Alpha-synuclein (α-syn) is localized in cellular organelles of most neurons, but many of its physiological functions are only partially understood. α-syn accumulation is associated with Parkinson's ...disease, dementia with Lewy bodies, and multiple system atrophy as well as other synucleinopathies; however, the exact pathomechanisms that underlie these neurodegenerative diseases remain elusive. In this review, we describe what is known about α-syn function and pathophysiological changes in different cellular structures and organelles, including what is known about its behavior as a prion-like protein. We summarize current knowledge of α-syn and its pathological forms, covering its effect on each organelle, including aggregation and toxicity in different model systems, with special interest on the mitochondria due to its relevance during the apoptotic process of dopaminergic neurons. Moreover, we explore the effect that α-syn exerts by interacting with chromatin remodeling proteins that add or remove histone marks, up-regulate its own expression, and resume the impairment that α-syn induces in vesicular traffic by interacting with the endoplasmic reticulum. We then recapitulate the events that lead to Golgi apparatus fragmentation, caused by the presence of α-syn. Finally, we report the recent findings about the accumulation of α-syn, indirectly produced by the endolysosomal system. In conclusion, many important steps into the understanding of α-syn have been made using
and
models; however, the time is right to start integrating observational studies with mechanistic models of α-syn interactions, in order to look at a more complete picture of the pathophysiological processes underlying α-synucleinopathies.
Dysfunction of cellular homeostasis can lead to misfolding of proteins thus acquiring conformations prone to polymerization into pathological aggregates. This process is associated with several ...disorders, including neurodegenerative diseases, such as Parkinson's disease (PD), and endoplasmic reticulum storage disorders (ERSDs), like alpha-1-antitrypsin deficiency (AATD) and hereditary hypofibrinogenemia with hepatic storage (HHHS). Given the shared pathophysiological mechanisms involved in such conditions, it is necessary to deepen our understanding of the basic principles of misfolding and aggregation akin to these diseases which, although heterogeneous in symptomatology, present similarities that could lead to potential mutual treatments. Here, we review: (i) the pathological bases leading to misfolding and aggregation of proteins involved in PD, AATD, and HHHS: alpha-synuclein, alpha-1-antitrypsin, and fibrinogen, respectively, (ii) the evidence linking each protein aggregation to the stress mechanisms occurring in the endoplasmic reticulum (ER) of each pathology, (iii) a comparison of the mechanisms related to dysfunction of proteostasis and regulation of homeostasis between the diseases (such as the unfolded protein response and/or autophagy), (iv) and clinical perspectives regarding possible common treatments focused on improving the defensive responses to protein aggregation for diseases as different as PD, and ERSDs.
Peripheral blood mononuclear cells (PBMCs) contain a cell fraction of mononuclear progenitor cells (MPCs), which own significant angiogenic potential. Autologous transplant of PBMC and/or ...platelet‐rich plasma (PRP) promotes endothelial cells differentiation in experimental lower limb ischemia, which is considered a safe and effective strategy to support revascularization, either in animal models or clinical trials. In addition, thrombin has been proposed to enrich biological scaffolds, hence increasing MPC viability after intramuscular administration, whereas proangiogenic mediators such as vascular endothelial growth factor (VEGF), tumor necrosis factor alpha (TNF‐α), inhibitor of the plasminogen activator‐1 (PAI‐1), and chemokine (CXCL1; GRO‐α) participate in the endothelial response to ischemia, through their proangiogenic effects over endothelial cells proliferation, survival, migration, endothelial integrity maintenance, and physiologic vascular response to injury. In the present study, we describe the effect of autologous PBMCs transplant and PRP, either with or without thrombin, over proangiogenic mediators (measured by enzyme‐linked immunosorbent assay) and revascularization response (angiographic vascular pattern at 30 days after vascular occlusion) in a rat model of lower limb ischemia. The group treated with PBMC + PRP significantly induced PAI‐1, an effect that was prevented by the addition of thrombin. Furthermore, treatment with PBMC + PRP + thrombin resulted in the induction of VEGF. GRO‐α showed a sensitive induction of all proangiogenic mediators. All treatments significantly stimulated revascularization, according to angiographic assessment, whereas higher effect was observed with PBMC + PRP treatment (p < .0001). In conclusion, autologous PBMC transplant stimulates revascularization during experimental ischemia of the lower limb, whereas particular effects over proangiogenic and fibrinolytic mediators may be attributed to PBMCs and its combination with PRP and thrombin.
Updates in Mirizzi syndrome Valderrama-Treviño, Alan Isaac; Granados-Romero, Juan José; Espejel-Deloiza, Mariana ...
Hepatobiliary surgery and nutrition,
06/2017, Volume:
６, Issue:
３
Journal Article
Open access
Mirizzi syndrome, known as extrinsic bile compression syndrome, is a rare complication of cholecystitis and chronic cholelithiasis, secondary to the obliteration of the infundibulum of the ...gallbladder or cystic duct caused by the impact of one or more calculations in these anatomical structures, which leads to compression of the adjacent bile duct, resulting in partial or complete obstruction of the common hepatic duct, triggering liver dysfunction. Our aim is to identify and describe the current epidemiology, diagnostic methods, and treatment of Mirizzi syndrome. A literature search was performed using different databases, including Medline, Cochrane, Embase, Medscape, PubMed, using keywords: Mirizzi syndrome, epidemiology, markers, pathophysiology, clinical presentation, diagnosis, and treatment. Selected original articles, review articles or case reports from 1997 to 2015 were collected, written in English or Spanish. The endoscopic retrograde cholangiopancreatography (ERCP) is the most accurate diagnostic method. The traditional treatment has been surgery and involves an incision at the bottom of the gallbladder and calculus removal. If fistulas are observed, it is performed a partial cholecystectomy; otherwise, a cholecystocholedochoduodenostomy is an alternative. Endoscopic treatment includes biliary drainage and stone extraction. Many surgeons claim that laparoscopic cholecystectomy is contraindicated in Mirizzi syndrome because of the presence of inflammatory tissue and adhesions in the Calot’s triangle. If dissection is attempt, it can cause unnecessary injury to the bile duct. However, other surgeons consider the laparoscopic approach is feasible, although technically challenging. Currently, laparoscopic cholecystectomy for this condition is considered controversial and technically challenging; however, it has shown that with the right skills and equipment, it is a safe and feasible way to treat some cases of Mirizzi syndrome type I and II.
Objective
To describe and clarify management protocols in relation to spontaneous pneumomediastinum, and try to integrate criteria on this subject.
Background
Thoracic physicians are faced with ...patients who present with gas in the mediastinum, frequently without an obvious etiologic factor. Published material contains heterogeneous information from which different conclusions can be drawn.
Methods
In a Medline search from 1990 to 2012, we collected data on mortality, morbidity, signs, symptoms, etiologic factors, and diagnostic methods. Standardized mean differences were calculated.
Results
We identified 600 patients in 27 papers with series of >5 patients without precipitating or etiologic factors previous to the clinical presentation, but athletic activity, drug abuse, and history of asthma played an apparent role in the disease process. Most patients complained of thoracic pain and dyspnea, with subcutaneous emphysema and Hamman’s sign. The most common complication was tension pneumothorax. Morbidity was seen in 2.8%; no mortality has been reported so far.
Conclusion
Spontaneous pneumomediastinum is a rare disease with a benign course, which should be treated conservatively unless a complication mandates an invasive procedure. An algorithm for diagnosis and treatment is offered, based on the available evidence.
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