Inflammation initiated by stressed organelles

Key cellular functions including those related to energy metabolism, organization of the genetic information or production of membrane-bound and secreted proteins are compartmentalized within organelles. Various stresses such as differentiation programs, viral and bacterial infections, perturbations in protein production, mechanical constraints, changes in the environment and nutriment accessibility can impact cellular homeostasis and organelle integrity. Perturbations of these cellular compartments trigger repair and adaptation programs aimed at restoring homeostasis. These events are often associated with low-grade inflammation also termed parainflammation. While the nature and mechanisms of danger signals released by irremediably damaged cells are well understood, how transiently stressed cells trigger inflammation is still poorly understood. Emerging studies highlighted new mechanisms by which stress pathways promote inflammation. Cytosolic innate immune pathways are engaged by signals stemming from perturbed organelles such as the mitochondria, the endoplasmic reticulum (ER) or the nuclear envelope (NE). These observations indicate that these pathways function as guardians of cellular homeostasis and may contribute to disease in pathologies characterized by perturbations of cellular homoeostasis. Mitochondria-stress, ER-stress or NE-stress are emerging as proinflammatory signals that contribute to human conditions and diseases.     

Cortical bone trajectory screws for circumferential arthrodesis in lumbar degenerative spine: clinical and radiological outcomes of 101 cases

Purpose

The use of cortical bone trajectory (CBT) pedicle screws for circumferential interbody fusion represents a viable alternative for single-level procedure with reduced invasiveness and less tissue destruction than the traditional technique. In addition, CBT screws have a potentially stronger pullout strength because of the greater amount of cortical bone intercepted. Only few series exist evaluating clinical and radiological outcomes of CBT screws.

Methods

This is a retrospective cohort study. All patients that underwent circumferential lumbar interbody fusion with CBT screws in our institution from 2014 to 2017 were reviewed. Patient demographics, clinical outcome with visual analogue scale (VAS) and Oswestry Disability Index (ODI), radiological data such as fusion, lordosis and muscle trauma, operative blood loss, hospital stay and use of fluoroscopy were evaluated.

Results

A total of 101 patients undergoing CBT-arthrodesis for degenerative lumbo-sacral disease were reviewed. Mean procedural time was 187 min. The mean operative blood loss and X-ray dose per procedure was 383 ml and 1.60 mg cm², respectively. The mean hospital stay was 3.47 days. The mean follow-up was 18.23 months. Mean lordosis increment at the treated level was 4.2°. When the follow-up was longer than 12 months (53% of patients), fusion was obtained in 94% of cases. Mean ODI and VAS index improved with statistical significance.

Conclusions

This is to our knowledge that the largest available study regarding CBT for circumferential arthrodesis. Results underlined the safety of this technique and the promising clinical and radiological outcomes that will need a longer follow-up.

Graphical abstract

These slides can be retrieved under Electronic Supplementary material.

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Vaginal cystocele repair and hysteropexy in women with anterior and central compartment prolapse: efficacy and safety after 30 months of follow-up

Introduction and hypothesis

The aim of this study was to assess the safety and efficacy of vaginal native tissue repair and uterine suspension after a follow-up of at least 1 year.

Methods

We included all consecutive women with an anterior vaginal prolapse of stage II or higher and a concomitant uterine prolapse of stage II who underwent this surgical procedure. We considered women with a descensus with maximum point of less than ?1 in any compartment as objectively cured. Overall success was defined as no prolapse symptoms, together with a Patient Global Impression of Improvement (PGI-I) score of 2 or less, prolapse of stage lower than II, and no need for other surgery.

Results

A total of 102 patients underwent this surgical procedure during the study period and met all the inclusion criteria for statistical analysis. The mean follow-up was 31 ± 8.2 months; no patient was lost to follow-up. Five patients (4.9%) showed postoperative complications. In terms of subjective outcomes, at the last available follow-up, failure of this surgical procedure was seen in 2% of patients. The objective cure rate and the overall cure rate were the 95.1%. No significant deterioration in objective cure rates was observed over time (p = 0.6).

Conclusions

Vaginal repair and hysteropexy appear to be an effective and safe option for women with advanced uterovaginal prolapse.

     

Lymph node pick up by separate stations: Option or necessity

AIM: To evaluate whether lymph node pick up by separate stations could be an indicator of patients submitted to appropriate surgical treatment. METHODS: One thousand two hundred and three consecutive gastric cancer patients submitted to radical resection in 7 general hospitals and for whom no information was available on the extension of lymphatic dissection were included in this retrospective study. RESULTS: Patients were divided into 2 groups: group A, where the stomach specimen was directly formalinfixed and sent to the pathologist, and group B, where lymph nodes were picked up after surgery and fixed for separate stations. Sixty-two point three percent of group A patients showed 16 retrieved lymph nodes compared to 19.4% of group B(P 0.0001). Group B(separate stations) patients had significantly higher survival rates than those in group A [46.1 mo(95%CI: 36.5-56.0) vs 27.7 mo(95%CI: 21.3-31.9); P = 0.0001], independently of T or N stage. In multivariate analysis, group A also showed a higher risk of death than group B(HR = 1.24; 95%CI: 1.05-1.46).CONCLUSION: Separate lymphatic station dissection increases the number of retrieved nodes, leads to better tumor staging, and permits verification of the surgical dissection. The number of dissected stations could potentially be used as an index to evaluate the quality of treatment received.     

Comparative analysis of real-time PCR assays in the detection of canine visceral leishmaniasis

Parasitology Research - Dogs are important hosts and reservoirs of leishmaniasis, a disease caused by protozoan parasites from the genus Leishmania, affecting ~12 million people worldwide. The...     

An inhibitor persistently decreased enteric methane emission from dairy cows with no negative effect on milk production

A quarter of all anthropogenic methane emissions in the United States are from enteric fermentation, primarily from ruminant livestock. This study was undertaken to test the effect of a methane inhibitor, 3-nitrooxypropanol (3NOP), on enteric methane emission in lactating Holstein cows. An experiment was conducted using 48 cows in a randomized block design with a 2-wk covariate period and a 12-wk data collection period. Feed intake, milk production, and fiber digestibility were not affected by the inhibitor. Milk protein and lactose yields were increased by 3NOP. Rumen methane emission was linearly decreased by 3NOP, averaging about 30% lower than the control. Methane emission per unit of feed dry matter intake or per unit of energy-corrected milk were also about 30% less for the 3NOP-treated cows. On average, the body weight gain of 3NOP-treated cows was 80% greater than control cows during the 12-wk experiment. The experiment demonstrated that the methane inhibitor 3NOP, applied at 40 to 80 mg/kg feed dry matter, decreased methane emissions from high-producing dairy cows by 30% and increased body weight gain without negatively affecting feed intake or milk production and composition. The inhibitory effect persisted over 12 wk of treatment, thus offering an effective methane mitigation practice for the livestock industries.The livestock sector is a significant source of greenhouse gas (GHG) emissions in the United States and globally (1, 2). In the United States, enteric fermentation of feed by ruminants is the largest source of anthropogenic methane emissions (0.14 Gt of CO₂ Eq. in 2012; or 25% of the total methane emissions; ref. 3). Globally, according to the most recent Intergovernmental Panel on Climate Change (IPCC) report, GHG emissions from agriculture represent around 10–12% (5.0–5.8 Gt CO₂ Eq/yr) of the total anthropogenic GHG emissions (1). In this report, livestock contribution to the global anthropogenic GHG emissions was estimated at 6.3%, with GHG emissions from enteric fermentation accounting for 2.1 Gt CO₂ Eq/yr and manure management accounting for 0.99 Gt CO₂ Eq/yr (1). The relative contribution of emissions from enteric fermentation to the total agricultural GHG emissions will vary by region depending on the structure of agricultural production and type of livestock production systems. For example, GHG from enteric fermentation were estimated at 57% for New Zealand, a country with a large, pasture-based livestock sector (4). Extensive research in recent years has provided a number of viable enteric methane mitigation practices, such as alternative electron receptors, methane inhibitors, dietary lipids, and increased animal productive efficiency (5). Methane emission in the reticulo-rumen is an evolutionary adaptation that enables the rumen ecosystem to dispose of hydrogen, a fermentation product and an important energy substrate for the methanogenic archaea (6), which may otherwise accumulate and inhibit carbohydrate fermentation and fiber degradation (7, 8). Some compounds may be effective in decreasing methane emission, but they may also decrease feed intake, fiber degradability, and animal productivity (5), or the rumen archaea may adapt to them (9). Therefore, it is important to evaluate methane mitigation strategies in long-term experiments, which for livestock experimentation requires treatment periods considerably longer than the 21–28 d, common for crossover designs. In addition, due to a variety of constraints and confounding factors of batch or continuous culture in vitro systems (5, 10), mitigation compounds, including methane inhibitors, have to be tested in vivo using animals with similar productivity to those on commercial farms. An example of the limitations of in vitro systems is a series of experiments with garlic oil. In continuous rumen culture, garlic oil was very effective in inhibiting rumen methane emission (11), but it failed to produce an effect in sheep (12). The nutrient requirements of high-producing dairy cows are much greater than those of nonlactating or low-producing cows (13) and hence any reduction in feed intake caused by a methane mitigation compound or practice would likely result in decreased productivity, which may not be evident in low-producing cows.Methane inhibitors are chemical compounds with inhibitory effects on rumen archaea. Compounds such as bromochloromethane, 2-bromoethane sulfonate, chloroform, and cyclodextrin have been tested, some successfully, in various ruminant species (5). Inhibition of methanogenesis by these compounds in vivo can be up to 60% with the effect of bromochloromethane shown to persist in long-term experiments (5, 14). However, the viability of these compounds as mitigation agents has been questioned due to concerns for animal health, food safety, or environmental impact. Bromochloromethane, for example, is an ozone-depleting agent and is banned in many countries.Among the efficacious methane inhibitors identified is 3-nitrooxypropanol (3NOP; ref. 15). This compound was part of a developmental program designing specific small molecule inhibitors for methyl coenzyme-M (CoM) reductase, the enzyme that catalyzes the last step of methanogenesis, the reduction of methyl CoM and coenzyme-B (CoB) into methane and a CoM–CoB complex (16). A continuous in vitro culture study (11) was followed by in vivo experiments in sheep (17), beef (18), and dairy cattle (19, 20), which demonstrated that 3NOP is an effective methane inhibitor. However, these experiments were conducted using nonlactating animals (17), or were short-term (<35 d; refs. 19 and 20). The rumen microorganisms have the ability to adapt to foreign agents or changes in the feeding regimen and, therefore, short-term responses are not representative of the effect of a given mitigation compound or practice in real farm conditions. McIntosh et al. (21), for example, showed that the MIC50 of essential oils doubled or tripled for a number of important rumen bacteria (Butyrivibrio fibrisolvens, Prevotella bryantii, Ruminococcus albus, Ruminobacter amylophilus), if they were adapted to the treatment for a period of 10 d. Thus, it is critically important for the success of GHG mitigation efforts to substantiate the mitigation potential of a given compound in long-term animal experiments before considering it for adoption by the livestock industries.     

Formamide reaction network in gas phase and solution via a unified theoretical approach: Toward a reconciliation of different prebiotic scenarios

Increasing experimental and theoretical evidence points to formamide as a possible hub in the complex network of prebiotic chemical reactions leading from simple precursors like H₂, H₂O, N₂, NH₃, CO, and CO₂ to key biological molecules like proteins, nucleic acids, and sugars. We present an in-depth computational study of the formation and decomposition reaction channels of formamide by means of ab initio molecular dynamics. To this aim we introduce a new theoretical method combining the metadynamics sampling scheme with a general purpose topological formulation of collective variables able to track a wide range of different reaction mechanisms. Our approach is flexible enough to discover multiple pathways and intermediates starting from minimal insight on the systems, and it allows passing in a seamless way from reactions in gas phase to reactions in liquid phase, with the solvent active role fully taken into account. We obtain crucial new insight into the interplay of the different formamide reaction channels and into environment effects on pathways and barriers. In particular, our results indicate a similar stability of formamide and hydrogen cyanide in solution as well as their relatively facile interconversion, thus reconciling experiments and theory and, possibly, two different and competing prebiotic scenarios. Moreover, although not explicitly sought, formic acid/ammonium formate is produced as an important formamide decomposition byproduct in solution.Very different environments have been suggested as possible cradles for the emergence of biomolecules, including a primordial liquid soup (1), rarified gaseous interstellar clouds (2, 3), liquid–solid interfaces at hydrothermal conditions (4), and the extreme case of impact sites of meteorites and comets (5). Biochemically relevant reactions can be fueled by a range of different energy sources, and a large number of possible chemical reactions and reaction paths are suggested to have played an important role in the process leading simple molecules to form small organic molecules and, from them, biological monomers and polymers.Among such small organic molecules, formamide is assuming an ever more central role in prebiotic chemistry research, as recently shown in experiments mimicking some of those origins of life scenarios, such as laser sparks (6), UV light (7), proton irradiation (8), or shock waves (as in meteorite impacts) (9). The main reason for such strong interest in formamide, besides its ubiquitousness in the solar system, is its chemical flexibility: it can be formed from (or, conversely, dissociated into) different molecular species that represent fundamental building blocks, including H₂, H₂O, NH₃, CO, HCN, HNCO, and HCOOH (10, 11). The barriers for these different processes lie in a relatively narrow range, providing many synthetic directions. Additionally, as has been also showed experimentally and computationally, formamide could give rise to all classes of biomolecular monomers, from amino acids to nucleic acids to sugars (12, 13).For example, inspired by the classic Miller experiments, recent ab initio MD (AIMD) simulations demonstrated that an intense electric field can induce the barrierless (spontaneous) formation of formamide and formic acid from a CH₄, CO, NH₃, H₂O, and N₂ mixture in the condensed phase, and under the same conditions, formamide in turn gives birth to more complex organic molecules including glycine (14). In this context, understanding the thermodynamics (free energy differences) and kinetics implied in basic reactions of prebiotic relevance is key to assess the likelihood of the different scenarios put forward in the literature. Computational approaches are a formidable complement to experiments in this field because they exploit the fundamental laws of quantum mechanics to study chemical reactions, interpret experimental results, and predict novel mechanisms.However, contemporary computational physical chemistry is dominated by gas-phase calculations at zero temperature, with effects due to temperature, pressure, and chemical environment relegated to approximated extrapolations. For instance, our knowledge of reaction dynamics in condensed phases is far from complete (15, 16), despite the fact that water is a polyvalent molecule, known to participate also in formamide chemistry under different roles, including as a stabilizer through hydrogen bonds, as an efficient acid–base bifunctional catalyst, and as a coreactant (17). Additional effects should also be considered, including vibrational energy dissipation upon birth of exothermic products or solute trapping into finite-lifetime cages affecting its diffusion and reactivity (16, 18, 19). The large number of possible configurations [already including few water molecules (17)] together with the strong anharmonicity of liquids naturally calls for methods like MD that include from the start the finite-temperature dynamics. From a prebiotic perspective, it is necessary to have a comparative understanding of reaction networks in different environments (gas or condensed phase, with different solvents and also interfaces with minerals) and at different conditions (T, P, irradiation, shock waves, etc.), eventually embracing also nonequilibrium scenarios, for their role in the emergence of life.The overwhelming gap between the (long) time scale of reactive events and the (short) time scale of ab initio MD simulations can be effectively overcome using the available enhanced sampling techniques, including metadynamics (20) and transition path sampling (21). Despite this, the widespread adoption of MD simulations in the study of chemical reactions has so far been slowed down by the lack of standard, general purpose formulations of reaction coordinates. In particular, it is challenging to design coordinates that fully include the important role of the solvent degrees of freedom (22–24) and that are general enough to be applied to a palette of diverse reaction mechanisms.Here we propose a novel free energy calculation approach able to address in a general way a wide range of chemical reaction mechanisms in solution. The method deals in the same formal way (namely, in the same space of coordinates) with gas-phase and solutions, allowing for the first time to our knowledge a direct comparison of the two environments and an easy assessment of the effects of a given solvent on reaction pathways. We exploit the unique advantages of our new approach to reconstruct in detail the multiple formation/decomposition mechanisms of formamide and to disclose the sizable qualitative and quantitative difference of solution chemistry with respect to gas phase. In this way we unveil a reaction network of remarkable complexity that sheds further light on fundamental prebiotic reactions and will serve as the basis of a future comparative understanding of different scenarios for the emergence of biological molecules.