1,601 research outputs found
Examining the Vulnerability of Inhibitory Control to the Impairing Effects of Alcohol
There is growing evidence that acute changes in fundamental mechanisms of impulse control contribute to the transition from social drinking to abusive drinking. One component of impulsivity concerns the ability to inhibit maladaptive behaviors (i.e., inhibitory control). Inhibitory mechanisms are reliably shown to be sensitive to the impairing effects of alcohol, and studies have begun to show that this impairment fails to recover at the same speed as other aspects of behavior. However, the degree to which inhibitory control develops tolerance to alcohol has only been examined under limited conditions. This dissertation consists of three studies examining contexts in which tolerance has been observed for a host of prototypic behaviors, and will compare the degree to which it fails to develop for inhibitory control. Study 1 examined the rate of recovery for inhibitory control compared with other behaviors as blood alcohol concentrations (BACs) declined to zero following a dose of alcohol in 24 social drinkers. Results revealed prolonged alcohol impairment of inhibitory control along the BAC curve, even as BACs approached zero. By contrast, behaviors including reaction time and motor coordination began to show recovery markedly faster, as BACs were still significantly elevated. Study 2 examined the degree to which recent drinking patterns predict acute alcohol impairment from alcohol in a group of 52 drinkers. Recent, heavy consumption predicted less impairment of motor coordination, but bore no relationship to the magnitude of impairment of inhibitory control. Study 3 examined whether increasing the stimulus strength of environmental cues signaling the need to inhibit behavior could reduce alcohol impairment of inhibitory control in 56 participants. Results showed that increasing stimuli strength reduced alcohol impairment of behavioral activation, but actually increased inhibitory failures. Taken together, the findings contribute to the growing body of evidence suggesting that inhibitory control is especially vulnerable to the impairing effects of alcohol compared with other behaviors. Indeed, these studies systematically assessed the pharmacokinetic and environmental factors that contribute to tolerance, indicating that inhibition is disrupted in circumstances under which response activation is unimpaired. The findings have important implications for understanding the behaviorally-disruptive effects of alcohol
Eschmann Introducer Through Laryngeal Mask Airway: A Cadaveric Trial of An Alternate Means of Rescue Intubation
Study Objective: Laryngeal mask airways (LMAs) are often used as airway rescue devices where laryngoscopy is difficult. The LMA does not protect the airway and is preferably replaced with a cuffed endotracheal tube. There are reports of cases where an Eschmann tracheal tube introducer (ETTI) was successfully used to bridge between a standard LMA and an endotracheal tube. This project was designed to determine whether an Eschmann stylet can reliably be passed through an LMA into the trachea as a means of rescue intubation.Methods: Nineteen emergency medicine residents and attending physicians, who were participants in a cadaveric airway course, placed and inflated a size 4 LMA (The Laryngeal Mask Company Ltd., San Diego, CA) on each of six unembalmed human cadavers in the usual fashion. They then attempted to pass a lubricated, 15 Fr, reusable, coude-tipped ETTI (Portex, Smiths Medical, Keene, NH)) through the airspace/handle of the inflated LMA. The LMA was then deflated and removed while the ETTI was held in place. Investigators then determined the location of the ETTI by laryngoscopy.Results: Of 114 attempts at the rescue procedure, 59 resulted in placement of the bougie into the trachea, yielding an overall success rate of 52% (95% CI 48%-56%). There were no significant differences in performance based on level of training of residents or years of experience of attending physicians.Conclusions: While not a primary difficult airway option, the use of a ETTI as a bridge device between LMA and endotracheal tube was successful about 50% of the time. [West J Emerg Med. 2010;11:16-19.
A Creek in Need: A Water Chemistry Analysis of a Stream Slated for Restoration (Line Creek, Schoharie County, NY)
Surface water quality may directly impact human health and the survival of aquatic life. Schoharie County is a unique laboratory for studying surface water chemistry because many creeks and streams were ravaged by large scale flooding events associated with Hurricane Irene and Tropical Storm Lee in 2011. Currently, one of the largest stream restoration projects in the US is being conducted in the Schoharie Creek watershed. One damaged stream is Line Creek, which is a small first order stream in that watershed. Line Creek was tested for sodium, chloride, alkalinity (HCO3-), hardness (CaCO3), iron, nitrite (NO2-N), nitrate (NO3-N), total and dissolved phosphorous (PO4-P), ammonia (NH3-N) and coliform bacteria. The aforementioned parameters were measured at two sites between February and May 2014 and were compared to earlier data. Data for 2014 (upstream/downstream; all values are mg/L unless otherwise noted) are: sodium 3.18/4.46; chloride 13.5/22.5; alkalinity 29.2/55.0; hardness 40.8/58.8; iron 0.296/0.354; nitrite 0.011/0.014; nitrate 0.122/0.149; total phosphorous 0.002/0.043; dissolved phosphorous 0/0.015; ammonia 0.597/0.639; coliform bacteria(CFU) 16/42. While many parameters fell within EPA guidelines for human consumption or within an accepted range for survival of aquatic life, some like iron, were too high by EPA standards, while alkalinity was too low for aquatic life to properly develop essential hard/bony body structures. This work will be discussed with respect to the larger Schoharie Creek watershed. The broad implications of the data with respect to human and aquatic life will be discussed
When do confounding by indication and inadequate risk adjustment bias critical care studies? A simulation study
Abstract
Introduction
In critical care observational studies, when clinicians administer different treatments to sicker patients, any treatment comparisons will be confounded by differences in severity of illness between patients. We sought to investigate the extent that observational studies assessing treatments are at risk of incorrectly concluding such treatments are ineffective or even harmful due to inadequate risk adjustment.
Methods
We performed Monte Carlo simulations of observational studies evaluating the effect of a hypothetical treatment on mortality in critically ill patients. We set the treatment to have either no association with mortality or to have a truly beneficial effect, but more often administered to sicker patients. We varied the strength of the treatmentâs true effect, strength of confounding, study size, patient population, and accuracy of the severity of illness risk-adjustment (area under the receiver operator characteristics curve, AUROC). We measured rates in which studies made inaccurate conclusions about the treatmentâs true effect due to confounding, and the measured odds ratios for mortality for such false associations.
Results
Simulated observational studies employing adequate risk-adjustment were generally able to measure a treatmentâs true effect. As risk-adjustment worsened, rates of studies incorrectly concluding the treatment provided no benefit or harm increased, especially when sample size was large (nâ=â10,000). Even in scenarios of only low confounding, studies using the lower accuracy risk-adjustors (AUROCâ<â0.66) falsely concluded that a beneficial treatment was harmful. Measured odds ratios for mortality of 1.4 or higher were possible when the treatmentâs true beneficial effect was an odds ratio for mortality of 0.6 or 0.8.
Conclusions
Large observational studies confounded by severity of illness have a high likelihood of obtaining incorrect results even after employing conventionally âacceptableâ levels of risk-adjustment, with large effect sizes that may be construed as true associations. Reporting the AUROC of the risk-adjustment used in the analysis may facilitate an evaluation of a studyâs risk for confounding.http://deepblue.lib.umich.edu/bitstream/2027.42/111639/1/13054_2015_Article_923.pd
Incidence of Rebound Hypertension after Discontinuation of Dexmedetomidine
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/151835/1/phar2323_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/151835/2/phar2323.pd
Initial Characterization of the FlgE Hook High Molecular Weight Complex of Borrelia burgdorferi
The spirochete periplasmic flagellum has many unique attributes. One unusual characteristic is the flagellar hook. This structure serves as a universal joint coupling rotation of the membrane-bound motor to the flagellar filament. The hook is comprised of about 120 FlgE monomers, and in most bacteria these structures readily dissociate to monomers (⌠50 kDa) when treated with heat and detergent. However, in spirochetes the FlgE monomers form a large mass of over 250 kDa [referred to as a high molecular weight complex (HMWC)] that is stable to these and other denaturing conditions. In this communication, we examined specific aspects with respect to the formation and structure of this complex. We found that the Lyme disease spirochete Borrelia burgdorferi synthesized the HMWC throughout the in vitro growth cycle, and also in vivo when implanted in dialysis membrane chambers in rats. The HMWC was stable to formic acid, which supports the concept that the stability of the HMWC is dependent on covalent cross-linking of individual FlgE subunits. Mass spectrometry analysis of the HMWC from both wild type periplasmic flagella and polyhooks from a newly constructed ÎfliK mutant indicated that other proteins besides FlgE were not covalently joined to the complex, and that FlgE was the sole component of the complex. In addition, mass spectrometry analysis also indicated that the HMWC was composed of a polymer of the FlgE protein with both the N- and C-terminal regions remaining intact. These initial studies set the stage for a detailed characterization of the HMWC. Covalent cross-linking of FlgE with the accompanying formation of the HMWC we propose strengthens the hook structure for optimal spirochete motility
Women\u27s Age of First Exposure to Internet Pornography Predicts Sexual Victimization
Increases in the availability and accessibility of Internet pornography have led growing numbers of children to become consumers of sexually explicit media. Research has identified negative behavioral and attitudinal outcomes associated with Internet pornography use in childhood and adolescence, but few studies have examined sexual victimization as a correlate. The current study aimed to examine the association between age of first Internet pornography exposure and sexual victimization. Data from 154 undergraduate women yielded several important findings. Women who viewed Internet pornography unintentionally at a younger age reported more sexual victimization. Specifically, compared to women who were first unintentionally exposed to Internet pornography at age 14 or older, women with unintentional first Internet pornography exposure before the age of 14 reported more childhood sexual abuse, sexual abuse in adulthood, and more instances of sexual coercion and aggression. Women with younger age of unintentional Internet pornography exposure also reported more interpersonal sexual objectification than women who had never viewed Internet pornography at all. Age of first intentional exposure to Internet pornography was not related to womenâs self-reported experiences of objectification, although this may be because womenâs intentional exposure tended to happen at older ages. Overall, the results of this study suggest that womenâs unintentional Internet pornography exposure at a young age may contribute to a potentially harmful sexual socialization. Early Internet pornography exposure in childhood should be considered a potential risk factor for womenâs sexual victimization
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Spatial epidemiological patterns suggest mechanisms of land-sea transmission for Sarcocystis neurona in a coastal marine mammal.
Sarcocystis neurona was recognised as an important cause of mortality in southern sea otters (Enhydra lutris nereis) after an outbreak in April 2004 and has since been detected in many marine mammal species in the Northeast Pacific Ocean. Risk of S. neurona exposure in sea otters is associated with consumption of clams and soft-sediment prey and is temporally associated with runoff events. We examined the spatial distribution of S. neurona exposure risk based on serum antibody testing and assessed risk factors for exposure in animals from California, Washington, British Columbia and Alaska. Significant spatial clustering of seropositive animals was observed in California and Washington, compared with British Columbia and Alaska. Adult males were at greatest risk for exposure to S. neurona, and there were strong associations with terrestrial features (wetlands, cropland, high human housing-unit density). In California, habitats containing soft sediment exhibited greater risk than hard substrate or kelp beds. Consuming a diet rich in clams was also associated with increased exposure risk. These findings suggest a transmission pathway analogous to that described for Toxoplasma gondii, with infectious stages traveling in freshwater runoff and being concentrated in particular locations by marine habitat features, ocean physical processes, and invertebrate bioconcentration
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