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Biomedical subjects

H Davis

Publications and source records attributed to H Davis.

At least 109 records · Page 6Linked to original sources
PubMed1993

Determinants of left ventricular mass in normotensive children.

Left ventricular hypertrophy has been shown to be an independent predictor of cardiovascular morbidity and mortality. Few studies have examined the determinants of left ventricular mass (LVM) in normotensive children. Eight-four healthy children, blacks and whites, girls and boys, between 6 and 18 years of age, all with positive family histories of essential hypertension, participated in the study. Demographic and anthropometric characteristics, physical activity, and hemodynamic responses at rest and in response to the stress of forehead cold stimulation and a challenging video game were related to M-mode echocardiographic determined LVM indexed by two indices of body habitus. Hierarchical stepwise multiple regression analysis indicated that the significant independent correlates of LVM per body surface area were gender (boys were greater), baseline systolic blood pressure and heart rate, a physical activity index (sweat episodes per week) and peak systolic blood pressure responses to the forehead cold stressor (final model r2 = 0.49). For LVM/height2.7 significant independent correlates were adiposity index (weight z score--height z score), gender (boys were greater), age, resting systolic pressure, and systemic vascular resistance reactivity to forehead cold stimulation (final model r2 = 0.42). These findings with normotensive children corroborate other findings that have typically involved hypertensive children, indicating that resting heart rate and systolic pressure, gender, and adiposity are early determinants of LVM indices in children. In addition, the current findings indicate that hemodynamic responses to stress also appear to play a role in the early development of LVM.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1993

Evaluation of the Children's Activity Rating Scale (CARS) in young children.

We describe the daily activity patterns and the between-day and -year reliabilities of the Children's Activity Rating Scale (CARS) measured in 180 Anglo-, African-, and Mexican-American children aged 3 or 4 yr. Reliabilities were assessed at up to 11 measurement periods over 3 yr. CARS scores were measured by two trained observers (alternating 2-h shifts) up to 12 working hours. There were no significant ethnic or day of week differences in the activity levels. Males had higher mean activity levels than females and higher activity was performed in the summer and fall than the spring or winter. The all-measurements reliability for a mean of 5.34 d of observation over the 3 yr of measurement was 0.57. The reliability across all days and years of measurement was 0.73. The highest level of reliability (0.75) was found for the percent of minutes spent at CARS levels 3, 4, or 5 followed by an intraclass correlation of 0.74 for percent of minutes spent at CARS levels 4 or 5. These data support the utility of using the CARS as a measure of physical activity in younger children from different ethnic groups.

Activities of Daily Living↗
PubMed1993

Reliability and variability of indicators of heart-rate monitoring in children.

We describe the daily heart-rate patterns and the between-day and within-day reliabilities of several heart rate indicators measured in 131 Anglo-, African-, and Mexican-American children aged 5-7 yr. Heart rates were measured over 12 waking hours with a Quantum XL Telemetry heart rate monitor. The percent of heart rates 25% above resting heart rate, an index of physical activity heart rate (PAHR-25 index), was found to have the highest within-day (0.92) and between-day (0.81) reliabilities. The Spearman-Brown prophecy formula indicated that only 9.3 h of observation would be needed to maintain a within-day reliability of 0.90. The percentage of heart rates 50% above resting heart rate (PAHR-50) was found to have slightly lower within-day (0.88) and between-day (0.56) reliability. Principal components analysis revealed that the PAHR-25 and PAHR-50 indicies only had one component throughout the day. The PAHR-25 and PAHR-50 indicies were weakly correlated with age, suggesting that they may be good indicators of relative PAHR. Male children had higher (P < or = 0.025) PAHR-25 index scores than females. There were no gender or ethnic differences in the PAHR-50 index.

Black or African American↗
PubMed1992

Structural alterations in retinal tissues from rats deficient in vitamin E and selenium and treated with hyperbaric oxygen.

Vitamin E and selenium play key roles in preventing in vitro lipid peroxidation and free radical damage to retinal tissues. In this research, we studied the effects of hyperbaric oxygen on retinal structure in rats fed diets deficient in vitamin E and/or selenium. We also correlated any alterations in retinal structure with previously measured alterations in electroretinograms (ERGs). Age-matched rats were fed a basal diet deficient in both vitamin E and selenium (B diet), a basal diet supplemented with vitamin E alone (B+E diet), or selenium alone (B+Se diet), or with both micronutrients (B+E+Se). Half the rats in each group were treated (+HBO) with hyperbaric oxygen (100% O2 at 3 ATA for 1.5 per hr day, 5 days per week) and half were not (-HBO). We previously found that the rats fed the B diet for 6 weeks and treated with HBO for 4 weeks (B+HBO group) had diminished a-wave ERG amplitudes. At this time point all rats in the B group and half of the rats in the B+E+Se group were killed for the structural studies reported here. Surprisingly, we found no evidence of photoreceptor cell necrosis [i.e. a decreased thickness of the outer nuclear layer (ONL)] in retinas from rats in the B+HBO group despite the diminished amplitude of the a-wave which arises from this retinal layer. Quantitative structural analyses of retinas from rats in the B+HBO, B-HBO, B+E+Se-HBO and B+E+Se+HBO groups also failed to reveal any significant differences in the cell height of the retinal pigmented epithelium (nasal, central or temporal regions) or the number of mitochondria, phagosomas or inclusion bodies in the central retinal pigment epithelium (RPE). The inner nuclear layer (INL) thickness was, however, consistently decreased in all retinal regions for the rats in the B+HBO group. Our previous work also showed that only rats fed the B+Se diet for 17 weeks and treated with HBO for 15 weeks (B+Se+HBO group) showed diminished a-wave and b-wave ERG amplitudes. At this time point rats in the B+E+Se, B+E, and B+Se groups were killed for structural studies reported here. Only rats in the B+Se+HBO group showed a significantly decreased (about 20%) thickness of the central ONL. This evidence of photoreceptor cell necrosis correlated very well with our previous observation of diminished a- and b-wave amplitudes only in the B+Se+HBO group (at week 17).(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1992

Transitive inference in rats (Rattus norvegicus).

Although Piagetian theory proposes that the ability to make transitive inferences is confined to humans above age 7, recent evidence has suggested that this logical ability may be more broad based. In nonverbal tests, transitive inference has been demonstrated in preschool children and 2 species of nonhuman primates. In these experiments, I demonstrate evidence of transitive inference in rats (Rattus norvegicus). I used an ordered series of 5 olfactory stimuli (A < B < C < D < E) from which correct inferences were made about the novel B versus D pair. Control procedures indicated that performance did not depend on the recency with which the correct answer was rewarded during training and may be disrupted by the addition of logically inconsistent premises (F > E and A > F). The possibility that logical transitivity may reflect a form of spatial paralogic rather than formal deductions from a syllogistic-verbal system is discussed.

Animals↗
PubMed1992

Hostility: relationship to lifestyle behaviors and physical risk factors.

The relationship between hostility and coronary artery disease may be partially mediated by unhealthy lifestyle behaviors. This study examined the relationship between hostility, lifestyle behaviors, and physical risk factors in 138 adult men and women. Subjects completed the Cook and Medley Hostility Scale (Ho scale) and self-reports of their dietary habits, consumption of alcohol and cigarettes, and physical activity. Recent findings indicated that a composite hostility score from three rationally derived subscales of the Ho scale tapping the dimensions of cynicism, hostile affect, and aggressiveness was a better predictor of mortality than the total Ho score. Thus, this composite measure of hostility and the total Ho score were used in data analyses. Measures of resting blood pressure, height, weight, and adiposity were also obtained. In men and women, both measures of hostility were positively associated with cholesterol intake and vigorous physical activity. Among women, both hostility measures were positively related to animal fat intake and negatively related to fiber intake. The composite measure was positively related to their resting systolic pressures. Among men, both hostility measures were positively related to cigarette smoking and sugar intake and negatively associated with systolic blood pressure and calcium intake. Findings are discussed in terms of previous research linking hostility to lifestyle behaviors and CAD.

Adult↗
PubMed1992

A comparison of the interviewing skills of first- and final-year medical students.

This study compared the communication skills of randomly chosen first- and final-year medical students. The intention was to follow up previous research, conducted over 10 years ago, into the effects of the medical curriculum on communication skills. It was hypothesized that there would be little improvement in such skills over the period of training, with the possibility that the final-year students might be less caring, empathic and supportive, more directive, and less concerned with psychosocial information. All students interviewed a simulated patient in the role of a mother of a child with cerebral palsy, where the main problems were psychological and social. The interviews were recorded on videotape and analysed by an independent observer for the presence or absence of a set of communication behaviours considered important in facilitating an effective relationship and in the exploration and understanding of the problem. The results failed to support the hypotheses. The final-year students were superior to their juniors on several measures, indicating improvements in relating to the patient in a caring, empathic, facilitative and listening manner. They also elicited more information relevant to the problem. The indications were that these final-year students were more skilled than in earlier studies, suggesting that the general change in attitudes to communications skills and the limited, but increased input into the curriculum may be having effect, even though there remains a need for considerably more training.

Attitude↗
PubMed1992

Relationship between the Millon Clinical Multiaxial Inventory and the Millon-II: value of scales for Aggressive and Self-defeating personalities in Posttraumatic Stress Disorder.

This study addressed two issues, the interrelationship between the Millon Clinical Multiaxial Inventory (MCMI) and the Millon II (MCMI-II) and the value of the new personality scales, Aggressive and Self-defeating, in a sample with diagnoses of combat-related Posttraumatic Stress Disorder. 100 confirmed cases of combat-related Posttraumatic Stress Disorder were given a battery of measures including both Millon inventories and the Minnesota Multiphasic Personality Inventory (basic scales and selected subscales). They were rated on discharge status during a structured treatment program. Basic treatment and background information were also obtained. Analysis showed scores on the MCMI-II scales were higher but generally reflective of MCMI scales and that the Self-defeating personality style tends to be reflective of greater psychopathology, suicidal problems, treatment/disposition difficulties, overreporting of symptoms, and intensity of problems. Discussion encouraged the use of the MCMI-II with special emphasis given to the Self-defeating style in this group with Posttraumatic Stress Disorder.

Adult↗
PubMed1992

Improving utilization and patient care. A rural hospital reduces length of stay through policy revisions and education.

In 1990 Saint Vincent Memorial Hospital, Taylorville, IL, intensified efforts to improve resource utilization. A program of daily case review and medical staff education has helped the hospital reduce average length of stay from between 7 and 8 days to between 5 and 6.8 days. Steps taken to achieve this include: Hiring an outside medical adviser to oversee collection and analysis of data related to length of stay and conduct case reviews Appointing a medical review officer and a physician-specific case manager Establishing a Utilization Management Task Force, which has reformed the policy concerning patients with methicillin-resistant Staphylococcus aureus to ensure discharge in a timely manner; implemented a nonacute-day reporting system; and completed a transitional care study to identify the benefits of transferring medically stable Medicare patients to the Skilled Nursing Facility.

Catholicism↗
PubMed1992

An encephalomyocarditis virus epizootic in a baboon colony.

Approximately 80 baboon deaths were caused by encephalomyocarditis virus (EMCV) infection in a 3060 member research and production colony. The epizootic extended over a 9-month period and occurred in baboons ranging from 1 day to 22 years of age. Acute death was the most common history. When clinical disease was detected, it was characterized by labored respiration associated with acute congestive heart failure. The salient necropsy findings were pulmonary congestion and edema, hydropericardium, hydrothorax, ascites, lymph node and splenic hypertrophy, and pale white-to-tan mottled hearts. The most significant histologic lesion was nonsuppurative necrotizing myocarditis. Placental infection with fetal loss occurred. Diagnosis was confirmed by light microscopy, transmission electron microscopy, virus culture, and serology. Rarely, EMCV-induced antibody persisted in surviving baboons for more than 24 months. EMCV-infected feral rats were the probable source of the virus and their control stopped the epizootic. No EMCV neutralizing antibody was detected in colony support personnel or chimpanzees.

Animals↗
PubMed1992

Reliability and variability of heart rate monitoring in 3-, 4-, or 5-yr-old children.

We describe the daily heart rate patterns and the between day and within day reliabilities of several heart rate variables measured in 159 Anglo-, African-, and Mexican-American children aged 3-5 yr. Heart rates were measured over 12 waking hours with a Quantum XL Telemetry heart rate monitor. There were no significant ethnic, gender, day of week, or season of the year differences in either mean resting heart rate, mean daily heart rate, mean longest duration of the heart rate sustained above 120 bpm for the day, nor percent of minutes of daily heart rate above 120 bpm. The reliabilities for these variables for 2 d of observation separated by 3-6 months ranged from 0.65 to 0.66. At this level of reliability, just over 4 d of recording are necessary to achieve a reliability of 0.80. All within-day across-hour reliabilities were greater than 0.80. However, for mean hourly heart rate and the longest duration of heart rate sustained above 120 bpm each hour, a principal components analysis revealed three distinct time components during the day. This suggests that monitoring heart rate during limited portions of the day will provide a biased estimate of overall heart rate. For the morning component, there were significant ethnic and gender differences in the children's heart rates and younger children had longer durations of heart rate sustained above 120 bpm than older children. Although daily heart rate monitoring is not a perfect indicator of children's physical activity, these data suggest that it may be a reliable measure among younger children from different ethnic and gender groups.

Black People↗
PubMed1991

Family history of myocardial infarction and hemodynamic responses to exercise in young black boys.

The influence of family history of coronary artery disease on children's hemodynamic responses to exercise was examined with 25 black boys aged 7 to 10 years. Blood pressure, heart rate, cardiac output, stroke volume, and total peripheral resistance were evaluated during preexercise, peak exercise, and recovery stages. Children with a family history of CAD exhibited greater systolic blood pressure and total peripheral resistance during preexercise and peak exercise stages than did those without a family history of coronary artery disease. After controlling for preexercise differences, the group with a family history of coronary artery disease exhibited greater increases in systolic blood pressure and less attenuation of total peripheral resistance to peak exercise than the group without a family history of coronary artery disease. Cardiac output indexed by body surface area and stroke volumes were higher at all times in the group without a family history compared with the group with a family history of coronary artery disease. Findings are compared with those of adult studies in terms of influence of family history of coronary artery disease on cardiovascular reactivity to stress.

Black People↗
PubMed1991

A short form of the Mississippi Scale for Combat-Related PTSD.

At the present time, The Mississippi Scale for Combat-Related PTSD (Mississippi Scale) is the best paper-and-pencil measure of this disorder. This study carried out a test-retest reliability on 52 chronic Vietnam veterans with PTSD and established three psychometric criteria for item retention in order to establish a short form of the Mississippi Scale. Ten items met these criteria and had a test-retest reliability coefficient of .66 (under the most stringent of conditions, treatment). This 10-item measure (Miss-10) then was applied to 95 new PTSD cases. This scale yielded two factors, guilt and numbing/anger. Discussion addressed its use as part of a screening battery or for monitoring change across time.

Adult↗
PubMed1991

Effects of acyl-CoA: cholesterol O-acyltransferase inhibition on cholesterol absorption and plasma lipoprotein composition in hamsters.

1. The ACAT inhibitors, CL 277082 and SA 58-035 were administered for 7 days to hamsters fed diets containing 0.5% cholesterol. 2. Both agents inhibited cholesterol absorption, decreased hepatic. VLDL and IDL cholesterol esters, plasma HDL and HDL apoE and A-I. 3. In addition, CL 277082 treatment produced significant decreases in plasma cholesterol, VLDL apoB and plasma IDL. 4. The cholesteryl esters in VLDL and LDL but not HDL were more polyunsaturated in CL 277082 treated animals. 5. These results support the hypothesis that ACAT inhibition in the cholesterol fed hamster results in an inhibition of dietary cholesterol absorption, thus limiting the cholesterol supply required for the hepatic production of triglyceride-rich lipoproteins.

Absorption↗
PubMed1991

Hidden PTSD in substance abuse inpatients among Vietnam veterans.

Alcohol use patterns among Vietnam combat veterans is an area with little research. This study evaluated three groups of Vietnam subjects on a chemical dependency unit who had a current Axis I diagnosis of alcohol abuse. No subject possessed a PTSD diagnosis. Two groups involved in-country veterans divided by presence or absence of PTSD based on the MMPI-PTSD scale (In-country and PTSD). The third group did not experience combat and was below the mean on the MMPI-PTSD scale (Noncombat). These groups were compared on the MMPI and the Alcohol Use Inventory (AUI), a measure of alcohol use patterns. Results showed that the PTSD Group had significantly higher scores on the MMPI and AUI reflective of deteriorated and binge drinking patterns. Discussion focused on the "hidden" dimension of PTSD among chemically dependent Vietnam veteran inpatients. The Relapse Prevention model was endorsed.

Alcohol Drinking↗
PubMed1991

A prospective analysis of intramuscular meperidine, promethazine, and chlorpromazine in pediatric emergency department patients.

STUDY OBJECTIVE: To examine physiologic responses and efficacy of 2, 1, and 1 mg/kg IM meperidine, promethazine, and chlorpromazine (MPC), respectively, in children. DESIGN: Prospective, unblinded trial. SETTING: A university and community emergency department. PATIENTS: Sixty-three hemodynamically and neurologically stable children. INTERVENTION: Single dose of IM MPC. MEASUREMENTS AND MAIN RESULTS: Serial respirations, heart rate, arterial systolic blood pressure, oxygen saturation, and Glasgow Coma Scale were measured at 30-minute intervals. Effectiveness was assessed by two independent observers using separate visual analog scales for cooperation and sedation. Times to sleep (27 +/- 24 minutes), sitting upright (103 +/- 87 minutes), ED discharge (4.7 +/- 2.4 hours), eating (11 +/- 7.9 hours), and normal behavior (19 +/- 15 hours) were acceptable. Minor, but statistically significant, changes in respiration rate (-1.9 +/- 0.4), heart rate (+4.5 +/- 1.8), oxygen saturation (-0.7 +/- 0.3%), and Glasgow Coma Scale (-2.5 +/- 0.6) occurred for 120 minutes after MPC. No serious complications or resuscitation were required. Mean visual analog scale scores were 5.0/10.4 or more in 71% of cases, with interobserver agreement very good (cooperation, r = .79; effectiveness, r = .80). Twenty-nine percent of children were judged insufficiently sedated. CONCLUSION: IM MPC is a safe and generally effective agent for ED procedures in selected children.

Anesthesia↗