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Biomedical subjects

M Fields

Publications and source records attributed to M Fields.

At least 73 records · Page 4Linked to original sources
PubMed1989

Dietary fructose as compared to glucose and starch increases the calcium content of kidney of magnesium-deficient rats.

The effects of feeding diets containing fructose, glucose or starch with or without added magnesium (Mg) on tissue levels of calcium (Ca) in weanling rats were investigated. Rats were fed their respective diet for 4 wk and then fasted overnight. After decapitation, blood was immediately collected, and liver, kidney and heart were removed to determine their Mg and Ca content. Relative kidney and liver weights were greatest in the rats fed the fructose diet. Hypomagnesemia was observed in all animals fed a Mg-deficient diet regardless of carbohydrate source (1.71 vs. 2.27 mg Mg/dl plasma for Mg-deficient vs. Mg-adequate groups, respectively). Among Mg-deficient groups, starch-fed rats had the highest level of plasma Mg, while fructose-fed rats had the highest level of kidney Mg. Although plasma and liver Ca levels were not significantly different among the groups, Ca content of the kidney and heart was greatest in animals fed a Mg-deficient diet with fructose. This was especially evident in the Ca content of the kidney, which was 8- to 9-fold greater than that of all other experimental groups. The results of the present study demonstrate the presence of a synergistic interaction between fructose and Mg deficiency that increases Ca levels in certain soft tissues, especially the kidney.

Animals↗
PubMed1989

Surgical glove perforation in dermatologic surgery.

Twenty-eight of 240 (11.7%) pairs of sterile surgical gloves collected from dermatologic surgery clinics had perforations. Only 17.1% of these perforations were known to the wearer at the time of surgery. Equal numbers of perforations were found in gloves of operators and assistants. Perforations were more numerous in dominant-handed gloves. Dermatologic surgeons should consider the incidence of unknown glove perforation when planning surgeries in patients with infectious diseases.

Dermatologic Surgical Procedures↗
PubMed1989

Coverage gaps in seat belt use laws.

Some seat belt use laws exempt occupants in certain seating positions and in certain types of vehicles, or both. A state-by-state analysis was conducted of the extent to which passenger vehicle occupants killed before the laws went into effect would have been covered by the laws subsequently passed. Only five states had laws that covered all passenger vehicle occupants; the majority excluded 4 to 8 per cent and six states excluded 14 per cent or more. More inclusive laws can reduce injuries and save lives.

Accidents, Traffic↗
PubMed1989

Blood risk factor metabolites associated with heart disease and myocardial fatty acids in copper-deficient male and female rats.

Intact and castrated males and intact and ovariectomized female rats were fed a copper-deficient diet in order to establish whether the protection provided in females against cardiovascular pathology and mortality is due to endogenous sex hormones, and different levels of blood lipids and/or myocardial fatty acids. Seventy-three male and female rats were assigned to a copper-deficient diet (0.6 micrograms of copper/g diet) containing 62% fructose for 8 weeks. Twelve of the male rats underwent castration and 12 of the females were ovariectomized. All animals exhibited high levels of plasma cholesterol, triglycerides, and uric acid, which were neither affected by the sex of the rat nor by the surgical treatment. The composition of fatty acids of the myocardium was similar in males and females. Except for those animals that were sacrificed by us, all other male rats died of heart pathology. In contrast, none of the female rats exhibited heart pathology and none died of the deficiency. It is suggested that heart pathology and mortality in copper deficiency are sex related and not due to high levels of plasma cholesterol, triglycerides, and uric acid or to differences in myocardial fatty acid composition.

Animals↗
PubMed1989

Fatal crash involvement and laws against alcohol-impaired driving.

It is estimated that in 1985 about 1,560 fewer drivers were involved in fatal crashes because of three types of drinking-driving laws. The laws studied were per se laws that define driving under the influence using blood alcohol concentration (BAC) thresholds; laws that provide for administrative license suspension or revocation prior to conviction for driving under the influence (often referred to as "administrative per se" laws); and laws that mandate jail or community service for first convictions of driving under the influence. It is estimated that if all 48 of the contiguous states adopted laws similar to those studied here, and if these new laws had effects comparable to those reported here, another 2,600 fatal driver involvements could be prevented each year. During hours when typically at least half of all fatally injured drivers have a BAC over 0.10 percent, administrative suspension/revocation is estimated to reduce the involvement of drivers in fatal crashes by about 9 percent; during the same hours, first offense mandatory jail/community service laws are estimated to have reduced driver involvement by about 6 percent. The effect of per se laws was estimated to be a 6 percent reduction during hours when fatal crashes typically are less likely to involve alcohol. These results are based on analyses of drivers involved in fatal crashes in the 48 contiguous states of the United States during the years 1978 to 1985.

Accidents, Traffic↗
PubMed1988

Dietary fructose exacerbates the cardiac abnormalities of copper deficiency in rats.

Copper deficiency has been shown to result in severe cardiovascular lesions in several species of animals. The principal carbohydrate in the copper-deficient diet most often used with rats is sucrose, which is known to have adverse effects on carbohydrate and lipid metabolism and thus may contribute to cardiovascular disorders. These observations prompted experiments in which starch and fructose were substituted for sucrose in a copper-deficient diet, to see if the effects of the copper deficiency might be modified. In the hearts from rats fed copper-deficient diets with fructose or sucrose, there was marked, mostly ventricular hypertrophy, and mild to severe myocardial inflammation, degeneration, and fibrosis. Aneurysm of the left ventricle and pericarditis also were common. Hearts from the starch, copper-deficient groups were much less hypertrophic, and very few were affected by myocardial inflammation, degeneration, or fibrosis. Defects of elastin or other structures were not observed in the aortas or pulmonary or coronary arteries of any specimens.

Animals↗
PubMed1988

Changes in pancreatic enzyme specific activities of rats fed a high-fructose, low-copper diet.

This study describes the progressive changes in exocrine pancreatic enzyme specific activities from rats provided with a diet containing either 62% starch (S) or fructose (F) with 6.0 ppm copper (+Cu) or 0.6 ppm (-Cu) from 21 to 61 days of age. Copper-deficient rats had significantly reduced pancreatic weight and DNA, RNA, protein and copper content and superoxide dismutase (SOD) activity after consuming diet for 39 days. These reductions were far more severe in F-Cu than in S-Cu rats. Copper deficiency significantly reduced pancreatic amylase and lipase specific activities, but the effect was more severe in the F-Cu dietary group. Chymotrypsinogen and trypsinogen specific activities were reduced only in the F-Cu dietary group and the CHO x Cu interaction was significant. High dietary fructose and low dietary copper in combination interact to produce severe reductions in pancreatic amylase, lipase, chymotrypsinogen, and trypsinogen specific activities which could not be explained by either copper deficiency or by an increase in dietary fructose alone.

Amylases↗
PubMed1987

Expression of the oxytocin gene in the large cells of the bovine corpus luteum.

In the bovine ovary there is a delay of 4-6 days between the observed maximum of oxytocin mRNA and the peak in the luteal levels of oxytocin nonapeptide. This implies a maturation process involving components of the post-translational processing pathway. In situ hybridization shows the oxytocin gene to be transcribed exclusively in the large cells of the corpus luteum at the beginning of the estrous cycle.

Animals↗
PubMed1987

Lack of an effect of dietary fructose on severity of zinc deficiency in rats.

Because feeding rats diets containing fructose as the carbohydrate source reduces copper and selenium status, we investigated whether the type of dietary carbohydrate also affected indices of zinc status. The experimental design was a 2 X 2 factorial study with the source of dietary carbohydrate (cornstarch or fructose) and the level of dietary zinc (0.7 or 31 micrograms Zn/g) as the variables. The experiment utilized 76 weanling male Sprague-Dawley rats randomly assigned to one of four dietary groups. Animals fed a zinc-deficient fructose diet were allowed to consume the diet ad libitum; all other groups were pair-fed to that group to ensure equivalent nutrient and energy intake. The results of the 29-d study showed that the most sensitive indices of zinc status measured, including growth, survival and the zinc concentrations of plasma, femur and testes, were not affected by the type of dietary carbohydrate. This lack of an effect of fructose on the zinc status of the experimental animals indicates that the ability of fructose to exacerbate copper and selenium deficiencies is specific, rather than representing a generalized effect of this simple sugar on the requirements and/or metabolism of all essential trace elements.

Animals↗
PubMed1987

Alteration of pancreatic enzyme activities in small intestine of rats fed a high fructose, low copper diet.

This study describes the progressive effects on pancreatic enzyme activities from washings of the small intestine of rats fed diets containing either 62% starch (S) or fructose (F), with 0.6 mg copper/kg diet (-Cu) or 6.0 mg copper/kg diet (+Cu) from 21 to 61 d of age. Hepatic copper concentration of the copper-deficient groups was 50% of that of the copper-supplemented groups. Body and relative pancreatic weights were lower in the F-Cu dietary group than in any other group. Relative liver weight was significantly higher in the fructose dietary groups than in the starch dietary groups. There were significant carbohydrate (CHO) X week and Cu X week interactions for luminal amylase activities and the CHO X Cu X week interaction was significant for luminal lipase and trypsin activities. The lowest enzyme activities were observed in the F-Cu-fed rats. The CHO X week interaction was significant for chymotrypsin with the lowest enzyme activities in the fructose-fed rats. It appears that high dietary fructose and low dietary copper interact to produce greatly reduced pancreatic enzyme activities in small intestinal washings. We speculate that subsequent digestive and absorptive abnormalities during a period of rapid growth may account for the severe morbidity and mortality in copper-deficient, fructose-fed rats.

Amylases↗
PubMed1987

Sexual differences in the expression of copper deficiency in rats.

The present investigation was undertaken to establish whether the severity of copper deficiency in rats fed diets containing fructose is affected by the presence and type of endogenous sex hormones. Intact and castrated male rats and intact and ovariectomized females were fed from weaning a copper-deficient diet (0.6 ppm) containing 62% fructose for 8 weeks. Regardless of castration, male rats were anemic, exhibited heart hypertrophy, and died of the deficiency. However, castration ameliorated the anemia and delayed the mortality. In contrast, none of the females died of the deficiency. It is suggested that in addition to the sex of the animal, levels of testosterone in the male may also play a role in the severity of copper deficiency.

Animals↗
PubMed1986

Effects of sugars on indices of glucose tolerance in humans.

Ten men and nine women were studied to determine whether replacement of utilizable complex carbohydrate by sugars (mono- and disaccharides) in a high-fiber, low-saturated fat diet would affect indices of glucose tolerance. Diets differed in that the 50% of calories derived from carbohydrate was either 35% complex and 15% sugars (low-sugar) on 15% complex and 35% sugars (high-sugar). Summation of glucose responses 30-180 min following an oral glucose tolerance test was significantly higher in men, but not women, after they consumed the high-sugar diet. Corresponding insulin responses were significantly higher in men consuming the high-sugar compared to the low-sugar diet. Insulin binding was significantly lower during the base line period and after the high-sugar diet compared to the low-sugar diet. Results indicate that sugars adversely affect indices of glucose tolerance when they replace complex carbohydrates even in a high-fiber, low-saturated fat diet.

Adult↗
PubMed1986

Contrasting effects of the stomach and small intestine of rats on copper absorption.

Since the severity of copper deficiency has been shown to be enhanced by feeding diets containing fructose but ameliorated by diets containing starch, we decided to investigate the effect of fructose or starch on copper absorption. As copper transport has been reported to occur also from the stomach, it was possible that copper absorption is inhibited by fructose already from that tissue. Under anesthesia, stomachs of 72 rats fed copper-deficient or supplemented diets containing fructose or starch were ligated prior to the oral administration of 64Cu. Gastric absorption of 64Cu was studied when the isotope was administered by gastric tube either in diet containing fructose or starch or in water. 64Cu was not absorbed from the stomach regardless of the type of dietary treatment, copper status or whether the copper was administered either in diet or in water. In addition, the absorption of 64Cu from a diet containing either fructose or starch or from a saline solution was studied using the isolated ligated duodenal loop. When 64Cu was administered with dietary fructose 64Cu retention and absorption were impaired when compared to starch. When 64Cu was administered in saline solution, differences in retention and absorption between the four dietary groups disappeared. It is suggested that the requirements for copper rather than the decreased absorption of copper are responsible at least in part for the more pronounced severity of copper deficiency in rats fed fructose compared to those fed starch.

Absorption↗
PubMed1986

Effect of fructose or starch on copper-67 absorption and excretion by the rat.

Studies with 67Cu were conducted with copper-deficient or supplemented rats fed fructose or starch in an effort to investigate the effects of different dietary carbohydrates and inadequate copper intake on the absorption, tissue distribution and excretion of copper. After being fed their diets for 5 wk, they were killed at 8, 24, 48 and 96 h following the intubation of their respective copper-supplemented diets extrinsically labeled with 67Cu. Only at 48 and 96 h following the intubation of 67Cu, the gastrointestinal (GI) contents of rats fed the copper-deficient fructose diet exhibited higher radioactivity than rats fed the copper-deficient starch diet. Although not always significant, this apparent retention of copper in GI contents was accompanied by decreased whole-body radioactivity and depressed urinary excretion. The cumulative excretion of 67Cu via feces over the 96-h period of collection was similar for both groups of copper-deficient rats, regardless of whether the dietary carbohydrate was fructose or starch. The data suggest that the more severe copper deficiency is related to the sustained higher level of radioactivity in the GI contents. This increased retention of 67Cu in GI contents suggests impaired absorption of copper.

Animals↗
PubMed1986

Tissue distribution and excretion of copper-67 intraperitoneally administered to rats fed fructose or starch.

It has been suggested that impaired gut absorption of copper is the cause of the exacerbated copper deficiency signs in rats fed fructose when compared to rats fed starch. The present study was designed to examine how rats fed fructose or starch diets, either copper-deficient or supplemented, distributed and excreted 67Cu when the isotope was administered i.p. Intraperitoneal administration was chosen in an effort to circumvent primary gut absorption as a factor in the metabolism of 67Cu. After 7 wk of dietary treatment, rats received an i.p. injection of 67Cu and were placed in metabolic cages for 4 d. Regardless of dietary carbohydrate, copper-deficient rats retained similar levels of radioactivity in various tissues and excreted similar amounts of 67Cu in feces and urine. This similarity in copper metabolism in copper-deficient rats fed either fructose or starch when the gut was circumvented for isotope administration suggests that the gut could be responsible, at least in part, for the exacerbated signs associated with the copper deficiency in rats fed fructose. The possibility is discussed that alterations in metabolism may increase the requirement for copper when fructose is the main dietary carbohydrate.

Administration, Oral↗
PubMed1986

Insulin is released from rat brain neuronal cells in culture.

Depolarization of neuronal cells in primary culture from the rat brain by potassium ions in the presence of calcium or by veratridine caused a greater than three-fold stimulation of release of immunoreactive insulin. HPLC of the released insulin immunoreactivity from the neuronal cultures comigrated with the two rat insulins. The depolarization-induced release of insulin was inhibited by cycloheximide and was specific for neuronal cultures since potassium ions failed to cause the release in comparably prepared astrocytic glial cells from the rat brain. Prelabelling of neuronal cultures with [3H]leucine followed by depolarization resulted in the release of radioactivity that immunoprecipitated with insulin antibody. The release of [3H]insulin was biphasic. These observations suggest that neuronal cells from the brain have the capacity to synthesize insulin that could be released under depolarization conditions.

Animals↗
PubMed1986

Development of copper deficiency in rats fed fructose or starch: weekly measurements of copper indices in blood.

Copper deficiency was induced in weanling rats fed diets whose sole source of carbohydrates was starch or fructose for 7 weeks. Conventional parameters of copper status, plasma copper concentrations, ceruloplasmin activity, and erythrocyte superoxide dismutase (SOD) activity were longitudinally monitored weekly to follow the development of the deficiency and to correlate these indices with the degree of severity of the deficiency. Although 30% of the rats fed a copper-deficient fructose diet died and no deaths occurred in rats fed the copper-deficient starch diet, plasma copper, ceruloplasmin, and SOD activities were reduced to a similar extent in all rats fed copper-deficient diets regardless of the type of dietary carbohydrate. Thus, none of the indices used accurately reflected the greater degree of deficiency or mortality in rats fed the fructose diet deficient in copper. The results of the present study underscore the need for more sensitive tests or alternative parameters to assess copper status in living animals.

Animals↗