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Biomedical subjects

V Arendt

Publications and source records attributed to V Arendt.

At least 19 recordsLinked to original sources
PubMed2006

Antiviral efficacy and resistance in patients on antiretroviral therapy in Kigali, Rwanda: the real-life situation in 2002.

Our study aimed to complete the published data on ARV therapy in Africa by describing the baseline situation in Rwanda before the launch of a large ARV programme (ESTHER). Prescription habits, frequency and reasons for treatment interruptions but also antiviral efficay, resistance to ARVs and genotypic variability of the viruses present in Rwanda were analysed. Among the 233 patients included in the study, it appeared that a vast majority (91%) were under triple therapy and that half of them had experienced at least one treatment interruption caused mainly by drug shortage or financial difficulties. Among 60 blood samples analysed, 26 were in virological failure with a viral load above 1000 RNA copies/ml and 11 presented major drug resistance mutations. Finally, virological failure could mainly be explained by the high frequency of treatment interruptions but also by the emergence of drug resistance mutations. Consequently the major objective for the ESTHER programme to improve the situation in Rwanda will be to reduce the drug shortage and facilitate the financial accessibility of the treatments.

Anti-HIV Agents↗
PubMed2004

Simple DNA extraction method for dried blood spots and comparison of two PCR assays for diagnosis of vertical human immunodeficiency virus type 1 transmission in Rwanda.

Dried blood spots (DBS) on filter paper facilitate the collection, transport, and storage of blood samples for laboratory use. A rapid and simple DNA extraction procedure from DBS was developed and evaluated for the diagnosis of human immunodeficiency virus type 1 (HIV-1) infection in children by an in-house nested-PCR assay on three genome regions and by the Amplicor HIV-1 DNA prototype assay version 1.5 (Roche Molecular Systems). A total of 150 samples from children born to HIV-1-infected mothers were collected in Kigali, Rwanda, in parallel as DBS and as peripheral blood mononuclear cell (PBMC) pellets. The results obtained on DBS by the two PCR assays were compared to the results of nested PCR on PBMCs. Of 150 PBMC samples, 10 were positive, 117 were negative, and 23 were indeterminate for HIV-1 infection. In DNA extracted from filter papers and amplified by using the in-house nested PCR, 9 of these 10 positive samples (90%) were found to be positive, and 1 was found to be indeterminate (only the pol region could be amplified). All of the negative samples and all of the 23 indeterminate samples tested negative for HIV-1 infection. When we used the Amplicor DNA test on DBS, all of the 10 PBMC-positive samples were found to be positive and all of the 23 indeterminate samples were found to be negative. Of the PBMC-negative samples, 115 were found to be negative and 2 were found to be indeterminate. We conclude that this simple rapid DNA extraction method on DBS in combination with both detection methods gave a reliable molecular diagnosis of HIV-1 infection in children born to HIV-infected mothers.

Acquired Immunodeficiency Syndrome↗
PubMed2003

Sexually transmitted infections and sexual behaviour among commercial sex workers in a rural district of Malawi.

In Thyolo District, Malawi, a study was conducted among commercial sex workers (CSWs) attending mobile clinics in order to; determine the prevalence and pattern of sexually transmitted infections (STIs), describe sexual behaviour among those who have an STI and identify risk factors associated with 'no condom use'. There were 1817 CSWs, of whom 448 (25%) had an STI. Of these, the commonest infections included 237 (53%) cases of abnormal vaginal discharge, 109 (24%) cases of pelvic inflammatory disease and 95 (21%) cases of genital ulcer disease (GUD). Eighty-seven per cent had sex while symptomatic, 17% without condoms. Having unprotected sex was associated with being married, being involved with commercial sex outside a known rest-house or bar, having a GUD, having fewer than two clients/day, alcohol intake and having had no prior medication for STI. The high levels of STIs, particularly GUDs, and unprotected sex underlines the importance of developing targeted interventions for CSWs and their clients.

Adult↗
PubMed2002

Health seeking and sexual behaviour in patients with sexually transmitted infections: the importance of traditional healers in Thyolo, Malawi.

OBJECTIVES: To describe health seeking and sexual behaviour including condom use among patients presenting with sexually transmitted infections (STIs) and, to identify sociodemographic and behavioural risk factors associated with "no condom use" during the symptomatic period. METHODS: A cross sectional study of consecutive new STI cases presenting at the district STI clinic in Thyolo, Malawi. They were interviewed by STI counsellors after obtaining informed consent. All patients were treated according to national guidelines. RESULTS: Out of 498 new STI clients, 53% had taken some form of medication before coming to the STI clinic, the most frequent alternative source being the traditional healer (37%). 46% of all clients reported sex during the symptomatic period (median 14 days), the majority (74%) not using condoms. 90% of all those who had not used condoms resided in villages and had seen only the traditional healer. Significant risk factors associated with "no condom use" included visiting a traditional healer, being female, having less than 8 years of school education, and being resident in villages. Genital ulcer disease (GUD) was the most common STI in males (49%) while in females this comprised 27% of STIs. CONCLUSIONS: These findings, and especially the extremely high GUD prevalence is of particular concern, considering the high national HIV prevalence in Malawi (9%) and the implications for STI and HIV transmission. There is an urgent need to integrate traditional healers in control activities, encourage their role in promoting safer sexual behaviour, and to reorient or even change existing strategies on condom promotion and STI control.

Adult↗
PubMed2002

HIV prevalence and demographic risk factors in blood donors.

OBJECTIVES: To estimate HIV prevalence in various blood donor populations, to identity sociodemographic risk factors associated with prevalent HIV and to assess the feasibility of offering routine voluntary counselling services to blood donors. DESIGN: Cross-sectional study. SETTING: Thyolo district, Malawi. METHODS: Data analysis involving blood donors who underwent voluntary counselling and HIV testing between January 1998 and July 2000. RESULTS: Crude HIV prevalence was 22%, while the age standardised prevalence (>15 years) was 17%. Prevalence was lowest among rural donors, students and in males of the age group 15-19 years. There was a highly significant positive association of HIV prevalence with increasing urbanisation. Significant risk factors associated with prevalence for both male and female donors included having a business-related occupation, living in a semi-urban or urban area and being in the age group 25-29 years for females and 30-34 years for males. All blood donors were pre-test counselled and 90% were post test counselled in 2000. CONCLUSIONS: HIV prevalence in blood donors was alarmingly high, raising important concerns on the potential dangers of HIV transmission through blood transfusions. Limiting blood transfusions, use of a highly sensitive screening test, and pre-donation selection of donors is important. The experience also shows that it is feasible to offer pre and post test counselling services for blood donors as an entry point for early diagnosis of asymptomatic HIV infection and, broader preventive strategies including the potential of early access to drugs, for the prevention of opportunistic infections.

Adolescent↗
PubMed2001

HIV-associated hematologic disorders are correlated with plasma viral load and improve under highly active antiretroviral therapy.

The relationship between HIV-1 replication and hematologic parameters was examined in two separate studies. The first study was a cross-sectional evaluation of 207 untreated patients. In this study, the proportion of patients with hematologic disorders increased with disease progression. There was a significant inverse correlation between HIV-1 plasma viral load and all hematologic values (r = -0.266 to -0.331). The second study was a longitudinal evaluation of patients on combination antiretroviral therapy (HAART) with hematologic alterations before treatment ( N = 27 with platelets <150,000/microl, 24 with hemoglobin <12 g/dl, 36 with neutrophils <2000/microl and 29 with leukocytes <3000/microl). Samples were analyzed every 3 months for 2 years. At 2 years, >50% of patients experienced a sustained virologic response, with viral loads <500 RNA copies/ml. Hematologic reconstitution occurred progressively for all blood cell lineages and became statistically significant after the sixth month of therapy ( p <.001). Mean values increased from 110 to 180 x 10(3)/microl for platelets, from 10.7 to 12.3 g/dl for hemoglobin (stabilizing finally at 11.4 g/dl), from 1,260 to 2,240/microl for neutrophils, and from 2,260 to 3,600/microl for leukocytes. In conclusion, hematologic disorders are corrected by combination antiretroviral therapy. This suggests a causative role of HIV-1 in hematologic disorders.

Adult↗
PubMed2001

Variant human immunodeficiency virus type 1 proteases and response to combination therapy including a protease inhibitor.

The objective of this observational study was to assess the genetic variability in the human immunodeficiency virus (HIV) protease gene from HIV type 1 (HIV-1)-positive (clade B), protease inhibitor-naïve patients and to evaluate its association with the subsequent effectiveness of a protease inhibitor-containing triple-drug regimen. The protease gene was sequenced from plasma-derived virus from 116 protease inhibitor-naïve patients. The virological response to a triple-drug regimen containing indinavir, ritonavir, or saquinavir was evaluated every 3 months for as long as 2 years (n = 40). A total of 36 different amino acid substitutions compared to the reference sequence (HIV-1 HXB2) were detected. No substitutions at the active site similar to the primary resistance mutations were found. The most frequent substitutions (prevalence, >10%) at baseline were located at codons 15, 13, 12, 62, 36, 64, 41, 35, 3, 93, 77, 63, and 37 (in ascending order of frequency). The mean number of polymorphisms was 4.2. A relatively poorer response to therapy was associated with a high number of baseline polymorphisms and, to a lesser extent, with the presence of I93L at baseline in comparison with the wild-type virus. A71V/T was slightly associated with a poorer response to first-line ritonavir-based therapy. In summary, within clade B viruses, protease gene natural polymorphisms are common. There is evidence suggesting that treatment response is associated with this genetic background, but most of the specific contributors could not be firmly identified. I93L, occurring in about 30% of untreated patients, may play a role, as A71V/T possibly does in ritonavir-treated patients.

Adult↗
PubMed2001

Comparison of DNA sequencing and a line probe assay for detection of human immunodeficiency virus type 1 drug resistance mutations in patients failing highly active antiretroviral therapy.

The resistance of human immunodeficiency virus type 1 (HIV-1) to drugs is a major cause of antiretroviral treatment failure. We have compared direct sequencing to a line probe assay (LiPA) for the detection of drug resistance-related mutations in 197 clinical samples, and we have investigated the sequential appearance of mutations under drug pressure. For 26 patients with virological failure despite the use of two nucleoside analogues and one protease inhibitor (indinavir [n = 6], ritonavir [n = 10], and saquinavir [n = 10]), genotypic resistance assays were carried out retrospectively every 3 months for up to 2 years by using direct sequencing (TruGene; Visible Genetics) and a LiPA for detection of mutations in the reverse transcriptase (INNO-LiPA HIV-1 RT; Innogenetics) and the protease (INNO-LiPA HIV Protease, prototype version; Innogenetics) genes. Comparison of the results from both assays found rare major discrepancies (<1% of codons analyzed). INNO-LiPA detected more wild-type-mutant mixtures than sequencing but suffered from a high rate of codon hybridization failures for the reverse transcriptase. LiPA detected earlier and more frequently than sequencing the transient mixed virus population that contained I84V, which appears before V82A in the protease sequence. Mutations M461, G48V, and L90M were often transient and drug pressure related. In conclusion, direct sequencing and LiPAs give concordant results for most clinical isolates. LiPAs are more sensitive for the detection of mixed virus populations. Mutation I84V appears in minor populations in the early steps of the pathways of resistance to indinavir and ritonavir. The fact that some mutations can be found only transiently and in minor virus populations highlights the importance of a low detection limit for resistance assays.

Acquired Immunodeficiency Syndrome↗
PubMed2001

Compliance with cotrimoxazole prophylaxis for the prevention of opportunistic infections in HIV-positive tuberculosis patients in Thyolo district, Malawi.

OBJECTIVE: To verify compliance with cotrimoxazole prophylaxis in human immunodeficiency virus (HIV) infected tuberculosis (TB) patients during the continuation phase of anti-tuberculosis treatment, and to assess the sensitivity, specificity and positive predictive values of verbal verification and pill counts as methods of checking compliance. DESIGN: Cross-sectional study. METHODS: Cotrimoxazole compliance was assessed in a cohort of TB patients who were attending four TB follow-up centres during the continuation phase of anti-TB treatment between months 4 and 6. Verbal verification of drug intake, physical verification of pill count balance, and urine trimethoprim detection by gas chromatography and mass spectrometry were used for assessing compliance. RESULTS: Using urine trimethoprim detection as the gold standard for compliance, trimethoprim was detected in 82 (94%) of 87 patients in the cohort. Verbal verification of cotrimoxazole intake and objective pill count balances showed high sensitivity and positive predictive values compared with the gold standard of urine trimethoprim detection. CONCLUSIONS: In a rural district in Malawi, compliance with cotrimoxazole as an adjunct to anti-tuberculosis treatment in HIV-infected TB patients was good, and can be assessed simply and practically by verbal verification and pill counts.

AIDS-Related Opportunistic Infections↗
PubMed2001

Genotypic correlates of resistance to HIV-1 protease inhibitors on longitudinal data: the role of secondary mutations.

Direct sequencing of the pol gene was assessed retrospectively with protease inhibitor susceptibility in a longitudinal study. A total of 134 samples from 26 patients were analysed at regular intervals up to 2 years. Patients were included in virological failure despite indinavir, ritonavir or saquinavir based triple-drug therapy. Both the type and number of certain secondary protease mutations modulated the effect of primary mutations on phenotypic resistance. This was notably applicable to L101/V, and to lesser extents to A711V/T. However, combinations of primary mutations, including 154V could predict resistance to the drug used and nelfinavir in more than 80%. In contrast, in vitro cross-resistance to amprenavir was rarely encountered. In addition, there was a relationship between a higher number of key mutations and poorer virological and clinical outcomes, respectively, from 6 and 3 months on. The key mutations were the protease mutations independently conferring phenotypic resistance and/or the reverse transcriptase mutations predicting treatment outcome. This relationship was independent from drug history, viral load and CD4 cell count measurements. In summary, even on a small sample size, sequence-based genotyping seems to be a good prognostic marker when performed longitudinally. In the context of primary resistance mutations, including additional secondary mutations, it may be useful in the prediction of phenotypic and clinical resistance. This should be assessed to optimize treatment monitoring before emergence of broadly cross-resistant virus.

Acquired Immunodeficiency Syndrome↗
PubMed1998

Multiple dideoxynucleoside analogue-resistant (MddNR) HIV-1 strains isolated from patients from different European countries.

OBJECTIVE: To study the prevalence of multiple dideoxynucleoside (ddN)-resistant (MddNR) HIV-1 in European patients under treatment with multiple ddN analogues, and to characterize MddNR strains genotypically and phenotypically. DESIGN AND METHODS: Blood samples from patients after > or = 6 months of treatment with multiple ddN were screened for the MddNR mutation Q151M. After confirmation of MddNR in 15 patients from five European countries, genotypic resistance was evaluated by DNA sequencing of the reverse transcriptase (RT) gene. Phenotypic resistance was measured by the recombinant virus assay. Results were compared with the clinical evolution of the patients. RESULTS: The prevalence of MddNR strains in European patients treated with multiple ddN analogues was 3.5%. Viruses typically contained amino acid substitutions V75F, F77L, F116Y and Q151M in the RT gene. A new mutation, S68G, was frequently associated with MddNR. Phenotypically, viruses displayed high-level resistance to zidovudine (ZDV), didanosine (ddl), zalcitabine (ddC), stavudine (d4T) and partial resistance to lamivudine (3TC) once multiple mutations were present. Under in-vivo treatment pressure, some MddNR strains additionally developed resistance to protease inhibitors or non-nucleoside RT inhibitors (NNRTI). Clinically, most patients had advanced HIV disease with low CD4 cell counts, high viral loads and a rapid progression, but two patients harbouring MddNR virus responded well to dual protease inhibitor associations. CONCLUSIONS: MddNR resistant HIV-1 can be found in European patients. MddNR is characterized by a specific set of drug resistance mutations, cross-resistance to most ddN analogues and a fast clinical progression. MddNR can be associated with protease inhibitor or NNRTI resistance.

Amino Acid Sequence↗
PubMed1998

Haptoglobin polymorphism, iron metabolism and mortality in HIV infection.

BACKGROUND: Three phenotypes of the antioxidant protein haptoglobin are known: Hp 1-1, Hp 2-1 and Hp 2-2. OBJECTIVES: To investigate the outcome of HIV infection according to haptoglobin type. DESIGN AND METHODS: Haptoglobin phenotypes were determined using starch gel electrophoresis in serum obtained from 653 HIV-infected Caucasians in the AIDS reference centers of Gent (n = 184), Antwerp (n = 309), and Luxembourg (n = 160). Survival was compared between haptoglobin types using Kaplan-Meier curves. Plasma HIV-1 RNA was quantified by reverse transcriptase PCR. Serum iron, transferrin saturation, ferritin, and vitamin C were assayed to evaluate iron-driven oxidative stress in 184 HIV-infected patients and 204 controls. RESULTS: The haptoglobin type distribution amongst the patients (17.6% Hp 1-1, 49.9% Hp 2-1, 32.5% Hp 2-2) corresponded to that of the controls. Kaplan-Meier curves showed a higher mortality for the Hp 2-2 group (P = 0.0001; adjusted mortality risk ratio, 1.78; 95% confidence interval, 1.25-2.54). Median survival time was 11.0 years (Hp 1-1 and Hp 2-1) versus 7.33 years (Hp 2-2). Plasma HIV-1 RNA levels prior to antiviral therapy and their increase over 1 year were highest in Hp 2-2 patients (P = 0.03 and 0.003, respectively). The Hp 2-2 type was associated with higher serum iron, transferrin saturation, and ferritin levels and with low vitamin C concentrations. Furthermore, ferritin concentrations were higher in HIV-infected patients than in controls (P < 0.0001). CONCLUSION: HIV-infected patients carrying the Hp 2-2 phenotype show a worse prognosis, which is reflected by a more rapid rate of viral replication (in the absence of antiviral treatment). They also accumulate more iron and oxidize more vitamin C, suggesting that less efficient protection against haemoglobin/iron-driven oxidative stress may be a direct mechanism for stimulating viral replication.

Adult↗
PubMed1996

Computer assisted diagnosis of malformation syndromes: an evaluation of three databases (LDDB, POSSUM, and SYNDROC).

Computer programs which can be used as an aid to diagnose multiple congenital anomaly syndromes have been used for many years, but up to now they have been evaluated very rarely. The diagnostic abilities of three of these systems [LDDB (London Dysmorphology Database), POSSUM (Pictures of Standard Syndromes and Undiagnosed Malformations), and SYNDROC] were analyzed. All three programs are based on an algorithm which defines a diagnosis by a set of phenotypic components all having the same weight (descriptive algorithm). A second algorithm is applied by SYNDROC to rank competing diagnoses in order of probability. This pseudo-Bayesian algorithm provides a coefficient of certitude (CC). For a test the clinical findings of 102 patients who had received a firm diagnosis were used. Two search strategies were tried: "novice's strategy" with all findings taken for a search and "expert's strategy" with a selected set of anomalies. Only those diagnoses that were suggested with the 1st rank, defined as the highest degree of agreement, or the highest CC were studied. The greatest resemblance between suggestions of the databases and the clinical diagnosis was obtained with the expert strategy. The highest number of matches were produced by SYNDROC (80 with expert strategy) and the lowest by POSSUM (54 with novice strategy). The overall agreement between the databases is about 40% for the 1st rank. This number reflects that different authors use different pivotal signs for the description of a syndrome. With the pseudo-Bayesian algorithm 59 cases obtained the highest CC value. Great difficulties exist with the subjective estimates for the calculation of these values; the absolute CC values seem to be meaningless. A small number of unusual cases with special combinations of anomalies provide serious problems for correct diagnosis.

Abnormalities, Multiple↗
PubMed1994

[Short-term ciprofloxacin treatment of bacillary dysentery due to Shigella dysenteriae type 1 in Rwandan refugees].

In 1994, an outbreak of dysentery caused by Shigella dysenteriae type I resistant to all public health antibiotics in vitro occurred among rwandan refugees in Zaïre. The only active antimicrobial agent available was ciprofloxacin. It was administered to hospitalized patients in a conventional 5-day schedule. To ration the supply for the benefit of the greatest number, a randomized blinded study was performed to compare the effectiveness of short-term treatment (1 g of ciprofloxacin in a single daily doses for 2 days) with that of the standard treatment (1 g of ciprofloxacin in two daily doses for 5 days). The study included 57 refugees over the age of 15 years with dysentery. Shigella dysenteriae type I was identified in 26 patients. Except for sex distribution, there was no significant difference in clinical and bacteriologic features of the two populations. Treatment failed in 12 cases, i.e., 7 of 29 patients who received the short-term treatment and 5 of 28 patients who received the standard treatment. Efficacy of ciprofloxacin was not dependent on the mode of treatment, taking into account clinical or bacteriologic criteria. These results indicated that the duration of ciprofloxacin treatment for dysentery caused by Shigella dysenteriae type 1 could be shortened to two days. Short-term treatment has several advantages. One is cost-effectiveness since fluoroquinolones are costly and scarce. Another is to allow treatment of a greater number of patients by improving compliance.

Adult↗