Association Between Glucan Synthesis by Streptococcus mutans and Caries Incidence in Schoolchildren Receiving a Fluoride Mouth Rinse

Purpose: To determine whether variation in glucan synthesis by Streptococcus mutans isolates is associated with caries development in children receiving a fluoride mouth rinse (FMR). Materials and Methods: Of 122 children (aged 9 to 10 years), 64 had received FMR (FMR(+) group) and the remaining 58 children had not (FMR(-) group). The number of decayed and filled teeth (DFT) and increases in the number of DFT in 1 year (dDFT) were recorded. Saliva samples were collected to isolate the clinical S. mutans strains. The isolates were incubated in heart infusion broth supplemented with 1% sucrose, then the amount of water-insoluble glucan (WIG) formed on a glass tube surface was evaluated. Results: In the FMR(-) group, children carrying S. mutans had a higher DFT (P = 0.039) and tended to have a higher dDFT (P = 0.080) than the others. In the FMR(+) group, although the differences between children with and without S. mutans were not significant, children carrying S. mutans that produced a high amount of WIG had higher dDFT than the other S. mutans-positive children (P = 0.034). Conclusions: This study revealed that the variation in glucan synthesis by S. mutans is associated with caries development in children receiving a FMR.     

Naratriptan: biological profile in animal models relevant to migraine

The biological profile of naratriptan (N-methyl-3-(1-methyl-4-piperidinyl)-1H-indole-5-ethane-sulphona-mide), a novel 5HT_1B/1D receptor agonist, was investigated in a variety of experimental models of relevance to migraine. Naratriptan has high affinity for human recombinant 5HT_1B and 5HT_1D receptors (pKi = 8.70.03 and 8.30.1, respectively) and causes contractions of dog isolated basilar and middle cerebral artery (EC₅₀ values of 0.11 and 0.07 M, respectively). Naratriptan causes small contractions of human isolated coronary arteries (EC₅₀ value of 0.17 M; maximum contraction equivalent to 33% of 5HT maximum). In anaesthetized dogs, naratriptan causes selective vasoconstriction of the carotid arterial bed (CD₅₀ dose = 193 g kg⁻¹) and, in anaesthetized rats, naratriptan selectively inhibits neurogenic plasma protein extravasation in the dura (ID₅₀ = 4.1 g kg⁻¹). In a variety of antinociceptive tests, naratriptan has no effect even at high doses. In conscious rats and dogs, naratriptan has high oral bioavailability (71% and 95%, respectively). The data show that naratriptan is a selective agonist at 5HT_1B/1D receptors, with a pharmacological profile very similar to that of sumatriptan, albeit 2-3 fold more potent. These observations, coupled with high oral bioavailability in animals, suggest that naratriptan has the profile of an orally effective anti-migraine drug.     

Allergen-specific Th1 cells fail to counterbalance Th2 cell–induced airway hyperreactivity but cause severe airway inflammation

Allergic asthma, which is present in as many as 10% of individuals in industrialized nations, is characterized by chronic airway inflammation and hyperreactivity induced by allergen-specific Th2 cells secreting interleukin-4 (IL-4) and IL-5. Because Th1 cells antagonize Th2 cell functions, it has been proposed that immune deviation toward Th1 can protect against asthma and allergies. Using an adoptive transfer system, we assessed the roles of Th1, Th2, and Th0 cells in a mouse model of asthma and examined the capacity of Th1 cells to counterbalance the proasthmatic effects of Th2 cells. Th1, Th2, and Th0 lines were generated from ovalbumin (OVA)-specific T-cell receptor (TCR) transgenic mice and transferred into lymphocyte-deficient, OVA-treated severe combined immunodeficiency (SCID) mice. OVA-specific Th2 and Th0 cells induced significant airway hyperreactivity and inflammation. Surprisingly, Th1 cells did not attenuate Th2 cell–induced airway hyperreactivity and inflammation in either SCID mice or in OVA-immunized immunocompetent BALB/c mice, but rather caused severe airway inflammation. These results indicate that antigen-specific Th1 cells may not protect or prevent Th2-mediated allergic disease, but rather may cause acute lung pathology. These findings have significant implications with regard to current therapeutic goals in asthma and allergy and suggest that conversion of Th2-dominated allergic inflammatory responses into Th1-dominated responses may lead to further problems.     

DWnt4 regulates the dorsoventral specificity of retinal projections in the Drosophila melanogaster visual system

In Drosophila melanogaster, the axons of retinal photoreceptor cells extend to the first optic ganglion, the lamina, forming a topographic representation. Here we show that DWnt4, a secreted protein of the Wnt family, is the ventral cue for the lamina. In DWnt4 mutants, ventral retinal axons misprojected to the dorsal lamina. DWnt4 was normally expressed in the ventral half of the developing lamina and DWnt4 protein was detected along ventral retinal axons. Dfrizzled2 and dishevelled, respectively, encode a receptor and a signaling molecule required for Wnt signaling. Mutations in both genes caused DWnt4-like defects, and both genes were autonomously required in the retina, suggesting a direct role of DWnt4 in retinal axon guidance. In contrast, iroquois homeobox genes are the dorsal cues for the retina. Dorsal axons accumulated DWnt4 and misprojected to the ventral lamina in iroquois mutants; the phenotype was suppressed in iroquois Dfrizzled2 mutants, suggesting that iroquois may attenuate the competence of Dfrizzled2 to respond to DWnt4.     

Food label reading and understanding in parts of rural and urban Zimbabwe

Background

Overweight and obesity prevalence is rapidly rising in developing countries. The reading and understanding of nutrition information on food packages has been shown to improve food choices and instill healthy eating habits in individuals.

Objective

The aim of this study was to describe the prevalence of food label usage and understanding among urban and rural adults in Zimbabwe and its association with demographic and socio economic factors.

Methods

A cross sectional study was conducted on 320 adults (147 urban and 173 rural) using a validated questionnaire adapted from previous similar studies. Data were analysed using SPSS-17 statistical software.

Results

A high proportion (77.2%) of the respondents read food labels. Food label reading differed significantly by educational status (p<0.05), employment status (p<0.05) and locality (p<0.05). Only 40.9% of food label readers mostly understood the information on the food labels. More urban shoppers (86.1%) read food labels than their rural counterparts (66.7%). A significant number of participants (80.6%) indicated they would like to be educated on the meaning of food labels and 80.3% preferred the nutrition information on food labels to be simplified.

Conclusion

The study found above average reported reading of nutrition information on food labels with partial understanding. Efforts should be made to determine how all consumers could be made to understand the nutrition information on food labels and use it effectively in decision making.