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Biomedical subjects

M F Sullivan

Publications and source records attributed to M F Sullivan.

At least 37 records · Page 2Linked to original sources
PubMed1985

Further studies on the influence of chemical form and dose on absorptions of Np, Pu, Am and Cm from the gastrointestinal tracts of adult and neonatal rodents.

Absorption of isotopes of the actinide elements Np, Pu, Am and Cm from various organic media and/or in combination with plant or animal ligands or tissue is compared with their absorption from an inorganic nitrate medium. Gastrointestinal (GI) transport of 238Pu, 239Pu, 241Am and 244Cm at high concentrations from citrate medium by adult rats and/or mice was higher than from nitric acid medium. Neptunium-237 absorption, however, was not increased by citrate; probably because its oxidation state was reduced from 237Np(V) to 237Np(IV) by the medium and by the GI content. Increasing the mass of the 237Np dose resulted in increased absorption. Neither incorporation of 238Pu in rat liver nor retention of 238Pu oxide in rat lungs enhanced absorption when those Pu-containing tissues were administered intragastrically to either adult or neonatal rats. Ranking of GI absorption of the various forms of Pu gavaged in these studies suggests that transport is in the order: Pu citrate greater than Pu phytate greater than biologically incorporated Pu greater than Pu nitrate.

Actinoid Series Elements↗
PubMed1985

Preoperative crossmatch ordering and blood use in elective hysterectomy.

Preoperative crossmatch guidelines have been shown to improve crossmatch ordering practices. To refine crossmatch ordering, specific characteristics of 258 patients who underwent abdominal hysterectomy and 277 patients who underwent vaginal hysterectomy were correlated with blood transfusion by univariate and multivariate analyses. Abdominal hysterectomy patients with pelvic inflammatory disease with adhesions and/or abscess were significantly more likely to require blood transfusion. Specimen weight correlated significantly with blood transfusion only for patients with ovarian pathology. Blood use was independently correlated with reduced preoperative hemoglobin and with estimated blood loss. Vaginal hysterectomy patients who had a colporrhaphy were more likely to require blood transfusion. Preoperative crossmatch recommendations made on the basis of these results reduce costs and increase the efficiency of predeposit autologous transfusion programs and preoperative crossmatch ordering practices.

Abscess↗
PubMed1984

Gastrointestinal absorption of metals (51Cr, 65Zn, 95mTc, 109Cd, 113Sn, 147Pm, and 238Pu) by rats and swine.

Adult and neonatal rats and neonatal pigs were gavaged with solutions of metal radionuclides to determine gastrointestinal absorption. Zinc-65 and technetium-95m were well-absorbed by both age groups; chromium-51, cadmium-109, tin-113, promethium-147, and plutonium-238 were not. The quantities of the poorly absorbed metals that were absorbed by neonates were between 4 and 100 times higher than those absorbed by adult rats. Autoradiograms prepared from the entire small intestine of the neonatal rat showed that 109Cd was retained in the duodenum. In contrast, measurements in the piglets showed much higher 109Cd retention in the ileum than in the duodenum. Autoradiograms and radiochemical measurements of 147Pm and 238Pu in both neonatal rats and swine showed the highest level of retention in the ileum. The results indicate that, for most of the metals studied, absorption from the gastrointestinal tract is substantially higher for neonatal than for adult rats.

Age Factors↗
PubMed1984

Absorption and distribution of cadmium in mice fed diets containing either inorganic or oyster-incorporated cadmium.

To determine the absorption, organ distribution, and retention of organically bound cadmium (Cd) and the effects of dietary zinc (Zn) on Cd metabolism, groups of mice were fed five different diets. The organic Cd used in the diets was in the form of lyophilized oyster (Crassostrea virginica) that had accumulated radiolabeled 109Cd through a plankton food chain. The mice were fed either a standard basal mouse diet (AIN-76) or diets containing five or eight times the Zn concentration of the basal diet. The source of Zn was either oyster tissue or ZnCO3. The concentration of organic and inorganic Cd provided a dose of approximately 0.4 mg/kg. Diets prepared from oyster tissue probably contained all of the Cd and 85% of the Zn in organic form. Diets prepared with inorganic metals contained about the same Cd and Zn concentrations as the diets prepared with oyster. There was very little difference between the retention of Cd by mice that ingested organic (oyster bound) Cd and those fed inorganic Cd (CdCl2). However, when the Cd retained in the intestine was excluded, retention of organic Cd was significantly greater than that of inorganic Cd. The organ distribution of Cd differed significantly according to the chemical form of Cd fed (organic or inorganic) and the Zn level in the diet. The kidneys of mice fed organically bound Cd retained a higher percentage of the metal than the kidneys of those fed inorganic Cd. On the other hand, the livers of animals fed a low-Zn diet retained a higher percentage of the Cd than the livers of those fed a high-Zn diet, regardless of the dietary source of Cd.

Absorption↗
PubMed1984

Effects of fasting and/or oxidizing and reducing agents on absorption of neptunium from the gastrointestinal tract of mice and adult or neonatal rats.

Neptunium-237(V) nitrate was administered by gavage to groups of fed or fasted adult and 5-day-old rats. Some groups also received the oxidants quinhydrone or ferric iron, and others received the reducing agent ferrous iron. Adult mice received ferric or ferrous iron and 235Np. When the adult rats were killed at 7 days after gavage, measurements showed that, compared with rats that were fed, a 24-hr fast caused a fivefold increase in 237Np absorption and retention. Both quinhydrone and ferric iron caused an even greater increase in absorption in both fed and fasted rats. Ferrous iron, on the other hand, decreased absorption in fasted rats to values lower than those obtained in fed rats. Similar results were obtained in mice treated with 235Np and either ferric or ferrous iron. The highest absorption obtained after gavage of ferric iron to fasted rats and mice was about two orders of magnitude higher than the value obtained in animals that were fed before gavage. The effects of ferric and ferrous iron on neptunium absorption by neonatal rats were similar to their effects on adult animals but of lesser magnitude. These results are consistent with the hypothesis that Np(V), when given in small mass quantities to fed animals, is reduced in the gastrointestinal tract to Np(IV), which is less well absorbed than Np(V).

Aging↗
PubMed1983

Can information on the gastrointestinal absorption of actinide elements by neonatal rats, guinea pigs, dogs and swine be extrapolated to man?

Neonatal mammals that acquire passive immunity by absorbing immunoglobulins from mother's milk (colostrum), as well as species that develop immunity prenatally, absorb macromolecules from the gut. This permeability of the GI tract to large molecules also serves as a route of entry for actinides in quantities greatly in excess of adult absorption. Administration of 238Pu nitrate to piglets results in absorption that is 1000 times the adult value but neonatal dogs, guinea pigs and rats absorb only 100 times more 238Pu than adults. Neonatal pigs and rats retain as much as 60% of the dose in the gut mucosa for several days but dogs and guinea pigs retain much less. We have also found this difference in GI tract 238Pu retention to occur after inhalation, indicating that the gut is an important route of entry for actinides that are inhaled by neonates. Although retention of different gavaged actinides by suckling rats is within the same range (1-3%) we found retention by piglets to range between 35% for 233U and about 2% for 237Np, 244Cm and 241Am nitrate. Piglets that were gavaged with 238Pu nitrate retained 19% in the liver and carcass a week later. After one year, half of that still remained. Neonatal rats, on the other hand, retained 3% initially and only 0.1% at one year. While the GI tract of the human infant is probably not nearly as permeable to macromolecules as that of the swine, it is known to be more permeable to macromolecules than that of the adult human. If actinide absorption is also increased in the child, the retention of these elements would probably be more like that in swine than in rats, because of the greater similarity between man and swine in skeletal maturation, in retention of actinides in liver and their longer life span. These studies suggest a need for further information on neonatal absorption of actinides in a large animal species that has a developing GI function more similar to that of humans.

Actinoid Series Elements↗
PubMed1983

Nutritional influences on plutonium absorption from the gastrointestinal tract of the rat.

Rats that were fasted and/or fed diets consisting of whole milk, dry milk, milk supplement, orange juice, low calcium, or low vitamin D were gavaged with 238Pu nitrate to measure plutonium absorption. All dietary variations resulted in increases in both absorption and retention. The increases ranged between 2 and 20 times the absorption values obtained for rats fed commercial chow. Sucklings of dams fed a calcium-deficient diet also exhibited increased 238Pu absorption. The results indicate that nutrition is an important factor influencing gastrointestinal absorption of plutonium.

Animal Nutritional Physiological Phenomena↗
PubMed1983

The effect of mass on the gastrointestinal absorption of plutonium and neptunium.

Absorption and retention of plutonium were determined in mice after intragastric administration of either 6 X 10(-4) or 1.5 mg/kg in bicarbonate, citrate, or nitrate media. At the higher concentration, absorption of the citrate was greater than that of the nitrate; at the lower concentration, chemical form was not an important factor in absorption. Concentration and chemical form had much less influence on absorption by the neonatal (versus the adult) rat. The transfer factor (f1) for neonates was between one and two orders of magnitude higher than for adults. Absorption and retention of neptunium were determined in rats and/or mice after intragastric administration at doses ranging from 2.2 X 10(-7) to 43 mg/kg in nitrate solutions of pH 1.5. At the higher concentrations, absorption was 1.5 to 2.7%. For lower concentrations, absorption was 25 to 65 times less. In contrast to results obtained in adult animals, absorption of neptunium by neonates decreased with increasing dose. The data obtained in adult animals suggest that the f1 factor recommended by the ICRP for plutonium should be increased by a factor of 10, but the neptunium f1 factor, in contrast, should be decreased by a factor of 10.

Animals↗
PubMed1983

The effect of X rays, DTPA, and aspirin on the absorption of plutonium from the gastrointestinal tract of rats.

To measure the effect of radiation on plutonium transport, rats that were exposed to 250-kVp X rays were given 238Pu 3 days afterwards by either gavage or injection into a ligated segment of the duodenum. In a second group of experiments, rats were either injected intraduodenally with 238Pu-DTPA or administered the chelate intravenously and the 238Pu by gavage. In a third experiment, rats that had been gavaged with 200 or 400 mg/kg/day of aspirin for 2 days were injected intragastrically with 238Pu nitrate. Results of the first experiment showed a dose-dependent increase in 238Pu absorption between 800 and 1500 rad of lower-body X irradiation. Intravenous or intraduodenal injections of DTPA caused a marked increase in 238Pu absorption but resulted in decreased plutonium deposition in the skeleton and liver. Retention of 238Pu in the skeleton of rats given aspirin was double that of controls, but the effect on plutonium absorption was less marked than that of DTPA.

Animals↗
PubMed1982

Further studies on the absorption of actinide elements from the gastrointestinal tract of neonatal animals.

Plutonium retention was measured after intragastric administration to neonatal rats, dogs and swine. At 1 week after administration, substantially more of the actinide remained in swine and dogs than in rats. The quantity of 238Pu absorbed by piglets was markedly influenced by such factors as compound solubility, mass of plutonium administered, oxidation state of the actinide, and age of the animal at gavage. Cortisone treatment reduced absorption, but was less effective in piglets than in neonatal rats. Measurements of 238Pu transport from ligated segments of the neonatal swine intestine indicated highest absorption from the duodenum, where the actinide was shown, autoradiographically, to be deposited in the epithelial region; in the ileum, deposition was predominantly in the lacteal region. Absorption of actinides by neonatal swine decreased in the order of 233U greater than 238Pu greater than 237Np greater than 244Cm greater than 241Am. Measurements at 1 yr after gavage showed a much higher retention by swine than by rats.

Actinoid Series Elements↗
PubMed1981

Partial undercutting facetectomy for bony entrapment of the lumbar nerve root.

Seventy-eight patients who had been operated on for bony entrapment of lumbar nerve roots were studied in an attempt to define the clinical syndrome, and to assess the results of a new technique of decompression which preserves spinal stability. The mean age of the patients was 45 years and 28 of them had previously undergone spinal operations. Pain in the leg was the predominant symptom, with evidence of motor involvement in half of the patients. Signs of nerve root tension were found in only one-third of the patients. The principal factor in the aetiology was degenerative change in the posterior facet joints. Decompression was achieved by a partial undercutting facetectomy. Fifty-nine per cent of the patients obtained a "good" result and 85 per cent were satisfied with the result of their operation. Successful partial facetectomy for bony entrapment of lumbar nerve roots produced rapid and lasting relief of pain.

Adult↗