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Biomedical subjects

C L Marshall

Publications and source records attributed to C L Marshall.

At least 19 recordsLinked to original sources
PubMed2001

A molecular model for the evolution of endothermy in the theropod-bird lineage.

Ectothermy is a primitive state; therefore, a shared common ancestor of crocodiles, dinosaurs, and birds was at some point ectothermic. Birds, the extant descendants of the dinosaurs, are endothermic. Neither the metabolic transition within this lineage nor the place the dinosaurs held along the ectothermic-endothermic continuum is defined. This paper presents a conceptual model for the evolution of endothermy in the theropod-bird lineage. It is recognized that other animals (some fish, insects, etc.) are functionally endothermic. However, endothermy in other clades is beyond the scope of this paper, and we address the onset of endothermy in only the theropod/bird clade. The model begins with simple changes in a single gene of a common ancestor, and it includes a series of concomitant physiological and morphological changes, beginning perhaps as early as the first archosaurian common ancestor of dinosaurs and crocodiles. These changes continued to accumulate within the theropod-avian lineage, were maintained and refined through selective forces, and culminated in extant birds. Metabolic convergence or homoplasy is evident in the inherent differences between the endothermy of mammals and the endothermy of extant birds. The strength and usefulness of this model lie in the phylogenetic, genetic, evolutionary, and adaptive plausibility of each of the suggested developmental steps toward endothermy. The model, although conceptual in nature, relies on an extensive knowledge base developed by numerous workers in each of these areas. In addition, the model integrates known genetic, metabolic, and developmental aspects of extant taxa that phylogenetically bracket theropod dinosaurs for comparison with information derived from the fossil record of related extinct taxa.

Adaptation, Physiological↗
PubMed1998

Infectious mononucleosis and bilateral peritonsillar abscesses resulting in airway obstruction.

Upper airway obstruction is an uncommon but recognized complication of infectious mononucleosis. The management depends upon the degree of airway compromise. In the case described, severe airway obstruction was treated by securing the airway with awake fibre-optic endoscopic intubation and then proceeding to tonsillectomy. Bilateral inferiorly loculated quinsies were encountered unexpectedly and drained. This is the first report of 'bilateral' quinsies, associated with infectious mononucleosis and severe airway obstruction. The association, pathogenesis and significance of this finding are also discussed.

Acute Disease↗
PubMed1996

Outpatient management of diabetes mellitus in five Arizona Medicare managed care plans.

We report findings on the outpatient management of diabetes mellitus in Medicare beneficiaries enrolled in five Arizona Medicare-managed care plans. These findings are the baseline of an ongoing collaboration between the Health Services Advisory Group, Inc., Arizona's Peer Review Organization (PRO), and the five plans whose object is improved care of diabetes patients. The purpose of the study was to determine congruity between quality indicators identified by the five plans and the care actually received by diabetes patients enrolled in the five plans. The five plans agreed on a common set of quality indicators, including 10 services and 10 measures of patient status. Each plan has identified its diabetic population, 75 of whom are randomly selected each quarter by the PRO for chart review and inclusion in the study. The findings in this report cover two quarters of data. Data from chart review were examined to determine the extent to which actual practice reflected the indicators. The mean patient age was 71.8, and for most patients onset occurred between 55 and 69 years of age. About 25% had a positive family history, and we estimate the annual incidence of diabetes in this population to be about 1.1%. Mean hemoglobin A1c (HbA1c) was 8.9 +/- 2.1%; 46% were hypertensive; 42% continued to smoke cigarettes; 36% had retinopathy; 20% had proteinuria; and only 22% were on some kind of exercise program. Thirty-two percent were hospitalized during the 1-year baseline period, and the average number of outpatient visits per patient was 11.1 +/- 7.4. When care provided to diabetes patients enrolled in the plans was compared with the 10 quality standards identified by the plans themselves, only two of these standards was attained in more than 60% of patients: blood pressure, 98.7%; and foot examination, 62.7%. Two standards were achieved less than one-third of the time: urine dipstick, 10.4%, and appropriate use of angiotensin-converting enzyme (ACE) inhibitors, 31.25%. The others were all between 40 and 55%. Of the 10 service standards, about one-third received 1-4, one-third received 5-6, and one-third received 7-10. Only 5% of patients received 9 or 10 services. Outpatient management of diabetes patients in managed-care plans is similar to that in fee-for-service. When compared with fee-for-service or another HMO, a higher proportion of Arizona-managed care patients had HbA1c, and a much lower proportion had a dipstick test for urine protein. Values for other variables were usually within 10 percentage points of each other. Regardless of payment scheme, diabetes care is characterized by inconsistencies, omissions, and a lower than desirable level of services. Although few patients received most of the indicator services, diabetes patients are nevertheless high utilizers of medical care, both in and out of the hospital. The hospitalization rate is twice that of Arizona Medicare beneficiaries as a whole, and the number of office visits is three or four times that reported in other studies. Further, it seems that many visits are required to achieve even these modest service levels. Had the average number of visits been six or less, HbA1c rates, for example, would have fallen to less than one-third in three of the five plans. We believe that these data are conservative because it is likely that some and perhaps most of these indicators are underreported. It should be emphasized that these are baseline data whose purpose is to provide a basis against which subsequent improvements many be measured.

Aged↗
PubMed1995

Glioma in a goat.

An adult goat was examined because of behavioral changes and circling. Results of neurologic examination, CSF analysis, hematologic evaluation, and computed tomography of the brain were suggestive of an intra-axial mass. The goat was euthanatized because of worsening neurologic condition and poor prognosis. Necropsy revealed a large mass in the right cerebral hemisphere and caudal brain herniation through the foramen magnum. The mass was diagnosed as a glioma, with oligodendrocyte differentiation. Results of immunohistochemical evaluation were compatible with a malignant, poorly differentiated tumor.

Animals↗
PubMed1994

Amyotrophic lateral sclerosis patients' perspectives on use of mechanical ventilation.

Thirteen persons diagnosed with amyotrophic lateral sclerosis were interviewed to determine the factors involved in making a decision whether to use mechanical ventilatory support. All study participants believed that they alone should make the decision regarding use of mechanical ventilation. The factors they considered to be of most importance were quality of life, severity of disability, availability of ventilation by means of a nasal mask, possible admission to a long-term care facility, ability to discontinue use of mechanical ventilation, desire to live, concern for their families' emotional health, and concern for care demands placed on their families. Suggestions are offered to facilitate the patient's decision-making process through provision of more information and improved dialogue between patient and professional.

Amyotrophic Lateral Sclerosis↗
PubMed1986

Inhibition of rat neutrophil functional responses by azapropazone, an anti-gout drug.

Azapropazone at concentrations of 0.1 to 1 mM inhibited by 30-70% rat neutrophil migration, aggregation, and degranulation in response to the synthetic chemotactic peptide fMet-Leu-Phe. Binding studies using fNle-Leu-[3H]Phe, a radiolabeled analog of fMet-Leu-Phe, showed that azapropazone did not inhibit these responses by interfering with fMet-Leu-Phe binding. Azapropazone also decreased both the apparent rate of production and maximal levels of superoxide anion (O2-) generated by cells stimulated with 100 ng/ml phorbol-12-myristate-13-acetate (PMA). The concentrations of azapropazone that inhibit these neutrophil responses in vitro approximate those previously found in vivo after administration of therapeutic doses of drug to rats or humans. Taken together, the data suggest that the efficacy of azapropazone in gouty arthritis may be partly due to its ability to inhibit key neutrophil functional responses in vivo.

Animals↗
PubMed1986

Obstetric management of the very low birth weight fetus.

Obstetric management of the very low birth weight fetus (less than 1500 gm) is reviewed based on current literature. Issues of the pharmacologic therapy of preterm labor, enhancement of lung maturity, and management of labor and delivery are discussed.

Adrenal Cortex Hormones↗
PubMed1984

Fetal catecholamine release with preterm delivery.

Neurosympathetic system activity at birth was studied by measuring umbilical arterial plasma catecholamine concentrations in 36 preterm fetuses. Umbilical arterial catecholamine concentrations were correlated with blood gas status, mode of delivery, fetal sex, and fetal heart rate patterns. Significant correlations were observed for plasma norepinephrine and epinephrine versus fetal pH and PO2 and for plasma dopamine versus pH but not PO2. These catecholamine relationships to acidosis and hypoxia were similar to those of our previously published data for term fetuses. Norepinephrine and dopamine concentrations were similar in both preterm and term fetuses; however, epinephrine levels were significantly greater in preterm fetuses than in term fetuses. Increased concentrations of norepinephrine, epinephrine, and dopamine were observed in association with abnormal fetal heart rate patterns. There was no significant effect of fetal sex on the catecholamine secretory response. Similar cord catecholamine concentrations were observed following vaginal and cesarean section delivery, the latter with and without labor. These results indicate that the preterm fetus, like the term fetus, responds to stress at delivery with a graded catecholamine release. The observation of greater epinephrine concentrations in preterm fetuses than in term fetuses may reflect increased secretion or decreased clearance of epinephrine.

Dopamine↗
PubMed1982

An evaluation of a plastic strip thermometer.

The Clinitemp Fever Detector (a registered trademark for the Clinitemp Co, Indianapolis) is a plastic strip thermometer designed to be placed on the forehead and to detect body temperature by changing color. In a sample of 613 patients, we evaluated the ability of the Clinitemp to detect fevers detected by traditional mercury/glass thermometers. When a Clinitemp reading of 37.8 degrees C (100 degrees F) was used to demark fever, the Clinitemp detected 34% of the clinically significant fevers detected by the mercury/glass thermometers. The sensitivity of the Clinitemp rose to .81 when a Clinitemp reading of 37.2 degrees C (99 degrees F) was used to demark fever. The accuracy of the Clinitemp was affected by variations in ambient air temperature. A reassessment of previously published evaluations of plastic strip thermometers suggest that our results are consistent with other experimental findings. We conclude that the Clinitemp is unacceptable as a substitute for the mercury/glass thermometer.

Body Temperature↗
PubMed1979

A multidisciplinary clerkship in emergency medicine.

An obligatory, multidisciplinary, fourth-year emergency medicine clerkship is described and the particular problems of multidisciplinary courses discussed. The course is designed to produce medical students who adequately demonstrate: knowledge of emergency care and facility in specified skills, familiarity with the appropriate use of an emergency room, and conversance with treatment of nonemergency cases. Students are required to complete successfully an advanced cardiac life support providers course, serve on ambulance duty, rotate through a community hospital emergency room, and participate in the more traditional clinical experiences. The course offers the fourth-year student an opportunity to synthesize prior knowledge within the context of a multidisciplinary patient care experience.

Clinical Competence↗
PubMed1977

Quality assurance and the continuing education of physicians.

The rising impetus for mandatory continuing medical education (CME) is based on the assumption that CME presents an effective means of assuring physician competence. The relationship between competence and CME, as it currently exists, is unclear, however. The passage of legislation requiring mandatory CME credits will only serve to obscure this further by emphasizing quantity in credits rather than quality of educational experience.

Clinical Competence↗
PubMed1977

Cost factors in urban telemedicine.

This paper reports on the cost effectiveness of a pediatric primary care system utilizing nurse practitioners (NPs) linked to a physician consultant through bidirectional interactive cable television. In addition, it discusses ways in which multiple uses enhance the economic feasibility of a telemedicine consultation link in a given geographic area. The overall consultation rate during periods of remote physician coverage was 21 per cent, compared with 24 per cent during on-site coverage. The telephone became a partial substitute for the TV for some uses but could not replace it in diagnostic decisions. As telemedicine is obviously underutilized in a one-satellite system, we compare a five-satellite network with other ways of delivering service. The resulting estimated cost of $18.50 an hour, or 2/3 of the cost of a physician providing direct care, includes a TV component of $5.30 an hour of use in a 1,750-hour year. The critical factor is that the NP can be a physician substitute if there is TV backup. The TV appears to prevent unnecessary referrals compared to a physician on site. Whether TV increases the length of the consult compared to the phone for conditions of equal severity is not entirely clear. If TV is compared to transporting a patient to a central place, the implicit value of transport time and disutility required to justify using TV is $7.55 per consult in a five-clinic network. Geographic and other barriers to physician availability enhance the potential for application fo telemedicine.

Child↗
PubMed1977

Consumer health education and the problem of television.

The ubiquity of television and its ability to reach low income people make it an attractive medium for health education. However, its present influence on health is largely negative due to misleading or inaccurate commercials and program material. Efforts to provide accurate health information on television are difficult because of the financial structure of the industry, a mutual suspicion of health and television people toward each other, and possible legal entanglements involving constitutional issues. This paper suggests four ways which health people should consider in seeking to influence commercial television. None involve legislation, none threaten First Amendment guarantees, and none threaten the profit structure of the industry.

Advertising↗
PubMed1977

The use of cable television as a tool in health education of the elderly: screening.

A cable television channel was used to inform residents in a housing project for the elderly about a series of preventive health services. Screening and referral services for common health problems were offered to this group. The televised communications included a series of brief, informal advertising-style and direct teaching-style messages developed for each of five screening areas. An evaluation found that the televised messages had both direct and indirect effects on participation in the screening programs; overall attendance was about 8% of the estimated potential attendance. Knowledge and health attitude effects of the messages were also assessed.

Aged↗