Papers by mohamed artham jamal
NOTCH plays a role in regulating stem cell function and fate decision. It is involved in tooth de... more NOTCH plays a role in regulating stem cell function and fate decision. It is involved in tooth development and injury repair. Information regarding NOTCH expression in human dental root apical papilla (AP) and its residing stem cells (SCAP) is limited. Here we investigated the expression of NOTCH3, its ligand JAG1, and mesenchymal stem cell markers CD146 and STRO-1 in the AP or in the primary cultures of SCAP isolated from AP. Our in situ immunostaining showed that in the AP NOTCH3 and CD146 were co‐expressed and associated with blood vessels having NOTCH3 located more peripherally. In cultured SCAP, NOTCH3 and JAG1 were co-expressed. Flow cytometry analysis showed that 7%, 16% and 98% of the isolated SCAP were positive for NOTCH3, STRO-1 and CD146, respectively with a rare 1.5% subpopulation of SCAP co-expressing all three markers. The expression level of NOTCH3 reduced when SCAP underwent osteogenic differentiation. Our findings are the first step towards defining the regulatory r...
Advances in Experimental Medicine and Biology, 2014
Different types of central venous catheters (CVCs) have been used in clinical practice to improve... more Different types of central venous catheters (CVCs) have been used in clinical practice to improve the quality of life of chronically and critically ill patients. Unfortunately, indwelling devices are usually associated with microbial biofilms and eventually lead to catheter-related bloodstream infections (CLABSIs).An estimated 250,000-400,000 CLABSIs occur every year in the United States, at a rate of 1.5 per 1,000 CVC days and a mortality rate of 12-25 %. The annual cost of caring for patients with CLABSIs ranges from 296 million to 2.3 billion dollars.Biofilm formation occurs on biotic and abiotic surfaces in the clinical setting. Extensive studies have been conducted to understand biofilm formation, including different biofilm developmental stages, biofilm matrix compositions, quorum-sensing regulated biofilm formation, biofilm dispersal (and its clinical implications), and multi-species biofilms that are relevant to polymicrobial infections.When microbes form a matured biofilm within human hosts through medical devices such as CVCs, the infection becomes resistant to antibiotic treatment and can develop into a chronic condition. For that reason, many techniques have been used to prevent the formation of biofilm by targeting different stages of biofilm maturation. Other methods have been used to diagnose and treat established cases of CLABSI.Catheter removal is the conventional management of catheter associated bacteremia; however, the procedure itself carries a relatively high risk of mechanical complications. Salvaging the catheter can help to minimize these complications.In this article, we provide an overview of microbial biofilm formation; describe the involvement of various genetic determinants, adhesion proteins, organelles, mechanism(s) of biofilm formation, polymicrobial infections, and biofilm-associated infections on indwelling intravascular catheters; and describe the diagnosis, management, and prevention of catheter-related bloodstream infections.
BMC infectious diseases, Jan 24, 2014
Central venous catheters (CVC) removal and reinsertion of a new CVC in the setting of central lin... more Central venous catheters (CVC) removal and reinsertion of a new CVC in the setting of central line associated bloodstream infections (CLABSI) is not always possible in septic patients. The purpose of this study was to evaluate the outcome of patients with Staphylococcus aureus-CLABSI (SA-CLABSI) who had their CVCs exchanged over guidewire for minocycline/rifampin-coated (M/R)-CVC within seven days of bacteremia. Each case was matched with two control patients who had SA-CLABSI and had their CVC removed within seven days and two control patients who had their CVC retained beyond seven days. In addition, an in vitro model was developed for exchange of catheters. We identified 40 patients with SA-CLABSI. Eight patients had their CVC exchanged over guidewire with M/R-CVC and were compared to 16 patients who had their CVC removed and 16 other patients who had their CVC retained. Patients who had their CVC exchanged over guidewire had a similar clinical response and relapse rates compared...
Antimicrobial agents and chemotherapy, 2014
Exchanging a central venous catheter (CVC) over a guide wire for a fresh uncoated CVC in the pres... more Exchanging a central venous catheter (CVC) over a guide wire for a fresh uncoated CVC in the presence of bacteremia can result in cross-infection of the newly exchanged CVC. A recent retrospective clinical study showed that exchanging a catheter over a guide wire in the presence of bacteremia using an antimicrobial minocycline-rifampin (M/R) catheter may improve outcomes. To expand on this, we developed an in vitro cross-contamination model of exchange to evaluate the efficacy of different antimicrobial CVCs in preventing cross-contamination of multidrug-resistant organisms during exchange. Uncoated CVCs were allowed to form biofilm by methicillin-resistant Staphylococcus aureus (MRSA), Staphylococcus epidermidis, Escherichia coli, Pseudomonas aeruginosa, and Candida albicans. After 24 h, the biofilm-colonized CVCs were placed in a glass tube containing bovine calf serum plus Mueller-Hinton broth, and each catheter was exchanged over a guide wire for a fresh uncoated or an M/R-, chl...
This work investigates the conduction band structure of silicon nanowires, its dependence with th... more This work investigates the conduction band structure of silicon nanowires, its dependence with the wire width and its influences on the electrical performances of Si nanowire-based MOSFET's working in the ballistic regime. The energy dispersions relations for Si nanowires have been calculated using a sp 3 tight-binding model and the ballistic response of n-channel devices with a 3D Poisson-Schrö dinger solver considering a mode-space approach and open boundary conditions (NEGF formalism). Results are compared with data obtained considering the parabolic bulk effective mass approximation, highlighting in this last case the overestimation of the I on current, up to 60% for the smallest (1.36 nm • 1.36 nm Si wire) devices.
This work investigates the conduction band structure of silicon nanowires, its dependence with th... more This work investigates the conduction band structure of silicon nanowires, its dependence with the wire width and its influences on the electrical performances of Si nanowire-based MOSFET's working in the ballistic regime. The energy dispersions relations for Si nanowires have been calculated using a sp 3 tight-binding model and the ballistic response of n-channel devices with a 3D Poisson-Schrö dinger solver considering a mode-space approach and open boundary conditions (NEGF formalism). Results are compared with data obtained considering the parabolic bulk effective mass approximation, highlighting in this last case the overestimation of the I on current, up to 60% for the smallest (1.36 nm • 1.36 nm Si wire) devices.
Journal of Medical …, 2011
Abstract: Advances have been made in identifying dental stem cells and their differentiation pote... more Abstract: Advances have been made in identifying dental stem cells and their differentiation potential. Five different types of dental stem cells have been isolated from dental soft tissues: dental pulp, apical papilla, dental follicle and periodontal ligament. The characteristic ...
Antimicrobial Agents and Chemotherapy, 2014
ABSTRACTResistant Gram-negative bacteria are increasing central-line-associated bloodstream infec... more ABSTRACTResistant Gram-negative bacteria are increasing central-line-associated bloodstream infection threats. To better combat this, chlorhexidine (CHX) was added to minocycline-rifampin (M/R) catheters. Thein vitroantimicrobial activity of CHX-M/R catheters against multidrug resistant, Gram-negativeAcinetobacter baumannii,Enterobacter cloacae,Escherichia coli,Klebsiella pneumoniae,Pseudomonas aeruginosa, andStenotrophomonas maltophiliawas tested. M/R and CHX-silver sulfadiazine (CHX/SS) catheters were used as comparators. The novel CHX-M/R catheters were significantly more effective (P< 0.0001) than CHX/SS or M/R catheters in preventing biofilm colonization and showed better antimicrobial durability.
Antimicrobial Agents and Chemotherapy, 2014
ABSTRACTResistant Gram-negative bacteria are increasing central-line-associated bloodstream infec... more ABSTRACTResistant Gram-negative bacteria are increasing central-line-associated bloodstream infection threats. To better combat this, chlorhexidine (CHX) was added to minocycline-rifampin (M/R) catheters. Thein vitroantimicrobial activity of CHX-M/R catheters against multidrug resistant, Gram-negativeAcinetobacter baumannii,Enterobacter cloacae,Escherichia coli,Klebsiella pneumoniae,Pseudomonas aeruginosa, andStenotrophomonas maltophiliawas tested. M/R and CHX-silver sulfadiazine (CHX/SS) catheters were used as comparators. The novel CHX-M/R catheters were significantly more effective (P< 0.0001) than CHX/SS or M/R catheters in preventing biofilm colonization and showed better antimicrobial durability.
Medical Principles …, 2000
Objective: To retrospectively analyse all laparoscopic cholecystectomies performed between April ... more Objective: To retrospectively analyse all laparoscopic cholecystectomies performed between April 1992 and May 1999. Methods: Medical records of 2,750 patients, clinically diagnosed with gall bladder disease, were reviewed. We analysed the operative time, length of ...
European Archives of Oto-Rhino-Laryngology, 1994
Five cases of juvenile angiofibroma are reported. The nose and nasopharynx were involved in four ... more Five cases of juvenile angiofibroma are reported. The nose and nasopharynx were involved in four cases and the nose and right maxillary sinus in one. Presenting symptoms were epistaxis and nasal blockage while two patients also had dacryocystitis and secretory otitis media. All patients had CT scans done and magnetic resonance imaging was required for two patients. Angiography with embolization of both internal maxillary arteries was performed in all patients. Biopsies were taken in three patients but no blood transfusion was needed. Tumor resection were then done, using a transpalatal approach in four cases. Ligation of the external carotid artery was carried out in one patient who had tumor recurrence with disappearance of the remaining part of the tumor occurring 6 months after the ligation. Although no conclusions can be reached from one case, a question can be raised as to whether this method should be used.
Antimicrobial agents and chemotherapy, Jan 29, 2015
Antimicrobial Peripherally inserted central catheters (PICCs) might reduce the incidence of CLABS... more Antimicrobial Peripherally inserted central catheters (PICCs) might reduce the incidence of CLABSI. We tested biocompatibility of a novel gendine (combination of chlorhexidine-CHX and gentian violet-GV) PICC in a rabbit intravascular model and tested antimicrobial efficacy in comparison with commercially available minocycline/rifampin (M/R), and CHX PICCs in an in vitro biofilm colonization model.Gendine and uncoated control PICCs were inserted in the jugular veins of rabbits for 4 days. Histopathologic analysis was performed at the end of the four day period and circulating levels of CHX and GV in blood were measured at different time points using liquid chromatography/mass spectrometry. Antimicrobial efficacy of the PICCs were tested following simulated intravascular indwells of 24 hours and 1 week against clinical isolates of methicillin-resistant Staphylococcus aureus, Vancomycin-resistant enterococci Pseudomonas aeruginosa, Escherichia coli, Acinetobacter baumannii, Enterobacte...
Birck and NCN Publications, 2009
An atomistic full-band quantum transport simulator has been developed to study three-dimensional ... more An atomistic full-band quantum transport simulator has been developed to study three-dimensional Si nanowire field-effect transistors (FETs) in the presence of electron-phonon scattering. The Non-equilibrium Green's Function (NEGF) formalism is solved in a nearest-neighbor sp (3) d (5) s* tight-binding basis. The scattering self-energies are derived in the self-consistent Born approximation to inelastically couple the full electron and phonon energy spectra. The band dispersion and the eigenmodes of the confined phonons are ...
Birck and NCN Publications, 2009
An atomistic full-band quantum transport simulator has been developed to study three-dimensional ... more An atomistic full-band quantum transport simulator has been developed to study three-dimensional Si nanowire field-effect transistors (FETs) in the presence of electron-phonon scattering. The Non-equilibrium Green's Function (NEGF) formalism is solved in a nearest-neighbor sp (3) d (5) s* tight-binding basis. The scattering self-energies are derived in the self-consistent Born approximation to inelastically couple the full electron and phonon energy spectra. The band dispersion and the eigenmodes of the confined phonons are ...
Teaching Documents by mohamed artham jamal
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Papers by mohamed artham jamal
Teaching Documents by mohamed artham jamal