SPA-1 (signal-induced proliferation-associated gene-1) is a principal Rap1 GTPase-activating protein in hematopoietic progenitors. SPA-1-deficient mice developed a spectrum of myeloid disorders that resembled human chronic myelogenous leukemia (CML) in chronic phase, CML in blast crisis, and myelodysplastic syndrome as well as anemia. Preleukemic SPA-1-deficient mice revealed selective expansion of marrow pluripotential hematopoietic progenitors, which showed abnormal Rap1GTP accumulation. Overexpression of an active form of Rap1 promoted the proliferation of normal hematopoietic progenitors, while SPA-1 overexpression markedly suppressed it. Furthermore, restoring SPA-1 gene in a SPA-1-deficient leukemic blast cell line resulted in the dissolution of Rap1GTP accumulation and concomitant loss of the leukemogenicity in vivo. These results unveiled a role of Rap1 in myeloproliferative stem cell disorders and a tumor suppressor function of SPA-1.

We previously reported that the mice deficient for SPA-1, a Rap1 GTPase-activating protein, developed hematopoietic stem cell disorders. Here, we demonstrate that SPA-1(-/-) mice show an age-dependent increase in B220(high) B1a cells producing anti-dsDNA antibody and lupus-like nephritis. SPA-1(-/-) peritoneal B1 cells revealed the altered Vkappa gene repertoire, including skewed Vkappa4 usage and the significant Igkappa/Iglambda isotype inclusion indicative of extensive receptor editing. Rap1GTP induced OcaB gene activation via p38MAPK-dependent Creb phosphorylation, and consistently, SPA-1(-/-) immature BM B cells showing high Rap1GTP exhibited the augmented expression of OcaB and Vkappa4 genes. SPA-1(-/-) BM cells could transfer the autoimmunity in association with the generation of peritoneal B220(high) B1a cells in Rag-2(-/-) recipients. Finally, a portion of SPA-1(-/-) mice developed B1 cell leukemia with hemolytic autoantibody. Present results suggest that the regulated Rap1 signal in the immature B cells plays a role in modifying the B cell receptor repertoire and in maintaining the self-tolerance.

Assisted reproductive technology is a widely accepted treatment for infertile women with endometriosis. The presence of an ovarian endometrial cyst reduces the quality of oocytes, while surgical resection of endometrioma may reduce the ovarian reserve for ovarian stimulation by exogenous gonadotropins. To determine what pretreatment should be performed for ovarian endometrial cyst before IVF-ET, we analyzed IVF outcomes with or without pretreatment in patients with endometrioma. Infertile women with endometrioma who underwent IVF-ET were divided into 3 groups, including patients who had received laparotomy or laparoscopy, patients for whom the endometrioma content had been aspirated and treated with or without alcohol fixation, and patients who did not undergo pretreatment. The number of retrieved oocytes, rate of mature oocytes, and fertilization rate were compared among groups. The results showed that pretreatment for endometrioma reduces the number of retrieved oocytes. Although oocyte quality as a rate of mature oocytes was not affected by the presence of an ovarian endometrial cyst, the fertilization rate was improved by cyst aspiration. We propose that surgical pretreatment is not necessary for ovarian endometrial cyst before IVF-ET, but cyst aspiration may be beneficial after several failed attempts of IVF.

According to a recent report by the Committee for Scientific Affairs of the Japanese Association for Thoracic Surgery, pulmonary metastasectomy accounted for as many as 10.2 % of all entry cases of general thoracic surgery, and its use is increasing year by year. Accordingly, many studies have examined the surgical procedures used during pulmonary metastasectomy for metastases from primary tumors affecting various organs as well as the outcomes of and indications for such procedures, but some problems remain. In this article, the following questions related to the surgical approach and the type of resection used during pulmonary metastasectomy are reviewed: (1) Wedge resection--what is a safe margin for preventing local recurrence? (2) What is the clinical significance of node sampling/dissection during pulmonary metastasectomy? and (3) When is segmentectomy necessary? In addition, we discuss: (4) open thoracotomy vs. video-assisted thoracoscopic surgery (VATS), (5) repeated metastasectomy for pulmonary metastases, (6) the surgical approach for bilateral pulmonary metastasectomy, (7) pneumonectomy, and (8) pulmonary metastasectomy combined with resection of the neighboring organs.

SPA-1 is a principal Rap1 GTPase-activating protein in the hematopoietic progenitors and peripheral T cells, and SPA-1-deficient mice develop a spectrum of myeloproliferative stem cell disorders of late onset. In the present study, we show that SPA-1-deficient mice develop age-dependent T cell unresponsiveness preceding the myeloid disorders, whereas the T cell numbers remained unchanged. Progression of the T cell dysfunction was attributed to the age-dependent increase in CD44 high T cell population that was unresponsive to T cell receptor stimulation. Younger SPA-1-deficient mice exhibited selectively impaired recall T cell responses against a T-dependent antigen with normal primary antibody response. These results suggested that the unresponsiveness of CD44 high T cells was antigen-driven in vivo. T cells from younger SPA-1 ؊/؊ mice showed much greater and more persisted Rap1 activation by anti-CD3 stimulation than control T cells. Furthermore, freshly isolated T cells from SPA-1 ؊/؊ mice exhibited progressive accumulation of Rap1GTP as mice aged. T cells from aged SPA-1 ؊/؊ mice with high amounts of Rap1GTP showed normal or even enhanced Ras activation with little extracellular signal-regulated kinase activation in response to anti-CD3 stimulation, indicating that excess Rap1GTP induced the uncoupling of Ras-mediated extracellular signal-regulated kinase activation. These results suggested that antigenic activation of naïve T cells in SPA-1 ؊/؊ mice was followed by anergic rather than memory state due to the defective down-regulation of Rap1 activation, resulting in the age-dependent progression of overall T cell immunodeficiency.