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D Gallagher

Publications and source records attributed to D Gallagher.

At least 73 records · Page 4Linked to original sources
PubMed1996

Total-body skeletal muscle mass: evaluation of 24-h urinary creatinine excretion by computerized axial tomography.

A classic body-composition method is estimation of total-body skeletal muscle mass (SM, in kg) from 24-h urinary creatinine excretion (in g). Two approaches of unknown validity have been used to calculate SM from creatinine: one assumes a constant ratio of SM to creatinine, the so-called creatinine equivalence (k), and that SM = k x creatinine; the other suggests a highly variable ratio of SM to creatinine and is based on regression equations of the form SM = b + a x creatinine. We explored these two extreme possibilities by measuring SM with whole-body computerized axial tomography and collecting urinary creatinine during meat-free dietary conditions in 12 healthy adult men. Prediction equations were developed in the men that fit these two models: SM = 21.8 x creatinine (SD and CV of the ratio of SM to creatinine: 1.3 kg and 6.0%, respectively) and SM = 18.9 x creatinine + 4.1 (r = 0.92, P = 2.55 x 10(-5), SEE = 1.89 kg). The validity of each model is reviewed in the context of theoretical aspects of creatine-creatinine metabolism. This first investigation of the method of measuring urinary creatinine excretion to determine SM by using modern techniques raises important practical and basic questions related to SM prediction.

Adipose Tissue↗
PubMed1996

Techniques used in the measurement of body composition: an overview with emphasis on bioelectrical impedance analysis.

The study of human body composition is now a distinct research area consisting of three interconnected parts: the five-level model and associated rules that govern the relations between components, body-composition methodology, and biological factors that influence body composition. In this overview we summarize fundamental concepts that relate to the five-level model and body-composition methods. We show how these concepts can be used to outline the essential features needed to critically evaluate the bioelectrical impedance analysis method. Body-composition research is a rapidly expanding area and in-depth systematic evaluation of new methods is a vital aspect of the field's growth.

Body Composition↗
PubMed1996

Skeletal muscle mass: evaluation of neutron activation and dual-energy X-ray absorptiometry methods.

Although skeletal muscle (SM) is a major body component, whole body measurement methods remain limited and inadequately investigated. The aim of the present study was to evaluate the Burkinshaw in vivo neutron activation analysis (IVNA)-whole body 40K-counting and dual-energy X-ray absorptiometry (DXA) methods of estimating SM by comparison to adipose tissue-free SM measured using multiscan computerized axial tomography (CT). In the Burkinshaw method the potassium-to-nitrogen ratios of SM and non-SM lean tissue are assumed constant; in the DXA method the ratio of appendicular SM to total SM is assumed constant at 0.75. Seventeen healthy men [77.5 +/- 13.8 (SD) kg body wt] and eight men with acquired immunodeficiency syndrome (AIDS; 65.5 +/- 7.6 kg) completed CT, IVNA, and DXA studies. SM measured by CT was 34.4 +/- 6.2 kg for the healthy subjects and 27.2 +/- 4.0 kg for the AIDS patients. Compared with CT, the Burkinshaw method underestimated SM by an average of 6.9 kg (20.1%, P = 0.0001) and 6.3 kg (23.2%, P = 0.01) in the healthy men and the men with AIDS, respectively. The DXA method minimally overestimated SM in both groups (2.0 kg and 5.8% in healthy men, P = 0.001; 1.4 kg and 5.1% in men with AIDS, P = 0.16). This overestimate could be explained by a higher actual than assumed ratio of DXA-measured appendicular SM to total body SM (actual = 0.79 +/- 0.05, assumed = 0.75). The current study results reveal that large errors are present in the Burkinshaw SM method and that substantial refinements in the models that form the basis of this IVNA approach are needed. The model on which the DXA-SM method is based also needs further minor refinements, but this is a promising in vivo approach because of less radiation exposure and lower cost than the IVNA and CT methods.

Acquired Immunodeficiency Syndrome↗
PubMed1996

Effects of gender, body composition, and menopause on plasma concentrations of leptin.

Circulating concentrations of leptin ([leptin]) vary directly with body mass index and percentage body fat, and may thus constitute an afferent limb of a system regulating body fatness. We tested the hypotheses that: 1) Plasma [leptin] vary more directly with absolute fat mass than with fractional body fatness per se: and 2). The relationship between fat mass and [leptin] is significantly affected by gender and by menopausal status. [Leptin] in the post-absorptive state was examined in 67 subjects (26 male, 20 premenopausal female, 21 postmenopausal females; 43 never-obese, 24 obese) at usual body weight. Body composition was determined by hydrodensitometry, and [leptin] was determined by a double antibody ELISA assay. In male and pre-menopausal female subjects, subcutaneous adipose tissue aspirations were performed for determination of adipocyte volume by the osmium fixation method, and a 3 hour oral glucose tolerance tests was performed. At usual body weight, ([leptin]) was better correlated with absolute fat mass than with body mass index (BMI) or percentage body fat. BMI and % body fat did not account for any of the variance in [leptin] beyond that attributable to FM, per se. The regression equations relating FM to [leptin] did not differ significantly between obese and never-obese subjects. [Leptin] and fasting serum insulin concentrations were significantly correlated in males only. [Leptin] was significantly higher in pre- and post-menopausal females compared to males, even when [leptin] was corrected for differences in body composition (pre-menopausal females > post-menopausal females > males). While plasma [leptin], corrected for FM, declines significantly in women post-menopause, this decline is not sufficient to account for the striking sexual dimorphism in the relationship of leptin to fat mass. This sexual dimorphism is apparently also due, in part, to a suppressive effect of circulating androgens on [leptin].

Adipose Tissue↗
PubMed1996

The spectrum of brain MR abnormalities in sickle-cell disease: a report from the Cooperative Study of Sickle Cell Disease.

PURPOSE: To define the spectrum of abnormalities in sickle-cell disease, including infarction, atrophy, and hemorrhage, that are identified by brain MR imaging. METHODS: All MR studies included T1, T2, and intermediate pulse sequences. Images were interpreted without knowledge of the clinical history or neurologic examination findings. Brain MR imaging was performed in 312 children with sickle-cell disease. RESULTS: Seventy patients (22%) had infarction/ischemia and/or atrophy, infarction/ischemia was noted in 39 children (13%) who had no history of a stroke (the "silent" group). The prevalence rates for silent lesions were 17% for sickle-cell anemia and 3% for hemoglobin sickle-cell disease. For patients with sickle-cell anemia and a history of cerebrovascular accident, infarction/ischemia lesions typically involved both cortex and deep white matter, while silent lesions usually were confined to deep white matter. Within the age range studied, the prevalence of infarction/ischemia did not increase significantly with age, although older patients with lesions had more lesions than did younger patients with lesions. CONCLUSIONS: Brain MR imaging showed infarction/ischemia in the absence of a recognized cerebrovascular accident in 13% of patients. The prevalence of these lesions did not increase significantly between the ages of 6 and 14 years, suggesting that lesions are present by age 6. However, the increase in the average number of lesions per patient with age may indicate progressive brain injury.

Adolescent↗
PubMed1995

Unexplained disturbance in body weight regulation: diagnostic outcome assessed by doubly labeled water and body composition analyses in obese patients reporting low energy intakes.

SUBJECTS: Ten patients who had long-term disturbances in body weight regulation, were referred over a 3-year period for obesity evaluation, and reported low energy intakes (< 1,200 kcal/day). OBJECTIVE: To ascertain whether these patients had a low energy expenditure and thus reduced energy requirement, and/or whether they were misreporting their energy intake. DESIGN: Comparison of outcome measures in referred patients and in obese control patients who did not report low energy intakes and disturbances in body weight regulation. MAIN OUTCOME MEASURES: Low energy expenditure was evaluated with serum thyroid hormone levels, resting metabolic rate (RMR), thermic effect of food (TEF), and total energy expenditure (TEE) by doubly labeled water technique. Misreporting of energy intake was evaluated by comparing patients' self-reported energy intake with energy intake estimated by doubly labeled water and body composition analyses over a 14-day period. STATISTICAL ANALYSES PERFORMED: Low energy expenditure was considered present in a patient if RMR or TEE was more than 15% below predicted values according to results from the control group. Patient group TEF was compared with TEF results observed in the control group. RESULTS: All patients had normal serum thyroid hormone levels. Eight patients had RMR and TEE values within 15% of predicted values and were substantially underreporting their energy intake. One patient had low TEE (-19%) and a normal RMR, a finding that implies a low level of physical activity. This patient also underreported energy intake as estimated by the doubly labeled water technique during the study (-38%). The 10th patient had a low RMR (-23.2%) and TEE (-25.0%), the mechanism of which was uncertain. This patient's reported food intake over the 14-day period was accurate but was less than her long-term intake over months or years as suggested by doubly labeled water TEE estimates. The TEF response in patients was not significantly different from that observed in the control group. CONCLUSIONS: Underreporting of energy intake from foods is a frequent finding in patients with disturbances in body weight regulation who are referred for obesity evaluation. Severe underreporting may be detectable by means of screening measures available to most dietitians. Low energy expenditure, due either to physical inactivity or to metabolic factors, is also observed. Modern evaluation methods provide new insights into patients with weight regulatory disturbances and at the same time stimulate important new research questions.

Adolescent↗
PubMed1995

The calorie: myth, measurement, and reality.

Few dietary components are surrounded by more misinformation and myths than the calorie. This confusion can be attributed in part to a lack of accurate and practical methods for assessing energy intake and thus requirements in humans over periods extending beyond several days. The availability of modern respiratory-chamber indirect calorimetry systems and results from human studies with doubly labeled water are now helping to clarify uncertainties surrounding energy requirements. We describe studies of patients with endogenous obesity as an example of how these research methods are resolving long-standing questions regarding energy requirements. The results of these investigations reveal some of the flaws in estimating energy requirements by self-report methods. Advances in accurately measuring energy expenditure are making important contributions to the study of human energy requirements and are providing new and important research opportunities.

Calorimetry↗
PubMed1995

Measurement of skeletal muscle: laboratory and epidemiological methods.

Despite skeletal muscle's central role in the pathogenesis of sarcopenia, measurement methods remain underinvestigated and inadequately validated. Our review indicates that skeletal muscle (SM) measurement methods quantify different components and properties of muscle, ranging from the atomic to whole-body levels of body composition. Laboratory methods tend to measure whole body SM (e.g., total muscle protein, muscle cell mass, and adipose tissue-free SM components) while epidemiological methods tend to measure regional muscle (e.g., anatomic SM of an extremity). Advances in computerized axial tomography and magnetic resonance imaging methods now allow accurate estimates of whole body and regional SM and promise to finally permit comprehensive in vivo studies of SM biology and methodology. These imaging methods may help to resolve many of the confusing issues that surround the investigation of this major body composition component.

Adipose Tissue↗
PubMed1995

The heart in sickle cell anemia. The Cooperative Study of Sickle Cell Disease (CSSCD).

The objective of this study was to obtain representative echocardiographic measurements of cardiac size and function in stable patients with sickle cell disease. This prospective, multicenter study utilized central reading of echocardiograms by an investigator blinded to other patient data. Stable outpatients from a balance of inner city and rural settings with SS phenotype and a broad age range were selected, because conflicting results from earlier studies were believed to be due to these patient selection criteria. Right and left ventricular dimensions and wall thickness, left atrial and aortic root dimensions, and systolic time intervals were measured. Body surface area indexed chamber dimensions and septal thickness were significantly increased from normal. Except for the right ventricle, chamber dimensions and wall thickness were inversely correlated with hemoglobin. The relationship between left ventricular dimension and hemoglobin was significantly dependent on age. Systolic time interval ratios were normal though left ventricular ejection time was prolonged. Shortening fraction was normal but velocity of circumferential fiber shortening was abnormally low. Stable patients with sickle cell disease have dilated chambers, septal hypertrophy, and normal contractility. Though left ventricular dilatation was inversely related to hemoglobin, age (duration of illness) was an important factor in that relationship. No specific cardiomyopathy was associated with sickle cell anemia.

Adolescent↗
PubMed1995

Smokers exhibit an altered Doppler analog waveform during peripheral arterial examination.

OBJECTIVE: To identify an analog waveform characteristic of smokers by Doppler sonography, which reflects their atherogenic state, and to determine if the presence of this aberrant waveform will increase the sensitivity of the ankle pressure index (API) peripheral Doppler examination. Also, to examine the relationship between pac-yr smoked and arterial compliance. DESIGN: A cross-sectional design was used to examine the diastolic component of the triphasic arterial analog waveform. A comparison between the Doppler studies of smokers and nonsmokers was constructed. SETTING: A university-based study from the Department of Applied Physiology, Teachers College, Columbia University. PARTICIPANTS: Studied were a total of 140 sedentary subjects consisting of 70 controls and 70 smokers. Control subjects were sedentary and never smoked. Each group consisted of an equal number of male and female subjects. Smoking subjects had smoked 37.8 +/- 21.4 mean pac-yr and were sedentary. No subject had hypertension, diabetes, hyperlipidemia or cardiac disease. They had no evidence of myocardial infarction, arrhythmia, aortic coarctation, cardiac valve disease or peripheral arterial disease. Anthropometric measurements and percent body fat were recorded. A predictive, oxygen-consumption, bike ergometer test was performed to determine aerobic capacity. The standard API Doppler examination and arterial diastolic flow analysis were performed with A-mode Doppler ultrasound on all subjects. MAIN OUTCOME MEASURE: The amplitude of the diastolic component of the triphasic arterial analog waveform was examined by diastolic flow analysis. This method has been shown to quantify arterial compliance, which is a correlate of arteriosclerotic disease. RESULTS: A statistically significant difference (p < .001) existed between the mean arterial compliance values of the control and smoking groups. The mean arterial compliance value for the control group was 21.3 +/- 3.7% and 4.9 +/- 4.7% for the smoking group. The mean quantity of arterial compliance in the control group was 4.3 times greater than that observed in the smoking group. A significant inverse-linear relationship was observed between pac-yr smoked and arterial compliance (p < .001). CONCLUSION: When utilizing Doppler to identify lower-extremity occlusive disease, these results demonstrate that smokers display a distinctive analog waveform. The morphology of the waveform is characterized by an attenuated diastolic component of the analog triphasic complex. This finding reflects an advanced state of arterial disease. In our study, this characteristic waveform was identified when API remained negative. When examining the results of a Doppler peripheral arterial study in a claudication patient, the identification of this waveform suggests that advanced atherogenic changes have occurred.

Adult↗
PubMed1995

With environmental control, the effects of race and sex on blood pressure regulatory mechanisms appear diminished.

To assess environmental control on autonomic parameters between race and sex, we studied cross-sectionally, 119 West Point cadets of both sexes and of African-American and Caucasian descent. Specifically, heart period variability (HPV) and baroreceptor sensitivity index (BRSI) were assessed non-invasively. All participants had lived at the Academy for at least 1 year, had similar diets, ages, fitness status, access to medical care and educational backgrounds. Familial aggregation of hypertension was 46% for African-American and 30% for Caucasian, respectively. Autonomic outflow was assessed using the magnitude of the respiratory sinus arrhythmia (RSA) during sitting, standing and augmented breathing. Autocorrelations on 64 successive heart periods provided low frequency (LF) or high frequency (HF) distributions. The ratio of LF over HF was considered representative of sympathovagal balance. Baroreceptor sensitivity (BRSI) was assessed by recording cardiac deceleration in response to a Valsalva-induced increase in BP. Analysis of variance failed to reveal significant differences in any of these BP regulatory mechanisms between any of the groups. Prior investigations failed to control for the many environmental factors mentioned above and have therefore indicated significant epidemiological differences in the occurrence of hypertension between different races. Our results strongly suggest that environmental control seems to be an important modulator in the pathogenic mosaic of autonomic derangement, and should be strongly considered in future research.

Adolescent↗
PubMed1995

Where does it hurt? An interdisciplinary approach to improving the quality of pain assessment and management in the neonatal intensive care unit.

Identifying a premature infant's response to noxious stimuli and knowing when it is appropriate to intervene are major issues for the caregiver. After completing a pilot study, the staff of a 42-bed neonatal intensive care unit targeted improved pain assessment and management for further analysis. Using a series of Plan, Do, Check, and Act cycles they designed a stepwise set of interventions that resulted in the improved assessment and management of the neonate in pain.

Academic Medical Centers↗
PubMed1994

Differences between young and old females in the five levels of body composition and their relevance to the two-compartment chemical model.

BACKGROUND: Body composition differs between young and old females, although the magnitude of these age-related changes remains uncertain. This uncertainty persists because methodology applied in earlier studies required assumptions that may be age-dependent and also because studies included young and old subjects who differed substantially in body size and health status. METHODS: To resolve these earlier concerns we examined components at the atomic, molecular, cellular, tissue-system, and whole body levels of body composition in 19 weight- and height-matched pairs of young (age 19-35 yrs) and old (age > 65 yrs) healthy White females. Isotope dilution, dual photon, whole-body counting, hydrodensitometry, and anthropometric methods were used either alone or in combination to produce multicomponent models. RESULTS: Old females had significantly more fat, greater truncal skinfolds and circumferences, and significantly less fat-free body mass (FFM), total body potassium (TBK), total body water (TBW), and bone mineral than did their young matched counterparts. Skeletal muscle mass was less in the old females, although the magnitude of the difference from young females varied between the three indices examined. The main assumptions (i.e., TBW/FFM = 0.73 kg/kg and density of FFM = 1.100 g/cc) which the widely used two-compartment TBW and hydrodensitometry methods are based on were not significantly different in young and old females. In contrast, the main assumed steady-state value for the two-compartment TBK method (TBK/FFM = 64.2 mmol/kg) was significantly lower (p < .001) in the old females. CONCLUSION: New approaches thus allow for a critical reexamination of body composition in elderly subjects, and these methods also give new insight into less complex widely used body composition techniques.

Adipose Tissue↗
PubMed1994

Undiagnosed fractures in severely injured children and young adults. Identification with technetium imaging.

A whole-body bone scan was performed to search for undetected fractures in forty-eight patients who had multiple injuries or a head injury, or both, and who were less than twenty-two years old. The study took place from January 1991 to July 1992. Radiographs had been made of all areas of suspected skeletal trauma at the time of admission. Follow-up plain radiographs were made of all areas where unexpected abnormal tracer activity was noted. Forty-two of these areas were noted in eighteen skeletally immature patients and fifty-two, in twelve skeletally mature patients. Nineteen previously unrecognized fractures were identified in the subsequent radiographic analysis. Four skeletally immature and two skeletally mature patients had an alteration in treatment on the basis of the identification of a previously undiagnosed injury. Each of these six patients had a cast applied. A fracture was identified three weeks or more after the injury in two skeletally mature patients. These fractures would have been treated (one with a cast and the other with open reduction and internal fixation) if they had been diagnosed earlier. We believe that this analysis demonstrates the usefulness of technetium radionucleotide bone-imaging, as an adjuvant to the orthopaedic examination, in the identification of undiagnosed musculoskeletal injuries in a patient who is less that twenty-two years old and who has sustained a head injury or multiple injuries, or both.

Adolescent↗