Body composition measurements in normal man: the potassium, sodium, sulfate and tritium spaces in 58 adults

The aqueous phase of total body composition varies with sex, and changes with age, necessitating age, sex and method-specific normal values. Consensus has developed for the methods most suited to clinical studies. 3H20 for water, 35SO4 for ECW, 24Na for NAc, and 40K for body potassium were used in 58 normal volunteers aged 19-80, 30 men and 28 women. This report shows significant age regressions in both sexes for total body water and intracellular water, and for both Na and K when referenced to body water. Combination of these findings with the highly age related decrease in total body potassium confirms previous studies that body cell mass decreases with age. Intracellular K+ and Na+ at the zero age intercept are 130 and 14.5 for males, and 124 and 24mEq/1 for females respectively. Secular decrease in K+ and increase in Na+ concentrations in the average cell are suggested although not established. Values for normal body composition, in subjects healthy by all available criteria are in some instances age and sex dependent, but in all parameters except fat show wide normal range (SD = 7% of mean) which derive more from biological variation than from limitations of measurement precision. However, use of body water rather than weight succeeds in narrowing this wide range, and is a more logical denominator which is readily subject to accurate measurement. In serial studies of the same subject, significant changes can be measured which are well within the normal range.

A possible low intracellular potassium in obesity

In comparison with lean marathon runners whose fat content was 15%, obese subjects with a fat content of 55% showed a 36% reduction in intracellular potassium. It is hypothesized that as much as 60% of this decrease may have been due to the lower proportion of muscle (which has the highest intracellular potassium of any tissue) in the fat free mass of very obese subjects. The remainder of the decrease seems to have been a measurement artefact owing to self-absorption of gamma rays by adipose tissue, most of which is distributed over potassium rich lean tissue. The low intracellular potassium values found in obesity should not be interpreted as necessarily signifying potassium deficiency.

Combined effects of alcohol and lithium on body composition in the rat model

Alcohol markedly enhances Li+ retention in blood and muscle in rats taking Li and alcohol. The marked enlargement of the exchangeable Na+ space which occurs with alcohol alone, Li+ alone, and to an even greater extent with combined therapy, results from extensive mobilization of "bound" bone sodium, which is transferred to intracellular sites, demonstrably in skeletal muscle, and presumably in other cells. This 87% increase in measured intracellular Na+, and concomitant decrease in K+, would be predicted to produce profound effects on the intracellular ionic milieu, and on membrane function. Lithium is associated with a decrease in food and fluid intake, and this effect is enhanced by alcohol. However the decrease in intake did not result in nutritionally significant deficits in either group, and therefore the observed abnormalities in body composition did not result from caloric, protein, K, Na, or Ca deficiency.

Metabolism of calf trabecular (reticular) meshwork

It has been found that calf eyes are an excellent source of trabecular meshwork tissue for biochemical studies. Homogenates of pooled meshwork were centrifuged at 27K X g and 1.5K X g. The high-speed supernatants produced lactate at 0.35 mumole/min/gm tissue in the presence of hexokinase-saturating concentrations of glucose (10 mM) at pH 7. The optimum pH was 7.6. In the absence of ammonia, lactate could be produced from fructose 1,6-diphosphate but not from glucose or glucose 6-phosphate. The optimum ammonia concentration was 1 to 2 mM. Lactate was produced at an even greater rate from fructose, but only poorly from sorbitol or galactose (all at 10 mM). The activity of hexokinase, glucose 6-phosphate dehydrogenase and UDPG dehydrogenase was measured. Fructokinase could not be detected. The low-speed supernatant readily oxidized succinate, malate, and glutamate at about 0.012 muAtO/min/gm tissue. The oxidative rate in vivo is estimated to be about one third of this. These results demonstrate that knowledge of the normal metabolism of calf trabecular meshwork may be obtained with relative ease, with possible important implications for understanding the disease of glaucoma.

Effect on body water of running 10 miles

Despite a 2.3% weight loss in 10 men who ran 10 miles, extracellular water (ECW) increased by 3.5%. Total body water (TBW) measured as tritium space increased by 2.4%, and intracellular water (ICW), inferred as the difference between TBW and ECW, increased by 1.8%. The increase in tritium space probably represents increased nonaqueous hydrogen exchange in the postexercise period ond casts doubt on the validity of TBW and ICW when measured immediately after exercise.

Humoral and cellular immune responses in Aspergillus fumigatus pulmonary disease

This study was designed to evaluate immunologic differences between aspergilloma (A) and allergic bronchopulmonary aspergillosis (ABPA), comparing the results to atopic and nonatopic control subjects. Humoral studies included skin tests with common inhalant antigens and Aspergillus fumigatus. Total and specific IgE and other immunologlobulin levels and serum precipitins were evaluated against A. fumigatus. Cellular immunity was studied with routine skin testing and phytohemaqglutinin-induced lymphocyte blast transformation. Antigen-induced blast transformation was also carried out with the use of serial dilutions of A. fumigatus. All patients with ABPA were atopic and had marked elevations of IgE. None of the patients were atopic and they had normal IgE levels. Immediate and late skin reactivity to A. fumigatus was low in control and A groups but high in 2 patients with ABPA. IgG antibody against A. fumigatus was generally greater in the ABPA group. Both ABPA and A had serum precipitating antibody against A. fumigatus. The atopic controls had elevated IgE levels and immediate skin test reactivity to A. fumigatus, and one also had weak serum precipitins against A. fumigatus. IgE antibody against A. fumigatus was generally higher in ABPA than A. ABPA and A patients had elevated stimulation indices (SI) to A. fumigatus. No stimulation could be detected with cells from control subjects. This study indicates that both T and B cell sensitization may play a role in the development of or as a response to aspergillus-related pulmonary disease.

Extracellular water measurements: organ tracer kinetics of bromide and sucrose in rats and man

Bromide and sucrose distributions were measured as functions of time after tracer injection into 14 rat organs that accounted for 93% of body wt, with the goal of evaluating the use of bromide and sucrose as tracers for the extracellular water volume (ECW). The tracers, Na, 82Br, 125I-labeled human serum albumin, [14C]sucrose, and 3H2O, were used to calculate bromide and sucrose content in red cells, plasma, and 13 blood-free organs. Selective concentration of Br- occurs in RBC, stomach, and skin, accounting in part for the discrepancy between the Br- space and the smaller ECW volume as derived from other methods. Sucrose is rapidly metabolized in the rat and its 14C tracer cannot be used for ECW determination in this species. The kinetics of Br- distribution were estimated in rats and in 16 human subjects by measuring plasma disappearance values and specific organ uptakes. A pharmacokinetic compartmental model was derived, containing explicit parameters for blood flow, diffusion constants, and ECW spaces separately for each organ. Precise fitting of experimental bromide data was achieved for the rat; satisfactory fitting was also achieved in man from more limited plasma and biopsy data.

The quantification of IgE antibody specific for ragweed Antigen E (AgE) on the basophil surface in patients with ragweed pollenosis

IgE antibody specific for AgE (IgE—AgE) was eluted from human basophils at acid pH and quantified by its binding of ¹²⁵I AgE in antigen excess. The quantity of Ige—AgE recovered from 30 ml of blood ranged from 0.08 ng to 10.3 ng representing 500 to 56,000 molecules IgE—AgE per basophil. The number of molecules of IgE—AgE per basophil was compared to plasma IgE—AgE, total plasma IgE and leucocyte histamine release in response to AgE.

The ratio of plasma IgE—AgE to basophil bound IgE—AgE ranged from 100 to 4000, indicating that there are a limited number of IgE receptors on the basophil surface as contrasted to the concentration of IgE in the plasma. There was no correlation between IgE—AgE in plasma and the number of molecules of IgE—AgE per basophil. However there was a significant correlation between the ration of IgE—AgE to total IgE in plasma and the number of IgE—AgE molecules per basophil.

Two measures of leucocyte histamine release in response to AgE, cell reactivity (maximum per cent histamine release attainable) and sensitivity (lowest antigen dose leading to 50% release), were compared to the number of IgE—AgE molecules per basophil. Cell reactivity was dependent on the number of IgE—AgE molecules per basophil. Only 2500 molecules IgE—AgE per basophil were required to reach a cellular reactivity of 50%. Cell sensitivity to AgE was not correlated with the number of molecules IgE—AgE per basophil which indicated that other factors played a role in determining the sensitivity of a population of basophils to antigenic stimulation by AgE.