Fracturing quartz produces silica-based radicals on the fracture planes and generates hydroxyl radicals (·OH) in aqueous media.·OH production has been shown to be directly associated with ...quartz-induced cell damage and phagocyte activation in vitro. This·OH production in vitro is inhibited by desferrioxamine mesylate, an Fe chelator, indicating involvement of a Fenton-like reaction. Our objective was to determine if Fe contamination increased the ability of inhaled quartz to cause inflammation and lung injury. Male Fischer 344 rats were exposed 5 hr/day for 10 days to filtered air, 20 mg/ m3freshly milled quartz (57 ppm Fe), or 20 mg/ m3freshly milled quartz contaminated with Fe (430 ppm Fe). High Fe contamination of quartz produced approximately 57% more reactive species in water than quartz with low Fe contamination. Compared to inhalation of quartz with low Fe contamination, high Fe contamination of quartz resulted in increases in the following responses: leukocyte recruitment (537%), lavageable red blood cells (157%), macrophage production of oxygen radicals measured by electron spin resonance or chemiluminescence (32 or 90%, respectively), nitric oxide production by macrophages (71%), and lipid peroxidation of lung tissue (38%). These results suggest that inhalation of freshly fractured quartz contaminated with trace levels of Fe may be more pathogenic than inhalation of quartz alone.
Cell-free DNA (cfDNA) fragmentation is nonrandom, at least partially mediated by various DNA nucleases, forming characteristic cfDNA end motifs. However, there is a paucity of tools for deciphering ...the relative contributions of cfDNA cleavage patterns related to underlying fragmentation factors. In this study, through non-negative matrix factorization algorithm, we used 256 5' 4-mer end motifs to identify distinct types of cfDNA cleavage patterns, referred to as "founder" end-motif profiles (F-profiles). F-profiles were associated with different DNA nucleases based on whether such patterns were disrupted in nuclease-knockout mouse models. Contributions of individual F-profiles in a cfDNA sample could be determined by deconvolutional analysis. We analyzed 93 murine cfDNA samples of different nuclease-deficient mice and identified six types of F-profiles. F-profiles I, II, and III were linked to deoxyribonuclease 1 like 3 (DNASE1L3), deoxyribonuclease 1 (DNASE1), and DNA fragmentation factor subunit beta (DFFB), respectively. We revealed that 42.9% of plasma cfDNA molecules were attributed to DNASE1L3-mediated fragmentation, whereas 43.4% of urinary cfDNA molecules involved DNASE1-mediated fragmentation. We further demonstrated that the relative contributions of F-profiles were useful to inform pathological states, such as autoimmune disorders and cancer. Among the six F-profiles, the use of F-profile I could inform the human patients with systemic lupus erythematosus. F-profile VI could be used to detect individuals with hepatocellular carcinoma, with an area under the receiver operating characteristic curve of 0.97. F-profile VI was more prominent in patients with nasopharyngeal carcinoma undergoing chemoradiotherapy. We proposed that this profile might be related to oxidative stress.
The effects of diesel exhaust particles (DEP) and their components (washed dust and methanol extracts) on the release of proinflammatory cytokines, interleukin-1 (IL-1), and tumor necrosis ...factor-alpha (TNF-α) by alveolar macrophages (AM) were investigated. Rat AM were incubated with 0, 5, 10, 20, 50, or 100 μg/10−6 AM/mL of DEP, methanol-washed DEP, or equivalent concentrations of DEP methanol extracts at 37°C for 24 h. AM-conditioned supernatants were collected and assayed for the activities of IL-1 and TNF-α. At high concentrations, both DEP and DEP methanol extracts were shown to increase IL-1-like activity secreted by AM, whereas methanol-washed DEP had no effect. Neither DEP, methanol-washed DEP, nor DEP methanol extracts was found to stimulate the secretion of TNF-α. The effects of DEP on the release of IL-1 and TNF-α by lipopolysaccharide (LPS)- or interferon-gamma (IFN-γ)-primed AM were also studied. AM were preincubated with various concentrations of DEP for 2 h, then challenged with either 0.1 μg/mL of LPS or 5 units/mL of IFN-γ. DEP inhibited LPS-stimulated production of IL-1 and TNF-α. These inhibitory effects were attributed to the organic extracts of DEP. In contrast, stimulation of AM production of TNF-α by IFN-γ was not affected by DEP exposure. In summary, evidence that DEP enhanced the production of IL-1 by AM in vitro suggests that this proinflammatory cytokine may play a role in the pulmonary response to DEP inhalation. The suppressive response of DEP-pretreated AM to LPS stimulation may be a contributing factor to the impairment of pulmonary defense system after prolonged DEP exposure.
Antibiotics are widely prescribed; however they can cause disturbances in gastrointestinal flora which may lead to reduced resistance to pathogens such as Clostridium difficile (C. difficile). ...Probiotics are live organisms thought to balance the gastrointestinal flora.
The primary objectives were to assess the efficacy and safety of probiotics for preventing Clostridium difficile-associated diarrhea (CDAD) or C. difficile infection in adults and children.
On February 21, 2013 we searched PubMed (1966-2013), EMBASE (1966-2013), Cochrane Central Register of Controlled Trials (The Cochrane Library 2013, Issue 1), CINAHL (1982-2013), AMED (1985-2013), and ISI Web of Science. Additionally, we conducted an extensive grey literature search including contact with industry representatives.
Randomized controlled (placebo, alternative prophylaxis, or no treatment control) trials investigating probiotics (any strain, any dose) for prevention of CDAD, or C. difficile infection were considered for inclusion.
Two authors independently and in duplicate extracted data and assessed risk of bias using pre-constructed, and piloted, data extraction forms. Any disagreements were resolved by a third adjudicator. For articles published in abstract form only, further information was sought by contacting principal authors. The primary outcome was the incidence of CDAD. Secondary outcomes included the incidence of C. difficile infection, adverse events, antibiotic-associated diarrhea (AAD) and length of hospital stay. Dichotomous outcomes (e.g. incidence of CDAD) were pooled using a random-effects model to calculate the relative risk and corresponding 95% confidence interval (95% CI). Continuous outcomes (e.g. length of hospital) were pooled using a random-effects model to calculate the mean difference and corresponding 95% CI. Sensitivity analyses were conducted to explore the impact of missing data on efficacy and safety outcomes. For the sensitivity analyses, we assumed that the event rate for those participants in the control group who had missing data was the same as the event rate for those participants in the control group who were successfully followed. For the probiotic group we calculated effects using the following assumed ratios of event rates in those with missing data in comparison to those successfully followed: 1.5:1, 2:1, 3:1, and 5:1. To explore possible explanations for heterogeneity, a priori subgroup analysis were conducted on probiotic species, dose, adult versus pediatric population, and risk of bias.The overall quality of the evidence supporting each outcome was assessed using the GRADE criteria.
A total of 1871 studies were identified with 31 (4492 participants) meeting eligibility requirements for our review. Overall 11 studies were rated as a high risk of bias due mostly to missing outcome data. A complete case analysis (i.e. participants who completed the study) of those trials investigating CDAD (23 trials, 4213 participants) suggests that probiotics significantly reduce this risk by 64%. The incidence of CDAD was 2.0% in the probiotic group compared to 5.5% in the placebo or no treatment control group (RR 0.36; 95% CI 0.26 to 0.51). Sixteen of 23 trials had missing CDAD data ranging from 5% to 45%. These results proved robust to sensitivity analyses of plausible and worst-plausible assumptions regarding missing outcome data and were similar whether considering trials in adults versus children, lower versus higher doses, different probiotic species, or higher versus lower risk of bias. Our judgment is that the overall evidence warrants moderate confidence in this large relative risk reduction. We downgraded the overall quality of evidence for CDAD to 'moderate' due to imprecision. There were few events (154) and the calculated optimal information size (n = 8218) was more than the total sample size. With respect to the incidence of C. difficile infection, a secondary outcome, pooled complete case results from 13 trials (961 participants) did not show a statistically significant reduction. The incidence of C. difficile infection was 12.6% in the probiotics group compared to 12.7% in the placebo or no treatment control group (RR 0.89; 95% CI 0.64 to 1.24). Adverse events were assessed in 26 studies (3964 participants) and our pooled complete case analysis indicates probiotics reduce the risk of adverse events by 20% (RR 0.80; 95% CI 0.68 to 0.95). In both treatment and control groups the most common adverse events included abdominal cramping, nausea, fever, soft stools, flatulence, and taste disturbance. For the short-term use of probiotics in patients that are not immunocompromised or severely debilitated, we consider the strength of this evidence to be moderate.
Based on this systematic review and meta-analysis of 23 randomized controlled trials including 4213 patients, moderate quality evidence suggests that probiotics are both safe and effective for preventing Clostridium difficile-associated diarrhea.
Rapidly growing tumors often experience hypoxia and nutrient (e.g., glucose) deficiency because of poor vascularization. Tumor cells respond to the cytotoxic effects of such stresses by inducing ...molecular adaptations that promote clonal selection of a more malignant tumor-initiating cell phenotype, especially in the innermost tumor regions. Here, we report a regulatory mechanism involving fucosylation by which glucose restriction promotes cancer stemness to drive drug resistance and tumor recurrence. Using hepatocellular carcinoma (HCC) as a model, we showed that restricted glucose availability enhanced the PERK/eIF2α/ATF4 signaling axis to drive fucosyltransferase 1 (FUT1) transcription via direct binding of ATF4 to the FUT1 promoter. FUT1 overexpression is a poor prognostic indicator for HCC. FUT1 inhibition could mitigate tumor initiation, self-renewal, and drug resistance. Mechanistically, we demonstrated that CD147, ICAM-1, EGFR, and EPHA2 are glycoprotein targets of FUT1, in which such fucosylation would consequently converge on deregulated AKT/mTOR/4EBP1 signaling to drive cancer stemness. Treatment with an α-(1,2)-fucosylation inhibitor sensitized HCC tumors to sorafenib, a first-line molecularly targeted drug used for advanced HCC patients, and reduced the tumor-initiating subset. FUT1 overexpression and/or CD147, ICAM-1, EGFR, and EPHA2 fucosylation may be good prognostic markers and therapeutic targets for cancer patients.
Asphalt fume inhalation has been suspected of affecting immune function in exposed workers. The objective of this study was to evaluate the effect of asphalt exposure on lung immune responses in rats ...using a bacterial infectivity model. Pathogen-free male Sprague-Dawley rats were exposed by inhalation to asphalt fumes (72.6 ± 4.95 mg/m3) or filtered air for 6 h/day for 5 days. One day after the final asphalt exposure, rats were intratracheally inoculated with 5 × 105 Listeria monocytogenes. At 0 (prior to bacterial inoculation), 3, and 7 days after L. monocytogenes instillation, the lungs of each animal were divided. Bronchoalveolar lavage (BAL) was performed on right lungs. The recovered BAL cells were then differentiated and counted, and alveolar macrophage (AM) function was determined. Albumin and lactate dehydrogenase (LDH), two indices of lung injury, were measured in the acellular BAL fluid. To assess bacterial clearance, the left lungs were removed, homogenized, and bacterial colony-forming units (CFUs) were counted. In addition, lung-draining lymph nodes were removed, and lymphocyte phenotype and lymphocyte-induced cytokine production were examined. Asphalt fume exposure did not cause lung injury or inflammation in rats in the absence of infection. Infection induced elevations in AMs, neutrophils (PMNs), albumin, and LDH. Importantly, no significant differences were seen when comparing the asphalt group with the air and nonexposed naive groups at any time before or after infection. Also, asphalt fume inhalation exposure did not affect the rate of pulmonary clearance of L. monocytogenes or AM production of reactive oxygen and nitrogen species. However, asphalt-related increases in lymphocyte secretion of interferon (IFN)-γ, interleukin (IL)-6, and IL-10 were observed at different times after bacterial infection, whereas the total number of lymph-node cells and the percentage of CD4+ and CD8+ cells were not significantly different among the treatment groups. Despite the asphalt-induced changes observed in lymphokine secretion, adaptive immune function seemed to function properly in lung defense against bacterial infection. Because innate nonspecific lung responses and pulmonary clearance of L. monocytogenes were unaffected by asphalt fume exposure, lung defenses were sufficient to control the infection. It was concluded that acute inhalation of asphalt fumes at a high concentration had a minimal effect on lung immune responses to infection in rats.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The mechanism of bleomycin-induced pulmonary fibrosis is not yet clear. Recent studies have shown that alveolar macrophages (AM) can be stimulated by bleomycin in vitro releasing inflammatory ...cytokines, suggesting that the interaction of bleomycin with AM is an important step in the drug-induced fibrotic process. Bleomycin is known to bind DNA and generate oxygen radicals through complexation with Fe2+and oxygen. To provide more insight into the cellular oxidative property of bleomycin, we have developed a fluoromicroscopic method using 2′,7′-dichlorofluorescin diacetate (DCFHDA) as an oxidative fluorescence probe to study the bleomycin-induced intracellular oxidation in rat AM and the inhibition of the oxidation by taurine, a compound known to inhibit the bleomycin-induced fibrosis. Bleomycin at 5 to 20 μg/ml has a moderate stimulatory effect (1.87- to 2.66-fold) on the secretion of superoxide anion. A high concentration of bleomycin (20 μg/ml), however, inhibits cell response to zymosan-induced secretion of superoxide anion. At 4 μg/ml, bleomycin has no effect on cell membrane integrity or morphology but results in a significant increase in intracellular oxidation. This oxidative process is Fe2+-dependent and is accompanied by an increase in intracellular calcium (35 nM). Both the intracellular oxidation and calcium rise induced by internalized bleomycin are inhibited by pretreatment of cells with varying concentrations of taurine (25, 125, and 187.5 μM). The inhibitory effect on intracellular oxidation was found to be 36, 57, and 60%, respectively. These results demonstrate a stimulation-inhibition relationship between bleomycin and taurine on the cellular oxidation at a subcytotoxic dose of bleomycin, suggesting that the oxidative effect of the intracellular bleomycin- Fe2+complex is important in the initiation of the fibrotic process.
Cell-free DNA (cfDNA) fragmentation patterns contain important molecular information linked to tissues of origin. We explored the possibility of using fragmentation patterns to predict ...cytosine-phosphate-guanine (CpG) methylation of cfDNA, obviating the use of bisulfite treatment and associated risks of DNA degradation. This study investigated the cfDNA cleavage profile surrounding a CpG (i.e., within an 11-nucleotide nt window) to analyze cfDNA methylation. The cfDNA cleavage proportion across positions within the window appeared nonrandom and exhibited correlation with methylation status. The mean cleavage proportion was ∼twofold higher at the cytosine of methylated CpGs than unmethylated ones in healthy controls. In contrast, the mean cleavage proportion rapidly decreased at the 1-nt position immediately preceding methylated CpGs. Such differential cleavages resulted in a characteristic change in relative presentations of CGN and NCG motifs at 5′ ends, where N represented any nucleotide. CGN/NCG motif ratios were correlated with methylation levels at tissue-specific methylated CpGs (e.g., placenta or liver) (Pearson’s absolute
r
> 0.86). cfDNA cleavage profiles were thus informative for cfDNA methylation and tissue-of-origin analyses. Using CG-containing end motifs, we achieved an area under a receiver operating characteristic curve (AUC) of 0.98 in differentiating patients with and without hepatocellular carcinoma and enhanced the positive predictive value of nasopharyngeal carcinoma screening (from 19.6 to 26.8%). Furthermore, we elucidated the feasibility of using cfDNA cleavage patterns to deduce CpG methylation at single CpG resolution using a deep learning algorithm and achieved an AUC of 0.93. FRAGmentomics-based Methylation Analysis (FRAGMA) presents many possibilities for noninvasive prenatal, cancer, and organ transplantation assessment.
To investigate the cellular proteolytic activities of various lung pneumocytes using luteinizing hormone releasing hormone (LHRH) and D-Ala6-LHRH as model peptide substrates.
HPLC analysis was used ...to investigate the degradation kinetics of LHRH/D-Ala6-LHRH and to identify their degradation products in isolated lung pneumocytes.
Pulmonary macrophages exhibited the strongest proteolytic activity against LHRH)/D-Ala6-LHRH, followed by type II and type I-like pneumocytes. Three major degradation products of LHRH, namely LHRH 4-10, LHRH 6-10, and LHRH 7-10, were identified in macrophages and type II pneumocytes, whereas in type I-like pneumocytes only the LHRH 7-10 was found. Co-incubation of the cells with known enzyme inhibitors including captopril (an ACE inhibitor), thiorphan (an EP24.11 inhibitor), and EDTA (an EP24.15 inhibitor) inhibited the formation of LHRH 4-10, LHRH 7-10, and LHRH 6-10 respectively. In all cell types, the degradation rate of D-Ala6-LHRH was about 3-8 times lower than that of LHRH. This peptide analog was resistant to degradation by EP24.15 and EP24.11, but was susceptible to ACE.
ACE, EP24.11, and EP24.15 are the major enzymes responsible for the degradation of LHRH in macrophages and type II pneumocytes. The magnitude of peptidase activities in these cell types are: EP24.15 > EP24.11 approximately ACE. No EP24.15 or ACE activity was observed in type I-like pneumocytes and only a weak EP24.11 activity was detected.
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