PURPOSE: The purpose of this in vitro study was to analyze the toxicity of acrylate-based restorative composite resins filled with hydroxyapatite and a silica/hydroxyapatite combination.
MATERIAL AND METHODS: Five different restorative materials based on bisphenol A-glycidyl methacrylate (bis-GMA) and tri-ethylene glycol dimethacrylate (TEGDMA) were developed: unfilled (H0), hydroxyapatite-filled (H30, H50), and silica/hydroxyapatite-filled (SH30, SH50) composite resins. These were tested for in vitro cytotoxicity by using human bone marrow mesenchymal stromal cells. Surface morphology, elemental composition, and functional groups were determined by scanning electron microscopy (SEM), energy-dispersive x-ray spectroscopy (EDX), and Fourier-transformed infrared spectroscopy (FTIR). The spectra normalization, baseline corrections, and peak integration were carried out by OPUS v4.0 software.
RESULTS: Both in vitro cytotoxicity results and SEM analysis indicated that the composite resins developed were nontoxic and supported cell adherence. Elemental analysis with EDX revealed the presence of carbon, oxygen, calcium, silicon, and gold, while the presence of methacrylate, hydroxyl, and methylene functional groups was confirmed through FTIR analysis.
CONCLUSIONS: The characterization and compatibility studies showed that these hydroxyapatite-filled and silica/hydroxyapatite-filled bis-GMA/TEGDMA-based restorative composite resins are nontoxic to human bone marrow mesenchymal stromal cells and show a favorable biologic response, making them potential biomaterials.
AIM OF THE STUDY: This study is designed to investigate the vasorelaxant effect of Chen pi and to study its pharmacology effects.
MATERIALS AND METHODS: The vasorelaxant effect of water extract of Chen pi (CRW) were evaluated on thoracic aortic rings isolated from Sprague Dawley rats. The fingerprint of Chen pi and the extracts were developed with quantification of hesperidin content by HPTLC.
RESULTS: CRW exhibited the strongest vasorelaxant activity. CRW caused the relaxation of the phenylephrine pre-contracted aortic rings in the presence and absence of endothelium as well as in potassium chloride pre-contracted endothelium-intact aortic ring. The incubation of propranolol (β-adrenergic receptor blocker), atropine (muscarinic receptor blocker), Nω-nitro-L-arginine methyl ester (NO synthase inhibitor), ODQ (sGC inhibitor), indomethacin (COX inhibitor), 4-aminopyridine (KV blocker), barium chloride (Kir blocker), and glibenclamide (KATP blocker) significantly reduced the vasorelaxant effects of CRW. CRW was also found to be active in reducing Ca2+ releases from the sarcoplasmic reticulum and suppressing the voltage-operated calcium channels.
CONCLUSION: The vasorelaxant effect of CRW on rat aorta involves NO/sGC, calcium and potassium channels, muscarinic and β-adrenergic receptors.
OBJECTIVES: To evaluate thermotolerance and antifungal susceptibility of feline Malaysian Sporothrix isolates, compare microdilution (MD) and E-test results, and investigate changes in susceptibility during azole therapy.
METHODS: Sporothrix schenckii sensu stricto was isolated from 44 cats. Thermotolerance was determined via culture at 37°C for 7 days. Susceptibility to itraconazole (ITZ), ketoconazole (KTZ) and terbinafine (TRB) was assessed in 40 isolates by MD; to amphotericin B (AMB), KTZ, ITZ, fluconazole (FLC) and posaconazole (POS) by E-test. Results were statistically compared by Pearson's Product Moment. In eight ketoconazole treated cats, susceptibility testing to itraconazole and ketoconazole was repeated every two months for six months.
RESULTS: Thermotolerance was observed in 36 of 44 (82%) isolates. Assuming that isolates growing at antifungal concentrations ≥4 mg/mL were resistant, all were resistant on E-test to FLC and AMB, 11 (28%) to POS, 6 (15%) to ITZ and 1 (3%) to KTZ. On MD, 27 of 40 (68%) were resistant to TRB, 2 (5%) to ITZ and 3 (8%) to KTZ. There was no correlation between E-test and MD results (KTZ r = 0.10, P = 0.54, and ITZ r = 0.11, P = 0.48). MD values for ITZ and KTZ did not exceed 4 mg/L during KTZ therapy.
CONCLUSION: The majority of feline isolates in Malaysia are thermosensitive. Lack of correlation between E-test and MD suggests that the E-test is unreliable to test antifungal susceptibility for Sporothrix spp. compared to MD. KTZ was the antifungal drug with the lowest MIC. Prolonged KTZ administration may not induce changes in antifungal susceptibility.
RESULT: The recipient transconjugants were resistant to erythromycin, cefpodoxime and were mecA positive. PCR amplification of mecA after mix culture plating on Luria Bertani agar containing 100 μg/mL showed that 75% of the donor and 58.3% of the recipient transconjugants were mecA positive. Additionally, 61.5% of both the donor cells and recipient transconjugants were mecA positive, while 46.2% and 41.75% of both donor and recipient transconjugants were mecA positive on LB agar containing 50 μg/mL and 30 μg/mL respectively.
CONCLUSION: In this study, the direction of transfer of phenotypic resistance as well as mecA was observed to have occurred from the donor to the recipient strains. This study affirmed the importance of horizontal transfer events in the dissemination of antibiotics resistance among different strains of MRSA.