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Here we investigated the bioavailability of black carbon (BC)-derived dissolved organic matter (DOM) for a natural mixed community of marine heterotrophic prokaryotes. We ran an in vitro biodegradation experiment that took place over 3 months and exposed a community of organisms collected in the northwestern Mediterranean Sea (Bay of Marseille, France) to three different soluble fractions of BC prepared in the laboratory from various fossil fuel combustion particulates: standard diesel (D REF ), oxidized diesel (D REF-OX ), and natural samples of ship soot (D SHIP ). Over the course of the three months, we observed significant decreases in the concentrations of dissolved organic carbon (DOC; from 9 to 21 %), dissolved BC (DBC; from 22 to 38 %) and dissolved polycyclic aromatic hydrocarbons (d-PAH; from 24 to 64 %) along with variability in the growth dynamics and activity of the heterotrophic prokaryotic community. The heterotrophic prokaryotic community exposed to D REF-OX treatment showed the highest values of respiration and production and the highest cell abundance, associated with the highest decrease in DOC (21 %) and d-PAH (64 %) concentrations. In the D REF and D SHIP treatments, prokaryotic activity was oriented towards anabolism. D REF treatment led to the highest decrease in DBC concentration (38 %). D SHIP treatment, which presented a substantially different d-PAH and dissolved metals content to the other two treatments, showed the lowest decreases in DOC, DBC and d-PAH concentrations, as well as the lowest prokaryotic activity and biomasses. Our results indicate that BC-derived DOM, including the most condensed fraction of this material, is partly bioavailable and therefore likely to be assimilated by marine prokaryotes. The origin of BC/soot deposited at the ocean surface turns out to be a key parameter that dictates the efficiency of biodegradation of its dissolved fraction by heterotrophic prokaryotes., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Objectives: Current autopsy practice guidelines do not provide a mechanism to identify potential causes of diagnostic error (DE). We used our autopsy data registry to ask if gender or race were related to the frequency of diagnostic error found at autopsy., Methods: Our autopsy reports include International Classification of Diseases (ICD) 9 or ICD 10 diagnostic codes for major diagnoses as well as codes that identify types of error. From 2012 to mid-2015 only 2 codes were used: UNDOC (major undocumented diagnoses) and UNCON (major unconfirmed diagnoses). Major diagnoses contributed to death or would have been treated if known. Since mid-2015, codes included specific diagnoses, i.e. undiagnosed or unconfirmed myocardial infarction, infection, pulmonary thromboembolism, malignancy, or other diagnosis as well as cause of death. Adult autopsy cases from 2012 to 2019 were assessed for DE associated with reported sex or race (nonwhite or white). 528 cases were evaluated between 2012 and 2015 and 699 between 2015 and 2019., Results: Major DEs were identified at autopsy in 65.9 % of cases from 2012 to 2015 and in 72.1 % from 2015 to 2019. From 2012 to 2015, female autopsy cases showed a greater frequency in 4 parameters of DE, i.e., in the total number of cases with any error (p=0.0001), in the number of cases with UNDOC errors (p=0.0038) or UNCON errors (p=0.0006), and in the relative proportions of total numbers of errors (p=0.0001). From 2015 to 2019 undocumented malignancy was greater among males (p=0.0065); no other sex-related error was identified. In the same period some DE parameters were greater among nonwhite than among white subjects, including unconfirmed cause of death (p=0.035), and proportion of total error diagnoses (p=0.0003), UNCON diagnoses (p=0.0093), and UNDOC diagnoses (p=0.035)., Conclusions: Coding for DE at autopsy can identify potential effects of biases on diagnostic error., (© 2023 Walter de Gruyter GmbH, Berlin/Boston.)

Background: Epiploic appendages are fatty peritoneal structures on the external surface of the colon that can infarct and become necrotic in situ or autoamputate., Aims: To describe clinicopathological features of infarcted epiploic appendages (IEAs)., Methods: We reviewed 52 IEAs from 49 patients, recording numerous clinical and pathological characteristics, which were compared across attached and loose IEAs., Results: Twenty-seven IEAs were attached, and 23 were loose; location was unclear in 2. Most were incidental; 3 attached cases caused 'appendagitis'. Most (31, 60%) had a classic 'egg-like' appearance. Common findings included fat necrosis (84%), calcification (67%) and fibrosis (58%). Attached cases had a larger mean size (1.8 cm vs 1.3 cm, p=0.030) and were more often haemorrhagic (37% vs 4%, p=0.0064) and inflamed (67% vs 13%, p=0.0002). Loose cases were more often necrotic (100% vs 74%, p=0.011)., Conclusions: IEAs have different morphology whether they remain attached to peritoneum or become necrotic and detached. Attached cases may cause symptoms., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2022. No commercial re-use. See rights and permissions. Published by BMJ.)

Pseudomembranous colitis is often caused by Clostridium difficile; however, it may also be due to ischemia. To determine if any histologic features could be used to differentiate C difficile from ischemia, 49 biopsies of pseudomembranous colitis (25 from patients with C difficile colitis and 24 from patients with ischemic colitis) were coded, randomized, and evaluated for the presence of numerous variables, including the amount and distribution of mucosal necrosis, lamina propria hyalinization, and atrophic "micro-crypts." Hyalinization of the lamina propria was seen in 19 cases of ischemia but not in C difficile colitis (p < 0.0001). Atrophic-appearing micro-crypts were seen in 18 ischemic cases and 6 C difficile cases (p < 0.0006). Lamina propria hemorrhage, full-thickness mucosal necrosis, and a diffuse microscopic distribution of pseudomembranes were significantly more common in ischemia than C difficile. Endoscopic examination identified pseudomembranes significantly more often with C difficile than ischemia, while the endoscopic appearance of masses or polyps was seen exclusively in cases of ischemia. The presence of a hyalinized lamina propria appeared to be a specific and sensitive marker for ischemia in colon biopsies with pseudomembranes. The presence of atrophic micro-crypts, lamina propria hemorrhage, full-thickness mucosal necrosis, diffuse involvement of all the surface of all biopsies by pseudomembranes, and the endoscopic impression of a localized process, polyp, or mass were also markers of ischemia, while the endoscopic identification of diffuse pseudomembranes favored the diagnosis of C difficile.