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Biomedical subjects

G Vogl

Publications and source records attributed to G Vogl.

At least 19 recordsLinked to original sources
PubMed2005

Angiogenic potential of ductal carcinoma in situ (DCIS) of human breast.

AIMS: Comedo carcinoma is generally regarded as the subtype of ductal carcinoma in situ (DCIS) most likely to progress to invasive carcinoma. Increased angiogenesis could be associated with an enhanced risk of progression and might therefore be a marker of poor prognosis, as can be demonstrated for invasive breast tumours. Therefore, the present study investigates the correlations between the expression of oncoproteins (HER2, HER1/EGFR), angiogenic growth factors (VEGF and PD-ECGF/TP) and microvessel density (MVD) in DCIS. METHODS AND RESULTS: Forty-six breast cancer specimens of DCIS were tested immunohistochemically for the expression of angiogenic factors and oncoproteins. Different vascular distribution patterns of DCIS were examined semiquantitatively. Our results showed a significantly inverse correlation between HER1/EGFR and comedo-type DCIS (P = 0.048), but HER1/EGFR expression seemed to be independent of HER2 overexpression. VEGF expression was significantly associated with endoglin expression (P = 0.031) and the cuffing phenomenon (P = 0.017). CONCLUSIONS: The significantly inverse correlation between HER1/EGFR and comedo-type DCIS and the observation that VEGF and the other angiogenic factors tested are independent of HER2 overexpression, suggest that progression of comedo-type DCIS and angiogenesis in breast carcinoma are not regulated via the HER1/EGFR or HER2 pathway.

Adult↗
PubMed2001

Probing jump diffusion in crystalline solids with neutron spin-echo spectroscopy.

Neutron spin-echo spectroscopy has been applied to jump diffusion in a crystalline solid. Definite advantages of spin-echo spectroscopy over quasielastic neutron scattering are the direct visual discrimination of fast and slow diffusion processes and the high resolution in the time-energy domain. The potential of the method is demonstrated by way of Ni diffusion in the intermetallic alloy NiGa.

Journal Article↗
PubMed1999

Heme-solvent coupling: a Mössbauer study of myoglobin in sucrose.

The Mössbauer effect of 57Fe-enriched samples was used to investigate the coupling of 80% sucrose/water, a protein-stabilizing solvent, to vibrational and diffusive modes of the heme iron of CO-myoglobin. For comparison we also determined the Mössbauer spectra of K4 57Fe (CN)6 (potassium ferrocyanide, PFC), where the iron is fully exposed in the same solvent. The temperature dependence of the Mössbauer parameters derived for the two samples proved to be remarkably similar, indicative of a strong coupling of the main heme displacements to the viscoelastic relaxation of the solvent. We show that CO escape out of the heme pocket couples to the same type of fluctuations, whereas intramolecular bond formation involves solvent-decoupled heme deformation modes that are less prominent in the Mössbauer spectrum. With respect to other solvents, however, sucrose shows a reduced viscosity effect on heme displacements and the kinetics of ligand binding due to preferential hydration of the protein. This result confirms thermodynamic predictions of the stabilizing action of sucrose by a dynamic method.

Animals↗
PubMed1993

Subarachnoid hemorrhage as presenting feature of isolated neurosarcoidosis.

A 35-year-old man presented with the clinical picture of spontaneous subarachnoid hemorrhage. Four weeks after the first symptoms he noticed blurred vision, and ophthalmological examination detected bitemporal hemianopia. At this time cerebral computed tomography and magnetic resonance imaging showed enlargement of the optic chiasm, and visual evoked potentials revealed delayed latencies. In the cerebrospinal fluid cells and protein content were elevated, and angiotensin-converting enzyme was detectable. Under steroid treatment the patient recovered completely and computed tomography, magnetic resonance imaging, visual evoked potentials, and cerebrospinal fluid findings became normal. Although a great variety of neurological symptoms may occur in neurosarcoidosis, to our knowledge spontaneous subarachnoid hemorrhage as the presenting feature has never been reported before.

Adult↗
PubMed1992

Mineral crystals in calcified tissues: a comparative study by SAXS.

The shape, the typical orientation, and the average size of mineral crystals in different types of mineralized tissues were investigated by means of small-angle x-ray scattering (SAXS). To rule out eventual artifacts due to sample preparation, four different standard preparation techniques were used and a comparison showed that the SAXS results were identical for all four methods. In mineralized turkey leg tendon, a frequently used model system for bone, the crystals were found to be typically plate-like with a thickness of the order of 2 nm. This stands in contrast to the case of bone (calvaria, femur, and iliac crest) from mouse, rat, and dog, where mainly needle-like crystals were found. The thickness of these crystals ranged from 3 to 4 nm but was remarkably constant for different bones of a given animal. The preferred orientation of the needle-like crystals was along the main axis of the femur and within the surface of the calvaria (for mouse, rat, and dog). The mineral plates in turkey leg tendon were located inside the hole zone and oriented along the fibril axis. Finally, no periodic arrangement of the crystals inside the hole zone of the collagen could be found.

Animals↗
PubMed1992

[The CT-controlled treatment possibilities in intervertebral disk prolapses].

A CT-controlled method for the treatment of lumbar and cervical disc prolapse is described. Compared with fluoroscopically controlled percutaneous lumbar discectomy, percutaneous treatment of the L5/S1 disc by a dorsal approach is possible even in the presence of high iliac crests, as is described in this paper. In the cervical region the risk of iatrogenic damage is reduced. In a small group of 42 patients, an attempt has been made to remove disc material which is intraforaminal, intraspinal, subligamentous or sequestered. Amongst 79 patients with lumbar and 15 patients with cervical disc prolapse treatment was successful in 85% (after 17 months of observation) and 93% (after 12 months of observation). These figures refer to the early results from a new method. The success of the method will have to be assessed after a larger number of patients has been treated and there has been a longer period of observation.

Adult↗
PubMed1992

[Regression of motor symptoms after intervertebral disk displacement-induced spinal nerve root lesion. Clinical study].

Ever since the causal relationship between backache, radicular pain and intravertebral disc herniation was established [25], there have been different opinions about the degree of recovery of motor lesions of the nerve root caused by disc herniation. Of 123 patients with a severe motor deficit of the L5 nerve root, 95 patients were available for a follow up examination 4 to 8 years after the operation. The statistical evaluation showed that the degree of recovery of the root lesion was mainly dependent on the age of the patient and the time interval until operation. Even a prior herniation of the disc without much compression of the nerve root can cause chronic damage to the nerve through traction at the trilamellar nerve root fixation. So even in the case of only a small disc hernia with a corresponding nerve root lesion, we would recommend immediate operative therapy.

Adult↗
PubMed1992

[Neuroradiologic treatment possibilities of intervertebral disk displacement].

A CT assisted method for automated percutaneous lumbar discectomy (APLD) is described. With this technique and introduction of a "pull and push" method as well extruded and sequestrated herniated lumbar discs as cervical herniated discs can be treated. The CT assisted discectomy was performed in 70 patients. The success rate was 86% in the lumbar region and 93% for cervical herniated discs. We believe that this percutaneous technique will increase the importance of interventional neuroradiology for this common disease.

Adult↗
PubMed1991

Nucleation and growth of mineral crystals in bone studied by small-angle X-ray scattering.

The mechanism of calcification in bone and related tissues is a matter of current interest. The mean size and the arrangement of the mineral crystals are important parameters difficult to obtain by electron microscopy. Furthermore, most studies have been carried out on poorly calcified model systems or chemically treated samples. In the work presented here, native bone was studied as a function of age by a quantitative small-angle X-ray scattering method (SAXS). Bone samples (calvariae and ulnae) from rats and mice were investigated. Measurements were performed on native bone immediately after dissection for samples up to 1 mm thick. The size, shape, and predominant orientation of the mineral crystals in bone were obtained for embryonal, young, and adult animals. The results indicate that the mineral nucleates as thin layers of calcium phosphate within the hole zone of the collagen fibrils. The mineral nuclei subsequently grow in thickness to about 3 nm, which corresponds to maximum space available in these holes.

Animals↗
PubMed1991

[Increasing value of the duplex scan in preoperative diagnosis of the carotid artery--is preoperative carotid angiography still sensible?].

In effort to eliminate morbidity and costs, associated with arteriographic investigation, we increasingly perform Duplex Scan of the extracranial carotid artery prior to endarterectomy. 451 carotid reconstructions between 1986 and April 1991 were evaluated retrospectively. The percentage of patients undergoing carotid endarterectomy without angiography has increased from 21.1% to 92.8%. Angiography was associated with a combined neurologic morbidity rate of 3.0%. Perioperative outcome of patients and stratification by indication did not show any significant differences for both groups undergoing Duplex Scan alone and/or angiography. Diagnostic Carotid angiography should only be used selectively in patients showing distal internal carotid plaque, recurrent stenosis, symptomatic carotid occlusion or aortic arch disease.

Aged↗