Search PubMed⌕ Search

Biomedical subjects

D Gallagher

Publications and source records attributed to D Gallagher.

At least 127 records · Page 7Linked to original sources
PubMed1985

Developmental pattern of splenic dysfunction in sickle cell disorders.

Splenic function in sickle hemoglobinopathy syndromes was assessed to determine the developmental pattern of splenic dysfunction. Nonvisualization of the spleen using technetium-99 metastable (99mTc) spleen scans correlated strongly with pocked (vesiculated) RBCs greater than or equal to 3.5%. Cross-sectional analysis of pocked RBC data from 2,086 patients showed differences in the developmental pattern of splenic dysfunction between several disorders. In hemoglobin SS disease (sickle cell anemia) and hemoglobin S beta(0) thalassemia, splenic dysfunction (greater than or equal to 3.5% pocked RBCs) often occurred in the first 6 to 12 months of life. In hemoglobin S beta(+) thalassemia, splenic dysfunction occurred less frequently and later. Splenic dysfunction in hemoglobin SC disease (sickle cell-hemoglobin C) was intermediate. The level of pocked RBCs was inversely associated with fetal hemoglobin (P less than .007) and directly associated with age (P less than or equal to .001). These patterns of splenic dysfunction reflect the known severity of hemolysis and intravascular sickling and are consistent with the epidemiology of severe bacterial meningitis and sepsis in these diseases. Serial measurement of pocked RBCs permits determination of the onset of splenic dysfunction and the time of increased susceptibility to severe bacterial infections.

Age Factors↗
PubMed1984

Reasons for the lack of association between changes in health behavior and improved health status: an exploratory study.

Persons with arthritis who attended a 12-hour self-management course generally showed improved health behaviors and improved health status. However, no association was found between the two. We therefore interviewed 54 course participants to determine factors that were associated with positive and negative health-status outcomes. Persons having positive outcomes indicated that they had more control over their disease and had a positive emotional status. Persons with negative outcomes indicated a lack of control and generally had a negative emotional status. These differences were statistically significant.

Arthritis↗
PubMed1984

Effects of bereavement on self-perceptions of physical health in elderly widows and widowers.

Multiple indices of self-perceived physical health for 212 older widows and widowers, 2 months following the loss of their spouse, were contrasted with the responses of 162 comparison control participants for a comparable period. Although physician visits and hospitalizations were reported to be no more frequent among the bereaved, they did report significantly more recently developed or worsened illnesses, greater use of medications, and poorer health ratings in general. These differences were independent of sex and variation in socioeconomic background. Significant sex differences, although minimal, indicated poorer perceived health among women.

Aged↗
PubMedDate not supplied

Menopausal changes in body composition and energy expenditure.

Adult American women as a group tend to gain weight with age, and many women report that their weight gain started around the time of their menopause. Moreover, as women age, there are changes in body composition that include losses in bone mineral and body cell mass, and increases in total body fat, visceral fat, and extracellular fluid. It appears as if these body composition changes begin or accelerate during the menopausal years. The importance of weight gain and changes in body composition are their associations with an increased risk of developing some malignancies, cardiovascular disease, osteoporosis, and several other clinical conditions. This overview describes selected studies of menopause and aging-associated weight gain, changes in body composition, and alterations of energy expenditure in women. Gaps in the present understanding of these changes are highlighted, and an emphasis is placed on new research methodologies for investigating body composition and energy expenditure in vivo. A concluding section of the report summarizes areas in need of future investigation.

Body Composition↗
PubMedDate not supplied

MRI brain image segmentation by multi-resolution edge detection and region selection.

Combining both spatial and intensity information in image, we present an MRI brain image segmentation approach based on multi-resolution edge detection, region selection, and intensity threshold methods. The detection of white matter structure in brain is emphasized in this paper. First, a multi-resolution brain image representation and segmentation procedure based on a multi-scale image filtering method is presented. Given the nature of the structural connectivity and intensity homogeneity of brain tissues, region-based methods such as region growing and subtraction to segment the brain tissue structure from the multi-resolution images are utilized. From the segmented structure, the region-of-interest (ROI) image in the structure region is derived, and then a modified segmentation of the ROI based on an automatic threshold method using our threshold selection criterion is presented. Examples on both T1 and T2 weighted MRI brain image segmentation is presented, showing finer brain tissue structures.

Brain↗
PubMedDate not supplied

Upper extremity skeletal muscle mass: potential of measurement with single frequency bioimpedance analysis.

This study examined the potential of single frequency (50 kHz) BIA for estimation of upper extremity skeletal muscle (SM) mass. Subjects (n = 50) were weight stable adults varying in age (X +/- SD, 51.6 +/- 17 yr) and body mass index (27.2 +/- 5.9 kg/m2). Determinants of arm to arm impedance index (length L; L2/Z) were examined using multiple regression analysis. A good correlation was observed between L2/Z and arm SM estimated by dual-energy X-ray absorptiometry (r = 0.88, p < 0.001). Additional significant model covariates were arm fat mass (p < 0.05), bone mass (p < 0.01), and age (p < 0.001). These findings suggest that upper extremity SM may be rapidly and easily quantified using a simple and inexpensive BIA system combined with appropriate age-adjusted impedance prediction equations.

Absorptiometry, Photon↗
PubMedDate not supplied

Muscle distribution: variations with body weight, gender, and age.

UNLABELLED: Little is known about skeletal muscle distribution in healthy adults. Data were collected on 132 healthy, ambulatory, Caucasian women and men, aged 20-89 yr. Appendicular skeletal muscle mass multiple regression models were developed to assess the relationships between regional skeletal muscle and height, weight, age, ethnicity, and extremity lengths. RESULTS: (1) with an increase in body weight there is a greater relative increase in upper muscle distribution; (2) women have less upper muscle mass compared to men; (3) with increasing age there is a relative reduction in upper muscle distribution. The present results indicate that skeletal muscle is not a homogenous component, but has at least three independent factors, gender, weight, and age, influencing distribution.

Absorptiometry, Photon↗
PubMedDate not supplied

Lean R value for DXA two-component soft-tissue model: influence of age and tissue or organ type.

Dual-energy X-ray absorptiometry (DXA) is an important new body composition method that is based on tissue attenuation of two main photon energies. When the two photon energies pass through tissue, attenuation at the lower energy compared with that at the higher energy can expressed as a ratio (R), which is used for tissue component identification. We tested whether: (1) the R value of lean tissue is related to age, and (2) the R value of lean tissue differs between soft tissue locations. Elemental content of various tissues from the literature was used. Results show that lean R values for 40 keV and 70 keV are independent of age and tissue type.

Absorptiometry, Photon↗
PubMedDate not supplied

Memory complaint and performance in normal and depressed older adults.

The present study investigated the influence of depression on memory complaints and performance in a sample of community dwelling older adults (N = 41). Complaints were significantly more frequent in the clinically depressed subsample. However, their actual performance on tests of immediate and delayed recall did not differ significantly from the performance of nondepressed older adults. In addition, results indicated that depressives who responded favorably to a program of psychotherapy demonstrated significant reductions in levels of memory complaints at post-treatment assessment. Implications of these data for further research are discussed.

Aged↗
PubMedDate not supplied

The prognostic significance of the skeletal manifestations of acute lymphoblastic leukemia of childhood.

The variety and distribution of skeletal pathology in children with acute lymphoblastic leukemia is rarely seen in other disease states. Skeletal radiographic changes associated with and/or suggestive of acute leukemia include diffuse osteopenia, metaphyseal bands, periosteal new bone formation, geographic lytic lesions, sclerosis, mixed sclerosis/lysis, and permeative destruction. This retrospective analysis of 83 children with acute lymphoblastic leukemia suggests that children without radiographic skeletal abnormalities have an "aggressive" form of leukemia. Children with one to four lesions have an "indolent" form of leukemia that is of short duration. Children with five or more lesions have an indolent form of leukemia that is of longer duration. The longer duration of symptoms before diagnosis reduces the survival rate to that of the aggressive form of leukemia. It is therefore imperative that physicians who treat children recognize the orthopaedic/radiographic manifestations of acute leukemia (the most common pediatric malignancy) to facilitate diagnosis, and, thereby, improve survival.

Adolescent↗
PubMedDate not supplied

Extracellular water: sodium bromide dilution estimates compared with other markers in patients with acquired immunodeficiency syndrome.

Extracellular fluid and closely related extracellular water (ECW) provide information on nutritional status in health and disease. Although various methods exist for ECW determination, little is known about their comparability in patients with wasting diseases such as acquired immunodeficiency syndrome (AIDS). One practical method, the dilution of sodium bromide (NaBr), is used widely in clinical research, although its relationship to other ECW markers has not been well characterized. The present study sought to compare ECW estimates as determined by NaBr and three other methods in 11 male patients with AIDS (mean +/- SD; age, 44+/-12 years; body weight, 64.5+/-8.8 kg; and height, 172+/-4 cm). ECW volumes were determined from NaBr dilution, total body chlorine (TBCl) by delayed gamma-neutron activation analysis, total body water (TBW) by tritium dilution combined with total body potassium (TBK) by whole body 40K counting, and radioactive sulfate dilution (35SO4). All correlations between the NaBr method and other methods were statistically significant (NaBr vs TBCl [r = .91; p < .001]; vs TBW/TBK [r = .76; p < .01]; and vs 35SO4 [r = .89; p < .001]). As expected from previous studies, ECW (L) derived by NaBr provided a group mean (15.1+/-2.2 L) similar to the TBCl method (15.4+/-1.7 L; p = .32), a significantly smaller ECW than by the TBW/TBK method (18.6+/-3.4 L; p = .0004), and a significantly larger ECW than by 35SO4 method (13.3+/-3.0 L; p = .002). Estimating ECW by NaBr dilution was comparable with other research-based ECW methods and, thus, offers a practical alternative for evaluating ECW in patients with AIDS.

Acquired Immunodeficiency Syndrome↗
PubMedDate not supplied

Bioimpedance analysis: potential for measuring lower limb skeletal muscle mass.

BACKGROUND: Ambulation, balance, and lower extremity bone mass and strength are all partially dependent on lower limb skeletal muscle mass. At present, both research and clinical methods of evaluating lower limb skeletal muscle mass as a component of nutrition assessment are limited. One potential simple and inexpensive method is lower extremity bioimpedance analysis (BIA). The present study had two objectives: to examine the determinants of lower limb resistance, with the underlying hypothesis that fluid-containing muscle is the main electrical conductor of the lower limbs; and to establish if a correlation of equivalent magnitude and similar covariates is observed when height squared (H2) is used instead of lower limb length squared (L2) in multiple regression models relating resistance to independent variables. METHODS: Lower limb resistance was measured using a contact-electrode BIA system, and lower limb fat and skeletal muscle were estimated by dual-energy x-ray absorptiometry in healthy adults. A physical BIA model was developed in the form of a regression equation with path-length (as L2 and H2)-adjusted resistance as dependent variables and lower limb skeletal muscle, fat, age, and gender as potential independent variables. RESULTS: There were 94 subjects, 34 men and 60 women, with a mean (-/+SD) age of 41.5+/-17.8 years. Strong associations were observed between L2/resistance and lower limb skeletal muscle, although for both men and women, age entered into the model as a significant covariate (total R2, men = .79 and women = .72; both p < .001). Similar models were observed with H2/resistance as dependent variable. Additional analyses showed a significantly lower resistance in lower limb skeletal muscle and height-matched old vs young subjects. CONCLUSIONS: Strong associations exist between measured lower limb resistance and lower limb muscle mass, adjusting for electrical path length either by L2 or H2. These observations suggest the potential of predicting skeletal muscle using BIA-measured lower limb resistance adjusted for stature. Age is also an independent variable in lower limb resistance-skeletal muscle associations, suggesting the need to establish underlying mechanisms of age-related resistance effects and to consider subject age when developing BIA prediction models.

Absorptiometry, Photon↗