We report the first determination of a distance bracket for the high-velocity cloud (HVC) complex C. Combined with previous measurements showing that this cloud has a metallicity of 0.15 times solar, ...these results provide ample evidence that complex C traces the continuing accretion of intergalactic gas falling onto the Milky Way. Accounting for both neutral and ionized hydrogen as well as He, the distance bracket implies a mass of 3-14x10^6 M_sun, and the complex represents a mass inflow of 0.1-0.25 M_sun/yr. We base our distance bracket on the detection of CaII absorption in the spectrum of the blue horizontal branch star SDSS J120404.78+623345.6, in combination with a significant non-detection toward the BHB star BS 16034-0114. These results set a strong distance bracket of 3.7-11.2 kpc on the distance to complex C. A more weakly supported lower limit of 6.7 kpc may be derived from the spectrum of the BHB star BS 16079-0017.
The term histiocytosis X (HX) refers to a spectrum of disorders varying from unifocal eosinophilic granuloma (UEG), multifocal eosinophilic granuloma (MEG), to the Abt-Letterer-Siwe syndrome. In a ...series of 16 patients with different types of HX and skeletal lesions, whole body bone scintigraphy was performed at the time of diagnosis and during follow up. Results were compared with radiographic findings. In patients with MEG with or without extra-skeletal dissemination bone scintigraphy revealed cold spots or hot spots, but half of the lesions were not visualised scintigraphically, resulting in false negative scans. In UEG the lesions were visualised as areas of increased uptake or as a cold spot with increased uptake at its borders. No false negative scans were encountered. The reliability of skeletal scintigraphy in patients with HX seems to depend on the type of the disorder: in UEG bone scintigraphy is a safe procedure. In MEG false negative bone scans have to be expected, and radiography is superior.
Seven cases are presented of recurrent ventricular catheter obstruction, an infrequent but serious problem in the management of hydrocephalus. Plugging of the catheter was caused by detritus rather ...than by choroid plexus. A retrospective analysis of 214 shunt revisions indicated that obstruction both by detritus and by choroid plexus were incidental phenomena in the great majority of the cases - the former type occurring mainly within the first month, the latter between 3 and 6 months after operation. It is suggested that the ultimate cause of recurrent catheter obstruction by detritus may be destruction or ablation of the ependymal lining of the ventricles (e.g. by an inflammatory process), which easily provides debris to the catheter. In 4 of the cases insertion of the catheter into the opposite ventricle prevented further recurrence, when reinsertion into the same ventricle had been ineffective. In one case, with scarcely dilated ventricles, external decompression was helpful. In patients with compartmentalisation of the ventricles (substantiated in one of our patients) one might consider removal of the septa via craniotomy before the insertion of the catheter.
The projection of the pineal gland between the two outer tables of the skull in the AP film has been reconstructed on the basis of the CT print of the head, with and without lateral rotation. In this ...experimental approach it is proven that rotation up to 5 degrees does not influence the position of the pineal gland on the AP film. The range of the normal position of the pineal in the frontal plane is defined and the normal distribution is given.
Thirty-one patients with isthmic spondylolisthesis were investigated using MR imaging. Twenty-one of these patients had selectively unilateral sciatica and no abnormalities on adjacent discs. In 18 ...patients there was a clear correlation between the degree of foraminal stenosis and the symptomatic side. In 20 patients there was evidence of root compression by disc tissue.
