Unexpected Angelman syndrome molecular defect in a girl displaying clinical features of Prader-Willi syndrome.
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Aneuploidy↗
Biomedical subjects
C Vasseur
Publications and source records attributed to C Vasseur.
Potential pitfall in Prader-Willi syndrome and Angelman syndrome molecular diagnosis.
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Angelman Syndrome↗
Genes and premature ovarian failure.
Premature ovarian failure (POF) is an heterogeneous syndrome. Among genetic causes, X monosomy as in Turner syndrome or X deletions and translocations are known to be responsible for POF. The genes involved in ovarian function, located on the X chromosome are still unknown. On the other hand, autosomal abnormalities have been identified in POF patients such as mutations of the FSH gene, the LH and FSH receptor genes, chromosome 3q containing the blepharophimosis gene, the ATM gene (Ataxia-telangiectasia gene). Mutations in the AIRE gene (responsible for APECED syndrome) can involve ovarian insufficiency. It is likely that studies on the function of the protein AIRE might improve our knowledge on follicular development. Furthermore, different mouse models of ovarian failure such as mouse lacking connexins or mice lacking GDF9 (growth derived factor 9), might increase our knowledge of ovarian failure. In the future, a better knowledge of the cellular and biochemical components involved in folliculogenesis and apoptosis should elucidate the mechanisms of POF.
Animals↗
Whole-body exercise thallium imaging in smokers.
Whole-body exercise thallium imaging (WBEI) can show abnormalities of leg muscle perfusion in patients with symptomatic peripheral artery disease (PAD). This study compared the exercise distribution of thallium-201 at different levels of the legs in asymptomatic smokers and non-smokers who performed a maximal graded treadmill test. A group of 74 smokers (more than 20 pack-years) with (n = 51) or without coronary artery disease (CAD) (n = 23) were included in group 1 and 64 non-smokers with a low probability of PAD and CAD in group 2. Patients in group 1 were older than the patients in group 2 (58 +/- 9 versus 48 +/- 12 years, p < 0.0001). Indexes of asymmetry were significantly higher in group 1, at each level of the legs, both in anterior and posterior views (0.001 < p < 0.05), except at thigh level in anterior view. Fractional uptake indexes of thallium-201 were significantly lower in group 1 than in group 2 at calf level (p = 0.0001 in anterior and posterior views) and buttocks (p = 0.006 and p = 0.009 in anterior view only). Interextremity asymmetry was four to six times more frequent at calf level in smokers than in non-smokers. These WBEI abnormalities in smokers are highly suggestive of silent PAD or at least decreased vascular reactivity in clinically uninvolved vessels.
Adult↗
Effect of several decontamination procedures on Listeria monocytogenes growing in biofilms.
Listeria monocytogenes is a pathogenic bacterium which has been implicated in several foodborne illnesses. This microorganism grows into biofilms attached to the surfaces in food-processing plants, increasing its resistance to antimicrobial agents. The present work was realized to investigate the attachment of L. monocytogenes isolates to glass surfaces and to find a decontamination procedure to remove these bacteria in biofilms. Three-day biofilms were prepared by growing L. monocytogenes isolates from food plant environments on glass surfaces. Sixteen decontamination treatments at different pHs, temperatures, and times of exposure were tested against L. monocytogenes biofilms. The most efficient treatments were those applied at 63 degrees C. Combinations of decontamination treatments applied at 55 degrees C for 30 min provided different results according to the other factors used. In general, L. monocytogenes biofilms were found to be not very susceptible to high osmolarity (10.5% NaCl), and the interaction of sodium chloride and acid did not seem to have important effects in inactivating these bacteria (from a 1.3-to a 1.9-log-CFU/cm2 reduction). The combination of NaOH (pH 10.5; 100 mM) and acetic acid (pH 5.4; 76.7 mM) applied sequentially at 55 degrees C for even 5 min was shown to be the most effective treatment to remove L. monocytogenes from biofilms (at least a 4.5-to 5.0-log-CFU/cm2 decline).
Acetic Acid↗
[Gynecomastia. Management of diagnosis and therapy. Apropos of 52 cases].
Gynecomastia is the commonest breast lesion in males. Fifty-two patients (mean age 24 years) operated in our department were reviewed with a mean follow-up of two years and a half. Gynecomastia occurred most frequently during puberty (63%), was bilateral (75%) and idiopathic (65%). The size of the enlargement was evaluated according to Simon's-classification based on breast-volume and skin-redundancy. 18 stage 1, 22 stage 2A, 9 stage 2B, 3 stage 3. Clinical examination and mammography determined the consistency of gynecomastia: adipose or firm. 4 different surgical managements were used: 32 subcutaneous mastectomies, 12 liposuctions, 6 liposuctions assocaited with subcutaneous mastectomy, 1 total mastectomy. One patient had liposuction on one side and subcutaneous mastectomy on the other one. All techniques gave good morphologic results. Nonetheless, the authors recommend the combination "liposuction and subcutaneous mastectomy", as this technique presents many advantages: small intraoperative blood loss, good skin redraping, short hospital stay, complete histologic examination of the material removed.
Adolescent↗
Diacetyl and acetoin production from the co-metabolism of citrate and xylose by Leuconostoc mesenteroides subsp. mesenteroides.
The co-metabolism of citrate plus xylose by Leuconostoc mesenteroides subsp. mesenteroides results in a growth stimulation, an increase in D-lactate and acetate production and repression of ethanol production. This correlated well with the levels of key enzymes involved. A partial repression of alcohol dehydrogenase and a marked stimulation of acetate kinase were observed. High citrate bioconversion yields in diacetyl plus acetoin were obtained at pH 5.2 in batch (11.5%) or in chemostat (up to 17.4%) culture. In contrast, no diacetyl or acetoin was detected in citrate plus glucose fermentation.
Acetoin↗
Does hydrosalpinx reduce the pregnancy rate after in vitro fertilization?
OBJECTIVE: To determine the effect of hydrosalpinges on the pregnancy rate in an IVF program. DESIGN: Multicentric retrospective analysis of clinical and laboratory data. SETTING: Two assisted reproductive technology centers in university hospitals. PATIENT(S): Four hundred forty-three women, under 38 years of age, with pure tubal infertility. The patients were classified into the following five groups: bilateral hydrosalpinges (n = 37), unilateral hydrosalpinx (n = 54), bilateral tubal occlusion (n = 207), unilateral tubal occlusion (n = 55), and severe tubal disease without complete occlusion (n = 90). MAIN OUTCOME MEASURE(S): Pregnancy and implantation rates. RESULT(S): The pregnancy and the implantation rates per transfer (12.3% and 5.4%) obtained by women with bilateral hydrosalpinges are significantly lower than the rates (means = 23.1% and 12%) for all other tubal infertility groups. CONCLUSION(S): Bilateral hydrosalpinges have a deleterious effect on the outcome of IVF program.
Adult↗
PEG1 expression in maternal uniparental disomy 7.
PAG1/MEST is an imprinted gene mapping to human chromosome 7q32. In human embryos and placenta, PEG1 is expressed from the paternally derived allele only, while maternal and paternal alleles are transcribed in adult blood lymphocytes. We aimed at investigating the origin of the maternal PEG1 transcript by studying PEG1 mRNA in two maternal uniparental disomy 7 patients suffering from severe pre- and post-natal growth restriction. PEG1 expression has been characterised by RT-PCR from leukocytes RNA using several primer pairs. The distal coding region in PEG1 mRNA could be repeatedly amplified from mUPD patients blood cells, but no amplification could be performed from the first exon, suggesting that the first exon was not a component of the maternal PEG1 transcript. As six independent database sequences showed that exon 2 was exactly joined to a novel sequence unrelated to exon 1 but identical in the common region of the six sequences, we hypothesized that our observation of PEG1 expression in the two maternal uniparental disomy 7 patients could be explained by transcription of the maternal allele from an alternate maternal upstream promoter.
Chromosome Aberrations↗
Two mutations in recombinant Hb beta F41(C7)Y, K82 (EF6)D show additive effects in decreasing oxygen affinity.
Based on the properties of two low oxygen affinity mutated hemoglobins (Hb), we have engineered a double mutant Hb (rHb beta YD) in which the beta F41Y substitution is associated with K82D. Functional studies have shown that the Hb alpha 2 beta 2(C7)F41Y exhibits a decreased oxygen affinity relative to Hb A, without a significantly increased autooxidation rate. The oxygen affinity of the natural mutant beta K82D (Hb Providence-Asp) is decreased due to the replacement of two positive charges by two negative ones at the main DPG-binding site. The functional properties of both single mutants are interesting in the view of obtaining an Hb-based blood substitute, which requires: (1) cooperative oxygen binding with an overall affinity near 30 mm Hg at half saturation, at 37 degrees C, and in the absence of 2,3 diphosphoglycerate (DPG), and (2) a slow rate of autooxidation in order to limit metHb formation. It was expected that the two mutations were at a sufficient distance (20 A) that their respective effects could combine to form low oxygen affinity tetramers. The double mutant does display additive effects resulting in a fourfold decrease in oxygen affinity; it can insure, in the absence of DPG, an oxygen delivery to the tissues similar to that of a red cell suspension in vivo at 37 degrees C. Nevertheless, the rate of autooxidation, 3.5-fold larger than that of Hb A, remains a problem.
Hemoglobins↗
Loss of allosteric behaviour in recombinant hemoglobin alpha 2 beta 2(92)(F8) His-->Ala: restoration upon addition of strong effectors.
In the stereochemical model proposed by Perutz [1], the Fe-His(F8) bond plays a significant role in the allosteric transition in hemoglobin and the resulting cooperativity in ligand binding. When this bond is ruptured, there is a loss in the transmission of the information concerning ligand binding; examples are Hb(NO)4 in the presence of inositol hexakisphosphate (IHP), or nickel substituted Hb hybrids which, despite being liganded, exhibit deoxy-like properties. To study the effects of the loss of the iron proximal histidine bond, we have engineered the alpha 2 beta 2(F8)H92A recombinant Hb. The replacement of the highly conserved proximal histidine F8 residue by an alanine results in a low affinity for the heme group and a loss of the allosteric properties; kinetics of CO recombination after photodissociation show only the rapid bimolecular phase, characteristic of the high affinity R-state. However, a significant amount of deoxy (T-state) kinetics are observed after addition of external effectors such as IHP. The iron-histidine bond is apparently crucial for the heme-heme interaction, but the allosteric equilibrium may still be influenced by external constraints.
Alanine↗
Treatment planning optimization by conjugate gradients and simulated annealing methods in stereotactic radiosurgery.
PURPOSE: This paper presents a new optimization method of treatment planning in linac stereotactic radiosurgery. METHODS AND MATERIALS: On a workstation integrating x-rays, computed tomography (CT), magnetic resonance imaging (MRI), and digital subtracted angiography (DSA) images, we first determine the outlines of the target volume and surrounding healthy tissues to spare. To achieve complete optimization of the treatment plans, this method decomposes the optimization process in two steps. The position of the isocenters and the diameter of the collimators are first deduced by a conjugate gradients method, from the position and size of ellipsoids or spheres modeling the target volume. The other irradiation parameters, such as the isocenter dose, the aperture, and the weight of each irradiation plane and of their irradiation sectors are finally deduced by a simulated annealing optimization algorithm. RESULTS: The system can perform multitarget/multisector treatment plans that are automatically obtained in a satisfactory time (as a rule, 20 min for a two-target irradiation), much faster than the time needed for a manual treatment planning. We present the results in two cases: the simulation of a single-target treatment and a two-target real treatment with constraints. In these two cases, we can control the dose received by target and sensitive volumes. CONCLUSION: This method achieves an excellent conformation of the estimated isodose curves with the outlines of the target volume, which allows us to avoid the surrounding healthy tissues, thanks to the different weighting factors given on each volume concerned according to the importance we grant to each of them.
Angiography, Digital Subtraction↗
A frameless stereotaxic localisation system using MRI, CT and DSA.
The authors present a method of stereotaxic localisation using magnetic resonance imaging (MRI) computerized tomography (CT) and digital subtracted angiography (DSA) which does not require localisation frams fixed to the patient's skull, but uses only four cranial landmarks corresponding to the holders of the neurosurgical stereotaxic frame. The method presents no major constraints in routine examinations. The geometrical distortions of the imaging devices are corrected. Three-dimensional localisation is performed using sagittal and axial slices in MRI, axial slices in CT and only two associated frontaly and lateral views in DSA. The images data are transferred to a PC-based system. By locating the landmarks on the images, the transformation matrixes can be computed to obtain the 3D coordinates of a target in the stereotaxic space and in any imaging modality. The results obtained show the precision of the corrections and the millimetre accuracy of pin-point target localisation.
Angiography, Digital Subtraction↗
[Palmar burns of the hand in children. 81 cases].
The authors reviewed 81 children between the ages of 5 months and 3 years suffering from palmar burns of hands from 1988 to 1992. Most burns were unilateral (53), superficial 2nd degree (48), due to contact (55), in boys (48) and only affecting the palm (69). The initial treatment consisted of directed healing followed by a split-skin graft in 8 cases. The initial scar was not retracted in 58 cases, retracted in 17 cases and hypertrophic in 8 cases. 79% of children had no sequelae at 12 months. At more than three years, 15% of children (12) had sequelae: 9 adhesions of the first commissure, 5 flexion deformities of long fingers, 3 clinodactylies, 1 syndactyly. All were operated by trident plasties, Colston flaps or full-thickness skin graft. A final functional assessment was performed. 90% of children had no sequelae. Four children still presented moderate functional discomfort (3 adhesions of the first commissure requiring reoperation, one case of decreased sensitivity). Palmar burns in children have a good prognosis. Factors of severity are: involvement of the 1st commissure, associated dorsal burn, deep 2nd degree, poor social conditions, delayed management.
Burns↗
Unstable alpha-chain hemoglobin variants with factitious beta-thalassemia biosynthetic ratio: Hb Questembert (alpha 131[H14]Ser-->Pro) and Hb Caen (alpha 132[H15]Val-->Gly).
Hb Questembert [alpha 131(H14)Ser-->Pro] was found in several members of a French family suffering from congenital Heinz body anemia. The unstable hemoglobin was expressed in the peripheral red blood cells at a very low level. Globin biosynthetic studies revealed a high specific activity of the abnormal chain and an alpha-/beta-labeling ratio similar to that of beta-thalassemia trait. Hb Caen [alpha 132(H15) Val-->Gly] is another unstable variant with the same globin biosynthesis abnormality. In both cases the structural modification is localized at the end of the H helix, a region encoded by the third exon. The mechanism for the unbalanced globin synthesis is not yet clear. It may be related 1) to a defect in chain assembly, 2) to an increased rate of degradation of the variant chain followed by the release of unlabeled beta-chains from the abnormal hemoglobin, thus leading to an apparent suppression of beta-chain synthesis, or 3) to a modified stability of the abnormal alpha-globin mRNA.
Adult↗
Bone mineral and fat measurement with a novel dual photon absorptiometer.
The authors have produced an original dual-photon absorptiometer, with specific algorithms, permitting real-time automatic bone recognition, to reduce examination time (to 5 min). It permits the simultaneous measurement of the mineral density of an area of bone (BMD), the fat percentage of the soft tissues (PFST) that surround it, and the variation in this percentage. It visually represents, on one and the same picture, freely defined in terms of dimension and definition, bone mineral distribution and fat mass distribution. The performances are analysed, using phantoms and taking ten control subjects, in the region of the femoral neck. The variations in PFST in the control subjects are compared with the measurements carried out in MRI in the same region. In all these control subjects, there is a regular decrease in PFST in this region along an upper external/lower internal axis. This decrease has been likened to a regression line, the slope of which, representing between -0.16 per cent of fat per cm and -1.7 per cent per cm, has a mean value of -0.81 per cent per cm. The BMD is thus reduced by 0-2.5 per cent, depending on the subjects.
Absorptiometry, Photon↗
Hemoglobin Thionville. An alpha-chain variant with a substitution of a glutamate for valine at NA-1 and having an acetylated methionine NH2 terminus.
In hemoglobin (Hb) Thionville, the substitution of a glutamic acid for the alpha-chain NH2-terminal valine inhibits the cleavage of the initiator methionine which is then acetylated. The elongation of the alpha-chain NH2 terminus modifies the three-dimensional structure of hemoglobin at a region that is known to have an important role in the allosteric regulation of oxygen binding. Relative to Hb A, Hb Thionville has a lower affinity for oxygen, and the heterotropic allosteric effects of protons, chloride, and bezafibrate are reduced. In contrast, the response to 2,3-diphosphoglycerate is normal. Analysis of oxygen equilibrium data within the framework of the two-state allosteric model indicates that the structure of deoxy Hb Thionville is stabilized relative to that of deoxy Hb A. The x-ray crystal structure of deoxy Hb Thionville shows that the glutamate side chain extends away from the alpha 1-alpha 2 interface, whereas the methionine side chain (which has two conformations) extends into the alpha 1-alpha 2 interface, physically displacing chloride and bezafibrate. The increased stability of deoxy Hb Thionville is due to new intrasubunit and intersubunit contacts made by the methionine. These interactions replace the indirect contacts, made through bound chloride ions, that Val-1 alpha normally contributes to the alpha 1-alpha 2 interface.
Acetylation↗
Structure of the EF corner favors deamidation of asparaginyl residues in hemoglobin: the example of Hb La Roche-sur-Yon [beta 81 (EF5) Leu----His].
Some abnormal hemoglobins constitute models which allow one to evaluate the structural requirements for post-translational modifications in proteins, such as deamidation. Hb La Roche-sur-Yon [beta 81 (EF5) Leu----His] is an unstable hemoglobin variant displaying a moderately increased oxygen affinity. About half of the abnormal hemoglobin, in addition to the substitution at position beta 81, carries a deamidation of the neighboring asparagine residue, beta 80 (EF4). The histidine at position beta 81 cannot fit into the small hydrophobic pocket which normally accomodates the leucine residue. This structural change opens the heme pocket and modifies the general conformation of the EF segment, thus explaining the increase in oxygen affinity and the achievement of a three-dimensional structure favoring asparagine deamidation. Histidine beta 81 could also act as a catalyst in the deamidation reaction. Deamidation has already been reported for two other variants of the EF corner, Hb Providence [beta 82 (EF6) Lys----Asn] and Hb J Singapore [alpha 79 (EF8) Ala----Gly]. In all these cases it seems that a histidine may catalyze the deamidation of the asparagine residues and that disturbing the folding of the EF corner will provide an extra flexibility favoring the reaction.
Adolescent↗