Effects of household composition on infant feeding and mother-infant health in northern Kenya.

BACKGROUND: Households with alloparents, individuals other than the mother who care for an infant, can shift members' roles and affect mother-infant health. AIMS: To investigate how household composition relates to infant feeding and infectious disease risk in mother-infant dyads, the team utilized data from breastfeeding dyads (n 208) surveyed during a prolonged drought and food scarcity in northern Kenya. METHODS: Households were classified by the presence/absence of potential alloparents, distinguishing non-siblings and siblings of the infant. Regression models for breastfeeding frequency, complementary feeding status, and recent infections (n 83) evaluated these outcomes' associations with household type while accounting for food insecurity, adjusted for infant age, infant sex, and maternal age. RESULTS: Household type was unassociated with breastfeeding frequency, but the presence of non-sibling alloparents interacted with food insecurity, predicting increasing breastfeeding frequency as food insecurity intensified among dyads living with non-sibling alloparents. Households with non-sibling alloparents were also inversely associated with complementary feeding but had no association with infection. Households with siblings were inversely associated with (protective against) infant and maternal infection. CONCLUSION: Further research is needed to understand the interactive influence of household social and food ecologies on mother-infant diet and health under diverse cultural rules and norms for alloparenting.

Ethnobotanical and antimicrobial studies of some plants used in Kibwezi (Kenya) for management of lower respiratory tract infections.

Respiratory tract infections have gained worldwide recognition especially due to the increased incidence of HIV/AIDS. The bacteria responsible for these infections have also become increasingly resistant to chemotherapeutic agents in lower respiratory infections in Kibwezi in Kenya. Interviews were conducted using semi-structured questionnaires and detailed discussions with respondents. During the field surveys direct observations were made on how these plants are used. From the ethnobotanical survey the modes of preparation used included chewing and boiling. The plant parts used were mostly bark and root, which implies that the main methods of harvesting these plants are destructive in nature. Water and methanolic extracts of the three most popular plants, Acacia nilotica, Strychnos heninngsii and Microglossa densiflora were tested against three test organism: Staphylococcus aureus, Streptococcus pneumoniae and Escherichia coli for their antimicrobial properties. The efficacy of the extracts was tested by bioassay method using the disk diffusion test. It was interesting to note that none of the tested water extracts showed any activity against the test organisms. This is despite the fact that about 83% of the local people used water for extraction. Methanolic extracts of Acacia nilotica and Strychnos heninningsii showed efficacy against S. aureus, S. pneumoniae and E. coli. The findings of this research indicate that A. nilotica and S. heninngsii have antimicrobial properties and further work especially using mammalian models is recommended.

Environmental and occupational exposure to lead.

OBJECTIVE: To determine the status of environmental and occupational lead exposure in selected areas in Nairobi, Kenya. DESIGN: Cross sectional study. SETTING: Kariobangi North, Babadogo, Waithaka and Pumwani for assessment of environmental exposure to lead (Pb) and Ziwani Jua Kali works for assessment of occupational lead exposure. Olkalou in Nyandarua District was the covariate study area. SUBJECTS: Three hundred and eight children and adults participated. RESULTS: Blood lead levels (BLLs) obtained for the entire sample (n = 308) ranged from 0.4 to 65 microg/dl of blood. One hundred and sixty nine (55%) of the total sample had levels equal to or below 4.9 microg/dl, while 62 (20%) of the sample had levels ranging from 5.0 to 9.9 microg/dl. Blood lead levels above 10 microg/dl were recorded in 77 (25%) of the total sample. Within Nairobi, 32 (15.3%) of the study subjects in areas meant for assessment of environmental lead exposure had levels above the WHO/CDC action levels of 10 microg/dl of blood. The mean BLL for the occupationally exposed (Ziwani Jua kali) was 22.6 +/- 13.4 microg/dl. Among the workers, 89% had BLLs above 10 microg/dl. In general, 15% of the entire sample (for both environmental and occupational groups) in Nairobi had BLLs above 15 microg/dl. The covariate group at Olkalou had a mean BLL of 1.3 +/- 0.9 microg/dl. CONCLUSION: The prevalence of environmental lead exposure to the general public is high in Nairobi compared to Olkalou where non exposure was reported. Occupational lead exposure has been identified to be at alarming levels and urgent intervention measures are recommended.

Novel tricyclic inhibitors of farnesyl protein transferase. Biochemical characterization and inhibition of Ras modification in transfected Cos cells.

Ras protooncogenes encode 21-kDa membrane-associated guanine nucleotide-binding proteins, which play a critical role in control of cellular proliferation and differentiation. Oncogenic, activated forms of Ras proteins are associated with a broad range of human cancers. The elucidation of the post-translational modifications that occur at the carboxyl terminus of Ras and the demonstration that farnesylation of Ras by farnesyl protein transferase is essential for Ras-induced cellular transformation has opened up a new and promising approach to the development of anti-Ras therapeutics. We report here a novel series of potent farnesyl protein transferase (FPT) inhibitors, represented by SCH 44342. This compound inhibits both rat brain and recombinant human FPT with an IC50 of approximately 250 nM, while it is only weakly active against rat brain geranylgeranyl protein transferase-1 (IC50 > 114 microM). FPT inhibition has been observed using both Ha-Ras protein and Ki-Ras-derived peptide substrates in two different assay formats. SCH 44342 and its analogs also inhibit farnesylation of Ras in Cos cells transiently expressing [Val12]Ha-Ras with IC50 values in the low micromolar range. At these concentrations they do not inhibit sterol biosynthesis or geranylgeranylation of protein. In addition, we observed that Cos cells undergo pronounced morphological changes upon overexpression of [Val12]activated forms of Ha-Ras containing COOH-terminal sequences allowing farnesylation (CVLS) or geranylgeranylation (CVLL) but not upon overexpression of activated Ras lacking the isoprenylated Cys (SVLS). Ras-induced morphological changes can be partially reverted with lovastatin. Importantly, SCH 44342 can block morphological changes induced by [Val12]Ha-Ras-CVLS but not [Val12]Ha-Ras-CVLL. Recently, a number of other FPT inhibitors have been reported. Most of the compounds reported to have cell-based activity are peptidomimetic analogs of the CAAX substrate. Our FPT inhibitors are novel in that although they compete with Ras protein in kinetic experiments they are entirely nonpeptidic in nature, they do not have oxidizable sulfhydryl functions, and they are active in cells at low micromolar concentrations.