Differential diagnosis of low-attenuation splenic lesions on computed tomography.

A retrospective computed tomography evaluation of proved low-attenuation splenic lesions in nontraumatic cases was done. Computed tomography was able to distinguish cystic from solid lesions. Although computed tomography examination is sensitive in the detection of low-attenuation lesions, the computed tomography findings alone are not helpful in differentiation of different low-attenuation lesions.

ATP-dependent unwinding of messenger RNA structure by eukaryotic initiation factors.

Interaction of protein synthesis initiation factors with mRNA has been studied in order to characterize early events in the eukaryotic translation pathway. Individual reovirus mRNAs labeled with 32P in the alpha position relative to the m7G cap and eukaryotic initiation factor (eIF)-4A, -4B, and -4F purified from rabbit reticulocytes were employed. It was found that eIF-4A causes a structural change in mRNA, as evidenced by a nuclease sensitivity test: addition of high concentrations of eIF-4A greatly increase the nuclease sensitivity of the mRNA, suggesting that this factor can melt or "unwind" mRNA structure.

Test of catechol, tannic acid, Bidens pilosa, croton oil, and phorbol for cocarcinogenesis of esophageal tumors induced in rats by methyl-n-amylnitrosamine.

Catechol (CAS: 120-80-9), given in drinking water to rats, was the most effective of 5 phenols in enhancing [3H]thymidine incorporation [( 3H]dThd-l) into esophageal DNA. To test for esophageal cocarcinogenesis, groups of 30 male MRC-Wistar rats received 3 weekly ip injections of 25 mg methyl-n-amylnitrosamine [(MNAN) CAS: 13256-07-0]/kg. From the time of the first MNAN injection, each group also received catechol, tannic acid (CAS: 1401-55-4), dried leaves of Bidens pilosa L.

Changes in endogenous DNA damage in aging mice in response to butylated hydroxyanisole and oltipraz.

The extent of DNA damage (single strand breaks) was measured in the livers of female Swiss-Webster mice up to 24 months of age. The effects of the antioxidants butylated hydroxyanisole (BHA) and oltipraz on this DNA damage were also measured. Oltipraz is an antioxidant which is structurally related to compounds found in cruciferous vegetables.

Evaluation and treatment of intraabdominal bilomas.

In a 3-year period, 21 intraabdominal bilomas developed in 18 patients. Fifteen of the patients had a solitary biloma, and the other three patients each had two separate concurrent bilomas. The major cause of biloma formation was postoperative bile leakage from a bile duct after laparotomy done primarily for surgery on the gallbladder or liver.

Compression of the right pulmonary artery by aortic aneurysms: CT demonstration.

Two cases are presented in which compression of the right pulmonary artery by thoracic aortic aneurysm was demonstrated using dynamic CT. The patients initially presented with symptoms suggestive of pulmonary embolus and were found to have unilateral absence of perfusion on isotope lung scan. Computed tomography was useful in demonstrating pulmonary artery compression by aortic aneurysm as the cause in both cases, and in demonstrating an aortic dissection in one case.

Modification of pancreatic carcinogenesis in the hamster model. XV. Preventive effect of nicotinamide.

The induction of pancreatic ductal-ductular adenomas (P = .05) and carcinomas (P less than .0001) by N-nitrosobis(2-oxopropyl)amine [(BOP) CAS: 60599-38-4; 2,2'-dioxo-N-nitrosodipropylamine] in Syrian golden hamsters was inhibited by nicotinamide (NA) (350 mg/kg body wt, ip) administered 10 minutes before and 3 hours after a single dose of BOP (10 mg/kg body wt, sc).

Primary biliary carcinoma: CT evaluation.

Fifty-three patients with documented primary biliary carcinoma were studied with computed tomography. Twenty-six patients had gallbladder carcinoma and 27 patients had carcinoma of the biliary ductal system. Ninety percent of patients with gallbladder cancer had an intraluminal mass.

Persistence of DNA single-strand breaks and other tests as indicators of the liver carcinogenicity of 1-nitroso-5,6-dihydrouracil and the noncarcinogenicity of 1-nitroso-5,6-dihydrothymine.

The cyclic nitrosourea 1-nitroso-5,6-dihydrothymine [(NDHT) 1-nitrosodihydrothymine] was not significantly carcinogenic when it was administered for 1 year in drinking water (206 mg/liter) to MRC-Wistar rats. In acute toxicity tests, ip injection of saline solutions of 1-nitroso-5,6-dihydrouracil [(NDHU) CAS: 16813-36-8; 1-nitrosohydrouracil], a strong liver carcinogen in rats, produced only mild liver toxicity but marked focal degeneration of myocardial fibers. NDHU injected ip in water solution produced subcapsular liver damage.

Intravenous DSA examination of patients with suspected cerebral ischemia.

We analyzed the role of intravenous digital subtraction angiography (DSA), with neck and intracranial views as a definitive pretherapy study, in patients who had symptomatic cerebral ischemia. Eighty-six patients, 25 of whom had subsequent carotid thromboendarterectomy, were examined. An adequate pretherapy intravenous DSA study allowed us to define each carotid bifurcation as either normal, having insignificant stenosis, or having significant stenosis, and the examination excluded significant tandem stenosis in the intracranial internal carotid arteries.

CT appearance of Mirizzi syndrome.

Mirizzi syndrome consists of extrinsic compression of the common hepatic duct by gallstones in patients with cholecystitis. Computed tomography done with techniques that optimize spatial resolution may aid diagnosis by permitting identification of the precise level of and the extrinsic nature of the obstruction.

Changes in glutathione and glutathione metabolizing enzymes in erythrocytes and lymphocytes of mice as a function of age.

Changes in reduced glutathione levels in liver, lung and whole blood of female Swiss-Webster mice with age were determined. In addition, glutathione content, and glutathione S-transferase and glutathione reductase activities of erythrocytes and lymphocytes of mice as a function of age were examined. Reduced glutathione content increased in liver, lung, whole blood, erythrocytes and lymphocytes with age from 3 to 9 months, reached a maximum level at 9 months of age and decreased thereafter with advanced age in all tissues.

Modification of pancreatic carcinogenesis in the hamster model. XI. Inhibitory effect of pilocarpine hydrochloride.

Pilocarpine hydrochloride (PH) was administered as a single sc injection (15 mg/kg body wt) to outbred Syrian golden hamsters either prior to, simultaneously with, or after a single 20-mg/kg body weight dose of the pancreatic carcinogen N-nitrosobis(2-oxopropyl)amine (BOP). An additional group was treated with PH, once before and once simultaneously with BOP; another group received PH daily for life after BOP and controls were given BOP only. Surviving hamsters were killed 46 weeks after BOP treatment.

Pancreatic carcinogenic nitrosamines in Syrian hamsters.

Pancreatic neoplasms similar to those seen in humans have been induced by a group of related nitrosamines only in Syrian golden hamsters. Studies indicate a relationship between the structure of the carcinogens and their affinity for the pancreas: the presence of one keto or hydroxy group in the beta-position on one of the aliphatic chains of alkyl nitrosamines is a prerequisite for their pancreatic carcinogenicity; addition of a second beta-keto group significantly increases their activity on and specificity for the pancreas; replacement of one 2-oxo chain with a methyl group diminishes their specificity for the pancreas as does prolongation of the aliphatic chain. Carboxylation at the 3-position is associated with a complete loss of pancreatotropism.

Comparative metabolism of beta-oxidized nitrosamines.

Several beta-oxidized nitrosamines have been shown to induce pancreatic cancer in Syrian hamsters. N-Nitrosobis(2-oxopropyl)amine (ND2OPA) is the most specific, but it also induces either colonic or prostatic tumours in MRC-Wistar rats. In-vivo and in-vitro metabolic studies show that N-nitrosomethyl(2-oxopropyl)amine is a metabolite of ND2OPA in hamsters but not in rats.

Exocrine pancreatic secretion in the Syrian golden hamster Mesocricetus auratus--III. Effects of carcinogen administration and development of pancreas cancer.

The short- and long-term effects of the administration of the pancreas carcinogen N-nitrosobis(2-oxopropyl)amine (BOP) on pancreatic exocrine secretion were examined in Syrian hamsters with and without stimulation by secretin and pancreozymin. Protein concentration, flow rate, pH and ion content, (Na+, K+, Ca2+, Mg2+, HCO3-, Cl-, HPO4(2-) and SO4(2-)) were measured. An immediate effect of BOP is the stimulation of flow rate in females and of protein secretion in both sexes.

Carcinogenicity of N-nitrosomethyl(2-oxobutyl)amine and N-nitrosomethyl-(3-oxobutyl)amine in Syrian hamsters with special reference to the pancreas.

Studies with oxidized derivatives of N-nitrosodi-n-propylamine suggested a structure-activity relationship between pancreatic cancer induction in Syrian hamsters and position and degree of nitrosamine oxidation. To elucidate the importance of the position of the oxidized substituent relative to the N-nitroso group in pancreatic carcinogenesis, we compared the toxicity and carcinogenicity of two substituted methylbutylnitrosamines. N-Nitrosomethyl(2-oxobutyl)amine (M-2-OB) and N-nitrosomethyl(3-oxobutyl)amine (M-3-OB) were given in equitoxic doses to male and female Syrian hamsters.

Dissecting aortic aneurysms: accuracy of computed tomographic diagnosis.

During a three-year period, fifty patients were evaluated for the possibility of dissecting aortic aneurysm using high-resolution computed tomography (CT). The diagnosis of dissection was made if two contrast-medium-filled channels were identified within the aortic lumen. Eighteen patients were diagnosed with CT as having dissecting aortic aneurysms.

Acute pancreatitis and its complications. Computed tomography and sonography.

Acute pancreatitis is a clinical diagnosis. In most patients with uncomplicated acute pancreatitis, there is no need for radiologic confirmation or work-up. However, in some patients, the diagnosis may be in doubt, or associated abnormalities or complications of acute pancreatitis may be suspected by the patient's protracted course or severity of disease.

Separation of synthetic oligonucleotides on columns of microparticulate silica coated with crosslinked polyethylene imine.

A rapid and effective method for separating oligonucleotides using high-performance ion-exchange chromatography is described. Columns were prepared by adsorbing a layer of polyethylene imine on 5-micron-diameter porous silica followed by crosslinking with a multifunctional oxirane. This weak anion-exchange matrix was found to be useful in the separation of mononucleotides and oligonucleosides containing up to 20 residues in either homo- or heteropolymers.

Enhancement of the repair of carcinogen-induced DNA damage in the hamster pancreas by dietary selenium.

We measured single strand breaks (SSB) in pancreas DNA produced by N-nitrosobis (2-oxopropyl)amine (BOP) in hamster fed purified diets containing added sodium selenite (Se) at 0.0, 0.1 and 5.