Antimicrobial activity and biologic potential of silver-substituted calcium phosphate constructs produced with self-propagating high-temperature synthesis.

There is significant demand for synthetic bone substitute materials that can decrease the incidence of implant-based bacterial infections. The intent of this research was to evaluate the antimicrobial activity and biologic potential of calcium phosphate (CaP) constructs substituted with silver (Ag) that were produced via self-propagating high-temperature synthesis (SHS). SHS is a combustion synthesis technique that has successfully generated porous CaP bioceramics intended for use in bone repair. SHS reactions are highly versatile; dopants can be added to the reactant powders to alter product chemistry and morphology. In this research, Ag powder was added to the reactants generating porous CaP constructs containing 0.5, 1, or 2 wt% Ag. Antibacterial performance of the constructs was assessed against Escherichia coli, a representative model for Gram-negative bacteria. Liquid solutions (1 µg/mL) of CaP-Ag particles to phosphate buffered saline were incubated with 10(5) cells/mL. After 24 h, 10 µL of solution were spread on an LB agar plate and cultured for 24 h at 37 °C. Samples cultured with CaP-Ag showed complete bacterial inhibition while the controls (E. coli only and CaP without Ag) exhibited significant colony formation. The effects of Ag concentration on cytotoxicity and biocompatibility were tested in vitro. At 7 days, osteoblasts uniformly enveloped the CaP-Ag particles and displayed a healthy flattened morphology suggesting the concentrations of Ag incorporated into constructs were not cytotoxic. CaP-Ag constructs produced via SHS represent a source of synthetic bone substitute materials that could potentially inhibit, or reduce the incidence of post-operative bacterial infections.

Methodology to study polymers interaction by surface plasmon resonance imaging.

The surface plasmon resonance (SPR) technique has been primarily used in the field of biology, in particular for the study of antibody-antigen interactions. Recently, polymers were introduced to form inclusion complexes. We describe here, a methodology based on surface plasmon resonance imaging to study water-resistant and reversible inclusion complexes using systems which are compatible with a cosmetic use. The purpose of this study is to follow in real time the interaction between two polymers. To carry out this study: •A biochip based on a covalent binding of one "host polymer" on a gold-activated surface was developed.•The binding of the host polymer to a guest polymer was monitored.•The presence of interactions between the ß-cyclodextrins groups of the host polymer and the adamantyl functional groups of the guest polymer and the possibility of dissociating the complex were established. This technique allowed carrying out parallel assays for optimizing the amount of complexes formed, the host polymer being spotted at five concentrations. It was then possible to study the influence of the concentration in host system for two concentrations of the guest polymer. The concentration in the host polymer yielding the highest immobilization of the guest system was further determined.

Biologic Potential of Calcium Phosphate Biopowders Produced via Decomposition Combustion Synthesis.

The aim of this research was to evaluate the biologic potential of calcium phosphate (CaP) biopowders produced with a novel reaction synthesis system. Decomposition combustion synthesis (DCS) is a modified combustion synthesis method capable of producing CaP powders for use in bone tissue engineering applications. During DCS, the stoichiometric ratio of reactant salt to fuel was adjusted to alter product chemistry and morphology. In vitro testing methods were utilized to determine the effects of controlling product composition on cytotoxicity, proliferation, biocompatibility and biomineralization. In vitro, human fetal osteoblasts (ATCC, CRL-11372) cultured with CaP powder displayed a flattened morphology, and uniformly encompassed the CaP particulates. Matrix vesicles containing calcium and phosphorous budded from the osteoblast cells. CaP powders produced via DCS are a source of biologically active, synthetic, bone graft substitute materials.

Developing genomic resources for the common bottlenose dolphin (Tursiops truncatus): isolation and characterization of 153 single nucleotide polymorphisms and 53 genotyping assays.

Although single nucleotide polymorphisms (SNPs) are commonly used in human genetics, they have only recently been incorporated into genetic studies of non-model organisms, including cetaceans. SNPs have several advantages over other molecular markers for studies of population genetics: they are quicker and more straightforward to score, cross-laboratory comparisons of data are less complicated, and they can be used successfully with low-quality DNA. We screened portions of the genome of one of the most abundant cetaceans in U.S. waters, the common bottlenose dolphin (Tursiops truncatus), and identified 153 SNPs resulting in an overall average of one SNP every 463 base pairs. Custom TaqMan(®) Assays were designed for 53 of these SNPs, and their performance was tested by genotyping a set of bottlenose dolphin samples, including some with low-quality DNA. We found that in 19% of the loci examined, the minor allele frequency (MAF) estimated during initial SNP ascertainment using a DNA pool of 10 individuals differed significantly from the final MAF after genotyping over 100 individuals, suggesting caution when making inferences about MAF values based on small data sets. For two assays, we also characterized the basis for unusual clustering patterns to determine whether their data could still be utilized for further genetic studies. Overall results support the use of these SNPs for accurate analysis of both poor and good-quality DNA. We report the first SNP markers and genotyping assays for use in population and conservation genetic studies of bottlenose dolphins.

Detection and typing of human papillomavirus by e6 nested multiplex PCR.

A nested multiplex PCR (NMPCR) assay that combines degenerate E6/E7 consensus primers and type-specific primers was evaluated for the detection and typing of human papillomavirus (HPV) genotypes 6/11, 16, 18, 31, 33, 35, 39, 42, 43, 44, 45, 51, 52, 56, 58, 59, 66, and 68 using HPV DNA-containing plasmids and cervical scrapes (n = 1,525). The performance of the NMPCR assay relative to that of conventional PCR with MY09-MY11 and GP5+-GP6+ primers, and nested PCR with these two primer sets (MY/GP) was evaluated in 495 cervical scrapes with corresponding histologic and cytologic findings. HPV prevalence rates determined with the NMPCR assay were 34.7% (102 of 294) in the absence of cervical intraepithelial neoplasia (CIN 0), 94.2% (113 of 120) in the presence of mild or moderate dysplasia (CIN I/II), and 97.8% (44 of 45) in the presence of severe dysplasia (CIN III). The combination of all four HPV detection methods applied in the study was taken as "gold standard": in all three morphological subgroups the NMPCR assay had significantly (P < 0.0001) higher sensitivities than the MY09-MY11 and GP5+-GP6+ assays and sensitivities comparable or equal to those of the MY/GP assay. All 18 HPV genotypes investigated were detected among the clinical samples. The ratio of high- to low-risk HPV genotypes increased from 4:1 (80 of 103) in CIN 0 to 19:1 (149 of 157) in CIN I to III. Multiple infections were detected in 47.9% (124 of 259) of the patients. In conclusion, the novel NMPCR method is a sensitive and useful tool for HPV DNA detection, especially when exact HPV genotyping and the identification of multiple HPV infections are required.

A psychological epidemiology of people seeking HIV/AIDS counselling in Kenya: an approach for improving counsellor training.

OBJECTIVE: This study develops a typology of psychological problems reported during HIV/AIDS counselling. This typology provides a framework for training paraprofessional counsellors (PPCs) in East Africa. DESIGN: Study participants included 307 Kenyans tested for HIV at any of six clinics in Nairobi specialising in STDs, tuberculosis and other infectious diseases. Pre-test, post-test, and follow-up counselling was provided by 16 PPCs who are themselves HIV-positive. Data consisted of demographic, physical and psychological information reported by 168 clients who sought follow-up counselling. METHODS: Counselling data were coded using an ipsative method; a unique code was assigned to every distinct topic. Factor analysis with a Varimax rotation reduced the original psychological variables into logical groupings. Multivariate analysis examined the relationship of factors and demographic characteristics. RESULTS: Clients reported 1-10 physical and 1-23 psychological complaints in a single session. Sixty-five percent of female clients reported > or = eight psychological problems; 49% of males reported > or = eight psychological problems. Factor analyses allowed the 109 reported psychological events to be assigned to 15 categories of problems. Multivariate analyses explained little of the variance in the relationship between each client's demographic profile and the psychological factors. CONCLUSIONS: Training for PPCs should be relevant to problems encountered during counselling. Results indicate that PPCs can expect clients to present one or more of the 15 factors during counselling. Demographic characteristics explained small amounts of variance in the distribution of factor scores. The 15 factors produced in this study, although descriptive and preliminary, could form the basis of a training curriculum for HIV PPCs.

[Peptic esophageal stenosis and its relation to reflux esophagitis and esophageal cancer]. / Uber die peptische Osophagusstenose und ihre Beziehung zur Refluxösophagitis und zum Osophaguskarzinom.

Carcinoma of the lower oesophagus can be a complication of a peptic oesophageal stricture caused by reflux oesophagitis. In most cases there is also a hiatal hernia. The main symptoms are dysphagia and epigastric retrosternal pain. The most important examinations are x-ray contrast film of the oesophagus and oesophagogastroscopy combined with biopsy.