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F Vidal

Publications and source records attributed to F Vidal.

At least 37 records · Page 2Linked to original sources
PubMed2004

Preimplantation genetic diagnosis in patients with male meiotic abnormalities.

Indications and candidates for preimplantation genetic diagnosis (PGD) have increased in recent years. This study evaluates whether IVF-intracytoplasmic sperm injection (ICSI) results could be improved by selecting embryos through PGD-AS (aneuploidy screening) in couples in whom the male partner presents meiotic abnormalities. Two hundred and fifty-six embryos were biopsied and 183 were suitable for analysis (73.2%). Ninety-two embryos showed normal chromosomal analysis (50.3% of the analysed embryos and 57.5% of the diagnosed embryos). Pregnancy, abortion and implantation rates were compared with 66 IVF-ICSI cycles performed in 44 patients with meiotic abnormalities without PGD (control group). No statistically significant differences in the pregnancy rate (52 versus 43.9%), implantation rate (32.1 versus 23.5%) and miscarriage rate (15.4 versus 10.3%) were observed between the groups. Although the embryos obtained from men with meiotic abnormalities showed a high frequency of chromosome abnormalities, no improvements in pregnancy and implantation rates were obtained after PGD-AS in the series analysed.

Abortion, Spontaneous↗
PubMed2004

Influence of the laser pulse duration on spectrochemical analysis of solids by laser-induced plasma spectroscopy.

Quantitative analysis of aluminum and copper alloys by means of laser-induced plasma spectroscopy (LIPS) has been investigated for three representative laser pulse durations (80 fs, 2 ps, and 270 ps). The experiments were carried out in air at atmospheric pressure with a constant energy density of 20 J/cm2. Because the decay rate of the spectral emission depends on the laser pulse duration, the optimum detection requires an optimization of the temporal gating acquisition parameters. LIPS calibration (sensitivity and nonlinearity) and the limit of detection (LOD) are discussed in detail. While the LOD of minor elements embedded in alloy samples obtained by sub-picosecond or sub-nanosecond laser pulses are both time and element dependent, provided an appropriate temporal window is chosen, the optimum LODs (several parts per million (ppm)) prove to be independent of the laser pulse duration. Finally, it is found that for elements such as those detected here, gated LIPS spectra using picosecond or sub-picosecond laser pulses provide much better LOD values than non-gated spectra.

Journal Article↗
PubMed2003

Association study between corticotrophin-releasing hormone genomic region (8q13) and rheumatoid arthritis in the Spanish population.

OBJECTIVE: To investigate whether the corticotrophin-releasing hormone (CRH) genomic region confers genetic susceptibility to rheumatoid arthritis (RA) in the Spanish population. METHODS: DNA was obtained from 121 simplex RA families and 101 healthy controls, all from Spanish origin. Two microsatellites, CRHRA1 and CRHRA2, located 25 and 20 kb downstream respectively from the CRH gene were examined using a new multiplex design. Linkage disequilibrium (LD) between the markers was assessed and association studies were carried out using the transmission disequilibrium test (TDT) implemented in TRANSMIT. RESULTS: Both markers are in Hardy-Weinberg equilibrium and there is significant LD between them in the Spanish population. Neither the polymorphic alleles of CRHRA1 and CRHRA2 markers nor their resulting haplotypes were significantly associated to RA. The associated haplotype in the UK population (CRHRA1*10; CRHRA2*14) was undertransmitted in RA patients (12 obs vs 17.43 exp), although the difference is not statistically significant (P > 0.05). CONCLUSIONS: This is the first follow-up study of the association between the CRH genomic region and RA and suggests that the CRH gene may not be involved in the pathogenesis of RA in the Spanish population. Further studies in other populations will help untangle the real contribution of this genomic region to the susceptibility to RA.

Arthritis, Rheumatoid↗
PubMed2003

Genetic analysis of sperm and implications of severe male infertility--a review.

The use of fluorescence in situ hybridization (FISH) on decondensed sperm heads has allowed to analyse the chromosome constitution of spermatozoa in different populations. In controls, the mean incidence of disomy (including all chromosomes) is about 6.7 per cent; diploidy increases with age, and some individuals may show a special tendency to nondisjunction. Carriers of numerical sex chromosome anomalies show a low incidence of sex chromosome disomies (2.54-7.69 per cent), and the need to screen ICSI candidates for these conditions has to be reconsidered. Carriers of inversions produce from 0 to 54.3 per cent abnormal sperm. Carriers of Robertsonian translocations produce from 3.4 to 36.0 per cent abnormal sperm, and carriers of reciprocal translocations produce from 47.5 to 81.0 per cent abnormal spermatozoa. However, carriers of translocations usually produce more abnormal embryos than expected from these figures. This may be partly related to interchromosomal effects induced by some structural reorganizations. Males with oligoasthenozoospermia, low motility and/or high FSH concentrations show frequent synaptic anomalies, resulting in the production of aneuploid and diploid sperm. Testicular sperm show extremely high rates of chromosomal abnormalities. The risk of recurrent abortion is increased by the presence of chromosome abnormalities in sperm.

Cell Nucleus↗
PubMed2003

Error negativity on correct trials: a reexamination of available data.

The error negativity, an EEG wave observed when subjects commit an error in a choice reaction time (RT) task, is often considered as a sign of error detection. Recently, reports of Ne-like waves on correct responses did challenge this interpretation. It has been proposed, however, that these Ne-like waves result either from an artifactual contamination of response-locked activities by stimulus-locked ones, or from an implicit monitoring of the time elapsing during the RT. Our aim was to reprocess published data: (1) to compare the shape and amplitude of EMG-locked and stimulus-locked ERPs on correct trials, and (2) to compare the size of the EMG-locked Ne-like waves obtained on fast and slow trials. The results neither support the artifact hypothesis nor the RT monitoring one. Therefore, it seems that the Ne-like waves observed on correct trials do correspond to a Ne, which suggests that the Ne has a broader significance than just error detection.

Adult↗
PubMed2003

The influence of time preparation on motor processes assessed by surface Laplacian estimation.

OBJECTIVE: The present study was aimed at testing whether foreperiod duration affects the activity recorded over the primary sensorimotor cortices during the reaction time. METHODS: The foreperiod duration (500 or 2500 ms) was varied across blocks of trials during a between-hand choice reaction time task; surface Laplacians were estimated from EEG recordings by the source derivation method. RESULTS: Reaction time was shorter for the 500 ms foreperiod than for the 2500 ms foreperiod. A contralateral negativity/ipsilateral positivity pattern showed up over the primary sensorimotor cortices. The time between the contralateral negativity onset and the electromyographic onset was shorter for the 500 ms foreperiod than for the 2500 ms foreperiod, which suggests that the foreperiod affects the implementation of the motor command. Furthermore, the interval between the onset of the voluntary electromyographic activity and the mechanical response was shorter for the 500 ms foreperiod than for the 2500 ms foreperiod. CONCLUSIONS: These results indicate that time preparation affects both central and peripheral motor processes.

Adult↗
PubMed2003

Chromosomal abnormalities and embryo development in recurrent miscarriage couples.

BACKGROUND: Chromosomal abnormalities are an important cause of spontaneous abortion and recurrent miscarriage (RM). Therefore, we have analysed the incidence of chromosomal abnormalities and embryo development in patients with RM. METHODS: Preimplantation genetic diagnosis (PGD) was performed on 71 couples with RM and 28 couples undergoing PGD for sex-linked diseases (control group). Chromosomes 13, 16, 18, 21, 22, X and Y were analysed by fluorescence in-situ hybridization. RESULTS: The implantation rate in RM patients was 28% and three patients (13%) miscarried. The percentage of abnormal embryos was significantly increased (P < 0.0001) in RM patients compared with controls (70.7 versus 45.1%). All of the embryos were abnormal in 19 cycles (22.1%) and repeated PGD cycles yielded similar rates of chromosomal abnormalities in 14 couples. Anomalies for chromosomes 16 and 22 were significantly higher (P < 0.01) in RM cases. In the RM population, euploid embryos reached the blastocyst stage more frequently than abnormal embryos (61.7 versus 24.9%; P < 0.0001). CONCLUSIONS: RM is associated with a higher incidence of chromosomally abnormal embryos, of which some are able to develop to the blastocyst stage. IVF plus PGD is an important step in the management of these couples, but the technique has to move towards a full chromosome analysis.

Abortion, Habitual↗
PubMed2003

Bacteraemia in adults due to glucose non-fermentative Gram-negative bacilli other than P. aeruginosa.

BACKGROUND: Glucose non-fermentative Gram-negative bacilli other than P. aeruginosa (NF) are emerging pathogens. AIM: To evaluate the epidemiology, clinical characteristics, predictors of acquisition, and outcome of bacteraemia due to NF. DESIGN: Retrospective analysis of prospectively recorded data. METHODS: We reviewed episodes of NF bacteraemia in patients older than 14 years, recorded through a blood culture surveillance program. Patients were identified at the time of their bacteraemia and prospectively followed. RESULTS: Between January 1991 and December 2000, 296 episodes of NF bacteraemia were detected: 87% were due to Acinetobacter sp., Pseudomonas sp. other than P. aeruginosa, or Stenotrophomonas maltophilia. The global incidence (0.87 cases per 1000 discharges) remained stable during the study period. Patients were of all ages and both sexes, and 282/296 (95.3%) had some predisposing underlying disease or condition, the most common being haematological malignancies without transplantation (85/296, 28.7%), treatment with steroids (78/296, 26.3%), and transplantation (bone marrow or solid organ) (70/296, 23.6%). Fifty (16.9%) were neutropenic. The most common sources of bacteraemia were central venous catheter infection (117/296, 39.5%) and unknown primary site (97/296, 32.8%). Sixty-one episodes (20.6%) were community-acquired and 235 (79.4%) were nosocomial. Forty-three patients (14.5%) died. Pneumonia (RR 1.5, 95%CI 1.1-14.2), age<65 (RR 3.1, 95%CI 1.4-10.3), hospitalization in the intensive care unit (ICU) (RR 3.2, 95%CI 1.3-9.8), rapidly fatal disease (RR 4.9, 95%CI 3.1-12.6), and severe sepsis (RR 9.8, 95%CI 1.6-19.7) were independent predictors of death. Factors predicting the probability that an episode of nosocomial bacteraemia was due to NF included: rapidly fatal disease (RR 1.23, 95%CI 1.02-4.1), age<65 (RR 2.05, 95%CI 1.4-3), hospitalization in the ICU (RR 2.06, 95%CI 1.4-3, and pneumonia (RR 2.1, 95%CI 1.05-4.8). DISCUSSION: NF bacteraemia mainly affects patients with malignant haematological disease, with and without transplantation, and patients in the ICU. The most common known source is a central venous catheter, though many sources are unknown. Mortality is relatively low, and depends on the severity of the underlying disease.

Adolescent↗
PubMed2003

Selective effects of low-dose dopamine D1 and D2 receptor antagonists on rat information processing.

It is well established that the dopaminergic system influences simple reaction time (RT) performance. However, the role of this system in more complex information processing remains to be clarified. The present study was aimed at addressing this issue. To this end, we used an inferential method that relies on choice RT procedures and allows one to identify information processing stages in both humans and rats. Long-Evans rats responded to lateral visual cues (left or right). Two task factors, signal intensity and foreperiod duration, were manipulated. Low doses of two pharmacological agents, SCH 23390 (a D1 receptor antagonist; 0.015 and 0.025 micromol/kg) and eticlopride (a D2 receptor antagonist; 0.01 and 0.02 micromol/kg), were administrated systemically. Both drugs increased choice RT: eticlopride interacted with signal intensity on RT, showing that D2 receptors mediate at least the sensory stage of stimulus preprocessing. In addition, eticlopride interacted with signal intensity on omission rate, thereby suggesting an involvement of D2 receptors in attentional processes; and SCH 23390 interacted with foreperiod duration on RT, indicating that D1 receptors specifically mediate the response adjustment stage. The effect of this drug on RT rests entirely in its interaction with foreperiod duration, allowing us to conclude that this D1 antagonist affects the response adjustment stage while sparing all other processing stages.

Animals↗
PubMed2002

Fluid modeling of the laser ablation depth as a function of the pulse duration for conductors.

Laser ablation of an aluminum target as a function of the pulse duration, for fluences up to 30 J/cm(2) and a wavelength of 0.8 microm, is investigated by means of a fluid code. For a given fluence, the ablation depth shows a minimum for a pulse duration of approximately 10 ps between a maximum obtained for pulses shorter than approximately 1 ps and a lower maximum obtained for pulses in the nanosecond range, in qualitative agreement with published experimental results. The decrease in ablation depth with increase in pulse duration observed between 1 and 10 ps results from the reduced temperature rise near the surface due to increased inward heat transport. The increase in the ablation depth above approximately 10 ps is due to the increase in electron density gradient length while the laser pulse intensity is close to maximum, which thus enables the plasma to absorb more of the laser pulse energy for increased ablation.

Journal Article↗
PubMed2002

Activation of the supplementary motor area and of attentional networks during temporal processing.

This paper first provides a survey of the expanding brain imaging literature in the field of time processing, showing that particular task features (discrete vs rhythmic, perceptual vs motor) do not significantly affect the basic pattern of activation observed. Next, positron emission tomography (PET) data obtained in a timing task (temporal reproduction) with two distinct duration ranges (2.2--3.2 and 9--13 s) are reported. The stimuli consisted of vibrations applied to the subject's right middle finger. When the vibration ended, the subject estimated an interval identical to its length before pressing a response button. The control task used cued responses with comparable intervals and stimuli. The pattern of activation obtained in the timing task as compared to control mainly included areas having attentional functions (the right dorsolateral prefrontal, inferior parietal, and anterior cingulate cortices), and the supplementary motor area (SMA). No significant difference was seen as a function of the duration range. It is argued, firstly, that involvement of the attentional areas derives from specific relations between attention and the temporal accumulator, as described by dominant timing models; and, secondly, that the SMA, or more probably one of its subregions, subserves time processing.

Adult↗
PubMed2002

[PiSZ-phenotype alpha 1-antitrypsin deficiency: a rare cause of bronchiectasis].

Panacinar emphysema is the most characteristic pulmonary disease in patients with alpha1-antitrypsin deficiency (AAT). Bronchiectasis can also arise with AAT deficiency, although the association is much less common and no clear cause-effect relationship has yet been established. We report the case of a woman who presented with bronchiectasis and PiSZ-phenotype ATT deficiency, without emphysema. A review of the literature showed that the case is exceptional.

Bronchiectasis↗
PubMed2002

Diploid sperm and the origin of triploidy.

Trisomy 16, the 45,X monosomy and triploidy are the more frequent chromosome anomalies in spontaneous abortions. Earlier estimations, based on frequencies of diandric triploidy at conception, resulted in a good correlation with the frequencies of diploid sperm in infertile males (up to 1.9%). Recent data have shown that most diandric triploids originate by dispermy, although 8.3% of them are produced by diploid sperm resulting from meiotic errors. Using these data, the estimated frequency of diploid sperm is still in good correlation with the percentage above. Furthermore, analysis of male pronuclei (PN) in 3PN zygotes produced by ICSI with sperm from oligo-, crypto- and azoospermic males revealed that 33.3% of them were diploid, while none of the PN produced by normozoospermic males by IVF was. The estimated frequency of diploid sperm in these infertile males is also in good correlation with the previous figures. The data suggest that most diandric triploids are produced by normozoospermic males by dispermy, while most diandric triploids produced by oligozoospermic males would result from fertilization by unreduced, diploid sperm.

Abortion, Spontaneous↗
PubMed2002

Risk assessment and segregation analysis in a pericentric inversion inv6p23q25 carrier using FISH on decondensed sperm nuclei.

Fluorescent in situ hybridization (FISH) in decondensed sperm nuclei has been used to determine the percentage of normal/balanced or unbalanced spermatozoa produced by an inv(6)(p23q25) carrier, and the possible interchromosomal effect (ICE) of the reorganized chromosomes on other chromosome pairs. A dual color FISH with specific subtelomeric probes for the 6p and 6q regions was performed to determine the segregation pattern of the inverted chromosome. ICE on chromosomes 18, X and Y was assessed using a triple color FISH assay. In the segregation analysis 10,049 spermatozoa were analyzed, and only 45.7% of them were normal/balanced. The high number of unbalanced gametes in our carrier could be the consequence of the large size of the inverted segment. This situation could facilitate the formation of an inversion loop, where formation of an odd number of chiasmata (usually one) result in the production of 50% normal and 50% unbalanced sperm. Furthermore, an increase in the disomy rate for chromosome 6 was also observed. In the screening for ICE, 10,007 spermatozoa were analyzed. The disomy rate for the sex chromosomes and chromosome 18 were not significantly different from those found in our controls, suggesting no evidence of interchromosomal effects in this patient. The use of FISH in decondensed sperm nuclei has proved once more to be an accurate approach to determine the chromosome anomalies in sperm and could help to better establish a reproductive prognosis.

Adult↗
PubMed2001

Chromosomal abnormalities in sperm.

The use of FISH (fluorescent in situ hybridization) in decondensed sperm nuclei has allowed, during the last decade, to indirectly study the chromosome constitution of human spermatozoa. Studies in control populations have been used to set up the basal level of aneuploidy for all human chromosomes and, based on conservative estimates, the percentage of chromosomally abnormal sperm in the general population could be considered to be at least 6.7%. In carriers of sex chromosome numerical anomalies and in severe oligozoospermic males (both frequent candidates for intracytoplasmic sperm injection), in structural chromosome carriers (enrolled in preimplantation genetic diagnosis programs) and in couples with recurrent miscarriage, sperm chromosome analyses by FISH could help to better establish a reproductive prognosis.

Cell Nucleus↗
PubMed2001

Fluctuation induced diamagnetism in the zero magnetic field limit in a low temperature superconducting alloy.

By using a Pb-18 at. % In alloy, the fluctuation induced diamagnetism was measured in the zero magnetic field limit, never observed until now in a low-T(C) superconductor. This allows us to disentangle the dynamic and the nonlocal electrodynamic effects from the short-wavelength fluctuation effects. The latter may be explained on the grounds of the Gaussian-Ginzburg-Landau approach by introducing a total energy cutoff in the fluctuation spectrum, which strongly suggests the existence of a well-defined temperature in the normal state above which all fluctuating modes vanish. This conclusion may also have implications when describing the superconducting state formation of the high-T(C) cuprates.

Journal Article↗
PubMed2001

A kinetic study of the oxidation of S(IV) in seawater.

Flue gas desulfurization by means of SO2 absorption in seawater is a well-known process. However, it can be optimized if the oxidation kinetics of dissolved S(IV) is known. Laboratory reactor experiments in which the pH and temperature were controlled, determined the oxidation kinetics of S(IV) in seawater. This study conclusively shows that the order with respect to S(IV) is one and that the order with respect to oxygen is zero. The kinetic constant depends greatly on the temperature and on the pH; consequently, the activation energy and a relationship between the kinetic constant and the hydrogen proton concentration (2 < pH < 6) were also obtained.

Air Pollution↗