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L Bonilla

Publications and source records attributed to L Bonilla.

5 recordsLinked to original sources
PubMed2003

Fragile-X syndrome and skewed X-chromosome inactivation within a family: a female member with complete inactivation of the functional X chromosome.

Fragile X syndrome is the most common form of inherited mental retardation. It is caused by the increase in length of a stretch of CGG triplet repeats within the FMR1 gene. A full mutation (> 200 repeats) leads to methylation of the CpG island and silencing of the FMR1 gene. We present here two sisters that are compound heterozygotes for a full mutation and a 53 repeat intermediate allele, one of them showing mental retardation and clinical features of an affected male (speech delay, hyperactivity, large ears, prominent jaw, gaze aversion), while the other is borderline normal (mild delay). Southern blot and FMRP expression analysis showed that the sister with mental retardation had the normal FMR1 gene totally methylated and no detectable protein, while her sister had 70% of her cells with the normal FMR1 gene unmethylated and normal FMRP levels. We found that the observed phenotypic differences between both sisters who are cytogenetically normal, are caused by extreme skewed X-chromosome inactivation. Analysis of the extended family showed that most of the other female family members that carry a pre-mutation or a full mutation showed some degree of skewing in their X-chromosome inactivation. The presence of several family members with skewed X inactivation and the direction and degree of skewing is inconsistent with a mere selection during development, and suggests a genetic origin for this phenomenon.

Adolescent↗
PubMed2001

Eosinophil peroxidase oxidation of thiocyanate. Characterization of major reaction products and a potential sulfhydryl-targeted cytotoxicity system.

Although the pseudohalide thiocyanate (SCN(-)) is the preferred substrate for eosinophil peroxidase (EPO) in fluids of physiologic halide composition, the product(s) of this reaction have not been directly identified, and mechanisms underlying their cytotoxic potential are poorly characterized. We used nuclear magnetic resonance spectroscopy (NMR), electrospray ionization mass spectrometry, and quantitative chemical analysis to identify the principal reaction products of both the EPO/SCN(-)/H(2)O(2) system and activated eosinophils as roughly equimolar amounts of OSCN(-) (hypothiocyanite) and OCN(-) (cyanate). Red blood cells exposed to increasing concentrations of OSCN(-)/OCN(-) are first depleted of glutathione, after which glutathione S-transferase and glyceraldehyde-3-phosphate dehydrogenase then ATPases undergo sulfhydryl (SH) reductant-reversible inactivation before lysing. OSCN(-)/OCN(-) inactivates red blood cell membrane ATPases 10-1000 times more potently than do HOCl, HOBr, and H(2)O(2). Exposure of glutathione S-transferase to [(14)C]OSCN(-)/OCN(-) causes SH reductant-reversible disulfide bonding and covalent isotope labeling. We propose that EPO/SCN(-)/H(2)O(2) reaction products comprise a potential SH-targeted cytotoxic system that functions in striking contrast to HOCl, the highly but relatively indiscriminantly reactive product of the neutrophil myeloperoxidase system.

Adenosine Triphosphatases↗
PubMed2000

Neglected traumatic posterior dislocations of the shoulder: controversies on indications for treatment and new CT scan findings.

We report seven missed traumatic posterior dislocations of the shoulder in six patients. In all seven shoulders, anteroposterior radiographs did not provide the diagnosis in the emergency room after the trauma (epileptic seizure in four patients) and diagnosis was delayed for at least 24 h. The final diagnosis was reached by clinical suspicion and computed tomography (CT) scan of the seven shoulders. Two shoulders were treated by closed reduction and three were treated by closed reduction and percutaneous pinning, although four of these five shoulders presented a defect in the humeral head involving 20%-25% of the articular surface. Two shoulders dislocated for more than 6 months were treated according to Mc Laughlin's technique modified by Hawkins instead of an arthroplasty. At a minimum follow-up of 2 years and 2 months, the functional results according to Hawkins were good in all seven shoulders. There was no recurrence of the dislocation in any patient. Radiographs showed mild degenerative changes. The establishment of indications for treatment, based on the proportion of articular surface of the humeral head involved and the time of evolution of the dislocation, needs more clinical or experimental evidence. In epileptic patients, strict control of medication is of the utmost importance.

Adult↗