Elevation of viral load by PCR and use of plasma preparation tubes for quantification of human immunodeficiency virus type 1

HIV-1 viral load testing from 51 patients was compared in plasma samples simultaneously processed and stored in primary Vacutainer plasma preparation tubes (PPTs) and PPT sample aliquots transferred in secondary tubes before freezing, using RT-PCR quantification with an ultrasensitive method (the Roche AMPLICOR HIV-1 MONITOR). We concluded that freezing the primary sample in the PPT collection tube can artificially elevate the HIV-1 viral load. We therefore store samples as frozen aliquots in a second tube.

Adsorption of p-nitrophenol on activated carbon fixed-bed

Carbon fixed-beds are usually used to remove organic contaminants. Adsorption in a carbon filter is a dynamic, non-steady process which is not yet completely understood. The objective of this paper is to establish a methodology to simplify the study of this process based on the wave theory, rapid small-scale column test and experimental design/surface response analysis. The constant pattern wave hypothesis was confirmed by the experimental data. The influence of the inlet concentration of p-nitrophenol and the flow rate on dynamic adsorption was studied at 20 degrees C following a central composite design using a second-order model. Both parameters have an important influence on the response variables studied. The methodology used is a useful tool for studying the dynamic process and shows interactions that are difficult to verify by the classical step-by-step method.

Influence of ethanol concentration on the extraction of color and phenolic compounds from the skin and seeds of Tempranillo grapes at different stages of ripening

The aim of this paper is to study how grape ripeness and ethanol concentration affect the extraction of color and phenolic compounds from skins and seeds during the maceration/fermentation process. Simulated maceration assays were carried out with the grapes at three stages of berry development (vitis vinifera cv. Tempranillo) and different percentages of ethanol in the maceration media. Both ripeness and ethanol content have a considerable effect on the extraction of color and phenolic compounds. Of these two factors, ripeness increases the extractability most. The presence of ethanol in the medium facilitates anthocyanin and especially proanthocyanidin extraction, but it also decreases copigmentation phenomena, which can decrease the color intensity. The higher the ethanol concentration is in the maceration media, the higher the astringency of proanthocyanidins.

[Clinical features of cerebral toxoplasmosis in Cuban patients with AIDS]

INTRODUCTION

Neurotoxoplasmosis (NTX) is one of the commonest opportunist infections in patients infected by the human immunodeficiency virus. It presents with a variety of clinical features in the immunocompromised patient.

PATIENTS AND METHODS

We made a horizontal retrospective descriptive study of 88 patients with a diagnosis of NTX treated in the Pedro Kour Institute during a three years period. Our aim was to find which were the most common forms of clinical presentation in our setting and to evaluate the use of paraclinical examinations in reaching the presumptive diagnosis. The patients had clinical examinations, CSF studies, detection of indirect immunofluorescence titres (IFI) for Toxoplasma, imaging studies (CAT) and lymphocyte counts.

RESULTS

The commonest symptoms were: headache in 79%, fever in 55.68%, motor defect in 44.31% and disorders of consciousness in 29.54% of the patients. The IFI titres were negative in 31.54% of the patients, between 1/16 and 1/32 in 38.34% and between 1/64 and 1/1,024 in only 30.07% of cases. The T CD4+ lymphocyte count was less than 200 cells in 66.7% of the patients; 72% of imaging studies showed typical lesions, in association with other disorders in 38% of the cases (lymphomas, cryptococcosis, tuberculous meningoencephalitis and cytomegalovirus encephalitis).

CONCLUSIONS

NTX in a patient with AIDS often presents in our setting with headache and fever, motor deficit and alterations of consciousness. The diagnosis should be confirmed by immunological or imaging studies since in this disease serology and CSF studies are less specific.

Molecular analysis of yeast population dynamics: effect of sulphur dioxide and inoculum on must fermentation

The effects of sulphur dioxide and a commercial starter inoculum on yeast population dynamics have been analysed by a molecular approach. Yeast identification from fermenting Carinyena grape musts was performed by RFLP's of mtDNA and rRNA-coding DNA. As expected, the use of a commercial inoculum speeded up the start of fermentation, while SO2 addition limited the development of non-Saccharomyces species. However, this effect was also observed with yeast inoculation. Further analysis of population dynamics could lead to a recommendation for the reduction of the dosage of SO2 by the addition of appropriate inoculum of yeasts in the must. Furthermore, the timing of inoculum addition could be modified to allow a proper contribution of non-Saccharomyces species. Molecular biology analysis of population dynamics could provide a tool to efficiently reduce the dosage of SO2 and adjust the timing of inoculum addition.