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Biomedical subjects

L B Tan

Publications and source records attributed to L B Tan.

At least 55 records · Page 3Linked to original sources
PubMed1994

Inhibition of ACE/kininase-II, acute myocardial infarction, and survival.

Three major trials, in patients with chronic heart failure, have shown that treatment with an ACE inhibitor reduces mortality. However, at the time of writing this review there continue to be strong grounds for uncertainty as to the role of these drugs after acute myocardial infarction in man. This uncertainty is exemplified by the findings of two recently published mortality trials, the CONSENSUS II and the SAVE investigations. Despite virtually identical premises, though widely differing therapeutic approaches, the observations reported in these two papers contrast markedly. In this review we have sought to analyse the possible reasons why the findings of the two trials differ. In our attempt to understand this important issue we have necessarily turned to smaller clinical studies, and also to investigations performed in animals. Furthermore, we review the investigational strategies which have been employed by other, currently unreported, large scale survival studies, as these will certainly hold many of the answers to the questions which the SAVE and CONSENSUS II trials have raised.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1994

Coronary angioplasty in high risk patients with percutaneous cardiopulmonary support.

Cardiopulmonary Support (CPS) was employed electively in 13 patients during high risk percutaneous transluminal coronary angioplasty (PTCA) in accordance with a selection criteria, which included at least two of the following; (i) left ventricular ejection fraction of less than 35%, (ii) target vessel(s) supplying more than 50% of the viable myocardium, and (iii) patients refused coronary bypass surgery. The mean age of the patients was 56.8 +/- 10.7 years (range 39-77). PTCA was attempted in a total of 35 lesions in 12 patients; 29 lesions were successfully dilated (technical success rate of 82.9%). On average, 2.7 lesions were attempted in each patient, and 2.2 lesions were successfully dilated per patient. In one patient the procedure was abandoned due to dissection of the iliac artery during cannulation. One patient died of a large pulmonary embolism 72 h after the procedure. All the surviving 11 patients who had successful PTCA on CPS showed symptomatic improvement during a mean follow-up period of 18.5 +/- 4.3 months (range 11 to 24 months). The commonest complication encountered following the CPS-assisted PTCA was local haematoma (nine of 13 patients), but all patients required transfusion due to significant periprocedural blood loss. Our early experience suggests that CPS enhances the safety of undertaking PTCA in high risk patients.

Adult↗
PubMed1994

Cardiac remodelling.

Explore the source record for details and available documents.

Adaptation, Physiological↗
PubMed1994

[Testis yolk sec tumor--a case report].

A 16-months old normal boy, a right testicular mass was discovered incidentally by his grandmother. Right inguinal orchiectomy was performed. Histological examination showed yolk sac tumor of testis. A preoperative alpha-fetoprotein level was markedly elevated at 13568.9 ng/ml, by the end of the twelve postoperative months, the serum alpha-fetoprotein levels was 118 ng/ml. The patient is doing well one-year postoperatively.

Endodermal Sinus Tumor↗
PubMed1994

Survey of postoperative pain in University Hospital Kuala Lumpur.

One hundred and eighty-three patients undergoing surgery were interviewed twenty-four hours following surgery to assess the quality of pain relief they received in the immediate postoperative period. Interviews were conducted using a standard questionnaire for all patients. They were asked to (1) rate the quality of pain relief they obtained on a Visual Pain Analogue Scale (VPAS-0 being no pain and 10 being the worst imaginable pain); (2) state whether they were happy and satisfied with the pain relief they received; (3) if dissatisfied, they were asked to give their reasons. 37.7% (69 patients) had moderate to severe pain--pain score greater than 6 on the VPAS. Most of these patients had undergone abdominal or major orthopaedic surgery. 32.7% (60 patients) were unhappy with their postoperative pain control. The main reasons for complaint from the patients were that analgesic injections were either not given promptly or were not given at all. The survey also highlighted the inadequate under-administration of narcotic injections in the postoperative period despite orders being written up. It showed there is an urgent need for setting up an Acute Pain Service for better postoperative pain control. An anaesthesiology based Acute Pain Service was started in October 1992.

Adolescent↗
PubMed1993

Biological variation and quality control of plasma human immunodeficiency virus type 1 RNA quantitation by reverse transcriptase polymerase chain reaction.

Quantitation of human immunodeficiency virus type 1 (HIV-1) RNA in the plasma of seropositive individuals was performed by using an external control assay with techniques to standardize and control each measurement. Rigorous study of the variability of the assay showed that the median intraassay reproducibility was log10 0.15 RNA copies per ml of plasma, while the median interassay reproducibility on replicate plasma samples was log10 0.25 copies perml. Specimen stability studies showed reproducible recovery of RNA from plasma stored at -70 degrees C for up to 12 months. In clinically stable patients who were either untreated or taking zidovudine, the average week-to-week variation in plasma RNA levels, measured in real time, was log10 0.30 RNA copies per ml. In contrast, patients either initiating or changing antiretroviral therapy showed a fall of log10 0.8 to log10 2.0 copies per ml in plasma RNA levels. Overall, 105 of 110 (96%) HIV-1-seropositive individuals with CD4 counts of 36 to 868 cells per mm3 had quantifiable HIV-1 RNA over a range of log10 2.70 to log10 6.23 RNA copies per ml, including 81% (13 of 16) of the individuals with greater than 500 CD4 cells per mm3. Accurate and reproducible quantitation of plasma viremia in real time by reverse transcriptase polymerase chain reaction, particularly in asymptomatic HIV-1-infected individuals with high CD4 counts, provides a basis for the use of this virologic measure to monitor the short- and long-term effects of early intervention therapeutic strategies on viral burden.

CD4-Positive T-Lymphocytes↗
PubMed1993

[Complications of transurethral resection of prostate].

A total of 342 benign prostatic hypertrophy patients were treated at the Department of Urology, Kaohsiung Medical College Hospital from January 1972 to December 1988. Median duration of operating time was 74.4 minutes, 67 patients (20%) required a blood transfusion and the mean volume of blood per patient transfused was 1019.4 ml. Median post-operative catheter management was 7 days and the median post-operative ward time was 8.6 days. Two patients (0.5%) had a bladder lesion with peritoneal perforation and required a secondary operation for bladder suture. Secondary hemorrhaging return for treatment of clotting was seen in 11 cases (3.2%). Stress incontinence was noted in 11 cases (3.2%). Anterior urethral stricture was noted in 9 cases (2.6%), impotence occurred in only one case (0.3%) and TUR syndrome in 2 (0.6%). There were two post-operative deaths, for a mortality rate of 0.6 percent. The causes of death were sepsis in one patient and acute renal failure in the other.

Aged↗
PubMed1993

[Foreign body in the urinary bladder].

Foreign bodies in the urinary bladder are not uncommon, however, only a few cases have been reported in recent literature. This is not a fatal disease, however, it may lead to serious complications such as chronic cystitis, urolithiasis, or rectal abscess formation. These foreign bodies were inserted for autoerotic or unknown reasons by patients. In this paper we report 4 cases of foreign bodies in the urinary bladder. They include a cucumber, glass tube, chewing gum, and filliform catheter. We found that most of the foreign bodies in the urinary bladder can be removed endoscopically, but if the patients also had a lower urinary tract obstructive disease, removal necessitated surgical procedures. All of the four cases had no urological complications for at least one year after treatment.

Adult↗
PubMed1993

[Teratoma of testis--a case report].

A case of mature testicular teratoma in a 5-year-old child is presented. The level of serum beta-human chorionic gonadotropin (beta-HCG), alpha-fetoprotein (alpha-AFP), and carcinoembryonic antigen (CEA) were all within normal limit one year post-operatively. We discussed the clinical features, treatment and the result of this patient and reviewed the literature.

Child, Preschool↗
PubMed1992

Cardiac resuscitation with percutaneous cardiopulmonary support.

Percutaneous cardiopulmonary support (CPS) was initiated in 9 patients to provide haemodynamic stability after failure of conventional resuscitation. 4 patients were in cardiogenic shock and 4 remained in asystole, with 1 in resistant ventricular fibrillation, after cardiac arrest. During CPS for those in cardiogenic shock, the mean intra-arterial pressures ranged from 65 to 100 mm Hg (mean 84), at flow rates of between 3 to 5 l/min (mean 3.9). 2 patients underwent technically successful coronary angioplasty. No patient in this group survived. In the cardiac arrest group, acceptable mean intra-arterial blood pressures were achieved (mean 95, range 90-100 mm Hg) at flow rates of between 2 to 3 l/min (mean 2.6). All 5 subjects underwent technically successful coronary angioplasty whilst on CPS. 4 survived. 2 were alive and well at 12 months follow-up, 1 of whom had returned to work; the third is alive and well at 4 months.

Aged↗
PubMed1992

Detection of blood group surface antigens of urinary bladder tumours using monoclonal antibodies with the avidin-biotin complex technique.

We examined 8 normal bladder transitional epithelia and 65 transitional cell carcinomas of the urinary bladder of various stages and grades for the presence of ABO(H) blood group surface isoantigens using the immunoperoxidase staining via the Avidin-Biotin Complex (ABC) methods. It was found that 27% of patients with grade I tumours, 50% with grade II tumours and 82% with grade III tumours had loss of cell surface isoantigens. When correlated with the clinical stage the tumours showed no surface isoantigens in stage D, while 65% of patients with stage A tumours were positive for surface antigens. From among 37 patients (57%), 28 (43%) survived for more than five years. Our results suggest that surface antigens of transitional cell carcinoma of the urinary bladder tended to disappear as the histologic changes of the tumour progressed. It also was noted that a loss of ABH(O) surface isoantigens was a bad prognostic sign.

ABO Blood-Group System↗
PubMed1992

beta Adrenergic receptor desensitisation may serve a cardioprotective role.

OBJECTIVE: The aim was to test the hypothesis that beta adrenoceptor desensitisation is a form of cardioprotection whereby the myocardium is protected from the injurious effects of excessive adrenergic stimulation by isoprenaline. METHODS: A new sensitive and specific method of identifying cardiac myocyte necrosis with monoclonal antimyosin was employed. Antibody labelled necrotic cardiomyocytes from male Sprague-Dawley rats (190-300 g) were identified by immunofluorescence. Homologous beta adrenoceptor desensitisation was induced by 9 d pretreatment with isoprenaline infusion (20 mg.kg-1.d-1), and heterologous desensitisation by treatment with 0.15% propylthiouracil in the diet for six weeks. The effects of isoprenaline induced cardiomyocyte injury in these animals were compared with those in control rats. RESULTS: In euthyroid control rats, treatment with the beta adrenergic agonist, isoprenaline, produced prolonged tachycardia and hypotension, and a significant amount of cardiac myocyte necrosis subendocardially. When the same isoprenaline challenge was given to rats pretreated for 9 d with an isoprenaline infusion, the haemodynamic response was markedly attenuated and very little myocyte necrosis was noted. In the model of heterologous desensitisation occurring in hypothyroidism, isoprenaline challenge produced markedly diminished haemodynamic response and little cardiac myocyte necrosis. CONCLUSIONS: In both homologous and heterologous models of beta adrenoceptor desensitisation, the susceptibility of the myocardium to isoprenaline induced cytotoxicity is markedly reduced.

Adrenergic beta-Antagonists↗
PubMed1992

Prevention of structural changes in the heart in hypertension by angiotensin converting enzyme inhibition.

BACKGROUND: The long-term effects of hypertension on the heart culminate in congestive heart failure. The underlying causes are contractile impairment due to myocyte loss and reduced compliance due to myocardial fibrosis. Newer strategies in antihypertensive therapy must, therefore, focus on prevention of myocardial damage ('cardioprotection') or, if an abnormality has occurred, on reversal towards normal myocardial structure and function ('cardioreparation'). OBJECTIVE: To investigate the question of whether angiotensin converting enzyme (ACE) inhibition can influence myocardial remodelling in hypertension to produce cardioprotective and cardioreparative effects. METHODS AND RESULTS: Infusion of pathophysiological levels of circulating angiotensin II in rats causes cardiac myocyte necrosis, followed by fibroblast proliferation. This necrosis is not secondary to adrenergic activation or raised blood pressure. Similarly, renovascular hypertension results in cardiac myocyte necrosis, which can be prevented by pretreatment with the ACE inhibitor captopril. In established genetic hypertension in rats, sustained treatment with high-dose lisinopril normalizes the blood pressure, reverses left ventricular hypertrophy, reverses excessive interstitial and perivascular fibrosis (and consequently the impaired compliance), and reverses excessive coronary artery medial thickening (thereby normalizing coronary vascular reserve). With a low dose of lisinopril that does not reduce blood pressure significantly, only the excessive fibrosis is reversed. CONCLUSION: ACE inhibition has demonstrated promising myocardial remodelling effects in experimental models of hypertensive heart disease.

Angiotensin II↗