Approaches in biotechnological applications of natural polymers

Natural polymers, such as gums and mucilage, are biocompatible, cheap, easily available and non-toxic materials of native origin. These polymers are increasingly preferred over synthetic materials for industrial applications due to their intrinsic properties, as well as they are considered alternative sources of raw materials since they present characteristics of sustainability, biodegradability and biosafety. As definition, gums and mucilages are polysaccharides or complex carbohydrates consisting of one or more monosaccharides or their derivatives linked in bewildering variety of linkages and structures. Natural gums are considered polysaccharides naturally occurring in varieties of plant seeds and exudates, tree or shrub exudates, seaweed extracts, fungi, bacteria, and animal sources. Water-soluble gums, also known as hydrocolloids, are considered exudates and are pathological products; therefore, they do not form a part of cell wall. On the other hand, mucilages are part of cell and physiological products. It is important to highlight that gums represent the largest amounts of polymer materials derived from plants. Gums have enormously large and broad applications in both food and non-food industries, being commonly used as thickening, binding, emulsifying, suspending, stabilizing agents and matrices for drug release in pharmaceutical and cosmetic industries. In the food industry, their gelling properties and the ability to mold edible films and coatings are extensively studied. The use of gums depends on the intrinsic properties that they provide, often at costs below those of synthetic polymers. For upgrading the value of gums, they are being processed into various forms, including the most recent nanomaterials, for various biotechnological applications. Thus, the main natural polymers including galactomannans, cellulose, chitin, agar, carrageenan, alginate, cashew gum, pectin and starch, in addition to the current researches about them are reviewed in this article.. }To the Conselho Nacional de Desenvolvimento Cientfíico e Tecnológico (CNPq) for fellowships (LCBBC and MGCC) and the Coordenação de Aperfeiçoamento de Pessoal de Nvíel Superior (CAPES) (PBSA). This study was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BIO/04469/2013 unit, the Project RECI/BBB-EBI/0179/2012 (FCOMP-01-0124-FEDER-027462) and COMPETE 2020 (POCI-01-0145-FEDER-006684) (JAT)

Вологозберігаючі та паропроникні властивості ранозаживляючих нановмісних біорозчинних полімерів

The problem of purulent wounds makes searching new medicinal, physical-chemical and physical methods of soft tissues purulent diseases treatment. The main requirements for modern wound healing coatings except their safety characteristics for protecting wound against infection, include their good elasticity, moisture retaining, vapor and gas permeability as well as their absorbing capacity. One of the modern approaches in wound infection treatment is the use of antimicrobial products containing nano particles of silver oxide, copper, iron, zinc, magnesium and other metals. We have developed a biodegradable polymer basis ‘Biodep’ (utility patent application is № u 2016 04649) and biodegradable polymer film ‘Biodep-nano’, which is saturated with zinc nano oxide for wounds treatment of various origins (utility patent application is № u 2016 05502) and under in vitro conditions gravimetric methods were used to study the developed polymers’ moisture retaining, vapor and gas permeability characteristics at different temperatures. The obtained results revealed that the developed biodegradable polymers have good vapor permeability and excellent moisture transmission. Vapor permeability of biodegradable polymer based film and of the film with 5% zinc nano oxide concentration was virtually identical, but at 37° C films vapor permeable characteristics increased greatly. The obtained results indicate that the developed polymers have high moisture retaining, vapor and gas permeability characteristics, what is essential to modern coating materials in wounds treatment of various origins.О проблеме лечения гнойных ран cвидетельствует появление новых медикаментозных, физико-химических и физических методов лечения гнойных заболеваний мягких тканей. Среди основных требований, предъявляемых к современным раневым покрытиям, кроме функции защиты раны от инфицирования, есть хорошая эластичность, парогазопроницаемость и сорбционные способности. Одними из современных тенденций в борьбе с раневой инфекцией является применение противомикробных средств, содержащих наночастицы оксидов серебра, меди, железа, цинка, магния и других металлов. Нами разработана биоразлагаемая полимерная основа «Биодеп» (номер заявки о выдаче патента на полезную модель u 2016 04649) и биоразлагаемая полимерная пленка «Биодепнано», которая насыщена нанооксидом цинка для лечения ран различного генеза (номер заявки о выдаче патента на полезную модель u 2016 05502) и в условиях in vitro с помощью гравиметрических методов проводилось изучение паропроницаемых и влагопроницаемых свойств разработанных полимеров в различных температурных условиях. По данным полученных результатов установлено, что разработанные нами биоразлагаемые полимерные материалы обладают хорошей паропроницаемостью и влагопроницаемостью. Паропроницаемые свойства биоразлагаемые полимерной основы и пленки с 5% концентрацией нанооксидов цинка практически не отличаются, а при температуре 37° С паропроницаемые свойства пленок значительно повышаются. Полученные результаты свидетельствуют о сбережении влаги, паропроницаемых и влагопроницаемых свойствах разработанных полимеров, что важно для современных покрытий в лечении ран различного генеза.Про проблему лікування гнійних ран свідчить поява нових медикаментозних, фізико-хімічних і фізичних методів лікування гнійних захворювань м'яких тканин. Серед основних вимог, що пред'являються до сучасних ранових покриттів, крім функції захисту рани від інфікування, є добра еластичність, парогазопроникність та сорбційна здатність. Одними із сучасних тенденцій у боротьбі з рановою інфекцією є застосування протимікробних засобів, що містять наночастинки оксидів срібла, міді, заліза, цинку, магнію та інших металів. Нами розроблена біодеградуюча полімерна основа «Біодеп» (номер заявки про видачу патенту на корисну модель u 2016 04649) та біодеградуюча полімерна плівка «Біодеп-нано», яка насичена нанооксидом цинку для лікування ран різного генезу (номер заявки про видачу патенту на корисну модель u 2016 05502) та в умовах in vitro за допомогою гравіметричних методів проводилося вивчення паропропускної та вологопропускної здатності розроблених полімерів за різних температурних умов. За даними отриманих результатів встановлено, що розроблені нами біодеградуючі полімерні матеріали володіють доброю паропроникністю та відмінно пропускають вологу. Паропроникність біодеградуючої полімерної основи та плівки з 5 % концентрацією нанооксиду цинку фактично не відрізняються, а при температурі 37° С паропроникаючі властивості плівок значно підвищуються. Отримані результати свідчать про вологозберігаючі, паропроникні та вологопроникні властивості розроблених полімерів, що є важливим для сучасних покривних матеріалів у лікуванні ран різного генезу

Iatrogenic Pseudoaneurysms of the Extrahepatic Arterial Vasculature: Management and Outcome

Background. Pseudoaneurysms of the extrahepatic arterial vasculature are relatively uncommon lesions following surgery and trauma. In this report we analyze the presentation, management and outcomes of these vascular lesions. Of the related surgical procedures, the reported incidence is highest following laparoscopic cholecystectomy. We hereby analyze the literature on this subject and report our experience, specifically with extrahepatic pseudoaneurysms, drawing an important distinction from intrahepatic pseudoaneurysms. Methods. From September 1995 until July 2004, six patients, including three males and three females with a mean age of 67 years, were treated for seven extrahepatic arterial pseudoaneurysms. Patients were evaluated by endoscopy, ultrasound, computerized tomography, and angiography. Management included coil embolization or arterial ligation and/or hepatic resection. Results. The mean pseudoaneurysm size was 4.9-cm (range 1.0–11.0-cm) and the locations included the right hepatic artery (n = 5), inferior pancreaticoduodenal artery (n = 1), and gastroduodenal artery (n = 1). All six patients had prior surgical or percutaneous procedures. Median latency period between the original procedure and treatment of pseudoaneurysm was 17 weeks (range one month–16 years). Clinical features ranged from the dramatic presentation of hypotension secondary to intraperitoneal aneurysmal rupture to the subtle presentation of obstructive jaundice secondary to pseudoaneurysm mass effect. The range of patient presentations created diagnostic challenges, proving that accurate diagnosis is made only by early consideration of pseudoaneurysm. Management was ligation of the right hepatic artery (n = 4) and embolization of the pseudoaneurysms (n = 2). Post-treatment sequelae included liver failure requiring liver transplant (n = 1), intrahepatic biloma requiring percutaneous drainage (n = 1) and cholangitis with right hepatic duct strictures requiring right lobectomy and biliary reconstruction (n = 1). These complications followed arterial ligation, with no complications resulting from embolization. All six patients are alive and well after a mean follow-up of 53 months. Conclusions. Our six patients demonstrate the diversity and unpredictability with which a pseudoaneurysm of the extrahepatic arterial vasculature may present in terms of initial symptoms, prior procedures, and the latency period between presentation and prior procedure. Through our experience and an analysis of the literature, we recommend a diagnostic and management approach for these patients

Differentiation Therapy Targeting the β-Catenin/CBP Interaction in Pancreatic Cancer

Background: Although canonical Wnt signaling is known to promote tumorigenesis in pancreatic ductal adenocarcinoma (PDAC), a cancer driven principally by mutant K-Ras, the detailed molecular mechanisms by which the Wnt effector β-catenin regulates such tumorigenesis are largely unknown. We have previously demonstrated that β-catenin’s differential usage of the Kat3 transcriptional coactivator cyclic AMP-response element binding protein-binding protein (CBP) over its highly homologous coactivator p300 increases self-renewal and suppresses differentiation in other types of cancer. Aim/methods: To investigate Wnt-mediated carcinogenesis in PDAC, we have used the specific small molecule CBP/β-catenin antagonist, ICG-001, which our lab identified and has extensively characterized, to examine its effects in human pancreatic cancer cells and in both an orthotopic mouse model and a human patient-derived xenograft (PDX) model of PDAC. Results/conclusion: We report for the first time that K-Ras activation increases the CBP/β-catenin interaction in pancreatic cancer; and that ICG-001 specific antagonism of the CBP/β-catenin interaction sensitizes pancreatic cancer cells and tumors to gemcitabine treatment. These effects were associated with increases in the expression of let-7a microRNA; suppression of K-Ras and survivin; and the elimination of drug-resistant cancer stem/tumor-initiating cells