Jeanette M. Hosseini

Magnesium measures across the menstrual cycle in premenstrual syndrome.

The purpose of this study was to evaluate blood magnesium (Mg) measures across the menstrual cycle in women with premenstrual syndrome (PMS) and control women. Longitudinal determinations of plasma, red blood cell (RBC) and mononuclear blood cell (MBC) Mg were made in 26 women with prospectively confirmed PMS and in a control group of 19 women. Data were analyzed using analysis of variance with repeated measures and Spearman rank correlations. Significant diagnostic group effects were observed for RBC and MBC Mg concentrations (p < 0.05). These effects reflected lower Mg concentrations in PMS patients at each sampling time. No significant effects were observed for either plasma Mg or MBC Mg content, nor were there significant time by diagnosis effects for any of the measures. Consistent with earlier studies, we found decreased RBC Mg concentrations and additionally observed decreased MBC Mg concentrations in women with PMS. However, neither of these relative deficits were confined to the luteal phase.

Effect of dextroamphetamine and methylphenidate on calcium and magnesium concentration in hyperactive boys

Levels of calcium in plasma, red blood cells, and mononuclear blood cells, levels of calcium in plasma, and the plasma calcium-to-magnesium ratio were measured at baseline and after 3 weeks of each drug phase of a double-blind, placebo-controlled study of methylphenidate and dextroamphetamine in hyperactive boys. Levels of magnesium in plasma were significantly higher after 3 weeks of dextroamphetamine treatment, and the calcium-to-magnesium ratio was significantly lower after 3 weeks of either drug compared with the baseline or placebo condition. There was no change in magnesium levels in red blood cells or mononuclear blood cells. These measures were obtained 30 minutes before the morning dose and at 9 a.m., 9:30 a.m., 10:30 a.m., 11:00 a.m., and noon on the last day of each 3-week phase. Analysis of variance revealed a drug effect on plasma magnesium and on the calcium-to-magnesium ratio but no drug x time interaction. Although these changes were not correlated with the time course of acute symptomatic response to stimulant therapy, the decrease in the ratio may be relevant to side effects and treatment resistance associated with stimulant use.

Endotoxemia in sudden infant death syndrome.

Endotoxemia has been proposed as a significant cause of Sudden Infant Death Syndrome (SIDS). We examined postmortem sera from left and right heart samples of 21 SIDS cases (1989 definition) and 23 controls. The controls were <1 year of age and had died suddenly and unexpectedly of infection, abuse, suffocation, blunt injury, or fire and smoke inhalation. Endotoxin was measured without knowledge of the clinical status by using a kinetic modification of the chromogenic limulus amoe-bocyte lysate assay. The SIDS cases had insignificant concentrations of endotoxin in serum, whereas some of the controls who experienced blunt injury, abuse, or severe infection exhibited moderately elevated concentrations. Postmortem interval and postmortem blood culture results did not materially affect endotoxin concentrations. Thus, we conclude that endotoxemia is not a substantial pathophysiologic event in SIDS.

A sample preparation for quantitative determination of magnesium in individual lymphocytes by electron probe X‐ray microanalysis

We present a sample preparation method for measuring magnesium in individual whole lymphocytes by electron probe X‐ray microanalysis. We use Burkitts lymphoma cells in culture as the test sample and compare X‐ray microanalysis of individual cells with atomic absorption analysis of pooled cell populations. We determine the magnesium peak‐to‐local continuum X‐ray intensity ratio by electron probe X‐ray microanalysis and calculate a mean cell magnesium concentration of 39± 19 mmol/kg dry weight from analysis of 100 cells. We determine a mean cell magnesium concentration of 34 ±4 mmol/kg dry weight by atomic absorption analysis of pooled cells in three cell cultures. The mean cell magnesium concentrations determined by the two methods are not significantly different. We find a 10% coefficient of variation for both methods of analysis and a 30% coefficient of variation in magnesium concentration among individual cells by electron probe X‐ray microanalysis. We wash cells in ammonium nitrate for microanalysis or in buffered saline glucose for atomic absorption analysis. We find cells washed in either solution have the same cell viability (85%), recovery (75%), cell volume (555 μm3) and cytology. We air dry cells on thin film supports and show by magnesium X‐ray mapping that magnesium is within the cells. We conclude that: (a) our microanalysis cell preparation method preserves whole intact lymphocytes; (b) there is no systematic difference in results from the two methods of analysis; (c) electron probe X‐ray microanalysis can determine the variation in magnesium concentration among individual cells.