Biomedical subjects

T Wessels

Publications and source records attributed to T Wessels.

4 recordsLinked to original sources

PubMed2003

[Isolated cranial nerve palsy secondary to carotid dissection].

Cranial nerve palsy has a variety of causes such as cerebral ischemia, nerve ischemia in diabetes, infectious and noninfectious meningitis, subarachnoid hemorrhage, malignant tumors of the skull base, neck, or upper mediastinum, aortic aneurysm, surgery of the thyroid,and many more. We report two cases of spontaneous carotid dissections leading to cranial nerve palsies, which is an uncommon cause of isolated cranial nerve palsies.ICA dissection must therefore be included in the differential diagnosis of lower cranial nerve palsy and should be assessed by duplex ultrasound and MRI as is demonstrated in our cases.

Adult↗

PubMed2002

[Von Hippel-Lindau syndrome with spinal, cerebellar, and retinal hemangioblastoma in identical twins].

We report about a case of a 22-year-old women who was admitted because of sudden and painless proximal paraparesis, sensory loss at distal L 1, and bladder dysfunction. In MRI, cystic lesions in the spinal cord were identified at C 1,C 6,T 1,T 6,and T 11 as well as in the cerebellum.A tentative diagnosis of spinal hemangioblastomas was confirmed by spinal angiography and postoperative histology of the symptomatic tumor at T11.Furthermore, retinal hemangioblastomas were detected by fluorescence angiography and treated with laser surgery. Based on the clinical findings,we assumed the diagnosis of von Hippel-Lindau syndrome (vHL).Postoperatively, the paraparesis and sensory deficit improved, but the bladder dysfunction persisted. The patient's identical twin was screened for hemangioblastomas, too, and spinal, retinal, and one cerebellar tumor with a nearly identical location pattern were found. There was no evidence for pancreatic, adrenal, or renal involvement in both twins. The twins were investigated for inactivating mechanisms of the vHL germline mutations using single-strand conformational polymorphism (SSCP) and Southern blotting, but none of the known germline mutations were identified. Because the family history is devoid of vHL disease, spontaneous mutation might be causal for the syndrome in our patients.

Adult↗

PubMed1999

Single-crystal-like diffraction data from polycrystalline materials

A method for solving structures from powder diffraction data was developed, and its validity was demonstrated on three complex structures. The method uses a textured sample and exploits the high intensity and parallel nature of synchrotron radiation. In principle, crystal structures as complex as those routinely solved by single-crystal methods can be determined with this approach. For example, the as-synthesized form of the zeolite UTD-1, with 69 nonhydrogen atoms in the asymmetric unit, could be solved directly. With this method, a larger range of structural complexity becomes accessible to scientists interested in the structures of polycrystalline materials that cannot be grown as single crystals.

Journal Article↗

PubMed1994

Evidences for physically different catalytic and regulatory nucleotide binding sites on the chloroplast H(+)-ATPase.

Chloroplast thylakoids which were incubated with pyridoxal-5-phosphate (PLP) in the dark, exhibit a slower ADP-binding curve in the light and lack the rapid initial phase of rebinding of loosely bound nucleotides upon de-energetization. The [14C]NBD binding pattern in subunits of PLP-modified thylakoids is reduced to that one found if ADP was present in the modification step. The [14C]NBD binding pattern in subunits of activated and successive PLP-modified CF1 is reduced to that one found in the latent enzyme. As in the latent (not activated) ATPase Lys beta 359 is modified by PLP, we conclude that this amino acid residue belongs to a regulatory binding site which binds ADP tightly upon de-energetization and releases it upon energetization. In the activated enzyme, however, the modified residue is related to a 9 kDa peptide in beta, which contains the conserved lysine 178. This site is proposed to be a catalytic one.

Adenosine Diphosphate↗