***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: BACKGROUND Intermittent oral or intravenous doses of calcitriol given two or three times per week are commonly used to treat secondary hyperparathyroidism ( secondary HPT ) . This study was undertaken to compare the biochemical and skeletal responses to thrice weekly intraperitoneal ( i.p . ) versus oral doses of calcitriol in children with secondary HPT undergoing peritoneal dialysis ( CCPD ) . METHODS Forty-six patients aged 12.5+/-4.8 years on CCPD for 22+/-25 months were r and omly assigned to treatment with oral ( p.o . ) or i.p . calcitriol for 12 months ; 17 subjects given p.o . calcitriol and 16 subjects given i.p . calcitriol completed the study . Bone biopsies were performed at the beginning and at the end of the study , while determinations of serum and total ionized calcium , phosphorus , alkaline phosphatase , parathyroid hormone ( PTH ) and calcitriol levels were done monthly . RESULTS Serum total and ionized calcium levels were higher in subjects treated with i.p . calcitriol , P < 0.0001 , whereas serum phosphorus levels were higher in those given p.o . calcitriol , P < 0.0001 . For the i.p . group , serum PTH levels decreased from pre-treatment values of 648+/-125 pg/ml to a nadir of 169+/-57 pg/ml after nine months . In contrast , serum PTH levels did not change from baseline values of 670+/-97 pg/ml in subjects given p.o . calcitriol , P < 0.0001 by multiple regression analysis . Serum alkaline phosphatase levels were also lower in patients treated with i.p . calcitriol , P < 0.0001 , but there was no difference between groups in the average dose of calcitriol given thrice weekly . The skeletal lesions of secondary HPT improved in both groups , 33 % of patients developed adynamic bone lesion . CONCLUSION Differences in the bioavailability of calcitriol and /or in phosphorus metabolism may account for the divergent biochemical response to p.o . and i.p . calcitriol Amino-terminally truncated parathyroid hormone ( PTH ) fragments are detected to differing degrees by first- and second-generation immunometric PTH assays ( PTH-IMAs ) , and acute changes in serum calcium affect the proportion of these fragments in circulation . However , the effect of chronic calcium changes and different vitamin D doses on these PTH measurements remains to be defined . In this study , 60 pediatric dialysis patients , aged 13.9 ± 0.7 years , with secondary hyperparathyroidism were r and omized to 8 months of therapy with oral vitamin D combined with either calcium carbonate ( CaCO3 ) or sevelamer  . Serum phosphorus levels did not differ between groups . Serum calcium levels rose from 9.3 ± 0.1 to 9.7 ± 0.1 mg/dl during CaCO3 therapy ( p < 0.01 from baseline ) but remained unchanged during sevelamer therapy . In the CaCO3 and sevelamer  groups , baseline serum PTH levels ( 1st PTH-IMA ; Nichols Institute Diagnostics , San Clemente , CA ) were 964 ± 75 and 932 ± 89 pg/ml , and levels declined to 491 ± 55 and 543 ± 59 pg/ml , respectively ( nonsignificant between groups ) . Patients treated with sevelamer received higher doses of vitamin D than those treated with CaCO3 . The PTH values obtained by first- and second-generation PTH-IMAs correlated closely throughout therapy and the response of PTH was similar to both PTH-IMAs , despite differences in serum calcium levels BACKGROUND Oral and intravenous calcitriol bolus therapy are both recommended for the treatment of secondary hyperparathyroidism , but it has been cl aim ed that the latter is less likely to induce absorptive hypercalcemia . The present study was undertaken to verify whether intravenous calcitriol actually stimulates intestinal calcium absorption less than oral calcitriol and whether it is superior in suppressing parathyroid hormone ( PTH ) secretion . METHODS Twenty children ( 16 males , age range of 5.1 to 16.9 years , mean creatinine clearance 21.9 + /- 11.5 mL/min/1.73 m2 , range of 7.4 to 52.7 ) with chronic renal failure ( CRF ) and secondary hyperparathyroidism [ median intact PTH ( iPTH ) , 327 pg/mL ; range 143 to 1323 ] received two single calcitriol boli ( 1.5 mg/m2 body surface area ) orally and intravenously using a r and omized crossover design .  iPTH and 1,25(OH)2D3 levels were measured over 72 hours , and intestinal calcium absorption was measured 24 hours after the calcitriol bolus using stable strontium ( Sr ) as a surrogate marker . Baseline control values for Sr absorption were obtained in a separate group of children with CRF of similar severity . RESULTS The peak serum level of 1,25(OH)2D3 and area under the curve baseline to 72 hours ( AUC0 - 72h ) were significantly higher after intravenous ( IV ) calcitriol ( AUC0 - 72h oral , 1399 + /- 979 pg/mL. hour vs. IV 2793 + /- 1102 pg/mL. hour , P < 0.01 ) , but the mean intestinal Sr absorption was not different [ SrAUC0 - 240min during the 4 hours after Sr administration 2867 + /- 1101 FAD% ( fraction of the absorbed dose ) vs. 3117 + /- 1581 FAD% with oral and IV calcitriol , respectively ] . The calcitriol-stimulated Sr absorption was more then 30 % higher compared with control values ( 2165 + /- 176 FAD% ) . A significant decrease in plasma iPTH was noted 12 hours after the administration of the calcitriol bolus , which was maintained for up to 72 hours without any differences regarding the two routes of administration . CONCLUSIONS These results demonstrate that under acute conditions , intravenous and oral calcitriol boli equally stimulate calcium absorption and had a similar efficacy in suppressing PTH secretion Secondary hyperparathyroidism was suppressed over a period of one year in 12 children with chronic renal failure by using a regimen of mild dietary phosphate restriction and high dose phosphate binders . The patients were r and omised to receive either aluminium hydroxide or calcium carbonate by mouth for six months and then crossed over to the other medication . Vitamin D ( dihydrotachysterol ) dosage was unchanged . Serum parathyroid hormone concentrations were reduced to within the normal range , urinary cyclic adenosine monophosphate values fell , plasma phosphate concentrations decreased , and the theoretical renal phosphate threshold increased significantly . Transiliac bone biopsy findings improved in four patients with adequate suppression of parathyroid hormone concentrations , deteriorated in two patients who were not compliant , and did not change in five patients in whom initial bone disease was mild . Growth velocity improved significantly . There was no difference in the clinical response , biochemical changes , or incidence of complications during treatment with the two agents . In view of the risk of aluminium toxicity the use of high dose calcium carbonate with dietary phosphate restriction and vitamin D supplementation is recommended in the control of secondary hyperparathyroidism in children with chronic renal failure T he renal bone diseases represent a spectrum of skeletal disorders ranging from the high-turnover lesions of secondary hyperparathyroidism to the lowturnover lesions of osteomalacia and adynamic bone . Secondary hyperparathyroidism is the most common skeletal lesion in pediatric patients undergoing regular dialysis ;  in contrast , the adynamic lesion of renal osteodystrophy without aluminum has become pre dominant in adult patients treated with  continuous ambulatory peritoneal dialysis ( CAPD ) ( 1 - 3 ) . Peritoneal dialysis , on the other h and , is the most common dialytic modality for children with end-stage renal disease , and persistent bone disease remains a major challenge in the clinical management of these patients . Treatment with daily doses of calcitriol or with 1,25dihydroxyvitamin D has been recommended for pediatric patients with chronic renal failure to improve linear growth and to prevent bone deformities . However , secondary hyperparathyroidism persists in a substantial proportion of patients treated with daily calcitriol therapy and receiving peritoneal dialysis ( 1,4 ) . More recently , large intermittent doses of calcitriol given two or three times per week have been used to treat secondary hyperparathyroidism in both children and adults ( 5 - 7 ) . Most studies have employed the oral or intravenous routes of calcitriol adminis tration , but there is little available information about the effect of intraperitoneal ( IP ) doses of calcitriol on bone and mineral metabolism in patients undergoing regular peritoneal dialysis .  We have recently completed a prospect i ve r and omized clinical trial to evaluate the biochemical and his tological responses to intermittent calcitriol therapy using thrice weekly IP or oral ( PO ) doses in Background There are no robust guidelines on strategies to prevent the adverse skeletal effects of glucocorticoids in children . Objectives To evaluate the role of prophylactic calcium and vitamin D on bone health in children with new-onset nephrotic syndrome ( NS ) treated with short-term ( 12 weeks ) , high-dose glucocorticoids . Methods Prospect i ve , r and omized , controlled , single blind , interventional study conducted on 41 steroid-naïve pre-pubertal children ( 29 boys , 12 girls ) . All children received prednisolone for 12 weeks ( 60 mg/m2/day daily for 6 weeks , followed by 40 mg/m2/day alternate days for 6 weeks ) . Recruited children were r and omized into the intervention group ( IG ; vitamin D 1,000 IU/day and elemental calcium 500 mg/day ) and the control group ( CG ) . Bone mineral content ( BMC ) and bone mineral density ( BMD ) at the lumbar spine ( L1–L4 ) were estimated at baseline and at 12 weeks . Mean percentage changes in BMC and BMD in IG and CG were compared . Results Children in the IG showed an increase of 11.2 % in BMC versus the CG , who showed an 8.9 % fall ( p < 0.0001 ) . Net intervention-attributable difference in BMC was 20.1 % . BMD increased in both groups ( IG 2.8 % vs CG 0.74 % ) , but the difference was not statistically significant ( p = 0.27 ) . Conclusions Short-term , high-dose glucocorticoid therapy decreases the BMC of the lumbar spine in steroid-naïve children with NS .  Vitamin D and calcium co-administration not only prevents this decline , but also enhances BMC of the lumbar spine Background The relative effectiveness and safety of sevelamer , a mineral-free phosphate binder , for treatment of hyperphosphatemia in children with chronic kidney disease is uncertain . Aim This study was design ed to compare the efficacy and acceptability of sevelamer hydrochloride to calcium acetate as a phosphate binder in pediatric patients with chronic kidney disease . Methods A 12-week open-label trial of sevelamer hydrochloride vs calcium acetate was initiated in 22 patients , aged 2–18 , with CKD stages 3 and 4 . After a 2-week washout of phosphate binders and vitamin D , patients were r and omized to receive sevelamer hydrochloride or calcium acetate . The effect of therapy was adjusted for baseline blood levels of calcium , phosphorus , calcium-phosphate product , alkaline phosphatase , PTH and GFR using ANOVA . The primary end point was the decrease in serum phosphorus levels after 12 weeks of treatment . Results Of the 22 patients enrolled , data of 19 patients were used for analysis . The adjusted mean serum phosphate levels at 12 weeks did not differ significantly between calcium acetate- ( 5.3 mg/dl ) and sevelamer-treated subjects ( 6.1 mg/dl ) ( P adjusted means = 0.6 ) . The adjusted blood level of calcium at 12 weeks was significantly lower in the sevelamer-treated patients ( 8.2 mg/dl ) compared to those treated with calcium acetate ( 9.1 mg/dl ) ( P adjusted means = 0.01 ) . In the sevelamer group , there was a non-significant decrease in serum bicarbonate , whereas the total and LDL cholesterol significantly decreased at 12 weeks ( P = 0.04 ) . Sevelamer hydrochloride was well tolerated and without adverse effects related to the drug . Conclusions Compared to calcium acetate , use of sevelamer in children with chronic kidney disease is associated with similar reduction in serum phosphate levels , lower risk of hypercalcemia , 
    Output:
    
Bone disease , assessed by changes in PTH levels , is improved by all vitamin D preparations .
However , no consistent differences between routes of administration , frequencies of dosing or vitamin D preparations were demonstrated .
Although fewer episodes of high calcium levels occurred with the non-calcium-containing phosphate binder , sevelamer , compared with calcium-containing binders , there were no differences in serum phosphorus and calcium overall and phosphorus values were reduced to similar extents .
All studies were small with few data available on patient-centred outcomes ( growth , bone deformities ) and limited data on biochemical parameters or bone histology result ing in considerable imprecision of results thus limiting the applicability to the care of children with CKD