Randomized phase II trial of different schedules of administration of rebeccamycin analogue as second line therapy in non-small cell lung cancer

Summary Rebeccamcyin analogue (RA) is an antitumor antibiotic that results in DNA intercalation and topoisomerase I and II inhibition. Phase I trials of the daily × 5 schedule and once every 3 week schedule have been completed. Antitumor activity was observed during the phase I trials. The purpose of this study is to primarily determine the response rate of 2 different schedules of administration of RA in patients with advanced non-small cell lung cancer (NSCLC) who had progressed on one prior chemotherapy regimen. Secondary endpoints were median and 1-year survival rates. A two-stage Simon design was employed for both arms of the study. Patients were randomly assigned to either of two RA treatment schedules of 500 mg/m² as a 1 hr infusion repeated every 3 weeks (Arm A) or 140 mg/m²/day × 5 days repeated every 3 weeks (Arm B). Forty-two patients were randomized. No confirmed objective responses were seen. Stable disease was seen in 52% of patients on arm A and 37% on arm B. Median survival and 1 year survival rates were 5.6 months and 33.3% for arm A, 9.7 months and 42.1% for arm B respectively. Cox regression model demonstrated increased risk of death in patients younger than the age of 61 and for patients treated on arm A. RA failed to demonstrate a significant response rate in this disease setting, although the proportion of patients with stable disease and 1-year survival were encouraging and similar to other published studies of approved single agents for second-line therapy of NSCLC.     

Molecular modelling studies on the non-covalent intercalative interactions between DNA and the enantiomers of anti-benzo[a]pyrene 7,8-diol-9,10-epoxide

The non-covalent intercalative interactions between a deoxydinucleosidemodel for DNA and tbe enantiomers of anti-benzo[a]pyrene diol-epoxide,have been studied by molecular mechanics and computer graphicsmethods. Stereoselective differences between major and minorgroove sites, and between the enantiomers have been found interms of attractive close contacts.     

Bile acid metabolism in ascorbic acid-deficient guinea pigs.

Sterol balance techniques have been used to determine the effect of short-term ascorbic acid (AA) deprivation on bile acid excretion in the guinea pig. The effects of a brief (2-week) AA deficiency on bile acid pool sizes and the activity of the rate controlling enzyme in bile acid biosynthesis have been determined. It was found that, while food intake and body weight were not affected by the short-term AA deficiency, liver AA levels had fallen to 25% of control levels. At the same time, the rate of excretion of bile acids and the size of the bile acid pool were both reduced by about 50% in guinea pigs deficient in AA. These results were supported by a decrease in the activity of cholesterol 7 alpha-hydroxylase in the deficient animals. It is concluded that an AA deficiency will significantly impair bile acid metabolism independent of any side effects of clinical scurvy.     

Effect of a chronic tryptophan dietary deficiency on the rat's sleep-wake cycle

The deep-wake cycle of 12 tiyptophan dietary deficient rats and their non-deficient paired controls were observed for a 8:00 a.m. to 8:00 p.m. period. EEG, EMG and body activity were continuously monitored on polygraphic recordings throughout the 12 hr observation period. The results indicate no significant difference between the tryptophan deficient and sufficient animals in time spent awake, slow-wave or paradoxical sleep. There was a non-significant trend among the tryptophan deficient animals to be less active and spend more time in both slow-wave and paradoxical sleep, which is in contrast to an expected insomnia effect. The results do not support the suggested relationship between reduced serotonin levels and the occurrence of insomnia, questioning the serotonergic theory of sleep.     

Evaluation of efficacy and safety of nimesulide with betacyclodextrin vs nimesulide tablets in osteoarthritis

Efficacy and safety of nimesulide as well as favourable tolerability have been tested in osteoarthritis in short term study and post-marketing survey. Here is a report which shows the superiority of nimesulide complexed with betacyclodextrin vs ninesulide tablet in osteoarthritis in a long term study.     

Uptake and protection against oxidative stress by estrogen esters in THP-1 human macrophage cell lines

Estrogen replacement therapy offers protection from coronary artery disease in postmenopausal women. However, there is serious concern that long-term unopposed estrogen use increases the risk of breast and endometrial cancer through estrogen-receptor-driven mechanisms. In this communication, we have explored an alternate route of estrogen delivery to macrophages using hydrophobic derivatives that associate with lipoproteins. Unlike free estradiol (E(2)), long-chain fatty acid esters of E(2) associate extensively with low-density lipoprotein (LDL). In THP-1 cells, E(2) esters accumulated to a significantly higher level when compared to E(2) in the presence of LDL. In the presence of oxidized LDL even greater amounts of E(2) esters accumulated in cells. In THP-1 cells, E(2) esters were capable of preventing the azo-bis-induced increase in oxidative stress (hydrogen peroxide formation). These studies suggest that (a) hydrophobic esters of estrogens that associate with LDL can be delivered to macrophages and (b) these esters can effectively function as antioxidants protecting against oxidative stress.     

Prostaglandin E2 biosynthesis and effect in pigeon aorta. Possible role in atherogenesis.

This study for the first time examines the biosynthesis and effect of prostaglandin E2 (PGE2) in aorta during genetic atherosclerosis. Biosynthesis of PGE2 from [1-14C]arachidonic acid was investigated in the aorta of spontaneously atherosclerosis-susceptible White Carneau pigeons and was compared with that of the atherosclerosis-resistant Show Racer breed. Most of the PGE2 synthetase activity was located in the microsomes. The synthesis was linear up to an hour and was optimal at pH 7.4. The formation of PGE2 in the aorta in the White Carneau pigeons was significantly higher (P less than 0.01) than that in age-matched Show Racer pigeons. In vitro PGE2 strongly inhibited the cholesteryl ester hydrolase activity (51.6% inhibition at 4 X 10(-7) M concentration) in the supernatant fraction of the aorta. On the basis of (1) the increased formation of PGE2 in the aorta of atherosclerosis-susceptible pigeons and (2) its effect on specific enzymes that control cholesteryl ester concentration in aorta, it is hypothesized that PGE2 synthesized at a higher rate in damaged aorta has a significant role in cholesteryl ester accumulation during atherogenesis.     

Quantitative analysis of hydrogen and chalcogen bonds in two pyrimidine-5-carbonitrile derivatives,potential DHFR inhibitors: an integrated crystallographic and theoretical study

Two potential bioactive pyrimidine-5-carbonitrile derivatives have been synthesized and characterized by spectroscopic techniques (¹H and ¹³C-NMR) and the three dimensional structures were elucidated by single crystal X-ray diffraction at low temperature (160 K). In both structures, the molecular conformation is locked by an intramolecular C–H⋯C interaction involving the cyano and CH of the thiophene and phenyl rings. The intermolecular interactions were analyzed in a qualitative manner based on the Hirshfeld surface and 2D-fingerprint plots. The results suggest that the phenyl and thiophene moieties have an effect on the crystal packing. For instance, the chalcogen bonds are only preferred in the thiophene derivative. However, both structures uses a common N–H⋯O hydrogen bond motif. Moreover, the structures of 1 and 2 display 1D isostructurality and molecular chains stabilize by intermolecular N–H⋯O and N–H⋯N hydrogen bonds. The nature and extent of different non-covalent interactions were further characterized by the topological parameters derived from the quantum theory of atoms-in-molecules approach. This analysis indicates that apart from N–H⋯O hydrogen bonds, other non-covalent interactions are closed-shell in nature. A strong and linear N–H⋯O hydrogen bond shows intermediate bonding character between shared and closed-shell interactions. The molecular docking analysis suggests that both compounds display potential inhibitory effect against the dihydrofolate reductase (DHFR) enzyme from humans and Staphylococcus aureus.

Qualitative and quantitative analyses of hydrogen and chalcogen bonds in two pyrimidine-5-carbonitrile derivatives are described.