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Biomedical subjects

K M De Cock

Publications and source records attributed to K M De Cock.

At least 127 records · Page 7Linked to original sources
PubMed1991

Oligomeric nature of transmembrane glycoproteins of HIV-2: procedures for their efficient dissociation and preparation of Western blots for diagnosis.

Western blot (WB) analysis of various strains of HIV-2 indicated that transmembrane glycoprotein (TMP) of HIV-2 exists as trimers. These trimers have molecular weights and electrophoretic mobilities in the region of the major external glycoprotein, gp120, resulting in WB misidentification during diagnosis. A simple and rapid procedure was developed using trichloroacetic acid (TCA) to efficiently dissociate oligomeric forms of the TMP to monomers prior to the preparation of WB. This procedure permitted the unambiguous identification of antibodies to gp120 and to the TMP. Use of HIV-2 WB strips without any oligomeric forms of the TMP demonstrated (1) that cross reactivity of HIV-1-positive specimens on HIV-2 WB was mainly directed to Gag and Pol proteins, with some reactivity to gp36/gp41 TMP, but none to gp120; (2) that these strips can substantially reduce the number of specimens falsely identified as dually (HIV-1 and HIV-2) reactive; and (3) that HIV-2-positive specimens reacted to viral gp120 in a strain-specific manner, demonstrating high antigenic variation in this glycoprotein. It is recommended that this general procedure of viral protein dissociation be used for HIV-2 WB preparation.

Blotting, Western↗
PubMed1990

AIDS--the leading cause of adult death in the West African City of Abidjan, Ivory Coast.

In 1988 to 1989, 698 adult cadavers in Abidjan's two largest morgues were studied, representing 38 to 43% of all adult deaths in the city over the study period, and 6 to 7% of annual deaths. Forty-one percent of male and 32% of female cadavers were infected with human immunodeficiency virus (HIV). Fifteen percent of adult male and 13% of adult female annual deaths are due to acquired immunodeficiency syndrome (AIDS). In Abidjan, AIDS is the leading cause of death and years of potential life lost in adult men, followed by unintentional injuries and tuberculosis. In women, AIDS is the second leading cause of death and premature mortality, after deaths related to pregnancy and abortion. AIDS-specific and AIDS-proportional mortality rates may be higher in other African cities where AIDS has been found for a longer time than in Abidjan.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Efficacies of US Food and Drug Administration-licensed HIV-1-screening enzyme immunoassays for detecting antibodies to HIV-2.

To determine the efficacy of enzyme immunoassays (EIAs) for antibodies against HIV-1 in detecting HIV-2-infected blood, we tested 55 HIV-2-positive sera with seven Food and Drug Administration-licensed EIA kits. The percentage detection of HIV-2 sera giving positive reactions with these kits varied between the various manufacturers from 60 to 91%. Observations based on a small number of sera (n = 13), suggest that HIV-2-positive blood collected from apparently healthy people (blood donors, prenatal clinics) are detected with a greater frequency (means = 89%) than blood from AIDS patients or patients (n = 32) hospitalized with other infectious diseases (means = 72%). Based on these results and the low incidence of HIV-2 infection observed in the USA, it was concluded that screening with HIV-2-specific tests would not significantly increase the number of HIV-2-positive people detected by current screening programs. However, due to the poor sensitivity of certain HIV-1 assays for HIV-2 antibodies, HIV-2 sera without cross-reacting antibodies will escape detection. Surveillance for HIV-2 might then be improved by the availability of HIV-1 and HIV-2 combination assays.

Acquired Immunodeficiency Syndrome↗
PubMed1990

A comparison of HIV-1 and HIV-2 infections in hospitalized patients in Abidjan, Côte d'Ivoire.

In late 1988, a cross-sectional study of 1715 adult medical patients hospitalized in Abidjan, Côte d'Ivoire, west Africa, showed an overall prevalence of HIV infection of 46% in men and 28% in women. On the basis of specific testing by whole virus enzyme-linked immunosorbent assay (ELISA), Western blot and synthetic peptide ELISA, HIV-1 infection was found in 25%, HIV-2 infection in 4%, and reactivity to both viruses in 11% of male and female patients combined. People infected with HIV-2, as well as those who were reactive to both HIV-1 and HIV-2, had a frequency of AIDS-associated symptoms and signs similar to that in HIV-1-infected patients, and significantly greater than that in seronegative patients. The significance of dual reactivity, and the natural history and disease spectrum of HIV-2 infection, require further study. Synthetic peptide ELISA is valuable for specific serodiagnosis of HIV-1 and HIV-2 infections. Advanced HIV-2 infection in hospitalized patients in Abidjan is associated with the same symptoms and signs as HIV-1 infection.

Acquired Immunodeficiency Syndrome↗
PubMed1990

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.

Blotting, Western↗
PubMed1989

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.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Study of reactivation of chronic hepatitis delta infection.

Five patients with chronic hepatitis delta virus (HDV) infection suffered spontaneous episodes of liver enzyme elevation on a background of otherwise biochemically stable liver disease. In all five patients these episodes were accompanied by a rise in serum levels of anti-HDV IgM, HDV antigen and HDV RNA. These episodes of increased HDV replication accompanied by biochemical evidence of liver injury are reminiscent of reactivation in chronic hepatitis B. Surges of increased HDV replication may be important in the progression of liver disease in chronic HDV infection.

Adult↗
PubMed1989

HIV-1 and HIV-2 infection associated with AIDS in Abidjan, Côte d'Ivoire.

In September 1987, a seroprevalence study of HIV-1 and HIV-2 infection was conducted among 956 people from different groups in Abidjan, Côte d'Ivoire. Groups examined were hospitalized patients (Internal Medicine and Infectious Disease Departments, Centre Hospitalier Universitaire de Treichville, Abidjan), outpatients at tuberculosis treatment centers, blood donors, women attending an antenatal clinic, and patients attending sexually transmitted disease (STD) clinics. Total HIV infection prevalence ranged from 10% in STD clinic patients and pregnant women to 45% in hospitalized patients on an infectious diseases service. Within groups, HIV-1 infection was 2-6.5 times more prevalent than infection with HIV-2. One-quarter of HIV-seropositive people were serologically reactive to both HIV-1 and HIV-2 on enzyme-linked immunosorbent assay and Western blot. Clinical conditions previously observed in patients with HIV-1 infection were observed in people infected with HIV-2 only, as well as in those with HIV-1 infection and dual serologic reactivity. An isolate of HIV-2 was obtained on culture from a person with wasting disease and chronic fever. The results of this study suggest that infection with HIV-1 and HIV-2 is epidemic in Côte d'Ivoire, and that HIV-2 may be associated with AIDS.

Acquired Immunodeficiency Syndrome↗
PubMed1988

Epidemic yellow fever in eastern Nigeria, 1986.

An epidemic of yellow fever occurred in the eastern part of Nigeria during the second half of 1986. Oju, in Benue State, was the most heavily affected region, but yellow fever also occurred in surrounding areas, particularly Ogoja, in Cross River State. In Oju, the mean attack and mortality rates were 4.9% and 2.8%, respectively. Sex and age specific rates were highest in males and in the 20-29 yr age group. The overall case fatality rate was approximately 50%. Diagnosis was confirmed by IgM capture enzyme-linked immunosorbent assay (ELISA) and complement fixation (CF) tests. Entomological investigations implicated Aedes africanus as the epidemic vector. Oju alone probably had about 9800 cases of yellow fever with jaundice, and some 5600 deaths. Outbreaks of this nature could be prevented by inclusion of yellow fever in the Expanded Programme on Immunisation, in areas subject to recurrent epidemics.

Adolescent↗
PubMed1988

The prevalence of infection with human immunodeficiency virus over a 10-year period in rural Zaire.

In 1985 we tested 659 human serum samples, collected in the remote Equateur province of Zaire in 1976, for antibody to human immunodeficiency virus (HIV). Five (0.8 percent) were positive, and HIV was isolated from one of these. Follow-up investigations in 1985 revealed that three of the five seropositive persons had died of illnesses suggestive of acquired immunodeficiency syndrome (AIDS), and two remained healthy but seropositive. In 1986, a serosurvey we conducted using a cluster-sampling technique in the same region showed a seroprevalence of 0.8 percent in 389 randomly selected residents. The seroprevalence in 283 prostitutes was 11 percent. Patients with AIDS were identified in various hospitals in the province. Risk factors for AIDS included a greater than average number of sexual partners and residence outside the area. We believe that the long-term stability of HIV infection in residents of rural Zaire suggests that social change may have promoted the spread of AIDS in Africa.

Acquired Immunodeficiency Syndrome↗
PubMed1988

Experience with human immunodeficiency virus infection in patients with hepatitis B virus and hepatitis delta virus infections in Los Angeles, 1977-1985.

Stored serum specimens from 723 patients with acute hepatitis B and 228 patients with chronic hepatitis B seen between 1977 and 1985 in the Hepatitis Clinic of the Los Angeles County-University of Southern California Medical Center, Los Angeles, CA, were tested for antibody to human immunodeficiency virus (anti-HIV). Risk factors were ordered hierarchically; cases with multiple risk factors were tabulated only in the risk group listed first on the clinic records. Anti-HIV was first detected in 1979, and by 1983 was found in about half of all homosexual men with chronic hepatitis B. The prevalence was significantly lower in patients with acute hepatitis B than in patients with chronic hepatitis B, and in nonhomosexual subjects compared with homosexual subjects. By 1985, 30 per cent of intravenous drug users with chronic hepatitis B were anti-HIV-positive. The highest annual seroconversion rate for anti-HIV, 21 per cent, was found in homosexual men in 1983. A significant association existed between anti-HIV positivity and hepatitis delta virus infection in homosexual men but not in drug abusers. This study provides data on the natural history of the human immunodeficiency virus epidemic in Los Angeles. Further study on the interaction of these different viruses is warranted.

Acute Disease↗
PubMed1988

Evaluation of the WHO clinical case definition for AIDS in rural Zaire.

The clinical case definition for AIDS proposed by WHO for use in Africa was evaluated against HIV antibody status in 72 patients in rural Zaire. Twenty-one (29%) of the patients were antibody-positive. For diagnosing anti-HIV seropositivity, the case definition had a sensitivity of 52%, a specificity of 78%, a positive predictive value of 50% and a negative predictive value of 80%. Calculation of the positive predictive value at different levels of prevalence of HIV infection suggests that the case definition operates at maximum reliability in selected high-risk groups. Modifications to the case definition should be evaluated to try and improve its sensitivity and positive predictive value.

Acquired Immunodeficiency Syndrome↗
PubMed1987

Chronic splenomegaly in Nairobi, Kenya. I. Epidemiology, malarial antibody and immunoglobulin levels.

Chronic splenomegaly in 131 Kenyan patients was investigated at Kenyatta National Hospital, Nairobi. Patients were allocated to diagnostic groups on the basis of clinical, haematological, parasitological, histological, radiological and endoscopic data. The major diagnostic groups were hyper-reactive malarial splenomegaly, our preferred name for tropical splenomegaly syndrome, (31%), hepatosplenic schistosomiasis (18%), visceral leishmaniasis (5%) and "indeterminate splenomegaly", where no diagnosis could be reached (12%). Another 20% of patients were suffering from various non-schistosomal forms of portal hypertension. A number of specific and rarer causes accounted for the rest of the cases. The tribal and geographical distribution of patients with chronic splenomegaly was compared with the pattern of general medical admissions. Splenomegaly was more frequent than expected in Kamba and Luo patients. Hyper-reactive malarial splenomegaly and hepatosplenic schistosomiasis were common in both groups, whereas visceral leishmaniasis was almost restricted to the Kamba and indeterminate splenomegaly was especially prevalent in the Luo. Malarial antibody and immunoglobulin levels differed significantly between the various diagnostic categories of patients and controls. Malarial serology can be diagnostically useful for chronic splenomegaly, provided results are interpreted in their geographical context.

Antibodies, Protozoan↗