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Biomedical subjects

D Armstrong

Publications and source records attributed to D Armstrong.

At least 721 records · Page 40Linked to original sources
PubMed1970

Previously uncharacterized Mycoplasma isolates from an investigation of canine pneumonia.

Mycoplasmas recovered from the respiratory tract and genitourinary system of dogs, with and without respiratory infection, have been characterized by biological and immunological methods. Some of the isolates were indentified as being similar to the three species of canine mycoplasmas described earlier under the designation Mycoplasma spumans, M. canis, and M. maculosum. Other mycoplasmas placed in three groups (A, C, and D) were found to be clearly distinct from the three classified species. Group A strains fermented glucose but not mannose and were serologically distinct from other canine mycoplasmas recovered in this study. These strains were subsequently found to be biologically and serologically related to a previously reported, but unclassified, canine mycoplasma. Group D strains differed in some biological properties but were serologically related. These were found to be nonfermenting mycoplasmas representing isolations from the throat and bladder of dogs. They were serologically distinct from other canine mycoplasmas and were apparently unrelated to other known mycoplasma serotypes. Group C mycoplasmas were recovered only from the lungs of dogs. Within the group, they differ in some immunological properties but appear to be serologically distinct from other canine strains. They can also be separated from other dog strains in their ability to ferment glucose and mannose. Group B strains were found to have biological properties similar to M. canis strains but seemed to be only partially related to this serotype when examined in several serological techniques. It is suggested that these strains might represent antigenic variants of M. canis.

Journal Article↗
PubMed1970

Agar-Gel Precipitating Antibody in Pseudomonas aeruginosa Infections.

The human immune response to Pseudomonas aeruginosa infection was studied by using the double diffusion in agar-gel technique. Antigens from Fisher-Devlin-Gnabasik immunotypes were prepared by both trichloroacetic acid extraction and ultrasonic disruption. Serum from 72 of 168 patients (43%) from whom P. aeruginosa was isolated formed from one to eight precipitin bands. Precipitins were demonstrated in the sera of 60 of 66 (91%) patients recovering from bacteremia and deep infections; however, they were usually absent when Pseudomonas infection was fatal or when there was no clinical evidence of significant infection. Precipitating antibody was detectable at serum dilutions as high as 1:32, and appearance of single bands correlated with hemagglutinating antibody titers of >/=1:128. Antigen from sonically disrupted organisms usually resulted in stronger precipitin bands than trichloroacetic acid extracts, and antigen from the homologous infecting strain occasionally increased test sensitivity. None of 50 normal controls had Pseudomonas precipitins as was the case in patients convalescing from Escherichia coli (15 patients), Klebsiella-Enterobacter-Serratia (18), and Proteus (14) bacteremias. Measurement of agar-gel precipitins was useful and specific in evaluating the circulating antibody response to P. aeruginosa infections.

Journal Article↗
PubMed1970

Characterization of canine mycoplasmas by polyacrylamide gel electrophoresis and immunodiffusion.

Canine mycoplasmas which had been characterized by biological and serological methods were further studied by using polyacrylamide gel electrophoresis (PGE) and double diffusion in agar gel. The three dog mycoplasmas previously characterized, Mycoplasma canis, M. maculosum, and M. spumans showed distinctive patterns by PGE. Five additional representative isolates from dogs had been characterized serologically and biologically into three new groups, A, C, and D. An additional mycoplasma (group B) was indistinguishable from M. canis by growth inhibition and PGE but was more broadly reactive with field isolates serologically. The group A organisms were distinctive in pattern and similar to those studied by Razin and Rottem, tentatively designated M. edwardii. The group C organisms were represented by two isolates which were similar by fluorescent-antibody studies but different by growth inhibition tests. These two isolates were also different from each other by PGE. The group D serotypes were also distinctive by PGE from all other dog mycoplasmas tested. It was found, during these studies, that two different mycoplasmas showed different PGE patterns at different intervals during incubation. Immunodiffusion studies showed a relationship among all the canine mycoplasmas, and bands of nonidentity between the two group C mycoplasmas were demonstrated.

Animals↗
PubMed1969

Multiple group-specific antigen components of avian tumor viruses detected with chicken and hamster sera.

Multiple group-specific (gs) components of the avian leukosis-sarcoma viruses were detected by immunodiffusion (Ouchterlony) tests with sera from hamsters bearing tumors induced by sarcoma viruses and with sera from adult chickens immunized with avian sarcoma or leukosis viruses. Immune hamster sera detected up to four components, whereas chicken sera detected at least one. The hamster and chicken sera identified a similar antigen, as indicated by reactions of identity. Relatively few chicken sera containing neutralizing antibody to avian sarcoma or leukosis viruses reacted in immunodiffusion with the gs antigen. The gs components were released from the virion by various means of disruption, including freezing and thawing. Tests with tissues from normal chickens and from chickens with Marek's disease failed to demonstrate any reactions with hamster or chicken gs antiserum.

Alpharetrovirus↗