Magnesium gluconate offers no more protection than magnesium sulphate following diffuse traumatic brain injury in rats

OBJECTIVE: Previous studies have demonstrated that magnesium salts, including the sulphate and chloride forms, are neuroprotective following traumatic brain injury (TBI). Recently, studies in cardiac ischaemia/reperfusion injury have demonstrated that the gluconate salt of magnesium may provide superior protection against oxidative damage and postischaemic dysfunction than MgSO(4). We have therefore compared the efficacy of both MgSO(4) and magnesium gluconate (MgGl(2)) on outcome following diffuse TBI in rats. METHODS: Adult male Sprague-Dawley rats were injured using the 2-metre impact acceleration model of diffuse TBI. At 30 min after injury, animals were administered with either 250 micromoles/kg i.v. MgSO(4), MgGl(2), or equal volume saline vehicle. Thereafter, animals were assessed for motor and cognitive outcome using the rotarod and Barnes maze, respectively, or their brains removed at 3 days after TBI and used for histological examination. RESULTS: Treatment with either magnesium salt significantly improved functional outcome as compared to vehicle treated controls. Similarly, treatment with either magnesium salt attenuated the degree of histological dark cell change at 3 days after TBI relative to the vehicle treated animals. There were no significant differences between the magnesium treated groups. CONCLUSIONS: We conclude that MgSO(4) and MgGl(2) are equally neuroprotective following TBI. Our results suggest that MgGl(2) may only be more effective in conditions that produce ischaemia, where high concentrations of reactive oxygen species are generated.     

Optimal administration dosage of magnesium sulfate for torsades de pointes in children with long QT syndrome

BACKGROUND: Intravenous administration of magnesium sulphate (MgSO(4)) is a very effective and safe treatment for torsades de pointes (TdP) associated with acquired long QT syndrome (LQTS) in adults. Discussed here is the efficacy of MgSO(4) for TdP in children with congenital and acquired LQTS. METHODS: The optimal MgSO(4) dosage and serum magnesium (SMg) was determined in six consecutive children with TdP; four had congenital LQTS and two had acquired LQTS. A bolus injection of MgSO(4) was given intravenously over 1 to 2 minutes followed by continuous infusion for the next 2 to 7 days. RESULTS: Of the six patients, five responded completely to the initial bolus of 6.1 +/- 4.2 mg/kg (range, 2.3-12 mg/kg). One (a neonate with congenital LQTS) required a total of 30 mg/kg until complete TdP elimination. Continuous infusion was given at rates of 0.3 to 1.0 mg/kg/hr with no recurrence of TdP. SMg concentration was 3.9 +/- 1.0 mg/dL (2.9-5.4 mg/dL) immediately after bolus injection. CONCLUSION: Intravenous MgSO(4) infusion effectively treated TdP in children with LQTS. Optimal bolus dosage, infusion rates and SMg concentration were 3 to 12 mg/kg, 0.5 to 1.0 mg/kg/hr and 3 to 5 mg/dL, respectively.     

Self-administered subcutaneous fluid infusion at home in the management of fluid depletion and hypomagnesaemia in gastro-intestinal disease

BACKGROUND AND AIMS: In short bowel fistula and some other gastrointestinal (GI) diseases, salt, water and magnesium (Mg) balance may continue negative despite oral treatment, even in patients with adequate nutritional status. This study describes the use of self-administered subcutaneous fluid infusions (HSCF) to treat this problem. PATIENTS & METHODS: HSCF was administered to patients with GI failure and adequate macro-nutrient status (BMI) when GI salt, water and magnesium balance continued negative despite optimal diet, drug and supplemental treatment. Mg depletion was confirmed using the Mg load test. Patients were taught to self-administer 0.5-1.0 l 0.9% saline +/-0.5 l 5% dextrose +/-2-4 mmol MgSO4 subcutaneously by gravity drip during 6-12 h overnight, 3-7 days/week. Water and Na balance were assessed (weight, serum creatinine, urea, Na) at baseline and at 1 and 3 months of treatment, but also monitored carefully during the first few days of treatment. Serum Mg was measured at baseline and at 2 and 4 weeks. RESULTS: In 10 patients (mean age 65.3+/-13.5 years) Na and water balance was rapidly restored. At baseline, 1 and 3 months, serum biochemical results were: Eight patients received 8-28 mmol MgSO4/week in the infused fluid. Serum Mg [0.7-1.0 mmol] at baseline, 2 and 4 weeks was 0.49+/-0.06, 0.79+/-0.18, 0.83+/-0.10 mmol/l (P=0.002). Tolerance was good; transient oedema developed in 2 patients, resolved by reducing infusion dose. No patient developed hypokalaemia. CONCLUSIONS: Subcutaneous self-administered fluid infusion at home (HSCF) is an easily managed, safe and effective method of restoring and maintaining water, salt and Mg balance in patients with large GI fluid losses but adequate macronutrient status, particularly in the frail or elderly in whom home parenteral nutrition may be difficult.     

Influence of magnesium deficiency on liver collagen after carbon tetrachloride or ethanol administration to rats

The effects of magnesium deficiency on liver collagen after the administration of a hepatotoxic substance were investigated. Rats, fed a control or magnesium-deficient diet (0.040 g/kg), received six CCl4 or mineral oil injections administered at 2-d intervals starting from the first day of diet treatment. They were killed 3 or 12 d after the last injection. Between postinjection d 3 and 12, no change of magnesium concentration in liver was observed in the deficient rats. Three days after the end of treatment liver calcium in the magnesium-deficient CCl4-treated rats was higher than in any other group. Liver collagen of untreated control rats and untreated magnesium-deficient rats was not significantly different. In control and magnesium-deficient animals receiving CCl4 treatment, the liver collagen levels were significantly higher than in untreated rats. The magnesium-deficient rats receiving CCl4 have higher liver collagen than the controls receiving CCl4. In a second experiment the effect of suboptimum intake of magnesium (0.120 g/kg) combined with the ingestion of ethanol was studied in rats given a solution of ethanol in water for 55 d as their only source of fluid. Mortality occurred in the magnesium-deficient rats receiving ethanol, and body weights of these rats were lower than those of animals in the other three groups. The collagen concentration in liver was higher in magnesium-deficient rats consuming ethanol than in any other group. The synergistic action between magnesium deficiency and ethanol therefore appears to be analogous to that observed with CCl4.     

Magnesium sulphate and cervical ripening (a biomechanical double-blind, randomized comparison between a synthetic polyvinyl sponge with and without magnesium sulphate)

Lamicel is a commercially available synthetic polyvinyl sponge impregnated with magnesium sulphate (MgSO4), used to soften and dilate the cervix. To investigate whether magnesium sulphate contributes to the effect of Lamicel, forty-one pregnant nulliparous patients who underwent a first trimester abortion were allocated to three to four hours preoperative treatment with either Lamicel or the same type of tent without magnesium sulphate. The ripening effect on the cervix was measured biomechanically. Lamicel produced a cervical dilatation and ripeness equal to the syntetic tent without MgSO4. The two pretreated groups together showed a significantly (p less than 0.05) more favourable cervix compared to a control group of 40 patient.     

Daily magnesium supplements improve glucose handling in elderly subjects.

We demonstrated similar plasma concentrations and urinary losses but lower erythrocyte magnesium concentrations (2.18 +/- 0.04 vs 1.86 +/- 0.03 mmol/L, P less than 0.01) in twelve aged (77.8 +/- 2.1 y) vs 25 young (36.1 +/- 0.4 y), nonobese subjects. Subsequently, aged subjects were enrolled in a double-blind, randomized, crossover study in which placebo (for 4 wk) and chronic magnesium administration (CMA) (4.5 g/d for 4 wk) were provided. At the end of each treatment period an intravenous glucose tolerance test (0.33 g/kg body wt) and a euglycemic glucose clamp with simultaneous [D-3H]glucose infusion and indirect calorimetry were performed. CMA vs placebo significantly increased erythrocyte magnesium concentration and improved insulin response and action. Net increase in erythrocyte magnesium significantly and positively correlated with the decrease in erythrocyte membrane microviscosity and with the net increase in both insulin secretion and action. In aged patients, correction of a low erythrocyte magnesium concentration may allow an improvement of glucose handling.     

Therapeutic effect of magnesium on noise-induced hearing loss

This study examined the therapeutic effect of magnesium (Mg) on noise trauma in anesthetized guinea pigs exposed to an impulse noise series (1/s) of Lpeak 167 dB (Leq,1s 127 dB) for 38 min. The permanent hearing threshold shift (PTS) was measured 1 week post-exposure, using auditory brain stem response audiometry (frequency range, 0.5-32 kHz). The total Mg concentrations of perilymph, cerebrospinal fluid and plasma were analyzed by atomic absorption spectrometry. In a first series, animals maintained on physiologically low Mg received subcutaneous injections of either different Mg doses (0.11-0.33 mmol MgSO4/100 g per day) for 3 days and drinking water with an additive of 39 mmol MgCl2/l for 1 week or saline as a placebo and tap water alone. The treatment began immediately after the impulse noise exposure. The dose of 0.29 mmol Mg/100 g per day was found to be most effective and reduced the hearing loss by 13-20 dB compared to placebo. The PTS and the perilymph Mg level showed a close negative correlation, suggesting that the intracochlear Mg level plays an important role in bringing about these protective effects. In a second series, we tested the therapeutic efficacy as a function of the post-exposure time of onset of the optimal Mg treatment (1 min, 2 and 4 hours), using normal Mg animals. The therapeutic effect decreased with the length of time elapsed between the end of exposure and the beginning of treatment. In a parallel scanning electron microscopic test, we also found a Mg-related difference in the susceptibility of hair cell stereocilia to impulse noise exposure.     

Magnesium Gluconate Offers No More Protection than Magnesium Sulphate Following Diffuse Traumatic Brain Injury in Rats

Objective: Previous studies have demonstrated that magnesium salts, including the sulphate and chloride forms, are neuroprotective following traumatic brain injury (TBI). Recently, studies in cardiac ischaemia/reperfusion injury have demonstrated that the gluconate salt of magnesium may provide superior protection against oxidative damage and postischaemic dysfunction than MgSO₄. We have therefore compared the efficacy of both MgSO₄ and magnesium gluconate (MgGl₂) on outcome following diffuse TBI in rats.

Methods: Adult male Sprague-Dawley rats were injured using the 2-metre impact acceleration model of diffuse TBI. At 30 min after injury, animals were administered with either 250μmoles/kg i.v. MgSO₄, MgGl₂, or equal volume saline vehicle. Thereafter, animals were assessed for motor and cognitive outcome using the rotarod and Barnes maze, respectively, or their brains removed at 3 days after TBI and used for histological examination.

Results: Treatment with either magnesium salt significantly improved functional outcome as compared to vehicle treated controls. Similarly, treatment with either magnesium salt attenuated the degree of histological dark cell change at 3 days after TBI relative to the vehicle treated animals. There were no significant differences between the magnesium treated groups.

Conclusions: We conclude that MgSO₄ and MgGl₂ are equally neuroprotective following TBI. Our results suggest that MgGl₂ may only be more effective in conditions that produce ischaemia, where high concentrations of reactive oxygen species are generated.     

Identifying barriers to the availability and use of Magnesium Sulphate Injection in resource poor countries: A case study in Zambia

Background  

Pre-eclampsia and eclampsia are serious complications of pregnancy and major causes of maternal mortality and morbidity worldwide. According to systematic reviews and WHO guidelines magnesium sulphate injection (MgSO4) should be the first -line treatment for severe pre-eclampsia and eclampsia. Studies have shown that this safe and effective medicine is unavailable and underutilized in many resource poor countries. The objective of this study was to identify barriers to the availability and use of MgSO4 in the Zambian Public Health System.     

Magnesium attenuates post-traumatic depression/anxiety following diffuse traumatic brain injury in rats

OBJECTIVE: Magnesium (Mg) declines after traumatic brain injury (TBI), a decline believed associated with ensuing neuronal cell death and subsequent functional impairment. While Mg's effects on motor and cognitive deficits following TBI have been well studied, few studies have addressed post-traumatic depression as an outcome parameter, despite its being a major clinical problem with an incidence of between 6 and 77%. We investigated the incidence of post-traumatic depression/anxiety in an animal model of diffuse TBI, and explored the use of magnesium sulfate (MgSO(4)) as an interventional treatment. METHODS: Diffuse TBI was induced in 32 anesthetized, adult, male Sprague-Dawley rats, using the 2 m impact-acceleration model of injury. At 30 min after injury, half of the rats received 250 micromol/kg i.v. MgSO(4); the other half served as non-treated controls. Before and for 6 weeks after injury, the open-field, spontaneous activity test was used to determine post-traumatic depression/anxiety relative to pre-injury. In this test, animals are placed in a 1-meter square box with 100 squares marked on the base. The number of squares entered in a 5-min period is recorded. Incidence of post-traumatic depression/anxiety was defined as the number of animals demonstrating a reduction in spontaneous activity to less than 100 squares in 5 min. Prior to injury, rats typically entered a mean of 201 +/- 12 (SEM) squares over a 5 min observation period. RESULTS: At 1 week after injury, non-treated animals had a mean core of 62 +/- 13. The incidence of post-traumatic depression/anxiety in these animals was 61%, which is similar to that observed clinically. In contrast, animals treated with MgSO(4) had a mean activity score of 144 +/- 23 at 1 week after TBI and an incidence of depression/anxiety of less than 30%. The significant difference between groups persisted for the entire 6-week observation period. CONCLUSIONS: The improvement in post-traumatic depression/anxiety conferred by Mg adds further weight to available evidence of Mg's benefit as a neuroprotective agent after TBI.     

新生鼠缺氧缺血后脑髓鞘化观察及药物干预效果

目的 了解缺氧缺血对新生大鼠脑髓鞘化的影响及1-6二磷酸果糖(FDP)、硫酸镁(MgSO_4)、苯巴比妥(PB)3种药物急性期干预治疗的作用,评价早期治疗的疗效。方法 7日龄Wistar大鼠行左侧颈总动脉结扎,吸入8％氧气2h,立即腹腔注射FDP、MgSO_4、PB及生理盐水5d,于生后28d断头、取脑、冠状切片、行Luxol fast blue染色,计算机图象分析仪测量髓鞘染色平均吸光度和面密度。结果 缺氧缺血使新生大鼠脑髓鞘生成量减少,而成熟度未发生变化,3种药物均可使髓鞘生成量增加,但其作用不完全。结论 缺氧缺血影响了新生大鼠脑的髓鞘化,3种药物急性期干预治疗对神经纤维髓鞘化程度均有改善作用,而这种作用大多是不完全的。     

Inhibitory effect of dietary soybean protein vs. casein on magnesium absorption in rats

The effects of casein and soybean protein on magnesium absorption and magnesium concentration in the femur were investigated in rats. Purified diets containing either casein or soybean protein and three concentrations of added magnesium (0.82, 1.64 or 2.46 mmol/100 g diet) were used. The isonitrogenous diets were carefully balanced for the different mineral concentrations in the protein preparations. Absolute and percent magnesium absorption and urinary magnesium excretion were significantly decreased in rats fed soybean protein when compared with casein, irrespective of the dietary concentration of added magnesium. The magnesium content of femur was significantly lower in rats fed soybean protein, but this effect was seen only when the diet contained 0.82 mmol magnesium/100 g diet. The addition of sodium phytate to the casein diets, to a concentration identical to that in the diets containing soybean protein as provided by the soybean protein preparation, produced similar effects on magnesium absorption as the diets containing soybean protein. These results indicate that soybean protein, when compared with casein, decreases magnesium absorption through its phytate component.     

Effects of alfacalcidol on cancellous and cortical bone mass in rats treated with glucocorticoid: a bone histomorphometry study

The beneficial effects of alfacalcidol (ALF) on bone mass, bone formation, and bone resorption have been established in ovariectomized rats. Our previous studies showed that high-dose glucocorticoid (GC) administration (methylprednisolone sodium succinate, 5.0 mg/kg, s.c., 3 times a week) for 4 wk induced cancellous osteopenia without significantly affecting cortical bone mass in Sprague-Dawley rats, and that high-dose GC administration for 8 wk also resulted in cortical osteopenia. The purpose of the present study was to examine the effects of ALF on cancellous and cortical bone mass in GC-treated rats. Forty female Sprague-Dawley rats, 3 mo of age, were randomized by the stratified weight method into four groups of 10 rats each, as follows: age-matched control group (CON); 8-wk GC administration with administration of vehicle during the latter 4 wk of treatment (GC group); 8-wk GC administration with administration of a low dose of ALF (0.08 Ag/kg) during the latter 4 wk of treatment (low-dose ALF group); 8-wk administration of GC with administration of a high dose ofALF (0.16 microg/kg) during the latter 4 wk of treatment (high-dose ALF group). The GC (methylprednisolone sodium succinate, 5.0 mg/kg) was administered subcutaneously 3 times a week, and ALF was administered orally 5 times a week. At the end of the experiment, static and dynamic bone histomorphometric analyses were performed on cancellous bone of the proximal tibial metaphysis and cortical bone of the tibial diaphysis. Eight-week GC administration resulted in loss of the cancellous bone volume/total tissue volume (BV/TV) and percent cortical area (Ct Ar) as a result of decreased trabecular bone formation, increased trabecular and endocortical bone resorption, and decreased periosteal bone formation. Low-dose ALF restored the cancellous BV/TV by mildly suppressing bone resorption and restoring bone formation, whereas high-dose ALF increased it beyond the value observed in the age-matched controls by strongly suppressing bone resorption and markedly increasing bone formation. Both low- and high-dose ALF prevented the GC-induced reduction of the percent Ct Ar by increasing periosteal bone formation and suppressing endocortical bone resorption. The effects of ALF on cancellous bone mass, bone formation, and bone resorption were all dose-dependent. The present study showed the beneficial effects of ALF on cancellous and cortical bone mass in GC-treated rats.     

锌硒锰镁联合拮抗二氧化硅致肺泡巨噬细胞毒性的作用

[目的]观察葡萄糖酸锌（ZnG）、亚硒酸钠（Na2SeO3）、氯化锰（MnCl2）和硫酸镁（MgSO4）联合作用对二氧化硅（SiO2）致肺泡巨噬细胞（AM）中过氧化氢（H2O2）、丙二醛（MDA）、谷胱甘肽过氧化物酶（GSH—Px）、超氧化物歧化酶（SOD）、过氧化氢酶（CAT）水平变化的影响，寻找4者的最佳剂量组合。[方法]采用大鼠肺灌洗法纯化获得AM（1×10^9个／mL），同时加入SiO2及不同浓度的ZnG＋Na2SeO3＋MnCl2＋MgSO4溶液组合，另设不加组合溶液的SiO2对照组和阴性对照组。37℃，5％CO2培养箱培养18h后，检测上述5种指标。[结果]与SiO2对照组比较，ZnG、Na2SeP3、MnCl2与MgSO4联合使用均可明显降低AM中H2O2、MDA含量，升高GSH—Px、SOD和CAT的活性（P〈0．01），且以1．5mg／L的ZnG、1．0μmol／L的Na2SeO3、1．0mg／L的MnCl2、和0．5μmol／L的MgSO4联合作用效果最好。极差分析结果表明，对GSH—Px、SOD的影响，Na2SeO3的作用强于ZnG、MnCl2和MgSO4；对H2O2、MDA的影响，ZnG的作用强干Na2SeO3、MnCl2与MgSO4；对CAT的影响，MnCl2、ZnG的作用则要强于Na2SeO3与MgSO4。[结论]ZnG、Na2SeO3、MnCl2与MgSO4联合应用可明显拮抗SiO2粉尘所致AM的氧化损伤。     

Cyanidin 3-O-beta-D-glucoside attenuates the hepatic ischemia-reperfusion injury through a decrease in the neutrophil chemoattractant production in rats

We have shown that the orally administered cyanidin 3-O-beta-D-glucoside (C3G) attenuates the hepatic ischemia-reperfusion (I/R) injury, which was used as a model for oxidative stress through a decrease in neutrophil chemoattractant production in rats. The rats were subjected to hepatic I/R at 30 min after the administration of C3G (0.9 mmol/kg body weight) or vehicle. I/R treatment resulted in the elevation of oxidative stress marker [liver thiobarbituric acid-reactive substance, Nepsilon-(hexanonyl) lysine and dityrosine] levels in the liver and of the serum activities of marker enzymes for liver injury. The administration of C3G significantly suppressed these elevations, which had been caused by hepatic I/R. Liver myeloperoxidase activity, a useful marker for neutrophil infiltration into tissues, and the plasma and liver concentration of cytokine-induced neutrophil chemoattractant-1 (CINC-1), which has a potent chemotactic activity, were markedly elevated in the control group after hepatic I/R. However, these elevations were significantly suppressed in the C3G group. C3G and its metabolites in the plasma and liver were detected in the C3G group after hepatic I/R. These results suggest that the absorbed C3G and/or its metabolites can act as antioxidants in the blood and liver and scavenge the reactive oxygen species, and brought on a decrease in neutrophil infiltration into the liver through the suppression of CINC-1 production and the tissue damage caused by neutrophils after I/R is attenuated.     

Insulin-like growth factor-1 increases bone calcium accumulation only during rapid growth in female rats

Calcium retention varies with developmental state, which may be partially under the control of insulin-like growth factor 1 (IGF-1). IGF-1 levels can be manipulated through dietary and therapeutic interventions. We investigated the relationship between IGF-1 endogenous production and calcium utilization and bone accretion during growth as well as the effects of IGF-1 treatment on calcium utilization during rapid and slowed growth in intact female Sprague-Dawley rats. In 33 rats killed at 11 time points (n = 3 each) from age 4 to 24 wk, femoral and vertebral bone mass were paralleled by plasma IGF-1 up to 9 wk. Fractional calcium absorption was maximal at 9 wk, reduced by one-half at 12 wk, and there was no further change at 20 wk. From this study, we selected 2 stages of growth, rapid and slow, for a subsequent intervention study. A 4-wk intervention was initiated at 6 or 8 wk when rats (n = 15/group) received either continuous rhIGF-1/IGF binding protein 3 (IGFBP3) infusion (0.3 mg/d) or vehicle (control) by osmotic mini-pumps. In rapidly growing IGF-1/IGFBP3-treated rats compared to controls, but not in slowly growing treated compared to control rats, IGF-1 treatment increased (P < 0.05) calcium absorption (35 vs. 21%), bone calcium balance (0.55 vs. 0.3 mmol/d), and femoral calcium content (31 vs. 24% of dry weight). Exogenous IGF-1/IGFBP3 treatment increased calcium accretion during rapid growth, but rats past rapid growth were no longer as sensitive to this dose of IGF-1/IGFBP3. Thus, interventions designed to improve bone mass through increased IGF-1 will have the greatest impact during rapid growth.     

姜黄素对单纯性肥胖大鼠胰岛素抵抗及瘦素抵抗的影响

目的 探讨姜黄素对单纯性肥胖模型大鼠胰岛素抵抗及瘦素抵抗的影响.方法 初断乳雄性SPF级SD大鼠50只,按体重分层后随机分为2组.分别为高脂饲料喂饲组(30只),基础饲料喂饲组(20只).8周后观察比较体重变化.建模成功后,将肥胖模型大鼠按体重随机分为3组,分别为姜黄素高剂量组(5.00 g/kg)、姜黄素低剂量组(1.25g/kg)及肥胖模型对照组.基础饲料喂饲组按体重随机分为2组,分别为姜黄素高剂量对照组(5.00 g/kg)、基础对照组.每组各10只,各组动物均自由摄食基础饲料.灌胃给予不同剂量姜黄素4周后,检测体重、脂体比、血糖、胰岛素、瘦素、肿瘤坏死因子的影响及胰腺结构改变.结果给予姜黄素4周后,姜黄素高剂量组大鼠体重[(435.0±37.6)g]和体脂含量[(4.78±1.87)g]低于肥胖模型对照组大鼠体重[(492.3±14.8)g]和体脂含量[(8.94±1.88)g](t值分别为4.484和4.961,P值均＜0.01);姜黄素高剂量组大鼠血糖[(4.50±0.09)mmol/L]、胰岛素[(7.43±0.65)mmol/L]、瘦素[(3.40±0.39)mmol/L]及肿瘤坏死因子水平[(2.42±0.19)ng/nd]低于肥胖模型对照组大鼠血糖[(4.94±0.12)mmol/L]、胰岛素[(9.30±0.21)mmoL/L]、瘦素[(4.40±0.23)mmol/L]及肿瘤坏死因子水平[(2.86±0.49)ng/ml],(t值分别为8.297、7.743、6.247、2.368,P值均＜0.05);且血糖水平与基础对照组[(4.30±0.14)mmol/L]差异无统计学意义(t=0.399,P＞0.05).超微结构观察显示,给予姜黄素后,胰岛β细胞内含有大量的分泌颗粒,颗粒多呈圆形,颗粒内电子密度较高,颗粒外有较大的空隙.结论姜黄素可通过减轻胰腺组织脂肪沉积,使胰岛素淋巴回流畅通,抑制胰岛细胞的凋亡,而有效缓解肥胖引起的胰岛素抵抗和瘦素抵抗.     

Magnesium, calcium, zinc, and nitrogen loss in trauma patients during continuous renal replacement therapy

BACKGROUND: Whether standard nutrition support is sufficient to compensate for mineral loss during continuous renal replacement therapy (CRRT) is not known. METHODS: Adult men with traumatic injuries were recruited; one-half of recruits required CRRT for acute renal failure. All urine and effluent (from CRRT) were collected for 72 hours. Urine, effluent, and dialysate were analyzed for magnesium, calcium, and zinc using atomic absorption spectrometry. Urea nitrogen in blood, urine, and effluent were determined by measuring conductivity changes after the addition of urease. Blood was analyzed for magnesium and calcium as part of routine care. Intake was calculated from orders and intake records. RESULTS: Patients receiving CRRT (n = 6) lost 23.9+/-3.1 mmol/d (mean +/- SEM) of magnesium and 69.8+/-2.7 mmol/d of calcium compared with 10.2+/-1.2 mmol/d and 2.9+/-2.5 mmol/d, respectively, lost in patients not in acute renal failure (n = 6; p < .01). Zinc intake was significantly greater than loss in both groups (p < .03). Urea nitrogen excretion did not differ between groups. Serum magnesium was 0.75+/-0.04 mmol/L for CRRT patients, significantly lower than the 0.90+/-0.03 mmol/L for control patients (p < .01). Total blood calcium was below normal in both groups; ionized calcium was below normal in CRRT patients. CONCLUSIONS: CRRT caused significant loss of magnesium and calcium, necessitating administration of more magnesium and calcium than was provided in standard parenteral nutrition formulas. However, additional zinc was not required. CRRT removed amounts of urea nitrogen similar to amounts removed by normally functioning kidneys.     

Magnesium sulfate loading: preeclampsia vs preterm labor (a clinical pearl).

To measure the apparent volume of distribution (AVOD) for magnesium (Mg) in preeclampsia and preterm labor and determine if a standard 4 gm loading dose of magnesium sulfate (MgSO4) is sufficient to attain therapeutic levels.

Twenty-five patients with preeclampsia and 25 with preterm labor received 4 g of MgSO4 intravenously over 15 minutes. Serum Mg levels were determined before and one minute after loading and the AVOD for Mg was calculated. Stepwise linear regression with AVOD as the dependent variable was performed and comparisons between the groups were made.

Preeclamptics were heavier, had greater surface areas, and presented at a later stage of pregnancy than did patients with preterm labor. Despite these differences AVOD did not differ between the groups. Predose magnesium levels were slightly higher in the preeclamptic group (p = .04). Post-loading levels were nearly identical due to similar AVOD's and, because of the lower levels required for seizure prevention as opposed to tocolysis, were therapeutic 88% of the time in preeclampsia but only 12% of the time in preterm labor (p < .001). Multivariate analysis revealed that only ideal body weight, degree of underweight, and current therapy with betamimetics were significantly related to AVOD.

AVOD was found to be similar in preeclamptic and preterm labor patients. A 4 g loading dose of MgSO4 is usually adequate to achieve therapeutic levels in preeclampsia but not in preterm labor.     

复方丹参对重度妊高征肾功能的影响

目的:探讨复方丹参于预给药治疗重度妊高征对孕妇肾功能的影响。方法:将80例重度妊高征患者分为:重度妊高征40例为Ⅰ组,重度妊高征并发肾功能异常40例为Ⅱ组。每组又随机分为复方丹参治疗组、硫酸镁对照组。Ⅰ组检测治疗前、后内皮素含量;Ⅱ组检测肾功能变化。结果:经复方丹参治疗后血浆内皮素含量明显低于硫酸镁对照组(P<0.05);肾功能变化:复方丹参治疗组术后Cr、BUN浓度皆明显低于硫酸镁对照组;从治疗前及术后24 h Cr、BUN的变化可以看出:复方丹参治疗组术后20例有1例恶化;而硫酸镁组术后20例有7例恶化(P<0.05)。结论:复方丹参治疗重度妊高征,有利于病情控制,延长孕周,能减轻损伤的肾功能术后灌注再损伤。改善妊高征患者母儿预后。