Explore the vast range of titles available.

Cytochrome c oxidase (COX), the rate-limiting enzyme of mitochondrial respiration, is regulated by various mechanisms. Its regulation by ATP (adenosine triphosphate) appears of particular importance, since it evolved early during evolution and is still found in cyanobacteria, but not in other bacteria. Therefore the “allosteric ATP inhibition of COX” is described here in more detail. Most regulatory properties of COX are related to “supernumerary” subunits, which are largely absent in bacterial COX. The “allosteric ATP inhibition of COX” was also recently described in intact isolated rat heart mitochondria.

Background Evidence on antibiotic-loaded bone cement remains too vague to guide kyphoplasty in patient care. We clinically evaluated the properties and benefits of a new low viscosity polymethylmethacrylate (PMMA) bone cement loaded with gentamicin. Methods In this non-randomised, monocentric, prospective open trial, 50 consecutively enrolled patients with fractures of the vertebral body (TH7-L4) due to osteoporosis or trauma were investigated between 2010 and 2013, with a 1-year post-op follow-up per patient. The antibiotic-loaded PMMA bone cement was administered to patients during the surgery according to the standard procedure established on site for one-staged kyphoplasty. The clinical outcome was assessed according to function and pain by standardised anamnesis, clinical investigation, validated visual analogue scale (VAS) vertebral spine score, Oswestry Low-Back-Pain (ODI) Disability score, and Short Form (SF)-36 score. We further performed X-ray and magnetic resonance imaging with radiomorphometric assessment. Results The patients showed beneficial effects concerning low back pain disability (mean ODI score; screening, 68.0 ± 15.8% vs month 12, 42.8 ± 24.5%). The pain level was decreased (VAS vertebral spine score; screening, 68.8 ± 17.6 vs month 12, 43.8 ± 22.2) and the general health state was improved (SF-36; especially ‘role limitations due to emotional problems’ (51.9 ± 44.7; month 6), followed by ‘role limitations due to physical health’ (36.1 ± 42.4; month 6), and ‘pain’ (34.6 ± 35.3; month 6)). No vertebral infection did occur during the hospital stay or the 1-year follow-up. The stabilisation and restoration of the fractured bodies were radiologically confirmed. A reduced rate of leakage was observed, combined with a decreased risk of infection and an improved patient safety after a 1-year follow-up period. Conclusion Requirements for bone cement in a kyphoplasty setting were excellently fulfilled. Application technique and cement properties may influence the success of the surgery. Trial registration Deutsche Institut für Medizinische Dokumentation und Information (DIMDI), HM-KS-0901, Registered 14 September 2009, https://www.dimdi.de/dynamic/de/medizinprodukte/datenbankrecherche/

This study addresses the eventual consequence of cytochrome c oxidase (CytOx) inhibition by ATP at high ATP/ADP ratio in isolated rat heart mitochondria. Earlier, it has been demonstrated that the mechanism of allosteric ATP inhibition of CytOx is one of the key regulations of mitochondrial functions. It is relevant that aiming to maintain a high ATP/ADP ratio for the measurement of CytOx activity effectuating the enzymatic inhibition as well as mitochondrial respiration, optimal concentration of mitochondria is critically important. Likewise, only at this concentration, were the differences in ΔΨm and ROS concentrations measured under various conditions significant. Moreover, when CytOx activity was inhibited in the presence of ATP, mitochondrial respiration and ΔΨm both remained static, while the ROS production was markedly decreased. Consubstantial results were found when the electron transport chain was inhibited by antimycin A, letting only CytOx remain functional to support the energy production. This seems to corroborate that the decrease in mitochondrial ROS production is solely the effect of ATP binding to CytOx which results in static respiration as well as membrane potential.

A key requirement for three-dimensional printing (3-DP) of medical implants is the availability of printable and biocompatible powder-binder systems. In this study we developed a powder mixture comprising tetracalcium phosphate (TTCP) as reactive component and beta-tricalcium phosphate (beta-TCP) or calcium sulfate as biodegradable fillers, which can be printed with an aqueous citric acid solution. The potential of this material combination was demonstrated printing various devices with intersecting channels and filigree structures. Two post-processing procedures, a sintering and a polymer infiltration process were established to substantially improve the mechanical properties of the printed devices. Preliminary examinations on relevant application properties including in vitro cytocompatibility testing indicate that the new powder-binder system represents an efficient approach to patient specific ceramic bone substitutes and scaffolds for bone tissue engineering.

Sugar beet ( Beta vulgaris ssp. vulgaris) is a biennial, sucrose-storing plant, which is mainly cultivated as a spring crop and harvested in the vegetative stage before winter. For increasing beet yield, over-winter cultivation would be advantageous. However, bolting is induced after winter and drastically reduces yield. Thus, post-winter bolting control is essential for winter beet cultivation. To identify genetic factors controlling bolting after winter, a F2 population was previously developed by crossing the sugar beet accessions BETA 1773 with reduced bolting tendency and 93161P with complete bolting after winter. For a mapping-by-sequencing analysis, pools of 26 bolting-resistant and 297 bolting F2 plants were used. Thereby, a single continuous homozygous region of 103 kb was co-localized to the previously published BR 1 QTL for post-winter bolting resistance (Pfeiffer et al.,2014 ). The BR 1 locus was narrowed down to 11 candidate genes from which a homolog of the Arabidopsis CLEAVAGE AND POLYADENYLATION SPECIFICITY FACTOR 73-I ( CPSF73-I ) was identified as the most promising candidate. A 2 bp deletion within the BETA 1773 allele of BvCPSF73-Ia results in a truncated protein. However, the null allele of BvCPSF73-Ia might partially be compensated by a second BvCPSF73-Ib gene. This gene is located 954 bp upstream of BvCPSF73-Ia and could be responsible for the incomplete penetrance of the post-winter bolting resistance allele of BETA 1773. This result is an important milestone for breeding winter beets with complete bolting resistance after winter.

Background: The number of periprosthetic joint infections caused by vancomycin-resistant pathogens is increasing. Currently, no PMMA cement is commercially available to cover VRE. Daptomycin shows promising results in treating infection, offering a good safety profile and a reduced risk of developing resistance. The purpose of this in vitro study was to investigate the mechanical stability, handling properties, elution behavior, and antimicrobial effectiveness of PMMA cement loaded with three different daptomycin concentrations in comparison to commercially available antibiotic-loaded bone cement (ALBC). Methods: Mechanical properties and handling characteristics (ISO 5833, DIN 53435), HPLC elution, antimicrobial effectiveness with proliferation assay (DIN 17025), and inhibition zone testing were investigated. Results: All tested daptomycin concentrations met the ISO and DIN standards for mechanical strength. Loading of 40 g of PMMA cement with 0.5 g of daptomycin did not show any antimicrobial effectiveness, in contrast to 1.0 g and 1.5 g. PMMA cement with 1.5 g of daptomycin was the best in terms of elution and effectiveness, and it showed good ISO mechanical strength; ISO doughing was sticky for a little longer and setting was faster compared to the vancomycin-containing reference cement. Conclusion: PMMA cement containing 0.5 g of gentamicin and 1.5 g of daptomycin could be a good alternative to the already established COPAL® (Wehrheim, Germany) G+V for the treatment of PJIs caused by VRE.

Background: The mitral valve apparatus is a complex system that requires sufficient function of all involved structures. Previous studies have demonstrated that ventricular remodeling can cause displacement of subannular structures, including the papillary muscles, which in turn promotes the development of mitral regurgitation. Furthermore, in such cases, annuloplasty alone is often insufficient to restore optimal valve function. Instead, additional reconstruction of the subannular apparatus is associated with improved clinical outcomes. Our study aimed to analyze the topography of the papillary muscles in the mitral valve complex and their relevance for mitral valve function. Methods: In 148 patients who underwent both cardiac computed tomography (CT) and echocardiography, the position of the papillary muscles within the left ventricle was assessed. CT scans were evaluated in end-diastolic four-chamber view, two-chamber view, and short-axis view. CT analysis involved determining the position of the papillary muscles based on a modified left ventricular segmentation scheme, which subdivided the original segments into “a” and “b” subsegments in a counterclockwise manner. Furthermore, the midventricular diameter, ventricular length, as well as the angle between the papillary muscle (PM) and the left ventricular wall, were measured. Comorbidities were assessed. The presence of mitral regurgitation (MR) and ejection fraction was determined based on echocardiographic data. Echocardiography was conducted either as part of initial cardiological assessments or during follow-up examinations. For detailed statistical analysis, the patients were divided into the following groups: control group, MR-only group, coronary heart disease (CHD)-only group, and combined CHD and MR subgroup. Results: Mitral regurgitation was significantly correlated with age (p < 0.001) and hypertension (r = 0.1900, p = 0.0208), and in the MR-only subgroup, additionally with atrial fibrillation (r = 0.2426, p = 0.0462). The length (p < 0.001) and internal diameter (p < 0.001) of the left ventricle were significantly larger in men than in women. Different positions of the papillary muscles were identified. Segment 7a was significantly correlated with MR in the combined CHD and MR subgroup. In normal-sized ventricles, patients with MR and papillary muscle in 12a (p = 0.0095) or 10a (p = 0.0460) showed a significantly larger angle than patients without MR (overall dataset). Conclusions: Assessment of papillary muscle position is essential in diagnosing mitral regurgitation and should guide the consideration of subannular repair during surgical treatment.

Cytochrome c oxidase (CytOx), the oxygen-accepting and rate-limiting enzyme of mitochondrial respiration, binds with 10 molecules of ADP, 7 of which are exchanged by ATP at high ATP/ADP-ratios. These bound ATP and ADP can be exchanged by cholate, which is generally used for the purification of CytOx. Many crystal structures of isolated CytOx were performed with the enzyme isolated from mitochondria using sodium cholate as a detergent. Cholate, however, dimerizes the enzyme isolated in non-ionic detergents and induces a structural change as evident from a spectral change. Consequently, it turns off the “allosteric ATP-inhibition of CytOx”, which is reversibly switched on under relaxed conditions via cAMP-dependent phosphorylation and keeps the membrane potential and ROS formation in mitochondria at low levels. This cholate effect gives an insight into the structural-functional relationship of the enzyme with respect to ATP inhibition and its role in mitochondrial respiration and energy production.

The pathogenesis of aortic aneurysm and dissection continues to be under discussion. Extracellular matrix (ECM) remodeling processes in the aortic wall are hypothesized to be involved in the development of the disorders. Therefore, in a histological study, we investigated the expression of metalloproteases 1 and 9 (MMP1 and MMP9) and their inhibitors (TIMP 1 and TIMP 2) in cardiac surgery patients. In parallel, we studied the aortic roots by echocardiography. Clinical reports of 111 patients (30 women and 81 men) who suffered from aortic aneurysms and aortic dissection were evaluated and studied by transesophageal echocardiography. Seven patients who had coronary heart disease served as “healthy controls”. All patients underwent the necessary surgical procedure according to the diagnosed aortic disease in the period from 2007 to 2015. A tissue sample of the aortic biopsies was collected from each patient during surgery. Immunohistochemical staining was performed for MMP1 and MMP9 and TIMP1 and TIMP2 as well. Vascularization was monitored by a CD 31 antibody. In direct comparison, the expressions are not homogeneous. We found the smallest changes in the intima area at all. TIMP 1 and TIMP 2 distribution increases from the lumen of the vessel outward in the wall layers of the aorta. In the case of arteriosclerotic changes, intima had a capillarization, but not in the media. An opposite pattern was found in the dissected aortas. There are differences in the vascularization between the aneurysm and dissection and the different layers, respectively. A different remodeling process of the ECM in comparison to the vascular layers must be hypothesized. Reading the patterns of staining and with regard to the known inhibitory effect of MMP9 on ECM remodeling, but especially TIMP 2 on neoangiogenesis, disturbed nutrition, and dysfunctional vasa vasorum remodeling must be assumed as causes of dissection.

Aims The conditions of hypoxia are suggested to induce permanent atrial fibrillation (AF). The regulation of COX4I2 and COX4I1 depends on oxygen availability in tissues. A role of COX4I2 in the myocardium of AF patients is supposed for pathogenesis of AF and subsequent alterations in the electron transfer chain (ETC) under hypoxia. Methods and results In vitro, influence of hypoxia on HeLa 53 cells was studied and elevated parts of COX 4I2 were confirmed. Myocardial biopsies were taken ex vivo from the patients' Right Atria with SR (n = 31) and AF (n = 11), respectively. RT‐ PCR for mRNA expresson, mitochondrial respiration by polarography and the protein content of cytochrome c oxidase (CytOx) subunit 4I1 and CytOx subunit 4I2 by ELISA were studied. Clinical data were correlated to the findings of gene expressions in parallel. Patients with permanent AF had a change in isoform 4I2/4I1 expression along with a decrease of isoform COX 4I1 expression. The 4I2/4I1 ratio of mRNA expression was increased from 0.630 to 1.058 in comparison. However, the protein content of CytOx subunit 4 was much lower in the AF group, whereas the respiration/units enzyme activity in both groups remained the same. Conclusions This study describes a possible molecular correlate for the development of AF. Due to the known functional significance of COX 4I2, mitochondrial dysfunction can be assumed as a part of the pathogenesis of AF.