Search PubMed⌕ Search

Biomedical subjects

H Denk

Publications and source records attributed to H Denk.

At least 19 recordsLinked to original sources
PubMed2006

Are the Mallory bodies and intracellular hyaline bodies in neoplastic and non-neoplastic hepatocytes related?

Mallory bodies (MBs) and intracellular hyaline bodies (IHBs) are cytoplasmic hepatocellular inclusions that consist of aggregated proteins. MBs are characteristically associated with alcoholic and non-alcoholic steatohepatitis, but may also be found in chronic cholestatic and metabolic (eg copper intoxication) diseases and hepatocellular neoplasms, particularly hepatocellular carcinomas. IHBs have hitherto only been described in hepatocellular carcinoma cells. In the present study hepatocellular carcinomas (HCCs) and a case of idiopathic copper toxicosis were evaluated with respect to the presence and mutual relationship of MBs and IHBs. IHBs alone were present in 8.6%, MBs alone in 16.1% and both types of inclusion in 7.5% of HCCs. It is shown that IHBs may also occur in non-neoplastic hepatocytes in association with idiopathic copper toxicosis, together with MBs. In HCCs and idiopathic copper toxicosis, MBs and IHBs may be present within the same cell. Moreover, hybrid inclusions holding an intermediate position between MBs and IHBs regarding light microscopy, ultrastructure and composition exist. MBs and IHBs contain p62, a stress-inducible adapter protein, as the major constituent. In MBs p62 is associated with keratins, whereas classical IHBs lack keratins. Light microscopic, electron microscopic and immunohistochemical data suggest a close pathogenetic relationship between MBs and IHBs. Both types of inclusion are the result of over-expression and accumulation of the stress protein p62. If p62 is induced alone, or at least prevails, IHBs may arise by aggregation. However, if abnormal keratins are present in addition to p62, p62 associates and co-aggregates with keratins, finally leading to classical MBs.

Adaptor Proteins, Signal Transducing↗
PubMed2004

Prognostic relevance of tumour-associated macrophages and von Willebrand factor-positive microvessels in colorectal cancer.

Tumour-associated macrophages (TAM) are involved in tumour angiogenesis and anti-tumour immune response. In colorectal cancer (CRC), an association of high microvascular density (MVD) and unfavourable prognosis has been reported by some investigators. However, heterogeneous patient groups were studied. We, therefore, analysed the correlation between TAM and MVD and the prognostic relevance of MVD, TAM and T lymphocyte infiltration for long-term survival in a homogeneous group of 70 patients with moderately differentiated cancers of the International Union Against Cancer (UICC) stages II and III, who did not receive chemotherapy. MVD was evaluated using immunohistochemistry with antibodies against CD34 and von Willebrand factor (vWF). TAM and T lymphocytes were visualised with antibodies against CD68 and CD3, respectively. Statistical analysis did not reveal a significant correlation between TAM and T lymphocyte numbers and MVD. Multivariate analysis of immunohistochemical data from all CRC patients and the subgroup of patients with UICC stage-II CRC identified TAM- and vWF-positive microvessel numbers as prognostically relevant markers. Low numbers of TAM- and high numbers of vWF-positive microvessels were associated with an unfavourable prognosis. In conclusion, TAM- and vWF-positive microvessel numbers may serve as independent prognostic markers for patients with UICC stage-II and -III CRC and may help to identify patients with an unfavourable prognosis.

Aged↗
PubMed2002

[Drug-induced liver injury].

Drugs may cause acute or chronic liver damage depending on their mode of action. Hepatotoxic drugs include anaesthetics, psychotropic and anticonvulsant drugs, antiinflammatory agents, steroids, antimicrobial agents and cardiovascular drugs as well as antineoplastic agents. Hepatotoxic agents, including drugs, fall into two categories: (i) intrinsic and obligatory liver toxins with dose-dependent and predictable adverse effects, and (ii) facultative (idiosyncratic) hepatotoxins with non-predictable and non-dose-dependent liver toxicity affecting only few exposed individuals. Intrinsic hepatotoxins may either injure hepatocytes directly, e.g. by direct physicochemical effects, or indirectly by interfering with specific metabolic processes. In the idiosyncratic type of liver injury immunologic hypersensitivity reactions or toxic metabolites may be involved. Clinical and morphologic consequences of adverse drug reactions are acute or chronic liver diseases, including parenchymal damage (finally leading to necrosis or apoptosis), steatosis, cholestasis, various types of vascular alterations, granuloma formation and also neoplastic transformation. Thus, drugs are important causes of liver diseases and may account for up to 40% of cases of hepatitis and up to 25% of fulminant hepatic failure. Moreover, drug-induced injury also plays a leading role as cause of acute cholestasis.

Chemical and Drug Induced Liver Injury↗
PubMed2001

[Long-term outcome of stomach carcinoma achieved in an Austrian standard hospital with an oncologic focus].

INTRODUCTION: Although two large prospective and randomized planned European studies failed to show any benefit of radical D2 lymphadenectomy for gastric cancer, the value of radical lymphadenectomy is still a matter of controversy. METHODS: A radical surgical approach principally using D2, D3 lymphadenectomy, as defined by the Japanese Research Society for Gastric Cancer, has been prospectively performed since January 1984. Out of 729 patients with gastric cancer, 521 were surgically treated for potential cure between 1984 and 31 December, 1998. Clinical, histopathological and surgical factors were evaluated for their influence on long-term survival by means of univariate and multivariate analysis. RESULTS: Tumor-specific 5- and 10-year survival rates for all patients were 58.5% and 57.5% for patients who underwent tumor resection 59% and 58%. For operated patients upon with the aim of achieving cures, the tumor-specific 5- and 10-year survival rates were 63.3% and 62.2% and the median survival time was more than 144 months. Postoperative hospital mortality was 7.7%, 4.6% for R0 resected patients, 8.6% for R1,2 resected patients and 21.3% for those undergoing palliative procedures. Multivariate analysis using the Cox model identified an age older than 65, total gastrectomy as well as high pN- and pT category as detrimental factors with an independent influence on survival. CONCLUSION: After updating the long-term results of gastric cancer, as already published earlier, it is impressively obvious that also in a European setting of gastric cancer patients, with a presupposed appropriate surgical technique and experience, very constant cure rates are achievable with comparatively low mortality and morbidity.

Adenocarcinoma↗
PubMed2001

[Chronic cholangitis].

The term chronic cholangitis comprises a heterogeneous group of intra- and/or extrahepatic diseases that may either be bacterially caused or immunologically mediated. In this review, we will focus on the latter and present the clinicopathological and pathogenetic aspects of primary biliary cirrhosis (PBC) and primary sclerosing cholangitis (PSC). The histopathological criteria are defined and differential diagnosis is discussed. Particular emphasis is given to overlap syndromes of PBC and PSC with autoimmune hepatitis. Finally, a diagnostic algorithm is presented.

Bile Ducts, Intrahepatic↗
PubMed2001

[Alcoholic and nonalcoholic steatohepatitis. Histopathologic and pathogenetic considerations].

Alcoholic (ASH) and nonalcoholic (NASH) steatohepatitis show an almost identical morphology. Since the clinical picture is not characteristic, liver biopsy is still the diagnostic gold standard. ASH and NASH are morphologically characterized by a combination of steatosis, hepatocellular injury (ballooning degeneration, apoptosis, necrosis), perivenular and pericellular fibrosis, and inflammation (mostly neutrophils). A definitive differentiation of ASH and NASH is only possible by exclusion of alcohol abuse. Although NASH comprises a syndrome with a multifactorial etiology, adipositas seems to be the most constant associated causal factor. The pathogenesis of both diseases is still unclear. Clinical evidence and experimental studies suggest an important toxic role of reactive oxygen species (oxidative stress). According to our experience, ballooning of hepatocytes is a constant morphologic feature of ASH and NASH and already present in the early stages of disease. Ballooned cells often (but not always) contain Mallory bodies (alcoholic hyalin), which are irregular cytoplasmic inclusions consisting of keratins and nonkeratin components, including ubiquitin. Ballooning is associated with a disturbance and finally almost disappearance of the keratin-intermediate filament cytoskeleton. In our studies on the pathogenesis of ASH and NASH, we concentrated on these cytoskeletal alterations and Mallory body formation. It could be shown that in the early stages overexpression and hyperphosphorylation of keratins take place. Moreover, the 1:1 ratio of keratin type I (keratin 18) and type II (keratin 8) necessary for the assembly of intermediate filaments is disturbed and the equilibrium shifted toward keratin 8. Thus, the pool of soluble keratin 8 increases. The resulting keratin monomers are sensitive to misfolding and either degraded or aggregated as inclusion bodies. If the proteolytic capacity is impaired (e.g., by inhibition of the proteasomal system) in the chronically stressed cell aggregation prevails,finally leading to Mallory body formation. Convincing evidence exists on the basis of clinical and experimental studies that keratins exert a nonskeletal protective function in simple epithelia (e.g., liver cells). Disturbance of the keratin system may thus significantly contribute to cell damage.

Biopsy↗
PubMed2001

Insulinoma of the pancreas with insular-ductular differentiation in its liver metastasis--indication of a common stem-cell origin of the exocrine and endocrine components.

We describe an insulinoma of the pancreas in a 56-year-old patient, which showed insular-ductular differentiation in its liver metastasis. Although the primary tumor was uniformly endocrine in nature with insulin production, the metastasis contained two distinct cell types in organoid arrangement. One cell type was insulin-positive and was arranged in islet-like structures; the other was insulin-negative but distinctly pan-cytokeratin and cytokeratin 7 positive and arranged in ducts. In the primary tumor and the metastasis, the tumor cells were surrounded by a desmoplastic stroma. As to the histogenesis of the tumor and its metastasis, we discuss the following possibilities: (1) the tumor cells might derive from a common stem cell that matures into two phenotypically different cell lines, resembling the situation in embryogenesis and (2) one tumor cell type originates from the other by transdifferentiation (metaplasia). We conclude that the parallel occurrence of endocrine and ductal differentiation supports the concept that, under certain conditions, islet cells and ductular cells may also originate from islets and that mixed endocrine/exocrine pancreatic tumors do not necessarily arise from totipotent duct cells but might also have a primary endocrine cell origin.

Biomarkers, Tumor↗
PubMed2001

Sequence of events in the assembly of Mallory body components in mouse liver: clues to the pathogenesis and significance of Mallory body formation.

BACKGROUND/AIMS: Chronic intoxication of mice with 3,5-diethoxycarbonyl-1,4-dihydrocollidine (DDC) or griseofulvin (GF) results in appearance of Mallory bodies (MBs) and alterations of the keratin cytoskeleton, which are reversible upon drug withdrawal but recur after readministration within 2-3 days. METHODS: DDC- or GF-treated and recovered mice were reintoxicated with the original drugs but also colchicine and lumicolchicine. Cytoskeletal alterations of hepatocytes and MB formation were monitored by immunofluorescence microscopy using keratin, MB-specific antibodies, antibodies to phosphoepitopes and to HSP70. Keratin 8/18 mRNA expression and protein levels were determined by competitive reverse transcription-polymerase chain reaction, in situ-hybridization and western blotting. RESULTS: Duration of pretreatment was important for the efficiency of MB triggering. Rapid increase of keratin 8/18 mRNA and proteins was found in all reintoxicated mice concomitant with MB formation, whereby keratin 8 prevailed over keratin 18. Keratins and a protein with heat shock characteristics (M(M) 120-1 antigen) were the earliest detectable MB components, whereas ubiquitination and phosphorylation followed later. CONCLUSIONS: Overproduction of keratins is a major but not the only step responsible for MB formation. Additional components (e.g. M(M) 120-1 antigen) and excess of keratin 8 over keratin 18 are essential.

Animals↗
PubMed2001

Effects of ursodeoxycholic and cholic acid feeding on hepatocellular transporter expression in mouse liver.

BACKGROUND AND AIMS: Cholestasis is associated with retention of potentially toxic bile acids and alterations in hepatocellular transporter expression. Conversely, nontoxic ursodeoxycholic acid (UDCA) stimulates bile secretion and counteracts cholestasis. This study aimed to determine the effects of UDCA and cholic acid (CA) on the expression of hepatocellular transporters for bile acids (Ntcp, Bsep), organic anions (Oatp1, Mrp2), organic cations (Mdr1a/b), and phospholipids (Mdr2) in mouse liver. METHODS: Bile flow/composition was analyzed in UDCA- or CA-fed mice. Transporter expression was studied by reverse-transcription polymerase chain reaction, Western blotting, and immunofluorescence microscopy. RESULTS: UDCA had no effect on basolateral Ntcp and down-regulated Oatp1, whereas canalicular Bsep and Mrp2 were up-regulated. CA down-regulated basolateral Ntcp and Oatp1, whereas canalicular Bsep, Mrp2, and Mdr1a/b were up-regulated. Neither UDCA nor CA affected Mdr2 expression. Both UDCA and CA stimulated biliary bile acid and glutathione excretion, although only CA increased phospholipid and cholesterol excretion. CONCLUSIONS: Down-regulation of basolateral and up-regulation of canalicular transporters in response to CA may represent a defense mechanism, in an attempt to prevent hepatocellular accumulation of potentially toxic bile acids. The therapeutic effects of UDCA may be caused in part by stimulation of canalicular transporter expression in the absence of hepatocellular toxicity.

Administration, Oral↗
PubMed2001

Hepatobiliary transporter expression in percutaneous liver biopsies of patients with cholestatic liver diseases.

Reduced hepatobiliary transporter expression could explain impaired hepatic uptake and excretion of bile salts and other biliary constituents resulting in cholestasis and jaundice. Because little is known about alterations of hepatobiliary transport systems in human cholestatic liver diseases, it was the aim of this study to investigate such potential changes. Hepatic mRNA levels in hepatobiliary transport systems for bile salts (NTCP, BSEP), organic anions (OATP2, MRP2, MRP3), organic cations (MDR1), phospholipids (MDR3), and aminophospholipids (FIC1) were determined in 37 human liver biopsies and control livers by competitive reverse-transcription polymerase chain reaction (RT-PCR). Transporter tissue distribution was investigated by immunofluorescence microscopy. In patients with inflammation-induced icteric cholestasis (mainly cholestatic alcoholic hepatitis), mRNA levels of NTCP, OATP2, and BSEP were reduced by 41% (P <.001), 49% (P <.005), and 34% (P <.05) compared with controls, respectively. In addition, NTCP and BSEP immunostaining was reduced. MRP2 mRNA levels remained unchanged, but canalicular immunolabeling for MRP2 was also decreased. mRNA expression of MRP3, MDR1, MDR3, and FIC1 remained unchanged. In contrast to the alterations of transporter expression in inflammation-induced icteric cholestasis, transporter expression did not change in anicteric cholestasis caused by primary biliary cirrhosis (PBC) stages I and II. In conclusion, reduced expression of hepatobiliary transport systems for bile salts and other organic anions may contribute to inflammation-induced cholestasis in humans. Reduction of transporter gene expression can occur at the mRNA level as observed for NTCP, OATP2, and BSEP. However, reduced MRP2 immunostaining in the presence of conserved MRP2 mRNA levels suggests an additional role for posttranscriptional/posttranslational mechanisms.

ATP Binding Cassette Transporter, Subfamily B↗
PubMed2001

[Pathology and clinical medicine in the 21st Century].

The major task of pathology is to bridge the gap between basic science and clinical medicine. Consequently, pathology has to keep pace particularly with the progress in molecular biology and genetics and has to transfer the progress of basic research to studies of disease. Pathology has to test and continuously incorporate new methods into its scientific and diagnostic repertoire to improve diagnostic sensitivity and accuracy. The recognition of genetic alterations, particularly associated with tumors and chronic degenerative diseases, and its consequences in correlation with morphology allows the evaluation of changes in the genetic set-up and related cellular functions. This greatly improves the basis for understanding the biological background and clinical behavior of disease, thus adding a dynamic component to the snap-shot picture provided by the histologic slide. Application of genomics and proteomics will have significant impact on diagnostic pathology in the 21st century regarding definition and classification of pathologic processes, assessment of prognosis and guidance of treatment. The modern pathologist has to accept this challenge in order to maintain his position in the center of clinical medicine. However, despite all present and future advances, experience and skills in the morphologic evaluation of disease processes will still remain the "gold standard" in our field and the basis for proper application of these new technologies. When we accept the promising new techniques and tools already at the present early stage of development we may not only improve the clinical relevance of our work but gain invaluable information on the nature of diseases and the basic principles responsible for the complex morphologic pictures we enjoy in our daily work.

Clinical Medicine↗
PubMed2000

Long-term prognosis for colon cancer related to consistent radical surgery: multivariate analysis of clinical, surgical, and pathologic variables.

Despite the improvement in its prognosis in most Western countries, death from colon cancer is still a major problem. In a prospectively planned observation study, a large patient collective from a single institution in Austria was analyzed in terms of the surgical approach and factors influencing survival. A total of 696 patients with colonic carcinomas were admitted to our surgical department between January 1, 1984 and December 31, 1997. Radical surgery for localized tumors was consistently performed, including wide resection margins and complete removal of the regional lymph drainage zones. Clinical, histopathologic, and therapy-related factors were examined for their influence on long-term survival by means of univariate and multivariate analysis. The overall tumor resection rate was 99.3% (691/696); complete tumor removal (R0) was possible for 84.8% (590/696) of all patients. The overall postoperative hospital mortality rate was 3.2% (22/696), and it was 13% (7/556) for potentially curative resections. Five- and ten-year tumor-specific survival rates for stage I to III R0 resections were 83.8% and 78.8%, respectively. Adjuvant chemotherapy reduced tumor recurrence for stage III patients by 52.4%. The depth of tumor infiltration, lymph node status, and adjuvant chemotherapy were found to have an independent influence on survival as identified by the Cox models. In conclusion, a consistent radical surgical approach for potentially curative resected colonic cancer patients had survival rates that surpassed those of most published series without sacrificing low complication rates. In addition, adjuvant chemotherapy for stage III substantially improved survival.

Adult↗
PubMed2000

Lack of Pseudomelanosis coli in colonic adenomas suggests different pathways of apoptotic bodies in normal and neoplastic colonic mucosa.

Pseudomelanosis coli is characterized by pigment deposition in the lamina propria and caused by increased epithelial apoptosis. Pseudomelanosis coli is absent in colonic neoplasia. The aim of our studies was to investigate this phenomenon in more detail. Apoptotic fragments of epithelial cells and their distribution, cell proliferation (Ki-67, MIB 1 immunostaining), macrophages (CD68 immunostaining), Bcl-2 expression and apoptosis [terminal-deoxynucleotidyl-transferase mediated dUTP fluorescein nick end labeling (TUNEL) assay] were studied in adenomas arising in normal and melanotic colonic mucosa, in normal colonic mucosa and colonic mucosa with pseudomelanosis alone. In adenomas, we found 7.0 apoptotic bodies per 100 epithelial cells in the epithelial layer and only 0.2 apoptotic bodies per high power field (HPF) in the lamina propria. In contrast, in melanotic mucosa 1.7 apoptotic bodies per 100 epithelial cells in the epithelial layer and 2.5 per HPF in the lamina propria were found. Our results show that apoptotic fragments remain in the neoplastic (adenomatous) epithelium and do not reach (at least in higher amounts) the lamina propria. They can, therefore, not contribute to the development of pseudomelanosis in these lesions. However, macrophages are diminished in adenomas. Proliferation (Ki-67) and also Bcl-2 expression are highly increased in adenomas. The pathway of mucosal macrophages is also discussed.

Adenoma↗
PubMed2000

Hepatocyte cytokeratins are hyperphosphorylated at multiple sites in human alcoholic hepatitis and in a mallory body mouse model.

Alcoholic hepatitis (AH) is associated with cytokeratin 8 and 18 (CK8/18) accumulation as cytoplasmic inclusion bodies, termed Mallory bodies (MBs). Studies with MB mouse models and cultured hepatocytes suggested that CK8/18 hyperphosphorylation might be involved in MB formation. However, no data exist on phosphorylation of CK8/18 in human AH. In this study, antibodies that selectively recognize phosphorylated epitopes of CK8 or CK18 were used to analyze CK8/18 phosphorylation states in normal human and murine livers, human AH biopsies, and livers of 3,5-diethoxycarbonyl-1, 4-dihydrocollidine (DDC)-intoxicated mice, the last serving as model for MB induction. Hepatocyte cytokeratins become hyperphosphorylated at multiple sites in AH and in DDC-intoxicated mice. Hyperphosphorylation of CK8/18 occurred rapidly, after 1 day of DDC intoxication and preceded architectural changes of the cytoskeleton. In long-term DDC-intoxicated mice as well as in human AH, MBs preferentially contain hyperphosphorylated CK8/18 as compared with the cytoplasmic cytokeratin intermediate filament network suggesting that CK8/18 hyperphosphorylation may play a contributing role in MB pathogenesis. Furthermore, the site-specific phosphorylation of cytokeratin in different stages of MB induction provides indirect evidence for the involvement of a variety of protein kinases known to be activated in stress responses, mitosis, and apoptosis.

Animals↗
PubMed2000

Cytokeratin 8 protects from hepatotoxicity, and its ratio to cytokeratin 18 determines the ability of hepatocytes to form Mallory bodies.

In alcoholic hepatitis, a severe form of alcohol-induced toxic liver injury, as well as in experimental intoxication of mice with the porphyrinogenic drugs griseofulvin and 3,5-diethoxycarbonyl-1, 4-dihydrocollidine, hepatocytes form cytoplasmic protein aggregates (Mallory bodies; MBs) containing cytokeratins (CKs) and non-CK components. Here we report that mice lacking the CK8 gene and hence CK intermediate filaments in hepatocytes, but still expressing the type I partner, ie, the CK18 gene, do not form MBs but suffer from extensive porphyria and progressive toxic liver damage, leading to the death of a considerable number of animals (7 of 12 during 12 weeks of intoxication). Our observations show that 1) in the absence of CK8 as well as in the situation of a relative excess of CK18 over CK8 no MBs are formed; 2) the loss of CK8 is not compensated by other type II CKs; and 3) porphyria and toxic liver damage are drastically enhanced in the absence of CK8. Our results point to a protective role of CKs in certain types of toxic liver injury and suggest that MBs by themselves are not harmful to hepatocytes but may be considered as a product of a novel defense mechanism in hepatocytes.

Animals↗