Keiichiro Tanaka

Tenascin-C regulates angiogenesis in tumor through the regulation of vascular endothelial growth factor expression

In order to verify whether tenascin‐C (TN‐C) is involved in angiogenesis as an extracellular signal molecule during tumorigenesis, cancerous cell transplantation experiments and coculture experiments were carried out, focusing on the regulation of vascular endothelial growth factor (VEGF). The A375 human melanoma cells introduced the GFP gene (A375‐GFP), implanted subcutaneously into BALB/cA nude (WT) and TN‐C knockout BALB/cA nude (TNKO) congenic mice. Furthermore, coculture experiments between A375‐GFP and embryonic mesenchyme, which was prepared from both genotypes, were carried out to investigate the molecular mechanism in the cell‐cell interactions. Both the content of TN‐C and that of VEGF in the tumor and the conditioned medium were analyzed by the sandwich ELISA method. Seven days after transplantation of the A375‐GFP, capillary nets became far more abundant in the tumors grown in WT mice than those in TNKO mice. Interestingly, VEGF and TN‐C expressions showed antithetical expression patterns between the tumors in WT mice and those in TNKO mice. This peculiar phenomenon seems to be caused by a time lag prior to the onset of the mesenchymal regulation for the TN‐C expression of A375‐GFP. The coculture experiments revealed that WT mesenchyme had a much stronger effect than TNKO mesenchyme on both TN‐C and VEGF expression. However, the defects of TNKO mesenchyme were restored in all cases by additional TN‐C. These results clearly indicated that the expressions of both TN‐C and VEGF depend on the surrounding mesenchyme, and that the function of mesenchyme is regulated by its own mesenchymal TN‐C. In conclusion, the present data suggest that the matrix microenvironment organized by the host mesenchyme is very important for angiogenesis in tumor development.

Lethal gastric rupture caused by acute gastric ulcer in a 6-year-old girl

Gastric rupture is extremely rare in childhood beyond the neonatal period. We describe a previously healthy 6-year-old girl with a large laceration along the greater curvature on the posterior wall of the stomach. The patient was admitted to a neighboring hospital because of vertigo with 1-day history of intractable vomiting and epigastric pain. Although abdominal distension was noticed during the physical examination, muscular rigidity was not detected on palpation. Laboratory data showed severe hypotonic dehydration and moderate metabolic acidosis with hyperkalemia. She suddenly developed cardiac arrest within an hour after admission. After resuscitation, surgical consultation was obtained. Abdominal X-ray and ultrasound revealed abdominal free air and massive cloudy ascites. At laparotomy, there was a large laceration on the greater curvature of the stomach. Pathology of the gastric wall showed mucosal necrosis while the musculature remained intact consistent with an acute gastric ulcer. Since clinical condition of gastric rupture deteriorates rapidly, early diagnosis and appropriate treatment is essential for good prognosis. One should consider that ulcer formation might cause gastric rupture in childhood.

Esophageal Replacement Using a Reversed Gastric Tube for Lye Stricture in a Child: Report of a Case

A 5-year-old girl ingested lye, a detergent used in electric dishwashers. She was transferred to our hospital after balloon dilatation, performed for stenosis resulting from corrosive esophagitis, was complicated by esophageal perforation causing mediastinitis. Although the mediastinitis resolved with conservative treatment, the stenosis did not improve. Therefore, we performed esophageal replacement using a reversed gastric tube, which successfully relieved the obstruction, although she still had slight gastroesophageal reflux 6 months postoperatively.

Enucleation of solid pseudopapillary tumor with a preoperative nasopancreatic drainage stent in a child

Solid pseudopapillary tumor (SPT) is a rare pancreatic tumor with low‐grade malignancy in children. A complete surgical resection can achieve a favorable prognosis. Although several reports have indicated that enucleation is considered a safe and effective treatment, the most significant complication is injury to the main pancreatic duct. The usefulness and safety of tumor enucleation after preoperative placement of an endoscopic nasopancreatic drainage stent (NPDS) has recently been reported. We present the case of SPT in a 10‐year‐old girl. To avoid and detect injury to the main pancreatic duct during operation, an NPDS was endoscopically placed before laparotomy. The patient underwent a complete enucleation of the tumor with the guidance of an NPDS. Our case is the first report of a successful enucleation of an SPT with a preoperative placement of an NPDS. This procedure may lead to safe enucleation of a pancreatic tumor with low malignancy, such as SPT, in children.

Clinicopathological Features of Thymoma with Ring Calcification: Case Reports

Thymomas with ring calcifications are very rare and quaint style. Herein, we presented our three cases of thymomas with ring calcifications and reviewed totally 10 cases including 7 cases of previous English literatures. The median age was 53 years. Myasthenia gravis was a complication in 40%. The median maximal diameter was 50 mm. They were diagnosed as pathological type B or had type B component. Based on World Health Organization (WHO) classification, 20%, 60%, and 20% cases were stage I, stage II, and stage III, respectively. Seven ring calcifications were within tumors (inner type) and two cases were outside tumors (outer type). The other had a thymoma arising in the calcic wall of a calcified thymic cyst (miscellaneous type). Four other anterior mediastinal tumors with ring calcification had been reported. We need pathological examinations for a definitive diagnosis. Surgeons should plan surgery because of the possibility of invasive thymomas, or other malignant tumors.

Lactate Levels in Bowel Strangulation With Experimental Animal Model

Bowel strangulation is a common disease and often requires an urgent operation. Our previous report showed that lactate concentration in the blood is a good predictive marker for emergency. However, the alteration in lactate levels during the course of bowel strangulation remains unclear. We have investigated the progressive increase of lactate after induction of bowel strangulation with animal experiments. Thirty-six mice were randomly divided into 6 groups: 0, 8, 16, 24, 48, and 72 hours after operation. Under anesthesia, laparotomy was performed and a 5-cm segment of terminal ileum with the mesenteric artery and veins was ligated to create a strangulation obstruction. After operation, the arterial blood was collected and lactate concentration and pH were measured using a blood gas analyzer. Lactate concentration in the 8-hour group was markedly increased, while pH decreased significantly (P < 0.05). Lactate concentrations were kept at a high level from 8 to 72 hours after operation. The time lag between strangulation and an increase of lactate is 8 hours. Our study is the first report of a bowel strangulation mouse model. Therefore, it would be possible to find a more specific marker of bowel strangulation using our experimental model.