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Povzetek: Background. Electrochemotherapy is a tumour ablation modality, based on electroporation of the cell membrane, allowing non-permeant anticancer drugs to enter the cell, thus augmenting their cytotoxicity by orders of magnitude. In preclinical studies, bleomycin and cisplatin proved to be the most suitable for clinical use. Intravenous administration of cisplatin for electrochemotherapy is still not widely accepted in the clinics, presumably due to its lower antitumor effectiveness, but adjuvant therapy by immunomodulatory or vascular-targeting agents could provide a way for its potentiation. Hence, the aim of the present study was to explore the possibility of adjuvant tumour necrosis factor % (TNF-%) therapy to potentiate antitumor effectiveness of electrochemotherapy with intravenous cisplatin administration in murine sarcoma. Materials and methods. In vivo study was designed to evaluate the effect of TNF-% applied before or after the electrochemotherapy and to evaluate the effect of adjuvant TNF-% on electrochemotherapy with different cisplatin doses. Results. A synergistic interaction between TNF-% and electrochemotherapy was observed. Administration of TNF-% before the electrochemotherapy resulted in longer tumour growth delay and increased tumour curability, and was significantly more effective than TNF-% administration after the electrochemotherapy. Tumour analysis revealed increased platinum content in tumours, TNF-% induced blood vessel damage and increased tumour necrosis after combination of TNF-% and electrochemotherapy, indicating an anti-vascular action of TNF-%. In addition, immunomodulatory effect might have contributed to curability rate of the tumours. Conclusion. Adjuvant intratumoural TNF-% therapy synergistically contributes to electrochemotherapy with intravenous cisplatin administration. Due to its potentiation at all doses of cisplatin, the combined treatment is predicted to be effective also in tumours, where the drug concentration is suboptimal or in bigger tumours, where electrochemotherapy with intravenous cisplatin is not expected to be sufficiently effective.
Ključne besede: electrochemotherapy, TNF, adjuvant immunotherapy, cisplatin
Objavljeno v DiRROS: 17.04.2024; Ogledov: 84; Prenosov: 14
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Povzetek: In this paper, we present the mechanisms of premature fracture of modular neck stems in two case studies: (I) when the neck and stem are both made of the same Ti6Al4V alloy, and (II) when the neck and stem are made from two different alloys, CoCrMo and Ti6Al4V alloy. Our study integrates two orthopedic patients who have undergone primary uncemented THA for usual indications in two orthopedic centers (Community Health Centre and University Medical Centre). Both centers are part of the national public health care system. Both surgeries were performed by two skilled orthopedic surgeons with more than 10 years of experience in THA. The survivorship of the modular neck of cast CoCrMo alloy was 24 months. The survivorship of the modular neck from Ti6Al4V alloy was 84 months. Multivariate analyses were performed to assess the differences in the fretting, corrosion, and fatigue of the two prematurely failed modular neck stems: stereo light microscopy (SLM), scanning electron microscopy (SEM), X-ray energy-dispersive spectroscopy (EDS), and electron backscatter diffraction (EBSD). Patient demographic information, including sex, age, body mass index, survivorship of implants, and reason for the revision, was collected from medical records. We found that fretting and fatigue occurred on both neck-stem retrievals due to additional galvanic corrosion, but the CoCrMo/Ti6Al4V alloy system suffered more corrosion due to additional galvanic corrosion and fractured earlier than the Ti6Al4V/Ti6Al4V metal alloy system. Both metallic alloy systems used in this application are known to be highly corrosion-resistant, but the bio-tribo-corrosion processes need to be understood in detail and characterized so that appropriate improvements in design and materials can be made.
Ključne besede: total hip arthroplasty, modular neck, Ti6Al4V alloy, CoCrMo alloy, corrosion
Objavljeno v DiRROS: 07.02.2024; Ogledov: 228; Prenosov: 125
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Ključne besede: Ti6Al7Nb implant alloy cementless hip endoprostheses, roughness, Al2O3 grit blasting, surface and subsurface implant contamination, cytotoxicity, aseptic loosening, infection, osseointegration
Objavljeno v DiRROS: 01.02.2024; Ogledov: 168; Prenosov: 70
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Ključne besede: onkologija, bolniki, nasveti
Objavljeno v DiRROS: 22.11.2023; Ogledov: 317; Prenosov: 131
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Povzetek: The surface, corrosion and wear properties of new and in vivo exposed nickel titanium (NiTi) and stainless steel (SS) archwires used in orthodontic treatment were investigated. Electrochemical and tribo-electrochemical tests in artificial saliva were performed in order to define corrosion properties and to estimate wear rate of new and in vivo exposed NiTi and SS archwires. The surface chemical analysis of the passive film on the NiTi and SS archwires before and after tribocorrosion tests was performed by Auger Electron Spectroscopy (AES). In vivo exposed NiTi and SS archwires had better electrochemical properties than new archwires due to the protective nature of oral deposits. Total wear and coefficients of friction were higher among in vivo exposed archwires and higher in NiTi archwires in comparison to SS archwires. The estimated thickness of the TiO2 passive film on as-received NiTi is 8 nm, while the passive Cr2O3 film on as-received SS is just 1–2 nm. On in vivo exposed NiTi archwire, a 60–80 nm thick organic film/dental plaque was observed, and on SS, it was thinner, at about 60 nm. This research shows the importance of combining AES with electrochemical testing, to characterize tribocorrosive properties of NiTi and SS orthodontic archwires.
Ključne besede: archwires, NiTi, stainless steel, wear
Objavljeno v DiRROS: 24.08.2023; Ogledov: 252; Prenosov: 108
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