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Biomedical subjects

T M Sullivan

Publications and source records attributed to T M Sullivan.

52 records · Page 3Linked to original sources
PubMed1986

Glucose ameliorates the depletion of NADPH by paraquat in rat lung slices.

Paraquat-stimulated NADPH depletion in rat lung slices is responsive to exogenous glucose concentration. Lung slices incubated with 11 mM glucose and 10(-4) M paraquat had a 40% lower NADPH/NADP+ ratio than did control lung slices. Incubation with no added glucose and 10(-5) M paraquat caused a 41% decrease in NADPH/NADP+. With paraquat at 10(-5) M, glucose at 1.1, 5.5, 11, or 22 mM increased NADPH/NADP+ ratios in a concentration-dependent manner until, at 22 mM glucose, the effect of paraquat was prevented. The sum of NADP+ plus NADPH was only 60% of control with 10(-5) M paraquat and no glucose. However, with any concentration of glucose from 1.1 to 22 mM, the total was 92% of control. The results indicate that glucose may be beneficial in preventing paraquat-mediated NADPH depletion in rat lung slices.

Animals↗
PubMed1984

Ascorbic acid nutritional status does not affect the biochemical response to paraquat.

Guinea pigs were subjected to dietary control of ascorbic acid intake to produce deficient, normal, and supplemented tissue ascorbate concentrations. Paraquat, a potent pulmonary toxin, was then administered. Tissue distribution and covalent binding of paraquat were not affected significantly by ascorbate nutritional status except for decreased 24-hr kidney burdens in deficient animals. Paraquat increased pulmonary thiobarbituric acid reactivity and mixed disulfide formation, but no evidence of either a protective or a potentiative interaction of endogenous ascorbate and paraquat was observed. This study indicates that alteration of endogenous ascorbic acid levels does not alter the biochemical response to paraquat.

Analysis of Variance↗
PubMed1983

The pharmacokinetics of inhaled chlorobenzene in the rat.

Male rats were exposed for 8 hr/day to 100, 400, or 700 ppm of [14C]chlorobenzene vapor for either 1 or 5 days for the purpose of examining the dose dependency of parameters indicative of the toxicity process and the effect of repeated exposure. 14C burdens in the blood, liver, kidneys, lungs, and fat were measured at 0, 16, and 48 hr after exposure. The labeled material excreted in the urine and expired air was collected for 48 hr. Analysis was performed on both the rats and total amounts eliminated. The mercapturic acid percentage of the urinary metabolites excreted in the first 24 hr was measured. The 14C burdens of all tissues increased in proportion to increased exposure concentrations, except for adipose tissue burdens, which increased more than 30-fold between 100 and 700 ppm. Respiratory elimination of 14C also increased disproportionately. The urinary metabolite profile was altered, with a dose-dependent decreased in the mercapturic acid percentage from 68% at 100 ppm to 51% at 700 ppm. Changes due to multiple versus single exposures were higher tissue burdens 48 hr after exposure, less total excretion of label, a lesser percentage of the total excreted through respiration, and a change in the rate of respiratory excretion. The dose-dependent changes are postulated to be due to saturation of the metabolic elimination of chlorobenzene. The effect of multiple exposure is apparently some stimulation of metabolism.

Animals↗
PubMed1981

An experimental evaluation of endodontic procedures and filling materials.

Radionuclide imaging was evaluated as a diagnostic tool in predicting the outcomes of endodontic procedures. Endodontic techniques intended to produce successful or unsuccessful results were performed on the molars of six dogs, and the effects on apical tissues were followed radiographically and by imaging over a 14-week period. Abnormally high uptake of radionuclides was observed during the first month following treatment in all teeth, regardless of the technique used. Persistent high uptake beyond that time was found to be associated with a failing course of therapy. Various root canal filling materials were also tested for their effects on bone formation in a rabbit model of healing bone. Experimental bone formation was inhibited by two commercial canal cements but not by either gutta-percha or silver points. It was tentatively concluded that the inhibitory effect of cements may serve to suppress heightened bone turnover associated with apical breakdown.

Alveolar Process↗
PubMed1981

The biocompatibility of dental implant materials measured in an animal model.

The biocompatibility of two implant materials, vitallium and poly-methyl methacrylate (PMMA), was evaluated in an animal model in which bone formation and resorption are independent of each other. Neither material accelerated resorption, but formation was inhibited 12% by vitallium and 38% by PMMA. When three PMMA preparations varying in monomer content were tested, the data exhibited a dose-response relation, suggesting that inhibition of bone formation was due to the presence of residual monomer.

Animals↗
PubMed1981

Oral Hygiene Skill Achievement Index I.

The oral hygiene Skill Achievement Index (S.A.I.) is a general method for the direct, quantitative evaluation of oral hygiene skill. The S.A.I. evaluates a person's ability to manipulate a toothbrush and floss in a given fashion. It is applicable to any brushing or flossing procedure. The Index was developed to fulfill all the postulated requirements of a perfect measuring instrument. The key feature of the Index is the evaluation of the position and the motion of the cleaning device on each tooth surface. Consequently, the Index provides a format for the instruction and evaluation of oral hygiene skill. Furthermore, if used in conjunction with other dental indices, it enables one evaluate hygiene procedures and devices in a controlled fashion.

Achievement↗
PubMed1981

Oral Hygiene Skill Achievement Index II.

The utility of any index depends on its validity, reliability, and administrative feasibility. The Oral Hygiene Skill Achievement Index (S.A.I.) was found to be a valid measure of oral hygiene skill in that registered dental hygienists received greater than 90% of the total possible points. The S.A.I. was found to have an initial reliability of r greater than or equal to 0.91 and a repeat reliability of r greater than or equal to 0.96. The S.A.I. requires less than 10 minutes to administer, 40 minutes to teach, and 1 hour and 40 minutes to learn. The results suggest that S.A.I. should be a useful instrument for both clinical and research use.

Achievement↗
PubMed1979

The appearances of common dental diseases on radionuclide bone images of the jaws.

Radionuclide images of hospital patients were examined for abnormal areas within the jaws. Fourteen of 25 subjects studied showed one or more abnormal image areas, most of which were attributable to common dental lesions revealed by oral examinations. The lesions detectable on images included healing bone sites, periodontal and pulpal disease, residual osteitis and irritations caused by ill-fitting dentures.

Adult↗
PubMed1978

Bone scan in dental diseases.

Bone images of the jaws and related dental structures were obtained in 25 patients undergoing skeletal surveys. The upper and lower jaws were divided into eight quadrants to facilitate comparisons between scintigraphic image findings and the results of dental examination. Fourteen of these 25 patients had at least one jaw quadrant with a positive image. The areas of positive uptake correlated well with dental examination findings, which included healing extraction sites and common dental diseases, such as pulpal and periodontal infections and irritations from ill-fitting dentures. The potential usefulness of bone imaging as an adjunct in dental diagnosis is discussed.

Adult↗
PubMedDate not supplied

The relationship between paraquat accumulation and covalent binding in rat lung slices.

The accumulation and covalent binding of paraquat in rat lung slices were both linear for 6 hr in room air incubations. Binding continued to increase in slices transferred to paraquat-free buffer after 3 hr of incubation in paraquat although accumulated paraquat decreased. Binding in 100% O2 was decreased slightly. Active accumulation in 100% N2 did not occur, but binding proceeded at one-third the rate observed in room air. Ascorbate decreased accumulation in room air, although binding was unaffected. Reductants had no effect on binding in 100% nitrogen. Paraquat binding in slices of various organs was in the order of lung greater than liver greater than heart greater than kidney cortex. Mitochondrial proteins were found to have the highest concentration of bound paraquat in lung slices followed in order by microsomal protein greater than nuclear protein = cytosolic protein. The binding of paraquat is postulated to involve a reduced species, presumably the monovalent radical.

Animals↗