Montreal Children's Hospital

About: Montreal Children's Hospital is a healthcare organization based out in Montreal, Quebec, Canada. It is known for research contribution in the topics: Population & Poison control. The organization has 3842 authors who have published 4816 publications receiving 200198 citations.

Apoptotic Cell Death in Mouse Models of GM2 Gangliosidosis and Observations on Human Tay-Sachs and Sandhoff Diseases

Abstract: Tay-Sachs and Sandhoff diseases are autosomal recessive neurodegenerative diseases resulting from the inability to catabolize GM2 ganglioside by beta-hexosaminidase A (Hex A) due to mutations of the alpha subunit (Tay-Sachs disease) or beta subunit (Sandhoff disease) of Hex A. Hex B (beta beta homodimer) is also defective in Sandhoff disease. We previously developed mouse models of both diseases and showed that Hexa-/- (Tay-Sachs) mice remain asymptomatic to at least 1 year of age while Hexb-/- (Sandhoff) mice succumb to a profound neurodegenerative disease by 4-6 months of age. Here we find that neuron death in Hexb-/- mice is associated with apoptosis occurring throughout the CNS, while Hexa-/- mice were minimally involved at the same age. Studies of autopsy samples of brain and spinal cord from human Tay-Sachs and Sandhoff diseases revealed apoptosis in both instances, in keeping with the severe expression of both diseases. We suggest that neuron death is caused by unscheduled apoptosis, implicating accumulated GM2 ganglioside or a derivative in triggering of the apoptotic cascade.

Mutations in the calcium-related gene IL1RAPL1 are associated with autism

Abstract: In a systematic sequencing screen of synaptic genes on the X chromosome, we have identified an autistic female without mental retardation (MR) who carries a de novo frameshift Ile367SerfsX6 mutation in Interleukin-1 Receptor Accessory Protein-Like 1 (IL1RAPL1), a gene implicated in calcium-regulated vesicle release and dendrite differentiation. We showed that the function of the resulting truncated IL1RAPL1 protein is severely altered in hippocampal neurons, by measuring its effect on neurite outgrowth activity. We also sequenced the coding region of the close related member IL1RAPL2 and of NCS-1/FREQ, which physically interacts with IL1RAPL1, in a cohort of subjects with autism. The screening failed to identify non-synonymous variant in IL1RAPL2, whereas a rare missense (R102Q) in NCS-1/FREQ was identified in one autistic patient. Furthermore, we identified by comparative genomic hybridization a large intragenic deletion of exons 3-7 of IL1RAPL1 in three brothers with autism and/or MR. This deletion causes a frameshift and the introduction of a premature stop codon, Ala28GlufsX15, at the very beginning of the protein. All together, our results indicate that mutations in IL1RAPL1 cause a spectrum of neurological impairments ranging from MR to high functioning autism.

Exploitation of Astrocytes by Glioma Cells to Facilitate Invasiveness: A Mechanism Involving Matrix Metalloproteinase-2 and the Urokinase-Type Plasminogen Activator–Plasmin Cascade

Abstract: The presence of reactive astrocytes around glioma cells in the CNS suggests the possibility that these two cell types could be interacting. We addressed whether glioma cells use the astrocyte environment to modulate matrix metalloproteinase-2 (MMP-2), a proteolytic enzyme implicated in the invasiveness of glioma cells. We found that astrocytes in culture produce significant amounts of the pro-form of MMP-2 but undetectable levels of active MMP-2. However, after coculture with the U251N glioma line, astrocyte pro-MMP-2 was converted to the active form. The mechanism of pro-MMP-2 activation in glioma-astrocyte coculture was investigated and was found to involve the urokinase-type plasminogen activator (uPA)-plasmin cascade whereby uPA bound to uPA receptor (uPAR), leading to the conversion of plasminogen to plasmin. The latter cleaved pro-MMP-2 to generate its active form. Furthermore, key components (i.e., uPAR, uPA, and pro-MMP-2) were contributed principally by astrocytes, whereas the U251N glioma cells provided plasminogen. In correspondence with this biochemical cascade, the transmigration of U251N cells through Boyden invasion chambers coated with an extracellular matrix barrier was increased significantly in the presence of astrocytes, and this was inhibited by agents that disrupted the uPA-plasmin cascade. Finally, using resected human glioblastoma specimens, we found that tumor cells, but not astrocytes, expressed plasminogen in situ. We conclude that glioma cells exploit their astrocyte environment to activate MMP-2 and that this leads to the increased invasiveness of glioma cells.

Long-acting beta2-agonists versus anti-leukotrienes as add-on therapy to inhaled corticosteroids for chronic asthma.

Abstract: Background Patients who continue to experience asthma symptoms despite taking regular inhaled corticosteroids (ICS) represent a management challenge. Leukotriene receptor antagonists (LTRA) and long-acting beta(2)-agonists (LABA) agents may both be considered as add-on therapy to inhaled corticosteroids (ICS). Objectives We compared the efficacy and safety profile of adding either daily LABA or LTRA in asthmatic patients who remained symptomatic on ICS. Search strategy The Cochrane Airways Group Specialised Register was searched for randomised controlled trials up to and including March 2006. Reference lists of all included studies and reviews were screened to identify potentially relevant citations. Inquiries regarding other published or unpublished studies supported by the authors of the included studies or pharmaceutical companies who manufacture these agents were made. Conference proceedings of major respiratory meetings were also searched. Selection criteria Only randomised controlled trials conducted in adults or children with recurrent asthma where a LABA (for example, salmeterol or formoterol) or LTRA (for example, montelukast, pranlukast, zafirlukast) was added to ICS for a minimum of 28 days were considered for inclusion. Inhaled short-acting beta(2)-agonists and short courses of oral steroids were permitted as rescue medications. Other daily asthma treatments were permitted, providing the dose remained constant during the intervention period. Two reviewers independently reviewed the literature searches. Data collection and analysis Data extraction and trial quality assessment were conducted independently by two reviewers. Whenever possible, primary study authors were requested to confirm methodology and data extraction and to provide additional information and clarification when needed. Where necessary, expansion of graphic reproductions and estimation from other data presented in the paper was performed. Main results Fifteen randomised controlled trials met the inclusion criteria; eleven trials including 6,030 participants provided data in sufficient detail to permit aggregation. All eleven trials pertained to adults with moderate airway obstruction (% predicted FEV(1) 66-76%) at baseline. Montelukast (n=9) or Zafirlukast (n=2) was compared to Salmeterol (n=9) or Formoterol (n=2) as add-on therapy to 400-565 mcg of beclomethasone or equivalent. Risk of exacerbations requiring systemic corticosteroids was significantly lower with LABA+ICS when compared to LTRA+ICS (RR= 0.83, 95% Confidence Interval (95%CI): 0.71, 0.97): the number needed to treat with LABA compared to LTRA, to prevent one exacerbation over 48 weeks, was 38 (95% CI: 23 to 247). The following outcomes also improved significantly with the addition of LABA compared to LTRA to inhaled steroids (Weighted Mean Difference; 95%CI): morning PEFR (16 L/min; 13 to 18), evening PEFR (12 L/min; 9 to 15), FEV(1) (80 mL; 60 to 100), rescue-free days (9%; 5% to 13%), symptom-free days (6%; 2 to 11), rescue beta(2)-agonists (-0.5 puffs/day; -0.2 to -1), quality of life (0.1; 0.05 to 0.2), symptom score (Standard Mean Difference -0.2; -0.1 to -0.3), night awakenings (-0.1/week; -0.06 to -0.2) and patient satisfaction (RR 1.12; 1.07 to 1.16). Risk of withdrawals due to any reason was significantly lower with LABA+ICS compared to LTRA+ICS (Risk Ratio 0.83, 95% CI 0.73 to 0.95). Withdrawals due to adverse events or due to poor asthma control, hospitalisation, osteopenia, serious adverse events, overall adverse events, headache or cardiovascular events were not significantly different between the two study groups. Authors' conclusions In asthmatic adults inadequately controlled on low doses of inhaled steroids, the addition of LABA is superior to LTRA for preventing exacerbations requiring systemic steroids, and for improving lung function, symptoms, and the use of rescue beta(2)-agonists.

Characterization of four novel epithelial ovarian cancer cell lines

Abstract: Dear Editor: Epithelial ovarian cancer (EOC) is the most lethal gynecologic malignancy. EOCs originate from either the surface epithelium itself or from the crypts or inclusion cysts on the surface epithelium of the ovary (Whitman et al., 1993). EOCs are designated according to their cell type: serous, mucinous, endometrioid, clear cell, Brenner, or undifferentiated (Serov et al., 1973). They are graded according to degree of differentiation: borderline or low malignant potential represent minimal deviation from their benign counterpart while well differentiated tumors are grade 1, moderately differentiated are grade 2, and poorly differentiated are grade 3 carcinomas. At surgery EOCs are also classified according to stage, grade and amount of residual disease based on criteria established by the International Federation of Gynecology and Obstetrics (FIGO). A common behavior of EOC (in one-third of all cases) is seeding of the peritoneal fluid leading to subsequent implantation over peritoneal surfaces with ascites formation (Morrow and Curtin, 1998). EOCs can arise sporadically and in rarer instances in association with familial cancer syndromes (Easton et al., 1993). It is presently unclear whether the underlying molecular events in the development of all EOCs are similar or whether distinct events are associated with particular subtypes. We have previously described an efficient and rapid technique for the establishment of primary cultures from EOC (Lounis et al., 1994). While these primary cultures are ideally suited to certain studies, the major drawback is the inability to maintain these cultures over extended periods for long-term experiments and for tumor assays. Most human ovarian cancer cell lines described were derived from ascites or pleural effusion (DiSaia et al., 1975; Fogh and Trcmpe, 1975; Sinna et al., 1979; Bast et al,, 1981; Hamilton et al., 1983; Langdon et al., 1988; Golombick et al., 1990; Wong et al., 1990; Golombick and Bezwda, 1991; Yamada et al., 1991; Grunt et al., 1993; Provencher et al., 1993; Hirte et al., i994; Buller et al., 1995; Alama et al., 1996), with only a few cell lines derived from primary ovarian solid tumors (Woods et al., 1979; Langdon et al., 1988; Crickard et al., 1989) or metastases (Buick et al., 1985). In addition, most cell lines originate from tumor material obtained following adjuvant therapy such as chemotherapy or radiation therapy, which could introduce confounding genetic events. Following the derivation of primary EOC cultures (Lounis et al., 1994), we were able to establish four independent spontaneously immortalized epithelial ovarian cancer cell lines from patients who were never exposed to chemotherapy or radiation therapy. The cell lines were derived from ovarian malignant tumors (TOV-21G, TOV-81D, and TOV-112D) and from an ovarian malignant ascites (OV-90). The ovarian tumor cell lines are derived from different histopathologies of ovarian tumors: a clear cell carcinoma (TOV-21G), a papillary serous adenocarcinoma (TOV-81D), an endometrioid carcinoma (TOV-112D), and an adenocarcinoma (OV-90). The clinical information is summarized in Table 1. All patients were diagnosed with advanced disease. Three tumors were grade 3 while one, TOV-81D, was classified as grade 1-2. In Canada, the average age at diagnosis is 54 yr (NCIC, 1999) and therefore TOV112D was derived from a patient with early age of onset ovarian cancer (42 yr at the time of diagnosis). This patient survived less then 3 mo despite an optimal cytoreduetive surgical procedure and platinol-based chemotherapy. TOV-81D is particularly interesting since it was derived from a patient with a familial history of breast and ovarian cancer. In this patient the disease was rather indolent with relapse occurring greater than 5 yr later. Since all the cell lines described here were derived from women of French-Canadian descent they were screened for mutations found to occur in this population (Tonin et al., 1998). Through these studies it was possible to identify a germline BRCA2 mutation, a nucleotide 8765delAG mutation in exon 20, in TOV-81D. All cell lines expressed BRCA1 and BRCA2 as detected by reverse transcriptasepolymerase chain reaction (RT-PCR). Three of the cell lines grow as monolayer cultures on a solid surface (TOV-21G, TOV-81D, and OV-90) while the TOV-112D cell line is loosely adherent and the cells have a tendency to compact and form foci. TOV-81D cells have a very flat morphology and are large surface cells with abundant cytoplasm (Fig. 1D). The epithelial morphology is highly similar to the morphology of cell cultures derived from normal ovarian epithelium (Lounis et al., 1994) and resembles the morphology of a previously described ovarian cell line SKOV-3 (Fogh and Trempe, 1975) which was established from the ascites of a patient with an ovarian adenocarcinoma (Fig. 1E). In contrast, the cellular morphology of the TOV-21G (Fig. 1A), TOVl12D (Fig. 1B), and OV-90 (Fig. 1C) differ from SKOV-3, with ceils being generally smaller and more refractile (Fig. 1). In particular, the OV-90 cells maintain a classic morphology, characterized by ruffled membranes (Lounis et al., 1994), which have been observed in primary cultures from ovarian ascites. The expression of epithelial specific keratins was verified (Table 2). The TOV-21G, OV-90, and TOV-112D cell lines show strong immunofluorescence against the keratin specific CAM5.2 antibody while the TOV-81D cell line reacted weakly with the CAM5.2 antibody. Staining was as reported previously for OV and TOV cultures (Lounis et al., 1994) and was consistent with a staining pattern associated with transformed calls. In addition, we have assessed the expression of antigens MH99 (Mattes et al., 1983, 1987) and B72.3 whose expression correlates with epithelial ovarian carcinomas (Thor et al.~ 1986). All cell lines showed strong positive immunofluorescent staining for both MH99 and B72.3, and this staining appeared stronger than the staining pattern observed for SKOV-3 (Table 2). Staining for CAM5.2, MH99, and B72.1 were negative in the NIH3T3 fibroblast control cell line (Table 2). Finally, the expression of the HER2/NEU oncogene, has been associated with poor prognosis in ovarian cancer (Slamon et al., 1989), was determined. All four ovarian cell lines express neu to some extent