15 research outputs found
Environmental risk assessment of human and veterinary medicinal products - Challenges and ways of improvement
A 90-Day Oral Toxicological Evaluation of the Methylurate Purine Alkaloid Theacrine
A 90-day repeated-dose oral toxicological evaluation was conducted according to GLP and OECD guidelines on the methylurate purine alkaloid theacrine, which is found naturally in certain plants. Four groups of Hsd.Brl.Han Wistar rats (ten/sex/group) were administered theacrine by gavage doses of 0 (vehicle only), 180, 300, and 375 mg/kg bw/day. Two females and one male in the 300 and 375 mg/kg bw/day groups, respectively, died during the study. Histological examination revealed centrilobular hepatocellular necrosis as the probable cause of death. In 375 mg/kg bw/day males, slight reductions in body weight development, food consumption, and feed efficiency, decreased weight of the testes and epididymides and decreased intensity of spermatogenesis in the testes, lack or decreased amount of mature spermatozoa in the epididymides, and decreased amount of prostatic secretions were detected at the end of the three months. At 300 mg/kg bw/day, slight decreases in the weights of the testes and epididymides, along with decreased intensity of spermatogenesis in the testes, and lack or decreased amount of mature spermatozoa in the epididymides were detected in male animals. The NOAEL was considered to be 180 mg/kg bw/day, as at this dose there were no toxicologically relevant treatment-related findings in male or female animals
A tavaszi hernyóbiomassza becslése lomberdőkben hosszú távú fénycsapda adatsorok alapján – Mit fognak enni az énekesmadár-fiókák?
Számos, nemrĂ©giben megjelent tanulmány változatos Ă©lĹ‘helyek ĂzeltlábĂş diverzitásának, biomasszájának Ă©s egyedszámának ijesztĹ‘ mĂ©rtĂ©kű csökkenĂ©sĂ©rĹ‘l számolt be. Ennek az ökolĂłgiai vonatkozása jelentĹ‘s lehet, hiszen ezen szervezetek más Ă©lĹ‘lĂ©nyeknek fontos táplálĂ©kául szolgálnak. Az ErdĂ©szeti FĂ©nycsapda HálĂłzat adatait használtuk annak megállapĂtására, hogy a tavaszi hernyĂł biomassza hosszĂştávĂş (23-58 Ă©v) változása mutat-e csökkenĹ‘ trendet tölgy dominálta erdeinkben. 6 helyszĂn 43 nagylepke fajára (hernyĂłik a madarak számára megfelelĹ‘ táplálĂ©kok) vonatkozĂł adatait használtuk az elĂ©rhetĹ‘ hernyĂł biomassza becslĂ©sĂ©hez. Az idĹ‘sorok elemzĂ©se erĹ‘s fluktuáciĂłt mutat Ă©vrĹ‘l Ă©vre, Ă©s összessĂ©gĂ©ben inkább növekvĹ‘, mint csökkenĹ‘ trendet találtunk. ErdĹ‘egĂ©szsĂ©gĂĽgyi vonatkozásokat figyelembe vĂ©ve ez a biomassza növekedĂ©s fokozott lombfogyasztással jár, Ăgy negatĂv hatása lehet. Elmondhatjuk, hogy azok a nagylepke fajok, melyek hernyĂłi tavasszal fejlĹ‘dnek, az elmĂşlt Ă©vtizedekben nem fogyatkoztak meg. Egyes fajok hernyĂłinak becsĂĽlt biomassza-növekedĂ©se az erdĹ‘egĂ©szsĂ©gre negatĂvan, azonban a madarak fĂ©szkelĂ©si sikeressĂ©gĂ©re pozitĂvan hathat
A tavaszi hernyóbiomassza becslése lomberdőkben hosszú távú fénycsapda adatsorok alapján – Mit fognak enni az énekesmadár-fiókák?
Számos, nemrĂ©giben megjelent tanulmány változatos Ă©lĹ‘helyek ĂzeltlábĂş diverzitásának, biomasszájának Ă©s egyedszámának ijesztĹ‘ mĂ©rtĂ©kű csökkenĂ©sĂ©rĹ‘l számolt be. Ennek az ökolĂłgiai vonatkozása jelentĹ‘s lehet, hiszen ezen szervezetek más Ă©lĹ‘lĂ©nyeknek fontos táplálĂ©kául szolgálnak. Az ErdĂ©szeti FĂ©nycsapda HálĂłzat adatait használtuk annak megállapĂtására, hogy a tavaszi hernyĂł biomassza hosszĂştávĂş (23-58 Ă©v) változása mutat-e csökkenĹ‘ trendet tölgy dominálta erdeinkben. 6 helyszĂn 43 nagylepke fajára (hernyĂłik a madarak számára megfelelĹ‘ táplálĂ©kok) vonatkozĂł adatait használtuk az elĂ©rhetĹ‘ hernyĂł biomassza becslĂ©sĂ©hez. Az idĹ‘sorok elemzĂ©se erĹ‘s fluktuáciĂłt mutat Ă©vrĹ‘l Ă©vre, Ă©s összessĂ©gĂ©ben inkább növekvĹ‘, mint csökkenĹ‘ trendet találtunk. ErdĹ‘egĂ©szsĂ©gĂĽgyi vonatkozásokat figyelembe vĂ©ve ez a biomassza növekedĂ©s fokozott lombfogyasztással jár, Ăgy negatĂv hatása lehet. Elmondhatjuk, hogy azok a nagylepke fajok, melyek hernyĂłi tavasszal fejlĹ‘dnek, az elmĂşlt Ă©vtizedekben nem fogyatkoztak meg. Egyes fajok hernyĂłinak becsĂĽlt biomassza-növekedĂ©se az erdĹ‘egĂ©szsĂ©gre negatĂvan, azonban a madarak fĂ©szkelĂ©si sikeressĂ©gĂ©re pozitĂvan hathat
No Long-Term Decrease in Caterpillar Availability for Invertivorous Birds in Deciduous Forests in Hungary
Numerous recent studies report an alarming decrease in diversity, biomass, or abundance of arthropods in various habitats. Given that they are important food for other organisms, the ecological consequences of such a decline could be severe. We used data from the Hungarian Forestry Light Trap Network to examine whether the spring caterpillar biomass showed any long term (23–58 years) declining trend in oak-dominated forests. Light trap data for 43 selected macrolepidopteran species (suitable bird food in the larval stage) from six different locations were used for the estimation of the total available caterpillar biomass. Time series analyses showed strong year-to-year fluctuations, and over all locations and time windows there was an increasing rather than decreasing trend. The increase found at some locations may suggest increasing herbivore pressure and negative impacts on forest health. We conclude that foliage-feeding macrolepidopteran species with spring-developing larvae did not show a drastic decrease in recent decades, and food availability in the long term will not negatively influence the breeding success of birds in such forests
A 28-day oral toxicology study of an aqueous extract of Polypodium leucotomos (Fernblock®)
Fernblock® is a standardized commercial aqueous extraction of the leaves of the tropical fern Polypodium leucotomos promoted as an orally active photoprotective substance. In a previous battery of toxicological tests on Fernblock®, no genotoxicy was observed and no oral toxicity was observed up to 1200 mg/kg bw/day. The current study was conducted in Hsd.Han Wistar rats using doses of 0, 2000, 3500, and 5000 mg/kg bw/day Fernblock® by gavage for 28 consecutive days. No mortality or toxic effects were observed and no target organs were identified. The no observed adverse effect level was determined to be 5000 mg/kg bw/day, the highest dose tested. Keywords: Polypodium leucotomos, Toxicology, Toxicity, Fernblock, NOAEL, Photoprotectio
A Toxicological Evaluation of Germanium Sesquioxide (Organic Germanium)
A battery of OECD- and GLP-compliant toxicological studies was performed to assess the safety of a highly purified germanium sesquioxide, an organic form of the naturally occurring, nonessential trace element germanium. Germanium dioxide and germanium lactate citrate (inorganic germaniums) have been shown to induce renal toxicity, whereas germanium sesquioxide (an organic germanium) has been shown to have a more favorable safety profile. However, past toxicity studies on germanium sesquioxide compounds have not clearly stated the purity of the tested compounds. In the studies reported herein, there was no evidence of mutagenicity in a bacterial reverse mutation test or an in vitro mammalian chromosomal aberration test. There was no genotoxic activity observed in an in vivo mammalian micronucleus test at concentrations up to the limit dose of 2000 mg/kg bw/day. In a 90-day repeated-dose oral toxicity study in Han:WIST rats conducted at doses of 0, 500, 1000, and 2000 mg/kg bw/day by gavage, there were no mortalities, treatment-related adverse effects, or target organs identified. The no-observed-adverse-effect-level (NOAEL) was determined to be 2000 mg/kg bw/day
Sustainability of Forest Cover under Climate Change on the Temperate-Continental Xeric Limits
Climate change particularly threatens the xeric limits of temperate-continental forests. In Hungary, annual temperatures have increased by 1.2 °C–1.8 °C in the last 30 years and the frequency of extreme droughts has grown. With the aim to gain stand-level prospects of sustainability, we have used local forest site variables to identify and project effects of recent and expected changes of climate. We have used a climatic descriptor (FAI index) to compare trends estimated from forest datasets with climatological projections; this is likely for the first time such a comparison has been made. Four independent approaches confirmed the near-linear decline of growth and vitality with increasing hot droughts in summer, using sessile oak as model species. The correlation between droughts and the expansion of pest and disease damages was also found to be significant. Projections of expected changes of main site factors predict a dramatic rise of future drought frequency and, consequently, a substantial shift of forest climate classes, especially at low elevation. Excess water-dependent lowland forests may lose supply from groundwater, which may change vegetation cover and soil development processes. The overall change of site conditions not only causes economic losses, but also challenges long-term sustainability of forest cover at the xeric limits