Biomedical subjects
S Pillai
Publications and source records attributed to S Pillai.
A radioimmunoprecipitation polyethylene glycol assay for circulating Entamoeba histolytica antigens.
Explore the source record for details and available documents.
A solid-phase sandwich radioimmunoassay for Entamoeba histolytica proteins and the detection of circulating antigens in amoebiasis.
A sensitive and specific immunochemical assay for Entamoeba histolytica antigens would be a valuable tool for clinical diagnosis, to study the sequelae of amoebiasis, and to screen for the expression of amoebic proteins in recombinant bacterial clones. The major impediment toward developing such an assay is the cross-reactivity of anti-E. histolytica antisera with a wide range of mammalian serum proteins. A rabbit anti-E. histolytica antiserum was repeatedly passed over three bovine serum protein immunoadsorbents and affinity purified over an E. histolytica protein-Sepharose 4B matrix. The purified antibody was radiolabeled and formed the upper layer of two specific and sensitive sandwich radioimmunoassays for amoebic proteins. One assay used a rabbit antiamoebic antibody solid phase and the other a human antibody solid phase. The latter assay proved capable of detecting amoebic antigens in the polyethylene glycol precipitates of sera from 21 of 21 patients with amoebiasis (and none of 22 control subjects).
Binding of ethylene diamine tetra acetate to erythrocyte cell membranes.
Explore the source record for details and available documents.
Detection and quantitation of immunoglobulins associated with tumours of the human oral cavity.
Explore the source record for details and available documents.
Can multiple low-density immunoadsorbents and 'negative' distance matrices help predict the three-dimensional structure of any globular protein?
Chemical cross-linking of a protein immobilized on multiple, site-specific, monoclonal, chemically modified antibody matrices combined with analysis of data on a distance matrix is likely to yield sufficient positive and 'negative' long-range distance information to help predict the three dimensional structure of any single-chain globular protein.
The binding of chondroitin 6-sulfate to plasma low density lipoprotein.
The interaction in vitro of several sulfated glycosaminoglycans with low density lipoproteins (LDL) has been studied. Chondroitin 6-sulfate and heparin were the only ones to produce turbidity when added to LDL in presence of Ca2+. However, when these two glycosaminoglycans were applied to LDL-affinity columns in presence of Ca2+, only chondroitin 6-sulfate was retained. Partially desulfated chondroitin 6-sulfate was not retained on LDL-affinity column, indicating the relevance of sulfate groups in the binding of LDL. Since chondroitin 4-sulfate and heparin, with a sulfate content respectively equal to and greater than that of chondroitin 6-sulfate, are not retained on LDL-affinity columns, the factors relevant to the binding of LDL are probably the conformation of the glycan in solution and the orientation of its sulfate groups.
Chemical cross-linking of a dimeric protein on a modified lectin matrix. A general probe for the chemical topology of oligomeric glycoproteins.
A dimeric glycoprotein, glucose oxidase, was allowed to react with lysine-specific cross-linkers, both when immobilized on a succinoylated lectin matrix at a critically low density and also at a high density in solution. Analysis of the cross-linked complexes thus obtained led to the following inferences with regard to the structure of this protein. (1) Of the 15 lysine residues on each glucose oxidase protomer, none is available on the non-interfacial surfaces. (2) Assuming that this protein possesses C2 symmetry with isologous bonding between subunits, it may be inferred that on each promoter there are at least two lysine clusters along or close to the interprotomeric interface. (3) These "interfacial' lysine residues on each protomer are so oriented that the epsilon-amino groups of lysine residues a and b on protomer 1 "face', and are very close to, the epsilon-amino groups of lysine residues b' and a' respectively on protomer 2. General inferences on the geometry of dimeric proteins derivable from an analysis of the cross-linked complexes obtained (as well as those not seen) by using this low-density matrix cross-linking approach were enumerated. Modified lectin matrices may prove useful in studying the three-dimensional structure of glycoproteins, particularly non-crystallizable oligomers.
Glycosaminoglycan composition of human oral cancer tissue.
Explore the source record for details and available documents.
A polyethylene glycol-based radioimmunoassay for gastrin.
Precipitation with polyethylene glycol 6000 is a satisfactory technique for "bound from free" separation in gastrin radioimmunoassay (RIA). This reagent, however, cannot be used in stoichiometric invertase-peptide conjugate-based enzyme immunoassays.
On the formation of N-nitrosopyrrolidine from potential precursors and nitrite.
Several naturally occurring amino compounds, structurally related to pyrrolidine, were reacted with nitrite in heated, weakly acidic, aqueous systems and the amount of NPYR formed was measured. The study included amines, free amino acids and different proline-containing peptides. The yields of NPYR formed from pyrrolidine, putrescine, agmatine, spermidine, spermine, proline, ornithine and arginine with nitrite in the pH range 6.6 to 4.0 were determined. The lowest yields were obtained from the amino acids, due to slow decarboxylation. When proline peptides were heated with nitrite at pH 5.7 and 4.0, no NPYR was detected (except in the case of cyclo-(Pro-Pro-)), but at pH 3.4, small amounts of NPYR were formed from all tested peptides. Cyclo-(Pro-Pro-) yielded NPYR at pH 5.7 and 4.0, as well. It is suggested that, under certain conditions, N-nitrosation may occur during cleavage of a peptide bond in the presence of nitrous acid. The formation of NPYR and NPIP from proline, pyrrolidine, putrescine, spermidine and cadaverine was studied in a model experiment, using minced bacon as the reaction medium. The results show that the formation of NPYR and other volatile nitrosamines is possible in the aqueous phase of bacon during frying.
Critical density for protein-protein monoconjugation on a polysaccharide matrix.
The galactose binding toxin (RCAII) from Ricinus communis was affinity-immobilised at varying densities on a polysaccharide matrix and reacted with glutaraldehyde. The critical density below which inter-molecular cross-links were not formed was determined. At this density RCAII was monoconjugated to lysozyme. This approach could serve as a prototype for enzyme-lectin and enzyme-antipolysaccharide antibody monoconjugation.
Affinity immobilisation and "negative" crosslinking: a probe for tertiary and quaternary protein structure.
Explore the source record for details and available documents.
Stoichiometric enzyme--peptide conjugation of an affinity matrix.
Explore the source record for details and available documents.
Monoconjugate enzyme linked immunoassay.
Explore the source record for details and available documents.
Protein-protein conjugation on a lectin matrix.
Explore the source record for details and available documents.
Type I persistent left fifth aortic arch with truncus arteriosus type A3: an unreported association.
Explore the source record for details and available documents.
Malignant oncocytoma of the nasal cavity: a case report.
Malignant oncocytoma is a rare clinical entity and is most commonly seen in the salivary glands. Its occurrence in the nasal cavity is extremely rare, and only 4 such cases have been reported in the literature. The authors report one such case in a 60-year-old woman, which presented as a slow-growing nasal mass arising from the nasal septum, with no lymph node metastasis, which was successfully managed by a combined modality of treatment-surgery followed by radiation therapy. The relevant literature has been reviewed. The case is discussed as a possible differential diagnosis for a mass in the nose.