不同钙离子浓度透析液对单次血液透析钙平衡的影响

目的观察三种不同钙离子浓度透析液对维持性血液透析患者单次透析过程中血钙的影响,为透析液钙离子浓度的个体化选择提供理论参考。方法选择2014年1月在哈尔滨医科大学附属第一医院血液净化中心接受维持性血液透析治疗的患者80例为研究对象,随机分为3组,根据使用不同钙离子浓度分别为1.25 mmol/L(DCa 1.25组)、1.5 mmol/L(DCa 1.50组)和1.75 mmol/L(DCa 1.75组)的透析液进行单次血液透析治疗,每次透析4 h,3组所用透析液除钙离子浓度不同外,其他透析液主要成分组间无差别。分别检测每组透析前、后及下一次透析前的血肌酐(SCr)、尿素氮(BUN)、血白蛋白(albumin,Alb)、血钙、血磷等生化指标,同时监测单次透析前后患者的血压变化。结果对患者透析前基线数据初步分析结果表明,透析前iPTH水平为(458.7±408.2)ng/L、血钙(2.2±0.2)mmol/L、血磷(2.1±0.6)mmol/L、钙磷乘积(57.4±18.9)。iPTH、血钙、血磷达标率分别为53.8%、46.3%,25.0%;透析患者普遍伴有低钙血症(占48.8%)、高磷血症(占71.3%)和高甲状旁腺素血症(占23.8%)。单次透析治疗结束后的血钙水平分别为DCa 1.25组(2.27±0.20)mmol/L、DCa 1.50组(2.53±0.21)mmol/L、DCa 1.75组(2.51±0.20)mmol/L,组间比较差异有统计学意义(F=12.52,P0.01)。与透析前相比较,3组透析后血钙浓度较透析前均有所增加;协方差分析结果表明,在扣除透析前血钙浓度的影响因素后,DCa 1.25组血钙平均增加量最小。单次透析结束后血钙达标率分别为65.4%(DCa 1.25组)、48.1%(DCa 1.50组)、58.8%(DCa1.75组);透析结束后高钙血症的发生率DCa 1.75组(占41.2%)与DCa 1.50组(占51.9%)明显高于DCa 1.25组(占19.2%)。三种透析液对透析患者的血磷、血压影响差异均无统计学意义(P0.05)。结论单次使用钙离子浓度为1.25 mmol/L的透析液治疗,对透析后血钙浓度的影响最小、血钙达标率最高、高钙血症的发生率最低;与钙离子浓度分别为1.50 mmol/L和1.75 mmol/L透析液比较,钙离子浓度1.25 mmol/L更接近人体生理离子钙浓度。     

长期应用低钙透析对甲状旁腺激素的影响

目的：研究长期应用低钙透析液进行透析对患者甲状旁腺激素（parathyroidhormone,iPTH）的影响。方法：维持性血液透析患者16例,均使用钙浓度1.25 mmol/L的透析液透析3个月,比较血iPTH变化及透析前后的血钙磷水平的变化。结果：使用钙1.25 mmol/L的透析液3个月后,iPTH水平明显上升,透前血钙略有下降,透后血钙明显下降,血磷无明显变化。对于单次透析透后血iPTH较透前明显升高,下次透析前iPTH基本恢复,但略有上升。结论：长期应用（3个月）钙离子浓度1.25 mmol/L的透析液进行透析,会导致血iPTH的升高,但在可控制范围内。长期使用低钙透析时,应定期检查血的iPTH水平,以防发生继发性甲状旁腺机能亢进。     

低钙透析液对血液透析患者钙磷代谢及骨质重塑的影响

目的比较低钙透析液对长期血液透析患者钙磷代谢及骨重塑的影响。方法45例血清矫正钙≥9.5mgdl且iPTH≤150pgml患者随机分为透析液钙浓度1.25、1.5及1.75mmolL3组透析治疗3个月,观察3组患者血清Ca、P、Ca×P、iPTH、BGP、IGF1及IGFBP3水平差异。结果观察结束时,DCa1.5与DCa1.75组,血清Ca×P水平DCa1.5组无变化、DCa1.75组升高(P<0.05),IGF1水平2组均保持稳定;iPTH及BGP水平DCa1.5组升高(P<0.05)及DCa1.75组降低(P<0.05)。DCa1.25组血清Ca×P及IGF1水平明显降低(P<0.01),iPTH及BGP水平有显著升高(P<0.01)。透析前血清iPTH及BGP水平呈正相关(r=0.155,P<0.05)。结论低钙透析液可在有限时间内有效降低钙负荷及改善骨代谢。长期应用低钙透析液很可能通过增加iPTH、BGP水平及降低IGF1水平引发骨质疏松。     

低钙透析液对血液透析伴继发性甲状旁腺功能减退患者的临床研究

目的：探讨应用含钙1.25mmol／L浓度透析液进行血液透析对维持性血液透析（MHD）伴相继发性甲状旁腺功能减退患者的钙磷代谢和甲状旁腺功能的影响。方法：选择MHD6个月以上、病情稳定、连续2次血iPTH〈100pg／ml的患者60例,随机分为对照组（含钙1.5mmol／L透析液）和治疗组（含钙1.25mmol／L透析液）,每组各30例,观察时间6个月。观察并记录研究前、研究后l、3、6个月等不同时期患者血iPTH、血清校正钙、磷、钙磷乘积等指标的变化以及相关不良反应。另外,选择使用含钙浓度1.5mmol／L和1.25mmol／L透析液进行MHD的患者各20例,检测单次透析前、透析结束时以及下次透析前的血清校正钙、磷和iPTH浓度。结果：（1）治疗组单次透析后血清校正钙、磷和钙磷乘积均较透析前明显下降,iPTH浓度较透前明显升高,P〈0.01;而对照组上述血钙和iPTH浓度无明显变化;（2）透析后治疗组血清校正钙和钙磷乘积较对照组明显下降,血iPTH浓度较对照组明显升高,P〈0.01;两组血磷浓度差异无统计学意义。（3）治疗组1个月后血清校正钙、磷和钙磷乘积较治疗前开始下降,3个月后进一步下降,P〈0.05,6个月后各项指标趋于稳定;iPTH水平1个月后较治疗前明显升高,并随着治疗时间的延长,逐渐升高,P〈0.01。（4）对照组治疗后1、3、6个月上述指标与治疗前比较差异无统计学意义。（5）两组透析过程中出现的不良反应差异无统计学意义。结论：对于血iPTH〈100pg／ml MHD患者应用含钙1.25mmol／L透析液进行血液透析能较好地控制其血清校正钙、磷、钙磷乘积水平,有效地改善被过度抑制的甲状旁腺功能,并且安全性良好。     

观察长期使用不同钙浓度透析液对维持性血液透析患者PTH和血压的影响

目的 观察长期使用不同钙浓度透析液对维持性血液透析(HD)患者PTH和血压的影响.方法 将36例慢性肾功能衰竭维持性血透(MHD)患者随机分为两组,A组18例患者使用钙浓度为1.5 mmol/L的透析液,B组18例患者使用钙浓度为1.75mmol/L的透析液,观察透析36个月后患者血清离子钙(iCa)、磷(P)、甲状旁腺激素(PTH)及平均动脉压(MAP)的水平和临床表现.结果 B组有3例患者因高血压不能耐受试验退出.长期治疗后A组患者血清离子钙(iCa)、MAP明显降低(P＜0.05),血P无明显变化(P＞0.05),血PTH明显升高(P＜0.05);B组患者血清iCa、MAP明显升高(P分别＜0.001和＜0.01),血P无明显变化(P＞0.05)、血PTH明显降低(P＜0.05).两组患者中骨痛发生率A组为55.56％,B组为20％,部位多见于脚后跟和脚底,其次为膝关节;心律失常发生率A组为11.11％,B组为46.67％,心率失常的类型以阵发性房性期前收缩多见,其次为阵发性心房纤颤以及室性期前收缩.结论 维持性血液透析患者长期使用1.5mmol/L钙浓度的透析液后血离子钙明显下降,出现低钙血症,血PTH明显增高,肾性骨痛发病率增加,患者MAP下降;长期使用1.75 mmol/L钙浓度的透析液后血PTH明显下降,血清离子钙和MAP明显升高,骨痛发生率下降,但心律失常的发生率增加.     

不同钙浓度腹膜透析液对长期CAPD患者矿物质和骨代谢影响的分析

目的观察腹膜透析液钙离子浓度对持续性不卧床腹膜透析(CAPD)患者矿物质和骨代谢的影响。 方法回顾性分析我院腹膜透析中心行CAPD治疗2年以上的123例患者,根据腹膜透析液钙离子浓度分为低钙腹膜透析液组(LCD组,钙离子浓度为1.25 mmol/L)和标准钙腹膜透析液组(SCD组,钙离子浓度为1.75 mmol/L),观察不同钙浓度腹膜透析液对患者血清钙、磷、全段甲状旁腺激素(iPTH)、颈动脉厚度、心脏瓣膜钙化及骨痛、皮肤瘙痒等情况的影响。使用SPSS 18.0统计软件包进行数据处理。 结果2组患者治疗前人口学特征、腹膜转运特性、钙磷代谢等指标的基线水平差异无统计学意义(P>0.05)。治疗2年后,2组患者血钙浓度及达标率较治疗前均显著增高(P<0.05),SCD组血钙浓度增幅高于LCD组,但差异无统计学意义(0.26±0.31 mmol/L与0.17±0.29 mmol/L, t＝1.621,P＝0.108);2组间治疗后血清钙、磷、iPTH平均水平及其达标率、颈动脉厚度、心脏瓣膜钙化比例、骨痛及皮肤瘙痒累计发生率差异均无统计学意义(P>0.05);LCD组活性维生素D使用比例显著高于SCD组(χ² ＝6.373,P<0.05)。 结论采用低钙与标准钙腹透液治疗2年,对CAPD患者矿物质和骨代谢的影响无显著性差异。     

长期使用低钙透析液对腹膜透析患者钙磷代谢的影响

目的 观察规律性腹透患者使用低钙腹透液的有效性和安全性。方法 在规律性 随访的患者中选择高血钙和(或)高血磷,iPTH<150 pg／ml的患者25例,改用Baxter PD4透析液 (钙1．25 mmol／L,其余成分不变),同时增加碳酸钙用量。使用低钙透析液期间每1～2个月检测 血总钙、血磷、iPTH和血白蛋白,同时观察患者使用低钙透析液有何不适。结果 在使用标准钙 透析液的1年中,血钙浓度逐渐升高,血iPTH逐渐下降,并差异有统计学意义。换用低钙透析液 治疗后,第1个月的血钙值明显下降(P<0．05),且维持在正常范围。腹透治疗开始时每日碳酸 钙(2．83±0．53)g,低钙透析液治疗后每日碳酸钙为(3．57±0．74)g(P<0．05)。治疗后2个月和3 个月,血磷浓度较治疗前略有下降,差异有统计学意义。iPTH值同样在第1个月时显著升高(P <0．05),以后未观察到再进行性升高,并维持在200 pg／ml左右。血清白蛋白在治疗前后差异无 统计学意义。在整个治疗过程中,1例患者治疗2周后出现低钙,iPTH升高明显而停用低钙透析 液。其余患者能很好地耐受低钙透析,没有低血压、抽搐等情况发生。结论 在高钙、高磷、低转 运骨病的腹膜透析患者中使用钙浓度为1．25 mmol／L的透析液透析同时注意钙的补充,有助于 钙磷代谢和骨病的改善。     

透析液钙离子浓度对肾功能衰竭血液透析患者血清钙离子水平及血压的影响

目的 观察不同钙离子浓度的透析液对血液透析患者透析后血清钙离子水平及血压变化的影响，为肾功能衰竭血液透析患者的高钙血症及高血压的防治提供依据。方法 选择不同钙离子浓度的透析液，将维持性血液透析患者分为高钙组（1．75mmol／L）和低钙组（1．25mmol／L），比较患者每次透析前后脉搏、血压，同时抽查患者透析前后血钙及血肌酐浓度的变化。结果透析后两组患者血肌酐浓度均显著下降，透析前后差异均具有统计学意义（P〈0．01）；高钙组患者透析后血钙较透析前升高，差异具有统计学意义（P〈0．01），而低钙组患者血钙比透析前略降低，差异无统计学意义（P〉0．05）。高钙组患者透析后较透析前收缩压、舒张压及平均动脉压都升高，差异均具有统计学意义（P〈0．05），而低钙组患者透析后较透析前收缩压、舒张压及平均动脉压都降低，差异均具有统计学意义（P〈0．05）。透析后两组血钙比较差异具有统计学意义（P〈0．01）；透析后低钙组较高钙组患者的收缩压、舒张压及平均动脉压都降低，三者差异均具有统计学意义（P〈0．01）。结论透析液钙离子浓度与血液透析患者血清钙离子水平及血压呈正相关，低钙透析液透析有助于维持性血液透析患者高血压的控制。     

低钙透析液及盐酸米多君对血液透析患者血压的影响

目的研究低钙离子浓度1郾25mmol/L透析液(DCa1郾25),及盐酸米多君对血透患者血压的影响。方法将透前或透后高钙血症的血透患者的透析液从DCa1.5换DCa1.25,如为出现低血压则透前停服降压药;如仍低血压或原透前未服降压药者给予盐酸米多君2.5mg或5mg。观察不同钙浓度透析及加用盐酸米多君后血压和血容量变化。所有病例检测超声心动图,以及立卧位血压和持续握力试验用以反映自主神经功能。结果本组患者共21例,男9例,女12例,年龄(54.4±14.2)岁,透析龄(33.04±30.1)月。换用DCa1.25后,9(42.9%)血例压稳定,例10(47.6%)透析中出现头晕、出汗或抽搐伴随低血压;1例仅下肢抽搐;1例心前区不适。低血压组立卧位血压实验阳性者比例显著高于血压稳定组(50%比0%,P<0.05),而超滤率、白蛋白、血红蛋白、并发症、心脏收缩舒张功能及左室肥厚比例均无显著差异。低血压组的10例患者中,停服降压药仍低血压或原未服药者共例,透析前530min予盐酸米多君2.5或5mg。DCa1.25透用析时血容量较DCa1.5明显下降[(81.6±2.09)%比(86.18±2.38)%,P<0.05),盐酸米多君可提升单用DCa1.25透析时血容量[(85.96±3.10)%,P<0.05]。结论本组使用DCa1.25的患者中约50%出现低血压,与其自主神经功能低下有关。出现低血压者可停服透前降压药,无效者或     

不同钙浓度透析液治疗甲状旁腺切除术后低钙血症的探讨

目的观察血液透析患者行甲状旁腺切除术后,使用不同钙浓度透析液纠正术后低钙血症的效果。方法回顾性分析2011年10月至2014年5月我院血液透析中心行甲状旁腺切除术的13例患者,根据术后透析治疗时使用的不同钙浓度透析液,分为A组(使用钙浓度1.50 mmol/L透析液)5例,B组(使用钙浓度1.75 mmol/L透析液)8例。分别观察2组患者术后当日、术后第3、6个月透析前后的血压及透析间期的血钙、血磷、全段甲状旁腺素(intact parathyroid hormone,iPTH),比较数值之间的变化;同时统计2组患者口服钙剂的用量,并通过彩色多普勒超声心脏瓣膜评估及胸部多层螺旋电子计算机断层扫描成像(multi-slice computed tomography,MSCT)所示心脏大血管的影像学表现,比较术前及术后第6个月患者冠状动脉钙化评分分值的变化。结果比较2组单次血液透析治疗时透析前与透析结束后4 h的血钙,2组透析结束后4 h的血钙较透析前均升高,差异有统计学意义(P0.05)。同时分别比较2组透析前与术后第3、6个月时血钙变化,差异有统计学意义(P0.05)。而2组之间透析前的血磷、iPTH无统计学差异(P0.05)。通过6个月调整治疗后,血钙较术后当日明显升高(P0.05),血磷明显下降(P0.05)。术后第6个月时,B组较A组口服钙片的剂量明显减少,血压明显上升(P0.05)。同时术前及术后第6个月心脏瓣膜评估及冠状动脉钙化评分分值无明显变化(P0.05)。结论高钙透析液能更好、更快的纠正术后出现的严重低钙血症,减少维持性钙片的服用剂量,但须注意异位钙化的风险及高血压的发生。     

Conversion of calcium oxalate to calcium phosphate with recurrent stone episodes

PURPOSE: We have extended our previous observation that the percent occurrence of calcium oxalate stones decreased while that of calcium phosphate stones increased with each new stone event. MATERIALS AND METHODS: The National VA Crystal Identification Center has analyzed veteran patient urinary tract stones from VA hospitals throughout the United States since 1983. We reviewed the composition of 33,198 stones with emphasis on the changes in composition. More than 11,786 stones came from 5,088 recurrent stone formers. Stones were analyzed using high resolution x-ray powder diffraction and Fourier transform infrared spectroscopic techniques. When the stones were investigated as a function of time, it was determined that there was greater variability when samples were more than 30 days apart. RESULTS: The percent occurrence of whewellite, weddelite, apatite, brushite and uric acid in stones increased between 1.0% and 5.9% since our previous study. The percent occurrence of struvite decreased by 2.6%. The percent of calcium oxalate stones decreased while that of calcium phosphate stones increased with each new event. However, the total percent occurrence of all calcium containing stones did not significantly change with recurrent stone events. CONCLUSIONS: Our study suggests a strong trend for the conversion of stone disease from calcium oxalate to calcium phosphate containing stones, which could influence the progression and severity of disease.     

Calcium bioavailability from heated oyster shell-seaweed calcium (active absorbable algae calcium) as assessed by urinary calcium excretion

The bioavailability of heated oyster shell-seaweed calcium (active absorbable algae calcium, AAA Ca) was compared to that of calcium carbonate by measuring increases of urinary calcium excretion after oral load. Eight normal male volunteers ingested 1000 mg calcium in the form of either calcium carbonate (CaCO₃) or AAA Ca in a crossover design with a 1-week interval between the two tests. The urinary calcium/creatinine (Ca/Cr) ratio was measured from 4h before to 6h after the administration at 2-h intervals. Urinary calcium excretion 4–6 h after oral ingestion of AAA Ca was 249 ± 119% (SD) of the baseline level, which was significantly higher than that after calcium carbonate, 170 ± 103% (SD) (P = 0.039). Paired comparison of the increment of urinary Ca/Cr over the pretest level was also significantly greater 4–6h after the ingestion of AAA Ca (0.21 ± 0.14) than that after calcium carbonate (0.132 ± 0.158) (P = 0.025). AAA Ca is thus suggested to be more biologically available than calcium carbonate in human subjects.     

Calcium balance and serum ionized calcium fluctuations in on-line haemodiafiltration in relation to ultrafiltration rate and dialysate calcium concentration

The use of high ultrafiltration rates in haemodiafiltration(HDF) has been suggested for improving the clearance of smalland large molecules. This strategy has become economically applicablewith the development of safe techniques for on-line productionof sterile infusate from dialysate, which enables us to infuselarge substitution fluid volumes without further increasingthe cost of the sessions. The effect of increasing the ultrafiltrationrate in HDF on electrolyte balance has not yet been evaluated.The aim of this study was to evaluate the effects of variationsof the ultrafiltration rate on calcium kinetics in HDF usingthree different dialysate calcium concentrations. Since theincrease in ultrafiltration rate augments the convective calciumloss, variations of intrasession calcium balance could resultfrom modifications of the ultrafiltration rate. In the present study we found no significant variations in calciumbalance and serum ionized calcium (iCa) levels during on-lineHDF treatment when increasing the mean ultrafiltration ratefrom 60 to 100 ml/min in the presence of an adequate and correspondingincrease in the infusion rate (from 2.5 to 5 l/h). During thebalance studies, pretreatment serum iCa was on the average 1.32mmol/l and weight loss 3.2 kg. Mean calcium loss during treatmentwas 2.8 and 3.3 mmol at infusion rates of 2.5 and 5 l/h with1.63 mmol/l of calcium in both the dialysate and infusate; calciumloss rose to 5.9 and 11.2mmol at infusion rates of 2.5 l/h andto 5.7 and 14.2 mmol at infusion rates of 5 l/h when the dialysateand infusate calcium was reduced respectively to 1.5 and 1.25mmol/l. Serum iCa significantly increased at the end of thesession with the higher dialysate concentration, while it decreasedto 1.28 mmol/l and 1.20 mmol/l with the lower two concentrations.Linear regression ana lysis showed no variation in serum iCaduring treatment when the iCa concentration in the dialysatewas equal to pretreatment serum iCa. A neutral calcium balancewould be expected using 1.75 mmol/l of calcium in the dialysate. In conclusion, increasing the ultrafiltration rate from 60 to100 ml/min did not significantly affect calcium kinetics inon-line HDF. The main factors affecting calcium mass transferand serum iCa fluctuation during treatment were the dialysatecalcium concentration and the iCa gradient between dialysateand pretreatment serum levels.     

Calcium acetate versus calcium carbonate in chronic haemodialysis

Summary: The purpose of this study was to compare the efficacy of calcium acetate (CA) and calcium carbonate (CC) as phosphate binders in patients on maintenance haemodialysis. A randomized, blinded, crossover study was conducted for 24 weeks in 32 subjects who were stabilized on in-centre haemodialysis with low calcium (1.25 mmol/L) dialysate, were using calcium carbonate as their primary phosphate binder and had a pre-dialysis serum phosphate level of ± 1.85 mmol/L. Subjects were randomized to receive CA or CC for a period of 12 weeks, followed by the other treatment for 12 weeks; Mylanta II was added as required to achieve adequate phosphate control. There were no differences in mean serum calcium or phosphate during treatment with CA and CC, and serum parathyroid level was unchanged with both. There were four episodes of hypercalcaemia (serum Ca²⁺ > 2.70 mmol/L) while on CA compared with 11 on CC ( P = NS), and seven episodes of hyperphosphataemia (serum P₁± 2.00 mmol/L) on CA compared with 21 on CC ( P = 0.02). Signfficantly more Mylanta II was prescribed with CC than with CA after 8 or more weeks ( P <0.05). the dose of elemental Ca²⁺ ingested with CC was twice that with CA. Calcium acetate was less well tolerated than CC, and five patients withdrew from the trial because of side-effects with CA, and one with CC. In conclusion, among haemodialysis patients who can tolerate it, CA is a superior phosphate binder to CC.     

hCG/ATP-induced Leydig cell calcium channel reaction at different extracellular calcium ion concentration

Objective: To study the calcium channel reaction of human Leydig cells induced by hCG/ATP at different extracellular calcium ion concentrations. Methods: The Leydig cell calcium ion concentration was examined with laser confocal microscope, when the cells were stimulated with hCG/ATP at different extracellular calcium contrations. Results: With calcium-containing extracellular fluid, the Leydig cells were sensitive to hCG stimulation and when the extracellular fluid was calcium-free, the Leydig cells did not respond to the stimulation. However, the Leydig cells did respond to ATP stimulation no matter the extracellular fluid contained calcium or not. Conclusion: In human Leydig cells, there are calcium channels sensitive to hCG and ATP. The extracellular calcium ion concentration plays an important role in the regulation of Leydig cell metabolism by hCG/ATP.     

Tap water calcium and its relationship to renal calculi and 24h urinary calcium output in Great Britain

Summary Tap water calcium content in Great Britain has been re-determined and found to vary with geological age; the older the land mass the lower is the local tap water calcium content. No obvious correlation was observed between local tap water calcium content and the number of patients discharged from hospital with a first diagnosis of renal calculi. Variations in tap water calcium content were found to account for less than three per cent of the variation observed in 24 h urinary calcium output.     

Effect of dietary calcium on stone forming propensity

PURPOSE: Epidemiological studies have reported that high calcium diet protects against kidney stone formation in normal subjects. This metabolic study was designed to elucidate the physiological and physicochemical effects conferring this apparent protection. MATERIALS AND METHODS: A total of 21 normal volunteers underwent 2 phases of study in a crossover, randomized design, wherein they consumed constant metabolic diets that matched the estimated highest and lowest quintiles of calcium intake from published epidemiological studies. RESULTS: Urinary calcium was significantly greater on the high calcium diet (148 +/- 55 versus 118 +/- 43 mg. daily, p <0.01, p <0.01) but urinary oxalate did not differ between diets. There was no difference in relative saturation ratio of calcium oxalate between the 2 diets. The high calcium diet significantly increased saturation of brushite and decreased that of uric acid. Due to the other differences between the diets (more fluid, potassium, magnesium and phosphate in the high calcium diet), the high calcium diet also increased 24-hour urinary volume, potassium, phosphorus, pH and citrate. After adjustment of these confounding variables, the high calcium diet significantly increased relative saturation ratio of calcium oxalate by 24%. CONCLUSIONS: High calcium diet from published epidemiological studies does not alter the propensity for calcium oxalate crystallization in normal subjects despite increased urinary calcium and unaltered urinary oxalate because of the greater amounts of ingested fluid, potassium and phosphate. However, high calcium intake alone, without concomitant changes in the diet, poses a modest risk for calcium stone formation.     

Pure calcium carbonate gallstones in a two year old in association with prenatal calcium supplementation

A two-year-old female presented with cholelithiasis. Preoperative work-up revealed no etiology. Analysis of the stones revealed the content to be pure calcium carbonate. The mother had taken a calcium carbonate supplement during the last four months of the pregnancy. This represents the first report of such an occurrence.     

Effect of oral calcium loading on intact PTH and calcitriol in idiopathic renal calcium stone formers and healthy controls

The calciuric response after an oral calcium load (l000 mg elementalcalcium together with a standard breakfast) was studied in 13healthy male controls and 21 recurrent idiopathic renal calciumstone formers, 12 with hypercalciuria (U_CaxV>7.50 mmol/24h) and nine with normocalciuria. In controls, serum 1,25(OH)₂vitamin D3 (calcitriol) remained unchanged 6 h after oral calciumload (50.6±5.1 versus 50.9±5.0 pg/ml), whereasit tended to increase in hypercalciuric (from 53.6±3.2to 60.6±5.4 pg/ml, P=0.182) and fell in normocalciuricstone formers (from 45.9±2.6 to 38.1±3.3 pg/ml,P=0.011). The total amount of urinary calcium excreted afterOCL was 2.50±0.20 mmol in controls, 2.27±0.27mmol in normocalciuric and 3.62±0.32 mmol in hypercalciuricstone formers (P=0.005 versus controls and normocalciuric stoneformers respectively); it positively correlated with serum calcitriol6 h after calcium load (r=0.392, P=0.024). Maximum increasein urinary calcium excretion rate, Ca-E_max, was inversely relatedto intact PTH levels in the first 4 h after calcium load, i.e.more pronounced PTH suppression predicted a steeper increasein urinary calcium excretion rate. Twenty-four-hour urine calciumexcretion rate was inversely related to the ratio of calcitriol/PTH_maxafter calcium load (r=–0.653, P=0.0001), indicating thatan abnormally up-regulated synthesis of calcitriol and consecutiverelative PTH suppression induce hypercalciuria. Finally, lateabsorption of calcium as suggested by maximum urinary calciumexcretion beyond 4 h after oral calcium load was as rare inhypercalciuric stone formers (2 of 12) as in controls (1 of13) and did not occur in normocalciuric stone formers.