Green sensitive spectrofluorimetric determination of pemetrexed as antineoplastic drug: Application in pharmaceutical dosage forms and spiked human plasma

A recent antineoplastic medication is pemetrexed, this medicine is now being developed and produced on a large scale, thus approaches for quality control are urgently needed. Spectrofluorimetric guidelines for the simple estimation of pemetrexed were validated. Pemetrexed's assay depends on observations of its native fluorescence at wavelengths 275/450 nm and pH 4. The proposed approach was also used to identify the examined drug in both its formulation and in human plasma that had been spiked.     

Prevalence of class I–III BRAF mutations among 114,662 cancer patients in a large genomic database

BRAF mutations are relatively common in many cancers, particularly melanoma, colorectal cancer, and thyroid cancer and to a lesser extent in lung cancer. These mutations can be targeted by BRAF and MEK inhibitors, which exhibit good clinical activity. There are conflicting reports of the various relative rates of BRAF Class I mutations (V600 locus), defined as those that exhibit extremely strong kinase activity by stimulating monomeric activation of BRAF, Class II, define as non-V600 mutations that activate BRAF to signal as a RAS-independent dimer, and Class III mutations, defined as “kinase-dead” with low kinase activity as compared to wild type BRAF. Prospective studies have largely focused on patients with tumors harboring Class I BRAF mutations (limited to the V600 locus) where response rates up to 70% with BRAF plus MEK inhibition have been demonstrated. We report on the relative prevalence of various types of BRAF mutations across human cancers in a cohort of 114,662 patients that received comprehensive genomic profiling using next-generation sequencing. Of these patients, 4517 (3.9%) a pathogenic or presumed pathogenic BRAF mutation (3.9%). Of these, 1271 were seen in melanoma, representing 39.7% of all melanomas sequenced, representing the highest rate in all tumors. Class I (V600) mutations were seen overall in 2841 patients (62.1% of BRAF mutations, 2.4% of total cancers). Class II mutations were seen in 746 tumors (16.5% of BRAF mutant, 0.7% of total), and Class III mutations were seen in 801 tumors (17.7% of BRAF, 0.7% of total). Knowledge of the relative prevalence of these types of mutations can aid in the development of agents that might better address non-V600 mutations in cancer.Impact statementThese data represent the largest aggregation of BRAF mutations within a single clinical database to our knowledge. The relative proportions of both BRAF V600 mutations and non-V600 mutations are informative in all cancers and by malignancy, and can serve as a definitive gold-standard for BRAF mutation cancer incidence by malignancy. The rate of BRAF mutation in human cancer in a real-world large database is lower than previously reported likely representing testing more broadly across tumor types. The relative percentages of Class II and Class III BRAF mutations are higher than previously reported, representing almost 35% of BRAF mutations in cancer. These findings provide support for the development of effective treatments for non-V600 BRAF mutations in cancer.     

Sensitivity of ruminal bacteria isolates of sheep,cattle and buffalo to some heavy metals

This study was conducted to investigate the toxicity of 12 heavy metals (i.e., HM), namely Hg, Cd, Co, Ni, Cr, Cu, Ag, Mo, Zn, Pb, Li and Na on bacterial isolates from the rumen of sheep, cattle and buffaloes. Rumen samples were collected immediately after slaughter during the dry season. Ruminal bacterial isolates, 59, were obtained from two sheep, five cows and nine buffaloes. Sensitivity of ruminal bacterial isolates to each HM was determined by the clearance zone (CZ) using the Kirby-Bauer disc diffusion susceptibility test. Bacterial populations isolated from the rumens of sheep and buffalo had a lower resistance (P<0.001) to HM toxicity than did cattle. Regardless of ruminant species, bacterial isolates revealed a higher tolerance (P<0.001) to Li and Na, whereas Hg and Cd were the most toxic HM for all isolates. We conclude that inhibition of these HM to the isolated microbial population of sheep, cattle and buffalo is ranked: Hg (most toxic) > Cd > Co ～ Ag ～ Cu ～ Cr ～ Ni > Mo ～ Zn ～ Pb > Li ～ Na. Further research is required to explain the mechanism of toxicity of these HM, and also to explore the variation among ruminant species.     

Supplement comprising of laccase and citric acid as an alternative for antibiotics: In vitro triggers of melanin production

An indiscriminate use of antibiotics in humans and animals has led to the widespread selection of antibiotic‐resistance, thus constricting the use of antibiotics. A possible solution to counter this problem could be to develop alternatives that can boost the host immunity, thus reducing the quantity and frequency of antibiotic use. In this work, for the first time, citric acid and laccase were used as extracellular inducers of melanin production in yeast cells and human cell lines. It is proposed that the formulation of laccase and citric acid together could further promote melatonin‐stimulated, melanocyte‐derived melanin production. Melanization as a probe of immunity described in this study, is an easy and a rapid test compared to other immunity tests and it allows performing statistical analyses. The results showed the synergistic effect of citric acid and laccase on melanin production by yeast cells, with significant statistical differences compared to all other tested conditions (p: 0.0005–0.005). Laccase and citric acid together boosted melanin production after 8 days of incubation. An increase in melanin production by two human colon cells lines (Cacao‐2/15 and HT‐29) was observed on supplementation with both laccase and citric acid in the cell growth medium. Produced melanin showed antimicrobial properties similar to antibiotics. Therefore, a formulation with citric acid and laccase may prove to be an excellent alternative to reduce the antibiotic use in human and animal subjects.     

Constitution of sargassan,a sulphated heteropolysaccharide from sargassum linifolium

The behaviour towards periodate of the brown-algal polysaccharide sargassan before and after partial hydrolysis, alkali treatment, and methanolysis has been studied. Evidence is thereby provided that the sargassan backbone is composed of (1→4)-linked β-D-glucuronic acid and β-D-mannose residues. Heteropolymeric, partially sulphated branches are attached to the backbone, and these branches comprise various proportions of(l→4)-linked, β-D-galactose, β-D-galactose 6-sulphate, and β-D-galactose 3,6-disulphate residues, (1→2)-linked α-L-fucose 4-sulphate residues, and (1→3)-linked β-D-xylose residues.     

Ecto-5′-nucleotidase regeneration after chemical modification of the plasma membrane

Treatment of the C6 glioblastoma cell with trinitrobenzenesulfonic acid (TNBS) resulted in the selective inactivation of ecto-5'-nucleotidase under conditions which maintained cell viability. Cells respond to ecto-enzyme inactivation by replacing 80% of lost activity within 24 hrs. A lag time of 4-6 hrs before ecto-5'-nucleotidase replacement began and its complete blockage by cycloheximide indicated that the source of replaced enzyme was de novo synthesis and not an intracellular pool. Release of 5'-nucleotidase activity into culture medium in the form of membraneous vesicles slowed during the active recovery period and then steadily increased with time as the plasma membrane enzyme level approached normal. TNBS did not exert a direct inhibitory action upon the exfoliative process as release of vesicular GM1 and protein were little affected. Decrease in exfoliated 5'-nucleotidase activity may be due to a selective conservation of the enzyme in the exfoliative process.     

Synthesis and biological activity of some new 3,6-dinitro-1:8-naphthaloyl- and 3,6-diamino-1:8-naphthaloylamino acids and dipeptide derivatives

Synthesis of a series of 3,6-dinitro-1:8-naphthaloylamino acids (II-IX) and some of their corresponding methyl esters (X-XVI) and 3,6-diamino-1:8-naphthaloylamino acid derivatives (XXIX-XXXVI) is described. Coupling of 3,6-dinitro-1:8-naphthaloylamino acids with amino acid methyl ester hydrochlorides in dioxane-DMF-Et3N medium using DCC method furnishes the desired 3,6-dinitro-1:8-naphthaloyldipeptide methyl esters (XVII-XXVIII). Most of the synthesized 3,6-dinitro-1:8-naphthaloylamino acids, esters and dipeptide derivatives (compounds III-VI, XI-XV, XVII, XIX-XXI, XXIII and XXV) and 3,6-diamino-1:8-naphthaloylamino acid derivatives (XXIX-XXXV) were found to be active against a number of microorganisms.     

Design of molecular switching and signaling based on proton transfer in 2-hydroxy Schiff bases: a computational study

The present work aims to exploit the possibility of using the tautomerism in 2-hydroxy Schiff bases for molecular switching. The enol imine (E)? enaminone (K) tautomerization in a series of 2-hydroxy Schiff bases have been investigated theoretically at the DFT/B3LYP/6-311G** level of theory. The intramolecular proton transfer processes have been explored, transition structures have been located and characterized. The kinetics and thermodynamics of the proton transfer process, and its time scale have been computed and discussed in the framework of the suitability as molecular switches. Substituent effects have been computed and its effect on the enthalpy changes (?H*) and activation energies (?G*) have been analyzed and discussed. Nonspecific solvent effects have also been taken into account by using the polarized continuum model (IPCM) of two different solvent. The tautomerization energies are decreased and hence the endothermic nature of the enol imine ? enaminone tautomerization. The potential energy barriers, on the other hand, are increased due to the relative destabilization of the transition states. The NBO charge populations show that there is a high positive charge on the hydrogen atom during the process in all cases, which confirms that the proton transfer proceeds through a three-center interaction. The proton transfer processes, in all cases studied are kinetically allowed. The low potential energy barrier suggests that interconversion between the two tautomeric forms is spontaneous and the two forms may coexist.