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Biomedical subjects

R L Kahn

Publications and source records attributed to R L Kahn.

At least 19 recordsLinked to original sources
PubMed2000

Successful aging and disease prevention.

Substantial increases in the relative and absolute number of older persons in our society pose a challenge for biology, social and behavioral science, and medicine. Successful aging is multidimensional, encompassing the avoidance of disease and disability, the maintenance of high physical and cognitive function, and sustained engagement in social and productive activities. Research has identified factors predictive of success in these critical domains. Two additional research domains, resilience and wisdom, are suggested, and a national initiative in health promotion and disease prevention is proposed.

Aging↗
PubMed1999

The future of aging.

In 1984, the John D. and Catherine T. MacArthur Foundation funded a long-term research program that brought together 16 scientists from various disciplines to study what factors contribute to successful physical and mental aging. Last year, two of those scientists published Successful Aging, in which they discuss the study's generally encouraging findings. In the sections excerpted below, they share some sometimes surprising insights into how people age in America.

Aged↗
PubMed1999

Beta-adrenergic blockers and vasovagal episodes during shoulder surgery in the sitting position under interscalene block.

UNLABELLED: Shoulder surgery is often performed with patients in the sitting position under interscalene block anesthesia. Vasovagal episodes, characterized by a sudden decrease in heart rate and/or blood pressure, have a reported incidence of 17%-24% in this setting. We performed a retrospective study to determine whether there was an association between the use of beta-adrenergic blockers and the incidence of these episodes. Of the 150 patients identified, 20 (13.3%) had a vasovagal event. Similar proportions of patients had received a beta-adrenergic blocker in the group who had a vasovagal event compared with those who did not (20% vs 18%; P = 0.95). No other differences could be identified. We conclude that vasovagal episodes occur frequently in this setting with no identifiable risk factors. Beta-adrenergic blockers were not associated retrospectively with either an increased or decreased incidence of these episodes. The most likely mechanism involves the Bezold-Jarisch reflex. IMPLICATIONS: In this retrospective study of 150 patients who underwent shoulder surgery in the sitting position under interscalene block, we found a 13% incidence of vasovagal episodes. Unlike a previous study, this was not affected by the use of beta-blockers. A randomized, prospective study is necessary to clarify this issue.

Adrenergic beta-Antagonists↗
PubMed1998

The use of metoprolol and glycopyrrolate to prevent hypotensive/bradycardic events during shoulder arthroscopy in the sitting position under interscalene block.

UNLABELLED: Sudden profound hypotensive and/or bradycardic events (HBE) have been reported in >20% of patients undergoing shoulder arthroscopy in the sitting position under interscalene block anesthesia. Retrospective studies suggest that the administration of beta-blockers is safe and may decrease the incidence of these episodes. We performed a randomized, prospective study to evaluate prophylaxis of these events. One hundred fifty patients were randomized to one of three groups (placebo; prophylactic metoprolol to achieve a heart rate <60 bpm or a maximal dose of 10 mg; or prophylactic glycopyrrolate to achieve a heart rate >100 bpm or a maximal dose of 6 microg/kg) immediately after the administration of the interscalene block. Blood pressure control was achieved with IV enalaprilat as needed. The incidence of HBE was 28% in the placebo group versus 5% in the metoprolol group (P = 0.004). The rate of 22% in the glycopyrrolate group was not significantly different from placebo. Preoperative heart rate and arterial blood pressure, intraoperative sedation score, IV fluids, and enalaprilat use were similar in those patients who had a HBE compared with those who did not. Many aspects of this clinical setting are similar to tilttable testing for patients with recurrent vasovagal syncope, in which beta-adrenergic blockade with metoprolol has also been shown to be effective. We conclude that the Bezold-Jarisch reflex is the most likely mechanism for these events. IMPLICATIONS: Episodes of acute hypotension and bradycardia occur during shoulder arthroscopy in the sitting position under interscalene block. In this study, we demonstrate that metoprolol, but not glycopyrrolate, markedly decreases the incidence of these episodes when given prophylactically immediately after the administration of the block.

Adrenergic beta-Antagonists↗
PubMed1997

Successful aging.

Substantial increases in the relative and absolute number of older persons in our society pose a challenge for biology, social and behavioral science, and medicine. Successful aging is multidimensional, encompassing the avoidance of disease and disability, the maintenance of high physical and cognitive function, and sustained engagement in social and productive activities. Research has identified factors predictive of success in these critical domains. The stage is set for intervention studies to enhance the proportion of our population aging successfully.

Activities of Daily Living↗
PubMed1994

Socioeconomic status and health. The challenge of the gradient.

Socioeconomic status (SES) is consistently associated with health outcomes, yet little is known about the psychosocial and behavioral mechanisms that might explain this association. Researchers usually control for SES rather than examine it. When it is studied, only effects of lower, poverty-level SES are generally examined. However, there is evidence of a graded association with health at all levels of SES, an observation that requires new thought about domains through which SES may exert its health effects. Variables are highlighted that show a graded relationship with both SES and health to provide examples of possible pathways between SES and health end points. Examples are also given of new analytic approaches that can better illuminate the complexities of the SES-health gradient.

Health Behavior↗
PubMed1993

Supraventricular tachyarrhythmias during total joint arthroplasty. Incidence and risk.

Perioperative supraventricular tachyarrhythmias (AF/SVT) have been long recognized as a complication after major surgery, but little is known about the incidence after major nonthoracic surgery. One thousand two hundred ten consecutive patients undergoing total hip or knee arthroplasty were studied to determine the incidence of new onset AF/SVT. Information on preoperative medical history and laboratory tests were collected in a subset of 583 patients, and analyzed using logistic regression and linear analysis to determine risk. Ninety-four-and-one-half percent of patients received an epidural anesthetic, 4.1% had general anesthesia and 1.3% had spinal anesthesia. New onset AF/SVT was found in 38 of 1210 patients, representing an incidence of 3.1%. In the subset of 583 patients, the incidence was 4.8%. The only variables found to be independently associated with the perioperative development of AF/SVT were a history of atrial fibrillation, increasing age, left anterior hemi-block, and atrial premature depolarizations on the preoperative electrocardiogram. In those patients 60 years of age or older with one or more positive risk factors (13% of the study population), the incidence was 18.2%. In those patients less than 60 years of age with none of the identified risks, the incidence was 1.9%.

Adult↗
PubMed1991

Indirect inhibition of polymerization of a polyvinyl siloxane impression material: a case report.

The inhibition of polymerization of polyvinyl siloxane impression materials by direct contact with latex gloves has been well documented. Indirect intraoral inhibition of polymerization that results from contact of oral tissues with latex gloves during tooth preparation and gingival retraction procedures has been reported. This case report illustrates the problems that can occur when the dentist used polyvinyl siloxane impression materials while wearing latex gloves. In the reported case, the inhibition is severe and obvious; in most situations the inhibition of polymerization is more subtle and is frequently undetected. Clinicians must be aware of this potential problem and the solution to it.

Dental Impression Materials↗
PubMed1989

Age differences in productive activities.

Age differences in productive contributions through both paid and unpaid work are examined in commensurate terms. Data are from a nationwide household survey of 3,617 adults age 25 and older conducted in 1986. Older Americans participate in many unpaid productive activities at levels that are comparable to those reached by middle-aged and younger Americans; these activities include volunteer work in organizations, informal help to others, maintenance and repair of their home and possessions, and housework. Relatively few older Americans spend any time participating in paid work and unpaid rearing of children. Largely because of the cessation of paid work and child care, older Americans spend less time overall in productive activities. Women and men spend about equal time in productive activities, but women spend more of it in unpaid work and less of it in paid work. The difficulties with using paid work as the major indicator for describing productivity across the life span are discussed.

Activities of Daily Living↗
PubMed1987

Human aging: usual and successful.

Research in aging has emphasized average age-related losses and neglected the substantial heterogeneity of older persons. The effects of the aging process itself have been exaggerated, and the modifying effects of diet, exercise, personal habits, and psychosocial factors underestimated. Within the category of normal aging, a distinction can be made between usual aging, in which extrinsic factors heighten the effects of aging alone, and successful aging, in which extrinsic factors play a neutral or positive role. Research on the risks associated with usual aging and strategies to modify them should help elucidate how a transition from usual to successful aging can be facilitated.

Aged↗
PubMed1984

Productive behavior through the life course: an essay on the quality of life.

Present patterns of productive activity are neither well recognized, optimal for society, nor in accordance with individual preference. Although a great deal of attention has been given to meeting people's needs for income, medical care, and other services, the quality of their lives must also be defined by what they do for themselves and for others. In discovering present patterns of productive activity throughout the life course and optimizing those patterns, we will raise the quality of American life. To accomplish this task, two great changes are needed: we must recognize the full range of productive activities throughout the life course and give people the opportunity to modify the allocation of paid employment.

Employment↗
PubMed1978

Adaptational factors in memory function in the aged.

Memory function in the aged is described as due to the interaction of a number of variables in addition to physiology, including affective state and environmental conditions. Depression can cause a series of behavioral patterns ranging from exaggeration of memory complaint, to simulation of organic dysfunction, to "pseudodementia" in which there is production of an actual organic mental syndrome. Stress and noxious environmental conditions also contribute to cognitive dysfunction. Custodial care is singled out as especially harmful, producing a form of "excess disability" termed "unorientation" in which apparently impaired memory results from an apathetic, withdrawn reaction to the environment. All these adaptational patterns are subject to prevention, modification, and in some cases, reversal.

Adaptation, Psychological↗
PubMed1978

Brain function, intellectual impairment and education in the aged.

In assessing behavioral problems of the elderly there is a need for procedures which reliably indicate the presence and extent of impaired brain function. In this study, the relation of two mental status measures [the Mental Status Questionnaire (MSQ) and the Face-Hand test] to intellectual performance and education was evaluated. The sample consisted of 153 consecutive inpatients and outpatients referred to a gerontology clinic. Intellectual performance was assessed with 8 tests of learning and memory, such as Paired Associates and Babcock Story Recall. The findings indicate that positive ratings for impaired brain function on either mental status test were related to lower intellectual performance at each of three levels of education - grade school, high school, and college. Subjects with more education and mental status scores indicating mild impairment performed better on intellectual tests than did less educated persons with no brain dysfunction, but they showed significant deficits compared to other subjects with similar education and intact brain function. Larger intellectual deficits were found when the patient made more test errors and when both tests gave positive ratings. These results confirm the importance of the MSQ and Face-Hand tests as screening devices for the intellectual deficits associated with impaired brain function in a clinically heterogeneous population.

Aged↗