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Biomedical subjects

Kathy Mann

Publications and source records attributed to Kathy Mann.

10 recordsLinked to original sources
PubMed2007

Minimal incision protocols for anesthesia, pain management, and physical therapy with standard incisions in hip and knee arthroplasties: the effect on early outcomes.

Dramatic early outcomes with "minimal incision" surgery are attributed to patient selection, perioperative management, and the surgical procedure. This study was one on 50 patients in a single surgeon's practice who underwent total hip and total knee arthroplasties with standard incisions. The first 25 patients had standard perioperative management, whereas the second 25 had the anesthesia, pain management, and physical therapy protocols described for minimal incision surgery. A dramatic reduction in the time it took to achieve the goals for discharge was observed in the second group. Most patients with the "mini" protocols were ready for discharge within 24 hours. The implications of these results are discussed.

Adult↗
PubMed2005

Increased missegregation and chromosome loss with decreasing chromosome size in vertebrate cells.

Chromosome engineering has allowed the generation of an extensive and well-defined series of linear human X centromere-based minichromosomes, which has been used to investigate the influence of size and structure on chromosome segregation in vertebrate cells. A clear relationship between overall chromosome size and mitotic stability was detected, with decreasing size associated with increasing loss rates. In chicken DT40, the lower size limit for prolonged mitotic stability is approximately 550 kb: at 450 kb, there was a dramatic increase in chromosome loss, while structures of approximately 200 kb could not be recovered. In human HT1080 cells, the size threshold for mitotic stability is approximately 1.6 Mb. Minichromosomes of 0.55-1.0 Mb can be recovered, but display high loss rates. However, all minichromosomes examined exhibited more segregation errors than normal chromosomes in HT1080 cells. This error rate increases with decreased size and correlates with reduced levels of CENP-A and Aurora B. In mouse LA-9 and Indian muntjac FM7 cells, the size requirements for mitotic stability are much greater. In mouse, a human 2.7-Mb minichromosome is rarely able to propagate a kinetochore and behaves acentrically. In Indian muntjac, CENP-C associates with the human minichromosome, but the mitotic apparatus appears unable to handle its segregation.

Animals↗
PubMed2005

Detection of mosaicism for primary trisomies in prenatal samples by QF-PCR and karyotype analysis.

OBJECTIVES: QF-PCR can be used to rapidly diagnose primary trisomy in prenatal samples. Our objectives were to estimate the prevalence of primary trisomy mosaicism for chromosomes 13, 18 or 21 in a cohort of prenatal samples, and to compare and contrast the detection of this mosaicism using both QF-PCR and karyotype analysis. METHODS: Data was collated from all prenatal samples displaying mosaicism for a primary trisomy between June 2000 and March 2004. Levels of mosaicism were estimated and samples were categorised according to the cell population in which the mosaicism was detected. RESULTS: In a total of 8983 samples, 18 samples (0.20%) displaying mosaicism were detected, including trisomy 13 (three samples), trisomy 18 (seven samples), trisomy 21 (seven samples) and mosaic triploidy (one sample). This included 7 amniotic fluid and 11 chorionic villus samples. Mosaicism was detected by QF-PCR in 12 samples and by karyotype analysis in 8 samples. CONCLUSIONS: QF-PCR can detect mosaicism when the abnormal cell line contributes at least 15% of the whole sample. Use of both karyotype and QF-PCR analysis leads to the detection of more cases of mosaicism than either test alone.

Adult↗
PubMed2005

Maternal cell contamination of prenatal samples assessed by QF-PCR genotyping.

OBJECTIVES: To establish the genotype of cultured cells from a cohort of amniotic fluid and chorionic villus samples, and compare this genotype with that obtained from uncultured material from the same sample, in order to assess the frequency and significance of maternal cell contamination of prenatal samples. METHODS: Quantitative fluorescence-polymerase chain reaction (QF-PCR) was carried out by amplification of microsatellite markers using fluorescence-labelled primers, followed by quantitative analysis of the allele peaks on a genetic analyser. A multiplex of 12 primer pairs for four loci on each of chromosomes 13, 18 and 21 was used. RESULTS: A total of 307 prenatal samples were tested. Of the 254 amniotic fluid samples, 39.8% had some degree of bloodstaining, ranging from 5% bloodstaining in the cell pellet to heavily bloodstained fluid. Uncultured samples were tested by QF-PCR analysis and the cultured cells were tested by both QF-PCR and karyotype analysis. Of the samples, 90.2% had the same single genotype on direct and cultured material. Two samples (0.65%) were mosaic for an aneuploidy cell line. A second genotype, interpreted as maternal cell contamination, was identified in direct and/or cultured preparations in 9.1% of samples, 17.8% of which were not bloodstained. Seven amniotic fluid samples (2.8%) showed maternal cell contamination in cultured material. CONCLUSIONS: For heavily bloodstained amniotic fluid samples, a maternal blood specimen may help interpret the results of rapid trisomy testing, followed by confirmation of the fetal origin of cultured cells. QF-PCR analysis has established a higher incidence of maternal cell contamination of cultured amniocytes than previous reports; the presence of MCC (maternal cell contamination) in cultured cells from samples with no bloodstaining underlines the need for karyotype analysis of more than one XX culture.

Adult↗
PubMed2005

Rapid prenatal diagnosis of aneuploidy using quantitative fluorescence-PCR (QF-PCR).

Molecular cytogenetic aneuploidy testing for pregnant women at increased risk of chromosome abnormality leads to rapid reassurance for those with normal results and earlier decisions on pregnancy management in the case of abnormality. We tested 9080 prenatal samples using a one-tube QF-PCR test for trisomies 13, 18, and 21; the abnormality rate was 5.9%. There were no misdiagnoses for non-mosaic trisomy. A sex chromosome multiplex was developed that detects structural sex chromosome abnormalities as well as aneuploidies. The sex chromosome test was targeted at pregnancies (272) with specific abnormalities suggestive of Turner syndrome; 13.2% showed 45,X, confirmed by follow-up analysis.

Aneuploidy↗
PubMed2004

Strategies for the rapid prenatal diagnosis of chromosome aneuploidy.

Rapid diagnosis of common chromosome aneuploidies in raised risk pregnancies, usually prior to full karyotype analysis, is now carried out in a number of European genetic centres; several techniques for detecting genomic copy number changes have been described. Prenatal diagnosis of genetic disease requires accurate and robust assays; the invasive procedures are associated with a risk of pregnancy loss and an abnormal result may lead to termination of the pregnancy. The testing of prenatal material (amniotic fluid, chorionic villi or, more rarely, fetal blood) is associated with specific problems, including the quality and quantity of the tissue and difficulties of interpretation due to phenomena such as maternal cell contamination and mosaicism. In addition, there are 24-h, high-throughput demands on centres offering such a service. The extent to which existing and proposed strategies, including different PCR-based assays, a multiplex ligation-dependent probe amplification approach, and microarrays, fulfil the requirements of rapid prenatal testing is discussed. In the past 3 years, we have tested 7720 prenatal samples for trisomies 13, 18 and 21 using a quantitative fluorescence-PCR (QF-PCR) approach. The abnormality rate was 5.7%. There were no misdiagnoses for nonmosaic trisomy, the amplification failure rate was 0.09% of samples, and 97% of samples received a report on the working day following sample receipt. Maternal cell contamination and mosaicism were also detected. Our data recommend a QF-PCR approach as the current method of choice for rapid aneuploidy testing.

Aneuploidy↗
PubMed2004

Multiplex ligation-dependent probe amplification using a completely synthetic probe set.

The recent development of multiplex ligation-dependent probe amplification (MLPA) has provided an efficient and reliable assay for dosage screening of multiple loci in a single reaction. However, a drawback to this method is the time-consuming process of generating a probe set by cloning in single-stranded bacteriophage vectors. We have developed a synthetic probe set to screen for deletions in a region spanning 18.5 Mb within chromosome 3q. In a pilot study, we tested 15 synthetic probes on 4 control samples and on 2 patients previously found to possess a heterozygous deletion in the region 3q26-q28. These synthetic probes detected deletions at all previously known deleted loci. Furthermore, using synthetic probes, the variability of results within samples was similar to that reported for commercially available M13-derived probes. Our results demonstrate that this novel approach to MLPA provides a generic solution to the difficulties of probe development by cloning; such synthetically generated probes may be used to screen a large number of loci in a single reaction. We conclude that the use of synthetic probes for MLPA is a rapid, robust, and efficient alternative for research (and potentially diagnostic) deletion and duplication screening of multiple genomic loci.

Chromosome Deletion↗
PubMed2003

In vivo somatic microsatellite mutations identified in non-malignant human tissue.

Microsatellite instability (MSI) has been described in cancer cells and in vitro cell lines, and meiotic changes in repeat length have also been documented. We report the novel observation of somatic microsatellite mutation (SMM) in normal human somatic cells in vivo, detected while genotyping 5767 prenatal samples (4640 amniotic fluid samples and 1127 chorionic villus biopsies) as a diagnostic test for exclusion of trisomy 13, 18 or 21. Quantitative fluorescence-PCR using a multiplex of 12 primer pairs, for four loci on each of the three chromosomes, was followed by fragment analysis on a capillary-based genetic analyser. Forty-seven (4.2%) chorionic villus samples and six (0.1%) amniotic fluid samples showed allelic mosaicism, interpreted as SMM. In four cases, analysis of parental blood samples confirmed the presence of a de novo allele. SMM was detected at all but two of the 12 loci tested, and the incidence of mutation increased with repeat length. Detection of SMM in chorionic villus samples may imply less rigorous correction of replication errors in these extra-embryonic tissues, and is likely to have been facilitated by clonal expansion in the small samples of tissue tested. The presence of the same phenomenon in six amniotic fluid samples would imply that in these pregnancies, the instability event had occurred early in embryogenesis. The results suggest that defective proof reading during DNA replication may be more common in non-malignant human somatic tissue than previously recognised.

Alleles↗
PubMed2003

Development and targeted application of a rapid QF-PCR test for sex chromosome imbalance.

OBJECTIVES: A QF-PCR test has been developed to diagnose sex chromosome imbalances in prenatal samples and has been applied to a diagnostic service. METHODS: The test uses a PCR multiplex with eight primer pairs: six X-chromosome polymorphic markers, including two markers from Xp (a region not included in previously published sex chromosome aneuploidy tests), one polymorphic marker for a locus common to the long arms of the X and Y chromosomes, and the non-polymorphic amelogenin marker. Homozygosity for all X-chromosome markers and the absence of the Y-chromosome amelogenin marker is highly likely (907 : 1) to represent monosomy X (Turner syndrome), but interphase FISH is always used to confirm such a result. RESULTS: Blind studies were carried out to validate the test and the first year of clinical use has been reported. Results are usually issued within one working day, and the test is more efficient than interphase FISH. CONCLUSIONS: The sex chromosome imbalance test has been targeted to prenatal samples displaying a clear ultrasound indication consistent with Turner syndrome, and has also been used to identify fetal sex in pregnancies at risk of inheriting a sex-linked molecular disorder. No misdiagnoses were made. It is concluded that QF-PCR can rapidly and accurately diagnose sex chromosome status and imbalances, reducing maternal anxiety and aiding in efficient pregnancy management.

Amelogenin↗