SUMMARYA procedure for the regeneration of cacao (Theobroma cacao) plants from staminode explants via somatic embryogenesis was developed. Rapidly growing calli were induced by culturing staminode explants on a DKW salts-based primary callus growth (PCG) medium supplemented with 20 g glucose per L, 9 ~M 2,4-D, and thidiazuron (TDZ) at various concentrations. Calli were subcultured onto a WPM salts-based secondary callus growth medium supplemented with 20 g glucose per L, 9 ltM 2,4-D, and 1.4 nM kinetin. Somatic embryos were formed from embryogenic calli following transfer to a hormonefree DKW salts-based embryo development medium containing sucrose. The concentration of TDZ used in PCG medium significantly affected the rate of callus growth, the frequency of embryogenesis, and the number of somatic embryos produced from each responsive explant. A TDZ concentration of 22.7 nM was found to be the optimal concentration for effective induction of somatic embryos from various cacao genotypes. Using this procedure, we recovered somatic embryos from all 19 tested cacao genotypes, representing three major genetic group types. However, among these genotypes, a wide range of variation was observed in both the frequency of embryogenesis, which ranged from 1 to 100%, and the average number of somatic embryos produced from each responsive explant, which ranged from 2 to 46. Two types of somatic embryos were identified on the hasis cff their visual appearance and growth behavior. A large number of cacao plants have been regenerated from somatic embryos and established in soil in a greenhouse. Plants showed morphological and growth characteristics similar to those of seed-derived plants. The described procedure may allow for the practical use of somatic embryogenesis for clonal propagation of elite cacao clones and other applications that require the production of a large number of plants from limited source materials.
the term "hygiene practices". Programmes which aim to improve these will have to focus on a small number of behaviours. These targeted behaviours will have to be chosen on the basis of their prevalence in the community, their amenability to change, and the epidemiological evidence of their impact on diarrhoea rates. Some evidence of links between behaviours surrounding stool disposal and childhood diarrhoea is now beginning to emerge, particularly from three studies from Asia."6In an urban setting in West Africa, we carried out a study to identify interventions that might reduce early childhood morbidity from diarrhoea using a wide range of techniques. In this paper we present that component of the study which concerned the association between child defecation behaviour, mothers' stool disposal practices, visible faecal contamination of the environment, and the rate of admission to hospital of young children with symptoms of diarrhoea or dysentery, or both. Other findings from the study, including detailed descriptions of the setting and of mothers' beliefs and practices regarding diarrhoea and stool hygiene, have been presented
The role of the Th1 pathway in the pathogenesis of severe malaria is unclear. We recently reported that a polymorphism with increasing IFNG transcription is associated with protection against cerebral malaria (CM). Interleukin-12 is required for Th1 cell differentiation, which is characterized by the production of interferon-gamma. We investigated 21 markers in IL12-related genes, including IL12A and IL12B encoding the two IL-12 (IL12p70) subunits, IL12p35 and IL12p40. We performed a family-based association study using a total sample set of 240 nuclear families. The IL12Bpro polymorphism was associated with susceptibility to CM. The CTCTAA allele and the GC/CTCTAA genotype are over-transmitted to children with CM (P = 0.0002 and 0.00002, respectively). We estimated the odds ratio to be 2.11 for risk of CM in heterozygous children [(95% confidence interval, 1.49-2.99); P < 0.0001]. Although the CTCTAA allele had a dominant effect on CM susceptibility, this effect is much stronger in heterozygous children, consistent with the functional effects of this allele in a heterozygous form. Heterozygosity for this polymorphism has been associated with reduced expression of the gene encoding IL12p40 and a low level of IL12p70 production. These results, together with the findings from immunological studies of low interferon-gamma and IL-12 levels in CM, support a protective role for the Th1 pathway in CM.
Summary:Purpose: Cerebral malaria (CM) is suspected to be a potential cause of epilepsy in tropical areas, but little information is available. The purpose of this study was to evaluate the role of CM in epilepsy among children in Mali.Methods: An exposed-nonexposed study was performed to identify children who had epilepsy after malaria in the 0-to 15-year age group. The exposure factor was CM defined according to World Health Organization (WHO) criteria, and the nonexposure factor was symptomatic malaria without the characteristics of CM (NCM). All the children underwent a screening questionnaire and were examined by a medical physician. After the screening phase, a specialist in neuropediatrics examined the children suspected to have epilepsy. EEG and computed tomography (CT) scans were performed in some of these patients.Results: In total, 101 subjects who had had CM and 222 who had had NCM were included. Fifty-four children (CM,34; NCM,20) were suspected to have epilepsy, and six were confirmed (CM, five; NCM, one). The incidence rate was 17.0 per 1000 person-years in the CM group and 1.8 per 1000 person-year in the NCM group; thus the relative risk (RR) was 9.4 [95% confidence interval (CI), 1.3-80.3; p = 0.02]. After adjustment on age and duration of follow-up, the RR was 14.3 (95% CI, 1.6-132.0; p = 0.01).Conclusions: The risk of sequelar epilepsy is significantly higher in the CM group compared with the NCM group. A reevaluation of this cohort should be carried out later to search for temporal epilepsy that appeared after age 10 years.
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