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Results for “Histochemical Effects”

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At least 73 records · Page 4Linked to original sources
PubMed1995

Astrocyte transplants alleviate lesion induced memory deficits independently of cholinergic recovery.

Basal forebrain tissue fragments taken from embryonic day 15 were separated into primary astrocytes and primary neurons in culture and grafted to rats with alpha-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid lesions to the nucleus basalis and medial septal regions. The two cell types were compared in two experimental paradigms for their behavioural, biochemical and histochemical effects; standard transplants of whole basal forebrain and sham transplants served as positive and negative controls, respectively. Each transplant cell type was characterised by in vitro immunocytochemistry to assess content and purity. Memory deficits produced by the lesions in a spatial win-stay T-maze task (Experiment 1) and a spatial plus associative radial maze task (Experiment 2) were significantly improved by the astrocyte, but not by the neuronal, primary cell transplants. The astrocyte graft groups performed as well as standard cholinergic rich basal forebrain groups, reaching control levels on both tasks, while the neuronal transplant groups were not significantly different to lesioned (sham transplanted) rats. There was no recovery in choline acetyltransferase activity in brain regions containing astrocyte grafts whereas activity in the neuronal graft regions was increased (often to control levels), similar to recovery produced by basal forebrain grafts. Grafts in all groups survived, transplanted neurons displaying similar morphology and placement in the host brain to unseparated basal forebrain grafts, while astrocytes showed evidence of migration. The cultured astrocytes were estimated to be > 95% pure, showing positive staining for all astrocyte markers and an absence of staining for neuronal markers. The results indicate that the restoration of cognitive function following fetal grafting is not dependent upon a restoration of cholinergic neuronal activity but is more likely mediated via diffuse graft-host communication, with trophic secretion a probable factor. This study emphasizes the usefulness of astrocytes in the repair of central nervous system injury and has implications for therapeutic potential.

Animals↗
PubMed2004

Salt-induced antioxidant metabolism defenses in maize (Zea mays L.) seedlings.

Salinity alters general metabolic processes and enzymatic activities, causing increased production of reactive oxygen species (ROS). Expression of antioxidant defense genes would, in turn, be triggered to defend the cell against oxidative damage. We report that salt disturbed antioxidant metabolism in maize seedlings, causing detrimental effects on the growth and development of maize plantlets, increased hydrogen peroxide production and altered antioxidant activities and transcripts profiles. Excessive ROS levels were accompanied by increased catalase (CAT) activity in photosynthesizing shoots, along with induction of mRNA accumulation. Increased accumulation of superoxide dismutase (SOD) transcripts was also observed although no significant changes in total SOD enzymatic activity and isozyme profiles were detected. Higher salt concentrations (above 0.25 M NaCl) were highly detrimental to the plants, causing arrested growth and severe wilting, among other effects. Histochemical detection of H(2)O(2) by 3,3-diaminobenzidine (DAB) staining indicated a collapse of the leaf veins, with hydrogen peroxide leaking to neighboring cells. In agreement to these observations, Sod1, Sod2, Sod4, Sod4A, as well as all Cat transcripts were severely inhibited in plants exposed to high salt concentrations.

Antioxidants↗
PubMed1992

Water: mechanism of oral rehydration, water deficiency = deficiency in salt.

UNICEF, the United Nations International Children Emergency Funds, has staged an enormous program to improve children's health conditions in the developing countries. One extremely fruitful field of engagement was, and still is, the treatment of dehydration. Oral rehydration therapy (ORT) has reluctantly been accepted in the industrialized countries. From clinical observations, we have gained a new understanding of known pathophysiological principles. Dehydration most often is a result of diarrhea, and therefore oral rehydration therapy is mostly referred to in the context of infections of the digestive system. We discuss additional causes of dehydration and its immediate and secondary consequences. We demonstrate not only that, but why and how, a very simple, inexpensive regimen is beneficial and effective in the treatment of dehydration. Without consideration of sodium deficit, understanding will fail, and treatment will remain ineffective.

Adolescent↗
PubMed1981

Collagen degradation in an experimental inflammatory lesion: studies on the role of the macrophage.

Collagen degradation was investigated in experimental inflammatory lesions made by implanting fluorescein-collagen sponges into sensitised rats for four days, before transferring them into culture medium. The breakdown of the collagenous structure in vitro by invading cells was inhibited by steroids and related anti-inflammatory drugs whereas non-steroidal anti-inflammatory drugs were without effect. Inhibitors of the lysosomal proteinases were variably effective with chloroquine giving total inhibition, leupeptin and TLCK partial inhibition and aurothioglucose showing no effect. Histochemical studies were made of the distribution of cathepsin B. Beta-glucuronidase and N-acetyl-glucosaminidase in macrophages attached to a collagen substratum. Measurements with specific microelectrodes showed that the microenvironment at the surface of activated macrophages was markedly acidic with values of pH less than 5 between attached cells and collagen substratum. Such conditions would be hostile to neutral collagenases and favour acid (lysosomal) proteinases.

Acetylglucosaminidase↗
PubMed1994

3-Nitropropionic acid toxicity in cultured murine embryonal carcinoma cells.

The morphologic and histochemical effects of 3-nitropropionic acid (NPA) were examined in cultured murine embryonal carcinoma cells. NPA caused a dose-dependent inhibition of cell proliferation of cultured murine embryonal carcinoma cells at concentrations above 1.05 mM and was lethal at 4.2 mM. Morphologic changes included gross swelling of the cells, swelling of mitochondria and accumulation of organellar debris within the cytoplasm. NPA inhibited the activity of succinate dehydrogenase but not of malate, isocitrate or glucose-6-phosphate dehydrogenases, resulting in a decrease in intracellular ATP. Although succinate dehydrogenase activity was decreased by NPA, propionic acid and its mercapto-, 2-chloro-, and 3-chloro- derivates did not affect enzyme activity. 3-Nitropropanol also inhibited succinate dehydrogenase but only at a much higher concentration than was required with NPA. The results provide evidence that cytotoxicity caused by NPA results from inhibition of succinate dehydrogenase activity leading to depression of ATP synthesis. Loss of cellular integrity is probably a direct consequence of failure of energy-dependent cell homeostatic mechanisms such as the plasma membrane Na+/K+ pump, resulting in swelling and ultimately lysis of the cell.

Adenosine Triphosphate↗
PubMed1978

Effects of starvation on the oocytes of Cyprinus carpio--a cytomorphological and histochemical study.

Effects of induced starvation on the morphology of the oocytic nucleus in Cyprinus carpio have been studied to assess the nature of structural aberrations caused and the adaptations induced in the oocytes during the period of stress on account of inanition. An attempt has also been made to study the fate of a number of metabolites during this period. It has also been observed that the nuclear membrane undergoes partial or complete degeneration and there is a proliferation in the number of nucleoli which tend to move into the cytoplasm. In addition, the degenerating oocytes tend to release most of the metabolites into the interstitial tissue surrounding the oocytes.

Animals↗
PubMed1977

Histochemical and histological effects of lead on the liver and kidney of the dog.

In a series of 3 experiments, beagle dogs were dosed orally with lead carbonate and the histochemical and histological changes in the liver and kidney assessed. Dosing at 50 mg/kg per day for 5 weeks resulted in well documented histological changes in the kidney and hydropic degeneration in the liver; significant alterations in the activity of the majority of enzymes studied were also seen in both organs. In dogs dosed for one week at 50 or 100 mg/kg no histological changes were seen and histochemical alterations were mainly confined to the dehydrogenases and NADPH diaphorase. A third group of dogs were dosed for 3 weeks; during a subsequent recovery period of almost 2 months the mild clinical effects produced by lead during the dosing period were quickly reversible except in 2 dogs. At the end of the recovery period histochemical alterations were evident in both organs of these 2 dogs principally shown by a reduction in the dehydrogenases of the liver. The findings are interpreted as an effect by lead on a range of cellular enzymes particularly those involved in energy production, these effects being still demonstrable after an extended recovery period.

Animals↗
PubMedDate not supplied

Histologic and histochemical study of effects of anabolic steroids on the female larynx.

The larynges of 30 unmated, mature female albino mice were examined histologically and histochemically after injecting them with 19-nandrolone phenylpropionate. Permanent irreversible changes, in the form of parakeratosis and squamous metaplasia of the epithelium, and hypertrophy of the muscle fibers, were observed together with persistence of increased alkaline phosphatase enzyme intensity in the endothelium of capillaries and increased activity of nonspecific esterase in the muscles. Similar changes may be responsible for the alteration in the human female's voice after prolonged treatment with anabolic steroids.

Anabolic Agents↗
PubMed1978

Histochemical and ultrastructural effects of enovid E on the endometrium of the baboon.

Endometrium from a group of baboons treated with the oral contraceptive, Enovid E, was studied histologically, histochemically and ultrastructurally, and compared to endometrium from normally cycling animals. All endometria were obtained by transcervical uterine biopsy between 10 and 14 days of the treatment cycle or the normal menstrual cycle. Histologically, no discernible differences between the control and experimental endometria were apparent. While observable differences were not evident between the endometrial alkaline phosphatase and succinate dehydrogenase activities of control and experimental animals, there was an increased acid phosphatase activity in the Enovid E-treated baboon endometrium. Ultrastructurally, the glandular cells of treated animals appeared to be more physiologically advanced than did those from the control endometria. These advances were evident from the prominent Golgi complex, increased development of the endoplasmic reticulum and increases in the size, number and complexity of mitochondria. The functional correlates of these morphological and histochemical observations are discussed and compared to human endometrial studies.

Acid Phosphatase↗
PubMed2004

Cyclosporine A and adverse effects on organs: histochemical studies.

The discovery that cyclosporine A (CsA) was a powerful immunosuppressant had a significant impact on transplant medicine. Its molecular mechanism of action has been well defined in T cells and involved inhibition of critical signalling pathways that regulated T-cell activation. In fact, CsA inhibited calcineurin phosphatase activity and thereby activation of the transcription factor nuclear factor of activated T cells. Over 10 years, its use is limited by side effects, determining nephro- and hepatotoxicity, gingival hypertrophy, tremor and increased blood pressure. These negative effects have been identified through morphological alterations and/or clinical parameters, i.e. variation in glomerular filtration rate for nephrotoxicity. Nevertheless, CsA remains a therapeutic valuable agent and it is normally utilized into clinical practice even if different dose adjustments or discontinuations in a significant percentage of patients must be used. This review focuses on the following topics: mechanisms of action and drug metabolism, interactions with other drugs, clinical and morphological evaluation of toxic effects on target organs. In particular, the morphological evaluation of negative effects has been considered reporting light and ultrastructural studies on target organs both in normal and immunosuppressive conditions. Moreover, the histochemical and immunohistochemical variations in cellular metabolism and antigenic properties of cells present in the parenchyma of these organs are discussed.

Animals↗
PubMed1991

Biochemical and histochemical observations on effects of low-level heavy metal load (lead, cadmium) in different organ systems of the freshwater crayfish, Astacus astacus L. (Crustacea: Decapoda).

The effects of low-level lead (20 micrograms/liter) and/or cadmium (2 micrograms/liter) exposure on the structure and function of different organ systems of the freshwater crayfish. Astacus astacus L. (Crustacea: Decapoda) were estimated by several biochemical and histochemical methods. The animals were incubated during 10 weeks (max.) at a temperature of 10 degrees C and a normal diurnal rhythm. Lead accumulated in high amounts especially in the digestive gland, carapax, and gills, whereas the hindgut and musculature exhibited very low lead levels. Cadmium accumulated particularly in the digestive gland and gills. Lead and cadmium levels were definitely lower in the digestive gland, gills, and carapax of animals incubated in water containing a double, i.e., lead and cadmium load, than in animals kept in water containing only one of these heavy metals. Histochemically both metals could be visualized in a typical distribution within the tissues, such as the carapax, digestive gland, or gills. After several weeks of poisoning, all organs, but especially the digestive gland, showed severe structural impairment. The activities of oxidative enzymes in the digestive gland and gills were significantly lowered after 2 weeks of incubation. Enzyme histochemical evaluation demonstrated changes of reaction intensities within the organs as compared to the controls. GSH S-transferase activities and GSH contents were also distinctly decreased following lead and/or cadmium intoxification. The histochemical demonstration of SH and S-S groups exhibited a stronger staining reaction after 10 weeks of exposure, especially in digestive gland and gills. The results obtained are discussed in view of the specific impairment of function of the organ systems studied, as related to the typical biology of the animal species tested.

Animals↗