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Biomedical subjects

C Duff

Publications and source records attributed to C Duff.

5 recordsLinked to original sources

Polymorphisms and deduced amino acid substitutions in the coding sequence of the ryanodine receptor (RYR1) gene in individuals with malignant hyperthermia.

Twenty-one polymorphic sequence variants of the RYR1 gene, including 13 restriction fragment length polymorphisms (RFLPs), were identified by sequence analysis of human ryanodine receptor (RYR1) cDNAs from three individuals predisposed to malignant hyperthermia (MH). All RFLPs were detectable in PCR-amplified products, and their segregation was consistent with our initial finding of linkage to MH in the nine families previously informative for one or more intragenic markers (MacLennan et al., 1990, Nature 343:559-561). Four amino acid substitutions were identified in the study: Arg for Gly248, Cys for Arg470, Leu for Pro1785, and Cys for Gly2059. Of 45 families tested, a single family presented the Arg for Gly248 substitution where it segregated with malignant hyperthermia, making it a candidate mutation for predisposition to MH in man. The other three polymorphic substitutions failed to segregate with malignant hyperthermia in those families in which they occurred, implying that they represent polymorphisms with little or no effect on the function of the RYR1 gene.

Amino Acids

[Severe necrotizing fasciitis].

The pathophysiology of necrotizing fasciitis remains unclear in patients with no apparent immunologic disorders. Between 1987 and 1990 we treated six patients with necrotizing fascitis and septic-toxic multiple organ failure, three patients survived. The mean age was 38 years (25-62). In all patients the primary bacteriological examination revealed streptococcus. Between the first symptoms and an adequate therapy were 4 days in surviving patients and 7 days in patients who died. Four patients showed spread of the gangrene into the adjacent tissue: muscles (n = 3), bowel (n = 2), mediastinum (n = 1). Adequate débridement was not possible or not performed in patients with spread into the abdominal cavity or the mediastinum. These patients did not survive. The duration of intensive care treatment in surviving patients were 14 to 78 days. We conclude that survival of patients with severe necrotizing fasciitis is influenced by the delay before adequate treatment, the localisation of the gangrene and intensive care facilities.

Adult

[False aneurysm in a vascular surgery patient population].

40 false aneurysms have been diagnosed at the University Hospital in Zürich during the last three years. These aneurysms are mainly (24) anastomotic aneurysms with synthetic arterial substitutes. 6 false aneurysms were found after arterial catheterization. The majority of these 40 aneurysms (60%) were localized in vicinity of joints. The time interval between the original procedure (anastomosis, arterial catheterization, trauma) and the diagnosis of false aneurysm varies from a few days to 21 years. In seven cases a endarterectomy preceded the development of a false aneurysm. Three therapeutic groups are presented.

Adult

Karyotyping.

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Animals

Chromosome stability in CHO cells.

The established cell line derived many years ago from Chinese hamster ovary (CHO cells) has been studied for the extent of chromosomal variation. Because this cell line is used extensively for genetic studies, the contribution of chromosome variability to genetic variability has also been examined. The quasidiploid CHO cells were found to have a banded karyotype somewhat altered from that of the Chinese hamster from which the line was derived. However, most of the genome could be accounted for among the rearranged marker chromosomes. In addition, the CHO line was found to have a relatively stable karyotype, the same basic karyotype being found in a majority of the uncloned cells, as well as in most cells of several but not all independent clones. Many, but not all, mutant cell lines derived from CHO also showed the same basic karyotype. Quasitetraploid cells, derived either spontaneously or by Sendai-virus-induced fusion, showed considerably more variation resulting in loss or gain of whole chromosomes, rearrangement of chromosomes, and appearance of new "marker" chromosomes.

Cell Line