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Biomedical subjects

A W Mahoney

Publications and source records attributed to A W Mahoney.

At least 37 records · Page 2Linked to original sources
PubMed1984

Bioavailability to rats of calcium in meat products prepared from hand or mechanically deboned beef shank.

Mechanical deboning yields meat containing approximately 0.5% calcium. The bioavailability of the calcium in mechanically deboned meat ( MDM ) was compared to that from calcium carbonate fed in hand deboned meat ( HDM ) diets. Processing calcium carbonate with HDM into bologna, Thuringer or canned meat improved calcium bioavailability but did not increase the bioavailability of the calcium from MDM . The calcium absorptions were 62.7, 60.4 and 60.6%, respectively, from raw MDM , MDM bologna, MDM Thuringer and canned MDM . However, the percentage of calcium absorbed from calcium carbonate was increased slightly from 65.3, 65.9 and 65.6%, respectively, when it was processed as raw HDM , HDM bologna and Thuringer to 69.0% when processed as canned HDM . The bioavailability of the calcium in MDM was similar to that of calcium carbonate, whether expressed as apparent absorption or as relative biological value.

Absorption↗
PubMed1984

Effect of iron-deficiency anemia on percent blood volume in growing rats.

In determining iron bioavailability as iron gained in hemoglobin relative to intake, blood volume is calculated for the iron-deficient animals at the initiation of a feeding trial and again on the iron-repleted animals at the termination of the trial. However, the effect of iron deficiency on percent blood volume in the rats commonly used in iron repletion studies has not been determined. In experiment 1, we noted the relationship between body weight and blood volume in 18 randomly selected healthy male rats with a weight range of 95-278 g. In experiment 2, the in vivo disappearance of Evans blue dye from the plasma of 17 rats and the precision of the dye dilution method for estimating known volumes of heparinized rat blood were studied. From this information, linear regression equations were developed to more accurately estimate blood volume in vivo. In experiment 3, we studied blood volume relative to body weight in 122 weanling male rats at four levels of anemia. These animals were fed a low iron diet and bled to achieve anemia in 7 days. In the subsequent repletion interval, the rats were fed diets supplemented with ferrous sulfate for periods of 0, 5, 10 or 15 days, after which hemoglobin and blood volume were determined, and the animals were killed. Though body weight and blood volume were linearly correlated (r = 0.78), no such association existed between body weight and percent blood volume (r = 0.058). Blood volume held constant at 7.5 +/- 0.1 (mean +/- SE) percent of body weight in weanling prepubescent rats of 30-45 days of age regardless of iron status.

Anemia, Hypochromic↗
PubMed1984

Effects of folic acid malnutrition on rotaviral infection in mice.

A study was undertaken to determine if dietary deficiencies of folic acid would influence rotaviral diarrheal disease in infant mice. Female mice were fed diets containing essentially no folic acid, 25% of a normal quantity of folic acid, or a normally recommended quantity of folic acid, beginning at time of breeding and continuing through periods of gestation and lactation. Two-day-old infants from these dams were exposed to purified murine rotavirus or to sterile virus diluent and the severity of the rotaviral infection monitored. Infants from the low folic acid group had significantly lower folate levels in their livers, indicating a deficiency was achieved, and developed more severe disease manifestations than those infants from the dams receiving the normal folic acid levels in their diet. The infection enhancement was seen as increased incidences of diarrhea and a significantly greater number of mice exhibiting high intestinal rotaviral antigen titers. Serum rotavirus antibody titers were below detectable levels in a significant number of these same infants.

Animals↗
PubMed1983

Fasting and ketogenic diet effects on audiogenic seizures susceptibility of magnesium deficient rats.

Because fasting and ketogenic diets decrease seizure susceptibility in epileptics, their anticonvulsant effects were studied using sound-induced seizures in the magnesium-deficient rat. Fasting markedly depressed seizure incidence and severity but did not affect latency (sec to seizure onset). High-fat diet increased incidence of audiogenic seizures and seizure severity, and decreased latency. Gavage of medium chain triglyceride, beta-hydroxybutyrate or glucose did not affect seizure incidence, seizure severity or latency. Nonspecific excitability level was not associated with treatment nor with seizure incidence, severity or latency time.

Acoustic Stimulation↗
PubMed1983

Bioavailability of different sources of ferrous sulfate iron fed to anemic rats.

The bioavailability of iron from ferrous sulfate sources that had been stored for unknown periods was evaluated by using iron-deficient rats in experiment 1. The efficiency of converting dietary iron from these sources into hemoglobin varied from 60 to 84%. This variability was not explained on the basis of percent of iron in the ferrous state nor on the percent of iron in the source. The one fresh source used was reevaluated 3 months later, and its bioavailability had been reduced from 84 to 65%. The bioavailability of six fresh ferrous sulfate samples varied from 50 to 59% in experiment 2. It was concluded that, whenever ferrous sulfate is to be used as a reference source, fresh salt should be obtained to reduce variability among experiments.

Anemia, Hypochromic↗
PubMed1983

Bioavailability to anemic rats of iron from fresh, cooked or nitrosylated hemoglobin and myoglobin.

Bioavailabilities of heme iron prepared from lyophilized, fresh, cooked, nitrosylated hemoglobin and purified myoglobin in semipurified diets were investigated in two experiments. In experiment 1, the bioavailabilities of porcine and bovine hemoglobins were about one-third that for ferrous sulfate regardless of hemoglobin treatments. The efficiency of hemoglobin regeneration by anemic rats fed nitrosylated pork hemoglobin was significantly depressed compared with that by those fed unnitrosylated products. Cooking did not affect the availability of the heme iron, whereas washing tended to increase it. In experiment 2, the hemoglobin regeneration efficiency of the purified myoglobin diet was lower than reported by others for meat diets, and was even lower than that of the purified hemoglobin diet. The respective efficiency values for the basal, basal + FeSO4, hemoglobin, and myoglobin diets (experiment 2) were 0.073, 0.581, 0.199, and 0.125. The efficiencies of converting hemoglobin and ferrous sulfate iron into hemoglobin by the anemic rats were very similar to reported absorption values for these iron sources by iron-deficient human subjects.

Anemia↗
PubMed1983

Influence of malnutrition and alterations in dietary protein on murine rotaviral disease.

The possible correlation between malnutrition and degree of severity of rotavirus-associated infantile diarrhea which appears to occur in human populations was studied using a mouse model. To determine the effects of general malnutrition or altered levels of dietary protein, female mice were fed throughout pregnancy and infection periods with diets diluted with 0, 300, or 600 g glucose/kg, designated as normal nutrient to calorie ratio (N/C) diet, 70% N/C diet, or 40% N/C diet or with diets containing 75, 150, or 300 g casein/kg, as low-, normal-, or high-protein diets. Murine rotavirus was given by gavage to the 2-day-old offspring of these dams, and the extent of infection determined. Marked increases in severity of diarrheal disease were seen in the infants from dams receiving the 40 and 70% N/C diets and the low-protein diet. Severity of infection was seen as increased deaths, reduced weight gain, and increased passage of diarrheic feces. Intestinal viral levels and intestinal diarrhea scores did not vary appreciably. Serum interferon remained below detectable limits throughout the studies, but serum antibody was determined in dams 30 days post-virus exposure. The latter titers were lower in the infected mice from dams fed the 40 and 70% N/C diets, but were essentially the same in all the protein diet groups. Cross-fostering was done using the 40 and 100% N/C diets, wherein mice from dams fed either diet were placed on mothers fed the opposite diet. Increased severity of infection was again seen when the virus was given 2 days after the exchange, although the greatest infection occurred in animals from dams fed 40% N/C diet which were then fostered by other similarly fed dams. The increased host sensitivity to the rotaviral infection appeared to be a result of both pre- and postnatal dietary effects.

Animals↗
PubMed1980

Effect of atmospheric oxidation on bioavailability of meat iron and liver weights in rats.

Iron bioavailability of diets containing oxidized turkey and oxidized beef meat was investigated in two experiments. Lyophilized, uncooked turkey meat and beef meat were allowed to oxidize at room temperature. In experiment 1, rats were made anemic and fed diets containing uncooked lyophilized turkey meat which had been exposed to air for 0, 48, 96, 144, 216 or 264 hours. In experiment 2, anemic rats were fed diets composed of basal, basal + iron, basal + iron + formaldehyde, 100% fresh beef, 75% fresh-25% oxidized beef, 50% fresh-50% oxidized beef, 25% fresh-75% oxidized beef, 100% oxidized beef and 100% fresh beef + formaldehyde. The diets were prepared so that meat was the only source of iron. Hemoglobin regeneration served as the basis for measuring iron utilization. The length of oxidation time of the turkey meat did not significantly affect the growth of the rats or the bioavailability of the meat iron. Rats fed severely oxidized beef diets had decreased body weight, enlarged livers and depressed hematinic responses. Formaldehyde did not significantly affect iron utilization in rats fed basal diets, but depressed liver iron storage in rats fed fresh beef.

Anemia, Hypochromic↗
PubMed1980

Effects of level and source of dietary fat on the bioavailability of iron from turkey meat for the anemic rat.

The amount and source of fat in the diet can affect the growth response. Differences in growth among treatments an affect iron bioavailability determinations when change in hemoglobin concentration is used as the criterion. The amount and source of fat was varied in diets fed to anemic rats for assaying the bioavailability of iron from turkey meat. It was observed that gain in body weight increased as the amount of fat in the diet increased and concurrently, that the gain in hemoglobin concentration decreased. By expressing iron bioavailability as the efficiency of the conversion of dietary iron into hemoglobin, it was demonstrated that the amount of fat in the diet did not affect the bioavailability of iron from turkey meat or from ferrous sulfate. It was found that animals fed beef fat were most efficient at converting iron from turkey meat into hemoglobin followed by those fed turkey fat, corn oil and pork fat in descending order. Differences in liver iron concentrations among treatments were minimal even when the low-iron, basal diet treatment is included in the comparisons.

Anemia↗
PubMed1979

Effects of cerebral intraventricular magnesium injections and a low magnesium diet on nonspecific excitability level, audiogenic seizure susceptibility and serotonin.

Cerebral intraventricular injections of 17 and 50 microgram magnesium in artificial cerebrospinal fluid progressively depressed the Non-specific Excitability Level of permanently cannulated 150--200 g rats fed a low magnesium diet for 21 days. Compared with control diet, a low Mg diet caused an increase in brain serotonin. Weanling rats fed a low Mg diet for 2 weeks, then injected with 25 microgram Mg via acute cannulations, displayed reduced audiogenic seizure susceptibility compared with sham-injected controls.

Acoustic Stimulation↗
PubMed1978

Nutritional assessment of senior rural Utahns by biochemical and physical measurements.

Biochemical composition of blood and urine was used to evaluate the nutritional status of 187 ambulatory, older residents of five rural Utah communities. Measurements were also taken of height, weight, and blood pressure. The sample included 58 men and 129 women, with a mean age of 69 years. No deficiencies were observed for hemoglobin, hematocrit, and serum iron levels, although approximately 15% of the men had low levels for the first two indices. Serum mineral status for zinc, copper, sodium, potassium, magnesium, and calcium was adequate for most of the participants. Of the women 40% and of the men 21% had low serum total protein levels. No low serum levels of vitamin A and carotene were observed. Urinary excretion of riboflavin and thiamine was high for approximately 90% of the participants. Of the women 46% and of the men 37% had serum cholesterol values above 249 mg/100 ml of serum. One half of the women and 30% of the men were determined to be obese. Approximately one-fourth of both sexes had systolic pressures above 160 mm Hg.

Adult↗
PubMed1978

Preliminary report on the magnesium deficient rat as a model of epilepsy.

Weanling male rats fed a low magnesium diet for 14 days were protected from audiogenic seizures by administration of phenobarbital and diphenylhydantoin. Amphetamine, levo-dopa, and magnesium chloride injected 45 minutes prior to testing did not prevent the seizures. In contrast to weanling male rats which became mortally seizure prone, 3--5 week-old female rats fed a low magnesium diet for 17--21 days varied as to their susceptibility to audiogenic seizures. If thrown into seizures by a loud noise, the females frequently could be revived for subsequent testing, thus affording the opportunity to design experiments using fewer animals.

Age Factors↗
PubMed1976

Effect of magnesium deficiency on nonspecific excitability level (NEL) and audiogenic seizure susceptibility.

Magnesium deficiency in weanling rats caused an increase in NEL and in audiogenic seizure susceptibility. These behavioral effects were apparent after eight days of magnesium restriction and could be reversed by dietary rehabilitation. Serum magnesium declined rapidly from 1.87 +/- 0.10 mEq/L to 0.91 +/- 0.24 mEq/L in two days. Cerebrospinal fluid (CSF) magnesium decreased gradually from 1.86 mEq/L, becoming significantly lower (1.44 +/- 0.23 mEq/L) after eight days. When deficient rats were injected IP with MgCl2, raising the serum magnesium concentration to 6.6 mEq/L, NEL decreased to normal while audiogenic seizure susceptibility remained. Both NEL and audiogenic seizure susceptibility in rats reflect central nervous system magnesium concentration, except when serum magnesium concentration is very high. Very high serum magnesium concentration lowers NEL but does not reduce audiogenic seizure susceptibility if CSF magnesium is low.

Animals↗
PubMed1976

Effect of dietary iron level on efficiency of converting food iron into hemoglobin by the anemic rat.

The effects of varying the dietary levels of ferrous sulfate or ferric orthophosphate on the efficiency of the conversion of dietary iron into hemoglobin iron, was evaluated with the anemic rat. Weanling male rats were made anemic by feeding a semipurified diet containing 8.4 mg iron/kg, and by bleeding. They were divided into nine groups so that hemoglobin levels and body weights were similar. The rats were fed the basal diet or basal diet plus 12, 24, 36 and 48 mg iron/kg diet provided as ferrous sulfate or ferric orthophosphate. The rats were fed 10 g daily of the respective diets for 10 consecutive days. The efficiency of the conversion of dietary iron into hemoglobin iron was not significantly affected by dietary level of either iron salt. It was determined that ferric orthophosphate was 51% as efficient as ferrous sulfate for hemoglobin regeneration in the anemic rat.

Anemia↗
PubMed1975

Utilization of dietary calcium by iron-deficient rats.

Iron deficiency causes cytological and enzymic changes in the gastrointestinal mucosa of animals and man that can be expected to impair the digestion and absorption of other nutrients. In experiment 1, healthy, weanling, female rats were grouped into pair-mates and pair-fed either an iron-deficient or an iron-supplemented diet for 19 weeks. In experiment 2, iron-deficient offspring reared by iron-deficient females were grouped into pair-mates and pair-fed either an iron-deficient or an iron-supplemented diet for 15 weeks. In experiment 1, apparent absorption of calcium was significantly depressed in week 9 (p less than 0.001) and slightly depressed in weeks 10 and 11. In experiment 2, the apparent absorption of calcium was significantly (p less than 0.001) depressed in weeks 6, 13, and 14. Absorption was not measured in other weeks in these experiments. The concentrations of calcium and magnesium were consistently higher in the fecal dry matter of the iron deficient rats in both experiments. It was concluded that any defects in digestion and absorption by the iron-deficient rats was confined primarily to the mineral nutrients because in both experiments apparent absorption of dry matter was consistently higher in these animals compared to their iron-supplemented pair-mates.

Animals↗
PubMed1975

Effects of calcium solubility on adsorption by rats with induced achlorhydria.

Gastric X-irradiated, achlorhydric rats and sham-operated controls were fed diets containing very soluble calcium chloride or calcium gluconate or slightly soluble calcium carbonate or tricalcium phosphate for 3 weeks. Calcium was absorbed more efficiently by achlorhydric rats from the very soluble salts from the slihtly soluble salts. The control rats absorbed calcium from the very soluble and slightly soluble calcium salts with similar efficiency. Achlorhydric rats fed slightly soluble calcium salts developed weaker bones with a lower mineral content than did those fed very soluble calcium. Apparently, the very soluble dietary calcium offset the impaired calcium absorption of achlorhydric rats. Calcium solubility had no significant effect on the bones of control animals.

Achlorhydria↗