Model of the mode of action of Cry and Cyt toxins. Panel A, sequential interaction of Cry toxins with different receptor molecules in lepidopteran larvae. (1) Solubilization and activation of the toxin; (2). Binding of monomeric Cry toxin to the first receptor (CADR or GCR), conformational change is induced in the toxin and α-helix 1 is cleaved; (3) Oligomer formation; (4) Binding of oligomeric toxin to second receptor (GPI-APN or GPI-ALP), a conformational change occurs and a molten globule state of the toxin is induced; (5) insertion of the oligomeric toxin into lipid rafts and pore formation. Panel B, role of Cyt and Cry toxins in the intoxication of dipteran larvae. (1) Cry and Cyt toxins are solubilized and activated; (2) Cyt toxin inserts into the membrane and Cry toxin binds to receptors located in the membrane (ALP or Cyt toxin); (3) oligomerization of the Cry toxin is induced; (4) oligomer is inserted into the membrane resulting in pore formation.
Raynaud's phenomenon is due to transient cessation of blood flow to the digits of the hands or feet. An attack of Raynaud's phenomenon is classically manifested as triphasic color changes. The white phase is due to excessive vasoconstriction and cessation of regional blood flow. This phase is followed by a cyanotic phase, as the residual blood in the finger desaturates. The red phase is due to hyperemia as the attack subsides and blood flow is restored. An attack is frequently associated with pain and/or paresthesia due to sensory nerve ischemia. Variants of Raynaud's phenomenon include acrocyanosis and primary livedo reticularis, each of which is associated with reduced skin blood flow, exacerbated by cold or emotional upset. Raynaud's phenomenon in the absence of other disorders is primary Raynaud's phenomenon, or Raynaud's disease. The mechanisms of Raynaud's disease include increased activation of the sympathetic nerves, in response to cold or emotion; an impaired habituation of the cardiovascular response to stress may contribute. In addition, there appears to be a local fault, which is likely multifactorial. This local fault is due to an alteration in vascular function rather than vascular structure. The alteration in vascular function may be related to increased sensitivity to cold of the adrenergic receptors on the digital artery vascular smooth muscle. In some cases, locally released or systemically circulating vasoconstrictors may participate, including endothelin, 5-hydroxytryptamine and thromboxane. A deficiency or increased degradation of nitric oxide, possibly due to increased oxidative stress, may be involved in some cases. These recent pathophysiological insights may lead to new therapeutic options.
In mice, CFD is linked to pronounced platelet activation, depicted by higher GPIIb/IIIa surface expression in wild-type mice. This might be of clinical importance since high CFD plasma concentrations were also associated with increased mortality in sepsis patients.
During systemic infections, the complement and coagulation system are tightly networking proteolytic cascades . (1) Platelets and platelet-microparticles (PMP) are able to activate classical and terminal complement activation pathways [6, 7]. (2) Thrombin cleaves C5 through terminal complement activation . (3) FXa, FXIa, and plasmin function as C3 and C5 convertase . In addition, platelet adhesion to injured endothelial cells is promoted by the activated coagulation and complement system , i.e., the anaphylatoxin C5a induces tissue factor (TF) activity in human endothelial cells . In turn, activated platelets mediate complement activation via P-selectin (CD62P) expression [12, 13]. Such interactions may also contribute to thrombosis and thrombocytopenia .
One serine protease of the alternative complement activation pathway is the complement factor D (CFD). CFD is stored in human platelets and is released after stimulation with ADP, collagen or thrombin . The blockade of CFD with an anti-factor D antibody inhibits platelet activation by reduced CD62P expression on the platelet surface . Otherwise, the physiological function of CFD in platelets and its role in coagulation during infection remains unclear. Based on the literature above, we designed a translational study in both mice and men to address the impact of CFD on coagulation in sepsis. We hypothesize (1) that CFD impacts coagulopathy in mice with systemic infection; (2) that CFD interaction with coagulation is associated with outcome in sepsis patients, and (3) that antiplatelet drugs affect the CFD level in patients with sepsis.
The study was conducted in accordance with Helsinki Declaration and approved by the local ethical committee of Jena University Hospital (474403/16). Plasma samples were collected from ICU patients between 2001 and 2005.
While the crosslink between coagulation and complement system is well established [3,4,5, 7, 10,11,12,13, 23], the impact of CFD on the coagulation cascade is still unclear. It is known that CFD is localized in human platelets . Our data add important insights regarding the functional role: an enhanced thrombin generation reflected by higher TAT complex concentration in CFD-deficient mice is not only linked to compensatory C5a formation during sepsis, but also contributes to abnormal coagulation activity. Thrombin is known as a potent platelet activator and initiates GPIIb/IIIa expression on thrombocytes . Interestingly, the surface receptor expression of GPIIb/IIIa was significantly reduced in CFD-deficient mice, while we observed an increase in thrombocyte surface markers in wild-type mice. Other markers of coagulation such as the results of ROTEM (clotting time, maximal clot firmness) or D-dimer were affected in CFD-deficient as well as in wild-type mice. So, during infection CFD significantly impacts the inflammation-triggered activation of the coagulation cascade in mice, which was found in wild-type mice by pronounced surface expression of GPIIb/IIIa, P-selectin and the decrease of platelets and hint to the hypercoagulable state during sepsis.
In humans, we found high CFD levels in non-survivors of the whole study population and selectively in sepsis patients. These high CFD levels represent a strong activation of the alternative pathway. Alternative complement activation acts as an amplification loop triggering the hyperactive inflammatory response and thereby contributing negatively to the progression of the disease [18, 28,29,30]. Furthermore, CFD is a modulator of complement activation during infection affecting the innate immune response . This might be the reason why a high CFD generation as observed in our study was associated with a high in-hospital mortality. Further, the positive correlation between SOFA score and CFD would suggest a negative effect regarding (multi-)organ dysfunction in patients with strongly elevated CFD plasma level. An important aspect to monitor disease severity is to identify the individual patient risk based on diagnosis, co-morbidity and previous surgical procedures in the light of activation of coagulation and immune responses. An increased C3 and C4 consumption in sepsis, found by inversely lower C3 and C4 levels in patient plasma, is more often associated with unfavorable outcome . Complement activation as an indicator of hospital acquired infection has a strong impact on mortality and hospital stay. Also, the depletion of complement C3 was found to be connected to poor prognosis in severe abdominal sepsis .
Our data indicate that the alternative complement pathway interacts with immune processes and coagulation during infection and inflammation. Factor D seems to play a crucial role in this interaction during sepsis. Other authors focused on terminal complement activation and the lectin pathway. High C3, MAC, and MBL serum concentrations are predictive for sepsis-induced disseminated intravascular coagulation .
The crosslink between complement and coagulation cascades seems to be permanently present in the course of systemic inflammation. In mice, CFD is linked to pronounced platelet activation, depicted by higher surface expression on thrombocytes in sepsis. In humans, CFD revealed significant impact on in-hospital mortality and predicts disease severity and poor outcome shown by high factor D level in the non-survivor group. The impact of antiplatelet drugs to improve sepsis might be beneficial and affect CFD plasma level and patient outcome.
For over 30 years, the MODFLOW program has been widely used by academics, private consultants, and government scientists to accurately, reliably, and efficiently simulate groundwater flow. With time, growing interest in surface and groundwater interactions, local refinement with nested and unstructured grids, karst groundwater flow, solute transport, and saltwater intrusion, has led to the development of numerous MODFLOW versions. Although these MODFLOW versions are often based on the core MODFLOW version (previously MODFLOW-2005), there are often incompatibilities that restrict their use with other MODFLOW versions. In many cases, development of these alternative MODFLOW versions has been challenging due to the underlying program structure, which was designed for the simulation of a single groundwater flow model using a regular MODFLOW grid consisting of layers, rows, and columns.
MODFLOW 6 is an object-oriented program and framework developed to provide a platform for supporting multiple models and multiple types of models within the same simulation. This version of MODFLOW is labeled with a "6" because it is the sixth core version of MODFLOW to be released by the USGS (previous core versions were released in 1984, 1988, 1996, 2000, and 2005). In the new design, any number of models can be included in a simulation. These models can be independent of one another with no interaction, they can exchange information with one another, or they can be tightly coupled at the matrix level by adding them to the same numerical solution. Transfer of information between models is isolated to exchange objects, which allow models to be developed and used independently of one another. Within this new framework, a regional-scale groundwater model may be coupled with multiple local-scale groundwater models. Or, a surface-water flow model could be coupled to multiple groundwater flow models. The framework naturally allows for future extensions to include the simulation of solute transport. 2b1af7f3a8