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J L Brunet

Publications and source records attributed to J L Brunet.

14 recordsLinked to original sources
PubMed2002

[Role of pathological delayed-type hypersensitivity in chronic fatigue syndrome: importance of the evaluation of lymphocyte activation by flow cytometry and the measurement of urinary neopterin].

Chronic fatigue syndrome or benign myalgic encephalomyelitis has been extensively described and investigated. Although numerous immunological abnormalities have been linked with the syndrome, none have been found to be specific. This article describes the detection of delayed-type hypersensitive responses to certain common environmental antigens in almost fifty per cent of patients with this syndrome. Such hypersensitivity can be detected by the intradermal administration of antigens derived from commensal organisms like the yeast Candida albicans, and then monitoring for a systemic reaction over the following six to forty eight hours. This approach can be consolidated by performing lymphocyte activation tests in parallel and measuring in vitro T-cell activation by Candida albicans antigens by three-colour flow cytometry based on CD3, CD4 and either CD69 or CD25. Another useful parameter is the kinetics of neopterin excretion in the urine over the course of the skin test. The results showed that the intensity of the DTH response correlated with the number of T-cells activated in vitro. Various factors have been implicated in the fatigue of many patients, notably lack of sleep. However, it remains difficult to establish causality in either one direction or the other. This work is in the spirit of a multifactorial approach to the group of conditions referred to as "chronic fatigue syndrome".

Adolescent↗
PubMed2001

[Diagnosis of normal and abnormal delayed hypersensitivity to Candida albicans. Importance of evaluating lymphocyte activation by flow cytometry].

Delayed type hypersensitivity (DTH) to Candida albicans is commonly observed in human. Abnormal DTH has already been described but its diagnosis is difficult to ascertain. We present now a clinical and biological study in 60 patients with a clear distinction between these two kind of Candida albicans DTH. Clinical abnormal Candida albicans DTH was characterized by a syndromic reaction 24 to 48 hours after intradermal injection. This reaction was characterized by an exacerbation of clinical symptoms. In vitro, activation of whole blood with Candida albicans antigen was detected by using flow cytometry after staining for activating markers. CD 25 positive T cells were detected in a 7 days culture in all patients. Percentage of CD 25 positive T cells was correlated to the intensity of the local cutaneous DTH reaction. CD 69 positive T cells were detected after a one day culture only in patient who presented a syndromic reaction to intradermal injection.

Adolescent↗
PubMed2001

Delayed-type hypersensitivity and chronic fatigue syndrome: the usefulness of assessing T-cell activation by flow cytometry--preliminary study.

Chronic fatigue syndrome or benign myalgic encephalomyelitis has been extensively described and investigated. Although numerous immunological abnormalities have been linked with the syndrome, none have been found to be specific. This article describes the detection of delayed-type hypersensitive responses to certain common environmental antigens in almost fifty per cent of patients with this syndrome. Such hypersensitivity can be detected by the intradermal administration of antigens derived from commensal organisms like the yeast Candida albicans albicans, and then monitoring for a systemic reaction over the following six to forty-eight hours. This approach can be consolidated by performing lymphocyte activation tests in parallel and measuring in vitro T-cell activation by Candida albicans albicans antigens by three-colour flow cytometry based on CD3, CD4 and either CD69 or CD25. Another useful parameter is the kinetics of neopterin excretion in the urine over the course of the skin test. The results showed that the intensity of the DTH response correlated with the number of T-cells activated in vitro. Various factors have been implicated in the fatigue of many patients, notably lack of sleep. However, it remains difficult to establish causality in either one direction or the other. This work is in the spirit of a multifactorial approach to the group of conditions referred to as "chronic fatigue syndrome".

Adolescent↗
PubMed1999

[Evaluation of allergic-type reactions to antibiotics and rapid immunotherapy].

Adverse effects of medications, most notably antimicrobials, are becoming increasingly common and raise difficult challenges in the area of clinical pattern definition (wide variety of symptoms, polypharmacy in many cases), diagnosis, and methodology (need for a rapid diagnosis, frequent obscurity of causative mechanisms, and less than ideal reliability of laboratory techniques). Sixty patients were treated by rush immunotherapy to one or more antimicrobials. The pretreatment evaluation included oriented history taking, skin tests, blood cell counts, IgE assays, and cell activation tests (basophils and lymphocytes). The results of this study confirm the usefulness of skin tests (intradermal, prick, or patch tests), which provided etiological orientation in 54 of the 60 cases. They also provide additional evidence of the lack of reliability of currently available in vitro tests (only 29 of the 60 tests were positive).

Anti-Bacterial Agents↗
PubMed1997

[Diagnosis of delayed type hypersensitivity to Candida albicans. Evaluation of lymphocyte activation by flow cytometry (171 observations)].

Abnormal delayed-type hypersensitivy to Candida albicans, since it results in an excessive reaction of the immune system, is very difficult to diagnose. This study shows that the syndromic reaction observed after intradermal injection of an extract of Candida albicans, in patients suspected of abnormal delayed-type hypersensitivy to this antigen, is associated with the presence of specific circulating T cells, detectable through cell culture in the presence of Candida albicans. There is a very significant correlation between the clinical symptoms, the cutaneous tests, and the lymphocyte activation tests. This abnormal reactivity essentially involves the CD8 cells.

Antigens, CD↗
PubMed1997

[Diagnostic contribution of abnormal delayed-type hypersensitivity to Candida albicans. Characterization test by activation of cells sensitized to successive dilutions of Candida].

By measuring the activation of different cell models (lymphocytes and lymphocytic subsets) in the presence of Candida albicans with flow cytometry reading, it is possible to show that successive dilutions of Candida albicans can lead to lymphocyte activation in abnormally-sensitized subjects. In a first trial, 10 subjects were tested in duplicate. The decrease of activity of the dilutions does not appear to be regular in relation to the progression of the dilutions. The activity of the dilutions wanes relatively rapidly with the first dilutions, then recurs later very distinctly, at the 6th dilution, then ebbs, then reappears in similar manner at the 9th, the 14th, and finally, the 19th dilution. Cell reactivity appears to differ depending on the subject. It can be represented through the calculated slope of the regression line, for each series of data. It therefore appears feasible to determine a threshold of reactivity and a scale of sensitivity, to make it possible to specify the degree of abnormal reactivity existing at a given time for a given subject. The constancy of the activity of the different dilutions tested, on 10 cultures of a single cell suspension, is especially well demonstrated in the second trial, showing unusually small standard deviations. Thus, the question arises as to the exact nature of the observed phenomenon and of its analysis from a physical-chemical point of view, with regard to the pharmacological effect of successive dilutions of Candida albicans.

Adolescent↗
PubMed1993

Tonic activation of NMDA receptors causes spontaneous burst discharge of rat midbrain dopamine neurons in vivo.

Midbrain dopamine neurons in vivo discharge in a single-spike firing pattern or in a burst-firing pattern. Such activity in vivo strikingly contrasts with the pacemaker activity of the same dopamine neurons recorded in vitro. We have recently shown that burst activity in vivo of midbrain dopamine neurons is due to the local activation of excitatory amino acid receptors, as microapplication of the broad-spectrum antagonist of excitatory amino acids, kynurenic acid, strongly regularized the spontaneous firing pattern of these dopamine neurons. In the present study, we investigated which subtypes of excitatory amino acid receptors are involved in the burst-firing of midbrain dopamine neurons in chloral hydrate-anaesthetized rats, iontophoretic or pressure microejections of 6-cyano, 7-nitroquinoxaline-2,3-dione (CNQX), a non-N-methyl-D-aspartate (NMDA) receptor antagonist, did not alter the spontaneous burst firing of dopamine neurons (n = 36). In contrast, similar ejections of (+-)2-amino,5-phosphonopentanoic acid (AP-5), a specific antagonist at NMDA receptors, markedly regularized the firing pattern by reducing the occurrence of bursts (n = 52). In addition, iontophoretic ejections of NMDA, but not kainate or quisqualate, elicited a discharge of these dopamine neurons in bursts (n = 20, 12 and 14, respectively). These data suggest that burst-firing of midbrain dopamine neurons in vivo results from the tonic activation of NMDA receptors by endogenous excitatory amino acids. In view of the critical dependency of catecholamine release on the discharge pattern of source neurons, excitatory amino acid inputs to midbrain dopamine neurons may constitute a major physiological substrate in the control of the dopamine level in target areas.

Animals↗
PubMed1992

Inhibition of locus coeruleus neurons by the phencyclidine analog, N-[1-(2-benzo(b)thiophenyl)cyclohexyl]piperidine: evidence for potent indirect adrenoceptor agonist properties.

The effects of the phencyclidine derivative, N-[1-(2-benzo(b)thiophenyl)cyclohexyl]piperidine (BTCP), on the electrical activity of noradrenaline (NA) neurons of the locus coeruleus (LC) were studied in halothane-anesthetized rats. Systemic administration of BTCP potently inhibited LC neurons (ID50 of 1.1 +/- 0.1 mg/kg i.v.). This effect was mimicked by local microejection of BTCP into the LC. Both the systemic and local effects of BTCP were blocked by alpha 2-adrenoceptor antagonists and prevented by prior depletion of catecholamines with reserpine. These and other data suggest that BTCP behaves as a potent indirect NA agonist (i.e. via NA re-uptake and/or release systems).

Animals↗
PubMed1991

[Participation of NMDA receptors in spontaneous burst firing of dopaminergic mesencephalic neurons].

In the rat, somatodendritic application of the NMDA antagonist AP-5, within the Substantia Nigra Zona Compacta and Ventral Tegmental Area, either by micro-iontophoresis or pressure ejection, reduces burst firing of dopamine neurons. Similar local application of the non-NMDA antagonist CNQX does not affect their firing pattern. These results indicate that, in vivo, excitatory amino acid afferents participate through NMDA receptors in the control of the spontaneous burst firing of midbrain dopamine neurons.

Action Potentials↗