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Biomedical subjects

M Davis

Publications and source records attributed to M Davis.

At least 127 records · Page 7Linked to original sources
PubMed2000

Disruption of contextual freezing, but not contextual blocking of fear-potentiated startle, after lesions of the dorsal hippocampus.

The role of the dorsal hippocampus in contextual fear conditioning was investigated with a contextual blocking paradigm. In Experiment 1, rats were given pairings of a light conditioned stimulus (CS) and footshock after preexposure either to footshock or to the context alone. The group preexposed to footshock showed poorer fear conditioning to the light CS, as measured by the fear-potentiated startle reflex. In Experiment 2, a group preexposed to footshock in the same context showed poorer fear conditioning to the light CS than did a group preexposed to footshock in a different context, indicating contextual blocking of fear-potentiated startle. In Experiment 3, lesions of the dorsal hippocampus had no effect on contextual blocking, even though contextual freezing was disrupted. The sparing of contextual blocking indicated that contextual memory was intact following hippocampal lesions, despite the disruption of contextual freezing.

Animals↗
PubMed2000

Dietary change through African American churches: baseline results and program description of the eat for life trial.

BACKGROUND: Eat for Life, a multicomponent intervention to increase fruit and vegetable (F & V) consumption among African Americans, is delivered through African American churches. METHODS: Fourteen churches were randomly assigned to one of three treatment conditions: 1) comparison; 2) culturally-sensitive multicomponent intervention with one phone call; and 3) culturally-sensitive multicomponent intervention with four phone calls. The intervention included an 18-minute video, a project cookbook, printed health education materials, and several "cues" imprinted with the project logo and a 5 A Day message. A key element of the telephone intervention was the use of motivational interviewing, a counseling technique originally developed for addictive behaviors. Major outcomes for the trial included total F & V intake, assessed by food-frequency questionnaires (FFQs) and 24-hour recalls, and serum carotenoids. Psychosocial variables assessed included outcome expectations, barriers to F & V intake, preference for meat meals, neophobia, social support to eat more F & V, self-efficacy to eat more F & V, and nutrition knowledge. RESULTS: Baseline mean F & V intakes across the three FFQs ranged from 3.45 to 4.28 servings per day. Intake based on a single 24-hour recall was 3.0 servings. Variables positively correlated with F & V intake included self-efficacy, outcome expectations, and a belief that F & V contain vitamins. Factors negatively correlated with intake include perceived barriers, meat preference, neophobia, and high-fat cooking practices. The completion rate for the first telephone counseling call was 90%. Completion rates for the remaining three calls ranged from 79% to 86%. CONCLUSION: The recruitment and intervention methods of the Eat for Life study appear promising. The telephone intervention based on motivational interviewing is potentially useful for delivering dietary counseling.

Adult↗
PubMed2000

Efficient export of the vesicular stomatitis virus G protein from the endoplasmic reticulum requires a signal in the cytoplasmic tail that includes both tyrosine-based and di-acidic motifs.

The vesicular stomatitis virus (VSV) G protein is a model transmembrane glycoprotein that has been extensively used to study the exocytotic pathway. A signal in the cytoplasmic tail of VSV G (DxE or Asp-x-Glu, where x is any amino acid) was recently proposed to mediate efficient export of the protein from the endoplasmic reticulum (ER). In this study, we show that the DxE motif only partially accounts for efficient ER exit of VSV G. We have identified a six-amino-acid signal, which includes the previously identified Asp and Glu residues, that is required for efficient exit of VSV G from the ER. This six-residue signal also includes the targeting sequence YxxO (where x is any amino acid and O is a bulky, hydrophobic residue) implicated in several different sorting pathways. The only defect in VSV G proteins with mutations in the six-residue signal is slow exit from the ER; folding and oligomerization in the ER are normal, and the mutants eventually reach the plasma membrane. Addition of this six-residue motif to an inefficiently transported reporter protein is sufficient to confer an enhanced ER export rate. The signal we have identified is highly conserved among divergent VSV G proteins, and we suggest this reflects the importance of this motif in the evolution of VSV G as a proficient exocytic protein.

Amino Acid Sequence↗
PubMed2000

Anger and cancer: an analysis of the linkages.

The purposes of this article are to review literature on anger's link to cancer, to analyze the state of the science in this area, and to propose some directions for future research. Extremely low anger scores have been noted in numerous studies of patients with cancer. Such low scores suggest suppression, repression, or restraint of anger. There is evidence to show that suppressed anger can be a precursor to the development of cancer, and also a factor in its progression after diagnosis. Some studies indicate that it may be beneficial for patients to mobilize anger to battle their cancer. However, there is a paucity of research on the outcomes of various anger interventions. Longitudinal studies that repeatedly measure anger and other moods over the disease trajectory are needed.

Adaptation, Psychological↗
PubMed2000

Proposed curriculum for an "observational" international emergency medicine fellowship program.

This article presents information on considerations involved in setting up and conducting fellowship training programs in emergency medicine (EM) for physicians from other countries. General goals for these programs are to assist in providing physicians from other countries with the knowledge and skills needed to further develop EM in their home countries. The authors report their opinions, based on their cumulative extensive experiences, on the necessary and optional structural elements to consider for international EM fellowship programs. Because of U.S. medical licensing restrictions, much of the proposed programs' content would be "observational" rather than involving direct "hands-on" clinical EM training. Due to the very recent initiation of these programs in the United States, there has not yet been reported any scientific evaluation of their structure or efficacy. International EM fellowship programs involving mainly observational EM experience can serve as one method to assist in EM development in other countries. Future studies should assess the impact and efficacy of these programs.

Curriculum↗
PubMed2000

Ruminant gastrointestinal cell proliferation and clearance of Escherichia coli O157:H7.

Human infections with Escherichia coli O157:H7 cause hemorrhagic colitis that can progress to a life-threatening sequelae. The most common mode of disease transmission is ingestion of contaminated bovine food products, and it is well established that E. coli O157:H7 is a transient member of the bovine microbiota. However, the conditions that induce acquisition and subsequent clearance of this bacterium from the ruminant gastrointestinal tract (GIT) are not understood. Evidence that the rates of epithelial cell proliferation in the lower GIT of cattle are associated with the duration animals remained E. coli O157:H7 culture positive is presented. Cattle with slower rates of intestinal cell proliferation in the cecum and the distal colon were culture positive significantly longer than cohort cattle with faster cell proliferation rates. Cell death rates (apoptotic indices) between the short- and long-term culture-positive animals were not different. Typical grain-based finishing diets and forage-based growing diets did not effect GIT cell proliferation or the duration animals remained E. coli O157:H7 culture positive. To identify a dietary intervention that would effect GIT cell proliferation, we used sheep as a model ruminant. A fasting-refeeding regime that increased the rate of GIT cell proliferation was developed. The fasting-refeeding protocol was used in cattle to test the hypothesis that feeding interventions that increase the rate of GIT cell proliferation induce the clearance of E. coli O157:H7 from the bovine GIT.

Animal Feed↗
PubMed2000

Gimme 5 fruit, juice, and vegetables for fun and health: outcome evaluation.

A theory-based multicomponent intervention (Gimme 5) was designed and implemented to impact fourth- and fifth-grade children's fruit, juice, and vegetable (FJV) consumption and related psychosocial variables. Gimme 5 was a randomized controlled intervention trial with school (n = 16 elementary) as unit of random assignment and analysis. Participants included the cohort of students who were in the third grade in the winter of 1994 and students who joined them in the fourth and fifth grades. The intervention included a curriculum, newsletters, videotapes, and point-of-purchase education. Evaluation included 7-day food records and psychosocial measures from students, telephone interviews with parents, and observational assessments. Favorable results were observed for consumption of FJV combined, FJV consumed at weekday lunch, eating FJV self-efficacy, social norms, asking behaviors, and knowledge. A theory-based school nutrition education program can help change children's FJV consumption and impact factors at home that predispose to FJV consumption, but changes were small, and their persistence is unknown.

Child↗
PubMed2000

Gimme 5 fruit and vegetables for fun and health: process evaluation.

Gimme 5 (Georgia) was a school-based nutrition education effectiveness trial to help fourth- and fifth-grade students eat more fruit, 100% juice, and vegetables (FJV). Process evaluation assessed fidelity of implementation, reach, and use of intervention materials and environmental mediators: teacher training, curriculum delivery, participation in family activities, attendance at evening point-of-purchase grocery store activities, and availability and accessibility of FJV at home. Approximately half of the curriculum activities were implemented in fourth and fifth grades. The lowest proportion completed were those most pertinent to behavior change. Eighty-seven percent of parents reported participating in homework activities with their fourth grader, 66% with fifth graders. Sixty-five percent of parents reported viewing a video with their child in both grades. Ten percent attended evening point-of-purchase grocery store activities. The low level of implementation and modest level of participation in family activities suggest that higher levels of behavior change may have occurred if exposure to the intervention had been higher.

Adult↗
PubMed2000

Bisoprolol in chronic heart failure.

The evidence for the use of beta-blockers in heart failure is substantial. Latest recommendations and guidelines suggest that most heart failure patients should be on a drug regimen of an angiotensin-converting enzyme inhibitor, diuretic and a beta-blocker. However, despite the evidence from trials, the majority of patient are not yet treated appropriately, with only 5% receiving a beta-blocker.

Adrenergic beta-Antagonists↗
PubMed2000

Predictors of physical fitness in a college sample.

The present study examined the relationships among self-reported amounts of exercise, body composition, age, weight, blood pressure, and physical fitness. Participants reported their duration and frequency of exercise, which were combined to obtain individual indexes of exercise. VO2 max predicted from a 1-mi. walk test, percent body fat via sum of skinfolds, blood pressure, and flexibility of the lower back and posterior thigh were measured. Findings indicated that age and exercise index were significant predictors of fitness for women, and percent body fat was a significant predictor for men. Results suggest individuals' exercise index moderately correlates with fitness, although it is not the only contributing factor.

Adolescent↗
PubMed2000

Ewing's sarcoma of the pelvis. Long-term survival and functional outcome.

Fifty patients with Ewing's sarcoma of the pelvis were treated using a multidisciplinary approach; followup of surviving patients averaged 137 months (range, 40-276 months). The addition of surgical resection to the multidisciplinary treatment for all patients was associated with improved survival compared with survival of patients treated with chemotherapy and radiation therapy alone; the addition of surgery to the treatment regimen of 37 patients without metastases also was associated with improved survival. There were no significant differences between the surgical and nonsurgical groups in terms of tumor size, stage of disease, patient age, duration of symptoms before diagnosis, or anatomic site. Surgery was used more often in recently treated patients, but the year of diagnosis and treatment did not significantly affect overall survival, secondary to large confidence intervals. The Short Form-36 and the Musculoskeletal Tumor Society functional evaluation instruments showed a superior level of function in the nonsurgical group, but this difference was not statistically significant. There have been many advances in the treatment of patients with Ewing's sarcoma during the past 3 decades, resulting in improved survival for patients with Ewing's sarcoma of the pelvis. The addition of surgery significantly improved survival and did not show a significant difference in functional outcome.

Adolescent↗
PubMed2000

Involvement of NMDA receptors within the amygdala in short- versus long-term memory for fear conditioning as assessed with fear-potentiated startle.

Pretraining intra-amygdala infusions of the NMDA receptor antagonist. D,L-AP5, block fear-potentiated startle in rats tested 24+ hr after training. This may reflect a failure of either acquisition or retention. To evaluate these alternatives, rats were tested for fear-potentiated startle during fear conditioning (30 light-shock pairings [0.6 mA shock]), as well as 1-30 min and 48 hr after fear conditioning. Amygdala lesions abolished fear-potentiated startle at all train-test intervals. Intra-amygdala AP5 infusions (25 nmol/side) abolished fear-potentiated startle during the long-term test and had partial effects at shorter train-test intervals. When the level of fear-potentiated startle during the short-term test was lowered to that of the 48-hr test (i.e., by training rats with a lower, 0.3 mA footshock), AP5 abolished fear-potentiated startle at each timepoint. Thus, amygdala NMDA receptors appear to participate in the initial acquisition of fear memories.

Amygdala↗