Comparing test methods for moisture-vapor transmission rate (MVTR) for vascular access transparent semipermeable dressings.

BACKGROUND: Catheter insertion sites are commonly covered by transparent film dressings, offering protection of the insertion site from external contaminants and securement of the catheter while allowing site observation through a clear window. Currently, there is considerable focus on creating IV film dressings with ever-increasing moisture vapor transmission rates (MVTR) to prevent the accumulation of moisture under the film and reduce the risk of infection. These increasingly high MVTR IV dressings are often promoted as superior to IV dressings with lesser MVTR values. METHODS: Since there are different methods to determine MVTR, we chose to test a series of commercially available dressings with two standard methods to compare the results and better understand the information provided by this measurement. We used European Standard EN 13726 to test the MVTR of seven different IV dressings with two different methods (upright and inverted). RESULTS: We measured a range of MVTR values from 773 to 2838 g/m2/day for the upright method and from 845 to 30,530 g/m2/day for the inverted method for the seven IV dressings tested. Three dressings showed statistically different MVTR values with the two test methods. CONCLUSIONS: The MVTR test method (upright or inverted) used and considered for IV dressing product selection matters because the results obtained can be very different. We suggest that the upright method is better suited for IV dressings because they are not in constant contact with fluid. We conclude that the inverted method alone is not adequate to compare IV dressings.

Management of incontinence-associated dermatitis patients using a skin protectant in acute care: a case series.

OBJECTIVE: Incontinence-associated dermatitis (IAD) is a common type of irritant contact dermatitis. It is categorised by persistent erythema and can be associated with denudation and/or colonisation and infection. IAD is challenging to treat and affects 3.4-50% of patients. This case series evaluates a novel, elastomeric, advanced skin protectant (3M Cavilon Advanced Skin Protectant) in a UK acute health-care setting, for the management of IAD in patients suffering from moisture-associated skin damage (MASD) in the sacral/genital area. METHOD: The patient's skin was assessed by clinicians using the GLOBIAD classification tool at the point of recruitment and to monitor progress throughout the study period. The product was applied as a single layer in accordance with the instructions for use. Patients, when able, were asked to assess their own pain level using the Wong-Baker FACES pain scale. Photographs were taken as part of the ongoing assessment. RESULTS: The skin protectant was used on average every 2.28 days. Of the 18 IAD patients recruited, 79% (n=11) were classified as IAD-free, based on the GLOBIAD categorisation tool, by the end of the evaluation period. Skin deterioration during the evaluation period was seen in one patient (6%), and of the patients able to complete pain assessments, 55% (n=6) reported a reduction in pain. CONCLUSION: These results suggest that the elastomeric skin protectant, applied every three days, plays a role in the improvement of IAD. The skin protectant adheres to wet and weeping partial-thickness wounds and may aid IAD management. Reducing application to every third day supports a change in practice which may offer benefits to patients and caregivers.

Report of the proceedings of a UK skin safety advisory group.

Moisture-associated skin damage, especially incontinence-associated dermatitis, continues to present significant health challenges and requires multidisciplinary input to provide effective prevention and treatment. In the absence of mandatory reporting such damage is under- or wrongfully reported, resulting in a lack of accurate data on prevalence and costs of associated care. In March this year, a multidisciplinary team of experts met in the UK to seek to determine measures to improve patient skin care. They aimed to identify activities to increase awareness and education, collect data, and improve prevention and treatment regimes. This article describes that discussion and the conclusions made by the group, such as the key actions required to effect policy changes.

The House of Lords debates wound care strategy.

On Tuesday 22 November, the House of Lords (London, UK) held a short debate 'Improving the standard of wound care in the NHS.' It consisted of nine questions from the floor and a response from Lord O'Shaughnessy, The Parliamentary Under-Secretary of State for Health (Conservative). Here, Paul Browning, (Doctoral Research Student, University of Worcester, employed by 3M UK plc) summarises the key points from the evening and explains why it is so important we keep wound care on the Government's agenda.

Direct synthesis of van der Waals solids.

The stacking of two-dimensional layered materials, such as semiconducting transition metal dichalcogenides (TMDs), insulating hexagonal boron nitride (hBN), and semimetallic graphene, has been theorized to produce tunable electronic and optoelectronic properties. Here we demonstrate the direct growth of MoS2, WSe2, and hBN on epitaxial graphene to form large-area van der Waals heterostructures. We reveal that the properties of the underlying graphene dictate properties of the heterostructures, where strain, wrinkling, and defects on the surface of graphene act as nucleation centers for lateral growth of the overlayer. Additionally, we show that the direct synthesis of TMDs on epitaxial graphene exhibits atomically sharp interfaces. Finally, we demonstrate that direct growth of MoS2 on epitaxial graphene can lead to a 10(3) improvement in photoresponse compared to MoS2 alone.

Detection of E. coli O157:H7 in raw ground beef by Pathatrix™ immunomagnetic-separation, real-time PCR and cultural methods.

Detection of Escherichia coli O157:H7 by conventional cultural methods can be difficult in food matrices with a high background flora such as raw ground beef. Raw ground beef samples, artificially contaminated separately with five strains of E. coli O157:H7 at low (~0.2 cfu/g) and high (~2 cfu/g) levels, were enriched by two enrichment protocols; buffered peptone water (BPW) at 37 °C for 5h and 24h and modified buffered peptone water with pyruvate (mBPWp) for 5h at 37 °C followed by adding selective agents and incubating at 42 °C to 24h. Detection of added E. coli O157:H7 by real-time PCR (RTiPCR) and recovery on isolation agars was performed before and after PATHATRIX™ immunomagnetic separation (IMS). RTiPCR detection and cultural recovery of inoculated E. coli O157:H7 after 5h enrichment were poor at 0.21-0.24 cfu/g. The addition of IMS after 5h enrichment did not improve RTiPCR detection but markedly improved recovery by culturing. By extending enrichment to 24h, RTiPCR detection improved to 76% for either enrichment protocol without IMS. When 24h enrichment was followed by IMS, RTiPCR detection was also further improved. Cultural recovery after 24h enrichment was 56% and 84% without IMS and 100% and 92% after IMS for BPW and mBPWp respectively. Extended enrichment to 24h followed by IMS was found to be sensitive and reliable for detection and cultural recovery from raw ground beef using either enrichment method.

Ketamine inhibits transcription factors activator protein 1 and nuclear factor-kappaB, interleukin-8 production, as well as CD11b and CD16 expression: studies in human leukocytes and leukocytic cell lines.

BACKGROUND: Recent data indicate that ketamine exerts antiinflammatory actions. However, little is known about the signaling mechanisms involved in ketamine-induced immune modulation. In this study, we investigated the effects of ketamine on lipopolysaccharide-induced activation of transcription factors activator protein 1 (AP-1) and nuclear factor-kappaB (NF-kappaB) in human leukocyte-like cell lines and in human blood neutrophils. METHODS: Electric mobility shift assays were used to investigate ketamine's effects on nuclear binding activity of both transcription factors in U937 cells, and a whole blood flow cytometric technique was used for AP-1 and NF-kappaB determination in leukocytes. Cell lines with different expression patterns of opioid and N-methyl-D-aspartate receptors were used for reverse transcription-polymerase chain reaction to investigate receptors involved in ketamine signaling. Ketamine's effect on interleukin-8 production was assessed in a whole blood assay. RESULTS: Ketamine inhibited both transcription factors in a concentration-dependent manner. These effects did not depend on opiate or N-methyl-D-aspartate receptors. Ketamine also reduced interleukin-8 production in whole blood and expression of CD11b and CD16 on neutrophils. CONCLUSION: The immunoinhibitory effects of ketamine are at least in part caused by inhibition of transcription factors NF-kappaB and AP-1, which regulate production of proinflammatory mediators. However, signaling mechanisms different from those present in the central nervous system are responsible for ketamine-mediated immunomodulation.

Spontaneous regression of human cancer cells in vitro: potential role of disruption of Cdk1/Cdk4 co-expression.

BACKGROUND: Although well-acknowledged in vivo, spontaneous death of cancer cells in vitro is less widely appreciated. MATERIALS AND METHODS: Colony formation was studied in untreated control plates of standard clonogenic assays and measurements of actual and potential doubling times performed in asynchronous cultures of human cancer cells lines. Western blotting of lung large cell carcinoma, COR-L23 cells actively undergoing spontaneous cell death was also carried out. RESULTS: Catastrophic disintegration of mature colonies could be seen in the untreated plates of lung large cell carcinoma, H460 and colon adenocarcinoma, SW620 human cancer cell lines and a significant cell loss factor was present in the cell lines growing as adherent cells in continuous culture. Western blotting demonstrated alterations of relative cyclin dependent kinase (Cdk)1 to Cdk4 protein expression in dying COR-L23 cells. CONCLUSION: The phenomenon of spontaneous cell death should be considered a hallmark of cancer and may be the result of failure to stabilise unstable, fully developed cancer cells due to the disruption of Cdk1/Cdk4 co-expression in those cells.

Comparison of Petrifilm Staph Express Count System with the bacteriological analytical manual direct-plating method for enumeration of Staphylococcus aureus in artificially contaminated hard cheese.

The 3M Petrifilm Staph Express Count System was compared with the U.S. Food and Drug Administration's Bacteriological Analytical Manual (BAM) direct-plate count method for the enumeration of Staphylococcus aureus in 6 types of artificially contaminated hard cheese (Asiago, Cheddar, Gruyère, Parmesan, Romano, and Swiss). Five different samples of each cheese type were inoculated with S. aureus (ATCC 25923) to achieve low, medium, and high inoculum levels. S. aureus was enumerated by the Petrifilm and BAM methods, and the results were compared. Multivariate analysis of variance revealed no significant differences (P<0.05) between the 2 methods. The Petrifilm method compared favorably with the BAM procedure. The rapid method was more convenient to use, considerably faster, and less expensive to perform than the BAM method.

Phenoxybenzamine treatment can lead to loss of endothelial cell viability.

Phenoxybenzamine, an irreversible alpha-adrenoceptor antagonist, is used as a topical treatment against catecholamine-induced contraction in radial artery bypass grafts. Published data suggest that a wide range of phenoxybenzamine doses may be equally effective. This study aimed to investigate whether lower doses of phenoxybenzamine would benefit grafts by better preserving endothelium. To this end human vascular endothelial cells were isolated from sections of radial artery or saphenous vein, and treated with phenoxybenzamine for 30 min. Cells were then washed free of drug and viability assayed using a resazurin-based toxicology assay or returned to culture for assay at 24 h. Phenoxybenzamine treatment showed a dose-dependent effect on cell viability over several clinically employed concentrations. Concentrations above 0.1 mM led to a loss of viability, which became more pronounced with time. The loss of viability was shown to be independent of the carrier used, as results were identical when phenoxybenzamine was dissolved in dimethylsulphoxide, which alone did not affect viability. Changes in pH alone were also not sufficient to affect viability. In conclusion, phenoxybenzamine treatment is likely to cause damage to graft endothelium if employed at concentrations above 0.1 mM (0.03 mg/ml). Phenoxybenzamine may be safely used at lower doses with no potential loss of endothelial cell viability.

Ornithodoros moubata, a soft tick vector for Rickettsia in east Africa?

Omithodoros moubata complex (Argasidae) ticks collected from human dwellings in central Tanzania were found to carry a novel rickettsial species that clustered among the spotted fever group. Although no evidence of human infection was evident, these ticks feed primarily on man, thus providing opportunity for zoonotic infection.

Mice transgenic for monocyte-tropic HIV type 1 produce infectious virus and display plasma viremia: a new in vivo system for studying the postintegration phase of HIV replication.

To generate an in vivo system for investigating the postintegration phase of HIV-1 replication, mouse lines transgenic for a full-length infectious proviral clone of a monocyte-tropic HIV-1 isolate, HIV-1JR-CSF, were constructed. Leukocytes from two independent JR-CSF transgenic mouse lines produced HIV-1 that infected human PBMCs. Plasma viremia was detected in these mice at levels (mean, >60,000 HIV RNA copies/ml) comparable to those reported for HIV-1-infected individuals. The levels of HIV RNA in these mice increased several-fold after either treatment with the superantigen Staphylococcus enterotoxin B or infection with Mycobacterium tuberculosis. Thus, a provirus encoding a monocyte-tropic HIV-1 strain under the control of its LTR expressed as a transgene in mice can proceed through the postintegration replication phase and produce infectious virus. In addition, the presence of plasma viremia that can be monitored by measuring plasma HIV-1 RNA levels permits these mice to be used to study the impact of different interventions on modulating in vivo HIV-1 production. Therefore, these mice provide a novel manipulable system to investigate the in vivo regulation of HIV-1 production by factors that activate the immune system. Furthermore, this murine system should be useful in delineating the role of human-specific factors in modulating HIV-1 replication and investigating the in vivo therapeutic efficacy of agents that target the postintegration stages of HIV-1 replication.