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Biomedical subjects

A Barberis

Publications and source records attributed to A Barberis.

11 recordsLinked to original sources
PubMed1992

Gonadotropin evaluation in the diagnosis of polycystic ovary syndrome using either a monoclonal or a polyclonal antibody radioimmunoassay.

The LH/FSH ratio values between gonadotropins dosed with a monoclonal antibody assay (IRMA) in the micropolycystic ovary syndrome (PCOS), are discussed and compared to those obtained with the classic assays using polyclonal antibodies. Because of the higher selectivity of this IRMA assay it is noteworthy that the cut-off value between normal and PCOS patients is now equal to or above one. The evaluation of the LH/FSH ratio between the peak values of the two gonadotropins after a GnRH 100 micrograms iv bolus, may be useful in the diagnosis of PCOS in those patients who present an LH/FSH less than 1 in basal conditions even in the presence of clinical and ecographic aspects of PCOS.

Adolescent↗
PubMed1990

A novel B-cell lineage-specific transcription factor present at early but not late stages of differentiation.

A novel B-cell-specific transcription factor, BSAP, was identified as a mammalian homolog of the sea urchin protein TSAP, which interacts with the promoters of four tissue-specific late histone H2A-2 and H2B-2 genes. As shown by mobility-shift, methylation interference, and mutational analyses, the mammalian protein BSAP recognizes all four sea urchin binding sites in a manner indistinguishable from TSAP; however, the two proteins differ in molecular weight. BSAP is exclusively restricted to the B-cell lineage of lymphoid differentiation. Its expression appears to be activated during pro-B-cell development, is abundant at the pre-B- and mature B-cell stages, but is absent in terminally differentiated plasma cells. Moreover, BSAP is clearly a B-cell-specific transcription factor, as a wild-type but not a mutant TSAP-binding site of the sea urchin functions only in transfected B cells as an upstream promoter element. Competition experiments did not reveal any high-affinity binding site for BSAP in known regulatory regions of immunoglobulin and class II major histocompatibility (MHC) genes, suggesting that BSAP is a regulator of a different set of B-lymphoid-specific genes.

Animals↗
PubMed1989

The protein CDP, but not CP1, footprints on the CCAAT region of the gamma-globin gene in unfractionated B-cell extracts.

We have identified, by DNase I footprinting, six different factors that interact with the promoter of the human A gamma-globin gene in nuclear extracts of the B-cell line BJA-B. Among them is the vertebrate homologue of the sea-urchin CCAAT displacement protein (CDP) which footprints over the entire duplicated CCAAT region. The CCAAT-binding factor CP1, a potential activator of the gamma-globin promoter, is able to bind to its proximal recognition sequence only once it has been partially enriched and separated from CDP. The factor CDP has an apparent molecular mass of 200 kDa and differs from CP1 by its footprint pattern and competition behavior.

B-Lymphocytes↗
PubMed1989

Developmental and tissue-specific regulation of a novel transcription factor of the sea urchin.

We have identified a novel transcription factor that interacts with the promoter of four tissue-specific late histone H2A-2 and H2B-2 genes of the sea urchin by DNase I footprint, mobility shift, and methylation interference analyses. The binding site for this factor is required for efficient transcription of the H2B-2.1 gene both in vitro in nuclear extracts of gastrula embryos and in vivo in microinjected sea urchin embryos. This factor binds with equal affinity to the recognition sequences of all four histone genes in cross-competition assays. Moreover, the binding site of the H2B-2.2 promoter can functionally substitute for that of the H2B-2.1 gene in in vivo expression experiments. Nevertheless, all four binding sites share little sequence homology with each other. This transcription factor increases in abundance during embryogenesis and has been detected in the adult sea urchin only in the tube feet, where the late H2A-2 and H2B-2 genes are expressed specifically. Therefore, we refer to this factor as tissue-specific activator protein (TSAP). The close correlation between the presence of TSAP and the expression pattern of the late H2A-2 and H2B-2 genes suggests that this transcription factor is directly responsible for the developmental and tissue-specific regulation of these genes.

Aging↗
PubMed1988

The -117 mutation in Greek HPFH affects the binding of three nuclear factors to the CCAAT region of the gamma-globin gene.

The Greek form of hereditary persistence of fetal hemoglobin (HPFH) is associated with a point mutation immediately upstream of the distal of the two CCAAT elements of the A gamma-globin gene. Three proteins present in nuclear extracts of erythroleukemia cells bind to this CCAAT region and contact the nucleotide mutated in Greek HPFH. The ubiquitous CCAAT-binding factor CP1 interacts preferentially with the proximal CCAAT sequence. An erythroid cell-specific factor, referred to as NF-E, binds with a higher affinity to the distal CCAAT region and interacts only with sequences flanking the CCAAT motif. The third protein is the vertebrate homologue of the sea urchin CCAAT displacement protein and recognizes sequences in both CCAAT elements and their flanking sequences. While the point mutation in Greek HPFH slightly strengthens the binding of CP1 and the CCAAT displacement protein, the same base change strongly reduces the binding of NF-E to the distal CCAAT region, suggesting a possible role of NF-E in the repression of gamma-globin genes in adult erythroid cells.

Base Sequence↗
PubMed1987

Mutually exclusive interaction of the CCAAT-binding factor and of a displacement protein with overlapping sequences of a histone gene promoter.

The sperm histone H2B-1 gene of the sea urchin Psammechinus miliaris contains two octamer sequences (ATTTGCAT) and two CCAAT motifs upstream of its TATA box. The CCAAT-binding factors present in nuclear extracts from testis and from blastula and gastrula embryos are indistinguishable by mobility shift and methylation interference analysis. However, there is a testis-specific octamer-binding factor in addition to the ubiquitous form. In DNAase I protection experiments, the CCAAT-binding factor of only the testis extract is able to interact with the sperm H2B promoter. In the two embryonic extracts a novel factor binds with high affinity to sequences overlapping the proximal CCAAT element, thus preventing the DNA interaction of the CCAAT-binding factor in the embryo where the sperm H2B gene is not expressed. This CCAAT displacement protein may therefore act as a repressor of sperm H2B gene transcription.

Base Sequence↗
PubMed1987

Long term treatment with oral single administration of bromocriptine in patients with hyperprolactinemia.

In the treatment of hyperprolactinemia bromocriptine is generally administered in 3 daily doses during the day. Due to the limited compliance of patients under this long term regimen, in 16 hyperprolactinemic patients we investigated the efficacy and tolerability of the treatment with this dopaminergic drug administered as a single evening dose. This dose was the same which the patients had been assuming previously on a tid basis. Chronic treatment (4-12 months) with an oral single evening dose of bromocriptine is able to control plasma PRL at least as well as the traditional tid regimen (2.8-21.6 ng/ml vs 1.2-31.8 ng/ml). Furthermore, during this single dose regimen the side effects were of lesser intensity and extent. Since the compliance of the patients with the single dose regimen was very good and the efficacy the same in reducing plasma PRL and controlling the clinical manifestations with a lower rate of side effects, we suggest to extend this regimen to all patients with hyperprolactinemia treated with bromocriptine after successful reduction of plasma PRL levels is obtained.

Administration, Oral↗
PubMed1985

Synthesis of sperm and late histone cDNAs of the sea urchin with a primer complementary to the conserved 3' terminal palindrome: evidence for tissue-specific and more general histone gene variants.

We have cloned histone cDNAs from total RNA isolated from testis and from gastrula-stage embryos of the sea urchin Psammechinus miliaris. The reverse transcription of histone mRNAs was specifically primed with an oligonucleotide that is complementary to the conserved palindromic sequence present at the 3' end of nonpolyadenylated histone mRNAs. Two sperm H2B, two late H2B, and three late H2A variant cDNA clones were isolated and characterized by DNA sequence analysis. These cDNA clones were used to study the accumulation of histone mRNA during sea urchin embryogenesis. The different late H2A and H2B mRNAs are present in as few as 200 copies in the egg and each accumulate to 3-5 X 10(5) molecules in the gastrula embryo. One of the late mRNAs, the H2A-3 mRNA, is also abundant in testis RNA and codes for the H2A variant present in sperm chromatin. The late H2A-3 protein is therefore a more prevalent H2A variant of the sea urchin. In contrast, the two sperm H2B mRNAs are found in testes but not ovaries and embryos of the sea urchin, suggesting that the sperm H2B genes are expressed only during spermatogenesis. In addition, evidence for gene conversion between two late H2A gene variants is presented.

Animals↗
PubMedDate not supplied

Seizures during concomitant treatment with theophylline and ranitidine: a case report.

H2-antagonists such as cimetidine and ranitidine are metabolized by cytochrome P-450. In this way they may interfere with theophylline metabolism. Cimetidine is known to have this effect and frequently to induce a theophylline toxic effect, while data concerning ranitidine are more uncertain. In this paper, we report the case of a 67-year-old woman with non-insulin dependent diabetes. She was taking aminophylline for respiratory failure and after ranitidine infusion exhibited generalized convulsions. Theophylline values which were monitored within the therapeutic range, increased toxic levels after ranitidine therapy and epileptic episodes. The increase in theophylline levels was associated with a further reduction in the clearance rate of the bronchodilator. We think that ranitidine may combine with other clinical factors known to reduce theophylline metabolism mainly in the elderly and severely ill patients. Theophylline-induced seizures may occur when theophylline serum levels are slightly above the therapeutic range, as in our case report.

Aged↗