Biomedical subjects

A Haid

Publications and source records attributed to A Haid.

41 records · Page 3Linked to original sources

PubMed1981

Expression of the "split gene" COB in yeast mtDNA. Translation of intervening sequences in mutant strains.

This study deals with the effects that mutations in the COB region of yeast mtDNA have on the expression of mitochondrially made polypeptides. Based on the detection of two series of polypeptide chain-terminating mutations, we conclude that two proteins are specified by this region, apocytochrome b (Mr = 30,000) and a polypeptide of Mr = 42,000. One series of mutations generates new polypeptides ranging in size from 8,000 to 29,000 daltons; all of them are precipitated by serum direct against apocytochrome b. These mutations are located in five distinct segments of the COB region, the sequences alpha to epsilon coding for apocytochrome b. The second series of mutations, generating new polypeptides ranging in size from 17,000 to 41,000 daltons, is located within the first intervening sequence (alpha/beta) of the split gene for apocytochrome b. These mutations cause premature chain termination in the COOH-terminal part of a 42,000-dalton polypeptide. Its NH2-terminal part is likely to be specified by sequence alpha and thus to be homologous to that of apocytochrome b. We conclude that the 42,000-dalton polypeptide is translated on a processing intermediate of th COB transcript by reading through sequence alpha into sequence alpha/beta. We discuss the hypothesis that this polypeptide has a function in the expression of the COB region, possibly at the level of transcript processing.

DNA, Mitochondrial↗

PubMed1980

Mutations affecting RNA splicing and the interaction of gene expression of the yeast mitochondrial loci cob and oxi-3.

In Saccharomyces cerevisiae strains KL14-4A and 777-3A, four intervening sequences of 1900 (l alpha beta), 1400 (l beta gamma), 1300 (l gamma delta) and 650 bp (l delta epsilon) separate the five coding sequences (alpha-epsilon) of the structural gene (cob) for cytochrome b. Its major transcript is an 18S RNA (2200 nucleotides) which is likely to be the functional mRNA. The lengths of a series of larger transcripts and their hybridization with probes specific for different intervening sequences are consistent with their being intermediates in a splicing process which generates 18S RNA from a giant primary transcript (greater than or equal to 7.5 kb) covering the whole cob region. There is no absolute order of splicing. The intervening sequence l alpha beta is excised in two stages. The first generates a stable 10S RNA, coded for by sequences immediately downstream of the 18S RNA coding segment alpha. The function of this RNA is unknown. Its excision is an early step in processing, whereas excision of the remainder of l alpha beta is a late event. We have studied four cytochrome b-deficient mutants. These map in intervening sequences and are splicing-defective. They accumulate 22S-28S RNAs which contain one or more intervening sequences. The l alpha beta mutants synthesize long, novel polypeptides, antigenically related to cytochrome b, possibly as a result of read-through into the intervening sequences. Several cob mutants also display alterations in their transcripts of oxi-3, the locus which codes for cytochrome c oxidase subunit I. This indicates that interactions between cob and oxi-3 exist at the level of RNA processing.

Cytochromes↗

PubMed1979

The mitochondrial COB region in yeast codes for apocytochrome b and is mosaic.

Mitochondrial mutants of Saccharomyces cerevisiae defective in cytochrome b were analyzed genetically and biochemically in order to elucidate the role of the mitochondrial genetic system in the biosynthesis of this cytochrome. The mutants mapped between OLI1 and OLI2 on mitochondrial DNA in a region called COB. A fine structure map of the COB region was constructed by rho- deletion mapping and recombination analysis. The combined genetic and biochemical data indicate that the COB region is mosaic and contains at least five distinct clusters of mutants, A-E, with A being closest to OLI2 and E being closest to OLI1. Clusters A, C and E are probably coding regions for apocytochrome b, whereas clusters B and D seem to be involved in as yet unknown functions. These conclusions rest on the following evidence. 1. Most mutants in clusters A, C and E have specifically lost cytochrome b. Many of them accumulate smaller mitochondrial translation products; some of these were identified as fragments of apocytochrome b by proteolytic fingerprinting. The molecular weight of these fragments depends on the map position of the mutant, increasing in the direction OLI2 leads to OLI1. The mutant closest to OLI1 accumulates an apocytochrome b which is slightly larger than that of wild type. 2. A mutant in cluster C exhibits a spectral absorption band of cytochrome b that is shifted 1.5 nm to the red. 3. Mutants in clusters B and D are pleiotropic. A majority of them are conditional and lack the absorption bands of both cytochrome b and cytochrome aa3; these mutants also fail to accumulate apocytochrome b and subunit I of cytochrome c oxidase and instead form a large number of abnormal translation products whose nature is unknown. 4. Zygotic complementation tests reveal at least two complementation groups: The first group includes all mutants in cluster B and the second group includes mutants in clusters (A + C + D + E).

Apoproteins↗

PubMedDate not supplied

Male breast cancer: Austrian experience.

Data were collected on 169 men treated for breast cancer at 36 surgical departments in Austria between 1970 and 1991. We report here several of their clinical features and assess the importance of established prognostic factors. After a median observation period of 51 months 60 patients (35%) suffered a recurrence. The estimated 5-year recurrence-free survival for the entire group was 55%, and the estimated 5-year overall survival was 62%. Although stage-adjusted data are comparable to those for female breast cancer, the outcome in this series may be attributed to a relatively high frequency of advanced tumor stages. Tumor size (recurrence-free survival p = 0.00001; overall survival p = 0.03) and axillary lymph node status (recurrence-free survival p = 0.0001; overall survival p = 0.0001) proved to have a prognostic impact. Using a multivariate analysis, axillary lymph node status (recurrence-free survival p = 0.001; overall survival p = 0.01) still had prognostic influence. The various procedures used had no effect on local recurrence.

Adult↗

PubMedDate not supplied

[Comparative evaluation of four methods of an endotracheal tube holder. Preliminary results].

OBJECTIVE: To compare four different types of endotracheal tube holders. PATIENTS: Patients admitted to Intensive Care Unit in Thertiary Hospital with 800 patients admitted/year. The minimum sample was 188 to obtain statistically significant differences. During the first 6 months, 68 consecutive patients non selected were randomly assigned to one of four types of tube holders. PARAMETERS: Each 8 hours were evaluated the presence of lesions in skin or mucose membrane, colocation facility and patients commodity. Also security and cost analysis parameters were included. STATISTIC ANALYSIS: SPSS statistical package were used, Kaplan-Meier curve, Kruskal-Wallis test; and making statistical contrasts between the different types of tube holders. We considered significant a p < 0.05. RESULTS AND CONCLUSIONS: The obtained results till this moment showed significant differences in time free of lesions, between Haid holder and the rest of tube holders. Likewise, in the subjective parameters for the nurse and patient evaluations the Haid holder obtained a superior mind in facility of colocation and commodity of patients, consecutive gauze bandage.

Adhesives↗