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Biomedical subjects

M Viamonte

Publications and source records attributed to M Viamonte.

122 records · Page 7Linked to original sources
PubMedDate not supplied

Hepatic encephalopathy and orotic aciduria associated with hepatocellular carcinoma in a noncirrhotic liver.

A 40-yr-old man presented with encephalopathy and was found to have hepatocellular carcinoma without cirrhosis. A large vascular hepatic mass was defined by CT scan and angiography; laparoscopy with biopsy confirmed the absence of chronic liver disease. A definitive tissue diagnosis of hepatocellular carcinoma was made at laparotomy; the tumor was unresectable. Peripheral arterial and selective portal and hepatic venous ammonia levels were high, and this finding suggested that the encephalopathy was nitrogenous and hepatic in origin. The proposed mechanisms of the encephalopathy are generation of ammonia from tumor breakdown and portosystemic shunting, a result of partial tumor occlusion of the hepatic veins. An unusually high urinary excretion of orotic acid was found similar to that seen in hereditary orotic aciduria.

Adult↗
PubMedDate not supplied

MR of visual pathways in patients with neurofibromatosis.

MR was performed on six patients clinically diagnosed as having neurofibromatosis. Owing to its multiplanar capability, MR greatly helped determine the extent of visual pathway disease. We attempted to find specific optimal pulse sequences for evaluating the prechiasmatic, chiasmatic, and retrochiasmatic visual system at 0.35 T. Using spin-echo techniques, we evaluated a T1-weighted sequence (TR 300 msec/TE 35 msec), an intermediate T2-weighted sequence (TR 1500 msec/TE 35 msec), and a T2-weighted sequence (TR 1500 msec/TR 70 msec). We found that the orbital and intracanalicular optic nerves were most accurately and easily seen with the T1-weighted sequence axially and coronally; the chiasm was best seen with the intermediate T2-weighted coronal sequence; and the retrochiasmatic visual pathway was optimally evaluated with T2-weighted spin-echo technique.

Child↗
PubMedDate not supplied

Gastrointestinal hemorrhage: angiodiagnosis and angiotherapy.

Angiographic methods cannot and should not be applied to every patient with GI bleeding. Three out of four patients stop bleeding with conservative measures (bed rest, volume replacement, sedation, etc.). Major indications for angiography: patients who continue to bleed, despite conservative measures; when endoscopy is not available, is contraindicated, or inconclusive; when other diagnostic tests and/or laparotomy have failed to demonstrate the site and cause of bleeding. Angiography must be available at all times, and must be performed with expediency and with competence.

Angiography↗