The effect of different calcium antagonists and a calcium agonist on the metabolism of propranolol by isolated rat hepatocytes

Summary— The influence of the dihydropyridine calcium entry blockers nicardipine, amlodipine, nifedipine, isradipine and of the dihydropyridine calcium entry promotor BAY K 8644 on the disappearance rate of propranolol by isolated rat hepatocytes was compared to the effect of diltiazem and verapamil, two non-dihydropyridine calcium channel blockers and known inhibitors of hepatic cytochrome P450 mixed function oxidases. All compounds dose-dependently inhibited the disappearance rate of propranolol. Nicardipine and isradipine were more potent in inhibiting the disappearance rate of propranolol than the other dihydropyridines and than diltiazem and verapamil. The inhibitory effect of nicardipine on the disappearance rate of propranolol was not stereoselective and was not influenced by age.     

Interleukin-4 inhibits indoleamine 2,3-dioxygenase expression in human monocytes

Indoleamine 2,3-dioxygenase (IDO), a flavin-dependent enzyme that catalyzes the conversion of tryptophan to kynurenine, is induced in peripheral blood mononuclear cells by interferon-gamma (IFN gamma). Interleukin-4 (IL-4) is a cytokine that modulates the functional properties of monocytes/macrophages, and we investigated the effects of IL-4 on IDO. We showed that IL-4 inhibited the induction of IDO mRNA and IDO activity by IFN gamma in human monocytes. The inhibitory effect was evident with as little as 2 U/mL of IL-4. These results provide the first evidence that a cytokine can provide a negative signal for IDO expression and that IL-4 can influence the catabolism of tryptophan.     

Bone scintigraphy in chondroblastoma

Scintigraphy in 3 patients with chondroblastoma showed that the tumors were hyperemic and avidly accumulated the radionuclide. These changes were also present in adjacent normal bone, but to a lesser degree. This suggest that radionuclide uptake in chondroblastoma is a function of the blood supply to the tumor rather than primary matrix extraction.     

Congenital hepatic artery aneurysm simulating pancreatic carcinoma

The authors report a case of a hepatic artery aneurysm that simulated a mass in the head of the pancreas. The correct diagnosis was made preoperatively based on several findings: curvilinear calcification within the mass on CT, a well-defined cystic collection on ultrasound, absence of biliary duct dilatation or jaundice, and presence of other aneurysms.     

Phrygiasterol, a cytotoxic cyclopropane-containing polyhydroxysteroid, and related compounds from the pacific starfish Hippasteria phrygiana

The new cyclopropane-containing steroid phrygiasterol (1) and steroid glycoside phrygioside B (2), along with previously known borealoside C (2a) and (20R,24S)-5alpha-cholesta-3beta,6alpha,8,15alpha,24-pentaol (3), have been isolated from the Pacific starfish Hippasteria phrygiana. On the basis of spectroscopic analyses, using 1D and 2D NMR techniques and some chemical transformations, the structures of 1 and 2 have been established as (20R,24R,25R)-24,26-cyclo-5alpha-cholesta-3beta,6alpha,8,15alpha,16beta,27-hexaol (1) and the sodium salt of (20R,24S)-24-O-(3-O-methyl-4-O-sulfate-beta-d-xylopyranosyl)-5alpha-cholesta-3beta,6alpha,8,15alpha,24-pentaol (2), respectively. Compound 1 inhibited the growth of Ehrlich carcinoma cells with an IC(50) of 50 microg/mL, whereas 2 induced apoptosis of the same cells (EC(50)=70 microg/mL) and inhibited Ca(2+) influx into mouse spleenocytes (EC(50)=20microg/mL).