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Biomedical subjects

S G Sheps

Publications and source records attributed to S G Sheps.

At least 37 records · Page 2Linked to original sources
PubMed1994

Short-term (six hour), ambulatory blood pressure monitoring.

The feasibility of substituting a shorter duration of ambulatory blood pressure monitoring (ABPM) for 24h ambulatory monitoring to evaluate increased office BP measurements was investigated by analysing the records of 126 normal volunteers and 168 mildly hypertensive patients receiving placebo, including 22 studied on two occasions two months apart. The value to be predicted was the long-term awake BP mean for an individual (usual BP). Among the subjects studied on two occasions, there were no systematic differences between the two occasions and there was reasonable correspondence between the hourly patterns. Estimated variance components were substituted in a formula for the standard error of prediction (SEP) of the usual awake mean BP, for various durations and frequencies of monitoring. The lower limit of the SEP was determined by the patient-by-occasion component of variance. As few as six hours of monitoring with two to three readings/hour achieved most of the gain in precision obtainable by going from single BP readings toward continuous measurement during an entire awake period. In the remaining subjects, the influence of the day rhythm of BP on short-term monitoring was examined by measuring the differences in means of 6h periods from the full awake mean BP for starting times from 7 am to 3 pm. Among normotensives and hypertensive patients with near normal office BP (< 144/< 96 mmHg), there was little difference due to starting time. There was, however, a slight positive bias in the more hypertensive subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Emerging clinical roles for ambulatory blood pressure monitoring.

Ambulatory blood pressure monitoring is becoming increasingly popular in the diagnosis and treatment of patients with hypertensive disorders. Widespread clinical use, however, has been limited by a lack of normative data and prospective, controlled clinical studies of its impact on subsequent cardiovascular morbidity and mortality. Particular applications of this technology include the investigation of white coat hypertension and correlation of the components of diurnal blood pressure variation with hypertension-associated target organ damage. Recently, interest has extended to the role of different physiologic states such as pregnancy and aging, as well as racial and other genetic differences, in the development of hypertension and susceptibility to target organ damage, and the study of hypertension associated with diabetes mellitus, renal disease, and organ transplantation. This review summarizes recent studies in these areas in addition to discussing the current clinical indications, limitations, and future research directions of ambulatory blood pressure monitoring.

Ambulatory Care↗
PubMed1993

National standard for measurement of resting and ambulatory blood pressures with automated sphygmomanometers.

The Association for the Advancement of Medical Instrumentation develops voluntary standards for medical devices so that manufacturers might provide information on their product and basic safety and performance criteria that should be considered in qualifying the instrument for clinical use. American national standards are generated through a consensus process by committees consisting of experts in research, development, and design from user, industry, and government communities. Draft standards are made available for public review and may become American national standards after review by the American National Standards Institute. The first American national standard for electronic and automated sphygmomanometers was published in monograph form in 1987. The objective of the revised 1992 standard for electronic and automated sphygmomanometers is to provide updated labeling, safety, and performance requirements that help ensure that consumers and health care professionals are supplied with safe, accurate devices for the indirect measurement of blood pressure, including ambulatory blood pressure recorders. This standard permits validation of the automatic or electronic device by comparison with either direct, intra-arterial blood pressure measurements or the noninvasive cuff/stethoscope technique, based on Korotkoff sounds identified by individuals trained in auscultation. This summary report of the 1992 American national standard for automatic sphygmomanometers provides recommendations for the methods of comparison, statistical analysis of the data, presentation of the results, and criteria for acceptability. Users, researchers, and instrument designers should refer to the American national standard monograph for detailed requirements.

Autoanalysis↗
PubMed1992

The clinical significance of nuclear DNA ploidy pattern in 184 patients with pheochromocytoma.

Flow cytometric nuclear DNA analysis was performed on paraffin-embedded tissue samples taken from 184 patients with pheochromocytoma and paraganglioma treated between 1960 and 1987. The Hedley technique was used for measurement of nuclear DNA content. Thirty-five percent of the tumors were DNA diploid, 33% showed a DNA tetraploid pattern, and 32% had DNA aneuploid pattern. Familial pheochromocytoma and associated endocrine or neoplastic disorders were more common among patients with DNA nondiploid tumors. Eighty-four percent of the tumors that invaded blood vessels and all patients with regional or distant metastases had tumors classified as DNA tetraploid or DNA aneuploid. Of 22 patients who had disease progression, 21 (95%) had tumors with abnormal DNA ploidy pattern (P less than 0.001). All 12 patients who died of cancer-related disease had abnormal DNA ploidy; none of the patients with DNA diploid tumor (n = 64) have died of pheochromocytoma (P less than 0.01). These results suggest that nuclear DNA ploidy pattern is an important and independent prognostic variable for patients with pheochromocytoma and paraganglioma.

Adrenal Gland Neoplasms↗
PubMed1992

Prognostic profile for patients with pheochromocytoma derived from clinical and pathological factors and DNA ploidy pattern.

Eighty-eight patients with pheochromocytoma and paraganglioma treated over a 28 year period (1960-1987) were studied. Based on clinical course, they were divided into three prognostic groups: benign (n = 57); multiple (n = 12); and metastatic (n = 19). Using clinical data, histopathologic findings, and tumor nuclear DNA content a prognostic profile for each group was constructed. The following variables were studied: age, familial pheochromocytoma, associated endocrine or neoplastic disorders, number and location of the lesion at diagnosis, size of the tumor, and the nuclear DNA ploidy pattern. Of these prognostic factors the most significant to predict a future malignant clinical course were large size and local tumor extension at time of surgery. Family history of pheochromocytoma, associated endocrine disorders, and young age at presentation predicted multiplicity. Old age, absence of familial pheochromocytoma or related endocrine disorders and DNA diploid tumors seem to be favorable findings. Using these variables in combination may be helpful for early identification of patients with malignant, multiple, or benign pheochromocytoma and paraganglioma.

Adrenal Gland Neoplasms↗
PubMed1991

Age-related characteristics of ambulatory blood pressure load and mean blood pressure in normotensive subjects.

Ambulatory blood pressure monitoring has become increasingly popular for diagnosing and treating hypertension. However, data from normotensive subjects are needed for interpretation of hypertensive readings. Ambulatory blood pressure was monitored in 126 normotensive subjects (age range, 20 to 84 years). Mean systolic and diastolic blood pressure and blood pressure loads (percentage of systolic readings greater than 140 mm Hg and diastolic readings greater than 90 mm Hg) were obtained and interpreted. Mean awake systolic and diastolic pressures ranged from 125 +/- 10 to 137 +/- 17 mm Hg and 70 +/- 8 to 71 +/- 9 mm Hg, respectively. The systolic and diastolic trends of subjects' blood pressures taken during office visits and the 24-hour measurements were similar. Ranges for systolic and diastolic blood pressure loads from youngest to oldest ages were 9% +/- 14% to 25% +/- 20% and 3% +/- 7% to 4% +/- 7%, respectively. A comparison of blood pressure means from our sample that were taken during office visits and blood pressure means from a 2122-patient community survey demonstrated that our sample was reflective of an unselected population.

Adult↗
PubMed1990

Antihypertensive effects of a new sustained-release formulation of nifedipine.

The blood pressure response to a new sustained-release formulation of nifedipine was evaluated in an 8-week, double-blind, placebo-controlled study. Twenty-nine patients with mild essential hypertension were randomized to receive placebo (N = 9), 30 mg nifedipine (N = 10), or 60 mg nifedipine (N = 10). During treatment, 30-mg and 60-mg doses of nifedipine administered once daily decreased office blood pressures from 137/98 +/- 8/2 mm Hg and 141/98 +/- 15/2 mm Hg at baseline, respectively, to 126/89 +/- 9/7 mm Hg and 126/86 +/- 6/7 mm Hg (P less than .005). Noninvasive automatic ambulatory blood pressure monitoring demonstrated a marginally significant (P less than .10) reduction in the mean 24-hour blood pressure of 2/6 +/- 8/8 mm Hg and 5/6 +/- 9/9 mm Hg for patients taking 30 mg and 60 mg nifedipine once daily, respectively. Diastolic blood pressure load (the percentage of ambulatory diastolic blood pressure readings greater than 90 mm Hg) during 24 hours was decreased by 41% and 35%, with 30 mg and 60 mg nifedipine administered once daily, respectively. No significant dose response to nifedipine at these dose levels was observed. Although the once-daily formulation of nifedipine achieved effective control of office blood pressure, similar control was not observed in awake and 24-hour periods in all patients.

Adult↗
PubMed1990

Office blood pressures in supine, sitting, and standing positions: correlation with ambulatory blood pressures.

The variability of casual (office) blood pressure according to position at the time of measurement was investigated in 168 untreated patients with a history of mild to moderate essential hypertension. Two measurements were made in the supine, sitting, and standing positions on each of 2 consecutive days, and 24-hour ambulatory blood pressure monitoring was performed. The mean supine, sitting, and standing blood pressures were 146 +/- 15/91 +/- 7, 144 +/- 15/96 +/- 8, and 149 +/- 17/103 +/- 7 mm Hg, respectively. Diastolic blood pressures were significantly different from each other (P less than 0.0001). Supine and sitting systolic blood pressures were not different, but they were different from standing blood pressure (P less than 0.0001). The mean of all three positions (overall blood pressure) was 146 +/- 15/96 +/- 7 mm Hg. Supine, sitting, standing, and overall diastolic blood pressure means were 90 mm Hg or more in 88, 133, 164, and 133 patients, respectively. The mean awake ambulatory and 24-hour ambulatory blood pressures were 143 +/- 16/95 +/- 7 and 138 +/- 16/92 +/- 8 mm Hg, respectively, and diastolic blood pressures were 90 mm Hg or more in 121 and 88 patients, respectively. The correlation of office blood pressure with ambulatory blood pressure varied according to office position and was 0.76 to 0.82 (P less than 0.0001) for systolic blood pressure and 0.60 to 0.69 (P less than 0.0001) for diastolic blood pressure.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Recent developments in the diagnosis and treatment of pheochromocytoma.

The investigation and management of pheochromocytoma have been of special interest at the Mayo Clinic since 1926, when Dr. C. H. Mayo successfully removed an adrenal tumor. Recent clinical developments include the detection of asymptomatic paroxysms of hypertension by 24-hour ambulatory monitoring, detailed characterization of catecholamine cardiomyopathy by echocardiography, and further experience with Carney's triad and other polyglandular and multiple neoplasia syndromes associated with pheochromocytoma. Refinement in interpretation of catecholamine measurements and the development of radionuclide scanning with m-[131I]iodobenzylguanidine, computed tomography, and magnetic resonance imaging have greatly enhanced our diagnostic acumen. Developments in antihypertensive drug therapy and chemotherapy have improved our management of cathecholamine hypersecretion and tumor growth, respectively, in inoperable patients and in the preparation of patients for anesthesia and surgical treatment. Flow cytometry to detect abnormal DNA histograms may prove particularly useful in predicting the malignant nature of the tumors.

Adrenal Gland Neoplasms↗
PubMed1990

Reproducibility of ambulatory blood pressure load.

Twenty-two hypertensive patients were monitored during two separate drug-free occasions with a Del Mar Avionics ambulatory device. Blood pressure loads (percentage of systolic and diastolic readings more than 140 and 90 mmHg, respectively) and mean BP were measured both to determine their reproducibility and to examine how they correlate with each other. The systolic and diastolic mean awake BPs for day 1 and day 2 were 140/93 mmHg and 140/91 mmHg, respectively, and BP loads were 45%/55% and 43%/54%. Moreover, mean BP loads correlated highly (r = 0.93) with mean BP values taken on the same day. Both ambulatory mean SBP and BP load were highly reproducible (r = 0.87 and 0.80, respectively, during the awake hours), and mean DBP and load were fairly reproducible (r = 0.59 and 0.39, respectively, during the awake hours). Clinically, however, both were consistent from day 1 to day 2. Mean and individual standard deviations also were reproducible for both systolic and diastolic pressures and loads.

Adult↗