Detection of SARS-CoV-2 within the healthcare environment: a multi-centre study conducted during the first wave of the COVID-19 outbreak in England.

BACKGROUND: Understanding how severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is spread within the hospital setting is essential in order to protect staff, implement effective infection control measures, and prevent nosocomial transmission. METHODS: The presence of SARS-CoV-2 in the air and on environmental surfaces around hospitalized patients, with and without respiratory symptoms, was investigated. Environmental sampling was undertaken within eight hospitals in England during the first wave of the coronavirus disease 2019 outbreak. Samples were analysed using reverse transcription polymerase chain reaction (PCR) and virus isolation assays. FINDINGS: SARS-CoV-2 RNA was detected on 30 (8.9%) of 336 environmental surfaces. Cycle threshold values ranged from 28.8 to 39.1, equating to 2.2 x 105 to 59 genomic copies/swab. Concomitant bacterial counts were low, suggesting that the cleaning performed by nursing and domestic staff across all eight hospitals was effective. SARS-CoV-2 RNA was detected in four of 55 air samples taken <1 m from four different patients. In all cases, the concentration of viral RNA was low and ranged from <10 to 460 genomic copies/m3 air. Infectious virus was not recovered from any of the PCR-positive samples analysed. CONCLUSIONS: Effective cleaning can reduce the risk of fomite (contact) transmission, but some surface types may facilitate the survival, persistence and/or dispersal of SARS-CoV-2. The presence of low or undetectable concentrations of viral RNA in the air supports current guidance on the use of specific personal protective equipment for aerosol-generating and non-aerosol-generating procedures.

Access Matting Reduces Mixedgrass Prairie Soil and Vegetation Responses to Industrial Disturbance.

Substantial interest exists in understanding the role of low-disturbance construction methods in mitigating industrial impacts to native grassland soils and vegetation. We assessed soil and vegetation responses to conventional high-disturbance sod-stripping and revegetation on sandy soils, and the alternative practice of low-disturbance access matting to provide a temporary work surface on sandy and loamy soils. Treatments were associated with high-voltage transmission tower construction during 2014 within the Mixedgrass Prairie. High-disturbance sites were hydroseeded in May of 2015, while low-disturbance sites recovered naturally. We assessed soil physical (bulk density, water infiltration) and chemical properties (organic matter, pH, and electrical conductivity) after construction and herbage biomass for three growing seasons. Sod-stripping led to 53% greater soil bulk density and 51% less organic matter than nondisturbed controls, while water infiltration increased by 32% in these high-sand (>80%) soils. In contrast, access matting led to minimal soil property changes regardless of the texture. While total herbage biomass was unaffected by all construction treatments, sod-stripping reduced grass biomass by 80% during the first growing season, which coincided with a 119% increase in forb mass. Root biomass (0-15 cm) also declined 77% with sod-stripping. Vegetation biomass on sites with access matting remained largely unaffected by the disturbance. Overall, low-disturbance construction methods using access matting were more effective than sod-stripping in mitigating the negative impacts of industrial development on Mixedgrass soil properties, as well as vegetation biomass, and are recommended as a best management practice during industrial disturbance.

Elevated unidentified antibodies in sickle cell anaemia patients receiving blood transfusions in Cape Town, South Africa

Background. Sickle cell disease (SCD) is an inherited haemoglobinopathy in which homozygous individuals suffer from numerous complications including vaso-occlusion, infection and haemolytic anaemia. Patients therefore often require blood transfusions, which may lead to elevated levels of allogeneic antibodies. In South Africa (SA), the number of patients with SCD has risen significantly owing to migration and changing demographics, leading to an increased need for blood products.Objectives. Against the above background, to determine the incidence of alloimmunisation and the presence of clinically significant antibodies in SCD patients requiring transfusions in Cape Town, SA.Methods. Information on SCD patients receiving blood products between 2010 and 2012, including demographics, number of units transfused and the presence and type of alloantibodies, was collected. The results were compared with those for non-SCD controls who had received a similar number of transfusions.Results. Of 182 patients analysed, 91 had SCD. Twenty-two percent of the SCD patients and 13.2% of the controls had become alloimmunised (p=0.12), while the proportions of those receiving transfusions and acquiring clinically significant antibodies were similar between the two groups (p=0.17 and p=0.19, respectively). However, the total number and amount of unidentified antibodies were significantly increased in patients with SCD (p=0.02 and p<0.001, respectively).Conclusions. This study concluded that patients with SCD develop increased numbers of unidentified antibodies, which may be important in the selection of suitable donors

Sampling and inactivation of wet disseminated spores from flooring materials, using commercially available robotic vacuum cleaners.

AIMS: Four commercially available robotic vacuum cleaners were assessed for sampling efficiency of wet disseminated Bacillus atrophaeus spores on carpet, polyvinyl chloride (PVC) and laminate flooring. Furthermore, their operability was evaluated and decontamination efficiency of one robot was assessed, using a sodium hypochlorite solution. METHODS AND RESULTS: In an environmental chamber, robots self-navigated around 4 m2 of flooring containing a single contaminated 0·25 m2 tile (c. 104 spores per cm2 ). Contamination levels at predetermined locations were assessed by macrofoam swabs (PVC and laminate) or water soluble tape (carpet), before and after sampling. Robots were dismantled postsampling and spore recoveries assessed. Aerosol contamination was also measured during sampling. Robot sampling efficiencies were variable, however, robots recovered most spores from laminate (up to 17·1%), then PVC and lastly the carpet. All robots spread contamination from the 'hotspot' (all robots spread <0·6% of the contamination to other areas) and became surface contaminated. Spores were detected at low levels during air sampling (<5·6 spores per litre). Liquid decontamination inactivated 99·1% of spores from PVC. CONCLUSIONS: Robotic vacuum cleaners show promise for both sampling and initial decontamination of indoor flooring. SIGNIFICANCE AND IMPACT OF THE STUDY: In the event of a bioterror incident, e.g. deliberate release of Bacillus anthracis spores, areas require sampling to determine the magnitude and extent of contamination, and to establish decontamination efficacy. In this study, we investigate robotic sampling methods against high concentrations of bacterial spores applied by wet deposition to different floorings, contamination spread to other areas, potential transfer of spores to the operators and assessment of a wet vacuum robot for spore inactivation. The robots' usability was evaluated and how they can be employed in real life scenarios. This will help to reduce the economic cost of sampling and the risk to sampling/decontamination teams.

Relationship of pressure to be thin with gains in body weight and fat mass in adolescents.

BACKGROUND: Sociocultural pressure to be thin is commonly reported by adolescents; yet, to what extent such pressure is associated with weight gain has not been evaluated longitudinally. OBJECTIVE: Examine whether pressure to be thin was positively associated with weight and fat gain in adolescents. METHODS: Participants were 196 healthy adolescent (age 15 ± 1 years old) girls (65%) and boys of varying weights (BMI 25 ± 7 kg/m2 ) studied at baseline and 1-year follow-up. At baseline, adolescents and their mothers reported pressure to be thin by questionnaire. At baseline and follow-up, BMI was calculated, and fat mass was assessed with air displacement plethysmography. Multiple regression was used to examine associations between baseline pressure to be thin and 1-year changes in BMI and fat mass. RESULTS: Accounting for multiple covariates, including baseline BMI or fat, adolescent-reported pressure from parents and peers and mother-reported pressure toward their teen were associated with greater gains in either adolescent BMI or fat (ps < .05). Adolescent weight status was a moderator of multiple effects (ps < .05). CONCLUSIONS: Parental and peer pressure to be thin were associated with increases in BMI and fat mass during adolescence, particularly in heavier adolescents. Further research is necessary to clarify how this association operates reciprocally and to identify underlying explanatory mechanisms.

Ketoprofen pharmacokinetics of R- and S-isomers in juvenile loggerhead sea turtles (Caretta caretta) after single intravenous and single- and multidose intramuscular administration.

Ketoprofen is a nonsteroidal anti-inflammatory and analgesic agent that nonselectively inhibits cyclooxygenase, with both COX-1 and COX-2 inhibition. Recent studies on COX receptor expression in reptiles suggest that nonselective COX inhibitors may be more appropriate than more selective inhibitors in some reptiles, but few pharmacokinetic studies are available. The goal of this study was to determine single- and multidose (three consecutive days) pharmacokinetics of racemic ketoprofen administered intravenously and intramuscularly at 2 mg/kg in healthy juvenile loggerhead turtles (Caretta caretta). The S-isomer is the predominant isomer in loggerhead sea turtles, similar to most mammals, despite administration of a 50:50 racemic mixture. Multidose ketoprofen administration demonstrated no bioaccumulation; therefore, once-daily dosing will not require dose adjustment over time. S-isomer pharmacokinetic parameters determined in this study were Cmax of 10.1 µg/ml by IM injection, C0 of 13.4 µg/ml by IV injection, AUC of 44.7 or 69.4 µg*hr/ml by IM or IV injection, respectively, and T½ of 2.8 or 3.6 hr by IM or IV injection, respectively. Total ketoprofen plasma concentrations were maintained for at least 12 hr above concentrations determined to be effective for rats and humans. A dose of 2 mg/kg either IM or IV every 24 hr is likely appropriate for loggerhead turtles.

Contamination of hospital tap water: the survival and persistence of Pseudomonas aeruginosa on conventional and 'antimicrobial' outlet fittings.

BACKGROUND: Pseudomonas aeruginosa infections have been linked to contaminated hospital taps, highlighting the potential for tap outlet fittings (OF) to harbour biofilm. P. aeruginosa may be transferred to OFs via contaminated cleaning cloths. Suggested interventions include flushing regimens and alternative OF designs. AIM: To investigate the transfer of P. aeruginosa from a contaminated cleaning cloth to conventional and 'antimicrobial/antibiofilm' OFs and to determine whether this contamination persists and/or leads to contamination of tap water. METHODS: Microfibre cloths contaminated with P. aeruginosa (108 cfu/mL) were used to wipe four different types of OF [one of conventional design (OF-A) and three marketed as 'antimicrobial' and/or 'antibiofilm' (OF- B, -C and -D)]. OFs were inserted into an experimental water distribution system for up to 24 h. Survival was assessed by culture. Single and multiple water samples were collected and cultured for P. aeruginosa. FINDINGS: The median number of P. aeruginosa transferred from cloth to OF was 5.7 × 105 cfu (OF-A), 1.9 × 106 cfu (OF-B), 1.4 × 105 cfu (OF-C) and 2.9 × 106 cfu (OF-D). Numbers declined on all OFs during the 24 h period with log reductions ranging from 3.5 (OF-C) to 5.2 (OF-B; P > 0.05). All water samples delivered immediately after OF contamination contained P. aeruginosa at ≥10 cfu per 100 mL. Contamination of water delivered from OF-A persisted despite continued flushing. Water delivered from OF-B did not contain P. aeruginosa beyond the first flush. CONCLUSION: Contaminated cleaning cloths may transfer P. aeruginosa to OFs, leading to contamination of tap water. Although not removing the potential for contamination, 'antimicrobial/antibiofilm' OFs may prevent P. aeruginosa from continually contaminating water delivered from the outlet.

Persistence of influenza on surfaces.

BACKGROUND: Close contact transmission (either direct or large droplet/droplet nuclei) is considered the main driver of influenza outbreaks but there is limited information regarding the role of fomites in transmission. AIM: To investigate the surface stability of influenza strains and thereby the role of fomites in transmission. METHODS: The viability and quantitative reverse transcription-polymerase chain reaction (qt-RT-PCR) signal of five influenza strains (A/PR/8/34/H1N1, A/Cal/7/09/H1N1, A/Cal/4/09/H1N1, A/Sol/54/06/H1N1, and A/Bris/59/07/H1N1) seeded on to three surfaces (cotton, microfibre, and stainless steel) were assessed over time. Coupons of material were seeded with 10µL of a 106-108pfu/mL suspension of cell culture-derived virus stock supplemented with 0.3% bovine serum albumin. Coupons were assayed by plaque assay and qt-RT-PCR at 1, 24h, and weekly for seven weeks using a vortex-mixing elution method. FINDINGS: Viable virus was detected from coupons for up to two weeks (stainless steel) and one week (cotton and microfibre), whereas detection of viruses by PCR was made for the entire seven-week study period. No strain differences were found. Ninety-nine percent reduction values (as a function of the seeding stock) were determined to be 17.7h for cotton (R2=0.86), 34.3h for microfibre (R2=0.80), and 174.9h for stainless steel (R2=0.98). CONCLUSION: Viable influenza was recovered from surfaces for up to two weeks. By contrast, influenza could be detected by PCR for more than seven weeks. These results have important implications for determining infection control protocols, cleaning regimes and sampling methods in healthcare settings.

Induced defences alter the strength and direction of natural selection on reproductive traits in common milkweed.

Evolutionary biologists have long sought to understand the ecological processes that generate plant reproductive diversity. Recent evidence indicates that constitutive antiherbivore defences can alter natural selection on reproductive traits, but it is unclear whether induced defences will have the same effect and whether reduced foliar damage in defended plants is the cause of this pattern. In a factorial field experiment using common milkweed, Asclepias syriaca L., we induced plant defences using jasmonic acid (JA) and imposed foliar damage using scissors. We found that JA-induced plants experienced selection for more inflorescences that were smaller in size (fewer flowers), whereas control plants only experienced a trend towards selection for larger inflorescences (more flowers); all effects were independent of foliar damage. Our results demonstrate that induced defences can alter both the strength and direction of selection on reproductive traits, and suggest that antiherbivore defences may promote the evolution of plant reproductive diversity.

Impact of empiric weight-based vancomycin dosing on nephrotoxicity and mortality in geriatric patients with methicillin-resistant Staphylococcus aureus bacteraemia.

WHAT IS KNOWN AND OBJECTIVE: Few studies have evaluated the effect of vancomycin dosing on the health outcomes in geriatric patients. Data are needed to determine whether higher vancomycin dosing strategies are more effective in geriatric patients and/or lead to excessive rates of adverse events. METHODS: This study used a subset of patients aged ≥65 years from a multicentre, retrospective, cohort study of methicillin-resistant Staphylococcus aureus (MRSA) bacteraemia. Patients received ≥ 48 h of empiric vancomycin between 1 July 2002 and 30 June 2008. We compared the incidence of nephrotoxicity and in-hospital mortality in patients who received guideline-recommended dosing (at least 15 mg/kg/dose) to patients who received lower dosing. Multivariable generalized mixed-effect models were constructed to determine independent risk factors for nephrotoxicity and in-hospital mortality. RESULTS AND DISCUSSION: Half of the cohort (46% of 92 patients) received guideline-recommended dosing. Empiric use of weight-based dosing did increase the percentage of patients achieving a vancomycin trough ≥ 15 mg/L (57% vs. 42%). Nephrotoxicity occurred in 32% of patients and 26% died during their hospitalization. Guideline-recommended dosing was not associated with significant changes in nephrotoxicity (OR 1·13; 95% CI 0·40-3·19) or in-hospital mortality (OR 1·14; 95% CI 0·41-3·18) in the multivariable analysis. WHAT IS NEW AND CONCLUSION: In this study of geriatric patients, guideline-recommended dosing was not associated with significant changes in nephrotoxicity or mortality. As 40% of the patients who received guideline-recommended dosing failed to achieve a target vancomycin trough of ≥ 15 mg/L, future studies should focus on dosing strategies to increase target attainment rate.

Microbial processes in the Athabasca Oil Sands and their potential applications in microbial enhanced oil recovery.

The Athabasca Oil Sands are located within the Western Canadian Sedimentary Basin, which covers over 140,200 km(2) of land in Alberta, Canada. The oil sands provide a unique environment for bacteria as a result of the stressors of low water availability and high hydrocarbon concentrations. Understanding the mechanisms bacteria use to tolerate these stresses may aid in our understanding of how hydrocarbon degradation has occurred over geological time, and how these processes and related tolerance mechanisms may be used in biotechnology applications such as microbial enhanced oil recovery (MEOR). The majority of research has focused on microbiology processes in oil reservoirs and oilfields; as such there is a paucity of information specific to oil sands. By studying microbial processes in oil sands there is the potential to use microbes in MEOR applications. This article reviews the microbiology of the Athabasca Oil Sands and the mechanisms bacteria use to tolerate low water and high hydrocarbon availability in oil reservoirs and oilfields, and potential applications in MEOR.

Aerosol survival of Staphylococcus epidermidis.

Recent studies have suggested that aerosol dispersal might play a role in the dissemination of meticillin-resistant Staphylococcus aureus (MRSA). Relatively little has been published about the ability of staphylococci to survive in aerosols. This study measured the survival of Staphylococcus epidermidis, a surrogate for S. aureus, in aerosols and investigated the effect of relative humidity on survival. We used a Goldberg drum to assess survival at relative humidities of <20%, 40-60%, 70-80% and >90%. We controlled for the effects of aerosol dilution and physical decay by comparing the recovery of S. epidermidis with that of the aerosol-stable spores of Bacillus atrophaeus, using the ratio of their recovery rates to estimate biological degradation of S. epidermidis over time. At all relative humidities investigated 13% [95% confidence interval (CI): 10.1-16.2%] of the initial aerosol was recovered after 5h (300 min). The mean percentage survival ratio (% S. epidermidis:% B. atrophaeus) after 5h was 47% (95% CI: 33.5-60.5%). Overlapping 95% CIs of mean percentage survival ratios at each humidity level indicated that humidity did not have a significant effect on the survival in aerosol form of S. epidermidis. Additional experiments indicated that S. epidermidis was recoverable after five days at 76% humidity. The sizes of particles within the bacterial aerosol were well within the respirable range (<2.1 µm). The survival of aerosolised S. epidermidis demonstrated in this study suggests that staphylococci have the potential for aerosol dissemination in hospitals.

Isoforms of Wilms' tumor suppressor gene (WT1) have distinct effects on mammary epithelial cells.

The role of WT1 (Wilm's tumor suppressor gene) in breast cancer is controversial, with evidence for both tumor-promoting and tumor-suppressing activities. In order to address this question, we expressed different WT1 isoforms in the mammary epithelial cell line H16N-2, which does not express endogenous WT1. Cells were stably transfected with either WT1 (-Ex5/-KTS) or WT1 (+Ex5/+KTS) under the control of the inducible metallothionein promoter. Induction of WT1 (-Ex5/-KTS) upregulated p21, causing a slowing of proliferation and a G2-phase cell cycle arrest. In artificial basement membrane, the WT1 (-Ex5/-KTS) isoform promoted the appearance of highly organized acinar cellular aggregates. In contrast, WT1 (+Ex5/+KTS) had no effect on p21 or proliferation, but rather caused an epithelial-mesenchymal transition and a redistribution of E-cadherin from the cell membrane to the cytoplasm. This isoform also causes the cellular aggregates growing in artificial basement membrane to appear significantly less organized than control cells. Thus, different WT1 isoforms have distinct effects in this cell line, suggesting that depending on the ratio of WT1 isoform expression in mammary epithelial cells, WT1 could function to either promote or suppress a transformed phenotype.

Women's perceptions of support from partners, family members and close friends for smoking cessation during pregnancy--combining quantitative and qualitative findings.

This article reports on data collected as part of a four-phase study initiated to strengthen practice in the field of smoking cessation during pregnancy. It focuses on the perceived support pregnant smokers would receive for quitting smoking and how this support could be effectively used by incorporating the education of partners/family in smoking cessation intervention strategies. Both quantitative and qualitative methods were employed, and data were collected from pregnant smokers through semistructured interviews and self-completed questionnaires. From the questionnaire data, the women reported that they would receive considerable support from their partners if they decided to stop smoking. The interviews, however, revealed that this support was 'potential' rather than 'real' and that the partners mostly made 'token gestures' such as smoking outside. None of the interviewed respondents reported receiving help in educating their partner/family about the risks of active and passive smoking, thus reducing the potential positive role they could play in smoking cessation. Whilst health professionals are aware of the important role the partner/family may play in successful smoking cessation interventions, these significant others are generally not involved. This study highlights the need for consideration to be given to providing opportunities for couples to be fully involved in smoking cessation interventions outside the antenatal environment.

Correlation between neurological progression and astrocyte apoptosis in HIV-associated dementia.

The pathogenesis of HIV-associated dementia (HIVD) has been postulated to be due to the indirect effects of HIV infection, including the aberrant central nervous system production of cytokines and other neurotoxins. A correlation between the severity of dementia and production of neurotoxins in HIVD has been demonstrated. We have previously identified nonproductive HIV infection of astrocytes. Because astrocytes participate in the inactivation of neurotoxins, we hypothesize that HIV nonproductive infection of astrocytes may lead to an environment in which there is a significant level of astrocyte apoptosis and a consequent increase in the levels of neurotoxins and that this results in more rapidly progressing dementia. Postmortem brain tissue was examined from clinically well-characterized HIV-positive demented patients, HIV-positive nondemented patients, and HIV-seronegative nondemented control subjects. The HIVD group was further categorized into subjects with rapid and those with slow progression of dementia. Tissue was paraformaldehyde fixed and paraffin embedded, and 6-microm sections from the basal ganglia and mid-frontal gyrus were processed to detect apoptosis by in situ transferase dUTP nick end labeling. Astrocytes were co-localized using immunohistochemical techniques. In situ polymerase chain reaction (PCR) techniques were utilized to detect HIV DNA in astrocytes. The density of apoptotic astrocytes was significantly greater in the HIV-positive groups than in the HIV-negative group (p < 0.01). The HIVD rapid progressors had a significantly greater number of apoptotic astrocytes in the basal ganglia than did the HIVD slow progressors (p < 0.05). In addition, there were a greater number of HIV DNA-positive astrocytes, as demonstrated by in situ PCR, in the HIVD rapid progressors than in the slow progressor and HIV-nondemented groups. These data suggest that there is an increased rate of astrocyte loss in the subjects with rapidly progressive dementia, in association with an increased number of HIV DNA-positive astrocytes. The results emphasize the importance of understanding more completely the role of HIV infection of astrocytes in the neuropathogenesis of HIVD.

Immunopathogenesis of HIV-associated dementia.

This review provides a subjective analysis of the advances in our understanding of the immunopathogenesis of HIV-associated dementia that have occurred over the past 12 months. The review will focus on the following areas: (i) the role of chemokines and cytokines; (ii) the role of astrocytes, astrocyte cell death and non-productive infection of astrocytes; (iii) a model of the neuropathogenesis of HIV-associated dementia and its impact on treatment paradigms and future research. The requirements for the development of HIV-associated dementia are immunosuppression, the loss of macrophage regulation, central nervous system HIV infection of microglia and macrophages with a neurovirulent HIV strain, restricted HIV infection of astrocytes, and astrocyte cell death, all of which lead to an intracellular milieu that is neurotoxic. This cascade can be prevented and probably reversed by the use of highly active antiretroviral therapy, which controls viral replication both systemically and centrally. However, for those patients who have resistant virus and persistently high levels of replication, or who develop resistance or toxicity, other treatment strategies need to be developed. The control of excessive microglial and macrophage activation or a diminution of astrocyte and neuronal apoptosis could have benefits in terms of cognitive function. We therefore need to develop further our understanding of the immunopathogenesis of HIV-associated dementia so that we can control a number of other steps in the cascade rather than simply controlling the viral replication.

Dialysis addition of trehalose/glycerol cryoprotectant allows recovery of cryopreserved mouse spermatozoa with satisfactory fertilizing ability as assessed by yield of live young.

Mouse sperm cryopreservation provides a means for storing the genetic information in genetically modified mice (mutants, transgenics, and "knockouts") in a cost- and space-effective manner. Sperm from this species are highly sensitive to cryodamage, which has impeded their cryopreservation in the past. The cryoprotectant used in this study was 6% glycerol (0.65 M) plus 7.5% trehalose (0.22 M), which was added to a concentrated suspension of sperm from B6SJLF1/J mice in bicarbonate-free buffer by dialysis to minimize osmotic stress on the cells. Sperm suspensions were frozen in 0.25 mL straws and stored in liquid N2. Eggs were obtained from B6SJLF1/J superovulated females. For in vitro fertilization (IVF), 15-25 microL of sperm suspension post-thaw from one straw was added directly to each of three 1.5 mL drops of fertilization medium containing 30 eggs each, for 3 replicates per experiment. The fertilized eggs were scored for blastocyst formation, after which 12 blastocysts from each drop were implanted into pseudopregnant CD-1 females. The number of live pups were then scored at birth. Ten experiments yielded 21.7 +/- 1.4 (SD) blastocysts per 30 eggs inseminated (72%) and 7.3 +/- 0.4 (SD) live pups per 12 blastocysts implanted (61%). The overall yield of live pups was 44 per 100 eggs inseminated (44%). This yield should be satisfactory for maintaining a mouse strain through sperm cryostorage, with restart of the strain through IVF and embryo transfer. The method should also provide improvement in human sperm cryopreservation, as human sperm are less sensitive to cryodamage than are mouse sperm.

Herpes simplex replication and dissemination is not increased by corticosteroid treatment in a rat model of focal Herpes encephalitis.

Neurological damage in Herpes simplex type 1 encephalitis results from neuronal cell death secondary to viral invasion, and from inflammatory changes and cerebral oedema secondary to the immune response to the virus. Corticosteroids could have an important role in the management of Herpes simplex encephalitis because their anti-inflammatory action reduces cerebral oedema. However their use has been limited by concerns that their immunosuppressive actions could increase viral replication and spread. The present study examined this issue in a rat model in which injection of HSV-1 into the cervical vagus nerve produced a well-defined focal encephalitis, characterised by an orderly progression of the virus through central neural pathways connected with vagal afferent termination sites in the medulla oblongata. After injection of HSV-1, rats were treated twice a day, either with vehicle (saline, 400 microl i.p.), with acyclovir (30 mg/kg i.p.), with dexamethasone (5 mg/kg i.p.), or with both acyclovir and dexamethasone. Animals were sacrificed after 72 h, and viral load in different brain regions was quantified by computer-assisted measurement of the area occupied by immunohistochemical reaction product. Treatment with acyclovir reduced viral load to 17 +/- 5% of the saline value (P < 0.01). After dexamethasone treatment, the viral load (63 +/- 13% of the saline value) was also reduced (P < 0.05). Treatment with both acyclovir and dexamethasone reduced viral load to 26 +/- 8% of the saline value (P < 0.01 compared with saline, and P > 0.05 compared to acyclovir alone). Our results confirm the effectiveness of acyclovir in a new model of HSV-1 infection, and provide evidence that corticosteroids do not inhibit the antiviral action of acyclovir. In addition corticosteroids may decrease the extent of infection in their own right. The acute time course studied in our model parallels the time course of acute Herpes simplex encephalitis in humans. Our data suggests that corticosteroids are not detrimental when combined with acyclovir in the management of this condition.

Trace element homeostasis during continuous sedation with propofol containing EDTA versus other sedatives in critically ill patients.

OBJECTIVE: To evaluate changes in serum and urinary zinc, cobalt, copper, iron, and calcium concentrations in critically ill patients receiving propofol containing disodium edetate (disodium ethylenediaminetetraacetic acid [EDTA]) versus sedative agents without EDTA. DESIGN: This was a randomised, open-label, parallel-group study with randomisation stratified by baseline Acute Physiology and Chronic Health Evaluation (APACHE II) scores. SETTING: Intensive care units (ICU) in 23 medical centres. PATIENTS: Medical, surgical, or trauma ICU patients 17 years of age or older who required mechanical ventilator support and sedation. INTERVENTIONS: A total of 106 patients received propofol containing 0.005 % EDTA (propofol EDTA), and 104 received other sedative agents without EDTA (non-EDTA). Only the first 108 patients were assessed for urinary trace metal excretion. Twenty-four-hour urine samples were collected on days 2, 3, and 7 and every 7 days thereafter for determination of zinc, cobalt, copper, iron, and calcium excretion; EDTA levels; urine osmolality; albumin levels; and glucose levels. The first 143 patients were assessed for serum concentration of zinc, cobalt, copper, iron, and calcium; creatinine; blood urea nitrogen; and albumin at baseline and once during each 24-hour urine collection. MEASUREMENTS AND RESULTS: For the assessment of trace metals, patients receiving propofol EDTA demonstrated increased mean urinary excretion of zinc, copper, and iron compared with the normal range. All patients receiving sedatives demonstrated increased urinary excretion of zinc and copper above normal reference values. Compared with the non-EDTA sedative group, the propofol EDTA group demonstrated increased urinary excretion of zinc and iron. Mean serum concentrations of zinc and total calcium were decreased in both patient groups. Serum zinc concentrations increased from baseline to day 3 in the non-EDTA sedative group but not in the propofol EDTA group. Renal function, measured by blood urea nitrogen, serum creatinine, and creatinine clearance, did not deteriorate during ICU sedation with either regimen. CONCLUSION: This study showed that critical illness is associated with increased urinary losses of zinc, copper, and iron. Propofol EDTA-treated patients had greater urinary losses of zinc and iron and lower serum zinc concentrations compared with the non-EDTA sedative group. No adverse events indicative of trace metal deficiency were observed in either group. The clinical significance of trace metal losses during critical illness is unclear and requires further study.