PubMed Health⌕ Search

Biomedical subjects

R G Haas

Publications and source records attributed to R G Haas.

8 recordsLinked to original sources
PubMed1992

Can the magnesium content of mononuclear blood cells be altered by oral magnesium supplementation?

A randomized, double-blind, placebo-controlled trial was performed on a rigorously defined group of normal subjects to see if magnesium (Mg) supplementation could affect serum Mg levels or Mg content of mononuclear blood cells. Forty-nine subjects were randomized to either placebo, tablets containing 90% United States recommended daily allowance (USRDA) of Mg, or tablets containing 180% USRDA of Mg. We were unable to demonstrate a statistically significant increase in Mg content of mononuclear blood cells.

Adult↗
PubMed1992

Relation between magnesium and potassium concentrations in myocardium, skeletal muscle, and mononuclear blood cells.

Potassium and magnesium were measured in 26 cardiac surgery patients (right atrial appendage), 23 autopsy subjects (right atrial appendage, left ventricular free wall, and skeletal muscle), and 9 healthy volunteers (mononuclear blood cells) to determine whether there was a relation between these two ions in the tissues measured. In the cardiac surgery patients, the potassium and magnesium concentrations were 46.35 +/- 3.89 and 4.40 +/- 0.58 (mean +/- SD, mumol/g wet weight tissue), respectively, and were significantly correlated (r = 0.54, P = 0.005). In the autopsy group, the respective concentrations were: for right atrial appendage, 30.54 +/- 10.18 and 3.66 +/- 0.70 mumol/g (r = 0.38, P = 0.14); left ventricular free wall, 60.69 +/- 17.93 and 7.74 +/- 1.73 mumol/g (r = 0.92, P = 0.0001); and skeletal muscle, 93.05 +/- 20.49 and 8.64 +/- 2.06 mumol/g (r = 0.91, P = 0.0001). In the healthy volunteer group, the results for potassium and magnesium in mononuclear blood cells were 42 +/- 9.9 and 3.99 +/- 0.70 fmol/cell, respectively (r = 0.94, P = 0.0001). Thus, potassium and magnesium concentrations were significantly correlated in all the tissues measured.

Aged↗
PubMed1991

Myocardial magnesium: relation to laboratory and clinical variables in patients undergoing cardiac surgery.

Magnesium concentration was measured in the right atrial appendage of 100 patients undergoing cardiac surgery and associations with serum and mononuclear blood cell magnesium, other laboratory values and patient clinical variables were studied. In addition, magnesium was measured in the right atrial appendage and left ventricular free wall in 23 autopsy subjects to determine whether there was a proportional relation between right atrial appendage and left ventricular free wall magnesium. The mean left ventricular free wall/right atrial appendage magnesium ratio was 2.13 +/- 0.39 (r = 0.67, p = 0.0009). In the group with cardiac surgery, the right atrial appendage magnesium concentration correlated inversely with age (r = -0.54, p = 0.001). The mean right atrial appendage magnesium concentration (micrograms/g wet weight tissue) was lower in patients with postoperative cardiac arrhythmia than in those without arrhythmia (103 +/- 13 versus 111 +/- 10, p = 0.009) and in diabetic than in nondiabetic patients (103 +/- 13 versus 109 +/- 12, p = 0.02). The right atrial appendage magnesium concentration also tended to be lower in patients receiving potassium/magnesium-losing diuretics, although this difference did not achieve statistical significance (105 +/- 14 versus 109 +/- 11, p = 0.16). Right atrial appendage magnesium concentration correlated positively with serum creatinine concentration (r = 0.31, p = 0.002) and negatively with serum calcium concentration (r = -0.29, p = 0.013). Serum magnesium did not correlate with right atrial appendage or mononuclear blood cell magnesium concentration or clinical variables. There was a statistically significant correlation between mononuclear blood cell and right atrial appendage magnesium concentrations in some subgroups of patients.

Aged↗
PubMed1989

Causes of iron deficiency in adolescent athletes.

Seventy-two high school cross-country runners were studied during the running session for possible etiologic factors associated with iron deficiency, which was defined as a serum ferritin level less than or equal to 12 ng/ml and a transferrin saturation of less than or equal to 16% occurring simultaneously. Iron deficiency was observed during the running season in 34% of female cross-country runners, compared with 8% of male runners. Increased iron losses through gastrointestinal bleeding occurred in 9 of 20 female runners; 7 of these 9 had iron deficiency. Dietary iron intake was low in both iron-deficient and iron-sufficient female runners, but dietary instruction did not increase iron intake significantly. Iron deficiency could not be prevented in 35% of the female runners treated with 60 mg of elemental iron daily, but adequate treatment was achieved with 180 mg. Iron losses in urine, sweat, and plasma were small and did not appear to be increased in iron-deficient runners. These findings indicate that female cross-country runners have a high incidence of iron deficiency that is associated with initially decreased iron stores and gastrointestinal bleeding.

Adolescent↗
PubMed1987

Intracellular magnesium of mononuclear cells from venous blood of clinically healthy subjects.

Measurement of intracellular magnesium (Mg2+) may have advantages over serum Mg2+ measurements in the assessment of Mg2+ homeostasis in patients. An accurate and reproducible method of measuring the Mg2+ content of mononuclear cells (lymphocytes and monocytes) from the venous blood of human subjects utilizing commonly available reagents and equipment is described. A well-defined clinical population of 88 subjects (48 males and 40 females) was used as the normal population. The mean mononuclear cell Mg2+ content was 67.8 +/- 13.8 (SD) fg/cell giving a 95% confidence interval normal range of 40-95 fg/cell which compared favorably to the empirical 95% limits of 44-94 fg/cell. The serum Mg2+ measured at the same time was 0.90 +/- 0.06 (SD) mmol/l. No significant correlation was found when comparing serum and mononuclear cell Mg2+ concentrations. Additionally, no significant differences were found when serum and intracellular Mg2+ were analyzed for sex and age with the exception that intracellular Mg2+ tended to be slightly higher in the younger age groups. The routine performance of this assay may require as little as 7 ml of venous blood and was done with a coefficient of variation of 3.0-3.6%.

Adult↗
PubMed1982

Modified Dupont aca calcium method for hemolyzed specimens.

The presence of hemoglobin in serum or plasma causes an increase in the apparent calcium concentration when this determination is performed on the DuPont Automatic Clinical Analyzer (aca). A simple pack modification is described using ethylene glycol-bis-(2-aminoethylether)-tetracetic acid (EGTA) which permits estimation of the positive interference due to hemoglobin color. A correction factor is applied to enable the accurate measurement of calcium in hemolyzed samples.

Blood Chemical Analysis↗