Search PubMed⌕ Search

Biomedical subjects

C Chin

Publications and source records attributed to C Chin.

At least 37 records · Page 2Linked to original sources
PubMed2000

Health status, perceptions of coping, and social support immediately after discharge of survivors of acute myocardial infarction.

BACKGROUND: The period immediately after discharge from the hospital after an acute myocardial infarction is a stressful and vulnerable time about which little is known. OBJECTIVE: To explore health status, perceptions of coping, and social support among survivors of a recent myocardial infarction in the first 3 weeks after discharge from hospitals in southwestern Sydney, Australia. METHODS: A descriptive, exploratory approach with a triangulated methodology was used to assess the experiences of 38 survivors, detect patterns in these experiences, explore the health-support needs of survivors, and determine changes in health status in the first 3 weeks after discharge. Quantitative data were collected with the Medical Outcomes Study SF-36, New York Heart Association classification, Canadian Cardiovascular Society Angina Scale, and the Jalowiec Coping Scale. A semistructured interview schedule provided additional qualitative data about the experiences of the survivors. RESULTS: The health status of participants was relatively stable during the 3-week period; most had no activity limitation due to dyspnea or angina. However, the subjects' health status was considerably lower than that of their age-matched population. The most common and most effective coping strategies adopted during this period were confrontation, optimism, and self-reliance. In addition, the subjects experienced anxiety, depression, ambiguity and uncertainty, fear of recurrence of the infarction and of deterioration in health, of boredom and of inertia. CONCLUSION: These findings can help nurses in hospital and community settings assist survivors of acute myocardial infarction to prepare for and deal effectively with experiences during convalescence.

Adaptation, Psychological↗
PubMed1999

alpha(1L)-adrenoceptors mediate noradrenaline-induced contractions of the guinea-pig prostate stroma.

The alpha(1)-adrenoceptor subtype mediating noradrenaline-induced contractions of the guinea-pig isolated prostatic smooth muscle was investigated. Noradrenaline produced concentration-dependent contractions of the tissue with a mean pD(2) value of 5.26+/-0.03 (n=20). These contractions were antagonised by prazosin, 2-(2, 6-dimethoxyphenoxyethyl)aminomethyl-1,4-benzodioxane hydrochloride (WB-4101), N-[2-(2-cyclopropylmethoxyphenoxy)ethyl]-5-chloro-alpha, alpha-dimethyl-1H-indole-3-ethanamine hydrochloride (RS-17053) and (R)-5-[2-[[2-(2-ethoxyphenoxy)ethyl]amino]-2-methylethyl]-2- methoxybenzensulfonamide methanesulphonate hydrate (tamsulosin). Mean pA(2) or apparent pK(B) estimates for the antagonism of noradrenaline were 8.15+/-0.05 for prazosin; 8.83+/-0.11 for WB-4101, 7.18+/-0.14 for RS-17053 and 10.11+/-0.12 for tamsulosin. The relatively low estimates of the apparent dissociation constant for all antagonists except tamsulosin indicate that an alpha(1L)-adrenoceptor mediates noradrenaline-induced prostatic smooth muscle contraction in the guinea-pig prostate gland.

Adrenergic alpha-1 Receptor Agonists↗
PubMed1999

Acute lung injury after tracheal instillation of acidified soya-based or Enfalac formula or human breast milk in rabbits.

PURPOSE: The aim of this study was to compare the severity of the acute lung injury after tracheal instillation of acidified soya-based or Enfalac infant formula, or human breast milk (HBM) in anesthetized rabbits. METHODS: Alveolar-arterial oxygen tension gradient (A-aDO2) and dynamic compliance were measured before (baseline) and hourly for four hours after tracheal instillation of 0.8 ml x kg(-1) soya-based or Enfalac infant formula or HBM (all acidified to pH 1.8 with hydrochloric acid) or no fluid (control) in 24 anesthetized and tracheotomized adult rabbits. The A-aDO2, the difference between alveolar and arterial oxygen tensions, was corrected for barometric pressure and carbon dioxide tension. Dynamic compliance was the ratio of the expired tidal volume to the peak inspiratory airway pressure, normalized to body weight. RESULTS: Baseline A-aDO2 and dynamic compliance were similar among the four groups. In the control rabbits, A-aDO2 remained unchanged throughout the four hours, whereas mean A-aDO2 increased 180 mm Hg in the soya-based group (P < 0.0025) and 350 and 275 mm Hg in the Enfalac and HBM groups respectively (P < 0.0002). The order of the A-aDO2 post-instillation was Enfalac approximately/= HBM > soya > control (P < 0.0002). Dynamic compliance decreased 10-12% in the control rabbits during the four post-instillation measurements compared with baseline (P < 0.033), decreased 20% in the soya-based group (P < 0.0002) and 40-50% in the Enfalac and HBM groups (P < 0.0002). CONCLUSION: The severity of the acute lung injury after intratracheal instillation of infant feeds in a volume of 0.8 ml x kg(-1) and at pH 1.8 in rabbits depends in part, on the type of feed: Enfalac approximately/= HBM > soya > control.

Animals↗
PubMed1999

Brachial artery reactivity: A modified technique with applicability to children.

Brachial artery reactivity noninvasively tests endothelial function. Cuff pressures of 180 to 300 mm Hg have been used. These pressures are ill advised in neonatal and premature infants. We therefore evaluated the use of substantially lower occlusive pressures. Fifteen adult subjects were enrolled. One arm was occluded to 200 mm Hg, and the other arm was occluded to 40 mm Hg above the resting systolic pressure. The occlusion time was 4.5 minutes. The brachial artery was measured at baseline and 1 minute after cuff deflation. Low pressure occlusions averaged 155.7 +/- 7.8 mm Hg versus 200 mm Hg for high pressure occlusions (P <.0001). One of 15 patients with low pressure occlusions reported discomfort versus 7 of 15 with high pressure occlusions (P <.05). Brachial artery reactivity increased by 8.0% +/- 2.5% with low pressure occlusions versus 7.5% +/- 2.7% with high pressure occlusions (P = not significant). Brachial artery reactivity can be assessed at lower occlusive pressures. This may extend the applicability of the technique to children and neonates.

Adult↗
PubMed1999

Duration of preoperative amiodarone treatment may be associated with postoperative hospital mortality in patients undergoing heart transplantation.

OBJECTIVE: To assess the effect of preoperative amiodarone treatment on patient mortality after heart transplantation. DESIGN: Retrospective study. SETTING: Single-institution university hospital. PARTICIPANTS: One hundred six consecutive patients with heart transplants. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Patients were grouped according to duration of preoperative amiodarone treatment, and posttransplant mortality before hospital discharge was compared with patients not treated with amiodarone. The authors collected cardiovascular data in the preoperative and postoperative periods. There was a significant increase in posttransplant mortality before hospital discharge in patients treated with amiodarone for more than 4 weeks in the preoperative period (p < 0.05). Patients treated with amiodarone had significantly lower (p < 0.05) heart rates (mean heart rate, 103+/-19 beats/min) in the early postoperative period than patients not treated with amiodarone (mean heart rate, 111+/-15 beats/min), but there was no relationship with mortality (p = not significant). Patients who died had a significantly lower (p < 0.05) postoperative cardiac index (2.2+/-0.7 to 2.5+/-0.7) in the first 24 hours after cardiopulmonary bypass compared with patients who survived to hospital discharge (3.0+/-0.7 to 3.1+/-0.9), but there was no relationship to amiodarone treatment (p = not significant). CONCLUSION: Preoperative amiodarone treatment for more than 4 weeks may be associated with a significant increase in postoperative mortality in patients undergoing heart transplantation. Therefore, the indications for amiodarone must be carefully considered and, if needed, the maintenance dose should be kept to a minimum.

Amiodarone↗
PubMed1999

QT dispersion predicts ventricular arrhythmia in pediatric cardiomyopathy patients referred for heart transplantation.

BACKGROUND: QT dispersion has been used in stratifying risk for sudden death in adults with dilated cardiomyopathy, but its role in the pediatric population has not been delineated. METHODS: We reviewed electrocardiograms in pediatric patients with dilated cardiomyopathy referred for heart transplantation, to evaluate the role of QT dispersion in predicting malignant arrhythmias in these patients. Three groups were defined: Group I (n = 13) had dilated cardiomyopathy and malignant ventricular arrhythmias, Group II (n = 13) had dilated cardiomyopathy with no ventricular arrhythmias and Group III (n = 30) consisted of normals. QT dispersion was defined as the duration of the shortest QT subtracted from that of the longest. In addition, the standard deviation of the QT intervals was calculated for each ECG, using 12 leads. RESULTS: QT dispersion was significantly prolonged in Group I (97 +/- 33 msec) compared to Group II (74 +/- 19 msec) and Group III (42 +/- 17 msec). QT standard deviation was also prolonged in Group I (30 +/- 11 msec) vs Group II (22 +/- 5 msec) and Group III (13 +/- 4 msec). Using a threshold value of 90 msec for QT dispersion or 25 msec for QT standard deviation, a sensitivity of 78% and a specificity of 70% was obtained for identifying patients who would subsequently develop ventricular arrhythmias. CONCLUSIONS: In pediatric heart transplant candidates with dilated cardiomyopathy, QT dispersion and QT standard deviation identify patients at higher risk for the development of malignant ventricular arrhythmia. This simple test can be helpful in the evaluation and management of these patients awaiting transplantation.

Adolescent↗
PubMed1999

The use of advanced-age donor hearts adversely affects survival in pediatric heart transplantation.

There is a limited supply of adequate donor hearts for cardiac transplantation. The safety of using advanced-age donor hearts has been debated in adult transplantation but has not been studied previously in pediatric recipients. In this retrospective study, survival of 79 pediatric heart transplant recipients was reviewed. Pediatric recipient groups were stratified based on donor age (group 1 donor age > 40 yr, n = 5; group 2 donor age < or = 40 yr, n = 74). Survival of 267 adolescent (ages 11-17) heart transplant recipients in the United Network for Organ Sharing (UNOS) database was also reviewed. Patients were likewise divided into two groups based on donor age (> 40 yr, n = 12; < or = 40 yr, n = 255). Survival at one yr was 20% in group 1 vs. 78% in group 2 (p < 0.005). Cause of death in all group 1 patients was graft failure secondary to acute rejection. Analysis of risk of death was only significantly attributable to the age of the donor. The increased risk attributable to advanced donor age was also supported by the UNOS data. The UNOS one and two-year Kaplan-Meier survival curves were significantly lower in adolescent patients who received donor hearts > 40 yr of age. One-year survival was 58% (older donors) vs. 85% (younger donors, p < 0.005) and two-year survival was 44% (older donors) vs. 79% (younger donors, p < 0.005). Advanced-age donor hearts should be contraindicated in pediatric transplantation with the exception of critically ill patients who may not be able to wait for a younger heart.

Acute Disease↗
PubMed1999

Involvement of the carboxyl terminus of the third intracellular loop of the cannabinoid CB1 receptor in constitutive activation of Gs.

The human cannabinoid receptor CB1 functionally couples primarily to Gi-, but also to Gs-mediated pathways to modulate intracellular cyclic AMP (cAMP) levels. To probe the features of the receptor that may be involved in promoting interactions with one G protein type over another, we generated the L341A/A342L mutant CB1 receptor. The double mutation involved the swap in position of two adjacent residues in the carboxyl-terminal segment of the third intracellular loop of CB1. This resulted in partial constitutive activation of the receptor and an agonist-independent enhancement in cAMP levels. Characterization following treatment with either pertussis or cholera toxin indicated that the constitutive activity is selective for a Gs- and not a Gi-mediated pathway. Treatment with the CB1-specific inverse agonist SR141716A inhibited the basal accumulation of cAMP in the presence of pertussis toxin, establishing that the effect is CB1 mediated. The binding of the agonist CP-55,940 to the L341A/A342L receptor was not markedly different from that for the wild-type receptor despite the constitutive Gs activity. This may reflect a preference of this ligand for an activated receptor state associated with the Gi coupling form and underscores the potential for developing therapeutics that selectively activate one pathway over another.

Animals↗
PubMed1999

Acute lung injury after instillation of human breast milk into rabbits' lungs: effects of pH and gastric juice.

BACKGROUND: The authors compared the lung injury in rabbits that occurred after tracheal instillation of human breast milk (HBM) acidified to pH 1.8 with hydrochloric acid (HCl), HBM at its native pH (7.0), and HBM acidified with gastric juice to pH 1.8 and 3.0. METHODS: The alveolar-to-arterial oxygen tension gradient and dynamic compliance were recorded before and hourly for 4 h after intratracheal instillation of 0.8 ml/kg HBM acidified with HCI (pH 1.8), HBM at its native pH (7.0), HBM acidified with gastric juice (pH 1.8 or 3.0), or 5% dextrose solution acidified with gastric juice (pH 1.8) as a control in 30 adult rabbits. The circulating neutrophil count and phagocyte oxidant activity were determined before and 1 and 4 h after instillation. RESULTS: The alveolar-to-arterial oxygen tension gradient increased and dynamic compliance decreased significantly in all groups after instillation of HBM compared with baseline values and those in the control group. The severity of the lung injury after instillation of HBM at all pH values (1.8, 3.0, and 7.0) and after acidification with gastric juice or HCl was similar. The circulating neutrophil count increased steadily for 4 h after instillation (P < 0.013), whereas spontaneous phagocyte oxidant burst activity peaked at 1 h (P < 0.007) and returned to baseline by 4 h after instillation. CONCLUSIONS: The severity of the lung injury after tracheal instillation of 0.8 ml/kg HBM in rabbits is similar at pH values between 1.8 and 7.0 after acidification with HCl or gastric juice. Tracheal instillation of HBM increases the circulating neutrophil count and phagocyte oxidant burst activity.

Animals↗
PubMed1999

Isolation of Japanese encephalitis virus from mosquitoes collected in Northern Taiwan between 1995 and 1996.

Mosquito collections were carried out from May to October in 1995 and 1996 at Yingko and Sanhsia of Taipei County and Chunan of Miaoli County. A grand total of 13,576 mosquitoes consisting of 13 species in 407 pools were processed and inoculated into Aedes albopictus clone C6/36 cell cultures. One hundred thirty seven pools of these showed the presence of viral antigens in the infected C6/36 cell lysates which were identified by the indirect fluorescent antibody test using a monoclonal antibody against Japanese encephalitis (JE) virus. The postive pools, were divided into 97, 20, 1, 8, 1, 1, 7, and 2 pools from Culex tritaeniorhynchus Giles, Aedes albopictus Skuse, Aedes vexans nocturnus (Theobald), Armigeres subalbatus (Coquillett), Culex annulus Theobald, Culex fuscanus Wiedemann, Culex quinquefasciatus Say, and Culex sitiens Wiedemann respectively. The dominant species collected at night was Culex tritaeniorhynchus, while Aedes albopictus was the dominant species collected in daytime. Besides the pigpens, avian habitats are also a dominate source of JE virus in this study.

Animals↗
PubMed1999

Antibody responses to an immunodominant nonstructural 1 synthetic peptide in patients with dengue fever and dengue hemorrhagic fever.

Two flaviviruses, dengue (DEN) virus and Japanese encephalitis (JE) virus, are important because of their global distribution and the frequency of epidemics in tropical and subtropical areas. To study the B-cell epitopes of nonstructural 1 (NS1) glycoprotein and anti-NS1 antibody response in DEN infection, a series of 15-mer synthetic peptides from the predicted B-cell linear epitopes of DEN-2 NS1 protein were prepared. Enzyme-linked immunosorbent assay (ELISA) was performed to analyze antibody responses to these peptides from sera of both DEN and JE patients. One peptide derived from DEN-2 NS1, D2 NS1-P1 (amino acids 1-15), was identified as the immunodominant epitope that reacted with sera from dengue fever (DF) patients but not JE patients. The isotype of D2 NS1-P1-specific antibodies was mainly immunoglobulin M (IgM) in all sera that tested positive. A specificity study demonstrated that sera from all four DEN types reacted with D2 NS1-P1. A dynamics study showed that specific antibodies to this peptide could be detected as early as 2 days after the onset of symptoms. We observed significant anti-D2 NS1-P1 antibody responses in 45% of patients with primary and secondary infections with DF or with dengue hemorrhagic fever. This is the first report demonstrating that significant anti-DEN NS1 antibodies can be induced in the sera of patients with primary DEN infection.

Amino Acid Sequence↗
PubMed1998

Gastric emptying after pylorus-preserving gastrectomy in comparison with conventional subtotal gastrectomy for early gastric carcinoma.

It is well known that surgical intervention on the stomach will greatly alter gastric function and gastric emptying. In this study, we evaluated the difference in postoperative gastric remnant emptying following pylorus-preserving gastrectomy (PPG) and conventional subtotal gastrectomy (CDG) using sulfamethizole capsule food. The subjects comprised 18 patients who underwent PPG and 23 who underwent CDG for early gastric carcinoma. While delayed gastric emptying was observed early after PPG, 1 year after PPG it was markedly accelerated compared with that measured in the early postoperative period. However, it was slower than that in the CDG patients. On the other hand, rapid gastric emptying was observed early after CDG and did not change with time. These findings stress that although PPG results in stasis in the early postoperative period, it seems to prevent unduly rapid emptying.

Anti-Infective Agents↗
PubMed1998

A new therapeutic approach to the fetus with congenital complete heart block: preemptive, targeted therapy with dexamethasone.

BACKGROUND: Therapy of established congenital complete heart block in the fetus has resulted in improved survival but persistence of heart block. This exposes the infant to the morbidity of heart block, including the risk of sudden death and pacemaker implantation. CASE: A 35-year-old gravida 2, para 1, with Sjogren syndrome and a previous pregnancy complicated by congenital complete heart block presented during her second pregnancy. Intensive fetal monitoring with echocardiography was employed. Early evidence of myocardial dysfunction and dysrhythmia was found, dexamethasone therapy was initiated, and the dysfunction and dysrhythmia resolved. The pregnancy went to term without further complication. CONCLUSION: This represents a new and successful strategy to identify very early signs of myocardial disease in a fetus at high risk of congenital complete heart block, enabling targeted, preemptive therapy.

Adult↗
PubMed1998

Intravenous diltiazem in acute myocardial infarction. Diltiazem as adjunctive therapy to activase (DATA) trial.

OBJECTIVES: This study was defined as a pilot investigation of the usefulness and safety of intravenous diltiazem as adjunctive therapy to tissue plasminogen activator in acute myocardial infarction, followed by oral therapy for 4 weeks. BACKGROUND: Experimental studies have documented that calcium antagonists protect the myocardial cell against the damage caused by coronary artery occlusion and reperfusion, yet no benefits have been conclusively demonstrated in acute myocardial infarction (AMI) in humans. METHODS: In this pilot study, 59 patients with an AMI treated with tissue-type plasminogen activator (t-PA) were randomized, double blinded, to intravenous diltiazem or placebo for 48 h, followed by oral therapy for 4 weeks. The primary objective was to detect an effect on indices of regional left ventricular function and perfusion. Patients were also closely monitored for clinical events, coronary artery patency and indices of infarct size and of left ventricular function. RESULTS: Creatine kinase elevation, Q wave score, global and regional left ventricular function and coronary artery patency at 48 h were not significantly different between the diltiazem and placebo groups. A greater improvement observed in regional perfusion and function with diltiazem was likely explained by initial larger defects. Diltiazem, compared to placebo, reduced the rate of death, reinfarction or recurrent ischemia at 35 days from 41% to 13% (p=0.027) and prevented the need for an urgent intervention. The rate of death or myocardial infarction was reduced by 65% (p=0.15). These benefits could not be explained by differences in baseline characteristics such as age, site and extent of infarction, time of inclusion or concomitant therapy. Heart rate and blood pressure were reduced throughout the study with active diltiazem treatment. Side effects of diltiazem were bradycardia and hypotension that required transient or permanent discontinuation of the study drug in 27% of patients, vs. 17% of patients with placebo. CONCLUSIONS: A protective effect for clinical events related to early postinfarction ischemia and reinfarction was suggested in this study, with diltiazem administered intravenously with t-PA followed by oral therapy for 1 month, with no effect on coronary artery patency and left ventricular function and perfusion.

Administration, Oral↗
PubMed1998

Effects of altering the time of administration and the time frame of quality of life assessments in clinical trials: an example using the EORTC QLQ-C30 in a large anti-emetic trial.

Previous studies conducted by our group suggested that the ability to demonstrate an impact of emesis control on quality of life might depend upon when an quality of life instrument was administered in relation to chemotherapy and on the time frame of the questionnaire. This study was conducted to address this issue. Six hundred and fifty patients receiving moderately emetogenic chemotherapy in a randomized trial comparing a variety of anti-emetic regimens were allocated to four different modes of administration (days 4 and 8; 3 and 7 day time frames) of the QLQ-C30. Patients who completed the questionnaire at the time of maximal impact of chemotherapy (day 3) were more likely to report deterioration in quality of life. Patients who completed questionnaires at day 8 were more likely to report deterioration in quality of life if their questionnaire had a 7 day time frame rather than a 3 day time frame. Patients receiving more effective anti-emetic therapy had better quality of life. It was concluded that better anti-emetic control improves quality of life after moderately emetogenic chemotherapy. In studying quality of life in situations where the impact of treatment waxes and wanes, careful attention needs to be paid to scheduling the administration of questionnaires and to their time frame.

Adult↗
PubMed1998

Exercise-induced decreases in sarcoplasmic reticulum Ca(2+)-ATPase activity attenuated by high-resistance training.

Muscle biopsies were performed on the vastus lateralis muscle prior to and during a high-resistance training (HRT) programme in order to examine the effects of hypertrophy on sarcoplasmic reticulum Ca2+ ATPase activity at rest and during exercise. In six male untrained volunteers (peak aerobic power, Vo2 peak = 3.39 +/- 0.13 L min-1, mean +/- SE), the resting Ca2+ ATPase activity (mumol-min-1 g wet wt-1) at 0 (4.89 +/- 0.20), 4 (5.62 +/- 0.56), 7 (5.15 +/- 0.41) and 12 (4.82 +/- 0.11) weeks was unchanged by HRT. During cycle ergometer exercise, prior to training, Ca(2+)-ATPase was reduced (P < 0.05) by 14% during the initial 30 min at 58% Vo2 peak and (P < 0.05) a further 19% during 30 min at 72% Vo2 peak. Following 7 and 12 weeks of training, the decreases in SR Ca(2+)-ATPase were less pronounced (P < 0.05). These results indicate that muscle hypertrophy, although incapable of altering Ca(2+)-ATPase pump activity at rest, can attenuate the decrease observed in exercise by mechanism(s) as yet unknown.

Adult↗
PubMed1998

The experiences of female spouses of survivors of acute myocardial infarction: a pilot study of Lebanese-born women in south-western Sydney, Australia.

Lebanese migrants form a significant proportion of the population in southwestern Sydney (SWS), and in New South Wales, Australia. This pilot study was undertaken in south-western Sydney, a rapidly expanding and socioeconomically disadvantaged region, to explore the experiences of English speaking women of Lebanese origin whose spouses had recently experienced an acute myocardial infarction (AMI). Semi-structured interviews were conducted with seven Lebanese-born women at 2- and 4-week intervals, following the discharge of their husbands from hospital. Qualitative analysis of narrative text revealed four distinct themes. These were: struggle to resolve distress; intensive monitoring of the AMI survivor; searching for avenues of support; and reflecting on the future. Study findings are discussed in relation to the literature. Implications for nursing practice and research are drawn from study findings.

Adaptation, Psychological↗