Искусственный нервный проводник для направленного роста периферических нервов (кадаверное исследование)

At present, the search for effective ways of restoring peripheral nerves with anatomical damage continues. Autoplasty still remains the gold standard, which, however, is not without its drawbacks. The use of nerve implants for promoting directional axon growth is essential and promising.Objective: to study the biomechanical properties of laboratory samples of an artificial nerve conduit (NGC) made of hybrid biomaterials and to, on cadaveric material, assess the technical feasibility of using them in surgical practice to repair extended peripheral nerve defects.Material and methods. The objects of the study were three electrospun NGC samples: from synthetic material (polycaprolactone, PCL) and hybrid biomaterials (PCL + gelatin or PCL + collagen). The work compared the physical and mechanical properties of NGC: stiffness, plasticity, elasticity, brittleness, resistance to chemical attack, their ability to be impregnated with liquid media, permeability, possibility of making an anastomosis between the implant and the nerve during surgical procedure. Cadaveric material was the object of the study: we used a dissected superficial sensory branch of the human right radial nerve, 2 mm in diameter, isolated on the forearm, about 12 cm in length, because it most corresponded to the diameter of the NGC samples tested. After surgery, the echogenic features of the implants and their anastomoses with the nerve were assessed by ultrasound imaging.Results. It was found that hybrid NGC samples, based on their biomechanical properties, are fundamentally suitable for use in surgical practice, to ensure growth and replacement of a peripheral nerve defect. However, the best composition of a nerve guide can be established after comparative preclinical study of the biocompatible and functional properties of hybrid material samples.Conclusion. The physical and mechanical properties of the investigated NGC samples made of hybrid biomaterials meet the technical requirements for implantable nerve conduits for surgical application.В настоящее время продолжаются поиски эффективных способов восстановления периферических нервов при анатомическом нарушении их целостности. Золотым стандартом по-прежнему остается аутопластика, которая, однако, не лишена недостатков. Актуальным и перспективным является метод применения нервных имплантатов для направленного роста аксонов.Цель: изучить биомеханические свойства лабораторных образцов искусственного нервного проводника (ИНП) – нервного кондуита, изготовленных из гибридных биоматериалов, и на кадаверном материале оценить техническую возможность их применения в хирургической практике для восстановления протяженных дефектов периферических нервов.Материал и методы. Объектами исследования служили изготовленные методом электроспиннинга три образца ИНП: из синтетического материала – поликапролактона (ПКЛ) и гибридных биоматериалов (ПКЛ с желатином или коллагеном). В ходе работы сравнивались физические и механические свойства ИНП: жесткость, пластичность, эластичность, хрупкость, устойчивость образцов к химическому воздействию, их способность к пропитыванию жидкими средами, проницаемость, возможность наложения анастомоза между имплантатом и нервом во время хирургической операции. В качестве кадаверного материала использовали поверхностную чувствительную ветвь правого лучевого нерва человека диаметром 2 мм, выделенную на предплечье протяженностью около 12 см, как наиболее соответствующую диаметру тестируемых образцов ИНП. После хирургической операции оценивали эхогенные признаки имплантатов и их анастомозов с нервом методом ультразвуковой визуализации.Результаты. Установлено, что образцы ИНП из гибридных материалов по биомеханическим свойствам принципиально пригодны для использования в хирургической практике для обеспечения роста и замещения дефекта периферических нервов. Однако наилучший состав нервного проводника может быть установлен после проведения сравнительных доклинических исследований биосовместимых и функциональных свойств образцов из гибридных материалов.Заключение. Физические и механические свойства исследуемых образцов ИНП из гибридных биоматериалов соответствуют техническим требованиям, предъявляемым к имплантируемым нервным проводникам при их хирургическом применении

Evaporation kinetics in swollen porous polymeric networks

Ponencia presentada en el Congreso Euromar 2014.Fil: Velasco, Manuel Isaac. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Física Enrique Gaviola; Argentina.Fil: Silletta, Emilia Victoria. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Física Enrique Gaviola; Argentina.Fil: Monti, Gustavo Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Física Enrique Gaviola; Argentina.Fil: Acosta, Rodolfo Héctor. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Física Enrique Gaviola; Argentina.Fil: Velasco, Manuel Isaac. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; Argentina.Fil: Silletta, Emilia Victoria. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; Argentina.Fil: Monti, Gustavo Alberto. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; Argentina.Fil: Acosta, Rodolfo Héctor. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; Argentina.Fil: Gomez, Cesar Gerardo. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Departamento de Química Orgánica; Argentina.Fil: Strumia, Miriam Cristina. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Departamento de Química Orgánica; Argentina.Fil: Gomez, Cesar Gerardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto Multidisciplinario de Biología Vegetal; Argentina.Fil: Gomez, Cesar Gerardo. Universidad Nacional de Córdoba. Instituto Multidisciplinario de Biología Vegetal; Argentina.Fil: Strumia, Miriam Cristina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto Multidisciplinario de Biología Vegetal; Argentina.Fil: Strumia, Miriam Cristina. Universidad Nacional de Córdoba. Instituto Multidisciplinario de Biología Vegetal; Argentina.Polymer matrices with well defined structure and pore sizes are widely used in several areas of chemistry such as catalysis, enzyme immobilization, HPLC, adsorbents or controlled drug release. These polymers have pores in its structure both in the dry and swollen state. Although it is well known that the structures and properties greatly differ between these two states, only few methods provide information about the swollen one, even though most of the applications involve the matrices in this situation. Nuclear Magnetic Resonance (NMR) is a suitable tool for the study of the molecular dynamics of different liquids spatially confined in macro, meso and nanopores, through changes in the relaxation times. In transverse relaxation experiments, either diffusion inside the pore, or relaxation induced by mobility restriction of the liquid near the wall, are additional sources of relaxation, which are extremely useful in the determination of structural and functional properties.Fil: Velasco, Manuel Isaac. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Física Enrique Gaviola; Argentina.Fil: Silletta, Emilia Victoria. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Física Enrique Gaviola; Argentina.Fil: Monti, Gustavo Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Física Enrique Gaviola; Argentina.Fil: Acosta, Rodolfo Héctor. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Física Enrique Gaviola; Argentina.Fil: Velasco, Manuel Isaac. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; Argentina.Fil: Silletta, Emilia Victoria. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; Argentina.Fil: Monti, Gustavo Alberto. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; Argentina.Fil: Acosta, Rodolfo Héctor. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; Argentina.Fil: Gomez, Cesar Gerardo. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Departamento de Química Orgánica; Argentina.Fil: Strumia, Miriam Cristina. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Departamento de Química Orgánica; Argentina.Fil: Gomez, Cesar Gerardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto Multidisciplinario de Biología Vegetal; Argentina.Fil: Gomez, Cesar Gerardo. Universidad Nacional de Córdoba. Instituto Multidisciplinario de Biología Vegetal; Argentina.Fil: Strumia, Miriam Cristina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto Multidisciplinario de Biología Vegetal; Argentina.Fil: Strumia, Miriam Cristina. Universidad Nacional de Córdoba. Instituto Multidisciplinario de Biología Vegetal; Argentina.Física de los Materiales Condensado

Comparative analysis of serum and tumor vascular endothelial growth factor, insulin-like growth factor 1, matrix metalloproteinase 7 levels in patients with ovarian cancer

Aim: To perform a comparative analysis with simultaneous measurement of vascular endothelial growth factor (VEGF), insulin-like growth factor 1 (IGF1) and matrix metalloproteinase 7 (MMP7) in serum samples taken from healthy women and ovarian cancer patients; to perform association of these markers with their expression in primary tumors depending on clinical, morphological and biochemical characteristics of the disease and its prognosis. Materials and methods: We assessed 54 treatment-naïve patients with ovarian cancer aged from 23 to 74 years (mean ± SD, 53.2 ± 1.9), being at various FIGO stages of the disease. The control group consisted of 120 healthy women of matched age and reproductive status, in whom serum biomarker levels were studied. Patient survival was assessed by the Kaplan-Meier method, with survival curves compared with log-rank test. All analyses were done with “STATISTICA” and SPSS software. Results: Serum VEGF levels in ovarian cancer patients were significantly (p < 0.0001) higher compared those in the control. The most informative cut-off values differentiating the groups studied were serum VEGF values of < 350 pg/ml (median value in the control) and > 505 pg/ml (upper quartile in the control). With 505 pg/ml taken as a threshold, the test had sensitivity of 79.6% and specificity of 75%. Another cut-off value of serum VEGF level between the patients with ovarian cancer and the control group (510 pg/ml) was derived from ROC curves and 75% sensitivity and 78.2% specificity. No acceptable cut-off value for serum IGF1 to differentiate between the patients with ovarian cancer and the controls could be obtained from the ROC curves. Serum MMP7 levels in the patients with ovarian cancer were significantly higher than those in the control group (Mann-Whitney test p < 0.0001). With ROC curves, the best sensitivity to specificity ratio for MMP7 value of 4.6 ng/ml was obtained to differentiate between the patients with ovarian cancer and the controls (sensitivity 83.3%, and specificity 81%). The variance analysis did not reveal any association between serum VEGF, IGF1 and MMP7 and age of patients with ovarian cancer, tumor histology, concomitant somatic and gynecological diseases, and CA-125 levels. Serum VEGF and IGF1 levels did not correlate with the stage of ovarian cancer, in contrast to MMP7, whose levels were significantly higher in stages IIIc–IV. The median VEGF level significantly increased as the degree of differentiation decreased from 510 to 622 pg/ml (p < 0.002), while median IGF1, on the contrary, decreased from 219 to 116 pg/ml (p < 0.0001). There was a direct correlation between serum and tumor VEGF levels in ovarian cancer patients (r = 0.65, p < 0.0001). On the contrary, there was an inverse correlation between serum and tumor IGF1 levels (r = -0.68, p < 0.0001). Serum and tumor MMP7 levels remained unrelated to each other. Tumor VEGF, IGF1 and MMP7 content was unrelated to the age of the patients, their reproductive status, presence of concomitant somatic and gynecological diseases, histology of ovarian cancer, and serum CA-125 levels. VEGF levels in the tumor were not associated with the stage of ovarian cancer, but in patients with initial stages Ia and Ib stages MMP7 values significantly lower (2.1 ng/mg protein) compared to those in stages IIIc and IV (6.1 and 4.7 ng/mg protein, respectively, p < 0.05). Similar pattern was noted for IGF1: tumor IGF1 values in the patients with stages Ia–Ib were significantly lower (0.5 ng/mg protein) than those with stages IIIc–IV (median, 1.3–1.4 ng/mg protein). A significant increase in both serum and tumor VEGF levels was detected in the patients with ovarian cancer with decreased degree of differentiation. On the contrary, tumor IGF1 levels, but not serum ones, were significantly increased from 0.6 to 1.4 ng/ml in the patients with poorly differentiated ovarian cancer. MMP7 tumor expression did not depend on the degree of its differentiation. Serum VEGF levels above 700 pg/ml and tumor levels of above 590 ng/mg protein should be considered as unfavorable prognostic factors in patients with ovarian cancer

Cryogels for Biotechnological Applications

Cryogels are formed in a semifrozen state when the solvent is frozen, but solutes are still soluble. The ice crystals are porogens and, upon thawing the system, pores appear where the frozen solvent was found earlier. Such gels have large pores, are elastic, and offer interesting opportunities in biotechnology. Cryogels with their large pores can meet demands that traditional chromatographic media cannot. This also opens up opportunities for the separation of cells because upon passage through the gel cells may interact with specific groups on the pore walls, thereby becoming retarded and/or captured. A range of applications have been studied: isolation of microbial cells, capturing of cancer cells, and use of cryogels as matrices for immobilized cell reactors. Furthermore, the robustness of the gels allows new applications, for example in environmental separation