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The polyketide antibiotic Frenolicin-B (FB) produces anorexia and esophageal epithelial hyperplasia (EH) in rats, findings that are characteristic of zinc deficiency. Because FB also chelates divalent cations in vitro, we conducted studies to determine whether FB modifies blood and organ concentrations of zinc and other essential metals (calcium, copper, iron and magnesium). Groups of male Sprague-Dawley rats (~250g; n = 20/group) consumed diets with adequate (40 [micro]g/g), deficient ( KEY WORDS: * copper * Frenolicin-B * antibiotics * rats

The loss of adipose tissue during energy restriction may be accompanied by a loss of lean body mass, including bone mass. Because most of the body lead burden is in the skeleton, we studied the effects of weight loss on the concentrations of lead in bone, blood and several organs in rats with prior but not current lead exposure. Concentrations of the essential divalent metals calcium, copper, iron, magnesium and zinc were also determined for comparison with lead. Lead-exposed rats (n = 25) were randomly assigned to one of three treatment groups: weight maintenance (WM), moderate weight loss (MWL) or substantial weight loss (SWL). For the two last-named groups, food intake was restricted for 4 wk to 70 and 40% of that of the WM group. Lead concentrations did not differ significantly (ANOVA, P > 0.05) among the three groups for blood, brain and bone. Significantly higher liver lead concentrations were observed in the SWL rats than in the WM and MWL groups. In general, organ concentrations of calcium, copper, magnesium and zinc were either lower or did not differ in the groups losing weight compared with the WM group. in contrast, organ iron concentrations of the SWL group were higher than those of the other groups except in brain where there were no significant differences. The total liver content of lead was highest in the SWL group, but the lead content of other organs did not differ among the treatment groups. The contents of calcium, copper, magnesium and zinc generally were lower in the MWL and SWL groups than in the WM group in the liver and some of the other organs. The results demonstrate that weight loss can increase the quantity and concentration of lead in the liver, even in the absence of continued lead exposure. The data also demonstrate considerable differences among organ divalent metals in response to weight loss. INDEXING KEY WORDS: lead; weight loss; essential metals; liver; rats

A low dose multivitamin and mineral supplement can substantially improve the delayed hypersensitivity skin test responses of elderly people over a 6- to 12-month period. This was gleaned from a study of the effects of a once-a-day type micronutrient supplement on immunity in people 59 years old and above. Significant increases were noted in the delayed hypersensitivity skin test responses of the subjects after 12 months.

We studied the effects of dietary calcium and lead exposure on lead toxicity, fatal and neonatal growth, erythropoiesis and blood pressure during pregnancy and lactation in rats. Pregnant Sprague-Dawley rats (n = 43) were randomly assigned to one of six treatment groups of 7-8 rats each. Half of the rats were fed diets of low (0.1%), normal (0.5%) or high (2.5%) calcium as calcium carbonate and exposed to 250 mg/L of lead in their drinking water for the duration of the pregnancy and for 1 wk of lactation. Three control groups were fed the same diets without lead exposure. Pups were studied at 1 d and 1 wk of age. Maternal and fatal blood and organ samples from the groups fed the low calcium diet had the highest lead concentrations, whereas the lowest lead concentrations were found in the groups fed the high calcium diet. Dam and pup hemoglobin concentrations, hematocrits, and body weights and lengths were reduced by lead exposure and by the high calcium diet. The latter also reduced organ iron concentrations and prevented lead-induced increases in free erythrocyte protoporphyrin. Dam systolic blood pressures during the third trimester of gestation were significantly higher in rats exposed to lead and fed the low calcium diet than in rats in the other five treatment groups. The results demonstrate that dietary calcium and lead exposure interact in rats to influence maternal blood pressure, erythropoiesis, and fatal and neonatal growth during pregnancy and lactation. INDEXING KEY WORDS: pregnancy; calcium; lead; blood pressure; rats

A study was done to determine the effects of different concentrations of dietary calcium on organ lead accumulation in rats chronically exposed to lead for long periods of time. Results show a decrease in organ lead concentrations with increasing dietary calcium. Lead was also shown to inhibit the increase of renal calbindin levels in animals fed with two and a half percent of calcium.

Abstract Background Although there is considerable evidence for a loss of bone mass with weight loss, the few human studies on the relationship between weight cycling and bone mass or density have differing results. Further, very few studies assessed the role of dietary composition on bone mass during weight cycling. The primary objective of this study was to determine if a diet high in amylase-resistant starch (RS2), which has been shown to increase absorption and balance of dietary minerals, can prevent or reduce loss of bone mass during weight cycling. Methods Female Sprague-Dawley (SD) rats (n = 84, age = 20 weeks) were randomly assigned to one of 6 treatment groups with 14 rats per group using a 2 × 3 experimental design with 2 diets and 3 weight cycling protocols. Rats were fed calcium-deficient diets without RS2 (controls) or diets high in RS2 (18% by weight) throughout the 21-week study. The weight cycling protocols were weight maintenance/gain with no weight cycling, 1 round of weight cycling, or 2 rounds of weight cycling. After the rats were euthanized bone mineral density (BMD) and bone mineral content (BMC) of femur were measured by dual energy X-ray absorptiometry, and concentrations of calcium, copper, iron, magnesium, manganese, and zinc in femur and lumbar vertebrae were determined by atomic absorption spectrophotometry. Results Rats undergoing weight cycling had lower femur BMC (p < 0.05) and marginally lower BMD (p = 0.09) than rats not undergoing weight cycling. In comparison to controls, rats fed RS2 had higher femur BMD (p < 0.01) and BMC (p < 0.05), as well as higher values for BMD and BMC measured at the distal end (p < 0.001 and p < 0.01) and femoral neck (p < 0.01 and p < 0.05). Consistent with these findings, RS2-fed rats also had higher femur calcium (p < 0.05) and magnesium (p < 0.0001) concentrations. They also had higher lumbar vertebrae calcium (p < 0.05) and magnesium (p < 0.05) concentrations. Conclusion Weight cycling reduces bone mass. A diet high in RS2 can minimize loss of bone mass during weight cycling and may increase bone mass in the absence of weight cycling.