Absence of hybridization with the wild-type and mutant rpoB probes in the Genotype MTBDRplus assay detects 'disputed' rifampicin mutations.

OBJECTIVE: Mycobacterium tuberculosis isolates that fail to hybridize to at least one rpoB wild-type or any mutation probe on the Genotype MTBDRplus strip are assumed to be rifampicin-resistant. However, the precise mutation(s) are unknown. We sought to identify the mutations in isolates with such hybridization patterns and determine if the mutations are associated with resistance to rifampicin. METHODS: In this study, 275 M. tuberculosis isolates were screened with the Genotype MTBDRplus assay to identify isolates with the hybridization pattern. These isolates were sequenced and their minimum inhibitory concentrations (MIC) determined using the Bactec MGIT 960 system. RESULTS: Among the 275 isolates tested, 15 (6%) isolates with the hybridization pattern were identified. Sequencing showed that failure to hybridize to rpoB wild-type probes resulted from the presence of 'disputed' rifampicin mutations, which are mutations not always associated with a rifampicin-resistant phenotype. All, except 3/15, isolates had a rifampicin-resistant phenotype (MIC > 1 µg/mL). One of the three isolates with a rifampicin-susceptible phenotype had the same mutation at position 526 (His526Leu) as another isolate that had a rifampicin-resistant phenotype. CONCLUSION: The recommendation of the Genotype MTBDRplus assay to assume rifampicin resistance based solely on failure to hybridize to rpoB wild-type probe allows the identification of important RIF-resistant isolates. About 20% (3/15) of such isolates could be missed by relying only on the standard MGIT 960 DST assay for drug susceptibility testing.

Mentoring for early-career women in health research: the HIGHER Women Consortium approach.

Attracting and retaining women in health research is crucial as it will maximize creativity and innovation as well as increase gender competency and expertise in the field. To help address the gender gap in the research for health field in Cameroon, some women research scientists formed the Higher Institute for Growth in HEalth Research for Women (HIGHER Women) consortium to support and encourage the growth of women research scientists through a training institute with a Mentor-Protégé Program (MPP). The consortium set up a MPP aiming at providing professional guidance to facilitate protégés' growth and emergence in health research. The consortium has conducted two workshops aiming at increasing the early-career women's skills needed to launch their career and focusing on proposal writing with the aim of producing a fundable project. Since 2015, the consortium has brought together approximately 100 women comprising of 80 protégés. The most significant outcome is in the protégés' feedback from their annual evaluations. The protégés are now more likely to submit abstracts and attend international conferences. Some grants have been obtained as a result of the working relationship with mentors. The HIGHER women consortium works to develop a pipeline of women leaders in health research by fostering growth and leadership culture through their MPP.

[Pregnancy outcome in a group of Cameroonian women with uterine fibroids]. / Evolution de la grossesse sur un utérus fibromyomateux chez un groupe de femmes camerounaises.

INTRODUCTION: Uterine fibroids are the most common benign tumor seen in women at reproductive age. The association of pregnancy and uterine fibroids is about 0.5 to 4%. METHODOLOGY: In order to evaluate the complications of this association in our milieu, we carried out this prospective study. The main objective was to compare the incidence of complications of pregnancy and delivery in two groups of women: group 1 (women with uterine fibroids) and group 2 (women without fibroids). They were matched (ratio 1/1) on women age (plus or minus one), gestational age, gravidity (plus or minus one) and parity. RESULTS: Eighty patients in each group 1 were recruited. The mean age was 31.2 years in group 1 and 30.8 years in group 2. Degeneration of fibroids occurred in 15% of cases. The incidence of threatened abortion (51.3% versus 18.8%; RR: 2.7 [1.7-4.5]; p=0.00002), threaten premature delivery (26.3% versus 10%; RR: 2.6 [1.2-5.6]; p=0.008), premature delivery (22.5% versus 7.9%; RR: 2.9 [1.2-6.9]), tocolytic treatment (48.8% versus 20.0%; RR: 2.4 [1.5-4.0]; p=0.0001) and Caesarean section (40% versus 13.8%; RR: 3.1 [1.6-5.9]; p=0.0001) were significantly increased in group 1 than in group 2. We also noticed a moderate increased of the incidence of abortions (11.3% versus 5%; RR: 2.3 [0.7-7.0]), breech presentation (11.3% versus 5%; p=0.3); however, the difference was not statistically significant in two groups. CONCLUSION: We concluded that pregnancy in women with uterine fibroids is a high-risk pregnancy and needs a particular follow-up.

The diagnostic accuracy of external pelvimetry and maternal height to predict dystocia in nulliparous women: a study in Cameroon.

OBJECTIVE: In many developing countries, most women deliver at home or in facilities without operative capability. Identification before labour of women at risk of dystocia and timely referral to a district hospital for delivery is one strategy to reduce maternal and perinatal mortality and morbidity. Our objective was to assess the prediction of dystocia by the combination of maternal height with external pelvimetry, and with foot length and symphysis-fundus height. DESIGN: A prospective cohort study. SETTING: Three maternity units in Yaoundé, Cameroon. POPULATION: A total of 807 consecutive nulliparous women at term who completed a trial of labour and delivered a single fetus in vertex presentation. METHODS: Anthropometric measurements were recorded at the antenatal visit by a researcher and concealed from the staff managing labour. After delivery, the accuracy of individual and combined measurements in the prediction of dystocia was analysed. MAIN OUTCOME MEASURES: Dystocia, defined as caesarean section for dystocia; vacuum or forceps delivery after a prolonged labour (>12 hours); or spontaneous delivery after a prolonged labour associated with intrapartum death. RESULTS: Ninety-eight women (12.1%) had dystocia. The combination of a maternal height less than or equal to the 5th percentile or a transverse diagonal of the Michaelis sacral rhomboid area less than or equal to the 10th percentile resulted in a sensitivity of 53.1% (95% CI 42.7-63.2), a specificity of 92.0% (95% CI 89.7-93.9), a positive predictive value of 47.7% (95% CI 38.0-57.5) and a positive likelihood ratio of 6.6 (95% CI 4.8-9.0), with 13.5% of all women presumed to be at risk. Other combinations resulted in inferior prediction. CONCLUSION: The combination of the maternal height with the transverse diagonal of the Michaelis sacral rhomboid area could identify, before labour, more than half of the cases of dystocia in nulliparous women.

Malaria vectors and transmission dynamics in coastal south-western Cameroon

Background: Malaria is a major public health problem in Cameroon. Unlike in the southern forested areas where the epidemiology of malaria has been better studied prior to the implementation of control activities; little is known about the distribution and role of anophelines in malaria transmission in the coastal areas. Methods: A 12-month longitudinal entomological survey was conducted in Tiko; Limbe and Idenau from August 2001 to July 2002. Mosquitoes captured indoors on human volunteers were identified morphologically. Species of the Anopheles gambiae complex were identified using the polymerase chain reaction (PCR). Mosquito infectivity was detected by the enzyme-linked immunosorbent assay and PCR. Malariometric indices (plasmodic index; gametocytic index; parasite species prevalence) were determined in three age groups (5yrs; 5-15yrs; 15yrs) and followed-up once every three months. Results: In all; 2;773 malaria vectors comprising Anopheles gambiae (78.2); Anopheles funestus (17.4) and Anopheles nili (7.4) were captured. Anopheles melas was not anthropophagic. Anopheles gambiae had the highest infection rates. There were 287; 160 and 149 infective bites/person/year in Tiko; Limbe and Idenau; respectively. Anopheles gambiae accounted for 72.7; An. funestus for 23and An. nili for 4.3of the transmission. The prevalence of malaria parasitaemia was 41.5in children 5 years of age; 31.5in those 5-15years and 10.5in those 15years; and Plasmodium falciparum was the predominant parasite species.Conclusions: Malaria transmission is perennial; rainfall dependent and An. melas does not contribute to transmission. These findings are important in the planning and implementation of malaria control activities in coastal Cameroon and West Africa

Methotrexate induces seizure and decreases glutamate uptake in brain slices: prevention by ionotropic glutamate receptors antagonists and adenosine.

Methotrexate (MTX)-induced neurotoxicity may occur after intrathecal or systemic administration at low, intermediate and high doses for the treatment of malignant or inflammatory diseases. The mechanisms of MTX neurotoxicity are not totally understood, and appear to be multifactorial. In this study we characterized a model of MTX-induced seizures in mice to evaluate the convulsive and toxic MTX properties. Additionally, the effect of MTX-induced seizures on the activity of glutamate transporters, as well as the anticonvulsant role of MK-801, DNQX and adenosine on glutamate uptake in brain slices was investigated . MTX induced tonic-clonic seizures in approximately 95% of animals and pre-treatment with MK-801, DNQX and adenosine prevented seizure in 80%, 62% and 50% of animals, respectively. Moreover, MTX leads 59% of mice to death, which was prevented in 100% and 94% when animals received MK-801 and DNQX, respectively. Glutamate uptake decreased by 20% to 30% in cortical slices after MTX-induced seizures. Interestingly, when seizures were prevented by MK-801, DNQX or adenosine, glutamate uptake activity remained at the same level as the control group. Thus, our results demonstrate the involvement of the glutamatergic system in MTX-induced seizures.

[Delivery outcome of adolescents in Far North Cameroon]. / Accouchement des adolescentes à l'Extrême Nord du Cameroun: des proportions inadmissibles!

UNLABELLED: Delivery in teenager is associated with increased risk. The aim of this study was to evaluate the contribution of teenagers (10-19 years or less) to the total number of deliveries over a 10 year period in the Maroua provincial hospital (Cameroon) This was a retrospective study. The deliveries of 3.328 teenagers were analysed as far as their contribution to the deliveries is concerned and how this contribution changed with time from 01/01/1995 to 31/12/2004 at the Provincial Hospital Maroua (Cameroon). Analyses were performed using Excel and Epi Info 6. The chietaiota2 tests of the tendency, taking in account all ten age groups, was used to appreciate the phenomenon over time. This trend was considered significant if p<0.05. RESULTS: During the study period 13.026 women delivered, 489 cases were excluded because the age was not specified. Finally, 3.328 teenagers were analysed out of a total of 12537 cases, as far as their contribution to the number of deliveries from 1995 to 2004 in the Maroua provincial hospital. Teenagers contributed for 26,54% of total deliveries in Maroua Provincial Hospital, (Cameroon). Teenagers of 16 and less contributed for 7,58%, and those aged 17 to 19 years contributed for 18,25%. We found out that the trend over the study period, has not changed (p>0.05). This study emphasizes the need of redynamisation of adolescents health services in Extreme North Cameroon. Studies should be done to determine the impact of young age on the delivery outcome.

Interactions between human immunodeficiency virus and herpes viruses within the oral mucosa.

There is evidence from clinical case reports and epidemiological studies that human immunodeficiency virus (HIV) can be transmitted through oral sex. Herpes viruses that appear in the oral mucosa might influence the oral replication of HIV. A review of data suggesting that interactions occur between HIV and herpes viruses indicates that such interactions might operate in the oral mucosa. Defining the mechanisms by which herpes viruses interact with HIV in the oral mucosa should permit intervention measures to be targeted more precisely.

Extensive multiple test centre evaluation of the VecTest malaria antigen panel assay.

To determine which species and populations of Anopheles transmit malaria in any given situation, immunological assays for malaria sporozoite antigen can replace traditional microscopical examination of freshly dissected Anopheles. We developed a wicking assay for use with mosquitoes that identifies the presence or absence of specific peptide epitopes of circumsporozoite (CS) protein of Plasmodium falciparum and two strains of Plasmodium vivax (variants 210 and 247). The resulting assay (VecTest Malaria) is a rapid, one-step procedure using a 'dipstick' test strip capable of detecting and distinguishing between P. falciparum and P. vivax infections in mosquitoes. The objective of the present study was to test the efficacy, sensitivity, stability and field-user acceptability of this wicking dipstick assay. In collaboration with 16 test centres world-wide, we evaluated more than 40 000 units of this assay, comparing it to the standard CS ELISA. The 'VecTest Malaria' was found to show 92% sensitivity and 98.1% specificity, with 97.8% accuracy overall. In accelerated storage tests, the dipsticks remained stable for > 15 weeks in dry conditions up to 45 degrees C and in humid conditions up to 37 degrees C. Evidently, this quick and easy dipstick test performs at an acceptable level of reliability and offers practical advantages for field workers needing to make rapid surveys of malaria vectors.

Gravidity-dependent production of antibodies that inhibit binding of Plasmodium falciparum-infected erythrocytes to placental chondroitin sulfate proteoglycan during pregnancy.

During pregnancy, Plasmodium falciparum-infected erythrocytes sequester in the placenta by adhering to chondroitin 4-sulfate, creating a risk factor for both the mother and the fetus. The primigravidae are at higher risk for placental malaria than the multigravidae. This difference in susceptibility has been attributed to the lack of antibodies that block the adhesion of infected erythrocytes to placental chondroitin 4-sulfate in primigravid women. However, recent results show that many primigravidae at term have antibody levels similar to those of multigravidae, and thus the significance of antiadhesion antibodies in providing protection against malaria during pregnancy remains unclear. In this study, we analyzed plasma samples from women of various gravidities at different gestational stages for antiadhesion antibodies. The majority of women, regardless of gravidity, had similar levels of antibodies at term. Most primigravidae had low levels of or no antiadhesion antibodies prior to ~20 weeks of pregnancy and then produced antibodies. Multigravidae also lacked antibodies until ~12 weeks of pregnancy, but thereafter they efficiently produced antibodies. In pregnant women who had placental infection at term, higher levels of antiadhesion antibodies correlated with lower levels of placental parasitemia. The difference in kinetics of antibody production between primigravidae and multigravidae correlated with the prevalence of malaria in these groups, suggesting that antibodies are produced during pregnancy in response to placental infection. The early onset of efficient antibody response in multigravidae and the delayed production to antibodies in primigravidae appear to account for the gravidity-dependent differential susceptibilities of pregnant women to placental malaria.

HLA-DR and -DQ polymorphism in Cameroon.

HLA-DRB1, -DQA1 and -DQB1 allele frequencies were determined by high-resolution polymerase chain reaction using sequence-specific oligonucleotide probes (PCR-SSOP) and/or DNA sequencing in 126 healthy individuals in Cameroon. Eighteen DRB1, 11 DQA1, and 18 DQB1 alleles were observed. The most common alleles at each locus were DRB1*1503 (29%), DRB1*1301 (13%); DQA1*0102 (38%), DQA1*0302 (11%), DQA1*0401 (11%); and DQB1*0602 (31%), DQB1*0301 (13%), DQB1*0501 (12%). Forty-four different haplotypes were identified including 12 novel haplotypes demonstrating the HLA class II diversity resulting from allele combinations in this population. A single predominant DRB1*1503-DQA1*0102-DQB1*0602 haplotype was observed with a frequency of 27%. In summary, this study of HLA class II polymorphism in Cameroon demonstrates the extent of diversity in this population.

The state of immunology in Africa: HIV/AIDS and malaria.

HIV and malaria are two major infections that are responsible for the greatest burden of diseases, morbidity and mortality in the African population. Successful research has been undertaken in Africa into novel means of monitoring HIV disease progression and in identifying vaccine candidates. The role of IgG isotypes in malaria has been investigated, as have parasite adhesion molecules important for pathogenesis. It is hoped that vaccines for malaria will soon prove successful. However, many problems still face immunology research in Africa.

Acquisition and decay of antibodies to pregnancy-associated variant antigens on the surface of Plasmodium falciparum-infected erythrocytes that protect against placental parasitemia.

Otherwise clinically immune women in areas endemic for malaria are highly susceptible to Plasmodium falciparum malaria during their first pregnancy. Pregnancy-associated malaria (PAM) is characterized by placental accumulation of infected erythrocytes that adhere to chondroitin sulfate A (CSA). Susceptibility to PAM decreases with increasing parity, apparently due to acquisition of antibodies directed against the variant surface antigens (VSAs) that mediate the adhesion to CSA (VSA(CSA)). This study found that levels of VSA(CSA)-specific antibodies depend on endemicity, that anti-VSA(CSA) IgG is acquired during gestation week 20, and that plasma levels of the antibodies decline during the postpartum period. There is evidence that VSA(CSA)-specific antibodies are linked to placental infection and that high antibody levels contribute to the control of placental infection by inhibiting parasite adhesion to CSA. Data suggest that VSA(CSA) is a target for vaccination against PAM.

Complications of induced abortion and miscarriage in three African countries: a hospital-based study among WHO collaborating centers.

OBJECTIVE: The aim of this study was to describe two of the outcomes of pregnancy, induced abortion and miscarriage, in three African countries. Major maternal risk factors were also evaluated. METHODS: The study was prospective and based on the medical files of all 1,957 women admitted to participating health care structures. RESULTS: Overall, 988 women were admitted for complications of miscarriage, and 969 for complications of induced abortion. Gestational age was lower in women with miscarriages (p<0.002). The level of use of contraceptive methods ((p<0.003) and educational level ((p<0.005) were lower in women who had had an induced abortion. In our study, 26 maternal deaths were recorded, 22 of which were associated with induced abortion. Infection was the most important risk factor for death (OR=4.8; 1.9-12.4). CONCLUSION: Maternal deaths related to abortion complications often occurred shortly after hospital admission and with signs of sepsis. This demonstrates the importance of effective emergency services. Unfortunately, hospital-based studies alone cannot assess all maternal death risk factors, especially those for maternal death related to induced abortion complications. It is therefore important to determine what happened to the woman before hospital admission and during her stay in hospital. Combinations of qualitative and quantitative methods could be used to increase our understanding of this problem and to help us to solve it.

Diversity is demonstrated in class I HLA-A and HLA-B alleles in Cameroon, Africa: description of HLA-A*03012, *2612, *3006 and HLA-B*1403, *4016, *4703.

To examine the genetic diversity in west Africa, class I HLA-A and HLA-B alleles of 92 unrelated individuals from two areas in the Cameroon, the capital Yaoundé and the village of Etoa, were identified by direct automated DNA sequencing of exons 2 and 3 of the HLA-B locus alleles and sequence-specific oligonucleotide probe (SSOP) and/or sequencing of the HLA-A locus alleles. HLA-A*2301 (18.7%), A*2902 (10.4%), B*5301 (10.9%), and B*5802 (10.9%) were the most frequently detected alleles, present in at least 10% of the population. A total of 30 HLA-A locus and 33 HLA-B locus alleles, including six novel alleles, were detected. The novel alleles were HLA-A*03012, A*2612, A*3006 and HLA-B*1403, B*4016, and B*4703. HLA-B*4703 contains a novel amino acid sequence that is a combination of the first 5 amino acids of the Bw6 epitope and the last 2 residues of the Bw4 epitope. The addition of 6 alleles to the ever-expanding number of known class I HLA alleles supports our hypothesis that extensive genetic diversity, including previously undescribed alleles, would be observed in this African population. In the Yaoundé population, the allele frequency distribution at the HLA-A locus is consistent with distributions indicative of balancing selection. Extensive HLA-A-B haplotypes were observed in this population suggesting that only a fraction of the Cameroon HLA-A-B haplotype diversity has been observed.