Immunopathology of chronic cadmium administration in mice.

Young male mice were given drinking water containing 50 ppm cadmium (Cd) for 3 weeks, and were killed 0, 3 and 6 weeks after the cessation of treatment. At 0 weeks, suppression in the number of splenic plaque-forming cells in response to sheep red blood cell immunization was noted 5 days after antigen injection, but not 7 days after injection. Plasma IgG concentration and thymic factor activity were unaffected at 0 weeks. The number of circulating lymphocytes tended to be less in the Cd-treated mice at all times. Cd treatment had no effect upon liver and kidney weights, and upon the weights and the lymphocyte contents of the thymus and spleen at any of the observation times. Employing immunofluorescence with anti-mouse IgG and C3, no evidence of an autoimmune response was found in the kidney of the treated mice at 0 and 3 weeks. Mitochondrial abnormalities in the renal proximal tubule cells were noted at 0 weeks in the Cd-treated mice. The Cd concentrations of the liver and kidneys remained high at all observation times. The results suggest that a modest dose of Cd produces some depression of the immune system, and the biological half-life of Cd is long.

Relationship of serum concentrations of several enzymes to the porcine stress syndrome.

Serum enzyme concentrations were determined in 319 Hampshire pigs (approx 2 months of age). Significant positive correlations were found when creatine kinase (CK) concentrations were compared with lactate dehydrogenase and malate dehydrogenase values, but not when compared with aspartate aminotransferase or alanine aminotransferase values. In an additional study, a litter from a sow with high serum CK concentrations was observed at 2, 3, 4, and 5 months of age for serum CK concentrations. The CK concentration increased as the pigs aged, and soft exudative pork was found upon slaughter of the pigs at 5 months of age. It is believed that CK, lactate dehydrogenase, and malate dehydrogenase determinations in weanling pigs would have value for reducing the frequency of the porcine stress syndrome and soft exudative pork in breeding stock. If only a portion of the genetic carriers was removed, the effect would be considerable within a few generations.

Dietary factors in essential hypertension.

Dietary alteration or intervention is an ideal method of preventing or treating hypertension. Medication may be eliminated or reduced in many cases. Correction of obesity and alcohol abuse are confirmed methods of treating hypertension. Reduction of sodium intake is effective in that portion of the population which is salt-sensitive. Probably, the ratio of sodium to potassium is of importance and increasing potassium intake while reducing sodium intake is effective in many situations. Evidence is being reported which indicates that adequate intake of calcium, and perhaps magnesium, is effective in preventing hypertension. Limited information indicates that a sufficiency of dietary essential fatty acids and fibre are effective in hypertension prevention. The role of dietary protein, carbohydrates, fat, cholesterol, vitamins, and essential elements (other than those mentioned above) in the pathogenesis has not been fully elucidated at this time, but there are indications that adequate intakes are beneficial in hypertension. Water hardness may have some effect in reducing hypertension incidence, and any effectiveness would probably result from calcium and magnesium in the drinking water. Animal studies and limited human studies indicate some detrimental effects of heavy metals, such as lead and cadmium, upon the pathogenesis of hypertension. Information regarding caffeine intake is inconclusive.

Relation of dietary carbohydrates to lipid metabolism and the status of zinc and chromium in rabbits.

Rabbits were fed a purified ration known to produce alterations in lipid metabolism and cholelithiasis. During a 14-week period, group 1 was fed sucrose as the sole dietary carbohydrate, whereas group 2 was fed corn starch; the rations were equicaloric and the carbohydrate provided 43% of the calories. Serum cholesterol and triglyceride concentrations increased when the purified rations were fed, and these concentrations were often greater (toward the end of the trial) in rabbits fed the sucrose than in rabbits fed corn starch. Liver weight was increased by the sucrose feeding, but there were no differences as to concentrations of lipid, cholesterol, Cr, or Zn between treatments. The aortas of the sucrose group contained more lipid, and the cholesterol concentrations tended to be greater; but dietary carbohydrate had no effect on concentrations of Cr or Zn. A reduction in hair Cr concentration was noticed over time in the rabbits fed sucrose, but changes were not noticed in the Zn concentrations. Cholelithiasis tended to be more severe in rabbits fed sucrose.

Effects of synthesized hard water and of cadmium in the drinking water upon lipid metabolism and cholelithiasis in rabbits.

Rabbits were fed a purified ration known to result in cholelithiasis and alterations in lipid metabolism. During a 12-week experimental period, either synthesized hard water (500 mg of Ca/L and 100 mg of Mg/L) or deionized distilled water were available as drinking water, and half of each of these groups of rabbits were also given 5 mg of Cd/L of water. Hair samples taken at the beginning and end of the experiment revealed an increase in the Ca concentration in rabbits given hard water, but no increase in Cd in rabbits given this element in the water. Cadmium in the drinking water resulted in accumulations of this element in liver and kidneys, and water hardness did not influence the amount of accumulation. Liver cholesterol concentrations and the severity of cholelithiasis were less in rabbits given Cd. The hard water administration resulted in lower liver cholesterol concentrations and less cholelithiasis. These results indicate that hard water does not reduce cardiovascular disease frequency by lessening Cd accumulation, but may affect cholesterol metabolism.

Influence of norethindrone on lipid metabolism and cholelithiasis in rabbits.

Rabbits were fed a purified ration containing 15% lard and were killed and examined at 0, 4, 8, 12, and 16 weeks. One group (group II) was given (treated) norethindrone in the ration (10 mg/kg of ration). There were no treatment effects noted on hepatic weight, percentages of dry matter and ether extract in liver, and hepatic cholesterol concentrations; however, there were some changes in the hepatic fatty acid percentages at some observation times. The occurrence and severity of cholelithiasis were not influenced by the treatment, but gallstone formation was pronounced in the 2 groups (ration alone, ration with added norethindrone) by the 4th weeks. The thoracic aorta did not reveal treatment effects as to weight and percentages of dry matter and ether extract, but the aortic cholesterol concentration was greater in the nontreated group than in the group fed the ration with the added norethindrone. Increased thoracic aortic weights were noted in both groups by the 4th week. Examinations and analyses of the adipose deposits forming the kidney pads did not reveal influences of time or treatment.

Influence in rats of dietary fats during the perinatal period: effects upon brain chemistry of dams and offspring.

Female rats were fed a purified ration containing 20% fat during gestation and lactation and the offspring were fed a commercial ration after weaning. The fat content of the purified ration was butter oil, a mixture of equal parts of butter oil and lard, or safflower oil. Brains of the dams were analyzed 1 month after parturition and brains of the offspring were analyzed when they were 20 weeks of age. Brains of the dams and offspring fed the safflower oil (about 75% linoleic acid) exhibited changes if comparisons were made with those fed other fats. In the dams, the percentage of cerebral weight as related to total brain weight was increased and the dry weight percentages of the cerebrum and brainstem were increased. In the cerebrums of male and female offspring, the DNA concentrations were increased and the RNA:DNA ration were decreased.

Influence in rats of dietary fats during the perinatal period: effects upon development and behavior of dams and offspring.

Female rats were fed purified rations containing 20% fat during gestation and lactation. The fat content was butter oil, an equal mixture of butter oil and lard, or safflower oil. Each litter size was reduced (at random) to 2 male and 2 female pups 1 day postpartum, and these offspring were feed a commercial ration after weaning and until they were 20 weeks of age. When dams were fed safflower oil, fewer of them produced litters after mating, and their behavior during lactation was less than optimal. Litter size and birth weights were similar in all dams producing litters. The type of fat fed to the dam in the perinatal period did not influence the growth, development, and spontaneous activity of the offspring. However, the offspring from the dams fed safflower oil exhibited poorer learning performance in a T-maze and sometimes had a longer time of inactivity following auditory stimulation than did the offspring from dams fed the other types of fats.

Influence of dietary fat upon rats during gestation and lactation.

A comparison was made between rats fed purified rations containing different fats during gestation and lactation and rats fed a commercial ration during similar periods. The purified ration containign 20% cocoa butter did not result in appreciable differences in the mothers (body weight, behavior, litter production, and brain chemistry) or in the 1-day-old neonates (brain chemistry). The purified ration containing 20% safflower oil resulted in fewer completed gestation, in poorer maternal behavior during lactation, and in neonates with small brains. A fat-free purified ration resulted in low brain concentrations of RNA and low RNA-DNA ratios in the mothers.

Influence of maternal dietary fat upon rat pups.

Mother rats were fed purified rations containing different fats during gestation and lactation and at 1 day after parturition. Litter sizes were reduced to 2 male and 2 female pups. The behavior and the brain chemical composition of these selected pups were compared with similarly selected pups from dams fed a commercial ration. All offspring were fed a commercial ration after weaning. Pups from dams fed 20% safflower oil were similar to controls. Feeding 20% cocoa butter to dams resulted in pups with reduced exploratory activity and with a rapid learning performance in a T-maze, employing the aversive stimulation of an electrical shock. Feeding dams a fat-free ration produced pups which had reduced rates of growth, small brains at 2 months of age, and low brain concentrations of cholesterol, DNA, and RNA.

Serum cholesterol concentrations and cholelithiasis in rabbits as influenced by the form of dietary fat.

Dietary fats of similar fatty acid composition but in different forms, i.e., olive oil and semipurified oleic acid, were fed to rabbits as 15% of a purified ration for 36 weeks. At periods during the experiment, cholesterol was added to the ration in different amounts. Females rabbits seemed to have greater serum cholesterol concentrations than did male rabbits, and the rabbits fed the oleic acid usually had greater concentrations than did those fed olive oil. After cholesterol was withdrawn from the ration, several weeks were required for the serum cholesterol concentrations to return to pretreatment values. Gallstones and hepatic fatty degeneration were found in rabbits fed either olive oil or oleic acid.