Vibrational Analysis of Metal Complexes of 1,3-Dithiomalonamide & 2,4-Dithiobiuret

591-59

Normal Vibrations of Guanyl Thiourea-d0 & Thiourea-d6

306-30

Dexamethasone protected human glioblastoma U87MG cells from temozolomide induced apoptosis by maintaining Bax:Bcl-2 ratio and preventing proteolytic activities

BACKGROUND: Glioblastoma is the deadliest and most prevalent brain tumor. Dexamethasone (DXM) is a commonly used steroid for treating glioblastoma patients for alleviation of vasogenic edema and pain prior to treatment with chemotherapeutic drugs. Temozolomide (TMZ), an alkylating agent, has recently been introduced in clinical trials for treating glioblastoma. Here, we evaluated the modulatory effect of DXM on TMZ induced apoptosis in human glioblastoma U87MG cells. RESULTS: Freshly grown cells were treated with different doses of DXM or TMZ for 6 h followed by incubation in a drug-free medium for 48 h. Wright staining and ApopTag assay showed no apoptosis in cells treated with 40 μM DXM but considerable amounts of apoptosis in cells treated with 100 μM TMZ. Apoptosis in TMZ treated cells was associated with an increase in intracellular free [Ca(2+)], as determined by fura-2 assay. Western blot analyses showed alternations in the levels of Bax (pro-apoptotic) and Bcl-2 (anti-apoptotic) proteins resulting in increased Bax:Bcl-2 ratio in TMZ treated cells. Western blot analyses also detected overexpression of calpain and caspase-3, which cleaved 270 kD α-spectrin at specific sites for generation of 145 and 120 kD spectrin break down products (SBDPs), respectively. However, 1-h pretreatment of cells with 40 μM DXM dramatically decreased TMZ induced apoptosis, decreasing Bax:Bcl-2 ratio and SBDPs. CONCLUSION: Our results revealed an antagonistic effect of DXM on TMZ induced apoptosis in human glioblastoma U87MG cells, implying that treatment of glioblastoma patients with DXM prior to chemotherapy with TMZ might result in an undesirable clinical outcome

Synthesis, characterizations and biological screening of tetrahydro-quinazoline analogues

Abstract Quinazoline and their fused-ring systems are well known for their potential biological activity. In the present study a new Tetrahydro-quinazoline analogues (MB I-V) were synthesized. The newly synthesized compounds were characterized by IR, NMR and C, H, N, S analyses. All newly synthesized compounds were screened for their antibacterial (Pseudomonas aurigenosa Bacillus subtilis and Escherichia coli) studies. The results revealed that all synthesized compounds have a significant biological activity against the tested microorganisms

Molecular orbital studies on some 4-substituted pyridine N-oxides and 4-nitroquinoline N-oxide

The electronic structures of a series of 4-substituted pyridine N-oxides and 4-nitroquinoline N-oxide are investigated using the simple Pariser-Parr-Pople (PPP), a modified PPP, IEH and MINDO/2 methods. The electronic absorption band maxima and dipole moments are calculated and compared with experimental values. The photoelectron spectra of these compounds are assigned. The nature of the N-oxide group is characterized using the orbital population distributions. The antifungal activity exhibited by some of these compounds is discussed in terms of the nucleophilic frontier electron densities, superdelocalizabilities and electron acceptor properties. The effect of the electron releasing as well as the electron withdrawing substituents on the physico-chemical properties is explained

A Reinvestigation of the Normal Vibrations of Thioacetamide

The normal coordinate treatments of thioacetamide and its seven isotopic molecules have been carried out using Urey-Bradley force constants refined by a least-squares procedure. The laser Raman spectrum of thioacetamide has also been recorded

Structure-conductivity correlation in organic polymers: An MO approach

321-323The poor electrical conductivity of polyphenylene sulphide (PPS) has been rationalised on the basis of Pariser-Parr-Pople MO method. This approach has been extended to explain the conductivity of polyphenylene oxide (PPO). The change in conductivity of polystilbene by replacing phenylene unit with thiadiazole and thiophene units has been discussed in the light of MO calculation. However, the reported conductivities could not be rationalised on the basis of this simple MO calculation

Infrared and Raman spectra of 2,4-dithiobiuret and its normal vibrations

The infrared spectra of 2,4-dithiobiuret(DTB), N-deuterated dithiobiuret(DTB-d5) and the laser Raman spectrum of DTB are reported. Normal coordinate treatments of DTB and DTB-d5 have been carried out to aid the assignment of the vibrational frequencies. A trans—cis conformation is favoured for DTB molecule in the solid state

Spectroscopic and Coordination Behavior of α-Cyanothioacetamide

α-Cyanothioacetamide (CTAM) complexes of cuprous chloride CuCl–2CTAM and cuprous bromide CuBr–2CTAM have been prepared. The infrared spectra of CTAM and its complexes, and the laser Raman spectrum of CTAM have been recorded. Assignment of the frequencies of the ligand has been made on the basis of a normal coordinate analysis using the Urey-Bradley force field. The copper (I) complexes are inferred to have thiocarbonyl sulfur and amide nitrogen bonded CTAM as evidenced from infrared and electronic spectra