Transcriptional activation and dimerization functions in the human vitamin D receptor.

The C-terminal domain of the human vitamin D receptor (hVDR) is essential for dimerization with retinoid X receptors and for transcriptional activation. To define the dimerization domain of the hVDR, a series of internal deletion mutants of the receptor were prepared beginning within the E domain and extending through the F domain to the C terminus. These mutant receptors were tested for dimerization and transcriptional activities by means of gel shift assay and beta-galactosidase assay, respectively, in a yeast system.

Identification of a novel mutation in hereditary vitamin D resistant rickets causing exon skipping.

Objective: Hereditary vitamin D resistant rickets (HVDRR) is an autosomal recessive disorder resulting in target organ resistance to the actions of 1,25-dihydroxyvitamin D3 (1,25(OH)2D3). In many cases, this disorder has been shown to be due to mutations in the gene encoding vitamin D receptors (VDR). In a patient with characteristic features of this disorder, we investigated the functional defect and sequenced the coding region of the gene for mutations.

Estrogen modulates the recruitment of myelopoietic cell progenitors in rat through a stromal cell-independent mechanism involving apoptosis.

Loss of ovarian function leads to a significant increase in the number of bone-resorbing osteoclasts. Estrogen replacement is known to manifest bone protective effects in the treatment of postmenopausal osteoporosis. In the present study, we used ovariectomized rats to examine the effects of estrogen loss at the osteoclast progenitor colony forming unit-granulocyte macrophage (CFU-GM) level.

Human vitamin D receptor-dependent transactivation in Saccharomyces cerevisiae requires retinoid X receptor.

Transcriptional and DNA binding activities of the human vitamin D receptor (hVDR) were examined in the yeast Saccharomyces cerevisiae. In the studies described here, VDR itself exhibited little transcriptional activity regardless of the nature of the vitamin D-responsive elements (VDREs) used. Consistent with its lack of functional activity, recombinant VDR was unable to bind to VDREs in vitro using bandshift analysis.

Inhibition of vitamin D receptor-retinoid X receptor-vitamin D response element complex formation by nuclear extracts of vitamin D-resistant New World primate cells.

Most New World primate (NWP) genera evolved to require high circulating levels of steroid hormones and vitamin D. We hypothesized that an intracellular vitamin D binding protein (IDBP), present in both nuclear and cytoplasmic fractions of NWP cells, or another protein(s) may cause or contribute to the steroid hormone-resistant state in NWP by disruption of the receptor dimerization process and/or by interference of receptor complex binding to the consensus response elements present in the enhancer regions of steroid-responsive genes. We employed electromobility shift assay (EMSA) to screen for the presence of proteins capable of binding to the vitamin D response element (VDRE).

Leukemia inhibitory factor as a mediator of JAK/STAT activation in murine osteoblasts.

A number of cytokines have been shown to exert their effects via a recently discovered signaling cascade. One step in this pathway is mediated by a family of nonreceptor protein tyrosine kinases, the Janus kinases or JAK kinases, which become phosphorylated upon ligand-receptor binding and receptor phosphorylation. This in turn is followed by phosphorylation of certain members of a family of latent transcription factors, called signal transducers and activators of transcription (STATs), which subsequently enter the nucleus, bind to DNA in a sequence-specific fashion, and modulate transcription.

Retinoid X receptor acts as a hormone receptor in vivo to induce a key metabolic enzyme for 1,25-dihydroxyvitamin D3.

We demonstrate here that RNA levels of 25-hydroxy-vitamin D3-24-hydroxylase (24-(OH)ase), a key catabolic enzyme for 1,25-dihydroxyvitamin D3, are increased by a highly selective retinoid X receptor (RXR) ligand, LG100268, in mice within hours. Correspondingly, upon LG100268 treatment, kidney 24-(OH)ase enzymatic activity increases 5-10-fold. The endogenous retinoid hormones, all-trans-retinoic acid and 9-cis-retinoic acid, and the synthetic retinoic acid receptor-selective compound, TTNPB, also stimulate 24-(OH)ase.

Targeted eradication of ovarian cancer mediated by intracellular expression of anti-erbB-2 single-chain antibody.

Objective: Overexpression of the tyrosine kinase receptor erbB-2 is important in the pathogenesis of a variety of neoplasms including ovarian cancer. As a strategy to selectively eradicate erbB-2-overexpressing tumor cells, an anti-erbB-2 single-chain immunoglobin (sFv) gene was constructed to direct expression of intracellular anti-erbB-2 antibody. The purpose of this study is to establish the antitumorigenicity of this strategy in in vitro and in vivo models.

Audit of post-operative auto-transfusion of shed blood in hip arthroplasty.

Auto-transfusion of shed blood for joint arthroplasty has several theoretical advantages: availability, compatibility, avoidance of transmission of infection and cost. The clinical records of 92 primary hip arthroplasties were reviewed to investigate the effect of auto-transfusion on the use of the National Blood Transfusion Service both in terms of blood ordered and subsequently used. Overall, post-operative auto-transfusion had no significant effect on blood ordering or usage and was very expensive.

Analysis of estrogen receptor function in vitro reveals three distinct classes of antiestrogens.

We have developed a series of in vitro models with which to evaluate the biological activity of estrogen receptor (ER) agonists and antagonists. Using a protease digestion assay we show that the conformational changes induced within ER are distinct for agonists and antagonists. However, this assay is unable to discriminate between pure antagonists like ICI164,384 and partial agonists such as 4-OH tamoxifen or keoxifene.

Genetics of a-agglutunin function in Saccharomyces cerevisiae.

The Saccharomyces cerevisiae cell adhesion protein a-agglutinin is composed of an anchorage subunit (Aga1p) and an adhesion subunit (Aga2p). Although functional a-agglutinin is expressed only by a cells, previous results indicated that AGA1 RNA is expressed in both a and alpha cells after pheromone induction. Expression of the Aga2p adhesion subunit in alpha cells allowed a-agglutinability, indicating that alpha cells express the a-agglutinin anchorage subunit, although no role for Aga1p in alpha cells has been identified.

Platinum plus cyclophosphamide plus radiotherapy is superior to platinum alone in 'high-risk' epithelial ovarian cancer (residual negative and either stage I or II, grade 3, or stage III, any grade).

Patients with epithelial ovarian cancer (EOC) referred to our institution are stratified into risk groups based on their stage, grade and presence of residual cancer, with a specific treatment policy for each group. One-hundred and thirty-one patients with no visible residual tumor following primary surgery and either stage I, grade 3; stage II, grade 3; or stage III, any grade EOC were treated between November 1983 and the end of December 1991. Regimen A (cisplatin 75 mgm-2 and cyclophosphamide 600 mgm-2 intravenously every 4 weeks for 6 cycles with abdominopelvic irradiation between cycles 3 and 4) was used until April 1989 and was then replaced with Regimen B (cisplatin 75 mgm-2 intravenously every 3 weeks for 6 cycles).

Potent vitamin D3 analogs: their abilities to enhance transactivation and to bind to the vitamin D3 response element.

1,25 dihydroxyvitamin D3 [1,25(OH)2D3] mediates its biological activities through specific binding to the vitamin D3 receptor (VDR) and subsequent association with vitamin D3 responsive elements (VDRE) in genes modulated by 1,25(OH)2D3. Several novel vitamin D3 compounds (Cmpds) have recently been identified which have 5- to 1000-fold greater abilities to induce differentiation and to inhibit proliferation of HL-60 leukemic blast cells as compared to the parental 1,25(OH)2D3 (code name, Cmpd C). To clarify the mechanism by which five of these vitamin D3 analogs [1,25(OH)2-16ene-D3, (Cmpd HM); 1,25(OH)2-16ene-23yne-D3, (Cmpd V); 1,25(OH)2-16ene-23yne-26,27 F6-D3; 22-Oxa-1,25(OH)2D3; 1,25(OH)2-23yne-D3] mediate their remarkably potent biological activities, we have investigated their abilities in HL-60 cells to transactivate a chloramphenicol acetyl transferase (CAT) reporter gene containing a VDRE from the human osteocalcin gene attached to a thymidine kinase minimal promoter.

A carcinoembryonic antigen polynucleotide vaccine for human clinical use.

We have constructed a plasmid DNA encoding the full-length complementary DNA for human carcinoembryonic antigen (CEA) under transcriptional regulatory control of the cytomegalovirus early promoter/enhancer (pCEA) and demonstrated that this plasmid can function as a polynucleotide vaccine to elicit a CEA-specific immune response. This immune response protects against tumor challenge with syngeneic CEA-transduced colon carcinoma cells in mice. In the present work, the pCEA construct and purification method were modified to eliminate nonessential viral sequences, the ampicillin selectable marker, mutagens, and endotoxin to produce a reagent suitable for human clinical trials.

Small cell carcinoma of the cervix treated with concurrent radiotherapy, cisplatin, and etoposide.

A multimodality regimen of four cycles of cisplatin and etoposide with concurrent locoregional radiotherapy (XRT) has been, since May 1988, the standard therapy for women with small cell carcinoma of the cervix (SCCC). Prophylactic cranial irradiation was to be used in all but primary progressors. All 11 patients (median age 47; 4 with pure SCCC and 7 with mixed histology) seen by us were treated with this regimen.

Tissue specificity and mechanism of vitamin D receptor up-regulation during dietary phosphorus restriction in the rat.

Dietary phosphorus restriction up-regulates intestinal vitamin D receptor (VDR), but the tissue specificity of the up-regulation and the mechanism of receptor accumulation remain unknown. Therefore, the effects of low phosphorus diet (LPD) on VDR content in intestine, kidney, and splenic monocytes/macrophages were examined. Male Sprague-Dawley rats weighing 50-100 g were fed a normal diet (NPD; 0.

Effect of vitamin and trace element supplementation on immune indices in healthy elderly.

Aging is associated with a progressive decline in the immune system and a greater susceptibility to infection. This double-blind, placebo-controlled study, examined the effect of a vitamin and trace element supplement on immune responses of healthy, noninstitutionalized elderly subjects. Forty-seven subjects aged 61-79 years were randomly assigned to receive placebo or micronutrient supplementation for one year.

Analysis of regulatory regions in the COL1A1 gene responsible for 1,25-dihydroxyvitamin D3-mediated transcriptional repression in osteoblastic cells.

The synthesis of type I collagen in bone cells is inhibited by the calcium-regulating hormone 1,25-dihydroxyvitamin D3. Earlier work from our laboratories has indicated that vitamin D regulation is at the level of transcription, based on results from both nuclear run-off assays and functional promoter analysis of a hybrid gene consisting of a 3.6 kb COL1A1 promoter fragment fused to the chloramphenicol acetyltransferase reporter gene.

Activation of the human osteocalcin gene by 24R,25-dihydroxyvitamin D3 occurs through the vitamin D receptor and the vitamin D-responsive element.

1 alpha-25-dihydroxyvitamin D3 [1 alpha,25(OH)2D3], together with vitamin D receptor (VDR), directly activates human osteocalcin (hOC) gene expression through a vitamin D-responsive element (VDRE) located in the promoter of the hOC gene. We investigated the effect of 24R,25-dihydroxyvitamin D3 [24R,25(OH)2D3] on the regulation of the hOC gene promoter and compared it with that of 1 alpha,25(OH)2D3. 24R,25(OH)2D3 did not activate the natural promoter in VDR-negative CV-1 cells.

Partial sleep deprivation reduces natural killer cell activity in humans.

Sleep disturbance, measured by either subjective report or electroencephalographic (EEG) assessment of sleep, correlates with a reduction of natural killer (NK) cell activity in major depression. To test whether sleep loss independent of mood disturbance alters daytime values of cellular immune function, the effect of late-night partial sleep deprivation on NK cell activity was studied in 23 medically and psychiatrically healthy male volunteers. After a night of sleep deprivation between 3 and 7 AM, NK cell activity was reduced in 18 of the 23 subjects with average lytic activity reduced significantly (p < .

Fractures of the humeral capitellum: Herbert screw fixation.

During the first half of 1991, five patients with displaced fractures of the humeral capitellum were managed by open reduction and fixation of the capitellar fragments with Herbert bone screws. All patients had stable, painfree elbows at follow-up, with no restriction of normal daily activities. There were no evidence of early avascular necrosis of capitellar fragments, even where soft tissue attachments of small fragments had been injured.

Sensitive and specific detection of retinoid receptor subtype proteins in cultured cell and tumor extracts.

Subtype-specific antipeptide antibodies have been developed against each of the retinoic acid receptors (RARs alpha, beta, and gamma) and each of the retinoid X receptors (RXRs alpha, beta, and gamma). Each antibody reacts specifically with its respective recombinantly expressed protein but not with any of the other retinoid receptor subtypes, by both immunoblot and immunoprecipitation technology. We describe a sensitive and specific assay that combines the binding of cultured cell and tumor extracts to [3H]all-trans-retinoic acid or [3H]9-cis-retinoic acid with immunoprecipitation of the hormone-receptor complexes by the subtype-specific antibodies to determine the levels of functional retinoid receptor subtype proteins that are present.

Factor VII antigen levels in a healthy blood donor population.

We determined factor VII antigen (FVIIag) levels in 705 healthy blood donors ranging in age from 17 to 79 years using a two-site solid-phase enzyme immunoassay developed in our laboratory. The mean (+/- SD) FVIIag level for the total population was 102 +/- 31%. FVIIag levels for men (n = 375) and women (n = 330) were 101 +/- 28% and 103 +/- 33%, respectively.

1,25-dihydroxyvitamin D3 modulates phosphorylation of serine 205 in the human vitamin D receptor: site-directed mutagenesis of this residue promotes alternative phosphorylation.

The vitamin D receptor (VDR) from a variety of animal species is a hormone-modulated substrate for phosphorylation in vivo. In this report, we utilize an expression vector to produce recombinant human VDR (hVDR) in 1,25-dihydroxyvitamin D3-treated COS-1 cells. Immunoprecipitation of the phosphorylated hVDR followed by gel purification and phosphoamino acid analysis revealed modification exclusively on one or more serine residues, consistent with previous studies of the VDR in other species.