Robust estimation of HDR in fMRI using H(infinity) filters.

Estimation and detection of the hemodynamic response (HDR) are of great importance in functional MRI (fMRI) data analysis. In this paper, we propose the use of three H (infinity) adaptive filters (finite memory, exponentially weighted, and time-varying) for accurate estimation and detection of the HDR. The H (infinity) approach is used because it safeguards against the worst case disturbances and makes no assumptions on the (statistical) nature of the signals [B.

The precursor to B-type natriuretic peptide is an O-linked glycoprotein.

Human pro-B-type natriuretic peptide (proBNP), the precursor for B-type natriuretic peptide (BNP), was expressed in Chinese hamster ovary cells (CHO) and compared by Western blot analysis to BNP cross-reacting material immunoprecipitated from the plasma of heart failure patients. Both recombinant and native forms co-migrated as a diffuse band centered around 25 kDa and were reduced to a 12 kDa species by treatment with a mixture of O-link deglycosylation enzymes. The 108-amino acid CHO-expressed protein was examined by tryptic mapping and LC-MS and found to be an O-linked glycoprotein.

Cysteine 116 participates in intermolecular bonding of the human VEGF(121) homodimer.

VEGF(121), the 121-amino acid form of vascular endothelial growth factor is a homodimer with nine cysteine residues per monomer. While three intramolecular and two intermolecular disulfide bonds have been mapped, the state of the ninth cysteine, Cys116, is not known. In this study, we determined that human VEGF(121) contains a third interchain disulfide bond between Cys116 of each monomer.

On-line procedures for alkylation of cysteine residues with 3-bromopropylamine prior to protein sequence analysis.

We have previously shown that 3-bromopropylamine offers several advantages over other alkylating reagents in the modification and subsequent identification of cysteine residues by protein sequencing. We describe here simple on-sequencer procedures for alkylating cysteines in proteins which employ the reduction of cystines in proteins with tri-n-butylphosphine and concomitant alkylation of the resulting cysteines with 3-bromopropylamine. Addition of an aqueous acetone wash to a modified reaction cycle on the Applied Biosystems 477A sequencer removes excess 3-bromopropylamine.

Production and in vivo characterization of a bifunctional antibody (IVA039.1) with specificity for the mouse interleukin-2 receptor and vinca alkaloids.

The autoreactive T cell plays a pivotal role in the pathogenesis of type I diabetes in humans and in rodent animal models. Elimination or attenuation of these cells may provide a means to treat the disease. The use of antibodies directed to T cells has shown varying degrees of effectiveness in the treatment of autoimmune disease.

Quantitation of cysteine residues alkylated with 3-bromopropylamine by amino acid analysis.

A new versatile reagent, 3-bromopropylamine, for the quantitative analysis of cysteine residues in proteins and peptides is reported. When added to amino acid standards, the 3-bromopropylamine derivative of cysteine, S-3-aminopropylcysteine, elutes in a unique position on four different amino acid analysis systems without modification to their standard gradients. Optimized conditions for the complete alkylation of cysteines in proteins with 3-bromopropylamine are described.

How the anti-(metal chelate) antibody CHA255 is specific for the metal ion of its antigen: X-ray structures for two Fab'/hapten complexes with different metals in the chelate.

Antibodies with bound metal-chelate haptens provide new means for exploiting the diverse properties of metallic elements. The murine monoclonal antibody CHA255 (IgG1 lambda) binds the metal-chelate hapten indium (III)-4-[N'-(2-hydroxyethyl)thioureido]-L-benzyl-EDTA (designated In-EOTUBE) with high affinity (K(a) = 1.1 x 10(10) M-1).

Identification of cysteine residues alkylated with 3-bromopropylamine by protein sequence analysis.

A new reagent for the routine identification of cysteine residues during protein sequencing is described. This method employs 3-bromopropylamine to alkylate cysteines in proteins after reduction with dithiothreitol. Upon sequencing of the protein on an Applied Biosystems 477A protein sequencer, the aminopropylcysteine residue yields a phenylthiohydantoin (PTH) derivative which elutes reproducibly at a unique position immediately after PTH-leucine; baseline resolution is achieved without modification of the PTH analyzer gradient.

A COOH-terminal peptide confers regiospecific orientation and facilitates atomic force microscopy of an IgG1.

An antibody (IgG1) was designed for oriented adherence to a metal-containing surface. This was achieved by adding a metal-chelating peptide, (CP = His-Trp-His-His-His-Pro), to the COOH-terminus of the heavy chain through genetic engineering. Electroporation of the engineered heavy chain gene into cells expressing the complimentary light chain yielded colonies secreting an intact antibody containing the metal-chelating peptide (IgG1-CP) which had high affinity for a nickel-loaded iminodiacetate column.

Purification and characterization of a chimeric bifunctional antibody specific for human carcinoembryonic antigen and indium-benzyl-EDTA.

We describe the purification and characterization of a genetically engineered mouse/human chimeric bifunctional antibody specific for human carcinoembryonic antigen and indium-benzyl-EDTA. A clone expressing the bifunctional antibody has been previously described by our group and was found in this investigation also to express monospecific antibodies as well as Ig forms with mismatched light and heavy chains. The physicochemical properties of these various chimeric immunoglobulins were nearly identical.

Expression and characterization of a chimeric bifunctional antibody with therapeutic applications.

A simple method is described for the generation of a biologically produced mouse/human chimeric hetero-bifunctional antibody that has dual specificity for human carcinoembryonic Ag and metal chelate haptens. Two large compound chimeric vectors each containing the genetic information to produce a single antibody specificity were sequentially electroporated into the murine nonsecreting hybridoma SP2/0. This led to the isolation of a clone expressing high levels of total IgG (up to 25 micrograms/ml/10(6) cells), 10 to 20% of which showed simultaneous reactivity with both Ag.

Determination of the relative positions of amino acids by partial specific cleavages of end-labeled proteins.

We have developed a new method for obtaining information about protein sequences that uses an approach analogous to that used to determine DNA sequences. In essence, three steps are involved. First, a detectable label is attached exclusively to the amino terminus of a polypeptide.

Sequence homologies among E. coli ribosomal proteins: evidence for evolutionarily related groupings and internal duplications.

The complete or partial sequences of 47 E. coli ribosomal proteins described in the literature have been examined by computerized search and matching programs. In contrast to results previously reported by other investigators, sequence homologies were uncovered among some of these ribosomal proteins that are well beyond statistical expectations.