Lipid metabolism disorders, lymphocytes cells death, and renal toxicity induced by very low levels of deoxynivalenol and fumonisin b1 alone or in combination following 7 days oral administration to mice.

SCOPE: In our previous study focused on in vitro interactive effect of Fusarium mycotoxins deoxynivalenol (DON) and fumonisin B1 (FB1), we reported that these toxins tested at low level and in association could lead to additive or synergistic cytotoxic effect. The aim of the present study is to confirm those findings by in vivo study. MATERIALS AND METHODS: Swiss mice were orally administered with low doses of DON (45 µg/kg bw/day), FB1 (110 µg/kg bw/day), and their mixture (DON + FB1) for 7 days. RESULTS: As results, no death or abnormal symptoms were observed in all groups. The significant of loss of weight was observed in females group treated with FB1 and its association with DON. Serum chemistry examinations revealed that disorders in lipid metabolism, renal filtration perturb and a rhabdomyolysis. DON has been found as particular inducer of kidney cell deoxyribonucleic acid (DNA) methylation and blood lymphocytes cell death as measured by lymphocytes DNA fragmentation. Female mice were more sensitive and the mixture of DON and FB1 led to additive or more than additive effect particularly for their target kidney which showed different pattern of toxicity. CONCLUSION: Based on the results of this study, the no-observed-adverse effect level (NOAEL) o both DON and FB1 should be low than 45 µg/kg bw/day and 110 µg/kg bw/day, respectively in mice.

Rapid and simple screening and supplemental testing for HIV-1 and HIV-2 infections in west Africa.

OBJECTIVE: To evaluate a combination of rapid tests as a strategy for screening and supplemental testing of serum for HIV-1 and/or HIV-2 antibodies. DESIGN: Cross-sectional evaluation. SETTING: Projet RETRO-CI, an AIDS research project in Abidjan, Côte d'Ivoire. METHODS: Serum specimens were collected from 1000 consecutive women giving birth in an Abidjan maternal and child health centre and from 185 hospitalized patients. All serum specimens were tested for HIV-1 and HIV-2 antibodies by whole-virus enzyme immunoassay; repeatedly reactive specimens were further tested by virus-specific Western blot and synthetic peptide-based tests. This was the reference strategy against which the algorithm under evaluation was compared. All specimens were subsequently tested by a mixed (HIV-1 and HIV-2) recombinant antigen-based test (Abbott Testpack), followed, if positive, by a rapid synthetic peptide-based test (Genetic Systems Genie) as a supplemental test. RESULTS: According to the reference strategy the prevalence of HIV-1 and/or HIV-2 infection was 13% among the pregnant women and 78% among the hospitalized patients. Compared with the reference strategy, the combination of rapid tests was associated with a sensitivity of 99.6%, a specificity of 99.9%, and positive and negative predictive values of 99.6 and 99.9%, respectively. Four per cent of HIV-2-positive and 1% of HIV-1-positive specimens were considered dually reactive by the rapid test combination. CONCLUSIONS: Synthetic peptide-based tests provide an alternative to Western blots for supplemental testing for HIV-1 and HIV-2. This combination of rapid tests offers performance characteristics comparable to an enzyme immunoassay and Western blot-based strategy, without requiring running water, electricity, or a well-developed laboratory. High-quality serodiagnosis of HIV-1 and HIV-2 infections is possible at the most peripheral levels of the health-care system in developing countries, the limiting factors being the costs of tests and training of staff.

PIP: Researchers from an AIDS research project took blood samples from 1000 consecutive women during childbirth at a maternal and child health center in Abidjan, Cote d'Ivoire, and from 185 hospitalized patients to compare the results of a combination of synthetic peptide-based rapid tests (product names, Testpack and Genie), which check for HIV-1 and HIV-2 antibodies, with those of the Western Blot-based test. They also wanted to see whether the rapid test-based strategy could replace the Western Blot-based test as a supplemental test. The Western Blot indicated the HIV-1 and/or HIV-2 prevalence to be 13% among the new mothers and 78% among the hospitalized patients for an overall prevalence of 23%. 3.3% of all people were positive for both HIV-1 and HIV-2. 17.4% tested positive for just HIV-1. 2.1% were positive for HIV-2. The rapid tests had a sensitivity of 99.6% and a specificity of 99.9%. The positive predictive value was 99.6% and the negative predictive value was 99.9%. The rapid tests identified 4% of the HIV-2 positive samples and 1% of the HIV-1 samples to be dually reactive. These findings demonstrated that rapid synthetic peptide-based assays reliably detect HIV-1 and HIV-2 antibodies and can be supplemental tests. High quality HIV serology can be performed in a setting without running water and electricity which was the case in this study. A further advantage of this strategy is that each test takes only 10 minutes. These tests would have significant effects on HIV testing and counseling, diagnosis, and screening of blood for transfusion in rural areas of developing countries.

Cross-reactivity on western blots in HIV-1 and HIV-2 infections.

To examine cross-reactivity of antibodies to heterologous antigens, on HIV-1 and HIV-2 Western blots, we tested sera from 1362 consecutive tuberculosis (TB) patients and 2127 consecutive blood donors. Specimens positive on enzyme-linked immunosorbent assay (ELISA) for HIV-1 or HIV-2 were further characterized by synthetic peptide-based tests, and tested by HIV-1- and HIV-2-specific Western blots. Dual serologic reactivity on synthetic peptide tests was proportionately more frequent in HIV-positive TB patients than in blood donors, and HIV-2 reactivity less frequent. Positive HIV-1 Western blots were seen in 73-83% of specimens specifically characterized as positive for HIV-2 on synthetic peptide tests. Cross-reactivity to HIV-2 Western blots by HIV-1-positive specimens was significantly more frequent in TB patients (35%) than in asymptomatic donors (9%; P less than 0.001). Using recently recommended criteria for HIV-2 Western blot interpretation (presence of two env bands) reduced the overall proportion of HIV-1-positive specimens having a positive HIV-2 Western blot from 27.5 to 16.4%, with [corrected] minimal effect on sensitivity in the diagnosis of HIV-2 reactivity on specimens positive on synthetic peptide tests.

Rapid and specific diagnosis of HIV-1 and HIV-2 infections: an evaluation of testing strategies.

To identify cost-effective testing strategies for HIV-1 and HIV-2 infections, we evaluated different combinations of tests on serum specimens from 1134 consecutive patients attending tuberculosis treatment centers in Abidjan, Côte d'lvoire. Virus-specific whole-virus enzyme-linked immunosorbent assay (WVE), Western blot (WB) and synthetic peptide enzyme-linked immunosorbent assay (SPE) were used in sequential fashion to determine the true prevalence of infection; 27% were reactive to HIV-1, 5% to HIV-2, and 10% to both viruses. Of 239 specimens positive on WB for both HIV-1 and HIV-2, SPE diagnosed 38% as HIV-1-reactive and 16% as HIV-2-reactive, while 46% remained reactive to both viruses. Using WVE or one of two rapid (5-10 min) mixed (HIV-1 and HIV-2) antigen tests (RMATs) as a screening test, followed by SPE as a supplemental test, gave results with sensitivity of 97.3-99.2%, specificity of 99.5-99.7%, and positive predictive value for diagnosing HIV infection of 99.4-99.6%, with important savings in time and reagent costs. SPE allows more specific distinction between HIV-1 and HIV-2 infections than WB, and could replace it as a supplemental test in many settings. WB may be required for specimens reactive on screening tests but negative on SPE, until sensitivity of the SPE is further evaluated. A mixed antigen screening test followed by SPE seems to be an efficient testing strategy for diagnosing HIV-1 and HIV-2 infections.

Evaluation of HIV serial and parallel serologic testing algorithms in Abidjan, Côte d'Ivoire.

OBJECTIVE: To evaluate HIV serologic testing algorithms based on a combination of three enzyme linked immunosorbent assays (ELISA) for the confirmation of HIV infection in Abidjan, Côte d'Ivoire, where HIV-2 and HIV-1 non-B subtypes are prevalent. METHODS: A total of 1069 human sera with known serologic status, in addition to a seroconversion and low titer antibody panel were initially tested by six ELISA to determine the sensitivity, specificity and delta values of the assays. On the basis of the performance of the assays, three ELISA (Enzygnost, ICE 1.0.2, and Vironostika) were selected for use in a parallel and serial testing algorithm in analyzing 8283 consecutively collected sera. In the parallel testing algorithm, sera concordantly reactive or non-reactive by Enzygnost and ICE 1.0.2 were considered as true positive or true negative, respectively. In the serial algorithm, sera reactive by Enzygnost were retested by ICE 1.0.2. Sera with discordant results were tested by Vironostika, and the results was considered definitive. All reactive sera, plus a random sample of negative sera were tested for confirmation by Peptilav. In addition, a random sample of reactive sera was tested by Western blot. RESULTS: All ELISA had 100% sensitivity; specificities ranged from 96.8 to 100%. Positive and negative delta values of the ELISA were high (range, 6.89 to 46.07 and -2.05 to -5.75, respectively). Of the 8283 sera, 2054 were considered true positives and were correctly classified by the parallel testing algorithm (sensitivity, 100%). Of the 6229 true negative sera, 6226 were negative by the parallel testing algorithm (specificity, 99.95%). The sensitivity of the serial algorithm was 99.96%, and specificity was 99.95%. None of the 250 concordant ELISA-negative sera in the algorithm that were randomly tested in Peptilav was positive; similarly, all of the 103 concordant ELISA-positive sera were confirmed by Western blot. The three-ELISA algorithm resulted in reagent cost-savings of at least 50% compared with the Peptilav-based algorithm. CONCLUSION: These results suggest that a combination of ELISA using different principles or antigens in a serial or parallel algorithm is an efficient and cost-effective alternative to the standard algorithm in areas where HIV-1 and HIV-2 are prevalent.

Sexually transmitted diseases and human immunodeficiency virus infections in women attending an antenatal clinic in Abidjan, Côte d'Ivoire.

A cross-sectional survey was conducted among women attending an antenatal clinic in Abidjan to determine the prevalence of sexually transmitted diseases (STDs) and HIV infection, and to identify factors associated with the presence of gonococcal and/or chlamydial cervical infection. Among 546 women, 3.7% had a gonococcal infection and 5.5% had a chlamydial infection. The seroprevalence of syphilis and HIV was 1.1% and 16.2% respectively. Gonococcal and/or chlamydial cervical infection was associated with young age, the presence of endocervical mucopus and with more than 10 polymorphonuclear leucocytes per high power field in a vaginal smear. None of these associated factors had a large enough predictive value to allow its use as a diagnostic criterion. Sexually transmitted diseases are common in pregnant women in Abidjan. The development of rapid, inexpensive diagnostic tests for STD is a priority to improve the care of women attending antenatal clinics in the developing world.

Regulated expression of a highly conserved regulatory gene cluster is necessary for controlling photosynthesis gene expression in response to anaerobiosis in Rhodobacter capsulatus.

We utilized primer extension analysis to demonstrate that the divergently transcribed regB and senC-regA-hvrA transcripts contain stable 5' ends 43 nucleotides apart within the regB-senC intergenic region. DNA sequence analysis indicates that this region contains two divergent promoters with overlapping sigma70 type -35 and -10 promoter recognition sequences. In vivo analysis of expression patterns of regB::lacZ and senC-regA-hvrA::lacZ reporter gene fusions demonstrates that the regB and senC-regA-hvrA transcripts are both negatively regulated by the phosphorylated form of the global response regulator RegA. DNase I protection assays with a constitutively active variant of RegA indicate that RegA binds between regB and senC overlapping -10 and -35 promoter recognition sequences. Two mutations were also isolated in a regB-deficient background that increased expression of the senC-regA-hvrA operon 10- and 5-fold, respectively. As a consequence of increased RegA expression, these mutants exhibited elevated aerobic and anaerobic photosynthesis (puf) gene expression, even in the absence of the sensor kinase RegB. These results indicate that autoregulation by RegA is a factor contributing to the maintenance of an optimal low level of RegA expression that allows responsiveness to activation by phosphorylation.

Isolation and in vitro phosphorylation of sensory transduction components controlling anaerobic induction of light harvesting and reaction center gene expression in Rhodobacter capsulatus.

Anaerobic induction of light harvesting and reaction center gene expression involves two transacting factors termed RegA and RegB. Sequence and mutational analysis has indicated that RegA and RegB constitute cognate components of a prokaryotic sensory transduction cascade with RegB comprising a membrane-spanning sensor kinase and RegA a cytosolic response regulator. In this study we have purified RegA, as well as a truncated portion of RegB (RegB') and undertaken an in vitro analysis of autophosphorylation and phosphotransfer activities. Incubation of RegB' with [gamma-32P]ATP and MgCl2 resulted in phosphorylation of RegB' (RegB' approximately P) over a 20-min incubation period. Incubation of RegB' approximately P with RegA resulted in rapid transfer of the phosphate from RegB' to RegA. In analogy to other characterized prokaryotic sensory transduction components, mutational and chemical stability studies also indicate that RegB' is autophosphorylated at a conserved histidine and that RegA accepts the phosphate from RegB at a conserved aspartate.

Rapid emergence of AIDS in Abidjan, Ivory Coast.

Between July and November, 1988, 1501 consecutive adult medical admissions to the two largest hospitals in Abidjan, Ivory Coast, were studied. The overall prevalence of infection with human immunodeficiency virus (HIV) types 1 and 2 was 43% in hospital A and 28% in hospital B. AIDS accounted for 19% and 9%, respectively, of medical admissions to the two hospitals, and for 33% of medical deaths in hospital A. The risk of death was significantly higher in HIV-seropositive patients with acquired immunodeficiency syndrome (AIDS) (risk ratio 2.5, 95% confidence interval [CI] 2.0-3.2) and in HIV-positive patients who did not meet the AIDS case-definition (risk ratio 1.7, 95% CI 1.3-2.3) than HIV-negative patients. The male/female ratio of the 265 cases of AIDS identified was 4.8. 50% of patients with AIDS were seropositive for HIV-1 only, 4% for HIV-2 only, and 46% reacted serologically to both viruses. The minimum incidence of AIDS in adult male and female residents of Abidjan (per million per year) is estimated at 1447 and 340 cases, respectively. AIDS in this West African city has emerged as a major public health problem.

PIP: Between July and November 1988, 1501 consecutive adult medical admissions to the 2 largest hospitals in Abidjan, Ivory Coast, were studied. The overall prevalence of infection with human immunodeficiency virus (HIV) types 1 and 2 was 43% in hospital A and 28% in hospital B. AIDS accounted for 19% and 9%, respectively, of medical admissions to the 2 hospitals, and for 33% of medical deaths in hospital A. The risk of death was significantly higher in HIV-seropositive patients with acquired immunodeficiency syndrome (risk ratio 2.5, 95% confidence interval (CI) 2.0-3.2) and in HIV-positive patients who did not meet the AIDS case-definition (risk ratio 1.7, 95% CI 1.3-2.3) than HIV-negative patients. The male/female ratio of the 265 cases of AIDS identified was 4.8. 50% of patients with AIDS were seropositive for HIV-1 only, 4% for HIV-2 only, and 46% reacted serologically to both viruses. The minimum incidence of AIDS in adult male and female residents of Abidjan (per million per year) is estimated at 1447 and 340 cases, respectively. AIDS in this West African city has emerged as a major public health problem. (Author's).

Epidemiology and transmission of HIV-2. Why there is no HIV-2 pandemic.

Although human immunodeficiency virus type 1 (HIV-1) and HIV-2 share modes of transmission, their epidemiologic characteristics differ and international spread of HIV-2 has been very limited. Recently, the prevalence of infection with HIV-1 but not HIV-2 has increased rapidly in different West African countries, where HIV-2 was probably present earlier. Among 19,701 women of reproductive age tested in Abidjan, Ivory Coast, between 1988 and 1992, the prevalence of HIV-1 infection increased from 5.0% to 9.2%, while that of HIV-2 declined from 2.6% to 1.5%. Differences in viral load may be responsible: reported results of virus culture and polymerase chain reaction assays suggest that at high CD4+ T-lymphocyte counts viral load is lower in HIV-2-infected than in HIV-1-infected persons; the efficacy of heterosexual and perinatal transmission of HIV-2 is less efficient than that of HIV-1 at this stage. At low (< 0.20 x 10(9)/L [< 200/microL]) CD4+ T-lymphocyte counts, virus isolation is equally successful for both viruses, and the efficacy of heterosexual transmission is similar. Differences in HIV-1 and HIV-2 natural history are reflected in differences in viral load, that for HIV-2 being lower until immunodeficiency is severe. Differences in viral load throughout most of the natural history of infection appear to correlate with lower transmissibility of HIV-2 than HIV-1, and are the likeliest explanation for their markedly different global epidemiology.