CM1, a possible novel activation molecule on human lymphocytes

CM1 (centrocyte/-blast marker 1) defined by a mAb developed against concanavalin-A activated PBMC, is expressed specifically on some tonsillar germinal center (GC) B cells. In single flow cytometric analysis, the bone marrow did not express these molecules nor did the PBMC or the thymocytes. The peripheral B lymphocytes showed more than 90% positive, while the peripheral T lymphocytes showed approximately 60% positive at 48 h after activation by PMA/ionomycin, respectively. A western blot analysis and an immunoprecipitation for CM1 showed a band at 70 kDa. Cross-linking of CM1 with anti-CM1 mAb induced apoptosis of the GC B cells (CD38(+)IgD(-)). Immunohistochemical staining revealed that the CM1 molecule is distributed over the entire area except the proximal dark zone of the tonsillar germinal centers. These results suggest that the CM1 molecule might be involved in differentiation of the germinal center B cells as one of the novel centrocyte markers.

Epstein-Barr virus in gastric carcinomas with lymphoid stroma

AIMS

To clarify the relationship between the Epstein-Barr virus (EBV) and gastric carcinoma with lymphoid stroma (GCLS) in Koreans, and to characterize the EBV-positive GCLS.

METHODS AND RESULTS

EBV infection was examined using EBER in-situ hybridization and polymerase chain reaction in 45 cases of GCLS among Koreans, and in 292 consecutive cases of gastric carcinomas without lymphoid stroma (non-GCLS) as controls. EBV infection was found in 30 tumours (67%) of GCLS and 10 tumours (3.4%) of non-GCLS (P < 0.05). EBV-positive GCLS was more prevalent in males, poorly differentiated histological type and diffuse type in Lauren's classification, and tended to be located more in the middle third of the stomach than EBV-negative GCLS (P < 0.05). p53 overexpression was observed in 22% of GCLS (17% of EBV-positive GCLS and 33% of EBV-negative GCLS), and 34% of non-GCLS (EBV-positive GCLS vs. non-GCLS: P = 0.056). The survival of the patient with GCLS was not correlated with EBV infection or p53 immunoexpression (follow-up period: 11-97 months).

CONCLUSIONS

GCLS in Koreans is strongly associated with EBV infection. The prognosis in GCLS is not dependent upon either the status of EBV infection or the status of p53 immunoexpression.

Effects of dietary folate on intestinal tumorigenesis in the apcMin mouse

Dietary folate appears to be inversely related to colorectal cancer risk. This study investigated the effects of dietary intervention with folate or the development of intestinal polyps in Min (Apc +/-) mice. Weanling Mil mice were fed diets containing 0, 2 (basal requirement), 8, or 20 mg folate/kg diet. At 3 and 6 months of dietary intervention, 50% of the mice from each group were sacrificed, and the small intestine and colon were analyzed for polyps and aberrant crypt foci (ACF). Serum folate concentrations accurately reflected dietary folate levels (P < 0.001). At 3 months no significant difference in the average number of total small intestinal polyps was observed among the four groups. However, increasing dietary folate levels significantly reduced the number of ileal, but not duodenal or jejunal, polyps in a dose-dependent manner (P-trend = 0.001); folate supplementation at 20 mg/kg diet was associated with a 68-78% reduction in the number of ileal polyps compared with the other three diets (P < 0.007). The number of ileal polyps was inversely correlated with serum folate concentrations (P = 0.03). At 3 months, increasing dietary folate levels significantly decreased the number of colonic ACF in a dose-dependent manner (P = 0.05); the control and two folate supplemented diets significantly reduced the number of colonic ACF by 75 100% compared with the folate-deficient diet (P < 0.04). The number of colonic ACF was inversely correlated with serum folate concentration (P = 0.05). No significant difference in the number of colonic adenoma was observed among the four groups at 3 months. At 6 months, no significant differences in the average number of total small intestinal, duodenal, and jejunal polyps, colonic adenomas, and colonic ACF wer observed among the four groups. However, the folate-deficient diet had 62-76% lower number of ileal polyps compared with the control and two folate-supplemented diets (P < 0.003). Serum folate concentrations, but not dietary folate levels, were directly correlated with the number of ilea polyps (P = 0.006). These data suggest that dietary folate supplementation suppresses the development of ileal polyps and colonic ACF in this model However, at later time points, folate supplementation appears to have an opposite effect on ileal polyps. These data generally support the role of folate in intestinal tumorigenesis suggested in epidemiological studies and chemical carcinogen animal models. Notwithstanding the limitations associated with this model, these data suggest that the optimal timing and dose of folate intervention need to be determined for safe and effective folate chemoprevention.

Microsatellite instability and alteration of E2F-4 gene in adenosquamous and squamous cell carcinomas of the stomach

Microsatellite instability (MSI) due to defective DNA mismatch repair (MMR) is a form of genomic instability underlying the tumorigenesis of various human neoplasms. To evaluate the roles of MSI in the pathogenesis of gastric carcinomas with squamous differentiation, 17 primary stomach cancer patients (15 adenosquamous and two squamous cell carcinomas) were examined for MSI frequency using five microsatellite markers and the criteria for MSI recommended by the National Cancer Institute Workshop. The molecular causes and consequences of MSI in these neoplasms were further researched through the immunohistochemistry of MMR proteins and the mutational analysis of cancer-associated genes targeted by MSI, respectively. Two of the 17 (12%) cases demonstrated MSI at the most examined loci and were classified as having high level MSI (MSI-H). These tumors also exhibited frame-shift mutations at mononucleotide repeats in the target genes, including TGFbetaRII, IGFIIR, BAX, and hMSH6. It is interesting to note that the mutations of the serine (AGC)13 repeats within the E2F-4 gene were found only in the squamous cell carcinoma portions of them, whereas such alterations were not detected in any of the adenocarcinomatous portions. This suggests that E2F-4 might be implicated in the transformation of adenocarcinoma into squamous cell carcinoma and further studies are needed to understand its role in squamous differentiation.

Hypotonic swelling increases L-type calcium current in smooth muscle cells of the human stomach

The purpose of the present study was to characterize the Ca2+ channels in smooth muscle cells from human stomach and to examine the effects of osmotic swelling on the channel activity. Ca2+ channel current with either Ca2+ or Ba2+ as charge carrier was recorded from freshly isolated smooth muscle cells using the conventional whole-cell patch clamp technique. The degree of cell swelling as a result of hypotonic challenge was monitored using a video image analysis system. The changes in intracellular Ca2+ concentration ([Ca2+]i) were measured by microfluorimetry. The pharmacological and voltage activation profile suggests a typical dihydropyridine-sensitive L-type Ca2+ current. Cell swelling, induced by hypotonic challenge, enhanced the amplitude of currents through L-type Ca2+ channels without significant effects on steady-state voltage dependency. After treatment with the L-type Ca2+ channel agonist Bay K 8644 (0.1-2 microM), no further significant increase in calcium channel current or corresponding [Ca2+]i transients were provoked by the swelling. The above results demonstrated that the presence of L-type Ca2+ current in smooth muscle cells of the human stomach and the augmentation of the current are closely associated with the volume increase resulting from hypotonic swelling.

Loss of heterozygosity in gastric neuroendocrine tumor

The MEN1 gene locus is known to be partly responsible for the tumorigenesis of sporadic gastric neuroendocrine tumors, but the genetic events that drive the neoplastic process of this tumor remain largely unknown. In order to screen the tumor suppressor genes associated with the tumorigenesis of gastric neuroendocrine tumors, 15 neuroendocrine carcinomas and three carcinoid tumors in the stomach were analyzed for loss of heterozygosity (LOH) using 22 microsatellite markers. In our study, the gastric neuroendocrine tumors showed a high rate of LOH in chromosomes 8p (82%), 15q (58%), 17p (57%), llp (50%), 12p (50%) and 13q (50%). The mean fractional allelic loss (FAL) was higher in the neuroendocrine carcinoma components than in the adenocarcinoma components (0.42 versus 0.33, respectively). In four cases, the adenocarcinoma components showed discordant LOH patterns from those of the neuroendocrine counterparts in half of the informative chromosomes analyzed. Comparably, the gastric neuroendocrine carcinomas exhibited a higher LOH frequency on 8p and a lower LOH on 7q than did the gastric adenocarcinomas. It is suggested that chromosome 8p is the possible location of the tumor suppressor genes associated with the tumorigenesis of gastric neuroendocrine tumors.

Effect of ginsenosides, active components of ginseng, on capsaicin-induced pain-related behavior

Our recent study demonstrated that ginsenosides had antinociceptive effects by reducing some types of pain-related behavior in mice (Yoon et al., 1998. Ginsenosides induce differential antinociception and inhibit substance P-induced nociceptive response in mice. Life Science 62, PL319-PL325). In the present study we further investigated whether ginsenosides produce antinociceptive effects through an action at central or peripheral site(s) and whether these effects are mediated by the opioid system. Intraperitoneally injected ginsenosides suppressed in a dose-dependent manner the pain-related behavior produced by capsaicin injection into the plantar surface of the hind paw; the ED(50) was 49 mg/kg [26-92 mg/kg, 95% confidence interval (C.I.)]. Intrathecally or intracerebroventricularly administered ginsenosides also suppressed the capsaicin-induced pain-related behavior in a dose-dependent manner; the ED(50)s were 1.72 mg/kg (0.8-3.72 mg/kg, 95% C.I.) and 1. 48 mg/kg (0.8-2.6 mg/kg, 95% C.I.), respectively. On the other hand, subcutaneously injected ginsenosides to the plantar surface prior to the capsaicin injection did not alter the pain-related behavior. Naloxone pretreatment was without effect in blocking the antinociceptive effect of intrathecally administered ginsenosides. Intraperitoneally injected ginsenosides also did not significantly affect the motor response of animals. These results suggest that ginsenosides produce antinociceptive effects through their action at the spinal and/or supraspinal site(s), not at nociceptors in the periphery. In addition, the results suggest that the antinociceptive effects are not mediated by opioid receptors.

Genetic alterations in gastric cancer cell lines and their original tissues

To investigate the genetic changes that occur during establishment of gastric cancer cell lines, 4 gastric cancer cell lines and their original tumor tissues were examined for microsatellite instability (MSI), loss of heterozygosity (LOH), and p53 mutation. MSI status did not change during the establishment, though the cell lines gained frameshift mutation in some of the genes with polytract coding sequences. There was no difference in p53 mutation between the cell lines and the original tumors. The frequency of LOH was similar between the cell lines and each original tumor, in the range 30.8% to 85.7%. The difference in the LOH results between the cell lines and the original tumors was not greater than the difference between the different areas of the original tumors. The above results suggested that most of the genetic alterations, such as MSI, LOH, and p53 gene mutation, were sustained during the establishment of gastric cancer cell lines. Minor genetic differences between original tumor tissues and cancer cell lines could be explained as a tumor heterogeneity because separate areas of the original tumor tissues manifest similar variations.

Clinicopathologic study of Castleman's disease in Korea

Castleman's disease represents an atypical lymphoproliferative disorder, infrequently associated with various immunologic abnormalities or subsequent development of malignancy such as Kaposi sarcoma, malignant lymphoma and plasmacytoma. Its clinicopathologic features depend on various etiologic factors such as Kaposi sarcoma herpesvirus (KSHV), oversecretion of IL-6, adhesion molecule and follicular dendritic cell dysplasia, etc. To investigate the relationship of Castleman's disease (CD) and the above factors, we reviewed 22 cases of CD. Four cases of KSHV positive CD were detected, all multicentric, plasma cell type, and these cases displayed prominent vascular proliferation, characteristic 'Kaposi-like lesion'. IL-6 and CD54 positive mononuclear cells were scattered in interfollicular areas of KSHV positive cases. Follicular dendritic cell hyperplasia, vascular proliferation, expression of IL-6 and CD54 did not show any significant difference between solitary vs multicentric type, and plasma cell type vs hyaline vascular type. Our study suggests that KSHV positive CD reveals unique pathologic features, and the probable relationship of KSHV and IL-6 and CD54 is discussed.

The Vienna classification of gastrointestinal epithelial neoplasia

BACKGROUND

Use of the conventional Western and Japanese classification systems of gastrointestinal epithelial neoplasia results in large differences among pathologists in the diagnosis of oesophageal, gastric, and colorectal neoplastic lesions.

AIM

To develop common worldwide terminology for gastrointestinal epithelial neoplasia.

METHODS

Thirty one pathologists from 12 countries reviewed 35 gastric, 20 colorectal, and 21 oesophageal biopsy and resection specimens. The extent of diagnostic agreement between those with Western and Japanese viewpoints was assessed by kappa statistics. The pathologists met in Vienna to discuss the results and to develop a new consensus terminology.

RESULTS

The large differences between the conventional Western and Japanese diagnoses were confirmed (percentage of specimens for which there was agreement and kappa values: 37% and 0.16 for gastric; 45% and 0.27 for colorectal; and 14% and 0.01 for oesophageal lesions). There was much better agreement among pathologists (71% and 0.55 for gastric; 65% and 0.47 for colorectal; and 62% and 0.31 for oesophageal lesions) when the original assessments of the specimens were regrouped into the categories of the proposed Vienna classification of gastrointestinal epithelial neoplasia: (1) negative for neoplasia/dysplasia, (2) indefinite for neoplasia/dysplasia, (3) non-invasive low grade neoplasia (low grade adenoma/dysplasia), (4) non-invasive high grade neoplasia (high grade adenoma/dysplasia, non-invasive carcinoma and suspicion of invasive carcinoma), and (5) invasive neoplasia (intramucosal carcinoma, submucosal carcinoma or beyond).

CONCLUSION

The differences between Western and Japanese pathologists in the diagnostic classification of gastrointestinal epithelial neoplastic lesions can be resolved largely by adopting the proposed terminology, which is based on cytological and architectural severity and invasion status.

Tissue oxygen pressure during prolonged ischemia of the liver

BACKGROUND

The potential role of hepatovenous back-perfusion in maintaining organ viability of the inflow-occluded liver has been reported with respect to aspects of tissue perfusion and energy metabolism. In the present study, the physiological differences between liver ischemia induced by portal triad clamping (PTC) and that induced by total hepatic vascular exclusion (THVE) were investigated in a porcine disease model, with special reference to changes in tissue oxygen pressure (PtO(2)) of the liver.

MATERIALS AND METHODS

Twelve female pigs were used for induction of 60 min of normothermic liver ischemia. They were assigned to two groups: a PTC group (n = 6) and a THVE group (n = 6). PtO(2) was measured before, during, and after the ischemic period at two different points in the middle lobe: on the central side close to the hepatovenous confluence and on the peripheral side close to the gallbladder bed.

RESULTS

Although central PtO(2) decreased during ischemia in both groups, PTC group values at 40 and 60 min of ischemia remained significantly higher than THVE group values (60 +/- 28 and 42 +/- 21 mmHg vs 11 +/- 5 and 13 +/- 3 mmHg, respectively; means +/- SD). Peripheral PtO(2) in the PTC group during ischemia was low in comparison to corresponding central PtO(2) values.

CONCLUSION

Oxygen supply to the tissue via hepatovenous reflux may contribute to maintaining organ viability under prolonged inflow occlusion of the liver.

Hamartomatous gastric polyposis in a patient with tuberous sclerosis

A 42-year-old female diagnosed with tuberous sclerosis was found to have multiple polyps in the fundus of stomach. On histologic examination, the lesions were hamartomatous polyps. In tuberous sclerosis, many lesions occur in multiple organs and there are several reports about the frequent association of hamartomatous polyps of the colon. However, gastric manifestation of tuberous sclerosis has not been established probably due to its asymptomatic nature. This is the first report of multiple gastric hamartomatous polyposis in patient with tuberous sclerosis.

The Vienna classification of gastrointestinal epithelial neoplasia

BACKGROUND

Use of the conventional Western and Japanese classification systems of gastrointestinal epithelial neoplasia results in large differences among pathologists in the diagnosis of oesophageal, gastric, and colorectal neoplastic lesions.

AIM

To develop common worldwide terminology for gastrointestinal epithelial neoplasia.

METHODS

Thirty one pathologists from 12 countries reviewed 35 gastric, 20 colorectal, and 21 oesophageal biopsy and resection specimens. The extent of diagnostic agreement between those with Western and Japanese viewpoints was assessed by kappa statistics. The pathologists met in Vienna to discuss the results and to develop a new consensus terminology.

RESULTS

The large differences between the conventional Western and Japanese diagnoses were confirmed (percentage of specimens for which there was agreement and kappa values: 37% and 0.16 for gastric; 45% and 0.27 for colorectal; and 14% and 0.01 for oesophageal lesions). There was much better agreement among pathologists (71% and 0.55 for gastric; 65% and 0.47 for colorectal; and 62% and 0.31 for oesophageal lesions) when the original assessments of the specimens were regrouped into the categories of the proposed Vienna classification of gastrointestinal epithelial neoplasia: (1) negative for neoplasia/dysplasia, (2) indefinite for neoplasia/dysplasia, (3) non-invasive low grade neoplasia (low grade adenoma/dysplasia), (4) non-invasive high grade neoplasia (high grade adenoma/dysplasia, non-invasive carcinoma and suspicion of invasive carcinoma), and (5) invasive neoplasia (intramucosal carcinoma, submucosal carcinoma or beyond).

CONCLUSION

The differences between Western and Japanese pathologists in the diagnostic classification of gastrointestinal epithelial neoplastic lesions can be resolved largely by adopting the proposed terminology, which is based on cytological and architectural severity and invasion status.

Methylenetetrahydrofolate reductase polymorphisms, folate, and cancer risk: a paradigm of gene-nutrient interactions in carcinogenesis

Recent epidemiologic studies suggest that common polymorphisms of methylenetetrahydrofolate reductase (MTHFR) with allele frequencies up to 35% in the general North American population may modulate cancer risk. In some cancers, folate and other nutrients involved in the MTHFR metabolic pathway appear to interact with MTHFR polymorphisms to further modify cancer risk. In carcinogenesis, MTHFR polymorphisms thus provide a paradigm of gene-nutrient interactions, an emerging and important topic in the field of nutrition and cancer. Furthermore, MTHFR polymorphisms and MTHFR-nutrient interactions provide an opportunity to identify an ideal target group of individuals, at high risk of developing cancer, for rational, effective, and safe chemoprevention using these nutrients.

Effects of dietary folate on DNA strand breaks within mutation-prone exons of the p53 gene in rat colon

BACKGROUND & AIMS

Diminished folate status has been observed to increase colorectal cancer risk. Folate plays an important role in DNA synthesis and repair. This study investigated the effects of dietary folate on DNA strand breaks in the p53 and Apc genes, and how these changes are related to steady-state levels of the corresponding transcripts.

METHODS

Three groups of rats were fed diets containing 0, 2 (basal requirement), or 8 mg folate/kg for 5 weeks. At each weekly time point, plasma and colonic mucosal folate concentrations were determined. Site-specific DNA strand breaks were assessed by semiquantitative PCR. Steady-state levels of messenger RNA were measured by semiquantitative RT-PCR.

RESULTS

Dietary folate deficiency produced progressive DNA strand breaks within exons 5-8 of the p53 gene in rat colon (P<0.02). Accumulation of strand breaks was not observed in other exons of the p53 gene, in the Apc and beta-actin genes, or at the genomic level. Folate supplementation at 4 times the basal requirement significantly increased p53 integrity compared with the basal and deficient diets (P<0.05). p53 integrity in exons 5-8 was significantly correlated with folate status (P<0.03). Dietary folate deprivation progressively decreased, whereas supplementation increased, steady-state levels of p53 transcript over 5 weeks (P<0.05). No such changes were observed for the Apc gene. Steady-state levels of p53 transcript were significantly correlated with folate status and p53 integrity in exons 5-8 (P<0.002).

CONCLUSIONS

These data provide a plausible mechanism by which folate deficiency promotes, and folate supplementation suppresses, colorectal carcinogenesis.

A case of Cushing's syndrome in ACTH-secreting mediastinal paraganglioma

Paragangliomas are unusual neuroendocrine cell tumors arising from paraganglia, of which ACTH-secreting cases in the mediastinum are extremely rare. A 51-year-old woman was admitted for generalized edema and weakness which began 5 months ago. Chest X-ray and CT scan revealed a tumor mass in the anterior mediastinum. The plasma cortisol and ACTH levels were very high. Other sources secreting ACTH, except mediastinal mass, were not found. Surgical excision of mediastinal mass and left supraclavicular lymph node was performed. The postoperative microscopic finding and immunohistochemical staining revealed organoid tumor cell nests (zellballen) and S-100 protein positive sustentacular cells which are characteristics of paraganglioma. This was thus a case of Cushing's syndrome resulting from ectopic ACTH production in anterior mediastinal paraganglioma.

Chemopreventive effects of dietary folate on intestinal polyps in Apc+/-Msh2-/- mice

Epidemiological and animal studies (reviewed in Y. I. Kim, J. Nutr. Biochemistry, 10: 66-88, 1999; J. B. Mason and T. Levesque, Oncology, 10: 1727-1743, 1996) suggest that dietary folate intake is inversely related to the risk of colorectal cancer. However, the optimal timing of folate intervention and mechanisms by which folate modulates colorectal carcinogenesis have not been clearly established. A recently developed murine model of intestinal tumorigenesis, which carries a heterozygous mutation in the Apc gene and a null mutation in the Msh2 gene (Apc+/-Msh2-/-), was used to determine the effect of dietary folate on intestinal tumorigenesis. Apc+/- Msh2-/- mice were randomized to receive either 0 or 8 mg of folate/kg diet starting at either 3 or 6 weeks of age. The 3- and 6-week diet starts represent intervention before and after the establishment of neoplastic foci, respectively. At 11 weeks of age, mice were killed, and the small intestines and colons were analyzed for adenomas and aberrant crypt foci (ACF). Serum folate concentrations were determined by a standard microbiological assay. Genomic DNA methylation was assessed by in vitro [3H]methyl incorporation into hepatic DNA and by a methyl-sensitive restriction digestion method. Microsatellite instability was determined in matched normal and polyp DNA from the small intestine and colon at 5 loci. Serum folate concentrations accurately reflected dietary folate levels (P < 0.005). Folate supplementation, started before the establishment of neoplastic foci, significantly decreased the number of small intestinal adenomas (by 2.7-fold; P = 0.004) and colonic ACF (by 2.8-fold; P = 0.028) and colonic adenomas (by 2.8-fold; P = 0.1) compared with a moderate degree of folate deficiency. In contrast, a moderately folate-deficient diet, started after the establishment of neoplastic foci, significantly reduced the number of small intestinal adenomas (by 4.2-fold; P = 0.001) but had no effect on colonic ACF and adenomas compared with folate supplementation. Genomic DNA methylation and microsatellite instability do not seem to play a major role in folate-modulated intestinal and colonic tumorigenesis in this model. In conclusion, in this murine model, dietary folate supplementation significantly protects against small intestinal and colorectal tumorigenesis if it is provided before the establishment of neoplastic foci However, if it is provided after the establishment of neoplastic foci, dietary folate seems to have an opposite effect. These data suggest that the timing of folate intervention is critical in providing an effective and safe chemopreventive effect on intestinal tumorigenesis. Notwithstanding the limitations associated with this model, our data suggest that the optimal timing of folate intervention must be established before folate supplementation can be used as a safe chemopreventive agent against colorectal cancer.

Microsatellite instability and Epstein-Barr virus infection in gastric remnant cancers

Clinicopathological analysis, microsatellite analysis, detection of Epstein-Barr virus (EBV), and immunohistochemistry on p53 protein were performed in 26 cases of gastric remnant cancer (GRC). They were divided into two groups; Group A (n = 14) who had undergone a primary gastrectomy for benign gastric disease, and Group B (n = 12) who had undergone the same operation for gastric cancer. EBV infection was present in 29% of Group A, 8% of Group B and 6% of the conventional gastric carcinoma (CGC) (Group A vs CGC, P = 0.01). Microsatellite instability (MSI) was found in 7% of Group A, 25% of Group B, and 9% of the CGC (Group B vs CGC; P = 0.08). p53 Overexpression was observed in 46% of the GRC and 33% of the CGC. p53 Overexpression was observed in 90% of the intestinal type of GRC, but in only 20% of the diffuse type of GRC (P = 0.002). The cancer stage was a significant factor in the univariate analysis of survival (P = 0.04). In conclusion, GRC is different from CGC in terms of MSI or EBV association. The pathogenetic differences between the two groups require further investigation. EBV infection may have been involved in the carcinogenesis of Group A. MSI may be an important factor in the carcinogenesis of metachronous multiple gastric cancer (Group B).

Allelotype analysis of intrahepatic cholangiocarcinoma

To identify the chromosomal loci of allelic loss in intrahepatic cholangiocarcinoma (ICC), we performed an allelotype study of 36 ICCs using 55 genome-wide microsatellite markers. Loss of heterozygosity was found most frequently on 8p (65.6%), 17p (64.7%), and 9p (64.5%), followed by 18q (54.2%), 1p (48.5%), 3p (44.8%), 9q (42.1%), 14q (41.7%), 6q (41.7%), and 1q (40.6%). The fractional allelic loss (FAL) values ranged from 0 to 0.731 (mean, 0.322). Analysis of the relationship between FAL values and clinicopathologic parameters disclosed significantly higher FAL values in moderately to poorly differentiated ICCs than in well-differentiated ones (P < .05). In summary, this study defined for the first time the overall number of chromosomes having allelic loss and the chromosomal arms and/or regions potentially involved in the development of ICC.

Choledochal cyst: comparison of MR and conventional cholangiography

AIMS

To assess the diagnostic value of magnetic resonance (MR) cholangiography versus conventional cholangiography in patients with choledochal cyst and to determine whether MR cholangiography can be considered an alternative to conventional cholangiography.

MATERIALS AND METHODS

Thirteen patients with choledochal cyst were examined by MR cholangiography and conventional cholangiograms. Magnetic resonance cholangiography employed T2-weighted axial and coronal fast spin-echo, single and multislab single-shot fast spin-echo sequences, including source images with maximum intensity projections. The diagnostic value of MR cholangiography and conventional cholangiograms was assessed and compared using the criteria of depiction of morphology, anomalous pancreaticobiliary duct union and demonstration of complications such as stones. A four-point diagnostic scale was applied to the delineation of the ductal anatomy with the Wilcoxon signed-ranks test and McNemar's test used for statistical analysis.

RESULTS

The depiction of the choledochal cyst was significantly better with MR cholangiography than with conventional cholangiography (P = 0.03). The detection rate of an anomalous pancreaticobiliary duct union was not significantly different with either method (P = 0.641), nor was the detection rate of bile duct stones (P = 0.375).

CONCLUSION

Magnetic resonance cholangiography provides data equivalent to or superior to those from conventional cholangiography in evaluating choledochal cyst. Magnetic resonance cholangiography is recommended as a non-invasive examination of choice for the evaluation of choledochal cyst.

Role of follicular dendritic cells in the apoptosis of germinal center B cells

Follicular dendritic cells (FDCs) provide the most obvious source of antigens, which are essential for the differentiation of GC B cells. It has been reported that most proliferating B cells in germinal centers undergo apoptosis. Quantitative histology shows macrophages with apoptotic debris throughout the germinal center, the highest frequency of these cells being found in the dense FDC network. Based on these findings, we hypothesized that FDC may be involved in an apoptotic pathway of the germinal center B cells. To prove this hypothesis, we performed double immunohistochemical analysis using anti-FDC mAb and peanut agglutinin (PNA), with their respective TUNEL kits. Collated data showed that a great proportion of the apoptotic cells, most of which were positive for PNA, were in close contact with FDC, which indicated an interaction between FDC and B cells in the apoptotic pathway. Further studies using double immunohistochemical staining and FACS analyses demonstrated the expression of Fas-ligand (FasL) in a subset of the FDC. These results suggest that FDC may play a role in the apoptosis of germinal center B cells via Fas-FasL interaction.

Amelioration of tumor necrosis factor release by cyclosporine in warm ischemia/reperfusion injury of the rat liver: with special reference to hepatic ultrastructure

Mechanisms by which an immunosuppressant (cyclosporine, CsA) ameliorates warm ischemic injury of the liver were studied. Female Sprague-Dawley rats were subjected to 60-min normothermic liver ischemia. Animals were assigned to one of two groups: group I, controls with vehicle treatment; group II, treatment with CsA (10 mg/kg). CsA was given orally for 4 consecutive days prior to the induction of hepatic ischemia. In addition to a survival study, plasma levels of endotoxin, serum activity of tumor necrosis factor-alpha (TNF), and serum levels of aminotransferases were measured in blood samples collected from the suprahepatic vena cava, and hepatic ultrastructural alterations were examined under an electron microscope. The 7-day survival rate was significantly higher in the CsA-treated animals. In the control group, serum TNF levels were elevated following reperfusion and peaked at 3 h. When the values at 3 h post reflow were compared, the animals given CsA had significantly lower levels of TNF (170.0 +/- 30.5 pg/ml for group I, 67.6 +/- 13.7 for group II, mean +/- SEM; P < 0.05). The sinusoidal lining cells and hepatocytes were drastically destroyed at 6 h post reflow in the control group, although the degree of injury at 1-3 h was less severe. On the other hand, the endothelium and parenchymal liver cells in the CsA-treated group were well preserved at 6 h in comparison with those in the control group. Our data suggest that modulation of TNF production is one of the mechanisms through which CsA prevents the exacerbation of ischemia/reperfusion injury of the liver.