Gene promoter hypermethylation is found in sentinel lymph nodes of breast cancer patients, in samples identified as positive by one-step nucleic acid amplification of cytokeratin 19 mRNA.

We analysed the promoter methylation status of five genes, involved in adhesion (EPB41L3, TSLC-1), apoptosis (RASSF1, RASSF2) or angiogenesis (TSP-1), in intraoperative sentinel lymph node (SLN) biopsy samples from patients with breast cancer, that had been processed by the one-step nucleic acid amplification (OSNA) technique. SLN resection is performed to estimate the risk of tumour cells in the clinically negative axilla, to avoid unnecessary axillary lymph node dissection. OSNA is currently one of the eligible molecular methods for detecting tumour cells in SLNs. It is based on the quantitative evaluation of cytokeratin 19 mRNA which allows distinguishing between macrometastasis, micrometastasis and isolated tumour cells, on the basis of the quantity of tumour cells present. There have been no prior studies on the question whether or not samples processed by OSNA can be used for further molecular studies, including epigenetic abnormalities which are some of the most important molecular alterations in breast cancer. Genomic DNA was extracted from samples obtained from 50 patients diagnosed with primary breast cancer. The content of tumour cells in SLNs was evaluated by OSNA, and the promoter methylation status of the selected genes was analysed by methylation-specific PCR. All were found to be hypermethylated to a variable degree, and RASSF1 hypermethylation was significantly associated with macrometastasis, micrometastasis and isolated tumour cells (p = 0.002). We show that samples used for OSNA are suitable for molecular studies, including gene promoter methylation. These samples provide a new source of material for the identification of additional biomarkers.

[The effect on the use of hospital resources in a geriatric domiciliary care program among the elderly patients with advanced cardiorespiratory diseases]. / Efecto sobre el consumo de recursos hospitalarios de un programa de atención geriátrica domiciliaria en personas ancianas con patología cardiorrespiratoria muy evolucionada.

BACKGROUND: One of the objectives of the geriatric home care teams is that of the follow-up of elderly patients having a high risk of hospital readmission. Although they have been operating in our country for years, no data shows the impact on the use of hospital resources in accordance with this follow-up. The objective of this study is that of analyzing the effect which the monitoring, by geriatric home care unit, involves on patients having very advanced chronic cardiorespiratory disease. METHODS: The patients with chronic cardiorespiratory disease followed up by the unit during the January 1995-January 1999 period were included, excluding those on follow-up for less than 3 months. A comparison is drawn among the number of hospital emergency room visits, hospital admissions and days of hospitalization for the year prior to the care provided by the unit and throughout the follow-up time thereof are compared. RESULTS: Eighty-one (81) patients, mean age 80.57 years (DE 7.39) and a median length of care per unit of nine (9) months (5-13.5), were included in the study. The uses per patient and month of follow-up decreased by 0.07 Emergency Room visits (0.02-0.11) (p = 0.04), 0.10 hospital admissions (0.07-0.14) (p < 0.001) and 2.01 days of hospitalization (1.87-2.15) (p < 0.001). CONCLUSIONS: A specialized geriatric home care unit reduces the use of hospital resources on elderly people diagnosed as severe chronic cardiorespiratory disease.

Mutagenesis of SNM1, which encodes a protein component of the yeast RNase MRP, reveals a role for this ribonucleoprotein endoribonuclease in plasmid segregation.

RNase MRP is a ribonucleoprotein endoribonuclease that has been shown to have roles in both mitochondrial DNA replication and nuclear 5.8S rRNA processing. SNM1 encodes an essential 22.5-kDa protein that is a component of yeast RNase MRP. It is an RNA binding protein that binds the MRP RNA specifically. This 198-amino-acid protein can be divided into three structural regions: a potential leucine zipper near the amino terminus, a binuclear zinc cluster in the middle region, and a serine- and lysine-rich region near the carboxy terminus. We have performed PCR mutagenesis of the SNM1 gene to produce 17 mutants that have a conditional phenotype for growth at different temperatures. Yeast strains carrying any of these mutations as the only copy of snm1 display an rRNA processing defect identical to that in MRP RNA mutants. We have characterized these mutant proteins for RNase MRP function by examining 5.8S rRNA processing, MRP RNA binding in vivo, and the stability of the RNase MRP RNA. The results indicate two separate functional domains of the protein, one responsible for binding the MRP RNA and a second that promotes substrate cleavage. The Snm1 protein appears not to be required for the stability of the MRP RNA, but very low levels of the protein are required for processing of the 5.8S rRNA. Surprisingly, a large number of conditional mutations that resulted from nonsense and frameshift mutations throughout the coding regions were identified. The most severe of these was a frameshift at amino acid 7. These mutations were found to be undergoing translational suppression, resulting in a small amount of full-length Snm1 protein. This small amount of Snm1 protein was sufficient to maintain enough RNase MRP activity to support viability. Translational suppression was accomplished in two ways. First, CEN plasmid missegregation leads to plasmid amplification, which in turn leads to SNM1 mRNA overexpression. Translational suppression of a small amount of the superabundant SNM1 mRNA results in sufficient Snm1 protein to support viability. CEN plasmid missegregation is believed to be the result of a prolonged telophase arrest that has been recently identified in RNase MRP mutants. Either the SNM1 gene is inherently susceptible to translational suppression or extremely small amounts of Snm1 protein are sufficient to maintain essential levels of MRP activity.