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Biomedical subjects

R Herrmann

Publications and source records attributed to R Herrmann.

At least 19 recordsLinked to original sources
PubMed1992

Multiple drug resistance gene expression in human renal cell cancer is associated with the histologic subtype.

Overexpression of p170 glycoprotein, the product of the multiple drug resistance (mdr) gene, has been associated with resistance to various cytotoxic drugs used in the treatment of human neoplasms. Normal renal epithelial cells express p170 as a function of their secretory capacity. Because renal cell carcinomas (RCC) respond poorly to chemotherapeutic regimens, p170 expression was studied in primary RCC. Such expression was measured in 40 human RCC and normal kidney tissues using immunohistochemical staining with the monoclonal antibody C-219. Staining intensities of the whole tumor and of different areas of the cryostat sections were transformed into digital numbers using an algorithm designed for this purpose. In most tumors, an inhomogeneous staining pattern and a correlation between grade of differentiation and C-219 immunoreactivity was observed. A comparison of the tumors according to their histopathologic subtypes showed clear differences. The means (range) of the staining intensities of the different types of RCC: clear cell carcinoma Grade 1 (n = 3), 2.0 (2.0 to 2.0); clear cell carcinoma Grade 2 (n = 19), 0.8 (0.0 to 2.9); clear cell carcinoma Grade 3 (n = 5), 0.1 (0.0 to 0.2); tubular carcinoma (n = 4), 2.0 (2.0 to 3.0); anaplastic carcinoma (n = 8), 0.05 (0.0 to 0.2); oncocytoma (n = 1), 0.0 (0.0 to 0.0); and normal kidney (n = 40), 0.5 (0.0 to 2.0). The differences between anaplastic, clear cell, and tubular carcinoma were significant (P less than 0.001 by Kruskal-Wallis test). In addition, the difference between the three subgroups of clear cell carcinoma was significant (P less than 0.01). It was concluded that the histopathologic subtypes of RCC correlate with the degree of mdr gene expression, as determined by staining with the C-219 monoclonal antibody.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1992

Therapeutic activity of a thioether-lipid conjugate of 1-beta-D-arabinofuranosylcytosine in human colorectal cancer xenografts.

The thioether-lipid conjugate of ara-C, ara-CDP-DL-PTBA, was tested for therapeutic activity in vivo on the growth of seven different xenografts of human colorectal cancers in athymic nu/nu mice. Treatment was started approximately 3 weeks after s.c. transplantation of the tumor when the tumors measured about 0.5 x 0.5 cm. The animals were randomly assigned to treatment with the drug or saline vehicle. The conjugate was given at single doses i.p. of 250 mg/kg/week for 3 weeks. There was no toxicity of the drug at this dose level as observed by clinical aspect, weight loss, or decrease in survival at the end of an experiment. However, ara-CDP-DL-PTBA was highly active in three of seven xenografts, almost completely blocking tumor growth as long as treatment continued with specific growth delay greater than 2 and T/C less than 25%. There was minor growth delay in two further xenografts and no activity at all in the other two xenografts. In conclusion, ara-CDP-DL-PTBA is active in the treatment of human colorectal cancer xenografts at a non-toxic dose level and thus should be considered for clinical testing.

Animals↗
PubMed1992

[The long-term toxicity of polychemotherapy in successfully treated testicular carcinoma].

Of 55 patients with testicular cancer, treated by combination chemotherapy including cisplatin, 21 (mean age 35 [21-51] years) were reexamined for late sequelae of the chemotherapy 1-9 years later. No patient had a recurrence or second malignancy. They all had normal renal function (renal sequence scintigraphy; creatinine clearance). Seven of 20 patients had a polyneuropathy, nine of 18 had high-tone hearing loss. Two patients became fathers after treatment. In nine of 20 patients the serum concentration of follicle-stimulating hormone was raised to above 20 mU/ml, evidence of germ-cell damage. Six of 13 patients had an abnormal ejaculation following retroperitoneal lymphadenectomy or excision of a residual tumour. There was no evidence of any life-limiting toxicity of the chemotherapy.

Adult↗
PubMed1992

PCR-determined expression of the MDR1 gene in chronic lymphocytic leukemia.

To determine the role the multiple drug-resistance (MDR 1) gene plays in chronic lymphocytic leukemia (CLL), we measured the expression of the MDR 1 gene in 30 patients with this disease. A rapid, highly sensitive, and nonradioactive technique based on the polymerase chain reaction (PCR) was used for that purpose. In this technique, called differential PCR, the target (MDR 1) and a reference gene (beta 2-microglobulin) are co-amplified by PCR from random hexamer-primed cDNA in the same reaction vessel. The level of target gene expression is reflected in the ratio between the intensities of the two resulting PCR product bands, as measured by high-performance liquid chromatography (HPLC). MDR 1 gene expression was detectable in 29/30 (97%) patients with CLL, with a median expression level of 0.36 U (human placenta = 1 U). There was no correlation between expression of the MDR 1 gene and clinical stage, time from diagnosis, absolute lymphocyte count, several lymphocyte surface markers, or prior treatment in the patients analyzed. Immunocytochemical studies of the same material using the monoclonal antibody C219 showed a very low or undetectable expression of the P-glycoprotein in the lymphocytes of all patients studied, whereas granulocytes were significantly more immunoreactive. We conclude that the level of expression of the MDR 1 gene in CLL is generally low, that the removal of granulocytes is important in studies of expression of MDR 1 mRNA in CLL, and that differential PCR provides a rapid and reliable method for quantifying the amount of a specific mRNA, even in very small samples of total RNA.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1992

Mutations in the ras protooncogenes are rare events in renal cell cancer.

Mutations in codon 12, 13 or 61 of one of the three ras genes, Ha-ras, Ki-ras, and N-ras, convert these genes into active oncogenes. To determine the role mutated ras genes play in the carcinogenesis of renal cell carcinoma, we analysed tumour DNA and unaffected renal tissue derived from 55 patients. The polymerase chain reaction technique was used to amplify DNA fragments containing Ki-, Ha-, and N-ras codons 12, 13, and 61. The amplified fragments were then probed on slot-blots with labeled mutation-specific oligomers. A single Ki-ras mutation (codon 12, gly- greater than val) was detected in a patient with a pT2N2M1 tumour. We concluded that ras oncogene mutations do not play an important role in the initiation of renal cell carcinoma.

Adult↗
PubMed1992

Sequential methotrexate and 5-fluorouracil (FU) vs. FU alone in metastatic colorectal cancer. Results of a randomized multicenter trial. The Association of Medical Oncology (AIO) of the German Cancer Society.

Methotrexate (MTX) modulates 5-fluorouracil (FU) in several in vitro and in vivo experimental systems. Results of phase II studies have suggested improved response rates for the sequential application of MTX and FU in colorectal cancer. In a prospective randomized multicenter study we compared sequential MTX (300 mg/m2) and FU (900 mg/m2) using a seven-hour time interval and leucovorin rescue with FU (450 mg/m2/d for five days) in patients with previously untreated metastatic colorectal cancer. Of 172 patients randomized 159 were eligible for survival analysis and 153 for toxicity and response evaluation. Complete or partial response has been seen in 25.3% of patients receiving sequential MTX and FU and in 17.6% of those receiving FU alone (p = 0.11). There have been two long-term survivors, apparently cured by MTX/FU. Overall toxicity was more pronounced with FU alone, but sequential MTX/FU caused four toxic deaths. Median survival and survival rates at one and two years were not significantly different. It is concluded that this schedule of sequential MTX and FU is no more effective than a dose-intensive treatment with FU alone in metastatic colorectal cancer.

Adult↗
PubMed1992

Cellular localization of Nef expressed in persistently HIV-1-infected low-producer astrocytes.

OBJECTIVES: The characterization and localization of HIV-1 Nef highly expressed in permanently infected astrocytes (TH4-7-5) as a model for latent infection of human brain cells. DESIGN: Immunochemical methods are an appropriate tool to investigate expression and localization of cellular proteins. METHODS: Nef expression was analysed by Western blot and immunoperoxidase staining using a panel of monoclonal and polyclonal antibodies. Cellular localization studies were performed by indirect immunofluorescence and subcellular fractionation of TH4-7-5 cells. Myristoylation of Nef was investigated by immunoprecipitation of [3H]myristic acid-labelled cell extract. TH4-7-5 nef gene was cloned and amplified by polymerase chain reaction and the nef nucleotide sequence analysed. RESULTS: Reactivities of various Nef-specific antibodies with Nef antigen in TH4-7-5 cells were demonstrated by Western blot analysis. Immunofluorescence revealed cytoplasmic perinuclear staining of Nef with most antibodies. However, one monoclonal antibody against amino acids 168-175 of Nef showed intense homogeneous nuclear staining in TH4-7-5 cells. Reactivity of this Nef antibody was blocked with recombinant Nef derived from TH4-7-5 cells. After subcellular fractionation, Nef was detected in nuclear, membrane and cytosolic fractions of TH4-7-5 cells. No myristoylated Nef antigen was detectable, perhaps because of a serine residue at position 2 of the TH4-7-5 nef gene instead of the glycine residue required for myristoylation. CONCLUSIONS: Chronically HIV-1-infected astrocytoma cells with restricted virus production express different antigenic forms of Nef, which can be distinguished by their subcellular localization. Variant subcellular targeting of Nef suggests the existence of multiple activities of Nef within HIV-infected cells.

Amino Acid Sequence↗
PubMed1992

Localization and biochemical characterization of the ORF6 gene product of the Mycoplasma pneumoniae P1 operon.

ORF6 represents one of the two open reading frames flanking the P1 attachment protein gene of Mycoplasma pneumoniae in the order ORF4-P1-ORF6 (J.M. Inamine, T.P. Denny, S. Loechel, U. Schaper, C.H. Huang, K.F. Bott, and P.C. Hu, Gene 64:217-219, 1988; J.M. Inamine, S. Loechel, and P.C. Hu, Gene 73:175-183, 1988; C.J. Su, V.V. Tryon, and J.B. Baseman, Infect. Immun. 55:3023-3029, 1987), indicating an operonlike organization. As described previously, we identified two proteins with molecular masses of 40 and 90 kDa (B. Sperker, P.C. Hu, and R. Herrmann, Mol. Microbiol. 5:299-306, 1991) which might represent two cotranslational cleavage fragments of the ORF6 gene product. To determine the site of the putative cotranslational cleavage, the first 10 amino acids of the N terminus of the isolated 90-kDa protein were sequenced. The data are consistent with the DNA-deduced amino acid sequence between amino acid positions 455 and 465 (RAGNSSETDAL). Thus, the cleavage site was identified at amino acid position 455 (R). In this study, the two proteins were localized and biochemically characterized. Both proteins are part of the insoluble fraction of M. pneumoniae as shown by immunoblots of supernatants and pellets of mechanically disrupted cells subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Surface proteolysis followed by SDS-PAGE and Western blot (immunoblot) analysis, covalent labelling of surface-exposed proteins with [125I]iodide and subsequent immunoprecipitation of both radiolabelled proteins, immunofluorescence studies with formalized and living M. pneumoniae, and immunoadsorption experiments provided strong evidence that the 40- and 90-kDa proteins are membrane-associated proteins expressing surface-exposed regions.

Amino Acid Sequence↗
PubMed1992

Construction of an EcoRI restriction map of Mycoplasma pneumoniae and localization of selected genes.

A restriction map of the genome of Mycoplasma pneumoniae, a small human pathogenic bacterium, was constructed by means of an ordered cosmid library which spans the complete bacterial chromosome. The positions of 143 endonuclease EcoRI restriction fragments were determined and aligned with the physical map. In addition, restriction sites for the rare-cutting enzymes XhoI (25 sites), ApaI (13 sites), NotI (2 sites), and SfiI (2 sites) were included. The resulting map consists of 185 restriction sites, has a mean resolution of 4.4 kbp, and predicts a genome size of 809 kbp. In addition, several genes were identified and mapped to their respective genomic EcoRI restriction fragments.

Amino Acid Sequence↗
PubMed1992

Infection of human brain cells by HIV-1: restricted virus production in chronically infected human glial cell lines.

OBJECTIVE: To study expression of HIV-1 in human glial cell lines. DESIGN: Chronically HIV-1-infected glial cell lines were established to evade potential artefacts resulting from unphysiological viral entry (i.e., transfection). These cell lines were used to study viral expression and regulation. METHODS: Chronically infected glial cell lines were established by terminal dilution cloning of human glioma cells exposed to HIV-1. Virus production and expression were assayed by measuring reverse transcriptase activity, p24-antigen levels and syncytia-inducing capacity in C8166 target cells (extracellular), or by indirect immunoperoxidase staining, immunoblot analysis, and p24- and Nef-antigen-capture enzyme-linked immunosorbent assays (intracellular). HIV-long terminal repeat (LTR)-dependent expression of the chloramphenicol acetyltransferase reporter gene was determined in transient transfection assays. RESULTS: Culture supernatant from chronically HIV-1-infected glial cells contained only low levels of virus compared with chronically HIV-infected fibroblasts and T-lymphoma cells. Detailed study of HIV-antigen expression in representative glial cell line TH4-7-5 indicated the presence of all major structural proteins, albeit at low levels, and of Vif, Tat, Rev and Nef. Intracellular levels of Nef exceeded p24-antigen levels by approximately 10-fold. Virus was recovered from TH4-7-5 cells by cocultivation with blood-derived target cells, indicating that low-level virus production is not due to defective provirus. Prominent negative regulatory element (NRE)-mediated suppression of exogenous HIV-LTR activity was observed in TH4-7-5 cells and was unequalled by chronically HIV-producing fibroblast cells or by uninfected fibroblast and glial cells. CONCLUSIONS: Our results suggest that restricted virus production by chronically infected glial cells involves LTR-mediated regulation of virus expression.

Base Sequence↗
PubMed1991

The 'positive-inside rule' applies to thylakoid membrane proteins.

In integral membrane proteins, regions that span the lipid bilayer alternate with regions that are exposed on either side of the membrane. For proteins from the plasma membrane of both prokaryotic and eukaryotic cells it has been shown that the exposed parts follow a 'positive-inside rule': on average, segments that are translocated across the membrane have a 2-4-fold lower frequency of positively charged residues than non-translocated segments. We now present an analysis of proteins from the thylakoid membrane of chloroplasts. It is shown that these proteins have the same charge asymmetry as has been reported for proteins from other membrane systems, with their more highly charged regions facing the stromal compartment.

Amino Acids↗
PubMed1991

alpha Interferon maintenance therapy in patients with low-grade non-Hodgkin's lymphomas after cytoreductive chemotherapy with prednimustine and mitoxantrone.

A combination of prednimustine 100 mg/m2/day orally, days 1-5, and mitoxantrone 8 mg/m2/day intravenously, days 1 and 2, was administered to 19 patients with advanced low-grade non-Hodgkin's lymphoma after failure on or relapse after standard chemotherapy. The prednimustine and mitoxantrone (PmM) regimen was repeated every 4-6 weeks to a maximum of six cycles. Thirteen patients, achieving a complete (4) or partial (9) remission (CR or PR), received two additional courses for consolidation followed by interferon alfa-2b 5 million units (MU) subcutaneously (s.c.) three times weekly until progression or relapse. At the present time, remission duration ranges from 4.5+ to 17.5+ months, with a median of 14.5 months. In a historical comparison to unmaintained first remission preceding the PmM/interferon trial, a tendency towards a longer period of freedom from progression was apparent in the 13 patients receiving interferon maintenance treatment during their second PR or CR. These data provided the basis for a currently ongoing multicentre study randomly comparing initial chemotherapy with PmM versus cyclophosphamide/vincristine (Oncovin)/prednisone (COP) in patients with advanced centroblastic-centrocytic and centrocytic non-Hodgkin's lymphomas, followed by a second randomization in CR and PR patients for maintenance with alpha interferon versus observation only.

Adult↗
PubMed1991

Identification of gene products of the P1 operon of Mycoplasma pneumoniae.

Gene P1 of Mycoplasma pneumoniae, which codes for a major adhesin, is flanked by two sequences with open reading frames designated ORF4 and ORF6 (Inamine et al., 1988b). In order to identify proteins translated from those ORFs, gene fusions between the N-terminus of the RNA replicase of the Escherichia coli bacteriophage MS2 and selected regions of ORF4 and ORF6 were constructed. The corresponding fusion proteins synthesized in Escherichia coli were used to immunize mice. Antisera directed against ORF4-related sequences did not recognize M. pneumoniae antigens in Western blot analysis, but antisera directed against ORF-6-derived fusion proteins reacted with two M. pneumoniae proteins of 40 kDa and 90 kDa. In addition, some of the antisera also recognized proteins that formed in a sodium dodecyl sulphate/polyacrylamide gel a protein ladder between 115 and 145 kDa.

Adhesins, Bacterial↗
PubMed1991

Relative importance of dose, body surface area, sex, and age for 5-fluorouracil clearance.

The pharmacokinetics of 5-fluorouracil (FU) has been investigated in 26 cancer patients; 15 of these patients were pretreated with methotrexate (MTX). FU was given by a constant rate intravenous infusion within 10 min, at doses of 320-960 mg/m2. Total plasma clearance, beta-half-life, and steady-state distribution volume were determined with 43 treatments, based on plasma level measurements up to 90 min after the end of the infusion. Average clearance decreased from 1.3 l/min for 320 to 0.7 l/min for 960 mg FU/m2. Multiple linear regression calculations with dose, body surface area, sex, age, and MTX pretreatment as independent variable and clearance as dependent variable confirmed the dependency of clearance on dose and body surface area but also showed that, with equal FU dose per m2, clearance was higher in males than in females, on the average, by 0.22 l/min. There was also suggestive (although not significant) evidence of a (reducing) influence of age on FU clearance.

Adult↗
PubMed1991

[The course of pregnancy and teratogenicity of antiepileptic agents in 66 patients with epilepsy].

We report on 79 pregnancies in 66 female outpatients with epilepsy. An increase of seizure frequency was significantly more frequent in complex partial seizures than in grand mal seizures and in absences. The reason for these disparities are not clear. In most patients a raised frequency of seizures during pregnancy decreased again after delivery. Carbamazepine was the antiepileptic drug prescribed most frequently followed by valproic acid. The course of the blood levels of carbamazepine and valproic acid was nonuniform during pregnancy. Total concentrations of carbamazepine in cord blood were on average 84.5% of those in maternal blood (n = 22). Valproic acid blood levels were on average 183% of those in maternal blood (n = 15). It is still unclear whether these differences are clinically relevant. During the last weeks of pregnancy we found an increase of the free fraction of carbamazepine and valproic acid. Simultaneously the total protein concentration decreased. Until now these findings are without clinical relevance. The course of labor did not differ from normal population concerning the ratios of spontaneous labor, cesarean section and delivery by forceps. Miscarriage and perinatal mortality were 2.7% each and outnumbered the risk in the general population. In 42.8% of the neonates one to three perinatal complications were observed. The ratio of perinatal complications is not different between patients with monotherapy and combined therapy respectively. There was a tendency to lower values of length, weight and head circumference in the male neonates but not in the female neonates. The risk of minor malformations was 26%, the risk of major malformations was 14% (including one case of suspected malformation) without a discernible correlation with a specific antiepileptic drug.

Abnormalities, Drug-Induced↗