Familial and socioeconomic influences on children''s well-being: An examination of preschool children in Kenya

As patterns of family formation change, it is important to know how children's lives are affected by their parents' marital and socioeconomic circumstances. Using data from the 1993 Kenya Demographic and Health Survey, this study shows that children of never married and formerly married mothers have significantly higher probabilities of polio dropout and acute undernutrition than those of monogamously married mothers. The number of male household members of working age greatly enhances the chances of full immunization and the nutritional status of children whose mothers were previously married. For children of never married mothers, the benefits of residing with males of working age are largely a function of ethnicity. The results also show that, although children are not disadvantaged nutritionally when their fathers have more than one wife, polygyny is associated with a higher probability of polio dropout and lower probability of full immunization than monogamy. Higher socioeconomic status is associated with a greater probability of full immunization and a lower probability of malnutrition but socioeconomic factors do not explain the effects of mothers' marital status. The findings underscore the complex realities of family interaction and the importance of the broader social context in accounting for variations in child welfare across diverse marital situations.     

Experimental quantiles of epidemiological indices in case-control studies with non-differential misclassification

The formulae for some typical epidemiological indices in case-control studies with non-differential misclassification are expressed in terms of two groups (α, β) and (γ, δ) of misclassification probabilities of exposure E and confounder C, respectively, and the initially estimated frequencies. The parameters α and β denote the probability that subjects exposed to E are classified as non-exposed and the probability that non-exposed ones will be classified as exposed, respectively. Similarly, δ and γ stand for the probability that those who have been exposed to C will be classified as non-exposed and the probability that non-exposed subjects are classified as exposed, respectively. The non-negativeness of the expressions for the ‘true’ frequencies in terms of the measured ones and the misclassification probabilities leads to the construction of feasibility regions for α, β, γ and δ. For a number of ‘acceptable’ 4-tuples (α, β, γ, δ), all of which lie inside these feasibility regions, a sequence of feasible values for an epidemiological index is determined, after employing a systematic procedure by means of a ‘searching net’ with increments Δα, Δβ, Δγ, Δδ. The procedure serves to determine the characteristics of the (experimental) cumulative distribution function for any selected epidemiological index. The final stage in exploiting the structure of feasibility regions for α, β, γ and δ is to use the cumulative distribution function to calculate quantiles for the index associated with prescribed probabilities.     

Diagnosing osteoporosis by using dental panoramic radiographs: the OSTEODENT project.

OBJECTIVES: Measurement of cortical thickness and subjective assessment of cortical porosity on panoramic radiographs are methods previously reported for diagnosing osteoporosis. The aims of this study were to determine the relative efficacy of the mandibular cortical index and cortical width in detecting osteoporosis, both alone and in combination, and to determine the optimal cortical width threshold for referral for additional osteoporosis investigation. STUDY DESIGN: Six hundred seventy-one postmenopausal women 45 to 70 years of age were recruited for this study. They received dual energy x-ray absorptiometry (DXA) scans of the left hip and lumbar spine (L1 to L4), and dental panoramic radiographic examinations of the teeth and jaws. Three observers separately assessed the mandibular cortical width and porosity in the mental foramen region of the mandible. Cortical width was corrected for magnification errors. Chi-squared automatic interaction detection analysis (CHAID) software was used (SPSS AnswerTree, version 3.1, SPSS Inc., Chicago, IL). RESULTS: Chi-squared automatic interaction detection analysis showed that the cortical porosity was a poorer predictor of osteoporosis than mandibular cortical width. For the 3 observers, a mandibular cortical width of <3 mm provided diagnostic odds ratios of 6.51, 6.09, and 8.04. The test is therefore only recommended in triage screening of individuals by using radiographs made for purposes other than osteoporosis. CONCLUSION: When evaluating panoramic radiographs, only those patients with the thinnest mandibular cortices (i.e., <3 mm) should be referred for further osteoporosis investigation.     

Comparative analysis of environmental and clinical populations of Cryptococcus neoformans

Cryptococcus neoformans is a major, global cause of meningoencephalitis in immunocompromised patients. Despite advances in the molecular epidemiology of C. neoformans, its population structure and mode of reproduction are not well understood. In the environment, it is associated with avian guano or vegetation. We collected nearly 800 environmental isolates from three locations in the United States (viz., North Carolina, California, and Texas) and compared them with one another and with clinical isolates from North Carolina. As expected, they consisted of the most prevalent serotypes, serotypes A and D, as well as serotype AD hybrids. The majority of environmental isolates were obtained from pigeon excreta. All environmental and clinical isolates of serotype A or D had the MATalpha mating-type allele. However, the AD hybrids included MATa alleles typical of serotypes A and D. Using an amplified fragment length polymorphism fingerprinting technique with two primer pairs, we identified 12 genotypes among the isolates of serotype A. Six of these genotypes were present in both the clinical and the environmental populations. However, one of the most prevalent environmental genotypes was absent from the clinical samples, and two other genotypes were isolated only from patients. The combined molecular data suggest that this environmental population of C. neoformans is predominantly clonal, although there was evidence for recent or past recombination.     

Tumor Necrosis Factor Alpha Enhances Antifungal Activities of Polymorphonuclear and Mononuclear Phagocytes against Aspergillus fumigatus

Invasive aspergillosis is a serious complication in immunocompromised patients. The effects of recombinant human tumor necrosis factor alpha (TNF-α) on antifungal activities of human neutrophils (polymorphonuclear leukocytes [PMNs]), human monocytes (MNCs), and rabbit pulmonary alveolar macrophages (PAMs) against Aspergillus fumigatus were studied. The percentage of PMN-induced hyphal damage was increased after 30 min of incubation of PMNs with 0.1 ng of TNF-α per ml at 37°C (P = 0.043). At 0.1 to 10 ng/ml, TNF-α also increased superoxide anion (O₂⁻) produced by PMNs in response to phorbol myristate acetate, N-formylmethionyl leucyl phenylalanine, and unopsonized hyphae (P < 0.01) but did not exert any effect on PMN phagocytosis of conidia in the presence of serum. By comparison, TNF-α induced only a slight increase in O₂⁻ production by MNCs in response to phorbol myristate acetate (P = 0.05) and no concomitant increase in the percentage of MNC-induced hyphal damage. Incubation of MNCs with TNF-α at 0.001 to 10 ng/ml for 2 days had no effect on phagocytosis or conidiocidal activity. By contrast, incubation of PAMs with TNF-α at 0.1 to 10 ng/ml for 2 days increased phagocytosis of conidia (P = 0.03). Thus, TNF-α augments the capacity of PMNs to damage Aspergillus hyphae, possibly through enhanced oxidative mechanisms, and increases PAM phagocytic activity against conidia. As such, TNF-α may have an important role in host defense against aspergillosis, and neutralization of its activity may be complicated by increased susceptibility to aspergillosis.     

Molecular and phenotypic analysis of the CS54 island of Salmonella enterica serotype typhimurium: identification of intestinal colonization and persistence determinants

The shdA gene is carried on a 25-kb genetic island at centisome 54 (CS54 island) of the Salmonella enterica serotype Typhimurium chromosome. In addition to shdA, the CS54 island of Salmonella serotype Typhimurium strain LT2 contains four open reading frames designated ratA, ratB, sivI, and sivH. DNA hybridization analysis revealed that the CS54 island is comprised of two regions with distinct phylogenetic distribution within the genus SALMONELLA: Homologues of shdA and ratB were detected only in serotypes of Salmonella enterica subsp. I. In contrast, sequences hybridizing with ratA, sivI, and sivH were present in S. enterica subsp. II and S. bongori in addition to S. enterica subsp. I. Deletion of the ratA and sivI genes did not alter the ability of Salmonella serotype Typhimurium to colonize the organs of mice. Insertional inactivation of the sivH gene resulted in defective colonization of the Peyer's patches of the terminal ileum but normal colonization of the cecum, mesenteric lymph nodes, and spleen. Deletion of the shdA gene resulted in decreased colonization of the cecum and Peyer's patches of the terminal ileum and colonization to a lesser degree in the mesenteric lymph nodes and spleen 5 days post-oral inoculation of mice. A strain containing a deletion in the ratB gene exhibited a defect for the colonization of the cecum but not of the Peyer's patches, mesenteric lymph nodes, and spleen. The shdA and ratB deletion strains exhibited a shedding defect in mice, whereas the sivH deletion strain was shed at numbers similar to the wild type. These data suggest that colonization of the murine cecum is required for efficient fecal shedding in mice.