Takemasa Midorikawa

Novel NF1 gene mutation in a Japanese patient with neurofibromatosis type 1 and a gastrointestinal stromal tumor

Many mutations of the NF1 gene have been reported in patients with neurofibromatosis type 1 (NF1); however, there have been no documented NF1 gene mutations in Japanese NF1 patients. In the present study, we used the polymerase chain reaction (PCR) and DNA sequencing analysis to characterize the NF1 gene in a 53-year-old Japanese patient with NF1 who suffered from neurofibroma, pheochromocytoma, and gastrointestinal stromal tumor (GIST). Direct sequence analyses revealed a single base substitution in the splicing donor site of intron 6 (IVS6 888+1, G → A) in one NF1 allele, resulting in an altered splice site (ss) in the mutated allele. Splicing at the cryptic 5′ ss in the mutated allele generated mRNA with an insertion of 60 nucleotides. In addition, we screened for mutations in exons 9, 11, 13, and 17 of the c-kit gene in GIST and the succinate dehydrogenase subunit D (SDHD) gene in the pheochromocytoma, but we did not detect any somatic mutations. We report here the first case of an NF1 patient with four neoplasms: neurofibroma, pheochromocytoma, astrocytoma and GIST. Our results suggest that the molecular pathogenesis of GISTs in NF1 patients is different from that in non-NF1 patients.

Prevention of reactive oxygen-induced endothelial cell injury by blocking its process.

Endothelial cell (EC) injury induced by reactive oxygen species (ROS) was investigated and effects of Ca²⁺ channel blockers, agents which elevate intracellular cAMP levels ([cAMP]_i), and protein kinase inhibitors on H₂O₂-induced EC injury were analyzed using human umbilical vein EC cultures. Exposure to H₂O₂ increased intracellular Ca²⁺ levels and decreased [cAMP]_i. Ca²⁺ channel blockers, [cAMP]_i-elevating agents, and protein kinase inhibitors significantly inhibited H₂O₂-induced EC injury. Data suggest that H₂O₂-induced EC injury is mediated by extracellular Ca²⁺ influx, intracellular cAMP efflux, and intracellular signaling, each of which is blocked by Ca²⁺ channel blockers, [cAMP]_i-elevating agents, or protein kinase inhibitors. It is suggested that ischemia/reperfusion injury induced by ROS may be prevented by Ca²⁺ channel blockers, [cAMP]_i-elevating agents, and protein kinase inhibitors.

Liver function assessed by increased rate of Portal venous blood flow after oral intake of glucose

OBJECTIVE To find out whether an increased rate of portal venous blood flow after oral intake of glucose could be used to estimate liver function. DESIGN Prospective study. SETTING University hospital, Japan. SUBJECTS Sixty patients, of whom 23 had hepatocellular carcinoma and liver cirrhosis, 21 had tumours metastatic to normal liver, and 16 had obstructive jaundice treated with percutaneous transhepatic biliary drainage (PTBD). INTERVENTION Portal flow was measured after oral intake of glucose 75 g using pulsed-Doppler ultrasonography. RESULTS The ratio of portal flow 30 minutes after glucose intake to that before intake (PVFR30) was significantly lower in cirrhotic patients than in those with metastases and a normal liver. A PVFR30 of less than 1.5 indicated impaired hepatic function assessed by the Child-Pugh scores, indocyanine green clearance test, prothrombin time, and hepaplastin test. It also indicated less reduction in total bilirubin concentrations in the first week after PTBD. CONCLUSIONS Results suggest that PVFR30 can be used to estimate liver function and predict outcome after PTBD.

Allopurinol Reduced Hepatic Ischemia-Reperfusion Injury Exacerbated by Inhalation of High-Concentration Oxygen in Rats

Exposure to high-concentration oxygen (O2) increases lipid peroxidation of the cellular membrane, leading to tissue injury which may involve hepatic ischemia-reperfusion (I/R) injury. We examined the effects of inhaling high-concentration O2 on hepatic I/R injury with allopurinol, which is a xanthine oxidase inhibitor. Partial hepatic ischemia was performed in rats with or without allopurinol under 21 or 100% O2 inhalation. Levels of lipid peroxide, serum liver enzymes, and hepatocellular oxidative stress in the 100% O2 group were significantly higher than in the 21% O2. Administration of allopurinol significantly inhibited those changes in the 100% O2 group. Severe degeneration of mitochondria were noted in the 100% O2 group, but appeared to be reduced by allopurinol. Results suggest that inhalation of high-concentration O2 during liver surgery may increase lipid peroxidation and exacerbate hepatic I/R injury, but those changes may be prevented by allopurinol.

Ventral pancreatitis in a patient with pancreas divisum.

Pancreas divisum results in drainage of most pancreatic secretions through the minor papilla via the dorsal duct, and the association of minor papilla stenosis has been implicated as a cause of pancreatitis. Most of the reported cases represent pancreatitis confined to the dorsal part. The authors treated a 10-year-old boy with recurrent pancreatitis that was substantially more severe in the ventral part. The patient was referred with a brief history of abdominal pain and had undergone a laparotomy when segmental ventral pancreatitis had been observed. Severe pancreatitis and acute renal failure developed, which required drainage of the lesser sac and hemodialysis, respectively. After 5 months, he had another episode that subsequently led to a pseudocyst in the ventral part. Endoscopic retrograde cholangiopancreatography via minor papilla showed a normal-caliber dorsal duct communicating with a part of the fine ventral ducts. A normal biliary tree was shown, but no ventral duct was visualized by cannulation to the major papilla of Vater. Dual sphincteroplasties and a cholecystectomy were performed. The minor papilla was stenotic and admitted only the finest lacrimal duct probe. The orifice of the ventral duct could not be observed. Thus it was clarified that the dorsal duct with its stenotic orifice had drained both the dorsal and ventral pancreas. The patient has remained asymptomatic over 36 months postoperatively. Despite their limited experience, the authors believe that (1) this anatomic variant led to ventral pancreatitis, and (2) the sphincteroplasty of the minor papilla was successful.

Hepatocellular carcinoma in a patient with acromegaly and high serum levels of insulin-like growth factor I: Report of a case

Abstract.A 64-year-old woman with high serum levels of growth hormone, insulin-like growth factor-I (IGF-I), and α-fetoprotein resulting from partially treated acromegaly was found to have a tumor under the left diaphragm. The patient also had a history of type C viral hepatitis. Laparotomy revealed that the tumor was fixed to the diaphragm and connected to the liver and spleen. The tumor was excised with partial resection of the diaphragm, liver, and spleen, and a diagnosis of left-sided pedunculated hepatocellular carcinoma (HCC) was made. Further examination showed a higher level of IGF-I receptor mRNA in the tumor than in the normal liver parenchyma. We believe it is likely that the high serum levels of IGF-I may have played a role in the development of the pedunculated HCC in this patient.

Proximal-type epithelioid sarcoma in a 36-year-old man: Closer immunoelectron-microscopic resemblance of the tumor cells to epithelial cells than to mesenchymal cells

Proximal‐type epithelioid sarcoma (PES) is a rare neoplasm. We report a case of PES that arose in the perineal subcutis of a 36‐year‐old Japanese man who died within 4 months of the first clinical sign, probably due to massive pulmonary metastases. In the present study, we analyzed the tumor obtained at surgery, immunohistochemically, immunoelectron‐microscopically and genetically. Although the tumor cells in the patient expressed both cytokeratin and vimentin immunohistochemically, they showed epithelial characteristics immunoelectron‐microscopically because they had tonofilaments constructed of cytokeratin, not vimentin. In addition, the cytokeratins expressed on the tumor were glandular‐type keratins. These findings indicate that PES may be a form of carcinoma in soft tissue. To ascertain the possible origin of the tumor, we compared the tumor immunohistochemically with fetal tissues. Although notochord and fetal peritoneal mesothelium were similar to the tumor antigenically, we could not confirm the specific origin of the tumor. Furthermore, the p53‐WAF1 pathway did not contribute to tumorigenesis in the patient because the tumor had no mutation in exons 5–8 of the p53 gene and was immunohistochemically positive for WAF1.

Heparin reduces serum levels of endothelin-1 and hepatic ischemia reperfusion injury in rabbits

Since the role of heparin in hepatic ischemia/ reperfusion (I/R) injury is still not fully understood, we investigated the effects of heparin on hepatic I/R injury in rabbits. Heparin was injected into rabbits after inducing partial hepatic ischemia for 1 h. Thereafter, the serum levels of endothelin-1 (ET-1) and liver transaminase, and tissue levels of oxidized and deoxidized hemoglobin (oxHb, deoxHb) in the reperfused liver were analyzed. Microscopic examinations were also performed. The increased serum levels of ET-1 and liver transaminase after reperfusion were significantly reduced by heparin (P>0.01). Hepatic ischemia reduced oxHb and increased deoxHb. Reperfusion with heparin immediately reduced deoxHb and increased oxHb, and thereafter the balance between the two kinds of Hb also recovered. However, reperfusion without heparin did not demonstrate any similar recovery, but instead gradually exacerbated the dissociation. Microscopically, heparin appeared to normalize I/R-induced activation of hepatic stellate cells which are the target cells for ET-1. These results suggest that heparin improves the hepatic I/R injury caused by sinusoidal microscirculatory disturbances partly via an inhibition of the ET-1 increase.