Biomedical subjects

Michael Exton

Publications and source records attributed to Michael Exton.

3 recordsLinked to original sources

PubMed2004

Dopexamine and cellular immune functions during systemic inflammation.

An immune-neuroendocrine interaction that is mediated via beta2-adrenergic receptors has been demonstrated previously. Dopexamine is a substance with strong beta2-adrenergic effects and is used in the treatment of critically ill patients. We therefore investigated the effect of dopexamine infusion on survival and cellular immune functions during systemic inflammation. Sepsis (CLP) was induced in male NMRI mice that received either 0.9% saline, dopexamine (0.05 mg/kg/hour ip, DPX), the selective beta2-adrenergic antagonist ICI 118.551 (0.5 mg/kg ip every 12 hours, ICI) or a combination of both drugs. 48 hours after onset of sepsis, survival rate, splenocyte apoptosis, splenocyte proliferation, splenocyte IL-2, IL-6 and IFN-gamma release, and leukocyte distribution were monitored. Dopexamine increased splenocyte apoptosis and normalized the distribution of circulating lymphocytes but did not affect sepsis-induced mortality. ICI 118.551 induced a dramatic increase of mortality paralleled by a decreased splenocyte proliferation and the strongest increase in splenocyte apoptosis. Co-administration of dopexamine abolished the ICI 118.551-induced alterations but this effect seemed to be mediated via a pathway other than adrenergic beta2-receptors. We conclude that dopexamine modulates cellular immune functions during systemic inflammation and that different receptor systems are involved in the mediation of this process. Furthermore, the immunomodulatory effect of beta2-adrenergic blockade was demonstrated.

Adrenergic beta-Antagonists↗

PubMed2004

Alzheimer patients treated with an AchE inhibitor show higher IL-4 and lower IL-1 beta levels and expression in peripheral blood mononuclear cells.

The study evaluates the expression and production of cytokines in peripheral blood mononuclear cells of patients with Alzheimer disease treated or not treated with acetylcholinesterase inhibitor, which enhances neuronal transmission. Cytokines associated with brain inflammation such as interleukin (IL)-1beta, IL-6, and tumor necrosis factor-alpha have been implicated in the regulation of amyloid peptide protein synthesis. The anti-inflammatory cytokine, IL-4, may suppress the activity of IL-1beta. Patients were assessed for clinical and immunologic features at baseline and after 1 month of treatment with Donepezil, an acetylcholinesterase inhibitor. Peripheral blood mononuclear cells were cultured with and without phytohemagglutinin stimulation. IL-1beta and IL-4 levels were measured by enzyme-linked immunosorbent assay. Reverse transcriptase-polymerase chain reaction was used to determine the expression of cytokines in peripheral mononuclear cells. Compared with untreated patients and healthy control subjects, IL-1beta levels and expression decreased in Alzheimer disease patients treated with Donepezil (P < 0.001). In contrast, IL-4 levels and expression were significantly higher in Alzheimer patients treated with the acetylcholinesterase inhibitor. This increment was observed in both unstimulated and phytohemagglutinin-stimulated peripheral blood mononuclear cells.

Aged↗

PubMed2002

Concomitant endocrine and immune alterations during alcohol intoxication and acute withdrawal in alcohol-dependent subjects.

Although both alcohol intoxication and withdrawal have been demonstrated to produce significant endocrine alterations, no data exist on the effects of acute withdrawal on immune functions. Therefore, the current study investigated the effect of alcohol intoxication and acute withdrawal on plasma cortisol, prolactin and catecholamines, and blood leukocyte subset distribution in alcohol-dependent subjects. Nine male alcoholics admitted to the university clinic for alcohol dependence and 9 age-matched controls participated in the study. Blood was drawn from the alcohol-dependent subjects at 10:30 a.m. on day 0 (chronic alcohol intoxication), at the same time during acute alcohol withdrawal (day 1) and following the resolution of acute withdrawal (day 7). Blood was drawn from age- and gender-matched healthy control subjects at the corresponding time points. Plasma was then analyzed for hormone concentrations and blood examined for leukocyte subsets by flow cytometry. Alcohol-dependent patients displayed significantly elevated plasma cortisol during intoxication and withdrawal, which decreased to control levels following resolution of acute withdrawal. Small elevations of plasma prolactin and catecholamines were also observed during intoxication. Furthermore, alcohol-dependent subjects showed reduced absolute numbers of CD4(+) and CD8(+) T cells and natural killer cells compared with healthy controls across all time points. In contrast, although monocyte numbers were lower in alcohol-dependent patients during intoxication, acute alcohol withdrawal increased the number of monocytes in patients. Thus, alcohol dependence produces a general suppression of leukocyte subset populations in blood. However, resolution of acute alcohol withdrawal is associated with a return of plasma cortisol to control levels, and a concomitant increase in peripheral blood monocyte numbers.

Alcoholic Intoxication↗