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Biomedical subjects

P Fournier

Publications and source records attributed to P Fournier.

At least 199 records · Page 11Linked to original sources
PubMedDate not supplied

Chromosomal polymorphism of the yeast Yarrowia lipolytica and related species: electrophoretic karyotyping and hybridization with cloned genes.

Significant differences in electrophoretic karyotyping patterns were found among 27 strains of Y. lipolytica. Twenty-one of these strains were classified into four groups of similar karyotypes while six strains showed unique karyotypes. Chromosomal DNAs of different strains were hybridized with cloned genes of Y. lipolytica (URA3, LEU2, ARS18 and ARS68), which revealed four different bands in most strains. We conclude that the haploid chromosome number of Y. lipolytica is at least four, and possibly five or six. Electrophoretic karyotyping and hybridization with cloned genes of Y. lipolytica provided evidence of a large divergence between Y. lipolytica and related species of Saccharomycopsis, Endomycopsella and Endomyces.

Blotting, Southern↗
PubMedDate not supplied

Mitochondrial mutation associated with nonsyndromic deafness.

PURPOSE: The first mutation associated with nonsyndromic deafness has recently been identified in pedigrees with susceptibility to aminoglycoside ototoxicity and in a large Arab-Israeli pedigree. The mutation is maternally transmitted, and is a nucleotide substitution in the mitochondrial 12S ribosomal RNA gene. A different sequence change, in the mitochondrial tRNA(Ser)(UCN)/COI gene, has been proposed as a candidate mutation in a Scottish nonsyndromic deafness pedigree. We have now identified a family in New Zealand with maternally inherited nonsyndromic sensorineural deafness, and the purpose of the current study is to identify the molecular basis of deafness in this family. MATERIALS AND METHODS: A family tree was established by history and chart review, and audiological and clinical data were obtained. Blood was sampled from 10 family members, and lymphoblastoid cell lines were established for 4 of them. The DNA of these individuals was extracted, and the mitochondrial genome was analyzed by Southern blot analysis for gross rearrangements. Subsequently, the entire coding sequence of the mitochondrial genome was sequenced, compared to the normal sequence, and all sequence variations were analyzed by allele-specific oligonucleotide hybridization or restriction enzyme analysis. RESULTS: Several candidate mutations were identified, one of them being the nucleotide 7445 A-->G mutation in the mitochondrial tRNAser(UCN)/COI gene. This mutation was heteroplasmic and identical to the one previously identified in the Scottish pedigree. CONCLUSIONS: The finding of the same heteroplasmic mutation in two independent pedigrees with the same phenotype and transmission pattern, establishes this sequence change as the most likely determinant of the deafness phenotype in these families. This implies that nonsyndromic deafness can be caused by mutations in generalized cell processes, such as oxidative phosphorylation, rather than in hearing specific molecules.

Adolescent↗
PubMedDate not supplied

[Phosphocalcium metabolism in the elderly. Study of 101 subjects living in an institution].

Calcium and phosphorus metabolism was studied in 101 institutionalized subjects over 70 years of age (mean: 82.5 years). The study was performed in serum and urine; it included parathyroid hormone and calcidiol (250HD3) assays and radiological examination of bones with determination of Meunier's index and metacarpal cortical index. Calcidiol concentrations did not vary with age but were higher in people who left the institution and in men. In contrast, there was a significant age-group related increase of parathyroid hormone concentrations. This increase was accompanied by an increase of parathyroid hormone activity, as shown by a parallel fall in phosphorus reabsorption rate. These findings are in agreement with current pathogenetic theories on senile osteoporosis. Invalid subjects had higher urinary calcium and serum parathyroid hormone levels and a lower cortical index. Paradoxically, there was less vertebral collapse as evaluated by Meunier's index, which may suggest that very old patients develop progressive cortical bone hyperresorption entirely independent of sequelae from their former trabecular osteoporosis.

Aged↗
PubMedDate not supplied

[comparison of the effects on phosphocalcic metabolism and bone of 3 protocols of vitamin D administration in the elderly].

According to recent studies, vitamin D deficiency may contribute to the osteoporosis observed in elderly subjects, with reduced intestinal calcium absorption and secondary hyperparathyroidism. Vitamin D deficiency is often present in elderly people, due to inadequate diet and confinement at home. The administration of either oral vitamin D in doses of 4,000 IU per day, or six-monthly intramuscular injections of ergocalciferol 600,000 IU, combined with a daily intake of at least 1 g of calcium brings back to normal both 25 OH D concentrations and parathyroid hormone levels. When pursued for one year, these treatments also maintain the formation of cortical bone, as shown by the metacarpal index. As for the concentration of 25 OH D, it seems that 60 to 75 nmol/l are necessary to restore calcium homeostasis. The dietary habits of elderly people are such that a supplement of medicinal calcium is required. Finally, we regard the parenteral form of ergocalciferol as being preferable to the oral form at that age for better compliance with treatment.

Administration, Oral↗
PubMedDate not supplied

Anterior neopharyngeal pseudodiverticulum. A possible cause of dysphagia in laryngectomized patients.

Anterior neopharyngeal pseudodiverticula are out-pouchings of the neopharyngeal lumen in laryngectomized patients which can cause postoperative dysphagia. In this study 20 laryngectomized patients were examined endoscopically and with barium swallow to determine the frequency of pseudodiverticulum formation, the correlation with clinical symptoms, and to evaluate the best modality for diagnosis. In 12 patients an anterior neopharyngeal pseudodiverticulum was present. Of these patients eight complained of dysphagia. The barium swallow showed more clearly the pseudodiverticula than laryngoscopy and gave additional information on functional implications. All symptomatic patients were successfully operated on with endoscopic laser therapy.

Adult↗
PubMedDate not supplied

Natural instability of Agrobacterium vitis Ti plasmid due to unusual duplication of a 2.3-kb DNA fragment.

The octopine/cucumopine (o/c) Ti plasmids of Agrobacterium vitis carry two T regions, TA and TB. The TA region resembles the octopine TL region. The TB region contains the auxin synthesis genes TB-iaaM and TB-iaaH and the cucumopine synthesis gene cus. Within the group of o/c isolates, strains 2608 and 2641 are closely related. However, 2641 lacks the TB region. The restriction maps of pTi2608 and pTi2641 were established and showed that the TB deletion resulted from intramolecular recombination between two directly repeated sequences separated by 66 kb in pTi2608. The 2,294-bp repeated sequence lacks inverted repeats and does not duplicate its target site, indicating that it is not a classical bacterial insertion sequence (IS element). It was therefore called an RSAv element (repeated sequence of A. vitis). The RSAv element carries two open reading frames: ORF234 is homologous to the traR gene of the A. tumefaciens nopaline Ti plasmid pTiC58; ORF488 is homologous to the sucrose phosphorylase gene of Leuconostoc mesenteroides and the glucosyl transferase A gene of Streptococcus mutans. The RSAv repeat starts precisely at the start codon of ORF488 and ends two base pairs 3' of the stop codon of ORF234. The structural organization of the RSAv element suggests that the amplification event did not result from a random amplification process. A study of the distribution of the two RSAv copies (RSAv-1 and RSAv-2) in pTi2608 and other o/c isolates indicates that the ancestor o/c Ti plasmid contained only RSAv-1 and that this sequence was duplicated at one point during the divergent evolution of the o/c Ti plasmids.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗