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Biomedical subjects

P C O'Brien

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

At least 253 records · Page 14Linked to original sources
PubMed1988

Incretin effect due to increased secretion and decreased clearance of insulin in normal humans.

To assess the contribution of changes in insulin secretion and clearance to the incretin effect (greater insulinemia after oral than after intravenous glucose), 10 healthy subjects were studied after oral glucose (1 g/kg body wt) and again when glucose was infused intravenously at rates to match arterialized plasma glucose concentrations after oral glucose. Although basal and integrated plasma glucose did not differ between oral and intravenous glucose, integrated responses of insulin (3.3 +/- 0.5 vs. 1.8 +/- 0.4 mU ml-1.240 min-1, P less than .001), C-peptide (456.5 +/- 58.5 vs. 327.9 +/- 46.3 ng.ml-1.240 min-1, P = .002), gastric inhibitory polypeptide, (16.8 +/- 3.5 vs. -2.8 +/- 1.0 micrograms.ml-1.240 min-1, P less than .001), and insulin secretion (6.6 +/- 1.1 vs. 4.7 +/- 0.7 U.240 min-1, P = .003) were greater with oral than intravenous glucose. However, insulin clearance, whether calculated as the molar ratio of integrated C-peptide to integrated insulin responses (6.9 +/- 0.7 vs. 14.2 +/- 3.8, P = .005) or from the formula insulin clearance equals insulin secretion divided by integrated insulin responses (1.1 +/- 0.2 vs. 2.5 +/- 0.7 L.min-1.m-2, respectively, P = .002), was less for oral than for intravenous glucose. Therefore, the incretin effect is mediated both by increased secretion and decreased clearance of insulin.

Administration, Oral↗
PubMed1988

Late cerebrovascular accidents after repair of abdominal aortic aneurysms.

In this follow-up of 1,112 patients operated on for abdominal aortic aneurysm (AAA) it was noted that cerebrovascular accidents (CVAs) caused significant (8.2%) late mortality. Seventy-one patients developed non-fatal or fatal CVAs at 5.9 +/- 2.9 (mean +/- SD) years after the initial aneurysm repair. The incidence of CVA was 4.2% and 9.5% within five and ten years, respectively. In patients with preoperative evidence of both hypertension and heart disease, the incidence of CVA within five years was 9.1% compared to an incidence less than 4% in patients with either or neither of these risk factors (p less than 0.01). Multivariate analysis of individual risk factors revealed that only age (p less than 0.001), hypertension (p less than 0.001), angina pectoris (p less than 0.02) and other heart disease (p less than 0.001) were independently associated with a reduced survival free of CVA. Thus, cerebrovascular accidents are responsible for significant late morbidity after AAA repair. Patients at high age or with evidence of hypertension and heart disease carry a greater risk for this complication.

Adult↗
PubMed1987

Relationship between androgen receptor binding activity in human prostate cancer and clinical response to endocrine therapy.

The authors investigated the ability of androgen receptor binding in prostate cancer tissue to predict the response of prostate cancer patients to endocrine therapy. The clinical response of 37 previously untreated patients with various grades and stages of prostate cancer was correlated with androgen receptor binding and detailed histologic data obtained before treatment. All patients underwent cold-punch transurethral resection of the prostate and received endocrine therapy. The association between time to progression and cytosolic androgen binding was not significant. However, the associations of time to progression to nuclear binding and to total androgen binding were significant (P = 0.029 and 0.038, respectively). The authors found no association between clinical stage and time to progression, but did find an association between time to progression and pathologic grade (P = 0.003); grade 4 lesions were the least responsive to hormone therapy. When grade 4 lesions were excluded (N = 3), binding levels were still predictive of progression independently of grade and stage. The authors conclude that nuclear receptor binding activity in localized and metastatic prostate cancer tissue is predictive of response to hormonal manipulation.

Aged↗
PubMed1987

Assessment of nerve damage in the feet of long-distance runners.

To answer the question, "Does long-distance running injure nerves of the feet and legs?" we invited the 25 members of the Rochester Track Club who had run the greatest number of miles in their lifetime to participate in a study that involved neurologic examination, determination of detection thresholds of touch-pressure, vibratory, and cooling sensations of the foot, and evaluation of nerve conduction. None of the runners had clinical symptoms or signs of peripheral neuropathy. Most of them reported having had toe and foot injuries, sometimes associated with short-lived sensory symptoms. A computer-assisted sensory evaluation of the detection threshold for vibratory sensation of the toe revealed slightly, but significantly, higher values in the runners in comparison with age- and sex-matched control subjects. Similarly, small, but statistically significant, differences were also observed for some attributes of nerve conduction in the leg and foot nerves of the runners. These results suggest that long-distance running causes multiple small injuries to the toes and feet, which lead to measurable differences in the detection threshold for vibratory sensation and in nerve conduction but not to overt neuropathy. The trivial subclinical neuropathic deficits we noted are readily offset by the assumed health and recreational benefits of running.

Adolescent↗
PubMed1987

Magnetic resonance imaging and clinical relationships in multiple sclerosis.

Magnetic resonance imaging (MRI) was done in 109 patients with suspected demyelinating disease (56 with clinical multiple sclerosis [MS] and 53 without). Of those with clinical MS, 43 (77%) had multifocal lesions of the white matter detected on MRI; 12 of the 43 also had confluent periventricular signaling. Nine patients (17%) without clinical MS had similar findings. Of the 56 patients with MS, 35 underwent both computed tomography (CT) and MRI. In this group, 80% of MRI scans showed multiple demyelinating lesions compatible with MS, as compared with 29% of the CT scans. A CT scan was "positive" more often if obtained within 1 month after an attack of MS than later. In contrast, the sensitivity of MRI or the number of lesions detected by MRI did not increase in patients with recent exacerbations. MRI was "positive" in patients with clinical MS more often than was any single evoked response study. In statistical analyses, both the sensitivity of MRI and the number of lesions were associated with the duration of MS. A pattern of confluent periventricular signaling around the lateral ventricle was associated with greater duration of MS and patient disability.

Adult↗
PubMed1987

Coital risk factors for cervical cancer. Sexual activity among white middle class women.

This study reports the sexual history of a group of young women participating in an epidemiologic project. The methods used to recruit and interview the participants minimized self-selection bias. Results of over 11,000 interviews with 1,892 participants showed that 72.3% should be considered at high risk for developing cervical cancer and its precursors and should be screened regularly for this disease.

Adolescent↗
PubMed1987

Merkel cell carcinoma: a review of behaviour patterns and management strategies.

Eleven patients with Merkel cell carcinoma of the skin were reviewed retrospectively. The aggressive nature of this tumour is reflected by the incidence of local recurrence, regional nodal metastases and systemic dissemination, which is 36%, 55%, and 18% respectively. This high frequency of local recurrence and metastases is confirmed in the literature. Management strategies should be planned accordingly, following accurate assessment of the extent of disease. Wide excision, with or without nodal dissection, together with adjuvant wide field irradiation is necessary for loco-regional control of this radiosensitive tumour. Radiotherapy alone may be appropriate treatment for extensive loco-regional tumours or in those that have already metastasized. Although the role of chemotherapy is unclear, there are an increasing number of reports of chemosensitivity and further investigation in this area is required.

Aged↗
PubMed1987

Discriminant analysis of the Self-Administered Alcoholism Screening Test.

For a sample of 1156 patients (520 alcoholics and 636 nonalcoholics), discriminant function analyses were performed on the total score, a nine-item version, and a two-item version of the Self-Administered Alcoholism Screening Test (SAAST). With sensitivities set at 90 and 95%, specificities for the total score and nine-item versions ranged from 96.4 to 99.4%. Cross-validation of the nine-item version with the "jackknife" procedure resulted in only one additional misclassification of the 1156 subjects. Separate analyses of the male and female samples revealed that more items entered the discriminant function for women than for men and resulted in a higher, although clinically nonsignificant, percentage of correct classification for women. The results strongly support the use of either the total score or the nine-item version of the SAAST in large-scale screening for alcoholism in a medical patient population.

Adult↗
PubMed1987

Renovascular operations in patients with chronic renal insufficiency: do the benefits justify the risks?

To define the benefits and risks of renal revascularization or nephrectomy in patients with both severe hypertension and chronic renal insufficiency, we analyzed 98 patients who underwent renovascular operations after serum creatinine levels exceeded 2 mg/dl. This subset of patients was selected from a retrospective review of 652 renal operations performed at the Mayo Clinic for renovascular disease between 1970 and 1981. Special attention was given to the type of operations, their effect on hypertension and renal function, specific factors that affected operative deaths, and late survival. Unilateral renal operations were performed in 48 patients with bilateral procedures in 50. Simultaneous aortic reconstruction was necessary in 55 patients (56%). Postoperative diastolic blood pressure was less than 90 mm Hg in 55% of patients and 90 to 100 mm Hg in an additional 33%. Seventy-six percent of patients required less antihypertension medication. Serum creatinine improved or stabilized in 69%. Ninety percent of patients avoided any early or late renal dialysis. The operative mortality rate was 7.1% and tended to be higher in patients with a serum creatinine greater than 3 mg/dl and in those with past myocardial infarction (p = 0.05). The late survival rate was 64% at 5 years. The main cause of operative and late death was myocardial infarction. In conclusion, most patients with renovascular hypertension and early chronic renal insufficiency can be benefited by surgical revascularization or nephrectomy. Future improvement in early and late survival may require a more aggressive approach to the identification and correction of significant coronary artery disease.

Adult↗
PubMed1987

Late survival in abdominal aortic aneurysm patients: the role of selective myocardial revascularization on the basis of clinical symptoms.

Coronary artery disease is recognized as the major cause of perioperative and late death after abdominal aortic aneurysm (AAA) repair. Routine coronary angiography and prophylactic myocardial revascularization for all significant lesions, regardless of symptoms, have been recommended as a means of reducing this mortality risk. We have advocated a more selective approach in which coronary angiography and myocardial revascularization are performed on the basis of cardiac symptoms. Studies have shown that this selective approach is just as effective as the prophylactic approach in reducing perioperative deaths. To evaluate the effect on late survival of selective myocardial revascularization on the basis of symptoms, we reviewed the preoperative coronary status and course of 485 patients who successfully underwent AAA repair between 1980 and 1985. Late survival was evaluated by means of the Kaplan-Meier method and compared with life expectancy of an age- and sex-matched population. Late survival of the entire group of patients was no different from that of the matched population. Patients with no preoperative evidence of coronary artery disease did significantly better than expected (p = 0.05), whereas those patients with uncorrected or previously bypassed coronary disease had survival no different from that expected. When age was considered as a variable, patients in their 50s and 60s had survival significantly worse than the matched population (p less than 0.001 and p = 0.003, respectively). Patients in their 70s and 80s had survival as good as or better than the matched population, regardless of coronary status.(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗
PubMed1986

A study of out-of-hospital cardiac arrests in northeastern Minnesota.

Training in advanced cardiac life support and defibrillation and community programs in cardiopulmonary resuscitation (CPR) had limited success in resuscitating patients with cardiac arrest in the Arrowhead region of Minnesota. Factors associated with survival included advanced cardiac life support within 16 minutes, ambulance traveling less than 1 mile (less than 1.6 km), use of paramedics, CPR within four minutes, and a call for help within two minutes. The use of technicians trained in defibrillation was associated with a statistically significant increase in hospital admissions, but not in survivors. The study failed to confirm the findings of previous studies of resuscitation in some rural areas. It was consistent, however, with reports that associated poor survival in rural areas with poor response times. No victims of unwitnessed arrests survived. Of the hospital deaths, 80% were due to neurologic causes, and overall survival was low.

Adult↗
PubMed1986

Prognostic factors in choroidal and ciliary body melanomas with extrascleral extension.

In a retrospective study, 50 (8.2%) of 610 patients with malignant melanoma of the ciliary body or choroid had extrascleral extension. Of 46 patients for whom follow-up data were available, 24 (52%) survived five years, 20 (42%) survived ten years, and 17 (37%) survived 15 years. Factors that seemed to affect survival significantly included intraocular tumor size and extraocular tumor size and location. Our observations did not support the role of primary exenteration. Five patients (11%) with extrascleral extension had orbital recurrences and all died within 31 months of surgery regardless of treatment.

Adult↗
PubMed1986

Verapamil and 24-hour ambulatory blood pressure monitoring in essential hypertension.

The antihypertensive effects of oral regular and slow-release verapamil, a calcium-channel blocking agent, were evaluated in 22 patients with mild to moderate hypertension (sitting diastolic blood pressure [DBP] 95 to 112 mm Hg). The dose required to control blood pressure varied from 80 to 120 mg, 3 times a day. All patients received regular verapamil for a further 3 to 4 months, when systolic blood pressure (SBP) and DBP had risen from the end of the open-label phase. During a double-blind phase patients were randomly assigned to continue the same dose of regular verapamil, 3 times a day, or an equivalent daily dose of sustained-release verapamil (240 to 360 mg once a day). Seven of the 11 patients on regular and 3 of the 11 on sustained-release verapamil were also taking diuretics. This antihypertensive program was continued for at least 4 weeks. During the efficacy period, 24-hour ambulatory blood pressure monitoring was carried out. Mean 24-hour SBP and DBP were 133 +/- 20 and 89 +/- 13 mm Hg, respectively, on regular and 131 +/- 22 and 87 +/- 12 mm Hg, respectively, on sustained-release verapamil. There were no statistically significant differences noted between the 2 groups. Mean SBP and DBP varied similarly during awake and sleep hours with both formulations of verapamil. With regular verapamil, SBP was 139 +/- 18 and 124 +/- 20 mm Hg and DBP 92 +/- 11 and 84 +/- 13 mm Hg during awake and sleep hours, respectively; with sustained release, SBP was 138 +/- 21 and 122 +/- 22 mm Hg and DBP 92 +/- 10 and 80 +/- 10 mm Hg during awake and sleep hours, respectively. Heart rate fell during the entry period and continued during the entire study period. No other adverse effects were noted during the double-blind phase. In summary, verapamil is an effective antihypertensive medication and can be administered once a day as a sustained-release preparation; it is most useful in patients in whom adrenergic blocking drugs are indicated.

Administration, Oral↗
PubMed1986

Primary carcinoma of the fallopian tube.

From 1964 through 1983, 47 patients with a mean age of 63 years underwent primary treatment of fallopian tube carcinoma. Vaginal bleeding, abdominopelvic pain or pressure, and a palpable pelvic mass (or masses) were frequent retrospective clinical associations. Survival analysis demonstrated a rapid initial rate of patient attrition with stabilization after 3 years, resulting in an overall 5-year survival rate of 41%. While independent of age, histologic grade, or original tumor size, patient longevity was significantly decreased (p less than 0.01) by the presence of disease beyond the pelvis, neoplastic cells in the peritoneal washings, and size of residual disease. Therapy consisted of primary surgical resection, usually followed by adjunctive radiotherapy or chemotherapy. Initial sites of relapse were predominantly (88%) within the intraperitoneal cavity. The study supports definitive surgical staging and tumor reduction, as well as more selective adjuvant therapy based on surgical stage and residual tumor size and location.

Adenocarcinoma↗
PubMed1986

Urinary diversion with use of ileal and sigmoid conduits.

Two hundred eighteen patients underwent urinary diversion: 156 with ileal and 62 with sigmoid conduits. There were no significant differences between the two groups regarding frequency of conduit morbidity or patient survival. The ileal conduit is preferred for urinary diversion with anterior exenteration, whereas the sigmoid conduit is preferable for urinary diversion with total exenteration.

Adolescent↗
PubMed1986

Neurotensin in diabetes and obesity.

Basal and postprandial concentrations of immunoreactive neurotensin were measured in insulin dependent diabetic patients and lean and obese noninsulin dependent diabetic patients when partially withdrawn from subcutaneous (s.c.) insulin treatment and again when near normoglycemia had been achieved from insulin infusion by an artificial endocrine pancreas (AEP). Neither basal nor postprandial neurotensin differed among the 3 groups of diabetic patients during s.c. insulin treatment nor from weight matched nondiabetic subjects. In addition, AEP resulted in no significant change in postprandial neurotensin responses. No differences in neurotensin levels were observed between lean and obese nondiabetic subjects. In contrast to observations in experimental diabetes, these observations do not support the presence of an abnormality of neurotensin in human diabetes.

Blood Glucose↗
PubMed1986

Confidence intervals following group sequential tests.

A procedure is proposed for obtaining confidence intervals for the probability of response following completion of a group sequential phase II trial. Numerical examples showed that, by ordering the sample space using the likelihood principle, we are able to shorten the length of the intervals and to obtain more accurate coverage of probability relative to previously proposed methods. The method may also be used for interval estimation following phase III trials.

Clinical Trials as Topic↗