V. Kukolj

The role of hepatic myofibroblasts in liver cirrhosis in fallow deer (Dama dama) naturally infected with giant liver fluke (Fascioloides magna).

BackgroundThis paper describes liver cirrhosis in 35 fallow deer infected with the giant liver fluke, as well as the distribution, origin, and role of myofibroblasts in its development.ResultsIn liver of infected deer, stripes of connective tissue are wound around groups of degenerated and regenerated liver lobuli. In the connective tissue, lymphocytes and macrophages which often contain parasite hematin are also present. The walls of the bile ducts are thickened, the epithelium multiplied with mucous metaplasia, and desquamated cells, parasite eggs and brown pigment are present in their lumen.In the livers with cirrhosis, immunopositivity to α-SMA and desmin was observed in cells in portal and septal spaces, at the edge between fibrotic septa and the surrounding parenchyma and in perisinusoidal spaces. These cells vary in size, they are round, oval, spindle-shaped or irregular in shape, similar to vascular smooth muscle cells. The derangement of epithelial-mesenchymal interactions detected in chronic cholangiopathies is most probably the pro-fibrogenic mechanism in liver cirrhosis of fallow deer (Dama dama) infected with the giant liver fluke (Fascioloides magna).ConclusionMyofibroblasts, especially hepatic stellate cells (HSCs), play an important role in the synthesis of extracellular matrix components in the development of parasitic fibrosis and cirrhosis in the liver of fallow deer.

An outbreak of fumonisin toxicosis in horses in Serbia

This paper reports on an outbreak of fumonisin toxicosis in a stable with 100 horses. Twenty-one horses were affected and fifteen died within a month. The animals were not febrile and exhibited poor appetite, somnolence, head pressing, blindness, ataxia, lethargy, and seizures, ending with death. The post mortem examination of the head of one 18-month-old colt revealed large, bilateral, slightly asymmetrical large areas of necrosis of the cerebral white matter. The lesions involved the frontal, parietal and occipital lobes only. Histological findings revealed leukomalacia with necrosis, infiltration of macrophages, neutrophils and eosinophils, haemorrhage and oedema of the surrounding grey matter. In response to the pathological findings, which indicated equine leukoencephalomalacia (ELEM), feed samples from the premises were tested for fumonisin B1 and B2 (FB1 and FB2). The milled maize samples contained 6.0 mg/kg FB1 and 2.4 mg/kg FB2, while the maize bran contained 6.05 mg/kg FB1 and 1.68 mg/kg FB2. Th...

Role of hepatic stellate cells (HSCs) in the development of hepatic fibrosis in cats with polycystic kidney disease (PKD).

Hepatic stellate cells (HSCs) play a significant role in hepatic fibrogenesis. In the following study we described the distribution of cells that express alpha-smooth muscle actin (α-SMA) and desmin in the cat liver with various degrees of fibrosis, as well as the significance of hepatic stellate cells and portal myofibroblasts in the genesis of fibrosis in cats with polycistic kidney disease. Liver samples from 15 necropsied Persian cats were examined microscopically, using H&E and Masson-trichrom methods and immunohistology for α-SMA and desmin. Liver fibrosis was confirmed in cats with terminal stage of chronic cholangiohepatitis and it was characterized by connective tissue septa which divide the liver parenchyma into irregular lobuli. Inflammation in the cat liver is connected with the activation of periductal myofibroblasts. The intensity of immunopositivity of perisinusoidal HSCs to α-SMA and desmin varied depending on the degree of fibrosis and was the strongest in livers of cats with cirrhosis.

Expression of α-SMA, desmin and vimentin in canine liver with fibrosis

In this work, 36 canine livers with fibrosis were examined. Based on the degree of fibrosis, the livers were classified into three groups: 1- mild portal fibrosis; 2- moderate portal fibrosis with mild periportal and septal fibrosis; 3- severe portal fibrosis with marked periportal and septal fibrosis or cirrhosis. Normal liver sections obtained from five dogs with no evidence of infectious, neoplastic, or cardiovascular diseases were used as controls. The degree of fibrosis was evaluated on liver sections stained according to Massons trichrome method. It was proved using an immunohistochemical method that HSC and periductal myofibroblasts are immunoreactive to desmin, vimentin and α-SMA. Desmin, vimentin and α-SMA positive cells in the portal triad were significantly more numerous in dogs with fibrosis of the third degree than in the controls or all other examined livers. The density of α- SMA, vimentin and desmin-positive cells in the portal triad was in correlation with the degree of fibrosis, which cannot be said for HSC. These results suggest that portal myofibroblasts have a significant role in the process of liver fibrosis in dogs.

Retrospective study of canine epithelial and melanocytic tumors

Out of the total number of canine tumors examined at the Department of pathology based on biopsy and section materials over the last five years skin tumors and mammary gland tumors were proved to be the two largest groups diagnosed in 33.4% and 36% of cases, respectively. Cutaneous tumors were diagnosed in 211 cases, i.e., in 123 (58.3%) male dogs and 88 (41.7%) bitches, of different breeds, on average 7 years old. Among the total number of 211 skin tumors, 32 types of cutaneous neoplasms were diagnosed, with epithelial and melanocytic tumors being the most predominant, followed by hematopoietic tumors and mesenchymal tumors of the skin and soft tissues. In our bioptic and section materials, epithelial and melanocytic skin tumors were the most frequent -123 cases (58.75%) with four subgroups within the group tumors with adnexal differentiation - 66 cases (53.23% of all epithelial and melanocytic skin tumors), epidermal tumors - 25 cases (20.16% of all epithelial and melanocytic skin tumors), tumors without squamous or adnexal differentiation -16 cases (12.90% of all epithelial and melanocytic skin tumors) and finally melanocytic tumors -14 cases (11.29% of all epithelial and melanocytic skin tumors). The age of dogs with epithelial and melanocytic cutaneous tumors ranged between 5 months to 15 years. The fact that the number of skin tumors diagnosed in 1999 was doubled in 2002 is of particular importance, which may be, the result of increasingly high interest of clinicians for biopsy-based diagnosis.

Influence of phytogenic feed additive on Lawsonia intracellularis infection in pigs

Lawsonia intracellularis is known to cause proliferative enteropathy (PE), one of the economically most important swine diseases with global distribution. Not unlike other enteric diseases, PE is a frequent indication for antibiotic therapy. However, their unjustified use leads to an emerging problem - antimicrobial resistance. Thus, the aim of this research was to assess if a phytogenic additive may replace antibiotics in the control of PE in 144 weaned piglets (72 treated and 72 controls) naturally infected with L. intracellularis. The quantity of L. intracellularis faecal shedding was monitored by real-time polymerase chain reaction (PCR) assay in faecal samples on day 0, 14 and 28, whilst the level of the ileum damage was determined by immunohistochemistry (IHC) assay performed on gut sections. Real-time PCR assay revealed that cycle-threshold (Ct) values in the treatment group increased significantly over time and were higher than in the control. These results indicate that the use of the phytogenic additive decreases the faecal excretion of L. intracellularis both throughout the experiment and in comparison to the control. The expression of the L. intracellularis antigen in IHC assay was lower in treated animals, implying that the additive leads to the decrease in the pathogen quantity in the ileum. Significantly higher feed conversion ratio was recorded in the treatment group. The results indicate that the phytogenic additive may be beneficial in the control of PE, but additional research is necessary to assess its use in various pig categories and define the optimum concentrations.

The role and immunophenotypic characteristics of myofibroblasts in liver of sheep naturally infected with the lancet liver fluke (Dicrocoelium dendriticum).

The main objective of our research was to examine the role and immunophenotypic characteristics of myofibroblasts in sheep liver naturally infected by the lancet liver fluke (Dicrocoelium dendriticum). In the reported study we analyzed liver samples from 20 adult sheep, 14 infected animals and 6 controls. The liver samples were fixed in 10% buffered formalin, and routinely processed and stained using hematoxylin eosin, the periodic acid-Schiff and Masson-Goldner trichrome methods. The immunohistochemical examination was carried out by the streptavidin biotin (LSAB2) method, using antibodies for α-smooth muscle actin (α-SMA), desmin and vimentin. The histopathological examination revealed liver fibrosis in 6 out of 14 (42.9%) analyzed samples, while different forms of cholangitis were observed in the remaining 8 out of 14 (57.1%). The expression of α-SMA was proven in perisinusoidal hepatic stellate cells, portal/septal myofibroblasts, and interface myofibroblasts. The degree of α-SMA expression and the number of α-SMA immunopositive cells were the most intensive in the liver with fibrosis. Desmin expression in all liver samples of infected sheep was confirmed in hepatic stellate cells and smooth muscle cells. The hepatic stellate cells, portal/septal myofibroblasts, and interface myofibroblasts reacted as vimentin positive cells. In the liver without fibrotic changes hepatic stellate cells and smooth muscle cells were desmin positive. The obtained results suggest that all populations of myofibroblasts, especially hepatic stellate cells, play an important role in the increased extracellular matrix formation during parasitic liver fibrosis in sheep naturally infected with D. dendriticum.

Pathomorphological lesions and distribution of viral antigen in birds infected with the pathogenic strain of H5N1 avian influenza virus.

The aim of this study was to determine pathomorphological lesions in the organs of birds infected with H5N1 avian influenza virus, presence and distribution of the viral antigen in tissue samples and the degree of their correlation. Examination was conducted on the carcasses of seven mute swans (Cygnus olor) and one domestic rooster (Gallus gallus domesticus). After necropsy, trachea, lungs, liver, spleen, pancreas, kidney and intestine tissues were sampled for histopathology and immunohistochemical examination. LSmethod and H5N1 avian influenza virus nucleoprotein polyclonal antibodies were used for detecting the viral antigen in the examined tissues. The most frequent gross lesions were hemorrhages and necroses of the pancreas. Major histological lesions were multifocal necroses in the pancreas, liver and spleen, non purulent encephalitis, with neuronal dystrophy and neuronophagia. Viral nucleoprotein was immunohistochemically proven in the pancreas, brain, liver, lungs, and in one swan in the kidney. A high correlation between pathomorphological lesions and distribution of the viral antigen was determined.

Mast cell tumor within a lipoma in a white toy poodle

Uprkos cinjenici da su mastocitomi jedna od najcescih neoplazmi kod pasa, postoji samo jedan objavljeni slucaj mastocitoma u lipomu. U ovom slucaju, kod 11-godisnje ženke toj pudle primeceno je prisustvo dobro ogranicene, pokretne, meko-elasticne mase na lateralnoj strani grudnog kosa. Histopatoloski pregled je pokazao dobro ogranicenu masu koja se sastojala od zrelih adipocita između kojih se nalaze skupine celija sa granuliranom citoplazmom. Bojenjem toluidin plavim je dokazano prisustvo metahromatskih granula u citoplazmi mastocita. Histopatoloske i imunohistohemijske karakteristike ukazale su na to da je ispitani mastocitom niskog stepena maligniteta.

Malignant mast cell tumour within a benign lipoma in a toy poodle

Despite the fact that mast cell tumours (MCT) are one of the most common neoplasms in dogs there is only one published case of MCT within a lipoma. In this case, in 11-years old female toy poodle was observed the presence of a well-demarcated, freely movable, softy mass on the chest. Histological examination showed a well-circumscribed mass consisted of mature adipocytes and multiple foci of round cells with granulated cytoplasm between adipocytes. Toluidine blue staining demonstrated metachromatic granules in the cytoplasm of mast cells.