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T Wirth

Publications and source records attributed to T Wirth.

At least 91 records · Page 5Linked to original sources
PubMed1993

Analysis of transcriptional stimulation by recombinant Oct proteins in a cell-free system.

The transactivation potential of several isoforms of the lymphoid-specific transcription factor Oct2 has been analyzed using in vitro transcription. Oct2 can stimulate transcription in B-cell nuclear extracts and in HeLa nuclear extracts depleted of the ubiquitous factor Oct1 by wheat germ lectin affinity chromatography. Activity is observed from both natural and synthetic promoters containing single or multiple copies of the octamer motif ATGCAAAT. Multimerization of this motif does not result in a synergistic transcriptional stimulation, but rather leads to a linear increase in activity. To analyze the various Oct2 isoforms, they were overexpressed in HeLa cells using recombinant vaccinia virus. Although all the isoforms bind similarly to the octamer sequence, they show clear differences in their ability to transactivate transcription. This ranges from a 2-fold stimulation for Oct2.3 to the almost 20-fold effect of the most potent variant Oct2.5. In general the relative activity of the isoforms in vitro reflects that observed in vivo in cotransfection experiments. Interestingly the ubiquitous factor Oct1 is also an efficient activator of transcription in vitro, but only from promoters with multiple octamer motifs. Sarkosyl inhibition studies suggest that both Oct1 and Oct2 function in vitro by stabilizing preinitiation complexes without affecting the reinitiation rate of RNA polymerase II.

Cell-Free System↗
PubMed1993

Ultrasonography in Perthes' disease. Clinical relevance and influence on treatment.

A detailed description of the ultrasonographic findings in the course of Perthes' disease has recently been evolved. Synovitis was a prominent finding in the early stages. Lateral extrusion of the femoral head and signs of healing were found earlier by ultrasonography than by radiography. This has clinical implications. Immobilisation in the acute phase was shown to decrease capsular distension, and treatment using containment can be started earlier. The findings in 25 hips were evaluated in this study and their influence on treatment is discussed.

Child↗
PubMed1993

Transforming growth factor beta and cyclosporin A inhibit the inducible activity of the interleukin-2 gene in T cells through a noncanonical octamer-binding site.

Transforming growth factor beta (TGF-beta) has a growth-inhibitory effect on numerous different cell types of the immune system, including T lymphocytes. We show in this study that the inhibitory action of TGF-beta on T lymphocytes is accompanied by a block of interleukin 2 (IL-2) gene expression which is mediated, at least in part, by inhibition of IL-2 promoter/enhancer activity. The functional analysis of cis-regulatory (proto-enhancer) elements of the IL-2 enhancer/promoter region showed that the most TGF-beta-responsive element maps to its so-called upstream promoter site. The proto-enhancer activity of the upstream promoter site element is also inhibited by cyclosporin A. The upstream promoter site DNA harbors two noncanonical, closely linked binding sequences for octamer and AP-1-like factors. Both sites are involved in the establishment of IL-2 enhancer activity. Since the activity of genuine octamer sites but not that of AP-1-binding sites is also impaired by TGF-beta and cyclosporin A in El4 T lymphoma cells, we conclude that both immunosuppressives interfere with the activity but not the DNA binding of octamer factors in T lymphocytes.

Animals↗
PubMed1993

[Psychometric assessment of defense mechanisms: correlation between questionnaire and expert rating. Initial study of validity].

Within the limits of an epidemiological longitudinal field survey on prevalence and course of psychogenic disorders a high-risk-population suffering from medical psychogenic impairment was investigated. The study was conducted in order to verify an etiological multi-level-model of psychogenic disorders in relation to the socialempiric variables "critical life events" and "social support" as well as the depth psychological oriented construct "personality". Besides other instruments a self rating scale based on Vallant's hierarchical model of defense, i.e. the german adaptation of the DSQ (Defense Style Questionnaire) of Bond and coworkers, was used for the accurate measurement of relevant personality parameters. Although defense processes predominantly work unconscious, manifestations of defense mechanisms could be measured indirectly by means of the rating scale. Its essential dimensions separated clinical patients from a group of healthy controls. Furthermore an immature organisation of defense was found to be related to psychogenic impairment. Concerning self- and expert-rating a significant correlation between "immature defense" and the defense mechanisms "schizoid phantasy", "projection" and "acting out" was proved.

Adult↗
PubMed1992

Functional analysis of defined mutations in the immunoglobulin heavy-chain enhancer in transgenic mice.

We have analyzed the effect of defined mutations in the mouse immunoglobulin heavy-chain enhancer after introduction into the germline of transgenic mice. We have tested a mutation of the enhancer octamer motif, a double mutation of the octamer motif and the microB-site, and a triple mutation in the microE2, microE3 and microE4-sites. All constructs are expressed in the spleen of transgenic mice. Furthermore, expression is exclusively detectable in lymphoid organs and not in several nonlymphoid tissues. Whereas mutations in the microE-sites have a more pronounced effect on transgene activity in thymocytes as compared to bone marrow and spleen cells, the octamer/microB double mutation shows significantly reduced expression levels only in B-cells. Finally, our results demonstrate that the intronic heavy-chain enhancer element does not contribute to the increase steady state levels of heavy-chain mRNA after stimulation of spleen cells with LPS.

Animals↗
PubMed1992

Synovial haemangioma of the knee joint.

Synovial haemangioma of joints are rare, but usually affect the knee joints of children and adolescents. Recurrent swelling, usually due to haemarthrosis, and intermittent pain may be present for a long time before the diagnosis is made. In this case report the common features of the condition are described, with emphasis on the occurrence of atraumatic haemarthrosis in children. The value of arthroscopy in diagnosis is discussed.

Arthroscopy↗
PubMed1992

Ultrasonography in Legg-Calvé-Perthes disease.

Ultrasonography was found to be a valuable investigation in the assessment and management of Legg-Calvé-Perthes disease (LCPD). It was used to assess 23 patients with LCPD in 25 affected hips and was compared with radiographs obtained at the same time. A chronological five-part staging of LCPD is proposed, expressing the degree of flattening and fragmentation as well as reconstitution of the femoral head as seen on ultrasound examination. Thickening of articular cartilage was documented, and associated findings of synovitis and lateral extrusion of the femoral head were evaluated. An intraarticular hip effusion was present in 74% of cases in stages I-II. Lateral extrusion increased from stage II onwards until the healing stage. The phase of reconstitution (stage IV) demonstrated both resorption of the necrotic bone and formation of new immature osteoid tissue. Lateral extrusion and the start of the healing phase can be shown earlier by ultrasonography than by radiography.

Child↗
PubMed1992

Oct2 transactivation from a remote enhancer position requires a B-cell-restricted activity.

Previous cotransfection experiments had demonstrated that ectopic expression of the lymphocyte-specific transcription factor Oct2 could efficiently activate a promoter containing an octamer motif. Oct2 expression was unable to stimulate a multimerized octamer enhancer element in HeLa cells, however. We have tested a variety of Oct2 isoforms generated by alternative splicing for the capability to activate an octamer enhancer in nonlymphoid cells and a B-cell line. Our analyses show that several Oct2 isoforms can stimulate from a remote position but that this stimulation is restricted to B cells. This result indicates the involvement of either a B-cell-specific cofactor or a specific modification of a cofactor or the Oct2 protein in Oct2-mediated enhancer activation. Mutational analyses indicate that the carboxy-terminal domain of Oct2 is critical for enhancer activation. Moreover, this domain conferred enhancing activity when fused to the Oct1 protein, which by itself was unable to stimulate from a remote position. The glutamine-rich activation domain present in the amino-terminal portion of Oct2 and the POU domain contribute only marginally to the transactivation function from a distal position.

Animals↗
PubMed1992

[Participation refusal by probands in an epidemiologic long-term study--sociodemographic, clinical and psychometric findings].

Usually little is known about probands who participated in an epidemiological longitudinal field survey but refused participation in follow-up investigations. For reasons of data protection and on account of the fact that investigative instruments used in longterm field surveys or panel studies are more focused on well defined issues (opinions, attitudes, assessment of behaviors) and less on personality variables, differentiated statements on probands who explicitly refused cooperation can hardly be made. In our epidemiological longitudinal field study on prevalence and course of psychogenic disorders we have a different situation. Within the limits of our study we had the unique opportunity to gain far-reaching information on probands who refused to participate in preceding investigations in regard to sociodemographic, psychometric and clinical variables. The clientele of refusers we present in our paper mainly comprises elderly, married, rather obsessive-compulsive structured, lower-class females. According to our data interactive aspects are equally responsible for reduced cooperativeness. The significance of our findings for the planning and carrying out of epidemiological longitudinal field surveys is discussed.

Adult↗
PubMed1991

Anti-IgM antibodies down modulate mu-enhancer activity and OTF2 levels in LPS-stimulated mouse splenic B-cells.

Stimulation of small, resting, splenic B cells with bacterial lipopolysaccharide (LPS) induces proliferation, differentiation to plasma cell formation, and the expression of immunoglobulin heavy chain (IgH). When this is combined with agents which crosslink surface Ig, differentiation and the induction of surface immunoglobulin are suppressed even though proliferation proceeds. We find that anti-mu antibodies suppresses Ig gene expression of transfected mu constructs, even if either the membrane or secretory segments have been deleted. We examined the effects of anti-mu treatment on the IgH enhancer (IgHE) attached to a heterologous test gene (CAT). Indeed the IgH enhancer alone was subject to anti-mu suppression, while the SV40 enhancer was insensitive. To determine what was responsible for suppression of enhancer function by anti-mu we examined nuclear extracts from stimulated splenic B cells for the presence of sequence-specific DNA binding activities to various sites within the enhancer. We found two specific differences--an induction in mu E5 binding activity, and a reduction in octamer transcription factor 2 (OTF2) binding activity, after anti-mu treatment. Analysis of these cells by in situ immunofluorescence with anti-OTF2 antibodies suggests that the nuclear localization of OTF2 in anti-mu treated cells may change, as well as its absolute level.

Animals↗
PubMed1991

Multiple Oct2 isoforms are generated by alternative splicing.

The interaction of the Oct2 transcription factor with the cognate octamer motif ATGCAAAT is a critical determinant of the lymphoid-specific expression of immunoglobulin genes. Ectopic expression of cloned Oct2 cDNA was shown to be sufficient to reconstitute at least some aspects of this regulation in non-lymphoid cells. We describe the isolation and characterization of multiple cDNAs encoding mouse Oct2 from a mature B-cell line and we show that a variety of isoforms of this transcription factor is generated from a single gene by an alternative splicing mechanism. All the isoforms retain the previously characterized POU-domain and are therefore able to bind to the octamer motif. Different amounts of the various isoforms are present within the same B-cell regardless of the developmental stage of B-cell differentiation and at least some of the isoforms are conserved between mouse and humans. In cotransfection experiments we show that all the isoforms are able to activate an octamer containing promoter element in fibroblasts revealing an unexpected functional redundancy. Finally, we show that one of the isoforms encodes the previously described lymphoid-specific Oct2B protein which has been suggested to be involved in the function of the octamer motif in the context of the immunoglobulin heavy-chain (IgH) enhancer.

Amino Acid Sequence↗
PubMed1991

[Wound secretions in standard orthopedic surgery interventions using a new kind of closed vacuum drainage. A report of experiences].

One year's experience with 400 closed Redyrob drainage systems in 267 male and female patients has yielded encouraging results, which led to the replacement of the drainage system formerly used in the orthopaedic university clinic in Marburg by the new system. This makes it possible to regulate the suction strength between 0 and 900 mbar and to couple two suction tubes with one container. Drainage without suction and changing of the containers, which may be necessary in the case of large wound surfaces, can be performed without opening the system, which would endanger both patients and clinic personnel. Additional containers were only needed in 2.3%, because of the better filling volume. Thus, the new drainage system also proved to be superior with respect to cost efficiency and disposal. The total amount of wound secretion never exceeded 1620 ml, depending on the type of surgery performed, and there were no cases of infection or bleeding complications. The suction was regulated in 74% of all systems, and after most of the operations for insertion of endoprostheses. The handling of the systems was classed by the staff on the ward as "very good" or "good" in 96% of all cases. These results are discussed in the light of important aspects of wound drainage already mentioned by other authors.

Adult↗
PubMed1988

Nuclear factor NF-kappa B can interact functionally with its cognate binding site to provide lymphoid-specific promoter function.

Enhancers and promoters, cis-acting regulators of mammalian gene expression, are modular units containing multiple short binding sites for specific trans-acting transcription factors. To investigate if factors binding to enhancer sequences are functionally different from promoter-binding factors, we asked if a short DNA sequence element in the immunoglobulin kappa (kappa) light chain enhancer that binds to the nuclear factor NF-kappa B could also serve as a functional promoter element. A synthetic oligonucleotide containing this binding site was placed in either orientation upstream of the beta-globin TATA-element. In myeloma cells, the NF-kappa B binding site efficiently directed transcription. The promoter activity was directly correlated with the presence of the nuclear factor NF-kappa B: there was no transcription in fibroblasts or in unstimulated pre-B cells where the factor was absent. Transcription could be stimulated in pre-B cells by treatments known to activate NF-kappa B. Thus, the same nuclear factor can act as a positive activator of both enhancer and promoter function, suggesting that the two functions involve similar events in the transcription process.

Animals↗
PubMed1985

Structure and genomic organization of a new family of murine retrovirus-related DNA sequences (MuRRS).

A new class of murine retrovirus-related sequences (MuRRS) is described. These 5.7 kb long transposon-like DNA-elements start and end with approximately 600 bp long repeats identical to previously identified solitary LTR-like elements (LTR-IS). There are about 50 - 100 5.7 kb elements and about 500 - 1000 solo LTR-IS elements per mouse haploid genome. Sequence analysis of one cloned MuRRS element revealed several possible open reading frames with partial sequence homologies to retroviral gag, pol and env genes.

Animals↗
PubMed1984

Evidence for mobility of a new family of mouse middle repetitive DNA elements (LTR-IS).

Locus variation and sequence conservation of mouse LTR-IS elements, a new family of middle repetitive DNA sequences was studied. It is shown that LTR-IS sequences are present in all the inbred strains and subspecies of M. musculus tested and in M. cooki and M. caroli. Their arrangement in mouse genomes is polymorphic. Southern blot analysis and DNA sequencing revealed the existence of homologous DNA sequences with and without LTR-IS element insertion. LTR-IS sequences therefore appear to have arisen in early mouse ancestors and have, at least at some point, been mobile.

Animals↗
PubMed1984

Evidence that a major class of mouse endogenous long terminal repeats (LTRs) resulted from recombination between exogenous retroviral LTRs and similar LTR-like elements (LTR-IS).

Two endogenous retroviral long terminal repeats (LTRs) were sequenced and compared to LTR-IS (a family of insertion-element-like sequences with structural features of solitary retroviral LTRs) and to Moloney murine leukemia virus DNA. The sequence comparisons revealed that the major difference between these two endogenous LTRs is a 190-base-pair segment which is also present in LTR-IS elements. Hybridization analysis of DNAs from several mouse species using specific probes shows linkage of the 190-base-pair segment to a LTR-IS specific fragment. It is concluded that the major class of endogenous LTRs has been generated by recombination between exogenous retroviral LTRs and LTR-IS sequences.

Animals↗
PubMed1983

Family of middle repetitive DNA sequences in the mouse genome with structural features of solitary retroviral long terminal repeats.

Screening of a 129/J mouse genomic library under nonstringent hybridization conditions with a xenotropic virus-like long terminal repeat (LTR) probe revealed a family of sequences resembling insertion elements (IS) with structural features of solitary retroviral LTRs; these are called LTR-IS. They are interspersed among variable flanking regions of mouse DNA and lack any viral structural genes. LTR-IS elements start and end with 11-base-pair inverted repeats and contain signals implicated in RNA polymerase II transcriptional regulation: C-C-A-A-T, T-A-T-A-A-A, and A-A-T-A-A-A. The members of the family are homologous, but not identical, approximately equal to 500-base-pair-long elements with 4-base-pair target-site duplications on both sites of the element. There are 500 LTR-IS per mouse haploid genome.

Bacteriophage lambda↗