated with the response to bronchodilators. There was no significant effect of nCPAP on airflow rate in COPD patients. Subjective dyspnoea score changes paralleled the pulmonary function improvement. We conclude that there are differential effects of nCPAP on airflow rates in patients with different nature of airway obstruction. Patients with airway obstruction caused by structural changes may not benefit from the use of nCPAP in improving airflow rates.

Adolescent↗
PubMed1996

[Community-based integrated home care model for the demented patients and their families].

The purposes of this research project were to establish an integrated home care model and understand the influence of an integrated home care model on demented elders and their families. The changes in cognitive function and self-care ability of demented elders were also explored longitudinally. The disciplines involved in the integrated home care model included doctors, home care nurses and social workers. The integrated home care model was developed according to the functions and roles of different disciplines in their actual working process. Services provided included home nursing care, telephone consultation and a support group. Home care nurses played the role of case manager in this model. Twenty-five families participated in this study. Among them, 22 received home care service, and 20 of them participated in a caregiver support group. The cognitive function of the demented elders did not significantly decrease over the 6-month period. Among their self-care ability, grooming and eating dependency were found significantly increased during this period. Overall, 81% families reported that home nursing care services could help them to develop care skills, care knowledge and provided emotional support. However, the caregiver burden did not significantly decrease after the home nursing care services. Seventy percent of caregivers reported that telephone consultation could support them emotionally and provided them with information concerning care. Over half of the caregivers reported that in getting related information and receiving emotional support was helpful. This integrated model developed from this research project can be adapted and used in networking home care agencies, the community and health care resources. The small and convenient sample was one of the limitations of this study. The insignificance of some of the findings might be due to the short time period (6 months) and some effects of the model might appear later than 6 months. For further research, larger and random samples and a longer period of follow-up with more health disciplines involved were suggested.

Aged↗
PubMed1995

Effect of nasal continuous positive airway pressure on methacholine-induced bronchoconstriction.

Bronchial hyper-responsiveness is a cardinal feature of asthma. To determine whether nasal continuous positive airway pressure (NCPAP) influences airway smooth muscle in response to exogenous stimuli, we examined the effect of NCPAP on aerosolized methacholine-induced bronchoconstriction in 16 stable asthmatic patients. The dose-response curve for each subject was measured by a log transformation and linear regression analysis as well as a formula fitted to the data points to obtain values for a (slope) and b (position). The PD20FEV1 significantly increased in patients receiving 8 cmH2O of NCPAP by one doubling dose compared with that in patients using sham pressure. NCPAP shifted the dose-response curves to be flatter, deviated upwards and to the right. The coefficient a, indicating bronchial reactivity, was significantly lower in patients receiving NCPAP. The coefficient b, indicating the bronchial sensitive threshold, was higher after applying NCPAP. In contrast, coefficients a and b did not change in subjects with sham pressure. NCPAP also significantly enhanced the bronchodilator effect of inhaled salbutamol in response to methacholine-induced bronchoconstriction. In summary, we have shown that NCPAP therapy improves bronchial smooth reactivity with an increase in PD20FEV1 and a reduction in the bronchial reactivity and bronchial sensitivity. Therefore, NCPAP may provide an adjuvant therapy in patients with acute bronchial asthma.

Acute Disease↗
PubMed1994

Bilateral hepatic duct decompression via a single percutaneous tract using a 'mother-baby' drainage catheter.

Decompression of the right and left hepatic ducts using a 'mother-baby' self-made drainage system via a single percutaneous tract was performed successfully in 15 of 21 patients with benign (n = 4) and malignant (= 17) hilar obstruction. The 'mother-baby' drainage system was composed of an 18 F catheter placed through the right hepatic duct into the distal common bile duct which was designated as the 'mother' catheter, while a second 10 F baby catheter was placed through the first catheter into the left hepatic ducts. This was achieved by a three-stage procedure: (1) percutaneous transhepatic biliary drainage; (2) balloon dilatation of the tract; and (3) intubation of the contralateral hepatic duct and placement of the 'mother-baby' drainage catheters. The mean interval of stent clogging was 5 months, with a range of 2-9 months. In 12 malignant cases, average survival time was 9.8 months. The technique avoided a second percutaneous hepatic puncture in centrally obstructing lesions and afforded bilateral biliary decompression.

Aged↗
PubMed1993

Percutaneous choledochoscopic biliary tract stone removal: experience in 645 consecutive patients.

Our experience in non-operative retrieval of biliary tract stones through PTCS (percutaneous transhepatic cholangioscopy, n = 103) and POC (post-operative choledochoscopy, n = 542) plus the use of Dormia basket and EHL (electrohydraulic lithotripsy) is presented. The results of transhepatic and T-tube routes are compared, with emphasis on the technical difficulties encountered. The success rates were 96% and 97% in POC and PTCS, respectively. No mortality was related to these procedures. Intrahepatic duct angulation and stricture were the factors most often responsible for failure. Postoperative choledochoscopic stone removal is safe and the method of choice for retained biliary tract calculi, while PTCS is highly indicated for those high-risk patients with or without previous biliary surgery. POC and PTCS have, therefore, their own indications and differ in their clinical applications.

Adult↗
PubMed1992

Exploration of factors related to direct care and outcomes of caregiving. Caregivers of terminally ill older persons.

The purpose of this study was to explore factors related to the amount of direct care and outcomes of caregiving experienced by family members of terminally ill older persons using secondary analysis. A total of 55 caregivers whose care receivers were aged greater than or equal to 65 years were selected from Kirschling's (1988) hospice sample. The majority of caregivers were female (75%) and the spouse of the care receiver (66%). The duration of caregiving ranged from 1 to 180 months. Most care receivers were diagnosed with cancer (84%) and had been ill for 2-360 months (mean = 30.2). The mean length of time in hospice for care receivers was 2.4 months. Caregivers most frequently provided little extra tasks that were least difficult, least upsetting, and easier to provide. Behavioral problem tasks were least frequently provided but were reported as the most difficult, tiring, upsetting, and hardest to provide. Caregivers whose care receivers had been in hospice for greater than 34 days reported having to provide more communication tasks than caregivers whose ill older family members had been in hospice less than 34 days. Long-term caregivers (providing care for greater than 9 months) whose care receivers had been in hospice for greater than 34 days provided significantly fewer personal care tasks than short-term caregivers. Finally, there were no significant effects for duration of caregiving and length of time in hospice on outcomes of caregiving.

Adult↗
PubMed1992

Therapeutic embolization of post-cholecystectomy hepatic artery aneurysm.

A "sandwich" technique employing steel coils and gelfoam embolization was applied in two cases of hepatic artery aneurysms. Immediate cessation of the bleeding was evident clinically and the post-embolization angiogram showed occlusion of the vascular lesion. Cholecystectomy is one of the most common abdominal operations and it is generally well tolerated, particularly in young and middle-aged patients. Morbidity rates of 5% to 32% and mortality rates of 0.4% to 2.5% have been reported, depending on such factors as age, underlying illness, etc. (1-4). The most frequent complications of cholecystectomy are wound infection, abscess, ductal injury or ligation, and bleeding. This paper describes two cases of hepatic pseudoaneurysm following iatrogenic damage during cholecystectomy which was treated with transarterial embolization.

Aneurysm↗
PubMed1989

The morphology of cat spinal neurons projecting to both the lateral cervical nucleus and the dorsal column nuclei.

Morphological features of physiologically characterized doubly projecting spinocervical tract-dorsal column postsynaptic (SCT-DCPS) neurons were examined following intracellular injections of horseradish peroxidase. Their cell bodies and majority of dendrites were located in laminae III-IV. The SCT-DCPS neurons have rostrocaudally elongated dendritic trees with spiny fine caliber dendrites, and issue local axon collaterals that are studded with varicosities. The results show that the doubly projecting SCT-DCPS neurons do not represent a morphologically distinct subset of the spinocervical tract (SCT) or dorsal column postsynaptic (DCPS) cells.

Animals↗
PubMed1983

Interferon activity produced by interferon messenger RNA in Tilapiamosaiabica peters oocytes.

The activities of interferon mRNA from various types of mouse cells have been studied using Tilapiamosaiabica peters oocytes (TPO) as the translation system. The translation activity of interferon mRNA in TPO was also compared with that in Xenopus laevis oocytes (XLO). The results obtained showed similar translation efficiency in both systems. The highest translation efficiency was observed when T. peters oocytes, microinjected with mRNA, were cultivated in Eagle's medium containing 0.01% HEPES and 0.5% NaHCO3 (pH 7.5) at 25 degrees C. pppA2' P5' A2' P5' A in concentration of 500 nM did not affect the translation of interferon mRNA in oocytes, but inhibition was demonstrated at 1 microM. A linear relationship was found between the amount of interferon mRNA injected and the antiviral activity of the translation products, suggesting that the amount of interferon mRNA can be determined by assaying the interferon activity of its translation product.

Adenine Nucleotides↗
PubMed1971

Differentiable pseudo-free circle actions.

The circle group G is said to act pseudofreely if it is not free and if every orbit is one-dimensional and if the isotropy group is the identity except on isolated exceptional orbits where the isotropy group is the finite cyclic group Z(k), k > 1. We consider differentiable actions of this kind on homotopy seven spheres and classify all such actions. As a corollary, it follows that there can be any finite number of exceptional orbits, in contrast to the linear case where there can be at most four.

Journal Article↗