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Biomedical subjects

W A Rowe

Publications and source records attributed to W A Rowe.

15 recordsLinked to original sources
PubMed2001

Limits of body mass index to detect obesity and predict body composition.

Body mass index (BMI) is commonly used to identify obesity. In this study, we determined how accurately BMI could determine body composition and identify obese from non-obese individuals. Fat-free mass and body fat were determined with bioelectrical impedance. Adiposity was calculated as body fat per body mass and as body fat divided by body height (m2). Obesity was defined as a BMI of at least 30 kg/m2 or an amount of body fat of at least 25% of total body mass for men and at least 30% for women. Obesity as defined by percentage of body fat was always present with a BMI of at least 30 kg/m2. However, 30% of men and 46% of women with a BMI below 30 kg/m2 had obesity levels of body fat. The greatest variability in the prediction of percentage of body fat and body fat divided by height (m2) from regression equations using BMI was at a BMI below 30 kg/m2. In conclusion, using impedance-derived body-fat mass as the criterion, people with BMI of at least 30 kg/m2 are obese. However, significant numbers of people with a BMI below 30 kg/m2 are also obese and thus misclassified by BMI. Percent of body fat and body fat divided by height (m2) are predictable from BMI, but the accuracy of the prediction is lowest when the BMI is below 30 kg/m2. Therefore, measurement of body fat is a more appropriate way to assess obesity in people with a BMI below 30 kg/m2.

Adipose Tissue↗
PubMed2000

Age-related differences in the metabolic response to injury.

OBJECTIVE: To investigate the effect of age on the metabolic response to injury. METHODS: Fifty-two trauma patients meeting entrance criteria were prospectively enrolled. Patients were grouped by age: elderly, >60 years; and young, < or =60 years. After 4 days of nutrition support, physiologic and laboratory data were collected. Energy and nitrogen metabolism, and body composition were evaluated. RESULTS: Elderly patients demonstrated a reduced incidence of fever (48% vs. 77%,p = 0.027). Independent of body composition, temperature, and injury severity, oxygen consumption was 8% lower in the elderly (p = 0.0032). However, nitrogen loss and myofibrillar catabolic rate was not altered by age. Elderly subjects were more often hyperglycemic (38% vs. 0%, p < 0.0001) and azotemic (62% vs. 22%, p = 0.004), despite similar carbohydrate and protein intake. CONCLUSION: Fever is less common and oxygen consumption lower in elderly trauma patients. Postinjury myofibrillar protein catabolism and nitrogen loss are not influenced by aging. Metabolic complications of nutrition support (hyperglycemia, azotemia) are more common in elderly trauma patients.

Adult↗
PubMed1999

Bioelectrical impedance plethysmographic analysis of body composition in critically injured and healthy subjects.

BACKGROUND: Determination of body composition during critical illness is complex because of various patient-related and technical factors. Bioelectrical impedance is a promising technique for the analysis of body composition; however, its clinical utility in critically injured patients is unknown. OBJECTIVE: The purpose of this study was to compare bioelectrical impedance with metabolic activity in healthy and critically injured patients. If bioelectrical impedance accurately determines body composition during critical illness, the slope between body-composition variables and oxygen consumption would be the same in critically injured and healthy subjects. DESIGN: There is a strong linear relation between body composition and metabolic activity. In the present study, body composition (fat-free mass and body cell mass) was determined by using bioelectrical impedance and resting metabolic activity (metabolic rate and oxygen consumption) by using gas exchange analysis in a group of healthy and critically injured subjects. The relation between these variables was compared by using linear regression to a similar relation established by hydrostatic weighing in a large historical control group. RESULTS: The slope of the line relating fat-free mass to resting metabolic rate was the same in the healthy and critically ill groups (P = 0.62) and each was similar to the slope of the line for the control group. However, in 37% of the critically injured group, overhydration contributed to an increase in fat-free mass, disturbing the relation with resting metabolic rate. The slope of the line relating body cell mass to oxygen consumption in our healthy and critically ill groups was almost identical. CONCLUSION: These results support the use of bioelectrical impedance to determine body cell mass in healthy and critically ill subjects.

Adult↗
PubMed1998

The Harris-Benedict studies of human basal metabolism: history and limitations.

In the early part of the 20th century, numerous studies of human basal metabolism were conducted at the Nutrition Laboratory of the Carnegie Institution of Washington in Boston, Mass, under the direction of Francis G. Benedict. Prediction equations for basal energy expenditure (BEE) were developed from these studies. The expressed purpose of these equations was to establish normal standards to serve as a benchmark for comparison with BEE of persons with various disease states such as diabetes, thyroid, and other febrile diseases. The Harris-Benedict equations remain the most common method for calculating BEE for clinical and research purposes. The widespread use of the equations and the relative inaccessibility of the original work highlights the importance of reviewing the data from which the standards were developed. A review of the data reveals that the methods and conclusions of Harris and Benedict appear valid and reasonable, albeit not error free. All of the variables used in the equations have sound physiologic basis for use in predicting BEE. Supplemental data from the Nutrition Laboratory indicates that the original equations can be applied over a wide range of age and body types. The commonly held assumption that the Harris-Benedict equations overestimate BEE in obese persons may not be true for persons who are moderately obese.

Basal Metabolism↗
PubMed1997

The clinical usefulness of routine stacked multiplanar reconstruction in helical abdominal computed tomography.

RATIONALE AND OBJECTIVES: The authors evaluate the usefulness of stacked multiplanar reconstructions in routine, thick-section abdominal computed tomography. MATERIALS AND METHODS: Twenty-five routine, thick-section contrast abdominal CTs performed with equivalent technique were reformatted by multiplanar reconstructions in sagittal and coronal planes sequentially from side-to-side and front-to-back. The image sets were submitted, first axial images only followed by axial plus multiplanar reconstructions (MPRs), to 5 separate physician readers including 2 radiologists and 3 nonradiologists. These readers graded the visualization of a variety of normal and up to 5 pathologic lesions per patient on a scale of 1 to 5 (5 = best). RESULTS: The addition of sagittal and coronal multiplanar reconstructions significantly improved the visualization of all normal anatomic structures (mean axial only, 3.8; mean axial plus MPR, 4.1; P < 0.0001). In addition, most pathologic lesions were statistically better visualized with the addition of multiplanar reconstructions (mean axial images only, 3.9; mean axial plus MPR, 4.1; P < 0.0001). All five readers found improved visualization in nearly every category with the addition of the multiplanar reconstructions. However, in only 7% of cases, did a reviewer find new diagnostic information with the addition of MPR images. CONCLUSIONS: Stacked multiplanar reconstructions of routine, thick-section abdominal CT has clinical value in both the display of normal anatomic and pathologic lesions. Further studies, however, are required to confirm these findings before it is commonly used.

Humans↗
PubMed1995

Monolayer cell culture of freshly isolated adipocytes using extracellular basement membrane components.

Cell biological techniques requiring cells attached to surfaces, such as monolayer cell culture, microspectrofluorometry, and confocal microscopy, have not been readily available for use on adipocytes because they float and tend to lyse when attached to charged non-biological surfaces. A new method for attaching freshly isolated rodent adipocytes to thermanox plastic surfaces using Matrigel (a defined mixture of extracellular matrix components that resembles the basal lamina surrounding adipocytes in vivo) is described. The method takes advantage of an unusual physical characteristic of Matrigel, i.e., that it is a liquid at cold temperatures and a hydrated gel at higher temperatures. To attach the isolated cells, chilled thermanox plastic coverslips were coated with a thin uniform layer of ice-cold Matrigel and inverted into warm floating adipocytes. Adipocytes floated up against the liquid Matrigel and became immediately attached when the Matrigel changed to a gel in response to the warmth of the cells and media. Cell volume measurements of the attached versus freshly isolated cells indicate no significant difference in the centroid cell volume of the attached cells. This indicates that the method does not select for small or large cells. Adipocytes maintained for 6 days in culture did not display any change in their size or differentiated microscopic appearance. The relative concentrations of major proteins in silver-stained SDS-PAGE gels and several differentiation state-dependent proteins, including ATP-citrate lyase, carbonic anhydrase III (CA III), adipocyte lipid binding protein (ALBP), and pyruvate carboxylase, were examined. No significant change was observed in the relative concentrations of these proteins when the matrigel-cultured adipocytes were compared to freshly isolated cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Adipocytes↗
PubMed1994

Polarized Na+/H+ exchange function is pliable in response to transepithelial gradients of propionate.

Short-chain fatty acids are produced at high concentration in the colonic lumen and stimulate electroneutral Na+ absorption by activating apical Na+/H+ exchange in colonocytes. We used an epithelial cell line derived from a human colon carcinoma (HT29-18-C1) to study activation of apical and basolateral Na+/H+ exchange by a short-chain fatty acid, propionate. Confluent cell monolayers on membrane filters were loaded with 2',7'-bis(2-carboxyethyl)-5 (and 6)-carboxyfluorescein (a fluorescent pH indicator) and intracellular pH was monitored with a digital fluorescence imaging microscope. Cells acidified by transient exposure to NH4Cl demonstrated both apical and basolateral Na+/H+ exchange. In this condition, apical Na+/H+ exchange was 50% of the total Na+/H+ exchange activity. Similar results were obtained when cells were bilaterally perfused with apical and basolateral propionate in an isosmotic medium (130 mM propionate at each membrane surface). However, apical Na+/H+ exchange was a significantly larger fraction (76%) of the total Na+/H+ exchange activity when cells were acidified by exposure to apical propionate alone. Conversely, in cells acidified by basolateral propionate alone, apical Na+/H+ exchange was 21% of the total Na+/H+ exchange activity. The change in relative activity was observed in individual cells which expressed both apical and basolateral Na+/H+ exchange and occurred rapidly (within 7 min). In the presence of transepithelial propionate gradients, all Na(+)-dependent alkalinization was sensitive to 3 microM 5-(N-ethyl-N-isopropyl)amiloride, a potent Na+/H+ exchange inhibitor. These results suggest that transepithelial gradients of short-chain fatty acids, which occur in vivo, can cause preferential activation of apical Na+/H+ exchange.

Ammonium Chloride↗
PubMed1993

Propionate activates multiple ion transport mechanisms in the HT29-18-C1 human colon cell line.

Short-chain fatty acids (SCFAs) are the major solutes and the major anions in the colonic lumen. We studied the response of suspended HT29-18-C1 cells (an epithelial cell line derived from a human colon carcinoma) to SCFA exposure. Cellular response was evaluated by measurement of cell volume (Coulter counter), intracellular pH [pHi; measured fluorometrically with 2',7'-bis(2-carboxyethyl)-5-(6)-carboxyfluorescein (BCECF)], and intracellular Na+, K+, and Cl- content (flame photometry and chloride titrator). Exposure to 130 mM propionate in isosmotic medium causes a rapid decrease in pHi and activates pHi recovery via amiloride-sensitive Na-H exchange. In the presence of propionate, Na-H exchange also causes cell swelling to a peak volume 11% above control cells and causes a 2.8-fold increase in intracellular Na+ content. After peak swelling, a regulatory-volume decrease (RVD) significantly reduced volume and intracellular Na+ returned to baseline. Other SCFAs (acetate, butyrate, and valerate) also elicit swelling and RVD. Activation of the Na(+)-K(+)-adenosinetriphosphatase (ATPase) is required to return Na+ to normal levels and to indirectly provide ion gradients required for propionate-induced RVD, but Na(+)-K(+)-ATPase activity does not directly mediate RVD. When 1 mM 4-acetamido-4'-isothiocyanostilbene-2,2'-disulfonic acid (SITS) is added in the presence of propionate, RVD was inhibited and cell Na+ content increased. Cl- depletion inhibited propionate-induced RVD and diminished the effect of SITS.

4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfo↗
PubMed1991

Enhancement of rat intestinal calcium absorption by vanadate.

Vanadate alters intestinal transport and may have a role in regulating cell function. To determine whether it influences calcium absorption, we tested the effects of acute and chronic vanadate administration on calcium absorption using single-pass perfusion of jejunal and ileal segments of the in vivo rat intestine. Acute vanadate administration increased the lumen-to-mucosa and net fluxes of calcium in both the jejunum and ileum. The increase was largely due to an enhancement of the saturable fluxes of calcium and was observed at 10(-4) M concentration of vanadate, but not at higher or lower concentrations of the oxyanion, except at the highest concentration used, 10(-2) M, where calcium absorption was inhibited. Chronic vanadate administration caused, on the other hand, no changes in calcium absorption. We have demonstrated previously that rat intestinal (Na+ + K+)-ATPase is inhibited by vanadate, an effect that could raise cell sodium and increase the efflux of sodium across the brush border membrane. The results suggest that the vanadate enhancement of calcium absorption may be related to an increased entry of calcium into the mucosa, possibly as a result of an augmented exchange through the Na+/Ca+ antiport system. Alternatively, vanadate may influence access to a calcium channel in the mucosal membrane of the intestinal epithelium, leading to the observed increase in absorption.

Animals↗
PubMed1988

The nonspecific nature of the vanadate inhibition of rat ileal (NA,K)-ATPase.

Vanadate has been suggested as an intracellular regulator of (Na+ + K+)-ATPase. To test this hypothesis we examined the stimulatory and inhibitory effects of vanadate on 86--Rb efflux and influx (measurements of the activity of the Na-pump) in rat ileum under conditions of normal, reduced and increased (Na+ + K+)-ATPase activity. The half maximal stimulation of the Rb efflux and the half maximal inhibition of the Rb influx were not different in the three conditions tested. This suggests that vanadate does not have a regulatory effect on the activity of the Na-K-transport enzyme. The vanadate effect seem rather, to be nonspecific in terms of being unrelated, on a mole per mole basis, to the activity of the (Na+ + K+)-ATPase enzyme.

Animals↗
PubMed1987

Effect of vanadate on amino acid transport in rat jejunum.

Vanadate has been reported to inhibit (Na+ + K+)-ATPase of many cells and in some systems to stimulate adenylate cyclase. Since intestinal transport is influenced by these enzymes, we studied the effects of varying concentrations of orthovanadate (VO-4) on alanine transport in the in vitro rat jejunum. At the higher concentrations tested (10(-3) and 10(-2) M) vanadate had a ouabainlike action on alanine transport. It decreased the mucosal-to-serosal flux and the influx of alanine into the intestinal epithelium and it caused a reduction of (Na+ + K+)-ATPase activity of basolateral membranes. The relatively lower vanadate concentration of 10(-4) M increased the influx and the efflux of alanine across the mucosal border of the jejunum. The increase was associated with elevation of cyclic AMP in the intestinal mucosa. The studies suggest the presence of a dual action of vanadate on amino acid transport, a stimulatory effect at low concentration, due to increased adenylate cyclase activity, and an inhibitory effect at higher concentrations, due to a decreased activity of (Na+ + K+)-ATPase.

Adenosine Triphosphatases↗
PubMed1986

Photoaffinity labelling of a 33-35,000 dalton protein in cardiac, skeletal and smooth muscle membranes using a new 125I-labelled 1,4-dihydropyridine calcium channel antagonist.

The binding sites for Ca2+ channel antagonists were probed using Bay P 8857 [2-iodoethyl isopropyl 1,4-dihydropyridine-2,6-dimethyl-4-(3-nitrophenyl)-pyridine-3,5-dicarbox ylate] that has been radiolabelled with 125I. This drug was shown to bind with high affinity to cardiac, smooth, and skeletal muscle membranes, with a KD approximately equal to 0.3 nM. A protein of molecular weight 33-35,000 daltons was specifically and irreversibly radiolabelled after irradiation of cardiac, skeletal and aortic smooth muscle membranes, incubated with the [125I]-Bay P 8857. The peptide labelled by 1,4-dihydropyridine binding therefore appears similar in size for cardiac, skeletal, and smooth muscle. This data suggests that of the three peptide subunits which reportedly comprise the skeletal and cardiac muscle 1,4-dihydropyridine receptor complex, the 33-35,000 dalton peptide contains the dihydropyridine binding site.

Affinity Labels↗