The aim of our work was to study (1) the antioxidant properties of lipoic acid (LA) and its reduced metabolite dihydrolipoic acid (DHLA) formed by reduction of LA and (2) the effects of treatment ...with LA and DHLA on (a) K⁺ efflux from human red blood cells and (b) post-ischemic recovery and oxidative stress in isolated perfused rat hearts challenged with an ischemia-reperfusion (IR) sequence. In vitro, we used xanthine and xanthine oxidase to generate superoxide anion, which is not directly measurable by electron paramagnetic resonance (EPR), but specifically oxidizes the spin probe CPH into an EPR-detectable long lasting CPround bullet, filled nitroxide radical. While 5 mM of LA was ineffective in reducing the kinetics of CPround bullet, filled nitroxide formation, DHLA was shown to lessen this rate in a dose-dependent manner and at 30 mM was even more efficient than 300 UI/ml SOD. These results are in agreement with the fact that DHLA is able to directly scavenge superoxide anion. Red cells are a good model to investigate oxidative damage in biological membranes; hence, we used a suspension of erythrocytes incubated with 2,2'-azobis(2-amidinopropane) hydrochloride (AAPH) which generates in vitro free radicals. DHLA provided more effective protection of red cells membranes than LA; DHLA was comparable to Trolox for its antioxidant potency. In vivo, treatment of rats (50 mg/kg/day i.p. for 7 days) with LA induced a slight increase in coronary flow (CF) in isolated perfused hearts, after 30 min of global total ischemia. This effect was not associated with an improvement in contractile function and reduction of myocardial oxidative stress. In conclusion, because of their ability to scavenge free radicals, LA and to an even greater degree DHLA were able to protect the membranes of red blood cells. This finding suggests that LA and DHLA might be useful in the treatment of diseases associated with oxidative stress such as diabetes.
In the early stages of cholestasis, a plethora of mechanisms are considered to contribute to the liver injury: oxidative stress, inflammation, cholangiocytes proliferation and fibrosis. Our study ...aims to investigate the effects of different doses of rosuvastatin (Ro) on experimental bile duct ligation-induced cholestasis. 40 female Wistar rats were randomly divided into 4 groups (n=10): Sham group (laparotomy); BDL group (subjected to bile duct ligation); BDL group treated with Ro (5 mg/bw daily); BDL group treated with Ro (10 mg/bw daily). After 6 days of treatment, in the day 7 after BDL, the animals were sacrificed and we explored hepato-cytolysis, the seric parameters for cholestasis and oxidative stress in plasma, liver, brain and kidneys. Proliferation was investigated by expression of proliferating cell nuclear antigen (PCNA), while inflammation by liver histology, TNFR2 expression and NF-κB induction and activation. To assess fibrosis, we performed Tricrom-Masson staining, transforming growth factor beta-1 (TGF-β1) expression, and for myofibroblast activation, we analyzed α-SMA expression. The administration of Ro in early stages of cholestasis proved to have a beneficial effect by decreasing α-SMA. Ro didn't exert systemic oxidative stress effects, but increased hepatocytolysis, oxidative stress and inflammation in the liver and sustained increased levels of pro-fibrotic cytokine TGF-β1 as well as the number of proliferating cells in ducts and parenchyma. Ro inhibited the induction and the activation of NF-κB, which could be considered a beneficial effect. Further studies must be carried out in order to clearly investigate the balance between risks and benefits for Ro administration in early stages of cholestasis.
Photochemoprevention with natural products represents a new concept in the attempt to reduce the occurrence of skin cancer. However, the molecular mechanisms caused by ultraviolet light exposure ...remain still unclear. The aim of the study was to assess the mechanisms involved in the action of a Calluna vulgaris (Cv) extract, administered in single or multiple doses (10 consecutive days), on UVB-induced skin damage in SKH-1 hairless mice. The extract was topically applied 30 min before each UVB exposure in two doses (2.5 and 4 mg total polyphenolic content/40 μl/cm(2)). At 24 hours after the last treatment, total mitogen-activated protein kinase (p44/42MAPkinase, ERK 1/2), nuclear factor-κB (phospho-NF-κB p65), matrix metalloproteinases (MMP-2, MMP-9) and metalloproteinase inhibitor 1 (TIMP-1) levels were measured in skin using enzyme-linked immunosorbent assay (ELISA). MMP-2 and -9 activities were additionally evaluated by zymography. One topical application of Cv extract reduced the secretion (p<0.004) and inhibited MMP-9 activity UVB-mediated (54% inhibition) via inhibition of NF-κB activation (68% inhibition). In multiple UVB exposures, both doses of Cv extract induced the increase of ERK 1/2 level in correlation with activation of NF-κB and reduced the secretion (p<0.04) and activation of MMP-9 (62% inhibition). Pretreatment with Cv diminished the MMP-2 protein secretion only in one dose UVB-irradiated group (p<0.0001) and decreased TIMP-1 level (p<0.001). These results demonstrated the dual behavior of Cv extract in skin protection against single versus multiple doses of UVB irradiation.
Solar ultraviolet radiation (UV) is a major cause of non-melanoma skin cancer in humans. Photochemoprevention with natural products represents a simple but very effective strategy in the management ...of cutaneous neoplasia. The study investigated the protective activity of Calluna vulgaris (Cv) and red grape seeds (Vitis vinifera L, Burgund Mare variety) (BM) extracts in vivo on UVB-induced deleterious effects in SKH-1 mice skin. Forty SKH-1 mice were randomly divided into 4 groups (n=10): control, UVB irradiated, Cv + UVB irradiated, BM+UVB irradiated. Both extracts were applied topically on the skin in a dose of 4 mg/40 μl/cm(2) before UVB exposure - single dose. The effects were evaluated in skin 24 hours after irradiation through the presence of cyclobutane pyrimidine dimers (CPDs) and sunburn cells, tumor necrosis factor-alpha (TNF-α), interleukin (IL)-6 levels. The antioxidant activity of BM extract was higher than those of Cv extract as determined using stable free radical DPPH assay and ABTS test. One single dose of UVB generated formation of CPDs (p<0.0001) and sunburn cells (p<0.0002) and increased the cytokine levels in skin (p<0.0001). Twenty hours following irradiation BM extract inhibited UVB-induced sunburn cells (p<0.02) and CPDs formation (p<0.0001). Pretreatment with Cv and BM extracts resulted in significantly reduced levels of IL-6 and TNF-α compared with UVB alone (p<0.0001). Our results suggest that BM extracts might be a potential candidate in preventing the damages induced by UV in skin.
The trauma patient on direct oral anticoagulant (DOAC) therapy preinjury presents a challenge in trauma and acute care surgery. Our understanding of these patients is extrapolated from vitamin K ...antagonists. However, DOACs have different mechanisms of action, effects on laboratory coagulation assays, and reversal strategies. Rapid identification of DOACs in the blood will allow timely reversal of factor Xa inhibitors and direct thrombin inhibitors when necessary. The present study evaluated viscoelastic testing to detect and classify DOACs in patient blood samples.
This observational, prospective, open-label, multicenter study used point-of-care viscoelastic testing to analyze blood samples taken from patients with and without DOAC treatment, and healthy volunteers. Antifactor Xa and direct thrombin inhibition (DTI) assays were used to establish reference ranges for viscoelastic testing parameters on the TEG 6s system. These ranges were applied to produce a DOAC identification algorithm for patient blood samples. Internal consistency of the measurements, as well as algorithm sensitivity and specificity, was evaluated.
Using the TEG 6s system, the R parameter reference range was 0.6 minutes to 1.5 minutes for the Antifactor Xa assay and 1.6 minutes to 2.5 minutes for the DTI assay. Our identification algorithm using these ranges for 2.5 minutes or less has sensitives of 98.3% and 100% for factor Xa inhibitor and direct thrombin inhibitor detection, respectively. Specificity was 100%. Both classes of DOAC were detectable, even when samples were collected during the "trough" between doses of medication.
Point-of-care viscoelastic testing with TEG 6s can detect and classify DOACs with high sensitivity and specificity. This tool can be used to better determine the need for reversal in trauma and acute care surgery patients and guide optimal surgical timing in the acute setting.
Prognostic and epidemiological study, level II.
Photodynamic therapy (PDT) mediated by oxidative stress causes direct tumor cell damage as well as microvascular injury. To improve this treatment new photosensitizers are being synthesized and ...tested. We evaluated the effects of PDT with 5,10,15,20-tetrakis(4-methoxyphenyl)-porphyrin (TMPP) and its zinc complex (ZnTMPP) on tumor levels of malondialdehyde (MDA), reduced glutathione (GSH) and cytokines, and on the activity of caspase-3 and metalloproteases (MMP-2 and -9) and attempted to correlate them with the histological alterations of tumors in 3-month-old male Wistar rats, 180 ± 20 g, bearing Walker 256 carcinosarcoma. Rats were randomly divided into five groups: group 1, ZnTMPP+irradiation (IR) 10 mg/kg body weight; group 2, TMPP+IR 10 mg/kg body weight; group 3, 5-aminolevulinic acid (5-ALA+IR) 250 mg/kg body weight; group 4, control, no treatment; group 5, only IR. The tumors were irradiated for 15 min with red light (100 J/cm², 10 kHz, 685 nm) 24 h after drug administration. Tumor tissue levels of MDA (1.1 ± 0.7 in ZnTMPP vs 0.1 ± 0.04 nmol/mg protein in control) and TNF-α (43.5 ± 31.2 in ZnTMPP vs 17.3 ± 1.2 pg/mg protein in control) were significantly higher in treated tumors than in controls. Higher caspase-3 activity (1.9 ± 0.9 in TMPP vs 1.1 ± 0.6 OD/mg protein in control) as well as the activation of MMP-2 (P < 0.05) were also observed in tumors. These parameters were correlated (Spearman correlation, P < 0.05) with the histological alterations. These results suggest that PDT activates the innate immune system and that the effects of PDT with TMPP and ZnTMPP are mediated by reactive oxygen species, which induce cell membrane damage and apoptosis.
Non vitamin K oral anticoagulants (NOACs) do not require regular monitoring but information about their pharmacodynamic effect may be importantin situations like trauma, stroke oremergent surgery. ...Currently, no standardized point-of-care test is available to evaluate the anticoagulant effects of NOACs. We evaluated the anticoagulant effect of NOACs with the next generation point-of-care TEG assay (TEG® 6S) based on a fully-automated thrombelastography system. We used two TEG® 6S assays, the DTI assay and Anti-Factor Xa (AFXa) assay, to detect anticoagulant effects and classify NOACs. Blood from healthy volunteers (n = 26) was used to obtain a baseline reference range. Data derived from patients on factor Xa inhibitors (FXi) (rivaroxaban and apixaban) (n = 39), and direct thrombin inhibitors (DTIs) (dabigatran) (n = 25) were compared against the reference range for detection of drug effect and drug classification. TEG®6s R-time highly correlated to each NOAC. Presence of NOACs caused elongation of R-time on the AFXa assay compared to the reference range (4.3 ± 1.7 vs. 1.3 ± 0.3 min. for FXi, p < 0.001 and 3.5 ± 1.2 vs. 1.3 ± 0.3 min. for DTI, p < 0.001). R-time on the DTI assay was elongated only in presence of a DTI (3.4 ± 1.0 vs. 1.5 ± 0.2 min, p < 0.001). The cutoff for detection of a DTI effect was an R time of 1.9 min and for anti-Xa effect was 1.95 min. For detection of NOAC therapy, there was ≥92% sensitivity and ≥95% specificity. The automated TEG®6s NOAC assay may be an effective tool to identify an anticoagulant effect from NOAC therapy and facilitate care of patients with bleeding or at risk of bleeding in the event of needing emergency surgery.
A less-studied aspect of radiation therapy and medical dosimetry education is experiential learning through attendance at interprofessional conferences. University of North Carolina radiation therapy ...and medical dosimetry students regularly attended morning conferences and daily pretreatment peer review, including approximately 145 hours of direct interaction with medical attending physicians and residents, medical physicists, and other faculty. We herein assessed the effect of their participation in these interprofessional conferences on knowledge and communication. The students who graduated from our radiation therapy and medical dosimetry programs who were exposed to the interprofessional education initiative were compared with those who graduated in the previous years. The groups were compared with regard to their knowledge (as assessed by grades on end-of-training examinations) and team communication (assessed via survey). The results for the 2 groups were compared via exact tests. There was a trend for the examination scores for the 2012 cohort to be higher than for the 2007 to 2011 groups. Survey results suggested that students who attended the interprofessional education sessions were more comfortable speaking with attending physicians, residents, physicists, and faculty compared with earlier students who did not attend these educational sessions. Interprofessional education, particularly vertical integration, appears to provide an enhanced educational experience both in regard to knowledge (per the examination scores) and in building a sense of communication (via the survey results). Integration of interprofessional education into radiation therapy and medical dosimetry educational programs may represent an opportunity to enrich the learning experience in multiple ways and merits further study.
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