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61.
Dilek Gogas Yavuz Belgin Kü?ükkaya H. ?nder Ers?z A. Süha Yal?in Kaya Emerk Sema Akalin 《Experimental diabetes research》2002,3(2):145-151
Nonenzymatic glycation of tissue and plasma
proteins may stimulate the production of oxidant
and carbonyl stress in diabetes. The aim
of this study was to evaluate the effects of
aminoguanidine (AG) on lipid peroxidation,
protein oxidation and nitric oxide (NO) release
in diabetic rat kidneys. After induction of diabetes
with streptozotocin, female Wistar rats
were divided into 2 groups. Group DAG (n=9)
rats were given AG hydrogen carbonate (1 g/L)
in drinking water and group D (n=8) was diabetic
control rats given only tap water. Group
H (n=8) was followed as healthy controls. At
the end of an 8 week period, NO release, lipid
and protein oxidation were determined in kidney
tissues. NO release was significantly lower
in diabetic rats compared with healthy controls
(p<0.05). Lipid peroxidation was significantly
high in group D (3.9 ± 0.3 nmol MDA/g tissue)
compared with the group DAG (2.6 ± 0.1 nmol
MDA/g tissue, p<0.01) and group H (2.4 ± 0.2
nmol MDA/g tissue). Protein oxidation was
significantly higher in diabetics than healthy
controls (563.8 ± 23.9, 655.8 ± 7.2 , 431.5 ±
8.8 mmol carbonyl / g tissue for group DAG, D
and H, respectively, p< 0.05). A positive correlation
between albuminuria and thiobarbituric
acid reactive substance (TBARS) levels (r= 0.54,p<0.005) and carbonyl content (r=0.70,
p<0.0005) in kidney homogenate were
observed.
Although AG treatment had no effect on NO
release, it significantly decreased lipid peroxidation
in diabetic rat cortices. Consequently
increased lipid peroxidation -as well as- protein
oxidation could be involved in the pathogenesis
of diabetic albuminuria. 相似文献
62.
63.
Nucleolar development in the cleaving chick germ up to the formation of the primary hypoblast was followed through a series of well-defined uterine and early incubated stages both by light and electron microscopy. Well-established criteria of nucleolar morphology were used for determining the developmental stage of onset of rRNA synthesis. By these criteria rRNA synthesis was first observed at midcleavage in uterine stage VII [1] germs. This could be correlated with the first morphogenetic event—the posterio-anteriorly orientated formation of the area pellucida which results in a bilaterally symmetrical blastoderm. 相似文献
64.
The buffering capacity inside thylakoids is determined and the magnitude of flash-induced pH changes inside is calibrated in the pH range from 6.4 to 8.1. The work is based on flash-induced absorption changes of neutral red in a chloroplast suspension in which the outer phase is strongly buffered by bovine serum albumin. It is shown that neutral red is bound inside thylakoids. The binding can be described by a simple isotherm with an apparent Km = 4 μM and saturation at 1 neutral red per 17 chlorophylls. The apparent pK of neutral red is shifted from 6.6 in solution to 7.25 when bound inside. It is demonstrated that neutral red is a clean indicator of pH changes inside, i.e. when properly used it shows no response to other events. Although bound it reports pH changes which occur in the internal osmolar (aqueous) volume of thylakoids. This is obvious from the influence of chemically very different buffers on the magnitude of the absorption changes of neutral red. These act in a manner proportional to their calculated buffering capacity in aqueous solution. The intrinsic buffering capacity of the internal phase is determined with the aid of these buffers, at pH 7.2 it is between 0.8 and 1 mM (at 60 mosM). The absence of large variations in the buffering capacity in the range from pH 6.4 to 8.1 suggests that proteinaceous groups are involved in addition to the lipids which may dominate the buffering capacity at lower pH. The magnitude of the internal pH change is approx. 0.6 (at pH 7.3) under stimulation of both photosystems with a short xenon flash of light. 相似文献
65.
66.
A package of methods and an experimental set-up for the analysis of dynamics of electrical signals from the brain. The methods described and discussed in this study allow detailed and multipurpose analysis of brain potentials both in the time and frequency domains. Special emphasis is given to a new computer-method introduced in this study: A posteriori selective averaging. The selective averaging method is compared with Wiener Filter Estimation of Evoked Potentials. 相似文献
67.
Jasper Stevens Dirk-Jan van den Berg Sanne de Ridder Harm A.G. Niederländer Piet Hein van der Graaf Meindert Danhof Elizabeth C.M. de Lange 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》2010,878(13-14):969-975
Remoxipride is a selective dopamine D2 receptor antagonist, and useful as a model compound in mechanism-based pharmacological investigations. To that end, studies in small animals with serial sampling over time are needed. For these small volume samples currently no suitable analytical methods are available. We propose analytical methods for the detection of low concentrations remoxipride in small sample volumes of plasma, brain homogenate, and brain microdialysate, using online solid phase extraction with liquid chromatography–tandem mass spectrometry. Method development, optimization and validation are described in terms of calibration curves, extraction yield, lower limit of quantification (LLOQ), precision, accuracy, inter-day- and intra-day variability. The 20 μl plasma samples showed an extraction yield of 76%, with a LLOQ of 0.5 ng/ml. For 0.6 ml brain homogenate samples the extraction yield was 45%, with a LLOQ of 1.8 ng/ml. The 20 μl brain microdialysate samples, without pre-treatment, had a LLOQ of 0.25 ng/ml. The precision and accuracy were well within the acceptable 15% range. Considering the small sample volumes, the high sensitivity and good reproducibility, the analytical methods are suitable for analyzing small sample volumes with low remoxipride concentrations. 相似文献
68.
Horstmar Holländer 《Histochemistry and cell biology》1964,3(5):387-395
Zusammenfassung Es werden zwei Methoden zum histochemischen Nachweis von Schwefelsäureestern mitgeteilt, die beide auf der Verwendung von Trypaflavin beruhen. Einmal wird der Farbstoff als einfaches Fluorochrom verwendet, die Schwefelsäureester sind dabei durch ihre orange-gelbe Fluoreszenzmetachromasie erkennbar (Methode I). Das andere Verfahren bietet die Möglichkeit, das bereits angelagerte Fluorochrom mit p-Dimethylaminobenzaldehyd zu einem rot gefärbtem Komplex umzusetzen (Methode II). Färbungsvorgang, Spezifität und Haltbarkeit wurden näher untersucht.Anwendung zum Nachweis von Cerebrosidsch wefelsäureester-Ablagerungen, Mastzellengranula und, nach vorausgegangener Sulfatierung, zur elektiven Pilzdarstellung.Mit 11 Textabbildungen, davon 5 farbigen 相似文献
69.
Ikju?ParkEmail author Sanford?D.?Eigenbrode Stephen?P.?Cook Bradley?L.?Harmon Hariet?L.?Hinz Urs?Schaffner Mark?Schwarzl?nder 《BioControl》2018,63(3):377-389
In weed biological control programs, pre-release host-specificity testing relies traditionally on no-choice and choice feeding, oviposition, and development tests. Rarely have they included detailed examination of behavioral responses to olfactory and visual cues of biological control candidates, although a better understanding of the mechanisms underlying host recognition may explain potential discrepancies between choice and no-choice tests, and/or between tests conducted in the lab versus field conditions. We investigated how the seed-feeding weevil, Mogulones borraginis, distinguishes its host plant, Cynoglossum officinale, from three native confamilial non-target species in North America. In behavioral bioassays, M. borraginis responded to olfactory and visual cues individually and, to an even greater extent, to both plant cue modalities when offered simultaneously. In tests with the combined cues, M. borraginis was attracted to C. officinale but responded with indifference or was repelled by non-target plants. In electrophysiological experiments, we identified that M. borraginis responded to ten volatile compounds and four wavelengths of lights from inflorescences of C. officinale. We propose that studies of responses to multimodal plant cues can advance our understanding of how biocontrol candidate species discriminate among host plants and closely related non-target species, thereby increasing the accuracy of environmental safety assessments pre-release. 相似文献
70.
S Gründer D Firsov S S Chang N F Jaeger I Gautschi L Schild R P Lifton B C Rossier 《The EMBO journal》1997,16(5):899-907
Pseudohypoaldosteronism type 1 (PHA-1) is an inherited disease characterized by severe neonatal salt-wasting and caused by mutations in subunits of the amiloride-sensitive epithelial sodium channel (ENaC). A missense mutation (G37S) of the human ENaC beta subunit that causes loss of ENaC function and PHA-1 replaces a glycine that is conserved in the N-terminus of all members of the ENaC gene family. We now report an investigation of the mechanism of channel inactivation by this mutation. Homologous mutations, introduced into alpha, beta or gamma subunits, all significantly reduce macroscopic sodium channel currents recorded in Xenopus laevis oocytes. Quantitative determination of the number of channel molecules present at the cell surface showed no significant differences in surface expression of mutant compared with wild-type channels. Single channel conductances and ion selectivities of the mutant channels were identical to that of wild-type. These results suggest that the decrease in macroscopic Na currents is due to a decrease in channel open probability (P(o)), suggesting that mutations of a conserved glycine in the N-terminus of ENaC subunits change ENaC channel gating, which would explain the disease pathophysiology. Single channel recordings of channels containing the mutant alpha subunit (alphaG95S) directly demonstrate a striking reduction in P(o). We propose that this mutation favors a gating mode characterized by short-open and long-closed times. We suggest that determination of the gating mode of ENaC is a key regulator of channel activity. 相似文献