Angel Vodenicharov

Morphological and immunocytochemical investigations on mast cells in porcine ureter.

Morphological, morphometric, histochemical and immunocytochemical investigations on mast cells, located in the wall of ureter of 8 months aged pigs were performed. Mast cells were found in all three layers of ureteral wall, but their distribution was irregular and the number unequal. It was established that alcian blue (AB)‐positive mast cells were significantly more than toluidine blue (TB)‐positive mast cells. A statistically significant smaller number of both AB and TB‐stained mast cells were observed in the tunica mucosa. The largest number of mast cells was found in the tunica muscularis. In the adventitia, mast cells were higher in number in the main connective tissue than in the connective tissue near the blood vessels. Mast cells stained with TB showed variably expressed γ‐metachromasia, which was best visible in those situated in the lamina propria of the mucosa. The prevailing parts of mast cells, however, were AB‐positive after AB‐safranin staining. This was mostly found in mast cells of the tunica muscularis and in mast cells of perivascular location in the tunica adventitia. Immunocytochemically, mast cells were found to be positive for histamine and vasoactive intestinal polypeptide in the muscle coat, and to histamine in the adventitia, as well. On the basis of obtained results it was presumed that the mast cells in porcine ureter most probably took part not only in keeping of local homeostasis, but played also an important role of mobility of smooth muscle cells in the middle layer of ureter on one hand, and, on the other, in the adventitial blood vessels.

Structural examination of tryptase-, and VIP-positive mast cells in the common bile duct of patients with lithiasis

The morphology of tryptase-, and vasoactive intestinal polypeptide (VIP)-positive mast cells was examined immunohistochemically in 38 common bile ducts collected from patients with secondary chronic cholangitis and varying degrees of inflammatory activity. Mast cells numbers in chronic exacerbated and chronic sclerotic cholangitis were significantly higher as compared with those in controls (72.4 cells/mm2 and 25.2 cells/mm2 vs. 5.9 cells/mm2; p < 0.0001, Students t test). The increased number of tryptase-positive mast cells in chronic exacerbated cholangitis correlated with the severeness of inflammatory infiltration. In cases of chronic exacerbated cholangitis, the increased number of mast cells was detected in conjunction with active fibroplasia. In chronic sclerotic cholangitis mast cells were lower in number as compared with exacerbated cholangitis and were observed in relation with inactive fibrosis. Numerous VIP-positive mast cells were found in all patients with cholangitis. Ultrastructural immunocytochemistry showed tryptase positivity to be localized over either electron-dense or particulate granules with a mean diameter of 0.261+/-0.073 microm or 0.171+/-0.053 microm, respectively. VIP positivity was formed as a finely or coarsely granular pattern over larger electron-dense granules of 0.475+/-0.14 microm in diameter. Tryptase-positive mast cells were located mainly in and around surface and glandular epithelium. The involvement of tryptase- and VIP-positive mast cells in inflammation, fibrosis and epithelial reactions in the common bile duct is discussed.

Basal testosterone concentrations after the application of a slow-release GnRH agonist implant are associated with a loss of response to buserelin, a short-term GnRH agonist, in the tom cat

Slow-release GnRH agonist implants are considered an effective, reversible alternative to surgical castration in male tom cats. Individual differences exist regarding the onset of efficacy and might be delayed in some animals. Single measurements of testosterone (T) might result in basal concentrations also in intact male cats. Consequently, GnRH stimulation tests are performed to measure T increase in intact animals and to differentiate castrated from intact male cats. In this study, five tom cats were treated with a 4.7-mg deslorelin implant and GnRH stimulation tests using buserelin were performed before treatment and at 4-week intervals afterward until Week 20. After the last test in Week 20 all animals were castrated. Four of five animals had basal T after 4 weeks and-in contrast to pretreatment-application of buserelin did not result in any further T increase. In one animal, T was low after implant insertion, but not basal; however, a GnRH stimulation test induced a slight increase of T in Week 8 and 16 only and no response in Weeks 4, 12, and 20. Testicular volume was significantly decreased and penile spines disappeared in all cats. Testicular histology showed mixed atrophy, but also fully elongated spermatids in three of five male cats making infertility questionable. Because of the loss of the stimulatory effect of short-term GnRH application (buserelin), it can be assumed that long-term GnRH agonists also act by some mechanisms of downregulation of pituitary GnRH receptors in the tom cat.

Endothelin-positive Mast Cells in Porcine Renal Artery and Vein

For a first time the endothelin (ET)‐positive mast cells were examined in the wall of kidney renal artery and vein. The specimen’s were collected from six 8‐month‐old Danmark Landrace pigs, immediately after slaughtering. Mast cells immunopositive to ET granules were observed in the wall of both artery and vein. In the renal artery, they were found mostly between the media and the adventitia. Some mast cells were found in the media, next to smooth muscle cells. Relatively few mast cells were found in the intima and between intima and tunica media. In the renal vein a smaller number of mast cells were observed. They showed similar localization as in the renal artery. Immunopositive mast cells were established also close to endothelial cells – mostly between internal elastic membrane and basal membrane of the endothelium. In conclusion, on the basis of obtained results, presumptions for active participation of ET (most probably mainly ET‐1) in the motility of the vessels’ smooth muscle and for stimulation of nitric oxide release from the intimal endothelial cells were made.

S‐100 Protein‐Positive Mast Cells in Canine Paranal Sinus (Sinus paranalis)

The aim of this study was to establish the immunocytochemical expression of S‐100 protein in mast cells, localized in the wall of dogs paranal sinus. Control serial sections were used for immunocytochemical detection of tryptase‐positive mast cells. It was observed that S‐100‐positive cells have the same morphology and localization as the tryptase‐positive mast cells, which indicated that S‐100‐positive cells are most probably mast cells with abilities as dendritic cells. In conclusion, for the first time, the current study gave evidence that mast cells in this organ possess one more function, such as dendritic cells.

NADPH‐d‐Positive Mast Cells in the Canine Paranal Sinus

With 3 figures

Immunohistochemical Study of 3 β-Hydroxysteroid Dehydrogenase in Dog’s Perianal Sinus

In this study, the localization of 3 β‐hydroxysteroid dehydrogenase (3β‐HSD) activity in the wall of canine perianal sinus (PS) was determined. The 3 β‐HSD activity was found out both in the cytoplasm of cells, situated in the propria and forming clusters adjacently to apocrine glands and in the cytoplasm of some epithelial cells in apocrine cells’ glands. The results obtained about the 3 β‐HSD activity allowed us to propose a role of this enzyme in PS development and possibly, in tumourogenesis.

Distribution of ghrelin-positive mast cells in rat stomach

ABSTRACT It is known that the gastrointestinal peptide hormone ghrelin is expressed in human and rodent B lymphocytes, T lymphocytes, monocytes and natural killer cells. However, there are no data about ghrelin expression by mast cells. These facts, as well as the common progenitor cells of mast cells and the above-mentioned immune cells, motivated us to undertake the current work in order to prove that like other granulocytes, rat gastric mast cells are capable of immunohistochemical expression of ghrelin. Gastric wall sections of Wistar rats were studied immunohistochemically for detection of ghrelin and tryptase and histochemically for toluidine blue in order to identify ghrelin-positive mast cells as well as to establish their localization and distribution. Results showed that mast cell granules expressed ghrelin. The ghrelin-positive mast cells were the least numerous as compared to tryptase-positive mast cells and toluidine blue-positive mast cells. Based on the observed expression of ghrelin in granules of mast cells localized in the rat gastric wall, we suggested that this type of cell can be regarded as an important source of ghrelin and suggested that ghrelin may exert different physiological functions, such as regulation of muscular, epithelial and glandular functions.

Distribution of NADPH-diaphorase Positive Ganglionated Plexuses in Porcine Gall Bladder

The distribution and dimensions of nicotinamide adenine dinucleotide phosphate diaphorase (NADPH-d) positive ganglia in the domestic pig’s gall bladder and Ductus cysticus were studied for the first time. It was established that the number of ganglia was highest in the gall bladder’s body, followed by those in the fundus and neck. The lowest number of ganglia was observed in Ductus cysticus. The largest ganglia were localized in the gall bladder’s neck, followed by these in the body and fundus. The highest density of neurons per ganglion was detected in the neck, followed by body and fundus. Their number, however, was the lowest in the ganglia of Ductus cysticus. The largest neurons were established in the gall bladder’s neck. It was concluded that the NADPH-d ganglia as neuronal structures produce nitric oxide, which as a transmitter with neuronal origin most probably is involved in the control of the epithelial secretion and in the function of smooth muscle in the walls of both gall bladder and blood vessels as well.

Liver tryptase-positive mast cells and fibrosis in children with hepatic echinococcosis

The hepatic echinococcosis in children is a serious surgical problem. The aim of this study is to investigate the participation of mast cells in liver inflammatory reactions triggered by echinococcal cysts. Liver biopsy samples were collected from the tissue surrounding the cysts from 16 sick children (11 boys and 5 girls) in the course of abdominal surgery and from 5 controls. Light and ultrastructural immunocytochemistry was performed using monoclonal antibody against tryptase. Light microscopical immunocytochemistry revealed abundance of tryptase-positive (MCT) mast cells in the capsules of the cysts (43.58 cells/mm2). There were also observed greatly increased numbers of mast cells in portal tracts surrounding the cyst, compared to those of control biopsies (26.49 vs. 1.78 cells/mm2, p=0.0009, Mann-Whitney U test). Based on the ultrastructural appearance of tryptase-positive mast cell granules, morphological sings of activation of most of the mast cells were distinguished. In conclusion, we suggest that the accumulated and activated tryptase-positive mast cells in liver tissues surrounding the echinococcal cysts play a crucial role in modulation of the inflammatory liver response and could induce chronic inflammation and fibrogenesis, resulting in serious liver injury such as nonspecific reactive hepatitis.