Biosecurity measures in 48 isolation facilities managing highly infectious diseases

Biosecurity measures are traditionally applied to laboratories, but they may also be usefully applied in highly specialized clinical settings, such as the isolation facilities for the management of patients with highly infectious diseases (eg, viral hemorrhagic fevers, SARS, smallpox, potentially severe pandemic flu, and MDR- and XDR-tuberculosis). In 2009 the European Network for Highly Infectious Diseases conducted a survey in 48 isolation facilities in 16 European countries to determine biosecurity measures for access control to the facility. Security personnel are present in 39 facilities (81%). In 35 facilities (73%), entrance to the isolation area is restricted; control methods include electronic keys, a PIN system, closed-circuit TV, and guards at the doors. In 25 facilities (52%), identification and registration of all staff entering and exiting the isolation area are required. Access control is used in most surveyed centers, but specific lacks exist in some facilities. Further data are needed to assess other biosecurity aspects, such as the security measures during the transportation of potentially contaminated materials and measures to address the risk of an "insider attack."     

Synthesis of benzamide derivatives and their evaluation as antiprion agents

A new set of 5-(2-(pyrrolidin-1-yl)acetamido)-N-butyl-2-(substituted)benzamide and 5-(2-(piperidin-1-yl)acetamido)-N-butyl-2-(substituted) benzamide derivatives were synthesized in which as structural features the 2-(1-pyrrolidinyl)- or 2-(1-piperidyl)acetylamino group or a diphenylether moiety are associated to a benzamide scaffold. Their binding affinity for human PrP(C) and inhibition of its conversion into PrP(Sc) were determined in vitro; moreover, the antiprion activity was assayed by inhibition of PrP(Sc) accumulation in scrapie-infected mouse neuroblastoma cells (ScN2a) and scrapie mouse brain (SMB) cells. The results clearly indicate the benzamide derivatives as attractive lead compounds for the development of potential therapeutic agents against prion disease.     

TRAIL-related neurotoxicity implies interaction with the Wnt pathway in human neuronal cells in vitro

Tumor necrosis factor related apoptosis inducing ligand (TRAIL) is involved in amyloid beta dependent neurotoxicity via the extrinsic pathway. Recently, several genes modulating TRAIL cytotoxicity have been characterized, providing evidence for a role of wingless-type mouse mammary tumor virus integration site family (Wnt), Jun-N-terminal kinase and other pathways in increased cell susceptibility to the cytokine. We investigated whether neurotoxic effects of TRAIL could be due to modulation of the Wnt signaling pathway. Western blot analysis of Wnt in SH-SY5Y human neuroblastoma cells showed significantly decreased Wnt expression in cultures treated with TRAIL. Correspondingly, both phosphorylation of glycogen synthase kinase 3 beta and degradation of cytoplasmic β-catenin were increased, as well as phosphorylation of the τ protein, bringing about the picture of neuronal damage. As a counterproof of the interaction of TRAIL with the Wnt pathway, the addition of the specific glycogen synthase kinase 3 beta inhibitor SB216763 resulted in rescue of a significant percent of cells from TRAIL-induced apoptosis. The rescue was total when the caspase 8 inhibitor z-IETD-FMK was added in combination with SB216763. Results show that, probably, in addition to triggering caspase signaling, TRAIL also interferes with the Wnt pathway, additionally concurring to neuronal damage. These data suggest that the Wnt pathway substantially contributes to the TRAIL-related neurotoxicity and indicate the TRAIL system as a candidate target for pharmacological treatment of Alzheimer's disease and related disorders.     

Cellular concentrations of DDB2 regulate dynamic binding of DDB1 at UV-induced DNA damage

Nucleotide excision repair (NER) is the principal pathway for counteracting cytotoxic and mutagenic effects of UV irradiation. To provide insight into the in vivo regulation of the DNA damage recognition step of global genome NER (GG-NER), we constructed cell lines expressing fluorescently tagged damaged DNA binding protein 1 (DDB1). DDB1 is a core subunit of a number of cullin 4-RING ubiquitin ligase complexes. UV-activated DDB1-DDB2-CUL4A-ROC1 ubiquitin ligase participates in the initiation of GG-NER and triggers the UV-dependent degradation of its subunit DDB2. We found that DDB1 rapidly accumulates on DNA damage sites. However, its binding to damaged DNA is not static, since DDB1 constantly dissociates from and binds to DNA lesions. DDB2, but not CUL4A, was indispensable for binding of DDB1 to DNA damage sites. The residence time of DDB1 on the damage site is independent of the main damage-recognizing protein of GG-NER, XPC, as well as of UV-induced proteolysis of DDB2. The amount of DDB1 that is temporally immobilized on damaged DNA critically depends on DDB2 levels in the cell. We propose a model in which UV-dependent degradation of DDB2 is important for the release of DDB1 from continuous association to unrepaired DNA and makes DDB1 available for its other DNA damage response functions.     

The impact of mitochondrial DNA on human lifespan: a view from studies on centenarians

The role of inherited and somatic mutations of mitochondrial DNA (mtDNA) in aging and longevity is complex and highly controversial, owing to its peculiar genetics, including the phenomenon of heteroplasmy. Most of the data on mtDNA and longevity have been obtained on humans and particularly on centenarians, i. e., people who escaped or delayed the major age-related pathologies and reached the extreme limit of human lifespan. In this review we summarize the most recent advances in this field that suggest a consistent role in human longevity of both germ-line inherited and somatically acquired mutations. The particular case of the association with longevity of the somatic C150T mutation is extensively discussed, challenging the tenet that mtDNA mutations are basically detrimental. We also stress several limitations of our present knowledge, regarding the difficulty in extrapolating to humans the results obtained in animal models, owing to a variety of biological differences, including the very limited genetic variability of mtDNA in the strains used in laboratory experiments. The use of high-throughput technologies and the extensive analysis, possibly at the single cell level, of different tissues and cell types derived from the same individual will help in disentangling the complexity of mtDNA in aging and longevity.     

Multiple advantageous amino acid variants in the NAT2 gene in human populations

Background

Genetic variation at NAT2 has been long recognized as the cause of differential ability to metabolize a wide variety of drugs of therapeutic use. Here, we explore the pattern of genetic variation in 12 human populations that significantly extend the geographic range and resolution of previous surveys, to test the hypothesis that different dietary regimens and lifestyles may explain inter-population differences in NAT2 variation.

Methodology/Principal Findings

The entire coding region was resequenced in 98 subjects and six polymorphic positions were genotyped in 150 additional subjects. A single previously undescribed variant was found (34T>C; 12Y>H). Several aspects of the data do not fit the expectations of a neutral model, as assessed by coalescent simulations. Tajima''s D is positive in all populations, indicating an excess of intermediate alleles. The level of between-population differentiation is low, and is mainly accounted for by the proportion of fast vs. slow acetylators. However, haplotype frequencies significantly differ across groups of populations with different subsistence.

Conclusions/Significance

Data on the structure of haplotypes and their frequencies are compatible with a model in which slow-causing variants were present in widely dispersed populations before major shifts to pastoralism and/or agriculture. In this model, slow-causing mutations gained a selective advantage in populations shifting from hunting-gathering to pastoralism/agriculture. We suggest the diminished dietary availability of folates resulting from the nutritional shift, as the possible cause of the fitness increase associated to haplotypes carrying mutations that reduce enzymatic activity.     

Temporin A is effective in MRSA-infected wounds through bactericidal activity and acceleration of wound repair in a murine model

We investigated the effect of topical temporin A in the management of methicillin-resistant strain of Staphylococcus aureus (MRSA)-infected experimental surgical wounds in mice. The wound, cut through the panniculus carnosus of BALB/c mice, was inoculated with 5x10(7) colony-forming units of MRSA. Mice were treated with Allevyn, temporin A-soaked Allevyn, Allevyn and daily intraperitoneal teicoplanin (7mg/kg), temporin A-soaked Allevyn and daily intraperitoneal teicoplanin. Main outcome measurements were: quantitative bacterial culture, histological examination with assessment of micro-vessel density and of vascular endothelial growth factor (VEGF) expression in tissue sections, and VEGF plasma levels alike. Treatment with temporin-A associated with teicoplanin injection significantly reduced bacterial load to 0.85 x 10(1)+/-0.1 x 10(1)CFU/ml. Histological examination showed that infected mice receiving temporin A-soaked Allevyn (with or without teicoplanin) had a higher degree of granulation tissue formation and collagen deposition compared to the other treated groups. A significant increase in serum VEGF expression was observed in mice receiving temporin A topically and temporin A topically associated with intraperitoneal teicoplanin. In conclusion our results demonstrated that temporin A is effective in the management of infected wounds, by a significant bacterial growth inhibition and acceleration of wound repair process.     

Immunolocalization of histamine H3 receptors on endocrine cells in the rat gastrointestinal tract

The histamine H3 receptor (H3R) has been identified in the gastrointestinal tract of the rat by immunohistochemistry, using the first validated anti-H3 receptor antibody. Immunoreactivity to H3R was exclusively localized to the endocrine cells scattered in the gastrointestinal mucosa, with positive cells being prominently abundant in the gastric fundus, while they were rarely found in the other regions. In the fundus, positive cells were distributed in the lower half of the mucosa and their number significantly decreased after a 24 h-fasting period. Double-labeling studies were undertaken to identify the H3R-immunoreactive cell types in the fundic and antral mucosa. The H3R-immunoreactive cells were positive for chromogranin A. In the fundus, approximately 90% of cells positive to H3R were also positive to the histamine-forming enzyme, histidine decarboxylase. None of the cells expressing H3R displayed immunoreactivity for gastrin, somatostatin or ghrelin. Location, the influence of food deprivation and colocalization with histidine decarboxylase indicate that H3R positive cells correspond to the enterochromaffin-like cells (ECL).