New hepatic vein reconstruction in left liver graft.

The incidence of hepatic venous stenosis is higher in partial liver transplantation. New methods for hepatic venous reconstruction in left liver transplantation, which secure wide anastomosis, were devised and are reported here. In the graft, the right side of the middle hepatic vein or the left side of the left hepatic vein was cut longitudinally and a rectangular-shaped vein patch was attached for venoplasty. In the recipient, after the left and middle hepatic veins were joined, the right side of the middle hepatic vein was cut toward the closed right hepatic vein, making a horizontal cavotomy for anastomosis. Of 92 patients who underwent conventional hepatic vein reconstruction, 3 were complicated by hepatic venous stenosis (median follow-up 43 months). By contrast, there were no hepatic vein complications in the 20 patients who underwent the new technique (7 months). The current method appears to be technically feasible for outflow reconstruction in left liver graft transplantation.     

Amino acid substitution at position 226 of the hemagglutinin molecule of influenza (H1N1) virus affects receptor binding activity but not fusion activity

The receptor binding site of the hemagglutinin (HA) molecule of type A influenza virus A/USSR/90/77 (H1N1) has been studied. Site-specific mutagenesis has been used to introduce base changes into the sequence that codes for the amino acid residue at position 226 on the HA molecule, and mutant sequences replaced the wild-type sequence of the HA gene of the SV40-HA recombinant virus (SVHA). Mutant HA proteins were expressed in African green monkey kidney cells and analyzed for receptor binding and fusion activities. Two mutant HA proteins containing single amino acid substitutions of Asn and Met for Gln at position 226 retained their receptor binding activity, but others with amino acid substitutions Glu, His, Leu, Val, and Thr for Gln at position 226 lost this activity. All the mutant proteins retained their fusion activity. On the other hand, another four mutants containing single amino acid substitutions at positions other than 226 retained the receptor binding and fusion activities, despite the drastic change in charge or polarity to the respective amino acids. These results suggest that amino acid residue 226 of the H1 subtype of HA is critical for receptor binding activity of the HA protein. Our results also show that the lack of receptor binding activity of the HA protein does not affect fusion activity.     

Influenza encephalopathy and encephalitis

Cleavage of the hemagglutinin (HA) molecule by proteases is a prerequisite for the pathogenicity and even for the neurovirulence of influenza A viruses. WSN, a neurovirulent virus, adapted to mouse brain, grew in vitro in several types of cells including neuroblastoma cells in the absence of trypsin. When mice were intracerebrally inoculated with WSN, the viral antigen was found in the substantia nigra zona compacta and hippocampus. The mice inoculated with viruses isolated from children with acute encephalopathy associated with an influenza virus infection, on the other hand, showed no neurological symptoms. Furthermore, these viruses did not grow in the human neuroblastoma and glioblastoma cells. Since 1991, most of the human influenza A viruses have not agglutinated chicken erythrocytes. Whether this altered receptor binding specificity is related to the occurrence of influenza encephalitis and encephalopathy is now under investigation.     

High-grade neuroepithelial tumor with BCL6 corepressor-alteration presenting pathological and radiological calcification: A case report

A 5-year-old girl presented with headache and vomiting. Head computed tomography and magnetic resonance imaging showed a right frontal lobe tumor with marked calcification. The patient underwent resection surgery with suspicion of anaplastic ependymoma, and the tumor was gross totally removed. Pathological examination revealed areas of dense tumor cells with a high nucleocytoplasmic ratio and myxoid areas consisting of tumor cells with a round-shaped nucleus and eosinophilic cytoplasm. Perivascular pseudorosette, necrosis, circumscribed growth, and microcalcification were also observed. Immunohistochemistry demonstrated negative staining for glial fibrillary protein and epithelial membrane antigen. Diagnosis of a high-grade neuroepithelial tumor (HGNET) with BCL6 corepressor (BCOR) alteration was made based on pathological findings and internal tandem duplication in the exon 15 of BCOR. Although calcification on radiological and pathological examination is not typical, it would be essential to recognize that calcification could appear in HGNET-BCOR.     

Renal cyst pseudoenhancement with beam hardening effect on CT attenuation

PURPOSE: The purpose of this study was to evaluate the extent of pseudoenhancement in a phantom model using three different CT scanners. METHODS: The phantom consisted of a water-filled balloon (cyst) suspended in varying concentrations of iodine solution, meant to simulate varying levels of renal enhancement. The phantom was scanned with single detector-row CT scanners of three different manufacturers. All scans were performed at 120 kV and 200 mA with 5 mm collimation. RESULTS: The degree of pseudoenhancement differed among the three scanners. In two of the scanners, the attenuation of water in the balloon (cyst) was noted to increase significantly as the iodine concentration in the cylinder was increased. However, the degree of pseudoenhancement was different between the two scanners. In the other scanner, attenuation of the cyst was noted to decrease as the iodine concentration in the cylinder decreased and to increase as the iodine concentration in the cylinder increased. CONCLUSION: The degree of pseudoenhancement may vary in scanners of different manufacturers. We may need to check the pattern and degree of pseudoenhancement in CT scanners before determining the enhancement threshold for simple renal cyst.     

CT demonstration of dilated gonadal vein as a portosystemic shunt of mesenteric varices

PURPOSE: The purpose of this work was to assess CT demonstration of the enlarged gonadal vein as a portosystemic shunt of mesenteric varices. METHOD: The clinical records and CT images of eight patients with angiographically confirmed mesenteric varices were studied retrospectively. We measured the size of the right gonadal vein of these eight patients and also measured the size of the right gonadal vein in 60 patients without mesenteric varices. RESULTS: In all eight patients, CT demonstrated that the mesenteric varices drained into the inferior vena cava through the dilated right gonadal vein (diameter 6-10 mm) in all and that the left gonadal vein was not dilated (diameter 2-3 mm). In 60 patients without mesenteric varices, the diameter of the right gonadal vein was 1-5 mm. CONCLUSION: CT demonstrates the dilated gonadal vein as a portosystemic shunt of the mesenteric varices. Awareness of a dilated gonadal vein in patients with portal hypertension may be helpful to consider the possibility of mesenteric varices.