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Biomedical subjects

F Vidal

Publications and source records attributed to F Vidal.

At least 91 records · Page 5Linked to original sources
PubMed1999

Implications of sperm chromosome abnormalities in recurrent miscarriage.

PURPOSE: Our purpose was to assess the existence of sperm chromosome abnormalities in recurrent pregnancy loss in an assisted reproduction program. METHODS: In this prospective study, 12 sperm samples from couples undergoing in vitro fertilization with two or more first-trimester spontaneous abortions were analyzed. Diploidy and disomy in decondensed sperm nuclei were assessed for chromosomes 13, 18, 21, X, and Y using two- and three-color fluorescence in situ hybridization. RESULTS: Sex chromosome disomy in sperm samples from recurrent abortion couples was significantly increased compared to that from internal controls (0.84% vs 0.37%). In a subpopulation of seven couples who underwent oocyte donation, mean frequencies for sex chromosome disomy (1%) were even higher and diploidy (0.43%) was also significantly increased. CONCLUSIONS: These results suggest an implication of sperm chromosome abnormalities in some cases of recurrent pregnancy loss.

Abortion, Habitual↗
PubMed1999

Amino acid polymorphism at residue 71 in HLA-DR beta chain plays a critical role in susceptibility to ulcerative colitis.

The association of ulcerative colitis with distinct HLA-DRB1 alleles has not been easy to ascertain. Recent studies show that among HLA-DR2 alleles, DRB1*15 but not DRB1*16, is associated with the disease. Similarly, in the HLA-DR1 group, only DRB1*0103 is increased in ulcerative colitis patients. The aim of our study was to identify critical DRB1 residues that might account for these differences. We typed 121 patients with ulcerative colitis and 275 controls using gene amplification and sequence-specific oligonucleotide probing for HLA-DRB1 and DRB3. We observed a strong negative association between HLA-DRB1 alleles that encode lysine at position 71 in their beta-chain and susceptibility to ulcerative colitis. Differences in the prevalence among other alleles differing only in the third hypervariable region suggested a hierarchy of susceptible and protective class II alleles related to the presence of an acidic, neutral, or basic amino acid residue at position 71. These data implicate most strongly the amino acid residues in the third hypervariable region of the DRbeta chain, especially DRbeta71, in the association between ulcerative colitis and HLA. However, this does not exclude the contribution of other parts of the molecule and other immunoregulatory genes.

Adult↗
PubMed1999

HLA class II homozygosity confers susceptibility to common variable immunodeficiency (CVID).

Most cases of CVID occur sporadically, but familial cases do also occur and 15% of the patients with the disease have first degree relatives with IgA deficiency (IgAD). Our purpose was to study CVID association with HLA class II alleles and to ascertain whether this disease shares a common genetic background with IgAD in our population. Patients with CVID (n = 42), were typed using gene amplification and sequence-specific oligonucleotide probing for HLA-DRB1, DRB3, DQA1 and DQB1 loci and their typing compared with that of 96 IgAD and 334 healthy controls. We observed a positive association between non-Asp residues at position 57 of the HLA-DQbeta chain and CVID, although much weaker than in IgAD. Further, we found an association between CVID and homozygosity for genes encoding HLA class II molecules, especially HLA-DQ, not seen in IgAD. The data support the hypothesis that a restricted diversity of HLA class II molecules may contribute to susceptibility to CVID.

Alleles↗
PubMed1999

Ventilatory compensation for inspiratory resistive loads during anaesthesia with halothane or isoflurane.

We have analysed the ventilatory response to sustained inspiratory resistive loads in 14 patients, while awake and during halothane (n = 7) or isoflurane (n = 7) anaesthesia. Patients breathed halothane or isoflurane in oxygen at 1.2 minimum alveolar concentration (MAC). Inspiratory resistances of 0, 12 and 37 cm H2O litre-1 s were applied. Tidal volume (VT) was maintained with the greater loads. At the greatest resistance, a significant reduction in minute ventilation occurred in both awake (-18.9%) and anaesthetized states, with both halothane (-10.4%) and isoflurane (-14.5%). Ventilatory frequency decreased significantly from mean 14.6 (SD 4.7) to 12.5 (4.3) bpm in the awake state and during anaesthesia, with increasing inspiratory resistance (29.5 (3.6) to 23.7 (7.2) bpm and 25.8 (3.3) to 23.4 (4.0) bpm, respectively, for halothane and isoflurane) because inspiratory time (TI) was significantly longer (P < 0.01). End-tidal PCO2 increased by 0.3 kPa, on average, from baseline to the highest level of resistance (P < 0.01). Inspiratory occlusion pressure at 100 ms increased significantly with increased loading in all situations (P < 0.001). We found a similar pattern of ventilatory adaptation to sustained inspiratory flow resistive loads both in awake and anaesthetized states. VT was maintained at increased loads because of an increase in inspiratory neuromuscular output and inspiratory duration.

Adolescent↗
PubMed1999

Preliminary study of the incidence of disomy in sperm fractions after MicroSort flow cytometry.

Using triple colour fluorescent in-situ hybridization (FISH) we have evaluated, on a blind basis, the disomy level for chromosome 21 and the sex chromosomes in flow cytometric sorted sperm samples. There were no statistically significant differences in the disomy rates when comparing the sorted samples (either for X- or Y-bearing spermatozoa) with non-sorted samples. There were no diploid spermatozoa observed in any sample group after MicroSort processing.

Adult↗
PubMed1999

[A possibility of central diffusion during stellate ganglion blockade: "the sheath of the spinal rachidian nerve"].

Stellate ganglion block is a common treatment for neuropathic pain. The technique is not without potentially severe complications when a paratracheal approach is used. A 33-year-old woman complained of atypical facial pain of 15 years' duration with pain intensity of 6 to 8 on a visual analog scale and no pain-free periods upon use of inadequate analgesia. One minute after performing a second stellate ganglion block the patient showed signs of apnea and paralysis of the upper extremities and face, with no involvement of oculomotor muscles or the lower extremities, and no loss of consciousness. Assisted ventilation was started. Signs and symptoms resolved fully after 15 minutes. A few days later, the patient reported having perceived paresthesia in the affected zone during the procedure. Central spread of a portion of local anesthetic by way of the spinal nerve sheath toward the subarachnoid space may cause partial cervical and basal nuclear blockade. Signs would be apnea, involvement of the upper extremities and facial muscles, although paresthesia during the injection is the only evidence supporting this hypothesis. Bone contact and negative aspiration while performing a stellate ganglion block do not guarantee avoidance of complications.

Adult↗
PubMed1999

Confirmation of diagnosis in preimplantation genetic diagnosis (PGD) through blastocyst culture: preliminary experience.

Three cases of preimplantation genetic diagnosis (PGD) (two for sexing and one for aneuploidy screening) are presented. Embryo biopsy was performed at day 3 and diagnosis was established with fluorescent in situ hybridization (FISH). Embryos not used for replacement were cultured in sequential media for blastocyst development. Blastocyst rate was 39.3 per cent. Confirmations of diagnosis were established with FISH in blastocysts and arrested embryos. Mosaicism was observed in 7/8 blastocysts (mean number of cells analysed: 55.5) and 5/8 arrested embryos. The percentage of abnormal cells was 17.1 per cent for blastocysts and 54 per cent for arrested embryos. Polypoid cells were observed in 4/8 blastocysts. Confirmation of diagnosis at the blastocyst stage is a useful tool in PGD.

Aneuploidy↗
PubMed1998

Atherogenic concentrations of native low-density lipoproteins down-regulate nitric-oxide-synthase mRNA and protein levels in endothelial cells.

The nitric oxide synthase family of proteins is the unique class of mammalian enzymes that metabolizes L-arginine to form nitric oxide (NO). The atherogenic action of low-density lipoproteins (LDL) may be mediated, in part, by its effects on endothelial-derived nitric oxide. To determine whether native LDL (nLDL), at atherogenic concentrations, are capable of modulating NO synthase expression, we treated human umbilical vein endothelial cells with increasing concentrations of human nLDL (0-240 mg cholesterol/dl) for various time periods (2-48 h). Northern and western blot analyses indicate that both endothelial NO-synthase mRNA and protein are down-regulated by atherogenic concentrations of nLDL (180 and 240 mg cholesterol/dl) after 48 h of incubation. Cycloheximide and actinomycin D experiments suggest that this down-regulation operates at a transcriptional level. Additionally, treatment of the cells with high-density lipoproteins, at human physiological concentrations (45 mg cholesterol/dl), does not appear to alter the expression of endothelial NO synthase which seems to indicate that nLDL affect the gene transcription rate by a specific and concentration-dependent mechanism. These findings may have important implications because they provide a novel mechanism by which hypercholesterolemia induces early changes on endothelial cells that could have pathophysiological significance in the atherosclerotic process.

Arteriosclerosis↗
PubMed1998

Cre expression in primary spermatocytes: a tool for genetic engineering of the germ line.

Transgenic mice were generated expressing a testicular Cre recombinase driven by promoter sequences derived from the gene encoding Synaptonemal Complex Protein 1 (Sycp1), expressed at an early stage of the male meiosis (leptotene to zygotene). Recombination at target LoxP sites was examined during germinal differentiation in mice harboring Sycp1-Cre and a second transgene where LoxP sites flank either the beta geo coding region, the Pgk1 promoter, or a tk-neo cassette inserted into the Rxr alpha locus. The LoxP-flanked transgenes were stably maintained in the somatic tissues of the double transgenic animals, as well as in the progeny of the females. Mice born after mating the double-transgenic males with normal females showed extensive deletions of the LoxP-flanked sequences. When the males were hemizygous for the Sycp1-Cre transgene, the deletions were observed even in the fraction of the offspring which had not inherited the Cre gene, thus demonstrating that expression occurred in the male parent during spermatogenesis. The high efficiency of excision at the LoxP sites makes the Sycp1-Cre transgenic males suitable for evaluating the role of defined gene functions in the germinal differentiation process.

Animals↗
PubMed1998

Recurrent in vitro fertilization failure evaluated by fluorescence in situ hybridization: a case report.

OBJECTIVE: To present a case of IVF failure evaluated by fluorescence in situ hybridization (FISH). DESIGN: Case report. SETTING: Research university laboratory and clinical IVF laboratory. PATIENT(S): An infertile couple with recurrent IVF failure. INTERVENTION(S): Fluorescence in situ hybridization study of the complete cohort of "zygotes" obtained at the third IVF attempt. MAIN OUTCOME MEASURE(S): Fluorescence in situ hybridization studies of chromosomes X, Y, 13, 18, and 21. RESULT(S): All the recovered putative zygotes were abnormal for the expected ploidy, presumably as a result of abnormal oocytes. CONCLUSION(S): Fluorescence in situ hybridization techniques represent a promising approach to analyze zygotes that fail to divide normally in vitro and eggs that fail to become fertilized. In cases of recurrent IVF failure, the results of FISH could be used to counsel couples and thus to help them choose among methods other than IVF for assisted reproduction.

Adult↗
PubMed1998

Influence of chronic alcohol abuse and liver disease on hepatic aldehyde dehydrogenase activity.

Alcohol metabolism results in the production of acetaldehyde, a compound that is much more toxic than ethanol itself. Hepatic aldehyde dehydrogenase (ALDH) is the main enzymatic system responsible for acetaldehyde clearance from the hepatocyte. The objective of this study was to determine the modifications in ALDH activity due to chronic alcohol abuse and liver disease. ALDH activity was determined in samples of liver tissue from 69 alcoholic and 82 nonalcoholic subjects, with and without liver disease. According to the results of liver pathology examination, alcoholic patients were classified into the following groups: controls, with no liver disease (group 1), noncirrhotic liver disease patients (group 2), and cirrhotics (group 3). Nonalcoholic subjects were categorized, using the same criteria, into groups 4, 5, and 6, respectively. ALDH activity was determined spectrophotometrically at two substrate concentrations: 18 mM for total activity and 180 microM for low Km activity. High Km activity was calculated by subtracting the low Km activity value from that of total ALDH activity. Results obtained in each group were expressed as the mean +/- SD of mU of g of wet weight. There were no significant differences when the total ALDH activity from the alcoholic and the nonalcoholic patients with a similar degree of liver pathology were compared: group 1, 1257 +/- 587 vs. group 4, 1328.1 +/- 546.2 (p: NS); group 2, 919.1 +/- 452.4 vs. group 5, 753.5 +/- 412 (p: NS); and group 3, 430.2 +/- 162.4 vs. group 6, 473.2 +/- 225.3 (p: NS). On the other hand, total ALDH activity was significantly lower in cirrhotics than in controls, both among alcoholics (p < 0.01) and among nondrinkers (p < 0.05). The low Km activity was severely reduced in cirrhotics, both alcoholics and nonalcoholics (p < 0.01). High Km activities in cirrhotic patients were low, compared to controls, both in alcoholics and nonalcoholics, although the difference was nonsignificant. The results of the present study suggests that chronic alcohol abuse does not depress ALDH activity. A reduction in the ALDH activity detected in patients with severe liver disease (cirrhotics) was clearly a consequence of liver damage. This reduction was due mainly to a decrease of the low Km ALDH activity, but a trend to a decrease in the high Km ALDH activity was also detected.

Adult↗
PubMed1998

[The contribution of cognitive evoked potentials to knowledge of mechanisms on the Stroop test].

The Stroop test is based on interference between reading and naming of incongruent color words. To decide whether this conflict was of perceptual or motor origin, event-related potentials were simultaneously recorded. Since the components of these potentials are dependent on the progression of information processing, their changes related with the nature of the stimulation should provide information about the mechanisms underlying the conflict. Evoked potentials were recorded from three midline leads in 18 healthy subjects during reading and naming tasks. The 216 stimulations were the words "red, green and blue" presented in either a congruent or incongruent color, or in a neutral color. The behavioral Stroop effect did not affect the P300 latency, suggesting that the conflict occurs in the motor system. This was supported by the presence of a premotor negativity for incongruent stimulations, occurring between 400 and 205 ms before button press, and present in the naming condition only. Moreover, for the two conditions, congruent stimulations evoked positive potentials between 260 and 310 ms at the level of the occipital lead for reading and at the level of the frontal lead for naming. The possibility of an interaction of specialized channels for stimulation analysis at an early level is raised.

Adolescent↗
PubMed1998

FISH preimplantation diagnosis of chromosome aneuploidy in recurrent pregnancy wastage.

PURPOSE: Our purpose was to detect aneuploidy for chromosomes 13, 16, 18, 21, 22, X, and Y in preimplantation embryos from patients with a history of unexplained recurrent miscarriage. METHODS: Three patients with a history of unexplained recurrent spontaneous abortion were included in this study. Embryos were biopsied at the eight-cell stage, individually fixed on slides, and processed for fluorescent in situ hybridization (FISH). A multiple FISH protocol for seven chromosomes pairs (13, 16, 18, 21, 22, X, and Y) has been developed. RESULTS: A total of 39 embryos was studied with the multiple FISH protocol developed. Successful analysis of the biopsied embryos was achieved within the time limits usually allowed in a preimplantation diagnosis program. Analysis of the blastomeres showed that 17 embryos were chromosomally normal for the probes used, 16 embryos were aneuploid, and in 6 embryos no informative results were obtained. CONCLUSIONS: In the patients studied, a large proportion of embryos (41%) exhibited chromosomal abnormalities for the probes used. Preimplantation diagnosis to screen for chromosome abnormalities could be a feasible approach to improve the possibility of successful pregnancy in these couples.

Abortion, Habitual↗
PubMed1998

Increased chromosome abnormalities in human preimplantation embryos after in-vitro fertilization in patients with recurrent miscarriage.

Recurrent miscarriage is a pathological condition induced by maternal and embryonic causes. This paper describes a prospective study to determine the real incidence of aneuploidy for autosomes 13, 16, 18, 21, 22, and gonosomes in preimplantation human embryos obtained from patients with recurrent pregnancy loss after ovarian stimulation in an IVF-ET programme. Our results indicate that aneuploidy for the chromosomes analysed are abnormally higher in embryos obtained after IVF from recurrent abortion patients (58%) compared to non-recurrent abortion patients undergoing IVF. Furthermore, monosomies are six times more frequent than trisomies (47:8) in preimplantation embryos from recurrent abortion patients. Based on the present study, preimplantation genetic diagnosis (PGD) of embryos obtained from patients with recurrent miscarriage could prove advantageous in diagnosing abnormal embryos and selecting normal embryos for transfer.

Abortion, Habitual↗
PubMed1998

Chromosome 21 disomy in the spermatozoa of the fathers of children with trisomy 21, in a population with a high prevalence of Down syndrome: increased incidence in cases of paternal origin.

Between April 1991 and December 1994, epidemiological studies detected a population with a high prevalence of Down syndrome in El Vallès, Spain. Parallel double studies were carried out to determine the parental and the meiotic origins of the trisomy 21, by use of DNA polymorphisms, and to establish the incidence of disomy 21 in the spermatozoa of the fathers of affected children, by use of multicolor FISH. Results show that the overall incidence of chromosome 21 disomy in the fathers of affected children was not significantly different from that in the control population (0.31% vs. 0.37%). However, analysis of individual data demonstrates that two cases (DP-4 and DP-5) with significant increases of disomy 21 (0. 75% and 0.78% vs. 0.37%) correspond to the fathers of the two individuals with Down syndrome of paternal origin. DP-5 also had a significant increase of sex-chromosome disomies (0.69% vs. 0.37%) and of diploid spermatozoa (1.13% vs. 0.24%).

Chromosome Aberrations↗
PubMed1998

Efficiency of MicroSort flow cytometry for producing sperm populations enriched in X- or Y-chromosome haplotypes: a blind trial assessed by double and triple colour fluorescent in-situ hybridization.

Using fluorescent in-situ hybridization (FISH) we have evaluated, on a blind basis, the efficiency of flow cytometry to separate human X- and Y-chromosome bearing spermatozoa. Our data demonstrate that human spermatozoa can be sorted to a purity of 80-90% for X spermatozoa and of 60-70% for Y spermatozoa. Our results using triple FISH fully agree with the sorting treatment used in each case and corroborate the efficiency of the flow sorting technique for sperm sex selection. In these limited samples (200-500 sperm/donor), the frequencies of disomic or diploid spermatozoa were not increased when comparing the sorted samples with unselected samples or with our control series.

Cell Separation↗