An ancient testis-specific IQ motif-containing H gene regulates specific transcript isoform expression during spermatogenesis.

Spermatogenic cells express more alternatively spliced RNAs than most whole tissues; however, the regulation of these events remains unclear. Here, we have characterized the function of a testis-specific IQ motif-containing H gene (Iqch) using a mutant mouse model. We found that Iqch is essential for the specific expression of RNA isoforms during spermatogenesis. Using immunohistochemistry of the testis, we noted that Iqch was expressed mainly in the nucleus of spermatocyte and spermatid, where IQCH appeared juxtaposed with SRRM2 and ERSP1 in the nuclear speckles, suggesting that interactions among these proteins regulate alternative splicing (AS). Using RNA-seq, we found that mutant Iqch produces alterations in gene expression, including the clear downregulation of testis-specific lncRNAs and protein-coding genes at the spermatid stage, and AS modifications - principally increased intron retention - resulting in complete male infertility. Interestingly, we identified previously unreported spliced transcripts in the wild-type testis, while mutant Iqch modified the expression and use of hundreds of RNA isoforms, favouring the expression of the canonical form. This suggests that Iqch is part of a splicing control mechanism, which is essential in germ cell biology.

Adenylate kinase 9 is essential for sperm function and male fertility in mammals.

Despite passing routine laboratory tests for semen quality, bulls used in artificial insemination exhibit significant variation in fertility. Routine analysis of fertility data identified a dairy bull with extreme subfertility (10% pregnancy rate). To characterize the subfertility phenotype, a range of in vitro, in vivo, and molecular assays were carried out. Sperm from the subfertile bull exhibited reduced motility and severely reduced caffeine-induced hyperactivation compared to controls. Ability to penetrate the zona pellucida, cleavage rate, cleavage kinetics, and blastocyst yield after IVF or AI were significantly lower than in control bulls. Whole-genome sequencing from semen and RNA sequencing of testis tissue revealed a critical mutation in adenylate kinase 9 (AK9) that impaired splicing, leading to a premature termination codon and a severely truncated protein. Mice deficient in AK9 were generated to further investigate the function of the gene; knockout males were phenotypically indistinguishable from their wild-type littermates but produced immotile sperm that were incapable of normal fertilization. These sperm exhibited numerous abnormalities, including a low ATP concentration and reduced motility. RNA-seq analysis of their testis revealed differential gene expression of components of the axoneme and sperm flagellum as well as steroid metabolic processes. Sperm ultrastructural analysis showed a high percentage of sperm with abnormal flagella. Combined bovine and murine data indicate the essential metabolic role of AK9 in sperm motility and/or hyperactivation, which in turn affects sperm binding and penetration of the zona pellucida. Thus, AK9 has been found to be directly implicated in impaired male fertility in mammals.

Clinicopathologic Features of Gastrointestinal Tract Langerhans Cell Histiocytosis.

Gastrointestinal (GI) tract involvement by Langerhans cell histiocytosis (LCH) is rare and its clinicopathologic characteristics have only been described in case reports and small series. We reviewed hematoxylin and eosin- and CD1a, S100, and Langerin immunohistochemical-stained slides from 47 patients with well-documented demographic and clinical findings. Our cases included 8 children and 39 adults, with a mean follow-up of 63 months. All pediatric patients had concurrent multisystem LCH, presented with GI symptoms, and showed non-polypoid lesions. Seven (88%) showed multifocal GI disease, including five with multiple GI organ involvement. All sampled lesions from children exhibited infiltrative growth. More than half had died of the disease or manifested persistent LCH at last follow-up. Twenty-five of 39 (64%) adults had LCH involving only the GI tract (single-system), with the remaining 14 (36%) exhibiting multi-system disease. Adult single-system GI LCH was typically encountered incidentally on screening/surveillance endoscopy (72%). Most exhibited isolated colorectal involvement (88%) as a solitary polyp (92%), with a well-demarcated/noninfiltrative growth pattern (70%), and excellent prognosis (100%). In comparison, adult patients with multi-system LCH more frequently presented with GI symptoms (92%, P<0.001), non-colorectal GI site involvement (50%, P=0.02), multifocal GI lesions (43%, P=0.005), non-polypoid lesions (71%, P<0.001), infiltrative histologic growth pattern (78%, P=0.04), and persistent disease (57%, P<0.001). Adult multi-system LCH patients appear to exhibit similar clinicopathologic features to those of pediatric patients. These results demonstrate that adults with single-system LCH involving the GI tract have an excellent prognosis, while multi-system LCH occurring at any age carries an unfavorable prognosis. High-risk features of GI LCH include pediatric age, GI symptomatology, non-colorectal GI involvement, multifocal GI disease, non-polypoid lesions, and infiltrative growth pattern.

Evaluation of fine-needle core biopsy specimens for pancreatic ductal adenocarcinoma: Diagnostic utility and helpful histological features.

AIMS: With the advent of new biopsy devices, fine-needle core biopsy specimens can be obtained from pancreas masses. This study aimed to report the histological spectrum of intrapancreatic adenocarcinoma on fine-needle core biopsy and the accuracy of sampling. METHODS AND RESULTS: We identified 423 SharkCore™ fine-needle core biopsies taken from patients with a high clinical concern for pancreatic adenocarcinoma. For each, we recorded patient age and sex, percentage of diagnostic tissue in each sample and tumour site, size and histological findings. The cases came from 392 patients (193 men, 199 women; mean age 69 years). Median diagnostic tissue amount in the samples was 30%. Common histological findings included desmoplasia (36%), single atypical cells (44%), haphazard glandular growth pattern (68%), nuclear pleomorphism > 4:1 (39%), incomplete gland lumens (18%) and detached atypical epithelial strips (37%). Additional levels were ordered on 143 cases. Final clinical diagnoses associated with the 423 cases were adenocarcinoma (n = 343), pancreatitis (n = 22), intraductal neoplasm or other benign/low-grade process (n = 16) and unknown (n = 42, patients lost to follow-up). Of the adenocarcinoma cases, the diagnosis was established by the evaluated fine-needle core biopsy sample alone in 178, by fine-needle aspiration biopsy alone in 30, by both concurrently in 89 and by subsequent biopsy or resection in 37 cases. Among 68 cases called suspicious on fine-needle core biopsy, 78% ultimately represented adenocarcinoma. CONCLUSIONS: Fine-needle core biopsy allows for histological diagnosis of pancreatic adenocarcinoma, using known histological parameters. Common findings include single atypical cells, desmoplasia, haphazard gland growth and nuclear pleomorphism. Cases interpreted as suspicious often represent malignancy.

Prognostic performance of microscopic size measurements in small invasive carcinomas arising in intraductal papillary mucinous neoplasms of the pancreas.

AIMS: Small invasive carcinomas arising in intraductal papillary mucinous neoplasms (IPMNs) of the pancreas can present as multiple, small foci. In such cases, there is no clear optimal measurement method for determining the invasive size for tumour staging and prognostication. METHODS: In all, 117 small invasive IPMNs (size of largest invasive component ≤2 cm) from seven institutions (2000-2016) were reviewed, and all individual foci of invasive carcinoma were measured. T stages (AJCC 8th edition) based on the largest single focus size (LS), average size of all foci (AS), and total sum of all foci (TS) were examined in association with clinicopathologic parameters and patient outcomes. RESULTS: The cohort comprised IPMNs with invasive tubular-type (n = 82, 70%) and colloid-type (n = 35, 30%) carcinomas. The mean LS, AS, and TS were 0.86, 0.71, and 1.32 cm, respectively. Based on the LS, AS, and TS, respectively, 48, 65, and 39 cases were classified as pT1a; 22, 18, and 11 cases as pT1b; and 47, 34, and 50 cases as pT1c. Higher pT stages based on all measurements were significantly associated with small vessel, large vessel, and perineural invasion (P < 0.05). LS-, AS-, and TS-based pT stages were not significantly associated with recurrence-free survival (RFS) or overall survival (OS) by univariate or multivariate analyses. However, among tubular-type carcinomas, higher LS-, AS-, and TS-based pT stages trended with lower RFS (based on 1-, 3-, and 5-year survival rates). All microscopic measurement methods were most predictive of RFS and OS using a 1.5-cm cutoff, with LS significantly associated with both RFS and OS by univariate and multivariate analysis. CONCLUSIONS: For invasive tubular-type carcinomas arising in IPMN, microscopic size-based AJCC pT stages were not significant predictors of patient outcomes. However, for LS, a size threshold of 1.5 cm was optimal for stratifying both RFS and OS. The AJCC 8th ed. may not be applicable for stratifying small invasive IPMNs with colloid-type histology that generally portend a more favourable prognosis.

Practice patterns for reporting digestive system neuroendocrine neoplasms: results from a large, comprehensive international survey.

AIMS: Criteria for the interpretation of digestive system neuroendocrine neoplasms (NENs) continue to evolve. Although there are some literature recommendations regarding workup and diagnosis of these lesions, different practice patterns exist among pathologists when signing out these specimens. The aim of this study was to assess practice trends among pathologists worldwide when reporting these neoplasms. METHODS AND RESULTS: We created an online survey with multiple questions pertaining to digestive NENs. The results were analysed based on type of practice setting, years of sign-out experience, and practice location. Respondents included 384 practicing pathologists: 70% academic, 30% private practice; 63% gastrointestinal (GI) pathology-subspecialised, 37% not; 39% North American, 42% European, 19% others; 45% with ≤10 years in practice; 55% with >10 years. Some question responses were chosen by the majority (e.g. 85% use both mitotic count and Ki67 index for grading NENs, 82% complete a synoptic, and Ki67 stain even for small incidental appendiceal neuroendocrine tumours [NETs], and 96% utilize the diagnosis of grade 3 NET). However, some questions showed varying responses, including counting mitotic figures, Ki67 stain interpretation, and pancreatic grade 3 NEN workup. Pathologists also had some variability in interpreting regional metastatic foci of small bowel NETs and in choosing blocks for Ki67 staining in multifocal lesions. CONCLUSION: There existed scenarios wherein practice patterns varied despite recommendations in the literature, and there were also scenarios lacking clear guidelines wherein pathologists used varying judgement. This survey highlights current key grey areas in digestive system NEN evaluation, leading to variation in practice patterns.

Cannabis use and episodic memory performance among adolescents: Moderating effects of depression symptoms and sex.

OBJECTIVE: Cannabis use has been linked to poorer episodic memory. However, little is known about whether depression and sex may interact as potential moderators of this association, particularly among adolescents. The current study addresses this by examining interactions between depression symptoms and sex on the association between cannabis use and episodic memory in a large sample of adolescents. METHOD: Cross-sectional data from 360 adolescents (M age = 17.38, SD = .75) were analyzed at the final assessment wave of a two-year longitudinal study. We used the Drug Use History Questionnaire to assess for lifetime cannabis use, and the Computerized Diagnostic Interview Schedule for Children, Fourth edition to assess the number of depression symptoms in the past year. Subtests from the Wechsler Memory Scale, Fourth Edition and the California Verbal Learning Test, Second Edition were used to assess episodic memory performance. RESULTS: The effect of the three-way interaction among cannabis use, depression symptoms, and sex did not have a significant impact on episodic memory performance. However, follow-up analyses revealed a significant effect of the two-way interaction of cannabis use and depression symptoms on episodic memory, such that associations between cannabis use and episodic memory were only significant at lower and average levels of depression symptoms. CONCLUSIONS: Contrary to our hypotheses, we found that as depression symptoms increased, the negative association between cannabis use and episodic memory diminished. Given the use of a predominantly subsyndromic sample, future studies should attempt to replicate findings among individuals with more severe depression.

Optimizing Ozone Disinfection in Water Reuse: Controlling Bromate Formation and Enhancing Trace Organic Contaminant Oxidation.

The use of ozone/biofiltration advanced treatment has become more prevalent in recent years, with many utilities seeking an alternative to membrane/RO based treatment for water reuse. Ensuring efficient pathogen reduction while controlling disinfection byproducts and maximizing oxidation of trace organic contaminants remains a major barrier to implementing ozone in reuse applications. Navigating these challenges is imperative in order to allow for the more widespread application of ozonation. Here, we demonstrate the effectiveness of ozone for virus, coliform bacteria, and spore forming bacteria inactivation in unfiltered secondary effluent, all the while controlling the disinfection byproduct bromate. A greater than 6-log reduction of both male specific and somatic coliphages was seen at specific ozone doses as low as 0.75 O3:TOC. This study compared monochloramine and hydrogen peroxide as chemical bromate control measures in high bromide water (Br- = 0.35 ± 0.07 mg/L). On average, monochloramine and hydrogen peroxide resulted in an 80% and 36% decrease of bromate formation, respectively. Neither bromate control method had any appreciable impact on virus or coliform bacteria disinfection by ozone; however, the use of hydrogen peroxide would require a non-Ct disinfection framework. Maintaining ozone residual was shown to be critical for achieving disinfection of more resilient microorganisms, such as spore forming bacteria. While extremely effective at controlling bromate, monochloramine was shown to inhibit TrOC oxidation, whereas hydrogen peroxide enhanced TrOC oxidation.

The effect of the rs1799931 G857A (G286E) polymorphism on N-acetyltransferase 2-mediated carcinogen metabolism and genotoxicity differs with heterocyclic amine exposure.

Human N-acetyltransferase 2 (NAT2) is subject to genetic polymorphism in human populations. In addition to the reference NAT2*4 allele, two genetic variant alleles (NAT2*5B and NAT2*7B) are common in Europe and Asia, respectively. NAT2*5B possesses a signature rs1801280 T341C (I114T) single-nucleotide polymorphism (SNP), whereas NAT2*7B possesses a signature rs1799931 G857A (G286E) SNP. NAT2 alleles possessing the T341C (I114T) or G857A (G286E) SNP were recombinant expressed in yeast and tested for capacity to catalyze the O-acetylation of the N-hydroxy metabolites of heterocyclic amines (HCAs). The T341C (I114T) SNP reduced the O-acetylation of N-hydroxy-2-amino-3-methylimidazo [4,5-f] quinoline (N-OH-IQ), N-hydroxy-2-amino-3,8-dimethylimidazo [4,5-f] quinoxaline (N-OH-MeIQx) and N-hydroxy- 2-amino-1-methyl-6-phenylimidazo[4,5-b] pyridine (N-OH-PhIP), whereas the G857A (G286E) SNP reduced the O-acetylation of N-OH-IQ and N-OH-MeIQx but not N-OH-PhIP. The G857A (G286E) SNP significantly (p < 0.05) reduced apparent Km toward N-OH-PhIP but did not significantly (p > 0.05) affect apparent Vmax. Cultures of DNA repair-deficient Chinese hamster ovary (CHO) cells transfected with human CYP1A2 and NAT2*4, NAT2*5B or NAT2*7B alleles were incubated with various concentrations of IQ, MeIQx or PhIP and double-stranded DNA damage and reactive oxygen species (ROS) were measured. Transfection with human CYP1A2 did not significantly (p > 0.05) increase HCA-induced DNA damage and ROS over un-transfected cells. Additional transfection with NAT2*4, NAT2*5B or NAT2*7B allele increased both DNA damage and ROS. The magnitude of the increases was both NAT2 allele- and substrate-dependent showing the same pattern as observed for the O-acetylation of the N-hydroxylated HCAs suggesting that both are mediated via NAT2-catalyzed O-acetylation. The results document the role of NAT2 and its genetic polymorphism on the O-acetylation and genotoxicity of HCAs.

N-acetyltransferase 2 genetic polymorphism modifies genotoxic and oxidative damage from new psychoactive substances.

The use of new psychoactive substances (NPS) as drugs of abuse is common and increasingly popular, particularly among youth and neglected communities. Recent studies have reported acute toxic effects from these chemicals; however, their long-term toxicity is unknown. Genetic differences between individuals likely affect the toxicity risk. Arylamine N-acetyltransferase 2 (NAT2) capacity differs among individuals due to genetic inheritance. The goal of the present study is to investigate the gene-environment interaction between NAT2 polymorphism and toxicity after exposure to these chemicals. We measured N-acetylation by human NAT1 and NAT2 and found that N-acetylation of NPS is carried out exclusively by NAT2. Differences in N-acetylation between NAT2*4 (reference allele) and NAT2*5B (common variant allele) were highly significant (p < 0.0001). Using DNA repair-deficient genetically engineered Chinese hamster ovary (CHO cells), expressing human CYP1A2 and either NAT2*4 or NAT2*5B, we measured the induction of DNA double-strand breaks ([Formula: see text]H2Ax) following treatment of the CHO cells with increasing concentrations of NPS. The induction of [Formula: see text]H2Ax showed a NAT2 allele-dependent response, higher in the NAT2*4 vs NAT2*5B alleles (p < 0.05). Induction of oxidative stress (ROS/RNS) was evaluated; we observed NAT2 allele-dependent response for all compounds in concentrations as low as 10 [Formula: see text]M, where NAT2*4 showed increased ROS/RNS vs NAT2*5B (p < 0.05). In summary, NPS are N-acetylated by NAT2 at rates higher in cells expressing NAT2*4 than NAT2*5B. Exposure to psychoactive chemicals results in genotoxic and oxidative damage that is modified by the NAT2 genetic polymorphism.

Effect of N-acetyltransferase 2 genetic polymorphism on 4,4'-methylenebis(2-chloroaniline)-induced genotoxicity and oxidative stress.

4,4'-Methylenebis(2-chloroaniline) or MOCA is an aromatic amine used primarily in polyurethane and rubber industry. MOCA has been linked to hepatomas in animal studies while limited epidemiologic studies reported the association of exposure to MOCA and urinary bladder and breast cancer. We investigated MOCA-induced genotoxicity and oxidative stress in DNA repair-deficient Chinese hamster ovary (CHO) cells stably transfected with human metabolizing enzymes CYP1A2 and N-acetyltransferase 2 (NAT2) variants as well as in rapid, intermediate, and slow NAT2 acetylator cryopreserved human hepatocytes. N-acetylation of MOCA was highest in UV5/1A2/NAT2*4 followed by UV5/1A2/NAT2*7B and UV5/1A2/NAT2*5B CHO cells. Human hepatocytes showed a NAT2 genotype-dependent response with highest N-acetylation in rapid acetylators followed by intermediate and slow acetylators. MOCA induced higher levels of mutagenesis and DNA damage in UV5/1A2/NAT2*7B compared to UV5/1A2/NAT2*4 and UV5/1A2/NAT2*5B cells (p < 0.0001). MOCA also induced higher levels of oxidative stress in UV5/1A2/NAT2*7B cells. MOCA caused concentration-dependent increase in DNA damage in cryopreserved human hepatocytes (linear trend p < 0.001) which was NAT2 genotype dependent i.e., highest in rapid acetylators, lower in intermediate acetylators, and lowest in slow acetylators (p < 0.0001). Our findings show that N-acetylation and genotoxicity of MOCA is NAT2 genotype dependent and suggest that individuals possessing NAT2*7B are at higher risk to MOCA-induced mutagenicity. DNA damage, and oxidative stress. They confirm significant differences in genotoxicity between the NAT2*5B and NAT2*7B alleles, both of which are associated with slow acetylator phenotype.

Kinematic Gait Analysis in People with Mild-Disability Multiple Sclerosis Using Statistical Parametric Mapping: A Cross-Sectional Study.

Multiple sclerosis (MS) is a chronic autoimmune disease that affects the central nervous system. Gait abnormalities, such as altered joint kinematics, are common in people with MS (pwMS). Traditional clinical gait assessments may not detect subtle kinematic alterations, but advances in motion capture technology and analysis methods, such as statistical parametric mapping (SPM), offer more detailed assessments. The aim of this study was to compare the lower-limb joint kinematics during gait between pwMS and healthy controls using SPM analysis. Methods: A cross-sectional study was conducted involving pwMS and healthy controls. A three-dimensional motion capture system was used to obtain the kinematic parameters of the more affected lower limb (MALL) and less affected lower limb (LALL), which were compared using the SPM analysis. Results: The study included 10 pwMS with mild disability (EDSS ≤ 3) and 10 healthy controls. The results showed no differences in spatiotemporal parameters. However, significant differences were observed in the kinematics of the lower-limb joints using SPM. In pwMS, compared to healthy controls, there was a higher anterior pelvis tilt (MALL, p = 0.047), reduced pelvis elevation (MALL, p = 0.024; LALL, p = 0.044), reduced pelvis descent (MALL, p = 0.033; LALL, p = 0.022), reduced hip extension during pre-swing (MALL, p = 0.049), increased hip flexion during terminal swing (MALL, p = 0.046), reduced knee flexion (MALL, p = 0.04; LALL, p < 0.001), and reduced range of motion in ankle plantarflexion (MALL, p = 0.048). Conclusions: pwMS with mild disability exhibit specific kinematic abnormalities during gait. SPM analysis can detect alterations in the kinematic parameters of gait in pwMS with mild disability.

Use of Marijuana: Effect on Brain Health: A Scientific Statement From the American Heart Association.

Marijuana is perceived as a harmless drug, and its recreational use has gained popularity among young individuals. The concentration of active ingredients in recreational formulations has gradually increased over time, and high-potency illicit cannabinomimetics have become available. Thus, the consumption of cannabis in the general population is rising. Data from preclinical models demonstrate that cannabinoid receptors are expressed in high density in areas involved in cognition and behavior, particularly during periods of active neurodevelopment and maturation. In addition, growing evidence highlights the role of endogenous cannabinoid pathways in the regulation of neurotransmitter release, synaptic plasticity, and neurodevelopment. In animal models, exogenous cannabinoids disrupt these important processes and lead to cognitive and behavioral abnormalities. These data correlate with the higher risk of cognitive impairment reported in some observational studies done in humans. It is unclear whether the effect of cannabis on cognition reverts after abstinence. However, this evidence, along with the increased risk of stroke reported in marijuana users, raises concerns about its potential long-term effects on cognitive function. This scientific statement reviews the safety of cannabis use from the perspective of brain health, describes mechanistically how cannabis may cause cognitive dysfunction, and advocates for a more informed health care worker and consumer about the potential for cannabis to adversely affect the brain.

Deletion of arylamine N-acetyltransferase 1 in MDA-MB-231 human breast cancer cells reduces primary and secondary tumor growth in vivo with no significant effects on metastasis.

Arylamine N-acetyltransferase 1 (NAT1) is frequently upregulated in breast cancer. Previous studies showed that inhibition or depletion of NAT1 in breast cancer cells diminishes anchorage-independent growth in culture, suggesting that NAT1 contributes to breast cancer growth and metastasis. To further investigate the contribution of NAT1 to growth and cell invasive/migratory behavior, we subjected parental and NAT1 knockout (KO) breast cancer cell lines (MDA-MB-231, MCF-7, and ZR-75-1) to multiple assays. The rate of cell growth in suspension was not consistently decreased in NAT1 KO cells across the cell lines tested. Similarly, cell migration and invasion assays failed to produce reproducible differences between the parental and NAT1 KO cells. To overcome the limitations of in vitro assays, we tested parental and NAT1 KO cells in vivo in a xenograft model by injecting cells into the flank of immunocompromised mice. NAT1 KO MDA-MB-231 cells produced primary tumors smaller than those formed by parental cells, which was contributed by an increased rate of apoptosis in KO cells. The frequency of lung metastasis, however, was not altered in NAT1 KO cells. When the primary tumors of the parental and NAT1 KO cells were allowed to grow to a pre-determined size or delivered directly via tail vein, the number and size of metastatic foci in the lung did not differ between the parental and NAT1 KO cells. In conclusion, NAT1 contributes to primary and secondary tumor growth in vivo in MDA-MB-231 breast cancer cells but does not appear to affect its metastatic potential.

Gastrointestinal stromal tumors (GISTs) arising in uncommon locations: clinicopathologic features and risk assessment of esophageal, colonic, and appendiceal GISTs.

Risk stratification of gastrointestinal stromal tumors (GISTs) is based on experience with tumors of the stomach, small bowel, and rectum, which are far more common than GISTs of other sites. In this study from 47 institutions, we analyzed GISTs of the esophagus (n = 102), colon (n = 136), and appendix (n = 27) for their size, mitotic rate, morphology, and outcome to determine which criteria predict their behavior. Esophageal GISTs were small (median: 2.5 cm) with spindle cell morphology and a low mitotic rate (mean: 3.6/5 mm2). Twelve (12%) tumors progressed, including 11 with a mitotic rate >5/5 mm2 and one large (6.8 cm) GIST with a mitotic rate of 2/5 mm2. Colonic GISTs were smaller (median: 1.4 cm) and presented with abdominal pain or bleeding in 29% of cases. Most (92%) were composed of spindle cells with a mean mitotic rate of 4.6/5 mm2. Sixteen (12%) tumors progressed: 14 had mitotic rates >5/5 mm2, and two were >5.0 cm with a mitotic rate <5/5 mm2. All but one appendiceal GIST measured <2.0 cm. These tumors were composed of spindle cells with low mitotic rates (<5/5 mm2), and none progressed. Our results suggest that progression risk among esophageal and colonic GISTs is associated with increased mitotic activity (>5/5 mm2) and size >5.0 cm. These findings support the use of size and mitotic rate for prognostication of GISTs in these locations, similar to tumors of the stomach, small bowel, and rectum.

Interval appendicitis shows histological differences from acute appendicitis and may mimic Crohn disease and other forms of granulomatous appendicitis.

AIMS: While patients presenting with clinical signs and symptoms of acute appendicitis (AA) often receive surgical intervention shortly after presentation, certain patients may instead receive non-operative management initially, with appendectomy later. The histology of such interval appendicitis (IA) has only been described in small series. Also, we have noticed a recent increase in the incidence of IA specimens at our institution. METHODS AND RESULTS: We identified appendectomy specimens in our department during 2018 with available haematoxylin and eosin slides and electronic clinical data, and evaluated multiple histological findings. Cases were then divided into AA and IA, based on clinical history (AA if the patient presented to the hospital within 1 week of symptom onset and underwent appendectomy within 48 h; IA if appendectomy was delayed at least 1 week). Changes between groups were compared. The cohort included 165 cases (125 AA, 40 IA). Findings significantly more common in AA included mucosal acute inflammation, mural acute inflammation and acute serositis. Findings significantly more common in IA included Crohn-like mural inflammation, mural fibrosis, goblet cell hyperplasia, granulomas, xanthogranulomatous inflammation, haemosiderin-laden macrophages and granulation tissue. The rate of IA in 2018 (24%) was noticeably higher than in previous years. CONCLUSION: Acute inflammatory changes are more common in AA but can remain present in IA. Mural fibrosis, serosal adhesions, haemosiderin-laden macrophages and granulation tissue suggest IA. Granulomas and xanthogranulomatous inflammation can also be seen in IA, and Crohn-like mural inflammation is not uncommon. These histological patterns can guide signout and prevent diagnostic errors, particularly when clinical information is unavailable.

Interobserver agreement in the diagnosis of anal dysplasia: comparison between gastrointestinal and gynaecological pathologists and utility of consensus conferences.

AIMS: Management of anal dysplasia relies upon the accurate diagnosis of anal biopsy specimens. As institutions move towards subspecialty signout (SSSO), decisions must be made regarding whether to assign anal biopsies to the gastrointestinal (GI) or gynaecological (GYN) pathology service. MATERIALS AND RESULTS: We identified 200 archival tissue biopsies of anal mucosa and circulated them among three GI pathologists and three GYN pathologists. Each pathologist separately scored each biopsy as normal, atypical, low-grade squamous intra-epithelial lesion (LSIL) or high-grade squamous intra-epithelial lesion (HSIL). Every case that was called HSIL by at least one pathologist was stained with p16 immunostain and a 'gold standard' interpretation of whether or not a case represented HSIL was made. The GI pathologists agreed on 97 (49%) cases prior to consensus; the GYN pathologists agreed on 33 (17%). The sensitivities of the three GI pathologists in detecting HSIL against the 'gold standard' were 47, 100 and 21% and for the GYN pathologists the sensitivities were 74, 89 and 84%; the sensitivities of the GI and GYN consensus diagnoses were 74% each. The specificities of the three GI pathologists in detecting HSIL were 99, 90 and 100% and for the GYN pathologists the specificities were 99, 92 and 91%; the specificities of both the GI and GYN consensus diagnoses were 100%. CONCLUSIONS: A mild to moderate degree of interobserver variability exists in the diagnosis of anal dysplasia among pathologists. Our study indicates the utility of some form of consensus conference, as overall agreement among GI pathologists and among GYN pathologists improved following in-person consensus.

Measuring depth of invasion of submucosa - invasive adenocarcinoma in oesophageal endoscopic specimens: how good are we?

AIMS: Emerging data support that submucosa-invasive (pT1b) esophageal adenocarcinomas are cured via endoscopic resection, provided that invasion measures ≤500 µm, they lack other histological features predictive of nodal metastasis and have negative margins. Hence, pathologists' measurement of the depth of submucosal invasion in endoscopic resections may dictate further management (i.e. endoscopic follow-up versus oesophagectomy). In this study, we assessed the interobserver agreement in measuring the depth of submucosal invasion in oesophageal endoscopic resections. METHODS AND RESULTS: Six subspecialised gastrointestinal (GI) pathologists from five academic centres independently measured the depth of submucosal invasion in µm from the deepest muscularis mucosae on 37 oesophageal endoscopic resection slides (round 1 scoring). A consensus meeting with a systematic approach for measuring and discussion of pitfalls was undertaken and remeasuring (round 2 scoring) was conducted. Interobserver agreement was assessed by the intraclass correlation coefficient (ICC) and Cohen's kappa statistics. A lack of agreement was seen among the six reviewers with a poor ICC for both rounds: 1 [0.40, 95% confidence interval (CI) = 0.26-0.56] and 2 (0.49, 95% CI = 0.34-0.63). When measurements were categorised as < or >500 µm, the overall agreement among the six reviewers was only fair for both rounds: 1 (kappa = 0.37, 95% CI = 0.22-0.53) and 2 (kappa = 0.29, 95% CI = 0.12-0.46). CONCLUSIONS: Our study shows a lack of agreement among gastrointestinal pathologists in measuring the depth of submucosal invasion in oesophageal endoscopic resections despite formulating a consensus approach for scoring. If important management decisions continue to be based upon this parameter, more reproducible and concrete guidelines are needed.

Gastrointestinal, hepatic, and pancreatobiliary involvement by plasma cell neoplasms: clinicopathologic correlations in a retrospective cohort of 116 cases.

AIMS: Plasma cell neoplasms (PCNs) may involve the gastrointestinal (GI) tract in two forms: plasmacytoma (PC), an isolated lesion that lacks marrow involvement, and extramedullary myeloma (EMM). However, previous literature on PCNs involving the GI tract, liver, and pancreas is limited. We evaluated the clinicopathologic features of the largest series of GI PCNs to date. METHODS AND RESULTS: Six institutional archives were searched for GI, liver, and pancreas cases involved with PCNs. Medical records were reviewed for clinical and imaging features. Histopathologic features evaluated included involved organ, tumor grade, and marrow involvement. Overall, 116 cases from 102 patients were identified. The tumors most presented as incidental findings (29%). The liver was most involved (47%), and masses/polyps (29%) or ulcers (21%) were the most common findings. Most cases had high-grade morphology (55%). The majority (74%) of GI PCNs were classified as EMM due to the presence of marrow involvement at some point during the disease course, occurring within a year of marrow diagnosis in 46% of patients. PC was classified in 26% of patients due to the lack of marrow involvement. Most (70%) patients died from disease within 10 years (median 14.1) of diagnosis and more than half (58%) died within 6 months. CONCLUSION: PC and EMM involving the GI tract, liver, and pancreas have a wide range of clinicopathologic presentations. Tumors may occur virtually anywhere in the GI tract or abdomen and may precede the diagnosis of marrow involvement. Both GI PC and EMM are associated with a poor prognosis.

Expression of arylamine N-acetyltransferase 2 activity in immortalized human bronchial epithelial cells.

Lung cancer is the leading cause of cancer deaths in the United States with high incidence in tobacco smokers. Arylamine N-acetyltransferase 2 (NAT2) is a xenobiotic enzyme that catalyzes both N- and O-acetylation of carcinogens present in tobacco smoke and contributes towards the genotoxicity of these carcinogens. NAT2 allelic variants result in slow, intermediate, and rapid acetylation phenotypes. A recent meta-analysis reported NAT2 non-rapid (slow and intermediate) phenotypes had a significantly increased risk of lung cancer. NAT2 activity in humans is thought to be restricted to liver and gastrointestinal tract, and no studies to our knowledge have reported the expression of NAT2 activity in immortalized human lung epithelial cells. Given the importance of NAT2 in cancer and inhalation of various carcinogens directly into the lungs, we investigated NAT2 activity in human lung epithelial cells. Both NAT1 and NAT2 protein were detected by "in-cell" Western. Arylamine N-acetyltransferase activity was determined with selective substrates for NAT1 (p-aminobenzoic acid; PABA) and NAT2 (sulfamethazine; SMZ) in the presence and absence of a selective NAT1 inhibitor. PABA N-acetylation (NAT1 activity) in cell protein lysates was abolished in the presence of 25 µM of NAT1 inhibitor whereas SMZ N-acetylation (NAT2) was unaffected. Incubation with the NAT1 inhibitor partially reduced the N-acetylation of ß-naphthylamine and the O-acetylation of N-hydroxy-4-aminobiphenyl consistent with catalysis by both NAT1 and NAT2. Immortalized human lung epithelial cells exhibited dose-dependent N-acetylation of 4-ABP with an apparent KM of 24.4 ± 5.1 µM. These data establish that NAT2 is expressed and functional in immortalized human lung epithelial cells and will help us further our understanding of NAT2 in lung cancer.