Comparison of six serological assays for human immunodeficiency virus antibody detection in developing countries.

Three commercially available assays for the detection of human immunodeficiency virus (HIV) antibodies-Vironostika enzyme immunoassay (EIA), Wellcozyme competitive EIA, and JLC Allaman indirect immunofluorescence assay--were tested on 300 serum samples from African subjects with and without HIV-related conditions. Two experimental assays both rapid and simple to perform (Biotech dip stick and Cambridge Bioscience latex agglutination) were also evaluated on the same serum samples. The results were compared with those of a commercial Western blot (WB) (immunoblot) assay from Biotech, used as the reference technique. All assays were tested in the laboratory of the AIDS Project in Kigali, Rwanda. Calculated specificity ranged from 90.8% (dip stick) to 98.6% (Vironostika EIA, Wellcozyme competitive EIA, and Cambridge Bioscience latex agglutination). Sensitivity ranged from 95.2% (Cambridge Bioscience latex agglutination) to 98.0% (Vironstika EIA) and JLC indirect immunofluorescence assay). However, the sensitivity of the latex agglutination test improved to 98.6% after the prozone effect was controlled for by serial twofold dilution of latex agglutination-negative, WB-positive samples. In situations with a high prevalence of HIV infection, any one of these tests can be regarded as an alternative to the more expensive, time-consuming, and difficult WB assay.     

Transmural distribution of antioxidant defences and lipid peroxidation in the rabbit left ventricular myocardium

The left ventricular subendocardial and subepicardial layers of six perfused rabbit hearts were tested for enzymatic and non-enzymatic antioxidant defences and for lipid peroxidation. The subendocardium showed significantly lower catalase activity and contents of non-protein thiol compounds and vitamin E associated with a higher degree of lipid peroxidation. The activities of Cu,Zn- and Mn-superoxide dismutases, glutathione reductase, -glutamylcysteine synthetase and -glutamyl transpeptidase showed no significant transmural differences, and Se-independent glutathione peroxidase activity was not detectable in either layer. Comparable results were observed in another group of six unperfused rabbit hearts. In five H₂O₂-perfused rabbit hearts, lipid peroxidation was higher, and myocardial creatine phosphokinase activity lower, in the subendocarium than in the subepicardium. In this group, only the subendocardium had significantly higher lipid peroxidation levels than the control hearts. Thus, a lower antioxidant capacity and a greater oxidative stress are present in the rabbit subendocardium. These findings could provide insight into the problem of subendocardial vulnerability to free radical-mediated processes, such as occurs in ischaemia-reperfusion injury.     

Insulin reduces HBsAg production by PLC/PRF/5 human hepatoma cell line

Summary Although its action at the molecular level is not completely understood, insulin, as well as its antagonist glucagon, certaily plays an important role in the modulation of protein synthesis.In order to observe whether insulin is involved in virus gene expression, we studied its effect on PLC/PRF/5 human hepatoma cell line, which posses HBV DNA sequences integrated at several sites.While human insulin had no effect on cell growth and increased the production of two plasma proteins, a selective inhibitory effect on HBsAg production could be detected.This observation might be useful for further studies both on virus gene expression and insulin action at the molecular level.With 3 Figures     

Effect of chronic elevation of plasma calcium concentration by PTH or vitamin D3 on blood pressure and hypotensive activity of nifedipine in rats

The influence of a chronically elevated total plasma calcium concentration on blood pressure and heart rate was investigated in conscious normotensive rats. The plasma calcium concentration was elevated by continuous subcutaneous infusion with parathormone (PTH) after parathyreoidectomy, and by oral treatment with vitamin D₃. In both groups an elevated blood pressure was observed at the 1st day of treatment only. Blood pressure was returned to pretreatment values from the second day of treatments onaards. No significant changes in heart rate, due to hypercalcaemia, were observed. In hypercalcaemic rats, the calcium entry inhibitor nifedipine proved more potent in reducing blood pressure than in normocalcaemic control animals. Hydralazine was equipotent in reducing blood pressure in both groups. It is suggested, that the vasoconstrictor effects of a chronically elevated total plasma calcium concentration in conscious rats does not obviously result in a chronically elevated blood pressure, but rather in an enhanced sensitivity of the blood pressure towards calcium entry blockade.     

Long-term social isolation in the rat induces opposite changes in binding to alpha 1- and alpha 2-adrenoceptors in the brain and vas deferens

Rats isolated at the time of calcification of the incisors show, after 14-18 months of social deprivation, an increased number of alpha 1-adrenoceptors labeled with [3H]WB 4101, both in the striatum and in the vas deferens, as well as a decreased number of alpha 2-adrenoceptors labeled with [3H]-clonidine in the vas deferens. Social isolation does not, however, modify the density of [3H]clonidine binding sites in the cerebral cortex. The functional state of alpha-adrenoreceptors in the vas deferens from isolated rats appears to correlate with the binding studies since the isolated tissue is hypersensitive to the contractile effect of exogenous noradrenaline and subsensitive to the inhibitory effect of clonidine on the electrically stimulated preparation.     

Do food antigens play a role in the pathogenesis of some cases of human glomerulonephritis?

Circulating immune complexes after a test meal were measured with three methods (PEG precipitation, Clq-ELISA and the indirect granulocyte phagocytosis test) in 10 controls, two symptomless persons with selective IgA deficiency and 14 patients with various types of glomerulonephritis, of which two patients (with idiopathic membranous glomerulopathy and local focal glomerulonephritis) also had selective IgA deficiency. The PEG and Clq-ELISA test did not show significant differences between the groups. In the two symptomless persons with selective IgA deficiency and in the patient with local focal glomerulonephritis and selective IgA deficiency the indirect granulocyte phagocytosis test (IGFT) showed a reproducible increase in IgG, IgM and complement containing immune complexes. In the last patient multiple food antigens were probably responsible for this phenomenon, a rapid amelioration of kidney function could be induced three times by giving an antigen free diet.     

Demonstration of skin-derived antileukoproteinase (skalp) and its target enzyme human leukocyte elastase in squamous cell carcinoma

Skin-derived antileukoproteinase (SKALP), also known as elafin, is a strong and specific inhibitor of elastase and proteinase 3. SKALP is not present in normal epidermis, but is expressed by epidermal keratinocytes under hyperproliferative conditions such as psoriasis, wound healing, and in cell culture. In human epidermal tumours, SKALP is differentially expressed and restricted to tumours with distinct squamous differentiation. We have studied the presence of both SKALP and one of its known target enzymes, leukocyte elastase, in 41 squamous cell carcinomas of the skin. SKALP expression correlated with the degree of differentiation: strong expression was seen in well-differentiated cells and expression was absent in poorly differentiated tumour cells. Most of the squamous cell carcinomas showed elastase-positive cells in the tumour stroma and also within the tumour cell nests. SKALP may interfere with the proteoloytic activity of infiltrating inflammatory cells or with hitherto unknown proteinases from the tumour cells. We hypothesize that in squamous cell carcinoma progressive loss of SKALP expression could facilitate tumour spread.     

Human herpesvirus type 6 reactivation after haematopoietic stem cell transplantation

Human herpesvirus type 6 (HHV6) is known to reactivate after hematopoetic stem cell transplantation (HSCT) and has been suggested to be associated with increased mortality and severe clinical manifestations, including graft versus host disease (GvHD). The exact etiological role of HHV6 reactivation in increased morbidity and mortality after HSCT remains unclear. This review will focus on the current available evidence of HHV6 reactivation after HSCT and its immuno-modulatory capacities, with particular emphasis on the severe complication GvHD. At present, no effective specific antiviral treatment for HHV6 reactivation has been identified. The currently available antiviral agents are outlined, as well as possible future strategies for the treatment of HHV6 reactivation. Non-toxic, specific treatment or prevention of HHV6 reactivation might improve the safety and efficacy of the HSCT procedure.     

Multi-residue analysis of anabolics in calf urine using high-performance liquid chromatography with diode-array detection

We describe the development of an HPLC method with diode-array detection (DAD) for the analysis and identification of 20 substances with anabolic properties, that are considered as potential growth promoters, to be used for the analysis of extracts of calf urine samples. The substances are separated on an RP-Select B column using a mobile phase consisting of a mixture of acetonitrile and water. Gradient elution from 43-76% acetonitrile in water with a concave curve was used to achieve a good separation of the compounds with an acceptable analysis time. For the identification, a retention parameter and the UV spectrum were used. The retention parameter was the retention time corrected with a reference mixture. The latter reduced the standard deviations to about 25% of their original values. The limits of detection of the HPLC system ranged from 0.5-5 ng injected amount for the androgens, progestagens, stilbenes and resorcylic acid lactones and to 5-10 ng injected amount for the oestrogens. After extraction from urine the limits of detection were increased by the presence of matrix components, but they were between 5 and 10 ng injected amount for most of the substances.     

Effect of the Addition of Vancomycin on the Performance of an Automated Nonradioactive System for Detection of Mycobacteria

 A recently developed automated, nonradioactive system for the detection of mycobacteria (MB/BacT; Organon Teknika, Belgium) has provided good results, but the contamination rate was found to be higher than that obtained with the radiometric Bactec 460 system (Becton Dickinson, USA). In the present study, the effects of adding vancomycin (1 μg/ml) to the antibiotic mixture of the nonradioactive system were evaluated, and the performance of the system with versus without vancomycin was compared. Three hundred sputum samples were tested, using the radiometric system as the reference method. Mycobacteria were isolated from 47 (15.7%) samples. The nonradioactive system with and without vancomycin detected 42 and 43 strains, respectively; the time to detection was 1 day shorter with the medium without vancomycin (15.7 days vs. 14.3 days). The radiometric system detected 42 strains of mycobacteria in a mean detection time of 13.6 days. Contamination rates with the nonradioactive system were 6.7% in the medium without vancomycin and 2.7% in the medium with vancomycin. The latter figure was approximately the same as the contamination rate found with the radiometric system (2.3%). Our data suggest that the addition of vancomycin considerably reduces the number of contaminants in the MB/BacT medium without affecting the performance of the system.