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Povzetek: Background. Transient hypocalcemia is the most common complication after thyroidectomy. Normomagnesemia is needed for normal secretion of PTH and end-organ responsiveness. Our aim was to determine the influence of infusion of magnesium sulphate before thyroidectomy on the incidence of laboratory and clinical transient hypocalcemia. Methods. In our prospective study, 48 patients (5 men, 43 women; age 22-73 years, median 45 years), who underwent total or near-total thyroidectomy, were randomised preoperatively. Half of them received intravenously 4 ml of 1M magnesium sulphate at the beginning of the surgical procedure, the other half were the control group. Serum concentrations of calcium, ionised calcium, magnesium, phosphate, albumin and PTH were measured prior to surgery and on the first day after surgery. Results. Laboratory postoperative hypocalcemia was present in 27% of patients and 23% of patients had clinical signs and/or symptoms of postoperative hypocalcemia. The concentration of total calcium (p=0.024) and of albumin (p=0.01) was lower in the group that received magnesium sulphate. Conclusions.The patients who received infusion of magnesium sulphate before total thyroidectomy had lower concentration of total serum calcium and albuminin comparison to the control group. There was no statistical differencein the incidence of clinical transient hypocalcemia.
Objavljeno v DiRROS: 08.03.2024; Ogledov: 149; Prenosov: 36
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Povzetek: Purpose. To analyze the possibility of reducing the number of fractions but maintaining the full biological effect of radiotherapy by varying the dose perfraction. Methods. An arbitrary treatment with a constant dose per fractionis substituted for a fully isoeffective combination of a hyperfractionated and hypofractionated treatment. The number of fractions of the combined treatment is derived. All calculations are based on the linear-quadratic model. Conclusions. Standard uniform fractionation requires the fewest fractions. Any variation in dose per fraction increases the number of fractions of a fully isoeffective treatment.
Objavljeno v DiRROS: 08.03.2024; Ogledov: 116; Prenosov: 31
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Povzetek: Background. Silencing oncogenes or other genes that contribute to tumor malignancy and progression offers a promising approach to treating cancer. Specific and efficient silencing of gene expression can be achieved by RNA interference (RNAi) technology using small interfering RNA (siRNA) or short hairpin RNA (shRNA). However, a major challenge in RNAi technology is effective delivery of interfering molecules into target cells. The aim of our study was to evaluate electroporation as a perspective method for efficient invitro transfection of LPB fibrosarcoma cells with plasmid DNA expressing shRNA. Methods. Induction of shRNA-mediated gene silencing by electroporation was determined by fluorescence microscopy, flow cytometry and western blot analysis. The effect of electroporation conditions on cell survival and proliferation was determined by clonogenic assay. Results and conclusions. Ourresults demonstrated that electroporation is a feasible and effective method for delivery of plasmid DNA expressing shRNA into cancer cells in vitro. Electrotransfection of murine LPB fibrosarcoma cells, continuously expressing green fluorescence protein - GFP (LPBGFP), with plasmid DNA encoding shRNA-GFP, reduced GFP expression, which was determined on the protein level, as well as by measurement of GFP fluorescence intensity. A pronounced reduction in GFP expression level was detected from the second to the fifth day after treatment. Moreover, the method is easy to perform and showed low cell damaging effects, which are the most important and preferential factors for further in vivo studies.
Objavljeno v DiRROS: 08.03.2024; Ogledov: 130; Prenosov: 35
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Povzetek: Malignant spinal cord compression (MSCC) is a common and debilitating neurological complication of cancer. Because of the rapid progression of the neurological dysfunction, it is considered a medical emergency that demands a prompt diagnosis and treatment. Almost all of the MSCC are caused by an epidural compression from a tumour or a bony fragment from the collapsed vertebra affected by the metastasis. The most common of the tumours that metastasize to the spinal cord are breast and lung cancer, followed by lymphoma, myeloma, prostate cancer and sarcoma. Conclusions. The most common symptom of MSCC is pain, followed by muscular weakness and autonomic dysfunction. MRI provides the best information regarding MSCC, so all patientsshould have a MRI as soon as possible. If the MRI is contraindicated, patients should have the CT scan done. All patients with newly diagnosed MSCC should receive corticosteroids immediately, even before the definitive diagnosis is made. Other treatment options are surgery with postoperative radiotherapy, radiotherapy only, specific medical therapies according to the tumour type and symptomatic therapy, (mainly opiates). The decision of treatment modalities should be made according to the NOMS (neurological, oncological, mechanical and systemic) principles. In spite of the advances, the treatment is still palliative and many patients with MSCC have a poor prognosis and a short survival.
Objavljeno v DiRROS: 07.03.2024; Ogledov: 171; Prenosov: 33
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Povzetek: Background. Numerous experiments have to be performed before a biomedical application is put to practical use in clinical environment. As a complementary work to in vitro, in vivo and medical experiments, we can use analytical and numerical models to represent, as realistically as possible, real biological phenomena of, in our case, electroporation. In this way we canevaluate different electrical parameters in advance, such as pulse amplitude, duration, number of pulses, or different electrode geometries. Suchnumerical models can contribute significantly to the understanding of an experiment and treatment planning as well as to the design of new electroporation devices and electrodes. Methods. We used commercially available modeling software, based on finite element method. We constructed a model of a subcutaneous tumor during electrochemotherapy (EMAS) and a model ofskin during gene electrotransfer (COMSOL Multiphysics). Tissue-electrode geometries, pulse parameters and currentvoltage measurements from in vivo experiments were used to develop and validate the models. Results. To describeadequately our in vivo observations, a tissue conductivity increase during electroporation was included in our numerical models. The output currents of the models were compared to the currents and the voltages measuredduring in vivo experiments and a good agreement was obtained. Also, when comparing the voltages needed for a successful electropermeabilization assuggested by the models, to voltages applied in experiments and achieving a successful electrochemotherapy or in vivo gene electrotransfer, good agreementcan be observed. Conclusions. Modeling of electric current and electric field distribution during cell and tissue electroporation proves to be helpful in describing different aspects of the process and allowing us to design electrodes and electroporation protocols as a part of treatment planning.
Ključne besede: electroporation, gene electrotransfer, electrochemotherapy, subcutaneous tumor, finite-element method
Objavljeno v DiRROS: 07.03.2024; Ogledov: 171; Prenosov: 44
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