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Biomedical subjects

C Y Lo

Publications and source records attributed to C Y Lo.

At least 109 records · Page 6Linked to original sources
PubMed1993

Isoniazid induced encephalopathy in dialysis patients.

Three dialysis patients with extrapulmonary tuberculosis developed confusion 4-14 days after commencement of treatment with anti-tuberculosis drugs, despite the use of prophylactic pyridoxine. Full recovery of conscious state resulted within 1 week in all patients after stopping isoniazid. In 2 patients confusion recurred on rechallenge of the drug. The risk factors of isoniazid induced encephalopathy and the dosage of isoniazid in uraemic patients were discussed.

Adult↗
PubMed1992

Choice of palliation for malignant hilar biliary obstruction.

Clinical data from 50 consecutive patients with unresectable hilar tumors situated at or proximal to the common hepatic duct were retrospectively analyzed to aid in the selection of appropriate palliative measures. Thirty-four patients had cholangioenteric bypass (CEB) to either left (28 patients), right (3 patients), or both (3 patients) intrahepatic ductal systems. Sixteen patients had nonoperative drainage (NOD) established either endoscopically (4 patients), percutaneously (9 patients), or using a combined endoscopic-percutaneous approach (3 patients). When compared with patients with CEB, patients with NOD had more frequent medical problems (p less than 0.03) and lower serum albumin levels on admission (p less than 0.03). While comparable postprocedural complications (13 CEB patients versus 4 NOD patients) were observed, patients with NOD had a significantly higher hospital mortality (9 CEB patients versus 9 NOD patients, p less than 0.05). Excluding the 12 patients (6 CEB patients versus 6 NOD patients) who died within 30 days after drainage, the quality of survival of the remaining 38 patients was analyzed with reference to 6 objective parameters. Although patients with NOD had significantly more frequent admissions relating to their catheters (p less than 0.02), there was no qualitative difference in the survival rate between the two groups of patients. For selected high-risk patients with limited life expectancy, NOD should be offered. However, additional prospective studies are required to decide the best choice of palliation for patients who are not at such high risk.

Aged↗
PubMed1992

Surgery for malignant obstructive jaundice: analysis of mortality.

Surgery on patients with malignant obstructive jaundice carries formidable morbidity and mortality rates. Clinical records of 120 consecutive patients who had a serum total bilirubin levels of 100 mumol/L or greater before exploration were analyzed retrospectively to provide guidelines for better management. Although most patients underwent bilienteric bypass to either the extrahepatic (n = 45) or intrahepatic ductal system (n = 28), resection was possible in 32 (26.7%). Complications developed in 42 patients (35%), among whome 12 (10%) required reexploration and 32 (26.7%) died within the same hospitalization. Identification of risk factors associated with hospital deaths after surgery was conducted on 84 of the 120 (group A) patients randomly selected from the entire study period. Based on multivariate analysis, age greater than 65 years, a raised serum aspartate transaminase value greater than 90 IU, and serum urea level greater than 7 mmol/L before surgery were the risk factors selected from 39 different clinical (n = 6), laboratory (n = 26), and operative (n = 7) parameters studied. The predictive value was validated in the remaining 36 patients (group B), and a high-risk patient population had been isolated. Because both serum urea and aspartate transaminase values correlated significantly with the necessity of urgent exploration, aggressive nonoperative treatment should be used to control the emergency. Alternative therapeutic options or perioperative management should be considered for the selected high-risk patients before definitive surgical biliary decompression.

Adult↗
PubMed1990

A new enzyme immunoassay specific for blastomycosis.

A highly specific enzyme immunoassay (EIA) was developed for the serodiagnosis of blastomycosis. Among the earliest sera available from eight active cases of blastomycosis, seven were reactive by EIA, three by immunodiffusion, and three by complement fixation. The one seronegative case was associated with acquired immunodeficiency syndrome (AIDS). No cross-reaction was observed with sera from 12 patients with active histoplasmosis or from five patients with active coccidioidomycosis or from 23 healthy persons. In contrast, all patients' sera cross-reacted in conventional EIAs based on commercial immunodiffusion antigens. The blastomycosis-specific EIA seems to offer sensitivity without compromising specificity. Rheumatoid factors, which could cause false-positive reactions, were controlled for.

Antigens, Fungal↗
PubMed1989

Hyperproliferation of conjunctival fibroblasts from patients with cicatricial pemphigoid.

The characteristic conjunctival scarring in cicatricial pemphigoid is a consequence of subepithelial fibrosis. The fibroblast is the cellular element responsible for fibrosis. To increase the understanding of the pathogenesis of abnormal fibrosis in cicatricial pemphigoid, the growth characteristics of conjunctival fibroblasts, from untreated patients with cicatricial pemphigoid (n = 9) and normal controls (n = 6), were studied in tissue culture. The latent period until fibroblast outgrowth began from the conjunctival explant was determined, as were the plating efficiency and doubling time of cells from first-passage cultures. Outgrowths of fibroblasts from patients with cicatricial pemphigoid appeared significantly sooner than from controls, 8.1 +/- 3.8 vs 19.3 +/- 6.4 (mean +/- SD) days. While there was no significant difference in the plating efficiency between fibroblasts from cicatricial pemphigoid (mean +/- SD, 116.4% +/- 44.6%) and those from controls (71.0% +/- 39.4%), the doubling time was significantly faster for cicatricial pemphigoid than for controls, 26.5 +/- 8.5 vs 50.7 +/- 7.8 hours. Thus, conjunctival fibroblasts from patients with cicatricial pemphigoid are hyperproliferative in tissue culture when compared with normal controls. Therefore, scarring, which characterizes cicatricial pemphigoid, may be due, in part, to excessive fibroblast proliferation.

Aged↗
PubMed1989

Predictive values.

Explore the source record for details and available documents.

Bayes Theorem↗
PubMed1988

An assessment of urease-based enzyme-linked immunosorbent assay.

The use of urease in enzyme-linked immunosorbent assays (ELISAs) offers the advantages of convenience and safety. However, urease-based ELISA, performed in standard microtitre format, could result in false positive reactions upon prolonged incubation. False positive reactions appeared when wells containing substrate solution absorbed ammonia liberated from a reactive well nearby. Thus, the intensity of the false reaction was proportional to that of the urease reaction. The transfer of ammonia was demonstrated by pyrolysis-mass spectrometry. When urease conjugates were compared with peroxidase conjugates in the detection of IgG and IgM, there was no evidence that one enzyme was superior to the other in terms of increasing the sensitivity or the speed of ELISA.

Ammonia↗
PubMed1988

Separation and identification of triglycerides, cholesteryl esters, cholesterol, 7-dehydrocholesterol, dolichol, ubiquinone, alpha-tocopherol, and retinol by high performance liquid chromatography with a diode array detector.

A simple isocratic high performance liquid chromatography (HPLC) system is described that allows separation and identification of cholesteryl esters, triglycerides, ubiquinone, alpha-tocopherol, dolichol, cholesterol, 7-dehydrocholesterol, and retinol. This consisted of a normal phase cyanopropyl column with 0.1% isopropanol in heptane as the solvent. The effluent was monitored with an LKB model 2140 diode array detector which enabled the lipids to be identified by their characteristic absorption spectra. This system was applied to a sample of dog liver in which cholesteryl esters, retinyl esters, triglycerides, ubiquinone, dolichol, cholesterol, and retinol were identified. Retinyl esters and vitamin D esters were identified by their similarity in absorption spectra to retinol and vitamin D. A system to transfer and store the chromatograms on the VAX PDP-11 or an optical disc is also described.

Cholesterol↗
PubMed1988

Brain and optic system pathology in hypocholesterolemic dogs treated with a competitive inhibitor of 3-hydroxy-3-methylglutaryl coenzyme A reductase.

The cholesterol lowering compound lovastatin, a competitive inhibitor of 3-hydroxy-3-methylglutaryl coenzyme A reductase (EC 1.1.1.34 HMG CoA reductase), was given in nine separate experiments to normocholesterolemic dogs at rates up to 180 times the maximum therapeutic dose in man (1 mg/kg/day). Mean serum total cholesterol concentrations were reduced as much as 88% below normal. Clinical evidence of neurotoxicity occurred in up to 37% of animals given 180 mg/kg/day lovastatin for 11 or more days, especially in one laboratory where the dosing regime resulted in higher concentrations of plasma drug levels. Dogs receiving 60 mg/kg/day or less never exhibited neurologic signs. The central nervous system (CNS) of affected dogs exhibited endothelial degeneration and hemorrhagic encephalopathy. Focal extravasation of horseradish peroxidase occurred frequently (6/8) in the retrolaminar optic nerve of asymptomatic or clinically affected dogs given 180 mg/kg/day lovastatin, with endothelial degeneration and discrete optic nerve degenerative lesions interpreted as ischemic. The association between the degree of hypocholesterolemia and occurrence of clinical signs was not exact. Total brain cholesterol was similar in treated and control dogs. Hypocholesterolemic dogs had proportionally lowered serum concentrations of alpha-tocopherol, but oral supplementation of this vitamin did not prevent the neurologic syndrome. Endothelial degeneration in the CNS and optic nerve may have reflected in vitro morphologic effects of HMG CoA reductase inhibitors due to extreme inhibition of nonsterol isoprene synthesis. Retinogeniculate axonal (Wallerian-like) degeneration occurred in greater than or equal to 12% of dogs given 60 mg/kg/day or more lovastatin, with central chromatolysis of occasional retinal ganglion cells. These neuroaxonal changes may have been secondary to vascular effects, but superimposed direct neurotoxic action at the high dosage levels of lovastatin could not be excluded. There was no evidence of drug induced adverse effects in the CNS of dogs given up to 30 mg/kg/day lovastatin for 2 years.

Animals↗
PubMed1987

Inhibition of hydroxymethylglutaryl-coenzyme A synthase by L-659,699.

A beta-lactone isolated from Fusarium sp. has been shown to be a potent specific inhibitor of the enzyme 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) synthase [(S)-3-hydroxy-3-methylglutaryl-CoA acetoacetyl-CoA-lyase (CoA-acetylating), EC, 4.1.3.5] from rat liver. The structure of this beta-lactone, termed L-659,699, is (E,E)-11-[3-(hydroxy-methyl)-4-oxo-2-oxytanyl]-3,5,7-trimethyl-2,4 - undecadienenoic acid. A partially purified preparation of cytoplasmic HMG-CoA synthase from rat liver was inhibited by L-659,699 with an IC50 of 0.12 microM. The enzyme HMG-CoA reductase, beta-ketoacyl-CoA thiolase, acetoacetyl-CoA synthetase, and fatty acid synthase were not inhibited to any extent by this compound. In cultured Hep G2 cells, the compound inhibited the incorporation of [14C]acetate into sterols with an IC50 of 6 microM, while incorporation of [3H]mevalonate into sterols in these cells was not affected. The activity of HMG-CoA reductase in the cultured Hep G2 cells was induced in a dose-dependent manner by incubation with L-659,699. A 37-fold increase in reductase was observed after a 24-hr incubation with 62 microM L-659,699. The effect of a number of analogs of L-659,699 on HMG-CoA synthase is also discussed.

Animals↗
PubMed1982

Complement fixation by antibodies to the alpha toxin of Staphylococcus aureus.

When rabbits were injected with the heat-denatured alpha toxin (toxoid) of Staphylococcus aureus, the immune response was demonstrated by an increase in antitoxin that fixed complement. Such antitoxin was detected in 72% of normal human sera. After fractionation of the antitoxin into two types (the antibinding antibodies and the indirect hemagglutinating antibodies), both types of antibodies were found to fix complement in the standard serological complement fixation test. In addition, the indirect hemagglutinating antibodies were capable of fixing complement when the antigen (alpha toxin or toxoid) was covalently or noncovalently bound to erythrocyte membranes. The fixation of complement by membrane-bound immune complexes did not result in lysis of the carrier erythrocytes. The prevalence of complement-fixing antitoxin in normal humans and animals raised the concern that the outcome of in vivo experiments involving alpha toxin could be influenced by the immune status of the host.

Animals↗
PubMed1979

Immunologic evidence that staphylococcal alpha toxin is oriented on membranes.

Antibodies to staphylococcal alpha toxin were separated into two distinct populations. One population prevented binding of alpha toxin onto erythrocyte membranes. The other population neutralized after the toxin was bound onto erythrocytes and thereby brought about an indirect hemagglutination reaction. The data suggest that alpha toxin has a membrane-binding region.

Animals↗
PubMedDate not supplied

Mediation of beta-endorphin in exercise-induced improvement in insulin resistance in obese Zucker rats.

BACKGROUND: Aerobic exercise including treadmill running has long been used to successfully treat and/or prevent insulin resistance and type-2 diabetes. Increase of plasma beta-endorphin is observed with exercise. The present study was designed to clarify the role of endogenous beta-endorphin in exercise-induced improvement in insulin resistance. METHODS: We used a moderate exercise program consisting of treadmill running at 20 m/min and 0% grade for 1 h/day, 7 days/week, for 8 weeks. Plasma glucose concentration was assessed by the glucose oxidase method. The enzyme-linked immunosorbent assay was performed to quantify the plasma level of beta-endorphin-like immunoreactivity (BER). The glucose disposal rate (GDR) was measured by the hyperinsulinemic euglycemic clamp technique. Changes of the insulin signaling in isolated soleus muscle were then detected by immunoprecipitation and immunoblotting. RESULTS: An increase of plasma BER in parallel with the reduction of plasma glucose was obtained in exercise-trained obese Zucker rats. Different from a marked reduction in sedentary obese rats, the value of insulin-stimulated GDR obtained from the exercised obese rats was reversed to near that of the sedentary lean group, eight weeks after the last period of exercise. This effect of exercise was inhibited by naloxone or naloxonazine at doses sufficient to block opioid micro-receptors. Signaling-related defects in the soleus muscle of sedentary obese Zucker rats, which impaired glucose transporter subtype 4 (GLUT 4), included decreased phosphorylation of insulin receptor substrate (IRS)-1, as well as an attenuated p85 regulatory subunit of phosphatidylinositol 3-kinase (PI3 kinase) and Akt serine phosphorylation. In contrast, exercise training failed to modify the levels of insulin receptor (IR), IRS-1, and IR tyrosine autophosphorylation in obese Zucker rats. CONCLUSION: Enhanced insulin sensitivity via exercise training might be mediated by endogenous beta-endorphin through an increase of postreceptor insulin signaling related to the IRS-1-associated PI3-kinase step that leads to the enhancement of GLUT 4 translocation and improved glucose disposal in obese Zucker rats.

Animals↗
PubMedDate not supplied

Multivariate analysis of risk factors influencing survival in 110 ethnic Chinese with papillary thyroid cancer.

Data from 110 Chinese patients presenting with papillary thyroid cancer to a single institution up to December 1985 have been analyzed to evaluate the possible risk factors affecting survival. There were 83 women and 27 men with an age range of 15 to 78 years (mean 45 years, median 42 years). The longest follow-up period is 39 years and the median 10 years. Cervical lymph node recurrence more than 6 months after surgery developed in 12 patients, of whom 1 died with a concomitant distant metastasis. "Thyroid bed" tumor recurrence, after apparently complete surgery, presented in 10 patients and resulted in 5 deaths. Distant metastases were identified in 17 patients with 7 deaths. Another 4 patients died from advanced local disease incompletely resectable on presentation. The following seven risk factors for survival were selected for multivariate analysis: age, sex, tumor size, histologic evidence of extrathyroidal spread, lymph node recurrence, neck recurrence, and distant metastases. Age, size, neck recurrence, and distant metastases were all significant on univariate analysis. Using Cox proportional hazards regression in the multivariate analysis of these seven factors, only age (p < 0.0001) was shown to be significant. Age over 40 years on first diagnosis was a highly significant indicator of high risk (p = 0.0003, log-rank).

Adolescent↗
PubMedDate not supplied

Adrenal surgery in the elderly: too risky?

Surgical treatment for adrenal disease may be withheld from elderly patients because of concern about prohibitive operative morbidity and mortality. To obtain objective data in our practice, we analyzed the results of adrenalectomy for patients aged 65 years and older. From 1984 to 1993 there were 85 patients (41 men, 44 women) with ages ranging from 65 to 84 years (median 69 years) who underwent adrenalectomy for Cushing syndrome (n = 19), pheochromocytoma (n = 16), adrenocortical carcinoma (n = 7), benign adenoma (n = 26), or primary hyperaldosteronism (n = 17) at our institution. Median follow-up was 26 months (range 1 month to 9.1 years). A retrospective review with respect to preoperative risks and postoperative morbidity and mortality was performed utilizing the American Society of Anesthesiologists (ASA) physical status classification and the modified Goldman multifactorial cardiac risk scheme. Survival was estimated by the Kaplan-Meier methods. Operative mortality was 7% (six patients). No patients with pheochromocytoma or primary hyperaldosteronism died during the postoperative period. Patients undergoing adrenalectomy for adrenocortical carcinoma had a significantly higher operative mortality (43%) (p = 0.006). Postoperative complications developed in 19 patients (22%), and there was a reoperation rate of 6% (5 patients). Nineteen percent of patients required postoperative intensive care admission and had a median stay of 2 days (range, 1-38 days). Median hospital stay was 7 days (range 3-47 days). Seventy-three patients (86%) remained alive at study completion. Two- and five-year survivals were 86% and 84%, respectively. Goldman class II or greater was an excellent predictor of increased morbidity (p = 0.032) and mortality (p = 0.036). With the exception of adrenocortical carcinoma, adrenal surgery for elderly patients can be performed with acceptable morbidity and mortality. The Goldman multifactorial cardiac risk scheme reliably predicts postoperative outcome in this elderly group of patients.

ACTH Syndrome, Ectopic↗