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Biomedical subjects

G Thom

Publications and source records attributed to G Thom.

17 recordsLinked to original sources
PubMed2001

A conserved role of a DEAD box helicase in mRNA masking.

Clam p82 is a member of the cytoplasmic polyadenylation element-binding protein (CPEB) family of RNA-binding proteins and serves dual functions in regulating gene expression in early development. In the oocyte, p82/CPEB is a translational repressor, whereas in the activated egg, it acts as a polyadenylation factor. Coimmunoprecipitations were performed with p82 antibodies in clam oocyte and egg lysates to identify stage-regulated accessory factors. p47 coprecipitates with p82 from oocyte lysates in an RNA-dependent manner and is absent from egg lysate p92-bound material. Clam p47 is a member of the RCK/p54 family of DEAD box RNA helicases. Xp54, the Xenopus homolog, with bona fide helicase activity, is an abundant and integral component of stored mRNP in oocytes (Ladomery et al., 1997). In oocytes, clam p47 and p82/CPEB are found in large cytoplasmic mRNP complexes. Whereas the helicase level is constant during embryogenesis, in contrast to CPEB, clam p47 translocates to nuclei at the two-cell stage. To address the role of this class of helicase in masking, Xp54 was tethered via 3' UTR MS2-binding sites to firefly luciferase, following microinjection of fusion protein and nonadenylated reporter mRNAs into Xenopus oocytes. Tethered helicase repressed luciferase translation three- to fivefold and, strikingly, mutations in two helicase motifs (DEAD--> DQAD and HRIGR-->HRIGQ), activated translation three- to fourfold, relative to MS2. These data suggest that this helicase family represses translation of maternal mRNA in early development, and that its activity may be attenuated during meiotic maturation, prior to cytoplasmic polyadenylation.

Amino Acid Sequence↗
PubMed1997

The selection in vivo and characterization of an RNA recognition motif for spectinomycin.

Ribonucleoprotein (RNP) complexes participate in almost all macromolecular processes, including RNA processing, protein synthesis, and the signal recognition of proteins targeted for export. An understanding of these processes requires detailed knowledge of interactions at the molecular level, which has evidently been difficult due to the size and complexity of the particles. Fragmentation of large RNP complexes into functional subdomains is proven to be a successful in vitro strategy to probe ligand interactions at the molecular level. We reasoned that RNA molecules expressed in vivo may fold in such a manner as to mimic a drug binding site present on the intact ribosome. If expressed at sufficient levels, the RNA would sequester the antibiotic thereby permitting the continued function of the ribosome and consequently allow the cell to survive in the presence of the drug. Evidence is presented here in support of this RNA fragment-rescue concept following the selection and characterization of RNA fragments that confer resistance to the antibiotic spectinomycin.

Anti-Bacterial Agents↗
PubMed1996

Antibody reactivity profiles following immunization with diverse peptides of the PERB11 (MIC) family.

PERB11 (MIC) is a gene family possessing multiple copies located within the MHC. Structurally, PERB11 is related to the MHC class I, neonatal IgG Fc receptor (FcRn) and Zn-alpha 2-glycoprotein molecules. The MHC class I family is complex in terms of its genomic arrangement, expression and function, and available evidence suggests that the PERB11 family may be similarly complex. We have adopted an approach to study the expression of such complex gene families by immunizing with multiple peptides and by screening the resulting antibodies against a large range of tissues. The amino acid sequences of PERB11.1 and PERB11.2 as well as those of other related molecules were analysed and compared. Peptides were chosen for immunization based upon (i) loop formation within the equivalent known structure of the MHC class I molecules; (ii) immunogenicity by computer analysis; and (iii) evolutionary relationships. Antibodies in serum from immunized rabbits bound to three out of six peptides used for immunization. ELISA and immunoprecipitation demonstrated binding both to the peptides and to the PERB11.2 recombinant protein. By immunofluorescent staining of various tissues of several species, the three antisera generated overlapping profiles of activity. These included reactions with kidney, small and large intestine, oesophagus, testis, ovary and human neutrophils. This is the first description of antibodies induced by the PERB11 peptides. The extreme complexity of these profiles requires further investigation, but may be explained in terms of antibodies against diverse products of the PERB11 gene family and/or related molecules.

Amino Acid Sequence↗
PubMed1990

[Influence of functional therapy on the gingival recession in patients with wedge shaped defects. A 2.5-year longitudinal study of the etiology of periodontal atrophy].

In 20 patients a free way space of greater than or equal to 1.0 mm and a cuspid protected guidance was formed. A previous study has shown, that prematurity and defective contacts reduce the free way space step by step and induce an artificial clenching. The front teeth was relieved in intercuspal position. The increase sof gingival recessions at the upper jaw was over five times significant slighter in treated patients than one in the 22 men of the control group. There was no significant, differences in the lower jaw. The recessions are represented as a sequence of a chronic biomechanical overloading.

Adult↗
PubMed1990

[Elucidation and control of parafunctions by means of a modified self-observation test by Schulte and their effective treatment by occlusal adjustment and reconstruction].

A modified selfobservation test by Schulte enable us to differ parafunction quantitative as qualitative. By means of it were stated, toothclenching is induced by a missing or insufficient free way space on a large scale. Clenching could be reduced by occlusal adjustment and reconstruction significant about 45 percent. The free way space ought to be greater than or equal to 1 mm. The test is suitable for controlled treatment of temporomandibular joint and myofascial disorders. It could substitute electromyograms in outpatients, Toothclenching dominate with 85 percent before grinding with 27 percent in patients with wedge shaped defects.

Bruxism↗
PubMed1989

[Volume estimation of non-caries related enamel defects].

The volume of wedge shaped defects can be estimated by means of massa suppositoriorum on a plaster cast. The substance are pressed in a graduated pipette. The average relative error is six percent. The absolute error of defects of 2.0, 10.0 respectively 20.0 mm3 ranges from 0.12, 0.6 to 1.2 mm3.

Calcium Sulfate↗
PubMed1989

[Treatment of hypersensibility of the neck of tooth by occlusion correction and removal of parafunction].

Tooth sensitivity, parafunctions and stress were proved in 44 patients with wedge shaped defects significantly more frequent than in 17 patients without ones. A cuspid protected guidance and a sufficient free way space could be found in patients with cervical notch defects evidently fewer. After reestablishment of a cuspid protected guidance and of a sufficient free way space and reduction of parafunctions the sensitivity estimated by means of a dental probe could be removed permanent on a number of teeth after two weeks already. The parafunctions have been detected before by using selfoservations test by Schulte.

Dental Occlusion, Traumatic↗
PubMed1989

[How can the progress of wedge shaped defects be reduced? A longitudinal study of 2.5 years to aetiology].

Malocclusion was removed according to direction by Motsch and Schulte. In addition a sufficient free way space was made. The patient was enlightened on connection between stress and problems, which he can't overcome, and parafunctions. The volumeestimation of wedge shaped defects elicited a significant reduction of 45 percent in regard of the progress. In order to malocclusion and parafunctions play an important part in making cervical notch defects.

Adult↗
PubMed1978

[Placement of the sensitivity tester in "Probaset" and "Probamat D"].

For ergonomical reasons the authors suggest, if a Probamat D unit and a fixed turbine are used, to place the turbine handpiece on the mount destined for the sensibility tester and to manufacture a new holder for the latter. The Probaset unit provides no place for the sensibility tester. Therefore, it is recommended to fit the bracket table with a suitable mount.

Dental Equipment↗
PubMed1975

[Diagnosis of frequent periodontal diseases by the specialist for general dentistry].

It is reasonable to refer a patient to a specialist or a special clinic if the own diagnostic possibilities are not sufficient to elucidate the case. But the own diagnostic possibilities should be fully used to spare the patient unnecessary travelling and loss of time. The most reliable and important symptoms and the local causes of frequent periodontal diseases are described and tabulated. All the symptoms indicated may be verified in any institution by inspection, palpation, measuring of socket depth and radiological examination. In this way the specialist is general stomatology will be aided in establishing a periodontal differential diagnosis.

Diagnosis, Differential↗
PubMedDate not supplied

[Recombinant tissue plasminogen activator in treatment of fulminant meningococcal infection].

This article reports about a young boy with fulminant meningococcal septicemia. Conventional treatment with antibiotics, intensive care and hemostatic drugs hold up vital functions. Because of extensive purpura fulminans with skin necrosis recombinant tissue plasminogen activator (rt-PA) was used. Under this therapy clinical improvement was observed.

Child, Preschool↗
PubMedDate not supplied

Fragmentation of the ribosome to investigate RNA-ligand interactions.

RNA molecules perform a variety of important and diverse functions and, therefore, an understanding of their structure and interaction with proteins and ligands is essential. Large RNA molecules (for example, the ribosomal RNAs) are complex and hence reports describing their fragmentation into functional subdomains has provided a means for their detailed analysis. We present here an in vivo approach to study RNA-ligand interactions. This is based on the concept that an RNA fragment could mimic a drug-binding site present on the intact molecule. Overexpression of the fragment would sequester the drug thereby permitting the continued functioning of the ribosome and, thus, ensuring cell viability. Accordingly, a fragment of 16S rRNA encompassing the spectinomycin-binding domain in helix 34 (nucleotides 1046-1065 and 1191-1211) was cloned and in vivo expression resulted in drug resistance. Furthermore, an RNA fragment lacking flanking sequences to helix 34 was also selected from among a pool of random rRNA fragments and shown to confer spectinomycin resistance. A similar in vitro approach is also described for the analysis of rRNA molecules that interact with the yeast elongation factor 3 (EF-3).

Anti-Bacterial Agents↗