Intestinal homeostasis is maintained by strict regulation of stem cell function. In mammals, several signaling pathways, including the formation of stem cell niches, are involved in stem cell regulation. However, little is known of the molecular mechanisms involved in postembryonic maturation of the vertebrate intestine, that is, the acquisition of cell renewal systems, including stem cell development and niche formation. Using thyroid hormone (TH) -dependent intestinal remodeling during amphibian metamorphosis as a model to study these mechanisms, we found that several signaling pathways, including the SHH/BMP4, WNT, Notch, and Hippo pathways, are regulated by TH and involved in stem cell regulation. In this review, we highlight findings regarding the role of these signaling pathways and discuss potential future avenues of study.

Background: Although pediatric immunoglobulin A nephropathy (IgAN) is considered to have a good prognosis, few studies have investigated histological changes over time in IgAN. Serial renal biopsies were performed during the course of the disease and histological changes were observed in patients who did not receive immunosuppressive treatment. To our knowledge, this is the first report of two or more histological evaluations of renal biopsies from patients with pediatric IgAN who did not receive immunosuppressive drugs. Methods: Forty-two patients with biopsy-proven IgAN who did not receive immunosuppressive agents and underwent serial renal biopsies were followed in our hospital between 1990 and 2003. This retrospective study evaluated findings from renal biopsy specimens and medical records. Results: Analysis of histological findings showed that 19 of 42 patients improved and 16 showed exacerbation of mesangial proliferation. Seven patients showed no obvious histological changes. Of the improved cases, 11 showed spreading of chronic lesions, and there was a significant difference between patients with and without segmental glomerular sclerosis or adhesion at the first biopsy. Of the exacerbated cases, only 5 of 16 patients showed strong active lesions at the first renal biopsy. Conclusions: Histological changes were investigated in pediatric IgAN patients not receiving immunosuppressive treatment. The results suggest that, even if mesangial hypercellularity improves, chronic lesions may spread during the natural history of the disease. Predicting histological changes by using findings from renal biopsies performed early after onset is difficult; therefore, patients should be carefully followed.

Background: Dentin matrix protein 1 (DMP1) is central to matrix mineralization. Clarification of the function of DMP1 is crucial to understanding normal bone formation and pathological calcification. The tissue-nonspecific alkaline phosphatase (TNAP) -progressive ankylosing enzyme (ANK) -extracellular nucleotide pyrophosphatase/phosphodiesterase-1 (ENPP1) axis induces deposition of hydroxyapatite (HA) and pyrophosphate dehydrate (CPPD) by regulating pyrophosphate (PPi). Here, we investigated the mechanism by which DMP1 and the TNAP-ANK-ENPP1 axis participate in mineralization. Methods: Expression of DMP1, TNAP, NPP1, and ANK genes in MC3T3-E1 cells was detected by RT-qPCR before and after treatment with DMP1 siRNA. An enzyme-linked immunosorbent assay was used to determine expression of DMP1 protein, TNAP activity was detected by SIGMAFAST p-nitrophenyl phosphate tablets, and mineralization of osteoblasts was determined by alizarin red staining. PPi levels were determined radiometrically and equalized for cell DNA. Levels of calcium, inorganic phosphate, zinc, and magnesium were assessed by standard laboratory techniques. Results: After DMP1 gene silencing, expressions of TNAP, ENPP1, and ANK were correspondingly reduced. DMP1 altered extravesicular and intravesicular ion levels through the TNAP-ENPP1-ANK axis in MC3T3-E1 cells. Conclusions: DMP1 regulated mineralization of MC3T3-E1 cells via the TNAP-ANK-ENPP1 axis and affected TNAP activity by two processes-rapid regulation of the Zn²⁺ transporter (ZnT) and transcriptional regulation of hysteresis. However, DMP1 may affect expression of ENPP1 and ANK only via hysteresis transcriptional regulation. DMP1, as a calcium trap or catalytic enzyme, appears to have a role in collagen mineralization.

Background: Residual shunt after closure of an inferior sinus venosus defect (ISVD) is a rare complication with a high rate of reintervention. Case Presentation: Here, we report a rare case of a recurrent defect identified 22 years after closure of an ISVD. The defect (25 × 10 mm) was located at the inferior vena cava-right atrial junction and was closed directly when the patient was 5 years of age. No residual shunt was detected and follow-up was discontinued at age 12 years. However, a residual atrial septal defect shunt was detected incidentally at age 27 years. During the second surgery, the lower end of the original defect was opened and then closed with an expanded polytetrafluoroethylene patch. Conclusions: Because of the high rate of reintervention for residual shunt after ISVD closure, patch closure was selected as a better option to reduce tension at the inferior-posterior border. Patients with this profile should be followed closely, at least during childhood, including by echocardiography.

A peritoneal loose body (PLB) is tissue completely separated from other intraperitoneal organs. It is rare and usually found incidentally during laparotomy, examination, or autopsy. PLBs are usually located free in the peritoneal cavity and not in the extraperitoneal space. They are thought to originate when epiploic appendices are released into the abdominal cavity after ischemic necrosis. We report a case of a giant PLB outside the peritoneal cavity, adjacent to the rectovesical excavation, that was identified preoperatively inan asymptomatic 83-year-old man undergoing evaluation for cholecystolithiasis. Computed tomography revealed a mass with well-defined margins in the rectovesical excavation. The mass (diameter, 60 mm) consisted of a calcified core and peripheral soft tissue and did not appear to invade adjacent organs. Although there were no symptoms or tumor growth over time, we scheduled a laparoscopic extraction for definitive diagnosis. On laparoscopic exploration, a white ovoid mass was found in the rectovesical excavation; there was no invasion of adjacent organs. We diagnosed a giant PLB. Postoperative recovery was uneventful. Most PLBs are asymptomatic and do not require surgery, except when symptoms are present, when the PLB is large, or when malignancy is suspected. PLB is rarely extraperitoneal and is usually freely mobile; however, in our patient, it was fixed and outside the abdominal cavity, near the rectovesical fossa. Although it could not be diagnosed preoperatively as being extraperitoneal, imaging findings were typical of PLB; thus, it was possible to remove the mass laparoscopically without bowel resection.

Bariatric surgery is performed worldwide to address morbid obesity. The benefits of this surgery are weight loss and a decrease in obesity-related complications. The relationship between metabolic/bariatric surgery and reemployment has been evaluated in Western countries, but few such studies have been performed in Japan because the number of metabolic/bariatric surgeries is small. Only a limited number of Japanese studies have evaluated the effects of bariatric surgery on obesity stigma, which affects employment and advancement opportunities for obese persons and may result in dismissal. We describe a case of bariatric surgery for a 39-year-old man who was dismissed from his job because of morbid obesity. Traditional weight loss methods failed to maintain weight loss and, preoperatively, the patient was receiving treatment for type 2 diabetes, hypertension, and abnormal lipid metabolism. He underwent sleeve gastrectomy and lost 50.4 kg (percent excess weight loss: 68.1%) in the first postoperative year. All medications were stopped after improvement in the results of laboratory blood tests and he was reemployed at 8 months after surgery. Increased social activity associated with employment is a factor in suppressing rebound weight gain after bariatric surgery, and weight loss associated with bariatric surgery helps decrease anti-obesity social stigma.

Many previous reviews of the literature have described the grafts and techniques for management of defects in the upper arm. However, the alternatives are limited in cases where some conventional flaps are not available and the nearby donor vessels have been previously sacrificed for free flaps. A 77-year-old man presented with a tumor in the right upper arm just above the axilla. The patient had already undergone surgeries for three recurrences of low-grade myxofibrosarcoma, the primary site of which was around the right scapula. The pectoralis major musculocutaneous flap was used for the defect caused by tumor resection, since there was no other available option. An acceptable result was obtained without any major complications. Thus, the pectoralis major myocutaneous flap may be a candidate for reconstruction of defects in the proximal part of the upper arm.

Supracondylar humerus fractures are the most common upper limb injury in children, but the incidence of flexion-type fractures is relatively low. Herein, we report the clinical results for three children with Gartland type II flexion-type supracondylar humeral fractures treated by closed reduction and percutaneous pinning. From April 2004 to March 2020, 102 children with supracondylar humeral fractures underwent surgery at our hospital and related institutions. Four had a flexion-type supracondylar humeral fracture (3.9%). Three patients (1 boy and 2 girls) with Gartland type II flexion-type supracondylar humeral fractures were followed for more than 12 months. The patients were treated by closed reduction and percutaneous pinning. Age was 7-13 years at the time of injury, and the duration of postoperative follow-up was 12-16 months. In one case, ulnar nerve paresis was observed as a preoperative complication. After performing closed reduction, percutaneous Kirschner wire cross-fixation was performed. Subsequently, long upper limb cast fixation was carried out for 4 weeks postoperatively. One patient developed preoperative nerve paralysis but recovered in approximately 3 months, without postoperative complications such as infection, nerve paralysis, or cubitus varus or valgus deformity. Flynn's criteria results were excellent for two patients and good for one patient. To maintain anatomical reduction of the fracture fragment, closed reduction using a traction table and percutaneous steel wire fixation are useful for treating flexion-type supracondylar humerus fractures in children with Gartland type II fractures.

Sciatic hernia is a rare type of pelvic floor hernia. The herniated tissue can include the ureter, small and large bowel, and ovary, among other tissues. Only a few cases of laparoscopic treatment for a sciatic hernia with small-bowel incarceration have been reported. We report our experience using a laparoscopic approach for treatment of sciatic hernia in an 83-year-old woman and review the literature on sciatic hernias. The patient was referred to our hospital complaining of constipation and abdominal bloating. Computed tomography (CT) scanning showed a right sciatic hernia containing the small bowel. Laparoscopic repair of the sciatic hernia was performed using a self-fixating mesh. The patient was discharged after an uneventful postoperative course and has not developed abdominal bloating or constipation postoperatively. In conclusion, a sciatic hernia was successfully repaired using a laparoscopic trans-preperitoneal approach and ProGrip Self-Fixating Mesh.