Enhanced anticaries efficacy of a 0.243% sodium fluoride/10% xylitol/silica dentifrice: 3-year clinical results

PURPOSE: To evaluate the efficacy of a sodium fluoride (NaF)/silica/xylitol dentifrice compared with that of a positive control NaF/silica dentifrice on caries increments in school children over a 3-year period in an area without an optimal level of fluoride in the drinking water (mean level <0.1 ppm). MATERIALS AND METHODS: A 3-year, double-blind clinical caries study was conducted in 2,630 children initially aged 8-10 years at 17 schools in the San Jose, Costa Rica metropolitan area. Clinical dental examinations were performed at participating schools utilizing portable dental equipment. Caries evaluations employed conventional tactile/visual methodology consisting of artificial light, dental mirrors and single-edge #23 explorers. Children accepted into the study were stratified by age and sex into two balanced groups within each school, and randomly assigned to use either a positive control dentifrice containing 0.243% NaF/silica or a test dentifrice containing 0.234% NaF/silica/10% xylitol. Children were instructed to brush with the assigned dentifrice twice daily. Caries evaluations were conducted at baseline, 2 years, and 3 years. RESULTS: After 3 years, subjects using the 0.234% NaF/silica/10% xylitol dentifrice had statistically significantly reduced decayed/filled surfaces (DFS; -12.3% reduction; P < or = 0.001) and decayed/filled buccal and lingual surfaces (DFS-BL; -10.5% reduction; P < or = 0/01).     

Heterogeneity of cognitive profiles in dementias of the Alzheimer type: theoretical aspects and clinical consequences

Presently, Alzheimer's disease can only be diagnosed with the coexistence of clinical symptoms and the presence of neuropathological alterations. Thus, in the absence of pre mortem biological markers, cognitive deficits form the starting point and the basis of inclusion criteria on which the clinician relies in order to make a putative diagnose of dementia of the Alzheimer type (DTA). Cognitive deficits should thus be accurately described through neuropsychological testing since it is essential to identify the cognitive deterioration patterns of the patients--in terms of selective impairment of cognitive functions--as well as the evolution of these patterns. Regarding this issue, the classical teaching of the Geneva school has proposed a homogeneous deterioration of the aphasic-apraxicagnosic syndrome into four stages. However, recent work does not support this hypothesis. On the contrary, these studies tend to show the presence of heterogeneity in neuropsychological manifestations of the disease. The aim of the present paper is to provide a critical review of this topic through a brief survey of the classical work and research that have recently been conducted. An analysis of the possible candidates responsible for the existence of this heterogeneity of cognitive profiles is presented. Finally, theoretical implications and clinical repercussions are discussed.     

The pain drawing and Waddell's nonorganic physical signs in chronic low-back pain

Pain drawings were obtained from a group of 651 patients who had chronic low-back pain. Pain drawings were rated in four grades according to the degree of organic and nonorganic pain. Experienced and inexperienced evaluators were used. The reliability was excellent with an interevaluator reliability between 73% and 78%. A correlation between pain drawings and Waddell's nonorganic physical signs demonstrated that a large proportion of patients with high Waddell scores had nonorganic pain drawings. No significant differences were noted in the distribution of Waddell scores and pain drawings based on patient gender or payment status (i.e., medicolegal or workers' compensation). Pain drawings afford an important adjunct in the physician's assessment of chronic low-back pain.     

Mutagenesis of a buried polar interaction in an SH3 domain: sequence conservation provides the best prediction of stability effects

The SH3 domain from the Fyn tyrosine kinase possesses a buried hydrogen bond between the side chains of a glutamate (Glu24) and a serine (Ser41) residue. Multiple amino acid substitutions were made at these positions to determine the role of this interaction in the stability and conformational specificity of the domain and to assess the relationship between the thermodynamic stability of mutants and sequence conservation seen in the SH3 domain family. Analysis of single and double alanine mutations indicated that the Glu24-Ser41 interaction contributes 0.50 kcal/mol to the stability of the domain. However, disruption of the Glu24-Ser41 interaction did not impair peptide binding function, suggesting that the interaction is not critical for conformational specificity. The stability of the domain was not increased by the replacement of these residues with different combinations of hydrophobic residues or with potential salt bridge forming residues. Despite their similar structural roles in the Fyn SH3 domain, the Ser41 position was considerably more tolerant to substitution than was the Glu24 position. An alignment of >350 different SH3 domains has been completed in our laboratory. A statistically significant correlation was found between the conservation data for the Glu24 and Ser41 positions and the thermodynamic stabilities of the mutants constructed at these positions. Surprisingly, our analysis of sequence alignment data provided a more accurate prediction of the stability of mutants than did examination of the three-dimensional structure of the domain.     

Variants of the 3' region of the cagA gene in Helicobacter pylori isolates from patients with different H. pylori-associated diseases

The CagA protein of Helicobacter pylori is an immunogenic antigen of variable size and unknown function that has been associated with increased virulence as well as two mutually exclusive diseases, duodenal ulcer and gastric carcinoma. The 3' region of the cagA gene contains repeated sequences. To determine whether there are structural changes in the 3' region of cagA that predict outcome of H. pylori infection, we examined 155 cagA gene-positive H. pylori isolates from Japanese patients including 50 patients with simple gastritis, 40 with gastric ulcer, 35 with duodenal ulcer, and 30 with gastric cancer. The 3' region of the cagA gene was amplified by PCR followed by sequencing. CagA proteins were detected by immunoblotting using a polyclonal antibody against recombinant CagA. One hundred forty-five strains yielded PCR products of 642 to 651 bp; 10 strains had products of 756 to 813 bp. The sequence of the 3' region of the cagA gene in Japan differs markedly from the primary sequence of cagA genes from Western isolates. Sequence analysis of the PCR products showed four types of primary gene structure (designated types A, B, C, and D) depending on the type and number of repeats. Six of the seven type C strains were found in patients with gastric cancer (P < 0.01 in comparison to noncancer patients). Comparison of type A and type C strains from patients with gastric cancer showed that type C was associated with higher levels of CagA antibody and more severe degrees of atrophy. Differences in cagA genotype may be useful for molecular epidemiology and may provide a marker for differences in virulence among cagA-positive H. pylori strains.     

Culture amplification in human colon adenocarcinoma cell line (CaCo-2) combined with an ELISA as a supplementary assay for accurate diagnosis of rotavirus

Culture amplification in colon adenocarcinoma cell line (CaCo-2) combined with enzyme immunoassay (Pathfinder ELISA) was developed as a supplementary tool for rotavirus diagnosis. One hundred and thirty stools in which results by polyacrylamide gel electrophoresis (PAGE) were in agreement with those obtained by ELISA were amplified in the CaCo-2 cell line. After the first passage 100% specimens were revealed as positive by ELISA. This result was confirmed by PAGE and direct electron microscopy (EM) which increased the rates of rotavirus detection up to 100% after the third and fifth cell passages, respectively. All of the amplified negative stools were confirmed as negative. Among discordant results, three of the eight specimens positive by ELISA but negative by PAGE were confirmed as true positive after the third cell passage. False positive ELISA results could be discarded when the samples were culture amplified and retested by the same ELISA. Using the CaCo-2 amplification-ELISA as supplementary assay, sensitivity and specificity were 1.000 and 0.953 for ELISA and 0.917 and 1.000 for PAGE, respectively. The combined CaCo-2 cell line amplification-immunoassay method proved to be suitable both to evaluate increase in sensitivity of newly developed rotavirus assays and for rotaviral amplification before antigen assays.