Exploring mechanisms of sex differences in longevity: lifetime ovary exposure and exceptional longevity in dogs.

To move closer to understanding the mechanistic underpinnings of sex differences in human longevity, we studied pet dogs to determine whether lifetime duration of ovary exposure was associated with exceptional longevity. This hypothesis was tested by collecting and analyzing lifetime medical histories, age at death, and cause of death for a cohort of canine 'centenarians'--exceptionally long-lived Rottweiler dogs that lived more than 30% longer than average life expectancy for the breed. Sex and lifetime ovary exposure in the oldest-old Rottweilers (age at death, > or = 13 years) were compared to a cohort of Rottweilers that had usual longevity (age at death, 8.

Specific negative effects resulting from elevated levels of the recombinational repair protein Rad54p in Saccharomyces cerevisiae.

RAD54 is an important gene in the RAD52 group that controls recombinational repair of DNA damage in Saccharomyces cerevisiae. Rad54p is a DNA-dependent ATPase and shares seven conserved sequence motifs with proteins of the Swi2p/Snf2p family. Genetic analysis of mutations in motif IA, the putative ATP-binding fold of Rad54p, demonstrated the functional importance of this motif.

Orthotopic liver transplantation with preservation of portocaval flow compared with venovenous bypass.

Conventional liver transplantation requires cross-clamping of the hepatic pedicle and inferior vena cava, leading to severe hemodynamic and metabolic disturbances, usually attenuated by the use of venovenous bypass. A more recent surgical technique, piggyback with temporary portocaval shunting, preserves both caval and portal blood flows. The aim of this study was to compare the two methods prospectively.

Recombinational repair in yeast: functional interactions between Rad51 and Rad54 proteins.

Rad51p is a eukaryotic homolog of RecA, the central homologous pairing and strand exchange protein in Escherichia coli. Rad54p belongs to the Swi2p/Snf2p family of DNA-stimulated ATPases. Both proteins are also important members of the RAD52 group which controls recombinational DNA damage repair of double-strand breaks and other DNA lesions in Saccharomyces cerevisiae.

Homologous recombination in the fission yeast Schizosaccharomyces pombe: different requirements for the rhp51+, rhp54+ and rad22+ genes.

The Schizosaccharomyces pombe rhp51+, rad22+ and rhp54+ genes are homologous to RAD51, RAD52 and RAD54 respectively, which are indispensable in the recombinational repair of double-strand breaks (DSBs) in Saccharomyces cerevisiae. The rhp51Delta and rhp54Delta strains are extremely sensitive to ionizing radiation; the rad22Delta mutant turned out to be much less sensitive. Homologous recombination in these mutants was studied by targeted integration at the leu1-32 locus.

Human and mouse homologs of the Saccharomyces cerevisiae RAD54 DNA repair gene: evidence for functional conservation.

Background: Homologous recombination is of eminent importance both in germ cells, to generate genetic diversity during meiosis, and in somatic cells, to safeguard DNA from genotoxic damage. The genetically well-defined RAD52 pathway is required for these processes in the yeast Saccharomyces cerevisiae. Genes similar to those in the RAD52 group have been identified in mammals.

The yeast HRS1 gene encodes a polyglutamine-rich nuclear protein required for spontaneous and hpr1-induced deletions between direct repeats.

The hrs1-1 mutation was isolated as an extragenic suppressor of the hyperrecombination phenotype of hpr1 delta cells. We have cloned, sequenced and deleted from the genome the HRS1 gene. The DNA sequence of the HRS1 gene reveals that it is identical to PGD1, a gene with no reported function, and that the Hrs1p protein contains polyglutamine stretches typically found in transcription factors.

[An unusual failure of the 900 C Siemens Servo ventilator].

Lung overinflation was observed in a patient ventilated by a Siemens Servo Ventilator 900 C. The expiratory valves failure to open was related to a transducer disconnection in the expiratory limb. This transducer controls opening of the expiratory valve and when disconnected expiratory valve remains closed.