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Biomedical subjects

R Vijayalakshmi

Publications and source records attributed to R Vijayalakshmi.

10 recordsLinked to original sources
PubMed2005

Color Doppler flow pattern in antenatal diagnosis of unguarded tricuspid valve.

We describe an antenatally diagnosed case of unguarded tricuspid valve in a 15-week fetus. Because of its rarity, the differentiation of this anomaly from other tricuspid valve dysplasias is difficult. Tricuspid regurgitation is the hallmark of Ebstein's anomaly and other tricuspid valve abnormalities, whereas in unguarded tricuspid orifice there is total absence of the valve, resulting in 'to and fro' flow across the right-sided chambers. The color Doppler flow pattern helps in differentiating this anomaly from others. The antenatal diagnosis was confirmed on autopsy.

Adult↗
PubMed2002

A study of the interaction of Cr(III) complexes and their selective binding with B-DNA: a molecular modeling approach.

Molecular modeling and energy minimisation calculations have been used to investigate the interaction of chromium(III) complexes in different ligand environments with various sequences of B-DNA. The complexes are [Cr(salen)(H(2)O)(2)](+); salen denotes 1, 2 bis-salicylideneaminoethane, [Cr(salprn)(H(2)O)(2)](+); salprn denotes 1, 3 bis- salicylideneaminopropane, [Cr(phen)(3)](3+); phen denotes 1, 10 phenanthroline and [Cr(en)(3)](3+); en denotes ethylenediamine. All the chromium(III) complexes are interacted with the minor groove and major groove of d(AT)(12), d(CGCGAATTCGCG)(2) and d(GC)(12) sequences of DNA. The binding energy and hydrogen bond parameters of DNA-Cr complex adduct in both the groove have been determined using molecular mechanics approach. The binding energy and formation of hydrogen bonds between chromium(III) complex and DNA has shown that all complexes of chromium(III) prefer minor groove interaction as the favourable binding mode.

Binding Sites↗
PubMed2000

Interaction of DNA with [Cr(Schiff base)(H(2)O)(2)]ClO(4).

The binding of Schiff base complexes of chromium(III) of the type [Cr(salen)(H(2)O)(2)](+) and [Cr(salprn)(H(2)O)(2)](+), where salen denotes 1,2-bis(salicylideneamino)ethane and salprn denotes 1,3-bis(salicylideneamino)propane to calf thymus DNA has been investigated by absorption, emission, circular dichroism, melting temperature and viscosity measurements. These chromium(III) complexes showed absorption hyperchromicity accompanied by red shift in charge transfer band, fluorescence enhancement, increase in melting temperature, some structural changes in CD spectra and changes in specific viscosity when bound to calf thymus DNA. The binding constant K(b) has been determined from absorption measurements for both the complexes and found to be (2.5+/-0. 4)x10(3) M(-1) for [Cr(salen)(H(2)O)(2)](+) and (1.7+/-0.3)x10(4) M(-1) for [Cr(salprn)(H(2)O)(2)](+). From the binding stoichiometry of DNA-[Cr(salprn)(H(2)O)(2)](+), the number of binding site size has been determined and found to be ten base pairs per bound complex molecule. The chromium(III) complexes also bring about single strand cleavage in plasmid DNA. The experimental results show that the chromium(III) complexes bind to DNA by non-intercalative mode. Major groove binding is the preferred mode of interaction for these Schiff base complexes of chromium(III).

Binding Sites↗
PubMed2000

DNA cleavage by a Chromium(III) complex.

A new Cr(III) complex with the empirical formula [Cr(Schiff base) (H(2)O)(2)]ClO(4), where the Schiff base is 2, 3-bis¿[(2-hydroxy-4-diethylamino) (phenyl) (methylene)]amino¿2-butenedinitrile has been synthesized and characterized spectroscopically. Binding of this complex to DNA has been studied using UV-visible spectroscopy. The complex has been found to bind to the major groove of DNA with a binding constant, K = (1.3 +/- 0.2) x 10(3) M(-1). The induced CD spectrum of the complex in the presence of DNA is also indicative of major groove binding. Gel electrophoresis of plasmid DNA in the presence of the complex shows that the complex brings about nicking of the DNA.

Chromium Compounds↗
PubMed1999

Chromium(III) interactions with nucleosides and nucleotides: a mass spectrometric study.

Interactions of [Cr(salprn)(H(2)O)(2)]ClO(4) with nucleosides and dinucleotides were studied using electrospray ionization mass spectrometry. The nucleosides 2'-deoxycytidine, thymidine, 2'-deoxyadenosine, 2'-deoxyguanosine, cytidine, adenosine and guanosine form 1 : 1 and 2 : 1 adducts with [Cr(salprn)](+), whereas the dinucleotides CpG, GpC, ApT, TpA and TpC form only the 1 : 1 adducts. Collisional activation (CA) spectra of these adducts reveal that Cr(+) attaches to the bases in nucleosides and to both the phosphate and base, especially cytosine and guanine moieties, in the nucleotides. The sugar residues appear to offer no binding sites as elimination of sugar residues is fairly abundant in the CA spectra of the adducts of many of the nucleosides.

Chromium Compounds↗
PubMed1988

Reduced anaerobic glycolysis in oral contraceptive users.

Oral contraceptives containing combinations of estrogens and progestogens are known to impair glucose tolerance. The biochemical mechanisms underlying this lesion are speculative. In the present study women treated with OC for periods exceeding 10 cycles showed significant reduction in the activity of the key glycolytic enzyme phosphofructokinase (40%) and the levels of lactate (42%) in the erythrocytes compared to controls. These observations in women are analogous to those made earlier in female rats.

Adult↗
PubMedDate not supplied

Nanotechnology in dentistry.

Nanotechnology is manipulating matter at nanometer level and the application of the same to medicine is called nanomedicine. Nanotechnology holds promise for advanced diagnostics, targeted drug delivery, and biosensors. In the long-term, medical nanorobots will allow instant pathogen diagnosis and extermination, individual cell surgery in vivo, and improvement of natural physiological function. Current research is focusing on fabrication of nanostructures, nanoactuators, and nanomotors, along with means to assemble them into larger systems, economically and in great numbers.

Dental Materials↗