Biomedical subjects

J Woliński

Publications and source records attributed to J Woliński.

At least 19 recordsLinked to original sources

PubMed2005

Into the unknown--the death pathways in the neonatal gut epithelium.

Apoptosis is a fundamental process in the development of the fast growing intestinal mucosa. Apoptotic cells are present along the whole length of the villi and in the crypts. The mechanisms involved in the induction of apoptosis in the gut mucosa are still unknown. Cytokines are believed to play a role in auto- and paracrine models because the cells are dying in so-called "packets" containing neighboring cells. In the rapidly developing gut of neonates, the apoptosis rate is transiently reduced in the first days of life, enhancing the growth of mucosa. Afterwards, apoptosis plays a role in the exchange of the enterocyte population, facilitating maturation of the mucosa. The presence of autophagic cells has been confirmed for the first time in the developing gut. Deprivation of growth factors during feeding artificial milk formula led to an increased apoptosis rate. Supplementation with leptin reduced cell apoptosis and increased the mitosis-to-apoptosis ratio. Autophagy was also diminished. The key to healthy gut mucosa growth in early life, especially in fast-growing animals, is colostrum, which supplies nutritional and defensive components together with supplementary growth factors, cytokines and hormones essential for growth and maturation of gut mucosa.

Animals↗

PubMed2005

Light and scanning electron microscopy evaluation of the postnatal small intestinal mucosa development in pigs.

Modifications in the structure of gastrointestinal mucosa is often used to evaluate gut function for instance during the development or in response to particular food components. Scanning electron microscopy (SEM) gives a chance to observe the surface of the gut epithelium in three dimensions. However, this technique is seldom used due to technical difficulties. The present study attempted to investigate the intestinal mucosa structure changes in the postnatal pig using light and scanning electron microscopy technique. Experiments were carried out on sow reared piglets from birth until 38 days of age. Piglets were sacrificed at birth and at the 3(rd), 7(th), 21(st) and 38(th) day of life. The entire gastrointestinal tract was immediately harvested and the whole thickness tissue samples were taken from the duodenum, jejunum and ileum for optical and scanning electron microscopy. SEM analyses corroborated with histometry made by optical microscopy. Moreover, a number of shape modifications of the villi and its surface have been observed. The development changes in small intestine mucosa during the first 3 weeks were manifested in shape, size and density of villi. In conclusion, the structure of small intestinal mucosa undergoes profound structural changes. SEM gives a new dimension in the investigation of gut mucosa.

Animals↗

PubMed2004

Effect of Escherichia coli heat-labile enterotoxin on the myoelectric activity of the duodenum in weaned pigs.

The objective of the present study was to elucidate the effect of subclinical doses of Escherichia coli heat-labile enterotoxin (LT) on the antro-duodenal myoelectric activities of weaned pigs. Twelve weaned pigs were surgically implanted with three pairs of electrodes on the antrum 3 cm before the pylorus, 5 and 20 cm after the pylorus on the duodenum, respectively. An infusion cannula was inserted into the duodenum between duodenal electrodes. Using a wireless telemetry recording system, an electromyography (EMG) tracing lasting at least 24 h was recorded as the control, then another 24-h EMG recording was performed with a bolus intraduodenal infusion of LT (0.1 and 0.5 microg/kg b.w.). After a 1- to 2-day break, a 5-fold higher dose of LT was administered using the same protocol. In the antrum, LT administration barely modified the EMG signal. However, in the duodenum it prolonged the duration of phase II and the migrating myoelectric complex (MMC) cycle when compared with the control. The number of duodenal MMC cycles was also significantly diminished. Moreover, the migrating velocity of phase III was increased. The migrating action potential complex (MAPC) was present both without and with LT, but occurred more frequently following LT administration. In conclusion, LT caused a dose-dependent, lagged alteration in the duodenal MMC in weaned pigs, involving a reduction of the MMC number by lengthening phase II, increased phase III migration velocity, and increased MAPC frequency. The disturbances did not, however, result in diarrhoea and may reflect the induction of a local protection mechanism of the gut to expel unwanted foreign content from the lumen of the upper gut.

Animals↗

PubMed2004

Effect of sodium butyrate on the small intestine development in neonatal piglets fed [correction of feed] by artificial sow.

Feeding of neonates with artificial milk formulas delays the maturation of the gastrointestinal mucosa. Na-butyrate has a complex trophic effect on the gastrointestinal epithelium in adults. The present study aimed to determine the effect of milk formula supplementation with Na-butyrate on the gut mucosa in neonatal piglets. Sixteen 3 day old piglets were randomly divided into two groups: control (C, n = 8), and Na-butyrate (B, n = 8). Animals were feed for 7 days with artificial milk formula alone (C) or supplemented with Na-butyrate (B). At the 10(th) day of life the piglets were sacrificed and whole thickness samples of the upper gut were taken for analyses. Administration of Na-butyrate led to significant increase in daily body weight gain as compared to control. In the duodenum, the villi length and mucosa thickness were reduced, however, in the distal jejunum and ileum, the crypt depth, villi length and mucosa thickness were increased in Na-butyrate supplemented piglets as compared to control. Supplementation with Na-butyrate did not affect the intestinal brush border enzyme activities but increased plasma pancreatic polypeptide and cholecystokinin concentrations. These results suggest that supplementation with Na-butyrate may enhance the development of jejunal and ileal mucosa in formula-fed piglets.

Animals↗

PubMed2003

Exogenous leptin controls the development of the small intestine in neonatal piglets.

Leptin, a hormone produced and secreted by adipose tIssue, muscles and stomach, is involved in the regulation of adipose tIssue mass, food intake and body weight in neonatal animals. It is also produced in the mammary glands and secreted into the colostrum and milk. Since leptin receptors are widely distributed in the small intestine mucosa, the aim of the present study was to investigate the effect of exogenous leptin on the development of the small intestine in neonatal piglets. Male neonatal piglets were fed with sow's milk or artificial milk formula. Every 8 h the latter received either vehicle or leptin (2 or 10 microg/kg body weight). The animals were either killed after 6 days of treatment and the small intestine sampled for histology and brush border enzyme activities or were tested for marker molecule (Na-fluorescein and BSA) absorption in vivo. Feeding milk formula slowed the maturation of small intestinal mucosa compared with feeding sow's milk. However, after leptin treatment the length of the small intestine was increased, and intestinal villi length, but not crypt size, was reduced compared with controls. The mitotic index was increased and the percentage of vacuolated enterocytes was reduced in the entire small intestine. Enterocyte brush border protease and lactase activities were reduced in the jejunum. Na-fluorescein marker molecule absorption did not change but that of BSA was reduced 3.8-fold. In conclusion, exogenous leptin administered in physiological doses reversed the maturation of the small intestinal mucosa to the range found in sow-reared piglets.

Aminopeptidases↗

PubMed2003

Physiological and chemical characteristics of antibacterial activity of pancreatic juice.

Attempts were made to find and characterize an antibacterial activity (ABA) factor in porcine pancreatic juice (PJ). Its isolation requires several steps. Since ABA factor was found to be heat resistant, the first step was heating for 30 min at 65 degrees C. Afterwards column chromatography, ethanol precipitation and polyacrylamide gel electrophoresis were involved. Finally, we obtained a pancreatic juice fraction with antibacterial activity against Escherichia coli strain AB1157. In the presence of this fraction the number of living bacterial cells in overnight culture decreased about 10,000 fold and a spot-test gave clearly positive results. The results of analysis suggest that the antibacterial factor is a polypeptide active in a pH range 8.0-8.5, that migrates in polyacrylamide gel electrophoresis as a band under 14,000 Da. Mass spectroscopy analysis of active fraction showed high concentration of porcine pancreatic spasmolytic polypeptide (PSP). In conclusion, a polypeptide controlling bacterial homeostasis has been found in the porcine pancreatic juice.

Animals↗

PubMed1988