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Biomedical subjects

M J Day

Publications and source records attributed to M J Day.

At least 127 records · Page 7Linked to original sources
PubMed1996

Expression of interleukin-1 beta, interleukin-6 and tumour necrosis factor alpha by macrophages in canine lymph nodes with mineral-associated lymphadenopathy, granulomatous lymphadenitis or reactive hyperplasia.

The distribution of CD3+ T lymphocytes and the expression of interleukin-1 beta (IL-1 beta), interleukin-6 (IL-6) and tumour necrosis factor alpha (TNF alpha) by macrophages in canine lymph nodes with mineral-associated lymph-adenopathy, granulomatous lymphadenitis or reactive hyperplasia was examined immunohistochemically. In areas of preserved lymph node architecture, CD3+ T lymphocytes were located in the paracortex, with scattered cells in the follicular mantle and germinal centre, and small aggregates in the medullary cords. T cells were prominent within areas of diffuse granulomatous inflammation and formed a peripheral rim around microgranulomas. TNF alpha expression was demonstrated in macrophages from seven of 11 dogs with mineral-associated lymphadenopathy, one of five dogs with granulomatous lymphadenitis and three of five with reactive hyperplasia. Positive macrophage staining for IL-1 beta and IL-6 was seen in two lymph nodes with reactive hyperplasia. Lymph nodes from control (clinically normal) dogs showed no evidence of cytokine expression. Neutrophils expressing IL-1 beta were observed within the medullary sinuses of two lymph nodes with mineral-associated lymphadenopathy and one with reactive hyperplasia, and in the inflammatory infiltrate in one lymph node with granulomatous lymph-adenitis. The sensitivity of immunohistochemical examination as a means of detecting cytokines in abnormal tissue is discussed.

Animals↗
PubMed1996

Expression of major histocompatibility complex class II molecules by dermal inflammatory cells, epidermal Langerhans cells and keratinocytes in canine dermatological disease.

The distribution of Major Histocompatibility Complex (MHC) Class II molecules in skin biopsies from 42 dogs with primary skin disease and six control dogs was examined by indirect immunohistochemical methods. Canine epidermal Langerhans cells constitutively expressed MHC Class II and the number of such cells was increased in the epidermis of dogs with discoid lupus erythematosus (n = 10), hypersensitivity dermatitis (n = 10) or deep pyoderma (n = 13) but not in eight cases of pemphigus foliaceus. Expression of MHC Class II by epidermal and follicular keratinocytes was observed in a ninth dog with pemphigus foliaceus. Within dermal inflammatory infiltrates, Class II was expressed by macrophages, dendritic cells and fibroblasts but not by neutrophils, eosinophils, mast cells or plasma cells. Only occasional dermal lymphocytes expressed surface MHC Class II, but nodular aggregates of strongly Class II-positive lymphocytes were observed within the dermis of two dogs with discoid lupus erythematosus.

Animals↗
PubMed1996

IgG subclasses of canine anti-erythrocyte, antinuclear and anti-thyroglobulin autoantibodies.

A panel of monoclonal antibodies (mAbs) reactive with the four canine IgG subclasses (IgG1, IgG2, IgG3 and IgG4) was used to investigate the activity of IgG subclasses in autoimmune responses to erythrocytes, nuclear antigens and thyroglobulin in dogs with autoimmune disease. mAbs specific for canine IgG1 and IgG4 were able to agglutinate normal dog erythrocytes coated with purified canine IgG containing each of the four subclasses. IgG1 autoantibodies were demonstrated on the surface of erythrocytes from seven dogs with Coombs'-positive autoimmune haemolytic anaemia and IgG4 autoantibodies were also present in two of these cases. Serum antinuclear antibody was shown in nine dogs to be predominantly of IgG1, IgG3 and IgG4 subclasses with only one of the dogs also producing an IgG2 antinuclear antibody. The IgG subclass profile of antinuclear antibodies differed between dogs with polyarthritis and dogs with other systemic disease. In six dogs with hypothyroidism, thyroglobulin autoantibodies of subclasses, IgG1, IgG2 and IgG4 predominated, but one dog also produced significant levels of IgG3 thyroglobulin autoantibodies. The mAbs are widely applicable to the study of the pathogenesis of canine autoimmune disease.

Agglutination Tests↗
PubMed1996

Subclass profile of allergen-specific IgG antibodies in atopic dogs.

Levels of allergen-specific IgE and IgE antibodies were determined in serum samples from 60 atopic and 11 normal dogs by means of commercially available ELISA test kits and a panel of 33 allergens. In the atopic population, IgE antibodies were most commonly identified with a specificity for Dermatophagoides farinae (78.3 per cent of affected dogs), D pteronyssinus (61.6 per cent), mould mix (25 per cent) and house dust (19 per cent), whereas the most frequently detected IgG antibodies had a specificity for D farinae (38.3 per cent), D pteronyssinus (33.3 per cent), mould mix (33.3 per cent), insect mix (16.6 per cent) and meadow fescue (16.6 per cent). The IgG subclass profile of allergen-specific antibodies was determined for five representative allergens from the panel. The IgG response to D farinae and D pteronyssinus was dominated by IgG4 antibodies, although lower levels of IgG2, and IgG3 and IgG1 D pteronyssinus antibodies were also detected. The IgG response to Timothy grass was predominantly within the IgG1 and IgG4 subclasses, IgG subclass selection in the response to mould mix and insect mix was broader, with relatively low level reactions from all four subclasses. The data suggest a degree of IgG subclass restriction in the humoral immune response of canine atopy which may be dependent upon the nature of the allergen.

Allergens↗
PubMed1996

Inheritance of serum autoantibody, reduced serum IgA and autoimmune disease in a canine breeding colony.

Immunological parameters were examined in 113 English cocker spaniel dogs from two breeding kennels. Dogs from kennel 1 (n = 86) were grouped as having idiopathic cardiomyopathy (n = 19), autoimmune or other disease (n = 7) or being clinically normal (n = 60). Dogs from kennel 2 (n = 27) were all clinically normal and used for comparative purposes. There was a high incidence of serum antinuclear antibody (ANA) amongst all groups from kennel 1 (39/82 dogs tested), with anti-thyroglobulin and anti-erythrocyte antibodies also recorded in a dog with systemic lupus erythematosus. Thirty percent of dogs with idiopathic cardiomyopathy had anti-mitochondrial antibody. Thirteen dogs from kennel 1 had reduced serum IgA (< or = 0.3 mg/ml), but there was no consistent abnormality in the concentration of serum IgG, IgM, complement C3 or C4 in these thirteen dogs, or other dogs from this kennel. No immunological abnormality was recorded in dogs from kennel 2. Pedigree analysis of dogs from kennel 1 revealed inheritance of autoimmune disease, serum ANA and low serum IgA within several breeding lines. Inheritance of idiopathic cardiomyopathy was recorded through three generations and a strong association demonstrated between the presence of this disorder and a particular complement C4 phenotype (C4: 4).

Animals↗
PubMed1996

Damage to Pseudomonas aeruginosa PAO1 bacteriophage F116 DNA by biocides.

The mechanism of action of biocides against viruses has not been widely studied, although two main targets are viral proteins (capsids, enzymes) and the viral genome. This study was undertaken in order to investigate the efficacy of several disinfectants against the nucleic acid of the Pseudomonas aeruginosa PAO bacteriophage F116. Of all the biocides tested, only peracetic acid affected significantly the phage genome. However, it is not clear whether the nucleic acid was damaged inside the phage capsid or when released into the surrounding medium.

1-Propanol↗
PubMed1996

The use of an automated assay to assess phage survival after a biocidal treatment.

The coliphage K1-5 has been used in an automated assay to monitor the viricidal activity of various disinfectants. This indirect assay based on the spectrophotometric reading of the lysis of the host cell (Escherichia coli D837) produced encouraging results and was faster than the overlay counting method (previously studied) which relies on plaque formation. However, differences in sensitivity towards some disinfectants were observed between the two methods.

1-Propanol↗
PubMed1996

Serial monitoring of clinical, haematological and immunological parameters in canine autoimmune haemolytic anaemia.

Clinical, haematological and immunological data are presented from 14 dogs with autoimmune haemolytic anaemia (AIHA) serially monitored for up to 945 days after initial presentation. At the time of diagnosis, all dogs had severe anaemia (mean packed cell volume [PCV] 17.6 +/- 7.1 per cent) with leucocytosis in seven cases and thrombocytopenia in four dogs. The Coombs' test was positive in all cases. Immunoglobulin G (IgG) autoantibody alone was identified in eight cases, a combination of IgG and IgM autoantibodies was recognised in three cases, and in two dogs only IgM autoantibody was recorded (complement fixing in one of these dogs). All dogs were treated with immunosuppressive doses of corticosteroids and some animals also received cyclophosphamide (four cases), azathioprine (two cases), blood transfusion (four cases) or underwent splenectomy (two cases). Two dogs died during the initial episode of AIHA. In 12 dogs, the anaemia was resolved by an average of 36.3 +/- 16.0 days after initial presentation, but autoantibody titre often persisted after clinical improvement and normalisation of PCV. Four dogs had a clinical relapse 67 to 170 days after initial presentation and one of these dogs subsequently died from thromboembolic disease. One dog developed lymphocytic thyroiditis and serum antinuclear antibody at day 691 after initial presentation, and two cases developed disease consistent with autoimmune thrombocytopenia (AITP) at 365 and 618 days post initial presentation. In one of these dogs, AITP was concurrent with multicentric lymphoma. No correlation was recorded between haematological and immunological parameters at presentation and subsequent response to therapy or long-term clinical behaviour.

Adrenal Cortex Hormones↗
PubMed1996

Renal amyloidosis in related English foxhounds.

Renal amyloidosis was diagnosed in six related English foxhounds from two separate hunting kennels. There was no apparent age or sex predilection. All the dogs had clinical and laboratory findings compatible with renal disease. The onset of clinical signs was acute in all cases with death or euthanasia in five of the six affected dogs occurring within one week of presentation. The remaining dog was treated with diuresis which produced a temporary improvement. Histological examination of renal tissue from affected dogs identified the presence of both glomerular and interstitial amyloid, which was confirmed by immunohistochemical staining to be of the reactive type (amyloid A). There were occasional sclerosed glomeruli or glomeruli with thickened Bowman's capsules, in addition to interstitial and periglomerular infiltration with a predominance of plasma cells and lymphocytes and secondary changes including tubular eosinophilic casts. Renal papillary necrosis was identified in three dogs. One hound had concurrent multicentric lymphoma. Pedigree analysis of the affected dogs revealed that four individuals shared a common great grandsire and that the same dog was the grandsire of a further case. Pedigree analysis of five additional dogs from one of the kennels, all of which had clinical signs of acute renal failure but from which renal tissue was not available, revealed a close relationship to those foxhounds with confirmed renal amyloidosis.

Amyloid↗
PubMed1996

Natural transformation in river epilithon.

Natural transformation was demonstrated in unenclosed experiments incubated in river epilithon. Strains of Acinetobacter calcoaceticus were transformed to prototrophy by either free DNA (lysates) or live donor cells. The sources of transforming DNA and recipient culture were immobilized on filters, secured to stones, and incubated midstream in the river. The transfer frequency generally increased with temperature. No transfer was detected in the river Taff below 10 degrees C. The age of the recipient culture affected the transformation frequencies in situ but did not significantly affect the transfer frequency on laboratory media. Transformation of recipient cultures which had been incorporated into the natural epilithic biofilm and transformation of the plasmid pQM17 in situ were also demonstrated. This study provides the first direct evidence of natural transformation in situ of bacteria incorporated into an indigenous community.

Acinetobacter calcoaceticus↗
PubMed1996

Lesions associated with mineral deposition in the lymph node and lung of the dog.

This report includes details of the clinical and pathologic features of 31 dogs with a range of systemic illness and granulomatous lymphadenopathy associated with the presence of birefringent crystalline material within lymph nodes. Similar crystalline material was found in the lymph nodes of dogs with lymphoma (n = 9) and as an incidental finding within the canine lung (n = 9). The mineral content of these crystals was determined by electron microprobe analysis and interpreted in light of the composition of known geological or human-made compounds. A wide range of elements was identified including silicon, sulfur, copper, calcium, and aluminium, with lesser proportions of phosphorus, sodium, potassium, iron, magnesium, titanium, nickel, and chromium. Many of these compounds may have originated from exogenous natural and human-made sources, but some compounds (notably phosphates and sulfates) are uncommon or not found in nature and may have been formed within the tissues of the body (biomineralization). The inflammatory response induced by the presence of these minerals within lymphoid tissue may trigger altered immunoregulation, accounting for the spectrum of disease observed.

Aluminum↗
PubMed1996

Quantitation of erythrocyte-bound IgG subclass autoantibodies in murine autoimmune haemolytic anaemia.

A quantitative and sensitive cellular enzyme-linked immunosorbent assay was developed for determining the number of molecules of IgG of each subclass bound to the surface of murine red blood cells (RBC). To develop standard titration curves, RBC from normal mice were treated with tannic acid and coated with a known concentration of purified myeloma of each IgG subclass. The quantity of each subclass bound to the surface of erythrocytes was determined by calculating the protein concentration of the bound IgG, which was then converted into number of molecules of IgG/RBC. The assay was used to quantify the number of autoantibodies of all four IgG subclass bound to the erythrocytes of mice injected with rat RBC. Twenty one days after the first immunisation, a mean number of 84,000 molecules of IgG1/RBC were detected, which increased to 114,500 molecules/RBC on day 28. On days 56 and 96 the mean concentration of IgG1 remained high, however by day 110 the mean level of IgG1 had decreased slighty to 69,500 molecules/RBC. By contrast, the mean concentration of IgG2a autoantibodies was considerably lower throughout the experiment, starting at 40,200 molecules/RBC on day 21 and dropping to 2,500 molecules/RBC by day 110. The mean quantities of IgG2b and IgG3 autoantibodies were similar to each other, and intermediate between the levels of IgG1 and IgG2a autoantibodies.

Anemia, Hemolytic, Autoimmune↗
PubMed1996

Antibiotic and biocide resistance in bacteria.

Antibiotic-resistant bacteria pose an ever-increasing therapeutic problem. The ways whereby bacteria circumvent drug action are many and varied, ranging from intrinsic impermeability to acquired resistance (involving plasmids, transposons and mutations). Antibiotics may be unable to reach susceptible target sites, they may be enzymatically inactivated, modified or expelled or mutations may arise such as to render the target sites insusceptible. Mechanisms of bacterial resistance to biocides are less well understood but cellular impermeability is a major factor. Plasmid-mediated efflux of cationic antiseptics in antibiotic-resistant Staphylococcus aureus strains has been demonstrated but its role in the resistance of these organisms to the biocide concentrations used in clinical practice is unclear. An association between resistance to antibiotics and biocides in Gram-negative bacteria has also been observed but it is often difficult at present to reach definite conclusions about genetic linkages between antibiotic resistance and biocide resistance.

Anti-Bacterial Agents↗