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D A Higgins

Publications and source records attributed to D A Higgins.

At least 37 records · Page 2Linked to original sources
PubMed1990

Yolk-sac transmission and post-hatching ontogeny of serum immunoglobulins in the duck (Anas platyrhynchos).

1. To investigate the immunoglobulin (Ig) class which is active in yolk-sac transmission of maternal antibodies in ducks, sera from laying ducks, yolks from their eggs, and sera from ducklings 0-87 days of age were examined by immunoelectrophoresis (IE), and Na2SO4-precipitated Igs from these sera and yolks were run in polyacrylamide gel electrophoresis (PAGE) under reducing conditions. 2. In yolk, 7.8S IgG was greatly enriched compared to 5.7S IgG and IgM, and was the only Ig to reach the sera of newly hatched ducklings. 3. The levels of maternally derived 7.8S IgG in duckling sera decreased after 5 days of age, reaching minimum levels at about 14 days of age. 4. Increases in the serum levels of 7.8S IgG, 5.7S IgG and IgM occurred after 20 days of age, reflecting de novo synthesis by the duckling, and the adult serum profile was achieved by 71 days of age. 5. The involvement of 7.8S rather than 5.7S IgG in yolk-sac transmission was probably determined by the additional heavy chain components of this molecule.

Animals↗
PubMed1989

Precipitating antibodies of the duck (Anas platyrhynchos).

1. Ducks do not usually produce precipitating antibodies. However, when hyperimmunized with the dinitrophenyl (DNP)-human IgG (HIgG) conjugate, ducks made precipitating antibodies to the HIgG carrier, though not to the DNP hapten. 2. Precipitation did not require NaCl and occurred over a wide range of molarities and pH. 3. Antigenic and polyacrylamide gel analysis of affinity-purified antibodies, indicated that the major constituent of the antibody population was electrophoretically homogeneous 5.7S IgG. 4. The Ig heavy chains were in two populations, viz MW 37,000 and 41,000; non-precipitating duck 5.7S IgG antibodies to HIgG had only the MW 37,000 heavy chains. 5. It is suggested that duck precipitins belong to a previously unrecognized subclass of duck 5.7S IgG, with minor physical and antigenic differences from their non-precipitating counterparts.

Animals↗
PubMed1988

Duck lymphocytes. II. Culture conditions for optimum transformation response to phytohaemagglutinin.

The lymphocyte transformation (LT) test was performed with duck blood lymphocytes in 96-well microtitre trays against nine concentrations (0.1-100 micrograms/ml) of phytohaemagglutinin (PHA). It was found that incubation at 41.6 degrees C (duck body temperature) gave better results than incubation at 37 degrees C, and that a 6 h pulse with [3H]thymidine gave better results than an 18 h pulse. Cell concentration was very critical: successful duck LT required rather high concentrations of cells (approximately 4 X 10(6)/ml, equivalent to approximately 8 X 10(5)/culture) while lower and higher concentrations gave inferior results. Duck serum supported LT optimally when used at a concentration of 10-15%, but a serum pool from adult (approximately 6-month-old) ducks gave superior results to sera from younger birds. Foetal calf serum supported duck LT strongly when used at 20%, but only poorly at 10%, while chicken serum supported duck LT when used at 5-20%. Ultroser G was an ineffective supplement, and the addition of 5% tryptose phosphate broth to other supplements had variable effects. Using optimum culture conditions, maximum LT responses were obtained after 2-3 days' culture, when it was possible to obtain stimulation indices of 500-5000. The addition of PHA to cultures could be delayed for up to 18 h without affecting LT, but thereafter the cells rapidly lost responsiveness.

Animals↗
PubMed1988

HLA typing in the Hong Kong Chest Service/British Medical Research Council study of factors associated with the breakdown to active tuberculosis of inactive pulmonary lesions.

As part of a multifactorial study of the causes of breakdown to active tuberculosis of inactive pulmonary lesions, HLA-A, -B, and -DR typing was performed on 256 Hong Kong Chinese patients and 100 healthy control subjects. Patients were classified into those with smear-positive, active pulmonary tuberculosis (n = 103), those with inactive disease (n = 113), and those with breakdown to active disease after 6 months or more of inactivity (n = 40). Separately, 21 multiple-case families comprising 38 available parents and 93 offspring were examined for HLA haplotype segregation in relation to infection. Results of both studies indicate that among Hong Kong Chinese there is no statistically significant association between HLA and susceptibility to pulmonary tuberculosis.

Adolescent↗
PubMed1987

Bile immunoglobulin of the duck (Anas platyrhynchos). II. Antibody response in influenza A virus infections.

The capacity of the IgM-like bile immunoglobulin (IgX) of the duck (Anas platyrhynchos) to express antibody activity to H3N2 influenza A viruses, and the dependence of this activity on the co-existence of serum IgM antibodies were investigated. Ducklings infected orally and intranasally at 15-29 days of age with viruses isolated from different host species were examined for haemagglutination-inhibiting (HI) antibodies in biles and sera 16-29 days after infection (p.i.). All biles had antibodies associated with IgX; all sera had antibodies associated only with the 7.8S IgG. Following oral infection of birds 42-days-old with influenza A/duck/HK/7/75 virus, serum HI antibodies were an initial IgM response occurring from 5-12 days p.i., followed by the appearance of 7.8S IgG antibodies. Virus-neutralizing (VN) antibodies in serum were also biphasic; isotype classification was not attempted. Bile IgX developed HI and VN activity. HI antibodies reached peak titres 12 days p.i. and fell to low levels by 24 days p.i. VN antibodies also reached peak titres 12 days p.i., but thereafter persisted at quite high levels throughout the experiment. Development of high titres of antibody in bile coincided with the termination of virus excretion in faeces. These experiments confirm that bile IgX of the duck can function as antibody in response to influenza A viruses, and that its activity appears to be independent of serum IgM. Its possible relevance in determining survival of virus in the intestine is discussed.

Animals↗
PubMed1987

Activity of the alternative complement pathway during mycobacterial infections in inbred mice.

The relationship between kinetic activity of the alternative pathway (AP) of complement and susceptibility to Mycobacterium bovis (BCG) and M. fortuitum was examined in inbred mice. After subcutaneous injection of BCG, the organisms were mostly contained by the draining lymph nodes, with minimal effects on spleen and no apparent relationship with serum AP. After intravenous injection of BCG or M. fortuitum, male mice, which had a more effective AP than female mice, showed lower spleen bacterial counts. AP kinetics became faster in mice with high spleen bacterial counts and slower in mice with low counts, suggesting that infection or inflammatory processes affected AP. These experiments suggest that if tuberculosis is confined to tissues and draining lymph nodes AP plays no part in pathogenesis or host resistance, but AP might reduce the infectivity of low numbers of organisms spreading by blood or lymph from a primary focus of infection.

Animals↗
PubMed1986

Duck lymphocytes. I. Purification and preliminary observations on surface markers.

High yields of lymphocytes were obtained by centrifuging duck blood, collected into an equal volume of heparinized phosphate-buffered saline, over Ficoll-diatrizoate, sg. 1.077, for 25 min at 200 X g. These lymphocytes did not form E rosettes under a variety of conditions, or EA rosettes with sheep erythrocytes sensitized with rabbit antibodies. High proportions (50-80%) of blood and organ (thymus, bursa of Fabricius, spleen, cervical lymph node) lymphocytes had surface immunoglobulin (SmIg). The proportion of blood lymphocytes with SmIg was reduced (to 16-73%) by previous incubation in serum-free medium; less reduction occurred after similar incubation of organ lymphocytes. With or without previous treatment with neuraminidase duck lymphocytes did not express receptors for Helix pomatia lectin. However, some untreated lymphocytes did have receptors for peanut agglutinin (PNA) and the number was increased after desialation. The proportions and organ distribution of lymphocytes with SmIg or receptors for PNA did not follow a pattern consistent with any expected distribution of T and B cells. Duck blood lymphocytes were separated into 2 bands (mean densities 1.026 and 1.068 g/cm3) in Percoll gradients. These did not differ in expression of SmIg and receptors for PNA, but only the upper band (sg. 1.026) responded to phytohaemagglutinin, concanavalin A, pokeweed mitogen and rabbit anti-duck immunoglobulin serum in lymphocyte transformation tests. Blood lymphocytes were also separated according to their adherence to nylon wool. There was no difference in surface markers between the adherent and non-adherent cells, but only the adherent population responded to mitogens. It is suggested that since ducks are phylogenetically close to the amphibians and reptiles their lymphocyte populations may not express surface markers similar to those of chickens and mammals.

Animals↗
PubMed1986

Bile immunoglobulin of the duck (Anas platyrhynchos). I. Preliminary characterization and ontogeny.

Immunoglobulin (Ig) of a single class was found in duck (Anas platyrhynchos) bile. Its molecular weight was 890,000; serum IgM was 800,000. Heavy chains were 75,000 for bile Ig, 86,000 for IgM, 67,000 for 7.8S IgG and 37,000 for 5.7S IgG. Antigenic comparison showed that bile Ig resembled IgM but carried additional determinants. The ontogeny of bile Ig was distinct from that of serum IgM and IgG. Thus, duck bile Ig appears to be an IgM-like molecule secreted independently of serum Ig.

Animals↗
PubMed1985

A comparative study of complement activation.

Antisera to sheep erythrocytes (E) were raised in cattle, rabbits, mice, hamsters, guinea-pigs, ferrets, badgers, hedgehogs and fowls. Cross activation of total haemolytic complement (THCA) examined all combinations of sensitized sheep E and normal sera (including human); kinetic assays examined the lysis of E sensitized with rabbit antibodies. From the same species, all combinations of normal serum and xenogeneic E were used to measure total alternative pathway activity (TAPA); TAPA was also activated by rabbit and sheep E in titrations and in agarose gels, and examined kinetically against rabbit E. Ox, rabbit and fowl sera were low in THCA, guinea-pig complement was universally active, while human complement showed marked selectivity; ferret, badger and hedgehog sera were activated to high titres but probably via the alternative pathway. In studies of TAPA an inverse relationship existed between serum complement activities and the activating abilities of E from the same species. The most efficient activators of alternative pathway were E from rabbits and laboratory rodents, while the sera with broadest response were badger, ferret and fowl. Kinetic studies of TAPA showed that initiation of lysis and subsequent completion of lysis could occur with different efficiencies, suggesting these events reflected separate events in complement activation.

Animals↗
PubMed1985

Environmental silica in badger lungs: a possible association with susceptibility to Mycobacterium bovis infection.

Badger lungs contain dark granular foci (0.2 to 2.0 mm) comprising aggregates of enlarged macrophages containing birefringent crystalline particles. Particles were examined from the lungs of three badgers; many were silicates and a significant number were pure silica (SiO2). The particles and the accompanying pathology resembled mixed dust fibrosis and silicosis in humans, diseases associated with increased susceptibility to tuberculosis.

Animals↗
PubMed1985

Acute haemodynamic effects of nifedipine at rest and during maximal exercise in patients with chronic cor pulmonale.

The pulmonary hypertension of cor pulmonale can be reversed by sustained correction of hypoxia but continuous oxygen treatment poses problems in clinical practice. Alternative methods of relieving pulmonary vasoconstriction have therefore been explored. Eight patients with chronic cor pulmonale (five of them men) were studied to measure the haemodynamic effects of the calcium antagonist nifedipine, both at rest and on maximal, symptom limited exercise. The mean duration of exercise was unchanged by nifedipine (7.8 (SD 3.3) compared with 7.3(3.1) min). Cardiac output rose from 5.2(1.5) l min-1 to 8.6(3.3) 1 min-1 on exercise. Nifedipine increased resting cardiac output by 26%, but did not influence maximal exercise output. It did not significantly alter resting mean pulmonary artery pressure but reduced the level during exercise from 67(15) to 52(11) mm Hg. Nifedipine lowered resting pulmonary vascular resistance (PVR) by 32% and exercise PVR by 28%. It reduced supine mean systemic arterial pressure by 17%, standing pressure by 22%, and pressure at the maximal exercise level by 20%. Nifedipine lowered supine systemic vascular resistance (SVR) by 35%, standing SVR by 28%, and exercise SVR by 20%. Haemodynamic changes were achieved without adverse symptoms, alteration in arterial PO2, or impairment of calculated oxygen delivery. Nifedipine therefore reduced both pulmonary and systemic vasomotor tone at rest and during exercise. It did not alter exercise tolerance, which is probably limited by underlying respiratory disease. It seems possible therefore that nifedipine could delay the development of cor pulmonale, although this hypothesis remains to be tested.

Adult↗
PubMed1985

The skin inflammatory response of the badger (Meles meles).

Twenty-five badgers, captured in an area where they had been implicated in outbreaks of bovine tuberculosis, received intradermal inoculations of control medium, 150 micrograms phytohaemagglutinin (PHA), 40 units streptokinase/10 units streptodornase (SK/SD), 200 micrograms purified protein derivative of Mycobacterium bovis (PPD), Freund's incomplete adjuvant (IFA), and Freund's complete adjuvant (CFA), each in 0.1 ml of inoculum. The reactions were assessed by skinfold thickness and skin histology 30 min--7 days after inoculation. Control medium caused slight cellular reaction, mostly polymorphonuclear leucocytes (PMNs), but no significant increase in skinfold thickness. SK/SD provoked no reaction. PHA stimulated a marked increase in skinfold thickness; the cellular reaction was predominantly PMNs, with some macrophages occurring after several days. IFA and CFA promoted a long-lasting increase in skinfold thickness, and a mixed histological picture of PMNs and macrophages; later in the response, especially to CFA, giant cells and some lymphocytes occurred. PPD stimulated a small increase in skinfold thickness with a timing (2-3 days) consistent with delayed hypersensitivity (DTH); there was, however, no erythema or palpable oedema or induration. The histology was an initial multifocal reaction of PMNs with a later phase of lymphocytes and macrophages with some granuloma formation. Other cell types (eosinophils, basophils) were seen in varying proportions in all reaction sites. M. bovis was isolated from four badgers; the cellular reaction to PPD was stronger than in uninfected animals, but other aspects of the skin response were unaffected. This study shows the capacity of badgers for strong inflammatory responses, and is the first report of a DTH response to PPD in this species.

Animals↗
PubMed1984

Human intestinal parasitism in three areas of Indonesia: a survey.

Stools from 1387 people were examined quantitatively for eggs of nematode parasites. The people were residents of Padangganting, near Sawahlunto, Sumatra (227 people), Sukamaju and Cibungur rubber plantations near Sukabumi, Java (831 people) and the villages of Mahima and Rabo near Reo, Manggarai, Flores (329 people). Ascaris lumbricoides, Trichuris trichiura and Necator americanus were common; Ancylostoma was not observed. Prevalence of parasitism was highest in Java and lowest in Flores. Egg counts were low, suggesting low worm burdens; intensity of infection with Ascaris and Trichuris was highest in Java, while hookworm was highest in Sumatra. Ascaris infections decreased and hookworm infections increased in prevalence and intensity with age; Trichuris was unaffected. A sex-related difference was observed only in Sumatra, where more females than males were infected with Ascaris. Village-to-village variation in prevalence of nematode infestation was observed in Flores and on the Sukamaju plantation; the topography of other areas did not allow for village comparisons. Ad hoc anthelmintic treatment of the residents of Cibungur plantation was reflected in reduced parasitism by Ascaris and Trichuris, but not hookworm, compared with neighbouring Sukamaju. Comparison of the patterns of disease in the three areas, in terms of the occurrence of single, double or triple infections, revealed marked differences. In Java most people with parasitism had triple infections. In Sumatra the most common expression of parasitism was single infection with hookworm. In Flores single infection with Ascaris prevailed. It is suggested that the clinical effects of intestinal parasitism might depend on the pattern of infection. Samples collected in Flores were also examined for protozoa which were found in about half the population; Entamoeba coli and E. histolytica were most common.

Adolescent↗