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261.
Maria Kovalska Barbara Tothova Libusa Kovalska Zuzana Tatarkova Dagmar Kalenska Anna Tomascova Marian Adamkov Jan Lehotsky 《Neurochemical research》2018,43(9):1766-1778
Alzheimer’s disease (AD) is a progressive and irreversible neurodegenerative disorder that results in massive hippocampal and neocortical neuronal loss leading to dementia and eventual death. The exact cause of Alzheimer’s disease is not fully explored, although a number of risk factors have been recognized, including high plasma concentration of homocysteine (Hcy). Hyperhomocysteinemia (hHcy) is considered a strong, independent risk factor for stroke and dementia. However, the molecular background underlying these mechanisms linked with hHcy and ischemic stroke is not fully understood. Paper describes rat model of global forebrain ischemia combined with the experimentally induced hHcy. Global ischemia-reperfusion injury (IRI) was developed by 4-vessels occlusion lasting for 15 min followed by reperfusion period of 72 h. hHcy was induced by subcutaneous injection of 0.45 µmol/g of Hcy in duration of 14 days. The results showed remarkable neural cell death induced by hHcy in the brain cortex and neurodegeneration is further aggravated by global IRI. We demonstrated degeneration of cortical neurons, alterations in number and morphology of tissue astrocytes and dysregulation of oxidative balance with increased membrane protein oxidation. Complementary to, an immunohistochemical analysis of tau protein and β-amyloid peptide showed that combination of hHcy with the IRI might lead to the progression of AD-like pathological features. Conclusively, these findings suggest that combination of risk factor hHcy with IRI aggravates neurodegeneration processes and leads to development of AD-like pathology in cerebral cortex. 相似文献
262.
Vladimir Vincek Dagmar Klein Robert T. Graser Felipe Figueroa Colm O'hUigin Jan Klein 《Immunogenetics》1995,42(4):262-267
The only avian major histocompatibility complex (Mhc) genes thus far identified are from species of the relatively small order of Galliformes, while by far the largest order of Passeriformes (songbirds), containing some 60% of extant bird species, has not been studied at all in this regard. The Galliformes emerged more than 55 million years (my) ago, the Passeriformes some 25 my ago. Because of the potential for the use of Mhc genes as markers in the study of songbird populations, an attempt was made to clone class II B genes of a passeriform species, the Bangalese finch Lonchura striata acuticauda. Using a set of primers designed on the basis of known sequences, a probe corresponding to part of exon II was obtained by the polymerase chain reaction. The probe was then used to screen a Bengalese finch cDNA library and to isolate and sequence two nearly full-length clones. The sequences reveal the presence of one presumably functional class II B locus in this bird species. 相似文献
263.
Dagmar Barthel 《Polar Biology》1996,17(1):91-94
During the CS-EASIZ expedition (ANT XII/3) to the eastern Weddell Sea shelf with RF ‘Polarstern’ in January–March 1996, several
hundred hexactinellids from trawl catches were inspected for associated fauna. At one station, fish egg masses were found
in the suboscular cavities of 18 specimens of hexactinellid sponges belonging to four different species of the genus Rossella. Egg numbers in intact hexactinellids ranged from about 800 to more than 8000. At two stations, pentacrinoids, the sessile
stage of comatulid crinoid development were found attached to the inner dermal membrane of hexactinellids. This is the first
time pentacrinoids have been documented from the high Antarctic. The pentacrinoids mostly formed small groups, but single
individuals were found as well. Neither fish eggs nor pentacrinoids were observed in or on other structures or animals; these
findings stress the overall importance of sponges, especially hexactinellids, as substrates for developmental stages of other
members of the ecosystem.
Received: 25 May 1996/Accepted: 22 July 1996 相似文献
264.
Dagmar Vogel Horst Bleckmann 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1997,180(6):671-681
The surface-feeding fish Aplocheilus lineatus uses its cephalic lateral line to detect water surface waves caused by prey insects. The ability of Aplocheilus to discriminate between surface waves with aid of the lateral line system was tested by go/no-go conditioning. Our results
show that Aplocheilus can distinguish between single-frequency surface wave stimuli with equal velocity or equal acceleration amplitudes which
differ only in frequency. Frequency difference limens were about 15%, i.e. fish distinguished a 20-Hz wave stimulus from a
23-Hz stimulus in 100% of the trials. Aplocheilus can also discriminate between pure sine-wave stimuli and sine waves which show abrupt frequency changes. In contrast, fish
were unable to distinguish amplitude-modulated wave stimuli (carrier frequency 20, 40 and 60 Hz, modulation frequency 10 and
20 Hz) from pure sine waves of the same frequency, even if amplitude modulation depth was 80%.
Accepted: 27 December 1996 相似文献
265.
Bohuslav Melichar Dagmar Solichová Iveta Svobodová Karolina Melicharová 《Luminescence》2005,20(4-5):311-314
Inhalational administration of interleukin-2 (IL-2) is effective in controlling renal cell carcinoma (RCC) lung metastases with minimal toxicity. Neopterin is an indicator of systemic immune activation in metastatic cancer and is increased after systemic IL-2 administration. Urinary neopterin was investigated in 13 patients with metastatic RCC and 18 controls. In seven patients, urinary neopterin was followed before and after treatment with inhalational IL-2. Neopterin was measured by high-performance liquid chromatography and creatinine was determined by Jaffé reaction. Urinary neopterin was significantly increased in patients with metastatic RCC compared to controls (257 +/- 263 micromol/mol creatinine vs. 110 +/- 41 micromol/mol creatinine; Mann-Whitney U-test, p < 0.05). Median survival was significantly longer in patients with urinary neopterin <173 micromol/mol creatinine compared to patients with neopterin > or = 173 micromol/mol creatinine (698 vs. 245 days; log-rank test, p < 0.05). No significant increase was observed after inhalational IL-2 therapy (147 +/- 101 vs. 153 +/- 54 micromol/mol creatinine). We conclude that urinary neopterin is increased in patients with metastatic RCC, and higher neopterin concentrations are indicative of poor prognosis. The absence of an increase in urinary neopterin after inhalational IL-2 therapy is in accord with the lack of significant systemic toxicity. 相似文献
266.
Angelo Rubino Manuel Bensi Dagmar Hainbucher Davide Zanchettin Francesca Mapelli Nives Ogrinc Davide Marchetto Sara Borin Vanessa Cardin Vesna Fajon Milena Horvat Carla Taricco Franco Baldi 《PloS one》2016,11(1)
We explore the possibility of tracing routes of dense waters toward and within the ocean abyss by the use of an extended set of observed physical and biochemical parameters. To this purpose, we employ mercury, isotopic oxygen, biopolymeric carbon and its constituents, together with indicators of microbial activity and bacterial diversity found in bottom waters of the Eastern Mediterranean. In this basin, which has been considered as a miniature global ocean, two competing sources of bottom water (one in the Adriatic and one in the Aegean seas) contribute to the ventilation of the local abyss. However, due to a recent substantial reduction of the differences in the physical characteristics of these two water masses it has become increasingly complex a water classification using the traditional approach with temperature, salinity and dissolved oxygen alone. Here, we show that an extended set of observed physical and biochemical parameters allows recognizing the existence of two different abyssal routes from the Adriatic source and one abyssal route from the Aegean source despite temperature and salinity of such two competing sources of abyssal water being virtually indistinguishable. Moreover, as the near-bottom development of exogenous bacterial communities transported by convectively-generated water masses in the abyss can provide a persistent trace of episodic events, intermittent flows like those generating abyssal waters in the Eastern Mediterranean basin may become detectable beyond the availability of concomitant measurements. 相似文献
267.
Five days of suitable continuous light induced flowering in the majority ofChenopodium murale L. ecotype 197 plants as early as at the phase of the first pair of leaves. At the time of initiation of the 2nd to 4th pairs
of leaves the capacity of plants to flower was reduced, the number of flowering plants being significantly lower under the
same inductive light treatment. The capacity to flower increased again at the phase of the 5th and the 6th pairs of leaves.
Inductive light treatment brought about a marked growth activation of organs present before induction, shoot apex elongation,
precocious formation of new leaves and activation of axillary meristems. The course of these changes in plants of different
age is demonstrated. The terminal flower developed during 5 short days following inductive light treatment. The paper shows
similarities and differences between long-daymutale L. ecotype 197 and short-day C.rubrum L. ecotype 374 grown under practically uniform conditions. 相似文献
268.
The technique of estimating gamma-aminobutyric acid (GABA) turnover by inhibiting its major degrading enzyme GABA-T (4-aminobutyrate:2-oxoglutarate aminotransferase; EC 2.6.1.19) and measuring GABA accumulation has been used repeatedly, but, at least in rats, its usefulness has been limited by several difficulties, including marked differences in the degree of GABA-T inhibition in different brain regions after systemic injection of GABA-T inhibitors. In an attempt to improve this type of approach for measuring GABA turnover, the time course of GABA-T inhibition and accumulation of GABA in 12 regions of rat brain has been studied after systemic administration of aminooxyacetic acid (AOAA), injected at various doses and with different routes of administration. A total and rapidly occurring inhibition of GABA-T in all regions was obtained with intraperitoneal injection of 100 mg/kg AOAA, whereas after lower doses, marked regional differences in the degree of GABA-T inhibition were found, thus leading to underestimation of GABA synthesis rates, e.g., in substantia nigra. The activity of the GABA-synthesizing enzyme GAD (L-glutamate-1-decarboxylase; EC 4.1.1.15) was not reduced significantly at any time after intraperitoneal injection of AOAA, except for a small decrease in olfactory bulbs. Even the highest dose of AOAA tested (100 mg/kg) was not associated with toxicity in rats, but induced motor impairment, which was obviously related to the marked GABA accumulation found with this dose. The increase in GABA concentrations induced with intraperitoneal injection of 100 mg/kg AOAA was rapid in onset, allowing one to estimate GABA turnover rates from the initial rate of GABA accumulation, i.e., during the first 30 min after AOAA injection. GABA turnover rates thus determined were correlated in a highly significant fashion with the GAD activities determined in brain regions, with highest turnover rates measured in substantia nigra, hypothalamus, olfactory bulb, and tectum. Pretreatment of rats with diazepam, 5 mg/kg i.p., 5-30 min prior to AOAA, reduced the AOAA-induced GABA accumulation in all 12 regions examined, most probably as a result of potentiation of postsynaptic GABA function. The data indicate that AOAA is a valuable tool for regional GABA turnover studies in rats, provided the GABA-T inhibitor is administered in sufficiently high doses to obtain complete inhibition of GABA degradation. 相似文献
269.
270.