Effect of capsaicin on ion transport in the caecum of rabbits

Effect of capsaicin, a stimulator of C-fibres, on ion transport in the caecum of rabbits was studied using electrophysiological methods, designed to evaluate ionic currents occurring in epithelial tissues. The experiments consisted in measuring transepithelial electrical potential difference (dPD) of an isolated fragment of rabbit's caecum, placed in a Ussing apparatus. The ion transport was modified through incubation in Ringer solution, supplemented with amiloride, bumetanide, and capsaicin. Capsaicin was also administered with peristalting pump. The experiments demonstrated that the inhibition of sodium ions transport caused by incubation with amiloride and incubation with capsaicin slowed down mechanical reaction to electrical potential difference. On the other hand, immediately after the administration, the capsaicin effect on C-fibres modified electrophysiological reaction of the caecum to mechanical stimulation. Physiological and pharmacological experiments reveal that a component dependent on activation of C-fibres contributes to the reaction of ion transport activation following mechanical stimulation.     

Effect of antagonists of adrenergic and cholinergic receptors on ion transport in the isolated rabbit caecum wall

A hypothesis was tested in this study that antagonists of adrenergic and cholinergic receptors affect sodium and chloride ion transport in the rabbit caecum. A modified Ussing chamber was used in the experiment. It was demonstrated that isolated caecum responded to a mechanical stimulus, which consisted in gentle rinsing of the mucous surface, with changes in transepithelial electrical potential difference. An application of ion transport inhibitors, amiloride for sodium and bumetanide for chloride ions, demonstrated that both sodium and chloride ion transport in part determined the response. Pharmaceuticals that are antagonistic at neural receptors (alpha- and beta-adrenergic, nicotinic, and muscarinic), applied both for incubation and stimulation, reduced electrical potential and inhibited responses to mechanical stimuli. Basing on the results of this experiment and literature data, one can presume that analogical responses occur in vivo, and the physiological role of the autonomic system includes regulation of the thickness and consistence of mucus that separates fecal masses from the caecum walls.     

Comparison of Hepatic and Nephric Total Mercury Concentrations Between Feral and Ranch American Mink (Neovison vison) from Northwestern Poland

For many years the American mink (Neovison vison) has been used in North America (where it originates from) as a sensitive indirect bioindicator in assessing the degree of mercury (Hg) contamination in terrestrial ecosystems. The aim of this paper was the determination of total concentrations of Hg in the liver and kidneys of feral and ranch mink from the Warta Mouth National Park (WMNP) and from farms located in northwestern Poland, for comparison with similar data on American mink from North America. In road-killed feral mink from the WMNP, the mean concentrations were 11.8 and 14.1 mg/kg dry weight in the liver and kidney, respectively. Mean Hg concentrations in feral mink were from 240 to 90 times higher in these two respective tissues than in ranch mink. The feral mink from northwestern Poland had concentrations of hepatic and nephric Hg similar to the highest concentrations that have been recorded over the past several decades in wild American mink from certain areas of Canada and the USA.     

Effect of amiloride and bumetanide on ionic currents in the epithelium of caecum from starved rabbits

The aim of this study was to determine the effect of starvation on the transport of sodium and chloride ions in the epithelium of rabbit caecum. The experiment consisted in measuring transepithelial electrical potential (PD in mV) and the transepithelial electrical potential difference (dPD in mV) of an isolated fragment of rabbit caecum, before and after 4-day-long starvation. The studied tissue was incubated in Ringer solution and subsequently ion transport was modified through incubation in the Ringer solution supplemented with amiloride or/and bumetanide. It was demonstrated that the values of electrophysiological parameters of the tissue fragments of caecum from starved rabbits were substantially lower than the values for the fragments of control caecum. A similar relationship was observed also in the reaction of this tissue to mechanical stimuli. After the incubation of the caecum tissue fragments in the presence of amiloride or/and bumetanide, the value of transepithelial electrical potential and the sensitivity to mechanical stimuli decreased in both groups studied. Experimental data presented in this paper indicate that the starvation process has effect on lowering sodium and chloride ion transport and decreasing sensitivity of the epithelium of the caecum to mechanical stimuli.     

Symptomatic and asymptomatic infections of Demodex spp. in eye lashes of patients of different age groups

Demodex folliculorum and Demodex brevis were looked for on eyelashes sampled from 481 people, aged 3 through 96. The persons studied were divided into 9 age groups. Magnitude of the infection symptoms was assessed based on macroscopic changes of eye-lid edges and on interviews with patients. An increase of the prevalence of infection and intensification of the symptoms were observed to coincide with the age increase of the persons studied. No significant differences were demonstrated between the infection frequencies of women and men. Symptoms of ocular demodecosis were more frequent only in women of group III (aged 21-30) and group V (41-50) (p < 0.05).     

Mercury in the Body of the Most Commonly Occurring European Game Duck, the Mallard (Anas platyrhynchos L. 1758), From Northwestern Poland

The aim of this study was to determine the concentration of mercury (Hg) in liver (L), kidney (K), breast muscle [BM (musculus pectoralis major)], breast feathers (BF), and stomach contents (SC) of mallard (Anas platyrhynchos L. 1758). Among the edible parts of mallard, the greatest concentrations of Hg were observed in K and L, although they did not exceed 1.5 mg/kg dry weight (dw). Average concentrations in K, L, and BM were 0.27, 0.25, and 0.13 mg/kg dw, respectively. Significant correlations were observed between Hg concentrations in BM and K and in BM and L (r _s = 0.92) as well as between Hg concentrations in these tissues and BF. In addition, we found significant correlations between Hg concentrations in SC and BM (r _s = 0.72) and in L and K (r _s = 0.55). In conclusion, mallard exhibits a measurable response to environmental Hg pollution and meets the requirements of a bioindicator.     

Effect of capsaicin and dimethyl sulfoxide on ion transport in the selected experimental models

The aim of the present work was to determine the changes in ion transport in the selected epithelium-lined organs under influence of mechanical stimuli, and also to assess similarities and differences in reactions to capsaicin and dimethyl sulfoxide (DMSO) between trachea and caecum of rabbit and the skin of frog in this experimental setup. The experiments were conducted on rabbit trachea and caecum, and the skin of frog, Rana esculenta L. The experiments consisted in measuring transepithelial electrical potential (PD in mV) with Ussing apparatus, modified to enable testing of the effects of mechanical stimulation of organs and defined pharmacological treatments. It was demonstrated that the addition of DMSO to the stimulating fluid decreased reversible hyperpolarization (dPD) after mechanical stimulation by at least 50% in all studied groups. On the other hand, action of capsaicin was dependent on the organ studied as well as on experimental conditions (e.g. type of incubation). Capsaicin decreased PD and reaction to mechanical stimulation in trachea incubated in Ringer solution supplemented with amiloride. On the other hand, it did not influence electrophysiological parameters of the trachea following its incubation with bumetanide. Capsaicin did not change electrical potential or reactivity of rabbit caecum incubated with both amiloride and bumetanide. The administration of capsaicin on frog skin incubated with bumetanide caused inhibition of the reaction to mechanical stimulation, whereas during incubation with amiloride no changes were recorded in PD and dPD of the skin. The present study demonstrated that capsaicin and DMSO could modify processes of ion transport dependent on mechanical stimulation.     

Selenium and mercury in the hair of raccoons (Procyon lotor) and European wildcats (Felis s. silvestris) from Germany and Luxembourg

Ecotoxicology - This study examined the concentration of total mercury (THg) and selenium (Se), as well as the molar ratio of Se:THg in hair samples of terrestrial animals. THg and Se...     

The Prevalence of Blastocystis hominis and Other Protozoan Parasites in Soldiers Returning from Peacekeeping Missions

Blastocystis hominis is a common intestinal parasite found in humans living in poor sanitary conditions, living in tropical and subtropical climates, exposed to infected animals, or consuming contaminated food or water. The aim of this study was to determine the prevalence of B. hominis in Polish military personnel returning from peacekeeping missions in Iraq and Afghanistan. In total, 1,826 stool samples were examined. Gastrointestinal parasites were detected in 17% of the soldiers. The examined stool samples most frequently contained vacuolar forms of B. hominis (15.3%) and cysts of Entamoeba coli (1.0%) or Giardia lamblia (0.7%). In 97.1% of stool samples from infected soldiers, we observed less than five developmental forms of B. hominis in the field of view (40×). The parasite infections in soldiers were diagnosed in the autumn and the spring. There was no statistical correlation between age and B. hominis infection. Our results show that peacekeeping missions in countries with tropical or subtropical climates could be associated with risk for parasitic diseases, including blastocystosis.