Factors increasing the caries risk of second primary molars in 5‐year‐old Dutch children

International Journal of Paediatric Dentistry 2010; 20: 151–157 Background. Caries is still a prevalent condition in 5‐year‐old children. At present, knowledge regarding some aetiological factors, like deciduous molar hypomineralization (DMH), is limited. Aim. To investigate aetiological factors both directly and indirectly associated with caries in second primary molars. Design. Of 974 children invited to participate in the study, 386 children were examined clinically with visual detection of caries. Only carious lesions determined to have reached the dentine were recorded. Information about tooth brushing frequency, education level of the mother, and country of birth of mother and child, was collected by means of a multiple‐choice questionnaire. Parents of 452 children filled in the questionnaire. Complete clinical and questionnaire data were available for 242 children. Statistical analysis of the effect of the independent variables was undertaken using the Pearson’s chi‐squared test. Results. Deciduous molar hypomineralization (P = 0.02) and the country of birth of the mother (P < 0.001) were positively associated with caries prevalence. Conclusions. Deciduous molar hypomineralization and the country of birth of the mother play a role in the prevalence of dental caries. These aetiological factors associated with childhood dental caries need to be investigated further in longitudinal clinical trials.     

Developing a spatial-statistical model and map of historical malaria prevalence in Botswana using a staged variable selection procedure

Background  

Several malaria risk maps have been developed in recent years, many from the prevalence of infection data collated by the MARA (Mapping Malaria Risk in Africa) project, and using various environmental data sets as predictors. Variable selection is a major obstacle due to analytical problems caused by over-fitting, confounding and non-independence in the data. Testing and comparing every combination of explanatory variables in a Bayesian spatial framework remains unfeasible for most researchers. The aim of this study was to develop a malaria risk map using a systematic and practicable variable selection process for spatial analysis and mapping of historical malaria risk in Botswana.     

Expression of prestin-homologous solute carrier (SLC26) in auditory organs of nonmammalian vertebrates and insects

Prestin, the fifth member of the anion transporter family SLC26, is the outer hair cell molecular motor thought to be responsible for active mechanical amplification in the mammalian cochlea. Active amplification is present in a variety of other auditory systems, yet the prevailing view is that prestin is a motor molecule unique to mammalian ears. Here we identify prestin-related SLC26 proteins that are expressed in the auditory organs of nonmammalian vertebrates and insects. Sequence comparisons revealed the presence of SLC26 proteins in fish (Danio, GenBank accession no. AY278118, and Anguilla, GenBank accession no. BAC16761), mosquitoes (Anopheles, GenBank accession nos. EAA07232 and EAA07052), and flies (Drosophila, GenBank accession no. AAF49285). The fly and zebrafish homologues were cloned and, by using in situ hybridization, shown to be expressed in the auditory organs. In mosquitoes, in turn, the expression of prestin homologues was demonstrated for the auditory organ by using highly specific riboprobes against rat prestin. We conclude that prestin-related SLC26 proteins are widespread, possibly ancestral, constituents of auditory organs and are likely to serve salient roles in mammals and across taxa.     

Radio-frequency tumor ablation: internally cooled electrode versus saline-enhanced technique in an aggressive rabbit tumor model

PURPOSE: To compare two methods of radio-frequency (RF) ablation, saline enhancement technique and internally cooled electrodes, for the treatment of small breast cancers in an animal model--highly aggressive VX2 rabbit tumors surrounded by adipose tissue. MATERIALS AND METHODS: Twenty-seven tumors were implanted into retroperitoneal fat of 14 New Zealand White rabbits. RF ablation was performed with ultrasonographic (US) guidance after tumors had grown to 15 mm. Fourteen tumors in seven animals were treated with internally cooled electrodes (30-mm-tip single electrode, 60 W, 10 min); 13 tumors in seven animals, with saline enhancement (0.5 mL/min of saline, 25-mm tip, 30 W, 10 min). Autopsy and histopathologic assessment were performed 3 weeks after therapy. RESULTS: Real-time US of RF ablation was not possible with either method because of obscuration by the increasing hyperechogenicity of the tumor and the surrounding adipose tissue. Equivalent efficacy was demonstrated with the two methods. Significantly greater complications were observed with the saline technique: Free retroperitoneal fluid was detected in one of seven animals with internally cooled electrodes and in all seven animals with saline enhancement (P <.01). Damage to remote structures such as the kidney, spine muscle, and skin was observed at autopsy in one of seven animals with internally cooled technique versus five of seven with saline enhancement (P <.01). CONCLUSION: Given a lower complication rate and similar treatment efficacy in an animal tumor model, internally cooled RF electrode may be advantageous to adjuvant saline infusion for the minimally invasive treatment of breast tumors.     

Pharmacokinetics of anthocyanidin-3-glycosides following consumption of Hibiscus sabdariffa L. extract

Pharmacokinetic parameters of several dietary anthocyanins following consumption of Hibiscus sabdariffa L. extract were determined in 6 healthy volunteers. Subjects were given a single oral dose of 150 mL of Hibiscus sabdariffa L. extract yielding 62.6 mg of cyanidin-3-sambubioside, 81.6 mg of delphindin-3-sambubioside, and 147.4 mg of total anthocyanins (calculated as cyanidin equivalents). Within 7 hours, the urinary excretion of cyanidin-3-sambubioside, delphinidin-3-sambubioside, and total anthocyanins (ie, the sum of all quantifiable anthocyanidin glycosides) was 0.016%, 0.021%, and 0.018% of the administered doses, respectively. Maximum excretion rates were determined at 1.5 to 2.0 hours after intake. The dose-normalized plasma area under the curve estimates were 0.076, 0.032, and 0.050 ng x h/mL/mg for cyanidin-3-sambubioside, delphinidin-3-sambubioside, and total anthocyanins, respectively. The dose-normalized C(max) estimates were 0.036, 0.015, and 0.023 ng/mL/mg in the same sequence. They were reached each at 1.5 hours (median) after intake. The geometric means of t1/2 were 2.18, 3.34, and 2.63 hours for cyanidin-3-sambubioside, delphinidin-3-sambubioside, and total anthocyanins, respectively. The urinary excretion of intact anthocyanins was fast and appeared to be monoexponential. To evaluate the contribution of anthocyanins to the health-protecting effects of Hibiscus sabdariffa L. extract, it will be necessary to perform further studies on both the intact glycosides and their in vivo metabolites or conjugates in human plasma and urine.     

Inhibition of erythrocyte “apoptosis” by catecholamines

Osmotic shock, oxidative stress and Cl⁻ removal activate a non-selective Ca²⁺-permeable cation conductance in human erythrocytes. The entry of Ca²⁺ leads to activation of a scramblase with subsequent exposure of phosphatidylserine at the cell surface. Phosphatidylserine mediates binding to phosphatidylserine receptors on macrophages which engulf and degrade phosphatidylserine exposing cells. Moreover, phosphatidylserine exposure may lead to adherence of erythrocytes to the vascular wall. In the present study, we explored whether activation of the non-selective cation conductance and subsequent phosphatidylserine exposure might be influenced by catecholamines. Phosphatidylserine exposure has been determined by FITC-annexin V binding while cell volume was estimated from forward scatter in FACS analysis. Removal of Cl⁻ enhanced annexin binding and decreased forward scatter, an effect significantly blunted by the β agonist isoproterenol (IC₅₀ approx. 1 μM). Fluo-3 fluorescence measurements revealed an increase of cytosolic Ca²⁺ activity following Cl⁻ removal, an effect again significantly blunted by isoproterenol exposure (10 μM). Whole-cell patch-clamp experiments performed in Cl⁻ free bath solution indeed disclosed a time-dependent inactivation of a non-selective cation conductance following isoproterenol exposure (10 μM). Phenylephrine (IC₅₀<10 μM), dobutamine (IC₅₀ approx. 1 μM) and dopamine (IC₅₀ approx. 3 μM) similarly inhibited the effect of Cl⁻ removal on annexin binding and forward scatter. In conclusion, several catecholamines inhibit the Cl⁻ removal-activated Ca²⁺ entry into erythrocytes, thus preventing increase of cytosolic Ca²⁺ activity, subsequent cell shrinkage and activation of erythrocyte scramblase. The catecholamines thus counteract erythrocyte phosphatidylserine exposure and subsequent clearance of erythrocytes from circulating blood.