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Biomedical subjects

K B Petersen

Publications and source records attributed to K B Petersen.

17 recordsLinked to original sources
PubMed1991

Application of fluorescence in situ hybridization techniques in clinical genetics: use of two alphoid repeat probes detecting the centromeres of chromosomes 13 and 21 or chromosomes 14 and 22, respectively.

Two cloned DNA fragments, one derived from an alpha satellite subfamily common to chromosomes 13 and 21, and the other derived from a similar subfamily common to chromosomes 14 and 22, have been used as biotinylated probes in in situ hybridization studies. Under high stringency conditions, chromosome specific centromeric labelling can be obtained. The applications of this technique in clinical situations are illustrated on metaphases from a fetus with trisomy 21, a fetus with trisomy 13, and a child with clinical features of cat-eye syndrome.

Centromere↗
PubMed1989

Detection of point mutations in amplified single copy genes by biotin-labelled oligonucleotides: diagnosis of variants of alpha-1-antitrypsin.

Specific analysis for point mutations in genomic DNA has until recently been a difficult and time-consuming task, using large amounts of unstable, hazardous and expensive 32P. By enzymatically amplifying the mutation-bearing sequence of the DNA the sensitivity of the analysis is increased several 100-fold, making the detection possible with stable, non-radioactive and inexpensive biotinylated oligonucleotides. We have applied this method (polymerase chain reaction (PCR] to the detection of the Z-mutation in the alpha-1-antitrypsin gene. After amplification, dot-blots of amplified DNA were subjected to hybridization with allele specific biotinylated oligonucleotide probes and washed at temperatures giving allele specificity. The bound biotin was visualized with avidin conjugated alkaline phosphatase using 5-bromo-4-chloro-3-indolylphosphate and nitro blue tetrazolium as colour reagents. The detection can be performed on less than 1 microgram genomic DNA, and is therefore applicable on small amounts of blood, fibroblasts and chorionic villus biopsies.

Base Sequence↗
PubMed1989

Oligonucleotide-priming methods for the chromosome-specific labelling of alpha satellite DNA in situ.

It is demonstrated that either general staining of the centromeric regions of all primate chromosomes, or selective staining of the centromeric region of specific chromosomes, may be obtained in preparations of metaphase chromosomes by probing specifically for different regions within the alpha satellite DNA monomer. In order to exploit observed patterns of sequence variation within the monomer for this purpose, we have developed two new DNA analysis methods. In PRimed IN Situ labelling (PRINS), synthetic oligonucleotides derived from subsections of the monomer are hybridized to the chromosomes. The oligonucleotides then serve as primers for the in situ incorporation of biotin-labelled nucleotides catalysed by Klenow polymerase. Incorporated biotin is visualized with fluorescein isothiocyanate-labelled avidin (FITC-avidin). In Primed Amplification Labelling (PAL), biotin-labelled hybridization probes are produced in a polymerase chain reaction (PCR, Saiki et al. 1985), in which two synthetic oligonucleotide primers anneal within the same monomer. With the right choice of primers libraries of labelled probes derived from most monomers present as templates are produced. If DNA from a specific chromosome is used as template, then the resulting probe mixture gives stronger and more chromosome-specific signals in in situ hybridization experiments than does a cloned alpha satellite DNA probe derived from the same chromosome. The results obtained indicate that the alpha-repeat monomer is composed of regions with different degrees of chromosome specificity.

Base Sequence↗
PubMed1989

Prenatal diagnosis of alpha-1-antitrypsin deficiency using polymerase chain reaction (PCR). Comparison of conventional RFLP methods with PCR used in combination with allele specific oligonucleotides or RFLP analysis.

Prenatal diagnosis of alpha 1-antitrypsin (AAT) deficiency can be performed in the 1st trimester of pregnancy. These diagnoses have been based on DNA technology using either RFLP analysis or hybridization with allele specific oligonucleotides. Several RFLPs within and flanking the AAT gene have been found to render most families informative. The polymerase chain reaction allows specific DNA sequences to be amplified up to ten million fold. Both sequences containing a specific mutation or an RFLP can be amplified by this method. We have compared conventional RFLP methods with PCR used in combination with allele specific oligonucleotides or RFLP analysis, in a case of prenatal diagnosis of AAT deficiency of the ZZ type.

Adult↗
PubMed1987

Improved methods for the detection of unique sequences in Southern blots of mammalian DNA by non-radioactive biotinylated DNA hybridization probes.

Biotinylated DNA hybridization probes offers a stable, cheap and non-radioactive alternative to probes labelled with 32P. Insufficient sensitivity has, however, up till now, been prohibitive for the use of such probes in detecting unique sequences in Southern blots of human DNA. By optimizing the steps in the procedure we have improved the sensitivity enough for such use. We have showed (1) that long probes (greater than 500 nucleotides) perform unproportionally better than short probes; (2) that a simple affinity labelling with avidin alkaline phosphatase conjugate performs better than laborious immunochemical systems; (3) that use of 3% BSA as blocking agent at 37 degrees C and the presence of 0.5 mol/l NaCl together with 1% BSA during the affinity labelling nearly eliminate background staining; (4) that a dramatic gain in sensitivity is gained by affinity labelling at pH 9.0 instead of 7.5; (5) that biotin-labelling can be highly reproducibly performed on a preparative scale with cheap and easily synthesized bio-11-dUTP in a two step nick-translation and (6) that biotinylated probes and hybridization mixtures can be stored for months and reused. The study has resulted in the presentation of a fast procedure, which is generally applicable to routine DNA diagnostic work, also in parts of the world where it is difficult to get a regular supply of 32P.

Base Sequence↗
PubMed1975

A hotel fire.

A hotel fire in Copenhagen claimed 35 victims of eight different nationalities. An account is given of some major aspects of the dental identification work, including a few case reports. This disaster became professionally important because the dental expert team was allowed a completely free hand. Eight dental experts cooperated closely in recording, photographing and radiographing dental conditions in the victims and thereby became able to establish that, with adequate facilities at hand, complete dental registration of a single victim required an average of three man-hours. Three of the experts subsequently cooperated in establishing comparable antemortem data on the known missing persons, in comparing the ante- and postmortem data sets, and in completing the necessary paper work. Here, it could be shown that a further two man-hours were required per victim. In a final report to the police it was proposed that---in any future case---such number of dentists should be assigned which, allowing three man-hours per victim, would enable the dental team to finish the oral autopsy of the given number of victims within five full working days, i.e. a minimum of two dentists per 30 victims. Two dentists will accomplish complete recording in less than half the time it will take any dentist working single-handed to finish it, so that the question of cost can hardly become an obstacle. It remains for the profession to make sure that an adequate number of knowledgeable dental experts are always available.

Adolescent↗
PubMed1975

[Plane crash].

Explore the source record for details and available documents.

Accidents, Aviation↗
PubMedDate not supplied

Preparation of bioconjugates by solid-phase conjugation to ion exchange matrix-adsorbed carrier proteins.

A solid-phase conjugation method utilizing carrier protein bound to an ion exchange matrix was developed. Ovalbumin was adsorbed to an anion exchange matrix using a batch procedure, and the immobilized protein was then derivatized with iodoacetic acid N-hydroxysuccinimid ester. The activated protein was conjugated with glutathione, the conjugation ratio determined by acid hydrolysis, and amino acid analysis performed with quantification of carboxymethyl cysteine. Elution of conjugates from the resin by a salt gradient revealed considerable heterogeneity in the degree of derivatization, and immunization experiments with the eluted conjugates showed that the more substituted conjugates gave rise to the highest titers of glutathione antibodies. Direct immunization with the conjugates adsorbed to the ion exchange matrix was possible and gave rise to high titers of glutathione antibodies. Conjugates of ovalbumin and various peptides were prepared in a similar manner and used for production of peptide antisera by direct immunization with the conjugates bound to the ion exchanger. Advantages of the method are its solid-phase nature, allowing fast and efficient reactions and intermediate washings, and the ability to release conjugates from the solid phase under mild conditions.

Adjuvants, Immunologic↗