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Biomedical subjects

E Elson

Publications and source records attributed to E Elson.

18 recordsLinked to original sources
PubMed2002

De novo GLI3 mutation in acrocallosal syndrome: broadening the phenotypic spectrum of GLI3 defects and overlap with murine models.

Acrocallosal syndrome (ACS) is characterised by postaxial polydactyly, hallux duplication, macrocephaly, and absence of the corpus callosum, usually with severe developmental delay. The condition overlaps with Greig cephalopolysyndactyly syndrome (GCPS), an autosomal dominant disorder that results from mutations in the GLI3 gene. Here we report a child with agenesis of the corpus callosum and severe retardation, both cardinal features of ACS and rare in GCPS, who has a mutation in GLI3. Since others have excluded GLI3 in ACS, we suggest that ACS may represent a heterogeneous group of disorders that, in some cases, may result from a mutation in GLI3 and represent a severe, allelic form of GCPS. The finding is important for counselling families with suspected ACS.

Abnormalities, Multiple↗
PubMed1998

Regulation of cytoskeletal mechanics and cell growth by myosin light chain phosphorylation.

The role of myosin light chain phosphorylation in regulating the mechanical properties of the cytoskeleton was studied in NIH/3T3 fibroblasts expressing a truncated, constitutively active form of smooth muscle myosin light chain kinase (tMK). Cytoskeletal stiffness determined by quantifying the force required to indent the apical surface of adherent cells showed that stiffness was increased twofold in tMK cells compared with control cells expressing the empty plasmid (Neo cells). Cytoskeletal stiffness quantified using magnetic twisting cytometry showed an approximately 1.5-fold increase in stiffness in tMK cells compared with Neo cells. Electronic volume measurements on cells in suspension revealed that tMK cells had a smaller volume and are more resistant to osmotic swelling than Neo cells. tMK cells also have smaller nuclei, and activation of mitogen-activated protein kinase (MAP kinase) and translocation of MAP kinase to the nucleus are slower in tMK cells than in control cells. In tMK cells, there is also less bromodeoxyuridine incorporation, and the doubling time is increased. These data demonstrate that increased myosin light chain phosphorylation correlates with increased cytoskeletal stiffness and suggest that changing the mechanical characteristics of the cytoskeleton alters the intracellular signaling pathways that regulate cell growth and division.

3T3 Cells↗
PubMed1997

Defining the use of gadolinium enhanced MRI in the assessment of the postoperative lumbar spine.

A retrospective study of case notes and magnetic resonance imaging (MRI) examinations was performed to assess the value of gadolinium enhanced MRI in the investigation of persistent back pain following lumbar spine surgery in patients who have not had a discectomy for disc herniation. Gadolinium enhancement is commonly used during MRI of patients with persistent back pain following surgery and epidural scar is frequently identified in patients who have had a previous discectomy. However the value of gadolinium enhancement in patients without previous discectomy had not been addressed. One hundred sets of case notes were examined and 24 patients with an accurate history of previous lumbar spine surgery without discectomy were identified. The nature of surgery and the MRI findings were correlated in these patients. Epidural enhancement was identified at seven sites in six patients (engorged epidural venous plexus, three; enhancement adjacent to degenerate discs, two; enhancement adjacent to facets, two). In no case was epidural scarring involving nerve roots identified. We conclude that routine gadolinium enhancement is unnecessary in patients without a history of discectomy for disc herniation.

Aged↗
PubMed1994

Lipolysaccharide-induced monocyte retention in the lung. Role of monocyte stiffness, actin assembly, and CD18-dependent adherence.

Blood monocytes and monocyte-derived macrophages accumulate in the lungs and can modulate pulmonary inflammatory and reparative processes through their elaboration of cytokines and growth factors. Endotoxemia, often a prelude to acute lung injury, induces a monocytopenia, likely resulting from monocyte accumulation in the lung. We hypothesized that LPS would induce monocyte lung retention by increasing monocyte stiffness and thereby diminishing the cell's ability to deform and transit the narrow pulmonary capillary network, and that LPS would induce CD18-dependent adhesion of monocytes to endothelium, prolonging their retention. LPS induced a rapid and concentration-dependent increase in human monocyte stiffness, net filamentous actin assembly, and retention in a filtration model of pulmonary capillaries. These LPS-induced responses were dependent on the integrity of actin filaments in that cytochalasin D, an agent that disrupts filamentous actin assembly, attenuated each of these processes. LPS induced CD18-dependent and -independent human monocyte adhesion to unstimulated human endothelial cell monolayers. In vivo, rabbit monocytes were retained in the lungs of animals rendered endotoxemic. Pretreatment of monocytes ex vivo with LPS enhanced their lung retention suggesting that LPS was acting directly on monocytes. Initial lung retention during endotoxemia was attenuated by inhibiting monocyte F-actin assembly with cytochalasin D. Anti-CD18 Abs caused a slight decrease in initial retention of monocytes, but led to a 90% inhibition of retention by 2 h. Control IgG had no effect. These data suggest that the initial retention of monocytes in the lung during endotoxemia is dependent on alterations in their stiffness and assembly/organization of F-actin, and that CD18-dependent adhesive mechanisms prolong monocyte retention in the lung during this process.

Actins↗
PubMed1989

Trephine needle bone marrow biopsy in the initial staging of Hodgkin disease: sensitivity and specificity of the Ann Arbor staging procedure criteria.

The purpose of this study was to test the value of the Ann Arbor staging procedures committee criteria in defining a group of newly diagnosed patients with Hodgkin disease who do not have involvement of the bone marrow and do not need this procedure performed. One hundred sixty-six bilateral and 16 unilateral trephine bone marrow biopsies were performed in a consecutive series of 182 patients undergoing initial staging for Hodgkin disease. Bone marrow involvement was found in 13 patients. Advanced stage, defined as stage III or IV, occurring in 92%, anemia occurring in 100%, and "B" symptoms present in 100% were found to be the most sensitive indicators for bone marrow involvement. Osseous disease (99%), platelet count less than 150,000/mm3 (98%), and WBC less than 4,800/mm3 (94%) were the most specific parameters. The known association of bone marrow involvement with older patients, lymphocyte depleted histology, lower blood cell counts, anemia, advanced stage, and poorer survival is verified. The Ann Arbor staging procedures committee criteria for performing a bone marrow biopsy were shown to be 100% sensitive and 40% specific. Use of these criteria would have found all 13 patients with bone marrow involvement. Of the 73 patients who did not meet the criteria, no patient had bone marrow involvement. Use of the Ann Arbor staging procedures committee criteria is recommended.

Adult↗
PubMed1988

Distribution and lateral mobility of voltage-dependent sodium channels in neurons.

Voltage-dependent sodium channels are distributed nonuniformly over the surface of nerve cells and are localized to morphologically distinct regions. Fluorescent neurotoxin probes specific for the voltage-dependent sodium channel stain the axon hillock 5-10 times more intensely than the cell body and show punctate fluorescence confined to the axon hillock which can be compared with the more diffuse and uniform labeling in the cell body. Using fluorescence photobleaching recovery (FPR) we measured the lateral mobility of voltage-dependent sodium channels over specific regions of the neuron. Nearly all sodium channels labeled with specific neurotoxins are free to diffuse within the cell body with lateral diffusion coefficients on the order of 10(-9) cm2/s. In contrast, lateral diffusion of sodium channels in the axon hillock is restricted, apparently in two different ways. Not only do sodium channels in these regions diffuse more slowly (10(-10)-10(-11) cm2/s), but also they are prevented from diffusing between axon hillock and cell body. No regionalization or differential mobilities were observed, however, for either tetramethylrhodamine-phosphatidylethanolamine, a probe of lipid diffusion, or FITC-succinyl concanavalin A, a probe for glycoproteins. During the maturation of the neuron, the plasma membrane differentiates and segregates voltage-dependent sodium channels into local compartments and maintains this localization perhaps either by direct cytoskeletal attachments or by a selective barrier to channel diffusion.

Animals↗
PubMed1976

Mobility measurement by analysis of fluorescence photobleaching recovery kinetics.

Fluorescence photobleaching recovery (FPR) denotes a method for measuring two-dimensional lateral mobility of fluorescent particles, for example, the motion of fluorescently labeled molecules in approximately 10 mum2 regions of a single cell surface. A small spot on the fluorescent surface is photobleached by a brief exposure to an intense focused laser beam, and the subsequent recovery of the fluorescence is monitored by the same, but attenuated, laser beam. Recovery occurs by replenishment of intact fluorophore in the bleached spot by lateral transport from the surrounding surface. We present the theoretical basis and some practical guidelines for simple, rigorous analysis of FPR experiments. Information obtainable from FPR experiments includes: (a) identification of transport process type, i.e. the admixture of random diffusion and uniform directed flow; (b) determination of the absolute mobility coefficient, i.e. the diffusion constant and/or flow velocity; and (c) the fraction of total fluorophore which is mobile. To illustrate the experimental method and to verify the theory for diffusion, we describe some model experiments on aqueous solutions of rhodamine 6G.

Biological Transport↗