Pregnancy in SLE

The effect of pregnancy on disease activity in systemic lupus erythematosus remains controversial. Studies on lupus flares in pregnancy are discussed, including prospective data on severity of flares and organ involvement from the Hopkins Lupus Pregnancy Center. The major fetal concerns of miscarriage (due to the antiphospholipid antibody syndrome), pre-term birth (largely due to pre-eclampsia or premature rupture of membranes) and neonatal lupus, are reviewed.     

Efficacy and safety of nifedipine versus magnesium sulfate in the management of preterm labor: a randomized study

OBJECTIVE: Our purpose was to establish the efficacy and safety of nifedipine versus magnesium sulfate in arresting preterm labor and the efficacy of nifedipine versus terbutaline in preventing recurrent labor. STUDY DESIGN: Singleton pregnancies at < 34 weeks in preterm labor were randomized to either oral nifedipine or intravenous magnesium sulfate. In case of tocolysis failure ritodrine was added. After labor was arrested, the patients in the nifedipine group were maintained on oral nifedipine, and those in the magnesium sulfate group were treated with oral terbutaline until completing 34 weeks. RESULTS: Of 100 patients 80 were considered eligible, of whom 39 were randomized to the nifedipine group. Both groups were comparable in terms of a number of entry variables, including cervical examination, contraction frequency, and gestational age. Both drugs were equally effective in arresting labor and delaying delivery > 48 hours, 92% versus 93%. Both study groups had a similar incidence of side effects, although four (10%) of magnesium sulfate-treated patients required drug discontinuation because of severe symptoms. Nifedipine was as effective as terbutaline in preventing recurrent labor, 26% versus 24%, and in achieving a gestation > 34 weeks, 62% versus 68%. CONCLUSIONS: Oral nifedipine is as effective as magnesium sulfate and terbutaline in arresting and preventing idiopathic preterm labor.     

Adjustment of magnesium sulfate infusion rate in patients with preterm labor

OBJECTIVE: Our purpose was to investigate factors that might influence serum magnesium levels during intravenous magnesium sulfate tocolytic therapy. STUDY DESIGN: Thirty-three women receiving magnesium sulfate for preterm labor participated in this prospective, observational study. Gestational ages were 24 to 34 weeks. Four groups of women were identified according to the maintenance magnesium infusion rate required for arresting preterm labor after 5 g of therapy induction: 1.5, 2, 2.5, and 3 g/h. Serum magnesium samples were drawn after a predefined period of at least 18 hours of arrested preterm labor, at a minimum of every 6 hours. Variables examined included serum albumin; serum protein; serum ionized calcium; serum creatinine; creatinine clearance; 24-hour urine output; maternal height, weight, body surface area; and body mass index. RESULTS: By use of a multivariate stepwise regression model we identified four variables that independently and significantly contributed to the model: magnesium infusion rate (P < .001); total serum protein level (P < .001); serum creatinine level (P = .009); and maternal weight squared (P = .026). Seventy-two percent of the variance was accounted for by use of these parameters. A predictive linear model, developed to relate these factors, produced the following formula: Suggested magnesium infusion rate = 0.89 x Serum magnesium concentration (mg/dL) - 3.16 x Serum creatinine (mg/dL) - 0.66 x Serum total proteins (g/dL) + 0.0001 x (maternal weight)2 (kg) + 2.30. CONCLUSIONS: Serum creatinine, serum protein, and maternal weight can be used to adjust the dose of magnesium sulfate in patients with premature labor to achieve therapeutic serum levels of magnesium more rapidly and safely.     

Effects of intravenous magnesium sulfate on arrhythmias in patients with congestive heart failure

Intravenous magnesium is an effective treatment for ventricular tachycardia of some etiologies, and in patients with congestive heart failure low serum magnesium concentrations are associated with frequent arrhythmias and high mortality. This suggests that magnesium administration may decrease the frequency of ventricular arrhythmias in patients with heart failure. We therefore assessed the impact of an intravenous magnesium infusion upon the frequency of ventricular premature depolarizations in 40 patients with New York Heart Association (NYHA) class II to IV heart failure and serum magnesium < or = 2.0 mg/dl. Within 1 week of a baseline 6-hour ambulatory electrocardiographic recording, an infusion of 0.2 mEq/kg of MgSO4 was given over 1 hour and a repeat 6-hour recording was obtained. There was an inverse relationship between the change in magnesium concentration and the change in frequency of premature ventricular depolarizations; premature ventricular depolarizations declined by 134 +/- 207 hr-1 in patients in whom serum magnesium concentration increased > or = 0.75 mg/dl, but increased by 72 +/- 393 hr-1 in patients with a change < 0.75 mg/dl (p < 0.05). For all patients, the frequency of premature ventricular depolarizations was 283 +/- 340 hr-1 pretreatment and 220 +/- 269 hr-1 following magnesium infusion (p = 0.21). Patients with > or = 300 premature ventricular depolarizations hr-1 demonstrated a decrease from 794 +/- 309 to 369 +/- 223 hr-1 (p < 0.001). Intravenous magnesium administration decreased the frequency of couplets from 233 +/- 505 to 84 +/- 140 (p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)     

Are there still indications for cerclage in 1995?

AIM: In order to assess their undertook a retrospective study in their department over a 4 year period: from January 1991 to December 1994. METHOD: the study concerned 129 patients who were treated by cerclage. This procedure was performed prophylactically in the great majority of them (97), while it was carried out as an emergency in 32 (25%). RESULTS: the authors drew a distinction between two groups (prophylactic and emergency suture) when analyzing the various results: complications due to suture, mean age of pregnancy at delivery, threatened premature labor, mean length of prolongation obtained. These personal data formed the basis of a review of the literature, in order to specify the indications for suture adopted by various authors at the present time. CONCLUSION: the authors found themselves to be in agreement with data from the literature, considering a history of at least two obstetric accidents (late abortions) and/or the existence of a severe uterine malformation to be the principal indication for prophylactic suture. "Emergency" suture should be performed whenever there is a serious threat of early premature labor in the presence of cervical changes such that suture offers the only chance of prolonging the pregnancy.     

Diazepam: routes of administration and rate of absorption. A study of women with pre-eclampsia

Plasma diazepam concentrations were determined following oral, i.m. and i.v. administration to a group of pregnant women with pre-eclampsia and a group of normal pregnant women. Diazepam concentrations were greater following oral as compared with i.m. administration in the control group, who received a single 5-mg dose, and this confirms previous similar reports. In the patients with pre-eclampsia, who were pre-loaded with diazepam, the i.m. route provided much higher plasma diazepam concentrations than did the oral route. This was probably a result of reduced gastric motility and gastric secretion caused by diazepam which affected the absorption of subsequent diazepam administered orally, and it is unlikely that pre-eclampsia contributed to these differences. Mist. magnesium trisilicate seemed to improve the rate of absorption of diazepam from the intestine in five patients studied, although this effect is unlikely to have much clinical importance.     

红土镍矿HCl浸出液中Mg的回收和浸出剂再生

简述了近年来红土镍矿HCl浸出液中Mg的回收及浸出剂再生工艺的研究现状,介绍了对浸出液采用MgCl_2溶液的水解、硫酸盐水合物的结晶、碱式MgCl_2的沉淀、纳米级Mg(OH)_2的制备以及MgCl_2溶液的雾化干燥与焙烧等处理方法和应用进展.     

Nutritional interventions for the prevention of maternal morbidity

OBJECTIVE: To review the effectiveness of nutritional interventions to prevent maternal morbidity. METHODS: This is an overview of systematic reviews and individual randomized controlled trials (if no systematic review available) of nutritional interventions during pregnancy. For each nutrient intervention the main maternal morbidity data reported were extracted. These were pre-eclampsia/eclampsia, pregnancy-induced hypertension, hemorrhage, anemia, infection and obstructed labor. In addition, the trial settings, the number of trials and participants' characteristics were systematically extracted. RESULTS: The systematic reviews considered in this paper had only few trials that reported the selected maternal outcomes. Outcome measures are based sometimes on one trial only. Most of the interventions compared single micronutrient supplementation with placebo/no treatment and did not show significant benefits for the supplementation groups. Calcium supplementation in women at high risk of pregnancy hypertension reduced the incidence of high blood pressure (RR, 0.35; 95% CI, 0.21-0.57) and pre-eclampsia (RR, 0.22; 95% CI, 0.11-0.43). Similarly, in women with low dietary calcium intake, calcium supplementation resulted in a significant reduction in the incidence of high blood pressure (RR, 0.49; 95% CI, 0.38-0.62) and pre-eclampsia (RR, 0.32; CI, 0.21-0.49). In women at low risk of pregnancy hypertension or with adequate baseline calcium intake, the beneficial effects of calcium supplementation are small and unlikely to be of clinical significance. Both, iron and folate supplementation reduced the number of women with low pre-delivery hemoglobin. CONCLUSIONS: Routine calcium supplementation seems to be a promising intervention for pregnant women at risk of developing preeclampsia or have low calcium intake, but these findings need to be confirmed with a trial with adequate power in different settings. In populations with high incidence of nutritional anemia routine iron and folate supplementation should be recommended during ante-natal care. It is unclear at this stage if adding vitamin A to iron and folate supplementation in anemia prevalent areas provides further benefits. There is inadequate data on the benefits or harms of routine iron or folate supplementation in adequately nourished populations. With regard to other micronutrient supplementation, such as zinc, magnesium and fish oil, randomized controlled trials with sufficient power to detect clinically important differences in maternal and infant outcomes are needed.     

The pharmacological prevention of pre-eclampsia

The disparate results reported in the literature on the effects of low dose aspirin in preventing pre-eclampsia might be caused by non-compliance in the more recent large trials in low-risk patients. All the earlier small trials were done on identified high-risk patients who consider themselves as patients, as do their doctors. Compliance in these patients will be very high. In fact, the only study in healthy subjects in which aspirin intake was controlled for (Hauth et al 1993) showed a marked reduction in the incidence of pre-eclampsia. However, the recent large trials have demonstrated, without any doubt, that low dose aspirin is not a miracle drug. The combined literature points at a 25% reduction in the incidence of pre-eclampsia in association with the use of aspirin (Collins, 1994). The correct indication for the use of low-dose aspirin appears to be the patient that is at very high risk of developing early-onset (less than 32 weeks gestation) pre-eclampsia. Since early-onset pre-eclampsia can begin at any time after 20 weeks gestation, it is necessary to initiate low-dose aspirin therapy early in pregnancy, preferably at 10-14 weeks gestation. The results of the recent large trials emphasize the need for a reliable, sensitive method of predicting or detecting pre-eclampsia at a very early gestational age (Dekker and Sibai, 1991). Valensise et al (1993) recently confirmed earlier studies (McParland et al, 1990) on the useful combination of uteroplacental Doppler flow velocimetry and aspirin in low-risk primigravidae. Results from current large-scale trials, such as the ECPPA, the BLASP, the WHO Jamaica and the second NICHHD studies, will be available in the near future. The results of especially the second NICHHD study on low-dose aspirin, in more than 2000 high-risk women (previous pre-eclampsia/eclampsia, chronic hypertension, class B to F diabetes or multiple gestation), will hopefully give us a more definitive picture on the potential benificial effects of low-dose aspirin in high-risk patients. The effect of aspirin on placental TXA2 deserves further studies. It might be that the optimal level to inhibit placental TXA2 and lipid peroxide production is actually higher than the minimal effective doses of aspirin that are needed to inhibit platelet TXA2 production (Walsh, 1994). Low-dose aspirin appears to be safe for the fetus and neonate. If there is an increased risk of abruptio placentae, this risk appears to be minimal. The final word on the use of low-dose aspirin has not yet been reached; however, we may be getting closer to profiling patients for whom the therapy may be efficacious and beneficial to both mother and fetus. Further studies are also necessary on combinations of aspirin and other antithrombotic drugs, such as heparin or ketanserin (Tanaka et al, 1993; Bolte et al, 1994; North et al, 1994). North et al (1994) demonstrated that treatment of women with severe renal disease with heparin plus aspirin reduced the prevalence of superimposed pre-eclampsia, compared with no treatment or aspirin alone. Next to low-dose aspirin, there appear to be several new and promising pharmaceutical approaches for reducing the consequences of EC dysfunction. Among these are selective TXA2-synthetase or TXA2-receptor antagonists, Serotonin2-receptor blockers, stable PGI2 analogues and NO donors.     

Gd-DTPA enhanced multi-shot echo-planar MRI: improvement of contrast between metastatic liver cancer and liver parenchyma

Budd-Chiari syndrome is a rare and serious thrombotic event with significant morbidity and mortality. Recommendations regarding future conception and management during pregnancy have not been defined. We present a patient with history of idiopathic Budd-Chiari Syndrome and subsequent orthotopic liver transplantation who was successfully managed during pregnancy. A 24-year-old white female, gravida 1 para 0, status postorthotopic liver transplantation 5 years previously for Budd-Chiari syndrome with post-transplant insulin-dependent diabetes mellitus presented to our clinic at 7 weeks of gestation for initial prenatal evaluation. Maintenance immunosuppressive therapy and prophylactic heparin anticoagulation was administered throughout the pregnancy, which was uneventful until 35 weeks gestation, at which time pre-eclampsia and premature preterm rupture of membranes prompted labor induction. The patient developed no evidence of acute or chronic hepatic rejection and no evidence of recurrent Budd-Chiari syndrome during the pregnancy or post-partum convalescence. Prudent use of prophylactic anticoagulation, close immunosuppressive monitoring, and periodic fetal and maternal surveillance are warranted in patients with previous orthotopic liver transplantation for idiopathic Budd-Chiari syndrome and may reduce risk of recurrence during pregnancy.     

Maternal placental vasculopathy and infection: two distinct subgroups among patients with preterm labor and preterm ruptured membranes

OBJECTIVE: Our aim was to find out whether patients delivered preterm because of preterm labor or preterm premature rupture of membranes can be categorized according to clinical characteristics and placental pathologic findings. STUDY DESIGN: We performed a case-control study of 105 patients who were delivered preterm, 42 because of preterm labor and 63 because of premature rupture of membranes, and 105 patients who were delivered at term after uncomplicated pregnancies. RESULTS: Maternal placental vascular lesions were present in 14 (34.1%) patients with preterm labor, 19 (35.1%) patients with premature rupture of membranes, and 9 (11.8%) control patients (odds ratios 3.8 and 4.0, 95% confidence intervals 1.3 to 11.1 and 1.5 to 10.8, p = 0.0065 and 0.0022, respectively). Infection of the products of conception was found in 16 patients (38%) with preterm labor, 23 patients (36.5%) with premature rupture of membranes, and 19 control patients (18%) (odds ratios 2.7 and 2.6, 95% confidence intervals 1.1 to 6.6 and 1.2 to 5.6, p = 0.017 and 0.01, respectively). Patients with maternal placental vasculopathy had significantly different characteristics compared with those of infected patients. CONCLUSIONS: It is possible to identify two subgroups of patients among those who are delivered preterm because of preterm labor or premature rupture of membranes, one with infection of the products of conception and another with maternal placental vasculopathy.     

Oxidant stress with hydrogen peroxide attenuates calcium paradox injury: role of protein kinase C and ATP-sensitive potassium channel

Available literature on the use of pharmacologic agents for the treatment of sleep-disordered breathing was reviewed by evidenced-based methodology. Evidence tables were created and studies were graded according to study design and the number of subjects included. Scores for each group of studies evaluating each pharmacologic agent were established so that the quality of research for different drugs could be compared. The use of various ventilatory stimulants, psychotropic drugs, and antihypertensive agents were reviewed. The most objective data are available on theophylline and opioid antagonist/nicotine groups. Although more controlled studies would be helpful, relatively clear-cut indications for the use of ventilatory stimulants exist for hypercapnic obesity-hypoventilation patients (medroxyprogesterone), myxedema (thyroid replacement), central apnea (acetazolamide), and periodic breathing in congestive heart failure (theophylline). Few randomized, well-controlled trials have been published that evaluate pharmacologic agents in the treatment of classic OSA. To date, no one agent stands out as being useful for OSA. Future research will need to characterize subjects so that various subsets of patients can be tried on one or on a combination of various pharmacologic agents.     

MR gradient echo volumetric analysis of human cardiac casts: focus on the right ventricle

BACKGROUND/PURPOSE: The antenatal diagnosis of sacrococcygeal teratoma (SCT) is increasingly being made with fetal sonography. However, the natural history of SCT detected on routine obstetric sonogram is not well defined. METHODS: A retrospective chart review of 21 fetal SCT diagnosed on routine sonography at Hospital Sainte-Justine between 1980 and 1997 were performed. The patients' clinical and sonographic characteristics, prenatal, and perinatal outcomes were examined. Prognostic criteria were identified by correlating patients' characteristics with outcome. RESULTS: In utero mortality rate was 19% and perinatal mortality rate was 14%. The incidence of premature labor was 50%. Of the various criteria examined as an independent variable, the presence of a solid tumor was found to be a important negative prognostic factor with a 67% incidence of death in utero and an overall mortality rate of 100%. Patients with new onset polyhydramnios were at significant risks for premature labor (100%). All of the perinatal deaths were attributable to tumor rupture. CONCLUSIONS: The course of sacrococcygeal teratoma diagnosed on routine sonograms is associated with a higher-than-expected incidence of prenatal and perinatal complications. Close antenatal follow-up for new onset polyhydramnios and the presence of a completely solid tumor will help optimize patient counseling and treatment.     

Grain refinement of magnesium alloys

The literature on grain refinement of magnesium alloys is reviewed with regard to two broad groups of alloys: alloys that contain aluminum and alloys that do not contain aluminum. The alloys that are free of aluminum are generally very well refined by Zr master alloys. On the other hand, the understanding of grain refinement in aluminum bearing alloys is poor and in many cases confusing probably due to the interaction between impurity elements and aluminum in affecting the potency of nucleant particles. A grain refinement model that was developed for aluminum alloys is presented, which takes into account both alloy chemistry and nucleant particle potency. This model is applied to experimental data for a range of magnesium alloys. It is shown that by using this analytical approach, new information on the refinement of magnesium alloys is obtained as well as providing a method of characterizing the effectiveness of new refiners. The new information revealed by the model has identified new directions for further research. Future research needs to focus on gaining a better understanding of the detailed mechanisms by which refinement occurs and gathering data to improve our ability to predict grain refinement for particular combinations of alloy and impurity chemistry and nucleant particles. This article is based on a presentation made in the symposium entitled “Phase Transformations and Deformation in Magnesium Alloys,” which occurred during the Spring TMS meeting, March 14–17, 2004, in Charlotte, NC, under the auspices of ASM-MSCTS Phase Transformations Committee.     

Transbronchial biopsy and bronchiolitis obliterans organizing pneumonia

The aim of the present study was to investigate the role of maternal smoking during pregnancy in the occurrence of the premature rupture of the membranes (PROM) and premature labor . Our study consisted of 1,133 women of which 283 (group A) had premature labor (gestation < or = 37 weeks), while 850 (group B) had term labor (gestation > 37 weeks). The two groups did not differ in their socioeconomic status and did not include women with serious complications during pregnancy. There were no apparent effects of smoking on the length of gestation. However, our results showed that smoking had a marked effect on preterm labor of less than 32 weeks; we also found a statistically significant correlation between PROM in premature deliveries and smoking during pregnancy, but no gradient was observed between the number of cigarettes smoked per day and the risk for PROM, in cases of premature labor. We conclude that smoking during pregnancy raises the risk of delivery before the 32nd week, as well as the PROM in premature deliveries, independently of the number of cigarettes smoked per day.     

Septo-optic dysplasia associated with bilateral complex microphthalmos

Examination of magnesium concentrations in the blood serum was carried out on a population of 246 patients 17-39 years old in pathologic/imminent abortion, imminent immature and premature labour and normal pregnancies as well as in first periods of parturition. In spite of considerable oscillations of magnesium concentrations in respective periods of normal and imminent pregnancies, the differences were statistically insignificant. A significant decrease of magnesium concentrations was found in the first period of parturition as compared with the imminent and normal pregnancies of the first and second trimester.     

Ability of naloxone to enhance the colonoscopic appearance of normal colon vasculature and colon vascular ectasias

OBJECTIVE: To compare the safety and efficacy of high-dose intravenous (IV) nitroglycerin with those of IV magnesium sulfate for acute tocolysis of preterm labor. METHODS: Thirty-one women with preterm labor before 35 weeks' gestation were assigned randomly to IV magnesium sulfate or IV nitroglycerin for tocolysis. Preterm labor was defined as the occurrence of at least two contractions in 10 minutes, with cervical change or ruptured membranes. Acute tocolysis was defined as tocolysis for up to 48 hours. Magnesium sulfate was administered as a 4-g bolus, then at a rate of 2-4 g/h. Nitroglycerin was administered as a 100-microg bolus, then at a rate of 1- to 10-microg/kg/min. The primary outcome measure was achievement of at least 12 hours of successful tocolysis. RESULTS: Thirty patients were available for analysis. There were no significant differences in gestational age, cervical dilation, or incidence of ruptured membranes between groups at the initiation of tocolysis. Successful tocolysis was achieved in six of 16 patients receiving nitroglycerin, compared with 11 of 14 receiving magnesium sulfate (37.5 versus 78.6%, P = .033). Tocolytic failures (nitroglycerin versus magnesium sulfate) were due to persistent contractions with cervical change or rupture of previously intact membranes (five of 16 versus two of 14), persistent hypotension (four of 16 versus none of 14), and other severe side effects (one of 16 versus one of 14). Maternal hemodynamic alterations were more pronounced in patients who received nitroglycerin, and 25% of patients assigned to nitroglycerin treatment had hypotension requiring discontinuation of therapy. CONCLUSION: Tocolytic failures were more common with nitroglycerin than with magnesium sulfate. The hemodynamic alterations noted in patients receiving nitroglycerin, including a 25% incidence of persistent hypotension, might limit the usefulness of IV nitroglycerin for the acute tocolysis of preterm labor.     

镁合金熔炼过程中的阻燃保护方法及进展

综述了镁合金熔炼过程中的熔剂保护、气体保护及合金化阻燃保护的研究现状及进展。熔剂保护和气体保护是目前国内外应用最为广泛的镁合金阻燃方法,但同时带来了环境污染等问题。研制经济、实用、无污染的镁合金熔炼保护方法将有利扩大镁合金的生产。