Influence of surface roughness on silicone rubber voice prostheses on in vitro biofilm formation and clinical lifetime in laryngectomised patients.

OBJECTIVES: Evaluation of the influence of a smooth surface moulding technique of silicone rubber indwelling voice prostheses on in vitro biofilm formation and analysis of the clinical in situ lifetime. DESIGN: Biofilm formation on smooth and Groningen ultra low resistance (URL) prostheses was studied in an artificial throat model. The clinical lifetime of smooth voice prostheses was compared to the previous lifetime of URL by counting the number of replacements in a consecutive 6-month period in the same patient. PARTICIPANTS: Eleven laryngectomised patients in follow-up who required frequent replacement of their voice prostheses. SETTINGS: Tertiary University Medical Center. RESULTS: Use of a smoother mould and less viscous silicone rubber yielded a decrease in surface roughness from 46 to 8 nm and was accompanied by a 40% reduction in the prevalence of bacteria and yeast in in vitro formed biofilms. Clinically, the lifetime was significantly (P<.005) increased by a factor of 2.1. CONCLUSIONS: This combined in vitro and clinical study suggests that the choice of material and in particular its surface finishing may be determining factors with respect to the clinical lifetime of silicone rubber implants and devices failing due to biofilm formation.

Spore-killing meiotic drive factors in a natural population of the fungus Podospora anserina.

In fungi, meiotic drive is observed as spore killing. In the secondarily homothallic ascomycete Podospora anserina it is characterized by the abortion of two of the four spores in the ascus. We have identified seven different types of meiotic drive elements (Spore killers). Among 99 isolates from nature, six of these meiotic drive elements occurred in a local population. Spore killers comprise 23% of the natural population of P. anserina in Wageningen, The Netherlands, sampled from 1991 to 1997. One Spore-killer type was also found in a French strain dating from 1937. All other isolates found so far are sensitive to spore killing. All seven Spore killer types differ in the percentage of asci that show killing and in their mutual interactions. Interactions among Spore killer types showed either mutual resistance or dominant epistasis. Most killer elements could be assigned to linkage group III but are not tightly linked to the centromere.

Peroxisome proliferator-activated receptor gamma C161-->T polymorphism and coronary artery disease.

BACKGROUND: Peroxisome proliferator-activated receptor gamma (PPAR gamma) as a transcription factor plays an important role in lipid metabolism, glucose homeostasis, insulin sensitivity, obesity, diabetes, foam cell formation and atherogenesis. METHODS AND RESULTS: We have studied distribution of the PPAR gamma C161-->T substitution at exon 6 in 647 Australian Caucasian patients aged < or = 65 years (484 men and 163 women) recruited consecutively, with or without angiographically documented coronary artery disease (CAD). The frequencies of the CC, CT and TT genotypes were 69.8%, 27.7% and 2.5% and the 'T' allele frequency 0.163. They were in Hardy-Weinberg equilibrium and not different between men and women. The BMI and waist to hip ratio (WHR) among patients with CC, CT + TT genotypes were not different (P = 0.878, P = 0.677). However there was a significant association between the polymorphism and CAD. The 'T' allele carriers (CT + TT) had significantly reduced CAD risk compared to the CC homozygotes (odds ratio: 0.457, 95% CI: 0.273-0.763, P = 0.0045) in a logistic regression model after controlling other known risk factors. This reduced risk was particularly evident among CT heterozygotes (odds ratio: 0.466, 95% CI: 0.291-0.746, P = 0.0015), who also had lower apo B and total cholesterol to HDL-C ratios (P < 0.05). CONCLUSION: We report that the PPAR gamma C161-->T substitution is associated with a reduced CAD risk, particularly among CT heterozygous patients, but not with obesity in Australian Caucasian patients. It implicates that the PPAR gamma may have a significant role in atherogenesis, independent of obesity and of lipid abnormalities, possibly via a direct local vascular wall effect.