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Biomedical subjects

R Higgins

Publications and source records attributed to R Higgins.

At least 163 records · Page 9Linked to original sources
PubMed1988

Pathology of stranded beluga whales (Delphinapterus leucas) from the St. Lawrence Estuary, Québec, Canada.

From June 1983 to May 1986, thirteen carcasses of stranded beluga whales from a polluted area of the St. Lawrence River, Canada were necropsied. High performance liquid chromatography was performed on the brains of three other animals to determine concentrations of benzo a pyrene (BaP). Two juvenile animals had severe multisystemic lesions one of which, a severe necrotizing dermatitis, was associated with a Herpesvirus-like particle. Four adults had five varieties of tumours. An adult had a systemic nocardiosis and a juvenile was affected ty a non 0:1 Vibrio cholerae septicemia. High concentrations of BaP adducts were found in the brains which were analyzed. Occurrence of BaP adducts in the brain of three whales of this population coincides with the high incidence of tumours. This and the previous finding of high concentrations of organochlorine in the tissues of these animals suggest an important role of industrial contaminants in the recent decrease of this population.

Animal Diseases↗
PubMed1988

Isolation of Streptococcus suis from diseased pigs in Canada.

A total of 260 isolates of streptococci collected over a 9-year period from diseased pigs submitted for necropsy were studied. Seventy-seven percent of isolates were identified as S. suis and 32% of S. suis isolates were retrieved in pure culture. S. suis was found more frequently in lungs and was often isolated in conjunction with Actinobacillus pleuropneumoniae, Pasteurella multocida, Escherichia coli and other microorganisms. A total of 151 (76%) of S. suis isolates could be serotyped within the 9 recognized serotypes. Serotype 2 was the most prevalent with 33%, followed by serotypes 3, 5 and 7. All isolates were sensitive to ampicillin, penicillin, cephradine, chloramphenicol and trimethoprim-sulfamethoxazole. Resistance to streptomycin, neomycin and tetracycline appeared to be very high.

Animals↗
PubMed1988

Biochemical and toxigenic characteristics of Aeromonas spp. isolated from diseased mammals, moribund and healthy fish.

In this study we describe biochemical, toxigenic and surface characteristics of 33 motile Aeromonas isolated from diseased mammals, 3 from moribund marine mammals, 24 from healthy fish and 4 from moribund fish. Aeromonas hydrophila, A. caviae and A. sobria were isolated from both mammals and fish but at a different incidence. Aeromonas hydrophila was the predominant species isolated from clinical specimens; it was isolated from pneumonia, wound infections, septicemia and abortion in horses, cattle and pigs. Aeromonas sobria was isolated from one mammal and 11 healthy fish. Aeromonas caviae was isolated in 2 cases from healthy fish and in 9 cases from diseased mammals. Variations in some biochemical tests including sorbitol, amylase and citrate, were observed between isolates from different sources. However, these differences did not allow the differentiation of isolates from diseased mammals and healthy fish. The majority of A. hydrophila isolates produced different extracellular products; A. sobria isolates produced less exotoxin. With A. caviae isolates no hemolysin, protease, enterotoxin or elastase were detected. There was no quantitative difference in hemolysin, protease, enterotoxin or elastase production between isolates from mammals and fish. It is suggested that A. hydrophila could be a potential pathogen for domestic animals, and fish may represent a potential reservoir of infection.

Aeromonas↗
PubMed1988

Chronic contained rupture of an abdominal aortic aneurysm presenting as a lower extremity neuropathy.

Rupture of an abdominal aortic aneurysm often presents with a pulsatile abdominal mass, abdominal pain, and hypotension. Recent clinical reports describe patients with less apparent clinical signs and symptoms who were found later in their evaluation to have a contained rupture of an abdominal aortic aneurysm. Even more unusual is a chronic contained rupture of an abdominal aortic aneurysm. Our patient had a chronic contained rupture of an abdominal aortic aneurysm that presented with erosion into the lumbar vertebral bodies and subsequent lumbar neuropathy. CT scan confirmed the contained rupture of the aortic aneurysm and the patient underwent successful repair of his aortic aneurysm. Our report discusses the significance of atypical presentations of abdominal aortic aneurysm rupture and the importance of prompt diagnosis and definitive repair.

Aged↗
PubMed1988

Electron microscopic examination of capsular material from various serotypes of Actinobacillus pleuropneumoniae.

The capsular material on PPLO broth-grown cells of Actinobacillus pleuropneumoniae representing serotypes 1 to 10 was visualized by transmission electron microscopy after polycationic ferritin labeling and also after stabilization with specific antibodies. All the isolates examined were covered with a layer of capsular material whose thickness varied between 80 to 90 nm and 210 to 230 nm when examined by immunostabilization. We were also able to visualize A. pleuropneumoniae in lungs of infected pigs and to estimate the amount of capsular material covering the cells. Our results indicate that differences in capsular structure exist among the different A. pleuropneumoniae serotypes, and this result may explain in part why the serotypes are not equally virulent.

Actinobacillus↗
PubMed1988

Quantitation of serotype-specific and cross-reacting group-specific antigens by coagglutination and immunodiffusion tests for differentiating Actinobacillus (Haemophilus) pleuropneumoniae strains belonging to cross-reacting serotypes 3, 6, and 8.

There are strong cross-reactions among strains of Actinobacillus pleuropneumoniae belonging to serotypes 3, 6, and 8. Various serological tests were used to differentiate these serotypes from each other. Tube agglutination, coagglutination, and indirect hemagglutination tests were not sufficiently sensitive to differentiate strains of serotypes 3, 6, and 8. However, higher antibody titers were obtained with a 2-mercaptoethanol agglutination test in homologous rabbit antisera. Absorption of immune sera with homologous and heterologous serotypes as well as quantitative estimation of antigenic activity in the unheated and heat-treated bacterial cell suspensions of reference strains with rabbit homologous and heterologous antisera revealed serotype-specific and cross-reacting group-specific antigens. Usually, serotype-specific antigens were major and dominant over group-specific antigens. The coagglutination test could be used quantitatively to measure the ratio of serotype-specific and group-specific antigens with rabbit hyperimmune sera against serotypes 3, 6, and 8. The highest antigen content for a particular serotype reflected serotype-specific antigen. For strains showing equal amounts of antigen for two or more serotypes in the coagglutination test, the immunodiffusion test with boiled cell-saline extract as the antigen and rabbit antisera against whole-cell suspensions of serotypes 3, 6, and 8 clearly revealed the serotype-specific antigen. It is suggested that coagglutination and immunodiffusion tests could be used successfully to determine the exact serotype of strains belonging to serotypes 3, 6, and 8.

Actinobacillus↗
PubMed1988

Serologic studies of Actinobacillus (Haemophilus) pleuropneumoniae strains of serotype-3 and their antigenic relationships with other A pleuropneumoniae serotypes in swine.

Serotype-3 strains of Actinobacillus (Haemophilus) pleuropneumoniae possess epitopes shared with almost all other Actinobacillus serotypes. Common epitopes detected in particulate antigens were heat-labile and heat-stable and were of minor nature. Additional cross-reactive epitopes were detected in soluble and particulate antigens prepared from strains of serotypes 3, 6, and 8. Cross-reactions occurring between serotype-3 antigens and those of other serotypes were of 2 types: one associated mainly with 2-mercaptoethanol (2-ME)-sensitive IgM antibodies and the other associated mainly with 2-ME-resistant IgG antibodies. The cross-reactivity between serotypes 3, 6, and 8 was associated mainly with IgG antibodies, as shown by the results of 2-ME tube agglutination, 2-ME-indirect hemagglutination, and coagglutination tests. None of the tests was entirely satisfactory for serotyping serotype-3 isolates, mainly as a result of overlapping of type-specific antigenic determinants of serotypes 3, 6, and 8 in different combinations in the same strain. A combination of tests, using particulate and soluble antigens, may be necessary for typing of serotype-3 isolates.

Actinobacillosis↗
PubMed1988

Minimal inhibitory concentrations of antimicrobial agents against Actinobacillus pleuropneumoniae.

Forty-five isolates of Actinobacillus pleuropneumoniae were tested for susceptibility to 12 antimicrobial agents using a microdilution method for the minimal inhibitory concentration determinations. These results confirmed the high prevalence of A. pleuropneumoniae strains resistant to antibiotics as reported earlier using the disc diffusion method (Kirby-Bauer method). While 36% of the isolates were resistant to the penicillins, 47% were resistant to chloramphenicol and 68% were resistant to tetracycline. Minimal inhibitory concentrations for the resistant isolates were approximately 32 times higher than those for the susceptible isolates to the above antibacterial agents. The isolates were in general weakly susceptible or resistant to spectinomycin, lincomycin, tiamulin and spiramycin whereas most of them were susceptible to gentamicin, trimethoprim and erythromycin. The susceptibility pattern was similar throughout the 1980 to 1984 period. The 14 serotype 5 isolates were more resistant to tetracycline but less resistant to chloramphenicol and the penicillins than the 28 serotype 1 isolates.

Actinobacillus↗
PubMed1987

Effect of heat treatment on the surface antigens of Haemophilus pleuropneumoniae.

Coagglutination and ring precipitation tests were used to study the effect of heat on the surface antigens of Haemophilus pleuropneumoniae strains employing the reference strains belonging to serotypes 1 to 7 and field isolates belonging to serotypes 1, 2, 3, 5, 6 and 7. By immunising rabbits with formalin-fixed whole-cell suspension, antibodies were obtained which sensitised Cowan I Staphylococcus aureus to coagglutinate antigen preparations which had not been heated, or heated at 56 degrees C, or boiled or autoclaved. Similar positive reactions were obtained with the ring precipitation test. Heating the cultures at 56 degrees C for one hour was best for exposing the most potent serotype-specific antigens in all the strains studied. All the reference strains and most of the field isolates possessed the thermostable type specific antigens which could withstand autoclaving for one hour. However, many field isolates belonging to serotype 1 did not possess this antigen. The apparent antigenic heterogeneity of serotype 1 strains based on the presence or absence of these thermostable antigens could be valuable in epidemiological investigations. It was shown that most potent serotype-specific antigens are present as freely diffusible material on the surface layer of the bacterial cells, which could easily be removed by washing in saline solution. Well washed bacterial cells devoid of surface materials are poor antigens. It is recommended that test strains should not be heated above 56 degrees C for serotyping because higher temperatures are liable to destroy the capsular antigen of some strains and render the culture untypeable.

Agglutination Tests↗
PubMed1987

Isolation of leptospires from nephritic kidneys of beef cattle at slaughter.

Of 955 beef cattle slaughtered at an abattoir in Quebec from May to August 1985, 122 (13%) had lesions of focal interstitial nephritis. Nephritic kidneys were collected for leptospiral culture, and matching blood samples were examined serologically. Leptospires were isolated from the kidneys of 35 (29%) cattle. Antibodies to Leptospira interrogans serovar hardjo were found in 29 (24%) cattle and to pomona in 13 (10%).

Animals↗
PubMed1987

An evaluation of agglutination and coagglutination techniques for serotyping of Haemophilus pleuropneumoniae isolates.

A comparative evaluation of rapid slide agglutination, tube agglutination, 2-mercaptoethanol tube agglutination, and coagglutination tests was made for serotyping isolates of Haemophilus pleuropneumoniae. The results indicated that a majority of the isolates could be serotyped by any of these tests. But, it was not uncommon to find isolates which were inagglutinable or poorly agglutinable in homologous sera. Heat treatment of whole-cell suspensions of such isolates was essential to unmask the serotype-specific antigenic determinants; however, in the process of heat treatment, cross-reactive common antigens of minor nature were also exposed. The antibodies involved in such cross-reactions were mainly of immunoglobulin M type, because the cross-reactivities were completely abolished in coagglutination and 2-mercaptoethanol agglutination tests. Thus, both these tests were satisfactory for serotyping inagglutinable mucoid strains. For serotyping strains which were either polyagglutinating or autoagglutinating, agglutination tests could not be used, but the coagglutination test proved to be satisfactory. The coagglutination test was serotype-specific, sensitive, simple, rapid, reproducible, and easier to read and interpret than rapid slide or tube agglutination tests. This test could be used to serotype mucoid, smooth, or rough isolates.

Agglutination Tests↗
PubMed1986

Biotyping of clinical isolates of Escherichia coli of animal origin, using the Analytab API 20E system.

Using the Analytab (API 20E) Enterobacteriaceae system of biochemical identification, a total of 506 Escherichia coli isolates from different animal species were coded numerically or biotyped. Fifty-four different biotypes were identified, 11 accounting for 83.1% of the isolates examined. Three of these profiles accounted for 65.3% of the isolates and were found in almost all animal species. Some of the biotypes were found in only one animal species: six in cattle, five in horses, 15 in pigs, two in sheep, two in birds, one in dogs and one in a porpoise. Biotypes, as determined here, could not be related to a particular pathology and more work is needed to assess the extent and significance of this relative biotype specificity among animal species. The use of other, more sophisticated, typing systems, i.e. plasmid "fingerprinting", or restriction endonuclease analysis of chromosomal DNA, would have to be investigated.

Animals↗
PubMed1985

Isolation and Characterization of a Cyclohexane-Metabolizing Xanthobacter sp.

An unusual Xanthobacter sp., capable of independent growth on cyclohexane as the sole source of carbon and energy, has been isolated from soil by using classical enrichment techniques. The mean generation time for growth on cyclohexane was 6 h. The microorganism showed a limited ability to utilize hydrocarbons, with only alicyclic hydrocarbons closely related to cyclohexane supporting growth. Ultrastructural studies indicated the presence of electron-transparent vesicles in the cyclohexane-grown Xanthobacter sp., but the presence of complex intracytoplasmic membranes could not be identified. A soluble inducible enzyme capable of oxidizing cyclohexane was identified in cell extracts. This enzyme had a pH optimum of 6.5, an absolute specificity for NADPH, and a stoichiometric requirement for molecular O(2) which was consistent with the formation of cyclohexanol. The enzyme showed no activity towards straight chain alkanes and only a limited activity towards unsaturated ring compounds. Enzymatic studies with cell extracts have indicated the main route of metabolism of cyclohexane by this Xanthobacter sp. to proceed via cyclohexane --> cyclohexanol --> cyclohexanone --> 1-oxa-2-oxocycloheptane (epsilon-caprolactone) --> 6-hydroxyhexanoate (6-hydroxycaproate) --> --> adipic acid. Alternative routes involving initial double hydroxylation of the cyclohexane ring may operate fortuituously but are unlikely to represent major pathways for the dissimilation of cyclohexane by this microorganism.

Journal Article↗
PubMed1984

Nutritionally variant streptococci from corneal ulcers in horses.

Of 24 isolates of nutritionally variant streptococci recovered from equine corneal ulcers, 22 were tested for growth requirements, physiological and biochemical reactions, and susceptibility to different antimicrobial agents. Satisfactory growth was obtained by supplementing blood agar and Todd-Hewitt broth with pyridoxal hydrochloride, and all of the media for the culture and the biochemical testing were supplemented with 0.002% of this substance. Biochemical patterns of 12 of the isolates resembled those of two viridans streptococcal species, Streptococcus intermedius and Streptococcus constellatus. Patterns of 10 isolates did not resemble those of any recognized viridans species. All of the isolates were inhibited by less than or equal to 0.25 microgram of erythromycin per ml, less than or equal to 4 micrograms of chloramphenicol per ml, and less than or equal to 4 micrograms of gentamicin per ml, and all but two were inhibited by less than or equal to 0.1 microgram of penicillin per ml.

Animals↗
PubMed1984

Serologic studies on brucellosis, leptospirosis and tularemia in moose (Alces alces) in Quebec.

Blood samples were obtained from 208 moose in La Vérendrye and Matane Reserves and in Laurentides Park, Quebec, Canada. Sera were tested for antibodies to Brucella abortus, Leptospira interrogans serovar ballum, canicola, grippotyphosa, hardjo, icterohaemorrhagiae and pomona, and Francisella tularensis. Fifteen sera contained evidence of prior exposure to F. tularensis. Only one animal was a seroreactor to L. interrogans serovar grippotyphosa and none of them had antibodies to B. abortus.

Animals↗
PubMed1984

[Relationship with the patient with bronchopulmonary cancer. Psychological, family and social aspects].

The relationship with a patient suffering from bronchopulmonary cancer is often difficult for the pulmonary physician. This is because of the gloomy prognosis, the unpleasant reputation of the disease, the length of treatment and its efficacy. The quality of life of the patient depends to a great extent on the manner in which he perceives his illness, participates in the treatment and lives through the various stages of this approach till death. The doctor ought to be the guardian of hope, a hope which changes its form and objective as the disease progresses, all of which lead the patient to an understanding of the gravity of the disease and both enables him to talk about it, while maintaining a confident relationship with the doctor. This double requirement of "truth" from doctor and patient should be present from the onset, till the terminal phase. The whole medical team is concerned with this relationship. A conversation with one person may make the patient fear for any therapeutic hopes, and against those objectives which might have tempered the distress which had risen by an impression of therapeutic impotence. With the family communication is also full of tricky points. The principal preoccupation of the doctor is to preserve the relationship established with the patient. This accompaniment demands great availability and above all a lot of time.

Attitude to Death↗