Calcium homeostasis in pregnant women receiving long-term magnesium sulfate therapy for preterm labor.

OBJECTIVES: The hypothesis of this study is that calcium homeostasis and bone mineralization are altered in pregnant women receiving long-term therapy with magnesium sulfate as compared with similar women not receiving magnesium sulfate to control preterm labor. STUDY DESIGN: Thirty-nine women between 24 and 32 weeks' gestation, matched for age, race, and duration of bed rest, were enrolled. Indices of calcium homeostasis in serum and urine were measured serially, and bone mineralization of the distal radius was measured at 1 and 11 weeks post partum. RESULTS: Magnesium therapy was administered for a mean duration of 26 +/- 14 days and a cumulative dose of 1405 +/- 963 gm. Serum concentrations of magnesium, phosphorus, and parathyroid hormone increased and those of calcium decreased from baseline values in the magnesium sulfate group and remained uniform throughout the 3-week investigation. The serum magnesium, phosphorus, parathyroid hormone, and calcium concentrations in the control group were unchanged during the study and differed significantly from those in the magnesium sulfate group (p < 0.001). Urinary output of magnesium, calcium, and copper was significantly greater in the magnesium sulfate group than in the control group throughout the study. Urinary losses of calcium in the magnesium sulfate group, approximately 800 to 900 mg/day, were substantial. Although radius bone density 1 week post partum did not differ between groups, the change in bone density from 1 to 11 weeks post partum was significantly lower in the magnesium sulfate group than in controls. CONCLUSIONS: These data suggest that calcium homeostasis is altered during and after long-term magnesium sulfate therapy. The marked, prolonged urinary calcium losses may affect maternal bone mineralization.     

Anaphylactoid reactions associated with reuse of hollow-fiber hemodialyzers and ACE inhibitors.

From July 18 through November 27, 1989, 12 anaphylactoid reactions (ARs) occurred in 10 patients at a hemodialysis center in Virginia. One patient required hospitalization; no patients died. ARs occurred within minutes of initiating dialysis and were characterized by peripheral numbness and tingling, laryngeal edema or angioedema, facial or generalized sensation of warmth, and/or nausea or vomiting. All 12 ARs occurred with dialyzers that had been reprocessed with an automated reprocessing system. A cohort study, including all patients undergoing dialysis sessions on the six days when an AR occurred, showed that the patients who experienced ARs were significantly more likely than patients who did not to be treated with angiotensin-converting enzyme (ACE) inhibitors (7/10 vs. 3/33; relative risk = 7.9; 95% confidence interval = 2.5 to 25.2) and to have been exposed to reused dialyzers rather than to new dialyzers (12/70 sessions vs. 0/31; P = 0.016). In those sessions using a reused dialyzer, the mean number of dialyzer uses in case-sessions was significantly higher than for noncase-sessions (10.3 vs. 6.2; P = 0.016). After reuse of dialyzers was discontinued at the center, no further ARs occurred, despite the continued administration of ACE inhibitors. This is the first report of an outbreak of ARs associated exclusively with reused dialyzers. We hypothesize that interactions between a dialyzer that has been repeatedly reprocessed and reused, blood, and additional factors, such as ACE inhibitors, increased the risk of developing ARs.     

Psychosocial Factors and Prediction of Headaches in College Adults

The current study evaluated psychosocial variables that may contribute to the experience of headache in college adults. One hundred ninety-nine participants, 103 women and 96 men, completed head pain logs for 4 weeks after completing measures assessing psychosocial variables. Multiple regression analyses indicated that level of emotional functioning, perception of stress, and gender were predictive of future headache frequency, intensity, and duration. Family history and health habits did not predict headache activity. These findings are consistent with research investigating psychosocial variables and headache activity.     

Ethanol Feeding Causes Inactivation of Both State 1 and State 2 Rat Hepatic Asialoglycoprotein Receptors

Previous studies have shown that ethanol feeding in rats causes inactivation and redistribution of ˜50% of the total asialoglycoprotein receptors (ASGPRs) in hepatocytes (Tworek et al., J. Biol. Chem. 271:2531, 1996), and that two equal populations of hepatic ASGPRs mediate ligand uptake and processing via two functionally different pathways (Weigel in Glycoconjugates: Composition, Structure and Function , Marcel Dekker, 1992, p. 421). The purpose of this study was to determine if ethanol feeding causes preferential inactivation of only one of these two ASGPR populations, which have been designated state 1 and state 2 ASGPRs. The state 2, but not state 1, ASGPRs are inactivated in isolated hepatocytes by a variety of drugs and inhibitors. State 2 ASGPRs can also be inactivated in permeable cells by ATP treatment and then reactivated by treatment with fatty acyl coenzyme As. In the present study, permeable cell assays for state 2 ASGPR inactivation and reactivation were used to assess whether hepatocytes from ethanol-fed rats contain inactive state 2 ASGPRs. The results show that preferential inactivation of one ASGPR population does not occur after ethanol feeding. That inactive ASGPRs could not be reactivated by treatment with palmitoyl-coenzyme A to a greater extent in ethanol-fed versus control cells indicates there is not a larger pool of inactivated state 2 ASGPRs in treated cells. We conclude that ethanol feeding causes equal inactivation of both state 1 and state 2 ASGPRs. Ethanol feeding may represent the first treatment found to inactivate state 1 ASGPRs.     

Psychiatric disorders in pediatric primary care. Prevalence and risk factors

Children aged 7 to 11 years visiting their primary care pediatrician for a wide range of reasons were studied to determine the one-year prevalence of DSM-III disorders and the risk factors associated with them. Parents completing the Child Behavior Checklist about their children identified problems that placed 24.7% of 789 children in the clinical range. Detailed psychiatric interviews with 300 parents and children, using the Diagnostic Interview Schedule for Children, yielded a one-year weighted prevalence of one or more DSM-III disorders of 22.0% +/- 3.4%, combining diagnoses based on either the child or the parent interview.     

Effects of inotropes on human leucocyte numbers, neutrophil function and lymphocyte subtypes

We have investigated the effects of inotropes with different adrenergic receptor specificity on differential white cell count, lymphocyte subtypes and neutrophil function in healthy volunteers. Six healthy, male volunteers were enrolled into this randomized, placebo-controlled pilot study. Each volunteer was studied on four separate occasions during a 2-h infusion of various agents, and for 2 h after stopping the infusion. The agents investigated were adrenaline 0.1 microgram kg-1 min-1, dobutamine 5 micrograms kg-1 min-1, dopexamine 2 micrograms kg-1 min-1 and 5% glucose 0.5 ml kg-1 h-1. Venous blood was sampled at 0, 30, 120 and 240 min. Haemodynamic monitoring was continued throughout the study. Full blood count, white cell differential count and enumeration of lymphocyte subtypes were performed. Neutrophil function tests included chemoluminescence, and assessment of neutrophil chemotaxis, phagocytosis and adhesion. The Wilcoxon signed rank test was used to compare differences between placebo and active drugs at each time compared with baseline. There was a significant increase in white cell count, lymphocyte count and neutrophil count with adrenaline, and a small but significant decrease in these variables with dobutamine and dopexamine. These changes were also apparent for absolute CD3+, CD4+ and CD8+ lymphocyte counts. Neutrophil respiratory burst in response to f-methionyl-leucyl-phenylalanine increased significantly only with adrenaline at 30 min (P = 0.046). There were no other significant changes in tests of neutrophil function. Infusion of inotropes was associated with changes in white cell numbers, lymphocyte subtypes and neutrophil respiratory burst. In healthy volunteers, adrenaline had effects different from those of dobutamine and dopexamine. The clinical relevance of such effects requires further investigation in critically ill patients.      

Effect of varying fibrinogen and hematocrit concentrations on magnetic resonance relaxation times of thrombus.

OBJECTIVES. The authors assessed the effects of varying one extracellular component (fibrinogen concentration) and one cellular component (hematocrit) on magnetic resonance (MR) T1 and T2 relaxation times of in vitro blood clots. METHODS. Blood from six male subjects was collected into sodium citrate anticoagulant (3.8%) and the whole blood was separated into platelet-rich plasma and packed erythrocytes. Subsequently, in vitro blood clots were made from varying concentrations of fibrinogen (1, 10, and 100 microM) in Tyrode's solution and washed, packed erythrocytes (hematocrit levels: 0%, 10%, 40%, and 80%). T1 and T2 measurements were completed at 20 MHz within 8 hours of initiating clotting. RESULTS. Significant shortening of MR relaxation times occurred with increasing fibrinogen concentration for hematocrit values of 0% and 10%. Extracellular fibrinogen concentration did not contribute significantly to variation in relaxation times at hematocrit values of 40% and 80%. For any given fibrinogen level, significant shortening occurred in T1 and T2 values for each successive increase in hematocrit values. CONCLUSIONS. Both extracellular (fibrinogen) and cellular (erythrocyte concentration) factors are significant determinants of thrombus T1 and T2 relaxation times.     

Executive cognitive deficits in primary dystonia.

Primary dystonia is a disorder of movement for which no consistent pathophysiology has been identified; in the absence of evidence to the contrary, it is assumed to be cognitively benign. We have studied a clinically heterogeneous group of 14 patients with primary dystonia on a battery of neuropsychological tests. Despite well-preserved speed of information processing, language, spatial, memory and general intellectual skills relative to normal controls, we have identified a constellation of attentional-executive cognitive deficits on the Cambridge Neuropsychological Test Automated Battery (CANTAB). Specifically, patients demonstrated significant difficulties negotiating the extra-dimensional set-shifting phase of the IED task. The implications of these findings for the pathophysiology of primary dystonia are discussed. This is, to the best of our knowledge, the first report of a significant cognitive deficit in patients with primary dystonia.