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Biomedical subjects

C Venter

Publications and source records attributed to C Venter.

5 recordsLinked to original sources
PubMed1998

Correlation among total lymphocyte count, absolute CD4+ count, and CD4+ percentage in a group of HIV-1-infected South African patients.

Depletion of CD4+ T cells is one of the hallmarks of progression of HIV-1 infection. However, measurement of the CD4+ T-cell count is expensive and often unavailable in less developed areas. Previous studies have suggested that the total lymphocyte count (TLC) can be used to predict a low absolute CD4+ T-cell count. To determine the relationship between TLC and CD4+ T-cell count in HIV-1-infected South African patients, 2777 HIV-1-seropositive patients visiting the Immunology clinic at the Pelonomi Hospital in Bloemfontein, South Africa from April 1991 to April 1997 were included in the study. In total, 3237 observations were used to determine sensitivity, specificity, and likelihood ratios, with 95% confidence intervals, of various cutpoints of the TLC to predict an absolute CD4+ T-cell count of <200 cells/mm3, CD4+ percentage <20%, and CD4+ percentage <15%. Spearman rank correlations were calculated between TLC and CD4+ T cells, CD4+ percentage and CD8+ T cells, as well as between CD4+ and CD8+ T cells. Results demonstrated that a TLC of 2 x 10(9)/L or less had a sensitivity of 90.3% to detect patients with a CD4+ T-cell count of <200 cells/mm3, but a specificity of only 53.7%. When the TLC cutoff value was lowered, specificity increased but sensitivity decreased. For the observations as a group, a correlation (r = 0.704) between CD4+ T-cell count and TLC was demonstrated, but if the patients were divided into three groups according to their CD4+ T-cell count, this correlation weakened considerably. Therefore, although TLC shows a correlation with CD4+ T-cell count, it is not a good predictor of the CD4+ T-cell count in this population and should preferably not be used in the clinical care of HIV/AIDS patients.

Adolescent↗
PubMed1996

Structure and alternative splicing of the presenilin-2 gene.

Missense mutations in the presenilin-1 (PS-1) and presenilin-2 (PS-2) genes have been shown to be causes of autosomal dominant Alzheimer's disease (the AD3 and AD4 loci, respectively). Alternative splicing has previously been reported in the PS-1 gene. In this study, elucidation of intron/exon boundary sequences revealed that PS-2 is encoded by 10 coding exons. In addition, PS-2 cDNA cloning and RT-PCR using RNA from a variety of normal tissues revealed the presence of alternatively spliced products. These products included species with in frame omissions of exon 8 and simultaneous omissions of exons 3 and 4.

Alternative Splicing↗
PubMed1980

Taste, smell and zinc metabolism in patients with chronic renal failure.

Taste and smell acuity, and zinc concentrations in blood, plasma, red blood cells, and hair were determined in male patients with end stage renal disease (n = 7), male (n = 20) and female (n = 6) patients on maintenance hemodialysis (HD), and male (n = 23) and female (n = 25) control groups. Taste acuity for salt (NaCl), sweet (sucrose), acid (HCl) and bitter (urea) in all 3 patient groups was lower than in the appropriate control group. These differences were significant only for sucrose (male dialysis, p < 0.05), HCl (male uremics not on dialysis, p < 0.01; male dialysis, p < 0.01; and female dialysis, p < 0.05) and urea (male dialysis, p < 0.01). Smell perception was impaired (not significantly) for the male patient groups, but slightly improved (not significantly) for the female patient group. Red blood cell and hair Zn++ concentrations were elevated for the male HD group (p < 0.001). THe plasma zinc concentration was significantly lowered for the male patient groups (p < 0.05). Age showed a negative correlation with pyridine, NaCl, sucrose, and HCl mean detection levels for both male HD patients and control groups. Sensitivity to urea also decreased with age for male HD patient groups, but increased for the male control group. Blood and RBC Zn++ concentrations increased and plasma and hair Zn++ decreased with age for the male HD patients and the male control group. No correlation was observed between Zn++ concentrations and taste and smell mean detection levels.

Adult↗