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Biomedical subjects

M Davis

Publications and source records attributed to M Davis.

At least 181 records · Page 10Linked to original sources

Results of a domestic violence training program offered to the staff of urban community health centers. Evaluation Committee of the Philadelphia Family Violence Working Group.

INTRODUCTION: Domestic violence (DV) against women often goes unrecognized by health care providers due to multiple barriers. In an effort to increase screening, identification, and referral for services, the RADAR Training Project was created for the health care staff of 12 federally qualified community health centers (CHCs). METHODS: A two-phase evaluation was conducted to assess the intervention. Phase one evaluated the health care providers' perceived knowledge and comfort pre-training, post-training, and at 3 months follow-up. The second phase included a medical chart review of 4 CHCs to assess the rates of screening, documentation of abuse, assessment of safety, and referrals for help at baseline (6 months pre-training) as compared to the intervention period (6 months post-training). RESULTS: The health care providers' perceived level of knowledge and comfort increased significantly post-training and then later decreased at 3 months follow-up. The rate of screening for DV (25% vs. 5%), suspicion of DV (6% vs. 2%), completion of safety assessments (17% vs. 5%), and referrals (4% vs. 0%) increased significantly between the intervention and baseline periods. However, the rates of documentation of abuse did not change. CONCLUSIONS: This intervention was successful in increasing provider perceived knowledge and comfort; however, comfort decreased at follow-up. Additionally, the rates of screening and referrals increased 6 months post-training. Health care provider training and support and integrated quality assurance mechanisms may be necessary to increase the overall rate of these activities, and to sustain this effort over time. Further study is needed to identify effective methods to increase provider comfort regarding DV screening.

Adolescent↗

Fifty year follow-up of a patient with central core disease shows slow but definite progression.

The follow-up of a patient with central core disease (CCD) over 50 years showed that although initially the condition was moderately non-progressive, progression of a significant degree did eventually occur. Histopathological and electron microscopic data were available from muscle biopsies carried out at the ages of 19 and 55 years, and show a marked predominance of type 1 fibres with central cores in most fibres at both ages. The four mutations within the RYR1 gene described in association with CCD and three of the more common malignant hyperthermia-associated mutations within RYR1 were not present.

DNA↗

How best to measure implementation of school health curricula: a comparison of three measures.

The impact of school health education programs is often attenuated by inadequate teacher implementation. Using data from a school-based nutrition education program delivered in a sample of fifth graders, this study examines the discriminant and predictive validity of three measures of curriculum implementation: class-room observation of fidelity, and two measures of completeness, teacher self-report questionnaire and post-implementation interview. A fourth measure, obtained during teacher observations, that assessed student and teacher interaction and student receptivity to the curriculum (labeled Rapport) was also obtained. Predictive validity was determined by examining the association of implementation measures with three study outcomes; health knowledge, asking behaviors related to fruit and vegetables, and fruit and vegetable intake, assessed by 7-day diary. Of the 37 teachers observed, 21 were observed for two sessions and 16 were observed once. Implementation measures were moderately correlated, an indication of discriminant validity. Predictive validity analyses indicated that the observed fidelity, Rapport and interview measures were significantly correlated with post-test student knowledge. The association between health knowledge and observed fidelity (based on dual observation only), Rapport and interview measures remained significant after adjustment for pre-test knowledge values. None of the implementation variables were significantly associated with student fruit and vegetable intake or asking behaviors controlling for pre-test values. These results indicate that the teacher self-report questionnaire was not a valid measure of implementation completeness in this study. Post-implementation completeness interviews and dual observations of fidelity and Rapport appear to be more valid, and largely independent methods of implementation assessment.

Child↗

Effect of darkness on acoustic startle in Vietnam veterans with PTSD.

OBJECTIVE: Exaggerated startle is a symptom of posttraumatic stress disorder (PTSD), but empirical studies have not consistently documented elevated baseline startle in PTSD. The authors proposed in a previous study that Vietnam veterans with PTSD exhibit exaggerated startle only under stressful conditions. They reported that darkness facilitated startle in humans, suggesting that the startle reflex is sensitive to the aversive nature of darkness. In the present study they tested the hypothesis that the magnitude of facilitation of startle by darkness would be greater in Vietnam veterans with PTSD than in comparison groups of subjects without PTSD. Prepulse inhibition was also investigated. METHOD: The magnitude of startle and prepulse inhibition were assessed in alternating periods of darkness and light in 19 nonmedicated Vietnam veterans with PTSD, 13 Vietnam veterans without PTSD, and 20 civilians without PTSD. RESULTS: The overall startle level was higher in the veterans with PTSD than in either of the two groups of subjects without PTSD. Startle was facilitated by darkness, and the magnitude of this facilitation was greater in the veterans with PTSD than in the civilians without PTSD, but it was not greater in the veterans without PTSD. Prepulse inhibition was not affected by darkness and did not significantly differ among groups. CONCLUSIONS: Contrary to the hypothesis, elevated sensitivity to darkness was specific to individuals with combat experience, not to individuals with PTSD, perhaps because veterans had become aversively conditioned to darkness during their combat experiences. The more general increase in startle reactivity in the veterans with PTSD is consistent with clinical observations and descriptions of symptoms in DSM-IV.

Acoustic Stimulation↗

Results of the TeachWell worksite wellness program.

OBJECTIVE: This study examined whether providing a school-based teacher wellness program enhances the impact of a health curriculum on student outcomes and improves cognitive, behavioral, and physiological outcomes among participating teachers. METHODS: Thirty-two elementary schools were randomly assigned to experimental or comparison conditions. Comparison group schools received the Gimme-5 program, a curriculum designed to increase fourth and fifty graders' consumption of fruits and vegetables. Experimental schools received Gimme-5 and the teacher wellness program, which included 54 workshops over 2 years, along with several schoolwide health activities. Physiological, behavioral, and cognitive outcomes were assessed in teachers and students. RESULTS: There was no evidence that the intervention favorably modified any student or teacher end points; nor did intervention teachers deliver the Gimme-5 program with greater fidelity than comparison teachers. CONCLUSION: Confidence in the null results is bolstered by the randomized design, baseline sample equivalence, appropriate mixed-model analyses, and lack of selective or differential attrition. Insufficient participation in the wellness program appears a likely explanation for the lack of teacher and student effects. Factors specific to the school setting and intervention may have diminished participation and, thus, intervention effects.

Adult↗

[Serum lipids and blood pressure levels in the +Mapuche population living in the Chilean region of Araucanía].

BACKGROUND: Chilean aboriginal populations (Mapuche) predominantly live in the region of Araucanía, in the southern part of the country. Their cardiovascular risk factors have not been systematically assessed. AIM: To study the prevalence of cardiovascular risk factors in the Mapuche population. SUBJECTS AND METHODS: Blood pressure, weight, height, dietary habits, fasting serum total cholesterol, HDL cholesterol and triglycerides were measured in 1.948 adults living in 28 Mapuche communities. RESULTS: Thirteen percent of males and 16% of females had high blood pressure. Body mass index was 25.5 kg/m2 in males and 28.1 kg/m2 in females. Forty five percent of women and 24% of men were classified as obese. Mean serum total cholesterol was 186.7 +/- 9.6 mg/dl, HDL cholesterol was 58.7 +/- 30.7 mg/dl, total cholesterol/HDL cholesterol was 3.4 +/- 2 and triglycerides were 155.2 +/- 91.2 mg/dl. Twenty eight percent of males and 9.6% of females smoked. CONCLUSIONS: Mapuche individuals have higher levels of HDL cholesterol a better total cholesterol/HDL cholesterol ratio and lower frequency of smoking than non aboriginal Chileans subjects.

Adult↗

Effects of simulated gastroesophageal reflux on the untraumatized rabbit larynx.

OBJECTIVE: Gastroesophageal reflux (GER) has been shown, clinically and experimentally, to cause inflammation of traumatized laryngeal mucosa. This study was performed to determine if GER causes inflammation of untraumatized laryngeal mucosa. METHOD: Sixteen adult New Zealand white rabbits underwent tube pharyngostomy under general anaesthesia without endotracheal intubation. After 7 days recovery, 1 mL/kg of normal saline or HCl (pH 1.5) with pepsin (0.3 mg/mL) was infused into the piriform sinus while the rabbit was under mild sedation: once, twice, or three times per day, for 14 consecutive days. RESULTS: Rabbits that received HCl and pepsin exhibited various degrees of apnea and coughing. Eventually, most developed biphasic stridor on exertion. Histologically, the degree of laryngeal inflammation was greatest when GER was simulated three times per day. Glottic inflammation was greatest in one rabbit, which responded to GER simulation with paroxysmal coughing. CONCLUSION: The mechanism of injury in GER laryngitis is postulated to be a combination of chemical trauma (due to HCl and pepsin) and mechanical trauma (due to an individually variable laryngeal chemoreflex). Further study of GER laryngitis in this new animal model is warranted.

Animals↗

Qualification of discordant responses in utility assessment.

In many studies of utility assessment, the discordant response rate is significantly high. Discordant responses suggest inconsistency and, in turn, suggest inaccurate measurement of personal values that can lead to erroneous medical recommendations. The most common method of dealing with these responses is to exclude them from the sample statistics as incoherent or confused respondents. This paper proposes another perspective on discordant responses. In a recent study eliciting utility values for states of health that follow stroke, we observed a high rate of discordant responses. Closer examination of these discordant responses reveals that discordant responses are not all alike. Simple qualitative and quantitative views of these differences suggest that there may be information outside the concordant population of responses, which is lost by their exclusion. In an effort to understand the elevated discordant response rate, the effect of relaxing the defining boundaries of a discordant response was explored.

Adult↗

Experiences of ethnic minority faculty employed in predominantly white schools of nursing.

This qualitative study describes the bicultural experience of ten ethnic minority faculty employed in predominately white baccalaureate and higher degree nursing programs in the Southeastern section of the United States. Seven themes emerged from the data: (a) appraising, (b) proving, (c) fitting-in, (d) defending, (e) distancing, (f) being invisible, and (g) mentoring to describe their experience. Results also provided support for the authors' generated Bicultural Systems Model which evaluates why and to what extent a particular transaction or series of transactions between the person and the environment is perceived as stressful. The general perception among participants was that they were not fully accepted in the academic setting of predominately white nursing programs. As a result, some faculty were expending energy trying to convince others of their legitimacy; while others were choosing to distance themselves from the academic setting and white colleagues. This study indicates a need for dialogue between white and ethnic minority faculty to facilitate adoption of strategies that reduce the negative effects of the bicultural phenomenon.

Adaptation, Psychological↗

Repeated stress, like vasopressin, sensitizes the excitatory effects of corticotropin releasing factor on the acoustic startle reflex.

In the rat, evidence now suggests a neurotransmitter function for the neuropeptides arginine vasopressin (AVP) and corticotropin releasing factor (CRF), implicating them in various autonomic, behavioral, and neuroendocrine responses to stress. Repeated AVP/CRF release in the pituitary portal circulation, due to stress, sensitizes and potentiates the release of ACTH from the anterior pituitary. Using a neuroanatomically well-defined behavior, the acoustic startle reflex in the rat, we sought to determine whether an interaction between AVP, CRF and stress might also occur centrally as measured by increased behavioral sensitivity to AVP or CRF given directly into the brain. The first experiment tested whether repeated intraventricular (i.c.v.) infusion of AVP would lead to an increase in the excitatory effect of a subthreshold dose of AVP on the acoustic startle reflex when infused 48 h later. Different groups of rats were infused with various doses of AVP (0.3, 3, or 30 ng) or vehicle on Day 1 and tested for startle over the next 60 min. On Day 2, 48 h later, all animals were infused with a single dose of AVP (300 pg) and tested for startle. Infusion of AVP on Day 1 did not increase startle consistently at any dose, but did lead to a sensitized excitatory effect of AVP on startle on Day 2 which was non-monotonically related to the dose of AVP given on Day 1. Experiment 2 tested whether AVP on Day 1 would sensitize the excitatory effects on startle of CRF given i.c.v. on Day 2. Different groups of rats were infused i.c.v. with various doses of AVP (10, 30, 100, 300 pg) or vehicle on Day 1. On Day 2, 48 h later, all rats were infused with a subthreshold dose of CRF (0.25 microg). Infusion of AVP on Day 1 led to a sensitized excitatory effect of CRF on startle on Day 2 which was non-monotonically related to the dose of AVP given on Day 1. In experiment 3, we tested whether footshocks given on Day 1 would sensitize the excitatory effect of CRF on startle tested 48 h later. Different groups were given footshocks (0.2, 0.4, 0.8, 1.6 mA) on Day 1. On Day 2, 48 h later, all rats were infused with a subthreshold dose of CRF (0.25 microg). Footshocks given on Day 1 led to a sensitized excitatory effect of CRF on startle on Day 2 which was non-monotonically related to the intensity of footshock on Day 1. Taken together, these results suggest that an interaction between AVP, CRF and stress may occur centrally, consistent with other studies showing similar interactions peripherally. This may provide a model system for analyzing how prior stress leads to enhanced behavioral reactions to subsequent stressors and a mechanism to explain dysregulation of the stress response.

Acoustic Stimulation↗

Evidence of contextual fear after lesions of the hippocampus: a disruption of freezing but not fear-potentiated startle.

The roles of the dorsal hippocampus and the central nucleus of the amygdala in the expression of contextual fear were assessed using two measures of conditioned fear: freezing and fear-potentiated startle. A discriminable context conditioning paradigm was developed that demonstrated both conditioned freezing and fear-potentiated startle in a context paired previously with foot shock, relative to a context in which foot shock had never been presented. Post-training lesions of the central nucleus of the amygdala completely blocked both contextual freezing and fear-potentiated startle. Post-training lesions of the dorsal hippocampus attenuated contextual freezing, consistent with previous reports in the literature; however, these same lesions had no effect on fear-potentiated startle, suggesting preserved contextual fear. These results suggest that lesions of the hippocampus disrupt the freezing response but not contextual fear itself.

Acoustic Stimulation↗

Double dissociation between the involvement of the bed nucleus of the stria terminalis and the central nucleus of the amygdala in startle increases produced by conditioned versus unconditioned fear.

The amplitude of the acoustic startle response is reliably enhanced when elicited in the presence of bright light (light-enhanced startle) or in the presence of cues previously paired with shock (fear-potentiated startle). Light-enhanced startle appears to reflect an unconditioned response to an anxiogenic stimulus, whereas fear-potentiated startle reflects a conditioned response to a fear-eliciting stimulus. We examine the involvement of the basolateral nucleus of the amygdala, the central nucleus of the amygdala, and the bed nucleus of the stria terminalis in both phenomena. Immediately before light-enhanced or fear-potentiated startle testing, rats received intracranial infusions of the AMPA receptor antagonist 2, 3-dihydroxy-6-nitro-7-sulphamoylbenzo(F)-quinoxaline (3 microg) or PBS. Infusions into the central nucleus of the amygdala blocked fear-potentiated but not light-enhanced startle, and infusions into the bed nucleus of the stria terminalis blocked light-enhanced but not fear-potentiated startle. Infusions into the basolateral amygdala disrupted both phenomena. These findings indicate that the neuroanatomical substrates of fear-potentiated and light-enhanced startle, and perhaps more generally of conditioned and unconditioned fear, may be anatomically dissociated.

6-Cyano-7-nitroquinoxaline-2,3-dione↗

Amygdala and bed nucleus of the stria terminalis: differential roles in fear and anxiety measured with the acoustic startle reflex.

Neural stimuli associated with traumatic events can readily become conditioned so as to reinstate the memory of the original trauma. These conditioned fear responses can last a lifetime and may be especially resistant to extinction. A large amount of data from many different laboratories indicate that the amygdala plays a crucial role in conditioned fear. The amygdala receives information from all sensory modalities and projects to a variety of hypothalamic and brainstem target areas known to be critically involved in specific signs that are used to define fear and anxiety. Electrical stimulation of the amygdala elicits a pattern of behaviours that mimic natural or conditioned states of fear. Lesions of the amygdala block innate or conditioned fear and local infusion of drugs into the amygdala have anxiolytic effects in several behavioural tests. Excitatory amino acid receptors in the amygdala are critical for the acquisition, expression and extinction of conditioned fear.

Amygdala↗

Anxiogenic effects of high illumination levels assessed with the acoustic startle response in rats.

Previous studies have shown that the amplitude of the acoustic startle reflex is increased by the presentation of aversive stimuli. In the present study, the amplitude of acoustic startle in rats was increased by exposure to high illumination levels. The effect was directly related to the intensity (0, 8, 70, and 700 footlamberts) of illumination (experiment I); was blocked by the anxiolytic compound buspirone (experiment II); and showed little or no habituation with repeated testing (experiment III). These results suggest that the elevation of startle amplitude by light may reflect an unconditioned anxiogenic effect of high illumination levels. The possible utility of this phenomenon as an animal model of anxiety is discussed.

Acoustic Stimulation↗

Darkness facilitates the acoustic startle reflex in humans.

The effects of darkness on startle reactivity and prepulse inhibition were investigated in two studies with 25 subjects participating in each study. Acoustic startle stimuli that were or were not preceded by an acoustic prepulse were delivered in alternating periods of complete darkness or light. In both studies, darkness significantly increased the magnitude of startle but did not affect prepulse inhibition (PPI). The PPI results suggest that darkness did not increase attention to the auditory modality, so that the startle facilitation in the dark probably did not result from an attentional process. The increased startle in the dark was significantly correlated with the intensity of subjects' fear of the dark as children based on retrospective rating scales. It is hypothesized that the startle facilitation in the dark results from a change in affect rather than from a change in attention.

Acoustic Stimulation↗