Влияние стадий обработки волокон лубяных культур на показатели микрокристаллической целлюлозы

Досліджено процес одержання мікрокристалічної целюлози із волокон недеревної рослинної сировини (льону, конопель, кенафу) з використанням кислотного передгідролізу, лужно-сульфітно-спиртового способу делігніфікації та окиснювально-органосольвентної обробки. Встановлено, що проведення кислотного передгідролізу на першій стадії одержання мікрокристалічної целюлози дає змогу значно зменшити вміст мінеральних речовин (на 62—75 %), частково вихід волокнистого напівфабрикату (на 9—12 %)і вміст залишкового лігніну (на 20—30 %) порівняно з вихідною сировиною. Проведення органосольвентної делігніфікації зменшує до 1 % вміст залишкового лігніну в целюлозах з усіх досліджених волокон. Скорочено кількість стадій технологічного процесу одержання мікрокристалічної целюлози за рахунок об’єднання процесів вибілювання та гідролізу органосольвентної целюлози із волокон луб’яних культур з використанням суміші розчинів оцтової кислоти та пероксиду водню концентрацією 35 і 30 % відповідно. Одержана мікрокристалічна целюлоза із волокон луб’яних рослин відповідає вимогам стандарту і рекомендується для використання на фармацевтичних підприємствах як наповнювач для виготовлення лікарських пігулок.The process of obtaining microcrystalline cellulose from non-wood plant bast fibers (flax, hemp, kenaf) with using preliminary acid hydrolysis, alkaline sulfite -alcohol method delignification and oxidation-organosolvent processing was investigated. It is established that the conduct preliminary acid hydrolysis in the first step of obtaining microcrystalline cellulose can significantly reduce the mineral content (at 62—75 %), partly yield of pulp (at 9—12 %) and residual lignin content (at 20—30 %) compared of feedstock. Carrying out of organosolvent delignification reduces to 1 % content of residual lignin in the pulp of all studied fibers. Reduced the number of stages of the technological process of microcrystalline cellulose by combining the processes of bleaching and hydrolysis of organosolvent cellulose from plant bast fibers with using a mixture of acetic acid and hydrogen peroxide concentration of 35 and 30 %, respectively. The resulting microcrystalline cellulose from plant bast fibers meets the standard and is recommended for use in pharmaceutical companies as a filler for the manufacture of medical tablets.Исследован процесс получения микрокристаллической целлюлозы из волокон недревесного растительного сырья (льна, конопли, кенафа) с использованием кислотного предгидролиза, щелочно-сульфитно-спиртового способа делигнификации и окислительно-органосольвентной обработки. Установлено, что проведение кислотного предгидролиза на первой стадии получения микрокристаллической целлюлозы позволяет значительно уменьшить содержание минеральных веществ (на 62—75 %), частично выход волокнистого полуфабриката (на 9—12 %) и содержание остаточного лигнина (на 20—30 %) по сравнению с исходным сырьем. Проведение органосольвентной делигнификации уменьшает до 1 % содержание остаточного лигнина в целлюлозе из всех исследованных волокон. Сокращено количество стадий технологического процесса получения микрокристаллической целлюлозы за счет объединения процессов отбеливания и гидролиза органосольвентной целлюлозы из волокон лубяных культур с использованием смеси растворов уксусной кислоты и пероксида водорода концентрацией 35 и 30 % соответственно. Полученная микрокристаллическая целлюлоза из волокон лубяных растений соответствует требованиям стандарта и рекомендуется для использования на фармацевтических предприятиях в качестве наполнителя для изготовления лекарственных таблеток

Получение оксицеллюлозы из хлопковых волокон действием различных окислителей

Проблематика. Розробка технологій виробництва різних за призначенням матеріалів із альтернативних нафті й газу природних джерел сировини, зокрема з целюлози. Мета дослідження. Визначення оптимальних значень технологічних параметрів процесу окиснення бавовняних волокон дією різних окисників – пероксиду водню, Оксону, PINO – на показники якості оксицелюлози. Методика реалізації. Окиснення механічно подрібнених бавовняних волокон розчинами пероксиду водню, Оксону і PINO проводили з барботуванням повітря за допомогою компресора через розчин целюлози в круглодонній колбі, зануреній у водяну баню необхідної температури. Для визначення оптимальних параметрів процесу використовували методи планування експерименту та оптимізації. Результати дослідження. Досліджені окисники для одержання оксицелюлози із бавовняних волокон за збільшенням ефективності розміщуються в такий ряд: пероксид водню – Оксон – PINO. Методом повного факторного експерименту визначено рівняння регресії, які адекватно описують процес отримання оксицелюлози із волокон бавовни дією Оксону і PINO, а за допомогою методу Гаусса–Зейделя – оптимальні значення технологічних параметрів процесу одержання оксицелюлози. Показано, що проведення процесу окиснення бавовняних волокон за оптимальними значеннями технологічних параметрів дає змогу отримати бавовняну оксицелюлозу із вмістом карбоксильних груп до 3 %. Висновки. Одержана оксицелюлоза може використовуватися в медицині як один із компонентів нетоксичних, кровоспинних, антимікробних матеріалів.Background. Development of production technologies of materials for various purposes of alternatives to crude oil and natural gas sources of raw material, in particular cellulose. Objective. To determine the optimal values of technological parameters of cotton fiber oxidation by action of various oxidants — hydrogen peroxide, Oxone, PINO — on quality of oxycellulose. Methods. Oxidation of mechanically chopped cotton fibers by solution of hydrogen peroxide, Oxone and PINO was performed with air bubbling by the compressor through solution of cellulose in round-bottomed flask immersed in a water bath of the required temperature. The methods of experiment planning and optimization were used to determine the optimum process parameters. Results. Studied oxidants for oxycellulose of cotton fibers to increase efficiency are in the following order: hydrogen peroxide — Oxone — PINO. The method of full factorial experiment was used to determine the adequate regression equations that describe the process of oxycellulose obtaining by action of Oxone and PINO, and the Gauss-Seidel method was used to determine the optimal values of technological parameters of oxycellulose obtaining. It is shown that oxidation of cotton fibers for optimal values of technological parameters allows getting oxycellulose with the content of carboxyl groups to 3 %. Conclusions. The obtained oxycellulose can be used in medicine as a component of non-toxic, hemostatic, antimicrobial materials.Проблематика. Разработка технологий производства различных по назначению материалов из альтернативных нефти и газу природных источников сырья, в частности из целлюлозы. Цель исследования. Определение оптимальных значений технологических параметров процесса окисления хлопковых волокон действием различных окислителей – пероксида водорода, Оксона, PINO – на показатели качества оксицелюлозы. Методика реализации. Окисление механически измельченных хлопковых волокон растворами пероксида водорода, Оксона и PINO проводили с барботированием воздуха при помощи компрессора через раствор целлюлозы в круголодонной колбе, погруженной в водяную баню необходимой температуры. Для определения оптимальных параметров процесса использовали методы планирования эксперимента и оптимизации. Результаты исследования. Исследованные окислители для получения оксицеллюлозы из хлопковых волокон по увеличению эффективности располагаются в следующий ряд: пероксид водорода – Оксон – PINO. Методом полного факторного эксперимента определены уравнения регрессии, адекватно описывающие процесс получения оксицеллюлозы из волокон хлопка действием Оксона и PINO, а с помощью метода Гаусса–Зейделя – оптимальные значения технологических параметров процесса получения оксицеллюлозы. Показано, что проведение процесса окисления хлопковых волокон по оптимальным значениям технологических параметров позволяет получить оксицеллюлозу с содержанием карбоксильных групп до 3 %. Выводы. Полученная оксицеллюлоза может использоваться в медицине как один из компонентов нетоксичных, кровоостанавливающих, антимикробных материалов

Functional conservation of the Drosophila hybrid incompatibility gene Lhr

<p>Abstract</p> <p>Background</p> <p>Hybrid incompatibilities such as sterility and lethality are commonly modeled as being caused by interactions between two genes, each of which has diverged separately in one of the hybridizing lineages. The gene <it>Lethal hybrid rescue </it>(<it>Lhr</it>) encodes a rapidly evolving heterochromatin protein that causes lethality of hybrid males in crosses between <it>Drosophila melanogaster </it>females and <it>D. simulans </it>males. Previous genetic analyses showed that hybrid lethality is caused by <it>D. simulans Lhr </it>but not by <it>D. melanogaster Lhr</it>, confirming a critical prediction of asymmetry in the evolution of a hybrid incompatibility gene.</p> <p>Results</p> <p>Here we have examined the functional properties of <it>Lhr </it>orthologs from multiple Drosophila species, including interactions with other heterochromatin proteins, localization to heterochromatin, and ability to complement hybrid rescue in <it>D. melanogaster</it>/<it>D. simulans </it>hybrids. We find that these properties are conserved among most <it>Lhr </it>orthologs, including <it>Lhr </it>from <it>D. melanogaster</it>, <it>D. simulans </it>and the outgroup species <it>D. yakuba</it>.</p> <p>Conclusions</p> <p>We conclude that evolution of the hybrid lethality properties of <it>Lhr </it>between <it>D. melanogaster </it>and <it>D. simulans </it>did not involve extensive loss or gain of functions associated with protein interactions or localization to heterochromatin.</p

Direct Percutaneous Left Ventricular Access and Port Closure Pre-Clinical Feasibility

ObjectivesThis study sought to evaluate feasibility of nonsurgical transthoracic catheter-based left ventricular (LV) access and closure.BackgroundImplanting large devices, such as mitral or aortic valve prostheses, into the heart requires surgical exposure and repair. Reliable percutaneous direct transthoracic LV access and closure would allow new nonsurgical therapeutic procedures.MethodsPercutaneous direct LV access was performed in 19 swine using real-time magnetic resonance imaging (MRI) and an “active” MRI needle antenna to deliver an 18-F introducer sheath. The LV access ports were closed percutaneously using a commercial ventricular septal defect occluder and an “active” MRI delivery cable for enhanced visibility. We used “permissive pericardial tamponade” (temporary fluid instillation to separate the 2 pericardial layers) to avoid pericardial entrapment by the epicardial disk. Techniques were developed in 8 animals, and 11 more were followed up to 3 months by MRI and histopathology.ResultsImaging guidance allowed 18-F sheath access and closure with appropriate positioning of the occluder inside the transmyocardial tunnel. Of the survival cohort, immediate hemostasis was achieved in 8 of 11 patients. Failure modes included pericardial entrapment by the epicardial occluder disk (n = 2) and a true-apex entry site that prevented hemostatic apposition of the endocardial disk (n = 1). Reactive pericardial effusion (192 ± 118 ml) accumulated 5 ± 1 days after the procedure, requiring 1-time drainage. At 3 months, LV function was preserved, and the device was endothelialized.ConclusionsDirect percutaneous LV access and closure is feasible using real-time MRI. A commercial occluder achieved hemostasis without evident deleterious effects on the LV. Having established the concept, further clinical development of this approach appears realistic

Influence of hypoxia on the domiciliation of Mesenchymal Stem Cells after infusion into rats: possibilities of targeting pulmonary artery remodeling via cells therapies?

BACKGROUND: Bone marrow (BM) cells are promising tools for vascular therapies. Here, we focused on the possibility of targeting the hypoxia-induced pulmonary artery hypertension remodeling with systemic delivery of BM-derived mesenchymal stem cells (MSCs) into non-irradiated rats. METHODS: Six-week-old Wistar rats were exposed to 3-week chronic hypoxia leading to pulmonary artery wall remodeling. Domiciliation of adhesive BM-derived CD45(- )CD73(+ )CD90(+ )MSCs was first studied after a single intravenous infusion of Indium-111-labeled MSCs followed by whole body scintigraphies and autoradiographies of different harvested organs. In a second set of experiments, enhanced-GFP labeling allowed to observe distribution at later times using sequential infusions during the 3-week hypoxia exposure. RESULTS: A 30% pulmonary retention was observed by scintigraphies and no differences were observed in the global repartition between hypoxic and control groups. Intrapulmonary radioactivity repartition was homogenous in both groups, as shown by autoradiographies. BM-derived GFP-labeled MSCs were observed with a global repartition in liver, in spleen, in lung parenchyma and rarely in the adventitial layer of remodeled vessels. Furthermore this global repartition was not modified by hypoxia. Interestingly, these cells displayed in vivo bone marrow homing, proving a preservation of their viability and function. Bone marrow homing of GFP-labeled MSCs was increased in the hypoxic group. CONCLUSION: Adhesive BM-derived CD45(- )CD73(+ )CD90(+ )MSCs are not integrated in the pulmonary arteries remodeled media after repeated intravenous infusions in contrast to previously described in systemic vascular remodeling or with endothelial progenitor cells infusions

TNF-alpha Is Required for the Attraction of Mesenchymal Precursors to White Adipose Tissue in Ob/ob Mice

Most adult tissues harbour a stem cell subpopulation (Mesenchymal Precursors or MPs) that represent a small proportion of the total cell number and have the potential to differentiate into several cell types within the mesenchymal lineage. In adipose tissue, adipocytes account for two-thirds of the total cell number. The remaining cells include blood and endothelial cells, along with adipocyte precursors (adipose MPs). Obesity is defined as an excess of body fat that frequently results in a significant impairment of health. The ob/ob mice bear a mutation in the ob gene that causes a deficiency in the hormone leptin and hence obesity. Here, we present evidence that ob/ob mice have a dramatic decrease in the resident MP pool of several tissues, including squeletal muscle, heart, lung and adipose tissue. Moreover, we show that that there is a migration of MP cells from distant organs, as well as homing of these cells to the adipose tissue mass of the ob/ob mice. We call this process adipotaxis. Once in the adipose tissue, migrant MPs undergoe adipose differentiation, giving rise to new differentiated adipocytes within the adipose mass. Finally, we provide evidence that adipotaxis is largely explained by the production of high levels of Tumor Necrosis Factor-alpha (TNF-α) within the ob/ob adipose tissue. The therapeutic implications for human obesity as well as for regenerative medicine are further discussed in this paper

Short-Term Exposure of Multipotent Stromal Cells to Low Oxygen Increases Their Expression of CX3CR1 and CXCR4 and Their Engraftment In Vivo

The ability of stem/progenitor cells to migrate and engraft into host tissues is key to their potential use in gene and cell therapy. Among the cells of interest are the adherent cells from bone marrow, referred to as mesenchymal stem cells or multipotent stromal cells (MSC). Since the bone marrow environment is hypoxic, with oxygen tensions ranging from 1% to 7%, we decided to test whether hypoxia can upregulate chemokine receptors and enhance the ability of human MSCs to engraft in vivo. Short-term exposure of MSCs to 1% oxygen increased expression of the chemokine receptors CX3CR1and CXCR4, both as mRNA and as protein. After 1-day exposure to low oxygen, MSCs increased in vitro migration in response to the fractalkine and SDF-1α in a dose dependent manner. Blocking antibodies for the chemokine receptors significantly decreased the migration. Xenotypic grafting into early chick embryos demonstrated cells from hypoxic cultures engrafted more efficiently than cells from normoxic cultures and generated a variety of cell types in host tissues. The results suggest that short-term culture of MSCs under hypoxic conditions may provide a general method of enhancing their engraftment in vivo into a variety of tissues

MRI roadmap-guided transendocardial delivery of exon-skipping recombinant adeno-associated virus restores dystrophin expression in a canine model of Duchenne muscular dystrophy

Duchenne muscular dystrophy (DMD) cardiomyopathy patients currently have no therapeutic options. We evaluated catheter-based transendocardial delivery of a recombinant adeno-associated virus (rAAV) expressing a small nuclear U7 RNA (U7smOPT) complementary to specific cis-acting splicing signals. Eliminating specific exons restores the open-reading frame resulting in translation of truncated dystrophin protein. To test this approach in a clinically relevant DMD model, golden retriever muscular dystrophy (GRMD) dogs received serotype 6 rAAV-U7smOPT via the intracoronary or transendocardial route. Transendocardial injections were performed with an injection-tipped catheter and fluoroscopic guidance using X-ray fused with MRI (XFM) roadmaps. Three months after treatment, tissues were analyzed for DNA, RNA, dystrophin protein, and histology. Whereas intracoronary delivery did not result in effective transduction, transendocardial injections, XFM guidance, enabled 30±10 non-overlapping injections per animal. Vector DNA was detectable in all samples tested and ranged from 3000 vector genome copies per cell. RNA analysis, western blot analysis, and immunohistology demonstrated extensive expression of skipped RNA and dystrophin protein in the treated myocardium. Left ventricular function remained unchanged over a three-month follow-up. These results demonstrated that effective transendocardial delivery of rAAV-U7smOPT was achieved using XFM. This approach restores an open reading frame for dystrophin in affected dogs and has potential clinical utility