Antigenic variation of the dominant gp41 epitope in Africa.

OBJECTIVE: To determine the value of (combinations of) synthetic peptides representing immunodominant sites on HIV-1/HIV-2 transmembrane proteins for the detection and discrimination between HIV-1 and HIV-2 infection in various populations. DESIGN AND METHODS: Two 24-mer synthetic peptides derived from immunodominant sites on the HIV-1 and HIV-2 transmembrane proteins were used separately, in combination (env 1/2), and in combination with recombinant p24 (p24/env) in enzyme-linked immunosorbent assays. RESULTS: Positive reactions with env-1 were found in 150 out of 150 (100%) samples from Dutch AIDS patients, 60 out of 60 (100%) samples from Dutch homosexual men obtained 1 year after HIV-1-antibody seroconversion, 29 out of 30 (96.7%) samples from these men obtained at the time of HIV-1-antibody seroconversion, 40 out of 41 (97.6%) samples from East Africans with AIDS-related symptoms, and three out of 29 (10.3%) samples from West Africans with HIV-2 infection (including a sample from an individual infected with both HIV-1 and HIV-2). Positive reactions with env-2 in these study populations were 11 out of 150 (7.3%), nine out of 60 (15%), none out of 30 (0%), 25 out of 41 (60.9%) and 29 out of 29 (100%), respectively. In the samples with dual reactivity, true versus cross-reactivity could generally be differentiated on the basis of large differences in optical density values in the respective assays. All samples reacted positively with p24/env; 308 out of 310 (99.3%) were positive in the env 1/2 assay. Four East African samples that had negative or only weakly positive reactions with env-1 showed a noticeably stronger reaction with variant peptides derived from Central African isolate sequences. In all samples from HIV-1-infected Dutch homosexual men, the strongest signal was detected using the env-1 peptide sequence, which is derived from European and American isolates. CONCLUSIONS: Small peptide antigens may permit the detection of strain-specific antibodies, allowing serological characterization of HIV isolates.

Comparison of Pharmacia Chlamydia EIA, IDEIA and cell culture in the detection of urogenital chlamydial infection.

Two commercial test kits, Pharmacia Chlamydia EIA (PhEIA) and IDEIA Chlamydia Test, for the identification of Chlamydia trachomasis and McCoy cell culture were compared in urogenital specimens. The sediments of the transportation buffers of specimens with discordant results were investigated for elementary bodies (EB) with fluorescein-labelled antichlamydial antibodies. The prevalence of chlamydial infection among the men was 16% (48 of 293), 47 culture positive and one EB positive, and among the women 10% (10 of 97), 10 culture positive. In men, the sensitivity of PhEIA, IDEIA and culture was 71%, 40% and 98%, respectively. In women, irrespective of site, corresponding figures were 100%, 80% and 100%. The specificity and positive predictive values were 100% for both enzyme immunoassays in men and women. The low sensitivity of IDEIA could not be explained by the degree of infection as measured by the number of inclusion bodies in cell culture, the presence of antigen as measured by the number of EBs or the sampling order.

The spontaneous variation of catheter life in long-stay geriatric inpatients with indwelling catheters.

The spontaneous variation of catheter life, i.e. the time in days between catheter changes, was observed in 20 long-stay geriatric inpatients with initially short catheter lives. The study ran for 6 months. The catheter regimen was standardized throughout the study. The intra-individual and inter-individual catheter lives showed considerable variation. Each patient retained his individual pattern of catheter life. It is concluded that, despite the variation of isolated catheter lives, the median value of repeated observations of catheter life provides a reliable parameter of catheter function.

The bacteriuria in long-stay geriatric inpatients with an indwelling catheter.

Long-stay geriatric inpatients with an indwelling urinary catheter are harassed by foul-smelling urine, urine leakage, and frequent catheter blockages. It is reasonable to assume that catheter-induced bacteriuria plays an essential role in the catheter problems of these patients. An attempt to reduce the catheter-induced bacteriuria was made by the introduction of a latex catheter coated with a layer of copper metal. The antibacterial properties of the copper-coated catheters studied were, however, insufficient, probably due to too small amount of copper on the catheter. The copper layer was dissolved from the catheter in a few days. The effective time of copper treatment thus became too short.

Randomized double-blind study of prophylactic methenamine hippurate treatment of patients with indwelling catheters.

Catheterized patients with heavy bacteriuria and short catheter life received a short-course of antimicrobial therapy and then were allocated at random to double-blind treatment for 5 months with methenamine hippurate (MH), 1 g three times daily, or placebo 1 g 3 times daily. MH treatment reduced the number of catheter blockages and instances of spontaneous removal of the catheter, and doubled catheter life (p less than 0.001). It is suggested that the doubled catheter life was due to the reduced bacteriuria and lowering of urinary pH.

Urinary pH and the indwelling catheter.

The pH of the urine within a blocked indwelling catheter was significantly higher than the pH of the first urine portion from the new catheter. This observation suggests that the urinary pH was changed in an alkaline direction within the indwelling catheter, probably due to the production of ammonia induced by urease from Proteus strains. This pH gradient could only be demonstrated under conditions where the circadian pH variations of the urine within the individual could be neglected.

Effect of short-term high-dose treatment with methenamine hippurate on urinary infection in geriatric patients with an indwelling catheter. IV. Clinical evaluation.

An evaluation has been made of the clinical and laboratory effects of short-term (34 days), high-dose (2g x 3 daily) treatment with methenamine hippurate (MH) of 14 geriatric patients with an indwelling catheter and clinical features of urinary tract infection. During MH treatment the number of catheter changes was halved, each catheter remaining in situ for an average of 12.0 days as compared to 6.2 days in the pre-treatment control period and 5.2 days in the post-treatment control period; the difference is significant (p = 0.008; Friedman two-way analysis of variance). Urine pH was reduced (pH 7.0--6.5--7.0; p = 0.01) and the standard bicarbonate in blood was slightly elevated (24.1--25.7--25.0 mmol/l; p= 0.008) during the MH treatment period, when compared to pre- and post-treatment control periods. It is suggested that MH treatment reduced the complications associated with indwelling catheters due to reduction in urine pH, bacteriuria, and pyuria. Blockage of catheters is thought to be due to intraluminal salt precipitations with trapping of clumps, and is primarily not correlated with urine viscosity.

The effect of short-term high-dose treatment with methenamine hippurate of urinary infection in geriatric patients with indwelling catheters. I. The preparation and morphology of a quantified urine sediment.

A quantified sediment of the urine from patients with indwelling catheters was prepared by fixation of 0.1 ml urine in 0.9 ml 2% glutaraldehyde immediately after sampling. Slide preparations were then made from 0.2 ml of the glutaraldehyde suspensions by means of a cytocentrifuge. Bacteria and epithelial cells were properly contrasted by the May-Grünwald-Giemsa stain but haematoxylin-eosin and the Papanicolaou stain were superior as regards leukocyte morphology. It is suggested that glutaraldehyde-cytocentrifuge preparations of the urine cytology may be useful in the evaluation of urinary infection and in the evaluation of the therapy of urinary infection.

The effect of short-term high-dose treatment with methenamine hippurate of urinary infection in geriatric patients with indwelling catheters. II. Evaluation by means of a quantified urine sediment.

The urine sediment of 12 geriatric patients with indwelling catheters was quantified by the glutaraldehyde-cytocentrifuge method prior to, during and after a clinical trial of methenamine hippurate (MH), 2 g x 3 daily given for 34 days as the sole therapeutic agent for the urinary tract infection. The median leukocyte concentration in the urine of these patients was 100 cells/microliter (Q1 - Q3 50-350), i.e. tenfold higher than the upper normal limits reported in healthy probands. The median bacteriuria in the control period was 12 x 10(5) bacteria/ml urine, interquartile range 10-60 x 10(5) bacteria/ml and extreme individual values 300-500 x 10(5) bacteria/ml. Hematuria, defined as greater than or equal to 24 erythrocytes/microliter urine, was not prominent and could not be correlated with MH treatment, nor with catheter changes. The reported observations suggest that short-term high-dose treatment with MH as sole therapeutic agent reduced pyruria and bacteriuria in the group of patients studied.

Locomotion and phagocytosis of polymorphonuclear leukocytes (PMNs) in infected urine. Reversal of PMN polarity.

The appearance of polymorphonuclear leukocytes (PMNs), fixed during locomotion and phagocytosis in deposits of infected urine, is described. By comparison with previous observations on vital PMNs, it is inferred that the anterior lamellipodium is the direction-choosing and prey-catching cell organelle. During phagocytosis the lamellipodium may assume such proportions that a reversal of cell polarity is produced, i.e., the lamellipodium forms the handle of a hand-mirror cell.