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Biomedical subjects

F Picard

Publications and source records attributed to F Picard.

At least 91 records · Page 5Linked to original sources
PubMed1997

Fetal Rhesus D genotyping on amniocytes in alloimmunised pregnancies using fluorescence duplex polymerase chain reaction.

OBJECTIVE: 1. To establish the reliability of fetal amniocyte Rhesus D (RhD) genotyping using fluorescence duplex polymerase chain reaction (PCR) and 2. to assess the potential clinical impact on management of alloimmunised pregnancies. DESIGN: Multicentre observational study. SETTING: Four departments of obstetrics and gynaecology in Germany. METHODS: Fourty-four amniotic fluid samples were obtained by amniocentesis from a retrospective group of 27 RhD alloimmunised pregnancies and 15 samples from 14 women treated prospectively. Two RhD gene specific fragments (exon 7 and 10) were amplified using two separate fluorescence duplex PCR assays, and laser detected in an automated DNA sequence analyser. RESULTS: Amplification of the Rh gene sequences was successful in all samples. PCR at the two RhD gene regions resulted in complete concordance. Genotyping correctly predicted the RhD status of all fetuses serotyped (n = 41). After intrauterine transfusions, PCR identified the RhD type of two fetuses more accurately than serotyping. Earlier knowledge of a negative RhD status would have rendered unnecessary 12 amniocenteses in four fetuses of the retrospective study group, and prevented further invasive testing in one fetus treated prospectively. In the latter group, women with a positive fetal RhD genotype underwent intensive prenatal care including serial invasive monitoring and intrauterine treatment. CONCLUSIONS: Fetal RhD genotyping of amniocytes is a reliable technique with the potential to improve routine management of alloimmunised pregnant women.

Amniocentesis↗
PubMed1997

Reconstruction of the lateral ankle ligaments using an inferior extensor retinaculum flap.

The aim of this study was to assess the results of 32 cases of chronic ankle instability. These were treated by ligament shortening and reinforced with an inferior extensor retinaculum flap. All patients complained of persistent functional instability unrelieved with proprioceptive exercises. Results were assessed clinically (pain, instability, recovery of sports activity, mobility) and radiologically (correction of laxity on stress x-rays). This enabled us to draw up a revision score on a scale of 100 points. We obtained a mean score of 86.7 points (45-100 points), and subjective results showed that 88% of the patients were satisfied with the surgery.

Adolescent↗
PubMed1997

[A morphometric study of the femoro-patellar joint from lateral x-ray view].

PURPOSE OF THE STUDY: The goal of this study was to specify criteria of femoro-patellar joint normality on lateral view. MATERIAL: This study was based on radiological examination of 102 knees in 51 adults (average age 26.1 years). It concerned 29 women and 22 men that had never suffered from their knee and were supposed healthy. METHODS: The radiological protocol was the following: a lateral view at 45 degrees of flexion, two lateral views in extension, with and without quadriceps contraction. The analysis was focused on patellar surface aspect, its height, its depth and covering measurement. RESULTS: We found 83.7 per cent of so-called "normal" patellar surface, and 12.7 per cent of "abnormal" patellar surface (dysplasia) in the absence of pain. DISCUSSION: We have confirmed figures advanced in others series of the literature concerning patellar height and patellar surface, as well as patellar surface depth and covering. We have underlined the interest of lateral views; in extension with quadriceps contracted and relaxed. Finally, we have defined a trochleo-patellar sign that allows to correlate patellar height to patellar surface height (ITP = 0.35 to 0.84). CONCLUSION: This study insists on the interest of radiological lateral views of the knee and determine criteria for normalities.

Adult↗
PubMed1997

[Diurnal and nocturnal paroxysmal dyskinesia in young children: a new entity?].

Paroxysmal dyskinesias are intermittent attacks of involuntary hyperkinetics abnormal movements. Among paroxysmal dyskinesias were individualized three entities: paroxysmal kinesigenic choreoathetosis, paroxysmal choreoathetosis of Mount and Reback, hypnogenic paroxysmal dystonia. New classifications are based upon the circumstances of occurrence, the duration of attacks and their etiology. We report here two observations of idiopathic non familial paroxysmal dyskinesias in three-year-old children. Both were seen first in consultation for falls and nocturnal motor agitation. The attacks were paroxysmal jerky "puppet-like" movements lasting from 20 seconds to 15 minutes. They could occur during non REM sleep, during the day, at rest, after a sudden movement, or during prolonged exercise. Carbamazepine was inefficient. These cases were not classifiable according to the classical criteria and could constitute a new entity. Moreover, some sleep-EEG showed abnormal patterns (frontal rapid rhythms, central spikes in one case) and led us to discuss the pathophysiology of this episodic movements disorder, and its relation with frontal partial epilepsy.

Arousal↗
PubMed1996

Loss of primitive hematopoietic progenitors in patients with human immunodeficiency virus infection.

A number of hematologic abnormalities, including cytopenias, have been observed in patients with human immunodeficiency virus (HIV) infection. To elucidate their mechanisms, primitive cells from bone marrow aspirates of 21 patients with HIV-1 infection were quantitated by flow cytometry. The mean percentage of CD34+ cells is not significantly altered in HIV-1-infected patients in comparison with HIV-1-seronegative controls. In contrast, two- and three-color immunofluorescence analysis showed that in all HIV-1 samples, most CD34+ cells coexpressed the CD38 antigen. The proportion of HIV-1-derived CD34+ cells that did not express the CD38 antigen was significantly lower (HIV-1+: mean, 1.73%; controls: mean, 14%; P < .0005) than in controls. Moreover, of Thy-1+ cells, the proportion of CD34+ cells was twofold lower in HIV-1-infected patients (HIV-1+: mean, 12%; controls, 25%, P < .0005), which suggests that phenotypically primitive cells are depleted in HIV-1 infection. In vitro functional analysis in long-term cultures of sorted CD34+ cells from seven HIV-1 patients showed that CD34+ cells from HIV-1 patients generated much fewer colonies both in the nonadherent and adherent layers than CD34+ cells from controls after 5 weeks of culture (10-fold and four-fold less, respectively). Precise long-term culture initiating cell (LTC-IC) frequency in the CD34+ cell population was determined in three patients by limiting dilution and was markedly decreased in comparison to that of normal controls (from twofold to > sevenfold decreased). To determine if primitive cells were infected by HIV-1, both methylcellulose colonies generated from long-term culture of CD34+ cells and various CD34+ cell fractions purified by flow cytometry were evaluated for the presence of HIV-1 by polymerase chain reaction (PCR). Progeny from long-term culture was HIV-1-negative in three samples. In addition, using a sensitive PCR technique, the HIV-1 genome could not be detected in CD34+, CD34+/CD38-, and CD34+/CD4+ cells. These data show that hematologic disorders in HIV disease may be the consequence of a deficit of primitive cells. However, direct infection of these cells by HIV-1 does not seem to be responsible for this defect.

ADP-ribosyl Cyclase↗
PubMed1996

Ectopic expression of murine TPO receptor (c-mpl) in mice is pathogenic and induces erythroblastic proliferation.

c-mpl, the cellular homologue of the v-mpl oncogene transduced in the myeloproliferative leukemia virus (MPLV), encodes the receptor for thrombopoietin, a cytokine involved in the proliferation and differentiation of cells of the megakaryocytic lineage. Here, we show that a retrovirus containing murine c-mpl cDNA (HSFmmpl) is pathogenic in vivo when inoculated in adult mice. All mice developed hepatosplenomegaly and died within 9 to 12 weeks after infection. Histological analysis showed that spleen, liver, and peripheral blood were invaded by erythroblasts at every stage of differentiation. In contrast to the myeloproliferative syndrome induced by MPLV, we did not observe an infiltration of these organs with cells from the granulocytic lineage nor a thrombocytosis. In fact, the platelet count of HSFmmpl mice progressively decreased and a severe thrombocytopenia was observed late in the course of the disease. Further characterization of the target progenitor of HSFmmpl virus in the spleen and bone marrow of diseased animals was accomplished using in vitro clonogenic progenitor cell assays. This analysis indicated that both late and early erythroid compartment (colony-forming unit-erythroid and burst-forming unit-erythroid) were largely increased in the spleens. The colony-forming unit-granulocyte-macrophage compartment was also increased but to a lesser extent. This study shows for the first time that ectopic expression of a member of the cytokine receptor superfamily promotes hematopoietic progenitor cell proliferation and could play a role in leukemogenesis.

Animals↗
PubMed1996

Incidence and characterization of MLL gene (11q23) rearrangements in acute myeloid leukemia M1 and M5.

To determine the incidence of MLL rearrangement in acute myeloid leukemia (AML) French-American-British (FAB) type M1 and to evaluate optimal screening strategies for the characterization of such abnormalities, we analyzed specimens from 41 patients with AML by Southern blotting with two MLL genomic probes and compared the capacities of reverse transcription-polymerase chain reaction (RT-PCR) and fluorescent in situ hybridization (FISH) to identify the types of rearrangement found in AML M1 with those observed in AML M5. MLL rearrangement was found in 6 of 29 (20%) AML M1 and 6 of 10 AML M5 cases. RT-PCR characterization of 11 cases showed four MLL self-fusions, four MLL-AF6, two MLL-AF9, including a novel AF9 breakpoint, and one uncharacterized t(11:19). Only 5 of 10 MLL-rearranged cases tested demonstrated karyotypic 11q23 abnormalities. FISH analysis of nine cases with an MLL-specific yeast artificial chromosome (YAC) confirmed the cytogenetic abnormalities in two cases, clarified them in one, and did not detect six cases, including three MLL self-fusions, one case with a probable MLL-rearranged subclone not represented karyotypically, and twoMLL-AF6. A whole chromosome 11 paint detected one of these MLL-AF6, and an AF6 cosmid demonstrated that the other was probably due to insertion of a submicroscopic portion of chromosome 6, including part of AF6, into an apparently normal chromosome 11. We conclude that MLL rearrangements are common in adult AML M1, that MLL self-fusion and MLL-AF6 are the most frequent types of abnormalities, and that RT-PCR is preferable to 11q23 FISH analysis for their characterization.

Adult↗
PubMed1996

Frequent allele loss on 9p21-22 defines a smallest common region in the vicinity of the CDKN2 gene in sporadic breast cancer.

Genetic studies of chromosome arm 9p have indicated the presence of one or more tumor suppressor genes involved in genetic susceptibility to various types of human cancers. To define the extent of the specific deletion of 9p21-22 in human breast cancer, we have analyzed loss of heterozygosity and homozygous deletion of 9p21-22 in 68 paired blood and tumor samples by using fluorescent multiplex polymerase chain reaction (PCR). Of these tumors, 43% (29/68), including two ductal carcinomas in situ (DCIS), showed allele loss at one or more loci analyzed. Homozygous deletion for 9p markers was detected in 7/68 (10%) of tumor samples. Eleven tumors showed allele loss at all informative loci, and 18 tumors showed selective deletion on 9p21-22. Allele deletions in six tumors did not involve microsatellite markers flanking CDKN2. The smallest common region of deletion could be defined between D9S171 and D9S126. No significant associations were observed between deletion of 9p21-22 and any of the histopathological parameters analyzed. However, the abundance of deletions of this chromosomal region still suggests that loss and inactivation of putative tumor suppressor gene(s) located on 9p21-22 may be involved in the pathogenesis of breast cancer.

Alleles↗
PubMed1996

Postencephalitic stereotyped involuntary movements responsive to L-Dopa.

In 1954, at the age of 5 years, our patient had an encephalitic syndrome associated with a prolonged lethargic state. After this episode, he developed a severe parkinsonian syndrome that, after a few years, was associated with axial dystonia and stereotyped abnormal movements of the upper limbs. This complex and progressive extrapyramidal syndrome had many similarities to the encephalitis lethargica as described by von Economo. Results of cerebral computed tomography and magnetic resonance imaging were normal. Fluorodopa positron emission tomography showed a significant bilateral reduction of tracer accumulation in both putamen, similar to that observed in patients with idiopathic Parkinson's disease. However, in this patient, treatment with L-Dopa suppressed all akinetic, dystonic and dyskinetic symptoms. The effectiveness of L-Dopa was abolished by administration of a D2 antagonist and was fully reproduced by a D2 agonist. In conclusion, this patient presented a complex postencephalitic, extrapyramidal syndrome, with akinetic symptoms and involuntary movements. These symptoms appeared to be related to a limited lesion of the dopaminergic neurons of the zona compacta of the substantia nigra.

Adult↗
PubMed1996

Model of interaction between a cardiotoxin and dimyristoylphosphatidic acid bilayers determined by solid-state 31P NMR spectroscopy.

The interaction of cardiotoxin IIa, a small basic protein extracted from Naja mossambica mossambica venom, with dimyristoylphosphatidic acid (DMPA) membranes has been investigated by solid-state 31P nuclear magnetic resonance spectroscopy. Both the spectral lineshapes and transverse relaxation time values have been measured as a function of temperature for different lipid-to-protein molar ratios. The results indicate that the interaction of cardiotoxin with DMPA gives rise to the complete disappearance of the bilayer structure at a lipid-to-protein molar ratio of 5:1. However, a coexistence of the lamellar and isotropic phases is observed at higher lipid contents. In addition, the number of phospholipids interacting with cardiotoxin increases from about 5 at room temperature to approximately 15 at temperatures above the phase transition of the pure lipid. The isotropic structure appears to be a hydrophobic complex similar to an inverted micellar phase that can be extracted by a hydrophobic solvent. At a lipid-to-protein molar ratio of 40:1, the isotropic structure disappears at high temperature to give rise to a second anisotropic phase, which is most likely associated with the incorporation of the hydrophobic complex inside the bilayer.

Aniline Compounds↗
PubMed1996

Clinical impact of detection of loss of heterozygosity of BRCA1 and BRCA2 markers in sporadic breast cancer.

The development of familial and sporadic breast cancer is based on genetic alterations of tumour-suppressor genes, for which loss of heterozygosity (LOH) is one mechanism of gene inactivation. To investigate LOH of BRCA1 (17q21) and BRCA2 (13-q12-13) in sporadic breast cancer, polymerase chain reaction (PCR)-based fluorescent DNA technology for detection of microsatellite polymorphisms was applied. A total of 137 breast cancer and 15 benign breast specimens with matched normal tissue were examined. Fluorescent-labelled PCR products were analysed in an automated DNA sequencer (ALFTM Pharmacia). Losses at both loci were correlated with different histological types, age, tumour size, lymph node status, grading and steroid hormone receptor expression, [SHR: oestrogen receptor (ER), progesterone receptor (PgR)]. For BRCA1 (D17S855, THRA1, D17S579) losses could be detected in invasive ductal carcinoma (IDC; n = 108) in 32-38%, invasive lobular carcinoma (ILC; n = 19) in 21-42% depending on the marker applied, but not in benign breast tumours (n = 15). Losses of BRCA1 markers correlated with larger tumour size, higher grade, and PgR expression. For BRCA2 (D13S260, D13S267, D13S171) losses could be detected in 108 IDCs in 30-38%, in 19 ILCs in 17-39% depending on the marker applied, but not in benign breast tumours. Losses of BRCA2 markers correlated only with higher grade. Microsatellite analyses combined with detection of fluorescent-labelled PCR products by an automated laser DNA sequencer can be used for routine determination of LOH. In sporadic breast cancer, LOH of BRCA1 of BRCA2 does not add decisive prognostic value as stated for familial breast cancer.

Age Factors↗
PubMed1996

Postprandial serum lipids and tissue lipoprotein lipase are acutely altered in rats by the alpha-glucosidase inhibitor acarbose.

The purpose of this study was to evaluate the consequences of the acarbose-induced attenuation of postprandial glycemia and insulinemia on plasma lipid concentrations and on tissue lipoprotein lipase (LPL) activity. Rats were fed a high-sucrose diet ad libitum for two weeks. On the day of the experiment, half of the animals were given a high-sucrose meal, whereas the other half were given acarbose (10 mg/kg body weight) mixed with the meal. Serum lipids and tissue LPL activity were assessed in samples collected one hour after meal intake. Glycemia was comparable in both groups, whereas serum insulin in acarbose-fed rats was half that of control animals. The main effects of acarbose on postprandial lipids consisted of a lowering of triacylglycerols (-50%) and non-high density lipoprotein cholesterol. LPL was not altered by acarbose in white and brown adipose tissues, but was higher in the heart (+33%). The effects of acarbose on postprandial serum lipids are consistent with a slower rate of de novo lipogenesis from carbohydrate precursors and a consequent lowering of very-low density lipoprotein secretion into the circulation. In addition, the acarbose-induced dampening of the postprandial excursion of insulin may have maintained higher LPL activity in the heart, which would be liable to participate in the hypotriacylglycerolemic action of the inhibitor.

Acarbose↗
PubMed1996

Functional regions of the mouse thrombopoietin receptor cytoplasmic domain: evidence for a critical region which is involved in differentiation and can be complemented by erythropoietin.

Thrombopoietin (TPO) is the major regulator of growth and differentiation of megakaryocytes. To identify functionally important regions in the cytoplasmic domain of the TPO receptor, mpl, we introduced wild-type mpl and deletion mutants of murine mpl into the granulocyte-macrophage colony-stimulating factor (GM-CSF)- or erythropoietin (EPO)-dependent human cell line UT7. TPO induced differentiation of UT7-Wtmpl cells, not parental UT7 cells, along the megakaryocytic lineage, as evidenced by decreased proliferation, changes in cell morphology, and increased surface expression and mRNA levels of megakaryocytic markers CD41, CD61, and CD42b. When UT7-mpl cells were cultured long-term in EPO instead of GM-CSF, the TPO effect was dominant over that of EPO. Moreover, the differentiation induced by TPO was more pronounced for cells shifted from EPO to TPO than for cells shifted from GM-CSF to TPO, as shown by the appearance of polyploid cells. Mutational analysis of the cytoplasmic domain of mpl showed that proliferation and maturation functions of mpl can be uncoupled. Two functional regions were identified: (i) the first 69 amino acids comprising the cytokine receptor motifs, box I and box 2, which are necessary for both TPO-induced mitogenesis and maturation; and (ii) amino acids 71 to 94, which are dispensable for proliferation but required for differentiation. Surprisingly, however, EPO could complement this latter domain for TPO-induced differentiation, suggesting a close relationship between EPO and TPO signaling.

Animals↗
PubMed1996

[Parkinsonian syndrome and post-encephalitic stereotyped involuntary movements responsive to L-dopa].

In 1954, when he was five years old, a patient suffered from encephalitis with a prolonged lethargic state. Following this episode, he presented a severe parkinsonian syndrome which was associated, after a few years, with an axial dystonia and stereotyped involuntary movements of the upper limbs. These abnormal movements were particular by their coordinated appearance, their rhythmicity and their relative slowness. Treatment with L-dopa suppressed all akinetic, dystonic and dyskinetic symptoms. At age of 40 years, all the akinetic, dystonic and dyskinetic symptoms reappeared after drug withdrawal. Cerebral computed tomography, magnetic resonance imaging and fluorodeoxyglucose positron emission tomography were normal. Fluorodopa positron emission tomography revealed a significant bilateral reduction of tracer accumulation in the posterior part of both putamen, similar to that observed in patients with idiopathic Parkinson's disease. In this patient, pharmacological tests revealed that effectiveness of L-dopa was abolished by administration of a D2 antagonist, and was fully reproduced by a D2 agonist. Clinical signs, pharmacological data and past-medical history strongly suggested a limited lesion of the zona compacta of substantia nigra induced by viral agression. This complex and progressive extrapyramidal syndrome had strong similarities with the lethargic encephalitis of Von Economo and its late symptoms. Other diseases associating akinesia and dyskinesia or dystonic phenomena, like dopa-sensitive dystonia and juvenile Parkinson's disease, are very unlikely. Thus, the persistance of sporadic forms of Von Economo's encephalitis could be discussed.

Adult↗
PubMed1996

Thrombocytemia and abnormal megakaryopoiesis associated with abnormality of chromosome 1p34 in myelodysplastic syndromes.

Myelodysplastic syndromes (MDS) are a heterogeneous group of diseases characterized by a cytopenia related to abnormal proliferation and differentiation of marrow precursor cells. Some subtypes of MDS are associated with thrombocytemia or abnormal megakaryopoiesis and certain specific karyotypic abnormalities. We report on four cases of MDS with normal or elevated blood platelet count and a recurring abnormality in chromosome 1p34. The gene involved appears to be different from c-mpl and TPO.

Aged↗