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1

Transepithelial transport of sodium and chloride ions in isolated skin of the frog, Rana esculenta

100%
Kosik-Bogacka D. I., Tyrakowski T.
Folia Biologica
|
2002
|
vol. 50
|
issue 3-4
107-114
EN
Isolated frog skin, mounted in a Ussing apparatus, was investigated electrophysiologically. Application of amiloride, an inhibitor of sodium ion transport, and bumetanide, known to block the transport of chloride ions, revealed the effect of these ions on PD, both under control conditions and following mechanical stimulation. Under control conditions, mechanical stimulation of the skin caused hyperpolarization, i.e. a transient increase in the electrical potential difference. Preincubation in the presence of amiloride, or amiloride plus bumetanide, brought about both a decrease in electrical potential and an inhibition of the reaction upon stimulation. On the other hand, incubation with bumetanide resulted in a decrease in electrical potential, but did not affect the skin reaction after mechanical stimulation. The above results indicate that hyperpolarization of the frog skin following mechanical stimulation is caused by enhanced transepithelial transport of sodium ions which, in turn, is induced by stimulation of sensory receptors.
2

Electrophysiological effect of ruthenium red and pH on the skin of the frog, Rana esculenta L.

100%
Kosik-Bogacka D. I., Tyrakowski T.
Folia Biologica
|
2001
|
vol. 49
|
issue 3-4
273-277
EN
Amphibian skin is a sensitive interface between the organism and the environment. Metal ions from the external environment, some of them being trace elements, act on the amphibian skin. It had been shown that stimulation of tactile receptors affected Na+ transport in the frog skin and changed the potential difference, therefore the aim of this project was to study the effect of ruthenium complex, known as ruthenium red (RR), on the ion transport in this organ in vitro under control conditions, after mechanical stimulation and also in the presence of the Na+ transport inhibitor-amiloride. Three different concentrations of RR (0.12, 1.2, and 12.0 mM) in two different pH values (6.4 and 7.4) were studied in vitro in the Ussing apparatus. The measured electrophysiological parameters were the transepithelial electrical potential difference (PD) and the changes in PD after mechanical stimulation (dPD). The gentle mechanical stimulus was a jet of bath fluid from a peristaltic pump directed on the mucosal surface of isolated frog skin. After mechanical stimulation, transient hyperpolarization invariably occurred (dPD = 1.5_0.2 mV). In the presence of RR the hyperpolarization was smaller and this diminution was concentration dependent: 0.5_0.1 mV for 1.2 mM of RR and 0.1_0.1 mV for 1.2 mM of RR. At pH 6.4 the reactions of the skins on the mechanical and chemical stimuli were smaller, in the presence of amiloride disappearing completely, but after the washing away of amiloride from the experimental organ in pH 6.4 the action of RR was stimulatory. The natural defensive reactions of frog skin related to the ion transport and electrical potential difference are affected or disappear in the presence of ruthenium complex.
3

Mitochondria and aging: innocent bystanders or guilty parties?

100%
Tonska K., Solyga A., Bartnik E.
Journal of Applied Genetics
|
2009
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vol. 50
|
issue 1
55-62
EN
. There are many theories of aging and a number of them encompass the role of mitochondria in this process. Mitochondrial DNA mutations and deletions have been shown to accumulate in many tissues in mammals during aging. However, there is little evidence that these mutations could affect the functioning of aging tissues.
4

Effect of bromocriptine on the larval skin of the green toad, Bufo viridis viridis Leurenti

100%
Al-Adhami M. A., Qar J.
Folia Biologica
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2007
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vol. 55
|
issue 1-2
41-46
EN
In the premetamorphic larval green toad, B. viridis viridis, as in other anurans, the skin is made up of a fibrous dermis and an epidermis of stratified epithelium. The effects of bromocriptine, an antiprolactin drug, on the premetamorphic skin of B. viridis viridis was examined. Bromocriptine, dissolved in rearing water at four different concentrations, induced a number of changes in the skin of treated tadpoles. In rough sequence of appearance, these changes include: retraction of the melanocyte dendrites, synchronous burst of the apical vesicles of the superficial epithelial cells, gradual disappearance of the melanosomes from the epithelial cells and widening of the intercellular spaces. In addition, macrophages appeared in the superficial dermis amongst the retracted melanocytes. White crystals were observed on the skin surface and similar crystals were ingested by the macrophages. Prolonged treatment with bromocriptine resulted in hypertrophy and extraction of some epidermal cells. Deep melanocytes of the mesenteries were not affected by bromocriptine- treatment indicating that the drug did not penetrate deep into the tadpole tissue. Whether the macrophages observed in the dermis were recruited from deeper tissues or were converted melanocytes is another issue in need of study.
5

Pathogenetic mechanisms of atopic dermatitis

88%
Pastore S., Giustizieri M. L., Mascia F., Giannetti A., Girolomoni G.
|
|
vol. 48
|
issue 5
497-504
EN
Atopic dermatitis (AD) is a chronic inflammatory disease which results from complex interactions between genetic and environmental mechanisms. An altered lipid composition of the stratum corneum is responsible of the xerotic aspect of the skin, and determines a higher permeability to allergens and irritants. Keratinocytes of AD patients exhibit a propensity to an exaggerated production of cytokines and chemokines, a phenomenon that can have a major role in promoting and maintaining inflammation. Specific immune responses against a variety of environmental allergens are also implicated in AD pathogenesis with a bias towards Th2 immune responses. In particular, dendritic cells expressing membrane IgE receptors, play a critical role in the amplification of allergen-specific T cell responses. Cross-linkage of specific IgE receptors on dermal mast cells provokes release and synthesis of a vast series of mediators. Following their recruitment and activation into the skin, eosinophils are also thought to contribute relevantly to tissue damage. Thus, a complex network of cytokines and chemokines contributes to establish a local milieu that favors the permanence of inflammation in AD skin.
6

Comparison of proliferation and motile activity between human keratinocytes isolated from skin and oral muco

88%
Drukala J., Zarzecka J., Gojniczek K., Waligorska A., Zapala J., Korohoda W.
Folia Biologica
|
2005
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vol. 53
|
issue 1-2
21-28
EN
Objective: Epithelial wound repair assures the recovery of the epithelial barrier after wounding. During wound healing epithelial cells migrate to cover the wound surface. For healing of skin wounds the skin keratinocytes can be replaced by oral mucosa epithelial cells grown in vitro. The presented experiments were carried out in order to compare the proliferation, morphology, and migration between human keratinocytes isolated from human skin and oral mucosa. Materials and methods: Human epidermal and oral mucosa keratinocytes from primary culture were used in all experiments. Cell motility and shape were determined using computer-aided methods. Results and conclusions: It was demonstrated that although both cell types exhibit the same typical epithelial morphology, oral mucosa keratinocytes locomote significantly faster than skin keratinocytes. They also differ in proliferation activity. Oral mucosa keratinocytes exhibited faster growth and different actin cytoskeleton organisation than skin keratinocytes under in vitro conditions. Autologous oral mucosa keratinocytes may be expanded in vitro and used for skin wound healing in vivo.
7
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Brainstem neurones and postganglionic sympathetic nerves:does correlation mean connection ?

75%
McAllen R. M., May C. N.
Acta Neurobiologiae Experimentalis
|
1996
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vol. 56
|
issue 1
129-135
EN
Short-term correlations in activity have been widely used as evidence to connect brainstem units with postganglionic sympathetic nerves. These may be detected by spike-triggered averaging, cross correlation of coherence analysis. The specificity of this type of evidence has been investigated by cross-correlating the activity of identified cutaneous vasoconstrictor postganglionic fibres with that of medullary premotor neurones of like and of unlike functional type, as determined by physiological testing (preoptic warming), in anaesthetised cats. Single medullary premotor neurones of both types were recorded from the subretrofacial nucleus: they were identified by their berosensitivity and, in most cases, their spinally projecting axons. By the test criteria chosen, the correlation method gave both false-positive and false-negative results as commonly as it gave correct ones. We conclude that it is not a reliable way to determine brainstem-postganglionic connectivity.
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