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Biomedical subjects

G Klein

Publications and source records attributed to G Klein.

At least 217 records · Page 12Linked to original sources
PubMed1996

Genotypic and phenotypic characterization of two newly established renal cell carcinoma cell lines.

Two new cell lines from human renal cell carcinoma are reported. Primary cell cultures from 75 consecutive cases of nephrectomy and metastatic surgery due to different stages of RCC during 4 years were studied. Two cell cultures could be propagated for more than 50 passages in vitro. HN4 was derived from a grade III clear cell carcinoma. HN51 originated from a metastatic brain lesion of a clear cell carcinoma grade III. Karyotype analysis of HN4 revealed triploidy with a clonal aberration, der(10)t(3;10)(q13;p12). HN51 also had a triploid pattern with different marker chromosomes but without any clonal aberration. Loss of heterozygosity studies revealed no loss of heterozygosity on 3p or other chromosomal markers in HN4 but LOH was found on one 3p marker and one 14q marker in addition to all 17 p and q markers in HN51. In vitro light microscopy showed distinctly different morphology in the two cell lines although they both had a typical epithelial growth pattern. Doubling times in vitro were low but slightly higher for HN51. Repeated tumorigenenic experiments in athymic mice only gave rise to subcutaneous tumors with HN51. On characterization by 2-dimensional gel electrophoresis, the two cell lines exhibited different polypeptide patterns with higher expression of proliferating cell nuclear antigen in HN51 and higher expression of glutathione-S-transferase in HN4 constituting the most prominent differences.

Aged↗
PubMed1996

Expression of laminin alpha 1, alpha 5 and beta 2 chains during embryogenesis of the kidney and vasculature.

Laminins, found predominantly in basement membranes, are large glycoproteins consisting of different subsets of alpha, beta and gamma chain subunits. To resolve conflicting data in the literature concerning coexpression of alpha 1 and beta 2 chains, expression of alpha 1 chain was studied with two different antisera against the E3 fragment of laminin alpha 1 chain. Expression of the alpha 1 chain was seen in several types of epithelial basement membranes throughout development, but its expression in rat glomerular basement membranes and some other types of epithelial basement membranes occurred only during early stages of development. By contrast, beta 2 chains were detected by immunofluorescence only during advanced stages of glomerulogenesis and vascular development. By Northern and Western blots, beta 2 chains were detected somewhat earlier, but in situ hybridization revealed that beta 2 chain was also confined to vasculature during the earlier stages. It thus seems that, in the tissues studied here, the expression of alpha 1 and beta 2 chains was mutually exclusive. To explore whether the newly described alpha 5 chain is expressed in locations lacking alpha 1 chain, expression of alpha 5 chain was studied by Northern blots and in situ hybridization. The alpha 5 chain was not uniformly expressed in all embryonic epithelial cell types but was present mainly in epithelial sheets which produce very little alpha 1 chain. There also appeared to be a developmental trend, with alpha 1 chain appearing early and alpha 5 later, in maturing epithelial sheets. The alpha 5 chain could be a major alpha chain of the adult glomerular basement membrane.

Aging↗
PubMed1996

Follow-up of atrial fibrillation: The initial experience of the Canadian Registry of Atrial Fibrillation.

Previous reports of the follow-up of patients with atrial fibrillation have been confusing because of the variety of clinical presentations, heterogeneity of underlying pathology, and the initiation of follow-up at various stages of the patient's disease. The Canadian Registry of Atrial Fibrillation (CARAF) is a non-interventional, follow-up study of patients enrolled at the time of their initial diagnosis with atrial fibrillation at seven Canadian centres. At baseline, a comprehensive database recorded clinical, laboratory, and echocardiographic variables. No specific intervention was initiated and care was left to the attending physicians. Follow-up was performed at 3 months, 1 year, then annually. Echocardiograms were repeated every 2 years. Recurrence of atrial fibrillation, medical intervention, stroke, death, and other significant events have been specifically recorded. To date, 967 patients have been enrolled. Seven hundred and sixty-seven patients have been followed for 1 year, 468 for 2 years, and 217 for 3 years. Several studies have been undertaken on these patients. One study compared the variables of patients who were symptomatic with those who were asymptomatic. This study demonstrated that symptoms were more likely to occur if the patient were younger, had high blood pressure and high ventricular response during atrial fibrillation, and were female. These all achieve statistical significance and a formula was developed to predict the probability of symptoms in different subgroups of patients. Antiarrhythmic drug use was evaluated. Sotalol and propafenone were the most commonly used drugs and their use increased when atrial fibrillation was recurrent. Many patients initially received no antiarrhythmic drugs. Trends suggest that therapy is more aggressive with recurrence of the arrhythmia. The prevalence of thyroid abnormalities was investigated utilizing sensitive TSH measurements. This showed that overt hyperthyroidism is rare (1%) but laboratory abnormalities and history of thyroid dysfunction occurred more frequently, in 19% of patients. Another study evaluated antithrombotic therapy. Factors known to increase stroke risk, including congestive heart failure, previous stroke, and large left atrium all increased the use of anticoagulants. Anticoagulants were used more frequently in patients over the age of 65 and in patients with recurrent or chronic atrial fibrillation. There was concern that hypertension, shown to be a high predictor of stroke, did not result in a significant use of warfarin. Aspirin use was common in patients not placed on anticoagulants. Further studies are being undertaken with the ultimate goal to utilize baseline data to predict clinical outcomes.

Anti-Arrhythmia Agents↗
PubMed1996

Homozygous and compound heterozygous mutations at the Werner syndrome locus.

The Werner syndrome (WS) is a rare autosomal recessive progeroid disorder. The Werner syndrome gene (WRN) has recently been identified as a member of the helicase family. Four distinct mutations were previously reported in three Japanese and one Syrian WS pedigrees. The latter mutation was originally described as a 4 bp deletion spanning a spliced junction. It is now shown that this mutation results in a 4 bp deletion at the beginning of an exon. Nine new WRN mutations in 10 additional WS patients, both Japanese and Caucasian, are described. These include three compound heterozygotes (one Japanese and two Caucasian). The new mutations are located all across the coding region.

Asian People↗
PubMed1996

Lactobacillus curvatus subsp. curvatus subsp. nov. and Lactobacillus curvatus subsp. melibiosus subsp. nov. and Lactobacillus sake subsp. sake subsp. nov. and Lactobacillus sake subsp. carnosus subsp. nov., new subspecies of Lactobacillus curvatus Abo-Elnaga and Kandler 1965 and Lactobacillus sake Katagiri, Kitahara, and Fukami 1934 (Klein et al. 1996, emended descriptions), respectively.

Lactobacillus curvatus and Lactobacillus sake are each genetically homogeneous species, as indicated by the high levels of DNA homology (> or = 76%) exhibited by strains of these taxa. However, the results of a numerical analysis of total soluble cell protein patterns and biochemical test data revealed that there are two phenotypic subgroups within L, curvatus and two phenotypic subgroups within L. sake. The overall randomly amplified polymorphic DNA (RAPD)-PCR band patterns obtained for the majority of L. curvatus strains corresponded well to the pattern obtained for the type strain of L. curvatus (strain DSM 20019). However, six strains of L. curvatus had different, but similar, RAPD-PCR profiles and grouped in a separate genetic cluster, which was linked to one of the clusters of L. sake strains. On the basis of these results, differences in biochemical and physiological characteristics, and total soluble cell protein profiles, we describe the subspecies L. curvatus subsp. curvatus subsp. nov. and L. curvatus subsp. melibiosus subsp. nov. for L. curvatus Abo-Elnaga and Kandler 1965 (Klein et al. 1996, emended description). Strains of L. sake grouped in two RAPD-PCR clusters, which was consistent with previous reports of phenotypic heterogeneity. Strains of Lactobacillus bavaricus, including type strain LMG 9844, clustered with the type strain of L. sake (strain NCFB 2714), indicating that these organisms belong to the same genetic group. We propose that strains of L. sake Katagiri, Kitahara, and Fukami 1934 (Klein et al. 1996, emended description) should be reclassified as members of L. sake subsp. sake subsp. nov. and L. sake subsp. carnosus subsp. nov. Strains of L. bavaricus are reclassified as members of L. sake subsp. sake, and the name L. bavaricus Stetter and Stetter 1980 is rejected.

DNA, Bacterial↗
PubMed1996

B cell-specific activation of the Epstein-Barr virus-encoded C promoter compared with the wide-range activation of the W promoter.

We have studied the activity of reporter plasmids, carrying the Epstein-Barr virus (EBV) nuclear antigen (EBNA) promoters Wp and Cp, in a group of somatic cell hybrids obtained by fusing EBV-positive lymphoblastoid cell lines or group II/III Burkitt's lymphoma cell lines with non-B cell lines. In B/non-B cell hybrids of this type, B cell markers are extinguished as a rule, in parallel with the inactivation of Cp or Wp and down-regulation of EBNA-2-6 expression. A Wp-carrying reporter construct was active in non-B cell lines. Only cells with a B cell phenotype could support the activity of Cp-carrying plasmids. EBNA-2 transactivated Cp only in B cells. Our data suggest that while Wp can be used for EBNA transcription in B and non-B cells, Cp activity is restricted to B cells. The inability of EBNA-2 to transactivate Cp in non-B cells indicates that other factors present in B cells might be involved in Cp transactivation.

Antigens, Viral↗
PubMed1996

The Epstein-Barr virus-encoded nuclear antigen EBNA-5 accumulates in PML-containing bodies.

EBNA-5 is one of the Epstein-Barr virus (EBV)-encoded nuclear proteins required for immortalization of human B lymphocytes. In the nuclei of EBV-transformed lymphoblastoid cell lines EBNA-5 is preferentially targetted to distinct nuclear foci. Previously we have shown (W.Q. Jiang, L. Szekely, V. Wendel-Hansen, N. Ringertz, G. Klein, and A. Rosen, Exp. Cell Res. 197:314-318, 1991) that the same foci also contained the retinoblastoma (Rb) protein. Using a similar double immunofluorescence technique, we now show that these foci colocalize with nuclear bodies positive for PML, the promyelocytic leukemia-associated protein. Artificial spreading of the chromatin by exposure to the forces of fluid surface tension disrupts this colocalization gradually, suggesting that the bodies consist of at least two subcomponents. Heat shock or metabolic stress induced by high cell density leads to the release of EBNA-5 from the PML-positive nuclear bodies and induces it to translocate to the nucleoli. In addition to their presence in nuclear bodies, both proteins are occasionally present in nuclear aggregates and doughnut-like structures in which PML is concentrated in an outer shell. Nuclear bodies with prominent PML staining are seen in resting B lymphocytes. This staining pattern does not change upon EBV infection. In freshly infected cells EBNA-5 antigens are first distributed throughout the nucleoplasm. After a few days intensely staining foci develop. These foci coincide with PML-positive nuclear bodies. At a later stage and in established lymphoblastoid cell lines EBNA-5 is almost exclusively present in the PML-positive nuclear foci. The colocalization is restricted to EBV-infected human lymphoblasts. The data presented indicate that the distinct EBNA-5 foci are not newly formed structures but the result of translocation of the viral protein to a specialized domain present already in the nuclei of uninfected cells.

Antigens, Viral↗
PubMed1996

The adhesion molecule E-cadherin and a surface antigen recognized by the antibody 9C4 are selectively expressed on erythroid cells of defined maturational stages.

The antigen expression of immature erythroid bone marrow cells was studied using two recently generated monoclonal antibodies (mAb), mAb 67A4 and 9C4, with specificities for the epithelial cell adhesion molecule E-cadherin (E-cad; mAb 67A4), and a novel 110 kDa differentiation antigen (mAb 9C4) with unknown molecular structure. Pappenheim staining of FACS-purified cells labeled with mAb 9C4 and anti-glycophorin A (GA) revealed that the majority of the 9C4+GA- and 9C4+GA+ cells consisted of erythroblasts. In contrast, the E-cad-positive population comprised normoblasts and erythroblasts. While the E-cad+GA- fraction contained mainly erythroblasts and basophilic normoblasts, the E-Cad+GA+ population was enriched in orthochromatic and polychromatophilic normoblasts. By colony assays of affinity column-purified cells it could be shown that erythroid colony forming units (CFU-E) were enriched and erythroid burst forming units (BFU-E) were depleted in the 9C4- and E-cad-positive fractions. Flow cytometric analysis of bone marrow cells double-labeled with mAb 67A4 and anti-CD71, anti-CD117, anti-CD34, or anti-GA revealed that about 90% of the E-cad-positive cells coexpressed CD71, about 70% were positive for CD117, about 50% for GA, and only about 5% coexpressed CD34. The expression pattern of 9C4 antigen was similar to that of E-Cad with the exception that only a minority of the 9C4-positive cells coexpressed GA. Lymphoid and myeloid markers were negative on both the E-Cad- and 9C4-positive populations. In these studies we describe the identification of a new mAb-defined antigen which is specifically expressed on erythroblasts and CFU-E(9C4) and demonstrate that E-Cad is not only expressed on epithelial cells but also on erythropoietic cells of defined maturational stages.

Antibodies, Monoclonal↗
PubMed1996

EBV-B cell interactions: immortalization, rescue from apoptosis, tumorigenicity (a short review).

Translocation of the c-myc gene to an immunoglobulin locus is a rate-limiting step in the genesis of three B-cell derived tumors: Burkitt lymphoma (BL) in humans, mouse plasmacytoma (MPC) and rat immunocytoma. Its consequences have been best analyzed in BL. They involve a non-immunological and an immunological component. The former acts by preventing the B cell from leaving the cycling compartment and entering the resting stage when programmed to do so. The latter acts by the down regulation of certain HLA class I polymorphic specificities, adhesion molecules and EBV encoded proteins. According to our interpretation, the translocation fixes the BL cell in a phenotypic window that can be referred to as "a resting cell that is not resting". The linking of c-myc to immunoglobulin sequences in a B cell leads to constitutive myc expression. In spite of its switch to a "resting phenotype", the cell is therefore unable to leave the cycling compartment. Normally, EBV-carrying B-blasts face immune controls. They can only proliferate in immunodefectives, as in XLP or transplant lymphoma. Due to its "resting" rather than B-blast phenotype and the correlated defective expression of certain EBV, HLA and adhesion molecules, the BL cell is not rejected by the EBV-specific immune response, however. The down-regulation of EBNA 2-6 in the BL cell may be also considered in relation to viral latency. The exclusive expression of EBNA 1 in the BL cell reflects the adaptation of the virus to prolonged persistence in long lived resting B cells, an important if not exclusive reservoir of the latent virus. Normal B cells that fail to be activated by appropriate mitogens or antigens within a limited period of time undergo apoptosis, as a rule. EBV may protect resting B cells. The role of the only virally encoded protein they are known to express, EBNA 1, remains to be explored in this respect. EBV infected immunoblasts are protected from apoptosis by the LMP 1 induced elevation of bcl-2 expression. During the lytic cycle when cellular protein synthesis is switched off by the early viral proteins, a member of the early protein group, a bcl-2 homologous protein encoded by the BHRF1 gene, takes over the function to protect against untimely apoptosis.

Alternative Splicing↗
PubMed1996

NotI jumping and linking clones as a tool for genome mapping and analysis of chromosome rearrangements in different tumors.

Long-range restriction site maps are of central importance for mapping the human genome. The use of clones from linking and jumping libraries for genome mapping offers a promising alternative to the laborious procedures used up until now. In the present review, this research field is analyzed with particular emphasis on the implementation of a shot-gun sequencing strategy for genome mapping and the use of NotI linking clones for analysis of rearrangements in tumors and tumor cell lines.

Base Sequence↗
PubMed1996

Phenotype-related differences in the expression of D-type cyclins in human B cell-derived lines.

Exposure of normal resting B lymphocytes to EBV in vitro leads to activation, subsequent immortalization, and the establishment of lymphoblastoid cell lines (LCLs). The endemic form of Burkitt's lymphoma (BL) is associated with EBV. EBV-positive BL lines maintain the original tumor phenotype (group I BL) initially and express only one EBV-encoded protein, EBV nuclear antigen (EBNA)-1. Most of them drift toward a LCL-like phenotype during in vitro culturing and express all nine EBV-encoded growth transformation-associated proteins (group III BL). Cyclin D2 and D3 have been found previously to differ in their mRNA expression in BL and LCL. Cyclin D2 expression has been attributed to EBV gene expression and to EBNA-2 and EBNA-5 in particular. We have studied cyclin D2/D3 expression in larger series of LCLs, BL lines, and freshly EBV-infected peripheral blood B lymphocytes, both at the mRNA and protein levels. The predominant cyclin D2 expression in the LCLs and group III BLs correlated with an activated B-cell phenotype. In contrast, only cyclin D3 was expressed in the group I BL lines. EBV-carrying group II BL lines that retained the BL-associated CD10 did not express cyclin D2. A collection of in vitro EBV-converted sublines of originally EBV-negative BLs that expressed a full set of the growth transformation-associated EBV proteins maintained their CD10 and cyclin D3 expression. Blood B lymphocytes expressed no D2 or D3 as judged by immunostaining. Cyclin D2 could be detected by immunostaining in a proportion of the activated blasts 40 h postinfection. Cyclin D3 that is expressed at a low level in the established LCLs was stained easily in B blasts at this time. The level of cyclin D3 at 72 h postinfection was two to three times higher than in the exponentially growing LCLs, as detected by immunoblotting. It was still 5-10 times lower than in group I BLs. Mitogen stimulation of primary B cells induced cyclin D3 at a similar level as in the LCLs. Our data are consistent with the notion of cell lineage-specific D-type cyclin expression. They also indicate that B cells may switch their D-type cyclin expression during differentiation.

B-Lymphocytes↗
PubMed1996

[Possible effect of hormones on immune and inflammatory processes in female patients with chronic polyarthritis].

The influence of gender on the prevalence of rheumatoid arthritis (RA) is well known. We examined 40 female patients with RA to show the possible influence of androgen hormones on inflammation and immune system. We measured blood count, blood sedimentation rate, C-reactive protein routinely and free and bound testosterone, dehydroepiandrosterone-sulfate (DHEA-S), prolactin, insulin like growth factor-1 (IGF), IgA-rheumatoid factor (IgA-RF) and the monocyte marker CD 14 of radioimmunoassays and enzymeimmunoassays. The female patients with RA had lower androgen levels correlating with higher inflammatory markers which are not rising significantly with higher age. The significantly raised IgA-RF with abnormal low testosterone levels points out a poor prognosis for developing joint erosions. The simultaneously reduced levels of prolactin may be rather caused by cytokines and could have additional connections to the anemia in RA. Somatomedin correlated inversely to the degree of inflammation, measured by BSR, CRP and CD 14, a fact which could indicate a reduced, Somatomedin-induced, synthesis in matrix and collagen of cartilage in "active" RA. The results point to the existence of a reciprocal connection of the endocrine system with the immune system.

Adult↗
PubMed1996

[Gastroduodenal tolerance and clinical effectiveness of therapy with lonazolac-calcium in rheumatic diseases].

Most undesired side effects in therapy with non-steroidal antiinflammatory drugs (NSAID) mainly effect the gastric and duodenal mucosa. The radioimmunological determination of pepsinogen A and C (pepsinogen group I and II) is qualified for inclusion of the functional and morphologic state of the gastroduodenal mucosa. By determination of the pepsinogens group A and C the influence and the gastroduodenal compatibility of the non-steroidal antiinflammatory drug lonazolac Ca (LCa) [Irritren] were examined in a dosage of 600 mg/d during a 2-weeks therapy. 31 patients with various painful rheumatic diseases and 10 healthy probands as a control group were examined. The results show that the treatment with LCa did not significantly effect mean and median of pepsinogen A- and -C levels in serum. Only in 3.7% of the cases a contemporary increase of pepsinogen A and C occurred, which could be estimated as a beginning superficial gastritis. In addition the beneficial clinical efficacy of LCa was documented by a significant decrease of a tripartite pain score from 2.1 to 1.4. The results point to a very good proportion of clinical efficacy and gastroduodenal side-effects of LCa.

Adult↗