Light and scanning electron microscopic studies of the extrahepatic bile duct of sheep with experimentally induced Fasciola hepatica infection.

Changes in the common bile duct that contained adult Fasciola hepatica of sheep were evaluated by light (LM) and scanning electron microscopy (SEM). Nine ewes were inoculated with F hepatica metacercariae and necropsied 18 weeks after inoculation. The proximal portion of the common bile duct (CBD) that contained adult flukes was recovered and examined by LM and SEM. The CBD from 2 noninoculated ewes were used for control. On gross examination, CBD were markedly large because of the adult flukes, which were free in the lumen of the ducts. Extensive hemorrhage was not found either in intrahepatic or in extrahepatic bile ducts of any sheep. Histologic examination revealed changes, such as villous hyperplasia and hypertrophy of the epithelium; cell infiltration, predominantly with eosinophils or macrophages; and arterial intimal proliferation. By SEM, the epithelial surface of the CBD appeared intact. Villous hyperplasia and hypertrophy of the epithelium observed by LM was clearly seen by SEM. Epithelial damage, seen as small areas of denuded surface by LM and SEM, was confined to a few areas of the mucosa. Lack of extensive hemorrhage and confined epithelial damage were evaluated relative to the mode of feeding of adult flukes.     

Hematologic and biochemical abnormalities associated with induced extrahepatic bile duct obstruction in the cat

Bile duct obstruction was induced in 6 cats by surgical ligation and transection of the common bile duct. Clinical and laboratory changes were monitored weekly for 25 to 54 days. Clinical signs of obstruction were similar in all cats and included anorexia, pyrexia, lethargy, intermittent vomiting, weight loss, palpable gallbladder, hepatomegaly, and bleeding tendencies. Tissue jaundice and acholic feces were evident grossly as early as postsurgical day (PSD) 4 with a mean onset of jaundice at PSD 5.3 +/- 0.4. Hematologic changes were initially characterized by a mild neutrophilic leukocytosis that increased with the chronicity of bile duct obstruction. Regenerative anemia developed in 4 cats associated with gastrointestinal blood loss. Acute serum biochemical changes were characterized by a marked increase in the mean values of aspartate aminotransferase, alanine aminotransferase, total cholesterol, and copper. Comparatively, only moderate increases in mean serum alkaline phosphatase activity were observed. Mean total bilirubin values increased remarkably at postsurgical week (PSW) 1, reaching a maximal value of 23.1 +/- 4.4 mg/dl at PSW 3 with 71.6 +/- 2.7% direct bilirubin. With chronicity of bile duct obstruction ranging from PSW 3 to PSW 7, the mean serum values of aspartate aminotransferase, alanine aminotransferase, total cholesterol, serum alkaline phosphatase, and total and direct bilirubin stabilized and then declined, whereas the increased mean serum copper values persisted. At PSD 25 to 54, hepatic copper values and serum bile acids were markedly increased. Seemingly, clinicopathologic changes of induced cholestatic hepatic injury depended largely on the duration of biliary obstruction.(ABSTRACT TRUNCATED AT 250 WORDS)     

Light and electron microscopic study of the livers of pregnant mice infected with Listeria monocytogenes.

Listeria monocytogenes cells were observed in the hepatic cell cytoplasm or in the phagosome at 24 and 48 hours but not at 72 hours after inoculation in pregnant mice. The presence of bacteria initially in a membrane-bound vesicle indicates that the bacteria enter the hepatic cells by endocytosis, resulting in eventual destruction of hepatic cells. Characteristic lesions of the liver at 24 and 48 hours after inoculation consist of multiple focal areas of necrosis. The initial neutrophilic reaction seems to give way to a mononuclear reaction (listeriomas) at 72 hours after inoculation. Dilation of rough endoplasmic reticulum and release of many of the bound ribosomes with a relative increase in the number of free ribosomes was observed. Hepatic lesions were not observed in control (nonpregnant) mice.     

Adenocarcinoma of the extrahepatic bile duct in a cat

A scirrhous adenocarcinoma of the extrahepatic bile duct was shown by histopathological examination to be the cause of obstructive jaundice in an 11-year-old female Siamese cat. In addition to icterus, the cat's clinical signs included depression, anorexia, vomiting, constipation, weight loss and dehydration. Symptomatic therapy relieved the anorexia, constipation, dehydration and depression, but jaundice, weight loss and occasional vomiting continued during the 2-month course of illness. Serum cholesterol and serum glutamic pyruvic transaminase (SGPT) remained elevated and serum bilirubin and serum alkaline phosphatase (SAP) values progressively increased from the cat's initial presentation to its death 2 months later. At necropsy the tumour was found to involve only the extrahepatic bile duct. Neoplasia of the extrahepatic biliary system has been reported only twice in domesticated animals (Patnaik et al., 1975; Feldman, Strafuss & Gabbert, 1976).     

Pathogenesis and outcome of extrahepatic biliary obstruction in cats

Extrahepatic biliary obstruction (EHBO) was confirmed at surgery or necropsy in 22 cats. Biliary or pancreatic adenocarcinoma was diagnosed by histopathology in six cats and one cat had an undiagnosed mass in the common bile duct. The remaining 15 cats had at least one of a complex of inflammatory diseases including pancreatitis, cholangiohepatitis, cholelithiasis and cholecystitis. The most common clinical signs were jaundice, anorexia, lethargy, weight loss and vomiting. Hyperbilirubinaemia was present in all cases. Distension of the common bile duct and gall bladder was the most commonly observed finding on abdominal ultrasound. Nineteen cats underwent exploratory laparotomy for biliary decompression and diversion. Mortality in cats with underlying neoplasia was 100 per cent and, in those with non-neoplastic lesions, was 40 per cent. Long-term complications, in those that survived, included recurrence of cholangiohepatitis, chronic weight loss and recurrence of obstruction. Based on these findings, the prognosis for EHBO in cats must be considered guarded.     

Papillary adenocarcinoma of the extrahepatic bile duct in a Holstein cow

A 15-year-old female Holstein cow was presented with a history of anorexia and weight loss. Abnormal physical examination findings included poor body condition, dehydration, icterus, and photodermatitis on nonpigmented areas of the skin of the dorsum. At necropsy, the common bile duct was greatly enlarged, with thickened walls, and tightly adhered to the hepatic capsular surface and serosa of adjacent loops of the small intestine. Two sessile, yellowish, friable, well-circumscribed, cauliflower-like, bulging masses (14 and 8 cm in diameter) were attached to the inner surface of the common bile duct blocking its lumen. Microscopically, the tumor was composed of well-differentiated, columnar epithelial cells with oval or round, vesicular, basal nuclei arranged in papillary projections. Periodic acid-Schiff-positive material accumulated in the apical cytoplasm of the neoplastic cells. Immunostaining of the tumor cells was positive for cytokeratin (CK) of wide-spectrum screening and for CK 7. The diagnosis of papillary adenocarcinoma of the extrahepatic bile duct was based on the morphologic features of the neoplasm and evidence of local invasion. To the best of our knowledge, extrahepatic bile duct carcinomas have not been described in cattle.     

Light and electron microscopic changes in cardiac and skeletal muscle of sheep with experimental monensin toxicosis

Monensin toxicosis was induced in lambs by either a single oral dose of 12 mg/kg or six daily doses of 8 mg/kg. Clinical signs of toxicosis consisted of depression, dyspnea, stiffness of gait, reluctance to move, and recumbency. Serum creatine phosphokinase activity was increased. Samples of skeletal and cardiac muscle were obtained over a six-day period and examined by light and electron microscopy. Light microscopic changes in cardiac and skeletal muscles consisted initially of vacuolation and intracellular edema of muscle cells followed by segmental necrosis. Interstitial fibrosis was present on days 5 and 6 postexposure. Muscle fiber necrosis was more severe in skeletal than cardiac muscles and most severe in sheep given 8 mg/kg of monensin daily. Macrophages were seen only in areas of severe necrosis. The earliest ultrastructural change was severe swelling of mitochondria. Secondary changes consisted of lipid accumulation and myofibrillar alterations. Myoblast proliferation was present as early as four days after initial exposure to monensin.     

Treatment of pancreatitis-associated extrahepatic biliary tract obstruction by choledochal stenting in seven cats

OBJECTIVES: To report the clinicopathological findings and outcome in cats with pancreatitis-associated extrahepatic biliary tract obstruction (EHBO) treated by choledochal tube stenting. METHODS: Medical records of cats with EHBO secondary to pancreatitis that underwent choledochal stenting were reviewed. Information on outcome was obtained by re-examination of the cat or by telephone interview with the owners. RESULTS: All cats had pancreatitis confirmed by histopathological examination of biopsy samples (n=6) or suspected based on gross examination at surgery (n=1). In six cats, a section of 3.5 to five French gauge red rubber catheter and in one cat a section of 22 G intravenous catheter were used as a choledochal stent. Two cats developed re-obstruction of the biliary tract within a week of the original surgery. One cat had confirmed episodes of ascending cholangitis postoperatively. Two cats had chronic intermittent vomiting in the postoperative period. Two cats died during the perioperative period. Five cats survived to discharge, three of which died seven to 24 months postoperatively and two of which remain alive to date. CLINICAL SIGNIFICANCE: Choledochal stenting is an alternative to biliary diversion for management of feline pancreatitis-associated EHBO in select cases. However, there may be greater morbidity with this technique in cats compared with dogs.     

Choledochotomy and primary repair of extrahepatic biliary duct rupture in seven dogs and two cats

Objective : To report clinical findings and outcome in dogs and cats undergoing choledochotomy or primary repair of extrahepatic biliary duct rupture. Methods : Retrospective study of dogs (n=7) and cats (n=2) that had choledochotomy or primary bile duct repair. Results : Extrahepatic biliary obstruction was confirmed at surgery in all cases. The underlying cause in four dogs and both cats was choledocholithiasis, two dogs had gall bladder mucocoeles with associated bile duct rupture, and one dog had inspissated bile obstructing the bile duct secondary to gall bladder carcinoid tumour. Three dogs and both cats had choledochotomies performed to relieve extrahepatic biliary obstruction, and four dogs with bile duct rupture underwent primary repair of the defect. One dog with a bile duct rupture was re‐explored four days postoperatively and had suffered dehiscence of the repair; this rupture was re‐repaired. All animals were discharged from the hospital, and did not have clinical recurrence of extrahepatic biliary obstruction. Clinical Significance : Choledochotomy and primary repair of extrahepatic biliary duct rupture were associated with low perioperative morbidity and no mortality in this small cohort of cases. These techniques are reasonable options either alone or in conjunction with other procedures when bile duct patency cannot be re‐established by catheterisation or bile duct discontinuity exists.     

Cholecystography and cholecystoduodenostomy in the diagnosis and treatment of bile duct obstruction in a dog

A common bile duct obstruction was documented in a dog, by performing cholecystography haparoscopic visualization facilitated performance of the cholecystography. Target cells were a consistent hematologic finding. Cholecystoduodenostomy, an easily performed surgical technique, allowed for restoration of bile flow and resolution of clinical signs.     

Pancreatic duct obstruction in the pig: electron microscopy of chronic pancreatitis

Ultrastructural alterations of pancreatic tissues in growing pigs caused by surgical ligation of the main pancreatic duct are described. Five animals aged 6 to 7 weeks were operated on and necropsied 2, 6 or 8 weeks later. In addition, 3 pigs that were sham-operated served as controls. Obstruction of the ducts caused progressive luminal dilatations and rupture of intercellular connections of the epithelium followed by destruction and atrophy of acinar parenchyma and proliferations of immature ductular epithelial cells free from zymogen granules.     

Light and electron microscopic studies on mast cells of the bovine oviduct

This study was conducted to determine the staining properties, the light and electron microscopic appearance and numerical distribution of mast cells from different regions of the bovine oviduct during the estrous phase and luteal phase. Ten oviducts from bovines in the estrous phase, and 10 from bovines in the luteal phase were used as study samples. In three regions of the oviduct (infundibulum, ampulla, isthmus), mast cells that showed metachromasia with toluidin blue and Ab(+), SO(-) with the combined Ab/SO stains were encountered. Electron microscopic studies of the mast cells showed them to contain two types of granules; a dense homogeneous type and a tiny particulate type. In all three regions of the oviduct, the luteal phase was observed to have a higher number of mast cells per mm2 area than the estrual phase with the isthmus having the most dense population.     

Common bile duct obstruction due to a duodenal gastrinoma in a dog

In dogs gastrinomas are rare endocrine neoplasms that have always been reported to arise from the pancreas. We report here what we believe to be the first case of a duodenal gastrinoma in a dog. A nine-year-old, male, Pekinese dog was presented with a three-day history of anorexia, vomiting and mucous diarrhoea. Clinical examination and laboratory findings suggested the presence of a severe hepatobiliary disorder. Abdominal ultrasonography showed a diffuse increase in echogenicity of the liver, with severe gallbladder dilation and marked dilation of the cystic duct, common bile duct and extrahepatic bile ducts. Based on these findings, an extrahepatic biliary tract obstruction (EBTO) of unknown cause was suspected. At laparotomy, the gallbladder and the extrahepatic bile ducts appeared severely dilated. The gallbladder was tense and could not be compressed suggesting an outflow obstruction. The duodenum at the level of the common duct orifice appeared slightly thickened and severely hardened for a length of 1 cm. Biopsies from the duodenum and liver were obtained and a cholecystoduodenostomy was performed. The duodenal biopsy revealed severe fibrosis of the submucosa and a infiltrate of small pockets and cords of round to polygonal cells with granular cytoplasm. Based on this appearance the differential diagnoses included neuroendocrine tumours and poorly differentiated carcinoma. Despite surgery and supportive therapy the dog continued to be anorexic and to vomit 3-6 times daily. After euthanasia and necropsy, histopathology showed the presence of a neuroendocrine neoplasia involving the duodenal wall with focal invasion of the adjacent pancreas and small liver metastases. On immunohistochemistry, the cytoplasm of approximately 90% of neoplastic cells intensely expressed neuron specific enolase and gastrin. These findings were consistent with a diagnosis of gastrinoma.     

Blastocyst implantation in the domestic cat. Light and electron microscopic study]

Blastocyst implantation in the domestic cat A light and electronmicroscopic investigation Implantation in the cat begins 121/2 days post coitum and lasts to the 14th day. Several hours before implantation begins the extraembryonic trophoblast, in what could be considered a precontact or sensitization phase, shows fine structural evidence of secretory activity. The uterine epithelium at the same times gives evidence of being at first resorptive and, after a differentiation, of being secretory. Secretion also in the gland epithelium can be observed. The attachment of the embryo to the endometrium begins with an appositional phase. The trophoblast is now distinctly resorptive and forms with the uterine epithelium microvilli-free areas of contact lying between the openings of the uterine glands. Then follows an adhesion phase during which additional junctional complexes are formed between an actively proliferating trophoblast and the uterine epithelium which shows now symplasmic differentiation. Finally, in the intrusion phase the uterine epithelium completely disintegrates. In this manner the syncytiotrophoblast which differentiates from the cytotrophoblast invades the maternal tissues until it reaches the endothelium of the uterine blood vessels.     

Light and scanning electron microscopic studies of the nasal turbinates of the horse

The nasal turbinates of 5 young horses were studied by light and scanning electron-microscopy. Stratified cuboidal epithelium lined the rostral part of the dorsal and ventral nasal turbinates of the vestibular region. The polyangular microvillus cells of this region were separated by linear depressions. The mid and caudal parts of the dorsal and ventral nasal turbinates and the rostral part of the ethmoturbinates were lined by pseudostratified columnar ciliated respiratory epithelium. Numerous cilia with dilated blebs on the ciliated cells concealed adjacent non-ciliated supporting cells and goblet cells. The olfactory zone consisting of the olfactory vesicle and a dense network of olfactory cilia localized to the caudal part of the ethmoturbinates. The three regions were delineated from each other by transitional zones.