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Biomedical subjects

J R Morrow

Publications and source records attributed to J R Morrow.

At least 19 recordsLinked to original sources
PubMed1994

Artificial ribonucleases.

Many inorganic and organic compounds promote the reactions catalyzed by RNase A. Both the transesterification step, where a 2',3'-cyclic phosphate is formed with concomitant cleavage of RNA, and the hydrolysis step, where the 2',3'-cyclic phosphate is converted to a phosphate monoester, may be mimicked with compounds that are readily synthesized in the laboratory. Electrophilic activation of the phosphate ester and charge neutralization are generally important means by which artificial RNases promote phosphate diester displacement reactions. Several artificial RNases operate by a bifunctional general acid/general base mechanism, as does RNase A. Provision of an intramolecular nucleophile appears to be an important pathway for metal complex promoted phosphate diester hydrolysis. In contrast to the successful design of compounds that promote the reactions catalyzed by RNase A, there are no artificial nucleases to date that will cleave the 3' P-O bond of RNA or hydrolyze an oligonucleotide of DNA. Artificial RNases based on both metal complexes and organic compounds have been described. Metal complexes may be particularly effective catalysts for both transesterification and hydrolysis reactions of phosphate diesters. Under physiological conditions (37 degrees C and neutral pH), several metal complexes catalyze the transesterification of RNA. Future work should involve the development of metal complexes which are inert to metal ion release but which maintain open coordination sites for catalytic activity. The design of compounds containing multiple amine or imidazole groups that may demonstrate bifunctional catalysis is a promising route to new artificial RNases. Further design of these compounds and careful placement of catalytic groups may yield new RNase mimics that operate under physiological conditions. The attachment of artificial RNases to recognition agents such as oligodeoxynucleotides to create new sequence-specific endoribonucleases is an exciting field of endeavor. Applications for such sequence-specific endoribonucleases include in vitro manipulations of RNA and the destruction of gene transcripts in vivo. Further work will require the development of new synthetic methodologies for attachment of catalytic cleaving groups to oligodeoxynucleotides.

Base Sequence↗
PubMed1994

Caltrac versus calorimeter determination of 24-h energy expenditure in female children and adolescents.

The purpose of this study was to determine the validity of the Caltrac accelerometer for estimating 24-h energy expenditure (EE) in children and adolescents. EE for 40 girls (13.0 +/- 1.8 yr) was assessed for 24 h via indirect calorimetry in whole-room calorimeters. EE and activity level were estimated concurrently by two Caltrac accelerometers placed on the subjects at each hip. Significant correlations (P < 0.001) resulted between Caltrac estimates and calorimeter values for 24-h total EE (TEE, r = 0.80), sedentary daily EE (SDEE, r = 0.84), and waking EE (WEE, r = 0.85). Nonetheless, the Caltrac significantly (P < 0.001) underestimated EE in all experimental conditions (TEE: -13.3 +/- 8.6%; SDEE: -6.8 +/- 7.3%; WEE: -30.4 +/- 8.5%). A significant multiple correlation between calorimeter values and a combination of Caltrac activity counts and body weight (R = 0.86, P < 0.001) suggested these variables could be useful for daily EE estimation. Additional analyses indicated that as EE increased, the absolute difference between Caltrac and calorimeter values also increased. The significant correlations between Caltrac and calorimeter values suggest the Caltrac may be useful for assessing daily caloric expenditure for groups of children.

Acceleration↗
PubMed1992

Quality of life of hospitalized persons with AIDS.

This study explores quality of life from the viewpoint of Persons with AIDS (PWAs) who were interviewed during periods of hospitalization. Quality of life was viewed as the patients' perception of the relative effectiveness of a chosen or ascribed management style in solving the practical problems associated with being ill. Six management styles used by the respondents to improve their quality of life were identified. Results of this study suggest that nurses can improve PWAs' quality of life by supporting their respective management styles.

Acquired Immunodeficiency Syndrome↗
PubMed1992

Menstrual cycle phase affects temperature regulation during endurance exercise.

We investigated whether menstrual cycle phase would affect temperature regulation during an endurance exercise bout performed at room temperature (Ta) of 22 degrees C and 60% relative humidity. Nine eumenorrheic women [age 27.2 +/- 3.7 yr, peak O2 uptake (VO2) 2.52 +/- 0.35 l/min] performed 60 min of cycle exercise at 65% of peak VO2. Subjects were tested in both midfollicular (F) and midluteal (L) phases, although one woman did not show a rise in serum progesterone (P4) that is typically evident 1 wk after ovulation. VO2, rectal (Tre) and skin (Tsk) temperatures, heart rates (HR), and ratings of perceived exertion (RPE) were measured throughout exercise. Sweat loss (SL) was estimated from pre- and postexercise body weight differences. VO2, SL, and Tsk were not affected by menstrual cycle phase. Preexercise Tre was 0.3 degrees C higher during L than during F conditions, and this difference increased to 0.6 degrees C by the end of exercise (P less than 0.01). Compared with F, HRs during L were approximately 10 beats/min greater (P less than 0.001) at all times, whereas RPE responses were significantly greater (P less than 0.01) by 50 min of cycling. No differences in any measured values were found in the subject whose P4 was low in both test conditions. Results indicate that thermoregulation (specifically, regulation of Tre), as well as cardiovascular strain and perception of exercise, was adversely affected during the L phase.

Adult↗
PubMed1989

Development of valid pulmonary function equations for trained athletes.

The validity of commonly recommended pulmonary function prediction equations (Bulletin Européen de Physiopathologie Respiratoire, Clinical Respiratory Physiology) was tested with two samples (n1 = 156; n2 = 218) of well-trained athletes. Pulmonary function measures (FVC, TLC, RV, FEF25%-75%, FEV1.0, PEF, RV/TCL ratio, FEV1.0/FVC ratio) were typically very reliable but inaccurately predicted with recommended equations based upon anthropometric characteristics. Newly developed "unisex" regression equations were developed with "dummy" coding of gender (i.e., 0 = female; 1 = male), age, height, weight, and various interactions. The new equations were validated with a subsample of group one, cross-validated with the remaining portion of group one, and then cross-validated again with the 218 subjects from sample two. The newly created pulmonary function prediction equations are more valid for well-trained athletes than the equations in use for the general population.

Adult↗
PubMed1987

Learner characteristics associated with responses to film and interactive video lessons on smokeless tobacco.

To determine college students' cognitive and affective responses to alternative technologies for presenting a lesson on smokeless tobacco, and to learn if responses to experimental conditions were associated with gender, ethnicity, tobacco-use practices, and the practices of significant others, 162 undergraduate students were randomly assigned to either a control group (questionnaire only) or one of two experimental groups. Experimental subjects viewed a videotape or an interactive video version of the lesson and then completed a questionnaire to ascertain knowledge and attitude. Each main effect was significant for knowledge about smokeless tobacco [experimental condition (P less than 0.001); gender (P less than 0.024); and ethnicity (P less than 0.003)]. The interactive video group demonstrated the most accurate and comprehensive recall. Neither gender nor ethnicity interacted significantly with experimental condition, indicating that the effect of experimental condition is constant across gender and ethnicity. Attitudes to instructional formats did not vary significantly as a function of experimental condition or gender, but were associated with ethnicity (P less than 0.034). Again, neither gender nor ethnicity interacted significantly with experimental condition, suggesting that attitudes reflect a generalized view toward content irrespective of presentation mode. Responses to both experimental conditions were quite favorable. Items about present and past experiences with tobacco, with the exception of the "Do you smoke?" item, were not associated with total cognitive score or attitude.

Attitude to Health↗
PubMed1987

Disparities in adolescent-physician views of teen health information concerns.

To enhance communications between physicians and adolescents, 600 middle school students and 99 physicians completed written questionnaires assessing the importance of 45 items from seven subscales: smoking; physical fitness; weight control; self-actualization; comparison with others; peer opinion; and communications. Adolescents rated the importance of knowing about items from each scale. Physicians rated how much importance they attached to each scale and their perception of the adolescents' ratings. Physicians placed more importance on each scale than did the adolescents, and they did not accurately judge the importance adolescents placed on the items. Physicians and adolescents differed significantly in the ratings of all but one scale, weight. With the exception of one scale (peer opinion), physicians estimated that adolescents would place less importance on the items in each scale than the adolescents actually reported. Our results suggest the need to concurrently consider adolescent-physician views when seeking to meet adolescents' health needs.

Adolescent↗
PubMed1986

A comparison of physician-patient views of teen prenatal information needs.

To help physicians provide supportive information to pregnant teens, 146 pregnant adolescents and 46 physicians completed self-administered questionnaires about prenatal and infant care. Teens placed great importance on knowing about prenatal and parenting behaviors. Teens and physicians generally attached similar importance to concerns across all items (p less than 0.45). Both groups considered similar items extremely important, with the exception of birth control, which was more frequently rated extremely important by physicians (p less than 0.001). However, physicians reported differences between the importance they attached and the importance they thought teens would attack to items (p less than 0.001). Physicians did not accurately estimate the importance teens would attribute to 23 of the 24 items (p less than 0.001), and they anticipated that the teens would attach significantly less importance to items than the teens actually attached. Psychosocial concerns, which physicians anticipated would be considered most important, were often minimized by teens. Responses were not significantly associated with physician age, sex, or level of training, thus suggesting the need to address patient information concerns at all levels of professional education.

Adolescent↗
PubMed1986

Accuracy of measured and predicted residual lung volume on body density measurement.

The effects of measured and predicted residual lung volume on the accuracy of body density and percent fat (%Fat) were investigated. Adult fitness subjects (N = 46) had residual lung volume measured with the oxygen dilution method while those from an athlete sample (N = 134) utilized the nitrogen washout technique. Residual lung volume was also predicted with gender-specific regression equations using height and age and from 24% of vital capacity (%FVC). Residual lung volume alpha reliability for the average of four residual lung volume trials exceeded 0.90 (SEM less than = 161 ml) for the oxygen dilution method and 0.99 (SEM = 30 ml) for the average of two nitrogen washout measures. The standard errors for predicted residual lung volume were 579 and 355 ml, respectively, for the men and women in the adult sample and 288 ml for the trained athlete sample. Estimating residual lung volume from %FVC yielded a SEE of 318 ml for the trained athlete sample. Measured residual lung volume errors resulted in errors of 1.04%Fat, 0.87%Fat, and 0.21%Fat for the men, women, and trained athlete samples, respectively. In contrast, predicted residual lung volume measurement errors resulted in errors of 3.70%Fat, 2.85%Fat, and 1.98%Fat for the respective samples and 2.18%Fat when using %FVC with the trained athletes. Measured residual lung volume introduces little %Fat error while predicted residual lung volume introduces a substantial source of measurement error.

Adipose Tissue↗
PubMed1984

Attitudes toward health and illness. A comparison of adolescent, physician, teacher, and school nurse views.

To assist physicians, teachers, and school nurses in meeting adolescent health needs, 240 members of these three professional groups and 600 middle school students answered a self-administered questionnaire to assess student attitudes towards health and illness. chi 2 Analyses were employed to determine if response patterns varied as a function of the group. Incongruencies (p less than 0.05) were noted between students' and professionals' responses to all questions. Adolescents attributed more importance to their health, showed a better personal health status, expressed more worry about personal health and becoming sick and more concern about being sick, showed more feelings of responsibility for their health, and exhibited less frequent practice of harmful behaviors than adults anticipated that the students would report. Adults differed in their perceptions of the students' reported health status and the frequency of student worry about personal health and being sick. Findings are discussed in relation to the provision of more meaningful, comprehensive, multidisciplinary approaches to meeting adolescent health care needs and concerns.

Adolescent↗