Biomedical subjects
B Frost
Publications and source records attributed to B Frost.
Nurses' perceptions of powerlessness in influencing ethical decisions.
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Effect of enzymatic methylation of cytochrome c on its function and synthesis.
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Effect of enzymatic methylation of apocytochrome c on holocytochrome c formation and proteolysis.
1. Methylation of the lysine at residue 72 of yeast apocytochrome c increases its import into mitochondria. 2. Using methylated and unmethylated apocytochrome c as substrate and intact yeast mitochondria and a solubilized mitochondrial fraction as a source of cytochrome c heme lyase, the results show that the methylation state of the apoprotein has no significant effect on its conversion to holoprotein. 3. The above result suggests that the import mechanism is separate from the heme-attaching activity. 4. Unmethylated apocytochrome c was less resistant to a yeast homogenate fraction that methylated apocytochrome c, suggesting that methylation of apocytochrome c alters the conformation of the whole protein.
Cytochrome c methylation.
In this review, protein methylation is outlined in general terms, highlighting the major amino acids that are methylated and some of the proteins in which they are found. The majority of the review examines the methylation of cytochrome c at Lys-77 of lower eukaryotes as a possible model for methylation studies. Early work involving the purification and characterization of the methyltransferase responsible for this methylation indicated cytochrome c was methylated posttranslationally, yet prior to import into the mitochondria. Methylation in vitro occurred only at the in vivo methylation site and only on cytochrome c. Later studies using in vitro translated apocytochrome c revealed that methylated, as compared with unmethylated, apocytochrome c was imported preferentially into yeast, but not rat liver, mitochondria. Efforts to discover the reasons for this preference have shown that methylation of apocytochrome c dramatically lowers its isoelectric point (against a predicted increase) and decrease its Stokes radius. A possible mechanism for these differences involving the disruption of hydrogen bonds is presented here with space-filling models. Finally, the in vivo significance of this modification is also discussed.
Multiple diverticula of the ureter.
Multiple ureteral diverticula are rare and not previously reported in Scandinavian literature. Various etiologic factors have been considered. In our opinion, it is a congenital abnormality, not in itself demanding specific therapy. Diverticulosis ureteris is not seen at ordinary excretory pyelography, and only occasionally at a high volume excretory pyelography with compression. They are best visualized by retrograde pyelography, and the incidence may, therefore, be higher than hitherto anticipated.
Hb G Norfolk associated with malignant myelosclerosis.
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[Psychiatric activities in the Luleå nursing district].
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Complications of peritoneal dialysis.
Peritoneal dialysis is an easily available therapeutic procedure. The complications noted in 490 dialyses over a six-year period in a university hospital have been reviewed. Seventeen major and 624 minor complications occurred. Only four deaths could be attributed to the procedure itself. Peritoneal dialysis is an effective procedure but one with a significant incidence of complications, though few of these are associated with mortality or morbidity for the patient. Various safeguards against these are discussed.
Precolumn phenylisothiocyanate derivatization and liquid chromatography of amino acids in food.
A precolumn phenylisothiocyanate derivatization method is described for the determination of amino acids in protein hydrolysates from a wide variety of complex food matrixes, with and without performic acid oxidation pretreatment. Analysis of samples that were not pretreated with performic acid was necessary since this pretreatment destroyed an average of 25% of the histidine and 87% of the tyrosine present in the food samples. This method is rapid and reproducible; coefficients of variation between duplicate analyses of the same food item were less than 5% for a majority of the amino acids. Occasionally, variation between duplicate analyses for histidine and tyrosine was greater than 10%. Recoveries of amino acids added to samples were in the 100% range.