Fungal diversity of Norway spruce litter: effects of site conditions and premature leaf fall caused by bark beetle outbreak.

Fungi play an important role in leaf litter decomposition due to their ability to break down the lignocellulose matrix, which other organisms are unable to digest. However, little is known regarding the factors affecting components of fungal diversity. Here, we quantified richness of internal fungi in relation to litter nutrient and phenolic concentrations, sampling season (spring or fall), and premature leaf shedding due to low precipitation and infestation of bark beetles (mainly Ips typographus and Ips duplicatus). The study was conducted in 37-year-old Norway spruce [Picea abies (L.) Karst.] stands, with three plots each in mixed forest (MF) and coniferous forest (CF) site conditions in south-central Poland. Fifty-four species of sporulating fungi were identified in 2,330 freshly fallen needles sampled during 2003-2005, including 45 species in MF and 31 in CF. The significantly higher number of species in MF was likely related to moister conditions at that site. Among isolated fungi, 22% (12 species) were identified as endophytes of Norway spruce in prior studies. During spring of 2005, we found less than half the number of isolates and fungal species at each forest site as compared to fall for the two prior years. This pattern was observed in typical soil fungi (e.g., Penicillium daleae, Penicillium purpurogenum) and endophytes/epiphytes (e.g., Aureobasidium pullulans, Alternaria alternata, Cladosporium spp., and Lophodermium piceae). Premature shedding of needles was the most likely cause of this decline because it shortened the time period for fungi to infect green needles while on the tree. For all sites and sampling periods, richness of internal fungi was strongly and positively related to the age of freshly fallen litter (assessed using needle Ca concentration as a needle age tracer) and was also negatively related to litter phenolic concentration. Richness of internal fungi in freshly fallen litter may be adversely affected by low soil moisture status, natural inhibitors slowing fungal colonization (e.g., phenolics) and biotic (e.g., insect infestation) and abiotic (e.g., drought) factors that shorten leaf life span.

Interaction of pefloxacin and enoxacin with the human cytochrome P450 enzyme CYP1A2.

BACKGROUND AND OBJECTIVES: Pefloxacin is reported to cause clinically relevant inhibition of theophylline metabolism in vivo, but in vitro pefloxacin was only a weak inhibitor of the cytochrome P450 CYP1A2, mediating main theophylline biotransformation. We therefore further characterized the interaction between pefloxacin and CYP1A2. METHODS: A randomized 3-period change-over study was conducted in 12 healthy young volunteers on the steady-state interactions between pefloxacin or enoxacin (400 mg twice a day) with caffeine (183 mg once daily), a validated marker of CYP1A2. Caffeine pharmacokinetics were estimated after its fifth dose. Studies in human liver microsomes were carried out to measure the effect of pefloxacin and norfloxacin on caffeine 3-demethylation, an in vitro CYP1A2 probe, and to identify the enzyme(s) that mediate pefloxacin N-4'-demethylation with selective inhibitors. RESULTS: For the in vivo study, ANOVA-based point estimates (90% confidence intervals [CI]) for the ratios of caffeine pharmacokinetics with and without pefloxacin coadministration were 1.11 for maximal steadystate plasma concentrations (Cmax,ss; 90% CI, 0.99 to 1.26), 0.53 for total clearance (CLt,ss; 90% CI, 0.49 to 0.58), and 1.04 for the beta-phase distribution volume (Vdbeta; 90% CI, 0.96 to 1.13). The values for enoxacin were 1.99 for Cmax,ss (90% CI, 1.77 to 2.23), 0.17 for CLt,ss (90% CI, 0.16 to 0.19), and 1.01 for Vdbeta (90% CI, 0.90 to 1.13). Thus pefloxacin caused a 2-fold decrease in caffeine clearance, and enoxacin caused a 6-fold decrease in caffeine clearance. In vitro, norfloxacin and pefloxacin competitively inhibited CYP1A2, with inhibition constant (Ki) values of 0.1 and 1 mmol/L, respectively, and CYP1A2 was the only enzyme with a relevant contribution (approximately 50%) to pefloxacin N-4'-demethylation. CONCLUSIONS: Enoxacin and to a lesser extent pefloxacin may cause clinically relevant interactions with further CYP1A2 substrates. The data suggest that the pefloxacin interaction is partly mediated by its major metabolite norfloxacin.

[Removal of clear cell carcinoma in a patient with bilateral polycystic kidney degeneration]. / Wyluszczenie raka jasnokomórkowego u chorej z obustronnymi nerkami torbielowatymi.

A case is described of enucleation of a renal clear-cell carcinoma in a patient with bilateral polycystic renal degeneration. The tissue defect after removed tumour was filled with tissue adhesive and catgut sutures. The patient is alive without evidence of recurrence 16 months after the operation.