Wildfire and African dust aerosol oxidative potential, exposure and dose in the human respiratory tract.

Exposure to wildfire smoke and dust can severely affect air quality and health. Although particulate matter (PM) levels and exposure are well-established metrics linking to health outcomes, they do not consider differences in particle toxicity or deposition location in the respiratory tract (RT). Usage of the oxidative potential (OP) exposure may further shape our understanding on how different pollution events impact health. Towards this goal, we estimate the aerosol deposition rates, OP and resulting OP deposition rates in the RT for a typical adult Caucasian male residing in Athens, Greece. We focus on a period when African dust (1-3 of August 2021) and severe wildfires at the northern part of the Attika peninsula and the Evia island, Greece (4-18 of August 2021) affected air quality in Athens. During these periods, the aerosol levels increased twofold leading to exceedances of the World Health Organization (WHO) [15(5) µg m-3] PM10 (PM2.5) air quality standard by almost 100 %. We show that the OP exposure is 1.5-times larger during the wildfire smoke events than during the dust intrusion, even if the latter was present in higher mass loads - because wildfire smoke has a higher specific OP than dust. This result carries two important implications: OP exposure should be synergistically used with other metrics - such as PM levels - to efficiently link aerosol exposure with the resulting health effects, and, certain sources of air pollution (in our case, exposure to biomass burning smoke) may need to be preferentially controlled, whenever possible, owing to their disproportionate contribution to OP exposure and ability to penetrate deeper into the human RT.

Canadian Biomass Burning Aerosol Properties Modification during a Long-Ranged Event on August 2018.

The aim of this paper is to study the spatio-temporal evolution of a long-lasting Canadian biomass burning event that affected Europe in August 2018. The event produced biomass burning aerosol layers which were observed during their transport from Canada to Europe from the 16 to the 26 August 2018 using active remote sensing data from the space-borne system Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO). The total number of aerosol layers detected was 745 of which 42% were identified as pure biomass burning. The remaining 58% were attributed to smoke mixed with: polluted dust (34%), clean continental (10%), polluted continental (5%), desert dust (6%) or marine aerosols (3%). In this study, smoke layers, pure and mixed ones, were observed by the CALIPSO satellite from 0.8 and up to 9.6 km height above mean sea level (amsl.). The mean altitude of these layers was found between 2.1 and 5.2 km amsl. The Ångström exponent, relevant to the aerosol backscatter coefficient (532/1064 nm), ranged between 0.9 and 1.5, indicating aerosols of different sizes. The mean linear particle depolarization ratio at 532 nm for pure biomass burning aerosols was found equal to 0.05 ± 0.04, indicating near spherical aerosols. We also observed that, in case of no aerosol mixing, the sphericity of pure smoke aerosols does not change during the air mass transportation (0.05-0.06). On the contrary, when the smoke is mixed with dessert dust the mean linear particle depolarization ratio may reach values up to 0.20 ± 0.04, especially close to the African continent (Region 4).

Screening of the DNA mismatch repair genes MLH1, MSH2 and MSH6 in a Greek cohort of Lynch syndrome suspected families.

BACKGROUND: Germline mutations in the DNA mismatch repair genes predispose to Lynch syndrome, thus conferring a high relative risk of colorectal and endometrial cancer. The MLH1, MSH2 and MSH6 mutational spectrum reported so far involves minor alterations scattered throughout their coding regions as well as large genomic rearrangements. Therefore, a combination of complete sequencing and a specialized technique for the detection of genomic rearrangements should be conducted during a proper DNA-testing procedure. Our main goal was to successfully identify Lynch syndrome families and determine the spectrum of MLH1, MSH2 and MSH6 mutations in Greek Lynch families in order to develop an efficient screening protocol for the Greek colorectal cancer patients' cohort. METHODS: Forty-two samples from twenty-four families, out of which twenty two of Greek, one of Cypriot and one of Serbian origin, were screened for the presence of germline mutations in the major mismatch repair genes through direct sequencing and MLPA. Families were selected upon Amsterdam criteria or revised Bethesda guidelines. RESULTS: Ten deleterious alterations were detected in twelve out of the twenty-four families subjected to genetic testing, thus our detection rate is 50%. Four of the pathogenic point mutations, namely two nonsense, one missense and one splice site change, are novel, whereas the detected genomic deletion encompassing exon 6 of the MLH1 gene has been described repeatedly in the LOVD database. The average age of onset for the development of both colorectal and endometrial cancer among mutation positive families is 43.2 years. CONCLUSION: The mutational spectrum of the MMR genes investigated as it has been shaped by our analysis is quite heterogeneous without any strong indication for the presence of a founder effect.

Wireless capsule endoscopy in children: a study to assess diagnostic yield in small bowel disease in paediatric patients.

BACKGROUND AND AIM: Small bowel disease in the paediatric population is varied and to date has relied on indirect l modalities such as small bowel follow-through with attendant radiation exposure. Wireless capsule endoscopy (WCE) has the potential to provide a safer and more effective means of investigating the paediatric small bowel. The aim of our study was to prospectively assess the diagnostic yield of WCE compared with standard investigation in children with suspected small bowel disease. METHODS: Twenty-eight consecutive patients, median age 12.5 y (range, 9.4-15.9) with suspected small bowel disease were investigated with WCE. This included 16 patients with suspected small bowel Crohn disease (CD) (10 newly diagnosed; 6 known cases), 6 with obscure or occult gastrointestinal bleeding (GIB), 3 with Peutz-Jegher polyposis (PJP), 2 with protein-losing enteropathy and 1 with recurrent abdominal pain. All of the patients had preceding upper gastrointestinal endoscopy (OGD) and ileocolonoscopy, and 24 had a barium meal and follow-through (BMFT). Images were downloaded and analysed and results compared with the endoscopic and radiological findings. RESULTS: Three patients were unable to swallow the capsule (1 CD, 1 PJP and 1 GIB). Two of these patients (1 GIB, 1 PJP) had the capsule placed in the stomach endoscopically and completed the WCE uneventfully thereafter. In 3 patients (CD group) the capsule remained in the stomach and/or proximal duodenum and no small bowel images were obtained. Hence, 24 patients had successful completion of the WCE through the small bowel, 23 of whom had clinically relevant findings identified. In all patients with CD who had successful WCE studies (12/16), small bowel disease was identified (11/12 active disease, 1/12 chronic disease). A possible small bowel bleeding source was identified in all 6 patients with GIB. Two patients with GIB also underwent push enteroscopy and 1 of these had a bleeding source identified. The 2 patients with protein-losing enteropathy had extensive patchy lymphangiectasia of the jejunum and ileum, not detected at OGD. The patient with abdominal pain had an intussusception of the upper jejunum. The 2 PJP patients had small bowel polyps identified, which were not detected at BMFT. WCE was more sensitive for small bowel pathology than both BMFT (19 vs 5; 26% sensitivity compared with WCE) and endoscopic investigations (23 vs 10; 43.4% sensitivity compared with WCE). Two patients with CD had delayed capsule transit. CONCLUSIONS: WCE led to a positive alteration in management in 18/24 (75%) of patients whose small bowel was examined by WCE and in 18/28 (64.3%) who were admitted to the study. WCE was safe, well tolerated, and more sensitive than radiological and standard endoscopic modalities in the detection of small bowel CD distribution, GIB source, and presence of polyps in children.

Molecular characterization of rectal mucosa-associated bacterial flora in inflammatory bowel disease.

BACKGROUND: Colorectal bacteria may play a role in the pathogenesis of inflammatory bowel disease (IBD). To test the hypothesis that, in affected patients, the numbers of potentially protective mucosal bacteria might be reduced and pathogenic species increased, we compared rectal mucosa-associated flora in patients with IBD and normal controls. METHODS: Snap-frozen rectal biopsies taken at routine diagnostic colonoscopy from 33 patients with ulcerative colitis, 6 patients with Crohn's disease, and 14 controls with normal colonoscopy were processed, and individual bacterial groups were counted using fluorescent in situ hybridization. RESULTS: Bacteria were mostly found apposed to the epithelial surface and within crypts. Epithelium-associated counts of bifidobacteria in active [median 15/mm of epithelial surface (range, 4-56), n = 14] and quiescent ulcerative colitis [26/mm (range, 11-140), n = 19] were lower than in controls [56/mm (range, 0-144), n = 14; P = 0.006 and P = 0.03, respectively]. Conversely, epithelium-associated Escherichia coli counts were higher in active [82/mm (range, 56-136)] than inactive ulcerative colitis [6/mm (range, 0-136), P = 0.0001] or controls [0/mm (range, 0-16), P < 0.0001]. Epithelium-associated clostridia counts were also higher in active [3/mm (range, 0-9)] than inactive colitis [0/mm (range, 0-9), P = 0.03] or controls [0/mm (range, 0-1); P = 0.0007]. Epithelium-associated E. coli counts were higher in Crohn's disease [42/mm (range, 3-90), n = 6] than controls (P = 0.0006). E. coli were also found as individual bacteria and in clusters in the lamina propria in ulcerative colitis and Crohn's disease but in none of the controls (P < 0.01). Numbers of Lactobacillus and Bacteroides showed no differences between patient groups. CONCLUSIONS: The reduction in mucosa-associated bifidobacteria and increase in E. coli and clostridia in patients with IBD supports the hypothesis that an imbalance between potentially beneficial and pathogenic bacteria may contribute to its pathogenesis.

Enteric infection in relapse of inflammatory bowel disease: importance of microbiological examination of stool.

OBJECTIVE: Previous reports have suggested that diarrhoeal relapses of inflammatory bowel disease (IBD) may be associated or confused with enteric infection, and that treatment of such infections with appropriate antibiotics may be beneficial. To re-evaluate the suggestion that enteric infection is rare and microbiological testing of stool not routinely necessary in patients presenting with relapse of IBD, we have reviewed the incidence of concurrent infection in patients presenting in relapse over a recent 5-year period. METHODS: Stool microbiology results relating to relapses of IBD during the period 1997-2001 were obtained retrospectively. Relapse was confirmed by standard clinical, sigmoidoscopic and laboratory criteria. RESULTS: During the period 1997-2001 there were 237 relapses in 213 patients. Enteric infection was found in 25 (10.5%) relapses in 24 patients; in seven patients, infection was associated with the initial presentation of their IBD. Clostridium difficile toxin was detected in 13 (5.5%) instances; the 12 other infections (5% relapses) were Campylobacter spp. (five), Entamoeba histolytica (three), Salmonella spp. (one), Plesiomonas shigelloides (one), Strongyloides stercoralis (one) and Blastocystis hominis (one). There was a significant association between infection and the need for hospital admission. Of the 13 relapses associated with C. difficile, ten were in outpatients, seven patients had undergone previous antibiotic treatment, and four patients were presenting with IBD for the first time. All relapses resolved satisfactorily after treatment with antibiotics with or without corticosteroids. CONCLUSIONS: The high prevalence of enteric infections, of which C. difficile was the most common, indicates that all patients presenting with relapse of IBD should have stool examined microbiologically.

Oral iron therapy in inflammatory bowel disease: usage, tolerance, and efficacy.

BACKGROUND: Iron deficiency is common in inflammatory bowel disease (IBD). Anecdotal evidence suggests that oral iron is poorly tolerated and may exacerbate disease activity in patients with IBD. AIM The aim of this study was to retrospectively compare usage, tolerance, and efficacy of oral iron therapy in patients with IBD and noninflammatory causes of iron deficiency. METHODS: Case records of 277 patients with IBD and 24 non-IBD iron-deficient control patients covering a 4-year period were retrospectively analyzed. RESULTS: Fifty-three of 277 (19%) of the patients with IBD studied had received oral iron. In only 40% of the patients who had IBD and 63% of the patients who did not (p = not significant) was iron deficiency formally confirmed before treatment. Intolerance to iron was reported in only 25% of the patients who had IBD and 17% of the patients who did not (p = not significant). In only two of eight adequately monitored iron-intolerant patients with IBD was iron therapy associated with an increase in inflammatory markers. When formally checked, iron repletion was successfully achieved as frequently in patients who had IBD (59%) as in patients who did not (45%). CONCLUSION: Iron therapy is often used without a formal diagnosis of iron deficiency having been made, at least in part because of the difficulty in making this diagnosis using ferritin, an acute-phase protein. Patients with IBD are no more intolerant of oral iron than other patients and have similar rates of repletion.

Endoscopic ultrasound-guided biopsy for the diagnosis of focal lesions of the spleen.

OBJECTIVES: Needle biopsy of splenic lesions using computed tomography (CT) or ultrasound (US) is difficult if the size of the lesion is small. It may be dangerous if the lesion is adjacent to the splenic hilum or located peripherally. We used endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) to elucidate the tissue diagnosis of splenic abnormalities. METHODS: EUS-FNA was performed in 12 patients when US- or CT-guided biopsy was inconclusive (n = 5), was not attempted because of small tumor size (0.9-1.4 cm; N = 4), or was considered dangerous (n = 3). A linear echo-endoscope and 22-gauge needles were used for cytology and bacteriology. RESULTS: The age of the patients was 19-68 yr (median 32 yr). Seven patients were male and five female. The size of the lesions was 0.8-4.2 cm (median 1.4 cm). Cytology was inadequate in one patient. Bacteriology was positive for Staphylococcus aureus and Serratia in one patient each, and cultures were positive for Mycobacterium tuberculosis in two patients. A positive diagnosis was made in 10 of 12 patients (83%). Final diagnoses were tuberculosis in two patients, Hodgkin's disease in two, sarcoidosis in two, abscesses in two, metastatic colon cancer in one, and infarction in one. Suspected recurrence of non-Hodgkin's lymphoma was not confirmed in one case. One patient experienced pain after puncture, but no hematoma was demonstrated on subsequent US examination. CONCLUSIONS: EUS-FNA cytodiagnosis in patients with unknown splenic lesions seems feasible, even in very small foci, when CT- or US-guided biopsy fails. Additional material for bacteriology may show benign treatable diseases such as abscesses or tuberculosis.