Biological impact of an enhanced recovery after surgery programme in liver surgery.

The clinical and economic impacts of enhanced recovery after surgery (ERAS) programmes have been demonstrated extensively. Whether ERAS protocols also have a biological effect remains unclear. This study aimed to investigate the biological impact of an ERAS programme in patients undergoing liver surgery. A retrospective analysis of patients undergoing liver surgery (2010-2018) was undertaken. Patients operated before and after ERAS implementation in 2013 were compared. Surrogate markers of surgical stress were monitored: white blood cell count (WBC), C-reactive protein (CRP) level, albumin concentration, and haematocrit. Their perioperative fluctuations were defined as Δvalues, calculated on postoperative day (POD) 0 for Δalbumin and Δhaematocrit and POD 2 for ΔWBC and ΔCRP. A total of 541 patients were included, with 223 and 318 patients in non-ERAS and ERAS groups respectively. Groups were comparable, except for higher rates of laparoscopy (24.8 versus 11.2 per cent; P < 0.001) and major resection (47.5 versus 38.1 per cent; P = 0.035) in the ERAS group. Patients in the ERAS group showed attenuated ΔWBC (2.00 versus 2.75 g/l; P = 0.013), ΔCRP (60 versus 101 mg/l; P <0.001) and Δalbumin (12 versus 16 g/l; P < 0.001) compared with those in the no-ERAS group. Subgroup analysis of open resection showed similar results. Multivariable analysis identified ERAS as the only independent factor associated with high ΔWBC (odds ratio (OR) 0.65, 95 per cent c.i. 0.43 to 0.98; P = 0.038), ΔCRP (OR 0.41, 0.23 to 0.73; P = 0.003) and Δalbumin (OR 0.40, 95 per cent c.i. 0.22 to 0.72; P = 0.002). Compared with conventional management, implementation of ERAS was associated with an attenuated stress response in patients undergoing liver surgery

Mitochondrial oxidative stress and nitrate tolerance – comparison of nitroglycerin and pentaerithrityl tetranitrate in Mn-SOD(+/- )mice

BACKGROUND: Chronic therapy with nitroglycerin (GTN) results in a rapid development of nitrate tolerance which is associated with an increased production of reactive oxygen species (ROS). According to recent studies, mitochondrial ROS formation and oxidative inactivation of the organic nitrate bioactivating enzyme mitochondrial aldehyde dehydrogenase (ALDH-2) play an important role for the development of nitrate and cross-tolerance. METHODS: Tolerance was induced by infusion of wild type (WT) and heterozygous manganese superoxide dismutase mice (Mn-SOD(+/-)) with ethanolic solution of GTN (12.5 μg/min/kg for 4 d). For comparison, the tolerance-free pentaerithrityl tetranitrate (PETN, 17.5 μg/min/kg for 4 d) was infused in DMSO. Vascular reactivity was measured by isometric tension studies of isolated aortic rings. ROS formation and aldehyde dehydrogenase (ALDH-2) activity was measured in isolated heart mitochondria. RESULTS: Chronic GTN infusion lead to impaired vascular responses to GTN and acetylcholine (ACh), increased the ROS formation in mitochondria and decreased ALDH-2 activity in Mn-SOD(+/- )mice. In contrast, PETN infusion did not increase mitochondrial ROS formation, did not decrease ALDH-2 activity and accordingly did not lead to tolerance and cross-tolerance in Mn-SOD(+/- )mice. PETN but not GTN increased heme oxygenase-1 mRNA in EA.hy 926 cells and bilirubin efficiently scavenged GTN-derived ROS. CONCLUSION: Chronic GTN infusion stimulates mitochondrial ROS production which is an important mechanism leading to tolerance and cross-tolerance. The tetranitrate PETN is devoid of mitochondrial oxidative stress induction and according to the present animal study as well as numerous previous clinical studies can be used without limitations due to tolerance and cross-tolerance

Agricultural structure and farmers’ interconnections with rural communities

Purpose: In the context of rural development, the question how farmers are interconnected with local rural communities is crucial, as farmers historically have played a key role in rural areas, always shaped by the cultural-systemic context in which they acted. The purpose of this paper is to explore this connection in North-East (NE) Germany and Switzerland, two countries whose agricultural systems can be seen as diametrically opposed to each other with respect to their structure. Design/methodology/approach: The authors conducted a survey on NE German and Swiss farmers to assess the connectivity between farms and rural communities in terms of the farm managers’ perceptions of their social networks, social support, sense of belonging, and active involvement in organizations. Findings: The results show commonalities and differences between both study regions. Smaller farms are characterized by strongly locally based networks and a higher sense of community belonging, whereas larger farms rather have networks with strong ties outside the local dimension. Moreover, farmers’ local origin and farm diversification are positively associated with strengthening the connection between farms and local communities. Off-farm work is a means for this connection only in NE Germany. Originality/value: This paper contributes to the discussion about adverse effects of farming scale and corporate farming on community well-being by simultaneously delivering insights into two structurally different agricultural systems. At the same time the approach allows for a comparison between the systems

Residue-resolved stability of full-consensus ankyrin repeat proteins probed by NMR

We investigated the stability determinants and the unfolding characteristics of full-consensus Designed Ankyrin Repeat Proteins (DARPins) by NMR. Despite the repeating sequence motifs, the resonances could be fully assigned using 1H, 15N, 13C triple labeled proteins. To remove further ambiguities, paramagnetic spin labels were attached to either end of these elongated proteins which attenuate the resonances of the spatially closest residues. Deuterium exchange experiments of DARPins with 2 and 3 internal repeats between N- and C-terminal capping repeats (NI2C, NI3C) and NI3C_Mut5, where the C-cap had been reengineered, indicate that the stability of the full-consensus ankyrin repeat proteins is strongly dependent on the coupling between repeats, as the stabilized cap decreases the exchange rate throughout the whole protein. Some amide protons require more than a year to exchange at 37°C, highlighting the extraordinary stability of the proteins. Denaturant induced unfolding, followed by deuterium exchange, chemical shift change and heteronuclear nuclear Overhauser effects, is consistent with an Ising-type description of equilibrium folding for NI3C_Mut5, while for native state deuterium exchange, we postulate local fluctuations to dominate exchange as unfolding events are too slow in these very stable proteins. The location of extraordinarily slowly exchanging protons indicate a very stable core structure in the DARPins which combines hydrophobic shielding with favorable electrostatic interactions. These investigations help the understanding of repeat protein architecture and the further design of DARPins for biomedical applications where high stability is required

Soft biomimetic nanoconfinement promotes amorphous water over ice

Water is a ubiquitous liquid with unique physicochemical properties, whose nature has shaped our planet and life as we know it. Water in restricted geometries has different properties than in bulk. Confinement can prevent low-temperature crystallization of the molecules into a hexagonal structure and thus create a state of amorphous water. To understand the survival of life at subzero temperatures, it is essential to elucidate this behaviour in the presence of nanoconfining lipidic membranes. Here we introduce a family of synthetic lipids with designed cyclopropyl modifications in the hydrophobic chains that exhibit unique liquid-crystalline behaviour at low temperature, which enables the maintenance of amorphous water down to ~10 K due to nano-confinement. The combination of experiments and molecular dynamics simulations unveils a complex lipid–water phase diagram in which bicontinuous cubic and lamellar liquid crystalline phases that contain subzero liquid, glassy or ice water emerge as a competition between the two components, each pushing towards its thermodynamically favoured state

NMR investigation of structures of G-protein coupled receptor folding intermediates

Folding of G-protein coupled receptors (GPCRs) according to the two-stage model (Popot, J. L., and Engelman, D. M. (1990) Biochemistry 29, 4031–4037) is postulated to proceed in 2 steps: partitioning of the polypeptide into the membrane followed by diffusion until native contacts are formed. Herein we investigate conformational preferences of fragments of the yeast Ste2p receptor using NMR. Constructs comprising the first, the first two, and the first three transmembrane (TM) segments, as well as a construct comprising TM1–TM2 covalently linked to TM7 were examined. We observed that the isolated TM1 does not form a stable helix nor does it integrate well into the micelle. TM1 is significantly stabilized upon interaction with TM2, forming a helical hairpin reported previously (Neumoin, A., Cohen, L. S., Arshava, B., Tantry, S., Becker, J. M., Zerbe, O., and Naider, F. (2009) Biophys. J. 96, 3187–3196), and in this case the protein integrates into the hydrophobic interior of the micelle. TM123 displays a strong tendency to oligomerize, but hydrogen exchange data reveal that the center of TM3 is solvent exposed. In all GPCRs so-far structurally characterized TM7 forms many contacts with TM1 and TM2. In our study TM127 integrates well into the hydrophobic environment, but TM7 does not stably pack against the remaining helices. Topology mapping in microsomal membranes also indicates that TM1 does not integrate in a membrane-spanning fashion, but that TM12, TM123, and TM127 adopt predominantly native-like topologies. The data from our study would be consistent with the retention of individual helices of incompletely synthesized GPCRs in the vicinity of the translocon until the complete receptor is released into the membrane interior