In-vitro experiments to estimate the impact of EMI from cellular phone and base-station antennas on implantable cardiac pacemakers

Author(s):  
Y. Tarusawa ◽  
T. Nojima ◽  
T. Toyoshima
Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 2649-2649
Author(s):  
Emmanuel Bachy ◽  
John F. Seymour ◽  
Pierre Feugier ◽  
Fritz Offner ◽  
Dolores Caballero ◽  
...  

Abstract Abstract 2649 Background. Conflicting results have been published to date concerning the impact of statin use on the prognosis of patients with non-Hodgkin lymphoma (NHL) treated with a rituximab-containing first-line regimen. By impairing protein prenylation and possibly lipid-raft formation, statins have been shown to exert an antitumoral activity both on solid and hematological malignancies in vitro as well as in animal models. However, in vitro experiments have demonstrated an unexpected impairment of anti-CD20 antibody binding due to changes in conformational epitopes of the molecule. As a result, statins were found to decrease anti-CD20 induced complement-dependent cytotoxicity and antibody-dependent cellular cytotoxicity. Several groups worldwide attempted to assess the outcome of patients on statins receiving rituximab for NHL. No detrimental effect was observed across studies for patients with diffuse large B-cell lymphoma treated upfront with R-CHOP or R-CHOP-like regimen but a surprising prolonged event-free survival (EFS) was observed for patients with follicular lymphoma (FL) in one study. However, several caveats of the study precluded definitive conclusions to be drawn such as treatment heterogeneity, the enrollment of patients who did not receive rituximab, the retrospective assessment of statin use through medical charts and the consideration of EFS as the primary endpoint without specific evaluation of overall survival (OS). The impact of statin use on the prognosis of patients with FL therefore requires further investigation. Patients and methods. The randomized, open-label PRIMA study enrolled 1217 patients with de novo FL from 223 centers in 25 countries. Patients achieving at least a partial response following frontline therapy with R-CHOP, R-CVP or R-FCM were randomized between 2-years rituximab maintenance (every 8 weeks) or observation. A significant improvement of progression-free survival (PFS) was observed in the rituximab maintenance arm (HR=0.55, 95% CI=0.44–0.68, p<0.0001). All concomitant treatments at enrollment, including the use of statins, were prospectively collected. 1140 patients with complete medication data available at registration were included in this analysis. Among them, 10.4% (n=119) were on statins. Baseline demographic characteristics between patients on statins and those not on statins were compared with the use of a Chi-square test. Various endpoints such as EFS, PFS, OS, time-to-next lymphoma treatment (TTNLT) and time-to-next chemotherapy (TTNCT) were examined in univariate and multivariate analysis. All time-to-event durations were calculated from the date of randomization (6 months after the start of induction therapy). Results. As expected, the use of statins was associated to an older age at registration (P<0.001) and, as a consequence, to a higher FLIPI risk score (P<0.001). Male sex was also overrepresented among statins users, although not significant (P=0.07). Unexpectedly, LDH was more frequently above the upper normal limit (P=0.03). No other difference was observed with regards to demographic data according to statin use. No difference in overall response rate to induction regimen as well as in the quality of the response (CR/Cru versus PR versus others) was noted (P=0.53). No further difference was found at the end of the maintenance period either for patients in the observation or in the rituximab treatment arm. Of note, no imbalance was detected concerning the rate of adverse events between the 2 groups of patients as a whole (grade 1–2 versus 3–4, P=0.18) or with regards to each particular toxicity. Finally, outcome in terms of EFS, PFS (see figure above), OS, TTNLT and TTNCT were similar regardless of the use of statins (P=0.76, P=0.43, P=0.21, P=0.83 and P=0.31 respectively). Importantly, further adjustment for potential confounding factors in multivariate Cox models such as age, FLIPI score or LDH (which were imbalanced between the 2 groups) did not reveal a potential beneficial effect. Conclusion. As for other subtypes of NHL, the use of statins in patients with FL in the rituximab era appeared safe and was not associated with an inferior outcome as suggested by in vitro experiments. Disclosures: No relevant conflicts of interest to declare.


2002 ◽  
pp. 297-304
Author(s):  
Vincenzo Barbaro ◽  
Pietro Bartolini ◽  
Andrea Donato ◽  
Carmelo Militello

Massive Multi-Input and Multi-Output (MIMO) antenna system provides unlimited capacity by the spatial multiplexing and array gain. Since the data rate has been limited by the coherence interference due to pilot contamination (PC). In this paper, we propose transmit combine and precoding schemes to achieve asymptotic capacity in multi-cell scenario, when the number of base station antennas tends to infinity. The impact of spatial channel correlation on channel capacity is explored by considering the co-variance matrices of the user –terminals (UT)s .To do this, we presented linear processing schemes such as MMSE,MRC, and ZF.Where MMSE achieves high capacity in the presence of large-scale fading and PC. Since the diagonals of the channel covariance matrices were designed with non- zero Eigen values and linearly independent. The results outperform and obtain asymptotic limit, when the co-variance of UTs are linearly independent. The results were simulated by using MATLAB 2018b.


1998 ◽  
Vol 53 (3-4) ◽  
pp. 151-158 ◽  
Author(s):  
P. He ◽  
K. P. Bader ◽  
A. Radunz ◽  
U. Kahmann ◽  
G. H. Ruppel ◽  
...  

Abstract Three months old plants of the Chinese tung-oil tree Aleurites montana (Euphorbiaceae) were cultivated for 4 months in air containing 700 ppm CO2. These plants, which grow substantially better in the CO2-enriched atmosphere, were analyzed by mass spectrometry for photosynthesis and photorespiration together with control plants grown all the time in normal (350 ppm CO2) air. Thereafter part of the plants was subjected for two weeks to 0.3 ppm SO2 in the atmosphere and again analyzed for photosynthesis and photorespiration. Aleurites montana exhibits a strongly CO2-dependent photosynthesis which partially explains the observed stimulatory effect of 700 ppm CO2 on growth of the plant. In control plants grown in normal air, photorespiration measured simultaneously with photosynthesis via the uptake of l80 2 in the light, is much lower than in C3-plants like tobacco (H e et al., 1995, Z. Naturforsch. 50c, 781-788 ). In Aleurites grown in 700 ppm CO2, however, photorespiration is completely absent in contrast to tobacco when grown under 700 ppm CO2. In tobacco, photorespiration is not inhibited to the extent of the in vitro experiments in which plants grown at 350 ppm CO2 are measured under the increased CO2 content of 700 ppm. Gas exchange measurements carried out by mass spectrometry show that the ratio of O2 evolved to CO2 fixed is about 0.5. Apparently, part of the CO2 fixed is channelled into a metabolic path without concomitant O2-evolution. Although the plant has no succulent appearance (its leaves somehow resemble maple leaves) apparently a Crassulacean type metabolism is performed. When Aleurites plants grown all the time in normal air with 350 ppm, are exposed for two weeks to 0.3 ppm SO2 the treatment completely inhibits this CO2-fixing portion which is tentatively attributed to a Crassulacean type of metabolism. This is demonstrated by a normal C3-type ratio O2 evolved /CO2 fixed of 1. When Aleurites plants, grown for 4 months in a CO2-enriched atmosphere of 700 ppm CO2, are subjected for two weeks to 0.3 ppm SO2, the features of control plants show up again. When these plants are tested under 350 ppm CO2 the Crassulacean type CO2-fixation apparently is not inhibited by SO2. Photorespiration, although low, is present in the same activity as in the controls. Seemingly, an increased level of CO2 in air tends to alleviate the impact of the SO2 at least in the Chinese tung-oil tree.


2020 ◽  
Author(s):  
Daoyong Li ◽  
Chao Wu ◽  
He Tian ◽  
Liang Mao ◽  
Zhanshan Gao ◽  
...  

Abstract Background:Impaired wound healing is one of the important complications of diabetes. However, the specific pathogenesis is still unclear, and there is no effective treatment. Macrophages pretreated with chemical or biological factors may increase the biological activity of macrophage-derived exosomes, which is expected to become a new effective treatment method. The purpose of this study was to investigate whether the exosomes secreted by macrophages pretreated with lipopolysaccharide (LPS) have better anti-inflammatory and angiogenic abilities in the treatment of diabetic wound healing and their underlying molecular mechanisms.Methods:In this study, macroscopical, biochemical, histological, immunofluorescence and molecular biology methods were used to evaluate the potential protective mechanism and effect of lipopolysaccharide stimulated macrophage exosomes (LPS-Exos) on wound healing in streptozotocin induced hyperglycemia rats.In the in vivo experiment, the percentages of wound closure and contraction were compared and analyzed on the 7th, 14th, and 21st day after treatment by grouping treatments with different concentrations of LPS-Exos.At the same time, hematoxylin and eosin staining (HE), Masson staining, immunofluorescence staining and Western blotting (WB) were used for histological analysis of the wound tissue on the 14th day after injury to evaluate the impact of different treatment methods on wound healing.In in vitro experiments, the ability of endothelial cells related to proliferation, migration, tube formation and the expression of vascular endothelial growth factor (VEGF) were tested.At the same time, in vivo and in vitro experiments, the effect of Nrf2/HO-1 signaling pathway on LPS-Exos in inhibiting inflammation and promoting angiogenesis was evaluated by using exosome-specific inhibitors.Results:LPS-Exos reduced the content of ROS and MDA in the wound tissue of hyperglycemic rats, increased the activity of SOD and the production of GSH-Px, activated the Nrf2/HO-1 pathway, inhibited the expression of inflammation-related proteins, and promoted blood vessels generate. The group given exosome inhibitors reversed this phenomenon.Conclusions: LPS-Exos may activate the Nrf2/HO-1 defense pathway, improve endothelial cell function, inhibit oxidative damage and inflammation, and promote wound healing in diabetic rats, thereby having the potential to treat diabetic skin defects.


2020 ◽  
Author(s):  
Wahbi K. El-Bouri ◽  
Andrew MacGowan ◽  
Tamás I. Józsa ◽  
Matthew J. Gounis ◽  
Stephen J. Payne

1AbstractMany ischaemic stroke patients who have a mechanical removal of their clot (thrombectomy) do not get reperfusion of tissue despite the thrombus being removed. One hypothesis for this ‘no-reperfusion’ phenomenon is micro-emboli fragmenting off the large clot during thrombectomy and occluding smaller blood vessels downstream of the clot location. This is impossible to observe in-vivo and so we here develop an in-silico model based on in-vitro experiments to model the effect of micro-emboli on brain tissue. Through in-vitro experiments we obtain, under a variety of clot consistencies and thrombectomy techniques, micro-emboli distributions post-thrombectomy. Blood flow through the microcirculation is modelled for statistically accurate voxels of brain microvasculature including penetrating arterioles and capillary beds. A novel micro-emboli algorithm, informed by the experimental data, is used to simulate the impact of micro-emboli successively entering the penetrating arterioles and the capillary bed. Scaled-up blood flow parameters – permeability and coupling coefficients – are calculated under various conditions. We find that capillary beds are more susceptible to occlusions than the penetrating arterioles with a 4x greater drop in permeability per volume of vessel occluded. Individual microvascular geometries determine robustness to micro-emboli. Hard clot fragmentation leads to larger micro-emboli and larger drops in blood flow for a given number of micro-emboli. Thrombectomy technique has a large impact on clot fragmentation and hence occlusions in the microvasculature. As such, in-silico modelling of mechanical thrombectomy predicts that clot specific factors, interventional technique, and microvascular geometry strongly influence reperfusion of the brain. Micro-emboli are likely contributory to the phenomenon of no-reperfusion following successful removal of a major clot.2Author summaryAfter an ischaemic stroke - one where a clot blocks a major artery in the brain - patients can undergo a procedure where the clot is removed mechanically with a stent - a thrombectomy. This reopens the blocked vessel, yet some patients don’t achieve blood flow returning to their tissue downstream. One hypothesis for this phenomenon is that the clot fragments into smaller clots (called micro-emboli) which block smaller vessels downstream. However, this can’t be measured in patients due to the inability of clinical imaging resolving the micro-scale. We therefore develop a computational model here, based on experimental thrombectomy data, to quantify the impact of micro-emboli on blood flow in the brain after the removal of a clot. With this model, we found that micro-emboli are a likely contributor to the no-reflow phenomenon after a thrombectomy. Individual blood vessel geometries, clot composition, and thrombectomy technique all impacted the effect of micro-emboli on blood flow and should be taken into consideration to minimise the impact of micro-emboli in the brain. Furthermore, the computational model developed here allows us to now build large-scale models of blood flow in the brain, and hence simulate stroke and the impact of micro-emboli on the entire brain.


2021 ◽  
Vol 17 (3) ◽  
pp. e1008515
Author(s):  
Wahbi K. El-Bouri ◽  
Andrew MacGowan ◽  
Tamás I. Józsa ◽  
Matthew J. Gounis ◽  
Stephen J. Payne

Many ischaemic stroke patients who have a mechanical removal of their clot (thrombectomy) do not get reperfusion of tissue despite the thrombus being removed. One hypothesis for this ‘no-reperfusion’ phenomenon is micro-emboli fragmenting off the large clot during thrombectomy and occluding smaller blood vessels downstream of the clot location. This is impossible to observe in-vivo and so we here develop an in-silico model based on in-vitro experiments to model the effect of micro-emboli on brain tissue. Through in-vitro experiments we obtain, under a variety of clot consistencies and thrombectomy techniques, micro-emboli distributions post-thrombectomy. Blood flow through the microcirculation is modelled for statistically accurate voxels of brain microvasculature including penetrating arterioles and capillary beds. A novel micro-emboli algorithm, informed by the experimental data, is used to simulate the impact of micro-emboli successively entering the penetrating arterioles and the capillary bed. Scaled-up blood flow parameters–permeability and coupling coefficients–are calculated under various conditions. We find that capillary beds are more susceptible to occlusions than the penetrating arterioles with a 4x greater drop in permeability per volume of vessel occluded. Individual microvascular geometries determine robustness to micro-emboli. Hard clot fragmentation leads to larger micro-emboli and larger drops in blood flow for a given number of micro-emboli. Thrombectomy technique has a large impact on clot fragmentation and hence occlusions in the microvasculature. As such, in-silico modelling of mechanical thrombectomy predicts that clot specific factors, interventional technique, and microvascular geometry strongly influence reperfusion of the brain. Micro-emboli are likely contributory to the phenomenon of no-reperfusion following successful removal of a major clot.


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