偶氮胂Ⅲ测定血清镁

目的 :建立简便、灵敏的偶氮胂Ⅲ (ArsenanoⅢ )血清镁测定法。方法 :在碱性条件下 ,用EGTA消除钙的干扰 ,偶氮胂Ⅲ与镁离子形成蓝紫色络合物 ,以分光光度法测定血清镁。结果 :偶氮胂Ⅲ -镁反应液的最大吸收峰为 6 15nm ,反应最适pH8 8,偶氮胂Ⅲ最适浓度为 15 0umol/L ,EGTA加入量为 2 0 0umol/L。本法批内CV及批间CV(n =2 0 )分别为 1 70～ 2 10 %、2 17～ 2 5 7%。平均回收率为 99 3% ,线性 0～ 3 0mmol/L。胆红素 (5 0 0umol/L以内 ) ,血红蛋白 (7g/L)。脂肪乳剂Interlipid(4g/L)对测定无干扰。该法与MTB法对照 ,结果无显著差异。 (P >0 0 5 )。结论 :偶氮胂Ⅲ测定血清镁简便、快速、灵敏、可靠 ,适于手工分析和自动化分析     

Plasma ionized magnesium in tubular disorders with and without total hypomagnesemia

 Selective electrodes have been designed for determining plasma ionized magnesium. In kidney disease the relationship between ionized and total circulating magnesium is often altered. Hence plasma ionized magnesium (ETH 7025 membrane) was determined in 25 patients with primary renal tubular disorders; 6 patients had total hypomagnesemia. Total plasma magnesium was never reduced in the remaining 19 patients. Plasma ionized magnesium values were low in the 6 patients with total hypomagnesemia. In 18 of the 19 patients without total hypomagnesemia plasma ionized magnesium values were not reduced. Ionized hypomagnesemia was noted in a patient with normal total plasma magnesium in the context of hypercalciuric nephrocalcinosis of unknown origin. The study demonstrates an excellent concordance between plasma total and ionized magnesium in tubular disorders associated with total hypomagnesemia and a good concordance in tubular disorders that are not linked with total hypomagnesemia. The determination of circulating ionized magnesium is of little value in the diagnostic work-up of the vast majority of renal tubular disorders. The determination might perhaps disclose latent hypomagnesemia in nephrocalcinosis of unknown cause. Received: 20 March 1998 / Revised: 28 May 1998 / Accepted: 29 May 1998     

Competitive adsorption of magnesium and calcium ions onto synthetic and biological apatites

Summary Magnesium (Mg) is a conspicuous constituent of hard tissues but its possible role in biomineralization is poorly understood. It is possible that Mg²⁺ adsorbed onto bioapatites may contribute to the modulation of crystal growth as such inhibitory activity has been reported for synthetic apatites. The present study was undertaken to determine the adsorption isotherms of Mg ions onto synthetic apatites and biominerals in tooth and bone tissues in the presence of other ions of natural occurrence. Synthetic crystals used as adsorbents were hydroxyapatite and, as a better prototype for the biomineral, Mg-containing carbonatoapatite. Human enamel and dentin materials were obtained from extracted, caries-free, permanent teeth. Porcine dentin materials at two developmental stages were obtained from erupted deciduous and unerupted permanent teeth of a 6-month-old slaughtered piglet. Porcine bone was obtained from the cortical portion of the mandible of the same animal. All biomineral samples were pulverized and then treated by plasma ashing (deproteination) at about 60°C. Each of the powdered samples was equilibrated in solutions containing various initial concentrations of Mg²⁺, Ca²⁺, and Na⁺ (or K⁺) as nitrate salts. Following equilibration, concentrations (and activities) of magnesium and calcium ions in the experimental solution were determined. The pH values of the equilibrium solutions were in the range of 6.2–6.5. Experimental data of the Mg adsorption onto hydroxyapatite were interpreted on the basis of a Langmuir-type model for binary systems assuming competition of Mg²⁺ and Ca²⁺ for the same adsorption sites on the crystal surfaces of the apatites. According to this model, the adsorbed Mg is expressed as a function of the ionic activity ratio (Mg²⁺)/(Ca²⁺) in the equilibrium solution. The model contains two parameters, the adsorption selectivity constant K_s and the maximum number of adsorption sites N (mol/g). The numerical values of K_s were similar for all adsorbents used (synthetic and biological) and indicated the preferential adsorption of Ca²⁺ probably due to spacial restrictions extending to the very surface of the crystals. The initial level of Mg²⁺ in the surface pool was different in the various biominerals, probably reflecting the composition of fluid in which the biominerals were formed. Whereas the surface pool of Mg of human enamel was marginal, only 5% of the total Mg, significant fractions of the total Mg in human and porcine dentins (about 20–30%), and porcine bone (about 40%) existed on the crystal surfaces. There were significant differences in the total Mg and the value of the parameter N between young (unerupted) and mature (erupted) dentin minerals. It was ascertained that the occupancy of adsorption sites by Mg ions became greater with maturation of the dentin tissues. The overall results suggest that the Mg-mineral interaction in tooth and bone tissues may be a highly tissue-specific process, presumably reflecting differences in fluid composition (particularly Ca and Mg activities) responsible for biomineralization.     

镁离子对脑保护作用的前瞻性临床实验研究

目的探讨分析镁制剂在重型颅脑损伤临床治疗中的实用价值.方法对76例重型颅脑损伤患者按随机方法分成实验组和对照组,对照组按常规方法治疗,实验组在常规治疗的基础上加用大剂量硫酸镁.治疗后从颅内压、NSE、CT、GCS评分和G0S评级等几个方面进行统计分析.结果实验组与对照组比较,颅内压和NSE水平明显下降,CT显示脑水肿程度减轻,而GCS和G0S则有明显提高,经统计学检验有显著性差异(P＜0.01和P＜0.05).结论镁制剂对重型颅脑损伤治疗确有实用价值,且经济、安全,值得推广.     

镁与新生儿缺氧缺血性脑病:附55例临床分析

目的:探讨镁与新生儿缺氧缺血性脑病的关系。方法:随机选择HIE病例55例和对照组25例,将其入院后第一次血清镁测量值进行对比,结果进行u检验。结果:血清镁HIE组为(0.65±0.14)mmol/l,对照组为(0.80±0.09)mmol/l,P<0.01。结论:新生儿缺氧缺血性脑病有低镁倾向,且病情程度越重,血镁降低越明显。     

高频振荡通气及联合硫酸镁治疗新生猪重症胎粪吸入综合征的实验研究

目的　探讨高频振荡通气 (HFOV)及联合硫酸镁 (Mg SO4 )治疗合并持续肺动脉高压(PPH)的重症胎粪吸入综合征 (MAS)模型氧合、循环功能 ,血镁浓度及肺组织病理改变。　方法　以2 0 %胎粪混悬液制备重症 MAS模型 ,健康新生猪随机分为 3组 ,即模型 HFOV治疗组 (HFOV组 ,n= 6 ) ,HFOV+Mg SO4 治疗组 (HFOV+Mg SO4 组 ,n=7) ,HFOV对照组 (对照组 ,n=5 ) ,HFOV+Mg SO4 组同时静脉持续泵入 Mg SO4 。监测生命体征、血气、血镁浓度。　结果　 (1) HFOV和 HFOV+Mg SO4 治疗均使 MAS模型动脉血氧分压 (Pa O2 )、动脉血氧 /肺泡血氧分压比 (a/ APO2 )增加 ,肺泡-动脉血氧分压差 (A- a DO2 )、肺内分流 (Qs/ Qt)降低 ,治疗 30 min与治疗前比差异有非常显著性 (P<0 .0 1)。HFOV组各时间点 Pa O2 、a/ APO2 低于对照组 ,A- a DO2 、Qs/ Qt高于对照组 (P<0 .0 5 )。HFOV+Mg SO4 组治疗 12 0 m in后上述指标与对照组差异无显著性 (P>0 .0 5 )。 (2 )尽管氧合功能改善 ,单独 HFOV对重症 MAS的 PPH无降低作用 ,联合 Mg SO4 治疗 30 min即可有效降低 PPH(P<0 .0 5 ) ,并保持疗效。(3) HFOV组较 HFOV+Mg SO4 组有明显肺出血 ,出血沿肺段、小叶分布 ,两组病理评分差异有显著性 (P<0 .0 5 )。 (4) HFOV+Mg SO4 组血镁浓度较治疗     

Calcium-phosphorus-magnesium homeostasis in pregnant women after renal transplantation.

OBJECTIVE: The aim of the study was the assessment of calcium-phosphorus-magnesium homeostasis in pregnant women after renal transplantation. METHODS: The study covered 64 pregnant women in the third trimester of gestation including: 33 women after renal transplantation (the study group) and 31 healthy pregnant women (the control group). Women from both groups were at the similar age: 30.8+/-4.7 vs. 31.3+/-5.0 years (NS) and at the same gestational age 34.8+/-2.4 vs. 35.3+/-2.6 weeks (NS). The mean body mass index (BMI) in the women from the study group before pregnancy was 21.49+/-2.81 vs. 22.1+/-3.02 in the control group (NS), BMI before delivery was 25.43+/-3.05 vs. 26.0+/-3.35 (NS), the percentage of the BMI increase during pregnancy was 18.7+/-7.68 vs. 17.65+/-7.13 (NS) and BMI increase during gestation was 3.93+/-1.56 vs. 3.90+/-1.54, respectively (NS). Arterial blood pressure at the time of blood samples collection for biochemical tests was 151.4+/-26.8/92.5+/-16.9 in women from the study group comparing to 115.0+/-6.0/68.0+/-7.0 mmHg (P<0.001) in the patients from the control group. The maximal blood pressure during pregnancy was 169.2+/-20.7/102.7+/-14.0 vs. 118.0+/-7.0/70.0+/-8.0 mmHg (P<0.001), respectively. We estimated serum levels of: total Ca, ionized Ca(2+), inorganic phosphorus (P(i)), Mg, total protein, albumin and blood morphology. Moreover, urine levels of Ca, P(i), Mg and protein were assessed. RESULTS: The pregnant women after renal transplantation presented increases in serum concentrations of total Ca (2.54+/-0.20 vs. 2.16+/-0.10 mmol/l; P<0.001) and ionized Ca(2+) (1.322+/-0.104 vs. 1.12+/-0.07 mmol/l; P<0.001) and the decrease in P(i) level (1.013+/-0.211 vs. 1.10+/-0.16 mmol/l; P<0.05), total protein (59.3+/-7.0 vs. 65+/-5 g/l; P<0.001) and albumin (461.6+/-65.65 vs. 493.2+/-59 micromol/l; P<0.05). Moreover, in the study group drop in red blood cells count to 3.71+/-0.56 vs. 4.01+/-0.35 x 10(12)/l (P<0.02) in the control group was detected. Despite increased volume of 24-h urine collection in the kidney recipients we observed significantly decreased urine 24-h calcium excretion 2.47+/-0.92 vs. 6.72+/-3.49 mmol (P<0.001) and simultaneous increase in urine Mg excretion 3.422+/-1.025 vs. 2.18+/-0.52 mmol/24 h (P<0.001). There was no difference in urine 24-h P(i) excretion between the study and the control group. The pregnant renal transplant recipients presented proteinuria of 1.19+/-1.9 g/24 h. CONCLUSIONS: Women after kidney grafting present vital aberrations in calcium-phosphorus-magnesium homeostasis during pregnancy. The most significant changes are associated with calcium metabolism (high increase in serum Ca levels and impairment of renal elimination of calcium). The observed changes may be influenced by the doses of immunosuppressive agents and disturbed renal function.     

提高稀释液浓度测定硫酸卡那霉素含量

目的：探讨按中国药典（2000年版）抗生素微生物检定法测定硫酸卡那霉素含量的最后稀释液浓度范围；方法：应用ZY－300IV型抗生素抑菌圈面积测量分析仪，测定硫酸卡那霉素抑菌圈面积与对数剂量的线性关系范围；结果：测定硫酸卡那霉素含量时，最后稀释液浓度范围在5.5-20.4IU/ml内对数剂量与抑菌圈面积呈直线关系。     

高效液相色谱法测定复方吲哚美辛栓中硫酸沙丁胺醇的含量

目的 :建立 HPL C法测定复方吲哚美辛栓中硫酸沙丁胺醇的含量。方法 :采用 Dinamonsil C1 8柱 ,5 μm,4 .6 mm×2 0 0 mm;流动相 :磷酸二氢钠溶液 (用磷酸调 p H3.10± 0 .0 5 ) -甲醇 (85∶ 15 ) ,流速 1.0 ml·min- 1 ,检测波长 2 2 4 nm。结果 :硫酸沙丁胺醇在 9.6～ 38.4μg· ml- 1 范围内呈良好的线性关系 ,r=0 .99997,回收率为 99.95 %。结论 :该法快速、灵敏、准确。