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Biomedical subjects

M R Rose

Publications and source records attributed to M R Rose.

At least 37 records · Page 2Linked to original sources
PubMed1998

Opening the black box: how do physicians communicate about advance directives?

BACKGROUND: The quality of communication that leads to the completion of written advance directives may influence the usefulness of these documents, but the nature of that communication remains relatively unexplored. OBJECTIVE: To describe how physicians discuss advance directives with patients. DESIGN: Prospective study. SETTING: Five outpatient primary care medicine practices in Durham, North Carolina, and Pittsburgh, Pennsylvania. PARTICIPANTS: 56 attending internists and 56 of their established patients. Eligible patients were at least 65 years of age or had a serious medical illness. MEASUREMENTS: Two raters coded transcripts of audiotaped discussions about advance directives to document how physicians introduced the topic of advance directives, discussed scenarios and treatments, provided information, elicited patient values, and identified surrogate decision makers. RESULTS: Conversations about advance directives averaged 5.6 minutes; physicians spoke for two thirds of this time. In 91% of cases, physicians discussed dire scenarios in which most patients would not want to be treated, and 48% asked patients about their preferences in reversible scenarios. Fifty-five percent of physicians discussed scenarios involving uncertainty, typically using vague language. Patients' values were rarely explored in detail. In 88% of cases, physicians discussed surrogate decision making and documents to aid in advance care planning. CONCLUSIONS: Although they accomplished the goal of introducing patients to advance directives, discussions infrequently dealt with patients' values and attitudes toward uncertainty. Physicians may not have addressed the topic in a way that would be of substantial use in future decision making, and these discussions did not meet the standards proposed in the literature.

Adult↗
PubMed1998

The effect of diclofenac (voltarol) and pethidine on ureteric peristalsis and the isotope renogram.

Diclofenac (a non-steroidal anti-inflammatory drug) and pethidine (a synthetic opiate) are the two analgesics most commonly used to relieve the pain of ureteric colic. Fast frame renography is a non-invasive means of imaging ureteric peristalsis and renal drainage. The aim of this study was to determine the effects of each of these drugs on the drainage pattern of the upper tracts. Twelve normal male volunteers were studied. All underwent a standard fast frame renogram using 75 MBq of technetium-99m-mercaptoacetyltriglycine, and were then administered either 100 mg pethidine or 75 mg diclofenac by intramuscular injection. Fast frame renography was then repeated. Peristalsis was determined from the condensed image of each ureter and the renogram curves were analysed to obtain standard parameters and deconvolution analysis. Diclofenac caused a profound disruption to both ureteric peristalsis and the renogram curve. This effect was not seen after the administration of pethidine. Deconvolution analysis suggests the effects of diclofenac are mediated via a direct effect on drainage rather than by any alteration of blood flow to the kidney. This study suggests that pethidine is the analgesic of choice prior to renography and that inferences about alterations of drainage in the presence of diclofenac should be interpreted with care.

Adult↗
PubMed1998

Patient knowledge and physician predictions of treatment preferences after discussion of advance directives.

OBJECTIVE: To determine patient knowledge about life-sustaining treatments and physician understanding of patient preferences for proxies and treatments after outpatient discussions about advance directives. DESIGN: Cross-sectional interview-based and questionnaire-based survey. SETTING: Two university general internal medicine practices, two Department of Veterans Affairs general internal medicine practices, and one university-based geriatrics practice, in two different cities. PATIENTS: Fifty-six patients of primary care internists. INTERVENTION: Physicians discussed "advance directives" (ADs) with one randomly selected patient during an outpatient visit. MEASUREMENTS AND MAIN RESULTS: After the discussions, physicians identified the patient's proxy and predicted the patient's preferences for treatment in 20 scenarios. Patients provided treatment preferences in the 20 scenarios, the name of their preferred surrogate decision maker, and their understanding of cardiopulmonary resuscitation and mechanical ventilation. Of the 39 patients who discussed resuscitation, 43% were able to identify two important characteristics; 26% identified none; 66% did not know that most patients need mechanical ventilation after undergoing resuscitation. None of the 43 patients who had a discussion about mechanical ventilation had a good understanding of it; 67% did not know that patients generally cannot talk while on ventilators; 46% expressed serious misconceptions about ventilators. There was poor agreement between physicians and their patients regarding treatment preferences in 18 of 20 scenarios (kappa -0.04 to 0.31). Physicians correctly identified the proxy 89% of the time (kappa 0.78). CONCLUSIONS: Patients leave routine AD discussions with serious misconceptions about life-sustaining treatments. Physicians are unable to predict treatment preferences but do learn about patients' preferences for surrogate decision makers.

Advance Directives↗
PubMed1998

Using laboratory selection for desiccation resistance to examine the relationship between respiratory pattern and water loss in insects.

We conducted concurrent measurements of rates of CO2 and H2O release from individual fruit flies Drosophila melanogaster taken from populations subjected to three different selective regimes: (1) populations selected for resistance to desiccation (D flies); (2) populations maintained as their controls (C flies); and (3) the ancestral populations of the D and C populations (O flies). In the D flies, water loss rates were significantly reduced, the standard error of the regression (SER) of the CO2 release pattern measured over the survival period of the flies was increased, and the ratio of CO2 loss to H2O loss (VCO2/VH2O) was increased. Correlations across all 15 populations from the three selection treatments indicate that survival time was negatively correlated with water loss rate, positively correlated with the SER of CO2 release and positively correlated with the VCO2/VH2O ratio. We did not, however, find a significant correlation between the SER of CO2 release and rates of water loss or the VCO2/VH2O ratio.

Adaptation, Physiological↗
PubMed1997

A rapidly progressive adolescent-onset oculopharyngeal somatic syndrome with rimmed vacuoles in two siblings.

We describe 2 Greek siblings who developed a rapidly progressive oculopharyngeal somatic syndrome, at the ages of 11 and 14 years, with muscle biopsies showing rimmed vacuoles and, in 1 case, cytoplasmic and intranuclear tubulofilamentous inclusions 25 nm in diameter. Although a similar pattern of muscle involvement with rimmed vacuoles is described in autosomal dominant oculopharyngeal muscular dystrophy, the age of onset, the rapid progression of the symptoms, and the nature of the tubulofilaments distinguish this as a separate entity.

Adolescent↗
PubMed1997

Physiological mechanisms of evolved desiccation resistance in Drosophila melanogaster.

We investigated physiological characters associated with water balance in laboratory populations of Drosophila melanogaster selected for resistance to desiccating conditions for over 100 generations. Five replicate, outbred, desiccation-selected (D) populations were compared with their control (C) populations. Water loss rates of female D flies were approximately 40% lower than those of C females. Although excretory water loss was reduced in desiccation-selected flies, it comprised less than 10% of total water loss, indicating that the D populations have evolved reduced cuticular and/or respiratory water loss rates. Total surface lipid amounts did not differ between the C and D flies. Cuticular hydrocarbons from D flies were longer than those from C flies and melted at slightly higher temperatures, possibly contributing to reduced water loss rates. Desiccation-selected flies contained approximately 30% more bulk water than controls, as well as more glycogen. However, total metabolic water stores did not differ between the stocks owing to higher lipid levels in the C populations. The ability to tolerate water loss, as measured by water content at the time of death, did not differ between D and C flies. Thus, evolution of increased desiccation resistance has occurred by multiple physiological mechanisms, but some potential adaptive differences have not evolved.

Animals↗
PubMed1997

CO2 release patterns in Drosophila melanogaster: the effect of selection for desiccation resistance.

We used laboratory natural selection on insects as a means of investigating the role of patterns of gas exchange in desiccation resistance. We used 15 populations of Drosophila melanogaster: five selected for desiccation resistance, five control populations and five ancestral populations. Using flow-through respirometry, we found that D. melanogaster from all populations produced irregular peaks of CO2 release. To quantify the height and frequency of these peaks, we used the standard error of a linear regression (SER) through the recordings of CO2 release. The values for the SER were significantly larger in the populations selected for desiccation resistance than in the control and ancestral populations. Occasionally, highly periodic peaks of CO2 release were observed in the desiccation-resistant populations only. Maximum SER was found to be strongly correlated with survival time in dry air among selection treatments, but not among individuals within a population. Access to dietary water resulted in lower SER values. These data demonstrate that gas exchange is physiologically controlled in Drosophila melanogaster and that the pattern of gas exchange can change under selection. The relationship between these CO2 release patterns and classic discontinuous ventilation is discussed.

Animals↗
PubMed1996

Evolutionary theory predicts late-life mortality plateaus.

Most demographic data indicate a roughly exponential increase in adult mortality with age, a phenomenon that has been explained in terms of a decline in the force of natural selection acting on age-specific mortality. Scattered demographic findings suggest the existence of a late-life mortality plateau in both humans and dipteran insects, seemingly at odds with both prior data and evolutionary theory. Extensions to the evolutionary theory of aging are developed which indicate that such late-life mortality plateaus are to be expected when enough late-life data are collected. This expanded theory predicts late-life mortality plateaus, with both antagonistic pleiotropy and mutation accumulation as driving population genetic mechanisms.

Adult↗
PubMed1996

Genetic analysis of mechanisms of aging.

A wide range of genetic models with postponed aging are now available, from selected mice and Drosophilia to mutant Caenorhabditis elegans and Saccharomyces cerevisiae. These systems allow efficient testing of alternative mechanistic hypotheses for aging. Genetic analysis is forging stronger connections between particular alleles and susceptibility to particular 'diseases of aging'; for example, two different genes for Alzheimer disease have been identified.

Aging↗
PubMed1996

Sustained myoglobinuria: the presenting manifestation of dermatomyositis.

We describe two patients with sustained myoglobinuria that did not resolve with supportive treatment. After we established a diagnosis of dermatomyositis and started treatment with corticosteroids, there was rapid resolution of the myoglobinuria. Well-documented cases of inflammatory myopathy causing myoglobinuria are rare, but their prompt recognition has important therapeutic implications.

Adult↗
PubMed1995

Hormones and the physiological architecture of life history evolution.

Hormones play key roles in the regulation of animal and plant life histories, particularly in the timing of transitions between prematurational stages and in the scheduling of reproduction. Furthermore, hormonal mechanisms are subject to information about the external and internal environment of the individual. Within an evolutionary radiation, the same hormone subsets often regulate the schedules of development as well as adult reproduction and related activities and, moreover, are involved in mechanisms of senescence. We propose that the pleiotropic and epistatic effects from hormonal and neural mechanisms are an important substratum for life history evolution. This analysis of hormonal mechanisms in senescence implicates a role for antagonistic pleiotropy in selection for particular subsets of hormonal mechanisms that can be traced throughout prematurational and postmaturational stages. In the example of the vertebrate MHC (major histocompatibility complex), polymorphic loci have been assembled with pleiotropic actions on several regulatory axes affecting reproduction and other fitness components. We argue that the MHC and other complex loci may be considered as life history gene complexes, with pleiotropic influences throughout the lifespan. While analyses of this kind might suggest that life histories could be evolutionarily rigid, in our interpretation the population genetics that is involved provides a theoretical basis for great flexibility in hormonal regulation during life history evolution. It is possible that life history evolution among taxonomic groups may sometimes be chaotic, which would frustrate strong inferences by the comparative method in the study of life histories between taxonomic groups.

Animals↗