Histological and nonhistological criteria in the evaluation of liver involvement in chronic hepatitis C.

The treatment of chronic viral hepatitis is based mainly on interferon therapy. This therapy has many drawbacks, among which potentially dangerous side-effects. Moreover, the majority of the patients are asymptomatic at the time of diagnosis, and most of them will never develop cirrhosis, liver failure or hepatocellular carcinoma, making the decision to treat a difficult one. Currently, the best method of selection is liver biopsy, considered "the gold standard" for recommending antiviral treatment. The histological aspect can vary in different hepatic areas and the smaller the bioptic fragment, the more probable is the histopathologist's error in correctly defining the hepatitis. There has been made important progress in defining the degree of liver involvement using serological tests, with the purpose of avoiding liver biopsy, but this approach has not yet proven to be superior. At present, the benefits of the pretreatment liver biopsy outbalance the risks. The future developments in the domain of antiviral drugs or nonhistological tests for evaluating the liver injury (circulating cytokines, subtypes of collagen) will show if the liver biopsy could be abandoned.

Distribution of ozone and other air pollutants in forests of the Carpathian Mountains in central Europe.

Ozone (O3) concentrations were monitored during the 1997-1999 growing seasons in 32 forest sites of the Carpathian Mountains. At all sites (elevation between 450 and 1320 m) concentrations of O3, nitrogen dioxide (NO2), and sulfur dioxide (SO2) were measured with passive samplers. In addition, in two western Carpathian locations, Vychodna and Gubalówka, ozone was continuously monitored with ultraviolet (UV) absorption monitors. Highest average hourly O3 concentrations in the Vychodna and Gubalówka sites reached 160 and 200 microg/m3 (82 and 102 ppb), respectively (except for the AOT40 values, ozone concentrations are presented as microg/m3; and at 25 degrees C and 760 mm Hg, 1 microg O3/m3 = 0.51 ppb O3). These sites showed drastically different patterns of diurnal 03 distribution, one with clearly defined peaks in the afternoon and lowest values in the morning, the other with flat patterns during the entire 24-h period. On two elevational transects, no effect of elevation on O3 levels was seen on the first one, while on the other a significant increase of O3 levels with elevation occurred. Concentrations of O3 determined with passive samplers were significantly different between individual monitoring years, monitoring periods, and geographic location of the monitoring sites. Results of passive sampler monitoring showed that high O3 concentrations could be expected in many parts of the Carpathian range, especially in its western part, but also in the eastern and southern ranges. More than four-fold denser network of monitoring sites is required for reliable estimates of O3 distribution in forests over the entire Carpathian range (140 points). Potential phytotoxic effects of O3 on forest trees and understory vegetation are expected on almost the entire territory of the Carpathian Mountains. This assumption is based on estimates of the AOT40 indices for forest trees and natural vegetation. Concentrations of NO2 and SO2 in the entire Carpathian range were typical for this part of Europe and below the expected levels of phytotoxicity.