Search PubMed⌕ Search

Biomedical subjects

D Agard

Publications and source records attributed to D Agard.

10 recordsLinked to original sources

GCP5 and GCP6: two new members of the human gamma-tubulin complex.

The gamma-tubulin complex is a large multiprotein complex that is required for microtubule nucleation at the centrosome. Here we report the purification and characterization of the human gamma-tubulin complex and the identification of its subunits. The human gamma-tubulin complex is a ring of ~25 nm, has a subunit structure similar to that reported for gamma-tubulin complexes from other species, and is able to nucleate microtubule polymerization in vitro. Mass spectrometry analysis of the human gamma-tubulin complex components confirmed the presence of four previously identified components (gamma-tubulin and gamma-tubulin complex proteins [GCPs] 2, 3, and 4) and led to the identification of two new components, GCP5 and GCP6. Sequence analysis revealed that the GCPs share five regions of sequence similarity and define a novel protein superfamily that is conserved in metazoans. GCP5 and GCP6, like other components of the gamma-tubulin complex, localize to the centrosome and associate with microtubules, suggesting that the entire gamma-tubulin complex takes part in both of these interactions. Stoichiometry experiments revealed that there is a single copy of GCP5 and multiple copies of gamma-tubulin, GCP2, GCP3, and GCP4 within the gamma-tubulin complex. Thus, the gamma-tubulin complex is conserved in structure and function, suggesting that the mechanism of microtubule nucleation is conserved.

Amino Acid Sequence↗

Oestrogen receptor function at classical and alternative response elements.

The oestrogen receptor (ER), bound to classical response elements (EREs) in the promoter of target genes, activates transcription by recruiting coactivator proteins. We will describe structural studies that show that oestrogens allow the formation of a hydrophobic cleft on the surface of the ER that serves as a docking site for coactivators. Anti-oestrogens displace part of the receptor, which then occludes the site, blocking coactivator access. In addition to activating at classical EREs, the ER activates transcription at alternative elements such as AP-1 sites. These bind the Jun/Fos proteins but not ER. Interestingly both oestrogen and tamoxifen activate transcription at AP-1 sites. We propose a mechanism whereby oestrogen and anti-oestrogen allow ER to activate transcription from alternative response elements. ER binds to the coactivators, CBP and GRIP1, that have been recruited by Jun/Fos and through this contact 'triggers' these coactivators into full activity. In this circumstance the ER is part of the coactivator complex for Jun/Fos.

Animals↗

[Syndrome of inappropriate antidiuretic hormone secretion. A report of two cases with hyponatremia and hypouricemia].

Two cases of Schwartz-Bartter syndrome are reported. Both were due to malignant anaplasic tumours of the APUD type with multiple abnormal endocrine secretion, and both were accompanied with hypouricaemia of uncertain significance. The authors believe that the association of hypernatraemia with hypouricaemia should alert clinicians to the possibility of a syndrome of inappropriate antidiuretic hormone secretion (SIADH) of malignant origin.

Apudoma↗

[Gastrointestinal haemorrhage in the cirrhotic. The value of injectable posterior pituitary extract (author's transl)].

The authors report the experience which the have acquired since 1970 in the use of posterior pituitary extract as part of the treatment of gastrointestinal bleeding in cirrhotics. 100 cases have been collected, in 73 patients. These may be divided into two groups: one of 32 patients, who did not receive posterior pituitary extract, with 31 deaths, and one of 41 patients who did receive the extract, with 6 deaths. These figures should be viewed in parallel with the results obtained by other techniques, and it would seem that comparison with other statistics is feasible. In addition, emphasis must be placed upon the simplicity of the administration and surveillance of treatment. Attention is also drawn to the absence of any inherent complication associated with the use of the drug, despite the administration, in certain cases, of high doses.

Gastrointestinal Hemorrhage↗

[Anorectal manifestations of sexually transmissible diseases. Kaposi's sarcoma].

The proctologist is above all concerned with the known recrudescence of venereal diseases. Examples reviewed are diseases of bacterial origin (syphilis, gonorrhea, soft chancre, donovanosis and chlamydiosis), appropriate antibiotic therapy and diseases of viral origin (herpes, condyloma acuminatum). Also noted are other bacterial, viral and parasitic diseases and, indeed, cancers of which Kaposi's sarcoma is the example, even though these are not manifested anorectally. New data on Kaposi's sarcoma, its' relationships with venereal disease and AIDS are presented. With these complex problems, the central role of male homosexuality and lowered cellular immunity widens considerably the professional scope of the proctologist.

Acquired Immunodeficiency Syndrome↗