Okayama University Medical School

An unusual case of orbital tumor with high renin content and severe hypertension is described. The patient was a 15-year-old girl with juvenile hypertension (200-140 mmHg) associated with right exophthalmos and hypokalemia. The patient showed extremely high levels of plasma renin activity and plasma aldosterone concentration. No difference was present in plasma renin activity from either side of the renal veins. Preoperatively, hypertension responded to treatment with spironolactone. The tumor could not be completely removed because of intracranial metastasis and infiltration, and the hyperreninemia and secondary hyperaldosteronism persisted. The renin content in the orbital tissue was 1,403-2,225 ng/angiotensin I generated/h/g wet weight of tissue. The postmortem histopathologic diagnosis was orbital hemangiopericytoma. This is the first case of extrarenal (ectopic) renin-secreting (or -producing) hemangiopericytoma of the orbital origin. Furthermore this case is worthy of note in the point of view of the presence of the extrarenal renin-angiotensin system, particularly in the brain.

A 44-year-old man with alcohol-induced chronic pancreatitis was referred to our institute for evaluation of severe anemia. The hemoglobin was 2.6g/dl. The results of upper gastrointestinal and colonic examination were negative. Computed tomography and ultrasound examination revealed a pseudocyst in the head of the pancreas. A pseudoaneurysm of the anterior superior pancreaticoduodenal artery shown by angiography appeared to have caused gastrointestinal bleeding by rupturing into the pancreatic cyst connected to the main pancreatic duct. A pyrorus-preserving pancreaticoduodenectomy was performed successfully.

To clarify the nature of nitrogen metabolism between branched chain amino acid (BCAA) and glutamine (GIn) in liver failure, we measured arterial plasma concentrations of GIn and ¹⁵N uptake to amino-N and amide-N of GIn in normal and D-galactosamine-induced fulminant hepatic failure (FHF) rats after ¹⁵N-leucine (Leu) injection. Fifteen, 30 and 60 min after Leu injection, the arterial plasma concentrations of GIn were significantly higher in FHF rats than in controls. The concentrations of amino-¹⁵N GIn were also significantly higher in FHF rats than in controls at 5, 15, 30 and 60 min after injection. The concentrations of amide-¹⁵N GIn did not significantly differ between FHF and controls at 5, 15 and 30 min. However, at 60 min, the concentration was significantly higher in the FHF rats. The higher uptake of ¹⁵N to amino-N of GIn in FHF rats suggests the presence of an enhanced ability to synthesize GIn from Leu in FHF rats. The higher uptake of ¹⁵N to amide-N of GIn in FHF rats at 60 min after injection suggests that excessive administration of BCAA to patients with severely impaired urea-cycle capacity suffering with hepatic failure may lead to greater levels of hyperammonemia.

A novel endonuclease of 55-kDa was found in rat liver mitochondria by a zymographic assay, in addition to the 29 kDa enzyme that is well-known as endonuclease G (Endo G). Subcellular localization of these enzymes in rat liver cells was examined by biochemical fractionation. Endo G was located in both nuclei and mitochondria as has been previously reported, while the 55-kDa enzyme was only detected in the mitochondrial fraction. The levels of the endonucleases in the mitochondria varied greatly among the rat organs, and the activity in the heart was about 30 times higher than that in the liver. The 55-kDa enzyme and Endo G were extracted from bovine heart mitochondria with 0.4 M NaCl. During purification the 55-kDa enzyme and Endo G were copurified because of their similar chromatographic behavior, so they were separated by gel filtration or electrophoresis in the presence of SDS and the proteins were then renatured. The nucleolytic properties of the 55-kDa enzyme resembled those of Endo G and other known mitochondrial nucleases. The enzyme degraded single-stranded DNA more rapidly than duplex DNA at a weak alkaline pH, requiring Mg²⁺ or Mn²⁺ but not Ca²⁺ or Zn²⁺. Nicks generated by the enzyme had 5′-P and 3′-OH ends. The 55-kDa enzyme, like Endo G, displayed an unusually strong preference to nick within a (dG)_n · (dC)_n tract.

Chromosome studies were conducted on two patients with adult T-cell leukemia. In both patients, a marker chromosome 14q+ and a structural change involving chromosome 1 with trisomy of the q arm were found in peripheral blood leukocytes. The 14q+ marker chromosome had resulted from translocation from #5p in one patient and #5q in the other patient. The present and previous studies suggest that the donor chromosomes involved in the 14q+ translocation are variable. This indicates that the 14q+ marker chromosome rather than the donor chromosome is intimately related with adult T-cell leukemia.