Evidence for widespread changes in the structure, composition, and fire regimes of western North American forests.

Implementation of wildfire- and climate-adaptation strategies in seasonally dry forests of western North America is impeded by numerous constraints and uncertainties. After more than a century of resource and land use change, some question the need for proactive management, particularly given novel social, ecological, and climatic conditions. To address this question, we first provide a framework for assessing changes in landscape conditions and fire regimes. Using this framework, we then evaluate evidence of change in contemporary conditions relative to those maintained by active fire regimes, i.e., those uninterrupted by a century or more of human-induced fire exclusion. The cumulative results of more than a century of research document a persistent and substantial fire deficit and widespread alterations to ecological structures and functions. These changes are not necessarily apparent at all spatial scales or in all dimensions of fire regimes and forest and nonforest conditions. Nonetheless, loss of the once abundant influence of low- and moderate-severity fires suggests that even the least fire-prone ecosystems may be affected by alteration of the surrounding landscape and, consequently, ecosystem functions. Vegetation spatial patterns in fire-excluded forested landscapes no longer reflect the heterogeneity maintained by interacting fires of active fire regimes. Live and dead vegetation (surface and canopy fuels) is generally more abundant and continuous than before European colonization. As a result, current conditions are more vulnerable to the direct and indirect effects of seasonal and episodic increases in drought and fire, especially under a rapidly warming climate. Long-term fire exclusion and contemporaneous social-ecological influences continue to extensively modify seasonally dry forested landscapes. Management that realigns or adapts fire-excluded conditions to seasonal and episodic increases in drought and fire can moderate ecosystem transitions as forests and human communities adapt to changing climatic and disturbance regimes. As adaptation strategies are developed, evaluated, and implemented, objective scientific evaluation of ongoing research and monitoring can aid differentiation of warranted and unwarranted uncertainties.

Decontaminating N95 respirators during the COVID-19 pandemic: simple and practical approaches to increase decontamination capacity, speed, safety and ease of use.

BACKGROUND: The COVID-19 pandemic has caused a severe shortage of personal protective equipment (PPE), especially N95 respirators. Efficient, effective and economically feasible methods for large-scale PPE decontamination are urgently needed. AIMS: (1) to develop protocols for effectively decontaminating PPE using vaporized hydrogen peroxide (VHP); (2) to develop novel approaches that decrease set-up and take-down time while also increasing decontamination capacity; (3) to test decontamination efficiency for N95 respirators heavily contaminated by make-up or moisturizers. METHODS: We converted a decommissioned Biosafety Level 3 laboratory into a facility that could be used to decontaminate N95 respirators. N95 respirators were hung on metal racks, stacked in piles, placed in paper bags or covered with make-up or moisturizer. A VHP® VICTORY™ unit from STERIS was used to inject VHP into the facility. Biological and chemical indicators were used to validate the decontamination process. FINDINGS: N95 respirators individually hung on metal racks were successfully decontaminated using VHP. N95 respirators were also successfully decontaminated when placed in closed paper bags or if stacked in piles of up to six. Stacking reduced the time needed to arrange N95 respirators for decontamination by approximately two-thirds while almost tripling facility capacity. Make-up and moisturizer creams did not interfere with the decontamination process. CONCLUSIONS: Respirator stacking can reduce the hands-on time and increase decontamination capacity. When personalization is needed, respirators can be decontaminated in labelled paper bags. Make up or moisturizers do not appear to interfere with VHP decontamination.

Use, re-use or discard? Quantitatively defined variance in the functional integrity of N95 respirators following vaporized hydrogen peroxide decontamination during the COVID-19 pandemic.

BACKGROUND: Coronavirus disease 2019 has stretched the ability of many institutions to supply needed personal protective equipment, especially N95 respirators. N95 decontamination and re-use programmes provide one potential solution to this problem. Unfortunately, a comprehensive evaluation of the effects of decontamination on the fit of various N95 models using a quantitative fit test (QNFT) approach is lacking. AIMS: To investigate the effects of up to eight rounds of vaporized hydrogen peroxide (VHP) decontamination on the fit of N95 respirators currently in use in a hospital setting, and to examine if N95 respirators worn by one user can adapt to the face shape of a second user with no compromise to fit following VHP decontamination. METHODS: The PortaCount Pro+ Respirator Fit Tester Model 8038 was used to quantitatively define functional integrity, measured by fit, of N95 respirators following decontamination with VHP. FINDINGS: There was an observable downward trend in the functional integrity of Halyard Fluidshield 46727 N95 respirators throughout eight cycles of decontamination with VHP. Functional integrity of 3M 1870 N95 respirators was reduced significantly after the respirator was worn, decontaminated with VHP, and then quantitatively fit tested on a second user. Furthermore, inconsistencies between qualitative fit test and QNFT results were uncovered that may have strong implications on the fit testing method used by institutions. CONCLUSIONS: The data revealed variability in the functional integrity of different N95 models after VHP decontamination, and exposed potential limitations of N95 decontamination and re-use programmes.

The effects of sulforaphane on canine osteosarcoma proliferation and invasion.

Recent evidence in in vitro and in vivo models suggests that sulforaphane (SFN), found in raw cruciferous vegetables, may have utility in chemoprevention, as an antineoplastic agent and as a free radical scavenger. The effects of SFN alone or with doxorubicin on cell viability were examined, as well as cell cycle kinetics, invasion capabilities and apoptosis in three canine osteosarcoma cell line (D17, OS 2.4 and HMPOS). Results showed that SFN could not induce cell death at potentially physiological concentrations (<50 µM), but significantly diminished cell invasion and downregulation of focal adhesion kinase (FAK) signaling. Modest cell cycle changes were observed in each cell line. When doxorubicin was used in conjunction with SFN, there was a protective effect to doxorubicin-induced cytotoxicity in D17 and OS 2.4 cells. Further studies examining SFN as a supplement are warranted, particularly in light of pro-proliferative and cytoprotective properties in canine osteosarcoma.

Influence of endurance and sprinting exercise on plasma adiponectin, leptin and irisin concentrations in racing Greyhounds and sled dogs.

OBJECTIVE: The objective of this study was to assess the effects of both short-term anaerobic exercise and long-term aerobic exercise on leptin, adiponectin and irisin concentrations in both sprint and endurance canine athletes. DESIGN: Prospective field trial repeated measures. The 25 racing Greyhounds were run over 400 m, with blood samples collected prior to exercise and at 10 min and 120 min after exercise. The 16 sled dogs were run an average of 3.5-5 h/day on 5 out of 8 days of stage stop racing competition, with assessment on days 0, 2 and 8. RESULTS: Baseline leptin concentrations were found to be lower than previously recorded values of domestic dogs, possibly because of a lower body fat content in athletes, with concentrations in sled dogs being slightly higher than those in Greyhounds. Baseline adiponectin concentrations in both groups of dogs, on average, were lower than most previously recorded values in domestic dogs; although unexpected, these findings may be attributed to differences in body fat content of the study population. CONCLUSION: Endurance exercise in sled dogs resulted in a persistent decrease in leptin that appears to be independent of race-associated weight loss, with no appreciable changes in adiponectin or irisin concentrations. The anaerobic exercise of Greyhounds produced no detectable changes in leptin and adiponectin concentrations; however, a significant rise in irisin 10 min post-exercise may be a compensatory mechanism for restoration of ATP homeostasis in skeletal muscle.

The 5-lipoxygenase inhibitor tepoxalin induces oxidative damage and altered PTEN status prior to apoptosis in canine osteosarcoma cell lines.

The 5-lipoxygenase (5-LOX) inhibitor tepoxalin has been shown to slow canine osteosarcoma (OSA) tumour xenografts growth, yet the mechanisms are poorly elucidated. Further examination of tepoxalin in canine OSA cell lines shows that tepoxalin treated cells undergo apoptosis through caspase-3 activation and annexin staining. Interestingly, apoptosis is superseded by an increase in reactive oxygen species (ROS), as measured by activation of dihydrorhodamine 123 and mitosox. This increase in ROS appears to be related to the 5-LOX inhibitor regardless of cellular 5-LOX status, and was not observed after treatment with the tepoxalin metabolite RWJ20142. Additionally, 5-LOX inhibition by tepoxalin appears to increase phosphatase and tensin (PTEN) homolog activity by preventing its alkylation or oxidation. PTEN modification or inhibition allows phosphoinositide-3 (PI3) kinase activity thereby heightening activation of protein kinase B (AKT) phosphorylation. Our data suggest that off target oxidation and LOX inhibition play roles in the apoptotic response.

Plasma vitamin D metabolites and C-reactive protein in stage-stop racing endurance sled dogs.

BACKGROUND: Dogs are a unique model for examining the effects of exercise on vitamin D status because of their lack of vitamin D synthesis by UV exposure. In addition, the inflammatory response may be associated with hypovitaminosis D. OBJECTIVES: To investigate the effects of several days of endurance exercise on plasma vitamin D (25-(OH)D3, 24,25-(OH)D3 and 1,25(OH)D3) and serum C-reactive protein (CRP) concentrations in stage-stop racing sled dogs. ANIMALS: 12 racing sled dogs and 8 control dogs. METHODS: Blood was collected before the race and immediately after racing on days 2 and 8. Plasma vitamin D metabolites and serum CRP concentrations were measured. RESULTS: Racing dogs showed a significant increase in 25(OH)D3 on day 2 (P = .027) and day 8 of the race (P < .001), whereas no increases were observed in control dogs. The plasma concentration of 24,25(OH)D3 showed a significant increase by day 8 (P < .001). There were no significant changes in 1,25(OH) D3 concentrations across all time points and groups. Racing dogs had significantly increased CRP concentrations by day 2 (39.3 ± 30.1 µg/mL; P < .001). CONCLUSIONS AND CLINICAL IMPORTANCE: Increases in vitamin D metabolites as well as increases in CRP concentrations were observed in racing sled dogs. This finding was contrary to the hypothesis that decreases in vitamin D status in athletes may be related to the acute phase inflammatory response during exercise. In addition, the increased 24,25(OH)D3 concentrations compared to what is observed in other species suggests metabolic variations in dogs that lead to enhanced disposal of vitamin D.

Characterization of a novel alphaherpesvirus associated with fatal infections of domestic rabbits.

A virus was found to be associated with a severe disease affecting rabbits on a farm near Anchorage, Alaska. Extracts from the skin of infected rabbits produced syncytia and cell lysis in cultured rabbit skin, rabbit kidney, and Vero cells. Examination of the infectious agent by electron microscopy revealed an icosahedral nucleocapsid surrounded by an envelope with a diameter of about 120 nm, suggesting that it was a herpesvirus. The viral genome was determined to be composed of double-stranded DNA of 120-130 kbp. PCR using degenerate primers to conserved herpesvirus genes was used to amplify sequences from purified viral DNA. Sequencing of these products allowed the design of specific primers so that complete sequence data for a number of genes could be determined. Analysis of these data indicated that the virus is most closely related to bovine herpesvirus 2. The next most closely related viruses are human herpesviruses 1 and 2, and a number of cercopithecine herpesviruses. Experimental exposure of domestic rabbits to the isolate resulted in severe clinical disease and necrosis in the spleen and lymph node. In addition, viral DNA was identified in a variety of tissues by PCR, consistent with a systemic infection. Taken together, these data suggest that this virus is highly pathogenic for domestic rabbits and belongs to the family Herpesviridae, subfamily Alphaherpesvirinae, genus Simplexvirus.

Pitfalls in the CT diagnosis of appendicitis.

CT evaluation of appendicitis represents an increasingly common emergency room request. While the overall accuracy of CT is high, numerous pitfalls exist which may deceive radiologists, resulting in a missed diagnosis of appendicitis. The inflamed appendix may be unusual in its location, or may appear normal if only a small portion of the distal appendix is involved (tip appendicitis). In a patient with a history of appendectomy, inflammation of the appendiceal stump may be easily missed. Appendicitis may closely mimic small bowel obstruction, or gynaecological disease, especially after perforation has occurred. Even a misleading clinical history may lead the radiologist's eye astray. This pictorial review demonstrates these and other potential radiological pitfalls, and includes important points for the accurate diagnosis of appendicitis.

Effects of granulocyte colony-stimulating factor on hyperoxia-induced lung injury in newborn piglets.

Granulocyte colony-stimulating factor (G-CSF) increases the concentration and activation of neutrophils in the peripheral blood and has been used to prevent late-onset infection in premature infants. However, if G-CSF also augmented the inflammatory response in the lung, the incidence and severity of acute and chronic lung injury might be expected to increase. Using a newborn piglet model of acute lung injury, we examined the effects of rhG-CSF (recombinant-metHuG-CSF) on lung injury. Thirty-three newborn piglets were studied as follows: 1). Unventilated controls; 2). normally ventilated (PaCO2 = 35-45 torr) with room air(RA) for 48 h; 3). normally ventilated with RA for 48 h and received rhG-CSF (10 mg/kg/dose IV) at 0, 12, 24, and 36 h; 4). hyperventilated (PaCO2 = 15-25 torr) with 100% O2 for 48 h; 5) hyperventilated with 100% O2 for 48 h and received rhG-CSF (10 mg/kg/dose IV) at 0, 12, 24 and 36 h. Complete blood counts and and differentials were performed at 0, 24, and 48 h. Animals were sacrificed at 48 h, lungs were removed en bloc, and bronchoalveolar lavage (BAL) was performed. Total blood white blood cells and neutrophil counts increased significantly over 48 h in animals who received rhG-CSF either with normoventilation (p <0.0001) or hyperventilation with 100% O2 (p <0.003), and did not change significantly in the other experimental groups. However, there were no significant differences in BAL total cell counts, neutrophil chemotaxis activity, total protein, or albumin concentrations among the groups. Despite significantly increasing peripheral neutrophil counts, rhG-CSF did not potentiate acute lung injury or inflammation. This suggests that prophylactic administration strategies using rhG-CSF to prevent sepsis in premature infants should not increase the risk for developing acute and chronic lung disease.

The experiences and challenges of informal caregivers: common themes and differences among whites, blacks, and hispanics.

PURPOSE: This study examined commonalities and differences in the experiences and challenges of White, Black, and Hispanic informal caregivers in New York, NY. DESIGN AND METHODS: A randomly selected representative cross-section of 2,241 households was contacted through telephone interviews. Complete data were available for 380 eligible participants, who were classified as White (n = 164), Black (n = 129) and Hispanic (n = 87). Descriptive, bivariate, and multivariate analyses were conducted to examine differences in caregiving intensity, reported difficulty with providing care, and having unmet needs with care provision. RESULTS: Over 70% of caregivers had no help from formal caregivers, even though over 80% had been providing care for at least 1 year, and 40% had been providing this care for 20 or more hr per week. Compared with White caregivers, Black caregivers were more likely to provide higher intensity care, to report having unmet needs with care provision, and to experience increased religiosity since becoming caregivers, but were less likely to report difficulty with providing care. Hispanic caregivers were more likely than White caregivers to have help from formal caregivers and to experience increased religiosity since becoming caregivers. IMPLICATIONS: Although many similarities exist in the experiences and challenges of informal caregivers, gaining insight from different populations of family caregivers would help program planners, policy makers, and formal caregivers to develop and implement culturally sensitive programs and policies that are supportive of the needs of these caregivers in their ever-expanding roles. Future efforts also should focus on exploring the potentially significant role that community resources, in particular, religious institutions, could play in providing outreach and support to racial/ethnic minority caregivers.

Recombinant human superoxide dismutase enhances the effect of inhaled nitric oxide in persistent pulmonary hypertension.

We investigated the pulmonary vascular effects of superoxide dismutase (SOD) alone and in combination with inhaled nitric oxide (iNO) in newborn lambs with persistent pulmonary hypertension (PPHN) following prenatal ligation of the ductus arteriosus. In in vitro experiments, pretreatment with SOD significantly enhanced vascular relaxation in response to the NO donor S-nitrosyl-acetylpenicillamine (SNAP) in fifth-generation pulmonary arteries isolated from lambs with PPHN. In vivo treatment of fully instrumented newborn lambs with a single intratracheal dose of recombinant human CuZn SOD (rhSOD; 5 mg/kg) produced selective dilation of the pulmonary circulation. Further studies, of the combination of rhSOD and iNO, showed enhancement of the pulmonary vascular effects of iNO after brief periods of inhalation of 5 ppm and 80 ppm NO. We conclude that rhSOD reduces pulmonary vascular resistance and facilitates the action of iNO in a lamb model of PPHN. This suggests that rhSOD may prove to be an effective adjunctive treatment for newborns with PPHN.

Hands on/hands off: why health care professionals depend on families but keep them at arm's length.

The authors assert that a system that requires ever greater direct and indirect participation from families must change the negative presumption that families equal trouble to one that acknowledges legitimate family interests in decision making and care delivery and treats families as partners in caregiving.

Mutational analysis of Escherichia coli topoisomerase IV. I. Selection of dominant-negative parE alleles.

In order to define regions of ParE, one of the two subunits of topoisomerase IV, that are involved in catalysis during topoisomerization, we developed a selection procedure to isolate dominant-negative parE alleles. Both wild-type parC and mutagenized parE were expressed from a tightly-regulated lac promoter on a moderate-copy plasmid. Mutated parE alleles were rescued from those plasmids that caused IPTG-dependent cell death. The mutant ParE proteins could be divided into two groups when reconstituted with ParC to form topoisomerase IV, those that elicited hyper-DNA cleavage and those that affected covalent complex formation.

Interaction of temperature, humidity, driver preferences, and refrigerant type on air conditioning compressor usage.

Recent studies have shown large increases in vehicle emissions when the air conditioner (AC) compressor is engaged. Factors that affect the compressor-on percentage can have a significant impact on vehicle emissions and can also lead to prediction errors in current emissions models if not accounted for properly. During 1996 and 1997, the University of California, Riverside, College of Engineering-Center for Environmental Research and Technology (CE-CERT) conducted a vehicle activity study for the California Air Resources Board (CARB) in the Sacramento, CA, region. The vehicles were randomly selected from all registered vehicles in the region. As part of this study, ten vehicles were instrumented to collect AC compressor on/off data on a second-by-second basis in the summer of 1997. Temperature and humidity data were obtained and averaged on an hourly basis. The ten drivers were asked to complete a short survey about AC operational preferences. This paper examines the effects of temperature, humidity, refrigerant type, and driver preferences on air conditioning compressor activity. Overall, AC was in use in 69.1% of the trips monitored. The compressor was on an average of 64% of the time during the trips. The personal preference settings had a significant effect on the AC compressor-on percentage but did not interact with temperature. The refrigerant types, however, exhibited a differential response across temperature, which may necessitate separate modeling of the R12 refrigerant-equipped vehicles from the R134A-equipped vehicles. It should be noted that some older vehicles do get retrofitted with new compressors that use R134A; however, none of the vehicles in this study had been retrofitted.

Home sweet hospital: the nature and limits of private responsibilities for home health care.

Family caregivers, often called "informal" caregivers, are the unpaid relatives, partners, or close friends who provide directly or manage the health care for individuals who are seriously ill or disabled. As a result of changes in the American health care system, family caregivers confront increasing responsibilities, burdens, and challenges. However, there are limits to family responsibility for caregiving, and whereas families may take the first step toward accepting responsibility for home care, professionals and institutions bear continuing responsibility. Public policies and programs have an enormous impact on the availability of home care assistance and services, the family's ability to afford and provide home care, and a caregiver's continued participation in the workforce. One of the major goals for the future of home care should be to recognize and respond appropriately to diverse family structures, strengths and limitations, and needs.