Cytotoxic and pro-apoptotic effects of Abrus precatorius L. on human metastatic breast cancer cell line, MDA-MB-231

Abrus precatorius is highly regarded as a universal panacea in the herbal medicine with diverse pharmacological activity spectra. This experimental study on the mechanism of the anticancer activity of A. precatorius leaf extracts, may offer new evidence for A. precatorius in the treatment of breast cancer in clinical practice. Cell death was determined by using MTT assay. Further analyses were carried out by doing DNA laddering, PARP cleavage, FACS, semi-quantitative RT-PCR and detection of cellular reactive oxygen species (ROS) by DCFDA assay. A. precatorius showed very striking inhibition on MDA-MB-231 cells. MTT assay showed more than 75 % inhibition of the cells and treated cells indicated visible laddering pattern with thick compact band. PARP cleavage produced 89 kDa cleavage product which was associated with apoptosis. Flow cytometer exhibited a sub-G0/G1 peak as an indicative of apoptosis. mRNA expression level of apoptosis-related genes p21 and p53 was markedly increased in cells treated with the extract as compared to control. The up-regulation of p21 and p53 may be the molecular mechanisms by which A. precatorius extract which induces apoptosis. An increase in the concentration of A. precatorius extract does not generate ROS, instead it reduces ROS formation in MDA-MB-231 cells, as evident from the shift in fluorescence below untreated control. This is the first report showing that A. precatorius leaf extract exhibits a growth inhibitory effect by induction of apoptosis in MDA-MB-231 cells. Our results contribute towards validation of the A. precatorius extract as a potentially effective chemopreventive or therapeutic agent against breast cancer.

Structural correlations in GexSe1-x glasses - a neutron diffraction study

Neutron diffraction measurement is carried out on GexSe1-x glasses, where 0.1 less than or equal to x less than or equal to 0.4, in a Q interval of 0.55-13.8 Angstrom(-1). The first sharp diffraction peak (FSDP) in the structure factor, S(Q), shows a systematic increase in the intensity and shifts to a lower Q with increasing Ge concentration. The coherence length of FSDP increases with x and becomes maximum for 0.33 less than or equal to x less than or equal to 0.4. The Monte-Carlo method, due to Soper, is used to generate S(Q) and also the pair correlation function, g(r). The generated S(Q) is in agreement with the experimental data for all x. Analysis of the first four peaks in the total correlation function, T(r), shows that the short range order in GeSe2 glass is due to Ge(Se-1/2)(4) tetrahedra, in agreement with earlier reports. Se-rich glasses contain Se-chains which are cross-linked with Ge(Se-1/2)(4) tetrahedra. Ge-2(Se-1/2)(6) molecular units are the basic structural units in Ge-rich, x = 0.4, glass. For x = 0.2, 0.33 and 0.4 there is evidence for some of the tetrahedra being in an edge-shared configuration. The number of edge-shared tetrahedra in these glasses increase with increasing Ge content.

Miniature cone tip resistance of sand with fly ash using triaxial setup

In a continuation of the authors' recent work, the ultimate tip resistance of a miniature cone using triaxial equipment was determined for samples of dry sand mixed with dry fly ash. The effect of (i) the proportion of fly ash, (ii) the relative density of samples, and (iii) the vertical overburden pressure was examined. It was noted that an addition of fly ash in sand for the same range of relative density leads to a significant reduction in the ultimate tip resistance of the cone (q(cu)). This occurs due to a decrease in the friction angle (phi) of the sample with an increase in the fly ash content for a given relative density. For phi greater than about 30 degrees, two widely used correlation curves from published literature, providing the relationships between q(cu) and phi for cohesionless soils, were found to provide satisfactory predictions, even for sand - fly ash mixtures. As was expected, the values of qcu increase continuously with an increase in the relative density of the soil mass and the vertical effective ( overburden) stress on the sample.

Structure of the Monosodium Salt of D-Glucose 6-Hydrogenphosphate

Na+.C6HI209 P-, Mr=282.1, monoclinic, e2~, a=5-762(1), b=7.163(2), c=12.313(1)A, fl= 99.97 (1) °, U= 500.5 A 3, Z= 2, D m = 1.86, D x = 1.87 Mg m -s, Cu Ka, 2 = 1.5418 A, /a = 3-3 mm -1, F(000) = 292, T= 300 K, final R for 922 observed reflections is 0-042. The phosphate ester bond, P-O(6), is 1.575 (5)A, slightly shorter than the P~O bond in monopotassium phosphoenolpyruvate [1.612 (6) A] [Hosur & Viswamitra (1981). Acta Cryst. B37, 839-843]. The pyranose sugar ring takes a 4C 1 chair conformation. The conformation about the exocyclic C(5)-C(6) bond is gauche-trans. The endocyclic C-O bonds in the glucose ring are nearly equal with C(5)-O(5) = 1.435 (8) and C(1)-O(5) = 1.436 (9) A. The sodium ion has seven near neighbours within a distance of 2.9 A. The crystal structure is stabilized by hydrogen bonds between the O atoms of symmetryrelated molecules.

He II spectra of La, Ce and Yb: Novel features in the valence band region

He II photoelectron spectra of La, Ce and Yb show features which cannot be explained in terms of single electron excitations. It is proposed that these are due to formation of electron-hole paris.

Synthesis and Reactions of Binuclear Diolefin Rhodium(I) Compounds bridged by Nitrogen Heterocycles, Crystal Structure of Dichloro-Di-1,5-Cyclooctadiene(Mu-Pyrazine)-Dirhodium(I) [[Rh(1,5-C8h12)Cl]2(Mu-C4h4n2)]

Binuclear complexes of rhodium(I) of the type [(dien)(X)Rh(μ-N-N)Rh(X)(dien)] (dien = 1,5-cyclooctadiene or norbornadiene; N-N = pyrazine, 4,4′-bipyridine or Phenazine and X = Cl or Br) with bridging heterocycles have been isolated and their reactions with carbon monoxide, 2,2′-bipyridine and 1,10-phenanthroline investigated. The crystal structure of [(COD)(Cl)Rh(μ-pyrazine)Rh(Cl)(COD)] has been determined.

EPR study on the role of Mn in enhancing PTC of BaTiO3

Low concentration of Mn (< 0.05 atom%) added to lanthanide-doped ceramics for enhancing the PTC effect did not show any EPR signal due to Mn in the tetragonal phase. Above Tc (400 K) it showed the six-line signal arising from Mn2+. This is explained on the basis of Mn existing as Mn3+ ion with short relaxation time at room temperature. Oxidation state changes to Mn2+ above Tc; thus Mn3+ acts as an electron trap. This augments the function of activated defect centres (VBa /ag VBa) in diminishing the charge carrier concentration across the phase transformation.

The structure of monopotassium phosphoenolpyruvate

CaH406P-.K +, M r = 206.10, is orthorhombic, space group Pbca (from systematic absences), a = 14.538(4), b = 13.364(5), c = 6.880 (6)A, U = 1383.9 A 3, D x = 2.07 Mg m -a, Z = 8, ~.(Mo Ka) = 0.7107/~, p(MO Ka) = 1.015 mm -1. The final R value is 0.042 for a total of 1397 reflections. The high energy P-O(13) and the enolic C(1)-O(13) bonds are 1.612 and 1.374 A respectively. The enolpyruvate moiety is essentially planar. The orientation of the phosphate with respect to the pyruvate group in PEP.K is distinctly different from that in the PEP-cyclohexylammonium salt, the torsion angle C (2)-C (1)-O(13)- P being -209.1 in the former and -90 ° in the latter. The K + ion binds simultaneously to both the phosphate and carboxyl ends of the same PEP molecule. The ester O(13) is also a binding site for the cation. The K + ion is coplanar with the pyruvate moiety and binds to 0(22) and O(13) almost along their lone-pair directions. The carbonyl 0(22) prefers to bind to the K + ion rather than take part in the formation of hydrogen bonds usually observed in carboxylic acid structures.

Structure of the disodium salt of glucose 1-phosphate hydrate, 2Na+.C6H11O9P2-.3.5H2O

Mr= 367.2, monoclinic, C2, a = 8.429 (1),b= 10.184(2), c= 16.570(2)A, /~= 99.18 (1) °, U= 1404.2 A 3, z = 4, D m = 1.73, D x = 1.74 Mg m -3,Cu K~, 2 = 1.5418 A, g = 2.99 mm -1, F(000) = 764,T= 300K, final R for 1524 observed reflections is0.069. The endocyclic C-O bonds in the glucose ring are nearly equal with C(5)-O(5)= 1.445 (10) and C(1)-O(5)= 1.424(10). The pyranose sugar ring adopts a 4C 1 chair conformation. The conformation about the exocyclic C(5)-C(6) bond is gauche-gauche, in contrast to gauche-trans observed in the structure of the dipotassium salt of glucose 1-phosphate. The phosphate ester bond, P-O(1), is 1.641 (6)A, slightly longer than the 'high-energy' P-,.O bond in the monopotassium salt of phosphoenolpyruvate [1.612 (6)A]. Two sodium ions are six coordinated while the third has only five neighbours.

Reaction of Hexachlorocyclotriphosphazene with Sodium p-Cresoxide

The reaction of hexachlorocyclotriphosphazene (N3P3Cl6) with sodium p-cresoxide proceeds by a predominantly nongeminal pathway. The presence of geminal isomers at the bis- and tris-stages of substitution in tiny quantities (< 5%) has also been observed. All the chloro(p-cresoxy)cyclotriphosphazenes and their dimethylamino derivatives have been characterized by 1H-, 13C{1H}-, and 31P{1H}-NMR spectroscopy. The reaction of N3P3Cl6 with sodium phenoxide has been reinvestigated. The relative yields of the products at various stages of substitution and their isomeric compositions are almost the same for both phenoxy and p-cresoxy systems. Possible mechanisms to explain the observed isomeric compositions are discussed. A through-space interaction involving oxygen-2p and phosphorus-3d orbitals is invoked to explain the greater yield of the cis isomer of N3P3Cl4(OAr)2 than that of its trans isomer.

Unsteady Self-similar Stagnation Point Boundary Layers for Micropolar Fluids

The self-similar solution of the unsteady laminar incompressible two-dimensional and axisymmetric stagnation point boundary layers for micropolar fluids governing the flow and heat transfer problem has been obtained when the free stream velocity and the square of the mass transfer vary inversely as a linear function of time. The nonlinear ordinary differential equations governing the flow have been solved numerically using a quasilinear finite-Difference scheme. The results indicate that the coupling parameter, mass transfer and unsteadiness in the free stream velocity strongly affect the skin friction, microrotation gradient and heat transfer whereas the effect of microrotation parameter is strong only on the microrotation gradient. The heat transfer is strongly dependent on the prandtl number whereas the skin friction gradient are unaffected by it.

Unsteady nonsimilar compressible laminar two-dimensional and axisymmetric boundary-layer flows

Unsteady nonsimilar laminar compressibletwo-dimensional and axisymmetric boundarylayer flows have been studied when external velocity varies arbitrarily with time and the flow is nonhomentropic. The governing nonlinear partial differential equations with three independent variables have been solved using an implicit finite difference scheme with quasilinearization technique from the origin to the point of zero skin-friction. The results have been obtained for (i) an accelerating stream and (ii) a fluctuating stream. The skin friction responds to the fluctuations in the free stream more compared to the heat transfer. It is observed that Mach number and hot wall cause the point of zero skin friction to occur earlier whereas cold wall delays it.

Specificity of deoxycytidylate antibodies

Antibodies to deoxycytidylate (dpC) were elicited in rabbits using a thyroglobulin (Tg) conjugate of dpC. The specificity of the antibodies was determined by measuring the inhibition of the binding of [3H]dpC to the antibodies by various non-radioactive nucleotides or derivatives. The antibodies were found to distinguish dpC from pC and DNA from RNA, probably due to their specificity for the conformation of the deoxycytidylate.