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Biomedical subjects

P Gill

Publications and source records attributed to P Gill.

At least 19 recordsLinked to original sources

Spontaneous prolonged hypertonic uterine contractions (essential uterine hypertonus) and a possible infective etiology.

The management of a pregnant woman presenting with prolonged hypertonic uterine contractions (essential uterine hypertonus) and mildly elevated temperature at term is described. Histology of the placenta, cord and membranes, following delivery, revealed evidence of chorioamnionitis, funisitis and deciduitis. Our findings raise the possibility that essential uterine hypertonus may have an infective or inflammatory component to its etiology.

Adult↗

DNA Commission of the International Society of Forensic Genetics: recommendations on forensic analysis using Y-chromosome STRs.

During the past few years, the DNA Commission of the International Society of Forensic Genetics has published a series of documents providing guidelines and recommendations concerning the application of DNA polymorphisms to the problems of human identification. This latest report addresses a relatively new area - namely, Y-chromosome polymorphisms, with particular emphasis on short tandem repeats (STRs). This report addresses nomenclature, use of allelic ladders, population genetics and reporting methods.

Alleles↗

A comparison of the characteristics of profiles produced with the AMPFlSTR SGM Plus multiplex system for both standard and low copy number (LCN) STR DNA analysis.

DNA STR profiles have been generated from 1 ng and low copy number (LCN) templates using 28 and 34 cycles of amplification, respectively. Characteristics which facilitate the interpretation of profiles, such as heterozygous balance, allelic dropout and stutter proportions have been quantified. We demonstrate that a reduction in DNA template coupled with an increase in amplification cycle number produces an increased rate of allelic dropout out which can be correlated to the peak areas of those alleles observed. In addition, the LCN conditions increase the degree of peak area asymmetry observed from heterozygotes and the size range of stutters. Analysis of the data allows us to develop sets of guidelines appropriate for interpreting both single and mixed DNA profiles.

Alleles↗

Results of a collaborative study of the EDNAP group regarding the reproducibility and robustness of the Y-chromosome STRs DYS19, DYS389 I and II, DYS390 and DYS393 in a PCR pentaplex format.

A collaborative exercise was carried out by the European DNA Profiling Group (EDNAP) in the frame work of the STADNAP program, i.e. standardization of DNA profiling in Europe, in order to evaluate the performance of a Y-chromosome STR pentaplex, which includes the loci DYS19, DYS389 I and II, DYS390 and DYS393 and to determine whether uniformity of results could be achieved among different European laboratories. Laboratories were asked to analyze the five Y-STRs using singleplex and multiplex conditions in three bloodstains and one mixed stain (95% female and 5% male). All the laboratories reported the same results even for the mixed stain included in the exercise. This demonstrates the reproducibility and robustness of Y-chromosome STR typing even with multiplex formats and proves the usefulness of Y-STR systems for analyzing mixed stains with a male component.A total of 930 male samples from 10 different populations from Europe were also analysed for all the loci included in the pentaplex. Eight of these ten populations also included haplotype data. As for single gene analysis, haplotype diversity was higher in Germany and Italy and lower in Western European countries and Finland. Pairwise haplotype analysis shows the Finnish departure from the rest of the populations and a relatively homogeneity in the other European populations with F(ST) estimates lower than 0.05.UPGMA analysis shows an association of Western European population (Ireland, UK, Portugal and Galicia) on the one hand and central European populations on the other.

Blood Stains↗

Sequenced allelic ladders and population genetics of a new STR multiplex system.

The advent of PCR technology and use of short tandem repeat (STR) loci improves throughput and reduces costs whilst a high level of discrimination can be achieved. A new system, comprising seven STRs, was developed to compliment the existing systems. This paper describes the preparation of allelic ladders of the most commonly observed alleles of a new STR multiplex system (third generation; TGM multiplex); all alleles have been sequenced. Meioses studies estimated a mutation rate of 0-0.4% across loci. Statistical independence was investigated by employing exact tests; chi(2)-tests and excess homozygosity tests. The results demonstrated that the allele proportions do not differ from those expected and that there was no consequential dependence between loci. The discriminating power of the system was examined using 295 Caucasian, 140 Afro-Caribbean and 212 Asian unrelated samples, and was found to be approximately 1 in 50 million, 1 in 85 million and 1 in 20 million for each of these groups, respectively.

Alleles↗

Sizing short tandem repeat alleles in capillary array gel electrophoresis instruments.

A 96-capillary array gel electrophoresis Applied Biosystems 3700 instrument has been used to analyse AMPF/STR SGM Plus short tandem repeat (STR) loci for forensic applications. This multiplex consists of ten STR loci plus the Amelogenin locus and currently forms the basis of the UK National DNA database that currently holds more than 1 million profiles. Of particular interest is the accuracy of allele designation that is determined by comparison with standard control allelic ladder markers. Some loci have higher standard deviations than others. In particular the high-molecular-weight HUMFIBRA alleles have high standard deviations of the order of 0.15 and it is these alleles that are most likely to be misdesignated. However, this risk is minimised by the analysis of at least five different allelic ladders across the array to estimate the mean size of each allele. In conjunction with this, a series of guidelines that can be programmed into expert systems are used to minimise risks of misdesignation. The efficacy of the procedures utilised are tested by computer simulation and demonstrated to be robust.

Alleles↗

DNA commission of the International Society of Forensic Genetics: recommendations on forensic analysis using Y-chromosome STRs.

During the past few years the DNA commission of the International Society of Forensic Genetics has published a series of documents providing guidelines and recommendations concerning the application of DNA polymorphisms to the problems of human identification. This latest report addresses a relatively new area, namely Y-chromosome polymorphisms, with particular emphasis on short tandem repeats (STRs). This report addresses nomenclature, use of allelic ladders, population genetics and reporting methods.

Alleles↗

An assessment of the utility of single nucleotide polymorphisms (SNPs) for forensic purposes.

This paper assesses the use of single nucleotide polymorphisms (SNPs) for forensic analysis. It demonstrates that relatively small arrays of approx. 50 loci are comparable to existing short tandem repeat (STR) multiplexes. A quantitative test, however, is a prerequisite for mixture interpretation. In addition, as the mixture proportion becomes low, it will be necessary to distinguish between the allele and background. Relatively small biallelic arrays are also suitable to distinguish between closely related individuals such as brothers.

Alleles↗

Pre-emptive analgesia with local anaesthetic for herniorrhaphy.

There is little evidence that local anaesthetics produce pre-emptive analgesia and one reason may be the short duration of action of the drugs studied. We examined the pre-emptive analgesic effect of a bupivacaine field block on postoperative pain in 40 patients following herniorrhaphy in a double-blind, randomised trial. Patients received the block either after induction but before surgery, or after surgery but before the end of anaesthesia. There was no difference in pain scores or analgesic consumption up to 7 days after surgery between the two groups. We have demonstrated that bupivacaine does not appear to provide significant pre-emptive analgesia following a field block for herniorrhaphy. This study does not support the hypothesis that pre-emptive analgesia with local anaesthetic depends upon the duration of action of the drug.

Adolescent↗

Virulence properties and serotypes of Shiga toxin-producing Escherichia coli from healthy Australian slaughter-age sheep.

A group of 1,623 ovine fecal samples recovered from 65 geographically distinct mutton sheep and prime lamb properties across New South Wales, Australia, were screened for the presence of Shiga toxin-producing Escherichia coli (STEC) virulence factors (stx(1), stx(2), eaeA, and ehxA). A subset was cultured for STEC isolates containing associated virulence factors (eaeA and/or ehxA), which were isolated from 17 of 20 (85%) and 19 of 20 (95%) tested prime lamb and mutton sheep properties, respectively. STEC isolates containing stx(1), stx(2), and ehxA were most commonly isolated (19 of 40 flocks; 47.5%), and this profile was observed for 10 different serotypes. Among 90 STEC isolates studied, the most common serotypes were O91:H(-) (22 isolates [24.4%]), O5:H(-) (16 isolates [17.8%]), O128:H2 (11 isolates [12.2%]), O123:H(-) (8 isolates [8.9%]), and O85:H49 (5 isolates [5.6%]). Two isolates (2.2%) were typed as O157:H(-). A total of 78 of 90 STEC isolates (86.7%) expressed Shiga toxin in Vero cell culture and 75 of 84 ehxA-positive isolates (89.3%) expressed enterohemolysin on washed sheep blood agar. eaeA was observed in 11 of 90 (12.2%) ovine STEC isolates, including serotypes O5:H(-), O84:H(-), O85:H49, O123:H(-) O136:H40, and O157:H(-). Although only 2 of 90 isolates were typed as O157:H(-), the predominant serotypes recovered during this study have been recovered from human patients with clinical disease, albeit rarely.

Abattoirs↗

Retroviral vectors bearing IgG-binding motifs for antibody-mediated targeting of vascular endothelial growth factor receptors.

Targeting retroviral vectors to tumor vasculature is an important goal of cancer gene therapy. In this study, we report a novel targeting approach wherein IgG-binding peptides were inserted into the Moloney murine leukemia virus (MuLV) envelope (env) protein. The modifications on the viral env included replacement of the entire receptor binding region of the viral env with protein A (or ZZ) domains. The truncated env incorporating IgG-binding motifs (known as proteins) provided the targeting function, while the co-expressed wild-type (WT) env protein enabled viral fusion and cell entry. An anti-human VEGF receptor (Flk-1/KDR) antibody served as a molecular bridge, directing the retroviral vector to the endothelial cell. Hence, the IgG-targeted vectors bound to the Flk-1/KDR antibody which in turn bound to VEGF receptors on Kaposi sarcoma, KSY1, endothelial cells. The net effect was increased viral fusion and infectivity of IgG-bound retroviral vectors when compared to non-targeted vectors bearing WT env alone. These data provide the proof of concept that IgG-binding vector/VEGF receptor antibody complexes may be used to enhance retroviral gene delivery to activated endothelial cells.

Amino Acid Sequence↗

Application of low copy number DNA profiling.

Low copy number (LCN) DNA profiling is a technique sensitive enough to analyze just a few cells. When this kind of analysis is carried out, special considerations are needed to interpret the results. In particular, it is important to consider the implications of allele dropout and the possibility of contamination from a laboratory source. A rationale for interpreting LCN DNA is described.

DNA Fingerprinting↗

Improving detection of venous thromboembolism. New technology holds promise for early, precise diagnosis.

In recent years, a number of modalities have been evaluated for the diagnosis of venous thromboembolism. The role of these modalities is still evolving. While ventilation-perfusion scanning is important in the diagnosis of venous thromboembolism, spiral CT scanning, MRI, and D-dimer assays are now being used more often, either exclusively or in combination with ventilation-perfusion scanning. A number of diagnostic algorithms using these modalities are currently being evaluated. Regardless of which diagnostic approach is used, the clinician must be aware of some key limitations. Spiral CT scanning has gained popularity because it is noninvasive and can rapidly identify other cardiopulmonary diseases that mimic pulmonary embolism. Its use has been limited because of its inability to detect subsegmental pulmonary emboli. D-dimer assays offer promise as rapid, inexpensive screening tools. However, the wide variability in assay performance has limited its usefulness. We recommend that if D-dimer assays are to be used in a diagnostic algorithm, the clinician be aware of the details of the assay. At present, lack of data precludes use of MRI as a primary diagnostic tool for detection of venous thromboembolism.

Fibrin Fibrinogen Degradation Products↗

Lack of serologic association of human herpesvirus-8 (KSHV) in patients with monoclonal gammopathy of undetermined significance with and without progression to multiple myeloma.

Because human herpesvirus-8 (HHV-8) DNA has been found in multiple myeloma (MM) patients by polymerase chain reaction, it was suggested that HHV-8 may play a role in the transformation of monoclonal gammopathy of undetermined significance (MGUS) to MM. Therefore, 362 MGUS sera with and without progression to MM were tested for IgG antibody to HHV-8. Only 7.8% of the MGUS sera contained HHV-8 antibody to lytic proteins, and IgG antibody to HHV-8 latent antigen was even lower than lytic antibody (2.9%). No differences were observed in the distribution of antibody to HHV-8 in sera from MGUS patients who progressed to MM. The seroprevalences of HHV-8 in MGUS (7.8%), MM (5.4%), and healthy donors (5.9%) were similar, thus arguing for the lack of epidemiologic evidence of HHV-8 participation in the pathogenesis of MM. MGUS patients were immune competent in response to Epstein-Barr virus (EBV) infection because 97% contained antibody to EBV virus capsid antigen.

Herpesvirus 8, Human↗

An investigation of the rigor of interpretation rules for STRs derived from less than 100 pg of DNA.

By increasing the PCR amplification regime to 34 cycles, we have demonstrated that it is possible routinely to analyse <100 pg DNA. The success rate was not improved (without impairing quality) by increasing cycle number further. Compared to amplification of 1 ng DNA at 28 cycles, it was shown that increased imbalance of heterozygotes occurred, along with an increase in the size (peak area) of stutters. The analysis of mixtures by peak area measurement becomes increasingly difficult as the sample size is reduced. Laboratory-based contamination cannot be completely avoided, even when analysis is carried out under stringent conditions of cleanliness. A set of guidelines that utilises duplication of results to interpret profiles originating from picogram levels of DNA is introduced. We demonstrate that the duplication guideline is robust by applying a statistical theory that models three key parameters - namely the incidence of allele drop-out, laboratory contamination and stutter. The advantage of the model is that the critical levels for each parameter can be calculated. This information may be used (for example) to determine levels of contamination that can be tolerated within the strategy employed. In addition we demonstrate that interpreting one banded loci, where allele dropout could have occurred, using LR=1/2f(a) was conservative provided that the band was low in peak area. Furthermore, we demonstrate that an apparent mis-match between crime-stain and a suspect DNA profile does not necessarily result in an exclusion. The method used is complex, yet can be converted into an expert system. We envisage this to be the next step.

Alleles↗