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Biomedical subjects

J M Girard

Publications and source records attributed to J M Girard.

13 recordsLinked to original sources
PubMed1996

Traumatic neuroprotection with inhibitors of nitric oxide and ADP-ribosylation.

N-Methyl-D-aspartate (NMDA) receptor activation is known to contribute to neuronal damage from head trauma. Additionally, NMDA neurotoxicity occurs in part through the generation of nitric oxide (NO), and injury from NO has been shown to be mediated by ADP-ribosylation. Therefore, we investigated whether inhibitors of NO and ADP-ribosylation would protect against acute CA1 traumatic neuronal injury in hippocampal slices subjected to fluid percussion. Treatment with the nitric oxide synthase (NOS) inhibitor, methyl-L-arginine 170 microM for 35 min after trauma injury, improved CA1 antidromic population spike (PS) recovery to 91 +/- 2%, compared to unmediated slices which recovered to only a mean of 20 +/- 4%, 90 min after trauma. Similarly, hemoglobin 50 microM, which directly binds NO, protected against traumatic neuronal injury and yielded a mean CA1 PS recovery of 92 +/- 1%. Treatment with inhibitors of poly-ADP-ribosylation was also strongly protective, with the vitamin nicotinamide 10 mM and 3-aminobenzamide 1 mM yielding PS recoveries of 98 +/- 2% and 90 +/- 3%, respectively. Protection was also seen with inhibitors of mono-ADP-ribosylation, including novobiocin 500 microM and meta-iodobenzylguanidine 20 microM which yielded recoveries of 89 +/- 6% and 96 +/- 26%. Novobiocin also protected against direct application of NO and NMDA. These findings suggest that NO and ADP-ribosylation are mediators of acute traumatic neuronal injury.

Adenosine Diphosphate Ribose↗
PubMed1994

Selective enrichment of Th1 CD45RBlow CD4+ T cells in autoimmune infiltrates in experimental allergic encephalomyelitis.

The cytokine effector status of CD4+ T cells from lymph nodes (LN) and the central nervous system (CNS) of SJL/J mice immunized with autoantigen in adjuvant for the induction of experimental allergic encephalomyelitis (EAE) was compared. CD4+ T cells were FACS sorted based on the levels of expression of the activation marker CD45RB. Low levels of expression of this surface marker are induced by antigen recognition and are associated with 'effector' T cell function. Reverse transcriptase polymerase chain reaction (PCR) was used to analyze the expression of different T cell cytokine genes in the sorted populations. CD45RBlow cells constituted a minority of CD4+ cells in the LN and expressed elevated levels of IL-2, IFN-gamma, and IL-4 mRNA, whereas the CD45RBlow CD4+ population did not express detectable message for these cytokines under linear PCR conditions. By contrast to the LN, CD4+ cells from the CNS were predominantly CD45RBlow and expressed readily detectable levels of IL-2 and IFN-gamma mRNA, but almost no IL-4 transcription could be detected. IL-4 mRNA levels in CNS were 100- to 250-fold lower than in LN. Also, IL-4 message could not be detected in the CNS 1 week after remission. A cytokine-specific immunocytochemical single cell staining technique was used to enumerate cytokine-producing cells in LN cell populations and in CNS infiltrates. Between 1 and 5% cells in isolated LN cells produced detectable IL-2 and IFN-gamma. By contrast, the frequency of cytokine-producing cells stained in perivascular infiltrates in frozen sections from the brains of animals with active EAE was 10-fold higher.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

[Value of gradient echo MRI in patellar chondromalacia].

The use of MRI in the evaluation of cartilaginous lesions is now well established. Thirty patients suspected of presenting such lesions were investigated by MRI with gradient echo sequences. Twelve patients had an arthroscopy either before or after the MRI. The sequences have allowed characterisation of the lesions of chondromalacia and have showed early lesions not visible at arthroscopy, without need for intraarticular contrast injection.

Arthroscopy↗
PubMed1991

[Magnetic resonance imaging in fractures caused by fatigue and by insufficiency].

The only important complication of a stress fracture is the true fracture. For this reason, a diagnostic should be made as fast as possible. 30 patients with stress fractures, whose 10 with magnetic resonance imaging are presented and the different radiological technics are compared. The magnetic resonance imaging, showing the first modifications inside the medullary cavity, allows a quick diagnosis in very difficult cases, when the other technics have not given the answer.

Adolescent↗