Publications by authors named "Muejdat Gueller"

The annual meeting for the Intermountain Branch was held in April 2024 on the campus of Brigham Young University. There were 127 branch members from Utah, Idaho, and Nevada who attended the meeting and were composed of undergraduate students, graduate or medical students, and faculty. This report highlights the diversity of, and the emerging trends in, the research conducted by American Society for Microbiology members in the Intermountain Branch.

View Article and Find Full Text PDF

Background: Early detection of recurrence through surveillance after curative surgery for primary colon cancer is recommended. We previously reported inadequate quality of surveillance among patients operated for colon cancer. These poor results led to the introduction of a personalized surveillance schedule.

View Article and Find Full Text PDF

Introduction: Respiratory syncytial virus (RSV) is a frequent cause of respiratory tract infectious disease (RTID) in allogeneic hematopoietic stem cell transplant (HSCT) recipients associated with a high mortality once infection has progressed from upper RTID (URTID) to lower RTID (URTID). Aerosolized ribavirin (RBV) is considered a cornerstone of treatment, but is expensive and has toxic side effects on patients and staff. In this study, RSV infection was detected by polymerase chain reaction (PCR) from routinely collected throat swabs in HSCT patients.

View Article and Find Full Text PDF

Fms-like tyrosine kinase 3 (FLT3) is a receptor tyrosine kinase with important roles in hematopoietic progenitor cell survival and proliferation. It is mutated in approximately one-third of AML patients, mostly by internal tandem duplications (ITDs). Adaptor protein Lnk is a negative regulator of hematopoietic cytokine signaling.

View Article and Find Full Text PDF

Objective: To investigate severe maternal morbidity/near misses in a tertiary public maternity in the state of Rio de Janeiro, using different identification criteria.

Methods: This is a cross-sectional study, performed in a regional reference hospital between June and October 2009, on severe maternal morbidity/near miss cases identified from the log books of the maternity hospital and review of medical records. This study focused on women who, during pregnancy, delivery, or the postpartum period, showed no clinical symptoms compatible with the defining criteria for severe maternal morbidity/near miss of Waterstone et al, Mantel et al.

View Article and Find Full Text PDF

Seroconversion rates following influenza vaccination in patients with hematologic malignancies after hematopoietic stem cell transplantation (HSCT) are known to be lower compared to healthy adults. The aim of our diagnostic study was to determine the rate of seroconversion after 1 or 2 doses of a novel split virion, inactivated, AS03-adjuvanted pandemic H1N1 influenza vaccine (A/California/7/2009) in HSCT recipients (ClinicalTrials.gov Identifier: NCT01017172).

View Article and Find Full Text PDF

Objective: Platelet-derived growth factor receptors α and β (PDGFRA, PDGFRB) are frequently expressed on hematopoietic cells and regulate cellular responses such as proliferation, differentiation, survival, and transformation. Stimulation by autocrine loops or activation by chromosomal translocation makes them important factors in development of hematopoietic disorders. Interaction with the ligand PDGF results in activation of the tyrosine kinase domain and phosphorylation of tyrosine residues, thereby creating binding sites for molecules containing Src homology 2 domains.

View Article and Find Full Text PDF

Objective: Development of myelodysplastic syndrome (MDS) is suggested to follow a multistep pathogenesis and is characterized by accumulation of molecular defects of the hematopoietic stem/progenitor cells, resulting in aberrant differentiation and proliferation.

Materials And Methods: To detect alterations within the transcriptional program in MDS-derived CD34(+) cells during lineage-specific differentiation, we performed serial gene expression analysis of in vitro differentiated erythro-, granulo-, and megakaryopoietic cells using oligonucleotide microarrays (HG-U133A, Affymetrix, Santa Clara, CA, USA). For selected genes, expression data were confirmed using real-time polymerase chain reaction.

View Article and Find Full Text PDF

The M-CSFR (c-Fms) participates in proliferation, differentiation, and survival of macrophages and is involved in the regulation of distinct macrophage functions. Interaction with the ligand M-CSF results in phosphorylation of tyrosine residues on c-Fms, thereby creating binding sites for molecules containing SH2 domains. Lnk is a SH2 domain adaptor protein that negatively regulates hematopoietic cytokine receptors.

View Article and Find Full Text PDF

Objective: Mantle cell lymphoma (MCL) is a lymphoma characterized by aberrant activation of CCND1/cyclin D1 followed by sequential genetic abnormalities. Genomic abnormalities in MCL have been extensively examined by classical cytogenetics and microarray-based comparative genomic hybridization techniques, pointing out a number of alterations in genomic regions that correlate with the neoplastic phenotype and survival. Recently, single nucleotide polymorphism genomic microarrays (SNP-chip) have been developed and used for analysis of cancer genomics.

View Article and Find Full Text PDF

RNA quality is critical to achieve valid results in microarray experiments and to save resources. The RNA integrity number (RIN) can be measured with minimal sample consumption by microfluidics-based capillary electrophoresis. To determine whether RIN can predict the qualitative outcome of microarray hybridization, we measured RIN in total RNA samples from 484 different experiments by the 2100 Bioanalyzer system and correlated with the percentage of present calls (%pc) of downstream oligonucleotide microarrays.

View Article and Find Full Text PDF

Objective: Tyrosine kinases are involved in cytokine signaling and are frequently aberrantly activated in hematological malignancies. Lnk, a negative regulator of cytokine signaling, plays critical nonredundant roles in hematopoiesis. By binding to phosphorylated tyrosine kinases, Lnk inhibits major cytokine receptor signaling, including c-KIT; erythropoietin receptor-Janus kinase 2 (JAK2); and MPL-JAK2.

View Article and Find Full Text PDF

The JAK2 mutation JAK2V617F is found frequently in patients with myeloproliferative disorders (MPD) and transforms hematopoietic cells to cytokine-independent proliferation when expressed with specific cytokine receptors. The Src homology 2 (SH2) and pleckstrin homology (PH) domain-containing adaptor protein Lnk (SH2B3) is a negative regulator of hematopoietic cytokine signaling. Here, we show that Lnk is a potent inhibitor of JAK2V617F constitutive activity.

View Article and Find Full Text PDF

LY573636-sodium is a promising anti-tumor agent, which causes growth arrest and apoptosis of a variety of human solid tumors in vitro and in vivo. Moreover, studies have shown that the compound is selectively toxic towards tumor cells over their normal counterparts. This targeted effect makes LY573636 a candidate for combined therapy regimens in patients with advanced or resistant cancers.

View Article and Find Full Text PDF

The adaptor protein Lnk is expressed in haemopoietic cells and plays a critical role in haemopoiesis. Animal model studies demonstrated that Lnk acts as a broad inhibitor of signalling pathways in haemopoietic lineages. Lnk belongs to a family of proteins sharing several structural motifs, including an SH2 (Src homology 2) domain which binds phosphotyrosine residues in various signal-transducing proteins.

View Article and Find Full Text PDF

Cucurbitacins have long been utilized for their abortifacient and anti-inflammatory effects; however, little is known about their mechanism of action. In this study, we have demonstrated robust antiproliferative effects of CuB on various leukemia and lymphoma cell lines, as well as on primary mononuclear bone marrow cells derived from patients with acute myeloid leukemia or myelodysplastic syndrome. Myeloid leukemic cells treated with CuB exhibit significant S-phase cell cycle arrest, enlarged cell size, multinucleation, and enhanced expression of a monocytic- and granulocytic-specific CD11b.

View Article and Find Full Text PDF

Recently, activating myeloproliferative leukemia virus oncogene (MPL) mutations, MPLW515L/K, were described in myeloproliferative disorder (MPD) patients. MPLW515L leads to activation of downstream signaling pathways and cytokine-independent proliferation in hematopoietic cells. The adaptor protein Lnk is a negative regulator of several cytokine receptors, including MPL.

View Article and Find Full Text PDF

We report the case of a 25-year-old, hepatitis C-infected man, who presented with severe rhabdomyolysis and acute renal failure, and later developed posterior encephalopathy with cortical blindness after the ingestion of magic mushrooms. Conventional respiratory and cardiovascular support including mechanical ventilation, continuous veno-venous hemodialysis and corticosteroids led to improvement and the patient recovered completely over the following months. Magic mushrooms are becoming increasingly fashionable among drug users, as they are believed to be more harmless than other hallucinogenic designer drugs.

View Article and Find Full Text PDF

The Advanced Burn Life Support Course has been used to train military physicians and nurses for more than 16 years. Although it useful for teaching the fundamentals of burn care, the course is designed for a civilian audience, covers only the first 24 hours of burn care, and presumes the availability of a burn center for patient transfer. In preparation for hostilities in Iraq, we developed several add-on modules to the standard Advanced Burn Life Support course to meet specific needs of military audiences.

View Article and Find Full Text PDF

Purpose: To define clinically useful markers for determining the adequacy of resuscitation after hemorrhage.

Design: Prospective study of 20 Yorkshire swine, using an established model for hemorrhagic shock in swine.

Background And Methods: Clinically useful markers for assessing the adequacy of resuscitation after hemorrhage do not exist.

View Article and Find Full Text PDF

When brain injury accompanies hemorrhage, resuscitation with hypertonic saline (HS) improves intracranial pressure (ICP) and elastance; however, its effect on brain function after a traumatic or ischemic insult has not been assessed. This study compares the electrophysiologic response to hemorrhage and resuscitation with 7.5% NaCl + 6% dextran (HSD), 6% hetastarch (HE), or 0.

View Article and Find Full Text PDF

Hemorrhagic shock and closed head injury often accompany severe trauma. Hypertonic saline may be beneficial in these patients, but few have examined its properties when sufficient volume is infused to achieve sustained resuscitation. Solutions of 6% NaCl (HS), 0.

View Article and Find Full Text PDF