Polymorphism of human salivary amylase

Summary Variation of human salivary amylase isoenzymes was investigated by isoelectric focusing on thin-layer polyacrylamide gel. Preliminary studies indicate a genetic polymorphism.     

A new insight into the phylogeny of vascular cryptogams with special reference to Selaginella and Isoetes inferred from nuclear ITS/5.8S rDNA sequences

In order to provide a better understanding of the evolutionary history of vascular cryptogams, phylogenetic framework was developed based on ITS1, ITS2 and 5.8S rDNA sequences of 102 extant taxa of vascular cryptogams using Maximum Parsimony (MP) analysis. The analysis revealed high GC content in Isoetaceae (60.5 %) in comparison with Selaginellaceae (54.4 %) that was envisaged to be the result of variation in selection, mutational bias, and biased recombination-associated DNA repair within these two plant lineages during evolution. Transition/transversion ratio was observed to be 0.9 in Isoetaceae, 0.68 in Selaginellaceae and 0.57 among all the 102 taxa belonging to lycophytes and ferns. It is hypothesized that the lycophytes have been separated very early during evolution and therefore acquired independent line of evolution from the other plant lineages. Although Selaginellaceae and Isoetaceae are closely related ancient plant groups, pairwise sequence divergence of sampled taxa on the basis of transition and transversion, and disparity index values per site between sampled sequence pairs pointed towards the differential investment of natural selection process. These lead to high rate of nucleotide substitution within nuclear genome of Selaginellaceae with respect to Isoetaceae. MP phylogenetic tree identified Isoetes subinermis, Isoetes durieui and Salvia microphylla as separate group among the studied taxa due to high sequence variation within these species through the time of evolution. Our result interpreted the polyphyletic origin of ferns and provides valuable information regarding the lycophytes and their fern allies.     

Agents that bind annexin A2 suppress ocular neovascularization

TM601 is a synthetic polypeptide with sequence derived from the venom of the scorpion Leiurus quinquestriatus that has anti‐neoplastic activity. It has recently been demonstrated to bind annexin A2 on cultured tumor and vascular endothelial cells and to suppress blood vessel growth on chick chorioallantoic membrane. In this study, we investigated the effects of TM601 in models of ocular neovascularization (NV). When administered by intraocular injection, intravenous injections, or periocular injections, TM601 significantly suppressed the development of choroidal NV at rupture sites in Bruch's membrane. Treatment of established choroidal NV with TM601 caused apoptosis of endothelial cells and regression of the NV. TM601 suppressed ischemia‐induced and vascular endothelial growth factor‐induced retinal NV and reduced excess vascular permeability induced by vascular endothelial growth factor. Immunostaining with an antibody directed against TM601 showed that after intraocular or periocular injection, TM601 selectively bound to choroidal or retinal NV and co‐localized with annexin A2, which is undetectable in normal retinal and choroidal vessels, but is upregulated in endothelial cells participating in choroidal or retinal NV. Intraocular injection of plasminogen or tissue plasminogen activator, which like TM601 bind to annexin A2, also suppressed retinal NV. This study supports the hypothesis that annexin A2 is an important target for treatment of neovascular diseases and suggests that TM601, through its interaction with annexin A2, causes suppression and regression of ocular NV and reduces vascular leakage and thus may provide a new treatment for blinding diseases such as neovascular age‐related macular degeneration and diabetic retinopathy. J. Cell. Physiol. 225: 855–864, 2010. © 2010 Wiley‐Liss, Inc.     

2-Amino-5-benzoyl-4-phenylthiazoles: Development of potent and selective adenosine A1 receptor antagonists

A series of 2-amino-5-benzoyl-4-phenylthiazole derivatives was investigated in radioligand binding studies at adenosine receptor (AdoR) subtypes with the goal to obtain potent and A₁-selective antagonists. Acylation of the 2-amino group was found to be crucial for high A₁ affinity. The best compound of the present series was 2-benzoylamino-5-p-methylbenzoyl-4-phenylthiazole (16m) showing a K_i value of 4.83 nM at rat and 57.4 nM at human A₁ receptors combined with high selectivity versus the other AdoR subtypes. The compound behaved as an antagonist in GTP shift assays at A₁ receptors. Compound 16m may serve as a new lead structure for the development of second-generation non-xanthine-derived A₁ antagonists which have potential as novel drugs.     

Pair wise binding affinity: 3D QSAR studies on a set of triazolo [1, 5-a] quinoxalines as antagonists of AMPA and KA receptors

The glutamate receptor system is implicated in the development and maintenance of epileptic seizures and it has been reported that compounds showing high affinity for both AMPA and KA binding sites are more potent anticonvulsants than compounds having selective affinity toward AMPA or KA receptor. These outcomes make such inhibitors future potential antiepileptic drugs. So, the pair wise binding affinity for AMPA and KA receptors inhibition was proposed by using the addition between biological activities of ligands. This approach for evaluation of pair wise binding affinity was exemplified using set of triazolo [1,5-a] quinoxaline for AMPA and KA receptors. The biological activity towards AMPA and KA receptors (expressed as -log IC_5O) was taken as a dependent variable for building CoMFA and CoMSIA models. The resulting models show the ways of increasing binding affinity to both AMPA and KA receptors as potential target for epilepsy. The statistically significant results show that pair wise CoMFA and CoMSIA models are better then individual models. The resulting cross-validated r²_CV value 0.806 for CoMFA is greater then 0.780 for CoMSIA pair wise model. The non-cross validated run giving a coefficient of determination r² value of 0.946 and 0.908 for CoMFA and CoMSIA respectively, provided a good correlation between the observed and computed affinities of the compounds.     

An international validation study of a Bhas 42 cell transformation assay for the prediction of chemical carcinogenicity

The Bhas 42 cell transformation assay is a sensitive short-term system for predicting chemical carcinogenicity. Bhas 42 cells were established from BALB/c 3T3 cells by the transfection of v-Ha-ras gene and postulated to have acquired an initiated state in the two-stage carcinogenesis theory. The Bhas 42 cell transformation assay is capable of detecting both tumor-initiating and tumor-promoting activities of chemical carcinogens. The full assay protocol consists of two components, the initiation assay and the promotion assay, to detect the initiating activity and the promoting activity, respectively. An international study was carried out to validate this cell transformation assay in which six laboratories from three countries participated. Twelve coded chemicals were examined in total and each chemical was tested by three laboratories. In the initiation assay, concordant results were obtained by three laboratories for eight out of ten chemicals and in the promotion assay, concordant results were achieved for ten of twelve chemicals. The positive results were obtained in all three laboratories with the following chemicals: 2-acetylaminofluorene was positive in both initiation and promotion assays; dibenz[a,h]anthracene was positive in the initiation assay; sodium arsenite, lithocholic acid, cadmium chloride, mezerein and methapyrilene hydrochloride were positive in the promotion assay. o-Toluidin hydrochloride was positive in the both assays in two of the three laboratories. d-Mannitol, caffeine and l-ascorbic acid were negative in both assays in all the laboratories, and anthracene was negative in both assays in two of the three laboratories except one laboratory obtaining positive result in the promotion assay. Consequently, the Bhas 42 cell transformation assay correctly discriminated all six carcinogens and two tumor promoters from four non-carcinogens. Thus, the present study demonstrated that the Bhas 42 cell transformation assay is transferable and reproducible between laboratories and applicable to the prediction of chemical carcinogenicity. In addition, by comparison of the present results with intra-laboratory data previously published, within-laboratory reproducibility using the Bhas 42 cell transformation assay was also confirmed.     

Oviposition Site-Selection by Bactrocera dorsalis Is Mediated through an Innate Recognition Template Tuned to γ-Octalactone

Innate recognition templates (IRTs) in insects are developed through many years of evolution. Here we investigated olfactory cues mediating oviposition behavior in the oriental fruit fly, Bactrocera dorsalis, and their role in triggering an IRT for oviposition site recognition. Behavioral assays with electrophysiologically active compounds from a preferred host, mango, revealed that one of the volatiles tested, γ-octalactone, had a powerful effect in eliciting oviposition by gravid B. dorsalis females. Electrophysiological responses were obtained and flies clearly differentiated between treated and untreated substrates over a wide range of concentrations of γ-octalactone. It triggered an innate response in flies, overriding inputs from other modalities required for oviposition site evaluation. A complex blend of mango volatiles not containing γ-octalactone elicited low levels of oviposition, whereas γ-octalactone alone elicited more oviposition response. Naïve flies with different rearing histories showed similar responses to γ-octalactone. Taken together, these results indicate that oviposition site selection in B. dorsalis is mediated through an IRT tuned to γ-octalactone. Our study provides empirical data on a cue underpinning innate behavior and may also find use in control operations against this invasive horticultural pest.     

Patient-Specific Metrics of Invasiveness Reveal Significant Prognostic Benefit of Resection in a Predictable Subset of Gliomas

Object

Malignant gliomas are incurable, primary brain neoplasms noted for their potential to extensively invade brain parenchyma. Current methods of clinical imaging do not elucidate the full extent of brain invasion, making it difficult to predict which, if any, patients are likely to benefit from gross total resection. Our goal was to apply a mathematical modeling approach to estimate the overall tumor invasiveness on a patient-by-patient basis and determine whether gross total resection would improve survival in patients with relatively less invasive gliomas.

Methods

In 243 patients presenting with contrast-enhancing gliomas, estimates of the relative invasiveness of each patient''s tumor, in terms of the ratio of net proliferation rate of the glioma cells to their net dispersal rate, were derived by applying a patient-specific mathematical model to routine pretreatment MR imaging. The effect of varying degrees of extent of resection on overall survival was assessed for cohorts of patients grouped by tumor invasiveness.

Results

We demonstrate that patients with more diffuse tumors showed no survival benefit (P = 0.532) from gross total resection over subtotal/biopsy, while those with nodular (less diffuse) tumors showed a significant benefit (P = 0.00142) with a striking median survival benefit of over eight months compared to sub-totally resected tumors in the same cohort (an 80% improvement in survival time for GTR only seen for nodular tumors).

Conclusions

These results suggest that our patient-specific, model-based estimates of tumor invasiveness have clinical utility in surgical decision making. Quantification of relative invasiveness assessed from routinely obtained pre-operative imaging provides a practical predictor of the benefit of gross total resection.