A facile, regioselective synthesis of novel 3-(N-phenylcarboxamide)pyrazolo[1,5-a]pyrimidine analogs in the presence of KHSO4 in aqueous media assisted by ultrasound and their antibacterial activities

An environmentally benign, simple, efficient, and convenient route is described for the synthesis of novel pyrazolo[1,5-a]pyrimidine derivatives under ultrasound irradiation. Condensation of aminopyrazole 5 with formylated active proton compounds (6, 8, E-G, 12, and 15) furnished pyrazolopyrimidine (7, 9, 10, 13, and 16) in high-to-excellent yields. In comparison with conventional methods, ultrasound irradiation offers several advantages, such as shorter reaction time, higher yields, milder conditions, and environmental friendliness. The reaction is clean with excellent yields and reduces the use of solvents. X-ray crystallographic study of compound 7c confirmed the regioselectivity of the reaction. The antibacterial profile of the newly synthesized compounds was evaluated by cup and saucer method.

Molecular characterization of tumor associated antigen in mice exposed to a hepatocarcinogen

The present investigation is aimed to identify and characterize tumor-associated antigen (TAA) in animals exposed to hepatocarcinogen. Swiss albino mice showed an enhanced expression of an approximately 58 kDa glycoprotein in liver cells upon exposure to a potential hepatocarcinogen N-nitrosodibutylamine (DBN). Carcinogenesis induction in mice was monitored by assays of y-glutamyl transpeptidase (GGT), acetylcholine esterase (AChE), glutathione-S-transferase (GST) activities and the level of glutathione (GSH) in liver. DBN treated animals showed cell distortion and extensive necrosis as observed by histological examination. The over-expressed TAA was purified by ion-exchange chromatography and further characterized by SDS-PAGE. The carbohydrate contents and glycan linkage to the polypeptide backbone was analyzed by using the DIG glycan differentiation and de-glycosylation kits. The glycoprotein has glycan chains that are N-linked via asparagines to the polypeptide backbone. It was also observed that the molecule is rich in sialic acid residues with a significantly high carbohydrate to protein ratio (> 2:1). The over-expressed high molecular weight glycoprotein TAA was found to be highly immunogenic and could eventually be used to induce immune response in order to counter tumor regression.

Radiomodulatory effect of liposome encapsulated AK-2123 on tumor in mice exposed to hepatocarcinogen

An attempt was made to evaluate the whole body gamma-radiation effect on tumor in the presence of free and liposome encapsulated AK-2123, a hypoxic cell radiosensitizer that has widely been used in combination with a number of cancer therapies such as thermotherapy, chemotherapy and radiotherapy. Entrapment efficiency of AK-2123 into liposome was determined by LASER Raman spectroscopy. Cancer induction in mice was carried out by repeated exposure of N-nitrosodiethylamine (DEN) in combination with partial hepatectomy. Parameters such as marker enzymes activities (GGT and AChE), rates of nucleic acid synthesis, viability modification factor and the histology of liver tissues monitored, supported the induction of cancer in liver. In addition, the effect of free as well as liposome encapsulated AK-2123 on haemopoietic parameters were also studied. It was observed that AK-2123 after incorporation into liposome afforded more efficient radiomodulatory effects than that of free AK-2123 as determined by the above-mentioned parameters. Neither free AK-2123 nor liposome encapsulated AK-2123 showed any detectable toxic effects on the mice. Thus, it is seen that treatment of cancer with a combination of radiation, a radiomodifier and a drug delivery system, opens a wide scope for exploitation for the improvement of existing cancer therapies.

Carcinogenesis response modulation induced by gelonin encapsulated in liposome

The effectiveness of gelonin to arrest protein synthesis, thereby limiting the growth of cancer cells was studied by encapsulating it into liposomes. The protein was extracted from the seeds of Indian plant Gelonium multiflorum by ammonium sulfate precipitation and purified using cation-exchange and gel-filtration chromatography. Biological activity of purified gelonin was determined using a rabbit reticulocyte lysate assay in the cell-free translational experiments. Gelonin was encapsulated in conventional liposomes prepared by the dry film method in order to retain biological activity of the entrapped protein. Carcinogenesis was induced in Swiss albino mice by intravenous administration of DBN (10 mg kg(-1) body weight) at weekly intervals. Marker enzyme assays (GGT, AChE, and GST), GSH levels, cell proliferation assay, hepatocyte DNA analysis, histological examination of micro sections of liver tissues were parameters used to monitor carcinogenesis induction, and regression in mice. From the in vitro experiments conducted, it was observed that gelonin upon its encapsulation into liposome, resulted in significant destruction of the transformed liver cells by its cytotoxic effects that arrest protein synthesis. Various parameters studied to monitor regression also suggested mass cell destruction to liver upon administration of liposomal gelonin in mice exposed to DBN.

Recruitment of calcineurin to the T cell receptor positively regulates T cell activation

Calcineurin is a phosphatase whose primary targets in T cells are NFAT transcription factors, and its inhibition with cyclosporin A (CsA) or FK506 is a cornerstone of immunosuppressive therapies. Here we show that calcineurin is recruited to the T cell receptor signaling complex where it reverses the inhibitory phosphorylation of Lck on Ser-59 (LckS59). Loss of calcineurin activity impaired phosphorylation of ZAP-70Y493 and some downstream pathways in a manner consistent with signaling in cells expressing LckS59A (non-phosphorylatable) or LckS59E (phosphomimetic). Importantly, CsA inhibited activation-induced LFA-1-dependent and NFAT-independent adhesion of T cells to ICAM-1, with little effect on cells expressing mutant Lck. These results provide a new understanding of how widely-used immunosuppressive drugs interfere with essential processes in the immune response.