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31.
The complete form of the pli de passage fronto-pariétal moyen of Broca, a gyrus connecting the pre- and postcentral gyri at the level of the presumable primary motor (M1) hand area, represents a rare anatomic variation. By using functional MR imaging in a healthy subject incidentally found to harbor this configuration, we attempted to determine whether such an accessory gyrus would be functionally active and what effect it has on the complex somatotopic within-arm organization of M1. We found a specific and consistent activation pattern along the lateral and medial cortical boundaries of the pli de passage fronto-pariétal moyen. The gyrus completely segregated the M1 finger from the M1 elbow representation, one being laterally and the other medially located. Furthermore the M1 wrist representation was consistently split by the pli de passage fronto-pariétal moyen into a medial and lateral activation cluster. These findings demonstrate that this accessory gyrus not only contains functionally active neurons, but also leads to a functional separation of the motor homunculus at the level of the M1 wrist representation. This is a remarkable finding, because the region of within-arm representations in M1 was previously thought to be necessarily organized in a complex and intermingled fashion, without a topographic segregation between single body parts. 相似文献
32.
33.
BACKGROUND/AIMS: The accuracy and reliability of any method to assess the UVA protection effectiveness of sunscreens needs to be demonstrated. The aim of the present study was to calibrate the effectiveness of a biological end point (Persistent Pigment Darkening, PPD) to assess UVA photoprotection, METHODS: Persistent Pigment Darkening was selected as the end point because its action spectrum extends across the UVA. A broad UVA source was chosen to challenge all UVA wavelengths. Attenuation of UVA was performed with neutral density filters (equally absorbing at all wavelengths). Human subjects were tested with a series of UVA beams attenuated by the neutral density filters. The UVA protection effectiveness of a standard sunscreen was also tested with four panels of volunteers to assess the reproducibility of the method. RESULTS: The attenuation factors of the neutral density filters were found to correspond to the UVA protection factors arrived at with PPD as the end point. The repetitive tests showed a good internal consistency of the method. CONCLUSIONS: The calibration procedure proposed shows threshold PPD, used as an end point in a UVA-PF test method, to be a reliable endogenous dosimeter for UVA radiation that enters the skin. 相似文献
34.
Chris Tsopelas Max Bellon Elaine Bevington James Kollias Sabah Shibli Barry E. Chatterton 《Annals of nuclear medicine》2008,22(9):777-785
Objective
99mTc-Evans Blue (EB) is an agent that contains both radioactive and color signals in a single dose. Earlier studies in animal
models have suggested that this agent when compared with the dual-injection technique of radiocolloid/blue dye can successfully
discriminate the sentinel lymph node. The aim of this study was to investigate the potential of 99mTc-EB as an agent to map the lymphatic system in an ovine model.
Methods Doses of 99mTc-EB (23 MBq) containing EB dye (4 mg) were administered intradermally to the limbs of four anesthetized sheep, and they
were then imaged over 20–30 min using a gamma camera. The study protocol was repeated using 99mTc-antimony trisulfide colloid (ATC) and Patent Blue V dye. The lymph nodes (popliteal, inguinal, and iliac for hind limbs
or prescapular for fore limbs) were identified with a gamma probe during the operative exposure, then dissected and counted
in a large volume counter.
Results Simple and complex (dual) drainage patterns were visible on the scans, and the sentinel node was more radioactive than higher
tier nodes in a chain, for both radiotracers. For 99mTc-EB, maximum radioactive uptake was achieved at 3–6 min for popliteal lymph nodes, 12–14 min for iliac nodes, and 13–14
min for prescapular nodes. 99mTc-ATC resulted in maximum radioactive uptake at 4–6 min for popliteal lymph nodes, 13 min for an inguinal node, 13–20 min
for iliac nodes, and 18 min for a prescapular node. Following 99mTc-EB injection, 15/15 lymph nodes harvested were all radioactive and blue. For 99mTc-radiocolloid/Patent Blue V injection, 8/14 nodes were radioactive and blue, and 6/14 nodes were radioactive only.
Conclusions The soluble radiotracer 99mTc-EB appeared to be a useful lymphoscintigraphic agent in sheep, in which radioactive counts from superficial lymphatic channels
and lymph nodes were sufficient for planar imaging. In comparison with 99mTc-antimony trisulfide colloid, both tracers discriminated the sentinel lymph node up to 50 min after administration; however,
99mTc-EB had the advantage of providing radioactive (gamma probe) and color signals simultaneously during the operative exposure. 相似文献
35.
36.
D. H. Benninger S. Thees S. S. Kollias C. L. Bassetti D. Waldvogel 《Journal of neurology》2009,256(2):256-263
Background
Rest tremor is a hallmark of Parkinson’s disease (PD), but its pathogenesis remains incompletely understood. Nigro-striatal
dopamine deficiency correlates best with bradykinesia, but not with tremor. Oscillating neurons in one or multiple localizations
within the basal gangliathalamo-cortical loop may cause rest tremor, and an active contribution of the cerebellum and the
cerebello-thalamo-cortical projections has been postulated.
Objective
To compare the pattern of grey matter volume in PD patients with and without tremor to identify structural correlates of rest
tremor.
Methods
Voxel-based morphometry (VBM) of a high-resolution 3 Tesla, T1-weighted MR images, pre-processed according to an optimized
protocol using SPM2, was performed in 24 patients with mild to moderate PD comparing local grey matter volume in patients
with (n = 14) and without rest tremor (n = 10).
Results
Grey matter volume is decreased in the right quadrangular lobe and declive of the cerebellum in PD with tremor compared to
those without (PFDR < 0.05).
Conclusions
These results demonstrate for the first time morphological changes in the cerebellum in PD patients with rest tremor and highlight
the involvement of the cerebellum and cerebello- thalamo-cortical circuit in the pathogenesis of parkinsonian rest tremor. 相似文献
37.
Biedermann T Kneilling M Mailhammer R Maier K Sander CA Kollias G Kunkel SL Hültner L Röcken M 《The Journal of experimental medicine》2000,192(10):1441-1452
Polymorphonuclear leukocytes (PMNs) characterize the pathology of T cell-mediated autoimmune diseases and delayed-type hypersensitivity reactions (DTHRs) in the skin, joints, and gut, but are absent in T cell-mediated autoimmune diseases of the brain or pancreas. All of these reactions are mediated by interferon gamma-producing type 1 T cells and produce a similar pattern of cytokines. Thus, the cells and mediators responsible for the PMN recruitment into skin, joints, or gut during DTHRs remain unknown. Analyzing hapten-induced DTHRs of the skin, we found that mast cells determine the T cell-dependent PMN recruitment through two mediators, tumor necrosis factor (TNF) and the CXC chemokine macrophage inflammatory protein 2 (MIP-2), the functional analogue of human interleukin 8. Extractable MIP-2 protein was abundant during DTHRs in and around mast cells of wild-type (WT) mice but absent in mast cell-deficient WBB6F(1)-Kit(W)/Kit(W-)(v) (Kit(W)/Kit(W)(-v)) mice. T cell-dependent PMN recruitment was reduced >60% by anti-MIP-2 antibodies and >80% in mast cell-deficient Kit(W)/Kit(W)(-v) mice. Mast cells from WT mice efficiently restored DTHRs and MIP-2-dependent PMN recruitment in Kit(W)/Kit(W)-(v) mice, whereas mast cells from TNF(-/)- mice did not. Thus, mast cell-derived TNF and MIP-2 ultimately determine the pattern of infiltrating cells during T cell-mediated DTHRs. 相似文献
38.
Maratou E Dimitriadis G Kollias A Boutati E Lambadiari V Mitrou P Raptis SA 《European journal of clinical investigation》2007,37(4):282-290
BACKGROUND: In white blood cells (WBC), the increase in glucose utilization is a prominent feature during immune response and this depends on the function of specific glucose transporter (GLUT) isoforms. The objective was to examine the effects of activation by Phorbol 12-myristate 13-acetate (PMA) or lipopolysaccharide (LPS) and insulin on the expression of GLUT isoforms in all subpopulations of WBC. MATERIALS AND METHODS: Blood was withdrawn from 27 healthy subjects. The expression of GLUT1, GLUT3 and GLUT4 on the plasma membrane of resting and activated monocytes, T- and B-lymphocytes and polymorphonuclear cells (PMNs) was determined in the absence and presence of physiological concentrations of insulin, by flow cytometry. RESULTS: GLUT1 did not respond to insulin in either resting or PMA/LPS activated state. In the resting state, monocytes and B-lymphocytes increased the abundance of GLUT3 and GLUT4 on their plasma membrane in response to insulin; in contrast, T-lymphocytes and PMNs were unresponsive to insulin. In the activated state, monocytes, B- and T- lymphocytes increased the expression of all three GLUT isoforms on their plasma membrane, whilst PMNs increased only GLUT1 and GLUT3; in all WBC, insulin augmented the expression of GLUT4 and GLUT3 isoforms in addition to the stimulation provided by the PMA or LPS treatment alone. CONCLUSION: Activation of WBC leads to increased expression of GLUT1, GLUT3 and GLUT4 isoforms on their plasma membrane; this process was further augmented by insulin. During infection, these mechanisms may help to redistribute glucose as a potential source of energy away from peripheral tissues and direct it towards cells that mediate the immune response and are therefore crucial to survival. 相似文献
39.
Lena Alexopoulou Manolis Pasparakis George Kollias 《The Journal of experimental medicine》1998,188(4):745-754
Lymphotoxin (LT)α knockout mice, as well as double LTα/tumor necrosis factor (TNF) knockout mice, show a severe splenic disorganization with nonsegregating T/B cell zones and complete absence of primary B cell follicles, follicular dendritic cell (FDC) networks, and germinal centers. In contrast, as shown previously and confirmed in this study, LTβ-deficient mice show much more conserved T/B cell areas and a reduced but preserved capacity to form germinal centers and FDC networks. We show here that similar to the splenic phenotype of LTβ-deficient mice, complementation of LTα knockout mice with TNF-expressing transgenes leads to a p55 TNF receptor–dependent restoration of B/T cell zone segregation and a partial preservation of primary B cell follicles, FDC networks, and germinal centers. Notably, upon lipopolysaccharide challenge, LTα knockout mice fail to produce physiological levels of TNF both in peritoneal macrophage supernatants and in their serum, indicating a coinciding deficiency in TNF expression. These findings suggest that defective TNF expression contributes to the complex phenotype of the LTα knockout mice, and uncover a predominant role for TNF and its p55 TNF receptor in supporting, even in the absence of LTα, the development and maintenance of splenic B cell follicles, FDC networks, and germinal centers. 相似文献
40.
Hypoxemic reperfusion after 120 mins of intestinal ischemia attenuates the histopathologic and inflammatory response 总被引:1,自引:0,他引:1
Douzinas EE Kollias S Tiniakos D Evangelou E Papalois A Rapidis AD Tsoukalas GD Patsouris E Roussos C 《Critical care medicine》2004,32(11):2279-2283
OBJECTIVE: It has been suggested that reactive oxygen species play a pivotal role in the initial organ-tissue injury during reperfusion, eliciting inflammatory reaction and multiple organ failure. It was investigated if hypoxemic reperfusion attenuates tissue injury and inflammatory response. DESIGN: Randomized animal study. SETTING: Medical school laboratory. SUBJECTS: Twenty-five male pigs weighing 25-28 kg. INTERVENTIONS: Pigs were subjected to 120 mins of intestinal ischemia by clamping the superior mesenteric artery. Upon declamping, the animals were randomly assigned to receive either hypoxemic reperfusion (HR group, n = 9) reperfused with a Pao2 = 30-35 or normoxemic reperfusion (control group, n = 16) reperfused with a Pao2 = 100 mm Hg for 120 mins. Fluids without inotropes were given to combat circulatory shock during reperfusion. MEASUREMENTS AND MAIN RESULTS: Portal blood and intestinal and lung biopsies were collected at baseline, end of ischemia, and end of reperfusion. Histopathologic changes were scored, and interleukin-1beta, qualitative Limulus amebocyte, lysate test, and Pao2/Fio2 were measured. Eight of 16 animals of the control group and seven of nine of the HR group survived (p = .22). At the end of reperfusion, the intestinal (p = .004) and lung (p = .028) pathologic scores were lower in the HR group compared with controls. The only significant difference in concentration of interleukin-1beta in the portal blood between the two animal groups occurred 120 mins after reperfusion (p = .006). The number of HR animals with a positive Limulus test was significantly smaller compared with controls at 60 (p = .041) and 120 (p = .07) mins of reperfusion. During the period of ischemia, the Pao2/Fio2 decreased similarly in the control and HR group, whereas after 120 mins of reperfusion the rate was significantly higher in the HR group. CONCLUSIONS: Hypoxemic reperfusion represents an intervention that may attenuate the triggering of multifactorial cascade and organ tissue injury. 相似文献