Comparison of the influence of halothane and isoflurane on airway transepithelial potential difference.

Bidirectional transport of Na+ and Cl- ions by the epithelium controls production and composition of airway surface liquid and airway transepithelial potential difference and in these ways supports mucociliary transport. Volatile anesthetics are able to inhibit epithelial ion transport processes when applied at high concentration and have been suggested to elicit depression of airway clearance and both these effects could be involved in postoperative pulmonary complications. The goal of these studies was to reveal possible influence of halothane and isoflurane at lower concentrations on electrogenic ion transport in airway epithelium. These studies were performed on the isolated rabbit tracheal wall mounted in the Ussing chamber. The reaction of the preparation to the gentle mechanical stimulation performed as a jet flux was examined without or in the presence of anesthetics at concentration equivalent to 0.5 minimal anesthetic concentration of volatile anesthetics in pulmonary alveoli (MAC), 1 MAC, 2 MAC, 5 MAC and 10 MAC. The volatile anesthetics at concentrations equivalent to 5 and 10 MAC affected airway transepithelial potential difference and influenced hyperpolarization or depolarization reactions which occurred after mechanical stimulation. The above effects were present when Na+ transport was inhibited by amiloride. The disturbed epithelial Cl- transport may be proposed as an explanation of the action of volatile anesthetics on electrophysiological parameters of the isolated tracheal wall although the influence of anesthetics on tachykinin secretion from C-fiber endings, which are present in the preparation, should also be taken into consideration. The long-lasting action (tens of minutes) of volatile anesthetics on the isolated tracheal wall should be also studied in the future as a model of airway reaction to prolonged volatile anesthesia.

Mebeverine influences sodium ion transport in the distal colon.

The study was performed to check if the well-known intestinal spasmolytic effect of mebeverine is paralleled by any changes in intestinal transepithelial currents. The transepithelial potential difference related to ionic currents of the isolated rabbit distal colon wall was measured by means of Ussing's technique under control conditions and after gentle mechanical stimulation of intestinal epithelial surface by a flux from peristaltic pump and with and without of mebeverine in stimulation fluid. The transient hyperpolarization after mechanical stimulation was diminished after addition of mebeverine to the stimulation fluid when chloride transport was inhibited by bumetanide (BUME) but in the presence of amiloride (AMI), a sodium ion transport inhibitor, the drug did not influence the reaction. It was inferred that mebeverine was able to modulate transepithelial sodium ion transport and in this way to modify interaction between colonic wall and its contents during intestinal passage.

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 snail's 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.

[How could telemedicine improve the quality of health care in Poland?]. / Czy telemedycyna moze poprawic jakosc polskiej opieki zdrowotnej?

From the view-point of the health-care system there is possibility of application of modern communication and informatics technologies to optimize some important aspects of patient treatment. This new fields of medical interest are called: telemedicine and medical telecare. Telemedicine deals with distance diagnose (for example: during emergency transport) and specialist consultations based on videoconferencing programs. Medical telecare concerns with home monitoring of patients with chronic diseases by means of computer control of important diagnostic parameters and automatic signaling when the variables exceed the defined values. Both disciplines share problems of standards of electronic medical documentation, virtual medical care networks and tele-education of health-care professionals and patients. The preliminary trials of introduction of some telemedicine programs in the health service units of local and specialist levels should make possible to evaluate the applicability and advantages of using these technologies in the whole Polish health care system in the future.