PubMed Health⌕ Search

Biomedical subjects

C H Chesnut

Publications and source records attributed to C H Chesnut.

At least 73 records · Page 4Linked to original sources
PubMed1986

Bone mineral density after resumption of menses in amenorrheic athletes.

Amenorrheic athletes have been found to have a lower vertebral bone mineral density (BMD) than matched groups of eumenorrheic athletes. This study reports changes in BMD over a 15.5 month period in athletes who regained menses, athletes who remained amenorrheic, and athletes with regular cycles. The BMD was measured at two sites on the radius and at the lumbar vertebrae (L-1 through L-4), using single- and dual-photon densitometry, respectively. Changes in vertebral BMD were significant for the amenorrheic group (+6.3%), but not for cyclic women (-0.3%). A slight increase in radial density at S-1 and S-2 was not significant for either group. Two athletes who remained amenorrheic during this period continued to lose bone (-3.4%). We conclude that resumption of menses was the primary factor for the significant increase in the vertebral BMD of the formerly amenorrheic athletes.

Adult↗
PubMed1986

Longitudinal changes in bone mass after one year as measured by different techniques in patients with osteoporosis.

Bone mass was measured in 49 postmenopausal women by the following techniques: single photon absorptiometry at the radius (SPA), dual photon absorptiometry at the lumbar spine (DPA), quantitative computed tomography at the lumbar spine with an area of interest of only trabecular bone (QCT) or of an integrated cross-section of the vertebral body (QCTi), and total body calcium by neutron activation analysis (TBCa). Each women had two measurements with a one-year interval. Half of them were treated with calcium supplementation only; the other half also received calcitriol (1,25 dihydroxycholecalciferol). The aim of this report was to compare the changes of bone mass as measured by the different techniques. The DPA and QCTi values were significantly lower at one year than at baseline (by paired t-tests). The mean percent changes (+/- SD) for the measurements were: TBC, -0.4 +/- 4.6%; SPA-1, 1.2 +/- 7.1%; SPA-2, 0.7 +/- 6.0%; DPA, -2.5 +/- 11%; QCT, 6.5 +/- 23%; and QCTi, -6.0 +/- 9%. The percent changes by one technique did not show significant correlation to the percent changes by the other methods. We conclude that the precision of the methods in this clinical setting is not sufficient to show correlations after only one year; in addition, there may have been different rates of changes at different sites of the skeleton.

Calcitriol↗
PubMed1986

The role of skeletal calcium deficiency in postmenopausal osteoporosis.

A previous study of iliac crest composition identified skeletal calcium deficiency in 25% of 56 postmenopausal osteoporotic patients evaluated prior to the use of stanozolol or calcitonin. This report is a follow-up of biopsy data after 2 years of treatment with drug or placebo in 31 patients, 11 of whom had skeletal calcium deficiency. The study diet, consisting of 1 g elemental calcium plus 400 U Vitamin D, repaired the skeletal calcium deficiency in all patients, treated and untreated alike. Total body calcium (TBC) results were influenced by separation into calcium deficient and normal mineral groups, apparent treatment response being observed largely in patients with calcium deficiency. It is suggested that if all postmenopausal women ingested 1 g elemental calcium plus 400 U Vitamin D daily, skeletal calcium deficiency in osteoporosis would disappear as a problem. Meanwhile, it is important to recognize that repair of calcium deficiency is an important variable capable of influencing bone response to therapy and the evaluation thereof.

Bone and Bones↗
PubMed1986

Osteoblast and osteoclast cell number and cell activity in postmenopausal osteoporosis.

This study evaluates osteoblast and osteoclast cell numbers and cell activities determined from quantitative histology of trabecular bone in human iliac crest bone biopsies. Subjects studied were postmenopausal osteoporotic patients (aged 53-81) for whom total body calcium and urine and serum clinical data were also available. Only 39% of the osteoclasts identified by acid phosphatase content were multinucleate; however, a significant correlation between multinucleate osteoclasts and the total number of osteoclasts was found (r = 0.87; p less than 0.001). The mean number of osteoclasts per square millimeter of total tissue area was 0.96 (+/- 0.14, SEM, n = 36); the mean number of osteoblasts was 6.8 (+/- 1.5, n = 14)/mm2 tissue area. Computed osteoclast activity (square millimeter bone resorbed per osteoclast nucleus per day) was 2.6 X 10(-4) +/- 1.0 X 10(-4) (n = 13). Computed osteoblast activity (square millimeter bone formed per osteoblast per day) was 2.9 X 10(-5) +/- 8.8 X 10(-6) (n = 13). Calculated mean rate of bone resorption was 1.6 X 10(-4) +/- 3.4 X 10(-5) mm2 bone resorbed per mm2 total tissue area per day (n = 19). These data indicate that although osteoclasts are not numerous in the iliac crest of postmenopausal osteoporotics, the individual osteoclast activity (in square millimeter bone resorbed osteoclast cell unit per day) is significantly greater (p less than 0.001) than the osteoblast activity (in square millimeter matrix deposited per cell per day). These data also point out that greater consideration should be given to the role that osteoclast cell activity may play in human postmenopausal osteoporosis.

Aged↗
PubMed1985

Calcium balance in uremia: longitudinal study of long-term survivors.

Twelve male patients surviving uremia of 9-15 years duration were studied sequentially over a mean period of 9.2 years. Radiographs, bone biopsies, bone mineral mass (BMM) measured by photon absorptiometry, and total body calcium (TBC) determined by in vivo neutron activation analysis (NAA) were used. Pathologic fractures correlated with TBC corrected for height: 4 of 5 patients without fractures had TBC above 80% predicted, whereas 5 of 7 patients with fractures fell below this value. Unlike previous studies, negative calcium balance was seen in 3 patients with prolonged hyperparathyroidism. Though soft tissue calcification occurred in 6 patients, only 1 with massive shoulder calcification had an increase in TBC; this drawback of NAA has been previously overemphasized. Moreover, radial BMM also increased in 2 patients due to soft tissue calcification. When viewed at a single point in time, nearly all patients fell within the wide normal limits of BMM vs TBC. However, 6 patients with variable bone histology studied sequentially over a mean of 8.5 years showed significant preferential loss of radial bone mass compared to TBC. Aluminium retention did not influence calcium balance in these subjects.

Adult↗
PubMed1984

Reduction of lecithin-cholesterol acyltransferase, apolipoprotein D and the Lp(a) lipoprotein with the anabolic steroid stanozolol.

The effects of the anabolic steroid stanozolol (17-methyl-2H-5 alpha-androst-2-eno-(3,2-c)pyrazol-17 beta-ol) on lecithin-cholesterol acyltransferase, apolipoproteins B and D and the Lp(a) lipoprotein were determined in a prospective study of ten normolipidemic women with postmenopausal osteoporosis. Lecithin-cholesterol acyltransferase was reduced approx. 30% by 6 weeks of treatment with stanozolol (off treatment 5.1 +/- 1.2, on treatment 3.4 +/- 0.8 muml; P less than 0.02). The Lp(a) lipoprotein was reduced 65 +/- 23% by the steroid treatment (off treatment 5.5 +/- 5.5, on treatment 1.4 +/- 0.7 mg/dl; P less than 0.02). Apolipoprotein D was reduced 23 +/- 9% by the treatment (off treatment 5.9 +/- 0.9, on treatment 4.5 +/- 0.7 mg/dl; P less than 0.02). In contrast, apolipoprotein B increased slightly but insignificantly on steroid therapy (off treatment 90 +/- 21, on treatment 112 +/- 24 mg/dl). By 5 weeks after the drug was discontinued, all four of these proteins were near pretreatment levels. These significant changes in lipoprotein metabolism, combined with our previous report of reductions of HDL and particularly HDL2, suggest the need for caution in the long-term use of anabolic steroids.

Aged↗
PubMed1984

Bone mineral content of amenorrheic and eumenorrheic athletes.

This study was designed to determine whether the hypoestrogenic status of 14 amenorrheic athletes was associated with a decrease in regional bone mass relative to that of 14 of their eumenorrheic peers. The two groups of athletes were matched for age, height, weight, sport, and training regimens. Bone mass was measured by dual-photon and single-photon absorptiometry at the lumbar vertebrae (L1 to L4) and at two sites on the radius. Vertebral mineral density was significantly lower in the amenorrheic group (mean, 1.12 g per square centimeter) than in the eumenorrheic group (mean, 1.30 g per square centimeter). There was no significant difference at either radial site. Radioimmunoassay confirmed a lower mean estradiol concentration (amenorrheic group, 38.58 pg per milliliter; eumenorrheic group, 106.99 pg per milliliter) and progesterone peak (amenorrheic group, 1.25 ng per milliliter; eumenorrheic group, 12.75 ng per milliliter) in the amenorrheic women, in four venous samples drawn at seven-day intervals. A three-day dietary history showed no significant differences in nutritional intake, including calcium with and without supplements. The two groups were similar in percentage of body fat, age at menarche, years of athletic participation, and frequency and duration of training but differed in number of miles run per week (amenorrheic group, 41.8 miles [67.3 km]; eumenorrheic group, 24.9 miles [40.1 km]). We conclude that the amenorrhea that is observed in female athletes may be accompanied by a decrease in mineral density of the lumbar vertebrae.

Adult↗
PubMed1984

Long-term calcitonin therapy in postmenopausal osteoporosis.

Results are presented from a 2-year controlled study evaluating the efficacy of 100 units synthetic salmon calcitonin/d in the treatment of postmenopausal osteoporosis. All patients received 400 units D2 po qd and 1200 mg CaCO3 po qd. The 21 control and 24 treated patients (mean age 65) were not statistically different at baseline. Although mean total body calcium (TBCa) was not significantly different between treated and control patients throughout the study, mean differences in the change in TBCa from baseline (treated minus control) were significant at 12, 18, and 26 months. The mean slope of TBCa for treated patients, but not for controls, was significantly positive through 18 months. Iliac crest bone biopsies showed (1) a significantly greater percent total bone area in treated compared to control patients at 2 years, and (2) a significantly decreased percent resorbing surface in treated patients when evaluated by paired difference from baseline. At 4 months, serum calcium values were significantly lower in treated patients than in controls (mean difference, treated minus controls), but were not statistically different from controls at study completion. Urine calcium increased significantly for the first 4 months in treated subjects and then declined to baseline levels. Since urinary calcium increased, the increase in TBCa was probably associated with an increase in net intestinal calcium absorption.

Age Factors↗
PubMed1983

Stanozolol in postmenopausal osteoporosis: therapeutic efficacy and possible mechanisms of action.

To assess the efficacy of the anabolic steroid stanozolol in the treatment of osteoporosis, a 29-month double-blind study was performed with 23 treated and 23 control postmenopausal osteoporotic women. Drug efficacy was assessed by serial determinations of total body calcium (TBC--total bone mass) by neutron activation analysis, regional bone mass (RBM) by single-photon absorptiometry, and by spinal roentgenograms. Total body calcium increased 4.4% from baseline values (P less than 0.01) in the treated group and remained unchanged in the control group; the difference in the change in TBC between the treated and control groups was significant (P less than 0.03). The effect of the drug on TBC persisted throughout the 29-month period. In contrast to TBC, measurements of RBM indicated no significant differences between the treated and placebo groups, suggesting a possible differential response to therapy at various skeletal sites. No new spinal compression fractures were noted in the treated group (compared with three new fractures in the control group). Assessment of serum and urine values indicated a decrease in the level of urinary calcium and an increase in the level of total urinary cyclic AMP in the treated group. These changes were observed even though the level of serum iPTH was significantly decreased during the study. An analysis of changes in bone biopsy specimens revealed no significant differences between the treated and control groups. Seventy-six percent of the treated subjects developed SGOT elevations or other side effects from the stanozolol therapy; at no time were these effects sufficiently severe to cause termination of medication. The data suggest that long-term use of stanozolol increases the net total bone mass above pretreatment levels.

Aged↗
PubMed1982

Deficient calcitonin response to calcium stimulation in postmenopausal osteoporosis?

To test whether mobilisation of immunoreactive calcitonin in response to calcium challenge is reduced in postmenopausal osteoporosis, seventeen postmenopausal osteoporotic women with compression fractures and ten normal age-matched women were given intravenous infusions of 3 mg/kg elemental calcium over a 10 min period. Blood samples were obtained 5 min before and at 0, 10, 20, and 60 min after start of infusion for the measurement of serum calcium and plasma immunoreactive calcitonin. Serum calcium increased significantly from baseline in both normal and osteoporotic groups; immunoreactive calcitonin increased significantly in the controls 10 min and 20 min after the start of infusion, but in the women with osteoporosis calcitonin levels did not change significantly at any time. 20 min after the start of infusion the change in immunoreactive calcitonin from baseline was significantly less in osteoporotic women than in the controls. These data are consistent with a decreased immunoreactive calcitonin response to calcium infusion in postmenopausal osteoporotic women, and suggest that calcitonin deficiency may be involved in the development of postmenopausal osteoporosis.

Aged↗