Increased uptake of bromodeoxyuridine by hepatocytes from early stage of primary biliary cirrhosis

Peptides and Peptidomimetics for Antimicrobial Drug Design

The purpose of this paper is to introduce and highlight a few classes of traditional antimicrobial peptides with a focus on structure-activity relationship studies. After first dissecting the important physiochemical properties that influence the antimicrobial and toxic properties of antimicrobial peptides, the contributions of individual amino acids with respect to the peptides antibacterial properties are presented. A brief discussion of the mechanisms of action of different antimicrobials as well as the development of bacterial resistance towards antimicrobial peptides follows. Finally, current efforts on novel design strategies and peptidomimetics are introduced to illustrate the importance of antimicrobial peptide research in the development of future antibiotics.

Clinical features of symptomatic primary biliary cirrhosis initially complicated with esophageal varices

BACKGROUND

Esophageal varices (EV), one feature of portal hypertension, have been regarded as a late complication of liver diseases. However, accumulating evidence indicates that EV sometimes develop early during the course of primary biliary cirrhosis (PBC). The prognosis is usually poorer for patients with symptomatic PBC than for those with asymptomatic PBC. Nevertheless, the clinical features and prognosis of patients with PBC whose initial symptoms are EV have not been clarified.

METHODS

The clinical features and the prognosis of patients who initially developed EV without other symptoms (v-PBC) were retrospectively investigated in 54 patients with symptomatic PBC.

RESULTS

The leukocyte and platelet counts were lower in patients with v-PBC than in those with PBC accompanied by other symptoms (s-PBC). Liver function tests, autoantibodies, and histological stage did not differ between patients with v-PBC and those with s-PBC. Although the prognosis did not differ, the incidence of hepatocellular carcinoma was significantly higher in v-PBC than in s-PBC (P = 0.0037).

CONCLUSIONS

These data indicate that v-PBC is a hypercarcinogenic state and constitutes a new subgroup of PBC.

Hepatocyte proliferative activity in human liver cirrhosis

BACKGROUND/AIMS

The objective of this study was to validate, with an independent prospective cohort of patients, our previous data indicating that the proliferating cell nuclear antigen-labeling index (PCNA-LI) reflects the liver functional reserve in human cirrhosis and might have prognostic significance for patient survival. We also examined how this proliferative index is related to the expression of transforming growth factor beta1 (TGFbeta1) as a possible correlate of hepatocyte proliferative activity.

METHODS

The present group (n=70 patients) was similar in composition to our previous group regarding age, sex and severity of liver cirrhosis. PCNA and TGFbeta1 immunostaining were analyzed on methanol-fixed, paraffin-embedded liver biopsies.

RESULTS

Our data show that PCNA-LI declined significantly with worsening Child class and was negatively correlated with the Pugh score. Twenty-five patients died and 10 underwent liver transplantation during the observation period. Liver function, hepatic venous pressure gradient and hepatocyte PCNA-LI were significantly different in survivors and non-survivors. At a mean follow-up of 356 days, the patients with a PCNA-LI higher than 4.4% (the previously determined best cut-off value) had a significantly higher probability of survival than those with a PCNA-LI < or = 4.4% (0.87 vs 0.48, p=0.0009). TGFbeta1 expression in liver parenchyma correlated negatively with PCNA-LI, suggesting that this cytokine could be involved in the impaired regeneration observed in worsened liver cirrhosis.

CONCLUSIONS

This prospective study strengthens our previous observation that, in cirrhosis, hepatocyte proliferative activity, as evaluated by the PCNA-LI, provides information on liver functional reserve as well as on the patient's prognosis.

Liver regeneration: methods for monitoring and their applications

Liver regeneration is an essential component of the reparative process following liver injury and surgical resection. It can be assessed by different tissue-based tests such as liver weights, mitotic counts, DNA contents and synthesis rates, immunohistochemical staining of nuclear antigens, gene expressions and certain protein levels or various serum-based tests that largely consist of specific enzyme determinations or documentation of certain proliferation markers. Although the simplest tissue-based test of liver regeneration is measurement of liver weights, these determinations are influenced by the extent of deposition of various materials not directly related to regeneration, such as lipids, glycogen and blood volumes. Because mitosis constitutes a very short segment of the cell cycle, mitotic counts are infrequently observed by light microscopy. Thymidine and BrdU incorporation into DNA are the reference tools for studying DNA synthesis, but their use requires pre-injection with radioactive isotopes or nucleotides which render them impractical for human studies. Flow cytometry is an accurate and objective method of monitoring hepatic regenerative activity but requires sophisticated equipment that is not generally available in many laboratories. Immunohistochemical staining for nuclear antigens (Ki-67, proliferating cell nuclear antigen [PCNA], DNA polymerase alpha and nucleolar organizer region [NOR] proteins) are acceptable and commonly used methods of monitoring regenerative activity but are subject to inter- and intra-observer variability. Gene expression rates such as Histone-3 mRNA abundance are hampered by the relatively low rates of gene transcription and the need for recombinant DNA technology. Protein and enzyme levels in liver tissues, such as putrescine, ornithine decarboxylase and thymidine kinase, are not precise and are confounded by the nutritional status of the host. While PCNA protein levels measured by immunoblot hold promise as a simple, accurate and reproducible marker of liver regeneration, additional studies are required to determine if this is a valid marker of regenerative activity in various models of hepatic injury and in humans. Of the serum-based determinations: thymidine kinase, ornithine decarboxylase, fibronectin, alpha fetoprotein, and early pregnancy factor offer practical and non-invasive tools to monitor liver regeneration, but the sensitivity and specificity of these tests have yet to be determined. In conclusion, many tissue and serum-based methods have been employed in clinical and experimental studies to assess liver regeneration; however, a gold standard has yet to be identified. Because of the disadvantages inherent in each method, and until a new, more accurate marker is identified, clinicians and scientists should incorporate a minimum of two independent markers in studies of liver regeneration.

Bromodeoxyuridine: a diagnostic tool in biology and medicine, Part III. Proliferation in normal, injured and diseased tissue, growth factors, differentiation, DNA replication sites and in situ hybridization

This paper is a continuation of parts I (history, methods and cell kinetics) and II (clinical applications and carcinogenesis) published previously (Dolbeare, 1995 Histochem. J. 27, 339, 923). Incorporation of bromodeoxyuridine (BrdUrd) into DNA is used to measure proliferation in normal, diseased and injured tissue and to follow the effect of growth factors. Immunochemical detection of BrdUrd can be used to determine proliferative characteristics of differentiating tissues and to obtain birth dates for actual differentiation events. Studies are also described in which BrdUrd is used to follow the order of DNA replication in specific chromosomes, DNA replication sites in the nucleus and to monitor DNA repair. BrdUrd incorporation has been used as a tool for in situ hybridization experiments.

Hepatocyte proliferation in primary biliary cirrhosis as assessed by proliferating cell nuclear antigen and Ki-67 antigen labelling

Expression of the proliferating cell nuclear antigen and Ki-67 antigen by hepatocytes was investigated in liver tissue specimens of 29 patients with primary biliary cirrhosis (stage I 13, stage II 6, stage III 5 and stage IV 5 patients) prior to treatment with ursodeoxycholic acid and of five control subjects using immunocytochemical methods. Proliferating cell nuclear antigen and Ki-67 expression were reevaluated in seven patients after 3 years of treatment with ursodeoxycholic acid. Proliferating cell nuclear antigen labelling indices were significantly higher in primary biliary cirrhosis (stage I, 6.4% to 32.4%, median, 10.9%; stage II, 9.6% to 21.6%, median 11.4%; stage III, 5.2% to 12.5%, median, 7.6%; stage IV, 3.8% to 8.9%, median, 5.6%) than in controls (0% to 0.5%, median, 0.1%; p < 0.005). Ki-67 antigen labelling counts were lower than proliferating cell nuclear antigen indices but elevated in all stages of primary biliary cirrhosis (stage I, 0.5% to 3.5%, median 2.0%; stage II, 1.8% to 3.6%, median 2.6%; stage III, 1.3% to 2.5%, median 1.9%; stage IV, 0.4% to 1.7%, median 1.0%) compared with controls (0% to 0.5%, median 0.3%; p < 0.005). After ursodeoxycholic acid treatment, mean proliferating cell nuclear antigen and Ki-67 labelling indices decreased from a median of 9.0% (range, 3.8% to 32.4%) to a median of 7.8% (range, 4.5% to 17.2%; p = 0.045) for proliferating cell nuclear antigen and from a median of 2.5% (range, 0.8% to 3.6%) to a median of 2.1% (range, 0.9% to 3.1%; p = 0.031) for Ki-67 antigen. It is concluded that hepatocyte proliferation is markedly increased in primary biliary cirrhosis, particularly in the early stages of the disease, and that ursodeoxycholic acid treatment reduces proliferative activity in primary biliary cirrhosis.

Pathology of the spleen in primary biliary cirrhosis: an autopsy study

Pathologic changes of the spleen in primary biliary cirrhosis (PBC) were studied using autopsy cases. By analysis of the data complied in the Annual Registry of Autopsies of Japan (1977-92), it was found that the splenic weight of 184 cases of PBC (450 +/- 224 g) was significantly heavier than that of 41 control autopsy cases of non-biliary liver cirrhosis from the School of Medicine, Kanazawa University (341 +/- 189 g), and also of 210 control cases filed in the Annual Registry of Autopsies of Japan (1982; 334 +/- 174 g). Among the cases of PBC, the splenic weight was positively correlated with the liver weight. There was no significant difference in the splenic weight between the cases belonging to histologic stages 1-3 and those of stage 4. Fibrosis extending from the splenic trabecula, proliferation and dilatation of the splenic sinus, and congestion in the red pulp, all being compatible with chronic splenic congestion, were similarly observed in the spleen in PBC as well as in other non-biliary cirrhotic cases. The present study indicates that the PBC patients present splenomegaly in the non-cirrhotic histologic stage and splenomegaly persists thereafter. However, the histopathologic changes of the spleen peculiar to PBC were not specified in this autopsy study. Prolonged portal hypertension and other mechanisms, possibly related to immune disarrangement, may be responsible for the prominent splenomegaly in PBC.

Immunohistochemical analysis of S-phase cells in normal human and rat liver by PC10 monoclonal antibody

The expression of proliferating cell nuclear antigen (PCNA) was examined in normal human and rat liver fixed in either formaldehyde or methanol, and was compared with the incorporation of bromodeoxyuridine (BrdU) in S-phase cells. Codistribution of PCNA and BrdU was assessed in rat liver by double immunohistochemical staining using PC10 and anti-BrdU monoclonal antibodies to identify labelled nuclei of parenchymal and sinusoidal cells. In formaldehyde-fixed human biopsies (n = 13) PCNA-labelling index (PCNA LI) was 0.43 +/- 0.24% (mean +/- SEM) for hepatocytes and 0.09 +/- 0.03% for sinusoidal cells. A great interspecimen variability was observed and a preferential lobular distribution was not evident. In methanol-fixed human liver (n = 8) the immunostaining was strong. PCNA LI was 0.05 +/- 0.01% for hepatocytes and 0.14 +/- 0.01% for sinusoidal cells. 75% of labelled hepatocytes and 60% of labelled sinusoidal cells were found in acinar zone 1. In formaldehyde-fixed rat liver (n = 10) a weak nuclear staining and a great interspecimen variability were evident. LI was 0.13 +/- 0.07% for hepatocytes and 0.40 +/- 0.21% for sinusoidal cells without preferential acinar distribution. In methanol-fixed rat liver (n = 10), PCNA LI was 0.14 +/- 0.02% for hepatocytes and 0.40 +/- 0.04% for sinusoidal cells. 64% of labelled hepatocytes and 50% of labelled sinusoidal cells were found in zone 1. Only on methanol-fixed material did double immunohistochemistry show an almost complete overlap of BrdU and PCNA labelling. The PCNA LIs and the zonal distribution of labelled nuclei as obtained in methanol-fixed material are in keeping with previous reports using 3H-thymidine (3H-Thy) incorporation, suggesting that PCNA immunostaining represents a valid alternative to 3H-Thy.(ABSTRACT TRUNCATED AT 250 WORDS)

Clinicopathological study of proliferating cell nuclear antigen (PCNA) of hepatocytes in primary biliary cirrhosis

The DNA synthesis activities of hepatocytes in primary biliary cirrhosis (PBC) and other chronic liver diseases and control subjects were examined by staining proliferating cell nuclear antigen (PCNA) with anti-PCNA monoclonal antibody. The number of PCNA-positive cells (PCNA value) was significantly higher in PBC (375 +/- 281 parts per thousand; ppt) than in other chronic liver diseases, i.e., chronic hepatitis (95 +/- 83 ppt), liver cirrhosis (72 +/- 71 ppt), and alcoholic liver disease (73 +/- 56 ppt), and in control subjects (11 +/- 14 ppt). The PCNA value of PBC in stages I-III of Scheuer's classification was remarkably high, while in stage IV it was low. Even in identical, Scheuer's stages, the PCNA value of PBC was higher in patients who were not given ursodeoxycholic acid (UDCA) than in those who received UDCA. In identical patients, the PCNA value was lowered significantly after UDCA treatment. It was concluded that the DNA synthesis activity of PBC in stages I-III was accelerated and that UDCA can alleviate the abnormality in DNA synthesis activity.

Unusual hepatocellular lesions in primary biliary cirrhosis resembling but unrelated to hepatocellular neoplasms

Structural, cellular and nuclear abnormalities of hepatocytes are a histological hallmark of well-differentiated, small hepatocellular carcinoma (HCC) or its borderline lesion. This study revealed that several hepatocellular abnormalities found in these hepatocellular neoplasms were also found in non-cirrhotic stages of primary biliary cirrhosis (PBC) in which HCC is unlikely to develop. These changes are small cell changes, consisting of the appearance of small hepatocytes arranged in thin trabecular or compact patterns with increased cellularity and basophilic cytoplasm. This was found in 36%, 71% and 100% in specimens of stages 1, 2 and 3, respectively. Large cell changes occurred and consisted of large hepatocytes with large nuclei and prominent nucleoli, found in 27%, 47% and 22% of the stages, respectively. Finally, liver cell rosettes were seen, showing variable acinar formation and present in 0%, 41% and 33% of the stages, respectively. These lesions were identified microscopically as irregularly shaped areas or vague nodules of hepatocytes without a fibrous rim, in the hepatic lobules. They showed an expansive growth or shaggy border against the surrounding hepatic parenchyma. Follow-up studies, including autopsies, failed to show development of HCC or its borderline lesion in PBC cases. Pathologists must make a diagnosis of HCC and its borderline lesion bearing in mind the occurrence of such unusual hepatocellular lesions probably of a reactive nature.