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Biomedical subjects

B Dastugue

Publications and source records attributed to B Dastugue.

At least 73 records · Page 4Linked to original sources
PubMed1989

20-OH-ecdysone regulates 60 C beta tubulin gene expression in Kc cells and during Drosophila development.

Cultured Kc cells of Drosophila melanogaster are sensitive to the insect moulting hormone, 20-hydroxy-ecdysone (20-OH-E). Morphological changes of Kc-treated cells were observed and electron microscopic analysis of pseudopodia shows a large increase in the number of microtubules, all arranged in the same orientation. The 60 C beta tubulin gene which is expressed only in 20-OH-E-treated cells encodes a 2.6-kb mRNA which is essentially cytoplasmic and polyadenylated. The corresponding premessenger is 7 kb in length and is absent in untreated cells. Two peaks of expression of the 60 C beta tubulin gene are observed during Drosophila development: at midembryogenesis (stage 8-13 h) and at the late third instar larvae-early pupae stage. By use of the Ecdysone 1 mutant, 60 C beta tubulin gene expression was demonstrated to be regulated in part by 20-OH-E during Drosophila development. Through these two complementary biological models of study, the mode and role of beta tubulin gene regulation are discussed.

Animals↗
PubMed1989

[Prenatal diagnosis of X-linked adrenal hypoplasia associated with glycerol kinase deficiency].

We report a case of X-linked adrenal hypoplasia associated with glycerol kinase deficiency in a boy. Cytogenetic studies and X-linked probes did not demonstrate deletion at Xp21. These probes are not informative enough to be used in prenatal diagnosis. This diagnosis was achieved by glycerol concentration assay in amniotic fluid and by maternal plasma estriol assay.

Adrenal Glands↗
PubMed1988

Serum neuron-specific/nonneuronal enolase ratio in the diagnosis of neuroblastomas.

Pretreatment samples from 24 children with neuroectodermal tumors (two ganglioneuromas, 22 neuroblastomas) and from 106 others with various tumors were submitted to the enzymatic determination of the serum neuron-specific enolase (NSE). The enzymatic procedure employed in this study allows the systematic determination of the NSE and of the nonneuronal enolase (NNE), thus permitting the calculation of the ratio of the two enolase components. Like results obtained with other procedures, enzymatic determined serum NSE results were raised in a high proportion of Stage IV neuroblastoma (100%) but elevated values also were found in a considerable number of the other tumors (29.2%) like Wilms' tumor, lymphomas, and soft tissue sarcomas. The use of the NSE/NNE ratio which characterizes NSE elevations originating from relative poor or rich sources of NSE, represents an additional index for improving the specificity of the NSE results in the diagnosis of neuroblastomas. With a cutoff value fixed at 7.5%, the specificity of the test is 85.9%. When this limit is fixed at 15%, the specificity reaches 95.3% whereas 81.8% of the results of Stage IV neuroblastomas are still above this value.

Child↗
PubMed1988

20-Hydroxyecdysone induces the expression of one beta-tubulin gene in Drosophila Kc cells.

The expression of 56D and 60C beta-tubulin genes has been examined in Drosophila melanogaster Kc cells in response to the insect moulting hormone, 20-hydroxyecdysone (20-OH-E). Northern blots probed with beta-tubulin subclones show that the 56D beta-tubulin gene encodes a 1.8 kb mRNA whose abundance is not affected by 20-OH-E. The 60C gene probe detects two mRNAs: one of 1.8 kb present in untreated and 20-OH-E-treated cells, and one of 2.6 kb present only in 20-OH-E-treated cells; using a 60C 3'-specific probe, only the 2.6 kb is revealed. Hybrid selection translation experiment demonstrates that a 20-OH-E-inducible mRNA homologous to the 60C gene encodes a beta-tubulin subunit (P4); this subunit is the so-called beta 3-tubulin. Translation of size-fractionated mRNA shows that the 20-OH-E-induced beta 3-tubulin subunit is encoded, in treated cells, by the 2.6 kb mRNA.

Animals↗
PubMed1988

Molecular study of the retrovirus-like transposable element 412, a 20-OH ecdysone responsive repetitive sequence in Drosophila cultured cells.

Used at a physiological concentration, the steroid hormone 20-hydroxyecdysone (20-OHE) induces, in Kc cultured Drosophila melanogaster cells, important and specific changes. Modifications occur at morphological and enzymatical levels. Variations in specific protein synthesis are observed. At the molecular level, 20-OHE particularly induces a decrease in expression of the mobile dispersed genetic element 412. This repeated element which belongs to the "copia-like" family is more widely represented in Kc cells (80 fold) compared to fly cells (25 fold). 412 transcripts are heterogeneous in size, essentially polyadenylated and restricted to the nucleus. A minimal concentration of 10(-8) M and a time treatment of 16 hours are necessary to obtain a strong decrease in 412 expression. The decrease is at least an effect on these sequences at the transcriptional level. Structural similarities between the 412 element and the proviral forms of vertebrate retroviruses are strengthened by the characterization of extrachromosomal circular DNA forms revealed by the 412 probe. Quantifying experiments have shown that the steady state level of such forms is not affected by the steroid treatment.

Animals↗
PubMed1988

Preparation and purification of gamma gamma enolase (neuron-specific enolase) using high performance anion exchange chromatography.

A simple and rapid method, using only two chromatographic steps, is described for the purification and preparation of gamma gamma enolase isoenzymes from human and beef brain extracts. In the first step, a crude gamma gamma enolase was obtained by chromatography on Q-Sepharose Fast Flow column. The crude fraction was then purified by high performance anion exchange chromatography on a Mono-Q column. gamma gamma enolase obtained in this manner was shown to be homogeneous by two dimensional polyacrylamide gel electrophoresis and by high performance gel permeation chromatography. The yield of gamma gamma enolase by this method was 7-8 mg of pure enzyme per 100 g of brain.

Animals↗
PubMed1988

Enzymatic determination of serum neuron-specific enolase in small cell lung cancers. Utility of the serum neuron-specific enolase/serum nonneuronal enolase ratio.

Increasing interest is shown in the determination of the serum neuron-specific enolase for the diagnosis and the follow-up studies of small cell lung cancers. We report results obtained by an enzymatic procedure that permits the simultaneous determination of the neuron and nonneuron-specific enolase and the calculation of the ratio of these two components. The utility of this ratio which characterizes elevations of the serum neuron-specific enolase from a poor or rich source of this component was tested in 38 patients with small cell lung carcinoma and in 57 subjects suffering from other bronchogenic cancers. The control group consisted of 37 blood donors and 56 patients with respiratory disease. For the diagnosis, the sensitivity and the specificity of the enzymatically determined neuron-specific enolase compared well with published results obtained by radioimmunoassay and enzymoimmunoassay. The use of the ratio clearly increases the specificity of the test, since only 5.3 percent of false positive results are found when bronchogenic tumors other than small cell carcinoma are studied. The sensitivity was 76 and 100 percent in diagnosis of limited and extensive forms, respectively. The use of this ratio in the follow-up of the patients and for the determinations in hemolyzed samples is set out.

Adult↗
PubMed1988

Molecular biology diagnosis in oncology.

The applications of molecular biology diagnosis in oncology are presented and discussed. These are: improved nosologic definition; diagnosis of clonality; definition of new prognosis subgroups in some cancers; as an aid in bone marrow transplantation follow-up; diagnosis of the residual disease; early diagnosis of cancer; evaluation of individual cancer risk.

Bone Marrow Transplantation↗
PubMed1987

20-Hydroxyecdysone regulates cytoplasmic actin gene expression in Drosophila cultured cells.

The steroid hormone 20-hydroxyecdysone (20-OHE) induces, in Kc cultured Drosophila melanogaster cells, important morphological transformations and specific changes of enzymatic activities and of protein synthesis. These changes are accompanied by an increase of synthesis and an accumulation of actin. Specific probes were used to reveal transcripts of each actin gene in mRNA populations isolated from cells at various times of 20-OHE treatment. Only the two cytoplasmic actin genes 5C and 42A are expressed in Kc cells and the hormone induces the accumulation of transcripts of these two genes. We have also taken advantage of S1 mapping and extension procedures to identify the 5' ends of the actin mRNAs from these two genes and to compare their respective levels of expression. The 5C gene is more expressed than the 42A one in untreated and in hormone treated cells. The 5C gene encodes three RNAs that differ in their 3' end. The two genes are interrupted by an intervening sequence immediately upstream of ATG initiation codon but not at the same position. The transcription rate for the two genes is increased up to five fold upon 20-OHE treatment, demonstrating a direct effect of the steroid hormone at the transcriptional level for these genes.

Actins↗
PubMed1987

Interference by platelets in the electrophoretic determination of enolase isoenzymes in plasma.

Serum and plasma gave different electrophoretic patterns when enolase isoenzymes were evaluated by electrophoresis on cellulose acetate. Plasma isoenzyme bands were more intense, and there was an additional one (band P) that was not present in serum. We show that, under the conditions of electrophoresis, some of the residual platelets in the plasma are ruptured, releasing intracellular enolases and consequently leading to intensification of the isoenzyme bands. The band P originated from the remaining unruptured platelets. Thus plasma samples must be platelet-free for determination of enolase isoenzyme to be reliable.

Blood Platelets↗
PubMed1986

Determination of serum neuron-specific enolase by differential immunocapture.

A new method for the determination of serum neuron-specific enolase is presented. It consists of two steps: first, an immunocapture of gamma-subunit containing isoenzymes by absorption on immobilized anti-gamma antibodies; second, bioluminescence assay of enolase activities in untreated control samples and in the supernates of antibody treated samples. Total and alpha alpha activities are obtained, from which the neuron-specific enolase activity (alpha gamma + gamma gamma) can then be calculated by difference. As compared to the procedures currently in use, the immunocapture method is very rapid (30 min) and is more suitable for small series of determinations as needed in clinical chemistry applications. Reference interval values for serum found by this method agree with published data. When tested with samples from patients suffering from neuroblastoma or small cell lung cancer, it confirms the specific elevations in neuron-specific enolase activity previously described for these cancers, using other analytical approaches.

Adult↗
PubMed1986

Expression of a new beta tubulin subunit is induced by 20-hydroxyecdysone in Drosophila cultured cells.

One polypeptide, P4, of molecular weight 55000 daltons and pHi, 5,1, is synthesized in Drosophila melanogaster Kc 0% cells only when they were treated by the insect moulting hormone, 20 hydroxyecdysone (20-HE). P4 is precipitated with vinblastine sulfate and migrates as a tubulin subunit. Immunoblot experiment confirms that P4 is a beta subunit of tubulin. This beta tubulin is recovered by in vitro translation only when mRNAs are extracted from treated cells. Thus, regulation of expression of this polypeptide is at the level of transcripts and is under a steroid hormone control. The 20-HE induced beta tubulin comigrates with the beta 3 subunit and like the latter, is specific to the mid period of embryogenesis.

Animals↗