Biomedical subjects

S B Kreissig

Publications and source records attributed to S B Kreissig.

5 recordsLinked to original sources

PubMed1996

Application of the bootstrap to calibration experiments.

In calibration experiments, a number of samples of known concentration are used to establish the relationship between a measured response and sample concentration; this relationship is then used to estimate the unknown concentration of further samples from their measured responses. In addition to the estimates themselves, it is useful to have available some measure of their precision, usually given in the form of confidence limits. The standard method of inverting prediction limits is found to work well in simple situations, but in nonlinear multivariate calibration it becomes intractable. The bootstrap offers an alternative methodology, but in the calibration framework its application is not obvious. We describe some considerations in bootstrapping calibration data and compare our methods with a previous attempt and with the standard method in linear, nonlinear, and multivariate situations. The bootstrap is found to be a useful tool in those situations where the standard method is difficult to implement.

Calibration↗

PubMed1995

Generation of an expression library in the baculovirus expression vector system.

The construction and screening of a small cDNA library consisting of 2 x 10(4) clones in the baculovirus expression vector system are described. This library consists of antibody heavy chain sequences isolated from the spleen of a mouse immunized with tetanus toxoid fragment C. A portion of this library was used to produce a pool of recombinant baculoviruses which were screened for production of antibody fragments reactive to tetanus toxoid without prior expression in Escherichia coli. The pool of 30 clones was found to contain at least 6 different populations of antibody indicating that diversity existed within the library. Positive clones were isolated from the baculovirus system and confirmed as being capable of producing a tetanus reactive antibody by expression as a beta-lactamase fusion protein in E. coli. One of these clones was returned to the baculovirus system using a different transfer vector, and tetanus binding reconfirmed. The results presented here show that the concept of the construction and screening of a baculovirus expression library is feasible even with 'difficult' proteins, such as antibody heavy chain fragments, and that the baculovirus expression vector system has the potential to produce cDNA expression libraries which can be screened directly for the desired protein.

Animals↗

PubMed1995

Nucleotide sequence of the variable region of the heavy and light chains of a monoclonal IgG antibody reactive to herbicides, terbutryn and prometryn.

Members of the triazine family of herbicides are reliable indicators of contamination of the ground water or soil with pesticide residues. To facilitate better detection of the chemical residues using improved immunoassay procedures, several monoclonal antibodies against triazine herbicides have been developed. K1F4 is a hybridoma secreting monoclonal (IgG) antibody reactive to terbutryn and prometryn, two members of the triazine family. We have cloned the genes encoding the variable regions of the heavy and light chains of this monoclonal antibody and report the nucleotide sequence here.

Amino Acid Sequence↗

PubMed1994

Extension of the four-parameter logistic model for ELISA to multianalyte analysis.

The standard implementation of enzyme-linked immunosorbent assay (ELISA) for single analytes can lead to false conclusions if cross reacting compounds are present in the sample. This paper discusses the extension of the usual four-parameter logistic model for ELISA to the case of multiple cross-reacting analytes. The use of the extended model in multianalyte analysis (MELISA) is illustrated and compared with a more simplistic approach. Data on the analysis of a binary mixture of s-triazines suggests the superiority of the proposed model. This model is also suitable for other forms of immunoassay that use the four-parameter logistic curve.

Cross Reactions↗

PubMed1993

Cloning, sequencing and expression of the Fab fragment of a monoclonal antibody to the herbicide atrazine.

The Fab region of an IgG2b antibody (AM7B2.1) reactive to the herbicide atrazine was cloned into a plasmid vector using the polymerase chain reaction and two sets of degenerate oligonucleotide primers designed to mimic the amino acid variation at the N-termini of kappa L-chains and gamma H-chains. These primers also provide a secretion signal fused precisely to the antibody gene sequence for secretion of the mature antibody. A further set of universal oligonucleotide primers was developed for the direct sequencing of the VH and CH1 regions of gamma H-chains and the VL and CL regions of kappa L-chains without subcloning and were used to determine the sequence of this antibody. The kappa L-chain was found to not possess a conserved Cys residue at position 23 and the implications of this observation are discussed. The cloned genes were expressed in Escherichia coli using a commercially available T7 RNA polymerase-based plasmid. The clones were also expressed in a T7 RNA polymerase-based system containing an attenuated version of the T7 RNA polymerase promoter, plus a lac promoter placed in an antisense orientation, to enhance plasmid stability. The expressed products were confirmed as atrazine reactive by binding to an atrazine derivative conjugated with alkaline phosphatase.

Amino Acid Sequence↗