Decreased muscle strength following management of breast cancer.

PURPOSE: To assess whether muscle strength, power and endurance at the affected shoulder were reduced in women treated for breast cancer. Secondly, we assessed whether muscle performance was explained by management or other symptoms. METHODS: Participants were 40 women (mean +/- SD: 56.7 +/- 11.6 yr) who had completed all treatments for breast cancer at least 6 m previously. We measured dynamic concentric strength at one repetition maximum (1RM), endurance at 90% 1RM, and power through a range of 40-100% 1RM for shoulder protractors, extensors and retractors. Strength and endurance, but not power, were measured for shoulder flexors. Additionally, maximal grip strength, passive shoulder range of motion and arm circumference were measured. Self-reported symptoms were recorded using a questionnaire. RESULTS: Shoulder protractors (p = 0.011), retractors (p = 0.007), and extensors (p = 0.009), but not flexors, were significantly weaker on the affected side compared to the unaffected side. Muscle power and endurance at the shoulder and grip strength were not impaired. Inter-limb differences in muscle strength were not explained by the surgical and medical management of the cancer. Self-reported weakness correlated poorly with our measures of muscle strength. CONCLUSIONS: Long-term weakness occurs about the shoulder secondary to treatment for breast cancer. Strategies to prevent weakness need to be considered.

Effect of 1,25-dihydroxyvitamin D3 on osteopenia induced by prednisolone in adult rats.

Adult male rats were fed a diet containing 0.15% calcium, 0.3% phosphorus, an either 100, 50, or 20 mg of prednisolone per kg of diet. All these levels of prednisolone led to osteopenia, decreased intestinal absorption of calcium, slightly lower serum calcium and phosphorus, and a decreased level of serum 1,25-dihydroxyvitamin D3. Exogenous parenteral 1,25-dihydroxyvitamin D3 corrected steroid-induced changes in serum calcium and phosphorus, but could not completely correct the low intestinal calcium transport; nor did it prevent the development of osteopenia. The prednisolone-induced osteopenia seems at least in part to be caused by impaired intestinal calcium transport. The impaired calcium transport may be the result of low levels of 1,25-dihydroxyvitamin D3 and a direct effect of presnisolone on the intestine.

Effect of ethanol feeding on bone composition in the rat.

The effect of ethanol feeding for a period of 3 months on the mineral and collagen content of bone was determined in the rat. Ethanol feeding resulted in no changes in the density or in the concentrations of calcium, phosphorus, hydroxyproline, or nitrogen in the tibiae. Also, the serum concentrations of calcium, phosphorus, and 25-hydroxyvitamin D were unaffected by ethanol feeding. The development of a mild degree of osteomolacia was suggested, however, by decreases in EDTA-extractable mineral content and in the calcium/hydroxyproline ratio in the tibiae of the ethanol-fed as compared with the control animals. The urinary excretion of glycosaminoglycans was not changed by ethanol-feeding while the urinary excretion of peptide-bound hydroxyproline was increased. The minimal bone changes found after ethanol feeding in this study are an unlikely cause for the observed increases in the urinary excretion of hydroxyproline.