Summary The fungal pathogen Candida albicans can transition from budding to hyphal growth, which promotes biofilm formation and invasive growth into tissues. Stimulation of adenylyl cyclase to form cAMP induces hyphal morphogenesis. The failure of cells lacking adenylyl cyclase (cyr1Δ) to form hyphae has suggested that cAMP signaling is essential for hyphal growth. However, cyr1Δ mutants also grow slowly and have defects in morphogenesis, making it unclear whether hyphal inducers must stimulate cAMP, or if normal basal levels of cAMP are required to maintain cellular health needed for hyphal growth. Interestingly, supplementation of cyr1Δ cells with low levels of cAMP enabled them to form hyphae in response to the inducer N-acetylglucosamine (GlcNAc), suggesting that a basal level of cAMP is sufficient for stimulation. Furthermore, we isolated faster-growing cyr1Δ pseudorevertant strains that can be induced to form hyphae even though they lack cAMP. The pseudorevertant strains were not induced by CO2, consistent with reports that CO2 directly stimulates adenylyl cyclase. Mutational analysis showed that induction of hyphae in a pseudorevertant strain was independent of RAS1, but was dependent on the EFG1 transcription factor that acts downstream of protein kinase A. Thus, cAMP-independent signals contribute to the induction of hyphal responses.

Background Gastric antral vascular ectasia is an infrequent cause of gastrointestinal-related blood loss manifesting as iron-deficiency anemia or overt gastrointestinal bleeding, and is associated with increased healthcare burdens. Endoscopic therapy of gastric antral vascular ectasia most commonly involves endoscopic thermal therapy. Endoscopic band ligation has been studied as an alternative therapy with promising results in gastric antral vascular ectasia. Aims The primary aim was to compare the efficacy of endoscopic band ligation and endoscopic thermal therapy by argon plasma coagulation for the management of bleeding gastric antral vascular ectasia in terms of the mean post-procedural transfusion requirements and the mean hemoglobin level change. Secondary outcomes included a comparison of the number of sessions needed for cessation of bleeding, the change in transfusion requirements, and the adverse events rate. Methods PubMed, Medline, SCOPUS, Google Scholar, and the Cochrane Controlled Trials Register were reviewed. Randomized controlled clinical trials and retrospective studies comparing endoscopic band ligation and endoscopic thermal therapy in bleeding gastric antral vascular ectasia, with a follow-up period of at least 6 months, were included. Statistical analysis was done using Review Manager. Results Our search yielded 516 papers. After removing duplicates and studies not fitting the criteria of selection, five studies including 207 patients were selected for analysis. Over a follow-up period of at least 6 months, patients treated with endoscopic band ligation had significantly lower post-procedural transfusion requirements (MD −2.10; 95% confidence interval (−2.42 − −1.77)) and a significantly higher change in the mean hemoglobin with endoscopic band ligation vs endoscopic thermal therapy (MD 0.92; 95% confidence interval (0.39 − 1.45)). Endoscopic band ligation led to a fewer number of required sessions (MD −1.15; 95% confidence interval (−2.30 − −0.01)) and a more pronounced change in transfusion requirements (MD −3.26; 95% confidence interval (−4.84 − −1.68)). There was no difference in adverse events. Conclusion Results should be interpreted cautiously due to the limited literature concerning the management of gastric antral vascular ectasia. Compared to endoscopic thermal therapy, endoscopic band ligation for the management of bleeding gastric antral vascular ectasia led to significantly lower transfusion requirements, showed a trend toward more remarkable post-procedural hemoglobin elevation, and a fewer number of procedures. Endoscopic band ligation may improve outcomes and lead to decreased healthcare burden and costs.

Giardia lamblia (also referred to as Giardia intestinalis and Giardia duodenalis) is the most common intestinal parasite in the world, affecting approximately 200 million people annually. Symptoms of Giardia include foul-smelling diarrhea, abdominal cramping, bloating, gas, and nausea. Although usually self-limiting, Giardia can progress to dehydration, malnutrition, and failure to thrive, especially in immunocompromised individuals. Early diagnosis and treatment is imperative to prevent and control infection of Giardia. Infectious Disease Society of America diagnostic guidelines recommend obtaining stool studies to diagnose Giardia; when stool studies are negative but suspicion remains high, duodenal aspirate microscopy is the only alternative diagnostic strategy suggested. We report a patient diagnosed incidentally with Giardia from a duodenal biopsy specimen obtained during a workup for a gastrointestinal bleed. There are limited cases of Giardia diagnosed by duodenal biopsy reported in the literature. We review studies that suggest duodenal biopsy can be a very sensitive strategy for the diagnosis of Giardia.

Malignancies of the small intestine are rare. Signet-ring cell carcinoma (SRCC) is one of the rarest forms of adenocarcinoma that can arise in the small intestines. We present a case of a patient who originally presented with abdominal pain and radiographic findings suggestive of ileal congestion. The ileal biopsy specimens were nonspecific, and the patient began a trial of corticosteroid treatment for suspected Crohn’s disease. A repeat colonoscopy yielded biopsies that were positive for malignancy. The patient then underwent an exploratory laparotomy which led to the diagnosis of SRCC. Given their similar presentations and the extreme rarity of this unusual malignancy, it can be difficult to differentiate between new-onset Crohn’s disease and SRCC. A review of the literature was conducted to provide us with an improved understanding of previously documented cases of SRCC.

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