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T Newton

Publications and source records attributed to T Newton.

At least 19 recordsLinked to original sources
PubMed1998

Cocaine infusion increases interferon-gamma and decreases interleukin-10 in cocaine-dependent subjects.

The effects of cocaine infusion (40 mg) on interferon-gamma (IFN-gamma) and interleukin-10 (IL-10) cytokine secretion were examined in 15 cocaine-dependent subjects. Pre- and postcocaine infusion peripheral blood mononuclear cells (PBMC), stimulated with phytohemagglutinin A, were cultured for 48 h and the cytokines in the supernatant measured by enzyme-linked immunosorbent assay. Cocaine infusion, but not saline infusion, increased IFN-gamma secretion and decreased IL-10 secretion, while, in PBMC collected simultaneously from control subjects, secretion of these cytokines was unaltered. Baseline IFN-gamma levels were lower and IL-10 levels higher in addicted subjects compared to those in control subjects. White blood cell and lymphocyte number and CD4(+) and CD8(+) counts were all increased following cocaine infusion. In vitro cocaine treatment of PBMC from addicted subjects suppressed both IL-10 and IFN-gamma secretion. These data suggest that acute cocaine administration, via both central and peripheral effects, may enhance Th1-type immune responses and inhibit Th2-type responses.

Adult↗
PubMed1998

Cocaine enhances monocyte migration across the blood-brain barrier. Cocaine's connection to AIDS dementia and vasculitis?

Cocaine has wide-ranging effects on the immune and neuroendocrine systems (Fiala et al., 1996) resembling an inflammatory "stress" response with upregulation of pro-inflammatory cytokines and stimulation of the HPA axis (Gan et al., 1997). Cocaine abuse has also been associated with vascular pathology, including vasculitis, vasospasm and hemorrhage. These effects suggest that cocaine could perturb the function of endothelial cells, including the blood-brain barrier, and influence the progression to AIDS in HIV-infected individuals (Shapshak et al., 1997; Goodkin et al., 1997). In order to understand clinical consequences of cocaine abuse, it is important to gain insight into molecular and cellular basis of cocaine's effects on immune and endothelial cells. Cocaine's in vitro effects on (a) permeability, (b) immune cell migration, (c) adhesion molecules, and (d) cytokine expression were investigated in a blood-brain barrier model constructed with brain microvascular endothelial cells and fetal astrocytes with the following results: (a) cocaine and tumor necrosis factor-alpha (TNF-alpha) increased the model's permeability to inulin similarly in a dose-responsive fashion; (b) cocaine (10(-4) to 10(-8_ M) enhanced monocyte migration across the barrier with the maximum increase, approximately 100%, by 10(-5) M cocaine; (c) cocaine treatment also increased the expression of endothelial adhesion molecules, intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecules-1 (VCAM-1) and platelet/endothelial cell adhesion molecule-1 (PECAM-1); (d) although the cocaine in vitro effects on cytokine production by mononuclear cells have been difficult to assess due to a heterogeneity in the degree of responsiveness between individuals, the data suggest that mononuclear cells from cocaine addicts are sensitized to in vitro cocaine challenge with hypersecretion of inflammatory cytokines. Cocaine's in vivo manifestations are compatible with these in vitro effects: (A) chronic cocaine treatment of rats significantly increased rolling white blood cell flux, leukocyte-endothelium adhesion, and ICAM-1 expression in the mesentery (House et al., 1996); (B) cocaine injection to cocaine-dependent subjects tipped the balance of cytokine secretion by mononuclear cells to Th1-type (Gan et al., 1997), and (C) cocaine injection stimulated the hypothalamic-pituitary axis (HPA) to increase both anti- and pro-inflammatory hormonal secretion. Collectively, these results suggest that the immune effects of cocaine on endothelial, immune and neuroendocrine cells impair the function of the blood-brain, barrier, increase cell emigration from the blood vessels, in particular into the brain, and may cause vasculitis. These effects could also increase importation of HIV-1 into the brain.

AIDS Dementia Complex↗
PubMed1996

Amiloride inhibits meal-stimulated colonic absorption.

Meal-stimulated colonic absorption has recently been described, but the cellular transport mechanisms mediating this response are unknown. The purpose of this study was to determine the contribution of Na+ transport pathways to colonic proabsorption. Distal colonic Thiry-Vella loops were constructed in six dogs. Absorption was measured by infusing the loops with a physiological electrolyte solution containing [14C] polyethylene glycol as the impermeant marker. In the first set of experiments, the dose dependence of amiloride-induced inhibition of basal colonic absorption was determined. In the second set of experiments the effect of amiloride, which inhibits both Na+ channels and Na+/H+ exchange in colonocytes, on meal-stimulated colonic absorption was determined. Luminal amiloride inhibited basal colonic absorption in a dose-dependent manner, with significant reductions in Na+ absorption occurring with concentrations of 10(-2)M and higher. Infusion with 10(-3)M amiloride, a concentration that did not alter basal absorption, resulted in significant reductions in postprandial water, Na+, and Cl- absorption. These results suggest that meal-stimulated colonic absorption is mediated, at last in part, by transcellular Na+ absorptive pathways.

Amiloride↗
PubMed1996

Glucose polymer as a cause of protracted diarrhea in infants with unsuspected congenital sucrase-isomaltase deficiency.

OBJECTIVE: To describe four infants with protracted diarrhea caused by glucose polymer intolerance resulting from congenital sucrase-isomaltase deficiency. METHODS: The diagnosis of congenital sucrase-isomaltase deficiency was established by mucosal disaccharidase assay. In each case the clinical response to discontinuation of glucose polymer was documented. RESULTS: The median age at the onset of symptoms was 3 weeks (range, 2 to 16 weeks). In three infants the formula had been prescribed for presumed postgastroenteritis diarrhea, and in a fourth it was begun after resection of a short-segment congenital ileal atresia. In each infant watery diarrhea occurred and persisted for many months, and it was assumed that the original gastrointestinal disorder was responsible. In two cases, parenteral nutrition was administered for persistent failure to thrive. Ultimately, investigation revealed the underlying congenital sucrase-isomaltase deficiency, and elimination of glucose polymer from the diet led to immediate recovery in each case. CONCLUSION: Congenital sucrase-isomaltase deficiency should be considered a possible cause of protracted diarrhea in infants receiving glucose polymer-based feedings.

Carbohydrate Metabolism, Inborn Errors↗
PubMed1996

Marital conflict and endocrine function: are men really more physiologically affected than women?

This study assessed marital conflict behavior and endocrine function in 90 newlywed couples. Blood samples acquired hourly from 8:00 a.m. through 10:00 p.m. were combined to provide composite daytime values for 3 stress hormones -- epinephrine (EPI), norepinephrine (NEPI), and cortisol -- and 3 related hormones (ACTH, growth hormone, and prolactin). These pooled data provided a window on endocrine function in couples for whom the day included a conflict. For wives, higher probabilities of husband's withdrawal in response to wife's negative behavior were associated with higher NEPI and cortisol levels. In addition, higher frequencies of positive behaviors were associated with lower EPI and higher prolactin levels among wives. Husbands' endocrine data were not associated with behavioral data. These findings are discussed in the context of gender models of marital conflict.

Adrenocorticotropic Hormone↗
PubMed1995

HIV and dentistry: public perceptions from two towns in Kent.

A survey of general public attitudes towards dentists who are HIV-positive or who have AIDS was carried out on two occasions three months apart, in the Kentish towns of Dartford and Tunbridge Wells. The BBC television programme, Panorama discussing this issue was screened between the two survey times. The results show that in general the public in these areas perceive the risk of acquiring HIV infection through dental treatment to be very low: despite this they do not have a great knowledge of cross-infection control procedures in the dental setting.

Acquired Immunodeficiency Syndrome↗
PubMed1992

Public perceptions of the funding of NHS dental services.

A survey was carried out of 102 members of the general public, asking for their views of the recent changes in the government funding of NHS dentistry. Approximately 80% of those surveyed had heard about the changes. The majority thought that the implications of the change would be a rise in costs to patients and a fall in the number of NHS dentists.

Adolescent↗
PubMed1991

An experimental analysis of perfectionism and dissatisfaction.

The striving after perfection has been often mentioned in clinical literature; however, there have been few systematic analyses of the concept. In the present study, a questionnaire measure of Perfectionism and General Dissatisfaction (the SCANS) together with the Eysenck Personality Questionnaire and measures thought to gauge aspects of perfectionistic thinking, were administered to a mixed group of 148 subjects, including 25 eating disorder patients. Perfectionism was found to correlate negatively with Psychoticism (as measured by the EPQ) and positively with the Lie scale. Thus Perfectionism appears to be associated with a tendency to deny personally deviant behaviour and to present oneself in the best possible light. It is also associated with greater accuracy in a visual search task. General Dissatisfaction was correlated significantly with Neuroticism, Introversion and Psychoticism. It thus appears to be related to a combination of 'neurotic introversion' and 'personality deviance'. It is also associated with a tendency to be under-inclusive, that is to find difficulty in ruling out irrelevant stimuli when forming categories. Dissatisfaction was also associated with increased reaction time in the visual search task, perhaps also a reflection of an inability to ignore irrelevant stimuli. Only the EPQ N and P scales successfully differentiated neurotic or dissatisfied perfectionists from normal or satisfied perfectionists, although several measures derived from the visual search task produced results which were approaching significance.

Adult↗
PubMed1988

Writing behavioural objectives: an evaluation of a simple, inexpensive method.

This study demonstrated experimental control of nurse compliance with writing behavioural objectives in a National Health Service adult training unit for mentally handicapped adults. At the baseline, low rates of compliance in writing complete behavioural objectives (i.e. an objective referring to a resident, an action, a prompt and a target) were identified. A simple environmental manipulation, namely redesigning the activity charts, led to an increase in writing complete behavioural objectives. Experimental control was demonstrated using a multiple baseline design across two groups of staff. Nurse compliance with writing adequate prompts and targets was less than compliance with writing names and behaviours. Greater degrees of compliance may require alternative methods of staff management such as feedback procedures.

Behavior Therapy↗
PubMed1988

Psychometric properties of the Pain Assessment Questionnaire.

The Pain Assessment Questionnaire (PAQ) was administered to 58 health care professionals with a concurrent validation measure, the Knowledge of Behavioral Principles Questionnaire. The PAQ showed adequate internal consistency, concurrent and criterion group validities. Attempts to develop two parallel forms of the PAQ and replicate the factor structure reported by Saunders & Webster (1982) were unsuccessful.

Adult↗
PubMed1987

Parallel forms of the Knowledge of Behavioral Principles as Applied to Children questionnaire: an independent, multi-centred, British replication.

The psychometric properties of the test entitled Knowledge of Behavioral Principles as Applied to Children and two shortened forms of this test were investigated in two samples of British subjects. The first consisted of 162 psychiatric nurses, psychiatrists, occupational therapists, physiotherapists and clinical psychologists attending behaviour modification courses. The second consisted of 49 teachers and nurses, all working with the mentally retarded, who completed the test by post. The whole test and the two sets of parallel forms all showed good internal consistency and sensitivity to change. Some shrinkage during replication was found. The 25-item forms showed evidence of the properties of parallel forms (equal means, standard deviations and standard errors) in both samples. The 10-item forms were also parallel in sample 1. However the 10-item forms did not remain parallel in sample 2 and so cannot always be recommended.

Behavior Therapy↗
PubMed1985

The puzzle of drug-induced conditioned taste aversion: comparative studies with cathinone and amphetamine.

The potency of dl-cathinone (the active constituent of the Khat plant) was compared with that of d-amphetamine in the conditioned taste aversion (C.T.A.) procedure and in a test of drug-induced adipsia in rats. Both drugs induced C.T.A., the potency ratio being 1:17 (amphetamine was more potent). Both drugs induced adipsia in deprived rats given access to water for 120 min. The potency ratio in this procedure was 1:4. Potency in the C.T.A. procedure did not therefore correlate with potency in inducing adipsia; consequently drug-induced C.T.A. cannot be attributed to conditioned adipsia. In the adipsia test the drugs had similar durations of action, thus factors related to duration of drug action (cf Cappell and Le Blanc 1977) cannot account for the surprisingly low potency of cathinone in the C.T.A. procedure. These data, obtained with stimulant drugs with similar structures and similar actions in a variety of conventional in vivo and in vitro pharmacological tests, illustrate the unpredictable nature of drug actions in the C.T.A. procedure. The low potency of cathinone in inducing C.T.A. could not be predicted from knowledge of the potency of this compound in tests of adipsia (as shown here) or (as reported elsewhere) in tests of anorexia, locomotor stimulation, stereotypy, suppression of operant responding, drug discrimination, release and inhibition of reuptake of dopamine and noradrenaline, lethality and actions on the cardiovascular system. All of these studies have reported potency ratios considerably lower than 1:17, which were nevertheless similar to the 1:4 ratio observed in the adipsia test.(ABSTRACT TRUNCATED AT 250 WORDS)

Alkaloids↗
PubMedDate not supplied

Negative behavior during marital conflict is associated with immunological down-regulation.

Although increased morbidity and mortality have been reliably associated with social isolation and less satisfying personal relationships, relatively little is known about the underlying biopsychosocial mechanisms. We assessed problem-solving behaviors and changes in immune function in 90 newlywed couples who were admitted to a hospital research unit for 24 hours. Subjects who exhibited more negative or hostile behaviors during a 30-minute discussion of marital problems showed greater decrements over 24 hours relative to low negative subjects on four functional immunological assays (natural killer cell lysis, blastogenic response to two mitogens, and the proliferative response to a monoclonal antibody to the T3 receptor), as well as larger increases in the numbers of total T lymphocytes and helper T lymphocytes. High negative subjects had higher antibody titers to latent Epstein-Barr virus than low negative subjects, consistent with down-regulated immune function. Women were more likely to show negative immunological changes than men. The discussion of marital problems also led to larger increases in blood pressure that remained elevated longer in high negative subjects than low negative subjects. Positive or supportive problem-solving behaviors were not related to either immunological or blood pressure changes. These physiological differences were particularly noteworthy because marital satisfaction was high in both groups, and couples had been selected on the basis of stringent mental and physical health criteria. These data provide additional support for the link between personal relationships and immune function.

Adult↗