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Biomedical subjects

S Sullivan

Publications and source records attributed to S Sullivan.

At least 109 records · Page 6Linked to original sources
PubMed1985

A work-site weight control program using financial incentives collected through payroll deduction.

In a work-site weight control program using a self-motivational program of financial incentives implemented through payroll deduction, 131 university employees chose weight loss goals (0 to 60 lb) and incentives (+5 to +30) to be deducted from each paycheck for six months. Return of incentive money was contingent on progress toward weight goals. Participants were assigned randomly to one of four protocols, involving group educational sessions v self-instruction only and required v optional attendance at weigh-ins and sessions. Overall, dropout rates (21.4%) and mean weight loss (12.2 lb) were encouraging, especially compared with those of other work-site programs. Weight loss was positively associated with attendance at weigh-ins and educational sessions. However, requiring attendance did not increase program effectiveness and seemed also to discourage enrollment among men. The weight control program was equally effective when offered with professionally led educational sessions or when accompanied by self-instructional materials only.

Adult↗
PubMed1985

Intravenously injected, TNP-derivatized, Langerhans cell-enriched epidermal cells induce contact hypersensitivity in Syrian hamsters.

The ability of haptenated subpopulations of epidermal cells (EC) to induce contact hypersensitivity (CH) in Syrian hamsters was investigated. Crude haptenated EC and haptenated EC enriched for Langerhans cells (LC) inoculated i.v. into hamsters induced CH that was equivalent in intensity to that induced by epicutaneous application of hapten. By contrast, haptenated EC, relatively depleted of LC, failed to induce CH hypersensitivity responses. Upon subsequent reimmunization of all animals with epicutaneously applied hapten, hamsters that had first received haptenated EC depleted of LC failed to respond in CH assays, indicating that these animals had been rendered unresponsive. These data suggest that haptenated LC are capable of inducing CH regardless of the route of inoculation, whereas haptenated EC, when depleted of LC, deliver a down-regulating signal via the i.v. route.

Animals↗
PubMed1985

FACS purification of bone marrow-derived epidermal populations in mice: Langerhans cells and Thy-1+ dendritic cells.

A method was developed which allows for the separation and purification of Langerhans cells (LC) and Thy-1+ cells (Thy-1+dEC) from mouse epidermis. Epidermal cell (EC) suspensions were subjected to Ficoll separation, and the resulting interface EC were harvested. These EC were then "tagged" with the appropriate monoclonal antibody and sorted into positive and negative populations using the Fluorescence Activated Cell Sorter (FACS). Preparations of viable LC and Thy-1+dEC were obtained with 94-98% and 94-99% purities, respectively.

Animals↗
PubMed1985

Origin and function of Thy-1+ dendritic epidermal cells in mice.

The epidermis of normal mouse skin incorporates a newly-recognized population of dendritic cells which express relatively large amounts of the cell surface glycoprotein, Thy-1 antigen. These cells, termed Thy-1+dEC, are distinct from both epidermal Langerhans cells (LC) and melanocytes, and they populate cutaneous sites in surface densities which range to as high as 580 cells/mm2, approximately two-thirds that of LC. Studies of lethally irradiated mice which were reconstituted with semiallogeneic bone marrow cells and mice which received grafts of semiallogeneic skin have demonstrated that some, if not all, Thy-1+dEC are of bone marrow origin, and that they are capable of migrating into epidermis from a vascular source. Thy-1+dEC expressed both asialo GM1 and a cell surface determinant recognized by the monoclonal antibody 20-10-5S, further suggesting their functions will be included among those normally ascribed to lymphoreticular cells. Isolation of epidermal cells with the Fluorescence Activated Cell Sorter (FACS) was successful in producing relatively pure populations of Thy-1+dEC and LC. Such technological advances as this should facilitate testing several hypotheses concerning the ultimate function of these cells, including the possibilities that they are antigen-presenting cells which selectively activate down-regulating signals, T lymphocytes, natural killer (NK) cells, or natural suppressor (NS) cells.

Animals↗
PubMed1985

Pathogenesis of hepatic fibrosis in experimental iron overload.

Significant increases in prolyl hydroxylase activity, a key enzyme in the collagen biosynthetic pathway, were noted in the hepatic homogenates of iron-loaded animals as compared to controls. The increase in prolyl hydroxylase activity was seen without any light microscopic histologic evidence of cell necrosis or accumulation of collagen in the livers from the iron-loaded animals. However, utilizing electron microscopy, collagen fibrils were demonstrated immediately adjacent to the hepatocytes in the iron-loaded animals but not the controls. No fibroblasts or inflammatory cells were noted in this area. There was no evidence of damage to the subcellular organelles of the iron-loaded hepatocytes. The hydroxyproline content of the iron-loaded livers was also shown to be increased. These experimental studies in conjunction with clinical observations described below suggest that in vivo iron overload may have a primary effect on stimulating collagen synthesis by hepatocytes.

Animals↗
PubMed1983

Ophthalmic psychoneurosis: natural history.

The status of 18 patients presenting with ocular psychosomatic symptoms is reviewed 10 to 18 months after presentation. All the patients had been discharged after the examination and reassurance given at the initial interview. In 8 patients symptoms had completely ceased, but 10 patients retained their symptoms. Transitory, self-limiting symptoms were more commonly associated with anxiety and occurred in the younger patients. Persistent symptoms were more commonly associated with depression and occurred in the older patients. Pain of the eyes, face, and head is conspicuous in both groups.

Adolescent↗
PubMed1983

A study of gastrointestinal opiate receptors: the role of the Mu receptor on gastric emptying: concise communication.

Animal and in vitro experiments suggest that opiates exert their actions by interaction with possibly five different subtypes of opiate receptors, identified as mu, kappa, sigma, delta, and epsilon. As yet there is no conclusive evidence for their existence in man. Our experiments on morphine and the enkephalin analog DAMME have suggested at least two types of opiate receptors involved in gastric secretion. In this study we have used the very powerful and nonselective opiate agonist etorphine to stimulate as many of the different opiate receptors as possible. We have then attempted to block selectively the mu receptor by administering a small dose of naloxone. Etorphine delayed gastric emptying whereas naloxone alone had no effect. In combination, the inhibitory effect of etorphine on gastric emptying was incompletely prevented while the subjective effects of etorphine were completely abolished. These results may indicate that mu receptors are important in the regulation of gastric emptying, but that other (non-mu) receptors are also involved. The radionuclide study of gastric emptying, as used here, is a potentially powerful tool in physiological research on the gastrointestinal tract.

Adult↗
PubMed1983

Validation and application of nutrition education objectives.

Nutrition education is more likely to be effective when nutrition and education professionals set goals in working with individuals. In an effort to assist such professionals with these goals, 24 objectives for nutrition education were identified and validated. Teachers, dietitians, and nutritionists can use these objectives in analyzing and targeting their nutrition efforts to influence behavior change in students, patients, employees, and clients. Ways to use the objectives and a process for behavior change to use with students are suggested.

Curriculum↗
PubMed1982

Opioid peptides as neuroregulators: potential areas for the study of genetic-behavioral mechanisms.

The opioid peptides have been related to behavior in both animal and human studies. Further investigation can be anticipated which could lead to the elucidation of genetic controls over enzymes which process these peptides and the receptors upon which the peptides act. The enzymes, both synthetic and degradative, can lead to the formation of different forms of the opiate peptides. Differential control of these enzymes or of the multiple forms of opiate receptors could lead to discrete changes in opiate status and subsequent behavioral changes. Conversely, genetically regulated behavioral modification could also lead secondarily to opiate changes.

Aminopeptidases↗
PubMed1980

Enkephalinase: selective inhibitors and partial characterization.

There are at least two types of enzymes in brain, endopeptidases and aminopeptidases, which metabolize enkephalins. Evidence is presented to suggest that enkephalinase, an endopeptidase cleaving at the Gly-Phe bond, is specific for the endogenous enkephalinergic system. Selective inhibitors are described for each enzyme. These are parachloromercuriphenylsulfonic acid and puromycin in the case of aminopeptidases and various enkephalin fragments in the case of enkephalinase. Some characteristics of the two types of enzymes are described. Enkephalinase has many properties in common with the well-characterized brain angiotensin-converting enzyme. These two enzymes, however, behaved differently when tested for chloride dependence, for activity in several buffers and for susceptibility to specific inhibitors.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1980

Contact hypersensitivity, humoral immunity, and specific unresponsiveness can be induced in Syrian hamsters with simple haptens.

Several inbred strains of Syrian hamsters have been immunized by skin painting with highly reactive haptens. Classical contact hypersensitivity has been assayed by the ear swelling response: the response is hapten-specific, exaggerated after re-immunization with the original hapten, and can be transferred adoptively to naive syngeneic hamsters with viable lymphoid cells, suggesting that contact hypersensitivity is mediated in hamsters by T lymphocytes. Moreover, skin painting with hapten induces significant serum titers of anti-hapten antibodies, indicating that antigen-specific B lymphocytes are also activated. Hamsters can be rendered unresponsive to these same haptens by conventional methods: 1) i.v. inoculation of the soluble hapten sulfonate or 2) inoculation of hapten-derivatized syngeneic lymphoid cells. Hamsters treated with these "tolerizing" maneuvers develop profound hapten-specific unresponsiveness that can be adoptively transferred to naive recipients with living lymphoid cells. "Unresponsive" animals, however, make strong anti-hapten antibody responses that rival the humoral immune responses found after skin sensitization. The data suggest that an active process is involved in the induction and maintenance of the unresponsive state, but responsibility can not be assigned firmly to putative suppressor T cells or to an antibody-mediated B suppressor modality.

Animals↗
PubMed1979

Studies on the frequency and pathogenesis of liver involvement in rheumatoid arthritis.

A systematic prospective survey of 100 outpatients with rheumatoid arthritis revealed that 45 had biochemical evidence of liver disease. In most cases this was due to increases in total serum alkaline phosphatase (ALP) and/or gammaglutamyl transpeptidase (GGT). Examination of serum ALP isoenzyme profiles in 50 of the patients showed that the liver isoenzyme was the sole or major component in 44 patients, including many with normal total ALP levels. 18% had raised serum liver ALP together with raised GGT, suggestive of an underlying hepatobiliary lesion. No correlation could be detected between raised serum levels of liver enzymes and the age or sex of the patient, duration or severity of arthritis, and drug or alcohol history. However, there was a significant correlation between raised serum ALP and lacrimal or salivary gland dysfunction. It is suggested that immunological mechanisms may be involved in the development of hepatic abnormalities in rheumatoid arthritis.

Adult↗
PubMed1979

Diminished contractile response of aortas from diabetic rabbits.

We investigated the responsiveness of isolated diabetic and normal rabbit aortic strips to norepinephrine. Alloxan, 160 mg/kg, was administered intravenously 1 mo before experiments were performed. Helically cut thoracic aortic strips from diabetic and control animals were suspended side by side in the same muscle bath. The maximum contractile response to norepinephrine of diabetic strips was 68 +/- 5% of control in eight pairs of animals (P less than 0.001). This differential response was not changed by propranolol or cocaine, indicating that it is not explained by either enhanced beta receptor activity or more avid uptake of norepinephrine by nerve endings. Tyramine responses displayed the same differential, suggesting that endogenous release of norepinephrine also results in a lower response of diabetic aortic strips. Maximum responses to KCl were also markedly depressed in strips from nine diabetic rabbits (P less than 0.005). This indicates that the diabetes-induced changes occur at a stage in contraction beyond alpha-receptor activation.

Animals↗
PubMed1978

Impairment of lachrymal and salivary secretion and cellular immune responses to salivary antigens in rheumatoid arthritis.

During a systematic investigation of 100 unselected outpatients with rheumatoid arthritis, 58 were found to have reduced lachrymal or salivary secretion. No correlation could be detected between the presence or absence of secretory abnormalities and the age or sex of the patient, the presence of nodules or salivary duct antibody, or the occurrence of vasculitis. However, there was a significant correlation between diminished salivary of lachrymal flow and the occurrence of cellular immune responses to a protein fraction of normal human saliva, sensitisation being found in 94% of those with impairment of salivary and lachrymal secretion as compared with 33% of those without.

Aged↗