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Biomedical subjects

K B Franz

Publications and source records attributed to K B Franz.

12 recordsLinked to original sources
PubMed2006

Influence of graded magnesium deficiencies on white blood cell counts and lymphocyte subpopulations in rats.

Increased white blood cell counts or leukocytosis have been observed primarily in young rats fed diets extremely low in Mg (< 60 ppm) and high in phosphorus (0.5 % P). We investigated the influence that acute and moderate Mg deficiencies have on blood leukocytes at high and low dietary phosphorus levels. For four weeks, male Sprague-Dawley rats (initially 7 weeks old) were fed diets containing 30, 60, 120, 208, or 850 ppm Mg and either 0.3 % or 0.5 % dietary phosphorus. Total leukocytes were increased in rats fed 30 ppm Mg (p < 0.0001), and the leukocyte subpopulation counts of lymphocytes, neutrophils, monocytes and eosinophils increased significantly only in the rats fed 30 ppm Mg (p < 0.0001). B-cells decreased significantly as a percentage of lymphocytes (p < 0.0093) as dietary Mg decreased. As total counts in blood, B-cells, CD4 and CD8 cells were significantly increased in the rats consuming the 30 ppm Mg diet. Dietary phosphorus only had an effect in combination with the lowest dietary Mg. These results demonstrate a threshold effect for increased leukocytes during a Mg deficiency of four weeks. A Mg deficiency of a longer duration may show different results.

Animals↗
PubMed2006

Dietary magnesium deficiency decreases plasma melatonin in rats.

It has been postulated that Mg depletion is associated with decreased melatonin. Exogenous magnesium (Mg) has been found to increase the activity of serotonin N-acetyltransferase, an enzyme in the pathway for melatonin synthesis; but no data have been found on the effect of Mg deficiency on plasma melatonin. This pilot study examined the effect of a dietary Mg deficiency on plasma melatonin in male, Sprague-Dawley rats. Weanling rats were placed on a Mg-deficient (150 ppm) or a Mg-adequate (1000 ppm) diets for four weeks, after which they were sacrificed 4, 5 or 7 hours into the dark cycle. Plasma was assayed for melatonin concentrations. A significant decrease (p = 0.0101) occurred in mean (+/- SEM) plasma melatonin levels of the Mg-deficient animals (50 +/- 6.4 pg/mL) when compared to the Mg-adequate animals (75 +/- 6.6 pg/mL). There was no obvious phase shift in the melatonin profile of the Mg-deficient animals when compared to the Mg-adequate animals.

Animals↗
PubMed1990

A synergism of antigen challenge and severe magnesium deficiency on blood and urinary histamine levels in rats.

The effects of severe and moderate magnesium (Mg) deficiency on blood and urinary histamine were studied in 36 male weanling Sprague-Dawley rats with or without IgE-stimulating antigen challenge. The rats were divided into six groups: two each on 50 (severely deficient), 300 (moderately deficient), and 2000 (control) ppm Mg diets without and with immunization with ovalbumin challenge on days 0, 14, and 29. Unimmunized severely Mg-deficient rats had significantly elevated urinary histamine which returned to normal by 22 days, but whole blood histamine was still significantly elevated at 36 days. Both blood and urinary histamine of immunized severely Mg-deficient rats were significantly higher than those of all the other groups throughout the study, particularly after the antigen challenge. There was a synergism of antigen challenge and severe Mg deficiency on blood and urinary histamine levels. The results suggest that severe Mg deficiency can aggravate diseases which are caused by abnormal histamine release after exposure to an IgE-stimulating antigen.

Animals↗
PubMed1989

Influence of dietary magnesium on the amplitude of wave V of the auditory brainstem response.

Thirty-six weanling guinea pigs were fed either a low (600 ppm) or normal (3000 ppm) diet of magnesium for 8 weeks. One half of each diet group received intramuscular injections of magnesium-depleting drugs, furosemide and gentamicin. The other half were controls and received equal intramuscular injections of saline. Auditory brainstem responses were obtained from all animals before and after 8 weeks of treatment of diet and drugs to examine the effects of treatment upon hearing and auditory brainstem function. A three-way analysis of variance of dietary magnesium, by drug and by sex, showed no significant differences in auditory brainstem wave V thresholds, wave V latencies, or interpeak wave I-V latencies between the control and experimental groups. The low magnesium diet group, which received drugs, had significantly greater wave V auditory brainstem response amplitudes. Results can be explained on the basis of magnesium influencing the uptake of calcium into both the hair cells and associated brainstem pathways.

Animals↗
PubMed1987

Magnesium intake during pregnancy.

The mean dietary magnesium intake of pregnant women is 35-58% of the recommended dietary allowance of 450 mg. Low-income women consumed 97-100 mg magnesium/1,000 kcal while women with higher incomes averaged 120 mg/1,000 kcal. Diets high in fat and sugar and low in whole grains, vegetables and fruits have a lower magnesium density. Magnesium content of water can also make a significant contribution to magnesium intake. Magnesium from prenatal supplements, if present, is seldom more than 100 mg. Additional supplementation is needed for adequate magnesium nutriture during pregnancy.

Calcium↗
PubMed1985

Physiologic changes during a marathon, with special reference to magnesium.

In a single case study of a moderately trained, healthy man, physiologic changes during a marathon are reported. Blood was drawn prior to the race, at 1 hour and 2 hours into the race, at the end of the race, and after 1 hour of recovery. By 1 hour into the race, norepinephrine, epinephrine, and dopamine had increased nearly nine-fold, two-fold and five-fold, respectively. After 1 hour of recovery, epinephrine had returned to the pre-race value but norepinephrine and dopamine were still elevated. Cortisol increased gradually and was more than doubled by the end of the race. It was still elevated after 1 hour of recovery. White blood cells gradually increased, reaching their maximum value at the end of the race; a four-to-five-fold increase. Thromboxane B2, which had an inverse relationship to serum magnesium, was below the pre-race value for the first 2 hours but increased nine-fold by the end of the race. Serum magnesium increased from 1.44 meq/l to 1.68 meq/l at 2 hours into the marathon, dropped to 1.07 meq/l by the end of the race, and returned to its pre-race value by 1 hour of recovery. The decrease in serum magnesium at the end of the race may be associated with increased plasma free fatty acid levels.

Adult↗
PubMed1980

Relative bioavailability of zinc using weight gain of rats.

Weanling rats were fed semi-purified diets with varying zinc levels in order to derive new measures of relative bioavailability of zinc (RBAZ). The various measures for RBAZ were slope-ratio assays of weight gain, total liver zinc and total femur zinc along with five alternative measures developed from sigmoidal curves for weight gain estimated by a non-linear, least-squares curve fitting computer program. The slopes of weight gains explained a higher proportion of the true measure than similar slopes of femurs or livers as indicated by R2. The 95% confidence intervals of ratios were narrowest for weight gain assays. Four of the five alternative methods had RBAZ similar to the RBAZ of slope-ratio weight gain assays. These new methods provided a diversity of information and allowed more information to be obtained than from slope-ratio assays alone.

Animals↗
PubMed1980

Relative bioavailability of zinc from selected cereals and legumes using rat growth.

The relative bioavailability of zinc (RBAZ) in corn, rice, wheat and legumes was determined by the ratio of net weight gains a 6 ppm of added zinc, a measure derived from sigmoidal curves for weight gain estimated by a non-linear, least-squares curve fitting computer program. Each food was prepared as for human consumption, incorporated into a semi-purified diet to provide varying levels of zinc and fed to weanling rats. Among cereals, whole corn and brown rice had low RBAZ (0.58 or less), while whole wheat flour and unleavened whole wheat bread had medium values (0.63-0.74). Refined cereal grains, such as white flour, leavened and unleavened white bread and white rice, had high RBAZ (0.89-1.08) as did leavened whole wheat bread (1.04). Of the legumes, lima beans had a high RBAZ (0.84) while white beans had a medium value (0.74). Phytic acid content of the foods, but not neutral-detergent fiber content, appeared to be inversely related to RBAZ, more so among the cereals than with the legumes.

Animals↗