XIdax, an inhibitor of the canonical Wnt pathway, is required for anterior neural structure formation in Xenopus.

Wnt signaling pathways are involved during various stages in the development of many species. In Xenopus, the accumulation of beta-catenin on the dorsal side of embryo is required for induction of the organizer, while the head structure formation requires inhibition of Wnt signaling. Here, we report a role for xIdax, a negative regulator of Wnt signaling. XIdax is expressed in neural tissues at the neurula stage, and in the restricted region of the tadpole brain. Ectopic expression of xIdax inhibits the target gene expression, suggesting that xIdax can inhibit canonical Wnt signaling. To examine the function of xIdax, a morpholino oligo for xIdax (xIdaxMO) was designed. An injection into an animal pole cell caused a loss of forebrain. The anterior neural marker expression is decreased in xIdaxMO-injected embryo, suggesting that xIdax is required for anterior neural development. Moreover, a negative regulator that acts downstream of xIdax rescued this defect. We propose that Idax functions are dependent on the canonical Wnt pathway and are crucial for the anterior neural development.     

Changes in the somatosensory N250 and P300 by the variation of reaction time

We investigated the relationship between somatosensory event-related potentials (ERP) and the variation of reaction time (RT). For this purpose, we recorded the ERPs (N250 and P300) in fast- and slow-reaction trials during a somatosensory discrimination task. Strong, standard, and weak target electrical stimuli were randomly delivered to the left median nerve at the wrist with a random interstimulus interval (900–1,100 ms). All the subjects were instructed to respond by pressing a button with their right thumb as fast as possible whenever a target stimulus was presented. We divided all the trials into fast- and slow-RT trials and averaged the data. N250 latency tended to be delayed when the RT was slow, but not significantly. P300 latency was delayed significantly when the RT was slow, but to a much lesser extent than the RT delay, so we concluded that the change of RT was not fully determined by the processes reflected by the somatosensory N250 or P300. Furthermore, the larger and earlier P300 in the fast-RT trials implied that when larger amounts of attentional resources were allocated to a given task, the speed of stimulus evaluation somewhat increased and RT was shortened to a great extent. N250 amplitude did not significantly vary in the two RT clusters. In conclusion, the somatosensory N250 reflects active target detection, which is relatively independent of the modulation of the response speed, whereas the somatosensory P300 could change without manipulation of either the stimulus or the response processing demand. Electronic Publication     

Immunohistochemical expressions of cytokeratins, mucin core proteins, p53, and neuroendocrine cell markers in epithelial neoplasm of appendix

Epithelial neoplasms of appendix are infrequent, and their pathological features are not fully characterized. We collected 33 cases of appendiceal tumors and examined immunohistochemically the expression of cytokeratins (CK, CK7, and CK20), mucin core protein (MUC1, MUC2, MUC5AC, and MUC6), E-cadherin, chromogranin A, and p53 protein. Gene analysis of TP53 was also conducted on exons 5 to 8. Clinically, mucinous tumors were predominant in females. Immunohistochemically, all the tumors expressed CK20, whereas CK7 was positive in one third of the cases. Similarly, MUC2 was expressed in all the tumors, whereas MUC1 and MUC5AC were detected in about a half of the cases. Although chromogranin A-positive cells are generally sparse in normal appendix, they were more common in mucinous tumors than in nonmucinous tumors. Contrary to the previous data reported (Mod Pathol 2002;15:599-605), mucinous carcinoma exhibited a higher frequency of p53-positive cells (mean 29%) compared with mucinous adenoma (2.8%) (P < .001), whereas nonmucinous tumors showed high levels of p53-positive cells to similar extent (51%-67%) in both adenoma and carcinoma. The high expression of p53 protein coincided with the presence of mutations in multiple sites of TP53 gene in mucinous tumors. This is the first report that characterized the immunophenotypic profile of appendiceal epithelial neoplasms with an emphasis of a higher frequency of p53 positivity in mucinous carcinoma cases compared with mucinous adenoma in the appendix.     

Osteoclast-type giant cell tumor of the endometrium. An immunohistochemical study

We present a rare case of a 55 year old female with an osteoclast-type giant cell tumor of the endometrium associated with leiomyoma and adenomyosis. Multinucleated giant cells and mononuclear stromal cells reacted with vimentin and alpha-1-antichymotrypsin (AACT) using the immunoperoxidase method. Epithelial membrane antigen (EMA), carcinoembryonic antigen (CEA), and keratin exhibited negative immunoreaction in these tumor cells. Our immunohistochemical results do not support the epithelial origin of an osteoclast-type giant cell tumor and mesenchymal derivation appeared more likely, suggesting histiocytic origin.     

CXCR4-transgene expression significantly improves marrow engraftment of cultured hematopoietic stem cells

Hematopoietic stem cells (HSCs) lose marrow reconstitution potential during ex vivo culture. HSC migration to stromal cell-derived factor (SDF)-1 (CXCL12) correlates with CXC chemokine receptor 4 (CXCR4) expression and marrow engraftment. We demonstrate that mobilized human CD34+ peripheral blood stem cells (CD34+ PBSCs) lose CXCR4 expression during prolonged culture. We transduced CD34+ PBSCs with retrovirus vector encoding human CXCR4 and achieved 18-fold more CXCR4 expression in over 87% of CD34+ cells. CXCR4-transduced cells yielded increased calcium flux and up to a 10-fold increase in migration to SDF-1. Six-day cultured CXCR4-transduced cells demonstrated significant engraftment in nonobese diabetic/severe combined immunodeficient mice under conditions in which control transduced cells resulted in low or no engraftment. We conclude that transduction-mediated overexpression of CXCR4 significantly improves marrow engraftment of cultured PBSCs.     

State of HBV DNA in HBsAg-negative, anti-HCV-positive hepatocellular carcinoma: existence of HBV DNA possibly as nonintegrated form with analysis by Alu-HBV DNA PCR and conventional HBV PCR

The role of hepatitis B virus (HBV) in carcinogenesis of hepatitis B surface antigen (HBsAg)-negative, anti-hepatitis C virus (anti-HCV)-positive hepatocellular carcinoma (HCC) remains unknown. To investigate the state of HBV DNA in such HCC, HBV DNA was examined by polymerase chain reaction (PCR) between HBV DNA and human Alu sequence (HBV-Alu PCR), which could detect integrated form of HBV DNA only, and by conventional HBV PCR, which could detect both integrated and episomal forms of HBV DNA. In all the 17 HBsAg-positive HCC, HBV DNA was detected by both HBV-Alu PCR method and conventional HBV PCR method. By contrast, in HBsAg-negative, anti-HCV-positive cases, HBV DNA was detected in 10 of 21 (47.6%) by conventional HBV PCR and in none of 21 (0%) by HBV-Alu PCR method. Thus, integrated form of HBV DNA was not found in most HbsAg-negative, anti-HCV-positive HCC in the current study. The role of episomal form of HBV DNA requires further investigation of its involvement in the process of the development of HBsAg-negative, anti-HCV-positive HCC.     

Therapy with nebulized beta2 agonists (procaterol) in asthmatic children: pulmonary function and plasma levels after inhalation]

BACKGROUND: Relationship between post administrative changes in plasma drug levels and bronchodilation remains unknown. In this study, we measured plasma levels of procaterol, a beta2-agonist, when being inhaled through nebulizers in children with bronchial asthma to examine relationship between improvement of pulmonary function and the plasma levels. METHOD: Six asthmatic children with the mean age of 9.8 years, inhaled 0.3 ml of 0.01% procaterol solution through a nebulizer. We examined changes in pulmonary function and plasma procaterol levels before and after inhalation. RESULTS: Procaterol was detected in the plasma 2 minutes after inhalation when it already rose to the maximum level, and kept the steady until showing a decline in 30 minutes. The measured highest value was 87.8+/-45.1 pg/ml. FEV 1.0 remarkably increased 2 minutes after inhalation and was maintained until 60 minutes after inhalation. Other lung function parameters also improved. There was no significant change in the heart rate, but serum potassium concentrations significantly dropped in all patients 60 minutes after inhalation. CONCLUSION: Plasma procaterol levels promptly rose to the peak at 2 minutes after inhalation and decreased 30 minutes later. Improvement of pulmonary function started promptly at minutes after inhalation and it became a peak 60 minutes later.     

Gain-of-function polymorphism in mouse and human Ltk: implications for the pathogenesis of systemic lupus erythematosus

Systemic lupus erythematosus (SLE), a complex multigenic disease, is a typical antibody-mediated autoimmune disease characterized by production of autoantibodies against a variety of autoantigens and immune complex-type tissue inflammation, most prominently in the kidney. Evidence suggests that genetic factors predisposing to aberrant proliferation/maturation of self-reactive B cells initiate and propagate the disease. In SLE-prone New Zealand Black (NZB) mice and their F1 cross with New Zealand White (NZW) mice, B cell abnormalities can be ascribed mainly to self-reactive CD5+ B1 cells. Our genome-wide scans to search for susceptibility genes for aberrant activation of B1 cells in these mice showed evidence that the gene, Ltk, encoding leukocyte tyrosine kinase (LTK), is a possible candidate. LTK is a receptor-type protein tyrosine kinase, belonging to the insulin receptor superfamily, and is mainly expressed in B lymphocyte precursors and neuronal tissues. Sequence and functional analyses of the gene revealed that NZB has a gain-of-function polymorphism in the LTK kinase domain near YXXM, a binding motif of the p85 subunit of phosphatidylinositol 3-kinase (PI3K). SLE patients also had this type of Ltk polymorphism with a significantly higher frequency compared with the healthy controls. Our findings suggest that these polymorphic LTKs cause up-regulation of the PI3K pathway and possibly form one genetic component of susceptibility to abnormal proliferation of self-reactive B cells in SLE.