Biofilm retention on surfaces with variable roughness and hydrophobicity.

Biofilms on food processing equipment cause food spoilage and pose a hazard to consumers. The bacterial community on steel surfaces in a butcher's shop was characterized, and bacteria representative of this community enriched from minced pork were used to study biofilm retention. Stainless steel (SS) was compared to two novel nanostructured sol-gel coatings with differing hydrophobicity. Surfaces were characterized with respect to roughness, hydrophobicity, protein adsorption, biofilm retention, and community composition of the retained bacteria. Fewer bacteria were retained on the sol-gel coated surfaces compared to the rougher SS. However, the two sol-gel coatings did not differ in either protein adsorption, biofilm retention, or microbial community composition. When polished to a roughness similar to sol-gel, the SS was colonized by the same amount of bacteria as the sol-gel, but the bacterial community contained fewer Pseudomonas cells. In conclusion, biofilm retention was affected more by surface roughness than chemical composition under the condition described in this study.

Telomere length among the elderly and oldest-old.

Human chromosomes terminate in a number of repeats of the sequence TTAGGG. At birth, each chromosome end is equipped with approximately 15 kb of telomere sequence, but this sequence is shortened during each cell division. In cell cultures telomere shortening is associated with senescence, a phenomenon that has also been observed in normal adult tissues, indicating that telomere loss is associated with organismal ageing. Previous work has established that the rate of telomere loss in humans is age dependent, and recent work shows a sex-specific difference in telomere length and shortening in individuals over the age span of 20 to 75 years. Here, terminal restriction fragment lengths on DNA purified from whole blood were measured to examine the mean telomere length in a cross-sectional cohort of 816 Danish individuals of age 73 to 101 years. In this age group, females show a linear correlation between telomere length and age, whereas the pattern tends to be nonlinear (quadratic in age) for males. This difference in telomere length dynamics between the 2 sexes may be caused by several different mechanisms, including differences in selection by mortality, differences in leukocyte population or different telomerase expression pattern.

The heritability of telomere length among the elderly and oldest-old.

A tight link exists between telomere length and both population doublings of a cell culture and age of a given organism. The more population doublings of the cell culture or the higher the age of the organism, the shorter the telomeres. The proposed model for telomere shortening, called the end replication problem, explains why the telomere erodes at each cellular turnover. Telomere length is regulated by a number of associated proteins through a number of different signaling pathways. The determinants of telomere length were studied using whole blood samples from 287 twin pairs aged 73 to 95 years. Structural equation models revealed that a model including additive genetic effects and non-shared environment was the best fitting model and that telomere length was moderately heritable, with an estimate that was sensitive to the telomere length standardization procedure. Sex-specific analyses showed lower heritability in males, although not statistically significant, which is in line with our earlier finding of a sex difference in telomere dynamics among the elderly and oldest-old.

The pattern of chromosome-specific variations in telomere length in humans is determined by inherited, telomere-near factors and is maintained throughout life.

In this study the telomere length distribution on individual chromosome arms in humans has been characterized. Using fluorescent in situ hybridisation (FISH) followed by computer-assisted analysis of digital images, we show that the distribution of telomere length on individual chromosome arms is not random, but that humans have a common telomere profile. This profile exists in both lymphocytes, amniocytes and fibroblasts, and is conserved during life until about the age of 100. We find that the length of the telomeres generally follows the length of the chromosomes and that the chromosome specific differences in telomere length are determined by factors located very distally on the chromosome arms. In addition to the common profile, we also find that each individual has specific characteristics. Based on analysis of both monozygotic and dizygotic twins, we find that these characteristics are partly inherited. For each chromosome, age-related chromosome loss correlates negatively with telomere length. This suggests that decrease in telomere length may be an element in age-related genome instability.

Gender and telomere length: systematic review and meta-analysis.

BACKGROUND: It is widely believed that females have longer telomeres than males, although results from studies have been contradictory. METHODS: We carried out a systematic review and meta-analyses to test the hypothesis that in humans, females have longer telomeres than males and that this association becomes stronger with increasing age. Searches were conducted in EMBASE and MEDLINE (by November 2009) and additional datasets were obtained from study investigators. Eligible observational studies measured telomeres for both females and males of any age, had a minimum sample size of 100 and included participants not part of a diseased group. We calculated summary estimates using random-effects meta-analyses. Heterogeneity between studies was investigated using sub-group analysis and meta-regression. RESULTS: Meta-analyses from 36 cohorts (36,230 participants) showed that on average females had longer telomeres than males (standardised difference in telomere length between females and males 0.090, 95% CI 0.015, 0.166; age-adjusted). There was little evidence that these associations varied by age group (p=1.00) or cell type (p=0.29). However, the size of this difference did vary by measurement methods, with only Southern blot but neither real-time PCR nor Flow-FISH showing a significant difference. This difference was not associated with random measurement error. CONCLUSIONS: Telomere length is longer in females than males, although this difference was not universally found in studies that did not use Southern blot methods. Further research on explanations for the methodological differences is required.

Quantification of bacteria on abiotic surfaces by laser scanning cytometry: an automated approach to screen the antifouling properties of new surface coatings.

Bacterial biofilms are a persistent source of contamination, and much effort has been invested in developing antifouling surfaces or coatings. A bottleneck in developing such coatings is often the time-consuming task of screening and evaluating a large number of surface materials. An automated high-throughput assay is therefore needed. In this study, we present a promising technique, laser scanning cytometry (LSC), for automated quantification of bacteria on surfaces. The method was evaluated by quantifying young Staphylococcus xylosus biofilms on glass surfaces using LSC and comparing the results with cell counts obtained by fluorescence microscopy. As an example of application, we quantified bacterial adhesion to seven different sol-gel-based coatings on stainless steel. The surface structure and hydrophobicity of the coatings were analyzed using atomic force microscopy and water contact angle measurements. Among the coatings tested, a significant reduction in adhesion of S. xylosus was observed only for one coating, which also had a unique surface microstructure. LSC was particularly sensitive for quantification at low cell densities, and the adhered bacteria could be quantified both as cell number and as area coverage. The method proved to be an excellent alternative to microscopy for fast and reproducible quantification of microbial colonization on abiotic surfaces.

Entrapment of subtilisin in ceramic sol-gel coating for antifouling applications.

Enzymes with antifouling properties are of great interest in developing nontoxic antifouling coatings. A bottleneck in developing enzyme-based antifouling coatings is to immobilize the enzyme in a suitable coating matrix without compromising its activity and stability. Entrapment of enzymes in ceramics using the sol-gel method is known to have several advantages over other immobilization methods. The sol-gel method can be used to make robust coatings, and the aim of this study was to explore if sol-gel technology can be used to develop robust coatings harboring active enzymes for antifouling applications. We successfully entrapped a protease, subtilisin (Savinase, Novozymes), in a ceramic coating using a sol-gel method. The sol-gel formulation, when coated on a stainless steel surface, adhered strongly and cured at room temperature in less than 8 h. The resultant coating was smoother and less hydrophobic than stainless steel. Changes in the coating's surface structure, thickness and chemistry indicate that the coating undergoes gradual erosion in aqueous medium, which results in release of subtilisin. Subtilisin activity in the coating increased initially, and then gradually decreased. After 9 months, 13% of the initial enzyme activity remained. Compared to stainless steel, the sol-gel-coated surfaces with active subtilisin were able to reduce bacterial attachment of both Gram positive and Gram negative bacteria by 2 orders of magnitude. Together, our results demonstrate that the sol-gel method is a promising coating technology for entrapping active enzymes, presenting an interesting avenue for enzyme-based antifouling solutions.

No association between telomere length and survival among the elderly and oldest old.

BACKGROUND: The consistent findings of a negative correlation between telomere length and replicative potential of cultured cells, as well as a decreasing telomere length in a number of different tissues in humans with age, have led to the suggestion that telomeres play a role in cellular aging in vivo and ultimately even in organismal aging. Furthermore, one small longitudinal study of elderly individuals has suggested that longer telomeres are associated with better survival. METHODS: Telomere length was measured as mean terminal restriction fragment length on blood cells from 812 persons, age 73 to 101 years, who participated in population-based surveys in 1997-1998. Among the participants were 652 twins. The participants were followed up through the Danish Civil Registration system until January 2005, at which time 412 (51%) were dead. RESULTS: Univariate Cox regression analyses revealed that longer telomeres were associated with better survival (hazard ratios = 0.89 [95% confidence interval = 0.76-1.04] per 1 kb in males and 0.79 [0.72-0.88] per 1 kb in females, respectively). However, including age in the analyses changed the estimates to 0.97 (0.83-1.14) and 0.93 (0.85-1.03), respectively. Intrapair comparison showed that among 175 twin pairs in which at least one died during follow up, it was the twin with the shorter telomere length who died first in 97 (55%) of the pairs (95% confidence interval = 48-63%). We could not confirm the recently reported negative correlation between telomere length and obesity or between telomere length and smoking. CONCLUSION: This longitudinal study of the elderly and oldest old does not support the hypothesis that telomere length is a predictor for remaining lifespan once age is controlled for.

Variations in IBD (ACAD8) in children with elevated C4-carnitine detected by tandem mass spectrometry newborn screening.

The isobutyryl-CoA dehydrogenase (IBD) enzyme is involved in the degradation of valine. IBD deficiency was first reported in 1998 and subsequent genetic investigations identified acyl-CoA dehydrogenase (ACAD) 8, now IBD, as the gene responsible for IBD deficiency. Only three individuals homozygous or compound heterozygous for variations in the IBD gene have been reported. We present IBD deficiency in an additional four newborns with elevated C(4)-carnitine identified by tandem mass spectrometry (MS/MS) screening in Denmark and the United States. Three showed urinary excretions of isobutyryl-glycine, and in vitro probe analysis of fibroblasts from two newborns indicated enzymatic IBD defect. Molecular genetic analysis revealed seven new rare variations in the IBD gene (c.348C>A, c.400G>T, c.409G>A, c.455T>C, c.958G>A, c.1000C>T and c.1154G>A). Furthermore, sequence analysis of the short-chain acyl-CoA dehydrogenase (SCAD) gene revealed heterozygosity for the prevalent c.625G>A susceptibility variation in all newborns and in the first reported IBD patient. Functional studies in isolated mitochondria demonstrated that the IBD variations present in the Danish newborn (c.409G>A and c.958G>A) together with a previously published IBD variation (c.905G>A) disturbed protein folding and reduced the levels of correctly folded IBD tetramers. Accordingly, low/no IBD residual enzyme activity was detectable when the variant IBD proteins were overexpressed in Chang cells.

[Qualitative analysis of subjective concepts of illness]. / Qualitative Analyse subjektiver Krankheitskonzepte - Erstellung und Validierung eines Kategoriensystems für den Fragebogen zum Krankheitskonzept (Bischoff, Husen, Schaefer und Reichel) -

Patients' subjective concepts of illness play an important role in the progress and outcome of psychotherapeutic treatment. Therefore, their reliable and valid assessment is of high practical value. The subject of this article is the development and validation of a system of categories for the qualitative evaluation of open answers in a newly developed questionnaire for concepts of illness by Bischoff, Husen, Reichel and Schaefer (in preparation). The new instrument consists of an open and a closed part for assessing subjective concepts of illness. In order to evaluate the open answers a system of classification was constructed following to the principles of qualitative content analysis. Therefore, the answers were summarized into subcategories according to their topics. The subcategories again were assigned to major categories. Major categories emerged to be "unfavourable life circumstances", "interpersonal problems", "intrapersonal problems", "somatic/physical problems" as well as a residual category for unscorable answers. Besides examining the adequacy of the constructed categories and their reliability several hypotheses of validity were derived and empirically tested. It was possible to develop a categorical system for daily practical use which is able to assess contents of subjective concepts of illness.

[Evaluation of the "Psychosomatic Group Therapy" (PSG)]. / Evaluation der Bad Dürkheimer Psychosomatikgruppe.

The changes in the public health system in Germany have led to an increasing number of in-house patients in clinics for psychotherapy, whose attitudes towards their disorders can be described as medically orientated and who are less motivated towards psychotherapy. To integrate these patients with low motivation or little experience and knowledge of behavior therapy, therapists of the Fachklinik Bad Dürkheim developed a special program for group therapy ("Psychosomatic Group Therapy", PSG). The goals of this program, which consists of 10 sessions, are: 1. Teaching the basics of psychosomatic medicine and behavioral therapy, 2. imparting a bio-psycho-social model of psychosomatic disorders, and 3. initiating and supporting basic capabilities of self management, thereby increasing the motivation for behavior therapy and reducing the symptoms of the patients. This empirical study follows a one-group pre-post design. The results show several positive outcomes of the program: In the eyes of the patients, the sessions themselves and the exercises between the sessions ("homework") are didactically excellent and personally relevant. The patients' knowledge about and their attitudes towards psychosomatics change in a positive direction. Furthermore, the motivation for psychotherapy increases and general improvements in physical and psychological symptoms can be shown. However, these changes in motivation do not correlate with changes in knowledge of and attitudes towards psychotherapy. The reasons for these results are critically discussed.