The hydrogen peroxide-sensitive proteome of the chloroplast in vitro and in vivo

Muthuramalingam M, Matros A, Scheibe R, Mock H-P, Dietz K-J. The hydrogen peroxide-sensitive proteome of the chloroplast in vitro and in vivo. Frontiers in Plant Science. 2013;4:54-1-54-14.Hydrogen peroxide (H2O2) evolves during cellular metabolism and accumulates under various stresses causing serious redox imbalances. Many proteomics studies aiming to identify proteins sensitive to H2O2 used concentrations that were above the physiological range. Here the chloroplast proteins were subjected to partial oxidation by exogenous addition of H2O2 equivalent to 10% of available protein thiols which allowed for the identification of the primary targets of oxidation. The chosen redox proteomic approach employed differential labeling of non-oxidized and oxidized thiols using sequential alkylation with N-ethylmaleimide and biotin maleimide. The in vitro identified proteins are involved in carbohydrate metabolism, photosynthesis, redox homeostasis, and nitrogen assimilation. By using methyl viologen that induces oxidative stress in vivo, mostly the same primary targets of oxidation were identified and several oxidation sites were annotated. Ribulose-1,5-bisphosphate (RubisCO) was a primary oxidation target. Due to its high abundance, RubisCO is suggested to act as a chloroplast redox buffer to maintain a suitable redox state, even in the presence of increased reactive oxygen species release. 2-cysteine peroxiredoxins (2-Cys Prx) undergo redox-dependent modifications and play important roles in antioxidant defense and signaling. The identification of 2-Cys Prx was expected based on its high affinity to H2O2 and is considered as a proof of concept for the approach. Targets of Trx, such as phosphoribulokinase, glyceraldehyde-3-phosphate dehydrogenase, transketolase, and sedoheptulose-1,7-bisphosphatase have at least one regulatory disulfide bridge which supports the conclusion that the identified proteins undergo reversible thiol oxidation. In conclusion, the presented approach enabled the identification of early targets of H2O2 oxidation within the cellular proteome under physiological experimental conditions

Comparison between transperineal ultrasound and digital dectection of levator ani trauma : can we improve the odds?

Aims To investigate the predictive ability of four digital assessment parameters to detect levator ani (LA) muscle defects (avulsion injury) and compare these to transperineal tomographic ultrasound images. Methods This was an observational study imbedded in a larger quasi-experimental cohort study for women with urinary incontinence. Seventy-two women, ≥60 years who had attended or were going to attend physiotherapy for treatment of urinary incontinence, were included in the study. Inclusion criteria from the parent study were symptoms of stress, urge or both types of urinary incontinence. The predictive ability of the following digital parameters: direct palpation of a discontinuity of the LA muscle from insertion on the pubic ramus; palpation of the distance between the muscle insertion sites; palpation of LA strength; palpation of LA tone, were analyzed against findings from tomographic transperineal ultrasound images. Correlation between methods was measured using Cohen's kappa for each of the individual parameters. Results Seventeen women (24%) presented with a complete or partial avulsion of the puborectalis muscle as diagnosed with tomographic ultrasound imaging. Nine women (13%) had complete avulsions, one of which was bilateral. The predictive ability of the digital assessment parameters varied from poor (k = 0.187, 95% CI [0.02–0.36]) to moderate (k = 0.569, 95% CI [0.31–0.83]). The new parameter of ‘width between insertion sites’ performed best. Conclusions Adding the parameter of “width between insertion sites” appears to enhance our ability to detect avulsion of the levator ani (LA) muscle by digital examination however it does not distinguish between unilateral or bilateral avulsion

Pelvic organ prolapse symptoms in relation to POPQ, ordinal stages and ultrasound prolapse assessment

Adequate staging of pelvic organ prolapse is important in clinical practice and research. The ability of the POPQ, ordinal stages and ultrasound prolapse assessment were evaluated for their ability to discriminate between women with and without prolapse symptoms. The leading edge of the predominant compartment in the three assessment systems was used for the calculation of receiver operating characteristics curves. Two hundred and sixty five (265) consecutive women were evaluated. The area under the receiver operating characteristics curve for the three staging systems ranged from 0.715 to 0.783. POPQ staging and ordinal staging performed equally well in the prediction of prolapse symptoms (p = 0.780), and both performed better as compared with ultrasound prolapse assessment (p = 0.048 and p = 0.015, respectively). Prolapse staging can equally be performed by the POPQ and ordinal stages systems as far as the discrimination between women with and without prolapse symptoms is concerned. The ultrasound prolapse assessment does not perform better as compared with these two systems

Function and Regulation of Chloroplast Peroxiredoxin IIE

Peroxiredoxins (PRX) are thiol peroxidases that are highly conserved throughout all biological kingdoms. Increasing evidence suggests that their high reactivity toward peroxides has a function not only in antioxidant defense but in particular in redox regulation of the cell. Peroxiredoxin IIE (PRX-IIE) is one of three PRX types found in plastids and has previously been linked to pathogen defense and protection from protein nitration. However, its posttranslational regulation and its function in the chloroplast protein network remained to be explored. Using recombinant protein, it was shown that the peroxidatic Cys121 is subjected to multiple posttranslational modifications, namely disulfide formation, S-nitrosation, S-glutathionylation, and hyperoxidation. Slightly oxidized glutathione fostered S-glutathionylation and inhibited activity in vitro. Immobilized recombinant PRX-IIE allowed trapping and subsequent identification of interaction partners by mass spectrometry. Interaction with the 14-3-3 υ protein was confirmed in vitro and was shown to be stimulated under oxidizing conditions. Interactions did not depend on phosphorylation as revealed by testing phospho-mimicry variants of PRX-IIE. Based on these data it is proposed that 14-3-3υ guides PRX‑IIE to certain target proteins, possibly for redox regulation. These findings together with the other identified potential interaction partners of type II PRXs localized to plastids, mitochondria, and cytosol provide a new perspective on the redox regulatory network of the cell

Automatic segmentation method of pelvic floor levator hiatus in ultrasound using a self-normalising neural network

Segmentation of the levator hiatus in ultrasound allows to extract biometrics which are of importance for pelvic floor disorder assessment. In this work, we present a fully automatic method using a convolutional neural network (CNN) to outline the levator hiatus in a 2D image extracted from a 3D ultrasound volume. In particular, our method uses a recently developed scaled exponential linear unit (SELU) as a nonlinear self-normalising activation function, which for the first time has been applied in medical imaging with CNN. SELU has important advantages such as being parameter-free and mini-batch independent, which may help to overcome memory constraints during training. A dataset with 91 images from 35 patients during Valsalva, contraction and rest, all labelled by three operators, is used for training and evaluation in a leave-one-patient-out cross-validation. Results show a median Dice similarity coefficient of 0.90 with an interquartile range of 0.08, with equivalent performance to the three operators (with a Williams' index of 1.03), and outperforming a U-Net architecture without the need for batch normalisation. We conclude that the proposed fully automatic method achieved equivalent accuracy in segmenting the pelvic floor levator hiatus compared to a previous semi-automatic approach

The clinical application of transperineal ultrasound in urogynaecology

KEY CONTENT : Transperineal ultrasound allows reproducible imaging of pelvic floor conditions that aids in the thorough assessment required to diagnose and treat urogynaecological conditions. Views that can be obtained include two-dimensional (2D) sagittal views of the bladder neck, urethra and pelvic floor; 2D coronal views of the anal canal; and three-dimensional (3D) or four-dimensional (4D) views of the genital hiatus and anal canal. This allows assessment of the post-void residual volumes, detrusor wall thickness and dynamic assessment of the urethral morphology. Ultrasonographic assessment enables accurate information about maternal birth trauma to be ascertained, including levator ani muscle avulsion and obstetric anal sphincter injury. Transperineal ultrasound can be used to identify and assess previously implanted vaginal mesh and midurethral slings. LEARNING OBJECTIVES : To understand the role of ultrasound in clinical urogynaecology practice, including the assessment of slings and meshes. To know the ultrasound probes, techniques and views used to image the pelvic floor and anal sphincters by transperineal ultrasound. To describe assessment of the lower urinary tract, pelvic organ prolapse and obstetric anal sphincter injury using ultrasound. ETHICAL ISSUES : Thorough assessment of the pelvic floor is mandatory against the background of technological advances in the investigation of pelvic floor dysfunction. As a common and major complication of childbirth, maternal birth trauma must be assessed fully to support primary and secondary prevention. Thorough assessment must underlie the use of mesh implants, and dealing with sling and mesh complications is enhanced by imaging.https://obgyn.onlinelibrary.wiley.com/journal/17444667hj2023Obstetrics and GynaecologyUrolog

Blood Transfusion and Spread of Variant Creutzfeldt-Jakob Disease

The effect of reducing vCJD transmission by excluding potential blood donors who have received a blood transfusion can be quantified and depends on the absolute number of cases observed or expected

Quality of Life of Patients with Head and Neck Cancer Receiving Cetuximab, Fluorouracil, Cisplatin Comparing to Cetuximab, Fluorouracil, Cisplatin, and Docetaxel within the CEFCID Trial

Introduction: CeFCiD was a multicenter phase II study comparing the efficacy of cetuximab (C), 5-flourouracil, and cisplatin with the same regimen adding docetaxel (D) in recurrent/metastatic head and neck cancer. The primary analysis trial did not demonstrate survival benefit from therapy intensification in first-line recurrent and/or metastatic squamous cell carcinoma of the head and neck (SCCHN). The current analysis of the trial assessed the impact of treatment on quality of life (QoL). Methods: The European Organization for Research and Treatment of Cancer Quality of life Questionnaire QLQ-C30 and the tumor-specific module for head and neck cancer (QLQ-H&N35) were used to assess QoL at baseline (visit 1), after 2 (visit 3), 4 (visit 5), and 6 (visit 7) cycles of chemotherapy. Results: Of 180 patients included in this study, 86 patients (47.8%) completed the questionnaires at baseline. Considering selected scores over treatment time, there was no difference in global QoL, dyspnea, swallowing, and speech between the treatment arms in the course. For fatigue, a significant increase from baseline to visit 3 (p = 0.02), visit 5 (p = 0.002), and to visit 7 (p = 0.003) was observed for patients receiving D, cisplatin or carboplatin (P), 5-fluorouracil (F), and C. At the end of chemotherapy, the manifestation of fatigue was similar compared in the 2 treatment arms. Discussion/Conclusion: Therapy intensification not adversely affects selected scores of QoL of patients with recurrent and/or metastatic SCCHN. Nevertheless, fatigue seems to be pronounced in patients treated with D