GALLSTONE CIRRHOSIS: ARE WE ONLY SEEING THE TIP OF THE ICEBERG?

Gallstones are common and their incidence increases with age.¹ Fifty per cent of these stones are in the common bile duct (CBD) in the elderly.² Most of them are silent but with time there is an increasing chance of developing symptoms which are more likely to be serious in the elderly.³ Failure to relieve mechanical obstruction of bile flow may lead to secondary biliary cirrhosis.⁴ It has been estimated that on average secondary biliary cirrhosis develops some seven years after the onset of obstruction from a stricture, four and half years after gallstone obstruction and 10 months after the onset of malignant stricture.⁵ The characteristic features are the pathological findings of portal-portal linkages, with a pattern of monolobular cirrhosis and the preservation of normal vascular relationships.⁶ Secondary biliary cirrhosis may lead to hepatic insufficiency and portal hypertension with the resultant complications, such as bleeding oesophageal varices, hypersplenism with pancytopenia, ascites and encephalopathy. We describe a patient in whom the diagnosis was not suspected until laparotomy and confirmed only at autopsy.     

Expression of alpha-melanocyte stimulating hormone and the invasive ability of the B16 murine melanoma.

The expression of alpha melanocyte stimulating hormone (MSH) has been investigated in two variants of the B16 murine melanoma. The presence of MSH was demonstrated by immunohistochemical methods using anti-MSH antibodies. The low metastasis variant B16-F1, which grows as an encapsulated non-invasive tumour, showed no alpha-MSH immunoreactivity. In contrast, the high metastasis variant BL6 was found to be alpha-MSH positive and the immunoreactivity was found predominantly in the peripheral invading zones of the tumour.     

Effect of nitric oxide on mitogenesis and proliferation of cerebellar glial cells

In the brain, nitric oxide (NO) has been identified as a messenger molecule and a mediator of excitatory amino acid-induced neurotoxicity. In this study, the effects of NO on serum-induced mitogenesis and cell proliferation of the cerebellar glial cells were assessed. NO-generating agent, S-nitroso-N-acetylpenicillamine (SNAP) increased intracellular cyclic guanosine monophosphate (cGMP) levels. Furthermore, 2 chemically dissimilar NO-generating agents, SNAP and sodium nitroprusside (SNP) inhibited serum-induced thymidine incorporation and cell proliferation. The antimitogenic effect of NO was mimicked by 8-bromo-cGMP and blocked by hemoglobin, a known inhibitor of NO. The effect of NO was not cytotoxic, since the cells were not stained with Trypan blue and did not show increased release of lactate dehydrogenase in the culture supernatants. However, NO-treated cells showed decreased conversion of tetrazolium to blue formazan suggesting that NO inhibited mitochondrial activity in the glial cells. These results demonstrate that NO inhibits serum-induced mitogenesis and cell proliferation of cultured rat cerebellar glial cells.     

Influence of sugars on the activity of cellulase system from two basidiomycetes cultures

Influence of some sugars was studied on activity of purified cellulase enzymes produced by two white-rot basidiomycetes cultures in submerged fermentation. Exo- and endo-glucanases were found to be stimulated by glucose, sucrose and xylose, but β-glucosidase was inhibited by all sugars tested except sucrose being neutral. Cellobiose severely inhibited all three cellulase activities at all three concentrations taken in reaction mixture.     

Pharmacokinetics of Anandron in patients with advanced carcinoma of the prostate

Summary The pharmacokinetics of total radioactivity and unchanged drug were studied in patients receiving Anandron (Nilutamide, RU 23908) after a single dose of [¹⁴C] Anandron and after q12 h dosings of unlabelled drug for 2–7 weeks. The results indicate that the radioactivity in plasma consists of unchanged drug and metabolites. The plasma decay of Anandron after the absorption phase was biexponential in all patients, with the terminal phase half-life ranging from 23.3–87.2 h. The plasma decay of total radioactivity after the absorption phase was biexponential in 3/12 and monoexponential in 9/12 patients. The calculated terminal phase half-lives for total radioactivity after [¹⁴C] Anandron were 34.5–137.3 h. The AUC_0– of the unchanged drug in plasma represented 23%–38% of the AUC_0– of total radioactivity. Urinary radioactivity consisted primarily of metabolites, the majority of which were chloroform-nonextractable. Urinary excretion of radioactivity at 120 h ranged from 49%–78% of the administered dose; the unchanged Anandron (at 72 h) was 0.6%–1.3% of the dose. In three patients studied, the fecal excretion of Anandron was 1.4%–7.0%. Steady-state plasma levels (4.4–8.5 g/ml) were attained within approximately 2 weeks from the initiation of twice daily dosing of Anandron. When the plasma pharmacokinetics of radioactivity and unchanged drug after the first single dose were compared with that during steady state, AUC_{0–12 h} of unchanged Anandron during steady state was significantly higher than the AUC_0– after the first single dose, suggesting that the plasma clearance of Anandron is lowered upon chronic administration of the drug, assuming that the bioavailability is constant.