Prevalence, morphology and biology of renal cell carcinoma in von Hippel-Lindau disease compared to sporadic renal cell carcinoma

PURPOSE: Renal cell carcinoma occurs as a sporadic tumor but may be part of the autosomal dominant von Hippel-Lindau disease, characterized by retinal and central nervous system hemangioblastoma, pheochromocytoma, pancreatic cysts and renal cell carcinoma. We determine the prevalence of von Hippel-Lindau disease in a series of unselected renal cell carcinoma cases by molecular genetic analysis, and compare sporadic to von Hippel-Lindau renal cell carcinoma with respect to morphology and biology. MATERIALS AND METHODS: We established registers comprising 63 subjects with von Hippel-Lindau renal cell carcinoma, belonging to 30 distinct families (register A), and 460 unselected patients operated on for renal cell carcinoma in an 11-year period (register B). Molecular genetic analysis of the von Hippel-Lindau gene was performed for living patients of register A, representing 80% of von Hippel-Lindau families, and register B, 62% living patients, to identify von Hippel-Lindau germline mutations. In addition, register B was evaluated by a questionnaire (95% response) for familial occurrence of von Hippel-Lindau disease. RESULTS: The prevalence of von Hippel-Lindau renal cell carcinoma was 1.6% in 189 consenting unselected renal cell carcinoma patients. Risk factors for occult germline von Hippel-Lindau gene mutations in register B included familial renal cell carcinoma in 3 of 3 patients (100%), multifocal or bilateral renal cell carcinoma in 1 of 10 (10%) and age younger than 50 years at diagnosis in 1 of 33 (3%). Compared to sporadic von Hippel-Lindau renal cell carcinoma was characterized by an occurrence 25 years earlier, association with renal cysts, multifocal and bilateral tumors, cystic organization and low grade histology, and a better 10-year survival (p < 0.001 each). In von Hippel-Lindau disease metastases occurred only in tumors larger than 7 cm. CONCLUSIONS: von Hippel-Lindau differs from sporadic renal cell carcinoma in morphology and biology. Our data provide arguments for planning surgery for von Hippel-Lindau renal cell carcinoma and should stimulate future investigations.     

Magnetic resonance imaging of a mediastinal ependymoma

Ependymomas typically occur in the brain and spinal cord, and represent 5% and 16% of primary intracranial and spinal cord tumors respectively. Ependymomas arising outside the central nervous systems are uncommon and when they do occur are usually seen in the sacrococcygeal region. Other reported sites include the pelvis, spinal nerve roots, and lung. An extraspinal mediastinal ependymoma is a rare occurrence, with only two previously reported cases to our knowledge. In both instances, the lesion arose in the posterior mediastinum, and were imaged with either chest radiographs alone or chest radiographs and computed tomography. In our case, plain radiography was followed by magnetic resonance imaging. This report documents the clinical, pathological, and magnetic resonance imaging findings in a case of a posterior mediastinal ependymoma. Primary mediastinal ependymomas are rare lesions that may be considered in the differential diagnosis of a posterior mediastinal mass.     

Structural and optical properties of heterostructures with InAs quantum dots in an InGaAsN quantum well grown by molecular-beam epitaxy

Results obtained in a study of the structural and optical properties of GaAs-based heterostructures with InAs quantum dot layers overgrown with InGaAsN quantum wells are presented. Transmission electron microscopy has been applied to analyze how the thickness of the InGaAsN layer and the content and distribution of nitrogen in this layer affect the size of nanoinclusions and the nature and density of structural defects. It is shown that the size of InAs nanodomains and the magnitude of the lattice mismatch in structures containing nitrogen exceed those in nitrogen-free structures. A correlation between the luminescence wavelength and the size and composition of nanodomains is demonstrated. Furthermore, a correlation between the emission intensity and defect density in the structure is revealed.     

Zur Feuchtebewegung im Holz während der konvektiven Vakuumtrocknung

This research was conducted to better understand moisture transport in wood during convective vacuum drying. Boards of beech, oak, spruce and scots pine with initial moisture contents of 66%, 92%, 28% and 33%, respectively, were dried under similar conditions in vacuum and at atmospheric pressure. We determined drying times and moisture content distributions, pressures and temperatures in the boards during the whole process. The boards of beech, spruce and scots pine dried approximately three times faster in vacuum than at atmospheric pressure, while the drying times for oak are hardly different. Above 45% moisture content beech and oak dried similarily, thus vacuum only accelerated hygroscopical drying. Pressures measured in beech and oak were always higher than saturation pressures corresponding to simultaneously measured temperatures, although during drying of beech we had boiling conditions in the vessel. We conclude that during vacuum drying air contained in the lumina keeps the pressure up, and water cannot boil as is often supposed. Diffusions coefficients calculated from moisture content gradients in the boards increased significantly at low moisture contents at vacuum drying but not at drying with normal pressures.     

Noradrenaline hyperpolarizes identified rat mesopontine cholinergic neurons in vitro

Inhibition of brainstem cholinergic neurons by noradrenergic neurons of the locus ceruleus has long been suggested as a key mechanism of behavioral state control. In particular, the commonly held view is that noradrenaline (NA) plays a permissive role in rapid eye movement (REM) sleep generation by disinhibiting brainstem cholinergic neurons. While this notion has been supported by numerous investigations, the inhibition of cholinergic neurons by NA has never been directly demonstrated. The purpose of this study was to investigate the effects of NA upon identified cholinergic neurons in the rat mesopontine tegmentum. Using whole-cell patch-clamp recordings in slices, 175 cells were studied during bath application of 50 microM NA. Cholinergic neurons were positively identified by intracellular labeling with biocytin and subsequent staining with NADPH-diaphorase, a reliable marker for brainstem cholinergic neurons (Vincent et al., 1983). Successful intracellular labeling was obtained in 96 cells. Ninety-two percent (36 of 39) of cholinergic neurons hyperpolarized in response to NA, while noncholinergic cells (n = 57) exhibited mixed responses. Application of NA in a low-Ca2+, high-Mg2+ solution elicited the same hyperpolarizing effect as in normal solution, which indicated that the effect of NA on cholinergic neurons was direct. The noradrenergic hyperpolarization was mimicked by the alpha 2-adrenoceptor agonist UK-14,304, and was blocked by the alpha 2-adrenoceptor antagonist idazoxan, which suggested an alpha 2-mediated response. Finally, voltage-clamp experiments revealed that NA activates the inwardly rectifying potassium current, IKG.(ABSTRACT TRUNCATED AT 250 WORDS)     

Simulation of thermochemical and thermomechanical load in blast furnace hearth

All investigations made in the course of the present inquiry aimed at developing proposals for the optimisation of blast furnace bottom and hearth refractories by means of experimental tests. Furthermore, the tests are intended to develop new solutions for prolongation campaign life of blast furnace linings by applying the finite-element method. In the model calculations, particularly those bricks having a high thermal conductivity, showed high resistance to crack and spall formation. In comparison to standard or microporous grades, graphite containing carbon blocks lower the risk of tensile cracks. By additionally doping graphite containing grades with aluminium oxide and silicon, high resistance against pig iron dissolution and infiltration can be reached. Metallurgical coke content proved disadvantageous in the brick, because due to its high porosity the content can be infiltrated additionally into the porous binding matrix. Reduced flow in the brickwork and, thus, reduced convective heat transfer lead to reduced tensile levels in the brickwork. By adapting the pool depth and tap hole length, particularly the linings in the bottom and tap hole area will be relieved thermically. In addition to the required stability of coke particle size and its large particle diameter to ensure an equally distributed pig iron flow through the dead man, the dead man should also have good carburization capacities. When comparing the dissolving inclination by temperature reduction at the internal hearth wall side to the doping influence, it becomes clear that wear can be reduced much more efficiently by adding aluminium oxide than by increasing cooling measures.     

Phase I trial of the thioether phospholipid analogue BM 41.440 in cancer patients

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