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Cytochemical Reaction (cytochemical + reaction)

Distribution by Scientific Domains

Medical Sciences	80%

Selected Abstracts

Computerized analysis of cytochemical reactions for dehydrogenases and oxygraphic studies as methods to evaluate the function of the mitochondrial sheath in rat spermatozoa

ANDROLOGIA, Issue 1 2001
M. Piasecka
Cytochemical reactions for mitochondrial NADH-dependent dehydrogenases (diaphorase/NADH which is related to flavoprotein), NAD-dependent dehydrogenases (isocitrate, malate) and succinate dehydrogenase were carried out in rat spermatozoa. In addition to a morphological evaluation, the intensity of the reactions was assessed using a computer image analysing system (Quantimet 600 S). The intensity of the reactions was examined in sperm midpieces by measuring integrated optical density (IOD) and mean optical density (MOD). The activity of mitochondrial respiratory chain complexes was also analysed using the polarographic method. In the population of spermatozoa studied, all whole spermatozoa midpieces were completely filled with formazans, the product of the cytochemical reaction. These morphological findings corresponded to the values obtained for IOD and MOD for the given enzymes. In the oxygraphic studies, the spermatozoa demonstrated consumption of oxygen in the presence of substrates for I, II and IV complexes and their mitochondria revealed normal integrity and sensitivity to the substrates and inhibitors. However, the oxygraphic studies revealed differences between the sperm and somatic cells. These differences concerned the stimulation of pyruvate oxidation by malate, the lack of an effect of malonic acid on phenazine methosulphate (an acceptor of electrons) oxidation and the lack of an effect of cytochrome c on ascorbate oxidation. The cytochemical method, together with densitometric measurements, enables: (1) the reaction intensity to be determined objectively; (2) subtle and dramatic differences in reaction intensity to be revealed between spermatozoa that do not differ under morphological evaluation of the intensity; (3) possible defects within the mitochondrial sheath to be located and assessed in a large number of spermatozoa. This method can be used as a screening method alongside the routine morphological examination of spermatozoa. On the other hand, the oxygraphic method in the inner membrane of mitochondria can reveal functional changes which are related to the action of respiratory chain complexes and display characteristic features of mitochondria energy metabolism. The methods used are complementary and allow the complex evaluation of mitochondria in spermatozoa. Both methods can be used in experimental and clinical studies. [source]

Localization of sphingomyelin during the development of dorsal and tail epidermis of mice

BRITISH JOURNAL OF DERMATOLOGY, Issue 5 2001
Y. Yoshida
Background The water permeability barrier of the stratum corneum seems to be regulated primarily by lamellar bodies situated between the corneocytes; the lamellar bodies originate largely from polar lipid precursors, mainly sphingomyelin (SM), provided by the cells of the stratum granulosum via exocytosis of their lamellar body content. Objectives The aim of our study was to evaluate the cellular distribution of SM during development of the epidermis. Methods In this study, we investigated the expression and localization of SM in both adult and fetal mouse skin by a cytochemical detection method, immunofluorescence microscopy and immunoelectron microscopy, using anti-SM antibody, a specific binding protein to SM (lysenin), and Nile red stain. In addition, we measured transepidermal water loss to estimate the barrier function of the fetal skin. Results We observed that SM was widely distributed from the basal layer to the granular layer in the adult mouse epidermis. An intense cytochemical reaction for SM was observed on embryonic day E14·5 of gestation just before the differentiation of the granular and squamous cells from the intermediate cells. The immunofluorescence indicating SM was detected in two regions, i.e. the most superficial zone of the granular layer and the upper spinous layer after the cell differentiation at the late gestational age. This distribution was not detected by conventional lipid staining, such as with Nile red stain. Immunoelectron microscopy revealed that SM was mainly localized in the intercellular spaces of the adult mouse epidermis and in the intracellular vesicles without a complete lamellar structure in the cytoplasm of epidermal cells of E14·5 fetuses. It is well known that the formation of the structurally mature cornified cell envelope occurs at E15·5 of development. The skin of fetuses at E16·5 showed a definite barrier function. Conclusions These findings suggest that SM dynamics is related to the formation of the lipid envelope, cell differentiation, and epidermal barrier function during development. [source]

Effectiveness of Four New Pyrazole-pyrimidines on Phytopathogens: Ultrastructural Evidences on Pythium ultimum

JOURNAL OF PHYTOPATHOLOGY, Issue 7-8 2000
D. Mares
Four newly synthesized molecules derived from pyrazole-pyrimidine were assayed on Botrytis cinerea Micheli, Fusarium moniliforme Sheld and Pythium ultimum Trow. All proved effective in inhibiting the growth of the phytopathogens at all of the test concentrations (10, 20, 50, 100 ,g/ml). The most effective compound was 1-(3)nitrophenyl - 6 - trifluoromethylpyrazolo[3,4 - d]pyrimidine 4(5H)-thione (CF33). Ultrastructural studies on P. ultimum treated with CF33 revealed alterations in the normal hyphal shape and, at high concentration, plasmolysis and damage to the wall texture was observed. At 20 ,g/ml different vesicles were seen in the cytoplasm: some appeared quite dense, and specific cytochemical reactions indicated that they were most likely peroxysomes; other vesicles seem to be vacuoles of varying content. In some cases there was disintegration of the nuclear envelope. The effects on membrane lipids and interference in protein synthesis are hypothesized as possible mechanism of action of the molecule. Zusammenfassung Vier neu synthetisierte Pyrazol-Pyrimidin-Derivate wurden an Botrytis cinerea Micheli, Fusarium moniliforme Sheld und Pythium ultimum Trow. geprüft. Alle hemmten das Wachstum der Phytopathogene in allen Testkonzentrationen (10, 20, 50 und 100 ,g/ml). Die wirksamste Verbindung war 1-(3)Nitrophenyl-6-trifluormethylpyrazolo[3,4-d]pyrimidin-4(5H)-thion (CF33). Feinstrukturelle Untersuchungen an mit CF33 behandeltem P. ultimum zeigten Veränderungen in der normalen Hyphenform, bei hohen Konzentrationen wurden zudem Plasmolyse und Schäden der Wandstruktur beobachtet. Bei 20 ,g/ml waren verschiedene Vesikel im Cytoplasma zu sehen. Einige von diesen waren recht dicht, und spezifische cytochemische Reaktionen ergaben, dai es sich höchstwahrscheinlich um Peroxisomen handelte. Andere Vesikel waren offenbar Vakuolen unterschiedlichen Inhalts. In einigen Fällen kam es zur Auflösung der Kernmembran. Als mögliche Wirkungsmechanismen des Moleküls werden die Wirkungen auf die Membranlipide und der Eingriff in die Proteinsynthese angesehen. [source]

Computerized analysis of cytochemical reactions for dehydrogenases and oxygraphic studies as methods to evaluate the function of the mitochondrial sheath in rat spermatozoa