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G Simonin

Publications and source records attributed to G Simonin.

At least 19 recordsLinked to original sources
PubMed1999

[Precocious puberty secondary to an intramedullary germinoma].

BACKGROUND: hCG secreting tumors are responsible for 21% of precocious puberties in boys. Usual localizations are hepatic, cerebral, mediastinal and gonadic. CASE REPORT: A 4-year-old boy developed precocious puberty with rapid evolution. Serum beta hCG suggested germinal etiology, but radiological procedures failed to find any usual localization. Further occurrence of pain in the legs led to carry out a lumbar puncture. The high cerebrospinal fluid/blood gradient of beta hCG suggested the presence of an intramedullar tumor. Medullar magnetic resonance imaging found a large tumor facing L1 and L2. CONCLUSION: To our knowledge, this localization is described for only the second time.

Cerebrospinal Fluid↗
PubMed1999

Relationship between HLA-DQ and -DR genotypes and clinical characteristics in a French population of Type 1 diabetic patients.

AIMS: The present study was designed to look for a heterogeneity in the association between Type 1 diabetes mellitus (DM) and class II alleles of major histocompatibility complex (MHC) according to clinical presentation and C-peptide secretion during the first year of the disease, in a population living in south of France. METHODS: HLA DRB1 and DQB1 genotypes were determined in 129 Caucasoid patients with Type 1 DM and compared to a control group (n = 88). In a subgroup of 46 young adult diabetic patients, basal and postglucagon C-peptide secretion was followed during the first year of the disease (at 0, 1, 3, 6, 9 and 12 months). RESULTS: The two main haplotypes associated with Type 1 DM were DRB1*04DQB1*0302 and DRB1*03DQB1*02. The genotypes DRB1* 04DQB1 *0302/DRB1*04DQB1*0302 and DRB1 *03DQB1*02/DRB1*04DQB1* 0302 were associated with an early onset of diabetes, while homozygosity for DRB1*03DQB1*02 was characterized by later onset. Levels of residual insulin secretion in patients genotyped DRB1*03DQA1*0501DQB1* 02/DRB1* 04DQA1*0301DQB1*0302 were higher than in patients genotyped DRB1* 3DQA1*0501DQB1*02/DRB1*XDQA1*XDQB1*X or DRB1* XDQA1* XDQB1*X/DRB1*XDQA1*XDQB1*X. CONCLUSIONS: This study confirms some clinical heterogeneity of Type 1 DM linked to HLA DR and DQ genotypes, and leads to a paradoxical finding: DQB1*02/ DQB1*0302 combination predisposes to an early onset in the whole population but residual secretion of insulin disappears more slowly in a subgroup of young adults with recently diagnosed diabetes. These data suggest that interrelations between MHC genotype and diabetogenic process could be different at various ages of life.

Adolescent↗
PubMed1998

Pgp and MRP activities using calcein-AM are prognostic factors in adult acute myeloid leukemia patients.

Thirteen cell lines with different levels of Pgp and MRP expression were used to assess the ability of calcein acetoxymethyl ester (calcein-AM) uptake and calcein efflux to measure Pgp and MRP functions, respectively. There was a good correlation between MRP expression and the modulatory effect of probenecid (a specific modulator of MRP) on the calcein efflux (r = .91, P = .0003) and between Pgp expression and the modulatory effect of CsA on calcein-AM uptake (r = .96, P < .0001). In light of the high correlations for both proteins, we tested calcein-AM uptake and efflux in fresh myeloid leukemic cells. In 53 acute myeloid leukemia (AML) patients, there was also a good correlation between MRP expression (measured by reverse transcription-polymerase chain reaction and by MRPm6 expression by flow cytometry) and the modulatory effect of probenecid on the calcein fluorescence (r = .92, P < .0001) and between Pgp expression as measured by UIC2 antibody binding on flow cytometry and the modulatory effect of cyclosporin A on calcein-AM uptake (r = .83, P < .0001). Pgp activity was higher in CD34+ leukemia than in CD34- leukemia (2.26 +/- 1.50 v 1.46 +/- 1.21, respectively; P = .003), and MRP activity was higher in CD34- leukemia than in CD34+ leukemia (1.77 +/- 0.40 v 1.4 +/- 0. 29, respectively; P = .004). Pgp expression and activity (P = .004 and P = .01, respectively) and MRP activity (P = .03) but not MRP expression were prognostic factors for achievement of complete remission. These results suggest that functional testing (with calcein-AM +/- modulators) for the presence of both MRP and Pgp activities is of prognostic value and that MRP contributes to drug resistance in AML.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1998

Expression of genes implicated in multidrug resistance in acute lymphoblastic leukemia in India.

In order to investigate the phenomenon of multidrug resistance as a possible mechanism for poor response to treatment in patients with acute lymphoblastic leukemia (ALL) from India, a series of 32 cases of de novo untreated ALLs were analyzed by a cDNA-PCR approach to estimate the relative mRNA levels of the MDR-associated genes encoding MDR1, MRP, GSTpi, and GSTmu. The expression of beta2 microglobulin served as an internal standard. Quantifiable transcripts were observed in 20 patients for MRP, in 5 for MDR1, in 24 for GSTpi, and in 19 for GSTmu. The values ranged from undetectable to 132% of the control A549 cell line for MRP, undetectable to 49% of the HL60/DNR control cell line for MDR1, undetectable to 268% of A549 control cell line for GSTpi, and undetectable to 247% of A549 control cell line for GSTmu mRNA. Increased MRP levels were associated with increased GSTpi and GSTmu levels (p<0.01 for both), and increased levels of MDR1 were associated with increased GSTpi levels (p<0.05). The present observations showed no correlation between the MDR1 and MRP values with treatment outcome, in terms of either achieving a complete remission or predilection to early relapse. In view of some recent studies that envisage MRP as an energy-dependent pump involved in the efflux of GSH conjugates, the simultaneous up-regulation of transcription of all these genes might well be part of an integrated detoxification response that has been switched on after exposure to an environmental stress.

ATP-Binding Cassette Transporters↗
PubMed1998

Lung resistance protein (LRP) gene expression in adult acute myeloid leukemia: a critical evaluation by three techniques.

The role of LRP in clinical drug resistance in acute myeloid leukemia (AML) is controversial. We therefore compared multiple assays, including RT-PCR, immunocytochemistry (ICC) and flow cytometry (FC), in 10 cell lines and in 47 fresh and thawed AML cells in order to validate and to quantitate measures for LRP phenotype detection. We also compared different ways of expressing the results. Lastly, in cell lines, we analyzed the 50% lethal concentration (LC50), by MTT assay, of cisplatin which could estimate the functionality of LRP. The reproducibility of LRP detection measured by RT-PCR, ICC and FC was good. In the same way, within the same technique, there was good correlation between the different methods of expressing the results of LRP level. Therefore, the discrepancies noted with the three techniques used were neither a problem of reproducibility nor a problem of results expression. On the other hand, there was only a correlation between ICC and FC, and no correlation between RT-PCR and LRP protein detection techniques. Therefore, RT-PCR is probably not the optimal technique for LRP detection. We have shown in 10 cell lines a higher correlation between FC and LC50 of cisplatin than between ICC and LC50 of cisplatin and no correlation between RT-PCR and LC50 of cisplatin. For five patients, there was a dissociation between ICC and FC. Four patients were positive by FC and negative by ICC and only one patient was negative by FC and positive by ICC. Therefore, if in vitro resistance to cisplatin represents the functionality of LRP, we recommend the use of FC rather than ICC to detect LRP expression. Besides the measurement of LRP as a diagnostic tool in the evaluation of resistance to chemotherapy in patients with AML, we urgently need to establish a functional test in order to assess LRP activity.

Acute Disease↗
PubMed1998

Adult biphenotypic acute leukaemia: an entity with poor prognosis which is related to unfavourable cytogenetics and P-glycoprotein over-expression.

Biphenotypic acute leukaemia (BAL) patients represented 8% of the 287 de novo consecutive adult acute leukaemias (23 BAL, 230 acute myeloid leukaemia (AML) and 34 acute lymphoblastic leukaemia (ALL)) referred to our department during the last 4-year period. Of these 23 BAL patients, 14 patients showed myeloid morphology and nine cases lymphoid morphology according to FAB criteria. There were no differences between lymphoid and myeloid BAL according to clinical and biological presentation and treatment outcome. We confirm the poor prognosis of BAL when compared to AML or ALL seen during the same period of time, in terms of complete remission (47%, 62% and 82% respectively, BAL v AML, NS and BAL v ALL, P = 0.006) and 4-year overall survival (8.1%, 25.8% and 23.8% respectively, BAL v AML, P = 0.05 and BAL v ALL, P = 0.003). Comparing adult BAL patients with AML patients, we found an increase in poor prognostic factors: CD34+ phenotype (82% v 60% respectively, P = 0.03), unfavourable karyotype (60% v 20%, P < 0.0001) and Pgp over-expression by RT-PCR (0.705 v 0.107, P < 0.0001) and flow cytometry (0.824 v 0.391, P = 0.0001). MRP and LRP were not found to be poor prognostic factors. Comparing BAL patients with ALL patients, we found also an increase in poor prognostic factors: age (51 v 39, P = 0.003) and CD34+ phenotype (82% v 50%, P = 0.02). We conclude that BAL patients need a more aggressive treatment procedure, including high-dose AraC or the use of Pgp modulators for first-line therapy.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1997

Effect of the multidrug inhibitor GG918 on drug sensitivity of human leukemic cells.

The drug GG918 has been specifically developed for overcoming MDR phenotype and is now in use in clinical trials. In this study, the effects of GG918 on leukemic cell were investigated using a 3 day MTT assay. Results showed that, in a highly resistant P-gp(+) leukemic cell line, 0.1 microM of GG918 gives rise to a 40-fold sensitization to daunorubicin (DNR) (residual resistance: 2.1), a 57-fold sensitization to mitoxantrone (residual resistance: 1.5), and a 3.3-fold sensitization to idarubicin (residual resistance: 2.9). When human AB serum was added to the incubation medium, 1 microM of GG918 was needed to observe the full P-gp modulation potency described above. The effect of 1 microM of GG918 was tested on 27 samples of poor prognosis acute leukemia (25 AML, two ALL). DNR sensitization (using the MTT assay) and modulation of rhodamine 123 uptake were monitored and used as criteria for comparing the in vitro modulation potency of this new compound to the potency of 10 microM of verapamil, which was used as reference. A good correlation (r = 0.8, P = 0.001) was observed between the results of the two tests. Eleven out of the 26 cases tested were MDR1(+) (42%), and showed a higher IC50 for DNR than the negative cases (861 +/- 1284 nM vs 187 +/- 246 nM, P = 0.05). GG918 was able to modulate the in vitro resistance to DNR in eight cases (seven MDR1(+), no MDR1(-), one non-tested). Verapamil did not increase DNR toxicity in four of these eight cases, but was more efficient in one other MDR1(+) case. In conclusion, the DNR sensitivity of the majority of the fresh AML samples expressing P-gp could be modulated in vitro by 1 microM of GG918.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1997

Late effects of allogeneic bone marrow transplantation for children with acute myeloblastic leukemia in first complete remission: the impact of conditioning regimen without total-body irradiation--a report from the Société Française de Greffe de Moelle.

PURPOSE: To evaluate growth, thyroid function, puberty, cardiac function, and the incidence of cataracts in children who received allogeneic bone marrow transplantation (BMT) for acute myeloblastic leukemia (AML) in first complete remission (CR) after a preparation with or without total-body irradiation (TBI). PATIENTS AND METHODS: Among 45 children studied, 26 received busulfan-cyclophosphamide (Bu-Cy) in preparation for transplantation and 19 received TBI. TBI was fractionated in nine cases and delivered as a single dose in 10. Four children in the Bu-Cy group and none in the TBI group had received prior cranial radiation. The mean follow-up duration after BMT was 5.9 years for the whole group. RESULTS: The mean cumulative changes in height SD score (SDS) were -0.86 at 3 years and -1.56 at 5 years in the TBI group, whereas these changes were only -0.05 and -0.17 in the Bu-Cy group (P < .01 at 3 and 5 years). The 6-year probability of hypothyroidism was 9% +/- 8% in the Bu-Cy group and 43% +/- 15% after TBI (P < .02). Pubertal development after Bu-Cy was assessable in two girls and five boys: both girls had primary ovarian failure, whereas Leydig cell function appeared to be preserved in the five boys. One child who had received anthracycline when he was less than 1 year old developed cardiac dysfunction 4 years after Bu-Cy. The 6-year probability of cataracts was 70% +/- 13% in the TBI group and 0% after Bu-Cy. CONCLUSION: The use of Bu-Cy represents an alternative transplant cytoreductive regimen for children with AML in first CR, which can reduce the risk of posttransplant growth impairment, thyroid dysfunction, Leydig cell damage, and the incidence of cataracts.

Adolescent↗
PubMed1996

Expression of the multidrug resistance-associated protein (MRP) mRNA and protein in normal peripheral blood and bone marrow haemopoietic cells.

We studied the expression of multidrug resistance-associated protein (MRP) in normal haemopoietic cells from peripheral blood and bone marrow. The MRP mRNA levels were estimated by RT/PCR and in situ hybridization (ISH) assay, and the protein levels by flow cytometry. 21 samples of peripheral blood and 21 samples of bone marrow (11 normal bone marrow donors, 10 patients in complete remission after chemotherapy for large cell lymphoma or acute myeloid leukaemia) were analysed. In peripheral blood the mean MRP mRNA level in CD3+ cells was statistically higher than in the other cells (3-fold by the methods used). The levels of MRP in CD3+ varied from one individual to another (4.5-34.8 units by RT/PCR and 5-23 grains/cell by ISH); however, this was proportional to the variation in all the cell lineages of same individual (r = 0.84). In bone marrow the mean MRP levels of the various cell lineages (including CD34+) were similar to the basal level in HL60 cells. Individual expression levels were again variable; however, there was no difference between untreated normal bone marrow and post chemotherapy normal bone marrow. MRP protein expression was determined by flow cytometry with the monoclonal antibody MRPm6. The CD4+ lymphocytes exhibited a higher MRP protein expression than the other cell lineages, including CD8+ cells. There was a good correlation between the three methods used (RT/PCR and ISH, P = 0.0001, r = 0.87; RT/PCR and flow cytometry, P = 0.0001, r = 0.85; ISH and flow cytometry, P = 0.002, r = 0.67).

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1995

Glutathione-S-transferases pi, alpha, mu and mdr1 mRNA expression in normal lymphocytes and chronic lymphocytic leukemia.

Chronic B cell lymphoproliferative disorders are frequently sensitive to alkylating agents. To assess the glutathione-S-transferases (GSTs) gene expression in B tumoral lymphocytes, possibly responsible for this sensitivity, we developed a sensitive RT-PCR assay for the three isoenzymes GST pi, GST mu and GST alpha mRNA. Normal B and T lymphocytes from 11 blood donors were separated by magnetic beads and tested with this assay. The GST pi was the most abundant transferase, and was detected in all B and T cell samples. GST mu was undetectable ('null' phenotype) in 6/11 normal donors, either in B or T cells. GST alpha was very stable from donor to donor, and was highly correlated between B and T cells of the same individual (P < 0.0001). There is no correlation between the three isoenzymes, and between each isoenzyme and mdr1 gene expression. Twenty-three B lymphoproliferative disorders (20 B-CLL, 3 CD5- chronic lymphoproliferative syndromes) were tested with the same technique. An average decrease of 57% of the GST pi expression was noted in the mononuclear cells of these patients (P < 0.02), with no differences between the untreated and treated cases. The GST alpha and mdr1 mRNA levels did not differ from normal B lymphocytes, but the proportion of patients with no detectable expression of GST mu is lower than in the control (13%). Interestingly, the low content of GST pi in B-CLL could explain the frequent sensitivity of this disease to alkylating agents.

Adult↗
PubMed1994

Cytoplasmic sequences of the growth hormone receptor necessary for signal transduction.

To study structure-function relationships of the growth hormone (GH) receptor (GHR), two functional systems have been developed. CHO cells were transiently cotransfected with the cDNA encoding the full-length rat GHR and with a construct consisting of the 5' flanking region of one of two GH-dependent genes encoding ovine beta-lactoglobulin or serine protease inhibitor 2.1 (Spi 2.1, formerly Spi.1; the corresponding rat gene has recently been redesignated Spin2a) coupled to the bacterial reporter gene encoding chloramphenicol acetyltransferase (CAT). Transfected cells were grown in the absence and presence of human GH and dexamethasone for the Spi 2.1 gene construct. GH was able to activate each promoter (with approximately 4-fold induction of CAT activity) in a dose-dependent manner. For both tests, the maximal effect was observed at 20 nM human GH. These tests have been used to identify functional domains of the GHR. Two truncated (T) GHRs, lacking most or part of the cytoplasmic domain [called T276 (ending at residue 276) and T436 (ending at residue 436)], were unable to stimulate CAT activity. The GHR contains a proline-rich region, called "Box I," conserved in the cytokine/GH/prolactin receptor family. Alanine substitutions for the four prolines of GHR Box I were introduced. Single proline-to-alanine mutations did not affect the functional activity of the GHR. However, modification of the four prolines together or deletion of the Box I (15 amino acids between positions 279 and 293) resulted in the complete absence of GH stimulation. Thus, the proline-rich region, shown to be important for other members of this receptor superfamily, is also critical for GH signal transduction.

Amino Acid Sequence↗
PubMed1994

Tolfenamic acid and mefenamic acid in the treatment of primary dysmenorrhoea.

The clinical efficacy of tolfenamic acid and mefenamic acid in the treatment of primary dysmenorrhoea was studied in a prospective, controlled, double-blind, cross-over study comprising 73 patients aged 13-39 with an average body weight of 56 kilos. The patients were randomized to receive either tolfenamic acid (200 mg t.i.d.) or mefenamic acid (500 mg t.i.d.) for 3 days, during 3 consecutive menstrual cycles each, in a sequential design A-B or B-A. At the beginning and at the end of each treatment period, 13 dysmenorrhoeic symptoms were evaluated on a visual analogue scale (lower back pain, interference with daily activities, nausea, vomiting, diarrhoea, headache, dizziness, fatigue, sweating, chills, hot flashes, depressant states, and mood swings). The data were analyzed by using two statistical models. The first one, for the 73 patients, by making paired comparisons regardless of treatment sequence. With respect to the initial values, the results showed that both drugs were statistically significant (P < 0.05) in reducing the intensity of the evaluated symptoms. When comparing both treatments, tolfenamic acid showed a significant difference as to interference with daily activities (P < 0.025) and hot flashes (P < 0.005). In the result analysis with the second model, the groups were divided according to the first assigned treatment and paired comparisons were made. It was observed that the group receiving tolfenamic acid in the last sequence reached a higher level of response and statistical significance was demonstrated in 8 of 13 evaluated symptoms.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1994

Study of final height in Turner's syndrome: ethnic and genetic influences.

In understanding Turner's syndrome, spontaneous adult height is a prerequisite for an accurate assessment of the therapeutic efficiency of growth hormone treatment. The heights described in the literature reveal significant differences (136-147 cm). Our collaborative study pooled results from 16 pediatric endocrinology centers and obtained a large number of spontaneous adult heights (n = 216). The selective criteria were: chronological age (CA) > 18 years, bone age (BA) > 16 years, typical karyotype, no treatment with growth hormone or anabolic steroids. Mean CA was 23.3 +/- 5.6 years. Chromosomal anomalies were: monosomy X 56%; mosaicism 37.2%; structural aberration 10.6%. Mean final height in the whole group was 141.5 (129-160) cm. There was no significant difference in height between the three groups: monosomy X (n = 121: 141.1 +/- 6.4 cm); mosaicism (n = 72: 141.5 +/- 7.5 cm); X anomaly (n = 23: 141.4 +/- 5.0 cm). Mean parental height was 170.4 +/- 7.1 cm (father) and 160.1 +/- 6.2 cm (mother). Parental height and patients' heights correlated significantly, but more so with fathers' heights (r = 0.50) than with mothers' (r = 0.42). The correlation was still apparent with the target height (r = 0.55). The results of different series in the literature show the existence of significant variations as mean final heights are between 136 and 147 cm. These differences can be explained by the variations in normal female heights in each country. We have found in these different countries a very strong correlation (r = 0.91) between normal height and final height in Turner's syndrome.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1993

Evidence for generation of the growth hormone-binding protein through proteolysis of the growth hormone membrane receptor.

The growth hormone-binding protein (GHBP) which circulates in plasma is a soluble short form of the membrane growth hormone receptor (GHR). In rats and mice, GHR and GHBP originate from two alternatively spliced mRNAs (4.5 and 1.2 kb). In human and rabbit tissues, a single predominant mRNA of 4.5 kb was detected and it was hypothesized that GHBP could be produced by proteolytic cleavage of the GHR. Using gel filtration and HPLC, we have detected a high level of GH binding activity in media of cells transfected with rabbit GHR cDNA. The [125I]hGH-GHBP complex eluted at the same time as the plasma complex and both the binding affinity and specificity of the BP were comparable to that of rabbit plasma. Immunoprecipitation experiments and Western blots confirmed that GHBP in the media of transfected cells was a 55 kDa protein related to the extracellular domain of the GHR. In contrast, no BP was detected in the media of cells transfected with the cDNA encoding the rat GHR. These results strongly suggest that, in rabbit and probably in man, the GHBP could, at least in part, be produced by proteolytic cleavage of the GHR.

Animals↗
PubMed1993

[Klinefelter syndrome in 1993. Results of a multicenter study on 58 cases and review of the literature].

A retrospective multicenter study found 58 cases of Klinefelter syndrome of which 23 (39%) were diagnosed before puberty. Although as common as Down syndrome, Klinefelter syndrome is underdiagnosed and often recognized only in adulthood. Suggestive manifestations in infants, children, and teenagers include facial dysmorphism, micropenis, and delayed speech and should lead to examination of the karyotype. Early recognition of Klinefelter syndrome could be achieved by routinely measuring the size of the testes in school-boys aged 11 to 15 years and performing a karyotype in boys with a volume of less than 2 ml. Early psychological and educational support and testosterone replacement therapy initiated at onset of puberty may lead to improved social and academic outcomes.

Adolescent↗