• Applied Microscopy
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• v.26 no.2
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• pp.207-219
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• 1996

This study was designed to investigate the ultrastructural alterations of the hepatocyte and bile canaliculus of the fasted mice with transmission and scanning electron microscopes. The morphometry was also carried out for the caliber of the bile canaliculus and the number, length and thickness of the microvillus. The hepatocyte observed in the three day fasting group showed ultrastructural images of active function. The dilated bile canaliculi, especially of type II were increased in number as compared with those seen in the normal group. However, the hepatocyte observed in the six day fasting group showed ultrastructural images of inactive function. The bile canaliculi without dilation (type I) were increased in number. The number of microvilli were identical with one another among the different types of bile canaliculi, while their length and thickness were reduced in the dilated bile canaliculi. From the evidence, the luminal size of the bile canaliculi seems to be easily changeable according to the functional state of the hepatocyte. However, the microvilli may not be changed in number but may be changed length and thickness when the bile canaliculi are dilated.

• Parasites, Hosts and Diseases
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• v.51 no.6
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• pp.695-701
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• 2013

Opisthorchis viverrini infection causes inflammation and liver injury leading to periductal fibrosis. Little is known about the pathological alterations in bile canaliculi in opisthorchiasis. This study aimed to investigate bile canalicular alterations in O. viverrini-infected hamsters and to examine the chemopreventive effects of curcumin on such changes. Hamsters were infected with O. viverrini and one group of animals was fed with 1% dietary curcumin supplement. Animals were examined during the acute infection phase, days 21 and 30 post-infection (PI) and chronic infection phase (day 90 PI). Scanning electron microscopy revealed that in the infected group fed with a normal diet, bile canaliculi became slightly tortuous by 30 day PI and more tortuous at day 90 PI. Transmission electron microscopy showed a reduction in microvilli density of canaliculi starting at day 30 PI, with a marked loss of microvilli at day 90 PI. These ultrastructral changes were slightly seen at day 21 PI, which was similar to that found in infected animals fed with 1% curcumin-supplemented diet. Notably, curcumin treatment prevented the reduction of microvilli density, reduced the dilation of bile canaliculi, and decreased the tortuosity of the bile canaliculi relative to non-infected animals on a normal diet at days 30 and 90 PI. These results suggest that curcumin reduces alteration of bile canaliculi and may be a promising agent to prevent the onset of bile duct abnormalities induced by O. viverrini infection.

• Korean Journal of Veterinary Research
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• v.35 no.4
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• pp.659-670
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• 1995

Cyclosporin A extracted from fungus Trichoderma polysporum Rifai and Cyclindrocarpon lucidum Booth serves as an important immunosuppressive drug in transplantation surgery. Systemic treatment with cyclosporin A induces an impairment of the biliary excretion of the bile salts and cholestasis. This study was designed to observe the Ultrastural changes of the hepatocytes and the bile canaliculi in cyclosporin A-induced intrahepatic cholestasis in rats. Cyclosporin A was injected into male Wistar rats intraperitoneally 50mg per kg body weight and rats were necropsied at 1, 3, 6, 9, 12, 24 hours. The liver tissues were observed with transmission and scanning electron microscopes and the results were as follows. Transmission electron microscopy: After cyclosporin A injection, SER and lysosomes were increased in the hepatocytes until 9 hours. At 12 hours after injection of cyclosporin A, RER with dilated cistern were increased, and SER, lysosomes in the cytoplasm were decreased. From 1 hour to 24 hours after injection of cyclosporin A, there were dilation of bile canalliculi and decreased or lost microvilli. At 24 hours the dilation of bile canaliculi were decreased. Scanning electron microsocopy: After cyclosporin A injection, the bile canaliculi were dilated and the microvilli were shortened, decreased or lost according to the sites. At 24 hours, the microvilli packing the bile canaliculi were observed. These observations suggest that cyclosporin A-induced cholestasis is associated with the dilation of bile canaliculi, increased microfilaments of the pericanalicular region and decreased or lost microvilli.

• Applied Microscopy
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• v.29 no.4
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• pp.437-450
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• 1999

Bile canaliculi are the structure delivering bile secreted by hepatocytes into the bile passage. Bile secretion is mainly controlled by the cytoskeletal elements, mainly of actin in the microvilli, pericanalicular web. Most studies on the bile secretion have been done in viva situation, however, to control the various parameters in vitro culture system seem to be more useful. To set up an in vitro experimental system, the investigator isolated hepatocytes with an enzymatic method using a mixture of collagenase and hyaluronidase from normal Sprague-Dawley rat liver and cultured. Isolated hepatocytes were round and formed cords in culture. Microvilli covered the whole surface of hepatocytes. Bile canaliculi were formed between hepatocytes and were characterized by the presence of microvilli of various lengths and shapes mainly arising from small surface mounds. Actin filament core in the microvilli and pericanalicular actin web were incomplete. After cytochalasin D treatment, cultured hepatocytes were round but the surface were irregular with surfacen blebs, folds and grooves. Microvilli on the surface were scarce. Bile canaliculi were markedly dilated often with the detached junctional complexes. Bile canaliculi lacks microvilli almost completely and extended into the pericanalirular cytoplasm showing complex vacuolar and tubular structures by transmission electron mciroscopy. Pericanalicular actin web, intermediate filaments were hardly identified. Subsurface actin filaments were scattered scarcely under the cell membranes. These results suggest that hepatocytes isolated from rats can survive and form bile canaliculi in culture and the actin filaments are involved in the formation and/or maintenance of the bile canaliculi.

• Applied Microscopy
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• v.28 no.2
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• pp.171-180
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• 1998

In the present study, the vacuolar apparatus were investigated in the hepatocytes of rats treated with DA by transmission electron microscopy of conventional and cytochemical thin sections. In the rats after 20 min of dehydrocholic acid treatment, the cis Golgj cisterns were sacculated in line. The saccule occasionally occured by elongation and attenuated neck. The lysosomes also showed protrudent saccule. The vesicles were observed near the cis Golgi cisterns, lysosome and bile canaliculi. Some of the vesicles appeared to be fused to bile canaliculi. The cis Golgi cisterns usually faced toward the bile canaliculi both in normal and experimental groups. The cis Golgi cisterns, protrudent saccule and vesicles were almost devoid of visible contents. The osmium deposits were heavy on the protrudent saccule as well as on the cis Golgi cisterns or on the vesicles isolated near by, but they were light or not observed on the vesicles in the immediate vicinity of bile canaliculi. The acid phosphatase activities appeared on the lysosome and vesicles located near by, but did not appear on the vesicles as approaching closer to the bile canaliculi. The evidence suggests that the vesicles are derived from the cis Gogi cistern and lysosomes and fuse to bile canaliculi for exocytosis, and that the activity in the vesicles is diminished as approaching closer to the bile canaliculi.

• Applied Microscopy
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• v.28 no.1
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• pp.73-82
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• 1998

To elucidate how microfilaments and vesicles participate in bile formation, the pericanalicular cytoplasms were observed in the liver of rats treated with taurocholic acid by deep etching with rapid freezing, and copmpared them with the findings on convensional thin sections. The microfilaments were identified around the bile canaliculi in the forms of core filaments of microvilli, filaments of pericanalicular web running in parallel to the border of bile canaliculi, and filaments on the junctional complex. In taurocholic acid-treated rats, microfilaments could be visualized around the bile canaliculi and along their borders. The microfilaments appeared to be installed to link to both the canalicular membrane and vesicles. Such specialized microfilaments are considered to participate in the translocation of vesicles in the pericanalicular cytoplasm. From the evidence, it is assumed that the microfilament induces the vesicles to transport and fuse to bile canalicull into which bile acids is secreted by exocytosis.

• Applied Microscopy
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• v.27 no.3
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• pp.295-308
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• 1997

Liver tissues were taken from rats 20 min after administration of dehydrocholic acid and biligrafin, fasted for 8 days, and bile duct ligation for 48 hr. And the zonulae occludentes around the bile canaliculi were investigated by the freeze fracture method. In the normal rats, the zonulae occludentes showed networks consisting of one to four strands in many regions. After administration of dehydrocholic acid, the depth of zonulae occludentes were increased and networks consist of six to nine strands. The zonulae occludentes, however, were disorganized, and strands were reduced after administration of biligrafin. In the fasting rats, the zonulae occludentes showed one or two strands which were loosely linked. After ligation of bile duct, the zonulae occludentes were disorganized, and strands were reduced or still in a state not to be reduced. The strands were interrupted by gaps or linear particles in all the groups, especially in the biligrafin and the ligation. The free ends were remarkable in the fasting group and contact or surround the lateral gap junctions in the dehydrocholic acid group. The discontinuities and free ends of strands were also encountered in the normal group, thus suggesting that the barrier is not complete even in the normal state. The aggregation of particles appeared within the meshwork of zonulae occludentes in all the group, except for the ligation. From the evidence, it is assumed that zonulae occludentes are labile, differ in the structure according to the situation of bile canaliculi and show regional alterations even in the same bile canaliculi, that zonulae occludentes are affected by mechanical stress or certain other factors, and that there is a correlation between the strands and particle aggregations in association with the alteration of zonulae occludentes.

• Applied Microscopy
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• v.28 no.1
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• pp.83-90
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• 1998

The pathway of intracellular transport of dehydrocholic acid was investigated in the hepatocytes of rats by transmission electron microscopy with conventional and freeze fracture methods. Both in normal and experimental groups, the cis Golgi cisterns were sacculated and faces toward the bile canaliculus. In the experimental group, however, the cis Golgi cisterns showed buds, which were probably separated to be vesicles. Some of the buds were connected to the cisterns with the narrow neck. The vesicles were increased in the vicinity of bile canaliculi. The fusion between vesicles and bile canaliculus were frequently observed in the experimental group. This was particularly well shown in the freeze fracture replica. In the thin section, the vesicles were devoid of visible contents as seen in the bile canaliculli. The evidence suggests that the vesicles are derived from the cis Gogi cistern in the way that buds pinch off, serve as vehicles to transport dehydrocholic acids and fuse to bile canaliculi for exocytosis.

• Journal of Veterinary Clinics
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• v.8 no.1
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• pp.71-80
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• 1991

Clinical signs, serum chemical values and histological findings of hepatic tissue after partial and complete obstruction of common bile duct in Korean goats were investigated. Abnormal clinical signs were not observed in partial obstruction of common bile duct, but in complete obstruction clinical signs such as jaundice, urine color change, were observed. Serum total bilirubin, total cholesterol, aspartate aminotransferase, sorbitol dehydrogenase, gamma glutamyltranspeptidase, and total protein values increased on the 1-4th day and then gradually decreased to normal level in partial obstruction. However, they tend to increase persistently by the 24th day in complete obstruction of common bileduct. Histologic features of hepatic tissue in partial obstruction were not changed as compared with normal hepatic tissue. On the other hand, in complete obstruction of common bite duct there were moderate bile duct proliferation in a portal area, rupture of bile canaliculi, phagocytosis of bile pigment by Kupffer cells, periportal fibrosis, intrahepatic bile stasis and hepatic cell necrosis.

• Applied Microscopy
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• v.26 no.4
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• pp.465-477
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• 1996

The influence of dehydrocholic acid, cholesterol and phosphstidylcholie to the fine structure of vacuolar apparatus was investigated to better understand the mechanism of intracellular transport of bile constituents in the hepatocytes of rats. The cis Golgi cisterns faced toward the bile canaliculi both in normal and experimental groups. In the hepatocytes from the rats of experimental groups, the primary organic solutes in bile influence the Gogi apparatus, ER and lysosome in the way of increase, cisternal dilation or budding to form the vacuoles. In the dehydrocholic acid group, the cis Golgi cisterns appeared to be sacculated and showed buds, which were probably separated to be vacuoles. Some of the vacuoles appeared to be fused to the bile canaliculi. In the cholesterol and phosphatidylcholine groups, the Golgi cisterns appeared to be dilated and lysosomes were increased in the vicinity of bile canaliculi. The cis Golgi cisterns showing linear saccular fashions were occasonally observed. The increase of lysosomes were more predominant in the cholesterol group. The evidence suggests that dehydrocholic acid is mainly transported through the ER and cis Golgi cisterns, and cholesterol and phosphatidylcholine are mainly transported through the ER and lysosomes via the trans Golgi cisterns, but the cholesterols are frequently transported via the lysosomes.