Cytotoxicity and mode of action of vanada- and niobatricarbadecaboranyl monohalide complexes in human HL-60 promyelocytic leukemia cells

Vanada- and niobatricarbadecaboranyl monohalide complexes proved to be potent cytotoxic agents against murine and human leukemia and lymphoma growth as well as HeLa suspended uterine carcinoma. The vanada complex reduced the growth of KB nasopharynx, Hepe liver, HCT-8 ileum and 1-A9 ovary solid carcinomas. A mode of action study in human HL-60 promyelocytic leukemia cells showed that DNA and purine de novo syntheses were significantly inhibited with suppression of the regulatory enzymes activities of DNA polymerase alpha and PRPP-amido transferase. There was moderate inhibition of RNA synthesis and m-RNA polymerase activity. These complexes did not inhibit human topoisomerase I or II activity, although the niobium complex nicked the DNA. The complexes did activate caspases 3, 6 and 9 which are linked to apoptosis programmed cell death. These vanada- and niobatricarbadecaboranyl monohalide complexes appear to be more specific in their effects on leukemia cell metabolism than other sandwich complexes which have broad effects on multiple enzymes.     

Inapparent twin malignancy in thyroglossal cyst: Case Report

BACKGROUND: Although malignancy has been reported in thyroglossal cysts, synchronous occurrence of two malignancies is extremely rare. CASE REPORT: A case of concurrent papillary and squamous carcinoma arising in the thyroglossal cyst is presented here. CONCLUSIONS: Papillary and squamous carcinoma simultaneously occurring in a thyroglossal cyst is rarely diagnosed prior to surgery and pose a therapeutic dilemma. In view of the extreme rarity of the condition, controversies do exist regarding the optimal strategy to be adopted. The ideal procedure needs to be individually tailored and involve a combination of surgery, radio ablation, thyroid suppression and external radiotherapy.     

Structural studies on LNA quadruplexes

LNAs (locked nucleic acids) are new DNA analogues with higher binding affinities toward nucleic acids than the canonical counterparts mainly due to the characteristic conformational restriction arising from the 2'-O, 4'-C methylene bridge. In light of the promising therapeutic applications and considering the advantageous characteristics of LNAs, such as their high water solubility, easy handling, and synthetic accessibility through the conventional phosphoramidite chemistry, we undertook a study concerning the capability of these nucleic acid analogues to form quadruplex structures. Particularly, we have been investigating the LNA/DNA chimeras corresponding to the well-known DNA sequences 5-GGTTGGTGTGGTTGG-3', capable of forming an unimolecular quadruplex. This article deals with the study of the sequence 5'-ggTTggTGTggTTgg-3' (upper and lower case letters represent DNA and LNA residues, respectively), which, according to CD spectroscopy, is able to fold into a quadruplex structure.     

Improvement of nutritive value of grass pea (Lathyrus sativus) seed meal in the formulated diets for rohu, Labeo rohita (Hamilton) fingerlings after fermentation with a fish gut bacterium

Eight isonitrogenous (35% crude protein approximately) and isocaloric (4.0 kcalg(-1) approximately) diets were formulated incorporating raw and fermented grass pea (Lathyrus sativus) seed meal at 10%, 20%, 30% and 40% levels by weight into a fish meal based diet and fed to rohu, Labeo rohita, fingerlings for 80 days and fish performance was studied. A particular bacterial strain (Bacillus sp.) isolated from the intestine of adult common carp (Cyprinus carpio) reared in the wild having significant amylolytic, cellulolytic, lipolytic and proteolytic activities were used for fermentation of seed meal for 15 days at 37 degrees C. Fermentation of grass pea seed meal was effective in significantly reducing the crude fibre content and anti-nutritional factors, such as tannins, phytic acid and the neurotoxin, beta-ODAP and enhancing the available free amino acids and fatty acids. In terms of growth response, feed conversion ratio and protein efficiency ratio, 30% fermented grass pea seed meal incorporated diet resulted in significantly (P < 0.05) better performance of rohu fingerlings. In general, growth and feed utilization efficiencies of fish fed diets containing fermented seed meal were superior to those fed diets containing raw seed meal. The apparent protein digestibility (APD) values decreased with increasing levels of raw seed meal in the diets. The APD for raw seed meal was lower at all levels of inclusion in comparison to those for the fermented seed meals. The highest deposition of carcass protein was recorded in fish fed the diet containing 40% fermented seed meal. The results indicated that fermented grass pea seed meal can be incorporated in carp diets up to 30% level compared to 10% level of raw seed meal.     

Design, synthesis and evaluation of carbazole derivatives as PPAR alpha/gamma dual agonists and antioxidants

A series of hydroxycarbazole derivatives were synthesized and evaluated for PPAR alpha/gamma dual agonist as well as antioxidant activities. While most compounds showed good antioxidant activity, some compounds were identified as potential PPAR alpha/gamma dual agonists as well. Compounds 10a and 16 were found to be active in animal studies.     

TEDOR with adiabatic inversion pulses: Resonance assignments of <Superscript>13</Superscript>C/<Superscript>15</Superscript>N labelled RNAs

We have examined via numerical simulations the performance characteristics of different 15N RF pulse schemes employed in the transferred echo double resonance (TEDOR) experimental protocol for generating 13C-15N dipolar chemical shift correlation spectra of isotopically labelled biological systems at moderate MAS frequencies (omega(r) approximately 10 kHz). With an 15N field strength of approximately 30-35 kHz that is typically available in 5 mm triple resonance MAS NMR probes, it is shown that a robust TEDOR sequence with significant tolerance to experimental imperfections sa as H1 inhomogeneity and resonance offsets can be effectively implemented using adiabatic heteronuclear dipolar recoupling pulse schemes. TEDOR-based 15N-13C and 15N-13C-13C chemical shift correlation experiments were carried out for obtaining 13C and 15N resonance assignments of an RNA composed of 97 (CUG) repeats which has been implicated in the neuromuscular disease myotonic dystrophy.     

SPAAN: a software program for prediction of adhesins and adhesin-like proteins using neural networks

MOTIVATION: The adhesion of microbial pathogens to host cells is mediated by adhesins. Experimental methods used for characterizing adhesins are time-consuming and demand large resources. The availability of specialized software can rapidly aid experimenters in simplifying this problem. We have employed 105 compositional properties and artificial neural networks to develop SPAAN, which predicts the probability of a protein being an adhesin (Pad). RESULTS: SPAAN had optimal sensitivity of 89% and specificity of 100% on a defined test set and could identify 97.4% of known adhesins at high Pad value from a wide range of bacteria. Furthermore, SPAAN facilitated improved annotation of several proteins as adhesins. Novel adhesins were identified in 17 pathogenic organisms causing diseases in humans and plants. In the severe acute respiratory syndrome (SARS) associated human corona virus, the spike glycoprotein and nsps (nsp2, nsp5, nsp6 and nsp7) were identified as having adhesin-like characteristics. These results offer new lead for rapid experimental testing. AVAILABILITY: SPAAN is freely available through ftp://203.195.151.45 CONTACT: ramu@igib.res.in.     

Lipid peroxidation and antioxidant status in patients with periodontitis

Our aim was to assess the degree of oxidative stress in patients with periodontitis by measuring their levels of thiobarbituric acid reactive substances (TBARS), enzymatic antioxidants (superoxide dismutase (SOD), catalase (CAT), glutathione peroxide (GSHPx)), and non-enzymatic antioxidants (vitamins E and C, reduced glutathione (GSH)). This study was conducted on 25 adult chronic periodontitis sufferers who were patients in Rajah Muthiah Dental College and Hospital, Annamalai University. The levels of TBARS and non-enzymatic antioxidants, and the activities of enzymatic antioxidants in the patients' plasma, erythrocytes and gingival tissues were assayed using specific colorimetric methods. The periodontitis sufferers had a significantly higher TBARS level than the healthy subjects. In the plasma, erythrocytes, erythrocyte membranes and gingival tissues of the periodontitis sufferers, enzymatic antioxidant activities were found to be significantly higher, whereas the levels of non-enzymatic antioxidants were significantly lower (except for reduced glutathione in the gingival tissues) relative to the parameters found for healthy subjects. The disturbance in the endogenous antioxidant defense system due to over-production of lipid peroxidation products at inflammatory sites can be related to a higher level of oxidative stress in patients with periodontitis.     

Novel caged fluorescein diphosphates as photoactivatable substrates for protein tyrosine phosphatases

We have characterized some novel caged fluorescein diphosphates as photoactivatable, cell-permeable substrates for protein tyrosine phosphatases and explored their usefulness in identifying inhibitors of tyrosine phosphatases. 1-(2-Nitrophenyl)ethyl protected fluorescein diphosphate (NPE-FDP) undergoes rapid photolysis to release FDP upon irradiation with a 450-W UV immersion lamp and its by-product does not inactivate protein tyrosine phosphatase 1B (PTP1B) or alters the viability of cells. The generated FDP from photolysis of NPE-FDP was shown to have exactly the same properties as FDP, which can be used as a PTP substrate in pure enzyme assays. We have also demonstrated that the PTP activity can be measured using NPE-FDP in small droplets. Its advantage as an inert substrate before photolysis allows the possibility of applying nanospray technology in screening and optimizing PTP inhibitors through a large chemical library. Like other caged bioeffectors such as nucleotide and inositol trisphosphate, NPE-FDP is cell-permeable. The NPE-FDP can be photolyzed to generate FDP inside cells, and then can be hydrolyzed by phosphatases to produce fluorescein monophosphate and subsequently to fluorescein. Although Jurkat cells contain high concentrations of CD45, it has not been possible to use FDP as a substrate to measure CD45 activity in the intact cell. This is due to the hydrolysis of FDP by several other cellular phosphatases. However, NPE-FDP can be useful as a cell-permeable substrate for overexpressed phosphatases such as alkaline phosphatase.     

Dynamic change of neural cell adhesion molecule polysialylation on human neuroblastoma (IMR-32) and rat pheochromocytoma (PC-12) cells during growth and differentiation

Polysialic acid (PSA) is a regulatory epitope of neural cell adhesion molecule (NCAM) in homophilic adhesion of neural cells mediated by NCAM, is also known to be re-expressed in several human tumors, thus serves as an oncodevelopmental antigen. In this study, using a recently developed ultrasensitive chemical method in addition to immunochemical methods, growth stage-dependent and retinoic acid (RA)-induced differentiation-dependent changes of PSA expression in human neuroblastoma (IMR-32) and rat pheochromocytoma (PC-12) cells were analyzed both qualitatively and quantitatively. Both IMR-32 and PC-12 cells expressed PSA on NCAM, and the level of PSA expressed per unit weight of cells increased with post-inoculation incubation time. The most prominent feature was seen at the full confluence stage. RA induced neuronal differentiation in both IMR-32 and CP-12 cells that paralleled the change in the PSA level. Chemical analysis revealed the presence of NCAM glycoforms differing in the degree of polymerization (DP) of oligo/polysialyl chains, whose DP was smaller than 40. DP distribution of PSA was different between the cell lines and was changed by the growth stage and the RA treatment. Thus DP analysis of PSA is important in understanding both mechanism and biological significance of its regulated expression.