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Biomedical subjects

K Dunn

Publications and source records attributed to K Dunn.

At least 55 records · Page 3Linked to original sources
PubMed1996

In normal postmenopausal women physiologic estrogen replacement therapy fails to improve exercise tolerance: a randomized, double-blind, placebo-controlled, crossover trial.

OBJECTIVE: Our purpose was to test whether estrogen replacement therapy could increase exercise tolerance in postmenopausal women. STUDY DESIGN: A randomized, double-blind, placebo-controlled, crossover study in 31 healthy postmenopausal women who received 12 weeks of physiologic estrogen replacement therapy (micronized estradiol, 2 mg/day) and were evaluated with modified Balke exercise treadmill tests. RESULTS: Serum estradiol levels increased significantly during replacement therapy in this cohort of female volunteers with a mean age of 59 years, and resting heart rate was lower in women receiving estrogen replacement (p < 0.05). However, neither the heart rate nor the blood pressure responses to exercise was different, nor was the total exercise time, rate of oxygen uptake, or maximal oxygen uptake increased after estradiol treatment. Similarly, ventilatory parameters were unaffected by estradiol. The slope of the respiratory exchange ratio was slightly but significantly different (p < 0.05) while volunteers received estrogen replacement therapy. CONCLUSION: Estrogen replacement therapy, which achieves serum estradiol concentrations in the physiologic range for 12 weeks, fails to increase exercise tolerance or improve cardiovascular response to exercise in postmenopausal women.

Cross-Over Studies↗
PubMed1996

Sex and sexuality.

Midwives' clinical focus on contraception may not be the only way of meeting women's needs after childbirth. When a woman does not return to full sexual function, the explanations available to her tend to emphasise natural/biological, physical and psychological factors. These explanations may fall short of describing the experiences of many women. Midwives need to facilitate opportunities for women to raise issues and concerns significant to them so that women may explore changes in their experience of their own sexuality. To help women to anticipate changes in their lives after childbirth more fully, midwives need to facilitate discussion of sexuality--not just sexual activity--during antenatal preparation and postnatally.

Female↗
PubMed1995

Symbiotic induction of a MADS-box gene during development of alfalfa root nodules.

In response to infection by Rhizobium, highly differentiated organs called nodules form on legume roots. Within these organs, the symbiotic association between the host plant and bacteria is established. A putative plant transcription factor, NMH7, has been identified in alfalfa root nodules. nmh7 contains a MADS-box DNA-binding region and shows homology to flower homeotic genes. This gene is a member of a multigene family in alfalfa and was identified on the basis of nucleic acid homology to plant regulatory protein genes (MADS-box-containing genes) from Antirrhinum and Arabidopsis. RNA analysis and in situ hybridization showed that expression of this class of regulatory genes is limited to the infected cells of alfalfa root nodules and is likely to be involved in the signal transduction pathway initiated by the bacterial symbiont, Rhizobium meliloti. The expression of nmh7 in a root-derived organ is unusual for this class of regulatory genes.

Amino Acid Sequence↗
PubMed1995

Decay in quality of closed-chest compressions over time.

STUDY OBJECTIVE: To characterize fatigue-induced deterioration in the adequacy of closed-chest compressions performed over a period of 5 minutes and to determine whether CPR providers can recognize the effects of fatigue on compression adequacy. DESIGN: Prospective evaluation of study subjects performing closed-chest compressions on an electronic mannequin that assesses compression placement and depth. SETTING: Major resuscitation room in rural university hospital emergency department. PARTICIPANTS: Eleven experienced nursing assistants who regularly provide CPR in the ED. RESULTS: Each study participant performed 5 minutes of closed-chest compressions. Compression adequacy (for placement and depth) was assessed with the mannequin and reported on an attached monitor out of view of the study subjects. Subjects were asked to verbally indicate the point during their 5-minute compression period at which they felt too fatigued to provide effective compressions (arbitrarily defined as a minimum of 90% of all compressions being judged correct by the mannequin). We used one-way repeated-measures ANOVA and regression analysis to determine whether compression adequacy diminished over time. ANOVA was also used to determine whether the total compressions performed per minute diminished over time. The percentage of correct chest compressions decreased significantly after 1 minute of compressions (P = .0001). We found 92.9% of compressions performed during minute 1 to be correct. The percentages for minutes 2 through 5 were as follows: 67.1%, 39.2%, 31.2%, and 18.0%. Regression analysis revealed a decrement in compression adequacy of 18.6% per minute after the first minute of compressions. The number of total compressions attempted per minute did not decrease (P = .98). Study subjects did not accurately identify the point during their 5-minute sessions at which their fatigue caused compressions to become impaired. Whereas mean compression adequacy declined below 90% after only 1 minute, the time of indicated fatigue was 253 +/- 40 seconds (mean +/- SD). CONCLUSION: Although compression rate was maintained over time, chest compression quality declined significantly over the study period. Because CPR providers could not recognize their inability to provide proper compressions, cardiac arrest team leaders should carefully monitor compression adequacy during CPR to assure maximally effective care for patients receiving CPR.

Analysis of Variance↗
PubMed1995

Lens epithelial cell apoptosis appears to be a common cellular basis for non-congenital cataract development in humans and animals.

Cataract is a major ocular disease that causes blindness in many developing countries of the world. It is well established that various factors such as oxidative stress, UV, and other toxic agents can induce both in vivo and in vitro cataract formation. However, a common cellular basis for this induction has not been previously recognized. The present study of lens epithelial cell viability suggests such a general mechanism. When lens epithelial cells from a group of 20 cataract patients 12 to 94 years old were analyzed by terminal deoxynucleotidyl transferase (TdT) labeling and DNA fragmentation assays, it was found that all of these patients had apoptotic epithelial cells ranging from 4.4 to 41.8%. By contrast, in eight normal human lenses of comparable age, very few apoptotic epithelial cells were observed. We suggest that cataract patients may have deficient defense systems against factors such as oxidative stress and UV at the onset of the disease. Such stress can trigger lens epithelial cell apoptosis that then may initiate cataract development. To test this hypothesis, it is also demonstrated here that hydrogen peroxide at concentrations previously found in some cataract patients induces both lens epithelial cell apoptosis and cortical opacity. Moreover, the temporal and spatial distribution of induced apoptotic lens epithelial cells precedes development of lens opacification. These results suggest that lens epithelial cell apoptosis may be a common cellular basis for initiation of noncongenital cataract formation.

Adult↗
PubMed1995

Massive fungal contamination in animal care facilities traced to bedding supply.

During the course of immunologic studies involving the gastrointestinal colonization of mice with Candida albicans, it became apparent that the animals were being exposed to large numbers of Aspergillus fumigatus spores which interfered with the C. albicans colonization. To determine the source of the A. fumigatus exposure and the extent of fungal contamination of the medical school vivarium and four satellite facilities, fungal analyses of feed, bedding, and air were undertaken. Initial samples from the air were collected with 3-h settle plates; air sampling following cleanup was done with an Anderson air sampler. The source of contamination in the mouse rooms was determined to be Beta Chip bedding, which came from the manufacturer highly contaminated. Beta Chip bedding (1 g) obtained from the manufacturer just prior to testing contained 10(4) CFU of A. fumigatus, 20 CFU of a zygomycete, and 10 CFU of a Penicillium sp. Coarse-grade Beta Chip had approximately one-half those levels of contamination. Pure Cob bedding was highly contaminated also, but with a Fusarium sp. and a Cladosporium sp. Untreated and heat-treated Sani-Chip as well as all other heat-treated preparations obtained from the manufacturer contained no detectable spores. Rodent chow direct from the manufacturer had no A. fumigatus, although it did contain 150 CFU of fungus per g, including 80 CFU of a Rhodotorula sp., 60 CFU of Cryptococcus uniguttulatus, and 1 CFU of a Penicillium sp.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

Determining educational needs for the biomedical library customer: an analysis of end-user searching in MEDLINE.

The analysis of CD Plus usage logs provides an opportunity to determine specific areas where searchers are "missing opportunities" by misusing, or failing to use, system specific features. This paper describes a methodology, based on transaction log analysis, to provide automated, continuous analysis of end-user searching. The data collected in this process can then be used to enhance and provide insight into the educational needs of users.

CD-ROM↗
PubMed1995

A quantitative method for measuring clinical user journal needs: a pilot study using CD Plus MEDLINE usage statistics.

OBJECTIVE: To develop a quantitative method for measuring clinical user journal needs based on an analysis of bibliographic search results. DESIGN: Retrospective bibliometric comparison of citation selections generated by clinical users on shared workstations throughout the Medical Center. MEASURES: Number of times each journal was identified by clinical users during multiple bibliographic search sessions. RESULTS: Clinical users identified 2,078 journal articles. The top 200 journal titles accounted for 55% of the clinical users' journal needs. Of the 901 unique journal titles identified, 489 (54%) were identified only once. CONCLUSION: Our pilot study demonstrates that analysis of bibliographic search results can be used to identify clinical user journal needs. Such a method could also be used to estimate user requirements for on-line, full-text medical journals.

CD-ROM↗
PubMed1994

A quantitative method for measuring library user journal needs: a pilot study using CD plus MEDLINE usage statistics.

OBJECTIVE: To develop a quantitative method for measuring library user journal needs based on an analysis of bibliographic search results. DESIGN: Retrospective bibliometric comparison of citation selections generated by users in the library. MEASURES: Number of times each journal was identified by library users during multiple bibliographic search sessions. RESULTS: Library users identified 4907 journal titles. The top 200 journal titles accounted for 55% of the library user journal needs. Of the 1380 unique titles identified, 652 were selected once. CONCLUSION: Our pilot study demonstrated that analysis of bibliographic search results can be used to identify library user journal needs. Such a method could also be used to estimate user requirements for online, full-text scientific journals.

Bibliometrics↗