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1.
J Appl Clin Med Phys ; 22(11): 126-142, 2021 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-34623023

RESUMEN

Radiography remains the most widely used imaging modality throughout the world. Additionally, while it has been demonstrated that a quality control (QC) program, especially in mammography, improves image quality, weekly technologist QC testing might be lacking even where there is clinical qualified medical physicist (CQMP) support. Therefore, the International Atomic Energy Agency (IAEA) developed simple QC phantoms that can easily be used on a regular basis (daily/weekly) for radiography and mammography. These are simple in design and use materials that are easily accessible in most parts of the world. A software application is also developed that automatically analyzes images and Digital Imaging and Communications in Medicine (DICOM) header information. It exports data to a comma-separated values (CSV) file that is read by a Microsoft Excel® spreadsheet for documentation and graphical analysis. The phantom and the software were tested in four institutions (in Costa Rica and the United States of America) both on computed radiography and direct digital mammography and radiography systems. Data were collected over a 3-year period. No corrective actions were taken on the data, but service was performed on two of the units. Results demonstrated noise that could be attributed to suboptimal placement of the phantom and incorrect data being put into the DICOM header. Preliminary evaluation of the IAEA methodology has demonstrated that it can provide meaningful QC data that are sensitive to changes in the imaging systems. Care must be taken at implementation to properly train personnel and ensure that the image data, including the DICOM header, are being correctly transmitted. The methodology gives the opportunity for a single CQMP to provide QC services even to remote sites where travel is prohibitive, and it is feasible and easy to implement.


Asunto(s)
Mamografía , Energía Nuclear , Humanos , Agencias Internacionales , Fantasmas de Imagen , Control de Calidad
2.
Neural Regen Res ; 10(8): 1312-6, 2015 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-26487861

RESUMEN

Alginate scaffold has been considered as an appropriate biomaterial for promoting the differentiation of embryonic stem cells toward neuronal cell lineage. We hypothesized that alginate scaffold is suitable for culturing Wharton's jelly mesenchymal stem cells (WJMSCs) and can promote the differentiation of WJMSCs into neuron-like cells. In this study, we cultured WJMSCs in a three-dimensional scaffold fabricated by 0.25% alginate and 50 mM CaCl2 in the presence of neurogenic medium containing 10 µM retinoic acid and 20 ng/mL basic fibroblast growth factor. These cells were also cultured in conventional two-dimensional culture condition in the presence of neurogenic medium as controls. After 10 days, immunofluorescence staining was performed for detecting ß-tubulin (marker for WJMSCs-differentiated neuron) and CD271 (motor neuron marker). ß-Tubulin and CD271 expression levels were significantly greater in the WJMSCs cultured in the three-dimensional alginate scaffold than in the conventional two-dimensional culture condition. These findings suggest that three-dimensional alginate scaffold cell culture system can induce neuronal differentiation of WJMSCs effectively.

3.
Neural Regen Res ; 10(6): 904-8, 2015 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-26199606

RESUMEN

Cell therapy using stem cell transplantation against cerebral ischemia has been reported. However, it remains controversial regarding the optimal time for cell transplantation and the transplantation route. Rat models of cerebral ischemia were established by occlusion of the middle cerebral artery. At 1, 12 hours, 1, 3, 5 and 7 days after cerebral ischemia, bone marrow mesenchymal stem cells were injected via the tail vein. At 28 days after cerebral ischemia, rat neurological function was evaluated using a 6-point grading scale and the pathological change of ischemic cerebral tissue was observed by hematoxylin-eosin staining. Under the fluorescence microscope, the migration of bone marrow mesenchymal stem cells was examined by PKH labeling. Caspase-3 activity was measured using spectrophotometry. The optimal neurological function recovery, lowest degree of ischemic cerebral damage, greatest number of bone marrow mesenchymal stem cells migrating to peri-ischemic area, and lowest caspase-3 activity in the ischemic cerebral tissue were observed in rats that underwent bone marrow mesenchymal stem cell transplantation at 12 hours after cerebral ischemia. These findings suggest that 12 hours after cerebral ischemia is the optimal time for tail vein injection of bone marrow mesenchymal stem cell transplantation against cerebral ischemia, and the strongest neuroprotective effect of this cell therapy appears at this time.

4.
Int J Stem Cells ; 8(1): 99-105, 2015 May.
Artículo en Inglés | MEDLINE | ID: mdl-26019759

RESUMEN

OBJECTIVES: Brain stroke is the second most important events that lead to disability and morbidity these days. Although, stroke is important, there is no treatment for curing this problem. Nowadays, cell therapy has opened a new window for treating central nervous system disease. In some previous studies the Mesenchymal stem cells and neural stem cells. In this study, we have designed an experiment to assess the combination cell therapy (Mesenchymal and Neural stem cells) effects on brain stroke. METHOD AND MATERIALS: The Mesenchymal stem cells were isolated from adult rat bone marrow and the neural stem cells were isolated from ganglion eminence of rat embryo 14 days. The Mesenchymal stem cells were injected 1 day after middle cerebral artery occlusion (MCAO) and the neural stem cells transplanted 7 day after MCAO. After 28 days, the neurological outcomes and brain lesion volumes were evaluated. Also, the activity of Caspase 3 was assessed in different groups. RESULT: The group which received combination cell therapy had better neurological examination and less brain lesion. Also the combination cell therapy group had the least Caspase 3 activity among the groups. CONCLUSIONS: The combination cell therapy is more effective than Mesenchymal stem cell therapy and neural stem cell therapy separately in treating the brain stroke in rats.

5.
World J Plast Surg ; 4(1): 40-9, 2015 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-25606476

RESUMEN

BACKGROUND: Neck reconstruction is considered as one of the most important surgeries in cosmetic and reconstructive surgery. The present study aimed to assess the results of reconstructive surgery of extensive face and neck burning scars using tissue expanders. METHODS: This descriptive prospective study was conducted on 36 patients with extensive burning scars on the neck and face. Operation for tissue expander insertion was performed and tissue distension started two or three weeks later, depending on the patients' incisions. After sufficient time for tissue expansion, while removing the expander and excision of the lesion, the expanded flap was used to cover the lesion. Overall, 43 cosmetic surgeries were done. RESULTS: Rectangular expanders were employed in most patients (73.81%) and were located in the neck in most of them (60.78%). Complications were detected in five patients (13.89%), with exposure of the prosthesis being the most common one. Scar tissues at the reconstruction site and the flap donor site were acceptable in 94.44% and 98.18% of the cases, respectively. Overall, most of the patients (77.78%) were satisfied with the operation results.  CONCLUSION: Using tissue expanders in tissue reconstruction of extensive neck and facial burning scars results in highly desirable outcomes.

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