Kinetics of the calcium induced stratification of human keratinocytes in vitro

In a low concentration of calcium (0.1 mM), keratinocytes form a monolayer with about 30% of cells synthesizing involucrin. After addition of calcium to the culture medium to a concentration of 1.2 mM, the monolayer stratifies within 24 h, with a preferential migration of involucrin positive keratinocytes. In the present study, we tried to determine if keratinocytes control the decision to migrate at a distinct cell cycle point. A percentage labelled mitosis (PLM) curve was constructed for keratinocytes grown in low calcium medium and values for the length of the cell cycle (47 h), S phase duration (11 h) and G2+ M period (6 h), were obtained. Monolayer cultures at 80% confluence were switched to high calcium concentration at various times (from 0 to 48 h), after pulse labelling with [3H]-thymidine. Based on the PLM data, the behaviour of cells known to be in S, G1 and G2 at the time of the migration stimulus were followed. No significant difference in the percentage of labelled suprabasal cells was found for any point of the cell cycle. For cells submitting to stratification, in S phase involucrin staining showed that about 60% of the [3H]-thymidine labelled cells were also involucrin negative. These results indicate that upward migration of keratinocytes in cultured epithelium can be triggered at all points in the cell cycle with equal probability and is not restricted to those cells that already contained involucrin.SCOPUS: ar.jFLWNAinfo:eu-repo/semantics/publishe

Molecular cytogenetic detection of 9q34 breakpoints associated with nail patella syndrome

The nail patella syndrome (NPS1) is an autosomal dominant disorder characterised by dysplasia of the finger nails and skeletal abnormalities. NPS1 has been mapped to 9q34, to a 1 cM interval between D9S315 and the adenylate kinase gene (AK1). We have mapped the breakpoints within the candidate NPS1 region in two unrelated patients with balanced translocations, One patient [46,XY,t(1;9) (q32,1;q34)] was detected during a systematic survey of old cytogenetic files in Denmark and southern Sweden. The other patient [46,XY,t(9;17) (q34,1;q25)] was reported previously D9S315 and AK1 were used to isolate YACs, from which endclones were used to isolate PACs, Two overlapping PAC clones span the 9q34 breakpoints in both patients, suggesting that NPS1 is caused by halopinsufficiency due to truncation or otherwise inactivation of a gene at or in the vicinity of the breakpoints

A novel X–linked gene, DDP, shows mutations in families with deafness (DFN–1), dystonia, mental deficiency and blindness

In 1960, progressive sensorineural deafness (McKu-sick 304700, DFN-1) was shown to be X-linked based on a description of a large Norwegian pedigree1 . More recently, it was shown that this original DFN-1 family represented a new type of recessive neurodegenerative syndrome characterized by postlingual progressive sensorineural deafness as the first presenting symptom in early childhood, followed by progressive dystonia, spasticity, dysphagia, mental deterioration, paranoia and cortical blindness. This new disorder, termed Mohr-Tranebjasrg syndrome (referred to here as DFN-1/MTS) was mapped to the Xq21.3–Xq22 region2. Using positional information from a patient with a 21-kb deletion in chromosome Xq22 and sensorineural deafness along with dystonia, we characterized a novel transcript lying within the deletion as a candidate for this complex syndrome. We now report small deletions in this candidate gene in the original DFN-1/MTS family, and in a family with deafness, dystonia and mental deficiency but not blindness. This gene, named DDP (deaf-ness/dystonia peptide), shows high levels of expression in fetal and adult brain. The DDP protein demonstrates striking similarity to a predicted Schizosaccharomyces pombe protein of no known function. Thus, is it likely that the DDP gene encodes an evolutionarily conserved novel polypeptide necessary for normal human neurological development