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Biomedical subjects

L A Murray

Publications and source records attributed to L A Murray.

At least 19 recordsLinked to original sources
PubMed1999

Abnormal cardiac structure and function in mice expressing nonphosphorylatable cardiac regulatory myosin light chain 2.

A role for myosin phosphorylation in modulating normal cardiac function has long been suspected, and we hypothesized that changing the phosphorylation status of a cardiac myosin light chain might alter cardiac function in the whole animal. To test this directly, transgenic mice were created in which three potentially phosphorylatable serines in the ventricular isoform of the regulatory myosin light chain were mutated to alanines. Lines were obtained in which replacement of the endogenous species in the ventricle with the nonphosphorylatable, transgenically encoded protein was essentially complete. The mice show a spectrum of cardiovascular changes. As previously observed in skeletal muscle, Ca(2+) sensitivity of force development was dependent upon the phosphorylation status of the regulatory light chain. Structural abnormalities were detected by both gross histology and transmission electron microscopic analyses. Mature animals showed both atrial hypertrophy and dilatation. Echocardiographic analysis revealed that as a result of chamber enlargement, severe tricuspid valve insufficiency resulted in a detectable regurgitation jet. We conclude that regulated phosphorylation of the regulatory myosin light chains appears to play an important role in maintaining normal cardiac function over the lifetime of the animal.

Amino Acid Sequence↗
PubMed1999

Mood congruence and depressive deficits in memory: a forced-recall analysis.

Two experiments examined the contribution of reporting biases to mood-congruent recall patterns and diminished levels of recall frequently associated with depressed mood states. In Experiment 1, participants classified as dysphoric (n = 14) or nondepressed (n = 21) on the basis of scores on the Beck Depression Inventory and the Profile of Mood States made self-referential judgements regarding a series of affectively valenced words. Subsequently they were given an unexpected forced-recall test, which encouraged guessing to meet the output requirement (i.e. 40 responses) of the test. Nondepressed subjects confidently reported more positive words than dysphoric subjects, but the latter produced significantly more correct guesses of words that were positively valenced. Similar findings were obtained in Experiment 2, in which dysphoric (n = 40) and nondepressed subjects (n = 40) performed both self-referent and orthographic judgements of affectively valenced words, followed by either a free- or forced-recall test. The findings suggest that positive and negative trait words were adequately encoded in memory, but, consistent with cognitive theories of depression, their accessibility to retrieval was differentially limited. In addition, however, the results implicate an important contribution of diminished motivation and/or conservative report criterion in the manifestation of depression-related biases and deficits in recall.

Adult↗
PubMed1999

Prescription drug coverage and spending for Medicare beneficiaries.

Outpatient prescription drug coverage is not a Medicare covered benefit. Debate continues in Congress and elsewhere on modernizing the Medicare benefit package, including proposals that would help the Nation's seniors pay for prescription drugs. Very little is known about which persons within the Medicare population have drug coverage from other sources. Using 1995 data from the Medicare Current Beneficiary Survey (MCBS), the authors present information on who has coverage by various sociodemographic categories. The data indicate higher-than-average levels of coverage for minority persons, beneficiaries eligible for Medicare because of disability, and those with higher incomes.

Adolescent↗
PubMed1998

Confirmation of identity by a metallic knee prosthesis in a severely burnt body.

Confirmation of identification of the deceased may be obtained in several ways. In this case, identification was confirmed by matching the serial numbers on a prosthetic knee joint and co-existing anatomical abnormalities with the joint serial number and X-ray reports in the hospital notes of the suspected victim.

Journal Article↗
PubMed1997

Ipodate treatment of hyperthyroidism in cats.

OBJECTIVE: To evaluate the efficacy and safety of ipodate in the treatment of hyperthyroidism in cats. DESIGN: Prospective case series. ANIMALS: 12 cats with hyperthyroidism treated at The Animal Medical Center between November 1994 and March 1996. PROCEDURE: Each cat initially received 100 mg of ipodate/d, PO. The drug's effects on clinical signs, body weight, heart rate, and serum triiodothyronine (T3) and thyroxine concentrations were evaluated 2, 4, 6, 10, and 14 weeks after initiation of treatment. A CBC and serum biochemical analyses were performed at each evaluation to monitor potential adverse effects of the drug. Dosage of ipodate was increased to 150 mg/d and then to 200 mg/d at 2-week intervals if a good clinical response was not observed. RESULTS: 8 cats responded to treatment and 4 did not. Among cats that responded, mean body weight increased and mean heart rate and serum T3 concentration decreased during the study period. Among cats that did not respond, mean body weight decreased and mean heart rate and serum T3 concentration were not significantly changed. Serum thyroxine concentration remained high in all cats. Adverse clinical signs or hematologic abnormalities attributable to ipodate treatment were not reported in any of the cats. CLINICAL IMPLICATIONS: Ipodate may be a feasible alternative to methimazole for medical treatment of hyperthyroidism in cats, particularly those that cannot tolerate methimazole and are not candidates for surgery or radiotherapy. Cats with severe hyperthyroidism are less likely to respond to ipodate than are cats with mild or moderate disease, and cats in which serum T3 concentration does not return to the reference range are unlikely to have an adequate improvement in clinical signs.

Animals↗
PubMed1996

A longitudinal study of changes in body composition and basal metabolism in physically active elderly men.

Ageing in the elderly is usually characterised by loss of fat-free mass (FFM) and reduction in basal metabolic rate (BMR). These age-related changes probably vary in rate, timing and extent between subjects in response to differences in leisure or occupational physical activity, disease and several other factors. Information on rates of change in BMR and FFM is limited by study design (most published work is cross-sectional rather than longitudinal), and possibly by methodology (use of imprecise and/or biased methods for assessment of changes in body composition). In the present study BMR and body composition were first measured in 22 physically active elderly men (mean age 62) in good health and measurements were repeated 6.5 years later. Changes in BMR, FFM and percentage body fat were small and not statistically significant over the time period (paired t, P > 0.05). The study suggests that physically active elderly men in good health in this age range can show very small age-related declines in BMR and FFM.

Aged↗
PubMed1996

Anterior chamber depth measurement in clinical practice.

This study compares the validity of anterior chamber depth estimates provided by a slit-lamp technique with those obtained from pachometry and ultrasonography. The technique provides depth estimates which are valid to within +/- 0.33 mm relative to standard pachometry, and to within +/- 0.42 mm relative to ultrasonography. The technique is simple to perform, requires no extra slit-lamp attachments, and may be carried out on any slit-lamp which has a calibrated variable length of slit.

Adult↗
PubMed1995

Reproducibility of cardiorespiratory measurements during submaximal and maximal running in children.

With the increased use of oxygen consumption measurements in clinical and sporting studies, measurement variability has become more important to both the paediatric clinician and the sports scientist. In this study we assessed the reproducibility of cardiorespiratory measurements during submaximal and maximal running in children. Ten healthy, physically active boys (mean(s.d.) age 10.7(0.71) years) performed two submaximal and two maximal running tests within a 4 week period. The submaximal protocol consisted of three 6 minute runs at 7.2, 8.0 and 8.8 km/h. Every attempt was made to minimize the sources of non-biological variability at each testing session. During submaximal exercise, oxygen consumption (VO2), heart rate (HR) and fractional utilization appeared to be the most reliable measures accounting for over two-thirds of the total variation (coefficients of reliability (CR) of 68%, 94% and 82% respectively). Ventilation (Ve) and respiratory exchange ratio (RER) proved to be only moderately reliable accounting for less than half of the total variation (CR 50% and 45% respectively). At maximal exercise, VO2, Ve and time to exhaustion were most reliable, accounting for approximately two-thirds of the total variation (CR 65%, 63% and 63% respectively). Within this test environment, a two visit submaximal assessment was capable of estimating VO2 with a standard error of +/- 1.25 ml/kg/min. Similarly, for maximal testing a two visit assessment estimated peak VO2 with a standard error of +/- 2.28 ml/kg/min. On the evidence of these results a two visit assessment for submaximal and maximal exercise testing seems adequate to estimate the stability of submaximal cardiorespiratory measures and peak VO2 in healthy, normally active boys.

Body Weight↗
PubMed1994

Measuring the body composition of elderly subjects: a comparison of methods.

There is a paucity of data on differences between methods for the assessment of body composition in elderly subjects. Studies on younger adults suggest that such differences are of some practical significance at the individual level. In the present study the following methods of estimating percentage body fatness (BF%) were compared in healthy elderly men and women (mean age 70 (SD 6) years: densitometry; skinfold thickness; total body water; bioelectrical impedance (BIA) using an age-specific predictive equation and the manufacturers' equation; body mass index (BMI). Though BF% estimates from the various methods tended to be highly correlated with those from densitometry and with each other, differences between methods at the individual level were marked. In particular, the age-specific equations based on BMI and BIA systematically overestimated BF% relative to the other methods. Biases between BF% estimates derived from densitometry, skinfolds, BIA (manufacturers' equation) and total body water were less marked, indicating little evidence of systematic differences between these methods in elderly subjects. Individual differences between methods were slightly greater than those reported in some studies of younger adults, but this may be of little practical significance, and may be considered inevitable in view of variability between and within subjects in the extent to which the underlying assumptions of these two-component methods are met in elderly subjects.

Aged↗
PubMed1988

Molecular diversity of glucose-6-phosphate dehydrogenase: rat enzyme structure identifies NH2-terminal segment, shows initiation from sites nonequivalent in different organisms, and establishes otherwise extensive sequence conservation.

The NH2-terminal region of rat liver glucose-6-phosphate dehydrogenase (EC 1.1.1.49) is shown to differ radically from a reported amino acid sequence for the fruit fly enzyme and from one for the human enzyme. The results indicate considerable differences in the translational start point. However, a close relationship with another reported sequence for the human enzyme is established, now showing agreement between an indirectly deduced and a directly analyzed NH2-terminal structure of this enzyme type. The results provide evidence of one structural motif common to mammalian species but also suggest that genetic inconstancy 5' to, or at the start of, the region coding for the enzyme protein could be a source of intra- and interspecies diversity. This is of interest in relation to the large number of genetic variants of human glucose-6-phosphate dehydrogenase.

Amino Acid Sequence↗