316 research outputs found

    P164 Effects of reduced oxygen tension and long-term mechanical stimulation on chondrocytes-polymer constructs

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    Pengaruh Motivasi Kerja Terhadap Kinerja Karyawan Wilayah Telkom Jabar Barat Utara (Witel Bekasi)

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    Sumber daya manusia (SDM) penting bagi Perusahaan karena memiliki peran sebagai potensi penggerak seluruh aktivitas Perusahaan. Perusahaan yang memiliki SDM yang berkualitas dapat dengan mudah mengintegrasikan visi Perusahaan dengan tujuan Perusahaan kepada karyawannya sehingga pencapaian tujuan Perusahaan bisa tercapai. Penelitian ini dilakukan di Wilayah Telkom Jabar Barat Utara (Witel Bekasi) dengan menggunakan motivasi kerja sebagai variabel independen dan kinerja sebagai variabel dependen. Tujuan penelitian ini untuk mengetahui bagaimana pengaruh motivasi kerja yang terdiri dari kebutuhan prestasi, kebutuhan afiliasi dan kebutuhan kekuasaan terhadap kinerja karyawan Witel Bekasi. Penelitian ini merupakan penelitian deskriptif dan kausal. Analisis data yang digunakan adalah analisis deskriptif, analisis regresi linier berganda, uji hipotesis secara simultan (uji F), uji hipotesis secara parsial (uji t), dan koefisien determinasi. Teknik sampel yang digunakan adalah Proportionate Stratified Random Sampling. Berdasarkan hasil kuesioner dengan 180 orang responden, penilaian karyawan terhadap motivasi kerja dan kinerja termasuk dalam kategori sangat tinggi. Pada hasil pengujian hipotesis dapat disimpulkan bahwa variabel Motivasi Kerja (X) yang terdiri dari Kebutuhan Prestasi (X1), Kebutuhan Afiliasi (X2) dan Kebutuhan Kekuasaan (X3) secara simultan dan parsial berpengaruh signifikan terhadap Kinerja Karyawan (Y). Pada hasil uji koefisien determinasi (R2) diperoleh nilai sebesar 0.551. Hal ini berarti bahwa besarnya pengaruh motivasi kerja terhadap kinerja karyawan adalah sebesar 55.1%, sedangkan sisanya 44.9% dipengaruhi faktor-faktor lain yang tidak diteliti dalam penelitian ini

    Bioreactor mechanically guided 3D mesenchymal stem cell chondrogenesis using a biocompatible novel thermo-reversible methylcellulose-based hydrogel

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    Autologous chondrocyte implantation for cartilage repair represents a challenge because strongly limited by chondrocytes' poor expansion capacity in vitro. Mesenchymal stem cells (MSCs) can differentiate into chondrocytes, while mechanical loading has been proposed as alternative strategy to induce chondrogenesis excluding the use of exogenous factors. Moreover, MSC supporting material selection is fundamental to allow for an active interaction with cells. Here, we tested a novel thermo-reversible hydrogel composed of 8% w/v methylcellulose (MC) in a 0.05 M Na 2 SO 4 solution. MC hydrogel was obtained by dispersion technique and its thermo-reversibility, mechanical properties, degradation and swelling were investigated, demonstrating a solution-gelation transition between 34 and 37 °C and a low bulk degradation (<20%) after 1 month. The lack of any hydrogel-derived immunoreaction was demonstrated in vivo by mice subcutaneous implantation. To induce in vitro chondrogenesis, MSCs were seeded into MC solution retained within a porous polyurethane (PU) matrix. PU-MC composites were subjected to a combination of compression and shear forces for 21 days in a custom made bioreactor. Mechanical stimulation led to a significant increase in chondrogenic gene expression, while histological analysis detected sulphated glycosaminoglycans and collagen II only in loaded specimens, confirming MC hydrogel suitability to support load induced MSCs chondrogenesis

    Bioreactor mechanically guided 3D mesenchymal stem cell chondrogenesis using a biocompatible novel thermo-reversible methylcellulose-based hydrogel

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    Autologous chondrocyte implantation for cartilage repair represents a challenge because strongly limited by chondrocytes' poor expansion capacity in vitro. Mesenchymal stem cells (MSCs) can differentiate into chondrocytes, while mechanical loading has been proposed as alternative strategy to induce chondrogenesis excluding the use of exogenous factors. Moreover, MSC supporting material selection is fundamental to allow for an active interaction with cells. Here, we tested a novel thermo-reversible hydrogel composed of 8% w/v methylcellulose (MC) in a 0.05 M Na 2 SO 4 solution. MC hydrogel was obtained by dispersion technique and its thermo-reversibility, mechanical properties, degradation and swelling were investigated, demonstrating a solution-gelation transition between 34 and 37 °C and a low bulk degradation (<20%) after 1 month. The lack of any hydrogel-derived immunoreaction was demonstrated in vivo by mice subcutaneous implantation. To induce in vitro chondrogenesis, MSCs were seeded into MC solution retained within a porous polyurethane (PU) matrix. PU-MC composites were subjected to a combination of compression and shear forces for 21 days in a custom made bioreactor. Mechanical stimulation led to a significant increase in chondrogenic gene expression, while histological analysis detected sulphated glycosaminoglycans and collagen II only in loaded specimens, confirming MC hydrogel suitability to support load induced MSCs chondrogenesis

    Cell-seeded thermoreversible hydrogel-polyurethane composites for nucleus pulposus augmentation

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    Tissue engineering represents an alternative approach to the current invasive surgical procedures for the intervertebral disc (IVD) repair. The combination of injectable hydrogels and elastic biomaterials allow three-dimensional cell cultures and provide mechanical stability. In the present study a thermoreversible hyaluronan (HA) hydrogel as well as fibrin glue were mixed with polyurethane (PU) and their effect was investigated on the proliferation and differentiation of human IVD (hIVD cells) and mesenchymal stem cells (hMSCs) by in vitro and ex-vivo experiments

    Mechanical stress inhibits early stages of endogenous cell migration: A pilot study in an ex vivo osteocho

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    Cell migration has a central role in osteochondral defect repair initiation and biomaterial-mediated regeneration. New advancements to reestablish tissue function include biomaterials and factors promoting cell recruitment, differentiation and tissue integration, but little is known about responses to mechanical stimuli. In the present pilot study, we tested the influence of extrinsic forces in combination with biomaterials releasing chemoattractant signals on cell migration. We used an ex vivo mechanically stimulated osteochondral defect explant filled with fibrin/hyaluronan hydrogel, in presence or absence of platelet-derived growth factor-BB or stromal cell-derived factor 1, to assess endogenous cell recruitment into the wound site. Periodic mechanical stress at early time point negatively influenced cell infiltration compared to unloaded samples, and the implementation of chemokines to increase cell migration was not efficient to overcome this negative effect. The gene expression at 15 days of culture indicated a marked downregulation of matrix metalloproteinase (MMP)13 and MMP3, a decrease of β1 integrin and increased mRNA levels of actin in osteochondral samples exposed to complex load. This work using an ex vivo osteochondral mechanically stimulated advanced platform demonstrated that recurrent mechanical stress at early time points impeded cell migration into the hydrogel, providing a unique opportunity to improve our understanding on management of joint injury

    Biochemical characterisation of lipase from a new strain of Bacillus sp. ITP-001

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    Lipases are characterised mainly by catalytic versatility and application in different industrial segments. The aim of this study was to biochemically characterise a lipase from a new strain of Bacillus sp. ITP-001. The isoelectric point and molecular mass were 3.12 and 54 kDa, respectively. The optima lipase activity was 276 U g-1 at pH 7.0 and a temperature of 80 ºC, showing greater stability at pH 5.0 and 37 ºC. Enzymatic activity was stimulated by various ions and pyridine, and inhibited by Cu+ and ethanol. The values of Km and v max were 105.26 mmol and 0.116 mmol min-1 g-1, respectively determined by the Eadie-Scatchard method

    Enhanced chondrogenic phenotype of primary bovine articular chondrocytes in Fibrin-Hyaluronan hydrogel by multi-axial mechanical loading and FGF18

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    Current treatments for cartilage lesions are often associated with fibrocartilage formation and donor site morbidity. Mechanical and biochemical stimuli play an important role in hyaline cartilage formation. Biocompatible scaffolds capable of transducing mechanical loads and delivering bioactive instructive factors may better support cartilage regeneration. In this study we aimed to test the interplay between mechanical and FGF-18 mediated biochemical signals on the proliferation and differentiation of primary bovine articular chondrocytes embedded in a chondro-conductive Fibrin-Hyaluronan (FB/HA) based hydrogel. Chondrocytes seeded in a Fibrin-HA hydrogel, with or without a chondro-inductive, FGFR3 selective FGF18 variant (FGF-18v) were loaded into a joint-mimicking bioreactor applying controlled, multi-axial movements, simulating the natural movements of articular joints. Samples were evaluated for DNA content, sulphated glycosaminoglycan (sGAG) accumulation, key chondrogenic gene expression markers and histology. Under moderate loading, samples produced particularly significant amounts of sGAG/DNA compared to unloaded controls. Interestingly there was no significant effect of FGF-18v on cartilage gene expression at rest. Following moderate multi-axial loading, FGF-18v upregulated the expression of Aggrecan (ACAN), Cartilage Oligomeric Matrix Protein (COMP), type II collagen (COL2) and Lubricin (PRG4). Moreover, the combination of load and FGF-18v, significantly downregulated Matrix Metalloproteinase-9 (MMP-9) and Matrix Metaloproteinase-13 (MMP-13), two of the most important factors contributing to joint destruction in OA. Biomimetic mechanical signals and FGF-18 may work in concert to support hyaline cartilage regeneration and repair. Statement of significance: Articular cartilage has very limited repair potential and focal cartilage lesions constitute a challenge for current standard clinical procedures. The aim of the present research was to explore novel procedures and constructs, based on biomaterials and biomechanical algorithms that can better mimic joints mechanical and biochemical stimulation to promote regeneration of damaged cartilage. Using a hydrogel-based platform for chondrocyte 3D culture revealed a synergy between mechanical forces and growth factors. Exploring the mechanisms underlying this mechano-biochemical interplay may enhance our understanding of cartilage remodeling and the development of new strategies for cartilage repair and regeneration

    Validation of UV spectrophotometric method for telithromycin in pharmaceutical formulations and comparison with HPLC and microbiological assay

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    An ultraviolet (UV) spectrophotometric method was developed for the analysis of telithromycin, member of the ketolides, in drug substance and coated tablets. The method validation yielded good results, such as the range, linearity, intra and inter-day precision, accuracy, recovery specificity, and robustness. UV spectrophotometric determinations were performed at 258 nm. Good linearity was obtained between 10.0 and 70.0/ μg mL. A prospective validation showed that the method is linear (r = 1) with precise relative standard deviation (RSD) of 0.4 %. The intra and inter-day precision values were < 2 % for all samples analyzed. The comparison between UV spectrophotometric, high performance liquid chromatography (HPLC) and microbiological assay showed no significant difference between the methodologies. The proposed method is appropriate for the determination of telithromycin in tablets and can be used in routine quality controlColegio de Farmacéuticos de la Provincia de Buenos Aire

    Challenges and strategies in the repair of ruptured annulus fibrosus

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    Lumbar discectomy is the surgical procedure most frequently performed for patients suffering from low back pain and sciatica. Disc herniation as a consequence of degenerative or traumatic processes is commonly encountered as the underlying cause for the painful condition. While discectomy provides favourable outcome in a majority of cases, there are conditions where unmet requirements exist in terms of treatment, such as large disc protrusions with minimal disc degeneration; in these cases, the high rate of recurrent disc herniation after discectomy is a prevalent problem. An effective biological annular repair could improve the surgical outcome in patients with contained disc herniations but otherwise minor degenerative changes. An attractive approach is a tissue-engineered implant that will enable/stimulate the repair of the ruptured annulus. The strategy is to develop three-dimensional scaffolds and activate them by seeding cells or by incorporating molecular signals that enable new matrix synthesis at the defect site, while the biomaterial provides immediate closure of the defect and maintains the mechanical properties of the disc. This review is structured into (1) introduction, (2) clinical problems, current treatment options and needs, (3) biomechanical demands, (4) cellular and extracellular components, (5) biomaterials for delivery, scaffolding and support, (6) pre-clinical models for evaluation of newly developed cell- and material-based therapies, and (7) conclusions. This article highlights that an interdisciplinary approach is necessary for successful development of new clinical methods for annulus fibrosus repair. This will benefit from a close collaboration between research groups with expertise in all areas addressed in this review
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