Effects of hemodialysis therapy on sit-to-walk characteristics in end stage renal disease patients

Patients with end stage renal diseases (ESRD) undergoing hemodialysis (HD) have high morbidity and mortality due to multiple causes; one of which is dramatically higher fall rates than the general population. In spite of the multiple efforts aiming to decrease the high mortality and improve quality of life in ESRD patients, limited success has been achieved. If adequate interventions for fall prevention are to be achieved, the functional and mobility mechanisms consistent with falls in this population must be understood. Human movements such as sit-to-walk (STW) tasks are clinically significant, and analysis of these movements provides a meaningful evaluation of postural and locomotor performance in elderly patients with functional limitations indicative of fall risks. In order to assess the effects of HD therapy on fall risks, 22 sessions of both pre- and post-HD measurements were obtained in six ESRD patients utilizing customized inertial measurement units (IMU). IMU signals were denoised using ensemble empirical mode decomposition and Savistky-Golay filtering methods to detect relevant events for identification of STW phases. The results indicated that patients were slower to get out of the chair (as measured by trunk flexion angular accelerations, time to peak trunk flexion, and overall STW completion time) following the dialysis therapy session. STW is a frequent movement in activities of daily living, and HD therapy may influence the postural and locomotor control of these movements. The analysis of STW movement may assist in not only assessing a patient's physical status, but in identifying HD-related fall risk as well. This preliminary study presents a non-invasive method of kinematic measurement for early detection of increased fall risk in ESRD patients using portable inertial sensors for out-patient monitoring. This can be helpful in understanding the pathogenesis better, and improve awareness in health care providers in targeting interventions to identify individuals at risk for fall

Proteinase-activated receptor-2 modulates human macrophage differentiation andeffector function

Proteinase-activated receptor-2 (PAR-2) was shown to influence immune regulation; however, its role in human macrophage subset development and function has not been addressed. Here, PAR-2 expression and activation was investigated on granulocyte macrophage (GM)-CSF(M1) and macrophage (M)-CSF(M2) macrophages. In both macrophages, the PAR-2-activating peptide, SLIGKV, increased PAR-2 expression and regulated TNF-α and IL-10 secretion in a manner similar to LPS. In addition, HLA-DR on M1 cells also increased. Monocytes matured to an M1 phenotype in the presence of SLIGKV had reduced cell area, and released less TNF-α after LPS challenge compared with vehicle (P < 0.05, n = 3). Cells matured to an M2 phenotype with SLIGKV also had a reduced cell area and made significantly more TNF-α after LPS exposure compared to vehicle (P < 0.05, n = 3) with reduced IL-10 secretion (P < 0.05, n = 3). Thus, PAR-2 activation on macrophage subsets regulates HLA-DR and PAR-2 surface expression, and drives cytokine production. In contrast, PAR-2 activation during M1 or M2 maturation induces altered cell morphology and skewing of phenotype, as evidenced by cytokine secretion. These data suggest a complex role for PAR-2 in macrophage biology and may have implications for macrophage-driven disease in which proteinase-rich environments can influence the immune process directly

Prediction of Leaf Area in Individual Leaves of Cherrybark Oak Seedlings (Quercus pagoda Raf.)

The prediction of leaf area for cherrybark oak (Quercus pagoda Raf.) seedlings is important for studying the physiology of the species. Linear and polynomial models involving leaf length, width, fresh weight, dry weight, and internodal length were tested independently and collectively to predict leaf area. Twenty-nine cherrybark oak seedlings were grown in a greenhouse for one growing season and a total of 468 leaves were collected. Leaf area was polynomially related with leaf length or width, but linearly related with the cross product of length and width. Average leaf area for flush 3 was significantly greater than those of other flushes. However, variation in leaf area among flushes did not affect the models. Relationship between leaf area and length (or width) was consistent. Since leaf length is easy to measure and does not require destruction of leaves, it can be effectively used to predict leaf area in cherrybark oak seedlings

Comparative Gas-Exchange in Leaves of Intact and Clipped, Natural and Planted Cherrybark Oak (Quercus pagoda Raf.) Seedlings

Gas-exchange measurements, including CO2 -exchange rate (net photosynthesis), stomatal conductance, and transpiration, were conducted on intact and clipped cherrybark oak (Quercus pagoda Raf.) seedlings growing in the field and in a nursery bed. Seedlings in the field, released from midstory and understory woody competition, showed significant increases in gas-exchange compared to non-released seedlings due to increases in light levels reaching seedlings. Concurrently, little difference occurred in the CO2 -exchange rate between intact and clipped seedlings in the released treatment although clipped seedlings maintained a consistently greater rate of stomatal conductance. In order to reduce the high variability of light levels recorded in the field, gas-exchange measurements were conducted on intact and clipped cherrybark oak seedlings growing in a nursery bed under consistent light conditions. Again, no differences were found in the CO2 - exchange rate between intact and clipped seedlings. Furthermore, no differences were found in stomatal conductance and transpiration between intact and clipped seedlings. However, significant differences in gas-exchange were found between first-flush and second-flush leaves regardless of seedling treatment (intact or a sprout). Greater rates of gas-exchange in second-flush leaves can be attributed to developing third-flush steams and leaves

Estimulación mecánica de células condrocíticas SW1353 con niveles fisiológicos y patológicos de esfuerzo cortante

ABSTRACT Osteoarthritis is a global musculoskeletal disease, with no disease-modifying drugs, leaving only analgesia and ultimately surgery to reduce pain and disability, affecting up to 80% of people older than 65 years old. There are strong functional interactions among the cartilage, synovium, and subchondral bone, leading to cartilage damage when mechanical loading is excessive chronic or repetitive, by inducing the expression of proinflammatory cytokines, and matrix metalloproteinases. PAR2 has recently been identified as a novel upstream mediator of catabolic events in the osteoarthritic chondrocytes, where its expression is enhanced, but the mechanism by which it promotes osteoarthritis has yet to be clarified. This protein is activated through the cleavage of the N-terminal domain, which can be mimicked by addition of a SLIGKV external peptide and also inhibited by using antibodies that avoid the cleavage. Fluid shear stress onto cell culture has been previously reported as good model of osteoarthritic in vitro studies, inducing the expression of COX2 which through PGE2 produces an increase of proinflammatory cytokines and matrix metalloproteinases, and also the inhibition of PAR2 signal transduction by decreasing PAR2 surface expression by a still unknown mechanism. To gain a deeper understanding of the role of PAR2 as one of the important factors in osteoarthritis, PAR2 protein levels and its location, as well as its gene expression and other important markers were studied in SW1353 chondrocyte-like cells in response to the different types and intensities of fluid shear stress. Results could suggest a direct relation between PAR2 and osteoarthritis, whose protein levels might be dependent on the type and intensity of flow. It was also found that PAR2 was internalized after FSS, suggesting that it could be in response to PGE2. Furthermore, the effect of PAR2 activation and inhibition on the gene expression of other important pathways was also investigated. RESUMEN La osteoartritis (o artrosis) es una enfermedad musculoesquelética, que afecta hasta el 80% de la población mayor de 65 años, para la cual no hay ningún tratamiento curativo basado en fármacos, utilizándose únicamente analgésicos para aliviar el dolor, y la cirugía como última opción. Existen fuertes interacciones entre el cartílago, el liquido sinovial, y el hueso subcondral, que hacen que cuando la carga mecánica es excesiva o crónica, se induzca la expresión de citoquinas proinflamatorias y metaloproteasas de la matriz, que producen daño en el cartílago. PAR2, gen cuya expresión aumenta en la osteoartritis, ha sido identificado recientemente como un nuevo mediador de los eventos catalíticos de la enfermedad, cuyo mecanismo de acción se desconoce. La proteína que codifica, es activada a través del corte de su dominio N-terminal, lo que puede ser imitado por la adición de un péptido externo SLIGKV, o puede ser inhibido usando anticuerpos que impidan la rotura. El uso de un esfuerzo cortante generado por fluido, sobre un cultivo celular, ha demostrado ser un buen modelo para el estudio in vitro de la osteoartritis, induciendo la expresión de COX2, que a través de PGE2 produce un incremento de citoquinas proinflamatorias y metaloproteinasas de la matriz, así como la inhibición de la señal de transducción de PAR2, reduciendo su expresión en la membrana por un mecanismo que se desconoce. Con el objetivo de conocer mejor el papel que juega PAR2, como uno de los factores importantes, en la osteoartritis, sus niveles de expresión proteica y localización, así como su expresión génica y la de otros marcadores importantes, fueron estudiados en células condrocíticas SW1353 en respuesta a diferentes tipos e intensidades de esfuerzos de corte generados por fluido. Los resultados sugieren que puede tratarse de una relación directa entre PAR2 y osteoartritis, siendo la cantidad de proteína PAR2 dependiente del tipo e intensidad del flujo. También se observó que PAR2 aparecía internalizado después del esfuerzo de corte, sugiriendo que podría ser en respuesta a PGE2. Además, también se investigó el efecto de la activación y la inhibición de PAR2 sobre la expresión génica en otras rutas importantes para la osteoartritis

Fall Risk Prediction Using Wearable Wireless Sensors

Wearable wireless sensors and nonlinear dynamics identify postural characteristics relevant to balance control and dynamic stability, revealing predictive risk of falls among older adults

Effects of Hemodialysis Therapy on Sit-to-Walk Characteristics in End Stage Renal Disease Patients

Patients with end stage renal diseases (ESRD) undergoing hemodialysis (HD) have high morbidity and mortality due to multiple causes; one of which is dramatically higher fall rates than the general population. In spite of the multiple efforts aiming to decrease the high mortality and improve quality of life in ESRD patients, limited success has been achieved. If adequate interventions for fall prevention are to be achieved, the functional and mobility mechanisms consistent with falls in this population must be understood. Human movements such as sit-to-walk (STW) tasks are clinically significant, and analysis of these movements provides a meaningful evaluation of postural and locomotor performance in elderly patients with functional limitations indicative of fall risks. In order to assess the effects of HD therapy on fall risks, 22 sessions of both pre- and post-HD measurements were obtained in six ESRD patients utilizing customized inertial measurement units (IMU). IMU signals were denoised using ensemble empirical mode decomposition and Savistky-Golay filtering methods to detect relevant events for identification of STW phases. The results indicated that patients were slower to get out of the chair (as measured by trunk flexion angular accelerations, time to peak trunk flexion, and overall STW completion time) following the dialysis therapy session. STW is a frequent movement in activities of daily living, and HD therapy may influence the postural and locomotor control of these movements. The analysis of STW movement may assist in not only assessing a patient’s physical status, but in identifying HD-related fall risk as well. This preliminary study presents a non-invasive method of kinematic measurement for early detection of increased fall risk in ESRD patients using portable inertial sensors for out-patient monitoring. This can be helpful in understanding the pathogenesis better, and improve awareness in health care providers in targeting interventions to identify individuals at risk for fall

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