Ghassan S. Dbaibo

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Proteases are now firmly established as major regulators of the "execution" phase of apoptosis. Here, we examine the role of proteases and their relationship to ceramide, a proposed mediator of apoptosis, in the tumor necrosis factor-alpha (TNF-alpha)-induced pathway of cell death. Ceramide induced activation of prICE, the protease that cleaves the death(More)
We describe the ninth variant of neuronal ceroid lipofuscinosis (NCL) or Batten disease, due to defects in a putative new gene, CLN9. We therefore refer to the new variant as CLN9-deficient. Two Serbian sisters and two German brothers are described. Their clinical history is characteristic for juvenile NCL. They show similar gene expression patterns. The(More)
The sphingolipid ceramide mediates various cellular processes in response to several extracellular stimuli. Some genotoxic stresses are able to induce p53-dependent ceramide accumulation leading to cell death. However, in other cases, in the absence of the tumor suppressor protein p53, apoptosis proceeds partly due to the activity of this "tumor suppressor(More)
The contribution of B cells to the pathology of Omenn syndrome and leaky severe combined immunodeficiency (SCID) has not been previously investigated. We have studied a mut/mut mouse model of leaky SCID with a homozygous Rag1 S723C mutation that impairs, but does not abrogate, V(D)J recombination activity. In spite of a severe block at the pro-B cell stage(More)
Human infections with H5, H7, and H9 avian influenza viruses are well documented. Exposure to poultry is the most important risk factor for humans becoming infected with these viruses. Data on human infection with other low pathogenicity avian influenza viruses is sparse but suggests that such infections may occur. Lebanon is a Mediterranean country lying(More)
Immunogenicity and safety of ACWY-TT compared with licensed ACWY polysaccharide vaccine (MenPS) in healthy adults, and lot-to-lot consistency of three ACWY-TT lots were evaluated in a phase III, open, controlled study. Adults aged 18–55 years were randomized to receive ACWY-TT (one of three lots) or MenPS. Serum bactericidal antibodies (rSBA) were measured(More)
BACKGROUND In inflammatory bowel disease (IBD), cytokine levels (such as interleukin-1 (IL-1)) are elevated. We have shown previously that IL-1 activates phospholipid signaling pathways in intestinal epithelial cells (EEC), leading to increased ceramide levels. AIM To determine whether ceramide induces apoptosis in IEC. METHODS Apoptosis was evaluated(More)
Co-administration of meningococcal serogroups A, C, W-135 and Y conjugate vaccine (ACWY-TT) with seasonal influenza vaccine was investigated in a subset of adults enrolled in a larger study evaluating lot-to-lot consistency of ACWY-TT and non-inferiority to licensed tetravalent meningococcal polysaccharide vaccine (MenPS). Subjects in this sub-study were(More)
Status epilepticus (SE) induces a number of events leading to programmed cell death (PCD). The aim of our work is to study the time sequence of activation of different factors in experimental SE (intraperitoneal kainic acid (KA) model). We studied ceramide, a known mediator of apoptosis in multiple models, sphingomyelinases (SMases), enzymes that break down(More)