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Biomedical subjects

M Tayback

Publications and source records attributed to M Tayback.

At least 19 recordsLinked to original sources
PubMed1998

Age-related changes in human oestrogen receptor alpha function and levels in osteoblasts.

Oestrogen receptors (ERs) are present in human osteoblasts and mediate anti-resorptive effects on bone. Human osteoblast-like cells derived from different aged healthy female donors not on hormone replacement therapy were utilized under well-defined conditions in vitro to investigate ER function and levels. Treatment with 0.1 nM oestradiol-17beta of cell strains derived from eight young women (less than 50 years of age) increased hydroxyproline levels significantly [an average (2.2+/-0.1 S.E.M.)-fold increase], whereas cells derived from nine older women (more than 50 years of age) were not significantly affected. Similarly, cell strains, derived from younger women, transfected with a consensus oestrogen-responsive element linked to chloramphenicol acetyltransferase exhibited a greater response to oestrogen than strains derived from older women. When basal ERalpha levels were measured by enzyme immunoassay and normalized on a per cell basis, osteoblast-like strains derived from younger women (n=24) had a mean value of 2.54+/-0.16 fmol of ERalpha per 10(6) cells. In contrast, strains derived from older women (n=20) had a mean value of 5.44+/-0.48 fmol of ERalpha per 10(6) cells. An age-related increase in ERalpha number was also observed in human skin-derived fibroblasts and directly in dermal biopsies from women not on hormone replacement therapy. The results demonstrate ligand concentration-dependent ERalpha induction and indicate a loss of receptor regulation and diminution of ligand-receptor signal transduction with increasing donor age.

Adolescent↗
PubMed1998

Anticoagulation for nonvalvular atrial fibrillation: effects of type of practice on physicians' self-reported behavior.

BACKGROUND: This study examines whether social and economic factors affect physician practice and attitude with regard to warfarin anticoagulation in patients with nonvalvular atrial fibrillation. METHODS: We identified physicians in Baltimore City, Baltimore County, and Prince George's County who (1) had written one or more prescriptions for a digitalis compound during the preceding year, and (2) were classified as general practitioners, family practice specialists, internists, or cardiologists. All 358 physicians fulfilling these criteria were surveyed by questionnaire. RESULTS: The overall response rate was 43%. Physicians who wrote 15% or more of their digitalis prescriptions for Medicaid patients said they used warfarin at significantly lower rates for patients with nonvalvular AF than other (66% versus 79%, P <0.01). The opposite pattern was seen with regard to aspirin. There were no significant differences in practice pattern between physicians located in urban vs. suburban counties. CONCLUSION: In our sample, self-reported anticoagulant practices for patients with nonvalvular AF were associated with the percentage of digitalis prescriptions written for Medicaid patients. In this metropolitan area, anticoagulant therapy was reportedly prescribed for approximately 75% of patients with nonvalvular atrial fibrillation.

Anticoagulants↗
PubMed1998

Low airloss hydrotherapy versus standard care for incontinent hospitalized patients.

OBJECTIVE: To determine whether low airloss hydrotherapy reduces the incidence of new skin lesions associated with incontinence in hospitalized patients and results in more rapid healing of existing pressure sores compared with standard care. To assess subjectively patient and nursing satisfaction related to using low airloss hydrotherapy beds. DESIGN: Randomized, prospective, unblinded study. SETTING: Acute and chronic hospital wards. PARTICIPANTS: A total of 116 newly admitted, incontinent, hospitalized patients with and without existing pressure sores. INTERVENTION: Low airloss hydrotherapy compared with treatment on hospital beds and mattresses ordered by the patient's attending physician. MEASUREMENTS: Incidence rates of new skin lesion development, e.g., pressure sores, candidiasis, and chemical irritation; improvement in existing pressure sore size, volume, and status; subjective assessment of patient and nursing satisfaction. RESULTS: Possible hypothermia was identified in two patients during the first week of the study, and patient and nursing dissatisfaction with low airloss hydrotherapy remained high throughout the first months of the study. Therefore, two major modifications in the initial protocol were made: (1) increased patient temperature monitoring for hypothermia was initiated in Week 2 of the study and (2) increased staff resources for in-service training on bed use began in Week 18 of the study. After the latter change, 58 subjects were randomized to low airloss hydrotherapy and 58 to standard care. Subjects were old (median age > or = 80 years), and almost all were bedbound or nonambulatory. The median (range) length of follow-up for subjects in the treatment group was significantly shorter than for those in the control group (4 (1-60) days versus 6 (1-62) days, respectively, P = .017) because there were more dropouts from the treatment group (24 (36%) of 58 versus 2 (3%) of 58, P = .0001). The major reasons dropout occurred were patient or family dissatisfaction (12 (21%)), new or worsened skin lesions thought to be related to bed use (4 (7%)), and hypothermia < 97 degrees F (4 (7%)). The total cumulative incidence of new truncal skin lesions within 9 days of enrollment was greater in the treatment than in the control group (48% versus 14%, respectively, P < 0.01). Too few patients with existing pressure sores were treated for too short a period of time to assess the effect of low airloss hydrotherapy on pressure sore healing. Because only 10 patients treated on low airloss hydrotherapy beds were able to complete satisfaction surveys meaningfully, interpretation of these data is difficult. Only nine (21%) of 44 nurses subjectively reported overall satisfaction using the low airloss hydrotherapy bed. CONCLUSIONS: This study shows the value of a rigorously designed clinically based evaluation of a new product developed for older patients. The results of the study led to re-engineering of the prototype low airloss hydrotherapy bed as well as a change in marketing strategy. Studies of products targeted to the prevention and treatment of pressure sores in older patients should be undertaken before generalized marketing begins.

Aged↗
PubMed1997

Accuracy of patient care staff in estimating and documenting meal intake of nursing home residents.

OBJECTIVES: To determine the accuracy of patient care staff estimates and documentation of food intake of residents in nursing homes. DESIGN: Prospective, observed, unblinded cohort study. SETTING: Three urban nursing home facilities. SUBJECTS: Staff estimation and documentation of 27 nursing home residents' meal intake. MEASUREMENTS: Actual amount consumed by 27 nursing home residents was ascertained by weighing food and caloric fluids on resident trays before and after one lunch time meal. Staff estimates and documentation of percent of meal consumed was compared with actual intake. RESULTS: Patient care staff estimates differed from actual intake by approximately 20%, and in most instances intake was overestimated. Almost one-third of the residents at risk for nutritional problems were not identified correctly by staff. Chart documentation of meal intake frequently did not reflect either actual amount of meal consumed or the staff's estimation of what was eaten. CONCLUSION: Study findings indicate that the present system used to document nursing home residents' intake is inadequate and that a more accurate mechanism or an entirely different process for identifying residents at risk for nutritional problems should be developed and implemented.

Aged↗
PubMed1997

Recruitment in the Trial of Nonpharmacologic Intervention in the Elderly (TONE).

OBJECTIVE: To compare the effectiveness of different approaches to participant enrollment in a behavior modification trial. DESIGN: Concurrent, prospective evaluation performed in context of recruitment for a randomized, controlled trial. SETTING: Four study centers located in Baltimore, Maryland, Memphis, Tennessee New Brunswick, New Jersey, and Winston-Salem, North Carolina. PARTICIPANTS: Men and women aged 60 to 80 years who were being treated with a prescription medication for control of hypertension. MAIN OUTCOME MEASURES: Visit counts and percent yields were assessed at each stage of the screening and randomization process. Logistic regression was used to contrast the randomization yields for different recruitment strategies and to explore the impact of sociodemographic characteristics and geographic location on recruitment yields. RESULTS: The overall randomization yields from a prescreen contact and a first screening visit to enrollment in the trial were 11% and 31%, respectively. Randomization yields varied significantly by participant age, education, and marital status. CONCLUSIONS: Our results demonstrate the feasibility of recruitment for trials of nonpharmacologic interventions in older people and suggest that mass mailing and mass media advertising campaigns provide an effective means of enrolling in such studies participants with a broad range of personal characteristics.

Advertising↗
PubMed1996

A polymorphism of a platelet glycoprotein receptor as an inherited risk factor for coronary thrombosis.

BACKGROUND: Platelet glycoprotein IIb/IIIa is a membrane receptor for fibrinogen and von Willebrand factor, and it has an important role in platelet aggregation. It is known to be involved in the pathogenesis of acute coronary syndromes. Previously, we found a high frequency of a particular polymorphism, PlA2, of the gene encoding glycoprotein IIIa in kindreds with a high prevalence of premature myocardial infarction. METHODS: To investigate the relation between the PlA2 polymorphism and acute coronary syndromes, we conducted a case-control study of 71 case patients with myocardial infarction or unstable angina and 68 inpatient controls without known heart disease. The groups were matched for age, race, and sex. We used two methods to determine the PlA genotype: reverse dot blot hybridization and allele-specific restriction digestion. RESULTS: The prevalence of PlA2 was 2.1 times higher among the case patients than among the controls (39.4 percent vs. 19.1 percent, P=0.01). In a subgroup of patients whose disease began before the age of 60 years, the prevalence of PlA2 was 50 percent, a value that was 3.6 times that among control subjects under 60 years of age (13.9 percent, P=0.002). Among subjects with the PlA2 polymorphism, the odds ratio for having a coronary event was 2.8 (95 percent confidence interval, 1.2 to 6.4). In the patients less than 60 years of age at the onset of disease, the odds ratio was 6.2 (95 percent confidence interval, 1.8 to 22.4). CONCLUSIONS: We observed a strong association between the PlA2 polymorphism of the glycoprotein IIIa gene and acute coronary thrombosis, and this association was strongest in patients who had had coronary events before the age of 60 years.

Acute Disease↗
PubMed1995

Cell proliferation of human fibroblasts and osteoblasts in osteogenesis imperfecta: influence of age.

Clinical studies indicate that as a group, osteogenesis imperfecta (OI) subjects are shorter than age- and sex-matched controls. Not only somatic growth, but also cellular growth appears to be impaired, and these may be related to defects in extracellular matrix common to this disorder. We have investigated the growth characteristics of dermal fibroblasts and trabecular osteoblasts isolated from patients with OI and control subjects of various ages. Cell growth curves and cell doubling times were determined by measuring cell number using crystal violet dye binding. Growth curves were modeled by a modified logistic function, the three parameters of which are markers for biologically relevant growth parameters: the plateau value or upper asymptote, which reflects the maximum cell density upon confluence; the maximal growth rate (microM); and the lag time. Both normal human fibroblasts and osteoblasts showed an age-dependent decrease in microM. Normal fibroblasts exhibited no age-dependence to their upper asymptote or lag time. Fibroblasts derived from patients with OI did not have significantly different upper asymptote values microM, or lag times when compared with normal fibroblasts. Normal osteoblasts had a decrease in upper asymptote, decrease in microM, but a relatively constant lag time with increasing age. In contrast, OI osteoblast microM was decreased relative to that of normal subjects. For osteoblasts from OI patients, decreased microM appeared unrelated to the age of the subject, whereas OI fibroblasts did exhibit an age-dependent decrease in microM. The percentage of collagenase-digestible protein (a measure of collagen synthesis) produced by normal human fibroblasts correlated well with microM. Treating normal human osteoblasts with the proline analogue 3,4-dehydroproline, which destabilizes collagen triple helix formation and alters collagen synthesis, secretion, and turnover, also decreased microM. A dose response to varying concentrations of 3,4-dehydroproline was observed for normal human bone cell microM. These data suggest a link between type I collagen synthesis and cellular proliferation.

Aging↗
PubMed1990

Body weight as a risk factor in the elderly.

To determine whether body weight is a risk factor for mortality among older persons, we analyzed body mass index (weight [kilogram]/height [square meter]) data for 4710 white, National Health and Nutrition Examination Survey respondents who were aged 55 to 74 years during 1971 through 1975, in relation to their survival over an average of 8.7 years of follow-up. In a multivariate analysis that controlled for elevated blood pressure, smoking, and poverty, we found no additional risk associated with weight among women and a statistically significant, but moderate, additional risk (relative risk, 1.1 to 1.2) among men in the upper decile (body mass index, greater than or equal to 30 kg/m2). In contrast, low weight (body mass index, less than 22 kg/m2) was associated with increased mortality (relative risk, 1.3 to 1.6) except for women aged 55 to 64 years. We conclude that the accepted definition of overweight (body mass index, greater than or equal to 27.8 kg/m2 [men] or greater than or equal to 27.3 kg/m2 [women]) lacks specificity and may be inappropriate for older persons who do not have weight-related medical conditions. The low-weight mortality association, consistently demonstrated, deserves serious scrutiny.

Aged↗