Myofibroblasts in the cirrhotic rat liver reflect hepatic remodeling and correlate with fibrosis and sinusoidal capillarization

BACKGROUND/AIMS

Myofibroblasts are essential in fibrogenesis during development of cirrhosis. In the present study we stereologically quantitated MFB's and correlated them with fibrosis and sinusoidal capillarization.

METHODS

Male SD rats were rendered cirrhotic by chronic exposure to phenobarbital/CCl4, (CIR; n = 16); untreated littermates served as controls (CTR; n = 10). Sinusoidal capillarization was assessed by a multiple indicator dilution technique as previously described. The volume fractions of myofibroblasts and other liver components were estimated by morphometry.

RESULTS

Myofibroblasts averaged 15.7 +/- SD 0.7% in CIR as compared to 6.7% +/- SD 0.4% in CTR (p < 0.01). An extra-littoral compartment of myofibroblasts was found in portal tracts and within fibrous septa. In CIR, hepatocytes showed a bimodal distribution of volume fractions, and hepatocyte volume distribution disclosed a mirror image of that of myofibroblasts. Connective tissue was markedly increased in CIR, averaging 13.2 +/- 1.2% in CIR vs. 1.2 +/- 0.3% in CTR (p < 0.0001). Extravascular albumin space--a measure of sinusoidal capillarization--was reduced by 44% in CIR (0.028 +/- 0.017 vs. 0.050 +/- 0.010 ml/g; p < 0.001). The volume fraction of myofibroblasts correlated best with extravascular albumin space (r = -0.84, p < 0.001). Multiple regression analysis selected only extravascular albumin space and connective tissue to be determined by the volume fraction of myofibroblasts (r = 0.923; p < 0.001).

CONCLUSION

We conclude that increased myofibroblasts reflect the degree of hepatic remodeling rather than cirrhosis inasmuch as myofibroblast volume fraction inversely reflects that of hepatocyte bimodality. Myofibroblasts form an extra-littoral compartment in this model of CIR and correlate with hepatic fibrosis and sinusoidal capillarization.

Transforming growth factor betas and their signaling receptors in human hepatocellular carcinoma

BACKGROUND

Transforming growth factor betas (TGF-betas) are multifunctional polypeptides that have been suggested to influence tumor growth. They mediate their functions via specific cell surface receptors (type I ALK5 and type II TGF-beta receptors). The aim of this study was to analyze the roles of the three TGF-betas and their signaling receptors in human hepatocellular carcinoma (HCC).

METHODS

HCC tissue samples were obtained from 18 patients undergoing partial liver resection. Normal liver tissues from 7 females and 3 males served as controls. The tissues for histological analysis were fixed in Bouin's solution and paraffin embedded. For RNA analysis, freshly obtained tissue samples were snap frozen in liquid nitrogen and stored at -80 degrees C until used. Northern blot analysis was used in normal liver and HCC to examine the expression of TGF-beta1, -beta2, -beta3 and their receptors: type I ALK5 (TbetaR-I ALK5), type II (TbetaR-II), and type III (TbetaR-III). Immunohistochemistry was performed to localize the corresponding proteins.

RESULTS

All three TGF-betas demonstrated a marked mRNA overexpression in HCC in comparison with normal controls, whereas the levels of all three TGF-beta receptors showed no significant changes. Intense TGF-beta1, TGF-beta2, and TGF-beta3 immunostaining was found in hepatocellular carcinoma cells and in the perineoplastic stroma with immunohistochemistry, whereas no or mild immunostaining was present in the normal liver. For TbetaR-I ALK5 and TbetaR-II, the immunostaining in both HCC and normal liver was mild to moderate, with a slightly higher intensity in the normal tissues.

CONCLUSION

The upregulation of TGF-betas in HCC suggests an important role for these isoforms in hepatic carcinogenesis and tumor progression. Moreover, the localization of the immunoreactivity in both malignant hepatocytes and stromal cells suggests that TGF-betas act via autocrine and paracrine pathways in this neoplasm.

ErbB-4 mRNA expression is decreased in non-metastatic pancreatic cancer

The erbB-4 gene encodes a detected receptor protein that possesses intrinsic tyrosine kinase activity and belongs to the family of the epidermal growth factor receptor (EGFR); erbB-4 is stimulated by the heregulins and betacellulin, which enables this receptor to form heterodimers with erbB-2, a prerequisite for erbB-2 activation. Because the expression of erbB-4 mRNA is generally low in the pancreas, quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) was used to determine the erbB-4 levels in human normal and cancerous pancreatic tissue. Our results show that the mRNA expression of this receptor is 6-fold decreased in the non-metastatic stages of pancreatic cancer when compared to tumors with lymph node or distant metastases or to the normal pancreas. In addition, immunohistochemistry demonstrated that in the normal pancreas, the erbB-4 antigen was predominantly present in the cell membrane and cytoplasm of the ductal and acinar cells and at a much lower level, in islet cells. In pancreatic cancer, 61 of 75 samples exhibited weak to moderate immunoreactivity for erbB-4 in the tumor cells. Moreover, in the peri-tumorous region with chronic pancreatitis-like morphological changes, there was weak-to-moderate erbB-4 immunostaining in small ductules and degenerating acinar cells. Uni- and multivariate survival analyses using as variables age, sex, stage of cancer, histo-pathological grading, and erbB-4 immunoreactivity, revealed a significant effect for stage of cancer (p < 0.01) whereby the risk of dying was 2.3 times higher in patients with metastases than in patients without. However, the level of erbB-4 immunoreactivity in pancreatic cancer cells had no influence on patient survival.

Intrapancreatic accessory spleen. A rare cause of a pancreatic mass

CONCLUSION

The clinical significance of intrapancreatic accessory spleens resides in the mimicry of pancreatic cancer. Radionuclide tests (Octreotide scan and Tc99m sulfur colloid scan) should be undertaken to distinguish these lesions from neuroendocrine tumors, hypervascular metastases and pancreatic carcinoma. If the tests are equivocal, diagnostic laparotomy or laparoscopy is recommended.

BACKGROUND

Despite its relatively common occurrence, intrapancreatic ectopic splenic tissue is rarely detected owing to its asymptomatic nature.

METHODS

We report a case of a clinically asymptomatic patient in which abdominal computed tomography (CT) scans revealed a mass of 1.5 cm in diameter in the distal pancreas. The tumor markers CA 19-9 and carcinoembryonic antigen (CEA) were slightly elevated, and pancreatic neoplasm was suspected.

RESULTS

Left pancreatic resection and splenectomy were performed. The removed specimen disclosed the presence of an accessory spleen within the pancreatic tail.

Apoptosis inhibiting factor Bcl-xL might be the crucial member of the Bcl-2 gene family in colorectal cancer

Since the role of the Bcl-2 gene family has been only poorly investigated in colorectal cancer, we have examined the expression of the apoptosis blockers Bcl-xL and Bcl-2, as well as the proapoptotic factors Bax and Bak. Northern blot analysis and immunohistochemistry were performed on normal and cancerous colonic tissue from 12 patients. In colorectal cancer, Bcl-xL immunoreaction was stronger than in normal controls, and 83% of the cancers had increased Bcl-xL mRNA expression. The median densitometric Bcl-xL values were 3.4-fold higher in carcinomas (P<0.005). In contrast to the normal colon, colorectal carcinomas often lack any Bcl-2 immunostaining, and Bcl-2 mRNA was not detectable by Northern blots either. Bax was not obviously altered in colorectal cancer, either at the protein level or at the mRNA level compared to the normal control colon. Bak mRNA expression exhibited a wide variation in carcinomas, but was somewhat decreased in comparison to the controls. Of these members of the Bcl-2 gene family, Bcl-xL seems to play a major role in colorectal tumorigenesis and disease progression. An agonistic effect might have caused the tendency for reduced Bak expression. The Bcl-2/Bax regulation system of cell homeostasis seems to be of lesser importance.

Transforming growth factor-betas and their signaling receptors are coexpressed in Crohn's disease

OBJECTIVE

To evaluate mechanisms that contribute to tissue repair and tissue remodeling in Crohn's disease (CD).

SUMMARY BACKGROUND DATA

Transforming growth factor-betas (TGF-betas) are involved in different chronic inflammatory disorders. They function by binding to two receptors, type I (TbetaR-I) subtype ALK5 and type II (TbetaR-II), which are concomitantly required for signal transduction.

METHODS

Tissues were obtained from 18 patients with CD (10 female patients, 8 male patients, median age 38.7 years [range 16 to 58 years]) undergoing surgery because of CD-related complications. Tissue samples of 18 healthy organ donors (10 female subjects, 8 male subjects, median age 50.3 years [range 15 to 65 years]) served as controls. The expression and localization of TGF-beta1, TGF-beta2, TGF-beta3, TbetaR-IALK5, TbetaR-II, and TbetaR-III were studied by Northern blot analysis, in situ hybridization, and immunohistochemistry.

RESULTS

On Northern blot analysis, 94% of the CD samples exhibited enhanced TGF-beta1, TGF-beta3, and TbetaR-II mRNA expression compared with controls. TGF-beta2 was increased in 72%, TbetaR-IALK5 in 72%, and TbetaR-III in 82% of the patients with CD. On in situ hybridization and immunohistochemical analysis, TGF-beta1, TbetaR-IALK5, and TbetaR-II were seen to be colocalized in the lamina propria cells and in the lymphocytes closest to the luminal surface, but also in the remaining epithelial cells, and in fibroblasts of CD tissue samples.

CONCLUSIONS

The concomitant overexpression of TGF-betas and their signaling receptors in CD points to a potential role of these regulatory molecules in the pathophysiology of CD. Activation of TGF-beta-mediated pathways might promote the repair of mucosal injury by enhancing the process of reepithelization, but might also contribute to extracellular matrix generation and subsequently to intramural fibrosis and intestinal obstruction.

Bak expression and cell death occur in peritumorous tissue but not in pancreatic cancer cells

Bak is a pro-apoptotic member of the Bcl-2 family whose genes are involved in regulation of programmed cell death. Using in situ hybridization, immunohistochemistry, and Northern blot analysis, we studied the expression of Bak in specimens from 12 normal pancreata and 26 primary pancreatic cancers, and correlated the findings with the clinical and histopathologic data of the patients. By comparison with normal pancreas, Northern blot analysis demonstrated a 2.5-fold increase of Bak messenger RNA expression in the tumor samples (P <0. 001). Elevated levels were found in 15 of the 26 pancreatic cancer tissue specimens. In these samples Bak expression was increased 4.3 fold (P <0.001). No association was detected between Bak expression and tumor stage. In situ hybridization and immunohistochemistry revealed that the tumor cells themselves and the stroma cells expressed only low levels of Bak. In contrast, in regions adjacent to the tumor, which showed chronic inflammation, there was always high expression in the acinar and inflammatory cells, explaining the increased Bak levels found in the tumor samples by means of Northern blot analysis. In the normal pancreas the expression of Bak was generally moderate in the acinar cells and low in the ductal and islet cells. In situ analysis using the terminal deoxynucleotidyl transferase method further showed that there was extensive cell death in the peritumorous areas with chronic inflammation. Taken together, these results suggest that in pancreatic cancer Bak expression and programmed cell death are present in cells that are localized in regions of chronic inflammation surrounding the pancreatic cancer cells but not in the tumor cells themselves, a situation that may facilitate tumor growth and spread.

KAI1, a new metastasis suppressor gene, is reduced in metastatic hepatocellular carcinoma

Down-regulation of KAI1 expression has been shown to be associated with formation of metastases or disease progression in prostate and pancreatic cancer. In the present study we analyzed the expression pattern of KAI1 in metastatic and nonmetastatic hepatocellular carcinomas (HCCs) in comparison with normal livers to evaluate whether alteration of KAI1 also facilitates the metastatic ability in this malignancy. Thirty-nine primary HCCs and 10 normal liver tissue samples were studied for KAI1 messenger RNA (mRNA) expression with use of Northern blot analysis and in situ hybridization. By Northern blot analysis, moderate to strong KAI1 mRNA expression was present in normal liver samples. In contrast, KAI1 mRNA expression in tissue samples of primary HCCs was markedly decreased compared with normal controls. The normal/tumor ratio of KAI1 mRNA expression was 2.6:1 (P <.01). Primary HCCs that gave rise to metastasis showed significantly lower KAI1 mRNA levels than nonmetastasized HCCs (P <. 05). As seen by in situ hybridization, moderate to strong cytoplasmic KAI1 mRNA staining was present in almost all normal hepatocytes. Bile ducts, blood vessels, and connective tissue showed no or only faint KAI1 mRNA expression in the normal liver samples. In nonmetastatic HCCs, the cancer cells exhibited in situ hybridization signals that were similar to the normal controls. In contrast, most of the primary HCC cells in samples with metastases showed only faint or moderate KAI1 mRNA expression predominantly in the perinuclear regions. When KAI1 mRNA expression of primary hepatocellular cancer cells was compared with metastasized cancer cells in lymph nodes, with intrahepatic satellite metastasis, or with peritoneal metastasis in the same patients, significantly lower (P <.01) KAI1 mRNA levels were present in the metastasized HCC cells. Reduced KAI1 mRNA in HCC cells seems to influence their metastatic ability and thereby enhances the malignant potential of HCC.

Transforming growth factor betas and their receptors in human liver cirrhosis

BACKGROUND

Transforming growth factor betas (TGF-betas) are a group of homologous polypeptides that exert pleiotropic effects on various cell types and stimulate the formation of extracellular matrix and fibrosis. To evaluate whether TGF-beta isoforms (TGF-beta1, TGF-beta2 and TGF-beta3) and their receptors (types I-III) are also of importance in the pathophysiology of liver cirrhosis, we analysed their concomitant expression and localization in human liver cirrhosis.

PATIENTS

Cirrhotic liver tissue samples were obtained from 17 patients (four women, 13 men) with a median age of 41 years (range 22-67). Normal liver tissues from ten patients (seven women, three men) with a median age of 55 years (range 45-75) served as controls.

METHODS

The tissues were fixed in Bouin's solution and paraffin-embedded for histological analysis. For RNA analysis, freshly obtained tissue samples were snap-frozen in liquid nitrogen and stored at -80 degrees C until analysed. Northern blot analysis was used to examine the expression of TGF-beta1, beta2 and beta3 and their receptors, type I (TbetaR-I), type II (TbetaR-II) and type III (TbetaR-III). Immunohistochemistry was performed to determine the localization of the corresponding proteins in the normal and the cirrhotic liver.

RESULTS

Northern blot analysis revealed enhanced expression (P < 0.05) of TGF-beta1 (twofold increase), TGF-beta2 (threefold increase) and TGF-beta3 (8.5-fold increase) and of TbetaR-II (threefold increase) mRNA in liver cirrhosis in comparison with normal controls. In contrast, TbetaR-I (ALK-5) and TbetaR-III mRNA expression showed no significant changes. No TGF-beta isoform immunoreactivity was present in hepatocytes in either normal livers or in liver cirrhosis. However, in liver cirrhosis, intense TGF-beta1 immunoreactivity was present in bile duct and ductular epithelial cells (including ductular proliferations) and in inflammatory cells. In a few sinusoidal lining cells, faint TGF-beta1 and moderate TGF-beta2 immunoreactivity was present. TGF-beta3 immunostaining was present in bile duct and ductular epithelial cells, in inflammatory cells and in fibroblast-like spindle cells in liver cirrhosis. For TbetaR-I and TbetaR-II, the immunoreactivity was localized in hepatocytes and biliary cells in normal and cirrhotic liver tissues, with higher intensity for TbetaR-II in the cirrhotic liver.

CONCLUSION

Enhanced expression of all three TGF-bea isoforms and of TbetaR-II in liver cirrhosis suggests their involvement in this fibrotic disorder. The higher immunoreactivity of the three TGF-beta isoforms in the bile duct epithelial cells in cirrhotic tissues suggests a possible role of these cells in the pathogenesis of liver cirrhosis.

Moderate activation of the apoptosis inhibitor bcl-xL worsens the prognosis in pancreatic cancer

OBJECTIVE

To analyze the expression of the antiapoptotic gene bcl-xL in human pancreatic cancer and to correlate the results with clinical patient parameters.

SUMMARY BACKGROUND DATA

Bcl-xL belongs to the bcl-2-related gene family and acts as a broad antiapoptotic factor to extend both normal and tumor cell survival. Recent findings indicate that tumor cell death induced by chemotherapy and radiotherapy is mediated by the activation of apoptosis. The fact that pancreatic cancer has an extremely malignant potential and that it is resistant to most anticancer treatment modalities suggests that mechanisms are activated that increase the viability of pancreatic cancer cells.

METHODS

Seventy-four pancreatic cancer tissue samples were obtained from 32 female and 42 male patients undergoing surgery for exocrine pancreatic cancer. Normal human pancreatic tissue samples were available from 11 organ donors and 4 patients without pancreatic disease. The levels of bcl-xL mRNA expression were analyzed by Northern blot analysis. The exact site of bcl-xL mRNA transcription was determined by nonradioactive in situ hybridization. In addition, immunohistochemistry using specific polyclonal antibodies was used to localize the protein.

RESULTS

Northern blot analysis indicated that, in comparison with the normal pancreas, bcl-xL mRNA was markedly overexpressed in 54% of the pancreatic cancer samples. Densitometric analysis revealed that pancreatic adenocarcinomas exhibited a mean 3.4-fold increase (p < 0.01) in bcl-xL mRNA levels in comparison with normal controls. With in situ hybridization, bcl-xL mRNA was found to be highly expressed in the cancer cells of tumor samples that exhibited increased mRNA expression by Northern blot analysis. Immunohistochemical analysis revealed bcl-x immunostaining in 88% of the cancer samples. Correlation of the molecular data with clinical patient parameters revealed that patients whose tumors exhibited no, faint, or weak bcl-xL expression lived significantly longer after tumor resection (median 12 months) than patients whose tumors exhibited moderate bcl-xL mRNA expression (median 5 months) (p < 0.05). However, 5 patients whose tumors exhibited intense bcl-xL mRNA expression tended to live longer (median 14 months).

CONCLUSION

Enhanced expression of the antiapoptotic gene bcl-xL in pancreatic cancer and its association with shorter patient survival suggests that this factor may enhance the viability of pancreatic cancer cells in vivo. Inhibition of apoptotic pathways might be one of the reasons why pancreatic cancer shows only limited sensitivity to anticancer treatment.

Ureaplasma urealyticum colonization and bronchopulmonary dysplasia: a comparative prospective multicentre study

To determine the role of tracheal colonization at birth with Ureaplasma urealyticum and other pathogenic bacteria with regard to the development of bronchopulmonary dysplasia (BPD), 97 premature infants with very low birth weight (< 1500 g) were followed prospectively over 30 days in a multicentre study. Of those infants, 35 were colonized with Ureaplasma urealyticum (group Ia), 22 with other pathogenic bacteria (group Ib) and 40 infants with sterile tracheal aspirates served as controls (group II). Colonization with Ureaplasma urealyticum or with pathogenic bacteria independently increased the risk of developing BPD as compared to the controls (OR 2.55; 95% CI [1.11, 5.87]). Among Ureaplasma urealyticum and bacterial colonized infants, duration of mechanical ventilation and oxygen requirement were significantly longer than among controls (P < 0.05); during the interval of 11 to 35 days of life, every additional day of ventilation significantly increased the risk of BPD (OR 1.22; CI [1.12, 1.32]). The rate of oxygen supplementation, which was similar in both groups during the first 2 weeks of life, was significantly higher among the colonized infants at day 21 (0.38+/-0.18 and 0.39+/-0.16 vs 0.31+/-0.13, P < 0.05) and at day 28 (0.38+/-0.21 and 0.34+/-0.15 vs 0.28+/-0.12, P < 0.05). For infants still ventilated at age of 28 days, Ureaplasma urealytricum and bacterial colonization were associated with a significant higher risk for BPD than for uncolonized controls (OR 5.53; [1.27, 24.02]. Association of Ureaplasma urealyticum and of bacterial colonization and BPD was not weakened after adjustments were made in a multivariate analysis for other significant risk factors.

CONCLUSION

Ureaplasma urealyticum colonization is as an important risk factor in the development of bronchopulmonary dysplasia as bacterial colonization even after treatment with surfactant.

Apoptosis inhibiting factor Bcl-xL might be the crucial member of the Bcl-2 gene family in colorectal cancer

Since the role of the Bcl-2 gene family has been only poorly investigated in colorectal cancer, we have examined the expression of the apoptosis blockers Bcl-xL and Bcl-2, as well as the proapoptotic factors Bax and Bak. Northern blot analysis and immunohistochemistry were performed on normal and cancerous colonic tissue from 12 patients. In colorectal cancer, Bcl-xL immunoreaction was stronger than in normal controls, and 83% of the cancers had increased Bcl-xL mRNA expression. The median densitometric Bcl-xL values were 3.4-fold higher in carcinomas (P<0.005). In contrast to the normal colon, colorectal carcinomas often lack any Bcl-2 immunostaining, and Bcl-2 mRNA was not detectable by Northern blots either. Bax was not obviously altered in colorectal cancer, either at the protein level or at the mRNA level compared to the normal control colon. Bak mRNA expression exhibited a wide variation in carcinomas, but was somewhat decreased in comparison to the controls. Of these members of the Bcl-2 gene family, Bcl-xL seems to play a major role in colorectal tumorigenesis and disease progression. An agonistic effect might have caused the tendency for reduced Bak expression. The Bcl-2/Bax regulation system of cell homeostasis seems to be of lesser importance.

[Severe hepatocellular damage after administration of paracetamol and chlorzoxazone in therapeutic dosage]

A 64 year old patient developed severe hepatocellular damage with jaundice and coagulopathy during ingestion of a combination of paracetamol and chlorzoxazone in therapeutic dosage. The risk factors for the development of liver cell necrosis following ingestion of paracetamol in therapeutic dosage are discussed. In particular in patients with risk factors (e.g. alcoholics and patients with heart failure) paracetamol-induced liver failure has to be considered in the presence of high transaminases, even when paracetamol was ingested in therapeutic dosage. Chlorzoxazone itself rarely can induce an idiosyncratic hepatocellular damage.

Functional regions of the human cytomegalovirus protein pUL97 involved in nuclear localization and phosphorylation of ganciclovir and pUL97 itself

In order to identify functional regions of the human cytomegalovirus protein pUL97 (i) different 5' fragments of the UL97 open reading frame (ORF) were fused to the coding region of the green fluorescent protein and (ii) recombinant vaccinia viruses (rVV) were generated carrying two full-length and 11 mutated UL97 ORFs. The results indicated the presence of an N-terminal region within pUL97 which changed the intracellular distribution of the fusion proteins. pUL97 was localized in the nucleus, but not in the nucleoli, and was detected in the nuclear matrix fraction. Expression of all pUL97 mutants could be confirmed by Western blot analysis. pUL97-associated ganciclovir (GCV) phosphorylation in rVV-infected cells, determined quantitatively by HPLC analysis, was abolished completely using individual UL97 deletion mutants. Phosphorylation of full-length and some of the mutated pUL97 was detected in cells infected with the rVVs. The UL97 constructs carrying point mutations from GCV-resistant HCMV isolates at positions 460M, 520H, 594V, and the 4 aa deletion 590AACR593, also resulted in decreased but not abolished phosphorylation of GCV in the rVV system, whereas the phosphorylation of pUL97 itself was not influenced. The rVV system is a suitable method for quantitatively testing the functional relevance of pUL97 mutations.

bax, but not bcl-2, influences the prognosis of human pancreatic cancer

BACKGROUND

bcl-2 and bax belong to the bcl-2-related gene family, which marks a new class of genes that influence apoptosis. The bcl-2 oncogene acts as a broad antiapoptotic factor and extends both normal and tumour cell survival. In contrast, the bax gene is a promoter of apoptosis.

AIMS

To analyse the expression of bcl-2 and bax in pancreatic cancer and correlate the results with clinical parameters.

PATIENTS

Pancreatic cancer tissue samples were obtained from 28 female and 32 male patients (median age 63, range 43-79 years) having surgery for pancreatic cancer. Normal pancreatic tissues obtained from 18 previously healthy organ donors served as controls.

METHODS

The levels of bcl-2 and bax mRNA expression were analysed by northern blot and the exact site of mRNA transcription was determined by in situ hybridisation. The presence of the corresponding proteins was determined by immunohistochemistry.

RESULTS

Northern blot analysis indicated that, in comparison with the normal pancreas, bcl-2 mRNA was overexpressed in 30% and bax mRNA in 61% of the pancreatic cancer samples. Concomitant overexpression of bcl-2 and bax was present in 26% of the cancer samples. Pancreatic adenocarcinomas exhibited 3.7-fold and 5.4-fold increases (p < 0.001) in bcl-2 and bax mRNA levels respectively. In situ hybridisation showed that both bcl-2 and bax mRNA were expressed in the cancer cells. Immunohistochemical analysis showed positive Bcl-2 and Bax immunostaining in 28 and 83% of the cancer samples respectively. In multivariate analysis (Cox regression model), bax expression was found to be a strong indicator of survival (p < 0.001). Patients whose tumours exhibited Bax immunostaining lived significantly longer (12 months) than those whose tumours were Bax negative (five months) (p < 0.039). In contrast, no relation was found between Bcl-2 and survival time.

CONCLUSIONS

The data indicate that genes that are involved in the regulation of apoptosis are upregulated in human pancreatic cancer cells. Prolonged survival times in patients in whom apoptosis promoting factors are upregulated indicate that apoptotic pathways are of biological significance in pancreatic cancer.

Reduced KAI1 expression in pancreatic cancer is associated with lymph node and distant metastases

KAI1 belongs to a structurally distinct family of membrane glycoproteins, which function via cell-cell and cell-extracellular matrix interactions, thereby potentially influencing the ability of cancer cells to invade tissues and to metastasize into lymph nodes and distant organs. In the present study, we examined KAI1 expression in lymph node and liver metastases in comparison with primary pancreatic cancer to evaluate its influence on metastasis. KAI1 mRNA analysis was performed by Northern blot analysis and in situ hybridization. In addition, the respective protein was studied by immunostaining. Fourteen primary pancreatic cancer samples in which no lymph node metastases were present and 25 primary pancreatic cancer samples in which lymph node metastases were present at the time of tumor resection were included. In 20 of these cases, primary pancreatic cancer tissues and corresponding lymph node metastases from the same patient were studied. Furthermore, 11 liver metastases were available for KAI1 analysis. Increased steady-state levels of KAI1 mRNA were found in 33/39 (85%) primary pancreatic cancers in comparison with normal controls. Statistical analysis of KAI1 mRNA levels and clinical parameters of the patients revealed that KAI1 mRNA levels were significantly higher in non-metastasized tumors compared with tumors in which lymph node or distant metastases were present. In lymph node metastases KAI1 mRNA expression was lower than in the corresponding primary tumors: In 14 of 20 lymph node metastases no KAI1 mRNA expression and in 6 of 20 lymph node metastases only weak KAI1 mRNA levels were present in some cancer cells. Cancer cells of distant metastases were devoid of or exhibited low KAI1 mRNA levels compared with those of primary pancreatic cancers. A similar pattern was observed by immunostaining. These data support the hypothesis that KAI1 gene expression might influence the metastatic ability of pancreatic cancer cells in vivo. Reduction of KAI1 appears to promote cancer cell spread in lymph nodes and distant organs.

Reduced KAI1 expression in pancreatic cancer is associated with lymph node and distant metastases

KAI1 belongs to a structurally distinct family of membrane glycoproteins, which function via cell-cell and cell-extracellular matrix interactions, thereby potentially influencing the ability of cancer cells to invade tissues and to metastasize into lymph nodes and distant organs. In the present study, we examined KAI1 expression in lymph node and liver metastases in comparison with primary pancreatic cancer to evaluate its influence on metastasis. KAI1 mRNA analysis was performed by Northern blot analysis and in situ hybridization. In addition, the respective protein was studied by immunostaining. Fourteen primary pancreatic cancer samples in which no lymph node metastases were present and 25 primary pancreatic cancer samples in which lymph node metastases were present at the time of tumor resection were included. In 20 of these cases, primary pancreatic cancer tissues and corresponding lymph node metastases from the same patient were studied. Furthermore, 11 liver metastases were available for KAI1 analysis. Increased steady-state levels of KAI1 mRNA were found in 33/39 (85%) primary pancreatic cancers in comparison with normal controls. Statistical analysis of KAI1 mRNA levels and clinical parameters of the patients revealed that KAI1 mRNA levels were significantly higher in non-metastasized tumors compared with tumors in which lymph node or distant metastases were present. In lymph node metastases KAI1 mRNA expression was lower than in the corresponding primary tumors: In 14 of 20 lymph node metastases no KAI1 mRNA expression and in 6 of 20 lymph node metastases only weak KAI1 mRNA levels were present in some cancer cells. Cancer cells of distant metastases were devoid of or exhibited low KAI1 mRNA levels compared with those of primary pancreatic cancers. A similar pattern was observed by immunostaining. These data support the hypothesis that KAI1 gene expression might influence the metastatic ability of pancreatic cancer cells in vivo. Reduction of KAI1 appears to promote cancer cell spread in lymph nodes and distant organs.

Increased expression of erbB3 in colorectal cancer is associated with concomitant increase in the level of erbB2

ErbB3 is a transmembrane signaling molecule that shares close structural homology with epidermal growth factor receptor (EGFR), erbB2, and erbB4. They have all been implicated in cell transformation and tumor pathogenesis, but very little is known about the role of erbB3 in normal colon and colorectal cancer. Therefore, in the current study, we determined whether erbB3 is found in normal human colon and whether its expression is altered in colorectal cancer. Because of some evidence that erbB3 might interact with erbB2 and EGFR, respectively, by heterodimerization, we also included erbB2 and EGFR analysis with special regard to coexpression. The study was performed on 35 patients operated on for colorectal carcinoma. The normal human colon showed weak erbB3 and erbB2 immunostaining, predominantly in surface epithelial cells. EGFR immunoreactivity in normal colon varied from weak to strong. In contrast, in 31 of 35 (89%) and in 29 of 35 (83%) colonic cancers, moderate to strong immunoreactivity for erbB3 and erbB2, respectively, was present in most epithelial cancer cells. A concomitant erbB3 and erbB2 immunostaining advantage could be found in 77% of cancerous tissues in comparison with the normal colon. No difference in EGFR immunostaining was evident between normal colon and cancer. Northern blot analysis showed an increase in erbB3 and erbB2 mRNA levels in 64% of cancers in comparison with normal colon samples. By densitometry, 2.3-fold and a 1.5-fold significant increases in erbB3 and erbB2 mRNA levels, respectively, were calculated in the cancerous tissues. Eighty-five percent of cancers with erbB3 mRNA overexpression showed an increase in erbB2 mRNA. Southern blot analysis did not indicate any gene amplification or rearrangement responsible for erbB2 or erbB3 overexpression. EGFR, however, was decreased in cancer on mRNA level. These findings indicate that erbB2 and erbB3, but not EGFR, may contribute to tumor growth and disease progression in colon cancer. The correlation between increased erbB2 and erbB3 expression in both Northern blots and immunohistochemical analysis suggests a co-overexpression of erbB2 and erbB3 and might support the hypothesis that these two growth factor receptors act together by heterodimer formation.

Liver cell dysplasia: reactivities for c-met protein, Rb protein, E-cadherin and transforming growth factor-beta 1 in comparison with hepatocellular carcinoma

In the present retrospective study, liver cell dysplasia (LCD) occurring in cirrhotic livers associated or not associated with hepatocellular carcinoma (HCC) was immunohistochemically analyzed for the expression of hepatocyte growth factor receptor (c-met protein), Rb (retinoblastoma gene) protein, E-cadherin, and transforming growth factor-beta-1 (TGF-beta-1). Cytoplasmic c-met protein staining was observed in about half of the HCC's, and its prevalence was about twice as high in high grade vs. low grade tumors, but it was not correlated with proliferative activity as based on PCNA labelling. In LCD, reactivity for c-met protein was restricted to the small cell type. Nuclear staining for Rb protein was found in HCC's, and was not related to type, grade or proliferative activity, whereas no immunoreactivity was observed in normal, hyperplastic or dysplastic hepatocytes. Expression of E-cadherin prevailed in HCC's of lower grade, and particularly in those with a trabecular or acinar growth pattern. E-cadherin staining was detectable in normal and large dysplastic hepatocytes, but not in small dysplastic liver cells. TGF-beta-1 reactivity was observed in more than half the HCC's, but not in normal or dysplastic hepatocytes. These findings underline the phenotypic difference between large cell and small cell liver dysplasia, and support the hypothesis that small cell dysplasia is a precursor lesion in a hepatocarcinogenic pathway.

The plasminogen activator/plasmin system is up-regulated after acute necrotizing pancreatitis in human beings

BACKGROUND

Proteolysis and formation of new extracellular matrix components are important mechanisms in tissue remodeling and repair. In this study we analyzed the expression and distribution of the urokinase plasminogen activator (uPA), its membrane receptor (urokinase plasminogen activator receptor [uPAR]), and its inhibitor (plasminogen activator inhibitor-1 [PAI-1]) in acute necrotizing pancreatitis in human beings. In addition, we studied the concomitant expression of transforming growth factor-beta-1 (TGF-beta 1), which is activated by uPA from its precursor and is a potent regulator and stimulator of formation of extracellular matrix.

METHODS

With immunohistochemistry and Northern blot analysis, the expression and cellular distribution of uPA, uPAR, PAI-1, and TGF-beta 1 were determined in 12 normal pancreata obtained from organ donors and 12 pancreatic tissues obtained from patients undergoing operation because of complications of acute necrotizing pancreatitis.

RESULTS

Northern blot analysis showed enhanced expression of uPA, uPAR, and PAI-1 in eight of 12, seven of 12, and nine of 12 necrotizing pancreatitis samples, respectively, compared with normal control samples. In addition, increased TGF-beta 1 mRNA expression was present in eight of 12 necrotizing pancreatitis samples. In contrast, amylase mRNA expression was markedly decreased in the samples of acute necrotizing pancreatitis. Immunohistochemistry revealed elevated uPA, uPAR, and PAI-1 immunoreactivity in the remaining acinar and ductal cells adjacent to the necrotic tissue areas. In contrast, acinar and ductal cells that were located farther from pancreatic necrosis exhibited less uPA and uPAR immunoreactivity. A similar staining pattern in samples of necrotizing pancreatitis was found for TGF-beta 1.

CONCLUSIONS

Up-regulation of uPA and uPAR, which activate proteolysis, might create a milieu that enhances lysis and removal of pancreatic necrosis. The increase in TGF-beta 1 might result from the enhanced catalytic conversion of its precursors by uPA, which subsequently might stimulate formation of extracellular matrix, formation of granulation tissue, and fibrosis.

Activation of the serine proteinase system in chronic kidney rejection

BACKGROUND

Activation of the serine proteinase system is an important mechanism that contributes to tissue remodeling. In the present study, we analyzed the expression of urokinase plasminogen activator (uPA), urokinase plasminogen activator receptor (uPAR), and plasminogen activator inhibitor type 1 (PAI-1) in samples of chronically rejected human kidneys.

METHODS

Using Northern blot analysis, immunohistochemistry, and a uPA activity assay, specimens from 10 chronically rejected kidneys and 10 normal kidney samples were analyzed.

RESULTS

By Northern blot analysis, the expression of uPAR and PAI-1 mRNA was 2.9-fold (P<0.05) and 2.3-fold (P<0.05) increased in chronically rejected kidney samples, respectively, compared with normal controls. In contrast, uPA mRNA levels in chronically rejected kidneys were comparable to those in the normal controls. Immunohistochemical analysis in normal kidneys showed weak immunostaining of uPA, moderate to intense uPAR and PAI-1 immunostaining in proximal tubules, and moderate immunostaining in distal tubules, but no signal in the glomeruli or cortical vessels. A similar staining pattern was found in the distal and proximal tubules in rejected kidney tissue samples. However, in the rejected kidneys, the number of tubules was markedly reduced. In addition, within the glomeruli of rejected kidney samples, there was positive immunostaining for uPA, uPAR, and PAI-1 in the mesangial cells, but negative staining in most of the endothelial cells, whereas the normal kidneys revealed no immunoreactivity in these structures.

CONCLUSION

The demonstrated up-regulation of uPA/uPAR/PAI-1 in chronic renal rejection is consistent with the plasminogen/plasmin system contributing to tissue remodeling in this disorder. These factors might activate latent transforming growth factor-betas, which have been reported to be enhanced in this disorder, contributing to the generation of the extracellular matrix.

Effects of tilmicosin on acute undifferentiated respiratory tract disease in newly arrived feedlot cattle

OBJECTIVES

To evaluate effects of tilmicosin when used in fever-based and metaphylactic treatment programs to attenuate acute undifferentiated bovine respiratory disease (BRD) in cattle that recently arrived at feedlots, and to evaluate the effects of tilmicosin for the treatment of BRD.

DESIGN

Randomized-block controlled study.

ANIMALS

1,639 calves from livestock auctions.

PROCEDURES

Cattle were assigned to 3 groups. Cattle in the nonmedicated (control) group were not given antibiotics during processing. Cattle in the fever-based treatment group were given tilmicosin (10 mg/kg [4.5 mg/lb] of body weight, s.c.) during processing when their rectal temperature was > or = 40 C (104 F). All cattle in the metaphylactic treatment group were given tilmicosin (10 mg/kg, s.c.) during processing. Calves with BRD were treated with tilmicosin (10 mg/kg, s.c.).

RESULTS

Morbidity rates in the metaphylactic (30.4%) and fever-based (44.7%) treatment groups were less than that for the nonmedicated group (54.8%). Mortality rate for the metaphylactic group during the first 28 days (1.1%) and during the entire study (1.7%) was less than that for the nonmedicated group (3.3 and 4.6%, respectively). Differences were not observed in therapeutic response rates among calves with BRD that were treated.

CLINICAL IMPLICATIONS

Fever-based and metaphylactic treatment programs that used tilmicosin decreased the prevalence of BRD and improved growth of calves. Metaphylactic treatment decreased the number of fatalities caused by BRD in high-risk calves. Fever-based treatment was less effective than metaphylactic treatment for decreasing the prevalence of BRD in newly arrived cattle.