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Biomedical subjects

D E Leslie

Publications and source records attributed to D E Leslie.

15 recordsLinked to original sources
PubMed2002

Fragmentation of positronium in collision with He atoms.

The absolute cross section for the fragmentation of positronium in collision with He atoms has been measured. The results are compared with available theories. The longitudinal energy distributions of positrons resulting from fragmentation have also been determined and are found to display a peak situated just below half the residual energy. This is suggestive of the occurrence of "electron loss to the continuum" in which the two residual charged particles lie in a low relative-velocity Coulomb-continuum state.

Journal Article↗
PubMed1998

An Australian isolate of Mycobacterium shimoidei.

A case of Mycobacterium shimoidei in a 75 year old man is reported. He had been a smoker, with a past history of bullous emphysema and a lung abscess. He had a 12 month history of weight loss, night sweats, with increased cough and sputum, and progressive opacification of the left apex with cavity formation. Sputum repeatedly grew M. shimoidei, identification of which was confirmed with high-pressure liquid chromatography (HPLC). He was treated for 45 days with three drugs to which the organism was sensitive, but failed to respond. His death was attributed to mycobacterial infection.

Aged↗
PubMed1997

A large localized outbreak of Mycobacterium ulcerans infection on a temperate southern Australian island.

Mycobacterium ulcerans, the organism which causes Buruli or Bairnsdale ulcer, has never been isolated in culture from an environmental sample. Most foci of infection are in tropical regions. The authors describe the first 29 cases of M. ulcerans infection from a new focus on an island in temperate southern Australia, 1992-5. Cases were mostly elderly, had predominantly distal limb lesions and were clustered in a small region in the eastern half of the main town on the island. The authors suspected that an irrigation system which lay in the midst of the cluster was a source of infection. Limitation of irrigation was associated with a dramatic reduction in the number of new cases. These findings support the hypothesis that M. ulcerans has an aquatic reservoir and that persons may be infected directly or indirectly by mycobacteria disseminated locally by spray irrigation.

Adolescent↗
PubMed1996

The emergence of Mycobacterium ulcerans infection near Melbourne.

OBJECTIVE: To document the emergence of new foci of Mycobacterium ulcerans infection (Bairnsdale ulcer) in Victoria. METHODS: From data kept by one of us (JAH) and records from the Mycobacterium Reference Laboratory, Fairfield Hospital, we reviewed cases of M. ulcerans infection in Victoria between 1980 and 1995, and identified those apparently acquired outside the east Gippsland endemic region. A case was defined as a person with a lesion suggestive of M. ulcerans infection, from which the organism had been cultured or, in the absence of culture information, from which a histological specimen characteristic of M. ulcerans infection had been obtained. RESULTS: We identified 45 people who appeared to have acquired their infections in Victoria but outside the east Gippsland region. A new focus appeared on the northern shores of Western Port, near Melbourne, in 1982, and there was a dramatic increase in cases between 1991 and 1994 associated with foci on Phillip Island, and in the Frankston-Langwarrin area of outer suburban Melbourne. Single cases came from Crib Point, Narre Warren and Bendigo. CONCLUSIONS: There have been at least three new foci of M. ulcerans infection within 80 km of Melbourne since 1982. Victorian clinicians should consider the possibility of Bairnsdale ulcer when dealing with unusual skin lesions.

Adolescent↗
PubMed1996

Evaluation of the Roche Amplicor polymerase chain reaction system for detection of Mycobacterium tuberculosis complex in specimens.

Roche Diagnostic Systems Inc. have recently developed a commercial PCR (Amplicor) for direct amplification of Mycobacterium tuberculosis Complex (MtbC) from sputum and bronchial washes. Detection of MtbC specific sequence is achieved by hybridization with an oligonucleotide probe. The aim of this study was to compare the Amplicor PCR system for detection of MtbC with microscopy, culture and an in-house PCR method. The commercial assay correctly identified 35/37 microscopy positive specimens compared to 34/37 with the in-house method and 7/13 microscopy negative, culture positive samples compared to 2/13 with the in-house procedure. Negative PCR results were obtained for 32 culture negative specimens and 6 specimens which yielded mycobacteria other than MtbC, indicating a specificity of 100%. The sensitivity of the commercial assay was determined to be approximately 10 organisms compared to 100 organisms with the in-house method. The Amplicor PCR system is specific, sensitive and easy to perform. It also has the advantages of being standardized and quality controlled.

Bacteriological Techniques↗
PubMed1996

Pitfalls in the use of random amplified polymorphic DNA (RAPD) for fingerprinting of gram negative organisms.

Two arbitrary PCR primers for random amplified polymorphic DNA (RAPD) bacterial fingerprinting were used to test factors which may affect RAPD PCR results. These primers have been used in previously published RAPD fingerprinting studies. As expected, the MgCl2 concentration and template concentration in the reaction mixture may affect the RAPD banding patterns. The results obtained were not comparable between runs when using the Hybaid thermal cycler when all other conditions were kept constant. Addition of DMSO, gelatin and repeated subculturing did not appear to affect the banding patterns. A second set of primers directed against known repetitive sequences in Gram negative bacteria (REP1/REP2 and ERIC2) were examined to compare with RAPD as a means of fingerprinting organisms. The reproducibility was excellent. The results suggest RAPD primers can provide some useful comparative information on suspected related strains when tested on the same day and under the same conditions. PCR using REP1/REP2 and ERIC2 primers may provide a more reliable and reproducible alternative method for fingerprinting Gram negative bacteria.

DNA Fingerprinting↗
PubMed1995

Molecular method for typing Mycobacterium ulcerans.

A cluster of Mycobacterium ulcerans infections has recently occurred on Phillip Island, Victoria, Australia. Previous cases of infection have generally been located around Bairnsdale in southeast Gippsland. The aim of this study was to determine the epidemiological relationship between these strains and other strains originating in Australia and Africa. The previously described plasmid pTBN12 was used as a probe with restriction enzyme-digested chromosomal DNA to differentiate the strains of M. ulcerans. The probe was able to distinguish 11 restriction fragment length polymorphisms (RFLPs). Forty-three strains originating in Victoria were divided into three types, i.e., V1, V2, and V3. The majority of strains (40) yielded a type V1 pattern, including strains from southeast Gippsland. Fourteen strains from Queensland yielded three additional RFLP types, i.e., Q1, Q2, and Q3. Five strains from Benin and seven strains from Zaire yielded five additional RFLP types. It is envisaged that molecular typing of M. ulcerans strains from around the world may have a great impact on understanding of the epidemiology of infection with this organism.

Australia↗
PubMed1992

Prevalence of hepatitis C antibodies in patients with clotting disorders in Victoria. Relationship with other blood borne viruses and liver disease.

OBJECTIVE: To elucidate the seroepidemiology of hepatitis C in patients with clotting disorders in comparison with other blood borne infections; to examine the effects of hepatitis C on liver function; and to assess the effectiveness of current screening and inactivation procedures used in preventing the transmission of blood borne viruses by clotting factor preparations. DESIGN: A retrospective analysis of the prevalence of antibodies to hepatitis C virus (HCV), hepatitis B virus (HBV) and human immunodeficiency virus (HIV) by means of commercially available enzyme immunoassays (for antibodies to HCV and HIV) or radioimmunoassays (for HBV antibodies and surface antigen). An analysis was made of serum transaminase levels where such information was available and this was correlated with HCV status. PATIENTS AND SETTING: Panels of sera were collected from adults and children with clotting disorders attending two Melbourne haemophilia treatment centres in 1973 (n = 33), 1980 (n = 33), 1984-1985 (n = 111) and 1987-1990 (n = 217) and tested for antibodies to HCV, HBV and HIV. RESULTS: The prevalence of antibodies to HCV in the four panels tested was 45%, 74%, 75% and 76%, and the prevalence of markers of infection with HBV was 66%, 74%, 62% and 65% respectively. No antibodies to HIV were found in sera in Panels I and II but the prevalence in Panels III and IV was 23% and 36% respectively. In subjects in whom liver function test results were available, there was a significant association between the presence of antibodies to HCV and raised transaminase levels. Since heat inactivation of clotting factors was commenced in Australia in 1984, no new cases of transmission of HIV by clotting factors has been detected, but transmission of HCV in 19 subjects and HBV in one subject could not be excluded. CONCLUSIONS: Hepatitis C infection in haemophiliacs has been a very frequent event, and the presence of antibodies to HCV is associated with an increased incidence of raised transaminase levels. Screening and heat inactivation of clotting factors has prevented further HIV transmission, but exposure to HBV and HCV has not been eliminated.

Adolescent↗
PubMed1992

The development of hepatitis C antibody shortly after acute icteric non-A non-B hepatitis.

OBJECTIVE: To determine the relationship between the development of hepatitis C antibody (anti-HCV) and the clinical symptoms in acute hepatitis C. DESIGN: Retrospective analysis of sera from patients with acute non-A non-B hepatitis. SETTING AND PATIENTS: Patients admitted to Fairfield Hospital with the diagnosis of acute non-A non-B hepatitis between 1979 and 1989. Inclusion criteria included a typical clinical illness, accompanied by an alanine aminotransferase level of more than 2.5 times the upper limit of normal (normal, less than or equal to 40 U/L) and negative serological test results for acute hepatitis A and B. MAIN OUTCOME MEASURE: Time to develop anti-HCV after the onset of symptoms in patients with acute hepatitis C. RESULTS: Seroconversion was demonstrated in 26 of the 128 patients who fulfilled the inclusion criteria. In these patients, antibody was detected between one week and 32 weeks after the onset of dark urine; more than half the patients (54%) had seroconverted by four weeks and a third (34%) developed antibodies within two weeks. Of 20 patients who had sera collected within four weeks of the onset of dark urine, 14 (70%) had developed antibody. CONCLUSION: These results suggest that in patients with community-acquired hepatitis C, seroconversion occurs significantly earlier than is observed in patients who have been infected by blood transfusion. Sera taken shortly after the onset of symptomatic hepatitis C may be useful in the diagnosis of this condition.

Acute Disease↗
PubMed1991

Hepatitis C antibody testing: problems associated with non-specific binding.

The prevalence of antibodies to hepatitis C virus (anti-HCV) was measured in a number of groups known to be at increased risk of blood-borne viral infections, using an enzyme-linked immunosorbent assay (EIA) based on a nonstructural peptide generated by recombinant DNA technology. The assay was repeatably reactive in 75.6% of men with haemophilia, 61.9% of intravenous drug users, 34.1% of homosexual men who were regular attenders at a gay sauna and 30.8% of prisoners. A lower reactivity was detected in sera collected from female prostitutes (10.4%), patients undergoing maintenance haemodialysis (5.9%), or renal transplantation (6.9%) and patients attending a sexually transmitted diseases clinic (6.2%). We also measured reactivity among inmates of a large institution for the mentally handicapped in which hepatitis B is known to be endemic, and in panels of sera which had been stored for 25-35 years. The test was positive in 41.1% of mentally handicapped patients with Down's syndrome and 7% of subjects with other forms of mental retardation. Similarly some 23% and 20% of sera collected in 1954 and 1964 from patients with a variety of illnesses were found to be reactive. As most diagnostic assays suffer from some degree of non-specificity and confirmatory tests for the anti-HCV assay were not initially available in Australia, we analysed the distribution of optical density (OD) values in the different groups, in an attempt to obtain an insight into the specificity of the results being obtained. Whereas the ODs of sera collected from patients with haemophilia and IVDU had a bimodal pattern, with two well separated sets of results on either side of the cut-off.(ABSTRACT TRUNCATED AT 250 WORDS)

Antigens, Viral↗
PubMed1991

Comparison of immunofluorescence and culture for the detection of Actinomyces israelii in wearers of intra-uterine contraceptive devices.

A direct immunofluorescence (IF) method was compared with traditional culture methods for the detection of Actinomyces israelii in endocervical and intra-uterine-device (IUD) smears from 124 IUD wearers. Of 11 specimens that gave positive results by IF, only one was positive by culture. Of the 10 patients with positive IF specimens, three (30%) had signs and symptoms suggestive of pelvic infection and no other pathogen was detected. Direct IF of cervical smears offers a simple, relatively cheap method to screen IUD wearers for A. israelii. Clinical management of such cases is discussed.

Actinomyces↗
PubMed1991

T cell receptor and immunoglobulin gene rearrangement analysis as a laboratory aid in the diagnosis of human malignant lymphoproliferative diseases.

The identification of clonal rearrangements of the immunoglobulin heavy chain and T cell receptor beta chain gene loci by Southern blot analysis has led to advances in the diagnosis and classification of lymphoproliferative disorders. This paper reviews our experience with this technique over a three and a half year period. Specimens from 99 patients with suspected haematological malignancy were tested for leucocyte immunophenotype and immunoglobulin or T cell receptor gene rearrangement. Genotyping provided evidence of clonality in malignancies from 28 patients and demonstrated malignant cell lineage in eight patients not formally deduced from immunophenotyping alone. Our findings suggest that this technique can be employed in conjunction with immunophenotyping to aid in the determination of malignant cell lineage derivation and identification of malignant cell clonality, as well as potentially estimating the extent of disease, detecting relapse, and monitoring disease progression.

Gene Rearrangement↗
PubMed1990

Epidemiology and hepatitis C virus in Victoria.

Parenterally transmitted non-A, non-B (NANB) hepatitis virus or hepatitis C virus is a common cause of both acute and chronic hepatitis. Using a recently developed enzyme-linked immunosorbent assay we looked at the prevalence of antibodies to hepatis C virus (anti-HCV) in a number of groups. People with haemophilia (75.6%) and intravenous drug users (61.9%) had the highest prevalence, while homosexual men attending a sauna (34.1%) and prisoners (30.8%) had a moderately high prevalence of anti-HCV. A lower prevalence of antibody was detected in female prostitutes (10.4%), institutionalised mentally retarded subjects (9.5%), homosexual men requesting human immunodeficiency virus (HIV) testing through their local doctor (8.8%), dialysis patients (5.9%), renal transplant patients (6.9%), and patients referred from a sexually transmitted diseases clinic (6.2%). The lowest prevalence of anti-HCV was recorded in women attending a provincial hospital for antenatal care (0.4%). The predominance of anti-HCV in groups of people exposed to blood-borne and sexually transmitted infections suggests that these routes may be primarily involved in the spread of hepatitis C virus infection.

Adult↗
PubMed1990

Humoral immune responses in mice using gamma inulin preparations as adjuvants for hepatitis B vaccines.

There is an urgent need for new, powerful adjuvants suitable for use with sub-unit and peptide vaccines in humans. We have measured the humoral immune response in BALB/c mice to vaccine formulations using recombinant HBsAg antigens, and gamma inulin and alum adjuvants. Using Merck, Sharpe & Dohme (MSD) HBsAg at 10 micrograms/mL, high levels of anti-HBs were generated and geometric mean S/N ratios of 88, 133 and 107 were obtained for alum absorbed vaccine, gamma inulin, and a mixture of the two adjuvants, respectively. A dilution series produced ED50 values of 0.08, 0.15 and 0.22 micrograms/mL respectively. In a second series of experiments comparing alum and algamulin (a complex of gamma inulin and alum), MSD HBsAg induced anti-HBs levels of 81 and 52, and ED50 values of 0.3 and 0.4 when used in conjunction with alum and algamulin, respectively. SKF HBsAg induced anti-HBs levels of 126 and 111 with alum and algamulin, and ED50 values of 0.11 and 0.075. The class, subclass and level of antibody produced in mice boosted with a second dose of vaccine at 21 days was also examined. Both alum and gamma inulin induced higher levels of total antibody, IgG1 and minor IgG subclasses than algamulin, or HBsAg alone. Overall, gamma inulin appears to be an equivalent adjuvant to alum, although their mechanisms of action are different. Mixtures or complexes of the two adjuvants appear to be less effective in inducing humoral immune responses in mice than either alone.

Adjuvants, Immunologic↗