Magdalena Lampka

Toluene diisocyanate caused electrophysiological disturbances in the upper airways wall.

OBJECTIVES Toluene diisocyanate (TDI) due to its widespread use in industry is one of the most common and well-known causes of occupational asthma and Reactive Airways Dysfunction Syndrome (RADS). In this study the impact of TDI on the electrophysiological properties of the airways wall, particularly on the mechanisms of absorption of sodium ions and chloride ions secretion was evaluated. MATERIALS AND METHODS Isolated rabbit tracheal wall (from outbred stock animals) was mounted in an apparatus for electrophysiological experiments by means of Ussing method and was mechanically stimulated by the jet flux of specified fluid directed onto the mucosal surface of the tissue from a peristaltic pump. The measured parameters were: transepithelial potential difference under control conditions (PD, mV), after mechanical stimulation (dPD or physiological reaction of hyperpolarization, mV) and electric resistance (R, Omega cm2). When TDI (0.035 mM) was added to stimulation fluid, only the immediate reaction was identified and when it was added to incubation fluid and other experimental fluids, the late (post-incubation) reaction was determined. The experiments involving the inhibition of Na+ by amiloride and Cl- by bumetanide were also performed. RESULTS A series of functional tests for 72 pieces of tracheal wall from 36 animals were performed. It has been shown that short-term exposure to TDI significantly changed the course of reactions to mechanical stimulation. Also after incubation in the presence of TDI, the reactions to mechanical stimulation were changed in relation to control conditions. CONCLUSIONS The immediate reaction of the isolated rabbit tracheal wall after exposure to TDI depends on the duration of exposure and on the physiological condition of the tissue in respect of sodium and chloride ion transport.

Capsaicin Used on Skin Influences Ion Transport Pathways: An in vitro Study

Acute, adverse skin effects to capsaicin can be activated by inhibition of sodium transport not only in nociceptive neurons, but also in keratinocytes. The aim of the current study was to describe and compare immediate (15 s) and prolonged (30 min) effects of capsaicin on epidermal (not neural) sodium transport using a rabbit skin model. Skin fragments (n = 169) were incubated in 4 conditions: undisturbed ion transport (U; n = 48); inhibited sodium transport (INa; n = 34) with amiloride used as sodium transport blocker; long-term irritation by capsaicin with undisturbed ion transport (CAPSA-U; n = 43) and with inhibited sodium transport (CAPSA-INa; n = 35). After 30 min of incubation, a solution of capsaicin was applied directly to the skin fragments. The study demonstrated that sodium transport inhibition eliminated the effects of both immediate and prolonged capsaicin application. The results could be the basis for future research considering selective sodium transport inhibitors for human skin to reduce the side effects of capsaicin, related to activation of sodium channels in keratinocytes.

The immediate influence of deltamethrin on ion transport through rabbit skin. An in vitro study

Deltamethrin can be absorbed into the respiratory tract, the gastrointestinal tract and through the skin. The study was designed to assess the effect of deltamethrin on electrophysiological parameters of rabbits skin, studied in vitro, to identify the mechanism of action and effects of short-term dermal exposure to deltamethrin. The objective of the study was to investigate changes in electrophysiological parameters after exposure to 0.01 M deltamethrin under unchanged conditions, in the presence of amiloride (sodium transport blocker) and bumetanide (chloride transport blocker). Exposure to deltamethrin reduced the electrophysiological reaction of examined tissue in unchanged conditions and during the sodium reabsorption phase but did not influence the chloride ion secretion phase. The presented data show that the pyrethroide affects transepithelial ion transport in the external layers of the skin. The inhibition of chloride and sodium ions enabled evaluation of the impact of the pesticide on dermal transport.

Investigation of oxidative stress in patients with alopecia areata by measuring the levels of malondialdehyde and ceruloplasmin in the blood

Introduction Alopecia areata (AA) is a chronic, inflammatory and autoimmune disease, presenting with non-scarring hair loss. Although the precise etiopathogenesis of AA remains unknown, oxidative stress is thought to play a role. Aim To investigate the role of oxidative stress in AA by measuring the levels of plasma and erythrocyte malondialdehyde (MDA) and the ceruloplasmin (CER) in serum. Material and methods The study included 24 AA patients and a control group consisting of 24 age- and sex-matched healthy volunteers. The levels of MDA and CER were measured and compared between groups. Results Plasma MDA levels were significantly higher (p < 0.05) in patients with AA compared with controls. No significant difference was observed in MDA erythrocyte levels (p = 0.990) between the study group and the control group. Ceruloplasmin level was higher in the AA group, but this increase was not statistically significant (p = 0.156). Conclusions Patients with AA displayed significant plasma MDA levels, which could lead to damage in erythrocytes exposed to high concentrations of free radicals. These results demonstrate the presence of an imbalance in the oxidant-antioxidant system and support the concept of a possible role of oxidative stress in AA etiopathogenesis.

The Electrical Potential Difference through the Foot Epithelium of the Snail Achatina achatina, Lameere during Mechanical and Chemical Stimulation

An important electrophysiological variable--the transepithelial potential difference reflects the electrogenic transepithelial ion currents, which are produced and modified by ion transport processes in polarized cells of epithelium. These processes result from coordinated function of transporters in apical and basolateral cell membranes and have been observed in all epithelial tissues studied so far. The experiments were performed on isolated specimens of snail foot. In the experiments, the baseline transepithelial electrical potential difference--PD, changes of transepithelial difference during mechanical stimulation--dPD and the transepithelial resistance were measured with an Ussing apparatus. A total of 60 samples of foot ventral surface of 28 snails were studied. The transepithelial electrical potential difference of isolated foot ranged from -6.0 to 10.0 mV under different experimental conditions. Mechanical stimulation of foot ventral surface caused changes of electrogenic ion transport, observed as transient hyperpolarization (electrical potential difference became more positive). When the transepithelial electrical potential difference decreased during stimulation, the reaction was described as depolarization. When amiloride and bumetanide were added to the stimulating fluid so that the sodium and chloride ion transport pathways were inhibited, prolonged depolarization occurred. Under the influence of different stimuli: mechanical (gentle rinsing), chemical (changes of ion concentrations) and pharmacological (application of ion inhibitors), transient changes of potential difference (dPD) were evoked, ranging from about -0.7 to almost 2.0 mV. Changes in transepithelial potential difference of the pedal surface of the snails foot related to these physiological stimuli are probably involved in the locomotion of the animal and are under control of the part of the nervous system in which tachykinin related peptides (TRP) act as transmitters.