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Biomedical subjects

P Gill

Publications and source records attributed to P Gill.

At least 19 recordsLinked to original sources
PubMed1992

A rapid polymerase chain reaction method for identifying fixed specimens.

DNA profiling analysis of preserved tissue samples was achieved by using an extraction method which incorporated the use of a chelating resin "Chelex" to chelate inhibitory polyvalent metal ions. An automated sequencer was used to estimate sizes of low molecular weight trimeric and tetrameric microsatellites labelled with fluorescent dyes. The entire analysis can be completed within 48h. Probabilities of chance association using two microsatellites were calculated as ranging between 10(-2) and 10(-4). The methods described have considerable potential for use in routine genetic analysis of preserved samples.

Alleles↗
PubMed1992

Characterisation of HLA DQ alpha for forensic purposes. Allele and genotype frequencies in British Caucasian, Afro-Caribbean and Asian populations.

Allele and genotype frequencies for British Caucasian, Afro-Caribbean and Asian populations were determined for a total of over 600 unrelated individuals at the HLA-DQ alpha locus. These were analysed by polymerase chain reaction amplification of the DNA followed by hybridisation to allele specific oligonucleotide probes in a reversed dot-blot test. Six different alleles were detected and the allele distributions for the 3 populations analysed displayed significant differences. However, the British Caucasian genotypes were statistically very similar to previously published data from US Caucasians as were British Afro-Caribbean genotype frequencies with US Black data. In Caucasians the allele frequencies ranged from 5.2% to 26.9% with a power of discrimination of 0.93. DQ alpha genotype frequencies of Caucasian and Afro-Caribbean populations do not deviate from Hardy-Weinberg equilibrium. However, the Asian data displayed significant deviation due to excess homozygotes.

Alleles↗
PubMed1992

Identification of human remains by amplification and automated sequencing of mitochondrial DNA.

The highly decomposed remains of a corpse were identified by the amplification and direct sequencing of mitochondrial (mt) DNA. Degraded DNA was extracted from bone fragments and a necrotic skin sample and amplified at 2 hypervariable segments within the mitochondrial non-coding region using 2 rounds of nested PCR. Both strands of the amplified regions were sequenced and compared with each other to ensure fidelity of the data. Sequences from the bone and skin were found to be identical and matched data generated from a blood sample provided by a presumptive sister of the deceased. Thus, this evidence was consistent with the sister and the deceased being related.

Base Sequence↗
PubMed1992

Rapid immunoassays for the measurement of immunoglobulin G subclass concentration in immunoglobulin preparations and human serum.

Enzyme immunoassays (EIA) capable of determining total IgG1, IgG2, IgG3 and IgG4 subclass concentrations in human serum preparations have been developed. Subclass-specific monoclonal antibodies (mAbs) are bound to polyacrylamide bead-conjugated anti-mouse immunoglobulin antibodies. Bound immunoglobulins are detected with a peroxidase-conjugated anti-IgG antibody or a biotin-conjugated anti-IgG antibody followed by peroxidase streptavidin. The standard curves were found to be linear in the regions 16.0-2.0 micrograms/ml for IgG1, 4.0-0.5 micrograms/ml for IgG2, 0.4-0.06 micrograms/ml for IgG3 and 0.25-0.05 micrograms/ml for IgG4. Coefficient of variation (CV) values range from 0.32-7.32% for IgG1, 0.66-4.85% for IgG2, 1.62-6.85% for IgG3 and 0.05-6.47% for IgG4 standard curves. The inter-assay variability for the control human serum samples was 9.6% for IgG1, 6.7% for IgG2, 9.5% for IgG3 and 6.8% for IgG4.

Adolescent↗
PubMed1992

A report of an international collaborative experiment to demonstrate the uniformity obtainable using DNA profiling techniques.

This paper describes a collaborative exercise intended to demonstrate whether uniformity of DNA profile results could be achieved between different European laboratories. It was shown that this goal can be obtained provided that a common protocol is followed (specifically the use of a common electrophoretic buffer as being the most important parameter). Generally, lower molecular weight loci (with lower molecular weight fragments) such as YNH24 perform better than higher molecular weight loci such as MS43a. The results of the exercise are discussed in relation to the objectives of the European DNA profiling group (EDNAP).

Autoradiography↗
PubMed1992

Anti-hepatitis C virus (HCV) screening at a Canadian Red Cross center: significance of a positive c100 HCV enzyme-linked immunosorbent assay.

The c100 hepatitis C virus (HCV) enzyme-linked immunosorbent assay (ELISA) has been used to screen blood donors to prevent transfusion-associated non-A,non-B hepatitis. This test is not specific, and only about 25 percent of c100 HCV ELISA-positive blood samples appear to transmit hepatitis C. However, the intensity of the ELISA (sample/cutoff ratio [S/C], greater than 2) could identify a subpopulation of donors that are at high risk for transmitting hepatitis. Blood samples from 20,186 volunteer blood donors at a Canadian Red Cross blood transfusion center were screened for antibodies to HCV using the c100 HCV ELISA. Fifty-nine (0.3%) of these donors were repeatably reactive on ELISA. When their samples were tested with the c100 recombinant immunoblot assay (RIBA) and second-generation RIBA (RIBA-2), 26 (44%) and 31 (52%) samples, respectively, were found to be positive. Thirty-three of the 59 ELISA-reactive donors had an S/C greater than 2. Of these 33 donors, 30 (91%) had elevated alanine aminotransferase (ALT), 27 (82%) were RIBA-2 positive, and 22 (67%) had risk factors for hepatitis. In contrast, of the 26 ELISA-reactive donors with S/C less than 2, only 7 (27%) had elevated ALT, and 4 (15%) were RIBA-2 positive and also had high risk factors for hepatitis. Thus, while the HCV ELISA may lack specificity, its intensity can serve to identify a subgroup of donors that are at high risk for transmitting hepatitis.

Adult↗
PubMed1992

Automated DNA profiling by fluorescent labeling of PCR products.

DNA profiling has been automated by the fluorescent tagging of amplified variable number tandem repeat (VNTR) loci. This was achieved by the use of fluorescently labeled primers in the amplification of 10 ng of genomic DNA, coupled with laser detection of the products during electrophoresis. The PCR products are sized by co-electrophoresing a standard size ladder mixed with every sample, thereby eliminating errors in size estimation caused by lane-to-lane differences in migration rate. This increases the precision of VNTR characterization and enables alleles that differ by a single 15-bp repeat to be resolved. The system is capable of high throughput: Twenty-four samples are electrophoresed and analyzed within 6 hr. Also, because four different dyes are available, three different loci can be simultaneously characterized with the fourth dye used for the internal standard. Approximately 100 unrelated British caucasians were analyzed at the loci D1S80, D17S5, and ApoB. The probabilities of two unrelated individuals matching by chance (pM) at these three loci were determined to be 0.065, 0.040, and 0.069, respectively, with a combined pM of 1.8 x 10(-4).

DNA↗
PubMed1992

Strategies for automated sequencing of human mitochondrial DNA directly from PCR products.

A rapid, robust and sensitive method has been developed for the amplification and direct sequencing of human mitochondrial DNA. A 403-bp hypervariable segment was amplified by two successive rounds of nested PCR. This was then sequenced by the dideoxy chain termination method using dye-labeled universal sequencing primers in conjunction with an automated DNA sequencer. This paper describes the assessment of four different strategies for this amplification and sequencing process. Optimal results were obtained by immobilizing the biotinylated PCR product on Dynabeads followed by solid-phase sequencing with Sequenase. Degraded samples and those containing trace amounts of DNA such as extracts from hair shafts can be analyzed by this method.

Automation↗
PubMed1992

Effect of exercise on uterine activity in the patient in preterm labor.

Preterm labor patients are at risk for physiologic complications associated with long-term bed rest. Although conditioning exercise programs are recommended for patients confined to bed rest, no studies have been reported that have evaluated the effects of exercise on uterine activity in women with preterm labor. A pilot study with 10 women was conducted to evaluate the short-term effects of exercise with a protocol involving pretesting and posttesting of uterine activity. The results indicated minimal changes in the frequency of uterine contractions after exercise. Future research is recommended with larger and more diverse samples to evaluate both short- and long-term effects of exercise throughout high-risk pregnancies.

Adult↗
PubMed1991

Ditiocarb sodium (diethyldithiocarbamate) therapy in patients with symptomatic HIV infection and AIDS. A randomized, double-blind, placebo-controlled, multicenter study.

We randomized 389 symptomatic patients with human immunodeficiency virus (HIV) infection to ditiocarb sodium (400 mg/m2 orally for 24 weeks) or a placebo. Patients were well balanced according to Centers for Disease Control (CDC) group, CD4+ cell number, and duration of disease prior to entry. Ten new acquired immunodeficiency syndrome (AIDS)-defining opportunistic infections occurred in the treated patients and 21 in the controls. Reduction of new opportunistic infections in the ditiocarb group was significant in all patients (relative risk [RR], 0.44) and in patients with AIDS (CDC groups IV-C1 and IV-D) (RR, 0.12). The size of the effect of ditiocarb was maintained when data were reanalyzed after exclusion of a patient who progressed to Pneumocystis carinii pneumonia who was not strictly CDC-defined (RR, 0.46), or when considering as new opportunistic infections three events, which were clinically active at entry, but for which the definitive diagnosis was made during study (RR, 0.49). The administration of ditiocarb did not induce any major adverse clinical or biological reactions. We conclude that, in this study, ditiocarb was safe and reduced the incidence of opportunistic infections in patients with symptomatic HIV infection.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Repair of cartilaginous fractures during chick limb development.

The embryonic chick wing has been used extensively in experimental analyses of the mechanisms involved in limb development. This study employs the embryonic wing in an examination of the possible origin of congenital pseudoarthrosis, a poorly understood limb disorder. To this end, chick radii were fractured in the middiaphysis prior to the onset of osteogenesis (6.5-7 days of incubation). The subsequent development of the fractured elements was examined using both whole mount preparations and histology. Callus cartilage did not form around any of the fractures. Nonetheless, the majority (29 of 33 specimens) of fractures united during primary osteogenesis (within 24-36 h of the operation), with bone formation occurring both across the fracture site and also over the cut ends of the cartilage. In addition, bones that exhibited a configuration similar to that described as giving rise to a type II congenital pseudoarthrotic condition were obtained. Typically, these bones showed an "hourglass" constriction midshaft and anterior bowing. These results suggest that the embryonic chick limb may serve as a useful experimental model system for the investigation of this congenital limb disorder.

Animals↗
PubMed1990

Treatment of advanced Kaposi's sarcoma using a combination of bleomycin and vincristine.

Eighteen patients with disseminated AIDS-related Kaposi's sarcoma (KS) and compromised bone marrow function were treated with a relatively non-myelosuppressive regimen of bleomycin and vincristine (BV). At study entry, the patients presented with the following median laboratory values: hemoglobin of 9.5 g/dl, granulocyte counts of 1,173/mm3, platelet counts of 218,000/mm3, and CD4 lymphocyte counts of 58/mm3. All patients had extensive Kaposi's sarcoma. Nine patients had visceral involvement: four with pulmonary involvement, two with gastrointestinal involvement, and three with both. Following a median number of seven cycles of biweekly chemotherapy, complete or partial tumor responses were achieved in 13 patients (72%). Two patients experienced bleomycin-induced skin toxicities, whereas 10 others (55%) experienced peripheral sensory neuropathy requiring vincristine dose reductions. Opportunistic infections had occurred in 11 patients prior to initiation of chemotherapy and in 16 after initiation of chemotherapy. Despite the frequent development of opportunistic infections, BV chemotherapy was relatively well tolerated and resulted in a high response rate in this patient population that presented with suboptimal marrow function and extremely low CD4 lymphocyte counts.

Acquired Immunodeficiency Syndrome↗
PubMed1978

Urinary tract infection in young women, with special reference to Staphylococcus saprophyticus.

Acute urinary tract infections in young women attending a clinic for sexually transmitted diseases were caused by the same bacteria, in the same proportions, as those that caused infections in women students. Staphylococcus saprophyticus biotype 3 (formerly called Micrococcus subgroup 3) was the commonest organism after coliform bacilli and caused about 30% of the infections. It was uncommon in women over 25 years of age and rarely caused asymptomatic bacteriuria in pregnancy. Most infections, irrespective of the causative organism, started soon after sexual intercourse, but neither the staphylococci nor the other organisms were associated with promiscuity, as judged by numbers of sexual partners or the incidence of sexually transmitted diseases. There was no evidence that the staphylococci were sexually transmitted. The reasons for the virulence of Staph. saprophyticus and its predilection for the urinary tract of young women remain unknown.

Adult↗
PubMed1978

Comparison of "invasive" and "non-invasive" strains of Staphylococcus epidermidis by phage typing.

Seventy strains of coagulase-negative staphylococci isolated from blood of patients together with 41 strains of these bacteria isolated from the skin were typed by three different phage sets. Different percentages of phage typability by compared phage sets were found. Blood culture strains showed phage pattern Ph10/U14/U16 while other strains were of different phage patterns.

Bacteriophage Typing↗