Biomedical subjects

Tomasz Tyrakowski

Publications and source records attributed to Tomasz Tyrakowski.

At least 19 recordsLinked to original sources

PubMed2006

The effect of serotonin on epinephrine modulation of transepithelial ion transport in isolated frog skin.

The aim of this study was to examine the effect of serotonin and epinephrine on ion transport of isolated frog skin. The addition of serotonin after incubation in Ringer solution (RH), bumetanide (BUME), and after initial incubation in amiloride and subsequently in RH, reduced hyperpolarization and did not effect the mechanosensitivity of frog skin. Following incubation of the frog skin with amiloride (AMI), serotonin did not affect the value of hyperpolarization and increased mechanosensitivity. The addition of epinephrine (EPI) on frog skin incubated in RH and AMI did not affect hyperpolarization, but repeated application of this compound after serotonin increased hyperpolarization. After incubation with bumetanide, addition of EPI before and after application of serotonin did not affect the value of the examined parameters of the frog skin. Initial incubation with AMI and later in RH caused a drop in reaction to EPI and no effect on mechanosensitivity. Repeated addition of epinephrine in this group did not affect the reaction value, while it decreased the reaction value during mechanical stimulation. The experimental data presented in this study indicate that serotonin inhibits the sodium ion current. Epinephrine inhibits the chloride ion current, however, after the application of serotonin, EPI stimulates sodium ion transport.

Animals↗

PubMed2006

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.

Animals↗

PubMed2006

[BRAF gene mutation in thyroid cancer].

Mutations of genes coding effectors of signaling pathway RET/PTC-RAS-RAF-MEK-ERK, involved in cell growth and proliferation, are important in papillary thyroid cancer development. To earlier discovered mutations of RAS and RET/PTC genes, BRAF gene mutation has been recently added. Mutation of BRAF gene appears in various types of carcinomas, but most frequently in malignant melanomas (66%) and papillary thyroid cancer (average 44%). The BRAF gene protein product belongs to the serine-threonine kinase family and to the RAF proteins subfamily, among which it is the strongest activator of MAP kinases cascade. The most frequently mutation of BRAF gene is thymine to adenine transversion at nucleotide position 1796 (T1796A). This point mutation causes valine to glutamic acid substitution at residue 599 (V599E), that results in constitutive and oncogenic activation of BRAF kinase. The relation between mutations of BRAF, RAS and RET/PTC genes has not been found, although they together exist in two thirds of papillary thyroid cancers. BRAF(TI796A) oncogene appears in papillary thyroid cancer, whereas it has not been found in follicular thyroid cancer and benign thyroid adenomas. For this reason mutated BRAF gene could be specific molecular marker, with relatively high sensitivity in diagnostics of papillary thyroid cancer. In addition, BRAF gene has been demonstrated as a novel prognostic biomarker, which correlates with unfavorable clinicopathological factors, such as extrathyroidal invasion and distant metastasis.

Carcinoma, Papillary↗

PubMed2006

[Iron status with particular consideration of soluble transferrin receptors in children and youth with gastritis, with or without Helicobacter pylori infection].

UNLABELLED: Role of Helicobacter pylori infection in chronic gastritis and gastric and/or duodenal ulcers is well known. Simultaneously there are some articles in literature considering H. pylori as a cause of extra-gastrointestinal illnesses such as atopic dermatitis, chronic urticaria or acne rosacea, hypotrophy, Schoenlein-Henoch disease, atherosclerosis or hypochromic anaemia. The aim of the study. was to asses iron status in aspect of plasmatic transferrin receptors concentration among children and youth with chronic gastritis with or without Helicobacter pylori infection. MATERIALS AND METHODS: Forty one patients were included as a study group. Range of age was 9-18 years. All patients were diagnosed due to chronic abdominal pains. There were 13 males and 28 females. Blood was collected from every patient for blood cell count, iron, transferrin and transferrin receptors concentration (sTfR) assessment before endoscopy of upper gastrointestinal tract. RESULTS: Concentration of sTfR was higher than age norm among 29 (71%) of patients. Among patients with higher level of sTfR 20 (69%) had normal haemoglobin concentration and in this group 10 patients had H. pylori infection. During analysis of 12 patients with nornal level of sTfR normal haemoglobin concentration was found and among five of them H. pylori infection was stated. Among 21 patients without H. pylori infection 14 had normal level of sTfR and 7 had higher level of sTfR which means that 33% had hidden iron deficiency (involuntary of normal Hb concentrations). Among 15 of 20 patients with H. pylori infection level of sTfR was higher which means that 75% patients with infection had hidden iron deficiency (involuntary of normal Hb concentrations). CONCLUSION: Level of plasmatic transferrin receptors can be good and sensitive indicator of iron deficiency and can be helpful in differential diagnosis of hypochromic anaemia and anaemia caused by chronic illness including chronic gastritis with Helicobacter pylori infection.

Adolescent↗

PubMed2005

Effect of amiloride and bumetanide on transepithelial ion transport in isolated rabbit cecal and colonic wall.

INTRODUCTION: The aim of the study was to compare the effects of amiloride and bumetanide on the baseline transepithelial electrical potential difference (PD) and changes in PD during mechanical stimulation (dPD) in isolated cecal and colonic wall of rabbits. MATERIAL/METHODS: The experiments were performed with a modified Ussing chamber system. Isolated tissue specimens were incubated in Ringer's solution, in amiloride and/or bumetanide, or in dimethyl sulfoxide (DMSO). RESULTS: Under control conditions, i.e. when all the experimental fluids were Ringer's solution, the PD and R values of the rabbit cecum and colon were similar, while during mechanical stimulation, dPD of the colon was twice as high as that of the cecum. Addition of amiloride and/or bumetanide to all experimental fluids diminished the electrophysiological parameters of both tissues. DMSO added to all experimental fluids significantly diminished the values of the electrophysiological parameters of the cecum. Addition of amiloride to the stimulation fluid only diminished the PD and dPD values in the colon, whereas addition of bumetanide to the stimulation fluid only diminished the PD and dPD values in the cecum. It was found that the PD and dPD values of the rabbit cecum depend primarily on chloride ion transport, while those of the colon depend on sodium ion transport.

Amiloride↗

PubMed2005

[How could telemedicine improve the quality of health care in Poland?].

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.

Humans↗

PubMed2004

Postmortem examination of transepithelial ion currents in rabbit colon and trachea in relation to temperature of storage and its importance for interlethal reactions.

Electrical phenomena resulting from transepithelial ion transport have been a subject of clinical, physiological, pharmacologic and toxicologic studies. These examinations concern mainly electric phenomena in live organisms. The changes of transepithelial ion pathways which take place postmortem have not been yet established. The aim of the study was an attempt to trace variability of electrophysiological parameters related to transepithelial ion transport in specimens of rabbit trachea and colon depending on temperature at which specimens were stored after death. It was observed that postmortem electric phenomena in epithelium of airways and alimentary tract of rabbit occur well-ordered but with slower course in trachea samples and in tissues which were preserved at low temperature after death.

Animals↗

PubMed2004

[Parameters of lipid peroxidation and low density lipoprotein (LDL) oxidation in the course of hyperthyroidism].

The aim of this study was to evaluate the influence of hyperthyroidism on lipid peroxidation and oxidative modification of low density lipoprotein (LDL). Twenty patients with hyperthyroidism due to Graves' disease or toxic multinodular goitre and 17 healthy subjects as the control group were investigated. Lipid peroxidation was measured by the serum level of malondialdehyde and 4-hydroxynonenal (MDA+4-HNE) whereas the oxidative modification of LDL was determined by measuring the serum levels of antibodies against oxidized LDL (anti-oxLDL). Ratios, which were evaluated as proportions of lipid peroxidation products level or anti-oxLDL level to the LDL-cholesterol level (LDL-C) were also determined: MDA+4-HNE/LDL-C and anti-oxLDL/LDL-C. The patients with hyperthyroidism displayed a significant elevation of the MDA+4-HNE/LDL-C ratio. The level of anti-oxLDL and anti-oxLD/LDL-C ratio were positively correlated with FT4 level and inversely correlated with HDL-cholesterol. These data suggest that the intensification of lipid peroxidation and oxidative modification of plasma lipoprotein is affected by changes in the level of thyroid hormones.

Adult↗

PubMed2003

Effect of capsaicin and dimethyl sulphoxide (DMSO) on ion transport in isolated skin of frog (Rana esculenta L.).

The effects ofcapsaicin, dimethyl sulphoxide and pH changes on transport of sodium and/or chlorine ions in an isolated frog skin, were studied using electrophysiological methods, adapted to evaluation of ionic currents occurring in the epithelial tissues and organs. The experiment consisted in measuring potential difference (PD in mV) of an isolated skin of the aquatic frog, Rana esculenta L., placed in a Ussing apparatus. The ionic transport processes were modified through incubation of the tissue in Ringer solution and in Ringer solution supplemented with amiloride, bumetanide, and also with dimethyl sulphoxide. The direct effect of capsaicin and dimethyl sulphoxide (DMSO) on frog skin was assessed while these compounds were added to the Ussing chamber with a pipette and a peristaltic pump. Adaptive reactions of the tissue were assessed following at least 60-min exposure to those compounds. It has been demonstrated that amiloride-inhibited sodium ion transport and acidification of the incubation medium (pH 6.4) inhibited mechanically induced epithelium reactions. Both compounds, capsaicin and DMSO modified ionic transport processes depending on the mechanical stimulation.

Animals↗

PubMed2002

Model study of toluene diisocyanate effect on transepithelial ion transport.

BACKGROUND: Toluene diisocyanate (TDI), a low molecular weight compound, is commonly known as a factor causing asthma in chemical industry workers. The present study investigated a possible effect of TDI on ion transport using electrophysiological methods aimed at assessment of ion currents occurring in epithelial tissues. MATERIAL/METHODS: The experiments were carried out on 119 fragments of isolated frog skin, sampled from 59 specimens of hybrid frog Rana esculenta L. The procedures employed involved transepithelial electrical potential (PD in mV) measurement with an Ussing apparatus, modified to enable mechanical stimulation of organs and defined pharmacological actions. Incubation was carried out using Ringer solution and Ringer solution with amiloride and bumetanide. Direct actions of toluene diisocyanate (TDI) were assessed at the time of administering this substance to the Ussing chamber with a peristaltic pump. RESULTS: Based on the model of frog skin tested with Ussing apparatus, administration of TDI to the fluid stimulating preparations incubated with Ringer solution (RH) and with amiloride (AMI) was demonstrated to cause a hyperpolarization increase after mechanical stimulation. TDI action on isolated frog skin inflicted a change in response to mechanical stimulation, leading to a depolarization. The reaction magnitude of frog skin incubated with bumetanide (BUME) did not change due to TDI. CONCLUSIONS: TDI influences processes of sodium ion transport in the isolated frog skin model, depending on mechanical stimulation. This indicates that TDI effect on ion transport in epithelial cells depends on C fibres and tachykinins released from their endings.

Amiloride↗

PubMed2002

Effect of ambroxol on ion transport -- a model study.

BACKGROUND: Effect on ambroxol on reflexive physiological reactions of isolated frog skin was studied with electrophysiological methods designed to assess ion currents occurring in epithelial tissues or organs. The experiments permitted to analyze an effect of ambroxol on regulatory mechanisms, which in turn influence the constant electrical potential defined as PD and reversible changes of this potential during mechanical stimulation (marked as dPD). A contribution of sodium- and chloride ions transport to the value of transepithelial electrical potential of frog skin (before and after ambroxol administration) has been demonstrated using amiloride - a blocker of sodium ion transport and bumetanide - a blocker of chloride ion transport. MATERIAL/METHODS: The experimental material comprised 34 fragments of hybrid frog (Rana esculenta L.), representing 14 specimens. The experiments involved measuring the transepithelial electrical potential (PD in mV) on an isolated frog skin placed in an Ussing apparatus. RESULTS: It has been demonstrated that ambroxol influences the processes of ion transport (dPD) which in turn depend on mechanical stimulation. The reaction of hyperpolarization decreased immediately after administration of ambroxol to the stimulating fluid, when transepithelial transport of sodium ion was maintained in the preparations studied. Consequently, no effect of ambroxol on the frog skin incubated with amiloride was recorded. CONCLUSIONS: It has been demonstrated, based on the experiments carried out in the present study, that ambroxol can modify processes of ion transport related to activation of sensory receptors. In particular, it can influence the stimulated transepithelial sodium ion transport in frog skin.

Ambroxol↗

PubMed2002

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

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.

Animals↗

PubMedDate not supplied

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.

Animals↗

PubMedDate not supplied

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.

Amiloride↗

PubMedDate not supplied

Effects of amiloride and bumetanide on ion transport in the caecum of rabbit.

Effect of selective blockers of sodium and chloride ion transport (amiloride and bumetanide) on transepithelial electrical potential (PD), transepithelial electrical potential difference (dPD), and electrical resistance of the tissue (R) of isolated fragment of the rabbit's caecum were determined using electrophysiological methods designed for measuring ionic currents occurring in epithelial tissues. A modified Ussing apparatus enabling application of mechanical and chemical stimuli on the isolated tissue was used in the experiment. It was demonstrated that amiloride used for incubation of the caecum fragments lowered by some 24% the value of PD and by 50% the value of dPD. Incubation of the caecum fragments with bumetanide resulted in a decrease in the PD value by 73% and in the value of dPD by some 83%. The results obtained with the tissue incubated in Ringer solution with addition of both compounds were comparable with those observed for the tissue incubated with bumetanide. As can be concluded from the above-mentioned experiments, both ion transport pathways contribute jointly to the induction of PD in the epithelium of the rabbits caecum.

Amiloride↗

PubMedDate not supplied

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.

Amiloride↗

PubMedDate not supplied

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.

Adrenergic Antagonists↗

PubMedDate not supplied

[The concentrations of homocysteine, folic acid and vitamin B12 in alcohol dependent male patients].

UNLABELLED: Metabolism of homocysteine (sulphur-containing amino acid) is accomplished in the remethylation cycle where vitamin B12 and folic acid are essential coenzymes. Markedly elevated homocysteine concentrations have been observed in patients with nutritional deficiencies of vitamin B12 and folate. Hyperhomocysteinemia in alcohol abusers may result from malnutrition and disorder of intestine absorption. AIM: The aim of the study was the estimation of homocysteine, folic acid and vitamin B12 concentrations in alcohol dependent male patients. METHOD: 71 males with a clinical diagnosis of alcohol dependence (ICD-10) have been examined. The investigated parameters have been determined in the blood serum, the homocysteine by means of immunochemical method, vitamin B12 and folic acid by means of immunoenzymatic assay. RESULTS: Serum homocysteine concentration was significantly higher and serum folic acid concentration was lower in alcohol dependent men than in controls. Mean concentrations of folic acid and vitamin B12 were significantly lower in patients with hyperhomocysteinemia than in men with normal homocysteine concentration. The highest correlation was indeed noticed between folate deficiency and the intensity of hyperhomocysteinemia. CONCLUSIONS: The development of hyperhomocysteinemia is associated with alcohol dependence that is also a probable cause of folate and vitamin B12 deficiency.

Adult↗