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R Müller

Publications and source records attributed to R Müller.

At least 379 records · Page 21Linked to original sources
PubMed1994

Cloning of embryonal stem cell-specific genes: characterization of the transcriptionally controlled gene esg-1.

We have isolated, by differential library screening, eight cDNAs representing genes that are specifically expressed in the embryonal stem cell line IMT-11, when compared to the parietal endoderm-like cell line PYS-2 or to NIH3T3 fibroblasts. One of these genes, embryonal stem cell gene 1 (esg-1), was analyzed in detail. esg-1 mRNA is found at high levels in both IMT-11 and F9 embryonal carcinoma cells and disappears during the differentiation of the stem cells. Furthermore, expression of the gene was found to be extremely low in, or absent from, oocytes and fertilized eggs, but it is strongly induced at the 2-cell stage, reaching maximum levels at the 4-cell stage. In contrast, esg-1 expression is detectable neither in midgestation embryos nor in neonatal tissues. These results strongly suggest that esg-1 is expressed specifically or at least predominantly in embryonal stem cells. Antibodies directed against a glutathione S-transferase-esg-1 fusion product detect a protein of M(r) approximately 14,000 in F9 embryonal carcinoma cells, but not in differentiated cells. Apart from the esg-1 gene, which contains two introns, there are at least seven esg-1-related pseudogenes in the mouse genome that differ from the esg-1 gene by the presence of multiple point mutations, by the lack of intervening sequences, and/or by the presence of a polyadenylated stretch at the 3' end. The esg-1 gene is under stringent transcriptional control in differentiating and differentiated cells, as shown by both nuclear run-on assays and the transient F9 stem cell-specific expression of constructs consisting of esg-1 upstream sequences fused to a luciferase reporter gene.

Amino Acid Sequence↗
PubMed1994

Inducible regulatory elements in the human cyclin D1 promoter.

To be able to elucidate the function of cyclin D1 in the control of cell cycle progression and its role as an oncogene in tumorigenesis, it is of paramount importance to understand the mechanisms involved in the regulation of its expression. In the present study, we have cloned the human cyclin D1 gene and analysed the structure and function of 3kb of its 5'-flanking region. Several regulatory regions involved in both basal level and serum-induced expression were identified, two of which turned out to be of particular interest. One of these regions is involved in serum induction and is located 848-944 bp upstream of the initiation site. In agreement with this result, in vivo footprinting revealed a novel, strongly inducible protein binding site around positions -928 to -921. A second constitutively occupied binding site was mapped to a potential CRE at position -52. Cotransfection experiments showed that the cyclin D1 promoter is inducible by c-Jun, and that this induction is mediated predominantly through the protected putative CRE at -52.

Base Sequence↗
PubMed1994

Strong transient expression of the type I interferon-induced MxA protein in hepatitis A but not in acute hepatitis B and C.

The human MxA protein is a new specific marker for type I interferon activity both in vitro and in vivo. In the study presented here, this interferon-induced marker, as well as the 2',5'-oligoadenylate synthetases, was measured in circulating mononuclear cells from 21 patients with acute hepatitis A, 20 patients with acute hepatitis B and 14 patients with acute hepatitis C for determination of the activation of the interferon system in these viral diseases. In acute hepatitis A a strong expression (10 of 10 patients) of the MxA protein and the 2',5'-oligoadenylate synthetase activity in peripheral-blood mononuclear cells was observed during the first 2 wk after onset of clinical symptoms. In this period the MxA protein concentrations reached levels similar to those measured in patients treated with up to 5 x 10(6) IU interferon-alpha three times a week. Beyond wk 3, in eight of eight patients with hepatitis A no increased MxA protein levels were found. In contrast, peripheral-blood mononuclear cells from patients with acute hepatitis B contained either no measurable MxA protein or only slightly higher levels of the MxA protein, as did those of most patients (12 of 14) with acute hepatitis C. The MxA protein levels of both hepatitis B and C patients were significantly lower (p < 0.05) than those found in hepatitis A patients. Furthermore, sera from 6 of 10 patients with hepatitis A, but none of 10 patients with acute hepatitis B and C, contained measurable MxA protein. This serum MxA protein may originate from interferon-exposed and subsequently damaged liver cells.(ABSTRACT TRUNCATED AT 250 WORDS)

2',5'-Oligoadenylate Synthetase↗
PubMed1994

Oncogenic activity of cyclin D1 revealed through cooperation with Ha-ras: link between cell cycle control and malignant transformation.

Circumstantial evidence implicates the putative cell cycle regulator cyclin D1 in the process of malignant transformation. Overexpression of cyclin D1 is observed in mammary carcinomas as a result of gene amplification and in parathyroid adenomas and centrocytic B-cell lymphomas as a consequence of chromosomal rearrangements and juxtaposition of the cyclin D1 gene to strong transcriptional control elements. These findings suggest that deregulation of cyclin D1 expression may contribute to malignant transformation in these tumours. To date, however, an oncogenic potential of cyclin D1 has not been demonstrated and the mechanism of its oncogenic activation remains obscure although overexpression of the wild-type protein is likely. We report here that the overexpression of cyclin D1 induces transformation in primary rat embryo fibroblasts in cooperation with activated Ha-ras. Cyclin D1/Ha-ras transformed cells are immortalized, show anchorage independence and give rise to fibrosarcomas in nude mice. Our data directly demonstrate that cyclin D1 is a proto-oncogene that can be activated by transcriptional deregulation. Its previously demonstrated ability to interact with putative cell cycle regulators suggests that cyclin D1 defines a new class of proto-oncogenes.

Animals↗
PubMed1993

[Hepatitis C].

Explore the source record for details and available documents.

Adult↗
PubMed1993

[Active immunization against hepatitis A. Comparison of various immunization schedules].

Three different immunization schedules were compared in 144 young, healthy adults (81 men, 63 women; mean age 28.5 years). They were randomly assigned to one of three groups: group 1, immunization shots on day 0 and day 14 (n = 47), group 2, on day 0 and day 28 (n = 50), and group 3, on day 0, 14 and 28 (n = 47). All participants had a booster shot after one year. The seroconversion rate was 40-46% after first shot, 95-100% after the second one; all were anti-HAV positive after the booster injection. All subjects had specific antibodies in a mean concentration of > 400 IU/l two weeks after the second shot. In almost all subjects antibodies were demonstrable up to the 12th month after the first immunization (> 20 IU/l). Mean antibody concentration during the interval between the second and third immunization after basal immunization on day 0 and 14 or 0 and 28, respectively, was comparable. Three initial immunizations 14 days apart did not achieve much higher anti-HAV levels. The vaccine was equally well tolerated in all three groups. Thus basal immunization shortened to two injections two weeks apart presents a good alternative to the standard scheme of two injections four weeks apart. Three injections two weeks apart bring no demonstrable advantage.

Adult↗
PubMed1993

CD7- T cells represent a subset of normal human blood lymphocytes.

In the peripheral blood of normal adults we identified a subpopulation of mature human T cells that lacks expression of CD7. These CD3+CD7- T cells represent 9% +/- 3.4 SD of PBMC as estimated by analyses of 38 different normal donors. The majority of CD7- T cells express TCR alpha/beta, and are of CD4 helper and CD45RO+CD45RA- "memory" phenotype as determined by three-color fluorescence analysis. We established seven CD4+CD7- T cell clones in vitro from purified CD7- blood T cells and compared these cells to CD4+CD7+ clones. Nonexpression and expression, respectively, of CD7 was a stable feature of all clones during long term culture for more than 6 mo. No CD7 mRNA could be detected by dot blot and Northern blot analysis of purified CD7- T cells and of expanded T cell clones implicating a transcriptional regulation of CD7 Ag expression. Ionomycin/TPA and PHA stimulation were not capable to induce CD7 expression in CD7- cells but up-regulated CD7 expression in CD7+ cells. Whereas CD7- cells of cutaneous T cell lymphoma exhibit a cerebriform nucleus (Sézary cells), no evidence was obtained for cerebriform nuclear morphology in normal CD7- T cells from peripheral blood. We suggest that these CD7- T cells represent a physiologic subset of mature T cells and may be the circulating counterpart of those lymphocytes that are found to be enriched in normal skin and in a variety of benign and malignant skin diseases.

Antigens, CD↗
PubMed1993

Drug assay using antibody mimics made by molecular imprinting.

Ligand-binding assays are used for determination of minute amounts of substances in the bloodstream. Such assays require a receptor that specifically binds the substance of interest. The receptor used is often an antibody, but antibodies require special handling and a costly production procedure. We have used molecular imprinting, a method for creating selective recognition sites in synthetic polymers, to prepare polymers that mimic antibody combining sites. Molecular imprints made against theophylline and diazepam showed strong binding and cross-reactivity profiles similar to those of antibodies. Here we describe a new radiolabelled ligand-binding assay, the molecularly imprinted sorbent assay, which uses antibody mimics. This assay accurately measures drug levels in human serum, with results comparable to those obtained using a well established immunoassay technique. Antibody mimics, which are stable and readily prepared by molecular imprinting, may provide a useful general alternative to antibodies.

Antibodies↗
PubMed1993

[Polycythemia: primary or secondary? The differential diagnostic value of stem cell cultures].

Cultures of hematopoietic precursor cells can be helpful in differentiating between primary polycythemia (polycythaemia vera, PV) and reactive secondary polycythemia: in PV erythroid precursors form hemoglobinized colonies in the absence of added erythropoietin (epo) (= endogenous erythroid colonies), whereas in normals and in patients with secondary polycythemia, formation of erythroid colonies is dependent on added epo. We have performed cultures of peripheral blood precursors from 132 patients with elevated hemoglobin in the presence/absence of added epo. In 48/132 patients we assumed that PV was the cause of polycythemia. In 80/132 patients no endogenous colonies appeared and the polycythemia was judged secondary. 23 PV patients were examined repeatedly. In 18 of them the first diagnosis was confirmed by subsequent cultures; in 5 cases endogenous colonies, which had been present in the first cultures, were no longer detectable. A questionnaire on the subsequent clinical course was sent to 108 treating physicians. 77 questionnaires were answered correctly and returned. In 86% of these patients, our culture diagnosis of PV was either confirmed or another myeloproliferative disorder had been found as a cause of endogenous colonies. In 14% our diagnosis of PV had been false positive. On the other hand, our diagnosis of secondary polycythemia was confirmed in 85% of the patients; its most frequent cause was cigarette smoking and chronic bronchitis and only rarely was it associated with heart or kidney disease. 5/77 patients had persistently elevated Hb without an evident cause, and in 3/77 the Hb normalized spontaneously.(ABSTRACT TRUNCATED AT 250 WORDS)

Colony-Forming Units Assay↗
PubMed1993

Transient renal medullary hyperechogenicity in ultrasound studies of neonates: is it a normal phenomenon and what are the causes?

A prospective ultrasound study of the renal morphology of 51 neonates with no clinical signs of renal impairment showed transient medullary hyperechogenicity of varying intensity in 37%. These findings were made in the first few postnatal days, were not accompanied by any other echographic changes, and disappeared again within the first week of life. They were encountered twice as often in full-term as in premature babies. In parallel with this phenomenon, the concentration of Tamm-Horsfall protein, calcium, and uric acid, and the osmolality were determined in the daily urine of 44 of these neonates. The analyses did not provide any definite clues as to the etiology of the ultrasound findings. It is therefore suggested that the term "Tamm-Horsfall nephropathy or proteinuria" should no longer be used for such sonographic phenomena in the neonatal kidney, but rather, they should be regarded as normal. Furthermore, the term "tubular stasis nephropathy" should be reserved for cases with clinically demonstrable impairment of renal function.

Calcium↗
PubMed1993

[Cephalometric studies on the mandible following the dorsal transposition of the masseter. An experimental animal study].

Changes in growth dimension and growth direction in three to four week old rabbits were studied cephalometrically after surgically repositioning the anterior part of the superficial masseter muscle dorsally to the angle of the mandible (n = 14). Only a sham operation was performed on 13 animals. Twelve months after the procedure the lower jaws were taken out and cleaned by boiling. X-rays were taken of the right and left part of the mandible. All x-rays were measured cephalometrically and the measurements evaluated statistical (alpha = 0.05) with the U-test (Mann/Whiteney). We found a statistically significant shorter mandible and an enlargement of the gonion angle, which indicate a vertical growth direction. The processus condylaris was unchanged. It can be assumed that the growth of the mandible can be altered permanently by muscle reposition, especially in cases with dysmoysis, a term in the literature first proposed by Eschler.

Animals↗
PubMed1993

Neuroendocrine neoplasms of the lung are not associated with point mutations at codon 12 of the Ki-ras gene.

The most prominent abnormality of ras proto-oncogenes in human lung tumours has involved point mutations at codon 12 of the Ki-ras gene. We have analysed 35 tumour samples of neuroendocrine lung neoplasms (ten carcinoid tumours, ten well-differentiated neuroendocrine carcinomas, and 15 intermediate/small cell neuroendocrine carcinomas) for a point mutation at this site. For this purpose, formalin-fixed and paraffin-embedded tissue sections were microdissected to remove non-tumours areas. DNA in the remaining tumour tissue was amplified in vitro by the polymerase chain reaction (PCR) and double-stranded PCR products were subjected to sequence analysis. Neither point mutations at codon 12 nor additional structural alterations at codons 1-32 were detected in Ki-ras gene. Our results suggest that point mutations at codon 12 of the Ki-ras gene do not seem to be involved in the pathogenesis of pulmonary neuroendocrine neoplasms.

Base Sequence↗