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Biomedical subjects

M Guitart

Publications and source records attributed to M Guitart.

29 records · Page 2Linked to original sources
PubMed1996

FRAXE mutation analysis in three Spanish families.

Very little is known about the phenotype of FRAXE-positive individuals and the relation between the genotype/phenotype and genotype/ cytogenetic expression. We describe three families with normal and mildly affected individuals and a severely retarded male expressing fragility at the FRAXE locus or presenting different expansions at the CGG FRAXE triplet. In addition, we analyze the FRAXE mutation in sperm DNA from a retarded male carrier with a handicapped daughter expressing fragility at the FRAXE locus. Mental status in FRAXE individuals is highly variable and, although mild mental retardation is observed in most cases, several carrier males are apparently normal. It seems that methylation is not as strictly associated with size of CGG triplets in the FRAXE locus as in FRAXA, and it is possible that normal carrier individuals with fully methylated increments in lymphocytes have a certain proportion of unmethylated alleles in the critical (i.e., neural) tissues, FRAXE mutation is apparently similar to FRAXA in that males with somatic large methylated increments are carriers of small unmethylated ones in germinal cells.

Adolescent↗
PubMed1994

Detection of aberrant DNA methylation in unique Prader-Willi syndrome patients and its diagnostic implications.

Most patients with Prader-Willi syndrome have a deletion of 15q11-13 or maternal uniparental disomy for chromosome 15. The shortest region of deletion overlap is presently defined by the gene for the small nuclear ribonucleoprotein N (SNRPN). We have investigated the integrity of SNRPN as well as the methylation status of D15S63 (PW71) in two patients with apparently normal chromosomes 15 of biparental origin. SNRPN is normal in one patient and deleted in the other one. Both patients are intact at the D15S63 locus, but have an abnormal methylation pattern. These results suggest that a DNA sequence close to SNRPN determines the methylation status of D15S63 and that the methylation test does not only detect the common deletions and uniparental disomy, but other rare lesions as well.

Adolescent↗
PubMed1993

Appraisal of fluorescence in situ hybridization (FISH) techniques in prenatal diagnosis.

The reliability of FISH was appraised using probes for the X and Y chromosome and for chromosomes 12 and 18 in prenatal and adult interphase nuclei. Detection of a single hybridization spot proved to be quite reliable (80-92% positive nuclei). Detection of two hybridization spots was more difficult; percentages of nuclei showing two signals varied between 62-72%. The percentages of nuclei with the correct number of spots was higher in the metaphases occasionally found. Thus, FISH may complement but not replace cytogenetic analysis. For sex determination and for the detection of mosaicism, we suggest the use of two different probes in separate regions of the same preparation.

Amniotic Fluid↗
PubMed1987

New data on the synaptic process of Mesocricetus auratus: connecting fibers, telomere association and heterosynapsis.

The progression of the prophase-I stage in Syrian hamster spermatocytes has been studied at different ages, from 12 to 41 days after birth. Two stages, leptotene and diplotene, were identified, which had not previously been described in the Syrian hamster using spreading techniques. The most interesting observations are the presence of heterosynapses and telomere associations in 2.5% of the cells studied, and of nucleolar filaments also in 2.5%. Connecting fibers are structures that establish different types of bridges between two or three synaptonemal complexes (SCs) or between the elements of a single SC. Heterosynapses and telomere associations consist in the partial pairing of the terminal regions of non-homologous lateral elements. These phenomena can be observed both in the autosomes and in the sex chromosomes.

Animals↗
PubMedDate not supplied

Origin of trisomy 21 in Down syndrome cases from a Spanish population registry.

We have carried out a population-based study on the origin of the extra chromosome 21 in 38 families with Down syndrome (DS) offspring in El Vallès (Spain). From 1991 to 1994, a higher prevalence of DS (22.7/10000 live births, stillbirths and induced abortions) was found compared to the majority of EUROCAT registries. The distribution of trisomy 21 by origin was 88% maternal (90.6% meiosis I, 6.2% meiosis II, 3.1% maternal mosaicism), 5.6% paternal (50% meiosis I, 50% meiosis II) and 5.6% mitotic. The percentage of parental mosaicism was 2.7%. These percentages are similar to those previously reported. Recombination study revealed a maternal meiosis I genetic map of 32.68 cM (approximately one-half the length of the normal female map). Mean maternal age among non-recombinant cases involving MI errors was significantly lower (31.1 years) than among those cases showing one observable crossover (36.1 years) (P<0.05); this could support the hypothesis that 'achiasmate' chromosomes may be subject to aberrant segregation regardless of maternal age.

Abortion, Induced↗
PubMedDate not supplied

Fetal and placenta chromosome constitution in 237 pregnancy losses.

The aim of the study was to carry out cytogenetic analyses in pregnancy losses. Samples of cartilage and placenta tissue were obtained prospectively from 237 pregnancy losses of more than 16 weeks of gestation (130 stillbirths, 97 induced abortions and 10 early neonatal deaths). Cartilage culture was performed in 222 samples and placental culture was initiated in 224. The overall culture success rate was 83.5%, 72.3% in stillbirths, 97% in induced abortions and 100% in early neonatal death. An abnormal karyotype was detected in 52 cases: 6.9% in stillbirths, 43.6% in induced abortions and 20% in early neonatal deaths. The rate of discrepancy between the prenatal cytogenetic results in amniotic fluid and the post-termination karyotype was 3%. The tissue of choice for cytogenetic analysis was cartilage in induced abortions and early neonatal death, and placenta in stillbirth. The majority of cases had a chromosome abnormality: multiple congenital anomalies in 74.6%, and a single major anomaly in 9.7%.

Abortion, Induced↗
PubMedDate not supplied

[Diagnosis and treatment of the phobia due to treatment with air using nasal continuous pressure].

INTRODUCTION: The obstructive sleep apnoea syndrome (OSAS) is characterized by destructured sleep due to repeated episodes of obstruction of the superior respiratory tract during sleep. Treatment by nasal continuous positive airway pressure (n-CPAP) using air is one of the most common forms of treatment of OSAS, although some patients cannot tolerate it. One of the causes of intolerance of n-CPAP is the phobic reaction of some patients. OBJECTIVE: The objective of this study is to show that phobia is one of the causes of n-CPAP not being accepted by OSAS patients and demonstrates the efficacy of treatment by exposure in cases of phobic fear of mask. Patients and methods. We studied six patients with phobic intolerance of CPAP and established the diagnosis of phobia according to the criteria of DSM-IV. Subsequently, they were treated by real-life exposure, one of the behavior techniques most often used for phobic disorders, and consisting of exposure to the feared object under conditions in which escape or avoidance is impossible. CONCLUSION: Following the diagnosis of phobia of the CPAP mask, it was seen that treatment involving real-life exposure was effective.

Aged↗
PubMedDate not supplied

[Accidents prevalence in a group of patients with the narcolepsy- cataplexy syndrome].

INTRODUCTION: Recent studies have shown statistically that the proportion of accidents at work, at home and on the roads is greater in narcoleptic patients than in the general population. OBJECTIVE: The object of this study is to show the high prevalence of the risk of accidents in patients diagnosed as having the narcolepsy-cataplexy syndrome. PATIENTS AND METHODS: We studied a group of 35 patients of both sexes, diagnosed in the Sleep Pathology Unit of our hospital between 1994 and 1998 as having the narcolepsy-cataplexy syndrome. They filled out a questionnaire to find the prevalence of accidents. The data obtained regarding the type and number of accidents, their causes, gravity, legal and economic consequences were compared with those obtained in a group of 25 healthy subjects using the chi squared test. RESULTS: The results showed a higher risk of accidents in narcoleptic as compared with normal persons, with a statistically significant difference between the two groups. CONCLUSIONS: This study has shown the greater risk of accidents in these patients and the need for diagnosis as soon as possible so as to establish suitable treatment and thus improve their own personal safety and that of those around them.

Accidents, Traffic↗
PubMedDate not supplied

[Latent inhibition threshold in Roman high-avoidance rats: a psychogenetic model of abnormalities in attentional filter?].

INTRODUCTION: Basic research devoted to the study of the psychobiological anomalies of schizophrenia, as well as of its treatments, has used animal models in which some psychotic-like symptoms are induced by administration of psychostimulant drugs. There is, however, a growing necessity of having animal models presenting better construct validity, i.e., animal lines spontaneously showing phenotypes associated to the psychotic spectrum (for instance, enhanced sensitivity to psychostimulants, or cognitive and attentional anomalies characteristic of schizophrenic disorders). Several lines of evidence suggest that the RHA (Roman high-avoidance) rat strain presents a neurobehavioral profile which is consistent with such goals. METHODS: RHA rats were compared to Sprague-Dawley (SD) rats (as a standard control strain) for the expression of latent inhibition (in a 100-trial session of two-way active avoidance) under threshold conditions (i.e., only 15 preexposures to the conditioned stimulus were administered). RESULTS: Under such experimental conditions SD rats showed significant latent inhibition of the two-way active avoidance response (both during the first 50 trials and in the whole 100-trial session), while that attentional phenomenon did not appear in the RHA strain. CONCLUSIONS: The experimental results obtained here indicate that RHA rats display a deficit of latent inhibition at threshold conditions, an information processing (or attentional) anomaly which typically appears in schizophrenic patients. It is proposed that RHA rats might be an useful animal model for the study of vulnerability to some schizophrenic symptoms. This conclusion is supported by data that indicate that latent inhibition deficits are a characteristic attentional abnormality of these diseases.

Animals↗