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Biomedical subjects

J A Lowe

Publications and source records attributed to J A Lowe.

At least 73 records · Page 4Linked to original sources
PubMed1986

Biological monitoring of agricultural workers exposed to pesticides: I. Cholinesterase activity determinations.

An estimated 4 to 5 million persons work in agriculture; within this sector, mixers, loaders, applicators, and other workers who directly handle agricultural chemicals are at highest risk for pesticide-related illnesses. Among field workers, seasonal workers engaged in certain cultivation and harvesting operations are also at risk of exposure to pesticide residues. Biological screening for agricultural workers is limited at present to pesticide mixers, loaders, and applicators, and consists almost exclusively of measurements of cholinesterase activity to estimate inhibition by organophosphate and carbamate compounds. We review here the measurement and interpretation of cholinesterase activity in occupationally exposed populations and the correlation between cholinesterase activity and symptoms of acute and chronic illness among agricultural workers. The only state to mandate medical surveillance for agricultural workers is California: criteria for surveillance, baseline cholinesterase determination, periodicity of testing, and criteria for removal from and return to work are described, and alternative approaches for screening and clinical evaluations are discussed.

Adult↗
PubMed1986

Biological monitoring of agricultural workers exposed to pesticides: II. Monitoring of intact pesticides and their metabolites.

Analytical methods have been developed for the detection of a variety of compounds that are found intact or as metabolites in biological samples from workers exposed to pesticides. Such tests are used primarily in research settings to describe patterns of absorption, metabolism, and excretion, to derive exposure limits for occupational exposure, to evaluate the adequacy of these limits and of work practices in field settings, and to confirm the etiology of poisonings for medicolegal purposes. We review here methods used in studies of occupational pesticide exposure, with particular attention to validation in terms of dose-response relationships, to technical complexity and cost, to the requirements for analytical quality control, and to the utility of these methods for field research purposes. Biological monitoring for intact pesticides or metabolites in agricultural workers is limited to a few chemicals, notably, pentachlorophenol, methyl bromide, and chlordimeform. These programs and their use in regulation and enforcement are described.

Agricultural Workers' Diseases↗
PubMed1986

Immunogenic and antigenic epitopes of immunoglobulins. XVIII. Subpopulations of human lambda chains defined with a panel of monoclonal antibodies.

Following immunization with various lambda Bence-Jones proteins, over 100 hybridomas were established. A majority of the monoclonal antibodies (McAb) produced were demonstrated to recognize epitopes common to all lambda chains or unique to the immunogen. Twenty-nine McAb exhibited profiles of 'restricted' reactivity. Analysis with a panel of serologically defined antigens allowed McAb recognizing the lambda II subgroup to be identified. Other McAb recognized epitopes selectively expressed by lambda II and lambda III subgroup proteins. A further twenty-one McAb exhibited individual specificity profiles, some of which detect minor lambda chain subpopulations. Several of these McAb have potential for analysis of the clonality of specific antibody responses and for detecting monoclonal B-cell proliferations.

Antibodies, Monoclonal↗
PubMed1985

Variants of lymphoid lines produced with ricin A-chain monoclonal antibody conjugates.

Conjugates of ricin A-chain with monoclonal anti-light chain antibodies specifically killed cells hearing kappa or lambda immunoglobulin (Ig) light chains. Exposure of cells from B-lymphoblastoid cell lines (B-LCL) to conjugate for less than 30 h had only a slight effect on cell growth, but on 48 h exposure a marked killing effect was achieved. After recovery of growth, cells were re-exposed to conjugate for 9-14 days. Treatment of cells from the EB4 line (sIgG lambda) in this way yielded 4 variants which showed a marked reduction in levels of surface Ig lambda and secreted Ig lambda with slight, or no, reduction in MHC class II expression and similar growth rates to the parent line. Variant lines retained their phenotype over long periods of culture.

Antibodies, Monoclonal↗
PubMed1984

Immunogenic and antigenic epitopes of immunoglobulins--VII. The topographical distribution of Fc gamma epitopes and the relationship of an iso-allotypic specificity to the presence of histidine 435.

Epitopes recognised by a panel of 23 anti-Fc gamma monoclonal antibodies (McAbs) have been subdivided into three groups each having a distinct topographical distribution. One group of mutually inhibitory McAbs are reactive with epitopes expressed on the fy "surface" of the C gamma 2 domain. A second group recognises epitopes in the region of arginine 355 of the C gamma 3 domain whilst the third group recognises epitopes expressed in the inter C gamma 2/C gamma 3 domain region--as evidenced by inhibition of Staphylococcus aureus protein A binding. An antibody of the latter group reactive with IgG1, 2, 4 and IgG3m(15,16) proteins but not IgG3m(5) or IgG3m(21) proteins allows histidine 435 to be identified as a critical residue for expression of the epitope recognised by this antibody.

Animals↗
PubMed1983

Immunogenic and antigenic epitopes of immunoglobulins--V. Reactivity of a panel of monoclonal antibodies with sub-fragments of human Fc gamma and abnormal paraproteins having deletions.

The specificity of a panel of 27 monoclonal antibodies reactive with human Fc gamma has been further defined through reactivity profiles with sub-fragments of Fc gamma and IgG paraproteins having deletions within C gamma 2 or C gamma 3. Antibodies are identified that are directed to discontinuous epitopes requiring native Fc gamma for expression. Other antibodies are reactive with isolated C gamma 2 or C gamma 3 domains. Sub-class specific and sub-class restricted antibodies allow correlation of epitope expression with primary structure.

Animals↗
PubMed1976

Humoral and cellular aspects of immunoglobulin allotype suppression in the rabbit. IV. Kinetics of induction.

The injection of anti-b6 antibody into neonatal heterozygous b4b6 or b5b6 rabbits causes allotype suppression. Animals receiving a weight-related dose of antibody on day 2 or day 5 of life showed complete long-term chronic suppression of b6 immunoglobulin. Delay of injection until day 8, day 10 or day 11 of life resulted in more variable suppression, with animals showing either short- or long-term complete suppression or partial suppression. There was some correlation between levels of anti-b6 present in the circulation at day 21 and the degree of suppression obtained. Allotype suppression could be partially neutralized by injection of the paternal type immunoglobulin on days 19, 28, 30 or 43; if the injection was delayed until day 54, 66 or 79 there was no effect and chronic suppression proceeded as in control rabbits not receiving neutralizing immunoglobulin. The results indicate that the critical period for the induction of allotype suppression is between days 11 and 43 of life.

Age Factors↗