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J F Andersen

Publications and source records attributed to J F Andersen.

34 records · Page 2Linked to original sources
PubMed1994

Report of the European DNA profiling group (EDNAP)--towards standardisation of short tandem repeat (STR) loci.

This paper describes a collaborative exercise intended to demonstrate whether uniformity of DNA profiling results could be achieved between European laboratories using short tandem repeat (STR) loci. Two different STRs were chosen--HUMTH01 and the AT-rich HUMACTBP2 (SE33). The former locus has only five common alleles, whereas the latter is complex and has at least 30 alleles. Laboratories were asked to test seven blood stains and to report the results to the coordinating laboratory. The exercise demonstrated that the simple STR systems such as HUMTH01 are more amenable to adoption as standard loci than complex AT-rich systems.

Alleles↗
PubMed1994

Generation of minisatellite variant repeat codes on an automated DNA sequencer using fluorescent dye-labeled primers.

We demonstrate the potential to generate unambiguous minisatellite variant repeat PCR profiles on an automated DNA sequencer using fluorescent dye-labeled primers. The products of a 24-cycle PCR amplification using 100 ng of template DNA were analyzed by conventional blot hybridization and also on an Applied Biosystems 373A DNA Sequencer. The results from the sequencer were clear to the 20th repeat when using a primer labeled with 6-FAM, whereas conventional analysis allowed codes to be defined to in excess of the 60th repeat. Use of a modified Tag primer sequence, which eliminates the potential for self-annealing, did not improve the clarity of the results under the PCR cycling conditions used.

Autoanalysis↗
PubMed1993

Substrate specificity of 6-deoxyerythronolide B hydroxylase, a bacterial cytochrome P450 of erythromycin A biosynthesis.

The 6-deoxyerythronolide B hydroxylase (EryF) is a soluble cytochrome P450 responsible for the stereospecific C-6 hydroxylation of the erythromycin precursor, 6-deoxyerythronolide B. Using the expression of the eryF gene in Escherichia coli [Andersen, J. F., & Hutchinson, C. R. (1992) J. Bacteriol. 174, 725-735] as the enzyme source, we examined the catalytic activity of the EryF protein toward several macrolide substrates related to 6-deoxyerythronolide B. The results of these studies were compared with measurements of the apparent dissociation constants for various substrates and with information from molecular modeling studies of the substrates and the enzyme-substrate complex. Only minor changes in the structure of 6-deoxyerythronolide B resulted in substrates with catalytic rates less than 1% of those seen with the natural substrate. Although the 9S epimer of 9-deoxo-9-hydroxy-6-deoxyerythronolide B was hydroxylated at a rate approximately equal to the natural substrate, the 9R epimer was hydroxylated at a 2-fold lower rate. Examination of molecular models revealed that the position of the 9-hydroxyl oxygen in the 9S epimer resembles that of the 9-oxo oxygen in the natural substrate more closely than in the 9R epimer. 8,8a-Deoxyoleandolide, which is identical to 6-deoxyerythronolide B except for the presence of a C-13 methyl group, and its (9S)-9-deoxo-9-hydroxy derivative were C-6 hydroxylated at a 4-fold lower rate than the natural substrate, and the 9-oxo form showed a substantially larger apparent dissociation constant.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1992

Characterization of Saccharopolyspora erythraea cytochrome P-450 genes and enzymes, including 6-deoxyerythronolide B hydroxylase.

Previous studies of erythromycin biosynthesis have indicated that a cytochrome P-450 monooxygenase system is responsible for hydroxylation of 6-deoxyerythronolide B to erythronolide B as part of erythromycin biosynthesis in Saccharopolyspora erythraea (A. Shafiee and C. R. Hutchinson, Biochemistry 26:6204-6210 1987). The enzyme was previously purified to apparent homogeneity and found to have a catalytic turnover number of approximately 10(-3) min-1. More recently, disruption of a P-450-encoding sequence (eryF) in the region of ermE, the erythromycin resistance gene of S. erythraea, produced a 6-deoxyerythronolide B hydroxylation-deficient mutant (J. M. Weber, J. O. Leung, S. J. Swanson, K. B. Idler, and J. B. McAlpine, Science 252:114-116, 1991). In this study we purified the catalytically active cytochrome P-450 fraction from S. erythraea and found by using sodium dodecyl sulfate-polyacrylamide gel electrophoresis that it consists of a major and a minor P-450 species. The gene encoding the major species (orf405) was cloned from genomic DNA and found to be distinct from eryF. Both the orf405 and eryF genes were expressed in Escherichia coli, and the properties of the proteins were compared. Heterologously expressed EryF and Orf405 both reacted with antisera prepared against the 6-deoxyerythronolide B hydroxylase described by Shafiee and Hutchinson (1987), and the EryF polypeptide comigrated with the minor P-450 species from S. erythraea on sodium dodecyl sulfate-polyacrylamide gel electrophoresis gels. In comparisons of enzymatic activity, EryF hydroxylated a substrate with a turnover number of 53 min-1, whereas Orf405 showed no detectable activity with a 6-deoxyerythronolide B analog. Both enzymes showed weak activity in the O-dealkylation of 7-ethoxycoumarin. We conclude that the previously isolated 6-deoxyerythronolide B hydroxylase was a mixture of two P-450 enzymes and that only the minor form shows 6-deoxyerythronolide B hydroxylase activity.

Amino Acid Sequence↗
PubMed1985

The value of transvascular embolization in the treatment of renal carcinoma.

In a consecutive series of 62 patients with renal carcinoma transvascular embolization has been evaluated in regard to its limitations, complications, influence on the surgical procedure and success of treatment. Of 47 planned embolizations 36 could be accomplished. Total embolization was achieved in 29 of the 36 cases (81 per cent). One case was complicated due to displacement of the embolization material to the femoral artery. The subjective impression of the surgeon was that embolization facilitated nephrectomy, although this could not be proved by objective measurement of the duration of operation and perioperative blood loss. Survival after embolization and nephrectomy was no better than after nephrectomy alone.

Adult↗
PubMed1981

Large bowel volvulus in children. Review of a case material and the literature.

Four pediatric patients with volvulus of the right colon, and three others with twisting of the sigmoid colon are reported. The clinical manifestations, mainly pain, were vague. Radiological plain film findings were occasionally characteristic, but were in the majority of cases equivocal. An active radiological approach including a supplementary barium enema in any patient with inconclusive plain abdominal roentgenograms will, in addition to other unexpected diagnoses, reveal rare cases of large bowel volvulus. Elective surgical procedures, carried out on viable bowel do not necessarily provide advantages over a non-operative approach. In addition spontaneous reduction of the volvulus may result in permanent cure.

Barium Sulfate↗
PubMed1981

Segmental vascular occlusion of the colon. A tentative diagnosis in two pediatric cases.

Segmental vascular occlusion of the colon is a rare, quite commonly reversible condition, so far recorded only in adults. The present report deals with two pediatric patients displaying clinical and radiological findings consistent with this entity. A benign course of disease with rapidly subsiding manifestation support our interpretation. The etiology remains obscure.

Child↗
PubMed1979

The value of plain radiographs prior to oral cholecystography.

The diagnostic significance of a routine preliminary plain radiograph of the right upper abdominal quadrant prior to oral cholecystography was evaluated retrospectively. The plain radiograph was decisive in the diagnosis in only one case out of 1,022 consecutive cholecystographic examinations (0.1%) (95% confidence limits: 0.00-0.55%). The sensitivity of oral cholecystography, now approximately 90%, would drop by only 0.43% (95% confidence limits: 0.01-2.14%) if the routine plain radiograph were omitted.

Cholecystography↗