Challenges in dental statistics: survey methodology topics

This paper gathers some contributions concerning survey methodology in dental research, as discussed during the first Workshop of the SISMEC STATDENT working group on statistical methods and applications in dentistry, held in Ancona on the 28th September 2011. The first contribution deals with the European Global Oral Health Indicators Development (EGOHID) Project which proposed a comprehensive and standardized system of epidemiological tools (questionnaires and clinical forms) for national data collection on oral health in Europe. The second contribution regards the design and conduct of trials to evaluate the clinical efficacy and safety of toothbrushes and mouthrinses. Finally, a flexible and effective tool used to trace dental age reference charts tailored to Italian children is presented

Determining Real Permittivity from Fresnel Coefficients in GNSS-R

Global Navigation Satellite System Reflectometry (GNSS-R) can be used to derive information about the composition or the properties of ground surfaces, by analyzing signals emitted by GNSS satellites and reflected from the ground. If the received power is measured with linearly polarized antennas, under the condition of smooth surface, the reflected signal is proportional to the modulus of the perpendicular and parallel polarization Fresnel coefficients, which depend on the incidence angle θ, and on the dielectric constant ε of the soil. In general, ε is a complex number; for non-dispersive soils, the imaginary part of ε can be neglected, and a real value of ε is sought. We solve the real valued problem explicitly giving formulas that can be used to determine the dielectric constant ε and we compare the analytical solution with experimental data in the case of sand soil

Extracellular human immunodeficiency virus type-1 Tat protein activates phosphatidylinositol 3-kinase in PC12 neuronal cells

We have here investigated the effect of the regulatory Tat protein of the human immunodeficiency virus type 1 (HIV-1) on the PI 3-kinase catalytic activity in PC12 rat pheochromocytoma cells. After as early as 1 min from the beginning of the treatment with recombinant HIV-1 Tat protein, a significant increase in the tyrosine phosphorylation levels of the p85 regulatory subunit of PI 3-kinase was noticed in 48 h serum-starved PC12 cells. Moreover, the addition of Tat to PC12 cells induced a great increase in PI 3-kinase immunoprecipitated with an anti-phosphotyrosine antibody with a peak of activity (19-fold increase with respect to the basal levels) after a 15-min treatment. This increase in PI 3-kinase activity was significantly higher in PC12 cell cultures supplemented with Tat protein than in cultures stimulated by 100 ng/ml nerve growth factor (NGF; 8-fold increase with respect to the basal levels). Further experiments showed that Tat protein was able to specifically activate PI 3-kinase at picomolar concentrations. In fact: (i) maximal activation of PI 3-kinase was observed at concentrations as low as 1 ng/ml and was specifically blocked by anti-Tat neutralizing antibody; (ii) a Tat-dependent activation was also observed in experiments in which PI 3-kinase activity was evaluated in either anti-Tyr(P) or anti-p85 immunoprecipitates; (iii) 100 nM wortmannin completely blocked the Tat-mediated increase in PI 3-kinase activity both in vitro and in vivo. Our data strongly support the concept that extracellular Tat acts as a cell stimulator, inducing intracellular signal transduction in uninfected cells

Mouse Genome-Wide Association Mapping Needs Linkage Analysis to Avoid False-Positive Loci

We carried out genome-wide association (GWA) studies in inbred mouse strains characterized for their lung tumor susceptibility phenotypes (spontaneous or urethane-induced) with panels of 12,959 (13K) or 138,793 (140K) single-nucleotide polymorphisms (SNPs). Above the statistical thresholds, we detected only SNP rs3681853 on Chromosome 5, two SNPs in the pulmonary adenoma susceptibility 1 (Pas1) locus, and SNP rs4174648 on Chromosome 16 for spontaneous tumor incidence, urethane-induced tumor incidence, and urethane-induced tumor multiplicity, respectively, with the 13K SNP panel, but only the Pas1 locus with the 140K SNP panel. Haplotype analysis carried out in the latter panel detected four additional loci. Loci reported in previous GWA studies failed to replicate. Genome-wide genetic linkage analysis in urethane-treated (BALB/c×C3H/He)F2, (BALB/c×SWR/J)F2, and (A/J×C3H/He)F2 mice showed that Pas1, but none of the other loci detected previously or herein by GWA, had a significant effect. The Lasc1 gene, identified by GWA as a functional element (Nat. Genet., 38:888–95, 2006), showed no genetic effects in the two independent intercross mouse populations containing both alleles, nor was it expressed in mouse normal lung or lung tumors. Our results indicate that GWA studies in mouse inbred strains can suffer a high rate of false-positive results and that such an approach should be used in conjunction with classical linkage mapping in genetic crosses

Evaluation of the galactogogue effect of silymarin on mothers of preterm newborns (<32 weeks)

Hypogalactia has a relative high frequency in women having delivered preterm infants, who often have difficulties in maintaining a sufficient production of milk for their infants’ needs over prolonged periods of time. Recent studies have shown a potential galactogogue effect of silymarin on milk production in animal models (cows and rats) and in humans (mothers of term newborns); nonetheless, none of the studies conducted on humans consisted of double-blind randomized clinical trials and no data are available concerning mothers who delivered preterm infants. The aim of our study was to assess the efficacy of silymarin (BIO-C®) as galactogogue and its tolerability in mothers who delivered preterm infants. We enrolled 50 mothers at 10±1 days post-partum who had delivered infants at ® and placebo arms. No adverse events were observed in the 2 arms among mothers and infants, and silymarin and its metabolites were not detectable in the analyzed human milk samples. Further investigation on specific patient groups affected by hypogalactia, defined according to stricter criteria, should be planned to assess the efficacy of the product in increasing milk production

Nutritional adequacy of a novel human milk fortifier from donkey milk in feeding preterm infants: Study protocol of a randomized controlled clinical trial

Abstract Background Fortification of human milk is a standard practice for feeding very low birth weight infants. However, preterm infants often still experience suboptimal growth and feeding intolerance. New fortification strategies and different commercially available fortifiers have been developed. Commercially available fortifiers are constituted by a blend of ingredients from different sources, including plant oils and bovine milk proteins, thus presenting remarkable differences in the quality of macronutrients with respect to human milk. Based on the consideration that donkey milk has been suggested as a valid alternative for children allergic to cow’s milk proteins, due to its biochemical similarity to human milk, we hypothesized that donkey milk could be a suitable ingredient for developing an innovative human milk fortifier. The aim of the study is to evaluate feeding tolerance, growth and clinical short and long-term outcomes in a population of preterm infants fed with a novel multi-component fortifier and a protein concentrate derived from donkey milk, in comparison to an analogous population fed with traditional fortifier and protein supplement containing bovine milk proteins. Methods The study has been designed as a randomized, controlled, single-blind clinical trial. Infants born <1500 g and <32 weeks of gestational age were randomized to receive for 21 days either a combination of control bovine milk-based multicomponent fortifier and protein supplement, or a combination of a novel multicomponent fortifier and protein supplement derived from donkey milk. The fortification protocol followed is the same for the two groups, and the two diets were designed to be isoproteic and isocaloric. Weight, length and head circumference are measured; feeding tolerance is assessed by a standardized protocol. The occurrence of sepsis, necrotizing enterocolitis and adverse effects are monitored. Discussion This is the first clinical study investigating the use of a human milk fortifier derived from donkey milk for the nutrition of preterm infants. If donkey milk derived products will be shown to improve the feeding tolerance or either of the clinical, metabolic, neurological or auxological outcomes of preterm infants, it would be an absolute innovation in the field of feeding practices for preterm infants. Trial registration ISRCTN - ISRCTN70022881

Dioxin Exposure, from Infancy through Puberty, Produces Endocrine Disruption and Affects Human Semen Quality

BACKGROUND: Environmental toxicants are allegedly involved in decreasing semen quality in recent decades; however, definitive proof is not yet available. In 1976 an accident exposed residents in Seveso, Italy, to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). OBJECTIVE: The purpose of this study was to investigate reproductive hormones and sperm quality in exposed males. METHODS: We studied 135 males exposed to TCDD at three age groups, infancy/prepuberty (1-9 years), puberty (10-17 years), and adulthood (18-26 years), and 184 healthy male comparisons using 1976 serum TCDD levels and semen quality and reproductive hormones from samples collected 22 years later. RESULTS: Relative to comparisons, 71 men (mean age at exposure, 6.2 years; median serum TCDD, 210 ppt) at 22-31 years of age showed reductions in sperm concentration (53.6 vs. 72.5 million/mL; p = 0.025); percent progressive motility (33.2% vs. 40.8%; p < 0.001); total motile sperm count (44.2 vs. 77.5 x 10(6); p = 0.018); estradiol (76.2 vs. 95.9 pmol/L; p = 0.001); and an increase in follicle-stimulating hormone (FSH; 3.58 vs. 2.98 IU/L; p = 0.055). Forty-four men (mean age at exposure, 13.2 years; median serum TCDD, 164 ppt) at 32-39 years of age showed increased total sperm count (272 vs. 191.9 x 10(6); p = 0.042), total motile sperm count (105 vs. 64.9 x10(6); p = 0.036), FSH (4.1 vs. 3.2 UI/L; p = 0.038), and reduced estradiol (74.4 vs. 92.9 pmol/L; p < 0.001). No effects were observed in 20 men, 40-47 years of age, who were exposed to TCDD (median, 123 ppt) as adults (mean age at exposure, 21.5 years). CONCLUSIONS: Exposure to TCDD in infancy reduces sperm concentration and motility, and an opposite effect is seen with exposure during puberty. Exposure in either period leads to permanent reduction of estradiol and increased FSH. These effects are permanent and occur at TCDD concentrations < 68 ppt, which is within one order of magnitude of those in the industrialized world in the 1970s and 1980s and may be responsible at least in part for the reported decrease in sperm quality, especially in younger men