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B Gottlieb

Publications and source records attributed to B Gottlieb.

At least 37 records · Page 2Linked to original sources
PubMed1997

The androgen receptor gene mutations database.

The current version of the androgen receptor (AR) gene mutations database is described. The total number of reported mutations has risen from 212 to 272. We have expanded the database: (i) by adding a large amount of new data on somatic mutations in prostatic cancer tissue; (ii) by defining a new constitutional phenotype, mild androgen insensitivity (MAI); (iii) by placing additional relevant information on an internet site (http://www.mcgill.ca/androgendb/ ). The database has allowed us to examine the contribution of CpG sites to the multiplicity of reports of the same mutation in different families. The database is also available from EMBL (ftp.ebi.ac.uk/pub/databases/androgen) or as a Macintosh Filemaker Pro or Word file (MC33@musica,mcgill.ca)

Computer Communication Networks↗
PubMed1996

The androgen receptor gene mutations database.

The current version of the androgen receptor (AR) gene mutations database is described. We have added (if available) data on the androgen binding phenotype of the mutant AR, the clinical phenotype of the affected persons, the family history and whether the pathogenicity of a mutation has been proven. Exonic mutations are now listed in 5'-->3' sequence regardless of type and single base pair changes are presented in codon context. Splice site and intronic mutations are listed separately. The database has allowed us to substantiate and amplify the observation of mutational hot spots within exons encoding the AR androgen binding domain. The database is available from EML (ftp://www.ebi.ac.uk/pub/databases/androgen) or as a Macintosh Filemaker file (MC33@musica.mcgill.ca).

Androgens↗
PubMed1994

Complete androgen insensitivity due to mutations in the probable alpha-helical segments of the DNA-binding domain in the human androgen receptor.

We describe different single-amino acid aberrations in the DNA-binding domain (DBD) of the human androgen receptor (hAR) in three families with complete androgen insensitivity. No additional alteration was found in the translated portion of each mutant gene. In one family, an in-frame 3 nt deletion removes codon 581-(or 582) and, thereby, one of two phenylalanines that invariably occupy adjacent positions in the N-terminal alpha-helical region of the DBD in the steroid/thyroid/vitamin D receptor superfamily. In the second, an in-frame 3 nt loss deletes Arg614, an invariant residue in the C-terminal alpha-helix of the DBD. In the third, a G-->A transition causes Arg614His. Following transient transfection of COS cells with each mutant AR plasmid, there is a normal concentration of specific androgen-binding activity that has a reduced ability to bind two types of androgen response element (ARE), and to transregulate an androgen-responsive human growth hormone reporter gene. In genital skin fibroblasts with delta Phe581 or Arg614His, androgen-binding, AR protein and AR mRNA are markedly reduced; in gonadal fibroblasts with delta Arg614, AR mRNA may be reduced. Our data substantiate the primary contributions of Phe581 and Arg614 to normal hAR-ARE binding, and expose important secondary effects of the mutations affecting each residue.

Amino Acid Sequence↗
PubMed1994

The androgen receptor gene mutations database.

The androgen receptor gene mutations database is a comprehensive listing of mutations published in journals and meetings proceedings. The majority of mutations are point mutations identified in patients with androgen insensitivity syndrome. Information is included regarding the phenotype, the nature and location of the mutations, as well as the effects of the mutations on the androgen binding activity of the receptor. The current version of the database contains 149 entries, of which 114 are unique mutations. The database is available from EMBL (NetServ@EMBL-Heidelberg.DE) or as a Macintosh Filemaker file (mc33001@musica.mcgill.ca).

Databases, Factual↗
PubMed1993

Kinetic evidence for a unique testosterone-receptor complex in 5 alpha-reductase sufficient genital skin fibroblasts and the effects of 5 alpha-reductase deficiency on its formation.

When 5 alpha-reductase-sufficient genital skin fibroblast (GSF) monolayers are incubated with testosterone (T), they first form androgen (A)-receptor (R) complexes that dissociate at a fast rate [k(37 degrees C = 0.024 min-1]. As T is converted to 5 alpha-dihydrotestosterone (DHT), this population of T-R complexes is eventually replaced by one that dissociates much more slowly [k(37 degrees C) = 0.006 min-1], at a rate typical of DHT-R complexes. During the course of T to DHT conversion, one may observe a population of A-R complexes that has a linear (monophasic) intermediate dissociation rate constant [k(37 degrees C) = 0.012 min-1]; this population cannot simply reflect a mixture of T- and DHT-R complexes. The rate at which the complexes are processed from one dissociative form to the next varies with the incubation temperature and the presence or absence of serum in the medium; it also varies within and among GSF strains under apparently constant conditions. To explain these facts, we propose a model that enables the 5 alpha-reductase enzyme to influence the processive dissociative behaviour of T-R complexes by engaging in some sort of coupling with the AR. The proposal is strengthened by a set of observations in cells with constitutive, mendelian or inhibitor-induced 5 alpha-reductase deficiency that preclude a simple quantitative relation between A-R complex processing and the extent of T to DHT conversion.

3-Oxo-5-alpha-Steroid 4-Dehydrogenase↗
PubMed1991

The 56/58 kDa androgen-binding protein in male genital skin fibroblasts with a deleted androgen receptor gene.

Human genital skin fibroblasts (GSF) make a relatively abundant 56/58 kDa protein that binds androgens. The protein shares many properties with the approximately 100 kDa androgen receptor that is encoded by a locus in the q12 region of the X chromosome. It does not appear to be androgen-induced, yet is absent in GSF of most patients with complete androgen insensitivity (CAI). A precursor-product relation with the androgen receptor (AR) protein has been largely excluded; that it may be an unorthodox product of the AR gene has not. The 56/58 kDa protein is made by the GSF of a mentally retarded subject who has CAI because of a complete deletion of the coding portion of the AR gene. Hence, the strong constitutional and statistical correlations that have been demonstrated between the two proteins cannot arise because they share the same gene. The subject's genomic DNA hybridizes normally with 11 single-copy probes from Xq11-Xq13. Therefore, we cannot attribute her mental retardation to a contiguous gene syndrome.

Androgen-Binding Protein↗
PubMed1991

Platelet storage in synthetic media lacking glucose and bicarbonate.

The goal of these studies was to develop a cost-effective medium for the storage at 22 +/- 2 degrees C of platelets for transfusion. Platelet concentrates were prepared from platelet-rich plasma in a standard fashion and resuspended in 55 mL of medium. Residual plasma was 14.4 +/- 4.3 percent of the final suspending solution. The use of a simple solution containing electrolytes and citrate, but no glucose or bicarbonate, was associated with a drop in pH to the range of 6.0 to 6.6, as a result of the production of lactic acid from the platelet glycogen and glucose present in residual plasma. When 25 mM (25 mmol/L) sodium phosphate was included as a buffer, the drop in pH was retarded, but the range throughout storage was still 6.5 to 6.8. Nonetheless, platelets stored for 5 days in this phosphate-containing medium showed satisfactory maintenance of many in vitro variables. However, there was a 10 to 35 percent reduction of in vivo recovery after isotopic labeling. There was no significant reduction in subsequent mean cell life. Because of the in vivo abnormalities, these media are not recommended for use at the present time. However, the results are encouraging and suggest that further research may lead to a satisfactory, cost-effective medium.

Adenosine Triphosphate↗
PubMed1990

The state transitions of normal and mutant androgen-receptor complexes in human genital skin fibroblasts.

We have incubated cells from controls and subjects with receptor-defective androgen resistance with 3H-labelled testosterone (T), methyltrienolone (MT), dihydrotestosterone (DHT) or mibolerone (MB) and studied the temperature dependence of the dissociation rate constants of these various androgen-receptor (A-R) complexes both within cells and after they were extracted from them. In control cells, Arrhenius plots for T-, MT-, DHT- and MB-R complexes were linear and formed a hierarchy of dissociation states with energies of state IV greater than III greater than II, greater than I, respectively. Relative to this hierarchy, the dissociation states of the MB-, DHT- and MT-R complexes in mutant cells were displaced to higher, androgen-inappropriate energies in a mutant-distinctive pattern. When extracted from cells control or mutant T- or MT-R complexes, and mutant (but not control) DHT- or MB-R complexes lowered their respective dissociation rates by undergoing state transitions in conformity with the hierarchy. Hence we propose that different A-R complexes reach different dissociative states by undergoing sequential transitions along a common pathway, and that these transitions are co-regulated both by the chemical characteristics of the bound androgen and by other cellular non-receptor factors.

Cells, Cultured↗
PubMed1990

Androgen receptor defects in patients with minimal and partial androgen resistance classified according to a model of androgen-receptor complex energy states.

We have characterized intracellularly the androgen-receptor (A-R) complexes formed by genital skin fibroblasts from 2 unrelated males with qualitative defects of the androgen receptor: one has a small nonhypospadic penis as part of a syndrome of mild androgen resistance; the other was born with ambiguous external genitalia. The dissociation rate constants of testosterone, methyltrienolone (MT), dihydrotestosterone (DHT) and mibolerone (MB) from normal androgen receptors were determined at various temperatures: when plotted by the method of Arrhenius, they yielded a linear hierarchy of dissociation states with energies of state IV greater than III greater than II greater than I, respectively. Relative to this hierarchy, patient A-R complexes were displaced to higher, androgen-inappropriate energies in a mutant-distinctive pattern. MB- or MT-R complexes of both patients were thermolabile; however, both up-regulated normally in response to prolonged incubation with either hormone. Apparent equilibrium affinity constants (Kd) of the DHT- and MB-R complexes formed by both patients were normal; however, the binding capacity (Bmax) for MB in 1 case was subnormal. The distinctive biochemical phenotypes of A-R complexes in these 2 patients with androgen resistance will facilitate the definition of structure-function relations in the androgen receptor, a classical DNA-binding, transcription-regulating protein.

Adolescent↗
PubMed1987

Extracellular correction of the androgen-receptor transformation defect in two families with complete androgen resistance.

We have characterized the cellular and extracellular phenotype of the mutant androgen receptor (AR) from two families who have complete androgen resistance despite a normal androgen-binding capacity (Bmax) in their genital skin fibroblasts (GSF). The cellular receptors fail to up-regulate their basal AR activity in response to prolonged incubation with 5 alpha-dihydrotestosterone (DHT), or with two synthetic androgens, methyltrienolone (MT) and mibolerone (MB), and form A-R complexes with increased equilibrium (Kd) and non-equilibrium (k) dissociation constants. In addition, they are thermolabile when recently dissociated, but not in their native state. A-R complexes made in normal or mutant cytosol at 4 degrees C elute from DEAE-Sephacel at approximately 0.25 M KCl (untransformed), with or without prior passage through Sephadex G-25; when made in cells at 37 degrees C, extracted with 0.4 M KCl in a buffer containing 10 mM Na2MoO4, and desalted by G-25, they elute at less than or equal to 0.1 M KCl. Normal KCl-extracted DHT- and MB-R complexes dissociate (37 degrees C) at the same slow, linear rate as their in-cell counterparts (transformed); the mutant ones dissociated more slowly than their rapidly-dissociating in-cell counterparts and, to a variable extent, nonlinearly-an early faster phase, a later slower (transformed). Thus, as judged by two conventional criteria of steroid-R complex transformation, the mutant A-R complexes can transform, possibly in two steps, under certain cell-free conditions. This behavior differentiates a class of structural AR mutations whose molecular definition awaits application of recombinant DNA techniques to the X-linked AR locus.

Androgens↗
PubMed1984

Demonstration in situ of subsets of T-lymphocytes in sarcoidosis.

Five biopsy specimens of skin, four of lung, and one of a lymph node were taken from nine patients with sarcoidosis. Monoclonal antibodies were applied to frozen sections of the specimens by an immunoperoxidase technique to test for the presence and distribution of subsets of T-lymphocytes. T-cells expressing the suppressor/cytotoxic phenotype were found predominantly in lymphocytic mantles surrounding sarcoidal granulomas, whereas cells displaying the helper/inducer phenotype were distributed diffusely throughout granulomas. The ratio of helper to suppressor phenotypes in cutaneous sarcoidosis was 5.1 +/- 1.8. The microanatomic location of subpopulations of T-lymphocytes may be important in the pathogenesis of the granulomatous response of sarcoidosis.

Antibodies, Monoclonal↗
PubMed1984

Identification of cells lining pseudovascular spaces of benign pigmented nevi.

So-called pseudovascular spaces, said to occur in 10% of benign pigmented nevi, are presumed to be shrinkage artifacts of tissue processing. In an attempt to characterize the cells lining these spaces, three benign pigmented nevi were studied with immunoperoxidase techniques. It was found that they stained positively with an anti-melanoma antibody, P97a (gamma-2a), but negatively with an antibody against an antigen-related factor VIII, which is a marker for vascular endothelium. We conclude that these spaces are lined by melanocytes of nevi and that the spaces are not truly vascular. In one specimen, the spaces were filled with erythrocytes, which suggest that the spaces were present before fixation. It has been suggested, though, that altered collagen and elastic tissue and the nevi themselves may diminish the resistance of the dermis to the mechanical stress of the biopsy procedure, which results in the formation of these spaces.

Antibodies, Neoplasm↗
PubMed1984

Granuloma annulare. Identification of cells in the cutaneous infiltrate by immunoperoxidase techniques.

To characterize the immunopathologic process of granuloma annulare, frozen sections of eight specimens were evaluated with monoclonal antibodies directed against T lymphocytes and the monocyte-macrophage series, in conjunction with immunoperoxidase techniques and with histochemical staining. The predominant lymphocyte was an activated T lymphocyte (Leu 1+, HLA-Dr+) with an excess of helper-inducer phenotype (Leu 3a+), as compared with suppressor-cytotoxic phenotype (Leu 2a+). OKT-6+ Langerhans' cells were observed in the epidermis, and numerous OKT-6+ cells were observed in the perivascular and granulomatous infiltrate. The use of four monoclonal antibodies, having specificity against peripheral blood monocyte antigens, revealed three different staining patterns in the granulomas. Finally, mast cells were present in perivascular and granulomatous infiltrates. Our results demonstrate that the cutaneous infiltrate of granuloma annulare contains all of the principal cell types that characterize cell-mediated immune responses.

Antibodies, Monoclonal↗