Biomedical subjects

M J Harding

Publications and source records attributed to M J Harding.

At least 19 recordsLinked to original sources

PubMed2001

Duration of immunity in cats after vaccination or naturally acquired infection.

The necessity for cats to be vaccinated annually against common pathogens has been questioned because sarcomas have infrequently been reported at the injection site. However, with few exceptions, the duration of immunity induced by vaccination or infection is uncertain, and there may therefore be a risk associated with a decision not to revaccinate. This article reviews the information available about the duration of immunity induced by vaccination or infection in cats, and reveals many shortcomings that make blanket recommendations impossible. Each vaccine must be considered individually.

Animals↗

PubMed2001

Duration of immunity in dogs after vaccination or naturally acquired infection.

This paper reviews current scientific information about the duration of immunity induced in dogs by infection or vaccination. It describes the shortcomings of the methods used to measure the immune responses of dogs, and explains the need for basic studies on the nature of protective humoral and cellular responses, and standardised assays for the long-term duration of immunity to pathogens other than rabies. The information is inadequate to warrant uniform recommendations on the ideal intervals for vaccination; each vaccine must be evaluated on the basis of its own merits and the characteristics of the disease it is intended to guard against.

Animals↗

PubMed2000

A field evaluation of international monitoring guidelines for the biological effects of tributyltin.

The Oslo and Paris Commission (OSPAR) Guidelines for monitoring the biological effects of tributyltin compounds (TBT) were evaluated using data collected for preparation of a Celtic Seas Quality Status Report. Two types of survey were undertaken: broad scale, to determine wide impacts in coastal waters; and localised, around representative harbours to establish ranges of effect from recognised input points. This evaluation indicates that results from the broad scale surveys can be used to compare different areas of coastline. Nucella is widespread away from point sources although many individuals show some degree of imposex. Populations are generally not at risk. The localised surveys indicate that, in certain situations, the monitoring objectives can be met in the OSPAR Guidelines (subject to minor amendment). Criteria are identified for the selection of point sources suitable for monitoring under OSPAR Guidelines.

Data Collection↗

PubMed1999

QUASIMEME laboratory performance study of the biological effects of tributyltin (imposex and intersex) on two marine gastropod molluscs.

The disruption of the endocrine systems of gastropod molluscs and consequential physiological changes (imposex and intersex) are used as biomarkers for environmental contamination by tributyltin compounds. The first international laboratory performance study on the determination of imposex and intersex in neogastropod molluscs, Nucella lapillus and Littorina littorea has been undertaken by the QUASIMEME (Quality Assurance of Information for Marine Environmental Monitoring in Europe) project. Samples of live gastropods were distributed and participants were asked to record shell height and sex, together with penis length and vas deferens sequence stage (VDS) in Nucella or the intersex stage (IS) and prostate length in Littorina. Calculations were made of vas deferens sequence index (VDSI) and the relative penis size index (RPSI) in Nucella and of intersex stage index (ISI) and the average female prostate length (FPrL) in Littorina. Thirteen (87%) of the 15 participating laboratories returned data. The remaining two laboratories asked to participate in later exercises. For Nucella, seven laboratories reported sex ratios significantly different from the reference laboratory data. Differences in penis length measurements between laboratories were largely random, although there were indications of systematic errors affecting the data from three laboratories. Seven laboratories reported satisfactory data (Z-score magnitude of Z < 2) for VDSI. The inclusion of a high proportion of sub-adults in the Nucella samples may have made separation of the sexes more difficult than in mature adults. The sub-adults will have had smaller pene than mature adults in the same population, and therefore any errors (random or systematic) in the measurement of penis length or observation of reproductive organs would have a potentially greater impact on the final reported values of the summary imposex indices. The Littorina sample did not show a high degree of intersex (ISI = 0.41). The laboratories could determine the sex of Littorina reliably and only one laboratory reported data significantly different from the reference laboratory. All except two laboratories reported satisfactory data for ISI.

Animals↗

PubMed1997

Specificity and nucleotyping studies of a gp50-based polymerase chain reaction assay for detection of pseudorabies virus.

PCR primers that amplify a region of the gp50 envelope glycoprotein gene of a number of vaccinal and field strains of pseudorabies virus (PRV) have been previously described (Galeota-Wheeler and Osorio, Am J Vet Res 1991: 52; 1799-1803). This gp50-based PCR assay was tested for its diagnostic applicability, utilizing a panel of nine PRV isolates and 13 related herpesviruses, originating from domestic animal species and man. Slight modifications to the original PRV PCR protocol ensured that false positive PCR products from avian herpesviruses were not evident in agarose gel electrophoresis analysis. Nucleotide sequence data derived from the PCR product revealed that the region of the genome amplified was markedly conserved and allowed only for virus subgrouping, rather than definitive isolate characterization.

Animals↗

PubMed1997

A preliminary study to examine the adequacy of long-term treatment of depression and the extent of recovery in general practice.

About 1% of patients in general practice take antidepressants for long periods. Many receive repeat prescriptions, without review. It might be assumed that these patients are well and are on adequate maintenance treatment. Our findings refute this assumption; of 78 patients on long-term repeats, only a third were in remission and a fifth had Beck Depression Inventory scores suggesting persisting syndromal major depression. Subtherapeutic dosing of classic tricyclics was the norm rather than the exception. Patients on long term antidepressant treatment need regular review and adequate treatment to ensure remission is maintained.

Adult↗

PubMed1997

Production of a baculovirus-derived gp50 protein and utilization in a competitive enzyme-linked immunosorbent assay for the serodiagnosis of pseudorabies virus.

The pseudorabies virus (PRV) gp50 envelope glycoprotein gene was cloned and expressed in a recombinant baculovirus. An anti-gp50 Mab (1842) recognized a protein of approximately 40 kDa in immunoblotting assays from infected insect cell lysates, while this product was not present in cells infected with wild-type baculovirus. The recombinant protein was purified by lectin affinity chromatography, utilizing lectins specific for O-linked oligosaccharides (Artocarpus integrifolia and Glycine max). Competitive (c) ELISAs, using either crude or lectin-purified antigen, were devised for the detection of antibodies to PRV in sera, and were capable of monitoring sero-conversion by day 14 post-infection. Furthermore, a specificity of 100% and sensitivity of 98% (crude lysate antigen) or 96% (lectin-purified antigen) was found for a panel of 80 swine sera, using the cELISA, as compared to a serum neutralization (SN) test. These studies demonstrated that recombinant PRV gp50 protein shows promise as a cELISA antigen, for serodetection of PRV.

Animals↗

PubMed1996

Evaluation of nucleic acid amplification methods for the detection of hog cholera virus.

A blind panel was tested in a diagnostic evaluation of a reverse transcription (RT) polymerase chain reaction (PCR) method for detecting hog cholera virus (HCV) from pig tissues. The capability of the RT-PCR test to discriminate between HCV and related pestiviruses, bovine viral diarrhea virus (BVDV), and those viruses causing similar diseases in swine, including African swine fever virus (ASFV) and pseudorabies virus (PRV), was also considered. Nucleic acid extraction involved either kit-based or conventional phenol:chloroform:isoamyl alcohol methods. A single-round PCR assay, using primers that hybridize to the conserved p120 nonstructural gene region, was 82.5% sensitive (n = 17) and 100% specific (n = 18) in the detection of the presence of HCV RNA. However, the sensitivity was increased to 100% following a second PCR test. In all, 4 HCV, 7 BVDV, 2 ASFV, and 1 PRV isolates were studied. Novel nucleic acid sequences were generated for 9 HCV strains. Analysis of a portion of the p120 region using these methods was suitable for HCV isolate characterization.

African Swine Fever Virus↗

PubMed1996

Development of PCR-based tests for the identification of North American isolates of epizootic haemorrhagic disease virus.

A serogroup-specific polymerase chain reaction (PCR) assay and isolate identification strategies (restriction endonuclease analysis (REA) and nucleotide sequencing) were developed for the detection of North American isolates of epizootic haemorrhagic disease virus (EHDV). PCR primers (EHDV-pr4, EHDV-pr5) were designed to hybridize to the L3 gene of a North American isolate of EHDV serotype 1. Total nucleic acid was extracted from preparations of infected tissue culture and PCR was performed using a cDNA-PCR kit, according to the manufacturer's specifications. The PCR assay generated a 459 base pair product from North American isolates of EHDV serotypes 1 and 2, while bluetongue virus (BTV) serotypes 10, 11, 13, and 17, and cell controls, failed to demonstrate PCR products. Slight modifications allowed for the PCR detection of EHDV-1 and -2 in white-tailed deer blood (Odocoileus virginiatus); PCR fragments were not amplified from uninfected deer blood. A number of restriction endonucleases and sequencing primers were evaluated for their utility in isolate identification experiments. Specifically, REA employing HincII and cycle sequencing with an internal primer (EHDV-1-pr3) proved most successful for identifying isolate-specific genome markers. The techniques presented are expected to prove valuable for rapid and specific detection of possible future EHDV incursions in wild and domestic animal species.

Animals↗

PubMed1995

Tuberculosis epidemiology in Croydon.

A survey of tuberculosis in Croydon between 1988 and 1991, using Chest Clinic health visitor records, showed that the disease occurred most frequently in those of Indian Sub-Continent (ISC) ethnic origin. Of the 222 cases during the 4-year period, 65% were of ISC ethnic origin, 22% were Caucasian and 11% Afro-Caribbean. Non-Caucasian cases were younger (P < 0.0001), and more likely to be female (P = 0.064) or present with non-pulmonary disease (P = 0.064). One-quarter of ISC patients developed active tuberculosis more than 15 years after immigration into the UK. Only seven cases were children. The contact tracing procedure resulted in three additional cases, all of whom were contacts of smear-positive index cases. There were significantly fewer Heaf or radiologically positive contacts of non-smear positive pulmonary, or non-pulmonary index cases (P = 0.0002). The value of the current contact tracing system is discussed.

Adolescent↗

PubMed1995

Identification of the major North American bluetongue viruses using nucleic acid amplification techniques.

A set of primers (BTV-pr1/2) were selected that hybridized to the VP3 gene of the major North American serotypes of bluetongue virus (BTV). Polymerase chain reaction (PCR) testing yielded positive results from specimens of major North American BTV isolates (serotypes 10, 11, 13 and 17) propagated in Vero cells. In addition, PCR assays were positive from samples of all other BTV serotypes, except BTV-16; however, an alternative primer pair (BTV-prN1/N2) was devised for amplification of this serotype and the major North American BTV serotypes. PCR products were not evident following amplification of related viruses, epizootic haemorrhagic disease virus (EHDV) serotypes 1 or 2, in either PCR test. In addition, slight modification of the nucleic acid extraction method allowed for the amplification of BTV template from ovine and cervine blood, but not from the respective control blood samples. Restriction endonuclease analysis (REA) using AluI and TaqI discriminated the PCR products of BTV serotypes 10, 13 and 11/17. Identification of BTV-11 and -17 was accomplished by PCR product nucleotide sequencing. Thus, using a single gene region (VP3), nucleic acid amplification methods were devised for expeditious serogroup-specific detection of all BTV serotypes and identification of individual North American BTV nucleotypes, which is expected to prove valuable for disease control strategies and retrospective epidemiological analyses.

Base Sequence↗

PubMed1994

Use of polymerase chain reaction to detect porcine parvovirus associated with swine embryos.

The role of porcine parvovirus (PPV) in inducing reproductive failure in swine has been extensively documented. However, information is not available as to the risk of PPV transmission by embryo transfer. Using the polymerase chain reaction (PCR) technique, PPV-specific DNA was detected in association with 4-day-old porcine embryos incubated in vitro in the presence of NADL-8 strain of PPV, despite attempts to rid the embryos of virus by either washing or treatment with pronase or trypsin. The presence of PPV in embryos collected from acutely infected swine was not detected by PCR, although PPV DNA was detected in the proximal portion of the reproductive tract during the early stages of infection. Viral-specific nucleic acid was not detected in embryos transferred from infected donors to seronegative recipients and retrieved and assayed on the 15th and 32nd days of gestation. Results of the use of PCR to detect PPV associated with swine female reproductive tract and embryos ascribe minimal risk to the transmission of PPV to seronegative recipients through embryo transfer.

Abortion, Veterinary↗

PubMed1993

Management of malignant teratoma: does referral to a specialist unit matter?

The causes of geographical differences in cancer survival among regions of the UK are unclear. Population-based audit of management of patients with non-seminomatous germ-cell tumours (NSGCT) in the west of Scotland enabled us to assess the relative contributions to outcome of recognised prognostic factors, treatment centre, and protocol treatment. Data on treatment and outcome were analysed for 440 (97%) of 454 men with NSGCT diagnosed between 1975 and 1989. All but 11 patients were treated at tertiary referral centres; 235 were treated at a single unit (unit 1) and 194 at four other units (2-5). 99 men have died, 89 (20%) from NSGCT. Independent prognostic factors for NSGCT survival were extent of tumour at diagnosis (p < 0.001), 5-year period of diagnosis (from 1975-79 to 1985-89, p < 0.001), and treatment unit (unit 1 vs units 2-5, p < 0.001). Unit 1, which had the best survival rates, treated most patients overall (53%), including the majority (70%) in the worst prognostic category (poor-prognosis metastatic disease). The proportion of men receiving nationally agreed protocol treatment was higher at unit 1 than elsewhere (97 vs 61%, p < 0.0001). However, analysis restricted to men who received protocol treatment, adjusted for other important prognostic variables, still showed a survival advantage for this unit (relative death rate units 2-5 vs unit 1, 2.82 [95% CI 1.53-5.19], p < 0.001). These findings suggest that centralisation of treatment for NSGCT improves outcome; the benefit seems to be additional to any advantage resulting from protocol treatment.

Adult↗

PubMed1992

A monoclonal antibody which recognizes cell surface antigen and inhibits porcine parvovirus replication.

Monoclonal antibody technologies were applied to the study of early events in porcine parvovirus (PPV) infections in vitro. Balb/c mice were immunized with whole swine testicle cells and hybridomas were produced following fusion with myeloma cells. Resultant clones were screened firstly in an ELISA system, to detect monoclonal antibody recognition of swine testicle cells, and secondly, in a fluorescent antibody test to detect monoclonal antibody which inhibited production of PPV antigen. One clone, 1H11, which satisfied these screening requirements, recognized proteins present in cell lines both permissive and non-permissive for porcine parvovirus replication and inhibited the production of virus progeny of several PPV isolates. A linear staining pattern of cross-linked plasma membranes, indicative of monoclonal antibody binding at the cell membrane, was demonstrated by indirect immunofluorescence assays. In immunoblotting experiments, 1H11 recognized a polypeptide of approximately 40 kDa in size, present in both permissive and non-permissive cell lines.

Animals↗

PubMed1991

Mechlorethamine, vinblastine, procarbazine and prednisolone (MVPP) for advanced Hodgkin's disease.

Between January 1972 and October 1985, 60 patients with advanced Hodgkin's disease were treated with mechlorethamine/vinblastine/procarbazine/prednisolone (MVPP). The complete remission (CR) rate was 50%; the introduction of computed tomography in 1980 reduced the proportion of CR from 62% to 30% (P = 0.017) as a consequence of residual mediastinal abnormality of uncertain significance. With a median follow-up of 9 years, actuarial 5 and 10-year overall survival was 70% and 57%, respectively, with 79% and 65% free from Hodgkin's disease. Only age and pathological subtype influenced survival sufficiently to be of prognostic significance, though the effect of serum albumin, ECOG performance status and B symptoms on Hodgkin's disease mortality may have been clinically important.

Adolescent↗

PubMed1991

BOP/VIP--a new platinum-intensive chemotherapy regimen for poor prognosis germ cell tumours.

Ninety-one patients with poor prognosis non-seminomatous germ cell tumours (NSGCT) were treated with an initial intensive chemotherapy schedule. Suitable patients fulfilled one or more of the following criteria: lymph node metastases greater than 10 cm diameter; liver, brain or bone metastases; serum HCG level greater than 50,000 IU/L; and extragonadal primary tumours. Treatment consisted of 3 cycles of bleomycin, vincristine and cisplatin (BOP) administered at 10 day intervals, followed by 3 cycles of etoposide, ifosfamide and cisplatin (VIP) at 21 day intervals. A total of 64 patients (70%) achieved a complete remission. This comprised 46 patients who received BOP/VIP only, and 18 patients who received additional chemotherapy after BOP/VIP. Of these 64 patients, 51 underwent complete surgical resection of residual masses, including 11 in whom there was evidence of teratoma with cellular atypia or non-germ cell cancer in the resected tissue. A further 9 patients had persisting unresected radiological masses in the presence of marker complete remission. The overall response rate was 80%. Currently 57 patients (63%) remain alive and free from disease progression. The median follow-up period is 90 weeks (range 24-206 weeks), with a 2 yr actuarial progression-free survival of 66% (95% c.i. 55-77%). Major toxicity was myelosuppression, occurring during the VIP arm of therapy, with a median nadir WBC of 1.1 x 10(9)/L and median platelet count of 51 x 10(9)/L. Other toxicity included peripheral neuropathy (WHO Grade 2 and 3 in 22%). We conclude that treatment results with the BOP/VIP schedule in this poor prognosis patient group are at least comparable with other schedules, and toxicity is manageable.(ABSTRACT TRUNCATED AT 250 WORDS)

Antineoplastic Combined Chemotherapy Protocols↗

PubMed1989

Excision of residual masses after platinum based chemotherapy for non-seminomatous germ cell tumours.

Between January 1980 and June 1987, 42 patients receiving platinum based combination chemotherapy for advanced non-seminomatous germ cell tumours had residual masses, detected by computed tomography, after four or six treatment courses without tumour marker evidence of active disease. Resection of retroperitoneal (n = 32), pulmonary (n = 4) or thoracoabdominal (n = 2) disease revealed residual malignancy in nine patients (21%), differentiated teratoma in 14 (33%) and fibrosis or necrosis in 15 (36%). Laparotomy showed no evidence of a mass in four instances. Of the 42 patients, 14 had malignant teratoma undifferentiated in the primary tumour only one of whom (7%) had evidence of malignancy in the specimen resected post-chemotherapy. Conversely, six of 15 patients (40%) whose primary tumour was malignant teratoma intermediate had residual malignant tissue after treatment. With a median follow up of 36 months from post-chemotherapy surgery, 36 patients (86%) are continuously disease-free. Relapses occurred in one of nine patients with residual malignancy (11%), three of 14 with differentiated teratoma (21%), one of 15 with necrosis or fibrosis (7%) and in one patient who had a normal laparotomy. Four patients have died from their tumours, but two are currently disease-free following further surgery and chemotherapy for relapse. Neither primary nor post-chemotherapy histology was predictive of relapse, and although relapse was numerically more common in patients whose residual mass was incompletely excised (three of 12), this was not statistically significant.

Adolescent↗

PubMed1988

Porcine parvovirus: replication in and inhibition of selected cellular functions of swine alveolar macrophages and peripheral blood lymphocytes.

The ability of four isolates of Porcine Parvovirus (NADL-8, NADL-2, KBSH, and Kresse) to replicate in and affect the functions of swine peripheral blood lymphocytes and alveolar macrophages was studied in vitro. V-strand and C-strand viral DNA was present in both concanavalin A- and non-treated lymphocytes as well as alveolar macrophages following infection with all four isolates. Indirect fluorescent antibody assays on swine testis cells, inoculated with cell lysates of NADL-8-infected peripheral blood lymphocytes (both concanavalin A- and non-treated) and alveolar macrophages, indicated that these immune cells supported the production of progeny virus. The quantity of viral DNA and progeny virus was dependent upon the multiplicity of infection and length of time following infection. Infection of lymphocytes and alveolar macrophages with PPV was associated with a decrease in cell viability. Peripheral blood mononuclear cells and alveolar macrophages infected with any of the four isolates demonstrated reduced lymphocyte blastogenesis and non-Fc-mediated alveolar macrophage phagocytosis, respectively.

Animals↗