Prevalence of sudden cardiac death in dogs with atrial fibrillation.

BACKGROUND: Atrial fibrillation (AF) is associated with increased risk of sudden cardiac death (SCD) in humans, independent of secondary risk factors such as thrombogenic disorders. In dogs, SCD is described in a number of heart diseases, but an association between AF and SCD is unreported. HYPOTHESIS: (a) A higher proportion of dogs with AF will experience SCD, and (b) SCD will be associated with complex ventricular arrhythmias. ANIMALS: One-hundred forty-two dogs with AF, and 127 dogs without AF. METHODS: Retrospective, multicenter, case-control study. Dogs included in the AF group were compared to a control group of dogs in sinus rhythm, matched for echocardiographic diagnosis. Descriptive statistics were used to identify proportions of each group suffering SCD, compared using chi-squared testing. Risk factors for SCD in dogs with AF were evaluated at the univariable and multivariable level using binary logistic regression. Significance was P < .05. RESULTS: A significantly higher proportion of dogs with AF suffered SCD than dogs in the control group (14.8% vs 5.5%; P = .01). Younger age at diagnosis, larger left atrial size, and a history of syncope all were independent predictors of SCD in dogs with AF (χ2 , 16.3; P = .04). CONCLUSIONS AND CLINICAL IMPORTANCE: Atrial fibrillation was associated with a higher prevalence of SCD in dogs. A history of syncope may be a useful predictor of SCD risk.

Hepatotoxicity of Cadmium Telluride Quantum Dots Induced by Mitochondrial Dysfunction.

The aim of this study was to investigate the detailed mechanisms of hepatotoxicity induced by cadmium telluride quantum dots (CdTe-QDs) in BALB/c mice after intravenous injection. The study investigated oxidative stress, apoptosis, and effects on mitochondria as potential mechanistic events to elucidate the observed hepatotoxicity. Oxidative stress in the liver, induced by CdTe-QD exposure, was demonstrated by depletion of total glutathione, an increase in superoxide dismutase activity, and changes in the gene expression of several oxidative stress-related biomarkers. Furthermore, CdTe-QD treatment led to apoptosis in the liver via both intrinsic and extrinsic apoptotic pathways. Effects on mitochondria were evidenced by the enlargement and increase in the number of mitochondria in hepatocytes of treated mice. CdTe-QDs also caused changes in the levels and gene expression of electron transport chain enzymes, depletion of ATP, and an increase in the level of the peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α), a regulator of mitochondrial biogenesis. The findings from this study suggest that CdTe-QDs-induced hepatotoxicity might have originated from mitochondrial effects which resulted in oxidative stress and apoptosis in the liver cells. This study provides insight into the biological effects of CdT-QDs at the tissue level and the detailed mechanisms of their toxicity in animals. The study also provides important data for bridging the gap between in vitro and in vivo testing and risk assessment of these NPs.

Biodistribution and Systemic Effects in Mice Following Intravenous Administration of Cadmium Telluride Quantum Dot Nanoparticles.

Quantum dots (QDs) are engineered nanoparticles (NPs) of semiconductor structure that possess unique optical and electronic properties and are widely used in biomedical applications; however, their risks are not entirely understood. This study investigated the tissue distribution and toxic effects of cadmium telluride quantum dots (CdTe-QDs) in male BALB/c mice for up to 1 week after single-dose intravenous injections. CdTe-QDs were detected in the blood, lung, heart, liver, spleen, kidney, testis and brain. Most CdTe-QDs accumulated in the liver, followed by the spleen and kidney. At high doses, exposure to CdTe-QDs resulted in mild dehydration, lethargy, ruffled fur, hunched posture, and body weight loss. Histological analysis of the tissues, upon highest dose exposures, revealed hepatic hemorrhage and necrotic areas in the spleen. The sera of mice treated with high doses of CdTe-QDs showed significant increases in alanine aminotransferase (ALT), aspartate aminotransferase (AST), and total bilirubin levels, as well as a reduction in albumin. CdTe-QD exposure also led to a reduced number of platelets and elevated total white blood cell counts, including monocytes and neutrophils, serum amyloid A, and several pro-inflammatory cytokines. These results demonstrated that the liver is the main target of CdTe-QDs and that exposure to CdTe-QDs leads to hepatic and splenic injury, as well as systemic effects, in mice. By contrast, cadmium chloride (CdCl2), at an equivalent concentration of cadmium, appeared to have a different pharmacokinetic pattern from that of CdTe-QDs, having minimal effects on the aforementioned parameters, suggesting that cadmium alone cannot fully explain the toxicity of CdTe-QDs.

Nursing students practice primary fire prevention.

UNLABELLED: The purpose of this project was to evaluate a standardized, interactive, home fire safety program for elementary school students. BACKGROUND: Senior baccalaureate nursing students in their pediatric clinical rotation taught burn prevention techniques using Hazard House, a model house filled with common household fire hazards (Hazard House, 2006, Ref. 1). Elementary school students were encouraged to identify the hazards and discuss ways in which the house could be made safer. Local firemen then briefly presented what to do if a fire occurred, how firemen may look during a rescue, and the importance of working smoke alarms in the home. METHODS: A pretest-posttest design was used to examine the effectiveness of an educational intervention. The three groups of participants included 128 kindergarten students, 311 students in grades 1-2, and 61 students in grades 3-4. The tests and interventions were tailored appropriately for each age group. RESULTS: There was no difference in pre- and post-test scores for the students in kindergarten and grades 3-4 (p>0.05). However, there was a significant difference for students in grades 1-2 (p<0.001). CONCLUSION: It is important for nurses to assess for and teach about fire injury prevention to prevent potentially devastating irreversible injuries. The results suggest that the educational intervention was effective in improving the understanding of fire safety for students in grades 1-2. Future studies may need to include a larger sample of students for the other grades.

Altered olfactory receptor neuron responsiveness is correlated with a shift in behavioral response in an evolved colony of the cabbage looper moth, Trichoplusia ni.

There is little understanding of how sex pheromone blends might change during speciation events. For the cabbage looper, Trichoplusia ni, there is a mutant laboratory strain that has exhibited characteristics of a shift to a new pheromone blend. Mutant females produce a blend that is significantly different from wild-type females in having a much higher proportion of a minor pheromone component and lower quantity of the major component. Males in this colony have changed over the years to become more broadly tuned and fly upwind equally well to both the wild-type and mutant female pheromone blends. They also exhibit reduced overall sensitivity to pheromone, flying upwind to either blend at a lower success rate than is typical when wild-type males respond to the wild-type blend. Using single-cell recordings, we examined the olfactory receptor neurons (ORNs) of males from evolved and wild-type colonies for evidence of changes in response characteristics that might explain the above-described behavioral evolution. We found that in evolved-colony males the ORNs tuned to the major sex pheromone component exhibited a somewhat lower responsiveness to that compound than the ORNs of wild-type males. In addition, the minor pheromone component, emitted at excessively high rates by mutant females, elicited a drastically reduced ORN responsiveness in evolved-colony males compared to wild-type males. This alteration in ORN responsiveness may be responsible for allowing evolved males to tolerate the excessive amounts of the minor pheromone component in the mutant female blend, which would normally antagonize the upwind flight of unevolved males. Thus, peripheral olfactory alterations have occurred in T. ni males that are correlated with the evolution of the more broadly tuned, but less sensitive, behavioral response profile.

Antennal lobe projection destinations of Helicoverpa zea male olfactory receptor neurons responsive to heliothine sex pheromone components.

We used single sensillum recordings to define male Helicoverpa zea olfactory receptor neuron physiology followed by cobalt staining to trace the axons to destination glomeruli of the antennal lobe. Receptor neurons in type A sensilla that respond to the major pheromone component, (Z)-11-hexadecenal, projected axons to the cumulus of the macroglomerular complex (MGC). In approximately 40% of these sensilla a second receptor neuron was stained that projected consistently to a specific glomerulus residing in a previously unrecognized glomerular complex with six other glomeruli stationed immediately posterior to the MGC. Cobalt staining corroborated by calcium imaging showed that receptor neurons in type C sensilla sensitive to (Z)-9-hexadecenal projected to the dorsomedial posterior glomerulus of the MGC, whereas the co-compartmentalized antagonist-sensitive neurons projected to the dorsomedial anterior glomerulus. We also discovered that the olfactory receptor neurons in type B sensilla exhibit the same axonal projections as those in type C sensilla. Thus, it seems that type B sensilla are anatomically type C with regard to the projection destinations of the two receptor neurons, but physiologically one of the receptor neurons is now unresponsive to everything except (Z)-9-tetradecenal, and the other responds to none of the pheromone-related odorants tested.