První český mezioborový výzkumný projekt zaměřený na studium odledněných oblastí na pobřeží Antarktidy začal v roce 1999. Studium biodiverzity a fyziologie stresu mechorostů a lišejníků probíhalo na několika ostrovech poblíž západního pobřeží Antarktického poloostrova. Nedávno vybudovaná česká výzkumná stanice na severním pobřeží ostrova Jamese Rosse je vhodnou základnou pro pokračování studia terestrických ekosystémů se zvláštním ohledem k reakci antarktické bioty na očekávanou klimatickou změnu. and The first Czech interdisciplinary research project focused on ecological study of the Antarctic coastal deglaciated areas was started in 1999. Research into biodiversity and stress physiology of mosses and lichens was realized in several islands near the western coast of Antarctic Peninsula. A new Czech research station which has been recently built on the north coast of James Ross Island could be an excellent basis for continuation of research work in terrestrial ecosystems with special regard to the response of Antarctic biota to the expected climate change.
Kromě lišejníků amechů rostou v Antarktidě idva druhy krytosemenných rostlin - Colobanthus quitensis z čeledi hvozdíkovitých (Caryophyllaceae) a metlice Deschampsia antarctica z čel. lipnicovitých (Poaceae). Proč se v teplejších oblastech Antarktidy daří dlouhodobě přežívat jen dvěma, na první pohled nijak zvláštním druhům, když v klimaticky podobných podmínkách vysoké Arktidy jich nacházíme několik set? Mají tyto dva druhy nějaké unikátní adaptace k životu v Antarktidě, nebo je to spíše otázka šťastné náhody, která přispěla k přenosu jejich semen na odloučený kontinent? and Besides lichens and bryophytes, two species of angiosperms grow in Antarctica – Colobanthus quitensis belonging to the family Caryophyllaceae and Deschampsia antarctica from the family Poaceae. Why can only these two species, without any visual specific features, survive in warmer regions of Antarctica, while in climatically similar conditions of the high Arctic several hundred such species grow? Do these two species possess some unique adaptability to life in Antarctica, or is it rather a question of chance that their seeds were transferred to this isolated continent?
Male rats received estradiol benzoate in a long acting microcrystalline suspension (1 mg/rat i.m., twice a week), methylene blue (MB) 0.5 % in the food and the combination of estradiol and MB. After three weeks, MB partially inhibited the growth response of the anterior pituitary to estradiol and it partially inhibited the increase of cAMP content in anterior pituitary. The increase of anterior pituitary cGMP content was not modified by MB, neither the ratio cAMP/cGMP in the anterior pituitary which, however, decreased after estradiol. This decrease was not modified by MB. On the other hand, the prolactin (PRL) increase in the blood after estradiol was inhibited by MB, although the prolactin content in the anterior pituitary was not. Methylene blue alone did not change blood prolactin concentration, but it unexpectedly elevated blood thyroxine levels and this effect was partially inhibited by simultaneous estradiol treatment.
Seven Gymnura altavela (Linnaeus, 1758) (Elasmobranchii, Myliobatiformes) caught off the Tunisian coast were examined for endoparasites during a three-year period (1995-1998). A phyllobothriid cestode new to science was found in the spiral intestine of all host specimens. The presence of a tetrabothridiate scolex, bothridia lacking an apical sucker, laciniate strobila, and possession of postvaginal testes are sufficient to place this species in the genus Anthobothrium Van Beneden, 1850. In this genus, we consider that only two species, both previously reported from carcharhiniform sharks, are valid: Anthobothrium cornucopia Van Beneden, 1850 and A. laciniatum Linton, 1890. Anthobothrium altavelae sp. n. can be distinguished from its congeners by its length, strobila morphology, and the number of testes. The taxonomic position of the species attributed to Anthobothrium parasitic in gymnurids is discussed.
Anthocyanins and nonphotochemical quenching (NPQ) are two important tools that provide photoprotection in plant leaves. In order to understand how plants use these tools for acclimation to changing seasonal conditions, we investigated pigments, antioxidative capacity, and photosynthesis in leaves of an evergreen tree (Acmena acuminatissima) in two contrasting seasons. Young leaves of A. acuminatissima appeared in distinct colors, being light green in summer and red in winter due to the presence of anthocyanins. In the winter young leaves, anthocyanins contributed less than 2% to the antioxidant pool. In the summer, young leaves had higher NPQ than that of mature leaves, but in the winter, they did not derive any NPQ-related advantage over mature leaves. These results suggest that the accumulation of anthocyanins in young leaves in the winter may compensate for the insufficient photoprotection afforded by NPQ and that anthocyanins function as a light attenuator to protect the photochemical apparatus against excess light., H. Zhu, T.-J. Zhang, J. Zheng, X.-D. Huang, Z.-C. Yu, C.-L. Peng, W. S. Chow., and Obsahuje bibliografické odkazy
In our previous studies, a decreased blood pressure was reported in children treated by anthracycline (AC). The aim of this study was to assess the long-term effects of AC anticancer therapy in 45 subjects aged 13-22 years by repeated 24-hour Holter monitoring of blood pressure. Sixty four aged-matched subjects served as controls. The differences between mean values of systolic (SBP) and diastolic blood pressure (DBP) in each hour of both groups were evaluated by Mann-Whitney test. Also the parameters of the least-squares fit of the sinusoidal curve in each subject were estimated (M - mesor, midline-estimating, a mean value of sinusoidal curve corresponds to 24-hours mean pressure; A - amplitude, double amplitude corresponds to nightday difference; Acr - acrophase is a time of maximal value of a sinusoidal curve). SBP and DBP was significantly lower only during night hours in anthracycline patients 19-22 years old. Also M was lower in this age subgroup of patients comparing to age matched controls (SBP: 112±6 mm Hg versus 117±7 mm Hg, p<0.05; DBP: 67±3 mm Hg versus 69±6 mm Hg, p<0.05), A was not different, Acr in patients was shifted one hour earlier (SBP: 2.4 p.m. versus 3.6 p.m., p<0.05; DBP: 2.1 p.m. versus 3.3 p.m., p<0.01). This corresponds to the shift of the morning blood-pressure increase seen on 24-hours blood pressure profiles. M correlated with age in controls (SBP: r=0.374, p<0.01; regression coefficient b=1.34 mm Hg/1 year; DBP: r=0.365, p<0.01; b=0.95 mm Hg/1 year), but not in patients (SBP: r=0.182, DBP: r=0.064). A and Acr were age-independent in all subjects. It is concluded that blood pressure in 19-22 years old AC patients is lower during night hours, the age-dependent increase of blood pressure seen in healthy controls between 13 and 22 years of age does not occur in patients. This finding is consistent with the long-lasting impairment of the sympathetic nervous system caused by anthracyclines., Z. Nováková ... [et al.]., and Obsahuje bibliografii a bibliografické odkazy
From the year 2000, the environmental state and the impact of human activities on fluvial lakes in the central part of the Czech section of the Elbe River is evaluated. For that reason, three oxbow lakes were chosen: Lake Labiště pod Opočínkem (east of Pardubice), Lake Doleháj (near Kolín), and Lake Obříství (near Mělník). All of them are situated within an area with a well-developed chemical industry and the nearby lowlands are one of the most intensively farmed areas of the Czech Republic. In spite of the identical origin during the river canalization, major differences were found. E.g. very low oxygen saturation in Opočínek (mean saturation 46 %) was determined. Nutrient concentrations and their seasonal dynamics (nitrites, nitrates, ammoniated ions, and phosphates) differed in each lake as well. The lowest concentrations of heavy metals (Ag, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb and Zn) in sediment were found in the Doleháj. In samples from Obříství after a big flood in September 2002, the Index of Geoaccumulation increased only for Pb and decreased for Hg. This result indicated that the pollution has probably not been occurred during such floods. and Od roku 2000 jsou v oblasti středního Labe hodnoceny přírodní podmínky starých labských ramen a posuzován vliv antropogenní činnosti na ně. Z toho důvodu byly pro výzkum vybrány následující tři slepé opuštěné meandry: Labiště pod Opočínkem (východně od Pardubic), Doleháj (v blízkosti Kolína) a jezero Obříství (v blízkosti Mělníka). Všechna tato fluviální jezera leží v oblasti s velmi rozvinutým chemickým průmyslem, přilehlé nížiny jsou též jedny z nejintenzivněji obdělávaných zemědělských ploch v České republice. Ačkoliv jezera vznikla stejným způsobem při regulacích řeky, byly mezi nimi zjištěny značné rozdíly. Například lokalita Opočínek vykazovala značně nízké hodnoty nasycení vody kyslíkem (průměrné nasycení 46 %). Koncentrace živin a jejich sezónní dynamika (dusitany, dusičnany, amonné ionty a fosforečnany) se též v každém případě lišila. Nejnižší koncentrace těžkých kovů (Ag, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb a Zn) v sedimentu byly zaznamenány v Doleháji. Ve vzorcích z lokality Obříství po velké povodni v roce 2002 se zvýšil geoakumulační index jen v případě Pb, naopak hodnota u Hg poklesla. Výsledky proukázaly nepřítomnost výrazného znečištění po této povodni.
The aim of our study was to evaluate antibodies against thyroglobulin (anti-TG) and thyroid peroxidase (anti-TPO) – markers of autoimmune thyroiditis – in several groups of adult patients with type 1 and type 2 diabetes mellitus (DM). We were particularly interested whether the presence of thyroid antibodies is related to the positivity of glutamic acid decarboxylase antibodies (anti-GAD). We found elevated anti-GAD in 46 % (97/210) patients with type 1 DM. All patients with type 2 diabetes were anti-GAD-negative. At least one thyroid antibody (anti-TG and/or anti-TPO) was found in 30 % (62/210) patients with type 1 DM and 27 % (22/83) type 2 diabetes patients. The patients with type 1 DM were further grouped according to their anti-GAD status. The anti-GAD-positive patients had a higher prevalence of anti-TG antibodies than the anti-GAD-negative patients (25 % vs. 12 %, p=0.03) as well as anti-TPO antibodies (32 % vs. 12 %, p<0.001). At least one thyroid antibody was detected in 39 % (38/97) of anti-GAD-positive but only in 21 % (24/113) of anti-GAD-negative patients with type 1 DM (p=0.006). No significant difference in the frequency of thyroid antibodies was found between anti-GAD-negative patients with type 1 and type 2 DM (21 % vs. 27 %, p=0.4). The groups with or without thyroid antibodies in both type 1 and type 2 diabetic patients did not differ in actual age, the age at diabetes onset, duration of diabetes, body mass index or HbA1c level. Patients with elevated thyroid antibodies had significantly higher levels of TSH than those without thyroid antibodies (1.86 vs. 3.22 mIU/l, p=0.04 in type 1 DM; 2.06 vs. 4.89 mIU/l, p=0.003 in type 2 DM). We conclude that there is a higher frequency of thyroid-specific antibodies in anti-GAD-positive adult patients with type 1 DM than in anti-GAD-negative patients or in patients with type 2 DM. Patients with or without thyroid antibodies do not differ in age, DM onset and duration, BMI or HbA1c. Thyroid antibodies-positive patients have higher levels of thyroid stimulating hormone (TSH).