Offline Two-Dimensional Liquid Chromatography-Mass Spectrometry for Deep Annotation of the Fecal Metabolome Following Fecal Microbiota Transplantation.

Biological interpretation of untargeted LC-MS-based metabolomics data depends on accurate compound identification, but current techniques fall short of identifying most features that can be detected. The human fecal metabolome is complex, variable, incompletely annotated, and serves as an ideal matrix to evaluate novel compound identification methods. We devised an experimental strategy for compound annotation using multidimensional chromatography and semiautomated feature alignment and applied these methods to study the fecal metabolome in the context of fecal microbiota transplantation (FMT) for recurrent C. difficile infection. Pooled fecal samples were fractionated using semipreparative liquid chromatography and analyzed by an orthogonal LC-MS/MS method. The resulting spectra were searched against commercial, public, and local spectral libraries, and annotations were vetted using retention time alignment and prediction. Multidimensional chromatography yielded more than a 2-fold improvement in identified compounds compared to conventional LC-MS/MS and successfully identified several rare and previously unreported compounds, including novel fatty-acid conjugated bile acid species. Using an automated software-based feature alignment strategy, most metabolites identified by the new approach could be matched to features that were detected but not identified in single-dimensional LC-MS/MS data. Overall, our approach represents a powerful strategy to enhance compound identification and biological insight from untargeted metabolomics data.

Glucagon-Like Peptide-1 Receptor Agonists Do Not Increase Aspiration During Upper Endoscopy in Patients With Diabetes.

BACKGROUND & AIMS: Glucagon-like peptide-1-receptor agonists (GLP1-RAs) have been associated with greater retention of gastric contents, however, there is minimal controlled, population-based data evaluating the potential adverse effects of GLP1-RA in the periprocedural setting. We aimed to determine if there is increased risk of aspiration and aspiration-related complications after upper endoscopy in patients using GLP1-RAs. METHODS: We used a nationwide commercial administrative claims database to conduct a retrospective cohort study of patients aged 18 to 64 with type 2 diabetes who underwent outpatient upper endoscopy from 2005 to 2021. We identified 6,806,046 unique upper endoscopy procedures. We compared claims for aspiration and associated pulmonary adverse events in the 14 days after upper endoscopy between users of GLP1-RAs, dipeptidyl peptidase 4 inhibitors (DPP4is), and chronic opioids. We adjusted for age, sex, Charlson Comorbidity score, underlying respiratory disease, and gastroparesis. RESULTS: We found that pulmonary adverse events after upper endoscopy are rare, ranging from 6 to 25 events per 10,000 procedures. When comparing GLP1-RAs with DPP4i, crude relative risks of aspiration (0.67; 95% CI, 0.25-1.75), aspiration pneumonia (0.95; 95% CI, 0.40-2.29), pneumonia (1.07; 95% CI, 0.62-1.86), or respiratory failure (0.75; 95% CI, 0.38-1.48) were not higher in patients prescribed a GLP1-RA. When comparing GLP1-RAs with opioids, crude relative risks were 0.42 (95% CI, 0.15-1.16) for aspiration, 0.60 (95% CI, 0.24-1.52) for aspiration pneumonia, 0.30 (95% CI, 0.19-0.49) for pneumonia, and 0.24 (95% CI, 0.13-0.45) for respiratory failure. These results were consistent across several sensitivity analyses. CONCLUSIONS: GLP1-RA use is not associated with an increased risk of pulmonary complications after upper endoscopy compared with DPP4i use in patients with type 2 diabetes.

Using Multidimensional Separations to Distinguish Isomeric Amino Acid-Bile Acid Conjugates and Assess Their Presence and Perturbations in Model Systems.

Bile acids play key roles in nutrient uptake, inflammation, signaling, and microbiome composition. While previous bile acid analyses have primarily focused on profiling 5 canonical primary and secondary bile acids and their glycine and taurine amino acid-bile acid (AA-BA) conjugates, recent studies suggest that many other microbial conjugated bile acids (or MCBAs) exist. MCBAs are produced by the gut microbiota and serve as biomarkers, providing information about early disease onset and gut health. Here we analyzed 8 core bile acids synthetically conjugated with 22 proteinogenic and nonproteogenic amino acids totaling 176 MCBAs. Since many of the conjugates were isomeric and only 42 different m/z values resulted from the 176 MCBAs, a platform coupling liquid chromatography, ion mobility spectrometry, and mass spectrometry (LC-IMS-MS) was used for their separation. Their molecular characteristics were then used to create an in-house extended bile acid library for a combined total of 182 unique compounds. Additionally, ∼250 rare bile acid extracts were also assessed to provide additional resources for bile acid profiling and identification. This library was then applied to healthy mice dosed with antibiotics and humans having fecal microbiota transplantation (FMT) to assess the MCBA presence and changes in the gut before and after each perturbation.

Overlapping and unique brain responses to cognitive and response inhibition.

Although cognitive inhibition and response inhibition fall under the umbrella term of inhibition, the question remains whether the two aspects of inhibition engage shared or distinct brain regions. The current study is one of the first to examine the neural underpinnings of cognitive inhibition (e.g. the Stroop incongruency effect) and response inhibition (e.g. "no-go" response) within a single task. Adult participants (n = 77) completed an adapted version of the Simon Task in a 3T MRI scanner. The results demonstrated that cognitive and response inhibition recruited a group of overlapping brain regions (inferior frontal cortex, inferior temporal lobe, precentral cortex, parietal cortex). However, a direct comparison of cognitive and response inhibition revealed that the two aspects of inhibition also engaged distinct, task-specific brain regions (voxel-wise FWE corrected p < 0.05). Cognitive inhibition was associated with increases in multiple brain regions within the prefrontal cortex. On the other hand, response inhibition was associated with increases in distinct regions of the prefrontal cortex, right superior parietal cortex, and inferior temporal lobe. Our findings advance the understanding of the brain basis of inhibition by suggesting that cognitive inhibition and response inhibition engage overlapping but distinct brain regions.

The Clinical Utility and Cost of Routine Staging Exam under Anesthesia for Oral Cavity Squamous Cell Carcinoma.

INTRODUCTION: The standard complete evaluation of patients with head and neck squamous cell carcinoma (HNSCC) has included a staging exam under anesthesia (EUA) since the 1970s. The EUA for all sites of HNSCC has historically consisted of panendoscopy for the purpose of diagnostic biopsy, accurate staging of primary disease, and identification of second primary tumors. However, due to the accessibility of the oral cavity, the sole purpose of EUA for tumors of this site is to identify second primary tumors. Since the EUA became the gold standard for evaluation of HNSCC, there have been significant advancements in less invasive technologies such as CT, PET-CT, MRI, and fiberoptic examination. In this study, we sought to determine the value to patient care and cost-effectiveness of EUA in patients with oral cavity squamous cell carcinoma (OCSCC). METHODS: A retrospective chart review identified 77 patients who underwent EUA for OCSCC. RESULTS: The most common subsites were the oral tongue and floor of mouth (59.7% and 24.7% respectively). All underwent direct laryngoscopy, 94.8% underwent esophagoscopy, and 20.8% underwent flexible transnasal examination in clinic prior to EUA. For 90.9% of patients, the EUA did not change initial T-staging based on clinical examination and imaging. The remaining 9.1% of patients were upstaged after EUA, however this change did not impact the treatment plan. Second primary tumors were identified in 3.9% of patients, all were found in either the oral cavity or oropharynx, and were also identified with clinical examination or imaging. Analysis of patient charges determined an average cost of $8,022.93 per patient under the current paradigm involving EUA, however with a new algorithm eliminating mandatory EUA average cost decreases to $1,448.44. CONCLUSION: Formal EUA has historically been the gold standard for all HNSCC tumors. However, when performed for cases of oral cavity carcinoma, it is safe and cost effective to limit its use to select clinical scenarios.

Giardia and growth impairment in children in high-prevalence settings: consequence or co-incidence?

PURPOSE OF REVIEW: Giardia is a common intestinal parasite worldwide, and infection can be associated with clear, and sometimes persistent symptomatology. However, in children in high-prevalence settings, it is most often not associated with or is perhaps even protective against acute diarrhea. Nonetheless, recent longitudinal studies in high-prevalence settings increasingly identify an association with long-term outcomes that has been difficult to discern. RECENT FINDINGS: Recent studies have made progress in disentangling this apparent paradox. First, prospective, well characterized cohort studies have repeatedly identified associations between Giardia infection, gut function, and child growth. Second, experimental animal and in-vitro models have further characterized the biological plausibility that Giardia could impair intestinal function and subsequently child development through different pathways, depending upon biological and environmental factors. Finally, new work has shed light on the potential for Giardia conspiring with specific other gut microbes, which may explain discrepant findings in the literature, help guide future higher resolution analyses of this pathogen, and inform new opportunities for intervention. SUMMARY: Recent prospective studies have confirmed a high, if not universal, prevalence of persistent Giardia infections in low-and-middle income countries associated with child-growth shortfalls and altered gut permeability. However, the predominance of subclinical infections limits understanding of the true clinical impact of endemic pediatric giardiasis, and global disease burdens remain uncalculated. Integrating the role of Giardia in multipathogen enteropathies and how nutritional, microbial, metabolic, and pathogen-strain variables influence Giardia infection outcomes could sharpen delineations between pathogenic and potentially beneficial attributes of this enigmatic parasite.

Prevalence and Associated Dietary Factors of Rome IV Functional Gastrointestinal Disorders in Rural Western Honduras.

BACKGROUND: The literature is limited regarding the prevalence of functional gastrointestinal disorders (FGIDs) in Central America, and the role of dietary factors. METHODS: The Rome IV diagnostic questionnaire and National Cancer Institute Diet History questionnaire were administered in one-on-one interviews to a distributed cross section of the general adult population of Western Honduras. Our aim was to estimate prevalence of common FGIDs and symptoms and their relationships to dietary habits. RESULTS: In total, 815 subjects were interviewed, of whom 151 fulfilled criteria for an FGID (18.5%). Gastroduodenal FGIDs were noted in 9.4%, with epigastric pain syndrome (EPS) more common than postprandial distress syndrome, 8.5% versus 1.6%. Among bowel disorders, functional abdominal bloating (FAB) was most prevalent (6.3%), followed by irritable bowel syndrome (3.6%), functional diarrhea (FDr; 3.4%), and functional constipation (1.1%). A significant inverse association was noted between regular bean intake and any FGID (OR 0.41, 95% CI 0.27-0.63), driven by IBS and FDr. Vegetable consumption was associated with lower prevalence of functional diarrhea (OR 0.12; 95% CI 0.04-0.35) and any diarrheal disorder (OR 0.11; 95% CI 0.04-0.31). Subjects with a median daily intake of ≥ 4 corn tortillas had 1.75 (95% CI 1.22-2.50) times the odds of having any FGID. CONCLUSIONS: FGIDs were common in this rural low-resource setting in Central America, with an intriguing distribution of specific FGIDs. EPS and FAB were common, but IBS was not. Local dietary factors were associated with specific FGIDs, suggesting that diet may play a role in global variations of FGIDs.

High-throughput amplicon sequencing of the full-length 16S rRNA gene with single-nucleotide resolution.

Targeted PCR amplification and high-throughput sequencing (amplicon sequencing) of 16S rRNA gene fragments is widely used to profile microbial communities. New long-read sequencing technologies can sequence the entire 16S rRNA gene, but higher error rates have limited their attractiveness when accuracy is important. Here we present a high-throughput amplicon sequencing methodology based on PacBio circular consensus sequencing and the DADA2 sample inference method that measures the full-length 16S rRNA gene with single-nucleotide resolution and a near-zero error rate. In two artificial communities of known composition, our method recovered the full complement of full-length 16S sequence variants from expected community members without residual errors. The measured abundances of intra-genomic sequence variants were in the integral ratios expected from the genuine allelic variants within a genome. The full-length 16S gene sequences recovered by our approach allowed Escherichia coli strains to be correctly classified to the O157:H7 and K12 sub-species clades. In human fecal samples, our method showed strong technical replication and was able to recover the full complement of 16S rRNA alleles in several E. coli strains. There are likely many applications beyond microbial profiling for which high-throughput amplicon sequencing of complete genes with single-nucleotide resolution will be of use.

The potential for malignancy from atopic disorders and allergic inflammation: A systematic review and meta-analysis.

OBJECTIVE: While chronic inflammation is a well-established risk factor for malignancy, studies evaluating the relationship between allergic inflammation and cancer have revealed conflicting results. Here, we aimed to assess the association between allergic inflammation in the lung (asthma), skin (eczema) or oesophagus (eosinophilic oesophagitis; EoE) and cancer at the organ site. DESIGN: We conducted a systematic review of the literature to identify observational studies (case-control, cohort and cross-sectional) evaluating the association between asthma and lung cancer, eczema and skin cancer, or EoE and oesophageal cancer. Random-effects meta-analysis was performed to define pooled estimates of effects. DATA SOURCES: PubMed, EMBASE and Web of Science. ELIGIBILITY CRITERIA FOR SELECTION: Included studies evaluated the incidence of cancer. RESULTS: Thirty-two studies met the inclusion criteria, 27 in the lung, four in the skin and one in the oesophagus. Meta-analysis of the three studies with prospective data collection of asthma diagnosis revealed a positive association with incident lung cancer (OR 1.27, 95% CI 1.09-1.44); however, this result was not consistently supported by the larger dataset of retrospective studies (OR 1.37, 95% CI 0.90-1.83). Overall, studies in the lung displayed significant heterogeneity (I2 98%, P < .0001), but no significant effect modification on the association between asthma and lung cancer was identified for the variables of sex, smoking or study design. Meta-analysis could not be applied to the four papers reviewed in the skin, but three suggested an association between eczema and non-melanoma skin cancer, while the remaining study failed to identify an association between melanoma and eczema. A single study meeting inclusion criteria showed no association between EoE and oesophageal malignancy. CONCLUSIONS: The current data cannot exclude the possibility of an association between atopy and malignancy the lung, skin and oesophagus. The relationship between allergy and cancer should be explored further in prospective studies that any association identified between these conditions has the potential for significant public health implications.

Gut microbiota maturation during early human life induces enterocyte proliferation via microbial metabolites.

BACKGROUND: The intestinal tract undergoes a period of cellular maturation during early life, primarily characterized by the organization of epithelial cells into specialized crypt and villus structures. These processes are in part mediated by the acquisition of microbes. Infants delivered at term typically harbor a stable, low diversity microbiota characterized by an overrepresentation of various Bacilli spp., while pre-term infants are colonized by an assortment of bacteria during the first several weeks after delivery. However, the functional effects of these changes on intestinal epithelium homeostasis and maturation remain unclear. To study these effects, human neonate feces were obtained from term and pre-term infants. Fecal 16S rDNA sequencing and global untargeted LC-MS were performed to characterize microbial composition and metabolites from each population. Murine enteral organoids (enteroids) were cultured with 0.22 µm filtered stool supernatant pooled from term or pre-term infants. RESULTS: Term and pre-term microbial communities differed significantly from each other by principle components analysis (PCoA, PERMANOVA p < 0.001), with the pre-term microbiome characterized by increased OTU diversity (Wilcox test p < 0.01). Term communities were less diverse and dominated by Bacilli (81.54%). Pre-term stools had an increased abundance of vitamins, amino acid derivatives and unconjugated bile acids. Pathway analysis revealed a significant increase in multiple metabolic pathways in pre-term samples mapped to E. coli using the KEGG database related to the fermentation of various amino acids and vitamin biosynthesis. Enteroids cultured with supernatant from pre-term stools proliferated at a higher rate than those cultured with supernatant from term stools (cell viability: 207% vs. 147.7%, p < 0.01), grew larger (area: 81,189µm2 vs. 41,777µm2, p < 0.001), and bud at a higher rate (6.5 vs. 4, p < 0.01). Additionally, genes involved in stem cell proliferation were upregulated in pre-term stool treated enteroid cultures (Lgr5, Ephb2, Ascl2 Sox9) but not term stool treated enteroids. CONCLUSIONS: Our findings indicate that microbial metabolites from the more diverse gut microbiome associated with pre-term infants facilitate stem cell proliferation. Therefore, perturbations of the pre-term microbiota may impair intestinal homeostasis.

Protein Phosphatase 1 Down Regulates ZYG-1 Levels to Limit Centriole Duplication.

In humans perturbations of centriole number are associated with tumorigenesis and microcephaly, therefore appropriate regulation of centriole duplication is critical. The C. elegans homolog of Plk4, ZYG-1, is required for centriole duplication, but our understanding of how ZYG-1 levels are regulated remains incomplete. We have identified the two PP1 orthologs, GSP-1 and GSP-2, and their regulators I-2SZY-2 and SDS-22 as key regulators of ZYG-1 protein levels. We find that down-regulation of PP1 activity either directly, or by mutation of szy-2 or sds-22 can rescue the loss of centriole duplication associated with a zyg-1 hypomorphic allele. Suppression is achieved through an increase in ZYG-1 levels, and our data indicate that PP1 normally regulates ZYG-1 through a post-translational mechanism. While moderate inhibition of PP1 activity can restore centriole duplication to a zyg-1 mutant, strong inhibition of PP1 in a wild-type background leads to centriole amplification via the production of more than one daughter centriole. Our results thus define a new pathway that limits the number of daughter centrioles produced each cycle.

Sperm DNA fragmentation on the day of fertilization is not associated with embryologic or clinical outcomes after IVF/ICSI.

PURPOSE: To evaluate if sperm DNA fragmentation (SDF) in the sample used for intracytoplasmic sperm injection (ICSI) impacts outcomes after euploid blastocyst transfer. METHODS: Prospective cohort study of couples undergoing IVF with preimplantation genetic testing for aneuploidy from December 2014-June 2017. Sperm collected on the day of ICSI was analyzed for SDF using the sperm chromatin structure assay (SCSA®). Semen analysis parameters, embryologic outcomes, and clinical outcomes after euploid blastocyst transfer were compared between groups with DNA fragmentation index (DFI) ≤ 15% and DFI > 15% using Mann-Whitney U, t tests, and generalized linear mixed effects models. RESULTS: Two hundred thirty-four patients were included. One hundred seventy-nine men had DFI ≤ 15% (low DFI group) and 55 men had DFI > 15% group (high DFI group). Total motile sperm and sperm concentration were significantly lower in the group with DFI > 15% vs. DFI ≤ 15%. There was no difference in fertilization (86.3 vs. 84.2%, adjusted OR (95% CI) 0.86 (0.63-1.18)), blastulation (49.5 vs. 48.8%, adjusted OR 1.02 (0.75-1.36)), or euploidy (55.7 vs. 52.1%, adjusted OR 0.96 (0.7-1.31)) between the low and high DFI groups, respectively. Clinical outcomes were similar between low and high DFI groups, including implantation rate (68.8 vs. 79.8%), ongoing pregnancy rate (65.9 vs. 72.6%), and miscarriage rate (4.2 vs. 8.8%), respectively. CONCLUSION: Sperm DNA fragmentation on the day of ICSI is not associated with embryologic or clinical outcomes after euploid blastocyst transfer. Increasing levels of SDF are associated with low sperm concentration and total motile sperm count.

Campylobacter jejuni promotes colorectal tumorigenesis through the action of cytolethal distending toxin.

OBJECTIVE: Campylobacter jejuni produces a genotoxin, cytolethal distending toxin (CDT), which has DNAse activity and causes DNA double-strand breaks. Although C. jejuni infection has been shown to promote intestinal inflammation, the impact of this bacterium on carcinogenesis has never been examined. DESIGN: Germ-free (GF) ApcMin/+ mice, fed with 1% dextran sulfate sodium, were used to test tumorigenesis potential of CDT-producing C. jejuni. Cells and enteroids were exposed to bacterial lysates to determine DNA damage capacity via γH2AX immunofluorescence, comet assay and cell cycle assay. To examine the interplay of CDT-producing C. jejuni, gut microbiome and host in tumorigenesis, colonic RNA-sequencing and faecal 16S rDNA sequencing were performed. Rapamycin was administrated to investigate the prevention of CDT-producing C. jejuni-induced tumorigenesis. RESULTS: GF ApcMin/+ mice colonised with human clinical isolate C. jejuni81-176 developed significantly more and larger tumours when compared with uninfected mice. C. jejuni with a mutated cdtB subunit, mutcdtB, attenuated C. jejuni-induced tumorigenesis in vivo and decreased DNA damage response in cells and enteroids. C. jejuni infection induced expression of hundreds of colonic genes, with 22 genes dependent on the presence of cdtB. The C. jejuni-infected group had a significantly different microbial gene expression profile compared with the mutcdtB group as shown by metatranscriptomic data, and different microbial communities as measured by 16S rDNA sequencing. Finally, rapamycin could diminish the tumorigenic capability of C. jejuni. CONCLUSION: Human clinical isolate C. jejuni 81-176 promotes colorectal cancer and induces changes in microbial composition and transcriptomic responses, a process dependent on CDT production.

Mitochondrial replacement therapy.

PURPOSE OF REVIEW: The present study briefly reviews the history of mitochondrial replacement therapy (MRT); however, the focus is on recent advancements and future directions of the field. Specifically addressing societal and legal concerns and advances in MRT. RECENT FINDINGS: There continue to be new ethical debates surrounding MRT. In addition, there have been advancements in MRT techniques which could improve potential outcomes. Furthermore, advances in genetics continue to provide alternative approaches to treatment of many diseases, including alternatives to MRT. SUMMARY: MRT may be beneficial to eradicate a severely debilitating and often fatal disease. Despite significant supporting safety and efficacy, there are still many social and legal barriers to instituting MRT to clinical practice.

Do metacognitive judgments alter memory performance beyond the benefits of retrieval practice? A comment on and replication attempt of Dougherty, Scheck, Nelson, and Narens (2005).

A central question in the metacognitive literature concerns whether the act of making a metacognitive judgment alters one's memory for the information about which the judgment was made. Dougherty, Scheck, Nelson, and Narens (2005, Memory & Cognition, 33(6), 1096-1115) attempted to address this question by having participants make either retrospective confidence judgments (RCJs; i.e., evaluations of past retrieval success), judgments of learning (JOLs; i.e., predictions of future retrieval success), or no explicit judgments. When comparing final retrieval accuracy they found that accuracy was greater for items where participants had made JOLs compared with items that received RCJs or no judgment, suggesting that simply making a JOL can improve later memory performance. The present article presents results from four separate replication attempts that fail to duplicate this finding. Combined results provide compelling evidence that making a metacognitive judgment, regardless of the type, has no impact on later memory performance above and beyond retrieval practice.

Making Retrospective Confidence Judgments Improves Learners' Ability to Decide What Not to Study.

Predictions about future retrieval success, known as judgments of learning (JOLs), are often viewed as important for effective control over learning. However, much less is known about how retrospective confidence judgments (RCJs), evaluations of past retrieval success, may affect control over learning. We compared participants' ability to identify items that would benefit from additional study after making either a JOL or an RCJ. Participants completed a cued-recall task in which they made a metacognitive judgment after an initial recall attempt and before making a restudy decision. Participants who made RCJs prior to their restudy decisions were more accurate at identifying items in need of being restudied, relative to participants who made JOLs. The results indicate that having participants assess their confidence in past retrieval success can nudge them toward better utilizing of valid information when deciding which items are in need of further study.

Esophageal dilation with either bougie or balloon technique as a treatment for eosinophilic esophagitis: a systematic review and meta-analysis.

BACKGROUND AND AIMS: Esophageal dilation is a now recognized to be an important therapeutic modality in eosinophilic esophagitis (EoE). We aimed to evaluate the safety of esophageal dilation in EoE, especially regarding perforation risk, and to examine perforation risk by dilator type. METHODS: We conducted a systematic review of the published literature from January 1, 1950 to June 30, 2016 using PubMed, EMBASE, and Web of Science. Studies were included if they described patients with EoE who underwent elective esophageal dilation and also reported the presence or absence of at least 1 adverse event (eg, perforation, bleeding, pain, or hospitalization). We used random-effects meta-analysis to estimate the frequency of each adverse event. RESULTS: Of 923 identified articles, 37 met inclusion criteria and represented 2034 dilations in 977 patients. On meta-analysis, postprocedure hospitalization occurred in .689% of dilations (95% confidence interval [CI], 0%-1.42%), clinically significant GI hemorrhage in .028% (95% CI, 0%-.217%), and clinically significant chest pain in 3.64% (95% CI, 1.73%-5.55%). Nine perforations were documented, at a rate of .033% (95% CI, 0%-.226%) per procedure after meta-analysis. None of the perforations resulted in surgical intervention or mortality. Most (5/9) were reported before 2009 (rate, .41% [95% CI, 0%-2.75%]); from 2009 forward the rate was .030% (95% CI, 0%-.225%). Dilation method was described in 30 studies (1957 dilations), in which 4 perforations were detected. The estimated perforation rate for bougies was .022% (95% CI, 0%-.347%) and for balloons was .059% (95% CI, 0%-.374%). CONCLUSIONS: Perforation from esophageal dilation in EoE is rare, and there is no evidence of a significant difference in perforation risk related to dilator type. Esophageal dilation should be considered a safe procedure in EoE.

Evidence that exposure to progesterone alone is a sufficient stimulus to cause a precipitous rise in the immunomodulatory protein the progesterone induced blocking factor (PIBF).

PURPOSE: To determine if exposure to progesterone alone is sufficient to increase the production of the immunomodulatory protein known as the progesterone induced blocking factor (PIBF). Also to determine what method of progesterone delivery or form of P best stimulates PIBF secretion. METHODS: Serum samples from patients with infertility and paid volunteers were evaluated for both PIBF and progesterone at various times during the follicular phase and the luteal phase in both natural cycles and cycles involving embryo transfer after endogenous and exogenous progesterone exposure and after various synthetic progestins. PIBF was measured by a non-commercial research ELISA assay. Comparisons were made of serum PIBF before and after exposure to progesterone, 17-hydroxyprogesterone, and oral contraceptives. PIBF was also measured before and after transfer of embryos. RESULTS: Progesterone alone without exposure to the fetal allogeneic stimulus was able to produce a marked increase in serum PIBF. Neither a synthetic progestin (19-nortestosterone derivative) nor 17-hydroxyprogesterone caused an increase in PIBF. Some PIBF is generally detected even in the follicular phase. CONCLUSIONS: A previous concept considered that an allogeneic stimulus, e.g., from the fetal semi-allograft, was necessary to induce de novo progesterone receptors in gamma delta T cells, which, in turn, when exposed to a high concentration of progesterone, would secrete high levels of PIBF. These data show that exposure to an allogeneic stimulus is not needed to cause a marked rise in PIBF, merely progesterone alone is sufficient.