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Biomedical subjects

C Miquel

Publications and source records attributed to C Miquel.

At least 19 recordsLinked to original sources
PubMed1996

Establishment and characterization of cell line LSV5 that retains the altered adhesive properties of human junctional epidermolysis bullosa keratinocytes.

Herlitz junctional epidermolysis bullosa (H-JEB) is characterized by hampered expression of the adhesion ligand laminin-5. Thus far, analysis of the processes underlying the epithelial-mesenchymal dysadhesion marking this disease has been limited by the reduced growth and adhesive capabilities of the epithelial cells derived from H-JEB patients. To overcome these difficulties, we used SV40 virus to immortalize H-JEB keratinocytes with a homozygous nonsense mutation in the gene that encodes the gamma2 chain of laminin-5. Cell lines (LSV) derived from infected keratinocytes maintain a stable karyotype, grow independent of 3T3 feeder layers and are not tumorigenic. Further analysis of clone LSV5 showed an increased secretion of laminin-6 and fibronectin compared to normal keratinocytes. Similar to parental H-JEB keratinocytes, these cells regenerate stratified epidermis in vitro and, in in vivo models, they synthesize a basement membrane lacking laminin-5. LSV cells show hypermotility and reduced adhesive properties resulting from an incomplete association with the underlying culture substrate. These results demonstrate that LSV5 cells retain the pathologic phenotype of H-JEB keratinocytes and can serve as a model system to study the adhesion processes mediated by laminin-5.

3T3 Cells↗
PubMed1996

The Kleinian Psychoanalytic Diagnostic Scale (revised version): presentation and study of reliability.

The Kleinian Psychoanalytic Diagnostic Scale (KPDS) is a psychodiagnostic instrument of assessment based on the psychoanalytical theory of object relations. It was created in order to introduce an intrapsychic and relational dimension into the clinical research on and epidemiology of psychiatric diagnosis. It consists of 15 subscales grouped into the following four dimensions: "Ego Abilities'; "Projective Identification'; "Paranoid-Schizoid'; and "Depressive'. These dimensions constitute different, relatively stable aspects of the mental life of the subject, their demarcation and description permitting the obtention of a chart and profile of the intrapsychic and relational structure. Following several free, unstructured interviews the scale is assessed on the basis of what the subject says and what the rater may detect in the relationship. The inter-rater reliability of the scale, its stability over a time lapse, as well as its internal consistency have all been shown to be high.

Adolescent↗
PubMed1995

Cloning of the laminin alpha 3 chain gene (LAMA3) and identification of a homozygous deletion in a patient with Herlitz junctional epidermolysis bullosa.

Laminin 5 and laminin 6 are basement membrane proteins synthesized by the basal cells of stratifying squamous epithelia. Altered expression of laminin 5 has been associated with Herlitz junctional epidermolysis bullosa (H-JEB), a severe epidermal blistering disorder inherited as an autosomal recessive disease. We have isolated cDNA clones encoding the alpha 3 chain of laminin 5 and searched for mutations in the LAMA3 gene in H-JEB patients. In one H-JEB family, an affected individual exhibited drastically reduced immunoreactivity to antibodies directed against the alpha 3 chain of laminin 5 and an impaired expression of the corresponding mRNA transcripts. RT-PCR analysis of mRNA extracted from the proband's keratinocytes identified a homozygous single basepair deletion in the transcripts encoding the laminin alpha 3A and alpha 3B isoforms. The mutation causes a frameshift and premature termination codon in both alleles of the LAMA3 gene. Inheritance of the clinical H-JEB phenotype was consistent with the segregation of the mutated allele in the family. We also report the identity of the alpha chains of laminin 5 and epiligrin and provide evidence that LAMA3 transcripts are distinct from the laminin 6 alpha chain mRNA.

3T3 Cells↗
PubMed1995

Integrin beta 4 mutations associated with junctional epidermolysis bullosa with pyloric atresia.

Pyloric atresia associated with junctional epidermolysis bullosa (PA-JEB), is a rare inherited disorder characterized by pyloric stenosis and blistering of the skin as primary manifestations. We demonstrate that in one PA-JEB patient the disease resulted from two distinct mutations in the beta 4 integrin gene alleles. The paternal mutation consists of a one base pair deletion causing a shift in the open reading frame, and a downstream premature termination codon. The maternal mutation occurs in a donor splice site, and results in in-frame exon skipping involving the cytoplasmic domain of the polypeptide. Our results implicate mutations in the beta 4 integrin gene in some forms of PA-JEB.

Alleles↗
PubMed1995

Identification of a homozygous one-basepair deletion in exon 14 of the LAMB3 gene in a patient with Herlitz junctional epidermolysis bullosa and prenatal diagnosis in a family at risk for recurrence.

Herlitz junctional epidermolysis bullosa, a severe epidermal blistering disorder, is inherited in an autosomal recessive manner. It has recently been shown that, in kindreds with junctional epidermolysis bullosa, the disorder results from mutations in the gamma 2 chain of laminin-5, a basement membrane protein synthesized by the basal cells of stratifying squamous epithelia. In this report we describe a mutation identified in the beta 3 chain gene of laminin-5 in a family with Herlitz junctional epidermolysis bullosa. The disease is caused by a homozygous deletion of 1 bp that leads to a frameshift and premature termination codon. The segregation of the mutated allele in the family is consistent with the pathogenic role of the mutation. We also report a direct DNA-based prenatal exclusion of Herlitz junctional epidermolysis bullosa in a pregnancy at risk using a chorionic villus biopsy and allele-specific oligomer hybridization from polymerase chain reaction-amplified genomic DNA.

Base Sequence↗
PubMed1994

Herlitz junctional epidermolysis bullosa keratinocytes display heterogeneous defects of nicein/kalinin gene expression.

Previous studies have correlated the Herlitz junctional epidermolysis bullosa (H-JEB) to an altered expression of the basement membrane component nicein/kalinin. This heterotrimeric glycoprotein appears to be present in H-JEB tissues in an abnormal form, because a number of antibodies specific to the protein either do not react with or weakly stain the epidermal basement membranes of most of the patients. With cDNA probes encoding each subunit of nicein and polyclonal antibodies raised against bacterial fusion polypeptides corresponding to the individual chains of the protein, we have molecularly analyzed the expression of nicein in H-JEB tissues and cultured keratinocytes. By immunohistochemistry, Northern blot, and protein analysis, we show a defective synthesis of one of the nicein subunits in six cases of H-JEB from five different consanguineous families. In two patients, the disease correlates with an impaired synthesis of the nicein B2 (nic B2) chain, in three others with that of the B1 (nic B1) chain, and in a sixth patient with that of the heavy A (nic A) chain. In this report, we thus demonstrate that H-JEB is a genetically heterogeneous disease and we provide strong evidence that the genes of nicein are the candidates for this genodermatosis.

Blotting, Northern↗
PubMed1992

Retinoic acid receptor isoform RAR gamma 1: an antagonist of the transactivation of the RAR beta RARE in epithelial cell lines and normal human keratinocytes.

The diversity of isoforms of retinoic acid (RA) receptors (RARs) and of DNA sequences of retinoic acid-responsive elements (RAREs) suggests the existence of selectivities in the RAR/RARE recognition or in the subsequent gene modulation. Such selectivities might be particularly important for RAREs involved in positive feedback, eg. the RAR beta RARE. In the present work we found that in several epithelial cell lines, reporter constructs containing the RAR beta RARE linked to the HSV-tk promoter were transactivated in the presence of RA by endogenous RARs and co-transfected RAR alpha 1 and RAR beta 2 isoforms, but not by RAR gamam 1. On the contrary, this latter isoform behaved towards the RAR beta RARE as an inhibitor of the transactivation produced by endogenous RARs and by cotransfected RAR alpha 1 and RAR beta 2. RAR gamma 1 also behaved as an antagonist of the transactivation produced by cotransfected RXR alpha. The natural RAR beta gene promoter or RAR beta RARE tk constructs were not activated by the endogenous receptors of normal human keratinocytes (NHK), which are known to contain predominantly RAR gamma 1. It was, however, possible to activate to a certain extent RAR beta RARE-reporter constructs in NHK by co-transfecting RAR alpha 1, RAR beta 2 or RXR alpha. The antagonist behavior of RAR gamma 1 towards the RAR beta RARE may explain why in certain cell types such as keratinocytes, RAR beta is neither expressed nor induced by RA.

Animals↗
PubMed1992

Surface roughness of finished composite resins.

This study evaluated the results of polishing composite resin by using the following finishing and polishing techniques: Arkansas stone burs; eight-blade tungsten-carbide burs; diamond burs; aluminum-oxide disks; no polishing; and 12- and 30-blade tungsten-carbide burs. The results were compared to ascertain which technique delivers the smoothest surface. The study was done with 120 class V restorations on extracted human teeth distributed in two groups (I and II) of 60 restorations each. Group I teeth samples were filled with microfilled composite resin and Group II with a hybrid composite resin. Readings were made with a profilometer to evaluate the final polishing. The conclusions from the results of the study were that microfilled composite resins provided a better finish when treated with aluminum-oxide disks. These results were statistically significant (p < 0.001). When hybrid composites were used the control group recorded the lowest values.

Aluminum Oxide↗
PubMed1991

Determination of retinoid activity by an enzyme-linked immunosorbent assay.

In normal human keratinocytes, retinoic acid suppresses the expression of the plasma membrane associated enzyme transglutaminase (TGm) at the pretranslational level. This finding led us to develop an enzyme-linked immunosorbent assay (ELISA) for the evaluation of the biological activity of retinoids, i.e., natural and synthetic derivatives of vitamin A. In this assay, keratinocytes are cultured in a 96-well cluster in the presence of different retinoid concentrations. The expression of TGm is then quantified, without any extraction or purification step, using a TGm-specific monoclonal antibody and a peroxidase-conjugated secondary antibody. The dose-response curves obtained show this ELISA to be a sensitive and reproducible assay to determine the potency of retinoids.

Animals↗
PubMed1990

Deficiency in catalase activity correlates with the appearance of tumor phenotype in human keratinocytes.

Biopsies isolated from various human stratified epitheliomas and cultures of the associated fibroblasts exhibit a breakdown in catalase activity (70 to 95%). We report here that primary human cultures of keratinocytes and various immortalized keratinocyte cell lines differ from one other in their catalase activity. Moreover, deficient catalase activity appears to be related to the intensity of tumor phenotype expression. Since catalase activity in cell lines transformed in vitro is not as weak as activity observed in cell lines isolated from tumors, catalase deficiency may follow the successive steps of tumor progression.

Acatalasia↗
PubMed1980

[Hypokalemic periodic paralysis. Report of two cases (author's transl)].

The familial periodic hypokalemic paralysis is an infrequent disease characterized by paralytic attacks of sudden appearance affecting the muscles of the trunk and limbs. There is a marked hypokalemia during the paralytic episodes of the disease, and a family history in 80 percent of the cases. The differential diagnosis includes hyperthyroidism with periodic paralysis, congenital paramyotony and adynamia episodica hereditaria. Two typical cases of hypokalemic periodic paralysis are presented, with biological, electrophysiological, clinical, and ultrastructural pictures characteristics of the disease. The clinical manifestations of both patients are discussed, stressing the diagnostic importance of the electrophysiological study during the insulin test, and the interest of the histologic and ultrastructural studies. The spectacular response during the acute episodes to the intravenous perfusion of potassium salts, and the usefulness of the acetazolamide administration to prevent the paralytic episodes are emphasized.

Adolescent↗