The Effect of Decreased Portal Blood Flow on the Biliary System Yutaka SAJ~ ABSTRACT: A disturbance in the regional portal blood flow adjacent to the dilated bile duct in the liver is often observed in patients with hepatolithiasis. The effects of this disturbed portal blood flow on the biliary system, with or without cholangitis, were therefore investigated. Young rabbits were divided into the following four groups; (1) controls that had a laparotomy only (n=3), (2) those that had a ligation of the portal branch of the right posterior lobe (RP lobe) (PL) (n=10), (3) those that had tubing inserted into the bile duct through the duodenal papilla (BS) (n=10), and (4) PL + BS (n=10). Despite marked atrophy of the RP lobe, no distinct changes were seen in the biliary systems of groups 1 or 2. In groups 3 and 4, however, infiltration of inflammatory cells and glandular proliferation in the wall of the markedly dilated extrahepatic bile duct (proliferative cholangitis (PC), characteristic to hepatolithiasis) were seen. Findings of PC were also noted in the intrahepatic bile duct of the atrophied RP lobes of these 2 groups. The incidence of PC was 20 per cent in group 3 and 60 per cent in group 4, respectively, but the PC of the intrahepatic bile ducts in group 3 was more localized than in group 4. Goblet cell metaplasia was seen in the epithelial cells of PC. Bacteriologically, bile samples were aseptic in groups 1 and 2, however, samples of bile from groups 3 and 4 were all contaminated with Escherichia coli or Streptococcus Faecalis. The biliary contents of phospholipids, total cholesterol and total bile acid were significantly decreased in groups 3 and 4, when compared with groups I and 2. In conclusion, a disturbance in portal blood flow, accompanied by cholangitis and segmental liver atrophy, may play an important role in the clinical course of hepatolithiasis. KEY WORDS:
hepatolithiasis, portal blood flow, cholangitis
INTRODUCTION
Hepatolithiasis is an essentially benign bi!iary disease commonly seen in people from oriental countries, especiallyJapan and
The First Department of Surgery, Hokkaido University School of Medicine, Sapporo,Japan Reprint requests to: Yutaka Saji, MD, The First Department of Surgery, Hokkaido University School of Medicine, Kita 15 Nishi 7, Kita-ku, Sapporo 060, Japan
China. 1,2 There have been many hypotheses proposed about the lithogenesity in the intrahepatic bile ducts; cholestasis and biliary infection have been widely accepted as playing an important role in the forming of intrahepatic stones. The pathogenesis, however, has not yet been established. Although several methods of treating this disease have been tried, the results are not always satisfactory? A recurrent cholangitis often annoys the patient and is sometimes even lethal.
JAPANESEJOURNALOF SURGERY,VOL.18, No. 5 pp. 558-568, 1988
Volume 18 Number 5
Portal blood flow and the biliary system
The author previously reported an intimate relationship between liver atrophy, deformity of intrahepatic bile ducts and the loss of regional portal blood flow,4 which are c o m m o n clinical findings accompanying hepatolithiasis. In the present study, the effects of disturbed portal blood flow on biliary systems, with or without cholangitis, was experimentally investigated. MATERIALSAND METHODS Male domestic rabbits weighing between 2.0 and 2.5 kg (Hokkaido Experimental Animal Center, Sapporo) were fed with ordinary rabbit chow (CR-3, Clea Japan Inc. Tokyo). Animals were fasted overnight before the treatment but water was given ad libitum. Laparotomy was carried out under an intravenous anesthesia of 20-40 m g / k g of pentobarbital sodium and the peritoneal cavity was entered through a midline incision. The animals were divided into the following four groups according to the operation given: (1) laparotomy only (n----3); (2) ligation of the portal branch (PL) (n=10); (3) canulation into the bile duct through the duodenum to achieve biliary stasis (BS) (n=10); (4) portal
559
branch ligation and canulation into the bile ducts (PL + BS) (n=10). The ligation of the portal branch and intubation into the bile duct was performed as follows. The extrahepatic portion of the portal branch of the right posterior (RP) lobe was isolated in the subserosal layer in order to avoid injury to such adjacent structures as the artery, the bile duct and the lymphatics. The ligation was carried out just proximal to the portal stem, where the distance between the bile duct and the portal vein is greatest (Fig. l-a, b). The branch was doubly ligated and a 4-0 Ticron| suture was used to diminish inflammation and adhesion. A 20G polyethylene tube (cat. no. 7400, Cray Adams, Parsipany, USA) was introduced into the duodenal lumen through a small stab wound made in the posterior wall of the duodenum after Shibata's 5 procedure. The tip of the tube was inserted to as deep as 7 cm into the bile duct through the papilla in order to achieve ~biliary stasis and subsequently, cholangitis. The free end of the tube was then closed and guided outside the peritoneal cavity through a stab wound penetrating the rectus muscle. The tube was fixed to the duodenum with a double purse-string
Fig. 1. a. cholangiogram of a control rabbit, b. portogram of the same rabbit. RP: Right posterior lobe "k: The site of tigation
Jpn. J. Surg. September 1988
Saji
560 suture using 5-0 Ticron| a n d to the rectus muscle with 3-0 silk sutures. T h e duodenal wall around the tube was fixed to the parietal peritoneum with sutures. T h e weight o f the RP lobe was about 20 per cent of that o f the whole liver and even complete atrophy o f the RP lobe was considered to have b r o u g h t about little change in the other lobes.
Analysis of bile and morphological observation T h e animals were killed six or twelve months after the treatments a n d the ftllowing items were examined. 1. Analysis o f the bile. The bile was obtained from the c o m m o n bile duct prior to sacrifice u n d e r intravenous anesthesia. The samples were cultured o n nutrient agar me-
dium to identify bacteria. Phospholipids, total cholesterol a n d total bile acid were enzymatically determined with commercial kits (Phospholipids C HA-Test Wako, Cholesterol HR-Test Wako, Wako Pure Chemical, Osaka, a n d Enzabile 2, Daiichikagaku, Tokyo, respectively). The biochemical values were shown as the m e a n • standard deviation. Statistical analysis was performed using Student's t test for i n d e p e n d e n t sample means. 2. Morphological observation. After the g a l l b l a d d e r was e m p t i e d t h r o u g h a fine needle aspiration, an 18G elaster catheter was inserted into the bile duct through the papilla in exchange for the polyethylene
Table 1. Dilation of Bile Duct Animal No.
Treatment
Duration of CBD Observation
Right Posterior Lobe Central Peripheral
The Other Lobe Central Peripheral
1
14 26 30 34 3 7 24 25 36 59 60 65 66 67 23 48 50 52 53 6 17 18 33 72
6 mos.
4-
--
--
--
4-
--
--
__
4-
--
--
--
-
--
--
--
--
PL 12 mos.
BS
--
6 mos.
4-
-
4-
-
4+
--
4-
-
4+
4+ +
+ --
4+ 4+ +
+ -
~4
4+
4-
+
-
4_
+ + +
44+ +
-
9
+
+
44+
444-
44-
~+ 6 mos.
+~
+~ PL 4- BS 12 mos.
PL, ligation of portal branch; BS, bilestasis 4-: ~ • ~: 2 •
4+ 4+ 4+ 4+ +
4+
4-
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Portal bloodflow and the biliary system
tube. The biliary system was then filled wi(h 50 per cent barium sulphate emulsion. Animals were sacrified with a lethal dose of pentobarbital sodium. The liver was perfused with a drip infusion of 10 per cent buffered formalin solution through the portal vein. The total liver, extrahepatic bile duct and duodenum were removed en bloc and fixed in 10 per cent buffered formalin solution for 48 hours. Cholangiograms were taken with Fuji Computed Radiography (Fuji Medical Systems, Tokyo) or with Senographe 500t (CGR; Compagnie Generale de Radiologie, Paris). The liver and bile duct were sectioned and stained with hematoxylin-eosin (HE), alcian blue (AB), (pH 2.5) and periodic acid-Schiff (PAS).
561
Fig. 2. Cholangiogram of animal no. 36 from group 2, demonstrating marked atrophy of the RP lobe without deformity of the bile ducts (arrow).
RESULTS Gross appearance of the biliary tree Results are summarized in Table 1, by dividing the bile ducts into three parts, namely; (1) the extrahepatic ducts, those proximal to the main lobar ducts; (2) the intrahepatic central ducts, the main lobar ducts and their chief branches; and (3) the intrahepatic peripheral ducts, those distal to the central one. None of the group 1 (control) animals showed dilatation or any other abnormal findings on the cholangiograms. In group 2 (PL), although marked and constant atrophy of the right posterior lobes with deprived portal blood flow was constantly noted, the cholangiograms showed only a slight dilatation of the bile ducts in those lobes (Table 1). The large bile ducts were well maintained, however, the smaller bile ducts were markedly diminished in number (Fig. 2). In group 3 (BS), the extrahepatic bile duct was cylindrically dilated to more t h a n 5 times the normal diameter. In four out of the five animals, the intrahepatic bile ducts showed mild dilatation to within twice the normal size (Fig. 3) but diffuse dilatation of the total biliary tree was found in one animal (no. 66; Fig. 4).
Fig. 3. Cholangiogram of animal no. 67 from group 3, showing diffuse and mild dilatation of the intrahepatic bile ducts. In group 4 (PL + BS), both the extrahepatic and intrahepatic bile ducts, except for those in the right posterior lobe, were dilated as much as those of group 3. T h r e e out of five animals in each subgroup showed marked dilatation of the intrahepatic bile ducts in the RP lobes (Fig. 5). Such remarkable dilatation was not seen in any of the
562
Fig. 4. Cholangiogram of animal no. 66 from group 3, showing diffuse dilatation of the total biliary tree. intrahepatic bile ducts of the group 3 animals or in any of the intrahepatic bile ducts other t h a n those o f the RP lobes o f the group 4 animals (Table 1). T h e tributaries of the dilated bile ducts were relatively narrow, but the size o f the caliber was almost the same as that o f the control group.
Histological findings of the bile ducts Histological examination was p e r f o r m e d with special reference to wall thickening, glandular proliferation a n d infiltration of inflammatory cells into the wall o f the bile ducts (Table 2). T h e grading o f the changes were made according to the m e t h o d o f O h t a et al. 8 T h e most striking observation was the a p p e a r a n c e o f a glandular structure in the walls o f the bile ducts. T h e s e glands w e r e f o u n d in the extrahepatic bile ducts of the group 3 and 4 animals (Fig. 10-a) but were not seen in the animals o f groups 1 or 2. Glandular proliferation was also noted in the 'walls o f the dilated intrahepatic ducts in groups 3 and 4. T h e incidence of intrahepatic glandular proliferation was 60 per
Sail
Jpn. J. Surg. September 1988
Fig. 5. Cholangiogram of animal no. 6 from group 4. Marked dilatation of the bile duct in the RP lobe (-k) and of the extrahepatic bile duct ( , ) can be seen. The intrahepatic bile ducts, however, apart from those in the RP lobe, did not display the same degree of dilation and their configuration was relatively well maintained (arrow). cent in both the six a n d twelve m o n t h subgroups o f group 4. T h e same structure was also noted in one case of group 3, but that seen in group 3 was m o r e localized than t h a t in group 4 (Fig. 6). T h e gland o p e n e d into the l u m e n o f the bile duct through a conduit a n d the cytoplasm of the glands was strongly positive for alcian blue staining, which suggested that the gland secreted acidic m u c o p o l y s a c c h a r i d e . T h e l u m i n a l b o r d e r o f the epithelium was positive for PAS and alcian blue staining (Fig. 7-a, b). As a rule, the glandular proliferation was accompanied by a fibrous thickening of the wall and infiltration o f inflammatory cells. In two cases o f group 2, a thickening o f the intrahepatic bile ducts was noted without cellular infiltration (Fig. 8). In a serial section d o n e on a specimen taken f r o m an animal o f group 4 (Fig. 9), n u m e r o u s glands were observed in the wall of tile c o m m o n duct (Fig. 9-a), while at the
Volume 18 Number 5
Portal bloodflow and the biliary system Table
Animal No.
Treatment
Duration of Observation
Laparotomy
12 mos.
C 1
C2 C3 1 14 26 30
6 mos.
2.
563
Histological F i n d i n g s
Extrahepatic Bile Duct WT GP CI -
-
-.
. .
-. . .
. . .
I n t r a h e p a t i c Bile Duct Right posterior lobe T h e o t h e r lobe WT GP CI WT GP CI
F
.
. .
--
.
.
.
.
.
.
.
. . .
+ . . .
. . .
. . .
.
.
.
. .
.
.
.
.
.
. . . .
.
.
. . . .
. . . .
PL 3
-.
12 mos.
24 25 59 60 65 66 67
BS
6 mos.
-. ~+ 9 9 9 9
--
-
.
+
.
.
.
. .
.
.
+H ~+ 9 ~ -~
+ + + + .
.
.
.
. --. +
.
.
.
.
+ +
-+
.
.
.
+ .
.
.
.
.
.
.
.
_
-.
~+ ~+~ ~+ %
. .
---
--
--
. +
.
---
.
.
23
~+
9
9
~
+
+
+
-
-
48
+~
+~
+~
~
~+
+k
--
--
-
~+ ~ ~+
+~ ~+ ~+
~ ~ ~+
~~+ ~-
-~ ---
~ + +
----
----
----
9 ~ 9 ~+
9 H+ ~ +F
Ht ~ ~ +
~+ + ~
9 +
~+ + + +
--
--
--
--
--
--
~+
+~
q+
+F
q+
~+
--
--
-
6 mos.
50
52 53 6 17 18 83 72
P L + BS
12 mos.
WT, T h i c k e n i n g o f wall; GP, G l a n d u l a r proliferation; CI, Infiltration o f i n f l a m m a t o r y cell r e l a t i v e l y n a r r o w p o r t i o n , c o r r e s p o n d i n g to the end of the segmental duct, besides a t h i c k e n i n g o f t h e wall, n o g l a n d s w e r e n o t e d (Fig. 9-b). T h e g l a n d u l a r s t r u c t u r e p r o l i f e r ated in the wall of the bile ducts in the RP l o b e (Fig. 9-c). G o b l e t c e l l m e t a p l a s i a w a s seen in the biliary epithelium in the RP lobe (Fig. 10), a n d s c a t t e r e d i n t r a e p i t h e l i a l g l a n d s , c o n s i s t i n g o f c o l u m n a r c e l l s w i t h c l e a r cytoplasm, similar to those of the submucosal glands were observed. The course or the histological changes were investigated by comparing the findings of the 6 month subgroups of groups 2 and 4 with those of t h e 12 m o n t h s u b g r o u p s , h o w e v e r , n o r e markable difference could be found.
Bacteriologicalfindings The bile of groups 1 and 2 was almost colourless, however, that of groups 3 and 4 was green, indicating bacterial infection. The e x a m i n e d b i l e s a m p l e s w e r e all a s e p t i c i n groups 1 (n=2) and 2 (n=5), however, in g r o u p 3, all c u l t u r e d s a m p l e s w e r e c o n t a m i n a t e d w i t h Escherichia coli ( n = 3 ) . O r g a n i s m s w e r e a l s o i d e n t i f i e d i n all o f t h e six s a m p l e s i n g r o u p 4; Escherichia coli i n f o u r a n d Streptococcusfaecalis i n two.
Biochemical changes in the bile The biliary contents of phospholipids w e r e s i g n i f i c a n t l y l o w e r i n g r o u p s 3 a n d 4, t h a n i n g r o u p s 1 a n d 2. T h e c o n c e n t r a t i o n o f total cholesterol and total bile acid were also
Saji
564
Jpn. J. Surg. September 1988
Fig. 6. Photomicrograph of the intrahepatic bile ducts in the RP lobe of animal no. 66 from group 3. Two bile ducts of almost the same size can be seen. The duct on the right demonstrates the characteristic appearance of proliferative cholangitis, however, that on the left is free from abnormal changes. (HE, X4.5) decreased in groups 3 a n d 4 (Fig. 11). DISCUSSION Hepatolithiasis is clinically characterized by a deformity o f the intrahepatic bile duct 9 a n d histologically characterized by a proliferation of the mucin producing glands in the thickened wall o f the intrahepatic bile ducts, s T h e m e c h a n i s m o f these changes, however, including w h e t h e r they are con~ genital or acquired, a n d the role o f these changes in the formation o f stones, has not yet b e e n clarified. Cook et al. 2 reported o n 110 cases of recurrent, pyogenic cholangitis, and stated that the Changes in the bile duct b o r e no relation to the existance o f calculi, which suggests that the stones are not a cause, but a result of the certain pathological process. According to Yamamoto, 1~the intrahepatic glandular formation may not be due to inflammation or other acquired causes but rather to congenital factors, although it is difficult to clarify whether the intrahepatic periductal glands are preexisting or newly formed. T h e author a n d coworkers also previously
Fig. 7. Photomicrograph of the wall of the bile duct in the RP lobe of animal no. 6 from group 4. a. Note the glandular proliferation with marked infiltration of inflammatory cells in the thickened wall. (HE, X3) b. Higher magnification shows the cytoplasm of the glands as being strongly positive for alcian blue. The luminal border of the epithelium is positive for alcian blue and periodic acid-Schiff. (AB and PAS, X50) reported that the glands in this disease were regarded as b e i n g congenital structures, u In this study, however, we observed numerous mucin producing glands, very similar to those in clinical cases, in the wall of the dilated intrahepatic bile ducts, where no glands were normally noted in our control study or in the literature? 2 T h e source o f these glands was thus considered. It is possible that they might migrate up from the preexisting glands in the extrahepatic bile ducts, however, we believe that they were newly f o r m e d f r o m the biliary epithelial cells because they are far different
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Portal blood flow and the biliary system
565
Fig. 8. Photomicrograph of the intrahepatic bile duct of the RP lobe obtained from animal no. 3 from group 2. A thickening of the wall without inflammation was demonstrated. (HE, X50)
Fig. 9. Top: Cholangiogram o f animal no. 48 from group 4. The section lines are shown alphabetically. a. Photomicrograph of the wall of the common duct. Glandular proliferation can be seen. (HE, X50) b. The wall of a relatively narrow segment. Note the absence of glandular structure, despite the thickening of the wall. (HE, X50) e; The intrahepatic bile ducts. The triad o f proliferative cholangitis; glandular proliferation, infiltration of inflammatory cells and thickening of the wall are remarkable. (HE, X25)
f r o m n o r m a l l y e x i s t i n g g l a n d s in c o n f i g u r a tion, a n d t h e relatively n a r r o w s e g m e n t s w i t h o u t g l a n d u l a r plZoliferation were o f t e n
Saji
566
Fig. 10. Photomicrograph of the biliary epithelium in the RP lobe obtained from animal no. 48 from group 4, showing the appearance of goblet cells. (HE, X50) located between the dilated intrahepatic and extrahepatic ducts. T h e y seemed to be f o r m e d by way o f goblet cell metaplasia o f the biliary epithelium. Chow and Gibson 1~observed that in rabbit clonorchiasis, the flukes ascended into the larger interlobular ducts, and mucin production was e n h a n c e d there with the formation of deep glands, although it was not normally found at this level. They concluded that the stimulation to the production o f mucin in clonorchiasis was not a specific one and the
Jpn. J. Surg. September 1988 change was possibly due to the long duration of low grade inflammatory changes that the infestation had brought about. Nakanuma 8 suggested that foreign bodies such as flukes and calculi caused glandular proliferation in the wall of the adjacent bile duct. In this study, glandular formation was seen in the wall o f the intrahepatic bile ducts without stones and, considering this observation, glandular formation is possibly not caused by stimulation from foreign bodies. Focal liver atrophy is a c o m m o n complication o f hepatolithiasis 8 and many hypotheses have b e e n made concerning the cause of this atrophy. Rous and Larimore 13 experimentally observed complete local parenchymal atrophy following the occlusion of the regional portal vein. From an analysis o f 32 h u m a n cases with atrophy o f the left hepatic lobes, Benz et al.14 classified them into 5 groups, namely; 1) those in which there was obstruction of the portal vein or o f its branch, 2) those in which there was evidence o f present or previous obstruction of the bile ducts, 3) those in which tfiere was evidence of biliary obstruction and compression o f the left portal vein, 4) those in which severe malnutrition was the
Fig. 11. Biliary lipids (mean + SD). *, p<0.1; **, p<0.05; N.S., not significant PL, ligation of portal branch; BS, bilestasis
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Portal bloodflowmnd the biliary system
outstanding clinicopathological feature, and 5) those in which there were miscellaneous features. Braasch et al. 1~ suggested that chronic obstruction of the segmental ducts caused hypertrophy of the unobstructed lobe and atrophy o f the obstructed lobe, but his coworker ReMine 16 reported later that only 6 out o f 33 patients with chronic obstruction o f the unilateral hepatic duct, demonstrated significant lobar atrophy. He emphasized the significance of arterial injury in addition to the chronic obstruction o f the bile ducts. Microscopically, cholestasis is not a c o m m o n finding in hepatolithiasis. 8 In the present experiments, narrow segments were seen at the tributary of the dilated right posterior lobar ducts and when the orifices o f the ducts were seen from the lumen of the c o m m o n ducts, they had the appearance of pinholes, although the cholangiograms revealed the caliber of those ducts as being n o smaller than the normal size. These clinical and experimental findings strongly suggest that the intrahepatic biliary obstruction itself is not essential in the pathogenesis o f hepatolithiasis. T h e author 4 previously demonstrated the intimate relationship between disturbances in the portal blood flow and focal liver atrophy in 10 cases of hepatolithiasis. Arterial blood flow was relatively well maintained and, in some o f the cases, neovascularity attributable to inflammation was also noted. It is well known that pylethrombophlebitis is not a rare complication accompanying cholangitis, 17 which suggests that obstruction o f the portal vein is more relevant than obstruction o f the artery in the clinical course o f hepatolithiasis. T h e author speculates one possible condition to complete the change o f the bile ducts seen in hepatolithiasis. Recurrent cholangifis causes a disturbance o f the portal blood flow by way o f pylethrombophlebitis, followed by atrophy of the parenchyma and dilatation o f the intrahepatic bile ducts. A resultant decrease in the amount of functional liver mass
567
draining into such dilated bile ducts may cause a proliferation o f the mucin producing glands to maintain the quantity and quality o f the bile. Alternatively, the proliferation may occur to protect the biliary epithelium from bacterial infection by creating this mucous barrier. Either way, it was shown that stones are n o t necess.ary for the course o f proliferative cholangitis a n d that the changes occurring in the bile ducts seem to procede the formation o f calculus. The stone formation might be accelerated by the activation of bacterial enzymes is and by changes in the composition of the bile such as a decreased concentration of lipids. This decrement was mainly attributable to the dilatation o f the bile duct and the subsequent dilution o f the bile. As Yamamoto 1~ reported, mucin producing glands may play an important role in lithogenesis. T h e liver tissue with a decreased portal blood flow can not maintain normal function and is unable to regenerate. T h e dilated bile ducts in the shrunken liver, therefore, would act only as a dead space and be a foci of infection. U n d e r such conditions, the removal o f the dilated ducts by hepatectomy would be the treatment o f choice. T h e author would like to stress, from the results o f this study, the importance o f cholangitis in hepatolithiasis. Cholangitis was experimentally evoked by inserting a catheter through the duodenal papilla. In clinical cases with intrahepatic calculi, the cause o f cholangitis is still unknown, however, the malfunction o f the duodenal papilla seems to play an important role. ACKNOWLEDGMENT
T h e author wishes to express sincere gratitude to ProfessorJunichi Uchino, o f the First Department of Surgery, School o f Medicine, Hokkaido University for his helpful guidance and criticism, to Associate Professor Akira Kakita for his support and encouragement, to Associate Professor Yasunori Fujioka, of the Second Department o f Pathology, School
J. Surg. tember 1988 sJPn.
568
of Medicine, Hokkaido University, for his guidance about pathology and to Dr. Tsuyoshi Takahashi, Dr. Yasuaki Nakajima, Dr. Jun Kimura, Dr. Fumio Katayama and other research members of the First Department of Surgery for their hearty assistance. The author would also like to thank to Miss Yoshiko Fujiya for her help in preparing this manuscript. This study was supported in part by a Research Grant from the Intractable Disease Division, Ministry of Health and Welfare, Japan. (Received for publication on Dec. 9, 1987) REFERENCES 1. Nakayama F, Furusawa T, Nakama T. Hepatolithiasis in Japan: Present status. Am J Surg 1980; 139: 216-220. 2. Cook J, Hou PC, Ho HC, McFadzean AJS. Recurrent pyogenic cholangeitis. BrJ Surg 1954; 42: 188-~203. 3. Sato T, Suzuki N, Takahashi W, Uematsu I. Surgical management of intrahepatic gallstones. Ann Surg 1980; 192: 23-32. 4. Saji Y, Kakita A, Takahashi T, KimuraJ, Tanaka Y, Shiroto H, Takahashi M, Kanbayashi M, Manabe K, Uchino J, Morita Y, Fujioka Y. Angiographic study of hepatolithiasis. Tandoh (1 Jpn Biliary Association) 1988; 2: 9-16. (English Abst.) 5. Ozawa K, Takasan H, Kitamura O, Mizukami T, Kamano T, Takeda H, Ohsawa T, Murata T, Honjo I. Effect of portal ligation on liver mitochondrial metabolism.J Biochem 1971; 70: 755-764. 6. Shibata T. Experimental study on chronic sclerosing papillitis. Nippon Syokakibyo Gakkal Zasshi (JpnJ Gastroenterol) 1986; 83: 1015-1024. (English Abst.)
7. Ohta G, Nakanuma Y, Yamaguchi K. Morphological study of the liver with intrahepatic calculi. '83 Annual report of hepatolithiasis. Research group of hepatolithiasis, Japanese Ministry of Healthy and Welfare 1984; 53-92. (in Japanese) 8. Nakanuma Y, Ohta G, Nagakawa T, Matsubara F. Histological studies on the livers with intrahepatic gallstones. Nippon Syokakibyo Gakkai Zasshi (Jpn J Gastroenterol) 1981; 78: 874-882. (English Abst.) 9. Glenn F, Moody FG. Intrahepatic calculi. Ann Surg 1961; 153: 711-724. 10. Yamamoto K. Intrahepatic periductal glands and their significance in primary intrahepatic lithiasis. J p n J Surg 1982; 12: 163-170. 11. Kakita K, Takahashi T, Kanbayashi M, Matsushita M, Saji Y, Tsuburaya T, Kasai Y. Treatment of intrahepatic stones---A special reference to hepatic resection for the surgical management. I to Choh (Stomach and Intestine) 1984; 19: 419-425. (English Abst.) 12. Chou ST, Gibson JB. The histochemistry of biliary mucins and the changes caused by infestation with clonorchls sinensis.J Path 1970; 101: 185-195. 13. Rous P, Larimore LD. Relation of the portal blood to liver maintenance.J Exp Med 1920; 31: 609-632. 14. Benz EJ, Baggenstoss AH, Wollaeger EE. Atrophy of the left lobe of the liver. AMA Arch Path 1952; 153: 315-330. 15. BraaschJW, Whitcomb FFJr, Watkins EJr, Maguire RR, Kha~ei AM. Segmental obstruction of the bile duct. SGO 1972; 134: 915-920. 16. ReMine SG, Braasch JW, Rossi RU Unilateral hepatic duct obstruction. Am J Surg 1987; 153: 86-90. 17. Ong GB, Chou ST. Recurrent pyogenic cholangifis. In: Kune GA, Sali A, eds. The practice in biliary surgery, Oxford: Blackwell Scientific Publications 1980; 301-316. 18. Maki T. Pathogenesis of calcium billrubinate gallstone: Role ofE. coli,/3-glucuronidase and coagulation by inorganic ions, polyelectrolytes and agitation. Ann Surg 1966; 164: 90-100.
