Genetic and structural polymorphism of complement receptor 1 in normal Indian subjects.

The human complement receptor 1 (C3b/C4b receptor, CD35, CR1), a polymorphic membrane bound glycoprotein, is differentially expressed on erythrocytes, eosinophils, monocytes, B and T-lymphocytes, dendritic cells and kidney podocytes. It also occurs in the plasma as soluble CR1 (sCR1) and in urine as urinary CR1 (uCR1). Different population studies have suggested the functional and physiological significance of the structural (CR1-A/190, CR1-B/220, CR1-C/160 and CR1-D/250 kDa) and genomic (HH, high erythrocyte CR1 expression, HL, intermediate and LL, low expression) polymorphisms in health and disease. However, simultaneous study on the structural and genomic polymorphism in the same group of study subjects is lacking. This is the first study on both quantitative and structural polymorphism in 101 healthy volunteers from different parts of India by random sampling. In our study, AA phenotype was found to be expressed in 84.2% of individuals and 14.8% carried AB phenotype. One individual (0.9%) was found to possess BB phenotype. Homozygous BB pattern was identified for the first time in Indian subjects. The relative gene frequencies for A and B allele were found to be 0.916 and 0.084, respectively. Pertaining to quantitative polymorphism, percentage distribution for HH, HL and LL phenotypes was found to be 23.7, 54.45 and 21.79%, respectively and the gene frequencies were 0.51 and 0.49 for H and L allele, respectively. The observations for quantitative as well as structural polymorphism showed a good probability of fitness with Hardy-Weinberg equilibrium, thus proving that both the types of CR1 polymorphic forms are encoded by autosomal co-dominant alleles. We found a higher frequency of HL and AA phenotypes in the study subjects. Our findings are unique as we found that gene frequencies for structural and quantitative polymorphism in our study subjects were a combination of those found in Caucasian and Oriental populations.

Flavones as analytical reagents-a review.

A review is given of the use of flavones as spectrophotometric, fluorimetric and gravimetric reagents for metals and a few non-metals.

Analytical reactions of hydroxyflavones.

Newer analytical aspects of the chemistry of hydroxyflavone compounds are reviewed.

Analytical applications of hydrazones.

A review of the analytical applications of hydrazones is presented.

Analytical applications of hydroxycoumarins.

A review is presented of the analytical potentialities and physico-chemical properties of hydroxycoumarins.

Metal complexation with 2-hydroxy-6-methylpyridine-3-carboxylic acid.

Metal complexation with 2-hydroxy-6-methylpyridine-3-carboxylic acid has been studied. The ligand finds use in detection and determination of iron (III). The order of stability constants of the bivalent transition metal complexes is Cu > Zn > Fe > Ni > Co > Mn. b]|de|Die Komplexbildung von Metallen mit 2-Hydroxy-6-methylpyridin-3-carbonsäure wurde untersucht. Der Ligand findet Verwendung beim Nachweis und bei der Bestimmung von Eisen(III). Die Reihenfolge der Stabilitätskonstanten der Komplexe mit zweiwertigen Uberg angsmetallen ist Cu > Zn > Fe > Ni > Co > Mn.

Iron (III) complexation with 2,3-pyridinediol.

Iron(III) complexation with 2,3-pyridinediol has been investigated with a view to ascertaining the structures of the complexes formed and examining the analytical potential of this biochemically important ligand.

Spectrophotometric determination of cobalt with phenanthrenequinone monoxime.

Phenanthrenequinone monoxime reacts with cobalt to form a yellow-orange insoluble 1:3 (cobalt:ligand) complex which is extractable into chloroform in the pH range 4.45-8.0. The determination of cobalt is carried out at 470 mmu. Beer's law is obeyed over the concentration range 0-3.0 ppm of cobalt. The sensitivity is 0-00336 mug of Co/cm(2) for 0.001 absorbance. The effect of a number of foreign ions has been studied.

Sensitive tests for nitrite through azo-dye formation.

The diazonium cation resulting from the interaction of nitrite with sulphanilic acid is coupled with pyridinols to give red azo-dyes. Compared to many other colour reactions employed for detection of nitrite, the present systems afford greater sensitivity. Many ions do not affect the colour; thus detection and determination are selective. The method is applied in determination of nitrite in water samples.

Electrochemical studies of p-nitroaniline-formaldehyde polymer.

p-Nitroaniline-formaldehyde polymer has been prepared and separated into three fractions by fractional precipitation. The fractions and the conglomerate have been titrated in non-aqueous medium both potentiometrically and conductometrically. The inflections and breaks in the titration curves have been correlated with the degree of polymerization and the structure of the polymer.

Complexation reactions of pyridinols.

Complexation of iron(III) with several pyridinols has been studied and used in selective detection and determination (spectrophotometric and chelatometric) of the metal. Iron(III)-pyridinol complexes are also used as indicators in acid-base titrations. A thiol group vicinal to a phenol group in a pyridine molecule provides a reagent that is a suitable ligand for palladium(II) determination. Stability constants of bivalent metal complexes with pyridinols have been determined potentiometrically.

Metal complexes with tropolones.

A review of the analytical applications of tropolone and its derivatives.

Determination of nickel by flame atomic-absorption spectrophotometry after separation by adsorption of its nioxime complex on microcrystalline naphthalene.

A method has been developed for the determination of nickel in alloys by flame atomic-absorption spectrophotometry after formation of a water-insoluble complex, its adsorption on microcrystalline naphthalene, and dissolution of the complex and naphthalene in nitric acid and xylene.

Selective pyrimidinethiols for palladium(II) determination.

Alkyl and aryl substituted 4, 4, 6-trimethyl-(1H, 4H)2-pyrimidinethiols react selectively with palladium(II) in strong acids, forming yellow complexes (lambda(max) 430 nm) extractable into non-polar solvents. By an extractive spectrophotometric procedure, microgram amounts of palladium may be determined in the presence of milligram amounts of many species, including all the other platinum-group metals.

Selective complexation of palladium and osmium with substituted pyrimidinethiols.

1-Amino-, 1-anilino- and 1-(2',4'-dinitroanilino)-4,4,6-trimethyl-1H,4H-2-pyrimidinethiols react with Pd(II) and Os(VIII), forming coloured complexes extractable into non-polar organic solvents. The optimum conditions for the complexation have been established. Beer's law is obeyed and by an extractive spectrophotometric procedure, microgram quantities of the two metals are determined in the presence of large amounts of diverse ions, including all the other metals of the iron and platinum groups.

Phenanthraquinone monothiosemicarbazone as indicator for chelatometric determinations.

A new compound, phenanthraquinone monothiosemicarbazone, is satisfactorily used in the chelatometric determination of copper(II), zinc(II), cadmium(II), mercury(II) and nickel(II). The method is applied in the analysis of various alloys.

Analytical reactions of substituted pyrimidines.

Analytical aspects of the chemistry of substituted pyrimidines are reviewed.

Spectrophotometric determination of copper in environmental samples by solid-liquid extraction of its 9, 10-phenanthrenequinone monoximate complex into molten naphthalene.

A fairly selective and sensitive spectrophotometric method has been developed for determination of copper after extraction of its 9, 10-phenanthrenequinone monoximate complex into molten naphthalene in the pH range of 6.1-8.4. At room temperature, the solid naphthalene containing the metal complex is separated by filtration, dissolved in dimethylformamide (DMF) and the absorbance measured at 470 nm against the reagent blank. Beer's law is obeyed in the concentration range, 0.0-9.6 micrograms of copper in 10ml of DMF. The molar absorptivity and sensitivity are 6.30 X 10(4) 1 mol-1 cm-1 and 0.001 micrograms cm-2, respectively. The interference of various ions has been studied and the method has been applied for the determination of copper in various standard reference materials, beers, wines, human hair and environmental samples.