The hematopoietic microenvironment is composed of heterogeneous mesenchymal cells, such as osteoblasts, epithelial cells, fibroblastoid cells, adipocytes and macrophages, which are referred to as stromal cells. Stromal cells regulate hematopoietic stem cell (HSC) by producing positive- and negative-regulators to supply mature hematopoietic cells for the lifetime. It is well known that B lymphopoiesis in the bone marrow (BM) is attenuated with aging, whereas myelopoiesis is not affected. One standing issue is whether age-associated defects in B lymphopoiesis reflect intrinsic defects and/or extrinsic defects of the cells, such as stromal cell defects. Although extensive studies have revealed that age-associated intrinsic defects occur in B cell development, the age-associated stromal cell defects have not been fully elucidated. Since B lymphopoiesis in the BM is more dependent on stromal cells than the other lineages, B lymphopoiesis is a good model to investigate the effect of aging on stromal cells. Senescence accelerated mice (SAMP1) exhibit premature senescence-like stromal cell impairment after 30 weeks of age. Thus, this model mouse is a useful tool to clarify the role of stromal cells during the development of senescence-associated defects in B lymphopoiesis. In the steady state, SAMP1 mice exhibit simultaneous down-regulation of positive- and negative-regulators of B lymphopoiesis in the BM during premature aging, resulting in suppressive homeostasis of B cell development. While both regulators are down-regulated, the relative cytokine levels are barely maintained in the steady-state. Under perturbed conditions induced by 5-fluorouracil or irradiation, aged SAMP1 mice exhibit prolonged dysregulation of cytokine production, resulting in a further diminution of B lymphopoiesis. These results suggest that, in part, age-related deterioration of B cell development may be due to functional impairment of stromal cells, which induces vicious suppressive homeostasis of B cell development. Taken together, age-associated changes in hematopoiesis seem to be due not only to intrinsic-defects but also to extrinsic defects of hematopoietic cells.
Despite the evaluation of various improvised procedures, pancreatic leakage persists as a complication after pancreaticoduodenectomy (PD). Pancreaticoenteric reconstruction after PD is mainly achieved with either pancreaticojejunostomy (PJ) or pancreaticogastrostomy (PG), and many surgical centers adopt PG because anastomotic leakage is generally observed less frequently after PG than after PJ. However, pancreaticodigestive anastomotic stricture sometimes develops after PD with PG. Patency of the pancreaticoenterostomy is one of the most important factors affecting the function of the remnant pancreas and quality of life. Anastomotic stenosis after PG is attributed to acute inflammation and fibrosis around the anastomosis. We agree that duct-to-mucosa anastomosis is preferable in PG; however, it is not always easy to perform duct-to-mucosa anastomosis in the case of soft pancreas when the diameter of the pancreatic duct is small. Therefore, we use implantation of pancreatic stents in PG for soft pancreas with a small diameter pancreatic duct. On the other hand, pylorus-preserving pancreaticoduodenectomy (PPPD) reduces the incidence of post-gastrectomy syndrome (postprandial dumping, diarrhea, dyspepsia, nausea, and vomiting) following standard PD and yields better functional results. However, delayed gastric emptying (DGE) is one of the most troublesome complications of this procedure, which impairs patient recovery and prolongs the hospital stay after the surgery. Therefore, we developed a new technique, namely, “vertical stomach reconstruction with PG after Oida‘s modified subtotal stomach-preserving pancre-aticoduodenectomy (SSPPD)” to prevent DGE and were able to reduce the incidence of DGE. We review the relationship of DGE and pancreatic duct patency following PD with PG and present our SSPPD.
Few studies have been published about faculty medical education seminars and workshops. We retrospectively analyzed 62 workshops and 14 seminars held at Nihon University School of Medicine between 1985 and 2010. During the 26 year period, we had over 1531 participants. The topics, such as problem-based learning methodology, curriculum planning, and multiple-choice question development reflect the current medical education trends in Japan during that period.
Total hysterectomy is performed to treat hypermenorrhea and fibroids accompanied by dysmenorrhea, and is widely performed as an obstetrics and gynecology operation. In our department, total hysterectomy has been performed using an open incision in the abdomen to date. Due to recent advances in endoscopic surgery and operating equipment, the same operation can now be performed under laparoscopy. Herein, we report our establishment of the safe performance of total hysterectomy using a laparoscope combined with a cystoscope.
A 32-year-old man underwent thoracoscopic surgery for recurrent right pneumothorax. During the surgery, a 2 cm bleb with air leakage was confirmed in the pulmonary apex, he underwent a bullectomy with an endostapler. However, the air leak from the chest tube continued after the surgery and he immediately underwent a second thoracoscopy. Fossula of the anterior segment (S3) interlobar surface with air leakage was identified by water seal examination, and resection of this part successfully stopped the leakage. We considered that bulla of the pulmonary apex was the cause of the pneumothorax, and the lesion of S3 might be a perforation due to an external perioperative factor. During thoracoscopic surgery, excess overinflation should be avoided, as well as pulmonary injury by the ports because of the limited field of vision.
The patient in this report was a 38-year-old, female. She was admitted to our hospital with the complaint of fecal discharge from the vagina. We diagnosed her as having a rectovaginal fistula and operated on her performing a diverting colostomy in the sigmoid colon. We observed her for six months but the fistula continued to remain. Therefore, we con-sidered that successful treatment would require excision of the fistula and the transposition of healthy tissue between the rectum and vagina. Actually we used a gracilis muscle flap. If the gracilis muscle is cut, there is no influence of functional disorder. Since the second operation, the rectovaginal fistula has not recurred over the long term. We believe that the gracilis muscle is useful and effective for rectovaginal fistula.