Numerical assessment on the effective mechanical stimuli for matrix-associated metabolism in chondrocyte-seeded constructs

The self-regeneration capacity of articular cartilage is limited, due to its avascular and aneural nature. Loaded explants and cell cultures demonstrated that chondrocyte metabolism can be regulated via physiologic loading. However, the explicit ranges of mechanical stimuli that correspond to favourable metabolic response associated with extracellular matrix (ECM) synthesis are elusive. Unsystematic protocols lacking this knowledge produce inconsistent results. This study aims to determine the intrinsic ranges of physical stimuli that increase ECM synthesis and simultaneously inhibit nitric oxide (NO) production in chondrocyte-agarose constructs, by numerically re-evaluating the experiments performed by Tsuang et al. (2008). Twelve loading patterns were simulated with poro-elastic finite element models in ABAQUS. Pressure on solid matrix, von Mises stress, maximum principle stress and pore pressure were selected as intrinsic mechanical stimuli. Their development rates and magnitudes at the steady state of cyclic loading were calculated with MATLAB at the construct level. Concurrent increase in glycosaminoglycan and collagen was observed at 2300 Pa pressure and 40 Pa/s pressure rate. Between 0-1500 Pa and 0-40 Pa/s, NO production was consistently positive with respect to controls, whereas ECM synthesis was negative in the same range. A linear correlation was found between pressure rate and NO production (R = 0.77). Stress states identified in this study are generic and could be used to develop predictive algorithms for matrix production in agarose-chondrocyte constructs of arbitrary shape, size and agarose concentration. They could also be helpful to increase the efficacy of loading protocols for avascular tissue engineering. Copyright (c) 2010 John Wiley \& Sons, Ltd.

The correlation of urethral resistance pressure with maximum urethral closure pressure and stress incontinence

OBJECTIVE: Aim of the study was to correlate urethral retro resistance pressure with the maximum urethral closure pressure (MUCP) and functional urethral length (FUL) in patients with urinary incontinence and healthy individuals. STUDY DESIGN: Two hundred and twenty patients with the complaint of urinary incontinence had a urodynamic examination including urethral pressure profiles and URP. Additionally, 15 healthy individuals without the complaint of any incontinence had their URP and urethral pressure profiles measured. The correlation of MUCP, FUL and URP were calculated using Graph Pad Instat 4.0 for windows. RESULTS: URP correlates well with the diagnosis of urodynamic stress incontinence. Correlation coefficient between URP and MUCP is 0.9262. Healthy individuals have significantly higher values for URP and MUCP. CONCLUSION: URP is a valuable less invasive test than conventional urethral function tests for the diagnosis of urodynamic incontinence with an excellent correlation of MUCP and URP.

Effects of drilling and stress release on hydraulic properties and porewater chemistry of crystalline rocks

The experimental verification of matrix diffusion in crystalline rocks largely relies on indirect methods performed in the laboratory. Such methods are prone to perturbations of the rock samples by collection and preparation and therefore the laboratory-derived transport properties and fluid composition might not represent in situ conditions. We investigated the effects induced by the drilling process and natural rock stress release by mass balance considerations and sensitivity analysis of analytical out-diffusion data obtained from originally saturated, large-sized drillcore material from two locations drilled using traced drilling fluid. For in situ stress-released drillcores of quartz-monzodiorite composition from the Aspo HRL, Sweden, tracer mass balance considerations and 1D and 2D diffusion modelling consistently indicated a contamination of <1% of the original pore water. This chemically disturbed zone extends to a maximum of 0.1 mm into the drillcore (61.8 mm x 180.1 mm) corresponding to about 0.66% of the total pore volume (0.77 vol.%). In contrast, the combined effects of stress release and the drilling process, which have influenced granodioritic drillcore material from 560 m below surface at Forsmark. Sweden, resulted in a maximum contamination of the derived porewater Cl(-) concentration of about 8%. The mechanically disturbed zone with modified diffusion properties covers the outermost similar to 6 mm of the drillcore (50 mm x 189 mm), whereas the chemically disturbed zone extends to a maximum of 0.3 mm based on mass balance considerations, and to 0.15 mm to 0.2 mm into the drillcore based on fitting the observed tracer data. This corresponds to a maximum of 2.4% of the total pore volume (0.62 vol.%) being affected by the drilling-fluid contamination. The proportion of rock volume affected initially by drilling fluid or subsequently with experiment water during the laboratory diffusion and re-saturation experiments depends on the size of the drillcore material and will become larger the smaller the sample used for the experiment. The results are further in support of matrix diffusion taking place in the undisturbed matrix of crystalline rocks at least in the cm range.

[Stress tolerance and quality of life--effect of a comprehensive ambulatory rehabilitation program for patients with chronic heart failure]

Chronic heart failure (CHF) impairs quality of life (QoL) much stronger than other chronic diseases. The objective of this evaluation was to assess the effect of a new integrated comprehensive outpatients rehabilitation program on somatic parameters and quality of life in 51 patients with stable CHF. After rehabilitation, left ventricular ejection fraction, NYHA class, and parameters of sub-maximum and maximum exercise capacity improved significantly between 11 and 20%, and 6-minute walking distance by 58% on average (p < 0.0001). Non-disease specific QoL (Short Form-36 questionnaire) improved in only 2 of 8 subscales (physical functioning [effect size 0.38, p < 0.001], and role functioning [effect size 0.17, p < 0.05]), and a mental component score [effect size 0.47, p < 0.0001]. Disease-specific QoL (Minnesota Living with Heart Failure questionnaire) improved in terms of sum score [effect size 0.24, p < 0.0001], and physical component score [effect size 0.35, p < 0.0001]. Improvement in exercise capacity correlated significantly with improvements in parameters of disease-specific QoL.

The effect of acute exercise and psychosocial stress on fine motor skills and testosterone concentration in the saliva of high school students

Little is known about the influence of different stressors on fine motor skills, the concentration of testosterone (T), and their interaction in adolescents. Therefore, 62 high school students aged 14–15 years were randomly assigned to two experimental groups (exercise, psychosocial stress) and a control group. Exercise stress was induced at 65–75% of the maximum heart rate by running for 15 minutes (n = 24). Psychosocial stress was generated by an intelligence test (HAWIK- IV), which was uncontrollable and characterized by social-evaluative-threat to the students (n=21). The control group followed was part of a regular school lesson with the same duration (n = 28). Saliva was collected after a normal school lesson (pre-test) as well as after the intervention/control period (post-test) and was analyzed for testosterone. Fine motor skills were assessed pre- and post-intervention using a manual dexterity test (Flower Trail) from the Movement Assessment Battery for Children-2. A repeated measure ANCOVA including gender as a covariate revealed a significant group by test interaction, indicating an increase in manual dexterity only for the psychosocial stress group. Correlation analysis of all students shows that the change of testosterone from pre- to post-test was directly linked (r = 2.31, p = .01) to the changes in manual dexterity performance. Participants showing high increases in testosterone from pre- to post-test made fewer mistakes in the fine motor skills task. Findings suggest that manual dexterity increases when psychosocial stress is induced and that improvement of manual dexterity performance corresponds with the increase of testosterone.

Effect of combined drought and heat stress on heat shock proteins in wheat varieties

Introduction: The re sponse of crop plants ex posed on drought or heat shock is related to de crease in the synthesis of normal proteins, accompanied by increased translation of heat shock proteins (HSPs). Though drought and heat stress have been studied individually, little is known about their combined effect on plants. Methods: The wheat (Triticum aestivum L.) varieties (Katya-tolerant, Sadovo or Mladka-susceptible) were potted in soil. Eight-day-old plants were ex posed to with drawing water for seven days. Heat shock was realized in growth chamber at 40 °C for 6h. A combination of drought and heat shock was per formed by subjecting drought-stressed plants to heat shock treatment. Expression of HSPs in the first leaf of wheat varieties was analyzed by SDS electrophoresis and immunoblotting. Polyclonal antibodies against HSP20, HSP60, HSP110 and mononclonal antibodies against HSP70 were used to distinguish the mentioned HSPs. Results: The leaf relative water content (RWC), which indicated the level of plant dehydration decreased significantly (34 %) under drought stressed conditions The electrolyte leakage of ions (EL), representing the level of the cell membrane stability in creased mark edly (68 %), especially under combination of drought and heat. Maximum EL was ob served in drought susceptible varieties Sadovo and Mladka. Drought and heat shock combination in the wheat plants resulted in the induction of specific HSPs. Conclusions: Our results demonstrate that the response of the wheat plants to a combination of drought and heat stress is different from the response of plants to each of these stresses applied separately. Induction of synergetic effect on HSP expression in case of combination between drought and heat was discussed in the case of two contrasting wheat varieties.

The role of cold stress in predicting extra cardiovascular and respiratory admissions

Although several studies have examined effects of air temperature and/or other meteorological variables separately on disease rates, the relationship of meteorological variables and human disease is, in fact, rather complex in the “real-world” [1,2] including the number of potential variables to be considered and their weighting. In other words, 1 °C of air temperature difference in a warm climate may not necessarily mean the same in a cold climate across regions on Earth [3,4]. Why some seasonality was observed in certain regions at certain times only is likely due in part to the imprecise weather estimation from mean, maximum, or minimum air temperature or the definition of study catchments or time period to be included.

Interpretation of fluid inclusions in quartz deformed by weak ductile shearing: reconstruction of differential stress magnitudes and pre-deformation fluid properties

A well developed theoretical framework is available in which paleofluid properties, such as chemical composition and density, can be reconstructed from fluid inclusions in minerals that have undergone no ductile deformation. The present study extends this framework to encompass fluid inclusions hosted by quartz that has undergone weak ductile deformation following fluid entrapment. Recent experiments have shown that such deformation causes inclusions to become dismembered into clusters of irregularly shaped relict inclusions surrounded by planar arrays of tiny, new-formed (neonate) inclusions. Comparison of the experimental samples with a naturally sheared quartz vein from Grimsel Pass, Aar Massif, Central Alps, Switzerland, reveals striking similarities. This strong concordance justifies applying the experimentally derived rules of fluid inclusion behaviour to nature. Thus, planar arrays of dismembered inclusions defining cleavage planes in quartz may be taken as diagnostic of small amounts of intracrystalline strain. Deformed inclusions preserve their pre-deformation concentration ratios of gases to electrolytes, but their H2O contents typically have changed. Morphologically intact inclusions, in contrast, preserve the pre-deformation composition and density of their originally trapped fluid. The orientation of the maximum principal compressive stress (σ1σ1) at the time of shear deformation can be derived from the pole to the cleavage plane within which the dismembered inclusions are aligned. Finally, the density of neonate inclusions is commensurate with the pressure value of σ1σ1 at the temperature and time of deformation. This last rule offers a means to estimate magnitudes of shear stresses from fluid inclusion studies. Application of this new paleopiezometer approach to the Grimsel vein yields a differential stress (σ1–σ3σ1–σ3) of ∼300 MPa∼300 MPa at View the MathML source390±30°C during late Miocene NNW–SSE orogenic shortening and regional uplift of the Aar Massif. This differential stress resulted in strain-hardening of the quartz at very low total strain (<5%<5%) while nearby shear zones were accommodating significant displacements. Further implementation of these experimentally derived rules should provide new insight into processes of fluid–rock interaction in the ductile regime within the Earth's crust.

Growth at moderately elevated temperature alters the physiological response of the photosynthetic apparatus to heat stress in pea (Pisum sativum L.) leaves

The impact of heat stress on the functioning of the photosynthetic apparatus was examined in pea (Pisum sativum L.) plants grown at control (25 °C; 25 °C-plants) or moderately elevated temperature (35 °C; 35 °C-plants). In both types of plants net photosynthesis (Pn) decreased with increasing leaf temperature (LT) and was more than 80% reduced at 45 °C as compared to 25 °C. In the 25 °C-plants, LTs higher than 40 °C could result in a complete suppression of Pn. Short-term acclimation to heat stress did not alter the temperature response of Pn. Chlorophyll a fluorescence measurements revealed that photosynthetic electron transport (PET) started to decrease when LT increased above 35 °C and that growth at 35 °C improved the thermal stability of the thylakoid membranes. In the 25 °C-plants, but not in the 35 °C-plants, the maximum quantum yield of the photosystem II primary photochemistry, as judged by measuring the Fv/Fm ratio, decreased significantly at LTs higher than 38 °C. A post-illumination heat-induced reduction of the plastoquinone pool was observed in the 25 °C-plants, but not in the 35 °C-plants. Inhibition of Pn by heat stress correlated with a reduction of the activation state of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco). Western-blot analysis of Rubisco activase showed that heat stress resulted in a redistribution of activase polypeptides from the soluble to the insoluble fraction of extracts. Heat-dependent inhibition of Pn and PET could be reduced by increasing the intercellular CO2 concentration, but much more effectively so in the 35 °C-plants than in the 25 °C-plants. The 35 °C-plants recovered more efficiently from heat-dependent inhibition of Pn than the 25 °C-plants. The results show that growth at moderately high temperature hardly diminished inhibition of Pn by heat stress that originated from a reversible heat-dependent reduction of the Rubisco activation state. However, by improving the thermal stability of the thylakoid membranes it allowed the photosynthetic apparatus to preserve its functional potential at high LTs, thus minimizing the after-effects of heat stress.

Electrical resistivity change in amorphous Ta42Si13N45 films by stress relaxation

In a first experiment, a reactively sputtered amorphous Ta₄₂Si₁₃N₄₅ film about 260 nm thick deposited on a flat and smooth alumina substrate was thermally annealed in air for 30 min and let cooled again repeatedly at successively higher temperatures from 200 to 500 °C. This treatment successively and irreversibly increases the room temperature resistivity of the film monotonically from its initial value of 670 μΩ cm to a maximum of 705 μΩ cm (+5.2 %). Subsequent heat treatments at temperatures below 500 °C and up to 6 h have no further effect on the room temperature resistivity. The new value remains unchanged after 3.8 years of storage at room temperature. In a second experiment, the evolution of the initially compressive stress of a film similarly deposited by reactive sputtering on a 2-inch silicon wafer was measured by tracking the wafer curvature during similar thermal annealing cycles. A similar pattern of irreversible and reversible changes of stress was observed as for the film resistivity. Transmission electron micrographs and secondary ion mass profiles of the film taken before and after thermal annealing in air establish that both the structure and the composition of the film scarcely change during the annealing cycles. We reason that the film stress is implicated in the resistivity change. In particular, to interpret the observations, a model is proposed where the interface between the film and the substrate is mechanically unyielding.

Standardized pelvic floor exercises improve stress urinary incontinence in women with intrinsic sphincter deficiency.

OBJECTIVES Pelvic floor rehabilitation is the conservative therapy of choice for women with stress urinary incontinence (SUI). The success rate of surgical procedures in SUI patients with intrinsic sphincter deficiency (ISD) is low. The aim of this study was to analyse the effect of a standardized physiotherapy on patients with SUI and normotonic urethra and ISD. METHODS In this study, 64 patients with ISD and 69 patients with normotonic urethra were enrolled. Maximum urethral pressure (MUCP) >20 cm H2 O was considered as normotonic urethral pressure. Before and after physiotherapy MUCP was measured and cough testing was performed. Additionally, patient reported outcome was assessed using the King's Health Questionnaire (KHQ). For statistical analyses Excel 2010 (Microsoft Inc; Redmond, Washington) and SPSS 20 (SPSS Inc; Chicago, Illinois) for Windows were used. Power calculation was based on the primary endpoint incontinence impact and general health. For power calculation, GraphPad Statmate version 2.00 for Windows was used. RESULTS Sixty-four patients with ISD and 69 patients with normotonic urethra were included in the study. In SUI patients with normotonic and hypotonic urethra KHQ-scores regarding the primary endpoins "general health" and "incontinence impact" significantly improved following standardized physiotherapy. In both groups MUCP increased after physiotherapy. In SUI patients with ISD standardized physiotherapy resulted in a decreased incidence of a positive cough test. CONCLUSIONS Standardized physiotherapy should be offered to patients with SUI and ISD. Long-term results are subject to future studies. Neurourol. Urodynam. © 2015 Wiley Periodicals, Inc.

Can urethrolysis resolve outlet obstruction related symptoms after Burch colposuspension for stress urinary incontinence?

OBJECTIVE Bladder outlet obstruction may occur after any incontinence surgery and may present as OAB, hesitancy and or the feeling of incomplete emptying. Aim of this study was to analyze the clinical and urodynamical outcome after urethrolysis in patients presenting with various clinical symptoms after Burch colposuspension for stress urinary incontinence. STUDY DESIGN Between January 2005 and December 2014, all patients who presented with symptoms and with bladder outlet obstruction were included. All patients had undergone Burch or Cowan colposuspension for stress urinary incontinence previously. Primary endpoint was the visual analogue scale (VAS) as measurement of patient perceived disease impact. Secondary endpoints were the various domains of the King's Health Questionnaire, urodynamic parameters as detrusor pressure at maximum flow, residual urine and sonographic bladder wall thickness before and six months after intervention. RESULTS Seventy-two female patients were included in this study whereof 42 suffered from urgency and urge incontinence, 20 from hesitancy and/or slow stream, seven from residual urine of more than 100ml and three from a combination of urgency and residual urine. VAS improved significantly (p<0.0001). Quality of life as determined by the King's Health Questionnaire improved for the domains general health, role limitations, emotions, physical limitations, personal limitations and incontinence impact significantly. Micturition pressure dropped significantly from 43cmH2O (95% CI 19-59cmH2O) to 18cmH2O (95% CI 16-23.5 H2O). Residual urine changed from 110ml (range 20-380ml) to 32ml (20-115ml). Bladder wall thickness decreased from 7mm (95% CI 6.235-7.152) to 5mm (95% CI 5.037-5.607; p<0.01). CONCLUSION Urethrolysis may resolve patients' symptoms and lower micturition pressure but irritative symptoms may persist.