We prepared antibacterial polystyrene nanoparticles (NPs) with natural photosensitizers from chlorophyll (Chl) extract via a simple nanoprecipitation method using the same solvent for dissolution of the polystyrene matrix and extraction of Chls from spinach leaves. A high photo-oxidation and antibacterial effect was demonstrated on Escherichia coli and was based on the photogeneration of singlet oxygen O2(1Δg), which was directly monitored by NIR luminescence measurements and indirectly verified using a chemical trap. The photoactivity of NPs was triggered by visible light, with enhanced red absorption by Chls. To reduce the quenching effect of carotenoids (β-carotene, lutein, etc.) in the Chl extract, diluted and/or preirradiated samples, in which the photo-oxidized carotenoids lose their quenching effect, were used for preparation of the NPs. For enhanced photo-oxidation and antibacterial effects, a sulfonated polystyrene matrix was used for preparation of a stable dispersion of sulfonated NPs, with the quenching effect of carotenoids being suppressed.
- Publikační typ
- časopisecké články MeSH
- Publikační typ
- abstrakt z konference MeSH
Here we present a new effective antibacterial material suitable for a coating, e.g., surface treatment of textiles, which is also time and financially undemanding. The most important role is played by hydrophobic carbon quantum dots, as a new type of photosensitizer, produced by carbonization of different carbon precursors, which are incorporated by swelling from solution into various polymer matrices in the form of thin films, in particular polyurethanes, which are currently commercially used for industrial surface treatment of textiles. The role of hydrophobic carbon quantum dots is to work as photosensitizers upon irradiation and produce reactive oxygen species, namely singlet oxygen, which is already known as the most effective radical for elimination different kinds of bacteria on the surface or in close proximity to such modified material. Therefore, we have mainly studied the effect of hydrophobic carbon quantum dots on Staphylococcus aureus and the cytotoxicity tests, which are essential for the safe handling of such material. Also, the production of singlet oxygen by several methods (electron paramagnetic spectroscopy, time-resolved near-infrared spectroscopy), surface structures (atomic force microscopy and contact angle measurement), and the effect of radiation on polymer matrices were studied. The prepared material is easily modulated by end-user requirements.
- MeSH
- antibakteriální látky chemie MeSH
- biofilmy MeSH
- biokompatibilní potahované materiály chemie MeSH
- chytré materiály chemie MeSH
- fotosenzibilizující látky chemie MeSH
- hydrofobní a hydrofilní interakce MeSH
- kvantové tečky chemie MeSH
- myši MeSH
- povrchové vlastnosti MeSH
- reaktivní formy kyslíku metabolismus MeSH
- singletový kyslík chemie MeSH
- Staphylococcus aureus MeSH
- uhlík chemie MeSH
- viabilita buněk účinky léků MeSH
- zvířata MeSH
- Check Tag
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- Publikační typ
- tisková chyba MeSH
PURPOSE OF THE STUDY The failure of arthroplasties and above all the issue of infection and its detection have become an ever more frequently discussed problem. The purpose of our study was to determine the frequency and the type of complications after revision total knee arthroplasties and to compare them with the frequency of complications after primary implantations. MATERIAL AND METHODS In our group of patients followed up in the period from January 2007 to December 2016, in 50 patients the revision surgery was performed for aseptic loosening and in 24 patients for deep infection. In the case of revision surgery for aseptic loosening, in 18 patients original sterilised components were used as a spacer, in 6 patients an articulating cement spacer was applied. Only the complications resulting in the performance of further revision were included in the statistics. A total of 13 patients underwent a primary implantation at another centre. The number of revisions and the reason for implant failure were monitored. The results were compared with the frequency of revision surgeries after primary total knee arthroplasty, of which 2,436 were carried out in the referred to period. RESULTS Of 2,436 primary endoprostheses, altogether 3.1 % failed. In 50 (2.1 %) patients aseptic loosening was reported, 24 patients (1 %) suffered from infection. The median time from primary implantation to revision was 11 years for aseptic loosening, 2 years for infection. The most frequent cause of failure was aseptic loosening. In the group of patients who underwent a revision surgery for aseptic loosening, another revision was necessary in 6 cases (12 %), in the group of patients after the two-stage revision surgery for infection, in 9 cases (37.5 %). The most frequent reason for revision surgery was infection - in both the groups this was the reason for 67 % of revision surgeries. DISCUSSION Our results obtained with respect to primary as well as revision surgeries for aseptic loosening correspond with the results reported by other authors. In the case of two-stage revision implantation, the reported frequency of recurrent infections is the same, the frequency of revision surgeries for aseptic causes is slightly lower in our group. The most frequent causes of revision surgery are also in agreement. In the case of primary implantation, the patients most frequently suffer from aseptic loosening, after revision surgeries another revision surgery is most often performed due to infection. The literature refers to studies suggesting the potential use of original components as a spacer with the same success rate as that achieved with the cement spacer. The original components produced good results in two thirds of two-stage revision implantations, which is why we can agree with these studies. CONCLUSIONS The results clearly show a noticeable increase in the frequency of complications in revision surgeries compared to primary surgeries. In comparison with primary implantations, a subsequent revision after the revision implantation for aseptic loosening was necessary three times more frequently, after the two-stage revision implantation for infection it was ten times more frequently. As the most problematic complication can be considered the infection in case of primary as well as revision interventions. It is obvious that aseptic loosening of the primary implant usually occurs later (the median of 11 years) than the development of deep infection (the median of 2 years). Key words: total knee arthroplasty, revision, failure, complications, aseptic loosening, infection, spacer.
- MeSH
- infekce chirurgické rány * etiologie MeSH
- lidé MeSH
- následné studie MeSH
- reoperace MeSH
- selhání protézy MeSH
- totální endoprotéza kolene * škodlivé účinky MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
PURPOSE OF THE STUDY To evaluate the efficacy of the systemic administration of two doses of tranexamic acid (TXA) in total knee (TKA) and hip arthroplasty (THA). MATERIAL AND METHODS The study evaluated a total of 295 patients who underwent total knee and hip arthroplasty for osteoarthritis, prospectively followed up were the patients who had been administered the tranexamic acid (TXA), and this group was subsequently compared against the cohort - control group. Our evaluation was focused on perioperative and postoperative period. The amount of blood loss was monitored during the surgery as well as postoperatively. Moreover, the frequency and the volume of administered allogeneic blood transfusions and in TKA also autotransfusion requirement were observed. The patients postoperative hemoglobin levels were compared in both the groups when the patients were in the ICU and the frequency of all postoperative complications was monitored. The statistical analysis was carried out separately for hip and knee replacement. RESULTS Our study confirmed that the systemic application of tranexamic acid in two 10-15 mg/kg doses in knee arthroplasty resulted in a statistically significant reduction of perioperative and postoperative blood loss, lower frequency of administration of allogeneic blood transfusion, but also in lower frequency in the administration of any transfusion, including autotransfusion. In patients who underwent total hip arthroplasty, the administration of TXA led to a statistically significant reduction of postoperative bleeding. The patients with total knee as well as hip arthroplasty, who had been administered TXA, showed significantly higher haemoglobin levels when transferred from the ICU. No significant difference was found in deep vein thrombosis, pulmonary embolism or other postoperative complications among the study groups. DISCUSSION There is no homogeneity in the already published studies proving the efficacy of TXA in TKA and THA, they differ considerably as to the method of administration of the tranexamic acid. The differences concern the systemic and local application, dosage and time of administration. In some studies, TXA was administered in a single dose only, whereas in other studies it was administered repeatedly, in the form of a bolus or continuously. In our study we confirmed the efficacy of systemic administration of tranexamic acid in two repeated bolus doses of 10-15 mg/kg, namely before the commencement of the surgery and at the end of the surgery. CONCLUSIONS The administration of tranexamic acid in two IV doses of 10-15 mg/kg to patients with total knee and hip arthroplasty has proven to be efficient. A higher efficacy of TXA was reported in TKA and due to routine administration of TXA the postoperative autotransfusion system (ORTHO P.A.S.) ceased to be used in knee replacement surgery. Key words:total hip arthroplasty, total knee arthroplasty, tranexamic acid, blood loss, allogeneic transfusion, autotransfusion, postoperative complications.
Despite great efforts, the design of antibacterial surfaces is still a challenge. In this work, results of structural, mechanical, cytotoxic and antibacterial activities of hydrophobic carbon quantum dots/polydimethylsiloxane surfaces are presented. Antibacterial action of this surface is based on the generation of reactive oxygen species which cause bacteria damage by oxidative stress. At the same time, this surface was not cytotoxic towards the NIH/3T3 cells. Swelling-encapsulation-shrink method is applied for encapsulation of hydrophobic carbon quantum dots in medical grade silicone-polydimethylsiloxane. XPS and photoluminescence spectroscopy analyses confirm that hydrophobic carbon quantum dots have been encapsulated successfully into polydimethylsiloxane polymer matrix. Based on stress-strain test the improvement of mechanical properties of these nanocomposites is established. It is shown by electron paramagnetic resonance spectroscopy and luminescence method that nanocomposite generates singlet oxygen initiated by 470 nm blue light irradiation. Antibacterial testing shows the nanocomposite in the form of foil kills Staphylococcus aureus, Escherichia coli and Klebsiella pneumoniae and is very effective after only a 15 min irradiation.
- MeSH
- dimethylpolysiloxany farmakologie MeSH
- Escherichia coli účinky léků MeSH
- fotochemoterapie metody MeSH
- Klebsiella pneumoniae účinky léků MeSH
- kvantové tečky terapeutické užití MeSH
- myši MeSH
- nanokompozity terapeutické užití MeSH
- povrchové vlastnosti MeSH
- singletový kyslík metabolismus MeSH
- Staphylococcus aureus účinky léků MeSH
- uhlík farmakologie MeSH
- zvířata MeSH
- Check Tag
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Aqueous dispersions of sulfonated polystyrene nanoparticles (average diameter: 30 ± 14 nm) with encapsulated 5,10,15,20-tetraphenylporphyrin (TPP) are promising candidates for antibacterial treatments due to the photogeneration of cytotoxic singlet oxygen species O2(1Δg) under physiological conditions using visible light. The antibacterial effect on gram-negative Escherichia coli was significantly enhanced after the addition of nontoxic potassium iodide (0.001-0.01 M) because photogenerated O2(1Δg) oxidized iodide to I2/I3-, which is another antibacterial species. The improved antibacterial properties were predicted using luminescence measurements of O2(1Δg), transient absorption of TPP triplets and singlet oxygen-sensitized delayed fluorescence (SODF). In contrast to a solution of free photosensitizers, the aqueous dispersion of photoactive nanoparticles did not exhibit any quenching of the excited states after the addition of iodide or any tendency toward aggregation and/or I3--induced photo-aggregation. We also observed a decrease in the lifetime of O2(1Δg) and a significant increase in SODF intensity at higher temperatures, due to the increased oxygen diffusion coefficient in nanoparticles and aqueous surroundings. This effect corresponds with the significantly stronger antibacterial effect of nanoparticles at physiological temperature (37 °C) in comparison with that at room temperature (25 °C).
- MeSH
- antibakteriální látky farmakologie MeSH
- časové faktory MeSH
- Escherichia coli účinky léků MeSH
- fotosenzibilizující látky farmakologie MeSH
- jodidy farmakologie MeSH
- kinetika MeSH
- luminiscence MeSH
- mikrobiální testy citlivosti MeSH
- nanočástice chemie ultrastruktura MeSH
- nanovlákna chemie ultrastruktura MeSH
- teplota * MeSH
- Publikační typ
- časopisecké články MeSH
Úvod: Cílem této práce je srovnání pooperačních výsledků mezi interferenčním šroubem a kortikální závěsnou fixací ToggleLoc pro femorální fixaci štěpu při náhradě předního zkříženého vazu. Materiál a metodika: Zhodnotili jsme pooperační výsledky u 97 pacientů - 55 pacientů s fixací pomocí interferenčního šroubu a 42 pacientů s kortikální závěsnou fixací. Hodnoceny byly pohyb, stabilita a diference předozadní stability kolenního kloubu ve srovnání s druhostranným zdravým kloubem. Dále byly hodnoceny subjektivní dotazníkové formy - Lysholmovo a IKDC skóre. Rozdíly jednotlivých fixací byly zhodnoceny nezávislým statistikem. Výsledky: Replastika byla provedena u tří pacientů v každé skupině. Medián stranových rozdílů ventrální laxity kolena byl 1,7 mm u interferenčního šroubu a 1,85 mm u kortikální závěsné fixace. Rozdíl mezi skupinami byl tedy 0,15 mm. Hodnoty Lysholmova skóre, IDKC skóre, Lachmanův test a omezení pohybu byly mezi sledovanými skupinami obdobné a statisticky nevýznamné. Diskuse: V literatuře jsou popisovány přednosti a nevýhody jednotlivých fixací, avšak při zhodnocení pooperační výsledků většina autorů publikuje obdobné výsledky obou fixací. Stejných výsledků jsme dosáhli i v naší studii. Závěr: V našem souboru jsme dosáhli u obou skupin obdobných pooperačních výsledků a neprokázali jsme statisticky významný rozdíl v pooperačních výsledcích jednotlivých fixací.
Introduction: The aim of this work is to compare postoperative results between interference screws and cortical suspension device ToggleLoc for femoral fixation while replacing anterior cruciate ligament.
- Klíčová slova
- kortikální závěsná fixace, interferenční šroub,
- MeSH
- artroplastiky kloubů metody MeSH
- autologní transplantace MeSH
- dospělí MeSH
- hodnocení výsledků péče pacientem MeSH
- klinická studie jako téma MeSH
- kolenní kloub chirurgie MeSH
- kostní šrouby MeSH
- lidé středního věku MeSH
- lidé MeSH
- mladý dospělý MeSH
- nestabilita kloubu chirurgie MeSH
- poranění předního zkříženého vazu * chirurgie terapie MeSH
- rekonstrukce předního zkříženého vazu * metody MeSH
- rozsah kloubních pohybů MeSH
- šlachy transplantace MeSH
- výsledek terapie MeSH
- Check Tag
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- mladý dospělý MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
The development of effective photosensitizers is particularly attractive for photodynamic therapy of cancer. Three novel porphyrin photosensitizers functionalized with phosphinic groups were synthesized and their physicochemical, photophysical, and photobiological properties were collected. Phosphinic acid groups (R1R2POOH) attached to the porphyrin moiety (R1) contain different R2 substituents (methyl, isopropyl, phenyl in this study). The presence of phosphinic groups does not influence absorption and photophysical properties of the porphyrin units, including the O2(1Δg) productivity. In vitro studies show that these porphyrins accumulate in cancer cells, are inherently nontoxic, however, exhibit high phototoxicity upon irradiation with visible light with their phototoxic efficacy tuned by R2 substituents on the phosphorus centre. Thus, phosphinatophenylporphyrin with isopropyl substituents has the strongest photodynamic efficacy due to the most efficient cellular uptake. We demonstrate that these porphyrins are attractive candidates for photodynamic applications since their photodynamic efficacy can be easily tuned by the R2 substituent.
