Lymphokine synthesis is induced in human thymocytes by activation of the CD 2 (T11) pathway

This study shows that unfractionated thymocytes can be activated to proliferate in response to activation by the CD 2 pathway, to express interleukin 2 receptors, and to synthesize interleukin 2 and interferon-gamma. Less mature, T3- thymocytes, isolated by negative selection are activated to a lesser extent than are unfractionated thymocytes; activation by the CD 2 pathway, induces proliferation, the expression of the interleukin 2 gene and interferon-gamma synthesis. 12-O-Tetradecanoyl phorbol 13-acetate in combination with the anti-CD 2 antibodies T11(2) + T11(3) increases the response of both unfractionated and T3- thymocytes. In addition we demonstrate that tetradecanoyl phorbol acetate in combination with T11(3) can replace the requirement for T11(2) for thymocyte activation and induce the expression of T11(3).     

Additive effects of metal excess and superoxide,a highly toxic mixture in bacteria

Heavy metal contamination is a serious environmental problem. Understanding the toxicity mechanisms may allow to lower concentration of metals in the metal-based antimicrobial treatments of crops, and reduce metal content in soil and groundwater. Here, we investigate the interplay between metal efflux systems and the superoxide dismutase (SOD) in the purple bacterium Rubrivivax gelatinosus and other bacteria through analysis of the impact of metal accumulation. Exposure of the Cd²⁺-efflux mutant ΔcadA to Cd²⁺ caused an increase in the amount and activity of the cytosolic Fe-Sod SodB, thereby suggesting a role of SodB in the protection against Cd²⁺. In support of this conclusion, inactivation of sodB gene in the ΔcadA cells alleviated detoxification of superoxide and enhanced Cd²⁺ toxicity. Similar findings were described in the Cu⁺-efflux mutant with Cu⁺. Induction of the Mn-Sod or Fe-Sod in response to metals in other bacteria, including Escherichia coli, Pseudomonas aeruginosa, Pseudomonas putida, Vibrio cholera and Bacillus subtilis, was also shown. Both excess Cd²⁺ or Cu⁺ and superoxide can damage [4Fe-4S] clusters. The additive effect of metal and superoxide on the [4Fe-4S] could therefore explain the hypersensitive phenotype in mutants lacking SOD and the efflux ATPase. These findings underscore that ROS defence system becomes decisive for bacterial survival under metal excess.     

Design and molecular modeling of novel P38α MAPK inhibitors targeting breast cancer,synthesized from oxygen heterocyclic natural compounds

Two new series of furochromone and benzofuran derivatives were designed, synthesized and evaluated for their in vitro anticancer activity against MCF-7 and MDA231 breast cancer cell lines. Compounds 5, 6, 7, 9, 15a, 16, 17a and 18 exhibited the best antiproliferative activities with IC₅₀ values ranging from 1.19 to 2.78?µM against MCF-7 superior to lapatinib as reference standard (IC₅₀; 4.69?µM). Compounds 15a and 18 revealed significant cytotoxic activity against MCF-7 and MDA231, therefore their inhibitory potencies against p38α MAP kinase were evaluated. Remarkably they exhibited significant IC₅₀ of 0.04?µM comparable to SB203580 (IC₅₀; 0.50?µM) as a reference standard. These promising results of cytotoxic activity and significant inhibition of p38α MAP kinase, were confirmed by exploring the effect of benzofuran derivative (18) on the apoptotic induction and cell cycle progression of MCF-7 cell line. Compound 18 induced preG1 apoptosis and cell growth arrest at G2/M phase preventing the mitotic cycle. Moreover it activated the caspase-7 which executes apoptosis. Molecular docking study was carried out using GOLD program to predict the mode of binding interaction of the synthesized compounds into the target p38α MAPK. Additionally, the physicochemical properties and ADME parameters of compound 18 were examined in silico to investigate its drug-likeness.     

Protective and therapeutic effects of Argyreia speciosa against ethanol-induced gastric ulcer in rats

The protective and therapeutic effects of Argyreia speciosa Sweet (Convolvulaceae) against ethanol-induced gastric ulcer in rats were evaluated. Ethanolic and water extracts of the aerial plant parts (200 mg/kg body weight) were orally administered daily for seven days prior to or after ulceration with one oral dose of 1 mL absolute ethanol on 24-h empty stomachs. Rats were divided into eleven groups. Group 1 served as control. To groups 2 and 3 each extract was administered. Groups 4 to 6 received each extract or ranitidine (100 mg/kg body weight) prior to ulcer induction. Groups 7 to 9 received each extract or ranitidine post ulcer induction. Groups 10 and 11 were gastric ulcerative rats after one hour and one week of ethanol induction. The evaluation was done through measuring ulcer indices: stomach acidity and volume, lesion counts, mucus, and prostaglandin E2 contents. Oxidative stress marker, i. e. malondialdehyde, glutathione, and superoxide dismutase, were estimated. Certain marker enzymes for different cell organelles, i. e. succinate and lactate dehydrogenases, glucose-6-phosphatase, acid phosphatase, and 5'-nucleotidase, were evaluated. The work was extended to determine the collagen content and the histopathological assessment of the stomach. Gastric ulcer exhibited a significant elevation of the ulcer index, antioxidant levels, collagen content, and the marker enzymes. The water extract attenuated these increments and was more potent as a protective agent, while the ethanol extract exhibited stronger therapeutic potency. In conclusion, A. speciosa acted as antiulcer agent. More detailed studies are required to identify the compounds responsible for the pharmacological effect.     

Synthesis and activity of azaterphenyl diamidines against Trypanosoma brucei rhodesiense and Plasmodium falciparum

A series of azaterphenyl diamidines has been synthesized and evaluated for in vitro antiprotozoal activity against both Trypanosoma brucei rhodesiense (T. b. r.) and Plasmodium falciparum (P. f.) and in vivo efficacy in the STIB900 acute mouse model for T. b. r. Six of the 13 compounds showed IC₅₀ values less than 7 nM against T. b. r. Twelve of those exhibited IC₅₀ values less than 6 nM against P. f. and six of those showed IC₅₀ values 0.6 nM, which are more than 25-fold as potent as furamidine. Moreover, two of them showed more than 40-fold selectivity for P. f. versus T. b. r. Three compounds 15b, 19d and 19e exhibited in vivo efficacy against T. b. r. much superior to furamidine, and equivalent to or better than azafuramidine. The antiparasitic activity of these diamidines depends on the ring nitrogen atom(s) location relative to the amidine groups and generally correlates with DNA binding affinity.     

Two HIV-1 Variants Resistant to Small Molecule CCR5 Inhibitors Differ in How They Use CCR5 for Entry

HIV-1 variants resistant to small molecule CCR5 inhibitors recognize the inhibitor-CCR5 complex, while also interacting with free CCR5. The most common genetic route to resistance involves sequence changes in the gp120 V3 region, a pathway followed when the primary isolate CC1/85 was cultured with the AD101 inhibitor in vitro, creating the CC101.19 resistant variant. However, the D1/86.16 escape mutant contains no V3 changes but has three substitutions in the gp41 fusion peptide. By using CCR5 point-mutants and gp120-targeting agents, we have investigated how infectious clonal viruses derived from the parental and both resistant isolates interact with CCR5. We conclude that the V3 sequence changes in CC101.19 cl.7 create a virus with an increased dependency on interactions with the CCR5 N-terminus. Elements of the CCR5 binding site associated with the V3 region and the CD4-induced (CD4i) epitope cluster in the gp120 bridging sheet are more exposed on the native Env complex of CC101.19 cl.7, which is sensitive to neutralization via these epitopes. However, D1/86.16 cl.23 does not have an increased dependency on the CCR5 N-terminus, and its CCR5 binding site has not become more exposed. How this virus interacts with the inhibitor-CCR5 complex remains to be understood.     

The tick saliva immunosuppressor, Salp15, contributes to Th17-induced pathology during Experimental Autoimmune Encephalomyelitis

Salp15 is a tick saliva protein that inhibits CD4⁺ T cell differentiation through its interaction with CD4. The protein inhibits early signaling events during T cell activation and IL-2 production. Because murine Experimental Autoimmune Encephalomyelitis development is mediated by central nervous system-infiltrating CD4⁺ T cells that are specific for myelin-associated proteins, we sought to determine whether the treatment of mice with Salp15 during EAE induction would prevent the generation of proinflammatory T cell responses and the development of the disease. Surprisingly, Salp15-treated mice developed more severe EAE than control animals. The treatment of EAE-induced mice with the tick saliva protein did not result in increased infiltration of T cells to the central nervous system, indicating that Salp15 had not affected the permeability of the blood-brain barrier. Salp15 treatment did not affect the development of antibody responses against the eliciting peptide or the presence of IFNγ in the sera. The treatment with Salp15 resulted, however, in the increased differentiation of Th17 cells in vivo, as evidenced by higher IL-17 production from PLP_139-151-specific CD4⁺ T cells isolated from the central nervous system and the periphery. In vitro, Salp15 was able to induce the differentiation of Th17 cells in the presence of IL-6 and the absence of TGFβ These results suggest that a conductive milieu for the differentiation of Th17 cells can be achieved by restriction of the production of IL-2 during T cell differentiation, a role that may be performed by TGFβ and other immunosuppressive agents.     

Ultrasound detection and characterization of polycystic kidney disease in a mouse model

We sought to use ultrasonography to quantify renal size and echogenicity in a mouse model of polycystic kidney disease. We imaged 36 wild-type (WT) and juvenile cystic kidney (jck) mice by using a standard ultrasound unit and 10-5 MHz linear transducer. Mice were imaged at 3 (6 WT, 7 jck), 6 (7 WT, 5 jck), and 9 (6 WT, 5 jck) wk of age. Kidney length, width, and height were recorded for volume calculation. Sagittal images of both kidneys were recorded for assessment of intensity. Quantitative values were obtained from areas of similar depth and gain settings. Kidney and liver intensities were determined for calculation of their ratio. Representative histologic kidney sections were stained with hematoxylin and eosin and digitized for calculation of cyst number, mean cyst area, and percentage cystic area. We found that renal volume was greater in jck than WT mice at 3 (P < 0.0001), 6 (P < 0.0001), and 9 (P < 0.0001) wk of age. In addition, kidney intensity and kidney:liver ratio were higher in jck than WT mice at 3 (P < 0.002 for both parameters), 6 (P < 0.04), and 9 wk (P < 0.008). Kidneys with smaller mean cyst size and less percentage cystic space had higher intensity values. We therefore conclude that ultrasound measures of renal volume and intensity can noninvasively identify jck-affected mice as early as 3 wk of age. Cortical intensity is greater in jck versus WT mice and appears affected by percentage cyst area and mean cyst size.     

Dosimetric evaluation study of IMRT and VMAT techniques for prostate cancer based on different multileaf collimator designs

The hypofractionated radiotherapy modality was established to reduce treatment durations and enhance therapeutic efficiency, as compared to conventional fractionation treatment. However, this modality is challenging because of rigid dosimetric constraints. This study aimed to assess the impact of multi-leaf collimator (MLC) widths (10 mm and 5 mm) on plan quality during the treatment of prostate cancer. Additionally, this study aimed to investigate the impact of the MLC mode of energy on the Agility flattening filter (FF), MLC Agility-free flattening filter (FFF), and MLCi2 for patients receiving hypofractionated radiotherapy. Two radiotherapy techniques; Intensity Modulated Radiotherapy (IMRT) and Volumetric Modulated Arc Radiotherapy (VMAT), were used in this research. In the present study, computed tomography simulations of ten patients (six plans per patient) with localized prostate adenocarcinoma were analyzed. Various dosimetric parameters were assessed, including monitor units, treatment delivery times, conformity, and homogeneity indices. To evaluate the plan quality, dose-volume histograms (DVHs) were estimated for each technique. The results demonstrated that the determined dosimetric parameters of planning target volume (PTV)p (such as D mean, conformity, and homogeneity index) showed greater improvement with MLC Agility FF and MLC Agility FFF than with MLCi2. Additionally, the treatment delivery time was reduced in the MLC Agility FF (by 31%) and MLC Agility FFF (by 10.8%) groups compared to the MLCi2 group. It is concluded that for both the VMAT and IMRT techniques, the smaller width (5 mm) MLCs revealed better planning target volume coverage, improved the dosimetric parameters for PTV, reduced the treatment time, and met the constraints for OARs. It is therefore recommended to use 5 mm MLCs for hypofractionated prostate cancer treatment due to better target coverage and better protection of OARs.