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Biomedical subjects

D Dunlop

Publications and source records attributed to D Dunlop.

At least 37 records · Page 2Linked to original sources
PubMed1995

Late survival risk factors for abdominal aortic aneurysm repair: experience from fourteen Department of Veterans Affairs hospitals.

BACKGROUND: This study evaluates late survival risk factors for patients who underwent elective abdominal aortic aneurysm surgical procedures performed at 14 Department of Veterans Affairs hospitals across the United States between 1985 and 1987. METHODS: Preoperative risk factors for a representative sample of 280 male veterans were obtained from an extensive Department of Veterans Affairs Office of Quality Management study and subsequent chart review. The National Death Index was used to determine survival through December 1991. RESULTS: Mortality at 30 days was 2.9%. Kaplan-Meier survival probabilities were 89% (+/- 2%) at 1 year and 64% (+/- 3%) at 5 years. Multivariate hazards models indicated significantly poorer survival for patients with age greater than 69 years, chronic obstructive pulmonary disease, cerebrovascular disease, and left ventricular hypertrophy. A history of coronary artery disease including previous myocardial infarction or bypass operation did not predict late survival for this cohort. CONCLUSIONS: Given the substantial burden of comorbidity of veterans who use Department of Veterans Affairs facilities, the overall survival experience of this all male cohort compares well with previously published series and with overall U.S. male life expectancy. The fact that a history of coronary artery disease did not predict survival for this cohort may be related to selection bias; however, a more likely explanation is the presence of unsuspected coronary disease among patients without a documented history of angina or myocardial infarction.

Age Factors↗
PubMed1995

Predictors of hand function in older persons: a two-year longitudinal analysis.

OBJECTIVE: To validate a hierarchical model of hand function in older persons, using longitudinal data. DESIGN: Longitudinal observational study (2-year data from an ongoing longitudinal study). SUBJECTS: 689 persons older than age 60, including Continuing Care Retirement Community (n = 230), homebound (n = 204), and ambulatory (n = 255) respondents. Mean age at baseline 76.6 (SD = 8.8). MEASUREMENT: Independent variables included sociodemographics, physician measures of upper joint impairment, self-reported comorbidity, arthritis pain, depression, and anxiety. The dependent variables included grip strength and a timed manual performance test. MAIN RESULTS: Using generalized estimated equations (GEE) to test our hierarchial model, we found that gender and upper extremity joint impairment were the strongest predictors of a longitudinal measure of grip strength. Grip strength, in turn, along with demographics, comorbidity, and a measure of psychological status, was significantly related to timed manual performance. CONCLUSIONS: The longitudinal analyses confirmed a previous cross-sectional finding that upper extremity joint impairment contributes significantly to reduced grip strength, which, in turn, contributes to reduced hand performance on a timed test.

Activities of Daily Living↗
PubMed1994

Impact of joint impairment on longitudinal disability in elderly persons.

Recent longitudinal data indicating that arthritis is a major contributor to disability in elderly persons are based on self-reported diagnostic information. This longitudinal study included baseline physical examinations of joints of 541 persons over age 60. Previous results from a cross-sectional multivariate model of disability in this sample found that joint impairment (and, its absence, arthritis pain) explained a significant proportion of variance in overall disability. We have retested this model using generalized estimation equations (GEE) analysis to estimate the effect of joint impairment and arthritis pain on baseline and Year 2 disability. Findings indicate that baseline joint impairment contributes substantially to longitudinal disability. If direct measures of baseline joint impairment are unavailable, concurrent self-reported arthritis pain also predicts longitudinal disability well. These findings indicate that longitudinal studies should monitor arthritis pain and that symptomatic arthritis is a risk factor for future disability.

Activities of Daily Living↗
PubMed1993

The role of glucocorticoid activity in the inheritance of hypertension: studies in the rat.

Young (3-week-old) spontaneously hypertensive rats (SHR) had significantly higher basal plasma corticosterone levels than WKY rats and maximum responses to ACTH were also higher. In isolated adrenocortical cells from these rats, corticosterone production was also more responsive to ACTH in SHR. There was no significant difference in aldosterone production. Mononuclear leucocytes from older (10-week-old) SHR had a higher affinity for dexamethasone but a smaller number of binding sites per cell. The SHR therefore has higher circulating glucocorticoid levels and the target cells have a higher apparent affinity for this agonist. However, the target cells also have a smaller binding capacity. The precise resultant effect of these changes on glucocorticoid activity will require additional studies on specific glucocorticoid-dependent variables.

Adrenocorticotropic Hormone↗
PubMed1993

Joint impairment and ambulation in the elderly.

OBJECTIVE: To test the impact of joint impairment on ambulation in the elderly, using a multivariate model. DESIGN: Cross-sectional observational study (baseline data from an ongoing longitudinal study). SUBJECTS: Five hundred thirty-two persons over age 60, including continuing care retirement community (CCRC) (n = 222), homebound (n = 63), and ambulatory (n = 247) respondents. Mean age at assessment = 76.6 (SD = 6.6). MEASUREMENT: Independent variables included sociodemographics, physician measures of lower joint impairment, an index of cormorbidities derived from physical examination or chart abstract, self-assessed arthritis pain, depression, and anxiety. The dependent variable, ambulation, was measured as walk-rate, based on the time required to walk 50 feet. MAIN RESULTS: For the total sample, 61% of the subjects were impaired in more than one lower joint group, with almost 50% of the homebound impaired in more than three joint groups. Demographics (particularly age and education) explained much of the variance in walk-rate. After controlling for demographics and membership in the groups purposely sampled (CCRC, homebound, ambulatory), lower joint impairment accounted for an additional 7% of the variance in walk-rate. Total amount of variance explained by the model was 56% (Adjusted R2 = .56). A 3-point change in lower joint impairment score, equivalent to the maximum impairment score for a single joint group, is associated with a 4-second change in the mean time required to walk 50 feet. The knee and lower spine joints contributed most to the impact of the lower joint impairment measure. CONCLUSIONS: Among the elderly, age and education are strong predictors of performance on a walk-rate test. Independent of demographics and non-musculoskeletal conditions, joint impairment is associated with diminished walking ability in this population.

Activities of Daily Living↗
PubMed1992

Extrapulmonary small cell carcinoma of bone.

Small cell carcinoma has been reported to arise in many extrathoracic sites. However, such tumours arising from bone have not been previously described. We report what we believe is the first reported case of extrapulmonary small cell carcinoma of bone. The tumour arose from the fifth dorsal vertebra in a 60 year old woman. The patient was treated with local radiotherapy and combination chemotherapy and remains in remission, 18 months after diagnosis. As such extrathoracic small cell tumours are rare, there seem to be no clear-cut guidelines for treating them, but combination chemotherapy is recommended.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1988

Botulinum toxin in ophthalmology.

Alan B. Scott selected, researched and developed Type A Botulinum toxin for clinical use in ophthalmology. This unique drug has proved invaluable for treatment of a number of conditions which are difficult to treat in ophthalmology and in a variety of other disciplines. The indications, methods and problems of its use are described and the results of treatment of 133 patients are discussed. Up to December 1986 over 13,000 patients have been treated in a multicentre international trial without significant complications.

Aged↗
PubMed1986

Propranolol pharmacokinetics during the menstrual cycle.

The pharmacokinetics of propranolol during menstruation and in the mid menstrual cycle have been studied in nine young women taking a single 80 mg tablet on each occasion. There were wide between-individual differences in the serum concentration at any given time (4-5 fold at peak concentrations) but the serum concentration time curves within individuals showed only mild variations. The differences between the average pharmacokinetic parameter estimates for the group did not differ significantly between the two periods of study.

Adolescent↗
PubMed1986

Global stereopsis in stroke patients.

Contradictory evidence has been presented in the literature on the existence of a right-hemisphere mechanism subserving global stereopsis. In the present study evoked responses to dynamic random-dot stereograms were recorded from International 10-20 scalp sites O2, P4, T6, T4 and homotopic sites over the left hemisphere. Stroke patients with unilateral lesions were selected on the basis of satisfactory performance on ocular screening tests and on clinical or objective indications that dementia was absent. Control subjects were found among the relatives of patients. The stereopsis test schedule included left, right and centre field presentations of 30 arc min, disparities. The dot density of the disparity, relative to that of the remainder of the random dot field, was manipulated to provide a full contrast stimulus and a no-contrast uniform field stimulus, thus varying the availability of monocular cues provided by the contrast factor. Latency and amplitude of the evoked potentials were computed and submitted to analyses of variance. No significant results were found which supported the proposition of a lateralized mechanism for global stereopsis. This conclusion is in conflict with the findings of some earlier reports. It is suggested that the techniques used in the earlier experiments may not have been adequate for the study of the questions involved.

Aged↗
PubMed1984

Chromatin cleavage in apoptosis: association with condensed chromatin morphology and dependence on macromolecular synthesis.

In glucocorticoid-treated rat thymocytes and the murine lymphoid cell lines L5178 and S49 the morphology of apoptosis is associated with chromatin cleavage. The cleavage is at internucleosomal sites, apparently through activation of an endogenous endonuclease. In variants of the cell lines selected for resistance to glucocorticoid, neither apoptosis nor chromatin cleavage were observed after steroid treatment, and steroid receptors were undetectable. In thymocytes, both the morphological changes of apoptosis and chromatin cleavage were inhibited by cycloheximide and actinomycin D. The calcium-magnesium ionophore A23187 induced apoptosis and chromatin cleavage in thymocytes, and these effects were also inhibited by cycloheximide. The data confirm that the condensed chromatin which characterizes apoptosis morphologically consists of endogenously digested chromatin fragments. They also provide support for the view that at least some cells enter apoptosis by a process dependent upon macromolecular synthesis.

Animals↗
PubMed1979

Compartments of protein metabolism in the developing brain.

We investigated whether the higher rate of amino acid incorporation into immature than into mature brain protein is due to (a) rapid growth, (b) a small rapidly metabolized protein pool, or (c) a higher turnover rate of most of the protein. We measured net growth and the incorporation of [14C]tyrosine or [14C]valine into brain proteins in young rats and mice. The specific activity of the free amino acid pool was kept constant in the tyrosine experiments. Incorporation of tyrosine into protein was continued for up to 30 h by which time the specific activity of protein-bound amino acid reached 1/3 of that of the free (precursor) amino acid. The growth (accretion) of brain proteins was approx. 0.635% per h in mice and rats in the 1-4 day period after birth. In previous studies we found that the turnover rate of the bulk (about 96%) of adult brain proteins is below 0.3% per h. Because of the presence of a small (about 4%) active pool the average turnover rate is 0.6% per h. The present experiments show a degradation rate of 0.7-1.1% per h in the brain proteins of the young. This high metabolic rate is not due to a small rapidly degraded fraction of protein. The very rapid protein fraction previously seen in adult rats is either very small (below 1%) or absent in the young. Thus most of the proteins in the immature brain during the rapid growth phase are formed and broken down at a rate that is approximately three times higher than that of the bulk of proteins in the adult brain. The small active protein pool in the adult on the other hand has a metabolic rate higher than that of the immature brain proteins.

Aging↗