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H Huber

Publications and source records attributed to H Huber.

At least 19 recordsLinked to original sources
PubMed1992

Subpopulations of normal peripheral blood and bone marrow cells express a functional multidrug resistant phenotype.

The multidrug-resistance gene, MDR1 is expressed in many normal tissues, but little is known about its expression in normal hematopoietic cells. Using the monoclonal antibody C219 and flow cytometric analysis, P-glycoprotein (P-gp) was found to be expressed in all peripheral blood (PB) subpopulations (CD4, CD8, CD14, CD19, CD56) except granulocytes. To specifically determine MDR1 gene expression, these PB subpopulations were isolated by fluorescence-activated cell sorting (FACS) and analyzed for MDR1 mRNA by polymerase chain reaction (PCR). All subsets were positive by PCR, but only minimal MDR1 mRNA was detected in monocytes and granulocytes. Significant efflux of Rhodamine-123 (Rh-123), a measure of P-gp function, was detected in CD4+, CD8+, CD14+, CD19+, and CD56+ cells but not in granulocytes. Next, PCR-analysis was performed on FACS-sorted bone marrow (BM) cells to assess MDR1 expression in different maturational stages. Precursors (CD34+), early and late myeloid cells (CD33+/CD34+, CD33+/CD34-) as well as lymphocytes of the B-cell lineage (CD19+/CD10+, CD19+/CD10-) expressed the MDR1 gene. BM monocytic cells (CD33++/CD34-) were negative, and a very weak signal was detected in erythroid cells (glycophorin A+). Significant Rh-123 efflux was found in CD34+, CD10+, CD33+, and CD33++ BM cells, but not in glycophorin A+ cells. We conclude that PB and BM lymphocytes, PB monocytes, BM progenitors, and immature myeloid cells, but not late BM monocytes, erythroid cells, and PB granulocytes, express MDR1 mRNA and a functional P-gp. These results have to be taken into account when MDR1 expression is determined in tumor samples containing normal blood cells.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1992

The yptV1 gene encodes a small G-protein in the green alga Volvox carteri: gene structure and properties of the gene product.

Small G-proteins encoded by ras-like genes are ubiquitous in eukaryotic cells. These G-proteins are believed to play a role in central processes, such as signal transduction, cell differentiation and membrane vesicle transport. By screening genomic and cDNA libraries of the colonial alga, Volvox carteri f. nagariensis, with ypt DNA probes from Zea mays, we have identified the first member of a ypt gene family, yptV1, within a green alga. The 1538-bp yptV1 gene of V. carteri consists of nine exons and eight introns and has three potential polyadenylation sites 210, 420 and 500 bp downstream from the UGA stop codon. The derived 203-amino-acid polypeptide, YptV1, exhibits 81% similarity with Ypt1 from mouse, with the corresponding genes sharing four identical intron positions. Recombinant YptV1 (reYptV1) produced in Escherichia coli retains the ability to bind GTP after SDS-PAGE and immobilization on nitrocellulose. Immunological studies using polyclonal antibodies against reYptV1 indicate that the protein is present in the membrane fraction of a V. carteri extract and is expressed throughout the whole life-cycle of the alga. Similar to other Ras-like proteins, YptV1 contains two conserved C-terminal cysteine residues suggesting post-translational modification(s), such as isoprenylation or palmitoylation, required for membrane anchoring. The presumptive role of YptV1 in cytoplasmic vesicle transport is briefly discussed.

Amino Acid Sequence↗
PubMed1992

Flow cytometric determination of atypical antigen expression in acute leukemia for the study of minimal residual disease.

The aim of this study was to investigate to which extent acute leukemias could be monitored for residual disease by using atypical antigen combinations as leukemia-related markers. Atypical antigenic features were determined by double color flow cytometry and included coexpression of lymphoid and myeloid related antigens, unphysiological coexpression of immature and mature antigens, and lack of an antigen that is normally expressed during maturation. Atypical immunophenotypes were detected in 35 of 68 patients with AML (51.5%) and 15 of 24 patients with ALL (62.5%). When 12 patients with leukemia-associated markers were again analyzed at relapse, the relevant antigen combinations were retained in 11 of them. The sensitivity of this two color flow cytometric assay as determined in dilution experiments was 1 in 10(3) to 10(4) cells. Follow-up studies of bone marrow samples revealed that, after induction chemotherapy cells with leukemia-associated markers were detectable in several patients at a frequency of 0.5 to 4%, but only patients in whom the cells with atypical antigens never disappeared suffered from relapse. In contrast, patients who became negative for the atypical cells remained in complete remission (median remission duration after the first negative bone marrow assessment by flow cytometry 52 weeks, range 20-102). We conclude that atypical antigen combinations, which are present in a meaningful number of acute leukemias, are a valuable means of monitoring acute leukemia patients during follow-up. This flow cytometric approach can complement other strategies to get a more accurate definition of remission in acute leukemia.

Acute Disease↗
PubMed1992

Thiobacillus plumbophilus spec. nov., a novel galena and hydrogen oxidizer.

From an uranium mine three strains of rod-shaped, mesophilic, chemolithouautotrophic bacteria were isolated. They grow by oxidation of H2S, galena (PbS) and H2. Angelsite (PbSO4) is formed from galena. No ferrous iron is oxidized by the isolates. They grow between pH 4 and 6.5 at temperatures of about 9 to 41 degrees C (optimum around 27 degrees C). The G + C content of the DNA is around 66 mol %. Based on their ability to oxidize sulfur compounds, the new organisms belong to the genus Thiobacillus. No significant homology with Thiobacillus ferrooxidans and Thiobacillus cuprinus was detected by DNA-DNA hybridization. Therefore the new isolates represent a new species within the genus Thiobacillus. Based on the unusual growth on galena, we name the new species Thiobacillus plumbophilus (type strain Gro7; DSM 6690).

Base Composition↗
PubMed1992

Multimodal therapy of small cell lung cancer in TNM stages I through IIIa.

Since 1977, Innsbruck University Hospital has been employing a multimodal therapy concept for small cell bronchial carcinomas in stages I to IIIa. This concept includes all three treatment forms effective in this tumor, namely, chemotherapy, surgery, and radiotherapy. The therapy scheme is stage-dependent and begins in stages T1-3 N0-1 with lung resection and in stage N2 with chemotherapy. To date, 45 patients have been included in a prospective, nonrandomized (phase II) trial: 7 in TNM stage I, 11 in stage II, and 27 in stage IIIa (6 T3 and 21 N2). The actuarial 5-year survival rate of the entire group (including therapy-related lethality, early recurrences, and protocol violations) is 36%; it is 57% for those in stage I, 28% for those in stage II, and 34% for those in stage IIIa. Median survival time is 18 months. Patients with completed multimodal treatment have a 5-year survival rate of 56% regardless of disease stage. Three patients died of tumor-unrelated causes after 47, 52, and 54 months.

Adult↗
PubMed1992

Surface immunoglobulin density in the differential diagnosis of B-cell chronic lymphocytic leukemia and leukemic immunocytoma.

Using flow cytometry peripheral blood samples of 37 consecutive patients with B-cell chronic lymphocytic leukemia (B-CLL) and 17 consecutive patients with leukemic immunocytoma (IC) were studied in order to determine quantitative differences in the surface immunoglobulin (slg) density. In 8/37 (21.6%) cases of B-CLL and 1/17 (5.9%) cases of IC slg staining remained in the control level. Analysis of slg-positive cases demonstrated a close association between the amount of slg and diagnosis: per case the mean calculated fluorescence intensity for IC lymphocytes was 209.7 arbitrary linear intensity units (IU) (median: 156.4, standard error of the mean (SEM): 53.7) and for B-CLL lymphocytes 10.8 IU (median: 7.3, SEM: 1.1; p less than 0.0001). Altogether, 94.6% of all B-CLL patients and 76.5% of all IC patients were correctly classified when a cut-off point was fixed at a mean fluorescence intensity value of 20.0 IU. The percentage of leukemic cells as characterized by CD19 and HLA-DR reactivity was significantly lower in cases of IC (p less than 0.03 and p less than 0.01, respectively). In both entities disease progression occurred more frequently in advanced stages (II-IV) according to the Rai classification (p less than 0.01). In progressive disease rather than in stable disease circulating T lymphocytes were shown to express decreased amounts of surface CD3 antigen (p less than 0.02). We conclude that the quantitative assessment of surface antigens in addition to their qualitative characterization provides accurate information. In particular, the diagnostic discrimination between B-CLL and IC may be improved by determining the lymphocytes' slg amount.

Antigens, CD↗
PubMed1992

Direct demonstration of binding of aggregated mouse IgG1 to the 40-kDa Fc receptor for IgG (Fc gamma RII) in both high and low responders.

Several directly fluorochrome-conjugated murine monoclonal antibodies (mAb) of the IgG1 subclass and directed against B or T cell antigens were found to bind to monocytes via the 40-kDa Fc receptor for IgG (Fc gamma RII). As expected from the established polymorphism of Fc gamma RII, strong staining was observed in about 75% of individuals. In the remaining 25% staining was clearly weaker, but could be definitely demonstrated with a mAb against the B cell-specific CD19 differentiation antigen. Specificity of binding to Fc gamma RII was confirmed by the ability to block the binding of the CD19 mAb by pre-incubation with aggregated IgG1 or with mAb against Fc gamma RII. The extent of T cell proliferation induced with a CD3 mAb of the IgG1 isotype (a-Leu 4), which is dependent on the interaction of monocyte Fc gamma RII with the Fc portion of the CD3 mAb, exactly correlated with the amount of binding to Fc gamma RII in all individuals. Proliferation was dose-dependent for both high and low responders; cells of low responders did not proliferate at concentrations below 16 ng/ml of mAb, whereas there was a small but unequivocal proliferation at higher concentrations. These results confirm that monocytes from previously characterized "non-responders" are able to bind aggregated murine IgG1 via Fc gamma RII. They also demonstrate that directly labeled mAb can cause extensive nonspecific staining which may not be excluded by the use of control antibodies of the same isotype.

Animals↗
PubMed1992

Detection of activity of P-glycoprotein in human tumour samples using rhodamine 123.

Based on the fluorescent properties of the dye rhodamine 123 (Rh123), which is transported by the membrane efflux pump P-glycoprotein (P-gp), we developed a functional flow cytometric assay for the detection of multidrug-resistant (MDR) cells. Using drug sensitive cell lines (KB-3-1) and MDR mutants (KB-8-5, KB-C1) experimental conditions were established that enabled demonstration of significant differences in Rh123 efflux and accumulation. Subsequently we investigated the applicability of this functional assay for the prediction of MDR in human peripheral blood and bone marrow samples. Using two-colour flow cytometry, the leukaemic blast cells of six patients suffering from acute myeloid leukaemia (AML) were analysed. In three cases the blast cells showed a rapid and marked Rh123 efflux. In the presence of MDR inhibitors these cells retained Rh123. To determine whether the efflux of Rh123 was associated with P-gp expression, the leukaemic cells were stained with the monoclonal antibody MRK-16. In addition extracted RNA was analysed by polymerase chain reaction to evaluate the expression of mdr 1 mRNA. In all three Rh123+ cases mdr 1 mRNA was detectable whereas only one AML case expressed P-gp. In comparing Rh123 with daunorubicin, which also allows the detection of MDR cells, accumulation studies proved Rh123 to be the more sensitive drug for flow cytometric MDR screening. Additionally, two-colour flow cytometry was much easier to perform with Rh123 than with daunorubicin. Our results indicate that flow cytometric measurement of Rh123 accumulation/efflux proves applicable to detect MDR cells in heterogenous clinical samples.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1991

Predictive value of interleukin-6 and neopterin in patients with multiple myeloma.

Concentrations of interleukin-6 and neopterin were measured in sera from 44 patients with multiple myeloma. To judge the relative prognostic value of these analyses, other clinical and laboratory variables were concomitantly determined. The patients were followed up to 9 years, and the abilities of all variables to predict outcome were assessed. Both neopterin (P = 0.0008) and interleukin-6 (P = 0.033) were significantly higher in patients with higher stages of the disease. The correlation between interleukin-6 and neopterin was weak but significant (Spearman's rank correlation coefficient, 0.38; P = 0.019). By univariate survival analysis using the product-limit approach, both neopterin (P = 0.0001) and interleukin-6 (P = 0.025) were identified as significant predictors of survival. Multivariate survival analyses by the proportional hazards technique demonstrated that either stage and neopterin or neopterin and interleukin-6 are useful combinations of predictor variables. Thus, interleukin-6, which is supposed to influence progression of multiple myeloma in an autocrine or paracrine manner, failed to contribute to prediction if stage was included in a model. In contrast, neopterin remained significant in all multivariate models.

Aged↗
PubMed1991

Expression of the c-myc proto-oncogene in multiple myeloma and chronic lymphocytic leukemia: an in situ analysis.

The c-myc gene plays a pivotal role in mediating the competence state for cell cycle transversion. This biologic role is in contradiction to reports of elevated expression of the gene in multiple myeloma, a tumor with restricted self-renewal capacity. To more clearly define the role of this gene in plasma cells of myeloma patients, c-myc messenger RNA (mRNA) and/or oncoprotein expression were semiquantitatively analyzed on the single cell level in 19 cases of multiple myeloma, among them 1 biclonal case and 1 case with coexistent chronic lymphocytic leukemia (CLL). Performing anti-sense/mRNA in situ hybridization, mature c-myc gene transcripts were detected in 92% (12 of 13) of cases and could definitely be attributed to the plasma cells by our study. The number of Ki 67-positive plasma cells actively passing the cell cycle was less than 1% and independent of c-myc gene expression. However, because the presence of the 152-c-MYC epitope was correlated to extent of marrow plasmacytosis (r = .64; P = .043) and content of plasmablasts (P = .09), the c-myc gene might serve a function different from proliferative activity, but also associated with tumor cell mass. In CLL cells (21 of 22 cases) and their benign counterparts, ie, bone marrow and peripheral blood lymphocytes, the anti-sense/c-myc mRNA hybridization signals remained below the threshold considered as cutpoint between negative and positive. The low amounts of c-myc transcripts were correlated to neither stage of disease (P = .52) nor lymphocyte counts (P = .24). Because the numbers of peripheral blood lymphoma cells were independent of tumor mass and of c-myc gene transcripts expressed, peripheral blood lymphocytosis might more likely reflect homing processes than proliferative activity in CLL.

Antibodies, Monoclonal↗
PubMed1991

[Recombinant interferon alpha-2c in Ph-positive chronic myeloid leukemia. Results of a multicenter phase II study].

In a Phase II study, 82 patients with Philadelphia chromosome(Ph)-positive chronic myelogenous leukaemia were treated with 3.5 million I.U./d of recombinant interferon alpha-2c (rIFN). 73 patients have so far been evaluated (42 male, 31 female, mean age 50 [12-87] years). At the start of therapy, 10 were in the accelerated phase (group 1) and 63 in the chronic phase, of whom 19 had received previous treatment with cytotoxics (group 2), while the remainder (group 3, n = 44) had received primary treatment with rIFN. There was short-term stabilization in 7 of the 10 group 1 patients, but none had complete haematological or cytogenetic remission. In contrast, the remission rate (complete or partial haematological remission) was 63% in the previously treated (group 2) and 66% in the previously untreated chronic phase patients (group 3). There was a reduction in the proportion of Ph-positive metaphases in 7 group 2 patients (11%) and in 10 group 3 patients (23%). Complete cytogenetic remission has so far been seen in 2 patients. Cytogenetic improvement occurred after 3 months at the earliest, and in some patients only after 12 to 19 months treatment. Differences in response to treatment were related to stage (prognostic staging system of Kantarjian et al.) in group 3 patients: complete or partial haematological remission was seen in 22 out of 25 patients with stage 1 disease, in 4 out of 7 in stage 2, and in only 3 out of 12 in stages 3 and 4.

Adolescent↗
PubMed1991

Phenotype and topography of human thymic B cells. An immunohistologic study.

Using single and double labeling immunohistochemical techniques and a large panel of monoclonal antibodies against B-cell differentiation antigens, including those newly defined at the Fourth International Leucocyte Typing Workshop, we have examined the immunophenotype and tissue distribution of human thymic B-cells. The existence of a distinct B-cell population as a constant constituent of the thymic microenvironment has been noted only recently. We found a significant population of B-lymphocytes in the thymic medulla expressing the B-cell restricted antigens CD19, CD20, CD22, CD37, CD72, CD76 and IgM and IgD. As with other extrafollicular B-lymphocytes, they differ significantly from both follicle mantle and germinal center cells in morphology and immunophenotype, which points to alternative modes of B-cell differentiation. Thymic B-cells themselves show considerable heterogeneity and a subpopulation with dendritic features and the expression of CD23 has been referred to as "asteroid" cells. Their close association with T-cells and medullary epithelial cells points to a functional role for B-cells in the thymus. A second population of B-lymphocytes together with frequent lymph follicles is found within the extrathymic perviascular space. Though separated from the medulla by a layer of epithelial cells, a clear distinction between the B-cells of these two compartments is not always possible. The intramedullary B-cell compartment shows a parallel numeric increase with the occurrence of germinal centers in the perivascular space, mostly due to an accumulation of B-cells in the medulla adjacent to these lymph follicles. Thus a close relationship between the intra- and extramedullary B-cell population of the thymus seems likely.

Adolescent↗
PubMed1991

Interferon alfa-2b with VMCP compared to VMCP alone for induction and interferon alfa-2b compared to controls for remission maintenance in multiple myeloma: interim results.

The present trial was designed to evaluate whether interferon (IFN) combined with standard induction chemotherapy and/or interferon remission maintenance treatment improve treatment results in patients with multiple myeloma. Up to now 89 patients have received IFN plus vincristine/melphalan/cyclophosphamide/prednisolone (VMCP) as induction therapy, and 86 conventional VMCP. The proportion of patients with progressive disease was significantly lower (P less than 0.005) under IFN + VMCP as compared to the VMCP treatment group. Survival times were significantly longer (P less than 0.02) after IFN + VMCP induction therapy than after VMCP alone. In the second phase of this investigation, 33 progression-free myeloma patients were assigned to receive IFN as maintenance therapy, and 41 patients served as untreated controls. Patients maintained with IFN showed a tendency towards increased progression-free survival. Haematological side effects were observed significantly more often in patients receiving IFN, with more severe haematological toxicity in patients on the combined IFN + VMCP regimen and an increased number of patients with mild haematological toxicity in the group maintained with IFN. Other side effects, such as fever and fatigue, remained within tolerable limits. In conclusion, the preliminary results of this current clinical trial indicate significant advantages of combined IFN + VMCP induction treatment in terms of reduced disease progression and prolonged survival and possible benefits of IFN maintenance therapy in patients with multiple myeloma.

Adult↗
PubMed1991

Thymic B cells.

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B-Lymphocytes↗