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P Hoff-Olsen

Publications and source records attributed to P Hoff-Olsen.

9 recordsLinked to original sources
PubMed2001

Microsatellite stability in human post-mortem tissues.

Human identification and forensic criminal casework may involve DNA profiling of decomposed material. Somatic microsatellite (STR) instability may lead to false exclusions and theoretically to false inclusions, both in criminal cases and in human identification. Hence, the somatic and postmortal stability of the actual sequences is crucial to the reliability of such analyses. Somatic STR stability in human tissues has been documented in small series only and the effect of postmortal tissue decomposition on microsatellite stability remains to be elucidated. On this basis, we have systematically searched for somatic STR mutations in 26 deceased humans without signs of decomposition at autopsy and 25 autopsy cases with obvious signs of postmortal decomposition. A blood sample and six tissue samples were collected from each case. Seven STRs were chosen for study, the tetranucleotides HUMVWA31/A, HUMTH01, HUMF13A1, and HUMFES/FPS, and the hyperpolymorphic markers HUMAPOAI1, D11S554 and HUMACTBP2. Denaturing gel electrophoresis was performed on an ABD Prism 377 gene sequencer with Genescan 672 software (Applied Biosystems, Inc.). The bone DNA profile of each case was chosen as the standard DNA profile. All cases gave profiles from additional tissues. By intraindividual comparison of DNA profiles in the cases without signs of degradation we find that the short repetitive sequences under study are stable, that is without evidence of somatic mutations. The cases with varying degree of decomposition display postmortal microsatellite stability, we detect no somatic mutations or other possible postmortal changes that could lead to between-organ non-matches. In conclusion, PCR-based STR analyses are suitable in human identification and forensic casework dealing with different tissues, even when the substrate is heavily decomposed.

Autopsy↗
PubMed2001

Small bowel perforation as a complication of microsurgical lumbar diskectomy. A case report and brief review of the literature.

Ventral perforation is a rare complication of lumbar diskectomy. Injury to retroperitoneal vessels is the most common serious complication to such perforation. Ventral perforation with damage to the bowel is rarely reported. The authors present the first case report of injury to the small bowel during a microsurgical lumbar diskectomy. The case illustrates the importance of awareness of bowel injury as a possible complication of diskectomy. Possible pre- and postoperative considerations are also discussed. A brief review of the literature on bowel injuries after this common surgical procedure is also given.

Autopsy↗
PubMed1999

Extraction of DNA from decomposed human tissue. An evaluation of five extraction methods for short tandem repeat typing.

Hyperpolymorphic short tandem repetitive DNA sequences, STRs or microsatellites, have become widely used in human identification, particularly in criminal cases and in mass disasters. In such cases the substrates for the analyses may be decomposed biological material, a fact that has to be taken into account when choosing the appropriate casework methods. In this paper we report the evaluation of five different DNA extraction methods, namely the phenol-chloroform, the silica based, the InstaGene Matrix (BioTest), the glass fiber filter, and the Chelex based methods. The substrates for the analyses are decomposed human liver tissue specimens from forensic autopsy cases. Extracted DNA was quantified and DNA profiled by a set of seven STRs. We have compared laboratory time consumption and costs of the five methods, showing that the Chelex method is the more rapid and less expensive of the methods, the phenol-chlorophorm and silica extractions being the most time consuming and resource demanding ones. A full profile was obtained by the silica method in nine out of ten cases and this method failed to give a reliable type in four out of 70 STR analyses. The phenol-chlorophorm and the glass fiber filter methods failed in 16 analyses, the InstaGene Matrix (BioTest) in 25 and the Chelex extracts in 56 of the 70 STR analyses. By multiple logistic regression we show that the difference between the silica procedure and the other methods are statistically significant. In our hands, the silica gel extraction procedure is an obvious choice when the biological material available is decomposed human tissue--even if this procedure is one of the more laborious ones.

Autolysis↗
PubMed1998

Sudden death in two patients with epilepsy and the syndrome of inappropriate antidiuretic hormone secretion (SIADH).

We report two cases with complex partial and secondarily generalized seizures, both on oxcarbazepine and vigabatrin, with additional lamotrigine in one case. Both died in a manner resembling SUDEP, i.e. suddenly, unexpectedly, probably following a seizure with pulmonary oedema at autopsy. Both had SIADH. A number of drugs may cause SIADH, among them carbamazepine and oxcarbazepine. A search for SIADH in patients on carbamazepine and oxcarbazepine, and in cases of sudden death in epilepsy, is recommended.

Adolescent↗
PubMed1998

Variation in mutation rate and direction between tetranucleotide STR loci in human colorectal carcinomas.

Replication error (RER) is defined as mutation events in repetitive DNA segments. To investigate further the RER phenomenon and reveal any differences in mutation outcome between different short tandem repeat (STR) loci, we have investigated the somatic mutation rate and the size distribution of new tumour alleles in four tetranucleotide STRs in a large material of unselected colorectal adenocarcinomas. DNA was extracted from the blood and carcinomas of 217 patients. All blood/tumour pairs were analysed using the STRs HUMTHO1, HUMFES/FPS, HUMVWA31/A and HUMF13A1. Mutations are detected at all four loci. There are substantial differences in mutation rate and mutation direction (i.e. expansion versus contraction) between different STR loci. In all four STRs, the majority of events represent gain or loss of a single repeat. Almost all new tumour alleles correspond to known alleles in a population database, indicating that these are also composed of integers of the four base pair repeat. There is no statistically significant size bias in the mutating alleles as compared to the allelic distribution in the population database.

Adenocarcinoma↗
PubMed1995

Somatic mutations in VNTR-locus D1S7 in human colorectal carcinomas are associated with microsatellite instability.

To elucidate mutation mechanisms in hypervariable VNTR loci, we have studied somatic mutation events with the minisatellite probe MS1 (VNTR locus D1S7) in 224 colorectal carcinomas (CRC). The D1S7 locus consists of a 9-basepair (bp) repeat unit. The copy number varies from about 100 to 2000, and the germline mutation rate is high. Here we demonstrate a high D1S7 somatic mutation rate in CRC (37/224), higher than indicated earlier by others. We also demonstrate that the most frequent mutational event by far (n = 34) involves small reductions in VNTR fragment size (median loss 22 repeat units, range 2-154), furthermore, in one-half of these cases, this event is biallelic. We wanted to test whether these somatic mutations mirror the same genetic instability as seen by RER (replication error), a phenomenon recently described in tumour DNA from both sporadic and familial cases of CRC. All blood/tumour DNA pairs displaying MS1 mutation (n = 37) as well as 37 randomly selected pairs without MS1 mutation were tested with four tetranucleotide short tandem repeats (STRs, microsatellites). There is a strong association between mutations at the D1S7 locus and the occurrence of new STR alleles (P < 0.001). This is the first report of the existence of a minisatellite as a marker for genetic instability/RER in colorectal carcinomas. The findings may also cast light upon the mechanism for somatic mutations in this minisatellite.

Adenocarcinoma↗
PubMed1994

[Splenectomy and pneumococcal vaccine. How to follow-up?].

The authors describe the case of an otherwise healthy man who died from pneumococcal septicemia 18 years after having undergone splenectomy. It is widely accepted that splenectomized patients run increased risk of serious bacterial infections. Meningitis and septicemia caused by encapsulated organisms, especially Streptococcus pneumoniae, are most important in this respect, with a reported mortality of 30-60%. Since 1977, splenectomized patients have been offered pneumococcal vaccine as a routine, but persons who was splenectomized before 1977 are not identified, and run an unknown risk of serious infectious disease. Possible approaches to this problem of identification are discussed.

Adult↗
PubMed1993

Human VNTR mutation and sex.

Seven hypervariable VNTR loci have been studied in about 1200 parent/child pairs about equally divided between the sexes. Mutations were observed with all seven probes, the total number being 71. Fourty-four of these involved increased fragment length. Gains in fragment length were on average larger than losses. These findings indicate that mutation might be a basis for evolutionary expansion of VNTR fragment length. For five probes YNH24 (D2S44), MS31 (D7S21), g3 (D7S22), MS43A (D12S11), and CMM101 (D14S13), mutation rates were relatively low (less than 1%) with no obvious sex difference. MS1 (D1S7) mutation frequencies were substantially higher, with a tendency towards a higher paternal than maternal mutation rate (5.4% and 2.0%, respectively). The probe B6.7 (provisionally assigned to chromosome 20) exhibits about five times higher paternal than maternal mutation rates. The mutation rate of 7.6% in paternal chromosomes is among the highest reported in any VNTR locus. These findings could indicate that while low-mutant VNTRs might reflect meiotic crossover, mutation events in high-mutant loci could more often be caused by other mechanisms during cell division.

Biological Evolution↗