Biomedical subjects

F Snel

Publications and source records attributed to F Snel.

3 recordsLinked to original sources

PubMed2001

Overexpression of components of the Frizzled-Dishevelled cascade results in apoptotic cell death, mediated by beta-catenin.

Frizzled (fz) functions as a 7-transmembrane receptor in the Frizzled-Dishevelled signal transduction cascade. It is involved in architectural control of development in species as divergent as Drosophila and vertebrates. Regulation of multicellular architecture requires control of cell alignment, but also involves an equilibrium among cell proliferation, differentiation, and apoptosis. Recently, modulation of the Frizzled-Dishevelled (Dvl) cascade has been related to apoptosis. However, the role of beta-catenin, a second messenger in the Frizzled-Dishevelled cascade, in programmed cell death is a matter of debate. To elucidate the role of this cascade in apoptosis, we studied the effect of overexpression of fz1, fz2, dvl1, and beta-catenin. The signal transduction pathway and the involvement of beta-catenin were further investigated by using different inhibitors. These experiments were performed in different cell types: COS7, 293, and PC12. Overexpression of fz1, fz2, and dvl1 induced apoptosis in COS7 and 293 cells. beta-Catenin appears to be the mediator for this process since beta-catenin overexpression as well as lithium and valproate induced apoptosis. In contrast, lithium treatment did not result in apoptosis in PC12 cells. We conclude that different components of the Frizzled-Dishevelled cascade can induce apoptosis, but that this effect is dependent on the cell type.

Adaptor Proteins, Signal Transducing↗

PubMed1996

Laryngeal framework surgery for voice improvement.

Dysphonias resulting from incomplete glottis closure or inadequate vocal fold tension are eligible for phonosurgical correction. Many different phonosurgical techniques have been used for these indications, but the disadvantages associated with augmentation of the vocal folds by means of intracordal injections and the favourable reports concerning laryngeal framework surgery, have lead to a change in treatment policy in many centers. Most phonosurgeons presently advocate laryngeal framework surgery as the first treatment of choice. For correction of incomplete glottis closure usually thyroplasty type 1 and arytenoid adduction techniques are used. For correction of vocal fold tension cricothyroid approximation and thyroplasty type 3 can be used. Often combinations of different techniques are required to achieve the best result. It is therefore essential to perform these procedures under local anaesthesia, so that the voice can be monitored during the surgery and so that the surgery can be tailored to the patient's voice, 119 patients underwent laryngeal framework surgery, 85 of them for correction of incomplete glottis closure, which in 75 patients was due to unilateral vocal fold immobility. The results in this group were good also in long term follow-up. Complications were few and insignificant. For 30 patients, mostly transsexuals, the aim of surgery was to obtain a higher vocal pitch. This was successful in most patients, but 4 patients had cartilage fracture at the time of surgery as a result of the extreme cricothyroid approximation required. In all cases adequate repair could be obtained without further sequellae.

Glottis↗

PubMed1984

Isolation and characterization of C-reactive protein from the dog.

Using calcium-dependent affinity chromatography on Sepharose-bearing, covalently-coupled pneumococcal C-polysaccharide, a protein was isolated from the serum of dogs that had undergone general anaesthesia and major surgery. This protein was confirmed as the canine analogue of C-reactive protein (CRP) in other species by virtue of its electron microscopic appearance, subunit composition and behaviour as an acute phase reactant. Dog CRP had an apparent molecular weight of approximately 100,000 and was composed of five subunits of approximately 20,000 MW each. Two of the five subunits in each molecule were glycosylated. Negatively stained preparations had the typical cyclic pentameric disc-like structure of proteins of the pentraxin family, and in some preparations had a tendency to form stacks. Serum from normal healthy dogs of various strains usually contained less than 5 mg/l of CRP but, following the stimulus of major surgery, an increase in the CRP concentration was first detected at 4 hr.

Animals↗