Biomedical subjects

D W Mahoney

Publications and source records attributed to D W Mahoney.

45 records · Page 3Linked to original sources

PubMed1996

Atropine augmentation in dobutamine stress echocardiography: role and incremental value in a clinical practice setting.

OBJECTIVES: This study sought to evaluate the role and incremental value of atropine in a large patient group undergoing dobutamine stress echocardiography. BACKGROUND: The use of atropine to potentiate dobutamine stress is not standard practice. Although the utility of atropine has been described, data on its incremental value remain limited and do not exist for a routine clinical practice setting. METHODS: Dobutamine stress echocardiography was performed in 1,171 patients with use of a standard protocol. Atropine (maximal dose 2.0 mg) was given to 299 patients (26%) who did not attain target heart rate. Coronary angiography was performed in 183 patients (46 received atropine), 148 of whom were found to have significant coronary artery disease (> or = 70% diameter stenosis in a major epicardial vessel, > or = 50% stenosis for left main coronary artery disease). All tests were reviewed independently by experienced observers. RESULTS: There were no major adverse events. Patients receiving atropine had a lower rest heart rate (65 vs. 74 beats/min, p < 0.0001) and more often received beta-adrenergic blocking agents (49% vs. 14%, p < 0.0001). Of 444 patients in whom stress-induced ischemia developed, 70 (16%) required atropine before ischemia became evident. Sensitivity for detection of significant coronary artery disease was 90% with dobutamine alone and 95% after the addition of atropine. In 66 patients with normal wall motion at rest, test sensitivity was 65% before and 84% after atropine was given. Atropine use did not compromise test specificity. New diagnostic information was obtained in 20 (50%) of 40 patients with angiographic coronary artery disease given atropine. Proportionately more patients with single-vessel disease required atropine before an ischemic response was observed; this effect appeared related to the higher ischemic threshold in these patients. CONCLUSIONS: Augmentation of heart rate had a modest influence on the overall diagnostic sensitivity of dobutamine stress echocardiography in our study cohort. However, it was particularly helpful in patients receiving beta-blockers and those with milder coronary disease. Despite the use of > or = 1 mg of atropine in some patients, this incremental value was not achieved at the expense of safety.

Adult↗

PubMed1996

Risk of colorectal neoplasia in patients with primary sclerosing cholangitis.

BACKGROUND & AIMS: Studies implicating primary sclerosing cholangitis as a risk factor for colorectal neoplasia in patients with ulcerative colitis have been limited by small sample size and referral bias. The aim of this study was to determine the relative risk and cumulative incidence of colorectal neoplasia in a large sample of patients with sclerosing cholangitis. METHODS: A sample of patients with primary sclerosing cholangitis (n = 178), stratified by geographic area of residence, was identified and followed up to determine survival and development of colorectal neoplasia. The relative risk of colorectal cancer was determined using age- and sex-specific incidence rates of colorectal cancer in the U.S. general population as well as rates in patients with ulcerative colitis from central Sweden. RESULTS: The relative risk of colorectal cancer was elevated 10-fold (standardized morbidity ratio, 10.3; 95% confidence interval, 2.1-30) compared with the general population for exposure to both sclerosing cholangitis and colitis but not cholangitis alone (standardized morbidity ratio, 4.9; 95% confidence interval, 0.1-27). The observed number of cancers was similar to that expected on the basis of rates in Swedish patients with ulcerative colitis. CONCLUSIONS: If primary sclerosing cholangitis is an additional risk factor for neoplasia in ulcerative colitis, the clinical significance of the risk seems to be low.

Adenocarcinoma↗

PubMed1996

Primary sclerosing cholangitis is associated with nonsmoking: a case-control study.

BACKGROUND & AIMS: Cigarette smoking is thought to protect against the development of ulcerative colitis. The relationship between a related disease, primary sclerosing cholangitis, and smoking is unknown. The aim of this study was to determine if the relationship between smoking and sclerosing cholangitis is similar to that found between smoking and ulcerative colitis. METHODS: A stratified sample of 184 patients with primary sclerosing cholangitis and age- and sex-matched institutional control subjects were identified. Smoking information was obtained from a medical questionnaire completed at the time of visit. RESULTS: Eighty-one percent of the patients had associated inflammatory bowel disease. Only 4.9% of them were current smokers compared with 26.1% of the controls; 69.6% of the patients had never smoked vs. 46.7% of the controls. The estimated odds of having primary sclerosing cholangitis in current smokers compared with never-smokers was 0.13. The odds of having disease among former and current users of any tobacco relative to never-users was 0.41 regardless of the presence or absence of inflammatory bowel disease. CONCLUSIONS: The odds of having primary sclerosing cholangitis was significantly decreased among current smokers. Concomitant ulcerative colitis does not fully explain the association between nonsmoking and primary sclerosing cholangitis. Smoking may exert its protective effect in a systemic, rather than colonic, manner.

Adult↗

PubMed1996

Azathioprine pharmacokinetics after intravenous, oral, delayed release oral and rectal foam administration.

BACKGROUND: 6-Mercaptopurine and its prodrug azathioprine are effective medications for refractory inflammatory bowel disease. However, use of these drugs has been limited by concerns about their toxicity. Colonic delivery of azathioprine may reduce its systemic bioavailability and limit toxicity. AIM: To determine the bioavailability of 6-mercaptopurine after administration of azathioprine via three colonic delivery formulations. METHODS: Twenty four healthy human subjects each received 50 mg of azathioprine by one of four delivery formulations (each n = 6): oral; delayed release oral; hydrophobic rectal foam; and hydrophilic rectal foam. All subjects also received a 50 mg dose of intravenous azathioprine during a separate study period. Plasma concentrations of 6-mercaptopurine were determined by high pressure liquid chromatography. RESULTS: The bioavailabilities of 6-mercaptopurine after colonic azathioprine administration via delayed release oral, hydrophobic rectal foam, and hydrophilic rectal foam (7%, 5%, 1%; respectively) were significantly lower than the bioavailability of 6-mercaptopurine after oral azathioprine administration (47%) by Wilcoxon rank sum pairwise comparison. CONCLUSIONS: Azathioprine delivered to the colon by delayed release oral and rectal foam formulations considerably reduced systemic 6-mercaptopurine bioavailability. The therapeutic potential of these colonic delivery methods, which can potentially limit toxicity by local delivery of high doses of azathioprine, should be investigated in patients with inflammatory bowel disease.

Administration, Oral↗

PubMed1996

Fecal marker variability in colorectal cancer: calprotectin versus hemoglobin.

BACKGROUND: Blood products like hemoglobin are problematic as markers for colorectal neoplasia because bleeding is intermittent. Levels of calprotectin, a leukocyte-derived protein, are increased in stools from colorectal cancer patients. However, this blood constituent may gain luminal access via interstitial leukocyte migration, which could be a less variable mechanism of entry than bleeding. METHODS: To correlate the levels of and to compare the variability of fecal calprotectin and hemoglobin, quantitative assays were performed independently on multiple serially collected stools from 14 patients with colorectal cancer. Marker level association was estimated with Pearson's correlation coefficient, and variation estimated with an analysis of variance model. RESULTS: Fecal calprotectin and hemoglobin levels were discordant in 55 (50%) of 110 matched aliquots, and marker levels failed to correlate. The estimated between-subject correlation was -0.10 (95% CI, -0.60 to 0.46), and mean within-subject correlation -0.27 (95% CI, -0.73 to 0.34). The between-stool coefficient of variation was less for calprotectin (22%) than for hemoglobin (80%). CONCLUSIONS: In patients with colorectal cancer, the mechanism of luminal calprotectin entry appears to be both different from and less erratic than bleeding.

Aged↗

PubMed1995

Normal stroke volume and cardiac output response during dobutamine stress echocardiography in subjects without left ventricular wall motion abnormalities.

Dobutamine stress echocardiography has become widely utilized for evaluation of coronary artery disease, but the expected responses of stroke volume and cardiac output to the high doses of dobutamine administered in these studies are not known. To determine these responses, stroke volume and cardiac output were measured with 2-dimensional Doppler echocardiography at each stage of dobutamine stress echocardiography and after administration of atropine in 47 patients without resting or inducible wall motion abnormalities. Heart rate increased significantly at each stage of dobutamine infusion and after atropine. Mean blood pressure decreased at the 5 micrograms/kg/min dose, then showed little change. Stroke volume increased 27 +/- 18% from baseline, with significant increases occurring at both the 5 and 10 micrograms/kg/min doses (p < 0.00001). With higher doses of dobutamine, stroke volume tended to plateau or decrease. Mean changes in stroke volume were not significant between the doses of 10, 20, and 30 micrograms/kg/min. The mean change in stroke volume from the 30 to the 40 micrograms/kg/min dose was a significant decrease of 6.3% (p = 0.004); the decrease from the 40 micrograms/kg/min dose to atropine approached statistical significance (p = 0.06). Cardiac output increased throughout dobutamine infusion. Stroke volume during dobutamine stress echocardiography is commonly maximum at a dose of 20 micrograms/kg/min and tends to decline at higher infusion rates. At higher doses, increases in cardiac output are mediated primarily by increases in heart rate.

Aged↗

PubMedDate not supplied

Using nursing diagnoses and interventions in an inpatient amputee program.

The purpose of this study was to provide a descriptive analysis of an inpatient amputee program at Spaulding Rehabilitation Hospital (SRH) in Boston; the analysis focused on nursing diagnoses and interventions documented in the medical record. The study was based on a retrospective chart review conducted for 96 inpatient lower-extremity amputees who were admitted from October 1988 through September 1989. The results of the study identified common nursing diagnoses and interventions used for a medically complex population of people who had had amputations. In addition, the study showed that most subjects improved in functional status, thus confirming the success of the program. All subjects were either discharged to their homes or transferred to an acute care facility. The study results will be used to develop a standardized nursing care plan, as well as creative new modalities for patient and family education, at SRH.

Amputees↗

PubMedDate not supplied

An optimal dual-size vial system for the cost-effective usage of Adenoscan.

BACKGROUND: Adenoscan (Fujisawa USA, Inc., Deerfield, Ill.) has been initially packaged in a 30 ml glass vial for single use only because it contains no preservative. This restricted usage has generated considerable waste and high cost for the patient. Although the new 20 ml vial of Adenoscan provides some reduction in waste, the savings offered by the 20 ml and 30 ml vial system is still not optimal. The purpose of this study was to investigate an optimal dual-size vial system that would provide limited amounts of waste while maintaining its practicality to satisfy different patient populations. MATERIALS AND RESULTS: The least waste for each potential combination (n = 344) of two vials was calculated by assuming that patient weights (30 to 200 kg) follow a normal distribution. The 6 ml and 15 ml vial combination had the least expected waste for lighter patient populations, and the 9 ml and 15 ml vial system had the least expected waste for heavier populations. The calculated wastes for 4207 patients (83 +/- 19 kg) undergoing adenosine stress myocardial perfusion studies at the Mayo Clinic were 10.5 +/- 9.3 ml (30 ml vial), 5.1 +/- 2.9 ml (20 ml and 30 ml vial system), 1.6 +/- 1.0 ml (6 ml and 15 ml vial system), and 1.8 +/- 1.2 ml (9 ml and 15 ml vial system). CONCLUSIONS: In general, both the 6 ml and 15 ml and 9 ml and 15 ml vial systems perform better than either the single 30 ml vial or the 20 ml and 30 ml vial system. Furthermore, the 6 ml and 15 ml vial combination offers the lowest expected waste for the actual patient population that underwent the adenosine stress myocardial perfusion imaging studies at our institution.

Cost-Benefit Analysis↗

PubMedDate not supplied

Evaluation of macroaggregated albumin particle sizes for use in pulmonary shunt patient studies.

OBJECTIVE: To assess commercial macroaggregated albumin (MAA) reagent kits for compliance with particle-size parameters needed for proper clinical evaluation of pulmonary shunts (right-to-left). DESIGN: Comparative trial. SETTING: Nuclear pharmacy (laboratory setting). PATIENTS AND OTHER PARTICIPANTS: Not applicable. INTERVENTIONS: Minimally, 90% of the particles contained within an MAA reagent kit should be within the 10 to 90 microns range with minimal variation in particle size distribution and as few small particles (i.e., < 10 microns) as possible. Five separate vials from five commercial brands of MAA reagent kits were obtained, and 500 to 517 particles were analyzed for each sample. An additional study was performed on one of the MAA reagent kit brands, using five vials from each of five different lot numbers to determine the variability between lots. MAIN OUTCOME MEASURES: Long axis (maximum, micron), short axis (minimum, micron), and the area (micron 2) of each MAA particle. RESULTS: One MAA brand had the lowest percentage of unacceptable MAA particle sizes and maintained consistent particle sizes between vials. However, the same MAA reagent kit brand showed that only two of five lots had a low percentage of MAA particle sizes below the 10-micron limit. CONCLUSION: Particle sizes varied among the five different brands of MAA reagent kits, as did different lots of the best-performing kit. This variability in particle sizes may affect the accuracy and reproducibility of pulmonary shunt patient studies.

Humans↗