Cellular immune responses against natural human papillomavirus infections among men in Kisumu, Kenya.

Human papillomavirus (HPV) is associated with ano-genital and cervical cancer. Persistence of oncogenic HPV genotypes is a requirement for development and progression of malignancies. Although, >70% of women clear incident HPV infections, data on natural history and HPV immunology among men is limited.

Hepatitis C virus genotypes in Kenya.

Hepatitis C virus is a great public-health concern worldwide. Phylogenetic analysis of the HCV genome has identified six different genotypes that have generally been divided into several subtypes. There is very little information on HCV seroprevalence and genotypes in Kenya.

High prevalence of Rickettsia africae variants in Amblyomma variegatum ticks from domestic mammals in rural western Kenya: implications for human health.

Tick-borne spotted fever group (SFG) rickettsioses are emerging human diseases caused by obligate intracellular Gram-negative bacteria of the genus Rickettsia. Despite being important causes of systemic febrile illnesses in travelers returning from sub-Saharan Africa, little is known about the reservoir hosts of these pathogens. We conducted surveys for rickettsiae in domestic animals and ticks in a rural setting in western Kenya.

HIV co-infection with tuberculous and non-tuberculous mycobacteria in western Kenya: challenges in the diagnosis and management.

Background: Tuberculosis (TB) and HIV co-infections have a global prevalence with devastating morbidity and massive mortality, Sub-Saharan Africa being the worst hit.

Objectives: To evaluate the prevalence of TB-HIV co-infection and demonstrate the confusion caused by NTM and HIV/AIDS co-infection in TB diagnosis and treatment in western Kenya.

Methods: In a cross-sectional study carried out at 10 hospitals in western Kenya, sputa from consenting 872 TB suspects underwent microscopy, and culture on Lowenstein-Jensen and Mycobacteria Growth Index Tube media.

Switch from 200 to 350 CD4 baseline count: what it means to HIV care and treatment programs in Kenya.

Introduction: With the increasing population of infected individuals in Africa and constrained resources for care and treatment, antiretroviral management continues to be an important public health challenge. Since the announcement of World Health Organization recommendation and guidelines for initiation of antiretroviral Treatment at CD4 count below 350, many developing countries are adopting this strategy in their country specific guidelines to care and treatment of HIV and AIDS. Despite the benefits to these recommendations, what does this switch from 200 to 350 CD4 count mean in antiretroviral treatment demand?

Methods: A Multi-centre study involving 1376 patients in health care settings in Kenya.

ZIEHL-NEELSEN MICROSCOPY IN THE DIAGNOSIS OF TUBERCULOSIS IN SETTINGS OF HIGH HUMAN IMMUNODEFICIENCY VIRUS PREVALENCE.

Objective: To determine the accuracy of Ziehl-Neelsen microscopy in the diagnosis of TB in setings of high HIV prevalence.

Design: Cross-sectional descriptive study.

Setting: Hospitals serving areas of high human immunodeficiency virus prevalence in western Kenya.

CRYPTOSPORIDIOSIS AND ITS GENOTYPES AMONG CHILDREN ATTENDING MOI TEACHING AND REFERRAL HOSPITAL IN ELDORET, KENYA.

Objectives: To determine the prevalence of cryptosporidiosis and the associated factors, and characterise the Cryptosporidium isolates from children aged five years and less with diarrhoea.

Design: A prospective cross-sectional study.

Setting: This was a health facility and laboratory based study.

CD26/dipeptidyl peptidase IV (CD26/DPPIV) is highly expressed in peripheral blood of HIV-1 exposed uninfected female sex workers.

Background: Design of effective vaccines against the human immunodeficiency virus (HIV-1) continues to present formidable challenges. However, individuals who are exposed HIV-1 but do not get infected may reveal correlates of protection that may inform on effective vaccine design. A preliminary gene expression analysis of HIV resistant female sex workers (HIV-R) suggested a high expression CD26/DPPIV gene.

Survey on prevalence and risk factors on HIV-1 among pregnant women in North-Rift, Kenya: a hospital based cross-sectional study conducted between 2005 and 2006.

Background: The HIV/AIDS epidemic in Kenya is a major public-health problem. Estimating the prevalence of HIV in pregnant women provides essential information for an effective implementation of HIV/AIDS control measures and monitoring of HIV spread within a country. The objective of this study was to determine the prevalence of HIV infection, risk factors for HIV/AIDS and immunologic (lymphocyte profile) characteristics among pregnant women attending antenatal clinics in three district hospitals in North-Rift, Kenya.

Molecular genetic diversity of hepatitis B virus in Kenya.

Eight genotypes of hepatitis B virus (A-H) and subgenotypes have been recognized worldwide. However, there is limited information on prevalent genotypes in many countries in Africa. This study was undertaken to determine the hepatitis B virus (HBV) genotypes in Kenya.

Molecular technique utilising sputum for detecting Wuchereria bancrofti infections in Malindi, Kenya.

Background: Lymphatic filariasis is a tropical parasitic disease which has been identified for elimination by 2020 through mass drugs administration. There is a major problem in its diagnosis and sensitive surveillance methods for monitoring the disease elimination programs need to be sought.

Objectives: To establish and evaluate the usefulness of a Polymerase Chain Reaction, PCR assay employing sputum for diagnosis of Wuchereria bancrofti infections in an endemic location.

Tuberculosis and oral Candida species surveillance in HIV infected individuals in Northern Kenya, and the implications on tuberculin skin test screening for DOPT-P.

Objective: To determine the pattern of opportunistic infections such as TB and Candida species in HIV infected patients in Northern Kenya.

Design: Cross-sectional study.

Setting: Five health facilities in Moyale (n=224), Mandera (n=121) and Turkana Kakuma; (n=83), Lopiding; (n=94) districts during different periods in 2003.

HIV type 1 subtypes in circulation in northern Kenya.

The genetic subtypes of HIV-1 circulating in northern Kenya have not been characterized. Here we report the partial sequencing and analysis of samples collected in the years 2003 and 2004 from 72 HIV-1-positive patients in northern Kenya, which borders Ethiopia, Somalia, and Sudan. From the analysis of partial env sequences, it was determined that 50% were subtype A, 39% subtype C, and 11% subtype D.

CD4T lymphocyte subsets and disease manifestation in children with and without HIV born to HIV-1 infected mothers.

Objective: To understand the natural history of HIV-1 infection in children in terms of evolution of childhood clinical manifestations versus the immune status, we prospectively studied children with and without maternally transmitted HIV-1 infection born to mothers infected with HIV-1 for two years between March 1998 and March 2000.

Design: A prospective cohort study.

Setting: An institutional children's home.

New indirect immunofluorescence assay as a confirmatory test for human immunodeficiency virus type 1.

Background: Screening of blood and blood products for human immunodeficiency virus (HIV) is routinely performed using the enzyme-linked immunosorbent assay (ELISA), and the results confirmed by Western blot (WB). However, western blot is expensive and mostly performed in developed countries. A technique more superior or comparable to WB and adaptable to developing countries must be sought.

Mitochondrial DNA control region sequences from Nairobi (Kenya): inferring phylogenetic parameters for the establishment of a forensic database.

Large forensic mtDNA databases which adhere to strict guidelines for generation and maintenance, are not available for many populations outside of the United States and western Europe. We have established a high quality mtDNA control region sequence database for urban Nairobi as both a reference database for forensic investigations, and as a tool to examine the genetic variation of Kenyan sequences in the context of known African variation. The Nairobi sequences exhibited high variation and a low random match probability, indicating utility for forensic testing.

Leishmania major-Phlebotomus duboscqi interactions: inhibition of anti-LPG antibodies and characterisation of two proteins with shared epitopes.

Objectives: To assess the effect of monoclonal antibodies (MABS) raised against L. major derived LPG on L. major development in vitro and in its natural vector P.

Leishmania donovani-derived lipophosphoglycan plus BCG induces a Th1 type immune response but does not protect Syrian golden hamsters (Mesocricetus auratus) and BALB/c mice against Leishmania donovani.

The efficacy of Leishmania donovani-derived lipophosphoglycan (LPG) plus Mycobacterium bovis Bacille Calmette-Guerin (BCG) as a vaccine candidate against visceral leishmaniosis in susceptible BALB/c mouse and Syrian golden hamster (Mesocricetus auratus) models was investigated. Following a triple vaccination with a total dose of 150 microl BCG plus 60 microg or 30 microg of LPG for hamsters and BALB/c mice respectively, there were no noticeable side effects both locally and systemically; implying that the molecule was safe at this dosage level. Vaccinated animals demonstrated an activation of both the humoral as well as cell-mediated responses to LPG, which correlated with resistance against the disease.

The use of short-course zidovudine to prevent perinatal transmission of human immunodeficiency virus in rural Kenya.

To determine the feasibility of using short-course zidovudine (ZDV) to prevent mother-to-child transmission of human immunodeficiency virus (HIV) in a breastfeeding population in a rural area in Kenya, pregnant mothers attending clinics in seven health centers in western Kenya between 1996 and 1998 were requested to volunteer for participation in this study. The HIV-infected mothers were given a daily dose of 400 mg of ZDV starting at 36 weeks of gestation and another 300 mg every three hours intrapartum. After delivery, mothers and their children were followed-up and clinically monitored every 3-4 months for two years, and child and mother mortality rates were analyzed.

Maternal immune responses and risk of infant infection with HIV-1 after a short course Zidovudine in a cohort of HIV-1 infected pregnant women in rural Kenya.

Objective: To investigate the effects of short-course nucleoside reverse transcriptase inhibitor (Zidovudine, ZDW/AZT) on maternal immune responses and risk of infant infection with HIV-1 among rural-based mothers in western Kenya.

Design: A prospective cohort study involving HIV-1 seropositive pregnant mothers and their infants.

Subjects: One hundred and seven HIV-1 seropositive asymptomatic pregnant women and their infants.

Rational design of novel antimicrobials: blocking purine salvage in a parasitic protozoan.

All parasitic protozoa obtain purine nucleotides solely by salvaging purine bases and/or nucleosides from their host. This observation suggests that inhibiting purine salvage may be a good way of killing these organisms. To explore this idea, we attempted to block the purine salvage pathway of the parasitic protozoan Tritrichomonas foetus.

Differential staining of apoptotic nuclei in living cells: application to macronuclear elimination in Tetrahymena.

Acridine orange (AO) has been used as a vital fluorescent stain to identify apoptotic cells in Drosophila, but little is known about what structures are stained. We explored the specificity of AO staining while studying nuclear apoptosis in Tetrahymena. Using AO alone or together with the vital nuclear stain Hoechst 33342 (HO), we find that lysosomes are generally clustered around the degenerating nucleus and that such nuclei are stained an orange-red color, like lysosomes.

DNA digestion and chromatin condensation during nuclear death in Tetrahymena.

DNA fragmentation and nuclear condensation are key features in the regulated cell death of higher animal cells. Nuclear death also occurs as part of a developmentally programmed process during the sexual life cycle of the unicellular organism Tetrahymena. We examined the regulation of nuclear death and the relationship between DNA fragmentation and chromatin condensation in this model system.

Phosphorylated and dephosphorylated linker histone H1 reside in distinct chromatin domains in Tetrahymena macronuclei.

Phosphorylated and dephosphorylated isoforms of Tetrahymena macronuclear H1 were separated from each other by cation-exchange high performance liquid chromatography and used to generate a pairwise set of antisera that discriminate the phosphorylation state of this linker histone. Affinity-purified antibodies from each sera recognize appropriate H1 isoforms and stain macronuclei under appropriate physiological conditions. Immunogold localizations demonstrate that phosphorylated and dephosphorylated H1 localize nonrandomly in distinct subdomains of macronuclear chromatin.