Synthesis of alginate-silica hybrid hydrogel for biocatalytic conversion by ß-glucosidase in microreactor

The organic–inorganic hybrid materials have been used in different fields to immobilize biomolecules since they offer many advantages. The aim of this study was to optimize and characterize the alginate-silica hybrid hydrogel as a stable and injectable form for microfluidic systems using internal gelation method and increase the stability and activity of immobilized enzyme for biocatalytic conversions as well. Characterization was carried out by scanning electron microscopy, energy dispersive spectroscopy/mapping, Brunauer–Emmett–Teller, Barrett–Joyner–Halenda, and Fourier-transform infrared spectroscopy analyses, and the shrinkages of monoliths were evaluated. Subsequent to optimizing the enzyme concentration (40 µg), hydrolytic conversion of 4-nitrophenyl ß-d-glucopyranoside (pNPG) was performed to understand the behavior of the bioconversion in the microfluidic system. The yield was 94% which reached the equilibrium at 24 h indicating that the alginate-silica gel derived microsystem overcome some drawbacks of monolithic systems. Additionally, bioconversion of Ruscus aculeatus saponins was carried out at the same setup in order to obtain aglycon part, which has pharmaceutical significance. Although pure aglycon could not be achieved, an intermediate compound was obtained based on the HPLC analysis. The developed formulation can be utilized for various life science applications. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim113M050 15-FBE-012This work was supported by the Scientific and Technological Research Council of Turkey, TUBITAK (113M050), and Ege University Research Fund (15-FBE-012). The grant from TUBITAK 2210-C National Graduate Scholarship Program is highly appreciated. Additionally, the authors thank Dr. Ozgur Tag for his support in HPLC analysis. -

Tortuous vertebral artery triggering vertebral foramen expansion and radiculopathy in a 19-year-old patient: A case report

Background: Arterial tortuosity is a widespread condition commonly occurring in cerebral arteries and often associated with the elderly. Moderate arterial tortuosity is often not symptomatic, but if there is severe tortuosity, various symptoms may occur, depending on the localization. In the literature, many factors have been reported as causing tortuosity in the vertebral arteries. In this case report, considering the age of our patient, we propose that, in addition to these previously reported reasons, congenital factors may also contribute to this situation. Case presentation: We present a case of a 19-year-old Turkish patient with a tortuous vertebral artery causing pain and tingling in the right shoulder and neck. Magnetic resonance imaging revealed vertebral foramen enlargement thought to be secondary to a loop formation in the vertebral artery. The diagnosis was confirmed by magnetic resonance angiography. Conclusions: There are many causes of cervical radiculopathy. Arterial tortuosity, a rare cause of radiculopathy, should be considered as a differential diagnosis. Consideration of the existence of this variation is of great importance in preventing possible dangerous complications during surgery. © 2020 The Author(s).2-s2.0-85091737646PubMed: 3298152