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W P Steffee

Publications and source records attributed to W P Steffee.

10 recordsLinked to original sources
PubMed1991

Percent body fat in obese white females predicted by anthropometric measurements.

The percent body fat (PBF) and 15 anthropometric measurements were measured in 221 obese white females randomly assigned to validation and cross-validation groups. Two new anthropometric equations for the prediction of the percent of body fat were generated by multiple regression. Equation 1 includes the residual lung volume (RV) as a factor and had a correlation coefficient (r) of 0.85 and a standard error of the estimate (SEE) of 3.9%. Equation 2 does not include the RV and has an r of 0.82 and an SEE of 4.3%. Both equations were more precise than two previous widely used equations. In a subgroup of 37 subjects who underwent weight loss, equation 1 gave a more precise estimate of the change in PBF. We conclude that the new equations permit a better prediction of the PBF in obese white females.

Adipose Tissue↗
PubMed1986

Microbial growth in clinically used enteral delivery systems.

Potential contamination of enteral formulas has led to the development of policies limiting formula hangtimes. However, enteral administration bags can easily become contaminated during formula refilling. We prospectively studied enteral formula contamination when the hangtime of a prefilled 1000 ml pouch was compared with the standard 4-hour hangtime of a refilled enteral administration bag. Samples of formula collected from different locations along the enteral delivery system were cultured during 57 days of enteral hyperalimentation in 19 patients. The overall enteral formula contamination rate was 61%, where the greatest microbial growth occurred in reconstituted enteral formulas. The presence of microbial growth did not differ between canned formulas administered according to a 4-hour hangtime and the prefilled pouch. Greatest growth in all cases was at the distal tubing hub, where contamination during system manipulation or from the patient probably occurred. Use of prefilled enteral administration bags may delay formula contamination in the administration reservoir. A change in equipment design that would decrease the need to manipulate feeding sets or feeding tube connections should be further investigated.

Aged↗
PubMed1977

Protein metabolism in human neonates: nitrogen-balance studies, estimated obligatory losses of nitrogen and whole-body turnover of nitrogen.

1. Aspects of nitrogen metabolism in the human neonate were assessed in one full-term infant and six premature infants by means of nitrogen-balance measurements, estimates of obligatory nitrogen losses and determinations of whole-body nitrogen turnover. 2. Our data indicate that the mean protein requirement for maintenance is 1-1 g of protein day-1 kg-1 and that 3-8 g of protein day-1 kg-1 should be sufficient for adequate growth in healthy premature babies. 3. The mean obligatory urinary, faecal and total nitrogen losses were estimated to be 24, 106, 145 mg day-1 kg-1 respectively. These figures are compared with published values for older infants, and the possible metabolic basis for changes in nitrogen losses during growth and development is discussed. 4. Mean values for whole-body protein synthesis and breakdown were 26-3 +/- 7-0 and 23-8 +/- 7-4 g of protein day-1 kg-1 respectively. Dietary nitrogen intake accounted for 6--18% of the nitrogen flux through the metabolic pool; urea excretion accounted for 2% of the nitrogen flux. 5. The net protein gain, estimated from nitrogen-balanced data, accounted for 9-6% of total daily protein synthesis. 6. These results are discussed in relation to published estimates of whole-body protein synthesis and breakdown at various ages. Their possible significance in the assessment of a "maintenance" requirement for protein and amino acids during the period of rapid growth and development is also considered.

Body Weight↗
PubMed1976

Dietary protein intake and dynamic aspects of whole body nitrogen metabolism in adult humans.

The constant isotope-infusion method of Picou and Taylor-Roberts was used to study rates of total body protein synthesis and breakdown in adult subjects following acute changes in the level of dietary protein intake. Six healthy adults, four males and two females, were studied after adaptation to dietary protein intakes of 1.5 and 0.38 g of protein/kilogram body weight/day. Dietary periods were from 7 to 15 days duration. 15N-glycine was used as a tracer, and was administered orally for 60 hr at 3-hr intervals, or by continuous intravenous infusion for 48 hr. Results were similar for both routes of isotope administration for the comparison conducted at the higher protein intake. At the 1.5-g protein level the mean N flux was 28.2 mg nitrogen/kg/hr, with total body protein (N x 6.25) synthesis and breakdown rates being 3.0 g/kg/day and 2.7 g/kg/day, respectively. Reducing the protein intake to 0.38 g/kg/day caused an 8% decrease (p less than 0.05) in N flux, a 27% increase (p less than 0.005) in the rate of total body protein breakdown, and a 15% increase (p less than 0.05) in the rate of protein synthesis. Endogenous amino acids were reutilized more efficiently under these conditions. The findings are discussed in relation to the way in which adult subjects adapt to acute changes in dietary protein intake.

Adaptation, Physiological↗
PubMedDate not supplied

Computer optimization of enteral hyperalimentation.

A computer program has been developed to allow the generation of written orders for the logical progression of enteral hyperalimentation by the technique of continuous nasogastric infusion. Data required for entry include name, age, sex, height, usual and current weights, degree of stress, and if indicated, restrictions of nitrogen, fluids, sodium and potassium. A specific formulation may be requested, or the computer will pick a single nutrient solution or combination of two solutions that will best meet the requested constraints. Output includes entered data with English and Metric interconversion, surface area, and estimates of basal energy expenditure, protein wastage, protein and caloric requirements. If requested, daily orders are written to include a reasonable progression of infusion rates and concentrations of the solutions(s). Daily values are printed for the total amounts to be infused of fluid, calories, protein, sodium, potassium, and mOsm. The programs have been demonstrated to run in either on-line or batch mode. The system is easily accessible by physician, dietician, nurse, or other interested professionals.

Adult↗
PubMedDate not supplied

A double-blind clinical trial comparing the gastrointestinal side effects of two enteral feeding formulas.

Adequate enteral nutritional support is often limited by gastrointestinal (GI) side effects. In this pilot clinical trial we compared an enteral nutrition formula based on soy hydrolysate (study formula, SF) against a widely used intact casein formula (control formula, CF) for the incidence of GI side effects in a completely randomized double blind design. Twenty-three nonsurgical hospitalized patients requiring enteral nutritional support and free of GI symptoms were randomly assigned to receive either the CF or the SF for 6 days continuously. Both formulas were isotonic, low in residue, lactose free and isocaloric, but differed in the type and concentration of protein and the concentration of medium-chain triglycerides. After randomization both groups were comparable in demographic characteristics, and nutritional status, but there were more patients on antibiotics in the CF group. The amount of formula infused per day and the route of administration were equivalent. The number of bowel movements per day was 1.0 +/- 0.5 for the CF group and 0.6 +/- 0.3 for the SF group (p less than 0.05). The incidence of diarrhea was 10.8% days for the CF group and 6.2% for the SF group (p = NS). High gastric residuals occurred in 16.9% of days in the CF group and 3.3% in the SF group (p less than 0.05). Vomiting incidence was 10.8% in the CF group and 1.5% in the SF group (p less than 0.05). After adjustment for the use of antibiotics as a covariate, the differences in number of bowel movements, vomiting and incidence of high residuals became less significant (p less than 0.10).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗