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Biomedical subjects

D M Robinson

Publications and source records attributed to D M Robinson.

At least 55 records · Page 3Linked to original sources

A monoclonal antibody for the specific diagnosis of plague.

A stable mouse-cell hybridoma was obtained that secretes an IgA monoclonal antibody reactive with the fraction 1 (F1) envelope antigen of Yersinia pestis. Titres of the antibody typically ranged from 1:32 768 to 1:65 536 in mouse ascitic fluids.The monoclonal antibody formed a line of precipitation when run against F1 antigen in Ouchterlony gel diffusion tests. In tests of 235 strains of Y. pestis, lines of identity occurred between the precipitates formed with a solution of purified F1 antigen and the F1 antigen produced by the plague strains. No precipitates formed for 65 strains that were incapable of elaborating F1 antigen. Specificity of the monoclonal antibody for strains of Y. pestis producing F1 was also indicated by negative results for 50 yersinia strains other than Y. pestis tested by an ELISA that used the antibody to capture antigen.Experiments to determine the shelf-life of the antibody were conducted over 3-4 years. When the monoclonal antibody was freeze-dried in vials, titre was retained for three years when the vials were stored at -70 degrees C but only for two months when they were stored at ambient temperatures. When the antibody was freeze-dried in wells of ELISA plates, sensitivity of the plates for capture of F1 antigen was preserved for four years when the plates were stored at -70 degrees C compared with two weeks for plates stored at room temperature. When a solution of the antibody was sealed in wells of ELISA plates and refrigerated at 4 degrees C, reactivity of the antibody and sensitivity of the plates were retained for a year.Alternatives for the application of this monoclonal antibody in ELISA and other plague diagnostic procedures are discussed.

Animals↗

Global survey of antibody to Hantaan-related viruses among peridomestic rodents.

A global serological survey of rodents was conducted to determine the distribution and prevalence of antibody to Hantaan-related viruses, which are the causative agents of haemorrhagic fever with renal syndrome (HFRS) in man. Over 1700 rodent sera from more than 20 sites worldwide were examined by immunofluorescent antibody assay. High-titred positive sera were further tested by plaque reduction neutralization tests with prototype Hantaan virus and urban rat-associated Hantaan-like virus. Antibody-positive rodents were found in most, but not all, sites sampled. The highest antibody prevalence rates were found in Baltimore, MD, USA and Bélem, Brazil, and Rattus norvegicus was the species most often found positive. Bandicota indica and B. bengalensis, species previously not recognized as hosts of hantaviruses, were also positive. Neutralization tests detected antibody in Rattus sera specific for urban rat-associated Hantaan-like virus, but failed to establish the specificity of antibody in Bandicota sera. These results indicate that Hantaan-related viruses exist beyond the currently recognized boundaries of HFRS in man and suggest that human HFRS-like disease might be occurring in other areas of the world where rodent-human contact is common.

Africa↗

Clinical and immunologic responses of silvered leaf monkeys (Presbytis cristatus) to experimental reinfection with Rickettsia tsutsugamushi.

Silvered leaf monkeys (Presbytis cristatus) that had recovered from active Rickettsia tsutsugamushi infections 14 months previously became rickettsemic when inoculated with homologous, related, or unrelated strains of R. tsutsugamushi. In contrast to the results after the initial infection that produced disease, no signs were observed after the subsequent infections. Most animals responded with detectable titers of antibody to the Karp antigen regardless of the inoculated strains. Strains recovered during rickettsemia usually had antigens related only to the challenge strains, but in three silvered leaf monkeys, antigens characteristic of both the original and the challenge strains were detected.

Animals↗

Hypothalamic-pituitary responses to high concentrations of gonadal steroids in a three-month-old infant with a feminizing gonadal stromal tumor.

A 3-month-old female infant feminized by an ovarian stromal tumor is presented. Clinicopathologic aspects of such tumors occurring in infancy are discussed. In addition, the evaluation of hypothalamic-pituitary function preoperatively and postoperatively are presented. In the preoperative, high-steroid environment, both basal and stimulated secretion of follicle-stimulating hormone (FSH) was suppressed. Secretion of luteinizing hormone (LH) was normal. Following surgical castration, stimulated secretion of both gonadotropins clearly increased. These findings suggest an active but less sensitive negative feedback mechanism for FSH than for LH during infancy, i.e., high concentrations of gonadal steroids are necessary to maximally suppress FSH secretion while normal steroid concentrations appear to maximally suppress LH secretion. Developmental changes in hypothalamic-pituitary sensitivity to negative feedback controls are discussed in light of these findings.

Female↗

Antigenic analysis by direct immunofluorescence of 114 isolates of Rickettsia tsutsugamushi recovered from febrile patients in rural Malaysia.

One hundred and fourteen Rickettsia tsutsugamushi isolates, recovered from febrile patients in central Peninsular Malaysia, were antigenically analyzed by direct immunofluorescence using eight prototype strains. Twenty-nine antigenic types were detected. The TA763, TA716, Karp and TA686 strains were the most common and occurred singly or in combination with each other or other strains in 86% of the isolates.

Antigens, Bacterial↗

Serological evidence for a high incidence of transmission of Rickettsia tsutsugamushi in two Orang Asli settlements in Peninsular Malaysia.

Two communities of Orang Asli (aborigines) in Peninsular Malaysia were observed for evidence of Rickettsia tsutsugamushi infection over periods of 1-8 mo. Sequential sera were examined for antibody by the indirect immunofluorescence test. The incidence of infection in the two self-selected populations in the two communities was calculated to be 3.9% per month and 3.2% per month.

Adolescent↗

Identification and antigenic typing of Rickettsia tsutsugamushi in naturally infected chiggers (Acarina: Trombiculidae) by direct immunofluorescence.

Rickettsia tsutsugamushi organisms were detected and typed antigenically by direct immunofluorescence in mites from laboratory-maintained infected colonies of Leptotrombidium (Leptotrombidium) fletcheri and L. (L.) arenicola. Rickettsiae were identified most readily in unengorged larvae, but were also discernable in engorged larvae and all post-larval stages of the vectors.

Antigens↗