Role of Dok-1 and Dok-2 in myeloid homeostasis and suppression of leukemia

Dok-1 and Dok-2 are closely related rasGAP-associated docking proteins expressed preferentially in hematopoietic cells. Although they are phosphorylated upon activation of many protein tyrosine kinases (PTKs), including those coupled with cytokine receptors and oncogenic PTKs like Bcr-Abl, their physiological roles are largely unidentified. Here, we generated mice lacking Dok-1 and/or Dok-2, which included the double-deficient mice succumbed to myeloproliferative disease resembling human chronic myelogenous leukemia (CML) and chronic myelomonocytic leukemia. The double-deficient mice displayed medullary and extramedullary hyperplasia of granulocyte/macrophage progenitors with leukemic potential, and their myeloid cells showed hyperproliferation and hypo-apoptosis upon treatment and deprivation of cytokines, respectively. Consistently, the mutant myeloid cells showed enhanced Erk and Akt activation upon cytokine stimulation. Moreover, loss of Dok-1 and/or Dok-2 induced blastic transformation of chronic phase CML-like disease in mice carrying the bcr-abl gene, a cause of CML. These findings demonstrate that Dok-1 and Dok-2 are key negative regulators of cytokine responses and are essential for myeloid homeostasis and suppression of leukemia.     

Papillary dilation vs sphincterotomy in endoscopic removal of bile duct stones a randomized trial with manometric function

To circumvent the long-term effects of papillary ablation for extracting common bile duct stones (<12 mm in diameter) in endoscopic sphincterotomy (EST), endoscopic papillary dilation (EPD) was attempted in 20 patients. To evaluate papillary function before and after the procedures, manometry of the sphincter of Oddi was carried out in 13 with EPD and 10 of 20 patients with EST. Extraction of all stones was successful (100%) in both groups at an equal rate. Repeated numbers of procedures were common in both groups. However, the mean duration of the procedure was high in EPD compared to EST (63 min vs 42 min,P<NS). Adjunctive therapies like mechanical lithotripsy (ML), nasobiliary drainage, and choledochoscopy were included in EPD, while EST required a basket catheter and ML. There was no significant difference on manometry before and after the procedures (P=NS), although papillary function was found to have decreased after the EPD. In contrast, all patients in the EST group lost papillary function after the procedure. Thirty-day morbidity and mortality rate were absent in both groups. Immediate and 2.5-year follow up complications were uncommon in both groups. As a simple method, EPD may be an effective and safe alternative to EST in the management of patients with bile duct stones who require maintenance of papillary function.     

P wave changes on exercise in patients with isolated mitral stenosis

Patients with mitral stenosis usually showed a marked increase in the P negativity following exercise. The P terminal force in Lead V₁ in 20 cases with isolated mitral stenosis was ?0.090 mm. sec. before exercise, which changed to ?0.177 mm. sec. following the single Master two-step test.Normal adults never showed such changes on exercise. The phenomenon was considered to be due to the posterior rotation of the P wave vector in the horizontal plane, which was induced by the enlargement of the left atrial wall on exercise.     

SLIT Improves Cedar Pollinosis by Restoring IL-10 Production from Tr1 and Monocytes~IL-10 Productivity Is Critical for Becoming Allergic ~

BackgroundAllergen-specific immunotherapy (SIT) is currently used for several allergic disorders and IL-10- producing regulatory T cells (Tr1) induced by SIT suppress allergic reactions. We investigated the relation between IL-10 production and acquiring allergy.MethodsA prospective study was undertaken to evaluate the effect of SIT on IL-10 production in T cells and other cell fractions in children with pollinosis. In addition, blood samples were collected from non-allergic healthy controls and patients with pollinosis to compare the levels of IL-10 production. PBMC were cultured with pollen peptides or control allergens, and the IL-10 production from monocyte and CD4 T cell was analyzed.ResultsMonocytes and CD4 T cells from SIT group of patients produced high levels of IL-10, suggesting that the induction of IL-10 is essential for inducing T cell tolerance. IL-10 production from monocytes and T cells was significantly increased in non-allergic controls compared to patients with pollinosis. This high IL-10 production was observed even when PBMC were stimulated with antigens other than pollen peptides.ConclusionsIL-10 is critical for induction of specific T cell tolerance, and increased production of IL-10 by monocytes and T cells during inflammatory responses or after SIT may influence effector cells in allergy. Present data implicates that the low productivity of IL-10 by monocytes and T cells is closely related with sensitivity to multiple allergens, and resistance to allergic diseases. Augmentation of constitutive IL-10 production from immune system is a potential therapeutic approach for allergic disorders.     

Effect of stretch on improvement of muscular contractures in rats

[Purpose] The purpose of this study was to investigate how a stretching torque affects muscular contractures. [Subjects] The subjects of this study were 48 male Wistar rats. [Methods] Subjects were divided into 4 groups as follows: Group 1 was the control; Group 2 had muscles in continuous fixation; Group 3 had muscles stretched in the direction of dorsiflexion by a spring balancer set at a torque of 0.3N for a period of 30 minutes after continuous fixation; and Group 4 had muscles stretched in the direction of dorsiflexion by a spring balancer set at a torque of 3.0N for a period of 30 minutes after continuous fixation. Joint fixation periods were for 2 and 4-weeks. Ankle joint range of motion and soleus flexibility were analyzed. [Results] For the 2-week joint fixation, soleus flexibility in Group 4 showed an increase compared with that of Group 3. For both fixation periods, range of motion in Group 4 showed an increase compared with that of Group 3. [Conclusion] For both fixation periods, stretching improved joint range of motion. In the 2-week joint fixation, soleus flexibility improved. However, soleus flexibility did not improve in the 4-week joint fixation.Key words: Muscular contracture, Stretching, Muscular flexibility     

PU.1 as an essential activator for the expression of gp91phox gene in human peripheral neutrophils, monocytes, and B lymphocytes

We have reported a deficiency of a 91-kDa glycoprotein component of the phagocyte NADPH oxidase (gp91^phox) in neutrophils, monocytes, and B lymphocytes of a patient with X chromosome-linked chronic granulomatous disease. Sequence analysis of his gp91^phox gene revealed a single-base mutation (C → T) at position −53. Electrophoresis mobility-shift assays showed that both PU.1 and hematopoietic-associated factor 1 (HAF-1) bound to the inverted PU.1 consensus sequence centered at position −53 of the gp91^phox promoter, and the mutation at position −53 strongly inhibited the binding of both factors. It was also indicated that a mutation at position −50 strongly inhibited PU.1 binding but hardly inhibited HAF-1 binding, and a mutation at position −56 had an opposite binding specificity for these factors. In transient expression assay using HEL cells, which express PU.1 and HAF-1, the mutations at positions −53 and −50 significantly reduced the gp91^phox promoter activity; however, the mutation at position −56 did not affect the promoter activity. In transient cotransfection study, PU.1 dramatically activated the gp91^phox promoter in Jurkat T cells, which originally contained HAF-1 but not PU.1. In addition, the single-base mutation (C → T) at position −52 that was identified in a patient with chronic granulomatous disease inhibited the binding of PU.1 to the promoter. We therefore conclude that PU.1 is an essential activator for the expression of gp91^phox gene in human neutrophils, monocytes, and B lymphocytes.     

Interleukin 15 activity in the rectal mucosa of inflammatory bowel disease

Background & Aims: Interleukin (IL)-15 has been found to share many immunoregulatory activities in lymphocytes with IL-2. The aim of this study was to investigate IL-15 activity in organ cultures, localization of IL-15 messenger RNA (mRNA), and proliferation of lamina propria mononuclear cells (LPMCs) in response to recombinant IL-15 using the mucosal tissues obtained from patients with inflammatory bowel disease (IBD). Methods: The contents of IL-15, tumor necrosis factor α, and IL-2 in the culture supernatant of the rectal mucosal tissues were determined by an enzyme-linked immunosorbent assay. Expression of IL-15 mRNA was analyzed by in situ hybridization, and proliferative response of LPMCs to recombinant IL-15 was determined by [³H]thymidine incorporation into DNA. Results: Significantly greater IL-15 activity was detected in active IBD, and this elevation was also observed in inactive ulcerative colitis. In contrast, greater tumor necrosis factor α activity was observed only in active IBD, and IL-2 was not detected in organ cultures. In situ hybridization showed IL-15 mRNA in macrophages and epithelial cells in active IBD specimens, and recombinant IL-15 induced a dose-dependent proliferative response in LPMCs. Conclusions: Mucosal IL-15 may be involved in the pathogenesis of IBD as one of the important mediators in activation of mucosal immune cells.GASTROENTEROLOGY 1998;114:1237-1243