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A Tretyn

Publications and source records attributed to A Tretyn.

8 recordsLinked to original sources
PubMed2006

Etiology of inguinal hernia: ultrastructure of rectus sheath revisited.

In the last decade, in the search for abdominal-wall hernia etiology, attention has been brought to alterations in the connective tissue ultrastructure as the probable etiological factor. These may cause weakening of connective tissue, which in turn may form ground for hernia formation. To investigate this hypothesis in depth, we compared the ultrastructure of the connective tissue in hernia patients and the control group. The study group consisted of five patients with primary inguinal hernia (Nyhus II = 4, Nyhus IIIa = 1). Another five patients posted for emergency appendectomy created the control group. Tissue specimens, harvested intraoperatively from the rectus muscle sheath (RAMS) and fixed in 4% glutaraldehyde, underwent staining by the Masson, H-E and methylene blue techniques and were assessed by microscopy (light and scanning electron). The examinations showed significant differences in the rectus sheath ultrastructure. They included altered architecture, placement and quantity of collagen and elastic fibers, differences in the caliber of individual fibers and disrupted ground matter-to-fiber ratio. In patients with hernias, chaotic arrangement of collagen fibers was seen, as well as their thinning and a decrease in the general amount of elastic fibers, replaced by ground matter. Our research has shown significant differences in the structure of the RAMS between patients with hernias and healthy individuals. This supports the theory linking connective tissue alterations with the etiology of hernia, and stating that these alterations include connective tissue at locations distant from the hernia site as well, as the rectus sheath itself does not form a hernial defect.

Adolescent↗
PubMed1997

Loading and localization of Fluo-3 and Fluo-3/AM calcium indicators in sinapis alba root tissue.

Stimulus-induced changes in free cytosolic Ca2+ in different types of plant cells have been monitored with the aid of fluorescent calcium indicator dyes. However, there is no simple and convenient method for introducing these dyes into the plant cell cytoplasm. This paper reports tests of different procedures for loading either free fluorescent dyes or their acetoxymethyl esters (Fluo-3 and Fluo-3/AM, respectively) into Sinapis alba root tissue. Loading of Fluo-3 was pH and temperature dependent. Moreover, in the presence of beta-escin (saponin) in the loading medium very high fluorescent signals in root tissues were observed. The highest signals were recorded when tissue was loaded in a medium containing 0.1% beta-escin, at pH 5.0 and 30 degrees C. Only very weak fluorescence signals were found in mustard roots loaded with Fluo-3/AM. Acidity and temperature of the medium had no significant effect on the process. However, addition of eserine, a cholinesterase inhibitor led to a dramatic increase in fluorescence in the root cells. On the basis of these observations rapid and efficient methods of loading both Fluo-3 and Fluo-3/AM into mustard root tissues are proposed.

Acetylcholinesterase↗
PubMed1996

Selective binding of Ca2+, Zn2+, Cu2+ and K+ by the physodes of the green alga Mougeotia scalaris.

Cells of the zygnematophycean green alga Mougeotia contain numerous globules with polyphenolic matrix, which resemble physodes. In order to analyse the capability of this compartment to sequester various ions, trichomes of Mougeotia scalaris were either fixed for X-ray microanalysis simultaneously in 2% glutardialdehyde/1% OsO4 in phosphate buffers of different K+/Na(+)-ratios, or embedded directly (fresh material) in Nanoplast resin. In addition, fixed material was treated with potassium antimonate and Ca2+ localization was examined by electron microscopic cytochemistry. A Ca(2+)-depletion upon fixation at different K+/Na(+)-ratios resulted in selective uptake of potassium, but not sodium. Consistent with earlier findings, calcium-binding by the polyphenolic physode matrix does not depend merely on electric charge but also on the presence of protonated/deprotonated phenolic groups, together with ester-linked carbonyl oxygen, which seem to be good candidates for a co-ordinate type of calcium-binding. Nanoplast embedding turned out to be the most adequate and fastest preparation for X-ray microanalysis and, apart from retaining calcium, allowed the detection of zinc and copper inside the physodes.

Calcium↗
PubMed1992

Electron microscopic characterization of calcium-binding physodes in the green alga Mougeotia scalaris.

Effect of the covalently cross-linking agents glutardialdehyde and osmium tetroxide, and of adsorption of the vital dye, neutral red, to the matrix of the calcium-binding "vesicles" from the green alga Mougeotia scalaris has been analysed in situ, both in terms of structural preservation and of the calcium-binding capacity of the vesicles. Upon cell fixation in glutardialdehyde without OsO4, the vesicles appear to dissolve, but upon simultaneous fixation in glutardialdehyde with OsO4 (1% w/v), the vesicles retain a globular form, are evenly stained by osmium and appear to be surrounded by a membrane-like structure. This structure was also observed around the vesicles in cells preincubated for 10 min in 0.1 mM neutral red and then fixed in glutardialdehyde/OsO4 for 1 h. More detailed information of the matrix structure is obtained when simultaneous fixation of the Mougeotia cells was shortened to 15 min: a membrane-like structure was no longer observed around the vesicles. After cell treatment in the presence of neutral red, no calcium at all was found inside the vesicles. A small amount of calcium remained, when cells were fixed simultaneously and extensively in the absence of neutral red. However, calcium was found, to a considerable extent, inside the vesicles after short simultaneous fixation of the cells in the absence of neutral red. Based on the ultrastructural and elemental features presented here, the calcium-binding vesicles in Mougeotia appear to represent a member of the large family of (calcium-binding) physodes in lower plants (CaBP).

Calcium↗
PubMedDate not supplied

Calcium-dependent signal transduction pathways in plants--phytochrome mechanism of action as an example.

Higher plants appear to have some signalling molecules that are similar to those in animals. Early events in the response of plant cell to many physiological stimuli share common features, such as membrane depolarization and elevation in cytosolic free calcium level. Ca2+ has a vital role in mediating plant responses to external stimuli of both abiotic origin (e.g. light, cold, heat, movement, hypoxia and drought) and biotic origin (e.g. phytohormones, pathogens, interaction with symbionts). Recently, tremendous progress has been made in understanding the role of Ca2+ as a second messenger in plants. It has been shown that plasma membrane Ca2+ channels and vacuolar Ca2+ release channels may participate in multiple signalling pathways in higher plants. Ca(2+)-dependent modulation of cellular processes occurs via intracellular calcium-binding proteins, of which calmodulin is one of the best characterized. It is well documented that calcium is involved in light-induced, phytochrome-controlled signal transduction pathways in higher plants.

Calcium↗
PubMedDate not supplied

Oscillations of acetylcholine in oat seedlings.

Using gas chromatography it was shown that acetylcholine (ACh) was present in both etiolated and green oat (Avena sativa L. cv. Diadem) seedlings. In etiolated seedlings the ACh level was low, but increased rapidly during exposure to sunlight and red light (RL). The stimulative influence of RL was reversed by far-red light (FRL). The RL- and FRL- changes in ACh level were correlated to changes in acetylcholinesterase (AChE) localization. Using Karnovsky's method, it was found that in the etiolated coleoptiles the products of enzymatic reaction showing AChE activity accumulated selectively on the external side of plasma membrane. After exposure of seedlings to RL AChE activity disappeared. Subsequent FRL made it reappear on the external side of the plasma membrane. When the plants became green, oscillations of ACh were clearly observable. For plants grown under a LD 16:8 cycle the changes were circadian.

Acetylcholine↗