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Biomedical subjects

A D Sutherland

Publications and source records attributed to A D Sutherland.

At least 37 records · Page 2Linked to original sources
PubMed1991

Vaccine containing iron-regulated proteins of Pasteurella haemolytica A2 enhances protection against experimental pasteurellosis in lambs.

A vaccine containing sodium salicylate extract (SSE) of Pasteurella haemolytica A2 cells grown in a medium chemically depleted of available iron by the addition of alpha alpha dipyridyl to induce iron-regulated proteins (IRPs) conferred protection to specific pathogen-free (SPF) lambs exposed to an aerosol of P. haemolytica A2. The disease score in these lambs was significantly lower (p less than 0.005) than those in unvaccinated lambs or in lambs immunized with SSE prepared from cells grown in iron-replete medium. Immunoblotting of sera from these SPF lambs against whole cell antigens of P. haemolytica A2 grown under iron-restricted conditions demonstrated that antibodies to IRPs were present only in the sera of animals immunized with SSE-IRP. The antibody profile of sera from the SSE-IRP group was similar to that obtained with serum from a lamb which had recovered from P. haemolytica A2 disease produced experimentally. Negligible levels of cytotoxin-neutralizing and bactericidal antibodies were detectable in the SSE-IRP group and therefore appear not to be involved in the protection observed in this experiment.

Animals↗
PubMed1991

Identification and localization of an iron-regulated 35 kDa protein of Pasteurella haemolytica serotype A2.

Iodination of intact Pasteurella haemolytica serotype A2 cells labelled a sub-set of total cellular proteins. Comparison of the autoradiographic patterns obtained from iodinated cells grown on complete medium and on iron-depleted medium showed that expression of three proteins, of 100, 70 and 35 kDa, respectively, was increased by growth under iron-depleted conditions. Of these proteins, that of 35 kDa had not been reported previously. Like the 100 and 70 kDa proteins, the 35 kDa protein was expressed in natural infections, since it was recognized by antiserum from sheep that had recovered from an experimental infection with P. haemolytica A2. The 35 kDa protein was partially purified by reverse-phase HPLC and was found to be antigenic in both sheep and mice. A monoclonal antibody that was specific for the 35 kDa protein was used to identify the cellular location of the protein by immunoblotting of cell fractions enriched for particular cellular components. This demonstrated that the 35 kDa protein was located mainly in the periplasm.

Animals↗
PubMed1990

A colourimetric, microplate assay for the leucotoxin of Pasteurella haemolytica.

Culture supernates of Pasteurella haemolytica, which contain leucotoxin, inhibited the reduction of nitroblue tetrazolium (NBT) by bovine and ovine but not rabbit leucocytes in response to phorbol 12-myristate 13-acetate (PMA). Culture supernates of P. multocida, which contain no leucotoxin, had no inhibitory effect on the response of leucocytes from any species. The inhibition of NBT reduction was assessed visually or spectrophotometrically in the wells of microplates and used as a simple assay for leucotoxin. It was as sensitive as the trypan blue dye-exclusion method and did not require the use of radioisotopes. In addition, sera from P. haemolytica-infected calves inhibited leucotoxin activity in the microplate assay. Thus, inhibition of NBT reduction after stimulation of ruminant leucocytes with PMA can be used as a simple, specific assay for leucotoxin and for anti-leucotoxin antibodies.

Animals↗
PubMed1990

Bactericidal activity in the sera of mice vaccinated with Pasteurella multocida type A.

The susceptibility of Pasteurella multocida to killing by serum and the ability of protective vaccines to stimulate this mechanism of immunity in mice were investigated. P. multocida type of bovine origin was used to prepare a vaccine incorporating heat killed organisms and for homologous infection of mice. Bactericidal capacity and ELISA antibody titres were determined for individual mouse sera. Protection was clearly associated with bactericidal antibodies raised by vaccination. The bactericidal assay may be useful as a rapid, simple screening test of vaccinated mice for functional protective antibody levels.

Animals↗
PubMed1990

The susceptibility of in vivo-grown Pasteurella haemolytica to ovine defence mechanisms in vitro.

Pasteurella haemolytica organisms grown in vivo were examined for their susceptibility to ovine immune mechanisms in vitro. Compared with in vitro grown organisms they were less susceptible to opsonophagocytosis and, in contrast, susceptible to complement-dependent killing in the absence of exogenous antibody. These differences were not associated with phenotypic changes in the surface of the bacterial cell. However, overproduction and de novo synthesis of proteins was observed in in vivo grown organisms. Also, bound host-immunoglobulin was observed on in vivo grown organisms and a role for this in modifying the interaction with immune mechanisms is discussed.

Animals↗
PubMed1990

Cotrel-Dubousset instrumentation and vertebral rotation in adolescent idiopathic scoliosis.

We have studied 34 consecutive patients receiving Cotrel- Dubousset instrumentation for a single and flexible thoracic scoliotic curve, evaluating the rib hump deformity from a single CT scan through the apical vertebra of the curve. Using two measures of rotation we found a mean improvement of 25% in the rotation of the vertebra after operation. Any, usually minor, deterioration occurred in the first six months postoperatively, and there was no significant further deterioration in 19 patients assessed over two years after surgery. Cotrel-Dubousset instrumentation can produce a significant correction of vertebral rotation and of the associated rib hump deformity.

Adolescent↗
PubMed1989

Protection of lambs against experimental pneumonic pasteurellosis by transfer of immune serum.

Passive protection of specific pathogen-free lambs against experimental pasteurellosis was achieved using antisera from conventionally reared sheep which were either convalescent from experimental pneumonia or inoculated with Pasteurella haemolytica A2 vaccines. The complete immune sera, or immunoglobulin-rich fractions prepared from them, when administered separately or together provided 94-100% protection of recipients compared to control lambs. Antibodies to P. haemolytica in donor sera were quantified by anti-sodium salicylate extract (SSE) and anti-lipopolysaccharide (LPS) ELISA, bactericidal assay, cytotoxin neutralization and indirect haemagglutination. The anti-SSE ELISA titres correlated best with protective efficacy and could be used to measure antibody in recipient lambs immediately before challenge. The degree of protection was unaffected by prior infection with parainfluenza virus Type 3, suggesting that such exposure did not enhance exudation of circulating immunoglobulin into the respiratory tract. It was concluded that systemic humoral immunity alone can prevent pasteurellosis.

Animals↗
PubMed1989

A crude cytotoxin vaccine protects sheep against experimental Pasteurella haemolytica serotype A2 infection.

Three vaccines containing Pasteurella haemolytica serotype A2 antigens were tested for their ability to protect sheep against a homologous challenge. A crude cytotoxin preparation in combination with a sodium salicylate extract (SSE) or crude cytotoxin alone were highly protective (98 and 86%, respectively), whereas SSE alone was poorly (47%) protective. These findings indicated that the crude cytotoxin was an essential component of a protective vaccine. Protection correlated with serum cytotoxin-neutralising (CN) titres and bactericidal activity, which were stimulated by antigens in the crude cytotoxin preparation.

Animals↗
PubMed1988

A rapid micro-method for the study of antibody-mediated killing of bacteria, with specific application to infection of sheep with Pasteurella haemolytica.

A micro-titration plate bactericidal assay was developed to measure complement-dependent antibody-mediated killing of Pasteurella haemolytica. Sera and lung washings from specific pathogen-free (SPF) lambs convalescent from a challenge with live, virulent P. haemolytica were bactericidal in the presence of complement. Similar samples from naive SPF lambs had no such activity. Purified IgG derived from a convalescent lamb serum was as bactericidal as the whole serum. Absorption of convalescent serum with lipopolysaccharide from P. haemolytica abolished bactericidal activity, suggesting that this antigen may be a target for antibody in the bactericidal complex.

Animals↗
PubMed1987

Subacute pulmonary melioidosis in a temperate climate.

Previous reports of cases of melioidosis that were seen in nonendemic areas of Australia describe recrudescences of latent infection. We describe the case of a patient who presented in the cooler climate of Melbourne with a probable primary, subacute pulmonary infection with Pseudomonas pseudomallei. This case illustrates several points that bear consideration in the management of atypical pneumonia and, more specifically, pulmonary melioidosis. Historical and occupational clues are easily missed or unrecognized, while a persistent growth of gentamicin-resistant Pseudomonas species should arouse suspicion. Septicaemic melioidosis carries a poor prognosis, and treatment should be early and aggressive; use of the newer, third-generation cephalosporin agents should be considered. Given active support in a well-equipped intensive care unit, together with appropriate antibiotic therapy, patients may eventually be cured of this infection, but a high mortality rate is still encountered.

Anti-Bacterial Agents↗
PubMed1987

The effect of preoperative oral fluid and ranitidine on gastric fluid volume and pH.

One hundred unpremedicated daycare patients were randomly assigned to one of four groups. Between two and three hours preoperatively all patients received either oral ranitidine 150 mg, or placebo, with bromosulphthalein (BSP) 50 mg in 10 ml water, immediately followed by either 150 ml water or no further fluid. The residual gastric volume (RGV) in the two placebo groups was significantly lower in patients given 150 ml water (20.6 +/- 14.1 ml) than in those who continued fasting (29.9 +/- 18.2 ml) (p less than 0.05). The RGV was further significantly decreased in the two ranitidine groups (10.0 +/- 8.8, 9.7 +/- 10.5 ml) compared with the two placebo groups (20.6 +/- 14.1, 29.9 +/- 18.9 ml) (p less than 0.01). Mean pH values were significantly higher in the two ranitidine groups (6.71 +/- 0.99; 6.31 +/- 1.81) than in the two placebo groups (2.05 +/- 1.41; 1.72 +/- 0.33) but were not significantly different in the fluid versus non-fluid groups. In patients who ingested 150 ml water there was no correlation between the premedication interval and either RGV or pH values. The extremely low percentage of the original BSP (less than 0.9 per cent) in the gastric fluid of these patients demonstrated that gastric emptying of the ingested water was virtually complete prior to surgery. The combination of RGV of 25 ml or more with pH less than 2.5 was present in 56 per cent of patients who had only a sip of water with placebo, in 28 per cent of those who received 150 ml water with placebo, and in only two per cent of those patients who received ranitidine.

Adult↗
PubMed1986

Immunity of specific pathogen-free lambs to challenge with an aerosol of Pasteurella haemolytica biotype A serotype 2. Pulmonary antibody and cell responses to primary and secondary infections.

Specific pathogen-free (SPF) lambs previously exposed to an aerosol of P. haemolytica biotype A serotype 2 (A2) were immune to subsequent challenge with an aerosol of P. haemolytica A2. Untreated control lambs were not immune to this challenge. The local immune responses of the lung to these challenges were examined. High IgG and IgA titres to P. haemolytica and high levels of opsonizing antibody against P. haemolytica were present in the lung washings from previously infected immune lambs at autopsy, seven days after the second infection. Lung washings from control lambs, 7 days after challenge with P13 virus and P. haemolytica A2, had no IgG titres, very little opsonizing activity but did have IgA titres which were significantly higher than in unchallenged control lambs. The cellular response of animals challenged with P13 virus and P. haemolytica was significantly greater than that of unchallenged controls or of lambs exposed only to P. haemolytica. However, this finding was complicated by the response to P13 virus. Lymphocytes from lung washings of all lambs failed to respond in a lymphocyte stimulation test to phytohaemagglutinin while blood lymphocytes did respond. There was little specific response to P. haemolytica antigen in the test.

Animals↗
PubMed1986

Cytotoxic effect of serotypes of Pasteurella haemolytica on sheep bronchoalveolar macrophages.

Ovine isolates of the 15 known serotypes found within the A and T biotypes of Pasteurella haemolytica were cytotoxic for sheep bronchoalveolar macrophages (BAM). Weaker toxicity for the same target cells was also expressed by non-serotypable ovine isolates of P. haemolytica. The results suggest that cytotoxicity for sheep BAM is a virulence factor common to both A and T biotypes of P. haemolytica.

Animals↗
PubMed1986

Cytotoxin from an ovine strain of Pasteurella haemolytica: characterisation studies and partial purification.

A cell-free, water-soluble cytotoxin from an ovine strain of Pasteurella haemolytica biotype A serotype 1 killed sheep bronchoalveolar macrophages at 37 degrees C, but not at 4 degrees C or 22 degrees C. The cytotoxin was stable over the pH range 2-12, resistant to heat at 60 degrees C but inactivated at 100 degrees C or by autoclaving. Trypsin also destroyed the cytotoxin, which is therefore thought to contain a protein component essential for biological activity. A preliminary purification of the crude cytotoxin using gel-filtration column chromatography resulted in the isolation of a biologically active fraction which resolved as a single protein band and one carbohydrate band on non-dissociating polyacrylamide gels. However, this fraction resolved into approximately 16 component bands on a sodium dodecyl sulphate polyacrylamide gel.

Animals↗
PubMed1986

Effects of preoperative fasting on morbidity and gastric contents in patients undergoing day-stay surgery.

The effects of overnight fasting on gastric contents and on the symptoms associated with fasting were studied prospectively in female outpatients. Group A (n = 66) were patients scheduled for first trimester therapeutic abortion; group B (n = 66) were scheduled for minor gynaecological surgery. It was demonstrated that overnight fasting (15 +/- 3 h) did not guarantee an empty stomach (volume 22 +/- 13 ml) and that gastric acidity was high (pH 1.6 +/- 0.5). Gastric volumes and pH were the same in both groups. Group A patients had a higher incidence of preoperative nausea and vomiting (P less than 0.001). Before anaesthesia, 50% of all patients had symptoms of moderate to severe hunger, while 44% of patients had symptoms of moderate to severe thirst. Neither the severity of symptoms of fasting nor the duration of fast correlated with gastric volume or pH. Patients in group A had significantly greater symptoms of hunger; however, they also had fasted for significantly longer (P less than 0.002).

Adult↗
PubMed1986

Assessment of immunity to Pasteurella haemolytica in sheep by in vitro methods.

The sera of conventionally-reared sheep which had been experimentally infected with Pasteurella haemolytica serotype A2 and Mycoplasma ovipneumoniae were compared with those of animals from the same source which had been vaccinated 3 times with an alhydrogel-adsorbed mixture of cell-wall extract and heat-killed cells of P. haemolytica A2 emulsified in Freund's incomplete adjuvant. Both groups of animals had high titres of anti-P. haemolytica A2 IgG by ELISA, high opsonic indices in a phagocytic assay involving ovine lung macrophages, and reacted with a large number of cell-wall antigens in an immunoblot test. Both types of sera also protected mice against challenge with P. haemolytica A2 in mucin. In contrast, sera from animals injected twice with a vaccine similar to the first but lacking oil adjuvant yielded much lower values in the ELISA, opsonic index and immunoblotting assays, and failed to protect mice against challenge. The correlations between the 3 in vitro tests and the passive protection test in mice suggest that evaluation of the efficacy of P. haemolytica vaccines may be possible by in vitro methods alone.

Animals↗
PubMed1986

Preoperative oral fluids: is a five-hour fast justified prior to elective surgery?

The effects of preoperative oral administration of 150 ml fluid were studied prospectively in 140 unpremedicated, ambulatory outpatients presenting for first trimester therapeutic abortion. Intraoperative gastric fluid volume, pH, and rate of gastric emptying were measured in the four groups to which patients were randomly assigned. At an average time of 2 1/2 hr preoperatively all patients received either oral ranitidine, 150 mg, or a placebo tablet, with the nonabsorbable marker dye bromosulphthalein (BSP, 50 mg in 10 ml water, followed by either 150 ml water or no further fluid. The effect of volume ingested was assessed by comparing the volume of gastric contents obtained by gastric tube suctioning at the completion of surgery in the two groups given placebos. The gastric volume was significantly less in patients given 150 ml water (17.6 +/- 14.5) than in those given only BSP (26.7 +/- 18.9) (P less than 0.02), and was further significantly decreased in the two groups given ranitidine (8.3 +/- 7.3, 9.5 +/- 7.7 ml) (P less than 0.001). Mean pH values were significantly higher in the two ranitidine groups (5.52 +/- 1.79, 5.03 +/- 1.79) than in the two placebo groups (1.75 +/- 0.94, 1.92 +/- 1.27). The combination of a residual volume of 25 ml and pH less than 2.5 was found in 46% of patients given only BSP with placebo, in 23% of those given 150 ml water with placebo, and in no patient given ranitidine. There was no correlation between the gastric volume or pH values with the ingestion-surgery interval in patients given 150 ml water.

Adult↗