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J Willeit F Aichner S Felber K Berek F Deisenhammer S G Kiechl F Gerstenbrand 《Journal of the neurological sciences》1992,111(1):20-25
We present 3 cases and a review of the literature to demonstrate the current state of clinical diagnosis and therapy of superficial siderosis of the central nervous system. Typical symptoms were progressive cerebellar ataxia, spasticity and hearing loss. Repeated subarachnoid hemorrhage was indicated by persistent xanthochromia of the cerebrospinal fluid and confirmed by the presence of erythrophages, siderophages and iron-containing pigments. Deposition of free iron and hemosiderin in pial and subpial structures leads to intoxication of the central nervous system and represents the pathophysiological mechanism of superficial siderosis. Hypointensity of the marginal zones of the central nervous system on T2 weighted MR images indicates an iron-induced susceptibility effect and seems pathognomonic for superficial siderosis. In 39 of the 43 previously described cases superficial siderosis was verified by biopsy or autopsy. Today magnetic resonance imaging enables diagnosis at an early stage of the disease. Therapeutic management requires the elimination of any potential source of bleeding. In patients with unknown etiology no proofed therapy is yet available. 相似文献
5.
C P Felley H Kleiber G D van Melle P Frascarolo E Jéquier J P Felber 《International journal of obesity (2005)》1992,16(3):185-191
The present study was designed to assess the respective effect of altered lipid metabolism and hyperglycemia on glucose metabolism in vivo in obese subjects. Six young obese non-diabetic volunteers were studied on four occasions during hyperinsulinemic clamp, twice during euglycemia and twice during hyperglycemia, with or without the infusion of beta-pyridylcarbinol, an inhibitor of lipid metabolism. Glucose oxidation was calculated from continuous respiratory exchange measurements, and glucose storage was obtained as the difference between total glucose disposal and glucose oxidation. Two-way analysis of variance (with interaction term) demonstrated (i) a significant increase for total glucose disposal with beta-pyridylcarbinol but no significant effect of hyperglycemia and no interaction between the two treatments, and (ii) an important increase of beta-pyridylcarbinol to enhance glucose storage but no significant effect of hyperglycemia and no interaction between the two treatments. These results show that obese people, at physiological insulinemia, enhance their glucose disposal and glucose storage when lipid oxidation is artificially lowered. This suggests that enhanced lipid oxidation is related to insulin resistance in these patients. However, hyperglycemia in these patients failed to compensate for defective glucose disposal or storage. 相似文献
6.
Calarota SA Otero M Hermanstyne K Hermanstayne K Lewis M Rosati M Felber BK Pavlakis GN Boyer JD Weiner DB 《Journal of immunological methods》2003,279(1-2):55-67
The enzyme-linked immune spot (ELISPOT) assay is receiving increased attention as a means for quantifying antigen-specific CD8 T-cell responses in rhesus macaques. Further improving the sensitivity of this assay could aid in the evaluation of vaccine candidates and/or immune therapeutic candidates. Interleukin (IL)-15 has been demonstrated to stimulate expansion of human immunodeficiency virus (HIV)-specific cytotoxic T lymphocytes (CTL) and to regulate homeostatic proliferation of CD8+ memory cells. We evaluated the in vitro effect of IL-15 to increase the detection of interferon-gamma (IFN-gamma) production by antigen-specific stimulated lymphocytes from a group of rhesus macaques exposed to simian-human immunodeficiency virus (SHIV) and a second group infected with SIVmac251, before and after antiretroviral treatment (ART). Results from these studies demonstrate that the presence of IL-15 during stimulation in a peptide-based ELISPOT assay greatly enhanced IFN-gamma production in both SHIV and simian immunodeficiency virus (SIV)-infected macaques. IFN-gamma production was mainly mediated by CD8 lymphocytes. The optimal concentrations of IL-15 that give enhancement of IFN-gamma production to specific antigen, without a significant increase in the spontaneous IFN-gamma release, ranged from 0.5 to 2.5 ng/ml. The mean number of IFN-gamma spots was increased 3.1- to 3.6-fold in response to SIV gag or HIV env peptide pools, respectively, in peripheral blood mononuclear cells (PBMC) from SHIV-infected macaques. Similarly, in SIV-infected macaques, IL-15 increased the mean number of IFN-gamma spots 2.7-fold in response to both SIV gag and env peptide pools. In samples obtained after ART in the same macaques, the increase factor was 2.5 for SIV gag and 1.8 for the env peptide pools. Thus, the sensitivity of the ELISPOT assay can be enhanced by addition of IL-15. This modified assay will be useful for detection of low frequencies of IFN-gamma producing cells in rhesus macaques. 相似文献
7.
Christian Baumgartner Ph.D. Kurt Gautsch M.D. Christian Böhm Ph.D. Stephan Felber M.D. 《Journal of digital imaging》2005,18(3):219-226
CT perfusion imaging constitutes an important contribution to the early diagnosis of acute stroke. Cerebral blood flow (CBF), cerebral blood volume (CBV) and time-to-peak (TTP) maps are used to estimate the severity of cerebral damage after acute ischemia. We introduce functional cluster analysis as a new tool to evaluate CT perfusion in order to identify normal brain, ischemic tissue and large vessels. CBF, CBV and TTP maps represent the basis for cluster analysis applying a partitioning (k-means) and density-based (density-based spatial clustering of applications with noise, DBSCAN) paradigm. In patients with transient ischemic attack and stroke, cluster analysis identified brain areas with distinct hemodynamic properties (gray and white matter) and segmented territorial ischemia. CBF, CBV and TTP values of each detected cluster were displayed. Our preliminary results indicate that functional cluster analysis of CT perfusion maps may become a helpful tool for the interpretation of perfusion maps and provide a rapid means for the segmentation of ischemic tissue. 相似文献
8.
Canfield MC; Tamarappoo BK; Moses AM; Verkman AS; Holtzman EJ 《Human molecular genetics》1997,6(11):1865-1871
Congenital nephrogenic diabetes insipidus (NDI) is a rare disease caused
most often by mutations in the vasopressin V2 receptor (AVPR2). We studied
a family which included a female patient with NDI with symptoms dating from
infancy. The patient responded to large doses of desmopressin (dDAVP) which
decreased urine volume from 10 to 4 I/day. Neither the parents nor the
three sisters were polyuric. The patient was found to be a compound
heterozygote for two novel recessive point mutations in the aquaporin-2
(AQP2) gene: L22V in exon 1 and C181W in exon 3. Residue Cys181 in AQP2 is
the site for inhibition of water permeation by mercurial compounds and is
located near to the NPA motif conserved in all aquaporins. Osmotic water
permeability (Pf) in Xenopus oocytes injected with cRNA encoding C181W-AQP2
was not increased over water control, while expression of L22V cRNA
increased the Pf to approximately 60% of that for wild-type AQP2.
Co-injection of the mutant cRNAs with the wild-type cRNA did not affect the
function of the wild-type AQP2. Immunolocalization of AQP2-transfected CHO
cells showed that the C181W mutant had an endoplasmic reticulum-like
intracellular distribution, whereas L22V and wild-type AQP2 showed endosome
and plasma membrane staining. Water permeability assays showed a high Pf in
cells expressing wild-type and L22V AQP2. This study indicates that AQP2
mutations can confer partially responsive NDI.
相似文献
9.
Valentino Constantinou Ashley E. Felber Jennifer L. Chan 《Journal of medical engineering & technology》2017,41(7):534-540
Emerging opportunities to measure individual and population-level health data with activity monitors during recreational running activities may set the stage for new research possibilities in mass participation running events and marathon medicine. This study explores the applicability of consumer activity monitor data in a preliminary study for future marathon health research with a cohort of 12 (n?=?12) participants completing a 3.379?km walking or running course. This study explored the feasibility of collecting pace and distance data from Fitbit brand consumer activity monitors, from access to user data to reporting of data characteristics and data analysis. We show that a large percentage of participant data can be successfully retrieved from Fitbit consumer activity monitor devices for analysis in marathon health research, and that identifying variations in pace across participants is a practical possibility. We note a mean absolute percentage error of 13% over the true distance of 3.379?km, a higher error than that reported by other studies. We also observe a Pearson correlation coefficient between participant variation in pace and absolute distance error of 0.61. This study provides preliminary evidence to support the applicability of consumer activity monitor data in marathon health research. 相似文献
10.
J. Rousselle A. Bückert P. Pahud E. Jéquier J.P. Felber 《Metabolism: clinical and experimental》1982,31(9):866-870
The study was performed to determine the influence of peripheral glucose utilization on glucose tolerance. Glucose oxidation was measured in a group of 6 normal subjects by means of continuous indirect calorimetry during a 100 g oral glucose tolerance test for 3 hr, comparing the control state with experimental inhibition or stimulation of glucose oxidation. Suprabasal oxidation, corresponding to oxidation in response to the load, mainly by insulin-dependent tissue, was obtained by subtracting basal oxidation (essentially by non-insulin dependent tissues) from total oxidation. Suprabasal oxidation of glucose was inhibited by a neutral fat infusion, and stimulated by means of dichloracetate. In the control test, from the 100 g glucose administered, 18 g participated to suprabasal oxidation during the 3 hr of the test. A neutral fat infusion, started 2 hr before the glucose load and lasting throughout the test, decreased suprabasal oxidation to 7.5 g, i.e. to 42% of the control value. With the fat infusion, a larger fraction of the energy consumption was shown to originate from lipid oxidation (37% versus 25% in controls, p < 0.05) at the expense of carbohydrate (CHO) oxidation (44% versus 60% in controls, p < 0.05). However, these major changes in peripheral glucose oxidation were accompanied by only a moderate decrease in glucose tolerance. Dichloracetate administered prior to the test increased suprabasal oxidation to 25 g glucose oxidized in the 3 hours following the glucose load, i.e. an increment of 39% above the control value. A larger fraction of energy consumption was derived from carbohydrates (77% versus 60% in controls, p < 0.05). However, no significant change was observed in glucose tolerance. These results indicate that marked changes of peripheral glucose oxidation have little influence on glucose tolerance and suggest that another mechanism, i.e. glucose storage, plays a larger role in regulating plasma glucose levels during oral glucose tolerance tests. 相似文献