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Macronutrients
Published in Chuong Pham-Huy, Bruno Pham Huy, Food and Lifestyle in Health and Disease, 2022
Chuong Pham-Huy, Bruno Pham Huy
Fibrous or fibrillar proteins are filiform, long and physically tough. They are mainly of animal origin and are insoluble in all common solvents such as water, acid, alkali solution and organic solvents. Fibrous proteins have structural and protective functions. The fibrous proteins are extremely strong and possess the elastomer characteristics. It is a heterogeneous group and includes the keratins and the proteins of connective tissues found in bones, skin, hair, nails, horns, hoofs, wool, and silk (36, 47). The important examples are: collagens, elastins, keratins, and fibroins. Collagens and their analogs elastins are the proteins of connective tissues, skin, cornea of the eyes, tendons, cartilages, and ligaments. They are also called ‘cellular glue’ as they help give tissues their shape and keep them strong, and are the major proteins of white connective tissues (tendons, cartilage) and of bone. Due to its abundance, strength and its directly proportional relation with skin aging, collagen has gained great interest in the cosmetic industry (51). Elastin has the additional property of being elastic as a rubber band (47). Keratins are rich in cystine, a sulfur amino acid, and are the major components of skin, hair, feathers, hoofs, nails, and horns (47). Fibroins are mainly composed of amino acids; glycine, alanine, and serine and are found in the fibers of silk (47). Fibrin is the protein formed when blood clots.
Specific Management of PPH
Published in Gowri Dorairajan, Management of Normal and High Risk Labour During Childbirth, 2022
The profile in suspected cases includes prothrombin time, activated partial thromboplastin, and platelet count. In the obstetric setting of bleeding, especially in abruption and severe preeclampsia, bedside point of care clot retraction time helps in knowing the capacity to clot and the ability of clot to retract to leave clear serum within 30 minutes of clotting. When the blood does not clot well or does not leave behind clear serum, one should suspect that there is ongoing fibrinolysis where the clot retraction does not leave behind clear serum. Fibrin production can be indirectly measured by assessing the levels of fibrin degradation product D-Dimer. Fibrinogen level assay also reflects DIC, though it is less specific. Fibrinogen levels give clinical guidance to the component transfusion. Thromboelastography (TEG) is an objective method of studying coagulation, but the experience of its use in obstetrics haemorrhage is limited in the literature.
Primary Postpartum Haemorrhage
Published in Sanjeewa Padumadasa, Malik Goonewardene, Obstetric Emergencies, 2021
Sanjeewa Padumadasa, Malik Goonewardene
The haemoglobin level (obtained by a bedside hemoCue) can be misleadingly normal in cases of acute haemorrhage. Therefore, the infusion of fluids, including blood, is best guided by a combination of the clinical picture and laboratory results. Fibrin degradation products (FDP) and D-dimers, which are end products of fibrinolysis, need to be assayed if DIC is suspected. There is no single laboratory test for the diagnosis of DIC. The PT - INR and APTT are reduced to the lower end of the normal range, and fibrinogen levels are increased in pregnancy. Therefore, a significant amount of blood could be lost before changes are evident in these tests.
Visual Observation of Abdominal Adhesion Progression Based on an Optimized Mouse Model of Postoperative Abdominal Adhesions
Published in Journal of Investigative Surgery, 2023
Zijun Wang, Enmeng Li, Cancan Zhou, Bolun Qu, Tianli Shen, Jie Lian, Gan Li, Yiwei Ren, Yunhua Wu, Qinhong Xu, Guangbing Wei, Xuqi Li
PAA formation is essentially peritoneal overrepair. Qiongyuan Hu et al [14] confirmed that the macrophage–myofibroblast transition (MMT) and the progressive migration of fibroblasts during adhesion formation enhanced the formation of collagen in the adhesion tissue. In the early stage, a large amount of prothrombin is activated to form thrombin after the coagulation process begins, which in turn activates fibrinogen to form fibrin. The fibrin then coagulates with platelets around the wound surface to form a fibrin mesh. Subsequently, the rate of fibrinolysis decreases during adhesion formation, resulting in progressive collagen deposition. We demonstrated that collagen and fibrin formation began on POD 1 and gradually increased until it remained stable on POD 7, which is largely consistent with the pattern of development. In addition, the expression of macrophage-related genes, such as Aif1 and Tyrobp, was significantly increased on POD 7. Aif1 may promote vascular smooth muscle growth and regulate the FGF production pathway [27, 28], which is involved in angiogenesis [25, 29, 30]. Therefore, we speculated that Aif1 may affect the fibrinolytic process and vascular formation during the late stage of PAA formation. However, the role of these genes in the pathogenesis of PAAs remains to be further investigated.
Therapeutic effects and mechanism of human amnion-derived mesenchymal stem cells on hypercoagulability in a uremic calciphylaxis patient
Published in Renal Failure, 2023
Anning Bian, Xiaoxue Ye, Jing Wang, Ming Zeng, Jiayin Liu, Kang Liu, Song Ning, Yugui Cui, Shaowen Tang, Xueqiang Xu, Yanggang Yuan, Zhonglan Su, Yan Lu, Jing Zhou, Xiang Ma, Guang Yang, Yaoyu Huang, Feng Chen, Youjia Yu, Mufeng Gu, Xiaolin Lv, Ling Wang, Jing Zhao, Xiuqin Wang, Ningxia Liang, Changying Xing, Lianju Qin, Ningning Wang
D-dimer is a plasmin-derived soluble degradation product of cross-linked fibrin, served as a valuable marker of coagulation and fibrinolysis activation. Of note, D-dimer is a sensitive indicator for detection of thrombosis, but its specificity is not ideal [24]. Fibrinogen, the soluble precursor of fibrin, is a major determinate of blood viscosity and red blood cells aggregation. Elevated fibrinogen levels may provide a hypercoagulable state through increasing the aggregation and reactivity of platelet [25]. Prior to hAMSC treatment, the patient in this case had elevated levels of plasma D-dimer and fibrinogen, indicative of an underlying hypercoagulable condition. The patient also displayed significantly elevated levels of CRP and leukocytes before hAMSC administration, indicating a high inflammatory status. Increasing evidence indicates that systemic inflammation can induce the activation of coagulation system, which may result from tissue factor (TF)-mediated thrombin generation or the dysfunction of anticoagulant pathway, such as the impaired protein C system [26]. Compared with physiological serum level of albumin, platelet aggregation was significantly higher in the presence of low serum albumin level [27]. This case had hypoalbuminaemia at the onset of hAMSC administration. Thus, either acquired thrombophilic conditions like protein C and protein S deficiency or hypercoagulability induced by inflammation and hypoalbuminaemia may be correlated with the development of CUA.
Exploring the pathways of inflammation and coagulopathy in COVID-19: A narrative tour into a viral rabbit hole
Published in International Reviews of Immunology, 2022
Nitsan Landau, Yehuda Shoenfeld, Liat Negru, Gad Segal
Notwithstanding to all of the above, COVID-19 patients are partially resistant to anticoagulation. Several mechanisms have been proposed, for example, anti-thrombin deficiency as previously described that can result in heparinoid resistance. This is explained, in part, by concurrent extravascular clotting and fibrin deposition evading endovascular anticoagulants. Indeed, coagulation and fibrinolysis do not always occur merely within the vascular space, especially in the lungs. One prominent feature of airway inflammation is leakage of plasma proteins including fibrinogen and thrombin into the airway lumen. Extravascular thrombin can convert fibrinogen into fibrin. The physiological purpose of this extravascular fibrin is presumably serving as a matrix on which inflammatory cells can attach and function, similarly to the intravascular activity of NETs. Extravascular fibrin breakdown also explain the marked increase in D‐dimer noted in patients with malignancies even in the absence of clots within the circulation. Accordingly, extravascular fibrinolysis may be relevant to COVID‐19. The intense lung inflammation is associated with elevated fibrinogen levels. Cross‐linked fibrin generated from the markedly increased fibrinogen that leak into the extravascular space would be broken down by plasmin or proteolytic enzymes released from activated neutrophils. D‐dimer formed in this manner may not signify thrombus formation but could predict the need for mechanical ventilation, arising from lung exudates [65].