In vivo measurement of total body chlorine using the 8.57 MeV prompt de-excitation following thermal neutron capture.

Prompt gamma neutron activation analysis with 238Pu/Be sources is used to measure total body chlorine (TBCl) in vivo following the reaction 35Cl(n, gamma)36Cl. The chlorine de-excitation at 8.57 MeV is used for calibration of the system for TBCl. Body hydrogen is used as an internal standard and TBCl is derived from the gamma-ray counts ratio of chlorine to hydrogen. The precision of the method, determined from replicate scans of a Bush-type phantom, is 4.9% (CV). To assess accuracy an anthropomorphic phantom consisting of minced meat was constructed. Replicate scans of this phantom yielded a mean total chlorine which was not significantly different from the chemical analysis value. The subject dose equivalent for the activation measurement is less than 0.3 mSv. Mean TBCl values for 63 male and 107 female healthy volunteers were in broad agreement with predicted amounts based on multiple regression equations developed at other centres from measurements using the delayed gamma approach. Good agreement was observed in 76 volunteers between total body water (TBW) measured by tritium dilution, after correction for non-aqueous hydrogen exchange, and TBW derived from the sum of extracellular water and intracellular water as measured by TBCl and total body potassium (TBK), respectively.

Blood selenium values in an adult Auckland population group.

New Zealand top soils are low in selenium with some regional variation. Grain and cereal products are the main source of dietary selenium intake but in New Zealand their content is low due to widespread top soil deficiency. Whole blood levels reported from Oago, 68 +/- 13ng/ml, are a half to one-third of those in North America and also lower than in Auckland residents, 79 +/- 15.7ng/ml. The variation between New Zealanders is due to regional differences in top soil levels and grass content affecting secondary selenium sources such as sheep meat and beef. Regular consumption of selenium rich chicken and fish is associated with a significant increase above average values, but age, sex, smoking, alcohol and the use of oral contraceptives, are unimportant factors.

Wound healing response in surgical patients: recent food intake is more important than nutritional status.

We have recently found that an impairment of the wound healing response (WHR) occurs in surgical patients with protein-energy malnutrition before there are any measurable changes in body fat and protein stores. The hypothesis of this study was that the patients' recent food intake is more important in determining the WHR than the patients' overall nutritional status. We have measured the recent food intake (by dietary recall), the WHR (by hydroxyproline accumulation in subcutaneous GORE-TEX implants), the pre-operative weight loss (per cent), and body fat and protein stores (by in vivo neutron activation analysis) in 83 patients awaiting a major elective gastrointestinal resection, and divided them into two groups: adequate recent food intake (n = 59) and inadequate recent food intake (n = 24). There was no significant difference between these two groups for age, sex, diagnosis, surgical procedure, weight loss (per cent), or the amount of body fat and protein stores but there was a significant difference in the WHR (1.81 +/- 0.16 s.e.m. versus 1.04 +/- 0.22 s.e.m. nmol hydroxyproline/mg GORE-TEX, P less than 0.005). These results show that pre-operative food intake has a greater influence over the wound healing response than absolute losses of protein and fat from body stores and they suggest that the maintenance of a normal food intake up until the time of surgery is of importance in preventing an impairment of the wound healing response.

Comparison of relative risks of urinary stone formation after surgery for ulcerative colitis: conventional ileostomy vs. J-pouch. A comparative study.

PURPOSE: Urinary stone formation is a widely recognized complication o f inflammatory bowel disease and the surgical management of these conditions. Previously the fecal volume and chemistry after restorative proctocolectomy with J-pouch were found to be similar to conventional panproctocolectomy with permanent ileostomy. The purpose of this study was to investigate whether the relative risks of urinary stone formation were less following J-pouch than following conventional ileostomy. METHODS: The risk of urinary stone formation was determined from the chemical composition of two consecutive 24-hour urine samples in 13 patients with well-functioning ileostomies, 15 patients with well-functioning J-pouches, and 17 control volunteers. RESULTS: Compared with controls, ileostomy and J-pouch patients had significantly lowered urinary volumes and pH, higher concentrations of calcium and oxalate, and an increased risk of forming uric acid stones. In addition there was an increased risk of forming calcium stones in the conventional ileostomy group. This risk was found not to be present in the J-pouch group. CONCLUSIONS: The risks of forming uric acid stones are high for both ileostomy and J-pouch patients, but our results suggest that there will be a reduction in calcium stone formation after J-pouch.

Metabolism of body water and electrolytes after surgery for ulcerative colitis: conventional ileostomy versus J pouch.

Some authorities believe that patients with conventional ileostomies are chronically water and salt depleted but there are no data on the metabolism of body water and electrolytes after ileoanal J pouch. To clarify the situation we studied the body composition of 14 patients with well functioning ileostomies and 20 patients with well functioning J pouches. Both groups were compared with two closely matched control groups. Body weight, total body fat, fat-free mass, total body water and extracellular water were measured by neutron activation analysis, tritiated water and bromide dilution respectively; 24-h collections of urine and stool were analysed for volume and electrolyte content. The results show that the body content of water and extracellular fluid in ileostomy patients and J pouch patients is normal. The faecal volume and chemistry is similar in both groups resulting in a similar and significant degree of urinary sodium retention.

Body composition of two human cadavers by neutron activation and chemical analysis.

In vivo neutron activation analysis (NAA) is currently used to measure body composition in metabolic and nutritional studies in many clinical situations, but has not previously been validated by comparison with chemical analysis of human cadavers. Total body nitrogen (TBN) and chlorine (TBCl) were measured in two human cadavers by NAA before homogenization and chemical analysis (CHEM) after (cadaver 1: TBN, 1.47 NAA, 1.51 CHEM; TBCl, 0.144 NAA, 0.147 CHEM; cadaver 2: TBN, 0.576 NAA, 0.572 CHEM; TBCl, 0.0227 NAA, 0.0250 CHEM). The homogenates were also analyzed by NAA, and no significant differences were found, indicating that the effects of elemental inhomogeneity on the measurement of TBN and TBCl are insignificant. Total body water, fat, protein, minerals, and carbohydrates were measured chemically for each cadaver and compared with estimates for these compartments obtained from a body composition model, which when used in vivo involves NAA and tritium dilution. The agreement found justifies the use of the model for the measurement of changes in total body protein, water, and fat in sequential studies in groups of patients.

New and simple equations to estimate the energy and fat contents and energy density of humans in sickness and health.

Two formulas were derived to estimate the energy content of the human body which use only body mass, total body water by 3H2O dilution space and body minerals assessed by anthropometry. The formulas were tested in a body composition database of 561 patients and 151 normal volunteers using established metabolizable energy values for protein, fat and glycogen. Total body protein was determined by in vivo neutron activation analysis (IVNAA), body water by dilution of tritium and body minerals from skeletal frame size. Body glycogen was assumed to be 14.6% of the mineral component. Body fat was obtained by difference, body mass less the sum of water, protein, minerals and glycogen. The standard deviation in the estimate of body energy content was 30 MJ or 4.1% of the energy content of reference man. Two formulas for body energy content were derived by regression with body mass, total body water and body minerals or height. Two formulas for energy density and formulas for percentage body fat were similarly derived.