PubMed Health⌕ Search

Biomedical subjects

D K O'Brien

Publications and source records attributed to D K O'Brien.

9 recordsLinked to original sources
PubMed1994

Halothane inhibits bradykinin-stimulated prostacyclin production in endothelial cells.

BACKGROUND: Halothane and isoflurane alter signal transduction and function in several cell types. Vascular responses to these anesthetics may be attributable to agent-specific effects on vasoactive mediator production. This study investigated the effects of halothane and isoflurane on basal and agonist-stimulated prostacyclin production by endothelial cells. METHODS: Prostacyclin production by cultured bovine aortic endothelial cells was monitored by radioimmunoassay of 6-keto-prostaglandin F1 alpha, the stable breakdown product of prostacyclin. RESULTS: Neither halothane nor isoflurane (0.3-1 mM), altered prostacyclin production. Bradykinin (1 microM), adenosine triphosphate (ATP) (10 microM), and melittin (1 microgram.ml-1) stimulated prostacyclin production. Isoflurane had no effect on responses to bradykinin, ATP, or melittin. Halothane inhibited the response to bradykinin but not the response to ATP or melittin. Pretreatment with pertussis toxin (100 ng.ml-1), to inhibit the function of the guanosine triphosphate-binding protein G alpha i, did not alter the response to bradykinin in the presence or absence of halothane. Pretreatment with phorbol 12-myristate 13-acetate (100 nM), to stimulate protein kinase C activity, did not alter bradykinin-stimulated prostacyclin production and prevented the inhibition of the response to bradykinin by halothane. CONCLUSIONS: Isoflurane had no effect on the increase in prostacyclin production stimulated by bradykinin. Halothane inhibited the bradykinin-stimulated prostacyclin production but not that stimulated by ATP or melittin. These results suggest that the halothane-mediated inhibition of bradykinin-stimulated prostacyclin production does not involve a pertussis toxin-sensitive G-protein and may result from an interaction of halothane at some other step in the signal transduction pathway, including the inhibition of protein kinase C.

Adenosine Triphosphate↗
PubMed1987

The diagnostic process in primary care: a comparison of general internists and family physicians.

This investigation examined the formulation of diagnostic hypotheses by general internists and family physicians in response to three patient cases (dyspnea, abdominal pain and syncope). The investigation was conducted in the United States. Physician responses to sequentially presented written clinical information were audiotaped. Each transcribed protocol was scored to enumerate and characterize the hypotheses considered by physicians in each specialty. Results of the analyses of variance of hypothesis measures revealed that internists generated more hypotheses than family physicians and that the internist's hypotheses were more specific and were less likely to be generated by other physicians. In addition, internists tended to consider hypotheses more closely related to the final diagnosis sooner in the case presentation than did family physicians. The findings of increased number, specificity, and uniqueness of hypothesis considered by internists are consistent with previously demonstrated differences in the amount and nature of diagnostic information collected by family physicians and internists.

Diagnosis, Differential↗
PubMed1987

Resident test ordering patterns.

Utilization of a selected set of laboratory tests in the ambulatory setting was determined for four classes of family practice residents over their entire three year training program. A total of nineteen residents were included in the study. Residents' test utilization in their third year of training was significantly lower than in their Post Graduate Year I (PGY I) and PGY II years. Though there was a substantial drop in residents' utilization between their first and second year, the drop was not significant. While most residents reduced their test utilization as they progressed through residency, several who were extremely low utilization in there first year of training actually increase test utilization in the second year. There was substantial variation in residents' test utilization, most marked in the first year but persisting for all three years. Although test utilization progressively fell through the three years of training, the residents who were high utilizers during their first year of training remained high utilizers for the remainder of their training. Though the variation in resident test utilization apparent in PGYI was maintained throughout residency, the degree of variation was reduced and greater uniformity was achieved as training progressed.

Clinical Laboratory Techniques↗
PubMed1986

Student and faculty assumptions about the nature of uncertainty in medicine and medical education.

Clinical reasoning involves an element of uncertainty. Teaching clinical reasoning involves understanding how students view uncertainty as well as how medical problems are solved. This study uses Perry's model of intellectual development to explore changes in how medical students, residents, and instructors think about the nature of knowledge. A total of 31 medical students, residents, and instructors completed the Widick and Knefelkamp Measure of Intellectual Development revised to focus specifically on uncertainty in medicine. Consistent with Perry's theory, scores reflected increasing degrees of acceptance of the role of uncertainty in medicine with increasing experience. Based on these results, it is concluded that to improve the effectiveness of teaching problem solving in medicine, faculty must challenge the assumptions held by medical students about the certainty of medical knowledge while teaching the process of clinical diagnosis.

Attitude↗
PubMed1982

Diuretic induced hypokalemia in the elderly.

The effects of four commonly prescribed diuretics on serum potassium were assessed. One hundred sixteen elderly clinic patients, independently living, (mean age 74.3 years, range 60 to 99 years) were taking hydrochlorothiazide (HCTZ) (n = 40; mean daily dose, 53.9 mg), a combination of hydrochlorothiazide-triamterene (HCTZ-TMTR) (n = 38; mean daily dose, 1.28 capsules), furosemide (n = 20; mean daily dose, 38.0 mg), or chlorthalidone (n = 18; mean daily dose, 55.6 mg). Patients did not take more than one diuretic. No patients received potassium supplementation or had diseases affecting potassium balance. The study design was a nonblinded, noncrossover retrospective chart audit with chi-square analysis. All patients were counseled about reducing excessive sodium intake and using potassium-rich foods and salt substitutes, although compliance concerning these dietary factors was not assessed. Even though some comparisons of diuretics showed statistical significance, these differences probably are not clinically significant because all serum potassium values were above 3.0 mEq/L and no patient was symptomatic. This study supports the use of HCTZ as an initial antihypertensive diuretic; it is as efficacious as the other diuretics in this study, is less expensive, and usually does not cause clinically significant hypokalemia more often than do the other diuretics.

Aged↗
PubMedDate not supplied

Effects of introducing an office chemistry machine.

An office chemistry machine was placed into service at the SIU Springfield Family Practice Center. After one year's use of the machine, a study was performed to learn whether there were changes in the methods, of costs, and of care for hypertensive patients compared to the year before introduction of the machine. After introduction of the machine, the physicians began to order individual tests performed in the office rather than chemistry panels performed by the reference laboratory. There was no change in the frequency or costs of testing. Frequency of visits for hypertension and visits for all other reasons did not differ. The level of blood pressure control was the same before and after introduction of the machine. Thus, in this study, introduction of an office chemistry machine resulted in greater revenues to the clinic without changing quality of care or increasing the overall cost of treatment.

Blood Chemical Analysis↗
PubMedDate not supplied

A model of computer documentation of hospital specialty rotations.

The importance of a comprehensive documentation system for assisting residents in securing hospital privileges has been widely asserted. Other applications of a documentation system such as encouraging research, providing individual resident evaluations, and providing program evaluation are also worthy reasons for developing a system. This paper describes a computerized system for documenting the inpatient rotation experiences of family practice residents and discusses its potential applications. An example of curriculum evaluation as a use of a documentation system is detailed.

Computer Systems↗