Insulinlike growth factor II expression and oval cell proliferation associated with hepatocarcinogenesis in woodchuck hepatitis virus carriers.

Insulinlike growth factor II (IGF-II) is a highly mitogenic fetal growth factor suspected of regulating the growth of a wide spectrum of tissues via an autocrine or paracrine mode of action or both. High steady-state levels of IGF-II RNA were detected in 45% of hepatocellular carcinomas (HCCs) arising from woodchuck livers with persistent woodchuck hepatitis virus (WHV) infection. Analysis of WHV RNA in the same HCCs revealed that HCCs with high levels of IGF-II RNA contained low or undetectable levels of WHV RNA and HCCs with low levels of IGF-II RNA contained high levels of WHV RNA. Integrated WHV DNA was present in HCCs from both groups, but viral DNA replicating forms were present, predominantly in HCCs with low levels of IGF-II. Several IGF-II RNAs, the most prominent of which were poly(A) species of approximately 3.75 and 1.1 to 1.3 kilobases, were detected only in precancerous nodules and HCCs. Levels of IGF-II were elevated two- to three-fold in the serum of woodchucks with chronic active hepatitis preceding the occurrence of HCC. Proliferation of a population of oval cells, which arise from portal tract regions in the liver, preceded the development of HCC and was a prominent feature of livers from which tumors with high levels of IGF-II occurred. The HCCs tended to have distinct histological features according to their growth factor status. Tumors with low levels of IGF-II were generally highly differentiated acinar-trabecular HCCs, whereas tumors with high levels of IGF-II were more anaplastic, with regions of fibrosis and fatty accumulation. A model to relate the pathology of WHV infection to oval cell proliferation and IGF-II expression in the development of these heterogeneous HCCs is presented.     

Hexokinase and glucose-6-phosphatase activity in woodchuck model of hepatitis virus-induced hepatocellular carcinoma

2-Deoxy-2-[(18)F]fluoro-D-glucose ([(18)F] FDG) is used for PET imaging of woodchuck (Marmota monax) model of hepatocellular carcinoma (HCC). The usefulness of FDG on this animal model needs to be validated according to the hypothesized mechanisms. In this study, two key enzymes involved in glucose or [(18)F] FDG metabolism, hexokinase (HK) and glucose-6-phophatase (G6Pase), were examined for their enzymatic activities in the woodchuck models of HCC, which has not been studied before. After dynamic PET scans, woodchuck liver tissue samples were harvested and the homogenate was centrifuged. The supernatant was used for HK activity assay and the microsomal pellet was used for G6Pase assay. HK and G6Pase activities were measured by means of colorimetric reactions via kinetic and end-point assays, respectively. Total protein content was measured by the Bradford method and used to normalize all enzyme activities. HK and G6Pase activities in woodchuck HCC will be used to correlate with in vivo PET imaging data. The woodchuck model of HCC had significantly increased levels of HK in the livers compared to the age-matching healthy woodchuck (7.96 +/- 1.27 vs. 2.74 +/- 0.66 mU/mg protein, P < 0.01) and significantly decreased levels of G6Pase compared to healthy woodchuck (40.35 +/- 19.28 vs. 237.01 +/- 17.32 mU/mg protein, P < 0.01), reflecting an increase in glycolysis. In addition, significant differences were found in HK and G6Pase activities between HCC liver region (HK: 7.96 +/- 1.27 mU/mg protein; G6Pase: 40.35 +/- 19.28 mU/mg protein) and surrounding normal liver region (HK: 2.98 +/- 0.92 mU/mg protein; G6Pase: 140.87 +/- 30.62 mU/mg protein) in the same woodchuck model of HCC (P < 0.01). Our study demonstrated an increased HK activity and a decreased G6Pase activity in liver of the woodchuck models of HCC as compared to normal woodchuck liver.     

Fine needle aspiration biopsy of hepatocellular carcinoma and hepatocellular nodular lesions: role,controversies and approach to diagnosis

A. Wee
Fine needle aspiration biopsy of hepatocellular carcinoma and hepatocellular nodular lesions: role, controversies and appr oach to diagnosis The role of fine needle aspiration (FNA) biopsy of the liver has evolved. Advances in imaging modalities have obviated the need for tissue confirmation in clinically classic hepatocellular carcinoma (HCC). The risks of needle tract seeding and haematogenous dissemination have been actively debated. Nowadays, cytopathologists are confronted by smaller and smaller nodules, detected due to increased surveillance of high‐risk cirrhotic patients. Tissue characterization of small well‐differentiated hepatocellular nodular lesions (size less than and equal to 2 cm) is extremely challenging and has therapeutic implications. Major issues in the cytodiagnosis of HCC include: (i) distinguishing benign hepatocellular nodular lesions, namely, large regenerative nodules, dysplastic nodules, focal nodular hyperplasia and hepatocellular adenoma from reactive hepatocytes; (ii) distinguishing well‐differentiated HCC from benign hepatocellular nodular lesions; (iii) distinguishing poorly differentiated HCC from intrahepatic cholangiocarcinoma and metastatic carcinomas; (iv) determining the histogenesis of a malignant tumour; and (v) determining the site of origin of a malignant tumour. An overview of the biological evolution and histopathological aspects of dysplastic nodules, small HCCs and ‘nodule‐in‐nodule’ lesions is presented in tandem with clinically relevant nomenclature. An algorithmic approach to FNA diagnosis of HCC and hepatocellular nodular lesions is outlined. Optimal results depend on (i) a dedicated radiologist‐cytopathologist team; (ii) an on‐site cytology service, (iii) a combined cytohistological approach, (iv) immunohistochemistry, and (v) clinicopathological correlation. As we move towards personalized medicine, it is envisaged that hepatic FNA is likely to become a point of care in the management protocol as it takes on the additional role of procurement of tumour and peritumoural tissues for genomic and proteomic profiling to enable targeted molecular therapy.     

Comprehensive Comparison of Multiple-Detector Computed Tomography and Dynamic Magnetic Resonance Imaging in the Diagnosis of Hepatocellular Carcinoma with Varying Degrees of Fibrosis

Methods841 patients with liver tumor who had liver CT or dynamic MRI examinations followed by surgical resection were included in the study. We defined typical HCC imaging characteristics as early enhancement in the artery phase and early washout in the venous phase. The tumor size was recorded based on pathological examination after surgery. The pathologic fibrosis score was verified by the METAVIR scoring classification.ResultsAmong the 841 patients, 756 underwent liver CT and 204 underwent dynamic liver MRI before surgery. The etiologies of chronic liver disease included hepatitis B virus, hepatitis C virus, hepatitis B and C virus, and non-hepatitis B or C virus. The sensitivity and accuracy of liver CT or MRI for HCC diagnosis was approximately 80%~90%. Liver CT had a diagnostic accuracy for HCC similar to that of dynamic MRI, and liver fibrosis stage did not influence their diagnostic efficacies.ConclusionsThe application of 4-phase dynamic CT and MRI exhibit similar diagnostic accuracy for hepatocellular carcinoma, in tumors of sizes 1 to 2 cm and >2 cm. Liver fibrosis status did not affect the diagnostic accuracy of liver CT or MRI for HCC. The AASLD and EASL restrictions of dynamic imaging studies for HCC diagnosis to cirrhotic patients alone are unnecessary.     

A colorimetric assay method to measure acetyl-CoA synthetase activity: application to woodchuck model of hepatitis virus-induced hepatocellular carcinoma

A new spectrophotometric method for quantitation of acetyl-CoA synthetase (ACAS) activity is developed. It has been applied for ACAS assay in the liver tissues of a woodchuck model of hepatitis virus-induced hepatocellular carcinoma (HCC). The assay is based on the established pyrophosphate (PPi) detection system. ACAS activity is indexed by the amount of PPi, the product of ACAS reaction system of activated form of acetate (acetyl-CoA) with ACAS catalysis. PPi is determined quantitatively as the amount of chromophore formed with molybdate reagent, 1-amino-2-naphthol-4-sulfonic acid in bisulfite and 2-mercaptoethanol. PPi reacts with molybdate reagent to produce phosphomolybdate and PPi-molybdate complexes. 2-mercaptoethanol is responsible for color formation which has the peak absorbance at 580 nm. This method was sensitive from 1 to 20 nmol of PPi in a 380-mul sample (1-cm cuvette). A ten-fold excess of Pi did not interfere with the determination of PPi. To study the major metabolic pathways of imaging tracer [1-(11)C]-acetate in tumors for detection of HCC by Positron Emission Tomography (PET), the activity of one of the key enzymes involved in acetate or [1-(11)C]-acetate metabolism, ACAS was assayed by this newly developed assay in the tissue samples of woodchuck HCCs. A significant increase of ACAS activity was observed in the liver tissues of woodchuck HCCs as compared with neighboring regions surrounding the tumors (P<0.05). The respective ACAS activities in the subcellular locations were also significantly higher in HCCs than in the surrounding tissues (P<0.05) (total soluble fraction: 876.61+/-34.64 vs. 361.62+/-49.97 mU/g tissue; cytoplasmic fraction: 1122.02+/-112.39 vs. 732.32+/-84.44 mU/g tissue; organelle content: 815.79+/-100.77 vs. 547.91+/-97.05 mU/ g tissue; sedimentable fragment: 251.92+/-51.56 vs. 90.94+/-18.98 mU/ g tissue). The finding suggests an increase in ACAS activity in the liver cancer of woodchuck models of HCC as compared to that in the normal woodchuck liver. The developed assay is rapid, simple and accurate and is suitable for the investigation of ACAS activity under physiologic and pathophysiologic conditions.     

A new hepadnavirus endemic in arctic ground squirrels in Alaska.

We present evidence for a novel member of the hepadnavirus family that is endemic in wild arctic ground squirrels (Spermophylus parryi kennicotti) in Alaska. This virus, designated arctic squirrel hepatitis virus (ASHV), was initially detected in the livers of animals bearing large hepatic nodules by nucleic acid hybridization with hepadnavirus probes and in plasma by cross-reactivity with antibodies to hepadnavirus surface and core antigens. The complete nucleotide sequence of the 3,302-bp-long ASHV genome was determined and compared with those of ground squirrel hepatitis virus (GSHV) and woodchuck hepatitis virus (WHV); all sequences were organized into four open reading frames, designated pre-C/C, pre-S/S, pol, and X. Despite roughly equivalent variability among the three rodent hepadnaviruses (around 16% base and 19% amino acid exchanges), ASHV appeared to be more closely related to GSHV than to WHV in phylogenetic analysis. Accordingly, preliminary studies of the pathology of ASHV infection suggested that ASHV may be a less efficient oncogenic agent than WHV. About one-third of aged animals maintained in captivity, including virus-infected as well as uninfected squirrels, developed large liver nodules, consisting of hepatocellular adenomas or carcinomas or nonmalignant lesions characterized by drastic microvesicular steatosis. ASHV-infected arctic ground squirrels may serve as a new model with which to analyze the contribution of hepadnavirus- and host-specific determinants to liver pathology and tumorigenesis.     

Molecular characterization of woodchuck interleukin 15 (wIL-15) and detection of its expression in liver samples of woodchucks infected with woodchuck hepatitis virus (WHV)

Interleukin 15 (IL-15) is a member of the four-helix bundle cytokine family and has T cell growth factor activity. IL-15 plays a unique role in both innate and adaptive immune cell homeostasis, particularly for the development of NK cells and CD8+memory cells. It may be useful for stimulation of specific immune responses in chronic viral infection such as hepatitis B virus infection. The woodchuck model is an informative animal model for studies on hepadnavirus infection and therapeutic interventions. Here, the complete coding sequence of woodchuck IL-15 (wIL-15) was cloned and sequenced. wIL-15 shows a high homology (>70%) to its counterparts of other mammalian species. His-tagged recombinant wIL-15 protein was expressed and purified and showed the ability to promote the proliferation of activated mouse splenocytes and woodchuck peripheral blood lymphocytes. Further, examination of mRNA amounts in liver samples of woodchucks by semi-quantitative RT-PCR showed a slightly increased expression of wIL-15 in woodchuck livers during chronic woodchuck hepatitis virus infection. This available information will provide a basis for further studies on the function of IL-15 in the context of acute and chronic hepadnavirus infection and its potential therapeutic use for chronic hepatitis B virus infection in the woodchuck model.     

Thyroid Nodules Detected by Contrast-Enhanced Magnetic Resonance Angiography: Prevalence and Clinical Significance

Background and Purpose

Incidental thyroid lesions are frequently found on contrast-enhanced magnetic resonance (CE-MR) angiography. The purpose of this study is to determine the prevalence of thyroid incidentalomas detected by CE-MR angiography and to evaluate their clinical significance by correlation with ultrasound (US) and cytopathological results.

Materials and Methods

We retrospectively reviewed 3,299 consecutive CE-MR angiography examinations performed at our institution between January 2010 and March 2013. Two radiologists evaluated the CE-MR angiography imaging in consensus regarding the presence, location, and vascularity of thyroid incidentaloma. We correlated these findings with follow-up US and cytopathologic results.

Results

The prevalence of thyroid incidentalomas detected by CE-MR angiography was 4.6% (152/3,299 patients). CE-MR angiography showed hypervascularity in 86.8% (145/167), isovascularity in 8.4% (14/167), and hypovascularity in 4.8% (8/167) of thyroid nodules compared to vascularity of thyroid parenchyma. Among the patients with thyroid incidentaloma, 34 patients (22.4%) were followed by US examination, and all 36 nodules on CE-MR angiography were detected on follow-up US. Of these nodules, 9 (25%) nodules were classified as probably benign, 26 (72.2%) as indeterminate, and 1 (2.8%) as suspicious malignant nodule. Among the 16 nodules with available cytopathologic results, 12 nodules were benign, 2 nodules were follicular neoplasm, and 2 nodules showed non-diagnostic results.

Conclusion

Incidental thyroid nodules were found in 4.6% of CE-MR angiography examinations. Because the high incidence of indeterminate US feature among thyroid incidentaloma, when a thyroid incidentaloma is detected on CE-MR angiography, further evaluation with US should be performed.     

Imaging diagnosis of schistosomiasis japonica--the use in Japan and application for field study in the present endemic area

For detecting lesions-related schistosomiasis japonica, X-rays, scintillation scanning, ultrasonography (US), computed tomography (CT), magnetic resonance (MR) and endoscopic examinations with biopsies have been used in Japan. Liver fibrosis and calcified changes are detected by US and CT. Most of the lesions that are detected by endoscopic examinations are due to deposited ova of Schistosoma japonicum. Portal hypertension is detected by US, CT and gastroscopic examination. Because schistosome infection decreased rapidly in Japan, most of the studies on imaging diagnosis were performed on chronic lesions or sequelae of schistosomiasis. Most of the techniques were used on admitted patients in well-equipped hospitals. US was introduced in the 1970s as a safe, rapid, non-invasive and inexpensive technique and has been used for diagnosis in hospitals and screening in the fields. As a typical US image of the liver, septal formation by high echogenic bands like mosaic was described, and this network pattern was reported in the other endemic countries; China and Philippines. As an appropriate technique, US has been broadly used in developing countries. Not only for diagnosis in a hospital, but also for monitoring changes of morbidity, US is used in the community level. Network pattern related to the severity of S. japonicum infection, has not been described in S. mansoni or S. haematobium infection. Appearance of network pattern depends on pathological changes such as periportal fibrosis, postnecrotic fibrosis and calcified ova. For advanced studies on morbidity of schistosomiasis japonica, further research on pathological basis of network pattern and standardization of US diagnosis are necessary.     

超声随访在肝硬化结节恶变筛查及诊断中的价值研究

目的:研究超声随访在肝硬化结节恶变筛查及诊断中的价值。方法:选取我院收治的乙肝后肝硬化患者83例,均采取超声检查,观察超声随访在肝硬化结节恶变筛查及诊断中的应用价值。结果:本组83例随访发现,出现肝硬化伴增生性结节患者演变小肝癌21例。增生性结节患者的增生性结节直径与小肝癌患者肿块直径比较,差异无统计学意义(P0.05)。增生性结节患者的回声情况与小肝癌患者比较,差异有统计学意义(P0.05)。超声随访发现,结节由112个增加至126个,结节数量增加。肝硬化结节14例,在超声引导下行肝穿刺活检,成功13例,失败1例,病理诊断肝硬化结节患者9例,肝癌患者3例,与超声的检查结果相同。结论:超声随访在肝硬化结节恶变的筛查诊断中具有较高的临床价值,可在早期提供较为准确的检查结果,帮助医师做出诊断,及早治疗以改善预后。     

Molecular characterization of woodchuck interleukin 15 (wIL-15) and detection of its expression in liver samples of woodchucks infected with woodchuck hepatitis virus (WHV)

Interleukin 15 (IL-15) is a member of the four-helix bundle cytokine family and has T cell growth factor activity. IL-15 plays a unique role in both innate and adaptive immune cell homeostasis, particularly for the development of NK cells and CD8 + memory cells. It may be useful for stimulation of specific immune responses in chronic viral infection such as hepatitis B virus infection.The woodchuck model is an informative animal model for studies on hepadnavirus infection and therapeutic interventions. Here, the complete coding sequence of woodchuck IL-15 (wIL-15) was cloned and sequenced. wIL-15 shows a high homology (>70%) to its counterparts of other mammalian species. His-tagged recombinant wIL-15 protein was expressed and purified and showed the ability to promote the proliferation of activated mouse splenocytes and woodchuck peripheral blood lymphocytes. Further, examination of mRNA amounts in liver samples of woodchucks by semi-quantitative RT-PCR showed a slightly increased expression of wIL-15 in woodchuck livers during chronic woodchuck hepatitis virus infection. This available information will provide a basis for further studies on the function of IL-15 in the context of acute and chronic hepadnavirus infection and its potential therapeutic use for chronic hepatitis B virus infection in the woodchuck model.     

Serum heat shock protein 27 levels in patients with hepatocellular carcinoma

Levels of serum heat shock protein 27 (sHsp27) have been studied in numerous cancer types, but their potential relevance in patients with hepatocellular carcinoma (HCC) is undetermined. Our aim was to compare sHsp27 levels in patients with HCC and HCC-free controls. Specifically, we recruited 71 patients with HCC (80 % with early tumour), 80 patients with chronic liver disease (59 with liver cirrhosis and 21 with chronic active hepatitis) and 42 healthy subjects. sHsp27 was measured by immunoenzymatic assay. Results showed that sHsp27 levels were significantly (p < 0.001) higher in patients with HCC than in the other groups, particularly in those with hepatitis C virus (HCV)-related disease. In HCC patients, sHsp27 levels were not associated with prognostic risk factors, such as size/multiplicity of nodules and stage. In logistic regression analysis, performed in patients with liver disease, log-sHsp27 was associated with a significant age-adjusted 2.5-fold increased odds ratio of HCC and with a significant 4.4-fold higher odds ratio of HCC in the subgroup with HCV-related liver disease. In receiver operating characteristic curve analysis, sensitivity and specificity of the best sHsp27 cut-off value (456.5 pg/ml) for differentiating patients with HCC from those with HCC-free chronic liver disease were 70 and 73 %, respectively. In conclusion, sHsp27 levels are enhanced in patients with HCC and may represent a candidate biomarker of HCC.     

Pattern analysis of serum alpha-fetoprotein in the early diagnosis of hepatocellular carcinoma in liver cirrhosis

In a surveillance program for hepatocellular carcinoma (HCC), serum alpha-fetoprotein (AFP) was determined every 4 months in 164 patients with liver cirrhosis. Ultrasonography (US) was performed yearly or as dictated by abnormal AFP levels. During a follow-up of 32.5 +/- 20.8 months HCC was identified by US in 16 patients. In 9 of them the AFP levels rose steadily over 4 months, increasing 7, 8 and 12 months in 3 cases before the lesion became detectable by US. In 4 patients tumors developed despite persistently normal AFP levels. Nine more patients showed abnormal fluctuations of AFP but HCC was not detected. AFP sensitivity was higher at a low cut-off point (40 ng/ml) while specificity of the test appeared higher at the 200 ng/ml cut-off point. An AFP value rising steeply over a few months appeared more reliable than a fixed preset threshold in indicating carcinomatous transformation. Screening for AFP can be expected to uncover about 3/4 of HCC developing in cirrhotics with few false-positive reactions. The test may have a unique role in identifying a subset of liver tumors whose early expression is AFP production.     

Quick and reversible inhibition of soybean root nodule growth by nitrate involves a decrease in sucrose supply to nodules

The upper part of a nodulated soybean root hydroponically cultured in a glass bottle was monitored using a computer microscope under controlled environmental conditions, and the diameter of individual nodules was measured from 10-24 d after planting. The diameter of a root nodule attached to the primary root increased from 1 mm to 6 mm for 2 weeks under nitrogen-free conditions. The increase in diameter of the nodules was almost completely stopped after 1 d of supplying 5 mM nitrate, and was due to the cessation of nodule cell expansion. However, nodule growth quickly returned to the normal growth rate following withdrawal of nitrate from the solution. The reversible depression of nodule growth by nitrate was similar to the restriction of photoassimilate supply by continuous dark treatment for 2 d followed by normal light/dark conditions. In addition, the inhibitory effect of nitrate was partially alleviated by the addition of 3% (w/v) sucrose to the medium. Plant leaves were exposed to (11)C or (14)C-labelled carbon dioxide to investigate the effects of 5 mM nitrate on the translocation and distribution of photosynthates to nodules and roots. Supplying 5 mM nitrate stimulated the translocation rate and the distribution of labelled C in nitrate-fed parts of the roots. However, the (14)C partitioning to nodules decreased from 9% to 4% of total (14)C under conditions of 5 mM nitrate supply. These results indicate that the decrease in photoassimilate supply to nodules may be involved in the quick and reversible nitrate inhibition of soybean nodule growth.     

128层螺旋CT 低剂量扫描检查孤立性肺内结节性病灶的研究

目的:探讨多排螺旋CT(128排)低剂量扫描参数下检查孤立性肺内结节的可行性研究。方法:随机连续搜集我院低剂量(30m A)CT肺体检者,发现肺内结节病灶患者13例,对其进一步以常规剂量(350m A)CT精细扫描,比较低剂量扫描及常规剂量扫描肺结节大小差异。结果:两种剂量扫描策略均检查出46枚结节。常规剂量与低剂量测得各部位结节体积分别为:肺尖部:(431.3±92.8)mm~3,(658.4±94.4)mm~3,肺中部:(3025.8±526.7)mm~3,(2989.4±520.4)mm~3,肺底部:(1241.5±438.9)mm~3,(1266.0±447.6)mm~3,肺尖部肺结节大小差异明显,肺中部及肺底部肺结节大小均无显著性差异(P0.05)。常规剂量与低剂量测得结节体积(除外肺尖部位结节5枚)分别为,组1:(39.8±14.6)mm~3,(40.7±15.5)mm~3;组2:(202±106.3)mm~3,(204.1±103.6)mm~3;组3:(4179.7±4410.4)mm~3,(4190.5±4487.2)mm~3。三组组内测量结果均无显著性差异(P0.05)。常规剂量与低剂量测得非实性结节密度[(-68.3±24.2)HU,(-64.6±22.8)HU]及实性结节结节密度[(97.5±69.5)HU,(107.2±90)HU]均无统计学差异(P0.05)。结论:低剂量更加有利于肺内孤立结节患者扫描复查病灶,可以应用推广。     

Core antigen and antibody in woodchucks after infection with woodchuck hepatitis virus

The woodchuck hepatitis virus is a naturally occurring hepatitis B-like virus that infects the eastern woodchuck. Direct immunofluorescence staining for woodchuck hepatitis virus core antigen in liver biopsies demonstrated the presence of this antigen in 14 of 17 chronically infected woodchucks, and in 8 of 10 woodchucks undergoing acute infections. Fluorescent localization of woodchuck hepatitis virus core antigen was typically cytoplasmic, and this was confirmed further by electron microscopy. Experimental infection with woodchuck hepatitis virus was achieved in four of four woodchucks inoculated with serum from chronic carrier woodchucks. All infected animals developed a self-limited disease characterized by seroconversion to antibodies against the major viral antigens (core and surface antigens); naturally acquired acute infection demonstrated a similar course. A chimpanzee seronegative for all markers of hepatitis B virus developed a subclinical infection after inoculation with woodchuck hepatitis virus.     

Three-dimensional image analysis of the hepatic restructuring process in chronic active hepatitis

OBJECTIVE: To elucidate the process of hepatic restructuring in the course of chronic hepatitis from a morphologic viewpoint. STUDY DESIGN: The three-dimensional (3-D) liver structure was investigated by computer-aided reconstruction in five cases (one autopsy and four surgical cases) of chronic active hepatitis (type C), including early to late stages of restructuring. RESULTS: Our 3-D reconstruction revealed the following. At an early stage, portal and periportal inflammation and fibrosis widened the portal tracts, giving rise to the formation of portal-to-portal and portal-to-hepatic venous connections, although most central veins were still located at an almost normal site in the hepatic lobules. In a middle stage, bridging fibrosis developed to create a network of interstitium where the central veins were rather decreased in number, with regenerative nodules multiplying in the parenchyma. At the late stage, the lobular structure was destroyed, and the parenchyma consisted uniformly of regenerative nodules, with remaining but rearranged lobules among them. CONCLUSION: The above changes of liver structure suggest that in cirrhogenesis from chronic hepatitis, a combination of nodular regeneration and formation of an interstitial network come to replace the normal lobular structure, hastening the development of liver cirrhosis.     

Lymphosarcoma in the laboratory woodchuck (Marmota monax)

From 1979 to 1999,28 cases of lymphosarcoma were identified in the Cornell University woodchuck colony (prevalence rate: 152/100,000/yr). The prevalence of lymphosarcoma was similar in woodchucks not infected with the woodchuck hepatitis virus (WHV) and in chronic carriers of WHV. Males (13) and females (15) alike were affected (mean +/- SD age 4.7 +/- 2.92 years; range, 0.5 to 9 years). On the basis of the major organ system involved, woodchuck lymphosarcoma was classified as multicentric (12 cases, 43%), alimentary (5 cases, 18%), cranial mediastinal (5 cases, 18%), and miscellaneous (6 cases, 21%). A cutaneous form was not observed. Morphologic criteria similar to those of the Kiel classification were used for light microscopic classification. All Kiel categories-except the immunoblastic form-were found: 17 cases (61%) were centroblastic, and 6 were lymphocytic (21%). Other categories (centrocytic and plasmacytoid) were recognized less frequently. Immunophenotyping of 27 cases revealed 15 (56%) B cell (CD3-/CD79a+ or CD3-/BLA.36+), 7 (26%) T cell (CD3+/CD79a-/BLA.36-), and 5 (18%) non-T non-B cell (CD3-CD79a-/BLA.36-) lymphosarcomas. Lymphosarcoma in woodchucks develops at a higher rate than that observed in humans or companion animals, and WHV infection has no effect on prevalence. The anatomic and Kiel classification used in domestic species also can be used in woodchucks. Commercially available alpha-CD3, alpha-CD79a, and alpha-BLA.36 antibodies were useful for immunophenotyping woodchuck lymphosarcomas.