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Biomedical subjects

R A Bruce

Publications and source records attributed to R A Bruce.

At least 19 recordsLinked to original sources
PubMed1992

Arthroscopic resection of glenoid labral tears in the athlete: a report of 29 cases.

This article is a retrospective review of 28 overhead-throwing and striking athletes who underwent 29 arthroscopic partial glenoid labral resections. Indications for the procedure were a sudden inability to perform because of pain and the presence of a palpable "click" on clinical examination. At a minimum of 2 years follow-up, there was a statistically significant difference in the functional outcome between patients with stable and those with unstable glenohumral joints. In those with stable joints, there was a 91% good or excellent functional outcome. In those with unstable joints, there was a 25% good functional outcome and a 75% fair or poor functional outcome. We also noted a statistically significant difference in labral tear location between the stable and unstable glenohumeral joints. Seven of eight superior labral tears were in stable shoulders. Fourteen of 19 anterior labral tears were in stable shoulders. Both posterior labral tears were in unstable glenohumeral joints. Injury of the glenoid labrum without anatomic instability was observed in 72% of patients. Arthroscopic resection of a longitudinal labral tear in a stable shoulder can relieve the patient's discomfort and allow him or her to return to athletic competition. No patient developed clinical subluxation as a result of labral debridement, nor did any patient convert from a subluxing shoulder to a dislocating shoulder following surgery. In patients with anterior instability and labral tears, labral debridement was not a successful alternative to formal stabilization.

Adult↗
PubMed1991

Ameloblastic carcinoma. Report of an aggressive case and review of the literature.

Odontogenic carcinomas of the jaws are classified as malignant ameloblastoma, ameloblastic carcinoma or primary intraosseous carcinoma. Because these lesions are extremely rare, microscopic diagnosis is difficult. An aggressive case of ameloblastic carcinoma of the mandible is presented. In spite of radical surgery and radiotherapy, the patient expired eight months following initial diagnosis. - A review of the literature seems to indicate that so called simple ameloblastomas rarely can dedifferentiate and metastasize following multiple inadequate surgical procedures. Although radical surgery is not necessary, local excision should be thorough. - Ameloblastic carcinoma and primary intraosseous carcinomas may be histogenetically similar. They are highly malignant tumours which should be treated aggressively. Metastasis is common and prognosis is poor.

Ameloblastoma↗
PubMed1989

Strategies for risk evaluation of sudden cardiac incapacitation in men in occupations affecting public safety.

Sudden cardiac incapacitation occurring during critically stressful circumstances in men engaged in a variety of occupations may compromise public safety. Since the primary cause of this incapacitation is usually heart disease, more effective medical screening has been advocated. We report the annual incidence of sudden cardiac incapacitation in four clinical groups--4105 healthy men (Group I), 537 men with atypical chest pain syndromes (Group II), 1374 hypertensive men (Group III), and 2373 men with clinically manifest coronary heart disease (Group IV)--who have been examined and tested by maximal exercise with the Bruce protocol in Seattle community practice. Five strategies for prospective risk assessment are presented in these groups, namely age alone, clinical diagnosis before testing, the combination of both parameters, exercise-enhanced risk assessment, and the exercise criteria proposed by a Task Force for Ischemic Heart Disease (Bethesda Conference XVIII, 1986). We conclude that the exercise-enhanced risk assessment is the most effective of these strategies.

Accident Prevention↗
PubMed1988

The effect of antenatal surgery on postnatal palatal growth in sheep.

It has been suggested that repair of skin and mucosal wounds carried out in animals in utero leaves little or no trace of the operative procedure when examined at birth. This study examined the palates of lambs affected surgically in utero postnatally for scarring and transverse palatal growth. Nineteen pregnant sheep were affected at 120 days gestation. Surviving lambs followed for 6 months demonstrated altered palatal morphology.

Animals↗
PubMed1988

ST segment elevation with exercise: a marker for poor ventricular function and poor prognosis. Coronary Artery Surgery Study (CASS) confirmation of Seattle Heart Watch results.

The functional and prognostic significance of exercise-induced ST elevation (by computer averaging) in ambulatory patients with coronary heart disease was recently reported for 181 patients in the Seattle Heart Watch (SHW). To further evaluate this, 3050 approximately similar patients enrolled in CASS were analyzed with respect to initial findings, survival, and incidence of secondary coronary events over the next 6 years. The ST elevation responses in CASS patients were classified by visual interpretation of 1 mm or more, whereas the SHW patients were identified by voltage greater than 0 mV. Accordingly, prevalence of exercise-induced ST elevation was lower in CASS patients, but they had greater frequencies of prior myocardial infarction and left ventricular enlargement and dysfunction. The poor survival was similar in the subgroup with ST elevation during exercise and recovery in CASS and SHW. Although not an independent predictor when invasive variables are known, ST elevation emerges as a useful predictor when exercise testing is performed before diagnostic invasive studies.

Coronary Disease↗
PubMed1987

Oral and maxillofacial surgery in China.

The primary author is a 41-year-old oral and maxillofacial surgeon on the attending staff of the Stomatology Hospital of Nanjing Medical University in Nanjing, China. He is currently a visiting scholar at the University of Michigan and has a wide variety of experience in medicine and dentistry, including 11 years of general surgery, plastic surgery, and tumor surgery training in addition to his stomatology education. His experiences during the past 20 years have prompted his American colleagues to encourage him to present his views with respect to oral and maxillofacial surgery in China today. The purpose of this article is to promote understanding among colleagues in China and in the West.

China↗
PubMed1987

Differentiation of the organic matrix in bone repair.

This study describes the sequence of production and distribution of collagen, collagen types, proteoglycans, and calcium during bone repair in rabbits utilizing histologic and biochemical techniques. Proteoglycan content peaked 11 days following surgery and total collagen peaked 19 days after surgery, after which both levels decreased. Collagen Types I and III were present in the bone defect throughout the healing process but Type II was found only in the mid stages of repair. In the surrounding external callus Types I, II, and III were present, but Type III was not noted in the later stages of healing. These results are similar to those found in studies of fracture repair and developing bone.

Animals↗
PubMed1987

Exercise-enhanced assessment of risk factors for coronary heart disease in healthy men.

Exercise-enhanced risk assessment for subsequent morbidity and mortality due to coronary heart disease in 4105 asymptomatic healthy men (mean age of 44.6 +/- 7.9 years) is reported for in Seattle community practice. Annual incidence of primary coronary events ranges from 0.22% in 1792 men (43.6%) without conventional risk factors, to 0.42% in the majority of men (55.3%) with any risk factor(s) and less than two abnormal responses to maximal exercise. Among 44 men (1.1%) at high risk defined by any conventional risk factor(s) and any two or more abnormal responses to maximal exercise, annual incidence of primary coronary events is 5.2% (P less than 0.001). Of 1718 men under 60 years of age without conventional risk factors, 117 or 6.8% who developed ischemic ST depression with maximal exercise testing are false positive responders since no coronary event occurred during the next five years.

Adult↗
PubMed1987

Health benefits of exercise in an aging society.

The effects of regular aerobic exercise are important to an aging society increasingly preoccupied with exercise. Traditionally, most attention has been directed to the relationship between a physically active life-style and cardiovascular mortality. In an aging society, however, active life expectancy and maintenance of independence may be as important as effects of regular exercise on longevity. Regular exercise results in increased maximum aerobic capacity due to peripheral changes in muscle (increased capacity for aerobic metabolism and improved substrate and oxygen extraction with a widened arteriovenous oxygen difference) and also due to cardiovascular changes with increased stroke volume and cardiac output in normal persons. "Therapeutic benefits" of conditioning probably occur at submaximal work loads common to everyday activity, when cardiac work and myocardial oxygen consumption are less for any given work load, muscles are more efficient, and relative oxygen requirements are less. Aging is associated with a linear decline in maximum aerobic capacity. The rate of decline is twofold greater when comparing sedentary with physically active middle-aged men. Thus, regular exercise could conceivably lower functional aerobic age by slowing this functional decline. Exercise, particularly excessive exercise, is also associated with serious hazards, including sudden death, nonfatal myocardial infarction, excessive fatigue, hyperthermia, and significant musculoskeletal problems. Accounts of the health effects of exercise should consider a wide range of risks and benefits, especially those related to improving function, minimizing disability, and prolonging independent living.

Aging↗
PubMed1987

Exercise-enhanced risk factors for coronary heart disease vs. age as criteria for mandatory retirement of healthy pilots.

Exercise-enhanced risk assessment for subsequent morbidity and mortality due to coronary heart disease is examined in 4105 asymptomatic healthy men of 15 to 80 years of age (mean of 44.7 years) observed in Seattle community practice. Annual incidence of primary coronary events averages 0.22% in 1792 men (43.6%) without conventional risk factors, and 0.42% in the majority of men (55.3%) with risk factor(s), but less than two abnormal responses to maximal exercise. Among 44 men (1.1%) at high risk defined by any conventional risk factor(s) and two or more abnormal responses to maximal exercise, annual incidence of primary coronary events averages 5.2% (p less than 0.001). The proportion of men of 60-64 years at low risk with a 98% 3-year survival rate is 16 times that of men of 55-59 years at high risk with a 78% survival rate in this asymptomatic population. Of 1718 men under 60 years of age and without conventional risk factors, 117 or 6.8% developed ischemic ST depression with maximal exercise testing, but none reported any coronary event during 5.6 years of follow-up surveillance.

Aerospace Medicine↗
PubMed1987

Unusual prognostic significance of exercise-induced ST elevation in coronary patients.

Follow-up surveillance of 1136 coronary patients (918 men and 218 women) observed in Seattle community practice reveals a higher incidence of subsequent myocardial infarction, cardiac arrest or cardiac death in over 4% who manifested ST elevation during maximal exercise testing and recovery. Quantitative measurements of 100-beat signal-averaged ECG responses transmitted by dataphone from 15 testing sites provide objective classification into ST depression (less than O mV) and ST elevation (greater than O mV) during exercise and five minutes of recovery. Whereas the annual incidence of CHD events in 18.3% of men with ST depression only during exercise is 2.0%/year, it is 4.1%/year in 71.6% of men with ST depression persisting into recovery and 8.2%/year with ST elevation during exercise and recovery (P less than 0.05). Even higher event rates occur with exercise of short duration and in a subgroup who had invasive studies which demonstrated at least two vessels with 70% or more stenosis and ejection fractions under 50%.

Coronary Disease↗