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Biomedical subjects

P Draper

Publications and source records attributed to P Draper.

At least 91 records · Page 5Linked to original sources
PubMed1981

Demonstration of antibodies reacting with different determinants on Mycobacterium leprae antigen 7.

A purified preparation of M. leprae antigen 7 was used to investigate the specificity of anti-M. Leprae 7 antibodies in leprosy sera in a radioimmunoassay. A solution containing arabinogalactan (AG) and arabinomannan (AM) inhibited the antibodies in some sera to a great extent, whereas the antibody activity was virtually unchanged in other sera under the same conditions. These findings indicate that the antibodies are directed against different determinants on M. leprae antigen 7. Antibodies against determinants other than AG and AM occurred particularly in lepromatous leprosy sera. In 12 out of 14 sera, AG and AM had similar inhibiting capacity. In one serum, AG had markedly higher inhibiting capacity than AM; in the last serum, the reverse was the case, demonstrating variation in anti-polysaccharide specificity in individual sera.

Antibody Formation↗
PubMed1981

Comparison of 22 species of Mycobacteria by immunodiffusion against an absorbed reference leprosy serum.

Lithium acetate antigenic extracts of 22 species of acetone-treated mycobacteria were tested by immunodiffusion precipitation for reactivity with a pool of sera from treated lepromatous leprosy patients (ARLS). This ARLS had been adsorbed with M. bovis (BCG, M. vaccae, cardiolipin, and lecithin to make it specific for M. leprae when used in an indirect immunofluorescence test. The ARLS produced two precipitin lines with M. leprae extract, one of which formed a line of identity with extracts of M. lepraemurium and M. bovis (BCG). Aso, recognition without reactions of identity was produced between ARLS and M. flavecens, M. gastri, M. gordonae, and M. nonchromogenicum. The ARLS did not recognize the 15 other species including the human pathogens, M. tuberculosis, M. intracellulare, M. kansasii, M. scrofulaceum, and M. marinum. These data suggest that serologic tests for M. leprae infection might be affected by antibodies to antigens shared by M. leprae and other mycobacteria. The significance of these shared antigens will depend upon the prevalence of human immune responses to mycobacteria containing the shared antigens in any given community.

Antigen-Antibody Reactions↗
PubMed1980

Diet and medications giving positive ninhydrin reactions on TLC in a newborn urinary screening program.

During amino acid analysis of over 520,000 urine samples (provided by a urinary screening program), we often noticed different dietary compounds or medications giving positive ninhydrin reactions which could interfere with the interpretation of the thin layer chromatograms. Consequently, we have done an in vitro study of the chromatographic behaviour of the most frequently encountered artifacts in urine. We believe that the results of this work should make it easier for other laboratories doing similar analyses to recognize the presence of such compounds, thus facilitating the evaluation of their chromatograms.

Amino Acids↗
PubMed1980

An automated method for the determination of orotic acid in the urine of children being screened for metabolic disorders.

Urinary orotic acid is believed to be a valuable probe for early diagnosis of inborn errors of metabolism leading to hyperammonemia and increased pyrimidine synthesis. For the purpose of our urinary mass screening programme, we developed an automated colorimetric method which is reliable in the range of 1 to 50 micrograms/ml orotic acid and allows analyses at a rate of 160 samples per hour. Preliminary results are presented which illustrate that various disorders can be recognized by measuring orotic acid in urine.

Autoanalysis↗
PubMed1980

Glycosylated hemoglobins in Friedreich's ataxia.

In a study of glycosylated hemoglobins in Friedreich's Ataxia patients and in family members, the level was found to be higher in insulin dependent diabetics than in healthy non-diabetic control subjects (p < 0.01), but was similar to non-ataxic diabetic control subjects. Results for non-diabetic Friedreich's Ataxia patients and siblings were similar to those for non-diabetic control subjects while levels were slightly increased in the heterozygotes. It is concluded that in Friedreich's Ataxia patients and family members (apart from the insulin dependent diabetics), there was no hyperglycemia sufficient to be detected as an increase in glycosylated hemoglobins.

Diabetes Complications↗
PubMed1980

Effect of purification steps on the immunogenicity of Mycobacterium leprae.

In studies aimed at the development of an antileprosy vaccine for use in man, Mycobacterium leprae suspensions were prepared from livers of experimentally infected armadillos. The 2 methods of purification in chief use, carried out after irradiation of the tissue with 2.5 megarads of gamma irradiation from 60Co, involved treatment with 0.1N NaOH for 2 h at room temperature, trypsin and chymotrypsin digestion for 24h at 37 degrees, and separation in a 2-phase liquid polymer (dextran:polyethylene glycol) system. All vaccines were autoclaved and injected intradermally in mice. Earlier studies have shown that heat inactivation does not interfere with the immunogenicity of M. leprae. Immunogenicity was measured by foot-pad enlargement (FPE) after challenge with heat-killed M. leprae suspensions or by protection against infectious foot-pad challenge. The results indicated that the irradiation and 2-phase separation did not decrease immunogenicity but the NaOH treatment and enzyme digestion did.

Animals↗