Biomedical subjects

Peter C O'Brien

Publications and source records attributed to Peter C O'Brien.

42 records · Page 3Linked to original sources

PubMed2002

Medical services utilization and prognosis in Parkinson disease: a population-based study.

OBJECTIVES: To investigate prognostic outcomes and utilization of medical services by patients with Parkinson disease (PD) and to identify predictors of such use. PATIENTS AND METHODS: Using the medical records linkage system of the Rochester Epidemiology Project, we identified an incidence cohort of 89 PD cases (Olmsted County, Minnesota, 1979-1988) and a reference group of 89 subjects without PD of the same age and sex and from the same population. Both patients with PD and reference subjects were followed up historically by medical record review from onset of PD (or index year) through death, last contact with the system, or end of study. RESULTS: Patients with PD had significantly more physician consultations per year (median, 7.9 vs 5.9; P=.001) and more emergency department visits per year (median, 0.6 vs 0.4; P=.05) than did reference subjects. Response to dopaminergic medications and higher education predicted more physician consultations among patients. The PD patients used neuroleptics and antidepressants significantly more frequently than reference subjects. The risk of nursing home placement was significantly increased for PD patients compared with reference subjects (relative risk, 6.7; 95% confidence interval, 3.7-12.1; P<.001). Poor response to dopaminergic medications, lower education level, older age at onset of PD, and dementia predicted a shorter time between onset and nursing home placement among PD patients. Survival was significantly reduced in PD patients compared with reference subjects (relative risk, 2.2; 95% confidence interval, 1.4-3.4; P<.001). Good response to dopaminergic medications, higher education, younger age at onset of PD, and absence of dementia predicted better survival among PD patients. CONCLUSIONS: Patients with PD used outpatient and nursing home services more often than subjects without PD. Patients with PD also experienced a reduced survival time. Demographic and clinical characteristics influenced utilization patterns and outcomes.

Aged↗

PubMed1995

Double-blind, placebo-controlled study of the application of capsaicin cream in chronic distal painful polyneuropathy.

We have completed a 12-week double-blind, placebo-controlled randomized study on the efficacy of the application of capsaicin (CAPS) cream (0.075%) in the treatment of chronic distal painful polyneuropathy. Forty patients were enrolled and 39 completed the study. The 2 limbs were randomly assigned to CAPS or placebo (PLAC). The cream was applied 4 times a day. The first tube contained the active PLAC, methyl nicotinate. In the final 4 weeks (single-blind wash-out phase), PLAC was administered bilaterally. Efficacy was evaluated using the following scales: (1) investigator global, (2) patient global, (3) visual analog (VAS) of pain severity, (4) VAS of pain relief, (5) activities of daily living, and (6) allodynia. Patients were examined at onset and at monthly intervals using a neurologic disability scale, nerve conduction studies, computer-assisted sensory examination for vibration and thermal cooling and warming, QSART (quantitative sudomotor axon reflex test) and quantitative flare response. There was no statistical evidence of efficacy of CAPS cream over PLAC for any of the pain indices. At early time points (1-4 weeks), there were a small number of indices that favored the PLAC. The percent of limbs that improved on the investigator's global scale were 51.3 vs. 53.8 at 4 weeks, 56.4 vs. 64.1 at 8 weeks and 59 vs. 66.7 at 12 weeks for CAPS vs. PLAC; no statistically significant difference was found. All the safety indices showed no difference between sides. We interpret the early hyperalgesia on the CAPS side as being responsible for the better performance of PLAC at early time points. The large percentage of limbs that improved may be a pronounced PLAC response.

Adult↗

PubMedDate not supplied

Image quality in a standardized algorithm for minimally invasive coronary angiography with multislice spiral computed tomography.

PURPOSE: To report our experience with a standardized approach to pharmacologic heart rate control and image postprocessing for computed tomographic coronary angiography (CTCA) with multislice computed tomography (MSCT). METHOD: Two experienced observers used transaxial tomograms and maximum-intensity projections to classify coronary segments (12 per patient, 135 consecutive patients) for degree of stenosis. One factor affecting image quality was identified for each segment that could not be assessed. RESULTS: Nine patients (7%) were excluded for technical reasons. Of 1,512 segments from 126 patients, 1,086 (72%) were assessable (8.6 per patient). Of 300 segments from 25 patients who also had selective coronary angiography, CTCA was able to assess 211 (70%) and detected significant disease in 27 (82% sensitivity, 96% specificity, 73% positive predictive value, and 97% negative predictive value). Vessel caliber, heart rate, and Agatston score were associated with inability to assess 426 coronary segments (28%). CONCLUSION: Heart rate and Agatston score are important predictors of the ability to assess proximal and midcoronary segments by CTCA with MSCT.

Adult↗

PubMedDate not supplied

Nutritional assessment of serum and hepatic vitamin A levels in patients with cirrhosis.

BACKGROUND: Serum vitamin A (retinol) levels may not correlate with hepatic vitamin A stores in patients with cirrhosis; thus, supplementation of vitamin A based on serum levels may have a detrimental effect. Our aim was to determine whether serum levels correlate with hepatic stores in cirrhotic patients. METHODS: A prospective study of patients with cirrhosis undergoing orthotopic liver transplantation was completed. Serum and hepatic levels of vitamin A were measured by high-performance liquid chromatography. Statistical analysis was performed using rank sum tests and Spearman rank correlation coefficients. RESULTS: Fifty cirrhotic patients (33 men and 17 women, mean age 53 years) were compared with a control group (25 men and 25 women, mean age 47 years) of liver donors. Median serum levels of retinol were 259 microg/L in controls and 166 microg/L in cirrhotic patients (p < .001). Median hepatic levels of retinol were 25 microg/g in controls and 27.5 +/- g/g in cirrhotic patients (p not significant). Total hepatic vitamin A levels (retinol plus retinyl esters) were 471 microg/g in controls and 244 microg/g in cirrhotic patients (p = .028). Serum retinol did not correlate with total hepatic vitamin A stores in cirrhotic patients (rs = .10, p = .332). CONCLUSIONS: Serum retinol and total hepatic vitamin A stores are lower in cirrhotic patients than in controls. However, because levels of serum retinol do not correlate with hepatic vitamin A levels, the decision to prescribe vitamin A replacement for patients with cirrhosis should not be made solely on the basis of serum retinol levels.

Case-Control Studies↗

PubMedDate not supplied

Serum and hepatic vitamin E assessment in cirrhotics before transplantation.

BACKGROUND: Hepatic vitamin E may have a protective effect against hepatocyte injury; therefore, vitamin E replacement or supplementation may be beneficial in patients with cirrhosis. However, serum vitamin E may not correlate with hepatic vitamin E stores, making decisions regarding treatment difficult based on serum levels alone. The specific aims of this study were to determine hepatic concentrations of vitamin E and to determine whether serum levels of vitamin E correlate with hepatic vitamin E stores in cirrhotics. METHODS: A prospective study of cirrhotics undergoing orthotopic liver transplantation (OLT) was completed. Serum and hepatic levels of vitamin E were measured by high-performance liquid chromatography. Statistical analysis was performed using rank sum tests and Spearman's rank correlation coefficient. RESULTS: Fifty cirrhotics (33 males, 17 females; mean age of 53 years) were studied. The control group (25 males, 25 females; mean age of 47 years) consisted of the liver donors. The median serum levels of vitamin E in controls and cirrhotics were 5.95 and 7.8 mg/L, respectively (p = .009). The median hepatic levels (0.10 mg/g) in the control and cirrhotic groups were similar (p = .037). There was a significant correlation between serum and hepatic vitamin E levels in cirrhotics (R = 0.335; p = .017). CONCLUSIONS: A positive correlation exists between serum and hepatic concentrations of vitamin E in cirrhotics, therefore making serum vitamin E levels a useful reference for treatment using exogenous vitamin E.

Chromatography, High Pressure Liquid↗

PubMedDate not supplied

Glucose counterregulatory hormones in the 72-hour fast.

OBJECTIVE: To attempt to establish a reference range of glucagon concentrations during hypoglycemia. METHODS: We measured glucagon, cortisol, and growth hormone responses in 65 patients with insulinoma and 29 normal control subjects who underwent a 72-hour fast. For comparison, we also assessed these responses in eight patients with noninsulinoma pancreatogenous hypoglycemia syndrome. RESULTS: At the end of the fasts, median serum cortisol (19.0 mg/dL [range, 3.7 to 44.0] versus 11.0 mg/dL [range, 5.0 to 28.0], respectively; P<0.001) and growth hormone levels (3.5 ng/mL [range, 0.1 to 46.0] versus 1.2 ng/mL [range, 0.1 to 34.0], respectively; P = 0.021) were higher, whereas plasma glucagon (54.5 pg/mL [range, 11.0 to 170.0] versus 75.0 pg/mL [range, 17.0 to 940.0], respectively; P = 0.012) was lower in patients with insulinoma (serum glucose level, 39 mg/dL [range, 14 to 58]) than in control subjects (serum glucose level, 63 mg/dL [range, 47 to 89]). In contrast, the 8 patients with noninsulinoma pancreatogenous hypoglycemia syndrome, a disorder of postprandial hyperinsulinemic hypoglycemia with normal findings on a 72-hour fast (serum glucose level, 71.5 mg/dL [range, 48 to 82]), had concentrations of glucagon (81.0 pg/mL [range, 47.0 to 150.0]), cortisol (10.5 mg/dL [range, 2.7 to 17.0]), and growth hormone (1.5 ng/mL [range, 0.8 to 6.9]) similar to those in the control subjects. On multivariate analysis, the duration of the fast, baseline glucagon concentration, and male gender (but not age, body mass index, or concentrations of glucose and insulin) were correlated with end-of-fast glucagon concentration. CONCLUSION: Defective glucagon secretion in hypoglycemic disorders applies to the stimulus of hypoglycemia but not to food deprivation. A conservative estimate for glucagon deficiency based on the minimal observed glucagon response could be a level of 10 pg/mL during hypoglycemia.

Adult↗