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Biomedical subjects

H Lobeck

Publications and source records attributed to H Lobeck.

At least 109 records · Page 6Linked to original sources
PubMed1989

Relation between Escherichia coli R(rough)-forms in gut, lipid A in liver, and primary biliary cirrhosis.

Since antimitochondrial antibodies (AMA) specific to primary biliary cirrhosis (PBC) recognise enterobacterial proteins and can be induced by R(rough)-mutants of enterobacteriaceae a study was done to find out the prevalence of enterobacterial R-forms in stool samples of patients with chronic inflammatory liver diseases. Liver biopsy specimens were also examined for lipid A, a common antigenic component of the cell wall in gram-negative bacteria. In all stool samples from the 21 patients with PBC Escherichia coli R-forms constituted up to half of the total amount of E coli. In contrast E coli R-forms were detectable in the stools of only 1 healthy control (n = 20), and in 25% of patients with other cholestatic diseases (n = 10), chronic hepatitis type B (n = 15), type non-A, non-B hepatitis (n = 15), or chronic pancreatitis and fat malabsorption (n = 8). An immunoblot technique showed that E coli R-forms isolated from patients' stools contained PBC-specific AMA-reactive proteins with molecular weights of 70-80 kD and 50 kD. Deposits of lipid A, located primarily in the cytoplasm of hepatocytes, were found in 11 patients with PBC but not in the liver of patients with chronic viral hepatitis. Circulating antibodies against lipid A were found rarely and in low titres. The data support the hypothesis that intestinal enterobacterial R-forms are aetiologically important in PBC and that antigens released from the bacterial cell wall contribute to the pathogenesis of the disease.

Adult↗
PubMed1989

Lysine-specific cleavage of beta 2-microglobulin in amyloid deposits associated with hemodialysis.

Amyloid fibrils isolated from bone and carpal synovia of seven patients on long-term hemodialysis were further characterized biochemically. In addition, renal amyloid stones of three dialyzed patients were examined. All deposits and stones were of beta 2-microglobulin-origin (AB-amyloid) by immunohistochemical and immunochemical evaluation. Amyloid fibril extracts were dissolved in 80% formic acid and separated by high performance liquid chromatography in 60% formic acid and 20% 2-propanol. Three major retarded fractions with molecular weights of approximately 24, 12 and 7 to 10 kD were recovered. N-terminal amino acid sequence analysis documented beta 2-microglobulin (beta 2m) as the principal polypeptide in all investigated cases. In addition to proteins with intact N-termini, one fragment commencing with isoleucine in position 7 was found in osseous or synovial amyloid. In renal amyloid stones, one additional fragment was found beginning with serine in position 20. Generally, these data point to proteolytic cleavage carboxyterminal to a lysine residue and establish that not only intact beta 2m but also at least one beta 2m fragment is present in beta 2m-derived amyloid deposits of patients with long-term hemodialysis. The fragmentation pattern is consistent with the action of lysine-specific protease(s) and underscores a potentially important role of limited proteolysis in the pathogenesis of AB-amyloid deposits.

Adult↗
PubMed1989

[Imaging diagnosis of aggressive fibromatosis and the MRT-pathological correlation].

Aggressive fibromatoses (desmoid tumours) tend to grow in an infiltrative and destructive manner without metastases. Computed tomography of aggressive fibromatoses yields no uniform attenuation pattern. The tumours are typically isodense when no contrast medium is used and enhance clearly to hyperdense during infusion of contrast medium. In magnetic resonance tomography (MRT) a high signal (long T2) on T2-weighted pulse sequences as well as an accumulation of i.v. Gd-DTPA seems to be the characteristic appearance of aggressive fibromatoses, although different signal intensities can be seen. The MRT histopathologic correlation shows increasing signal intensities on T2-weighted sequences dependent on an increment in cellular content of the tumours. Only histopathological methods can provide a definite diagnosis.

Adolescent↗
PubMed1989

[Congenital ependymoma. Case report and immunohistochemical studies].

Reported in this paper is a congenital ependymoma in an 23-week old foetus. The neoplasm was well vascularised and contained typical ependymal rosettes. The tumour cells did not react with GFAP-antiserum. They reacted weakly with neuron-specific enolase and vimentin and exhibited strong antigenicity with S-100-protein-antiserum. Cytokeratin antigen was recordable from some tumour cells. The tumour was sufficiently mature for classification as ependymoma. Immunohistochemical findings suggested possible ectodermal origin of the tumour cells.

Brain Neoplasms↗
PubMed1989

[Hepatitis B in established cardiac cirrhosis--a rare indication for liver transplantation].

A 34 year old patient was diagnosed as suffering from congestive cirrhosis due to constrictive pericarditis 18 years ago. A terminal dystrophic episode of additionally acquired chronic aggressive hepatitis B led to rapidly progressive liver failure. Orthotopic liver transplantation was carried out. 10 months after transplantation the patient is alive and well. Presence of HBsAg and HBcAg can again be demonstrated in the liver graft, however, without histologic evidence of hepatitis. Problems of prognosis after liver transplantation for hepatitis B virus infection are discussed.

Adult↗
PubMed1988

The value of immunocytochemical staining of lymph node aspirates in diagnostic cytology.

This study investigates the applicability of immunocytochemical techniques towards improving the cytological diagnosis of lymph node disorders. Cytocentrifuge preparations of fine needle aspirates were examined using an indirect immunoperoxidase method and the alkaline phosphatase-antialkaline phosphatase method. 36 reactive lymph nodes were evaluated. 23 patients showed T cell predominance as assessed by the presence of CD3+ cells. 13 patients showed an excess of CD24+ cells over CD3+ cells. In all patients the B cell population showed no light chain class restriction. 48 aspirates from patients with B-non-Hodgkin's lymphoma of low malignancy were investigated. The majority of the cells in each of these cases expressed CD24 and 47 cases were monoclonal with respect to their light chain determinants. In 37/48 cases the antibody OKT9 reacted with less than 15% of cells. 18 aspirates were obtained from patients with B-non-Hodgkin's lymphoma of high malignancy. 17 patients showed light chain class restriction and a high percentage of CD24+ (greater than 80%) and OKT9+ (greater than 40%) cells. 8 malignancies were considered to be of T-cell origin. A low percentage (less than 15%) of Ig+CD24+ cells with a high number of CD3+ and/or CD4+ cells suggests a T-cell lymphoma. The majority of neoplastic cells in peripheral T-cell lymphomas (excluding mycosis fungoides) expressed OKT9 and CD3 expression was found to be variable. In 15 cases of Hodgkin's disease, there were 11 correct cytologic diagnoses. A significant number of BerH2 (CD30)+ cells having the morphology of Sternberg-Reed cells supports this diagnosis. 25 aspirates were obtained from patients with metastatic malignant tumours. Marker studies in eight cases helped in distinguishing metastatic malignant tumours from malignant lymphomas. Our findings indicate that the immunocytochemical technique is applicable to cytological material and that the simplicity of the procedure merits application to routine diagnostic cytology.

Antibodies, Monoclonal↗
PubMed1988

The significance of high-density lipoproteins (HDL) in the clearance of intravenously administered bacterial lipopolysaccharides (LPS) in mice.

The direct immunofluorescence technique was used to study the presence of high-density lipoproteins (HDL) in the liver, spleen and kidney of mice before and after intravenous administration of purified lipopolysaccharides (LPS) from Escherichia coli O 75, Salmonella abortus equi and Salmonella minnesota R 595, as well as free lipid A. Untreated mice had small granules of HDL in the hepatocellular cytoplasm, which appeared more pronounced after oral administration of fat. After intravenous administration of LPS, hepatocellular HDL decreased continuously and was no longer visible 1 hour after injection of LPS or lipid A. Five to ten minutes after administration, smooth-form LPS were located in sinusoidal cells, and rough form LPS and lipid A were found in both parenchymal and nonparenchymal liver cells. All toxins were demonstrated in both cell populations 1-4 hours after injection. The spleen was free of HDL, while there was a strong uptake of LPS into the cells of the reticulo-endothelial system. The kidney of experimental mice had small HDL granules in the epithelial cells of the proximal tubules, with a tendency to move to the lumen 1 hour after LPS injection, while there was a transient granular deposition of LPS in the glomeruli. The results suggest that the early uptake of circulating LPS by cells of the reticulo-histiocytic system in liver and spleen, as well as by hepatocytes, is not mediated by HDL. However, HDL located in hepatocytes or present in the circulation of experimental mice seem to be eliminated through the bile and the urine, induced by LPS.

Animals↗
PubMed1988

[Frequency and clinical relevance of delta virus infection in HBsAg carriers in the Berlin area].

The frequency of delta virus infection, immunoserological parameters and degree of liver inflammation were studied in 190 HBsAg carriers in the Berlin area from 1976 to 1986. Delta infection was detected in one of 50 HBsAg carriers (2%) in the period from 1976 to 1980. In contrast 19 of 140 HBsAg carriers (14%) with delta infection were found in the period from 1981 to 1986. This group included 12 Germans, 5 Turks and 2 Italians. Only 6 of these subjects belonged to a so-called risk group: 3 drug addicts, 2 homosexuals and 1 hemophiliac. Eighteen of the 20 patients with HDV infection showed progressive liver disease in the follow-up period. Nine cases developed complete liver cirrhosis over five years. Variable transaminase levels and elevation of immunoglobulin G were recorded. Humoral autoimmune phenomena were rarely observed. The increasing frequency of HDV infection in the Berlin area is presumably related to tourism, national origin and membership in specific risk groups. The data in our study underline the importance of effective prophylaxis by active immunization with HBsAg vaccines.

Adult↗
PubMed1988

[Schoenlein-Henoch purpura in chronic HBsAG-positive hepatitis].

We report about a 40-year-old male patient suffering from a recurrent vasculitis with purpura since the age of 18. In 1983, a HBsAg-positive chronic active hepatitis with circulating immune complexes which contained HBsAg, immunoglobulin M and G as well as complement (C) was diagnosed. Serum and liver tissue were negative for HBcAg, HBeAg and hepatitis B virus (HBV) DNA; there was no evidence for HBV replication. HBsAg, IgM and C3 were demonstrable in the arteriolar walls of the skin. The results support the concept that complement activating immune complexes containing HBsAg and IgM anti HBs play a role in the pathogenesis of vasculitis as described here.

Adult↗
PubMed1987

[Keratin expression in normal and malignant transformed squamous epithelium of the digestive mucosa of the head].

Keratins are alpha-type fibrous polypeptides which basically compose 10 nm thick or intermediate-sized filaments (IF) in almost all epithelial cells and tissues. Their patterns of expression in normal and malignant upper digestive tract squamous epithelium were monitored by high resolution gel electrophoresis, immunoblotting, and immunohistochemical techniques. Uninvolved epithelia, in all instances, were found to express keratins 4, 5, 6 and 13, 14 the members of the high molecular weight basic (type II or Type B) and of the low molecular weight acidic (type I or type A) subfraction, respectively. Cancers of squamous epithelial cell origin retain keratin synthesis. However, their overall patterns of keratin expression appeared aberrant when compared with those of normal epithelia. In particular, these differences result from highly proliferative tumour cells unable in most cases to synthesize keratins 4/13, a type II/type I keratin pair which specifically indicates in squamous primarily non-keratinizing epithelia completely, i.e. terminally differentiated (suprabasal or spinous) cells. The patchwise expression of acidic keratin 13 in related primaries confirms their heterogeneous phenotype, and may be explained, in part, by cancer cells no longer resistant to terminal differentiation as a result perhaps of an altered micro-environment and/or in response to various effects mediated by vitamin A. We discuss some problems pertinent to the biochemical analysis of keratin polypeptides in normal and involved epithelial tissues, and relate to the controversial question whether specific keratin members may actually candidate for markers of malignancy.

Carcinoma, Squamous Cell↗
PubMed1986

Malignant fibrous histiocytoma associated with peripheral blood eosinophilia. In vitro studies demonstrating tumor-derived eosinophilopoietic activity.

Peripheral blood eosinophilia is a well-recognized paraneoplasia in many kinds of hematological and nonhematological malignancies. We report the case of a patient with a malignant fibrous histiocytoma. With increasing tumor burden, the patient developed a marked peripheral blood eosinophilia. Using an in vitro assay for growth of eosinophilic colonies, both the serum and the tumor of the patient proved to contain an eosinophilopoietic activity.

Cell Division↗
PubMed1985

[Immunoserologic differentiation of chronic cholestatic hepatitis. Significance of antimitochondrial antibodies and hepatic membrane antibodies].

In 22 of 45 patients with chronic cholestatic liver inflammation and humoral immune phenomena, followed over 15 years with at least one liver biopsy, there was the histological picture of primary biliary cirrhosis (PBC), stages I to IV, with constantly demonstrable antimitochondrial antibodies (AMA) of M2-type. In 12 patients there were signs of PBC and chronic active hepatitis (CAH) in the liver histology, and they were M2-positive. Six of them also had M4-antibodies and were thus classified as 'mixed form'. The other six were seropositive for liver-membrane antibodies (LMA) and (or) antinuclear antibodies (ANA) and thus demonstrated an overlap between PBC and autoimmune or lupoid CAH. In five patients there was autoimmune CAH of lupoid type, in four of them with LMA or ANA without M2- or M4-antibodies. The remaining six patients had pericholangitis with persisting ANA and increased serum concentrations of immunoglobulin M without M2- and M4-antibodies, as well as LMA. Clinically a nondestructive polyarthritis predominated without definite signs of collagenosis. The listed immunoserological parameters make it largely possible to differentiate classical PBC, mixed forms or overlap of PBC and CAH, autoimmune CAH and nonpurulent cholangitis of pericholangitic type.

Aged↗
PubMed1985

[Serologic analysis of HBc antigen in patients with HBs-antigen carrier state].

Treatment of serum with sodium thiocyanate in HBs antigen carrier patients leads to liberation of circulating HBc antigen which can be demonstrated radioimmunologically. Investigations were done in 54 HBs antigen carriers, 44 of whom had chronic inflammatory liver disease (22 patients each HBe antigen positive and negative), and in 10 patients who were asymptomatic (so-called healthy HBs antigen carriers). Out of the 22 HBe antigen positive patients 17 were HBc antigen positive serologically. In the HBe antigen negative group of HBs antigen carriers two out of 22 patients with HBc antigen in serum were detected. All 10 asymptomatic HBs antigen carriers were HBc antigen negative. In 11 out of the 40 immunohistologically assessed patients HBc antigen could be demonstrated in hepatocellular nuclei; these 11 patients also demonstrated HBc antigen in serum. The liberated HBc antigen was associated with Dane particles in the density gradient. Serologic demonstration of HBc antigen may thus be considered as direct evidence of presence of hepatitis B virus.

Carrier State↗