Different Types of Door-Opening Motions as Contributing Factors to Containment Failures in Hospital Isolation Rooms

Hospital isolation rooms are vital for the containment (when under negative pressure) of patients with, or the protection (when under positive pressure) of patients, from airborne infectious agents. Such facilities were essential for the management of highly contagious patients during the 2003 severe acute respiratory syndrome (SARS) outbreaks and the more recent 2009 A/H1N1 influenza pandemic. Many different types of door designs are used in the construction of such isolation rooms, which may be related to the space available and affordability. Using colored food dye as a tracer, the qualitative effects of door-opening motions on the dissemination of potentially contaminated air into and out of a single isolation room were visualized and filmed using Reynolds-number-equivalent, small-scale, water-tank models fitted with programmable door-opening and moving human figure motions. Careful scaling considerations involved in the design and construction of these water-tank models enabled these results to be accurately extrapolated to the full-scale situation. Four simple types of door design were tested: variable speed single and double, sliding and hinged doors, in combination with the moving human figure. The resulting video footage was edited, synchronized and presented in a series of split-screen formats. From these experiments, it is clear that double-hinged doors pose the greatest risk of leakage into or out of the room, followed by (in order of decreasing risk) single-hinged, double-sliding and single-sliding doors. The relative effect of the moving human figure on spreading any potential contamination was greatest with the sliding doors, as the bulk airflows induced were large relative to those resulting from these door-opening motions. However, with the hinged doors, the airflows induced by these door-opening motions were significantly greater. Further experiments involving a simulated ventilated environment are required, but from these findings alone, it appears that sliding-doors are far more effective for hospital isolation room containment.     

Uptake of [18F] EF5 as a Tracer for Hypoxic and Aggressive Phenotype in Experimental Head and Neck Squamous Cell Carcinoma

PURPOSE: This study aims to investigate whether the uptake of 2-(2-nitro-1H-imidazol-1-yl)-N-(2,2,3,3,3-pentafluoropropyl)-acetamide ([¹⁸F]EF5) and 2-deoxy-2-[¹⁸F]fluoro-d-glucose ([¹⁸F]FDG) is associated with a hypoxia-driven adverse phenotype in head and neck squamous cell carcinoma cell lines and tumor xenografts. METHODS: Xenografts were imaged in vivo, and tumor sections were stained for hypoxia-inducible factor 1α (Hif-1α), carbonic anhydrase IX (CA IX), and glucose transporter 1 (Glut-1). Tracer uptakes and the expression of Hif-1α were determined in cell lines under 1% hypoxia. RESULTS: High [¹⁸F]EF5 uptake was seen in xenografts expressing high levels of CA IX, Glut-1, and Hif-1α, whereas low [¹⁸F]EF5 uptake was detected in xenografts expressing low amounts of CA IX and Hif-1α. The uptake of [¹⁸F]EF5 between cell lines varied extensively under normoxic conditions. A clear correlation was found between the expression of Hif-1α and the uptake of [¹⁸F]FDG during hypoxia. CONCLUSIONS: The UT-SCC cell lines studied differed with respect to their hypoxic phenotypes, and these variations were detectable with [¹⁸F]EF5. Acute hypoxia increases [¹⁸F]FDG uptake in vitro, whereas a high [¹⁸F]EF5 uptake reflects a more complex phenotype associated with hypoxia and an aggressive growth pattern.     

Prolyl hydroxylase PHD3 enhances the hypoxic survival and G1 to S transition of carcinoma cells

Hypoxia restricts cell proliferation and cell cycle progression at the G1/S interface but at least a subpopulation of carcinoma cells can escape the restriction. In carcinoma hypoxia may in fact select for cells with enhanced hypoxic survival and increased aggressiveness. The cellular oxygen sensors HIF proline hydroxylases (PHDs) adapt the cellular functions to lowered environmental oxygen tension. PHD3 isoform has shown the strongest hypoxic upregulation among the family members. We detected a strong PHD3 mRNA expression in tumors of head and neck squamous cell carcinoma (HNSCC). The PHD3 expression associated with expression of hypoxic marker gene. Using siRNA in cell lines derived from HNSCC we show that specific inhibition of PHD3 expression in carcinoma cells caused reduced cell survival in hypoxia. The loss of PHD3, but not that of PHD2, led to marked cell number reduction. Although caspase-3 was activated at early hypoxia no induction of apoptosis was detected. However, hypoxic PHD3 inhibition caused a block in cell cycle progression. Cell population in G1 phase was increased and the population in S phase reduced demonstrating a block in G1 to S transition under PHD3 inhibition. In line with this, the level of hyperphosphorylated retinoblastoma protein Rb was reduced by PHD3 knock-down in hypoxia. PHD3 loss led to increase in cyclin-dependent kinase inhibitor p27 expression but not that of p21 or p16. The data demonstrated that increased PHD3 expression under hypoxia enhances cell cycle progression and survival of carcinoma cells.     

Active feeding of downstream migrating juvenile pink salmon (Oncorhynchus gorbuscha) revealed in a large Barents Sea river using diet and stable isotope analysis

The recent, rapid spreading of non-native pink salmon Oncorhynchus gorbuscha in the North Atlantic area has raised concerns about their possible negative impacts on native salmonid species. Potential interactions include competition for food resources during the short freshwater phase of juvenile O. gorbuscha, but little is known about their feeding behavior in the newly occupied North Atlantic rivers. Using stable isotope and stomach content analyses, patterns of freshwater feeding of non-native O. gorbuscha fry were studied in a large Fennoscandian river, the Teno, that discharges to the Barents Sea. Changes in stable isotope values (δ¹³C, δ¹⁵N, δ³⁴S) and stomach contents from the period of emergence (April to mid-May) to estuarine entry (late May/June) were examined and provided both temporally integrated and short-term indicators of freshwater feeding dependency. In addition, the occurrence of juvenile O. gorbuscha and changes in their length and weight during their emergence/migration period were investigated. Juvenile O. gorbuscha were at the spawning grounds from April through to mid-May with abundance peaking in mid-May. Fish moved to the estuary by late May and their abundance decreased toward June, and their body size increased concurrently. Stomach analyses indicated no feeding activity in April–early May in the spawning areas, but the stomach fullness indices increased markedly in fish sampled in the estuary in May and June. The most important prey items in stomachs were Chironomidae and Ephemeroptera larvae. Significant changes in all analysed stable isotopes were detected among sample periods, with a peak in mid-May and June showing significantly lower values than other sample periods. A change from the higher values reflective of parental marine feeding to the lower values reflective of freshwater feeding indicated active in-river feeding by juveniles during the study period. The documented active freshwater feeding of non-native juvenile O. gorbuscha suggests potential resource competition with native fluvial fishes, particularly salmonids.     

Species' identification and microarray-based comparative genome analysis of Streptomyces species isolated from potato scab lesions in Norway

Streptomyces strains were isolated from scab lesions on potatoes collected from different parts of Norway. Twenty-eight plant-pathogenic strains, as tested on seedlings of radish and on potato, were identified on the basis of physiological and molecular criteria. Polymerase chain reaction (PCR) analysis, using species-specific primers, and sequencing of the 16S rRNA gene identified 14 nonmelanin-producing strains to S. turgidiscabies. Fourteen melanin-producing strains were detected with primers specific to S. scabies, but whole-genome microarray analysis, based on 12 766 probes designed for 8848 predicted open reading frames (ORFs) of S. scabies, showed that the 14 strains were different from S. scabies. They were subsequently identified to be S. europaeiscabiei based on the internal transcribed spacer (ITS) sequences of the rRNA genes. This is the first report of the occurrence of S. turgidiscabies and S. europaeiscabiei in Norway. The putative 762 genes exhibiting the highest sequence differences between strains of S. europaeiscabiei and S. scabies according to microarray analysis were concentrated in relatively few gene ontology (GO) categories, including 'symbiosis and mutualism through parasitism', 'cell death' and 'responses to biotic stimulus', whereas genes related to primary metabolism appeared to be more conserved. Microarray data and 16S rRNA gene phylogeny showed, consistently, that there were two genetically distinguishable groups of S. europaeiscabiei on the basis of differences in 131 genes. The results provide novel information about the genetic variability of S. europaeiscabiei and the gene-specific variability between the genomes of S. europaeiscabiei and S. scabies. The usefulness of a custom-designed, whole-genome oligonucleotide microarray in a survey of bacterial plant pathogens was demonstrated.     

The importance of timing and number of surveys in fungal biodiversity research

Practical conservation of biological diversity is dependent on reliable knowledge about what kind, how much, and where the diversity is. To obtain such knowledge three questions, why, what, and how, must be answered before commencing any biodiversity survey. While the questions why and what are often value decisions and thus determined outside the realm of scientific research, the question about how the surveys are conducted lies in the heart of science. Here, we report an intensive repeated survey of wood-inhabiting fungi with the aim of determining the optimal timing and number of the surveys for reliable estimation of the diversity of this species group. The research focusing on the ecology of wood-inhabiting fungi has been increasing but little is known about the reliability of the methods. The variation in the estimates of diversity among surveys was high and the results varied between studied species groups. The site-scale detectability for species belonging to different groups varied from 10 to 95% depending on the survey month and the species group. We conclude that because detectability of many fungi turned out to be poor even when surveys were conducted at an optimal time, the common practice of using a single fruit body survey to estimate fungal diversity of any given area is not enough. We suggest that multiple surveys at an optimal time should be a norm in fungal diversity studies. Improper methodology results in unreliable outcomes that have potential to hamper our goal of conserving the biological diversity.     

Requirement for RNA helicase CsdA for growth of Yersinia pseudotuberculosis IP32953 at low temperatures

The expression of csdA, encoding an RNA helicase, was induced at 3°C in Yersinia pseudotuberculosis. The role of CsdA in Y. pseudotuberculosis under cold conditions was confirmed by impaired growth of insertional csdA mutants at 3°C. The results suggest that CsdA is crucial for Y. pseudotuberculosis survival in the chilled food chain.