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Biomedical subjects

F Vidal

Publications and source records attributed to F Vidal.

At least 55 records · Page 3Linked to original sources
PubMed1999

Pseudomonas aeruginosa bacteremia in patients infected with human immunodeficiency virus type 1.

A prospective analysis of 43 episodes of Pseudomonas aeruginosa bacteremia in HIV-1-infected subjects was performed and the results compared with the incidence and outcome of Pseudomonas aeruginosa bacteremia in other high-risk patients, such as transplant recipients, leukemia patients, or patients hospitalized in the intensive care unit. The incidence of bacteremia/fungemia as a whole and of gram-negative and Pseudomonas aeruginosa bacteremia in particular was greater in HIV-1-infected subjects than in the unselected general population admitted. In contrast, the incidence of Pseudomonas aeruginosa bacteremia in HIV-1-infected patients did not differ from that in patients with other high-risk conditions. In patients with HIV-1 infection, independent risk factors for presenting Pseudomonas aeruginosa bacteremia were nosocomial origin (OR, 2.7; 95% CI, 1.3-5.7), neutropenia (OR, 2.7; 95% CI, 1.07-6.8), previous treatment with cephalosporins (OR, 3.6; 95% CI, 1.1-11.6), and a CD4+ cell count lower than 50 cells/mm3 (OR, 3.1; 95% CI, 1.7-8.6). Primary bacteremia and pneumonia were the most common forms of presentation. Fourteen (33%) patients died as a consequence of the bacteremia. The presence of severe sepsis (OR, 17.5; 95% CI, 3.2-68) and the institution of inappropriate definitive antibiotic therapy (OR, 2.7; 95% CI, 1.1-13) were independently associated with a poor outcome. One year after the development of bacteremia, only eight (19%) patients remained alive.

AIDS-Related Opportunistic Infections↗
PubMed1999

In vitro fertilization plus preimplantation genetic diagnosis in patients with recurrent miscarriage: an analysis of chromosome abnormalities in human preimplantation embryos.

OBJECTIVE: To analyze the incidence of numeric chromosomal abnormalities in preimplantation embryos from women with unexplained recurrent miscarriage (RM) so as to seek an etiology and to determine whether the use of IVF may be indicated to treat these cases. DESIGN: Prospective controlled study. SETTING: University laboratory of reproductive genetics and a tertiary referral center for infertility. PATIENT(S): Nine women with a mean (+/-SD) of 3.9 +/- 0.6 RMs who were undergoing IVF and preimplantation genetic diagnosis, and a control group of young (n = 10) and older (n = 6) patients who were undergoing preimplantation genetic diagnosis because of sex-linked diseases. INTERVENTION(S): In vitro fertilization, embryo culture for 72 hours, blastomere biopsy, and analysis of chromosomes 13, 16, 18, 21, 22, X, and Y with the use of fluorescent in situ hybridization. Transfer of chromosomally normal embryos into the uterus. MAIN OUTCOME MEASURE(S): Numeric chromosomal abnormalities in human embryos. RESULT(S): Sixty-six embryos from patients with RM were compared with 62 embryos from young patients and 41 embryos from older patients. There was a significant increase in the rate of abnormal embryos in the patients with RM and the older patients compared with the controls. Abnormalities in most of the chromosomes studied were higher in the RM group than in the control group, especially those affecting chromosome 13. CONCLUSION(S): There was an increase in numeric chromosomal abnormalities in preimplantation embryos from women with RM that could be the cause of infertility in many couples with unexplained RM. The use of IVF in such circumstances may be indicated if successful preimplantation genetic diagnosis is added to the procedure.

Abortion, Habitual↗
PubMed1999

Screening for abnormalities of chromosomes X, Y, and 18 and for diploidy in spermatozoa from infertile men participating in an in vitro fertilization-intracytoplasmic sperm injection program.

OBJECTIVE: To evaluate the frequency of disomy (for chromosomes X, Y, and 18) and of diploidy in the spermatozoa of infertile men undergoing intracytoplasmic sperm injection (ICSI). DESIGN: Prospective analysis of sperm nuclei by fluorescence in situ hybridization (FISH). SETTING: University-affiliated IVF-ICSI program. PATIENT(S): Semen samples from 19 patients participating in an IVF-ICSI program. INTERVENTION(S): Semen samples were analyzed and prepared for FISH. MAIN OUTCOME MEASURE(S): Semen parameters were evaluated. The frequency of disomy for chromosomes X, Y, and 18 and the frequency of diploidy were analyzed by FISH. RESULT(S): A total of 9,373 spermatozoa from 19 infertile patients were analyzed and compared with spermatozoa from a control group of 5 healthy men. No differences in the frequency of disomy 18 were found, but statistically significant differences in the incidence of sex chromosome disomy and of diploidy were observed. CONCLUSION(S): The study of sperm nuclei by FISH is useful to improve genetic counseling in infertile patients selected for ICSI.

Adult↗
PubMed1999

Effect of the irrelevant location of the response signal on choice reaction time: an electromyographic study in humans.

Choice reaction time (RT) is shorter when the stimulus corresponds spatially to the response than when the stimulus does not, even when the stimulus location is irrelevant to the task. We used electromyographic measures to document that this effect is the result of a response conflict. The activity of the prime movers of two alternative responses was recorded during the performance of a visual RT task in which the irrelevant spatial correspondence between the stimuli and the responses was varied. Only the premotor component of RT was affected by the stimulus-response correspondence. Correct trials were distinguished according to whether or not the activation of the prime mover involved in the required response was preceded by an activation of the prime mover involved in the alternative response. Double muscular activation trials were more numerous for noncorresponding than for corresponding stimulus-response associations. Furthermore, these trials yielded longer RTs than the single muscular activation trials.

Adult↗
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↗