Antiestrogens specifically up-regulate bone morphogenetic protein-4 promoter activity in human osteoblastic cells.

Bone morphogenetic protein-4 (BMP-4) plays an important role in the onset of endochondral bone formation in humans, and a reduction in BMP-4 expression has been associated with a variety of bone diseases. Here we describe, by transient transfection assays in bone cells, that the human BMP-4 promoter recently characterized in our laboratory can be stimulated specifically by antiestrogens but not by estrogens or other steroid hormones. This activity is dependent on the presence of the estrogen receptor (ER)-alpha, although the promoter lacks a consensus estrogen-responsive element. No activity was observed in the presence of ERbeta, but synergy was observed when both ER subtypes were cotransfected. The observed stimulation of BMP-4 promoter activity by antiestrogens appeared bone cell specific and was reversed upon addition of estrogens. Since antiestrogens are known to be effective in hormone replacement therapies for postmenopausal women, this observation may help to develop new strategies for treatment and prevention of osteoporosis.

In vitro expression of bovine opsin using recombinant baculovirus: the role of glutamic acid (134) in opsin biosynthesis and glycosylation.

Expression levels of functional bovine opsin in the insect cell line IPLB-Sf9 using recombinant baculovirus were shown not to depend on the use of novel transfer vectors (pAcRP23, pAcDZ1) that were reported to improve biosynthesis levels of other proteins in this system. A production of 5 micrograms opsin per 10(6) cells (approx. 1.5% of total cell protein) was achieved by batch fermentation of infected cells in spinner cultures. Infection of the cells in the presence of the glycosyltransferase inhibitor tunicamycin led to the synthesis of the complete protein, which, however, now migrated with a substantially lower Mr. This demonstrates that opsin in insect cells also undergoes N-linked glycosylation and allowed partial purification (10-fold) of the resulting rhodopsin by affinity chromatography over Concanavalin A-Sepharose. Through site-directed mutagenesis (rhod)opsin mutants have been obtained allowing dissection of functional domains of opsin. Amino acid substitutions that involved Glu-134 and/or Arg-135 affected the normal biosynthetic process leading in part to nonglycosylated, to a small extent even incomplete, protein. A number of mutations, that involve other charged residues within the second and third transmembrane domain of the protein, had no effect on the biosynthetic processing of the protein. We therefore suggest that the charge-pair Glu-134-Arg-135 is part of an important internal signal sequence and that alterations in this region may result in incorrect membrane translocation and/or folding of the protein.

Therapeutical significance of clopimozide in the treatment of chronic psychotic patients.

This report, which concerns both an open and a double-blind study, describes the activity profile and optimum daily dose of clopimozide (R 29 764) investigated in 40 chronic psychotic patients. The results of the open study indicated that clopimozide represents an equal, if not superior, choice versus the other neuroleptics which the patients had been receiving before the open study. Patients sought more contact with those surrounding them, were less preoccupied with their delusions and hallucinations, and showed a better adapted social behaviour. However, these results were not confirmed by the data from the double-blind study-showing that clopimozide was less superior to the placebo than expected on the basis of the open trial. Two hypotheses are advanced to explain this discrepancy: first, the difference in investigational method and second, possible over-dosage of the drug at an average optimum daily dose of 13.95 mg.