Biomedical subjects

A Barabash

Publications and source records attributed to A Barabash.

5 recordsLinked to original sources

PubMed2001

Measurement of the beta beta-decay rate of 100Mo to the first excited 0(+) State of 100Ru.

The double-beta beta beta(2 nu)-decay rate of 100Mo to the first excited 0(+) state of 100Ru has been measured by a gamma-gamma coincidence technique that uses two HPGe detectors to observe the two gamma rays ( E(gamma 1) = 590.76 keV; E(gamma 2) = 539.53 keV) from the 100Ru nucleus as it deexcites to the ground state via the 0(+)-->2(+)-->0(+) sequence. Unlike all previous beta beta-decay experiments, this technique provides data which have a large signal-to-background ratio. After a 440-day measurement of a 1.05-kg isotopically enriched (98.4%) disk of 100Mo, 22 detected coincidence events (with an estimated background of 2.5 events) yield a half-life of [5.9(+1.7)(-1.1)(stat)+/-0.6(syst)] x 10(20) years.

Journal Article↗

PubMed1999

The tau gene A0 allele and progressive supranuclear palsy.

BACKGROUND: Recent studies have shown an association between a polymorphic tandem repeat allele, located in intron 9, of the tau gene and progressive supranuclear palsy (PSP). OBJECTIVE: To investigate this tau polymorphism in individuals with a clinical diagnosis of sporadic or familial PSP as well as in cases confirmed by pathology. METHODS: We analyzed the frequency of tau intronic polymorphism, the presence of linkage in two families with multiple cases of PSP, the splicing of exon 10, and direct sequence of the tau gene. RESULTS: We found that patients with a clinical diagnosis of sporadic or familial PSP and individuals with PSP confirmed by neuropathology have greater prevalence of the A0 allele and A0/A0 genotype than controls. This finding, however, was also true for asymptomatic relatives of individuals with PSP. Linkage analysis in familial PSP excluded the location of the gene in the region 17q21. Furthermore, no significant differences were found in the level of expression of exon 10 in PSP, A0/A0 brain with respect to Alzheimer A3/A3 brain. We found no mutations in the tau gene in individuals with familial PSP. CONCLUSIONS: A mutation in the tau gene was not the primary cause of familial PSP. The role of tau and the tau A0 allele in white PSP patients remains unknown, although it may represent a genetic risk factor for several neurodegenerative disorders.

Aged↗

PubMed1997

Mutation analysis of the BRCA2 gene in breast/ovarian cancer Spanish families: identification of two new mutations.

The recently isolated gene BRCA2 is responsible for about 45% of familial breast cancer and the majority of male breast cancer families. We have screened 12 high risk breast/ovarian Spanish families for mutations in BRCA2, using SSCP followed by direct sequencing. We have found mutations in four of our 12 families (33.3%), including two with male breast cancer. Three of the mutations were frameshift and one was a missense. Two of the mutations have been previously published and two are new mutations.

Adult↗

PubMed1997

[A clinical, cytogenetic and molecular study of 10 patients with the Prader-Willi syndrome].

BACKGROUND: The Prader-Willi syndrome (PWS) is a neurogenetic disorder associated with abnormalities in the chromosomal region 15q11-13 of paternal origin. Most cases (65-85%) have a deletion involving the paternally derived chromosome and the remainder (20-25%) have a maternal uniparental disomy. Some patients have a defect in the imprinting process. We report the results of molecular, cytogenetic and clinical studies on 10 PWS patients. PATIENTS AND METHODS: 18 suspected patients were classified as PWS typical or not typical as they fulfilled or not the clinical criteria for PWS. Cytogenic studies-high resolution chromosome banding analyses (HRGTG) and fluorescence in situ hybridization (FISH) -and molecular chromosome genetic analyses--microsatellite markers and Southern blotting--were carried out from peripheral blood lymphocytes. RESULTS: PWS was confirmed in 10 probands. 8 fulfilled the clinical criteria for PWS and showed cytogenetic and/or molecular abnormalities. In 2 patients without clinical or cytogenetic data, diagnosis was confirmed by molecular methods only. Cytogenetic and molecular findings describe a characteristic clinical picture of PWS. CONCLUSIONS: Cytogenetic techniques (FISH and HRGTG) confirmed PWS diagnosis in 40% of cases, microsatellite studies in 70% of them and Southern blotting (the metilation test) in 100% cases. Southern blotting is the method of choice for rapid diagnostic testing of patients suspected of having PWS.

Adolescent↗

PubMed1991

Reversion of the steroid-induced decrease of serum osteocalcin with sodium fluoride.

Osteopenia observed in corticotherapy is due, among other causes, to a decrease in bone formation as can be shown by a steroid-induced osteocalcin decrease. Although various treatments have been proposed there is no agreement as to which one is the best. Two such treatments, sodium fluoride and vitamin D administration increase osteocalcin levels. We treated a group of 12 patients under corticoid therapy (mean dose 16 mg per day) with 50 mg/day p.o. sodium fluoride, and determined osteocalcin levels before and two weeks after sodium fluoride treatment. Similarly, another group of 9 patients with a similar mean steroid dose was treated with 0.5 micrograms/day of 1 alpha (OH)2D3 in order to assess the effect of this vitamin on osteocalcin and to determine which was the best treatment. Both groups were compared with respective control groups. A significant osteocalcin increase was observed in the control groups (p less than 0.001); similar significance was observed in the sodium fluoride group, whereas a lower significance (p less than 0.01) was observed in the vitamin D group. These results suggest that sodium fluoride could be more effective than vitamin D in the treatment of steroid-induced osteopenia.

Adrenal Cortex Hormones↗