Animal models of peripheral neuropathy produced by a number of manipulations are assessed for the presence of pathologic pain states such as allodynia. Although stimulus-induced behavioral assays are ...frequently used and important to examine allodynia (ie, sensitivity to light mechanical touch; von Frey fiber test), other measures of behavior that reflect overall function are not only complementary to stimulus-induced responsive measures, but are also critical to gain a complete understanding of the effects of the pain model on quality of life, a clinically relevant aspect of pain on general function. Voluntary wheel-running activity in rodent models of inflammatory and muscle pain is emerging as a reliable index of general function that extends beyond stimulus-induced behavioral assays. Clinically, reports of increased pain intensity occur at night, a period typically characterized with reduced activity during the diurnal cycle. We therefore examined in rats whether alterations in wheel-running activity were more robust during the inactive phase compared with the active phase of their diurnal cycle in a widely used rodent model of chronic peripheral neuropathic pain, the sciatic nerve chronic constriction injury (CCI) model.
In adult male Sprague Dawley rats, baseline (BL) hindpaw threshold responses to light mechanical touch were assessed using the von Frey test before measuring BL activity levels using freely accessible running wheels (1 hour/day for 7 sequential days) to quantify the distance traveled. Running wheel activity BL values are expressed as total distance traveled (m). The overall experimental design was after BL measures, rats underwent either sham or CCI surgery followed by repeated behavioral reassessment of hindpaw thresholds and wheel-running activity levels for up to 18 days after surgery. Specifically, separate groups of rats were assessed for wheel-running activity levels (1 hour total/trial) during the onset (within first 2 hours) of either the (1) inactive (n = 8/group) or (2) active (n = 8/group) phase of the diurnal cycle. An additional group of CCI-treated rats (n = 8/group) was exposed to a locked running wheel to control for the potential effects of wheel-running exercise on allodynia. The 1-hour running wheel trial period was further examined at discrete 20-minute intervals to identify possible pattern differences in activity during the first, middle, and last portions of the 1-hour trial. The effect of neuropathy on activity levels was assessed by measuring the change from their respective BLs to distance traveled in the running wheels.
Although wheel-running distances between groups were not different at BL from rats examined during either the inactive phase of the diurnal cycle or active phase of the diurnal cycle, sciatic nerve CCI reduced running wheel activity levels compared with sham-operated controls during the inactive phase. In addition, compared with sham controls, bilateral low-threshold mechanical allodynia was observed at all time points after surgical induction of neuropathy in rats with free-wheel and locked-wheel access. Allodynia in CCI compared with shams was replicated in rats whose running wheel activity was examined during the active phase of the diurnal cycle. Conversely, no significant reduction in wheel-running activity was observed in CCI-treated rats compared with sham controls at any time point when activity levels were examined during the active diurnal phase. Finally, running wheel activity patterns within the 1-hour trial period during the inactive phase of the diurnal cycle were relatively consistent throughout each 20-minute phase.
Compared with nonneuropathic sham controls, a profound and stable reduction of running wheel activity was observed in CCI rats during the inactive phase of the diurnal cycle. A concurrent robust allodynia persisted in all rats regardless of when wheel-running activity was examined or whether they ran on wheels, suggesting that acute wheel-running activity does not alter chronic low-intensity mechanical allodynia as measured using the von Frey fiber test. Overall, these data support that acute wheel-running exercise with limited repeated exposures does not itself alter allodynia and offers a behavioral assay complementary to stimulus-induced measures of neuropathic pain.
This study examines the compensation of newspaper company chief executive officers (CEOs) and other top executives, comparing compensation with key measures of the companies’ financial performance ...and employment levels. Fixed-effect regressions found only a small relationship between CEO pay and companies’ market value for 2000 to 2013. There was no relationship between pay and return-on-assets or return-on-equity. Unobserved characteristics of individual companies are associated with CEO pay. The implications for the financial health of newspaper companies are discussed.
The Australian and New Zealand Burn Association recommend 20 minutes of cold running tap water as burn first aid. Scientific evidence for the optimal duration of treatment is limited. Our aim was to ...establish the optimal duration of cooling using cold running tap water to treat the acute burn. Partial thickness contact scald burns were induced at five sites in each of 17 pigs. Treatments with cold running tap water for 5, 10, 20, and 30 minutes were randomly allocated to different sites together with an untreated control site. In the running water 5 and 10 minute treatments intradermal temperatures rose by 1 degrees C per minute when cooling was stopped, compared with 0.5 degrees C per minute for 20 and 30 minutes duration. No differences in the surface area of each burn were noted between the five treatments on day 9. Histological analysis of burn depth on days 1 and 9 revealed that a higher proportion of burns treated for 20 and 30 minutes showed improvement compared with those treated for 5 and 10 minutes only. This difference reached statistical significance (P < .05) only in the cold running water for 20 minutes treatment arm. There was a statistically significant (P < .05) improvement in burn depth in a porcine acute scald burn injury model when the burn was treated with cold running tap water for 20 minutes as opposed to the other treatment durations. This study supports the current burn first aid treatment recommendations for the optimal duration of cooling an acute scald burn.
White-tailed deer, Odocoileus virginianus, anthrax epizootics have been frequently documented in Texas over the last two decades. Once outbreaks begin, there is evidence for the potential role of ...hematophagous flies as vectors for the disease. Hypotheses on the role of biting flies in the transmission of anthrax date back more than a century. Both laboratory experiments and field studies have provided evidence of a biting fly transmission pathway. In particular, several studies have implicated biting flies during severe wildlife outbreaks in North America. Despite these implications, there is a lack of spatial analysis relating flies and anthrax. Here we report on the spatial patterns of anthrax in white-tailed deer on a well-studied ranch with a documented anthrax history. These patterns were evaluated against the spatiotemporal patterns of biting flies during the anthrax risk period. Unbaited fly traps were used to collect flies across the study ranch from June through August 2005. Kernel density analysis confirmed biting fly hotspots concentrated in the areas with highest densities of deer carcasses. The average nearest neighbor index confirmed that deer carcasses were spatially clustered and density estimates suggest that these are in proximity to areas supporting high fly populations. Dual kernel density analysis of carcasses and deer population identified a large dry riverine habitat as a high anthrax risk. Fly catch rates across the period identified a similar pattern to the anthrax risk surface. The high overlap between areas of sustained high fly catch rates and anthrax cases does suggest a relationship warranting future research.
Burns commonly occur in children and their first aid remains inadequate despite burn prevention programmes. While scald injuries predominate, contact and flame burns remain common. Although typically ...less severe injuries overall than those in adults, hypertrophic scarring complicating both the burn wound and even donor sites occur more frequently in children. The heterogeneous nature of burn wounds, coupled with the difficulties associated with the early clinical assessment of burn depth, has stimulated the application of novel technologies to predict burn wound outcome. This review explores current best practice in the management of paediatric burns, with a focus on prevention, optimal first aid, resuscitation, burn wound prediction and wound management strategies.
Burns remain a leading cause of injury in the paediatric population in Australia despite efforts in prevention. Advances in surgical management include novel debridement methods and blood conserving ...techniques. Patients with severe burns (>20%) remain significantly more complex to manage as a result of extensive alterations in metabolic processes. There appears increasing evidence to support the use of pharmacological modulators of the hyper‐metabolic state in these patients. The management of a child with burns involves acute, subacute and long‐term planning. This holistic approach seems optimally co‐ordinated by a Burns Unit in which each discipline required to provide care to these children in order to achieve optimal outcomes is represented.
Hugh-Jones and Blackburn and Turnbull's collective World Health Organization (WHO) report did literature reviews of the theories and the bases for causes of anthrax outbreaks. Both comment on an ...often-mentioned suspicion that, even though unproven, latent infections are likely involved. Hugh-Jones suggested Gainer do an updated review of our present-day knowledge of latent infections, which was the basis for Gainer's talk at the Biology of Anthrax Conference in Bari, Italy 2019. At the Conference Gainer met Vergnaud who presented anthrax genome studies that implied that the disease might have spread throughout Asia and from Europe to North America in a short time span of three or four centuries. Vergnaud wondered if latent infections might have played a role in the process. Several other presenters at the Conference also mentioned results that might suggest the existence of latent infections. Vergnaud subsequently looked into some of the old French literature about related observations, results, and discussions of early Pasteur vaccine usage (late 1800's) and found mentions of suspected latent infections. The first part of the paper is a focused summary and interpretation of Hugh-Jones and Blackburn's and Turnbull's reviews specifically looking for suggestions of latent infections, a few additional studies with slightly different approaches, and several mentions made of presentations and posters at the Conference in Italy. In general, many different investigators in different areas and aspects of the anthrax study at the Conference found reasons to suspect the existence of latent infections. The authors conclude that the affected species most studied, including
, provide circumstantial evidence of latent infections and modified host resistance. The last part of the review explores the research needed to prove or disprove the existence of latent infections.
Even though anthrax is a disease of antiquity that has been studied for centuries, serious concerns have been raised about our understanding of its epidemiology. Since the 1960s, we have based the ...epidemiology of anthrax on the results of dose-dependent experiments, especially those involving cattle at that time. In this species the experiments demonstrated that the severity of infection was dependent upon the numbers of Bacillus anthracis spores ingested. The opinion was that ingesting only a few spores would be insufficient to cause an apparent infection; any infection that resulted would be latent (i.e., unrecognized). Based on the results of these experiments, it was accepted that the ingestion of large numbers of spores was the source of infection for hundreds of anthrax outbreaks. However, many investigations of both human and animal anthrax outbreaks have failed to identify sources of large numbers of spores, suggesting that these outbreaks are only rarely a consequence of ingestion or inhalation of large quantities of spores. This opinion piece builds upon the indirect evidence previously presented in an article focused on the existence of latent infections. Much of the evidence for the existence of latent infections was predicated upon a reduction of host resistance, which revealed how latent infections could be a source of more severe forms of the infection. That is, a latent infection can be the source of a severe infection, but the cause of the severe infection is the reduced host resistance. That first article concentrated on the arguments for latent infections, while this article concentrates on the arguments for host resistance. Host resistance is virtually impossible to measure objectively in the field. To provide a subjective measure of host resistance during anthrax outbreaks, we suggest the use of the opinions of livestock owners and or their veterinary practitioners and or field workers during investigations of anthrax outbreaks. When veterinary personal work in the field they are much like field biologists. In some ways field biologists better appreciate environmental factors, population ecology and other perspectives that are of use to epidemiologists. The more diverse the information the better the epidemiology is understood. To this effect we present our personal anecdotal and theoretical ideas from our experiences as well as a collection of bibliographic observations from others’. Our conclusions are that a combination of latent infections and reduced host resistance based on the host's relationship with its environment would better explain the epidemiology of severe infections in anthrax outbreaks for which large quantities of spores have not been located. This applies especially if the area has a history of the disease and/or if necropsies have shown the presence of latent infections in otherwise normal animals in the area and/or if environmental conditions are considered stressful and include intense insect activity.
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