Effect of high vegetable protein diets on urinary calcium loss in middle-aged men and women.

OBJECTIVE: To determine the effect of high-protein diets, which have recently been promoted for their health benefits, on urinary calcium losses and bone turnover in older subjects. DESIGN: Randomized controlled cross-over study. SETTING: Teaching hospital and university. SUBJECTS: Twenty hyperlipidemic men and postmenopausal women (age 56+/-2 y) completed the study. INTERVENTION: One-month test and control phases during which subjects consumed equi-energy metabolic diets high in calcium (1578 and 1593 mg/day, respectively). On the test diet 11% of total dietary energy from starch in the control bread was replaced by protein (wheat gluten), resulting in 27% of energy from protein on the test diet vs 16% on the control diet. MAIN OUTCOME MEASURE: Urinary calcium excretion. RESULTS: Compared with the control diet, at week 4, the test diet increased mean (+/-s.e.m.) 24 h urinary output of calcium (139+/-15 vs 227+/-21 mg, P=0.004). The treatment difference in urinary calcium loss correlated with the serum anion gap as a marker of metabolic acid production (r=0.57, P=0.011). Serum calcium levels were marginally lower 2.41+/-0.02 vs 2.38+/-0.02 mmol/l (P=0.075), but there was no significant treatment difference in calcium balance, possibly related to the high background calcium intake on both diets. CONCLUSION: In the presence of high dietary calcium intakes the vegetable protein gluten does not appear to have a negative effect on calcium balance despite increased urinary calcium loss.

Evaluation of the TDx method for cyclosporine and a comparison to CYCLO-Trac RIA in renal transplant patients.

The recent introduction of a fluorescence polarization immunoassay (FPIA) for cyclosporine by Abbott for their TDx analyzer provides an alternative to radioimmunoassay (RIA) and high performance liquid chromatography procedures. This new method is easier and faster than the Incstar CYCLO-Trac RIA assay. The TDx method has good precision except at low levels of cyclosporine. RIA gives consistently higher values than FPIA for samples containing only cyclosporine and in those from renal transplant patients. The FPIA procedure may be modified to allow up to a 50-min pause during the protein precipitation step, allowing more efficient use of technologists' time.

Bone penetration of enoxacin in patients with and without osteomyelitis.

Enoxacin concentrations in bone were measured in 24 patients without infection and in 7 with osteomyelitis after one or two doses of 400 mg of enoxacin administered orally or intravenously. Enoxacin concentrations were measured in serum and bone (cortical and cancellous) by high-pressure liquid chromatography. The mean concentration in serum was 2.4 +/- 1.0 micrograms/ml (range, 1.3 to 5.2 micrograms/ml) and was highest after two intravenous doses (3.1 +/- 0.9 micrograms/ml). The mean concentration in cortical bone was 1.0 +/- 0.9 micrograms/g (range, 0.4 to 4.8 micrograms/g) and was highest in patients with osteomyelitis (1.3 +/- 1.6 micrograms/g), but this was not statistically significant. The concentration of enoxacin in cancellous bone was significantly higher than that in cortical bone, with a penetration of 82 versus 40%. Oral enoxacin in practical doses can provide significant levels in bone, and further studies are warranted to determine its therapeutic efficacy in osteomyelitis.

Ciprofloxacin concentrations in bone and muscle after oral dosing.

Ciprofloxacin, a quinoline derivative with marked gram-negative and staphylococcal activity, may be a valuable orally administered agent for use against soft-tissue and bone infections. The concentrations of this antibiotic in serum, bone, and muscle samples were determined in patients undergoing orthopedic surgery. A total of 18 patients undergoing hip or knee replacement surgery or osteotomy were randomized to receive single oral doses of ciprofloxacin (500 mg, 750 mg, or 1 g); 10 patients with osteomyelitis were given single doses of 500 or 750 mg. Mean levels in bone of more than 1 microgram/g were achieved with the 750-mg ciprofloxacin doses in patients with osteomyelitis (1.4 +/- 1 microgram/g) or with the 1-g doses in patients without infections (1.6 +/- 0.6 microgram/g). The levels in muscle were significantly higher with each increasing dose level. Orally administered ciprofloxacin (750 mg given every 12 h) should provide adequate concentrations in bones and soft tissues to treat most osteomyelitis and soft-tissue infections.

The urine anion gap: the critical clue to resolve a diagnostic dilemma in a patient with ketoacidosis.

Usually, ketoacidosis presents few if any diagnostic or therapeutic problems; in this article, we report a case where ketoacidosis was clinically occult and biochemically obscure. The patient presented with acute pancreatitis associated with a modest antecedent alcohol intake. Metabolic acidosis with a normal anion gap (10 meq/L) was observed together with moderate hyperglycemia and a 2 + (but not 4 +) test for serum ketones. None of the usual causes of metabolic acidosis with a normal anion gap was identified nor was there an obvious explanation for a reduction in unmeasured anion gap (e.g., hypoalbuminemia, dysproteinemia, or the presence of abnormal halides). Despite the initial normal anion gap, ketoacidosis was suspected clinically and this was confirmed by the elevated serum B-hydroxybutyrate of 8 mmol/L. We deduced that the serum unmeasured anions, which should have been increased by at least 8 meq/L, were being underestimated because of the effect of hypertriglyceridemia on the serum chloride determination. When the serum chloride was reestimated by a method not influenced by hyperlipidemia, the value was 102 mmol/L not 112 mmol/L and, when reevaluated, the anion gap was indeed appropriately elevated. In addition, the urine anion gap (Na + K - Cl) was 103 meq/L in the absence of renal disease. This indicated that the expected large quantity of urinary ammonium must have been masked by an even greater quantity of unmeasured anion; in this case proven by direct measurement to be B-hydroxybutyrate. Finally, metabolism of the alcohol ingested, which yields hepatic NADH, could explain, in part, the modest hyperglycemia and the absence of a 4 + test for serum ketones.(ABSTRACT TRUNCATED AT 250 WORDS)