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Biomedical subjects

V Horn

Publications and source records attributed to V Horn.

At least 55 records · Page 3Linked to original sources
PubMed1982

Cementoma-like tumours of bone.

The authors summarize the morphological findings on cementoma-like fibromas of long bones registered at the Reference Centre for Bone Tumours in Brno or referred to it. One of the cases registered is described in detail from the submicroscopic point of view. Their experience has shown that cementoma-like fibromas of long bones are genuine bone tumours sui generis, differing to some extent from cementomas of the jaws. The cementicles in such tumours are identical to acellular dental cement and structurally quite different from osteoid.

Adult↗
PubMed1981

Rifampin resistance mutations that alter the efficiency of transcription termination at the tryptophan operon attenuator.

Rifampin-resistant mutants of Escherichia coli were isolated which had altered patterns of resistance or sensitivity to the inhibitory compounds 5-methyltryptophan and 5-methylanthranilate. The levels of tryptophan (trp) operon polypeptides in different rifampin-resistant mutants were elevated or reduced, in a manner consistent with their sensitivity to the two analogs. Complementation tests established that the mutations were in rpoB, the structural gene for the beta subunit of ribonucleic acid polymerase. Introduction of these rpoB mutations into mutant strains which terminate transcription abnormally at the trp operon attenuator established that the rpoB mutations alter trp operon expression by increasing or decreasing transcription termination at the attenuator. The rpoB mutations affected transcription termination at the attenuator only in strains which were able to form what is thought to be a ribonucleic acid termination structure. These findings suggest that alteration of the beta subunit of ribonucleic acid polymerase directly or indirectly affects ribonucleic acid polymerase's recognition of the transcription termination signal at the trp operon attenuator.

DNA-Directed RNA Polymerases↗
PubMed1981

Appendicular skeletal tumours coined by odontogenic terms.

Two intriguing tumours in the appendicular skeleton are coined by odontogenic terms: the "adamantinomas" and "cementomas" (or "cementifying fibromas"). Both are extremely rare, mainly the latter. Eight verified observations are presented here: five adamantinomas and three cementomas. Whereas in adamantinomas, the localization and radiographic picture was very typical in all cases, only one cementoma was found in the metaphysis of a long tubular bone in our survey. Diaphyseal tibial localization in one, and metacarpal in the another patient are the first two atypical localizations, described for this tumor in the world's medical literature. Angiography is characteristic for a benign expansive lesion and should be carried out in all cases. An "en bloc" resection is the intervention of choice for both these entities.

Adolescent↗
PubMed1980

[New experience regarding various forms of osteoclasis (author's transl)].

The authors supplement their 1975 paper on the latest views on osteoclasis with further research on the subject. The complexity of the osteoclastic process is demonstrated, with the participation at times of the nuclei of various bone cells as well as cell organelles, an important role also being played by cell extinction. This complexity of bone resorption relates not only to the endosteal and perosteal bone surfaces, but also appears in osteoclastically active osteocytes. The giant multinuclear cell represents here an absorbent factor, surrounding incompletely demolished bone matrix and cell debris. Submicroscopic histochemical research completes the picture.

Animals↗