PubMed Health⌕ Search

Biomedical subjects

J Wenker

Publications and source records attributed to J Wenker.

3 recordsLinked to original sources

Cervical spine instability: clearance using dynamic fluoroscopy.

Cle aring the cervical spine in a multiply injured trauma patient is a dilemma because clinical examination for ligamentous instability cannot be performed, and the standard cervical spine series can miss isolated ligamentous injury. Static flexion/extension views are unsafe, as the obtunded patient has no protective reflexes and cannot complain of pain during the exam. This results in a need for prolonged spinal immobilization and its attendant complications. Dynamic fluoroscopy may be useful in the detection of otherwise occult injuries.We performed a prospective study of a cervical spine clearance algorithm incorporating dynamic fluoroscopy with flexion/extension views. Inpatient records over a 3-year period were reviewed. Patient demographic data, results of cervical spine films and fluoroscopic exams, interventions based on positive results, and missed injuries were recorded.One hundred ten patients with normal spine plain films underwent dynamic fluoroscopy with flexion and extension views of the cervical spine. The average Glasgow Coma Score was 9.2 and the average revised Trauma Score was 9.5. Nine patients had evidence of cervical instability on exam. Six of these were deemed stable by the orthopedic or neurosurgical spine consultants, and these patients had their hard collars removed. One patient with positive findings had cervical immobilization with hard collar continued, a second had halo placement, and a third underwent spinal fusion for atlanto-occipital disassociation. No patients undergoing dynamic fluoroscopy were subsequently found to have missed cervical spine injury.With our protocol, 3 patients had significant cervical instability that would have been missed without dynamic fluoroscopy. Given the significant medical and legal ramifications of missed cervical spine injury and the benefits of early removal of cervical collars, more widespread use of dynamic fluoroscopy of the cervical spine is warranted.

Journal Article↗

Transforming growth factor beta 1: three-dimensional structure in solution and comparison with the X-ray structure of transforming growth factor beta 2.

The three-dimensional solution structure of human transforming growth factor beta 1 (TGF-beta 1) has been determined using multinuclear magnetic resonance spectroscopy and a hybrid distance geometry/ simulated annealing algorithm. It represents one of the first examples of a mammalian protein structure that has been solved by isotopic labeling of the protein in a eukaryotic cell line and multinuclear NMR spectroscopy. The solution structure of the 25 kDa disulfide-linked TGF-beta 1 homodimer was calculated from over 3200 distance and dihedral angle restraints. The final ensemble of 33 accepted structures had no NOE or dihedral angle violations greater than 0.30 A and 5.0 degrees, respectively. The RMSD of backbone atoms for the ensemble of 33 structures relative to their mean structure was 1.1 A when all residues were used in the alignment and 0.7 A when loop regions were omitted. The solution structure of TGF-beta 1 follows two independently determined crystal structures of TGF-beta 2 (Daopin et al., 1992, 1993; Schlunegger & Grütter, 1992, 1993), providing the first opportunity to examine structural differences between the two isoforms at the molecular level. Although the structures are very similar, with an RMSD in backbone atom positions of 1.4 A when loop regions are omitted in the alignment and 1.9 A when all residues are considered, there are several notable differences in structure and flexibility which may be related to function. The clearest example of these is in the beta-turn from residues 69-72: the turn type found in the solution structure of TGF-beta 1 falls into the category of type II, whereas that present in the X-ray crystal structure of TGF-beta 2 is more consistent with a type I turn conformation. This may be of functional significance as studies using TGF-beta chimeras and deletion mutants indicate that this portion of the molecule may be important in receptor binding.

Amides↗

Characterization of recombinant soluble human transforming growth factor-beta receptor type II (rhTGF-beta sRII).

Recombinant human transforming growth factor soluble receptor Type II (rhTGF-beta sRII) corresponding to the 159 amino acid extracellular domain of hTGF-beta RII has been expressed in insect cells using the baculovirus expression system or in a mouse myeloma cell line. N-terminal sequence analysis of the purified protein revealed the removal of the 23 amino acid signal peptide. In SDS-PAGE, the rhTGF-beta sRII resolves into multiple bands due to N-linked glycosylation. Recombinant hTGF-beta sRII is a TGF-beta antagonist and will inhibit the biological activities of TGF-beta 1, TGF-beta 3, and TGF-beta 5 on TGF-beta-responsive cell lines, such as murine HT-2 or human TF-1 with an ED50 of approximately 0.3 micrograms/mL. However, hTGF-beta sRII does not inhibit TGF-beta 2 bioactivities in these cell lines, suggesting that hTGF-beta RII has low affinity for TGF-beta 2. Polyclonal antibodies to hTGF-beta sRII have been produced in goats and purified on Protein-G affinity columns. This antibody can inhibit TGF-beta 1,2,3,5-dependent bioactivities on human cell lines such as TF-1. Additionally, this antibody has species cross-reactivity and will also inhibit TGF-beta-dependent bioactivities on murine cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗