Effect of RenaGel, a non-absorbed, calcium- and aluminium-free phosphate binder, on serum phosphorus, calcium, and intact parathyroid hormone in end-stage renal disease patients

BACKGROUND: Control of dietary phosphate absorption in end-stage renal disease patients is essential to prevent the deleterious sequelae of phosphorus retention. Efficacy of currently available calcium- and aluminium-containing phosphate binders is constrained by the side-effects associated with the absorption of calcium and aluminium. The current study examined the efficacy of RenaGel, a calcium- and aluminium-free, polymeric phosphate binder, in end-stage renal disease patients. METHODS: Administration of calcium- or aluminium-containing phosphate binders ceased during a 2-week washout period. RenaGel, at starting doses of one, two, or three 500-mg capsules three times per day with meals, was administered for 8 weeks. RenaGel dose was titrated up 1 capsule per meal at the end of each 2-week period if necessary to achieve phosphorus control. A second 2-week washout period followed the end of RenaGel treatment. RESULTS: Mean serum phosphorus rose from a pre-washout level of 6.9 mg/dl (2.23 mmol/l) to 8.1 mg/dl (2.62 mmol/l) at the end of the initial 2-week washout. With RenaGel treatment, serum phosphorus declined and returned to pre-washout levels after 4 weeks. Serum phosphorus reached a nadir of 6.5 mg/dl (2.10 mmol/l) after 7 weeks of RenaGel treatment. Serum phosphorus rose to 8.2 mg/dl (2.65 mmol/l) 2 weeks after cessation of RenaGel treatment. As anticipated, calcium declined during the initial washout period when calcium-based phosphate binders were stopped for the majority of patients. The rise in serum phosphorus and decline in serum calcium during washout resulted in an increase in median intact parathyroid hormone (iPTH) levels from 292 pg/ml to 395 pg/ml. iPTH fell to 283 pg/ml after 6 weeks of RenaGel treatment despite a persistently lower serum calcium. RenaGel treatment also reduced serum total and LDL cholesterol by 25 mg/dl (0.65 mmol/l) and 23 mg/dl (0.59 mmol/l) respectively. CONCLUSIONS: RenaGel appears to be an effective phosphate binder free of calcium and aluminium. Phosphorus control with two to four RenaGel capsules per meal appears to result in comparable phosphorus lowering seen with calcium- or aluminium-based phosphate binders. RenaGel may offer an alternative for the control of phosphorus retention in end-stage renal disease patients.     

生物质木炭用于鲕状高磷铁矿除磷

针对难处理的鲕状高磷铁矿,提出了首先采用高气化性生物质木炭制备含碳球团,然后通过直接还原-高温熔分的方法,成功实现了该铁矿的除磷提铁.直接还原实验采用管式炉.考察了还原温度、生物质木炭加入比例（碳氧摩尔比）和气氛等条件对样品还原行为的影响,并确定了适宜的还原条件为温度1373 K、配碳量0.9、时间15～25 min以及气氛P_CO2/P_CO=1:1.在此条件下,样品的金属化率和残碳质量分数分别在75%～80%和0.69%～0.11%的范围内.通过对该金属化球团的X射线衍射和扫描电镜-能谱分析发现:还原后样品中的主要物相为金属铁、磷灰石和硅酸三钙;磷没有被还原而仍以磷灰石的形式存在于脉石中.高温熔分实验采用Si-Mo棒高温箱式炉.实验结果得到磷质量分数为0.4%的铁样.在熔分体系中进一步添加相对质量为2%～4%的Na₂CO₃,可以得到磷质量分数在0.3%以下的铁样.基于以上分析,证明了采用生物质木炭用于高磷铁矿的除磷提铁是可行的.      

A randomized trial of sevelamer hydrochloride (RenaGel) with and without supplemental calcium. Strategies for the control of hyperphosphatemia and hyperparathyroidism in hemodialysis patients

OBJECTIVE: We have previously shown sevelamer hydrochloride (RenaGel) to be an effective and well-tolerated treatment for hyperphosphatemia in hemodialysis patients. PATIENTS AND METHODS: We performed a randomized clinical trial to compare the efficacy of RenaGel alone and RenaGel with calcium, using the serum phosphorus concentration and intact parathyroid hormone (PTH) as the principal outcomes of interest. Calcium (900 mg elemental) was provided as a once-nightly dose on an empty stomach. 71 patients were randomized and included in the intent-to-treat population; 55 completed the 16-week study period (2 weeks washout, 12 weeks treatment, 2 weeks washout). 49% of subjects were taking vitamin D metabolites. RESULTS: Serum phosphorus and PTH rose significantly when patients stopped their phosphate binders during both washout periods. RenaGel and RenaGel with calcium were equally effective at reducing serum phosphorus (mean change -2.4 mg/dL vs. -2.3 mg/dL). RenaGel with calcium was associated with a small increase in serum calcium (mean change 0.3 mg/dL vs. 0.0 mg/dL in RenaGel group, P = 0.09) that was not statistically significant. During the treatment phase, the reduction in PTH tended to be greater in the RenaGel with calcium group (median change -67.0 vs. -22.5 pg/mL in RenaGel group, P = 0.07). Non-users of vitamin D metabolites treated with RenaGel with calcium experienced a significant decrease in PTH (median change -114.5 vs. -22 pg/mL in RenaGel group, P = 0.006). Adverse events were seen with equal frequency in both groups, being generally mild in intensity, and rarely attributable to the drugs. CONCLUSION: We conclude that RenaGel and RenaGel with calcium are similarly effective in the treatment of ESRD-related hyperphosphatemia. Provision of supplemental calcium or metabolites of vitamin D with RenaGel may enhance control of hyperparathyroidism.     

Risedronate, a highly effective oral agent in the treatment of patients with severe Paget's disease

Thirteen patients with severe Paget's disease of bone [mean serum alkaline phosphatase (SAP) level 17 times the upper limit of normal] were treated with 30 mg oral risedronate daily for 8 weeks. Patients were followed for 16 weeks without treatment. The change from baseline SAP was the primary end point. Those patients whose SAP levels did not reach the normal range were retreated with 30 mg for another 8 weeks. There was a mean percent decrease in SAP of 77% after the first course of risedronate treatment and 87% after the second course of treatment. All patients who completed the study had a decrease in SAP of at least 77% from the baseline. The urinary hydroxyproline/creatinine level was decreased by 64% and 79%, respectively, during the first and second treatment courses. There were transient asymptomatic decreases in serum calcium and phosphorus levels. The urinary calcium/creatinine ratio also decreased in these patients. Serum intact PTH and 1,25-dihydroxyvitamin D levels increased transiently during risedronate treatment. Oral risedronate was well tolerated by the patients. Only one patient discontinued treatment because of an adverse event (diarrhea) thought to be related to risedronate therapy.     

Importance of proteins in the deterioration of the remnant kidneys, independently of other nutrients

Several experiments have shown that deterioration of renal parenchyma after reduction of functional mass is affected by the protein content of the diet. The respective role of proteins and that of other nutrients particularly phosphorus which varies with proteins was never clearly separated. Three groups of 9 uremic rats U I, U II, U III, received three diets differing exclusively in their protein content, which was supplied by casein and was respectively 8%, 16% and 32%. Other nutrients were maintained identical, including energy and minerals. Food intake was similar in U I and U II rats and was lower in U III rats. Mortality rate remained closely related to protein intake. Of U III rats, 78% died within 10 weeks and 100% within 15 weeks. Of U II rats, 56% were dead at week 15, and 100% at week 30. Mortality occurred significantly later in U I rats fed the lowest protein diet. Histology of remnant kidneys showed severe glomerular and tubular damage, with no or little calcium deposits despite normal phosphorus diet and frequent hyperphosphoremia. In conclusion, protein intake influences survival by accelerating the renal damage in rats with reduced kidney mass independently of any other nutrient.     

磷钼蓝分光光度法测定工业硅中磷

采用氢氟酸-硝酸溶解样品,高氯酸冒烟驱除硅、氟,加入抗坏血酸、显色溶液后直接显色测定,建立了磷钼蓝分光光度法测定工业硅中0.001%～0.27%磷含量的分析方法。结果表明,溶液中磷质量浓度在0.05～1.40 μg/mL范围内符合比尔定律;方法中磷的检出限为0.000 46 μg/mL;表观摩尔吸光系数ε₈₂₅=2.75×10⁴ L·mol^-1·cm^-1;样品中其他共存离子不干扰测定。不同实验室应用实验方法测定3个工业硅行业标准样品中磷的结果均与认定值吻合;按照实验方法测定2个工业硅行业标准样品中磷的结果与国标方法GB/T 14819.4－2012和GB/T 14819.5－2012的测定值均基本一致。将实验方法用于工业硅行业标准样品和工业硅实际样品中0.001%～0.27%磷的测定,实验所得结果的相对标准偏差(RSD,n=22)为1.4%～4.5%。
     

污泥炭田间老化对土壤重金属及养分的影响

污泥基生物炭内源重金属和养分含量因污泥来源的不同而差异较大。为探索污泥基生物炭“还田”后，其内源重金属变化和养分的去向问题，采用干湿交替对污泥基生物炭模拟老化处理，分析老化前后污泥基生物炭的Cu、Zn金属形态及TCLP浸出毒性的变化；研究污泥基生物炭BC1和BC2（分别以磷酸二氢钾、磷酸二氢钙与污泥混合后热解制备的生物炭）以5%和10%的质量分数与鲜土混合老化后对污泥基生物炭内源重金属稳定性及土壤有机碳和有效磷含量变化的影响。结果表明：两种污泥基生物炭与土壤混合老化后会使土壤中SiO2含量增加，但不会改变土壤的吸附类型；污泥基生物炭的添加会增加土壤的比表面积，其中BC2增幅较大，为36.17 m2/g；施加两种污泥基生物炭土壤中Cu、Zn生物有效性均有不同程度的降低。TCLP浸出毒性量相比老化前降低（BC1约降低37.5%）。此外，BC1对土壤有效磷的提升效果优于BC2（BC1 70 mg/kg，BC2 30 mg/kg）；BC2对土壤有机碳的提升效果优于BC1（BC2 2.2%，BC1 1.15%）。BC2还田更有利于Cu、Zn的固定以及土壤有机碳和有效磷的提升。     

电感耦合等离子体原子发射光谱法测定偏钒酸铵中10种杂质元素

样品采用盐酸溶解后,以电感耦合等离子体原子发射光谱法(ICP-AES)同时测定了偏钒酸铵中10种微量杂质元素铝、铁、硅、磷、铅、砷、铬、钾、钠、钙的含量。由于样品溶液中含有2.18 g/L钒和0.78 g/L铵根,故实验重点考察了2.18 g/L钒标准溶液、0.78 g/L铵根标准溶液及两者的混合标准溶液,以及10 mg/L各待测元素标准溶液、水和5%(V/V)盐酸试剂空白的谱线重叠与连续背景叠加等光谱干扰以及基体效应对待测元素测定的干扰影响情况。结果表明:该质量浓度的铵根对测定无影响,部分待测元素灵敏谱线受到钒基较严重的光谱重叠或旁峰干扰;高质量浓度钒的基体效应、连续背景叠加等影响因素导致铝、铁、硅、磷、铅、砷、铬、钙的谱线强度增加,对其产生正干扰,同时高质量浓度钒的基体效应也导致钾、钠的谱线强度降低,对其产生负干扰。为此实验方法采用基体匹配和同步背景校正相结合的校正措施消除了高钒基体影响,同时试验优选了未受光谱干扰的各待测元素分析谱线及其背景校正和检测区域。结果表明,背景等效浓度为－0.000 3%(Na)～0.000 4%(Ca);铝、铁、硅、磷、铅、砷、铬、钙在0.001%～0.60%(质量分数)范围内,钾、钠在0.005%～0.60%(质量分数)范围内,其质量分数与其对应的发射强度呈线性,各元素校准曲线的相关系数均不小于0.999;方法中各元素检出限为0.000 1%～0.000 6%。按照实验方法测定两个偏钒酸铵样品中铝、铁、钾、钠、硅、磷、铅、砷、铬、钙,结果的相对标准偏差(RSD,n=8)分别为小于10%(质量分数为0.001%～0.010%),小于7%(质量分数为0.010%～0.050%),小于3%(质量分数大于0.050%);实验方法用于测定4个偏钒酸铵样品中铝、铁、硅、磷、铅、砷、铬、钾、钠、钙,结果与电感耦合等离子体质谱法(ICP-MS)测定结果相吻合。     

60t LF精炼终点GCrl5轴承钢中氧化物夹杂特性的研究

通过电弧炉出钢加铝铁、硅铁脱氧,LF精炼初渣的组分为(/%:27.39~37.34 Al₂O_3,38.42~38.68 CaO,14.20~18.38 SiO_2,8.50~10.72 MgO,0.82~0.89 FeO,0.27~0.33 MnO,0.69~0.74 S,0.66~0.75TiO₂,（CaO）/（SiO₂）=2.09~2.72,（CaO）/（Al₂O₃）=1.04~1.40),LF终点T[O]为0.0012%~0.0019%,T[N]为0.0043%~0.0050%,[Ti]0.002%和[Ca]0.006%~0.009%。GCr15轴承钢LF精炼终点氧化物夹杂分析结果表明,钢中主要氧化物夹杂为镁铝尖晶石（MgO·Al₂O₃）和钙镁铝尖晶石氧化物（CaO·MgO·Al₂O₃）。镁铝尖晶石平均尺寸低于0.5μm,当有MnS、TiN等在其上析出后平均尺寸增大。钙镁铝尖晶石平均尺寸通常在2μm以上,在精炼温度下呈液态,易在钢中聚集长大,其尺寸（1.39~2.12μm）比固态的钙镁铝尖晶石-MnS夹杂物大,且更被精炼渣吸收并上浮去除。随着精炼过程钢液中的硫含量降低,以这两类尖晶石为核心的含MnS的复合夹杂物的平均尺寸降低。适当降低精炼终点渣中MgO的含量、光学碱度和黏度可以减少钢中夹杂物的数量并降低其平均尺寸。     

Elemental distributions in predentine associated with dentine mineralization in rat incisor

Electron probe microanalysis was applied to study quantitatively and semi quantitatively the elemental concentrations and distributions that occur in predentine during the dentine mineralization of rat incisor. Apex regions of the continuously growing incisors were rapidly dissected and cryofixed in liquid nitrogen-cooled propane. Ultrathin cryosections were prepared from the dentine tissue. On the average in the extracellular predentine element concentrations of calcium and phosphorus were about 0.5% (w/w) and 0.5-1% (w/w), respectively; so the calcium content in the extracellular predentine is higher while the phosphorus content is much lower than in the odontoblast area. Due to the high content of glycosaminoglycans in the extracellular matrix the concentration of sulfur in the predentine was more than 1% (w/w); the potassium content was found in the range of 0.6-0.8% (w/w) which is quite high for an extracellular area and the concentrations of sodium and chlorine were higher than 2% (w/w). Elemental mapping analysis was carried out to demonstrate the distribution of some important elements at the predentine/dentine border during mineralization.     

Tubulointerstitial disease in aging: evidence for underlying peritubular capillary damage, a potential role for renal ischemia

A feeding trial was performed using 4 x 60 day-old chickens (Ross 208 cockerels) raised up to 42 days of age to determine whether exogenous phytase addition increases phosphorus utilisation by broiler chickens, and to assess its effects on some production traits as well as on the ash content and mechanical stability of the tibia. The chickens' feed consisted of maize, wheat, soybean meal, fish meal, yeast, and fat powder. The basic feed was supplemented with inorganic phosphorus in groups A and B. In groups C and D, the amount of the inorganic phosphorus supplement (DCP) was decreased by 50%, at the same calcium/phosphorus ratio. The 50% reduction of inorganic phosphorus supplementation represents a 20% decrease of total phosphorus. To the diets of groups B and D a phytase enzyme preparation (Phytase Novo CT) was added. The calculated exogenous phytase activity was 600 FYT/kg feed. The decrease of inorganic phosphorus did not cause significant differences in the daily weight gain but lowered the feed conversion rate by 10%. Calcium and phosphorus excretion decreased by 18% and 15%, and the breaking strength of the tibia was also lower. Phytase supplementation of the feed at a lower rate of inorganic phosphorus supplementation did not cause changes in the body weight gain but improved the feed conversion rate by 5.6%. Phosphorus and calcium output decreased by 21% and 11%, respectively, but chemical composition and mechanical stability of the tibia were unaltered.     

Selective ETA receptor blockade prevents left ventricular remodeling and deterioration of cardiac function in experimental heart failure

BACKGROUND: Left ventricular (LV) dilation, which is a predictor of survival in humans with chronic heart failure (CHF), is limited by a mixed endothelin ETA-ETB antagonist. Whether selective ETA receptor blockade influences LV dilation is unknown. We determined, in a rat model of CHF, the effects of the ETA receptor blocker LU 135,252 on LV remodeling. METHODS AND RESULTS: Rats were subjected to coronary artery ligation and treated for ten weeks with placebo or LU 135,252 (LU), at a dose of 10 or 30 mg kg-1 day-1. Systolic blood pressure and heart rate (plethysmography) were determined in conscious animals before and after four and ten weeks of treatment. At these time points, cardiac output and LV dimensions were measured in anesthetized rats by transthoracic echocardiography. LV hemodynamics were determined in anesthetized rats after ten weeks. Pressor responses to ET-1 (1 nmol/kg, i.v.) and sarafotoxin S6c (0.3 ng/kg, i.v.) were measured, to assess the efficacy of ET receptor antagonism and the lack of blockade of ETB receptor blockade, respectively. The pressor response to ET-1 was significantly reduced by LU (% change in systolic blood pressure: sham: 9 +/- 1; CHF: 5 +/- 1; CHF LU: 0 +/- 3 and -4 +/- 2% for the low and high dose, respectively). LU did not affect the response to sarafotoxin (CHF: -37 +/- 3; CHF LU: -29 +/- 3 and -28 +/- 2% for the low and high dose, respectively). Both doses of LU decreased systolic blood pressure, but only the high dose of LU reduced heart rate. Furthermore, LU restored cardiac output dose-dependently throughout the study. Both doses of LU limited LV dilatation and deterioration of LV fractional shortening to the same extent. After ten weeks, LU normalized LV end-diastolic- and central venous pressures, but did not affect LV dP/dtmax or dP/dtmin. LU did not prevent the development of cardiac hypertrophy, but reduced LV collagen density. CONCLUSIONS: In this rat model, the selective ETA receptor blocker LU, at the dose of 30 mg kg-1 day-1, reduced blood pressure and heart rate, limited progressive left ventricular remodeling and improved cardiac hemodynamics and function. These effects of LU might have important clinical relevance in the treatment of heart failure.     

Influence of aging on cortical and trabecular bone response to estradiol treatment in ovariectomized rats

Three groups (n = 15/group) of 6-, 12- and 30-month-old (mature, old and senescent animals, respectively) female Wistar rats on a diet (6 g/100 g BW/ day) containing 0.8% calcium and 0.8% inorganic phosphorus were studied. Within each group, 10 rats were ovariectomized surgically and 5 injected s.c. with 17 beta-estradiol (E rats, 10 micrograms/kg BW/48 h) and 5 with solvent alone (OVX rats) from day 2 until day 60 after ovariectomy. Five other rats were sham-operated (SH rats) and received solvent only. All rats were killed by exsanguination 60 days after ovariectomy. Neither ovariectomy nor estradiol treatment had a significant effect upon tibial mechanical properties in 6-, 12- and 30-month-old animals. Bone mineral density (BMD) and bone mineral content (BMC) of the distal femur and BMC of the whole femur were decreased by ovariectomy in 6- and 12-month-old rats, but were not different in the SH and E groups. In senescent animals, in which the lowest BMD and BMC were measured, estradiol treatment was more effective in increasing these parameters than in adult and old rats. Image analysis of the distal femoral diaphysis showed that estradiol treatment prevented trabecular bone loss induced by senescence and/or ovariectomy. In each group, urinary deoxypyridinoline excretion and plasma osteocalcin concentration were higher in the OVX animals than in the controls, consistent with increased bone turnover in the estrogen-deficient state. Both biochemical turnover markers were reduced in the estrogen-treated groups. These results indicate that 17 beta-estradiol is particularly effective at preventing high-turnover-induced osteopenia in 30-month-old animals.     

Effect of enalapril on proteinuria, phosphaturia, and calciuria in insulin-dependent diabetes

Elevated urinary calcium and phosphate excretion have been observed in children with insulin-dependent diabetes mellitus (IDDM). This may be related to a defect in tubular reabsorption. It is well known that converting enzyme inhibition decreases microalbuminuria and may prevent or retard diabetic nephropathy. We investigated whether enalapril also improves the defect in calcium and phosphate reabsorption. We studied 16 children and young adults (age 12-21 years) with IDDM and persistent microalbuminuria before and during 12 weeks of enalapril treatment. Before treatment microalbuminuria, urinary calcium excretion, and fractional tubular phosphorus reabsorption (TPR) were 153+/-53 microg/min, 5.5+/-0.9 mg/kg per day, and 71.4+/-3.6%, respectively. At the end of the 12th week, microalbuminuria had decreased to 20.3+/-7.9 microg/min and calcium excretion to 3.3+/-0.4 mg/kg per day (P<0.01), while the TPR increased to 80.1+/-3.8% (NS). The renal threshold phosphate concentration increased from 1.8+/-0.15 to 2.92+/-0.23 mg/dl (P<0.01). The fasting serum glucose and hemoglobin Alc levels did not change significantly during the study. Systolic and diastolic blood pressures were 120.4+/-2.2 / 79.3+/-1.4 mm Hg and 110.5+/-1.8 / 71.3+/-0.9 mm Hg before and after 12 weeks, respectively. We conclude that enalapril treatment improves not only microalbuminuria but also abnormal calcium and phosphate excretion in microalbuminuric children with IDDM.     

N2733, 1-[3-(3-pyridyl)-acryloyl]-2-pyrrolidinone hydrochloride inhibits LPS-induced TNF-alpha production and improves survival in endotoxemic mice

N2733, 1-[3-(3-pyridyl)-acryloyl]-2-pyrrolidinone hydrochloride, was examined for its effect on TNF-alpha production by human myeloid THP-1 cells stimulated with lipopolysaccharide (LPS). N2733 inhibited LPS-induced release of TNF-alpha from THP-1 cells with an IC50 of 11 microM. N2733 did not affect the cell viability at the concentration of 50 microM or 100 microM. This indicates that N2733 is a potent inhibitor for TNF-alpha production without severe cytotoxicity. N2733 was also studied in two murine endotoxin shock models induced with LPS. One model was DBA/2 mice injected with LPS (5.6 mg/kg, i.v.), which increased the serum level of TNF-alpha within 1 hr. Treatment of these mice with N2733 (100 mg/kg x 2, i.p.) decreased the serum level of TNF-alpha significantly. Another model was DBA/2 mice induced with LPS (30 mg/kg, i.v.), which reduced the survival rate to 30% during 7 days. Administrations of 30 mg/kg and 100 mg/kg N2733 (i.v.) restored the survival rates to 60% and 90% respectively. Our data demonstrate that N2733 inhibits LPS-induced TNF-alpha production, and this response is associated with an improvement in the survival rate of endotoxemic mice.     

Deficient muscle carnitine transport in primary carnitine deficiency

The effects of conditions that either increase or decrease heart rate on the pharmacological properties of adenosine receptors in cultured rat myocytes were examined. Levels of A1 adenosine receptors, following prolonged treatment with electrical stimulation (ES) or the antiarrhythmic drug amiodarone, were determined using radioligand binding with the specific A1 receptor antagonist [3H]1,3-dipropyl-8-cyclopentylxanthine (CPX). The effects of lowering temperature were also explored. Exposure to amiodarone for 4 days reduced the density of A1 receptors by 19% (from 24.7 +/- 0.4 to 20.09 +/- 0.3 fmol/dish) and inhibited the rate of contraction by 60% (from 188 +/- 16 to 76 +/- 30 beats/min), without changing the receptor affinity, protein content, creatine kinase (CK) activity or cell number. Electrical stimulation at 25 degrees C elevated the density of A1 adenosine receptors by 185% (from 4.1 +/- 0.4 to 11.69 +/- 2.1 fmol/dish). Four days of reduced temperature (from 37 degrees C to either 30 or 25 degrees C) lowered the density of A1 adenosine receptors by 69 or 86%, respectively (from 24.1 +/- 1.2 to 7.4 +/- 0.4 or 3.4 +/- 0.3 fmol/dish), with no significant change in the receptor affinity, activity of CK, or lactate dehydrogenase (LDH), protein content or cell number. The observed up- and down-regulation of A1 adenosine receptors in primary myocyte cultures in response to conditions that exogenously alter the rate of contraction, is indicative of the role of adenosine receptors in adaptation of heart cells to stress.     

Concentration of ionized calcium in plasma from cats with urethral obstruction

OBJECTIVE: To measure ionized calcium concentration in plasma from cats with urethral obstruction and to correlate these values with results of clinical biochemical analyses and physical examinations. DESIGN: Prospective study. ANIMALS: 24 male cats. PROCEDURE: Blood samples were obtained from each cat on admission, and PCV, pH, and concentrations of ionized calcium, total calcium, glucose, total solids, sodium, potassium, BUN, creatinine, chloride, magnesium, albumin, and phosphorus were determined. Mentation, tissue perfusion, and ECG recordings were also assessed. RESULTS: 18 (75%) cats had low ionized calcium concentrations (reference range, 2.4 to 2.8 mEq/L). Hypocalcemia was considered mild (2.0 to 2.36 mEq/L) in 9 (37.5%) cats, moderate (1.6 to 1.98 mEq/L) in 6 (25%), and severe (< 1.6 mEq/L) in 3 (12.5%). Significant positive correlations were found between ionized calcium concentration and heart rate, pH, and concentrations of sodium, chloride, and total calcium. Significant negative correlations were found between ionized calcium concentration and concentrations of potassium, BUN, creatinine, and phosphorus. CLINICAL IMPLICATIONS: Most cats with urethral obstruction had a low concentration of ionized calcium. This may contribute to cardiac electrical and mechanical dysfunction in some severely affected cats. Although effects of i.v. administration of calcium were not evaluated, results of this study strengthen the rationale for its use in cats with urethral obstruction.     

粉末压片制样-波长色散X射线荧光光谱法测定直接还原铁中6种组分

直接还原铁中的Si、Al、P、Mg、Ca和S等杂质元素对钢的质量有重要影响,目前一般采用化学湿法分析和熔融制样-X射线荧光光谱法检测,程序相对繁琐。为缩短检测周期,研究采用粉末压片制样-X射线荧光光谱法测定直接还原铁中SiO₂、Al₂O₃、P、MgO、CaO和S,通过试验确定将淀粉作为粘结剂,在7.000 0 g样品中加入0.350 0 g淀粉,研磨120 s混匀并使其粒度小于0.074 mm,于30 t压力下压制成片。选取与待测试样组成、结构及粒度相似的具有一定梯度含量的直接还原铁标准样品/校准样品建立校准曲线,SiO₂、Al₂O₃、P、MgO、CaO和S校准曲线的线性相关系数分别为0.999、0.998、0.992、0.995、0.997和0.999。按照实验方法测定直接还原铁中SiO₂、Al₂O₃、P、MgO、CaO和S,结果的相对标准偏差(RSD,n=11)分别为0.014%、0.030%、0.076%、0.009%、0.026%和0.047%;分别采用实验方法与国家标准方法测定直接还原铁中SiO₂、Al₂O₃、P、MgO、CaO和S,结果相一致。方法满足进口直接还原铁样品的快速检测要求。     

粉末压片制样-波长色散X射线荧光光谱法测定直接还原铁中6种组分

直接还原铁中的Si、Al、P、Mg、Ca和S等杂质元素对钢的质量有重要影响,目前一般采用化学湿法分析和熔融制样-X射线荧光光谱法检测,程序相对繁琐。为缩短检测周期,研究采用粉末压片制样-X射线荧光光谱法测定直接还原铁中SiO₂、Al₂O₃、P、MgO、CaO和S,通过试验确定将淀粉作为粘结剂,在7.000 0 g样品中加入0.350 0 g淀粉,研磨120 s混匀并使其粒度小于0.074 mm,于30 t压力下压制成片。选取与待测试样组成、结构及粒度相似的具有一定梯度含量的直接还原铁标准样品/校准样品建立校准曲线,SiO₂、Al₂O₃、P、MgO、CaO和S校准曲线的线性相关系数分别为0.999、0.998、0.992、0.995、0.997和0.999。按照实验方法测定直接还原铁中SiO₂、Al₂O₃、P、MgO、CaO和S,结果的相对标准偏差(RSD,n=11)分别为0.014%、0.030%、0.076%、0.009%、0.026%和0.047%;分别采用实验方法与国家标准方法测定直接还原铁中SiO₂、Al₂O₃、P、MgO、CaO和S,结果相一致。方法满足进口直接还原铁样品的快速检测要求。     

Effectiveness of autologous blood replacement in rheumatoid arthritis surgery--a report of 10 years experience

The use of a wood stick (meswak or chewing stick) for brushing the teeth continues to be an important tool for oral hygiene care in many Afro-Asian communities. It is inexpensive, customary and used for religious reasons as well. Despite the wide use of meswak, information on its chemical and pharmaceutical contents are scant, particularly in regard to an anticaries effect. In the present study, sticks from Salvadora persica, the most common source for meswak, were analyzed for their soluble and total content of fluoride, calcium, phosphorus and silica. Results showed that the fluoride released from meswak soaked in water was negligible (< 0.07 microgram/ml). Approximately 39% of the total fluoride in the sticks was in a form that could be leached out. The leached calcium and phosphorus averaged 582 micrograms/ml and 34 g/ml, respectively, representing 19.6% and 26.4% of their total content in the sticks. There was a substantial amount of silica in the ashes of meswak. It appears that meswak is probably not particularly active against caries through its fluoride content, but it does act as a brush for removing dental plaque and polishing the teeth.