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K J Ellis

Publications and source records attributed to K J Ellis.

At least 19 recordsLinked to original sources
PubMed1996

Total body calcium and bone mineral content: comparison of dual-energy X-ray absorptiometry with neutron activation analysis.

The aim of this study was to compare the dual-energy X-ray absorptiometry (DXA) measurement of bone mass with an independent measure of body calcium obtained by neutron activation analysis (NAA). Total body bone mineral content (BMC) was measured using DXA in 46 subjects in the age range 5-47 years (17 children, 28 young women, and 1 adult male). Total body calcium (TBCa) was measured in the same subjects by in vivo NAA. The correlation between the two measures of bone mass was highly significant (BMC[g] = 3.22 x TBCa[g] - 51.4, r > 0.98, p < 0.0001, SEEBMC = 122.7 g). When BMC was the independent parameter, the SEETBCa was 37.5 g. Bland-Altman analysis indicated a mean difference of 2.8 g with a standard error +/- 4.7 g for TBCaNAA versus TBCaDXA when the BMC values were converted to TBCa. The relative change in bone mass (delta TBCa/delta BMC) for DXA was higher than that reported for dual-photon absorptiometry versus NAA. The findings presented in this study provide translational equations among the DXA and NAA measurements and for the conversion of total body BMC to TBCa in children and young adults.

Absorptiometry, Photon↗
PubMed1996

Increased efficiency of calcium absorption during short periods of inadequate calcium intake in girls.

Adequate calcium intake is essential for skeletal integrity, particularly during the period of peak bone mass acquisition from 9 to 17 y of age. Currently, the calcium intake of many adolescent girls is below the recommended dietary allowance. The purpose of this study was to evaluate the ability of girls to respond to acute periods of inadequate dietary calcium intake. Calcium absorption was evaluated in 11 girls aged 11.6 +/- 2.4 y after 10 d on both a low-calcium (7.05 +/- 2.03 mmol/d) and a high-calcium (35.30 +/- 2.28 mmol/d) diet. Fractional calcium absorption was determined by using oral (46Ca) and intravenous (42Ca) stable isotopes of calcium. During a low calcium intake, fractional calcium absorption was significantly greater (0.582 +/- 0.087 compared with 0.260 +/- 0.068, P < 0.0001) and urinary calcium excretion was significantly lower (1.30 +/- 0.83 compared with 3.08 +/- 1.98 mmol/d, P < 0.004) than values obtained during a high calcium intake. Concentrations of 1,25-dihydroxyvitamin D (combination of cholecalciferol and ergocalciferol) were greater during the low calcium intake, although the difference was not significant (108.7 +/- 30.6 compared with 90.0 +/- 25.1 pmol/L, P < 0.1; n = 9). Excretion of N-telopeptide was significantly greater during the low calcium intake (761 +/- 508 compared with 413 +/- 341 nmol bone collagen equivalent (BCM)/mmol creatinine, P < 0.02; n = 9), indicating that bone resorption was increased. These results suggest that during short periods of inadequate calcium intake, girls are able to significantly increase the efficiency of calcium absorption and decrease urinary calcium losses to conserve calcium required for bone mineral acquisition.

Absorption↗
PubMed1996

Severe protein deficiency and repletion alter body and brain composition and organ weights in infant pigs.

Three-wk-old genetically lean or obese pigs were used in two experiments to determine the changes in body composition, visceral organs and brain in response to severe protein deficiency. In Experiment 1, 16 obese pigs were fed an adequate (A, 21% protein, 3% fat) or a protein-deficient (D, 5% protein, 23% fat) diet for 7 wk. One-half of each group was killed at 7 wk, and the remainder of each group was fed the A diet for an additional 8 wk. At 7 wk, pigs fed D contained a higher percentage of fat than those fed A (P < 0.01); after 8-wk of repletion, body composition of the two groups was similar. Duodenum, jejunum, and ileum of the protein-deficient pigs had severely atrophic villi, submucosal edema, and atrophic muscle layers; after 8 wk of repletion, however, microscopic architecture of the gastrointestinal tract was restored to normal. Absolute cerebrum weight at 7 wk, but not after 8 wk repletion, in the pigs fed D were significantly less than in pigs fed A, indicating reduced brain cellularity after 7 wk of protein restriction, but not after 8 wk repletion. In Experiment 2, genetically obese (O, n = 8) and lean (L, n = 8) pigs consumed the A or D diet ad libitum for 10 wk. L and O pigs responded similarly to protein deficiency; D pigs were fatter than A pigs and plasma constituents, bone mineral content, bone mineral density and most organ weights revealed no interactions between diet and genotype. The pig model system used in these experiments enabled the isolation of protein deficiency from infectious disease, parasites and social environmental stimulation that may confound interpretation of human infant malnutrition experiments. The data suggest that genetically controlled body fatness is not a major determinant in the response of the infant pig to severe protein deficiency.

Animals↗
PubMed1996

A randomized, placebo-controlled trial of combined insulin-like growth factor I and low dose growth hormone therapy for wasting associated with human immunodeficiency virus infection.

Loss of body mass, or wasting, is a major cause of morbidity and a contributor to mortality in human immunodeficiency virus-1 (HIV-1) infection. Dietary supplements and appetite adjuvants have had limited effectiveness in treating this condition. GH and insulin-like growth factor I (IGF-I) have been shown to be anabolic in many catabolic conditions, and limited data suggest similar efficacy in HIV wasting. In addition, it appears that GH and IGF-I may have complementary anabolic effects with opposing glucoregulatory effects. We report results from a 12-week randomized, placebo-controlled trial of combination recombinant human GH (rhGH; Nutropin; 0.34 mg, sc, twice daily) and rhIGF-I (5.0 mg, sc, twice daily) in individuals with HIV wasting and without active opportunistic infection, cancer, or gastrointestinal disease. A total of 142 subjects (140 males and 2 females) were randomized using a 2:1, double blind treatment scheme and assigned to receive either active treatment or placebo injections. Eighty subjects completed the 12-week protocol. Nutritional intake and demographic and clinical characteristics did not differ between the groups at any study time point. At 3 weeks, the treatment group had a significantly larger weight increase (P = 0.0003), but this difference was not observed at any later time point. Similarly, fat-free mass, calculated from skinfold measurements, increased transiently in the treatment group at 6 weeks (P = 0.002). No significant differences in isokinetic muscle strength or endurance testing or in quality of life were observed between the groups. Resting heart rate was significantly higher in the treatment group at each time point post-baseline. GH and IGF-binding protein-3 levels did not change; however, IGF-I levels were higher in the treatment group at 6 and 12 weeks. There were no significant between-group differences in any of the measured biochemical or immunological parameters. rhGH plus rhIGF-I treatment was associated with an increased incidence of peripheral edema and other side-effects, possibly related to fluid retention. We conclude that the combination of rhIGF-I and low dose rhGH used in this study had no significant anabolic effect in HIV wasting.

Acquired Immunodeficiency Syndrome↗
PubMed1996

Changes in body composition of human immunodeficiency virus-infected males receiving insulin-like growth factor I and growth hormone.

Weight loss is a common, persistent characteristic of long term human immunodeficiency virus (HIV-1) infection; its full etiology remains unknown. Because treatment with GH has induced nitrogen retention in various catabolic conditions, we designed this study to determine whether a moderate dose of insulin-like growth factor I (IGF-I) combined with a low GH dose could impede the catabolic response seen in HIV-1 infection. A double blind, placebo-controlled study design was used. Subjects in the GH/IGF-I treatment group (n = 44) and control group (n = 22) continued to receive their routine stable antiretroviral therapy. No patient had a recent history of opportunistic infection, malignancy, or Kaposi's sarcoma and had dietary intakes of at least 25 Cal/kg weight.day at study entry. During the 12-week study period, dietary instruction was given, and subjects were encouraged to maintain an intake of 35 Cal/kg and 1 g protein/kg. All subjects had a body mass index of 19.8 kg/m2 or less at the time of study entry or a weight loss of 10% or more of their premorbid weight and a body mass index below 26.1 kg/m2. The treatment group received 0.34 mg (0.68 mg/day) GH, twice daily, and 5.0 mg (10 mg/day) IGF-I, twice daily. Changes in body composition of total body potassium (TBK), total body nitrogen (TBN), fat-free mass (FFM), and body fat (Fat) were examined at 6 and 12 weeks during the treatment period. TBK, TBN, FFM, and Fat for the treatment and placebo groups were, on the average, below normal at study entry. At 6 weeks, the GH/IGF-I group showed a significant increase in FFM (P < 0.0001), a minimal increase in TBK (P < 0.05), and a substantial decrease in Fat (P < 0.01) compared with baseline values. The loss of body fat continued to be significant (P < 0.01) in the GH/IGF-I group treatment at 12 weeks, whereas the increase in FFM was minimal (P < 0.05). No significant changes in the mean body composition occurred at 6 or 12 weeks in the placebo group. By 12 weeks, neither TBK (body cell mass) nor TBN (total protein mass) had significantly increased relative to the values at baseline, although the FFM remained elevated. Thus, the combined GH and IGF-I doses used in this study in adult males with HIV-associated weight loss were ineffective in producing a sustained anabolic response and, in fact, resulted primarily in a significant loss of body fat.

Absorptiometry, Photon↗
PubMed1995

Acute decreases in serum potassium augment blood pressure.

Potassium depletion is a risk factor for cardiovascular diseases, including hypertension, and frequently is encountered in patients with end-stage renal disease. Since the treatment of end-stage renal disease might result in K+ depletion and postdialysis hypokalemia, we investigated the relationship between acute K+ removal by hemodialysis and changes in blood pressure at the completion of treatment compared with predialysis and 1-hour postdialysis blood pressure. The effects of three different dialysate potassium concentrations ([K+]d; 1.0, 2.0, and 3.0 mmol/L) were investigated in 11 patients. Hemodialysis-induced K+ removal, serum [K+], total body K+, and blood pressure were measured. The use of 1.0, 2.0, or 3.0 mmol/L [K+]d resulted in the removal of 77.0 +/- 6.5, 54.5 +/- 7.9, and 42.5 +/- 9.9 mmol of K+ per treatment, respectively (P < 0.05, [K+]d 1.0 v [K+]d 3.0). Predialysis and postdialysis serum [K+] were 4.9 +/- 0.2 and 3.6 +/- 0.1 mEq/L for 1.0 mmol/L [K+]d, 5.1 +/- 0.3 and 3.9 +/- 0.1 mEq/L for 2.0 mmol/L [K+]d, and 5.3 +/- 0.3 and 4.2 +/- 0.2 mEq/L for 3.0 mmol/L [K+]d, respectively (P < 0.001 for each [K+]d). The baseline total body K+ corrected for gender, age, and race was 92% of predicted normal level and did not change significantly with the use of different [K+]d. Blood pressure decreased during hemodialysis as excess fluid was removed, regardless of [K+]d. Significant increases in blood pressure did occur 1 hour postdialysis compared with levels measured at the completion of treatment ("rebound hypertension") when hemodialysis was performed with 1.0 and 2.0 mmol/L, but not with 3.0 mmol/L [K+]d.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Pressure↗
PubMed1994

Accuracy of dual-energy x-ray absorptiometry for body-composition measurements in children.

The accuracy of body-composition measurements by dual-energy x-ray absorptiometry (DXA) was assessed by comparison with total carcass chemical analysis in 16 pigs with a weight range of 5-35 kg. Two software versions for body-composition analyses with the DXA instrument were evaluated. Although both software versions accurately predicted body weight, there were significant differences in the partitioning between bone mineral content (BMC), nonbone lean tissue, and body-fat compartments. All estimates of body composition were highly correlated (r2 > or = 0.98) with the results of the direct chemical reference method. SEEs were 226-271 g for body weight, 387-429 g for fat, 3.5-4.3 kg for fat-free mass, and 35.4-36.5 g for BMC. For bone, both software versions produced BMC values that were approximately 25% below the total carcass ash content. For the absolute mass of body fat, one DXA analysis provided underestimates that averaged 19.5% below the reference chemical method, whereas the alternate software version resulted in over-estimates, averaging 15.5%. Conversely, the average fat-free compartment was initially overestimated by 968 g, then underestimated by 892 g. The impact of these differences in the body-composition analyses by DXA were examined in a group of 18 young boys 4-12 y of age.

Absorptiometry, Photon↗
PubMed1994

Mineral metabolism in children with dermatomyositis.

OBJECTIVE: To measure calcium metabolism in 12 children with juvenile dermatomyositis (JDM). METHODS: We used dual-tracer stable isotope studies to measure calcium metabolism in 12 children with JDM and a group of 43 healthy children (Group HC) of similar ages. Five of the JDM subjects were receiving steroids (Group JDM-ST) and 7 were not (Group JDM-NS). RESULTS: The rate of calcium absorption in Group JDM-ST was lower than that in Group HC (19 +/- 10% vs 30 +/- 11%, p < 0.05). The lower rate of absorption was associated with a net loss of calcium each day (calculated calcium retention, Vbal, of -35 +/- 14 mg/day compared to +140 +/- 97 mg/day in Group HC, p < 0.01). Group JDM-NS showed slightly lower calcium absorption than Group HC and significantly lower Vbal (+33 +/- 70 mg/day, p < 0.01 vs Group HC) than Group HC. Group JDM-ST subjects also had decreased bone calcium deposition rates. CONCLUSION: Patients with JDM may be at risk for significant loss of bone mineral associated with decreased calcium absorption, especially in the acute phase of their disease when they are receiving steroid therapy.

Absorption↗
PubMed1993

Body composition.

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Adolescent↗
PubMed1992

Further scientific issues in determining an occupational standard for cadmium.

This contribution responds to the recent paper of Thun et al. (American Journal of Industrial Medicine 20:629-642, 1991) on an occupational standard for cadmium. The contribution of non-invasive in situ measurements of cadmium in liver and in kidney to the study of cadmium industrial toxicology is particularly reviewed. It is contended that clear scientific grounds do not exist for recommending cadmium in air occupational standard below 10 micrograms m-3, and that other arguments would need to be adduced to support a recommendation for a lower level. Last, a number of unanswered questions are identified and the need for further work is highlighted.

Air Pollutants, Occupational↗
PubMed1992

Response of blood serum constituents to production of and recovery from a kwashiorkor-like syndrome in the young pig.

Twenty-six 3-week-old genetically obese pigs were fed in two experiments to determine the serum chemistry profile during severe protein malnutrition and repletion. Severe protein deficiency was produced in pigs fed the high-fat, low-protein diet (growth failure, rough hair, low serum total protein and albumin). In Experiment 1, blood was sampled from the anterior vena cava of each pig five times during depletion and three times during repletion to determine serum total cholesterol, high density lipoprotein (HDL)-cholesterol, triglycerides, total protein, albumin, glucose, Ca, inorganic P, Mg, Na, K, Cl, total bilirubin, urea N, creatinine, alkaline phosphatase, alanine aminotransferase, aspartate aminotransferase, and gamma-glutamyltransferase. In Experiment 2, blood was sampled weekly for 8 weeks for serum total cholesterol, HDL-cholesterol, triglycerides, albumin, glucose, Ca, P, Mg and alkaline phosphatase. HDL-cholesterol was increased (P less than 0.01) and albumin was decreased (P less than 0.01) in protein-deficient pigs in both experiments. Creatinine, total bilirubin, gamma-glutamyltransferase, alanine aminotransferase, and aspartate aminotransferase were elevated in protein-deficient pigs compared with controls after 7 weeks of depletion. Inorganic P (P less than 0.01), Ca (P less than 0.01), and Mg (P less than 0.05) concentrations were depressed in protein-depleted pigs compared with controls in both experiments. After 8 weeks of repletion in Experiment 1, all elements except inorganic P were similar in the two groups. Short-term, severe, protein malnutrition affected lipid, electrolyte, and structural mineral metabolism and indices of liver function in the absence of parasites, diarrhea, and infection. The effects were reversed after 8 weeks of repletion. We conclude that the elevated serum cholesterol in protein deficiency is related primarily to an increase in the HDL fraction.

Alanine Transaminase↗