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Biomedical subjects

S Sullivan

Publications and source records attributed to S Sullivan.

At least 91 records · Page 5Linked to original sources

Conditioned meal initiation in young children.

In two experiments the conditioning of meal initiation was investigated. Preschool children ate snacks repeatedly in the presence of visual and auditory cues (CS+). On other days, other visual and auditory cues (CS-) were presented in the absence of food. In the second experiment, location also served as a CS. To test for conditioned meal initiation, children were first fed a snack to ensure that they were sated. Immediately following this, on different days, food was presented in the presence of the CS+ or the CS- cues. Data on latency to eating and total consumption revealed evidence for conditioning, at least for children who could correctly identify which cues had and had not been paired with the presentation of food.

Child Behavior↗

Gastrointestinal gas.

Complaints related to gastrointestinal gas are commonly encountered in clinical practice. Various therapies have been proposed, yet none has appeared to be extremely effective. A review of the literature revealed little hard evidence to support the use of simethicone, pancreatic enzymes, anticholinergic agents or antibiotics. Evidence supporting the use of prokinetic agents has been the strongest, and there may be a pathophysiologic basis for the use of these agents if the complaints are related to abnormal intestinal motility. The use of activated charcoal for adsorbing intestinal gas has been effective in healthy subjects but has not been properly investigated in patients with gas complaints. Dietary modification may be beneficial in certain cases. Additional controlled trials are necessary to clarify the issues in the treatment of this common problem.

Diet↗

The effect of four narcotics on cholecystokinin octapeptide stimulated gallbladder contraction.

In an attempt to find the ideal analgesic to treat biliary tract pain we compared the effects of saline and equianalgesic doses of morphine, pentazocine, pethidine, and butorphanol on CCK-OP stimulated gallbladder emptying in healthy volunteers. Morphine produced a profound delay in gallbladder emptying while the other narcotics produced a significant delay in comparison to saline, but less than morphine. None of the drugs affected common bile duct diameter, bilirubin, liver enzymes or amylase. We recommend avoiding the use of morphine in the treatment of biliary and pancreatic pain, but although pethidine, pentazocine and butorphanol may be potentially detrimental we could find no definite superiority of one versus the others.

Adolescent↗

Tools to measure sensory appeal of menus planned for children.

The Menu Variety Checklist and Score Sheet is a tool to facilitate evaluation of sensory appeal. Comparisons made across evaluators and across menus show it to be more reliable and more readily diagnostic than subjective summary ratings. Although further research and development are needed to make it more precise and test its criterion validity, the checklist has sufficient advantages to make it a useful starting place or backup tool in research and clinical applications.

Child↗

Polymorphic DNA haplotypes at the human phenylalanine hydroxylase locus and their relationship with phenylketonuria.

Eight polymorphic restriction enzyme sites at the phenylalanine hydroxylase (PAH) locus were analyzed from the parental chromosomes in 33 Danish nuclear families with at least one phenylketonuric (PKU) child. Determination of haplotypes of 66 normal chromosomes and 66 chromosomes bearing mutant allele(s) demonstrated that there are at least two haplotypes which occur predominantly on PKU chromosomes and rarely otherwise. Overall, the relative frequencies of the various haplotypes are significantly different on PKU- and normal-allele bearing chromosomes, even though there is no predominantly occurring unique haplotype which can characterize the PKU chromosomes. In addition, no significant association (linkage disequilibrium) between any single polymorphic site and the mutant allele(s) was observed. The results suggest that either the phenylketonuric mutation was very ancient so that the polymorphic sites and the mutation have reached linkage equilibrium or the mutant allele(s) are the results of multiple mutations in the phenylalanine hydroxylase gene in man. Furthermore, a crude relationship between standardized linkage disequilibria and physical map distances of the polymorphic sites indicates that there is no apparent recombination hot-spot in the human phenylalanine hydroxylase gene, since the recombination rate within the locus appears to be uniform and likely to be occurring at a rate similar to that within the HLA gene cluster. The limitations of this later analysis are discussed in view of the sampling errors of disequilibrium measure used, and the potential utility of the PAH haplotypes for prenatal diagnosis and detection of PKU carriers is established.

Alleles↗

Induction and regulation of contact hypersensitivity by resident, bone marrow-derived, dendritic epidermal cells: Langerhans cells and Thy-1+ epidermal cells.

Circumstantial evidence suggests strongly that epidermal Langerhans cells (LC) alone among epidermal cells (EC) are responsible for generating an immunogenic signal for contact hypersensitivity (CH) after epicutaneous application of hapten. However, data obtained from previous studies performed with intact skin or isolated EC do not address the immunogenic capacity of a second dendritic, bone marrow-derived population of cells that resides within the epidermis, Thy-1+ epidermal cells. To identify the cellular source(s) of the antigenic signals emerging from the epidermis, purified preparations of LC, Thy-1+ cells, and keratinocytes were prepared from CBA/J mouse skin. Each cell type was derivatized in vitro with TNBS and inoculated via various routes into syngeneic mice that were assayed for the induction of CH and specific unresponsiveness. IA+ LC, when derivatized with hapten and inoculated into mice, induced CH without evidence of down-regulation regardless of the route of immunization. Derivatized Thy-1+ EC did not deliver a positive signal for CH. Rather, Thy-1+ EC possessed the capacity to initiate down-regulation of the CH response when they were delivered i.v. We conclude that all cellular elements necessary for the induction and regulation of CH after epicutaneous application of hapten to skin reside within the epidermis. The resident, dendritic, bone marrow-derived populations within the epidermis have the capacity to determine the outcome of an epicutaneous antigenic encounter.

Animals↗

Insulin-mediated and non-insulin-mediated metabolic effects of gastroenteropancreatic peptides in type I and type II diabetes.

In this brief review of regulatory function of gastroenteropancreatic peptides in control of intermediary metabolism in normal and diabetic states, with and without mediation by insulin and/or glucagon, a variety of possible mechanisms have been described. It is apparent that the pharmacologic actions of the peptides identified in various locations provide models for multiple routes of delivery and modes of action of effectors in this control system. Examples already exist of each of the hypothetical mechanisms illustrated in the scheme in Figure 4. It is clear that a great deal of study will be necessary in identification of the active agents and assessment of their importance in the physiology of intermediary metabolism. With respect to the possible pathophysiologic roles of regulatory peptides of the gastroenteropancreatic system other than insulin and glucagon, a number of considerations of Type I and Type II diabetes have been raised. The balance of the evidence suggests that Type I diabetes may be viewed as an insulin deficiency syndrome, so that physiological replacement with insulin may be expected to result in correction of the metabolic abnormalities. Nevertheless, the difficulty of physiologic replacement treatment, which may call for portal delivery of insulin, is well recognized, and abnormalities secondary to insulin deficiency even in "well-treated" Type I diabetes may be compounded by the effects of gastroenteropancreatic peptides other than insulin, exerted through the various mechanisms discussed. In Type II diabetes mellitus, current understanding of the pathophysiology is much less complete and no convincing description of the etiology exists. The various metabolic actions of the gastroenteropancreatic peptides, and their interactions with other endocrine, paracrine and nervous regulatory mechanisms, represent a dauntingly complex control system. The elucidation of this system can provide fertile ground for the development and testing of hypotheses for the pathophysiology of disordered metabolism in Type II diabetes mellitus.

Blood Glucose↗

Effects of calcium binding and of EDTA and CaEDTA on the clotting of bovine fibrinogen by thrombin.

Studies were carried out at pH 7.0 and gamma/2 0.15 before addition of CaCl2 or EDTA. Clotting time, tau, at 3.03 microM fibrinogen and 0.91 u/ml thrombin was determined for equilibrium systems. With added Ca2+, tau decreases, from tau 0 at 0 added Ca2+ (mean, 29.7 +/- 3 s), by approximately 3 s at 5 mM added Ca2+. With added EDTA, tau increases sigmoidally from tau 0 at 0 EDTA to a maximum (mean tau m = 142 +/- 23 s) at approximately 200 microM EDTA. tau then decreases slightly to a minimum at approximately 1.3 mM and finally increases to infinity at approximately 10 mM EDTA. Between 0 and 1.3 mM EDTA, effects on clotting time are completely reversed by adding Ca2+ and, after equilibration at 400 microM EDTA, tau is independent of EDTA concentration. Thus, up to 400 microM EDTA, effects on clotting time are attributed to decreasing fibrinogen bound Ca2+. Between 5 mM Ca2+ and 200 microM EDTA it is assumed that an equilibrium distribution of fibrinogen species having 3, 2, 1, or 0 bound calcium ions is established and that a clotting time is determined by the sum of products of species fractional abundance and pure species clotting time. Analysis indicates that pure species clotting times increase proportionately with decreasing Ca2+ binding, binding sites are nearly independent, and the microscopic association constant for the first bound Ca2+ is approximately 4.9 X 10(6) M-1. Effects of adding Ca2+ at times t1 after thrombin addition to systems initially equilibrated at 200 microM EDTA were determined. Analysis of the relation between tau and t1 indicates that as Ca2+ binding decreases, rate constants for release of B peptides decrease less than those for release of A peptides. As EDTA concentration is increased above 1.3 mM, inhibitory effects of EDTA and CaEDTA progressively increase.

Animals↗

Management of adenocarcinoma in a columnar-lined esophagus.

Of 89 patients diagnosed between 1973 and 1983 as having at least 3 cm of columnar-lined esophagus, 22 were found to have adenocarcinoma. There was no difference in sex ratio, smoking, or the use of alcohol between the benign and adenocarcinoma groups. The patients with adenocarcinoma were older (63 years versus 57 years) and had a higher frequency of dysphagia (64% versus 46%), gastrointestinal bleeding (36% versus 24%), extended columnar-lined esophagus (94% versus 28%), and epithelial dysplasia (68% versus 10%). Heartburn was less frequent in the adenocarcinoma group (59% versus 79%), but when it occurred, it was of longer duration (mean, 18.8 years versus 10.9 years). In 2 patients, progression from benign columnar-lined esophagus to early adenocarcinoma was observed. Of the patients with adenocarcinoma, 2 received palliative treatment without resection and died four and nine months later. Six underwent partial esophagogastrectomy with 1 postoperative death. Four had residual columnar-lined esophagus at the resection margins. In one of them, stricture developed and in one, anastomotic recurrence of adenocarcinoma; 1-year survival was 50%. Fourteen patients underwent total thoracic esophagectomy with no operative deaths, strictures, or anastomotic recurrences; 1-year survival was 5 of 6. Surgical staging revealed that 63% had transmural spread and 55%, lymph node involvement.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenocarcinoma↗

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↗

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↗

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↗