Background The way by which 1-deamino-8-D-arginine vasopressin (DDAVP) acts on platelets remains unclear. Data from the literature tend to show that there is no definite effect on platelet activation, but recent work has suggested that a subtype of platelets, activated by the combined action of collagen and thrombin, was triggered by DDAVP. Moreover, platelet microparticles (PMPs), which have been shown to be procoagulant, have rarely been studied in this context. The goal of this study was to analyze the effects of DDAVP on PMPs' release through platelet activation. Methods Fifteen out of 18 consecutive patients undergoing a therapeutic test with DDAVP were included. They were suffering from factor VIII deficiency or from von Willebrand disease. The expression of P-selectin and PAC-1 binding on platelets and the numbers of circulating PMPs were evaluated ex vivo before and after DDAVP infusion. Peripheral blood was collected on CTAD to limit artifactual platelet activation. Results DDAVP induced a significant decrease of platelet counts and volume. Only small changes of P-selectin expression and PAC-1 binding were observed. Considering PMPs, two populations of patients could be defined, respectively, with (120%, n = 6) or without (21%, n = 7) an increase of PMPs after DDAVP. The decrease in platelet counts and volume remained significant in the group of responders. Conclusion This study shows that DDAVP induces the generation/release of PMPs in some patients with factor VIII deficiency and von Willebrand disease 1 hour after DDAVP infusion.

Question: An 86-year-old French man was admitted to the hospital with diarrhea, rectal bleeding, and anal pain during defecation. He subsequently underwent digestive endoscopic examinations. The patient was a sturdy old man and a former soldier who had traveled overseas extensively, >30 years before presentation. He had been treated, 2 years prior, for adrenal insufficiency and myasthenia gravis with pyridostigmine, immunoglobulin infusions, and immunosuppressive drugs (azathioprine, later replaced by mycophenolate mofetil).Clinical examination revealed 2 large perianal ulcerations (Figure A). Gastric fibroscopy was normal and colonoscopy showed a normal ileal mucosa and colorectal ulcerations with spacing of healthy mucous membrane. Biopsies of the colic and perianal ulcerations revealed a noncaseating epithelioid and giant cell granuloma, along with the presence of yeast, which led to a preliminary diagnosis of Crohn's disease (Figure B, C; stain: hematoxylin eosin Safran staining; original magnification Â40 and Â100, respectively). Before the introduction of anti-tumor necrosis factor-a, laboratory results for tuberculosis, HIV, as well as hepatitis B and C were confirmed as negative. The patient was treated with infliximab but showed no improvement after 3 doses and he developed a fever. He was then treated with several probabilistic antibiotic therapies.Laboratory results revealed a pancytopenia: white blood count, 2.2 Â 10 9 /L; hemoglobin, 9.1 g/dL; and platelets, 47 Â 10 9 /L. What is the diagnosis? Look on page 1702 for the answer and see the Gastroenterology web site (www.gastrojournal.org) for more information on submitting your favorite image to Clinical Challenges and Images in GI.

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An 82-year-old woman was admitted for cardiac insufficiency associated with obesity, renal insufficiency, and refractory atrial fibrillation. The patient had no history of hematological malignancies. Clinical examination revealed no lymphadenopathy, tumoral syndrome, or weight loss. Hematological tests showed the following: platelets, 173×10 9 /L; hemoglobin, 10.3 g/dL; white blood cells, 10.5×10 9 /L; and lymphocytes, 5.60×10 9 /L. Cytological examination of blood smear indicated the presence of small lymphocytes with very mature chromatin, regular nuclei, and multiple intracytoplasmic sharp vacuoles, accounting for 41% of the total lymphocytes, as determined by manual differential white blood cell count (Panel A-I, May-Grünwald Giemsa Staining; ×1,000). Flow cytometry analysis indicated the typical profile of chronic lymphocytic leukemia (CD5+, CD23+, FMC7-, CD22-, CD43+, and low monoclonal lambda chain). Due to the advanced age of the patient, cytogenetic analysis was not performed. Vacuoles are spherical organelles consisting of a double lipid layer; they contain intra or extracellular proteinaceous material. Vacuoles in lymphocytes have been reported in lysosomal storage diseases and neoplastic disorders; moreover, they are physiologically present in T and natural killer lymphocytes. Although vacuoles are more or less specific, they deserve attention as they can offer valuable insights.