Electrochemical evaluation of nivolumab used in cancer treatment with differential pulse voltammetry: A novel approach with single-use pencil graphite electrode.

OBJECTIVES: Nivolumab is used in a treatment called immunotherapy, which helps the immune system cells to attack cancer cells. The electrochemical properties and quantification of this drug were performed using single-use pencil tips. EVIDENCE ACQUISITION: Here, a selective voltammetric method for the determination and electrochemical characterization of Nivolumab used in cancer therapy was developed for the first time using a disposable pencil electrode by cyclic voltammetry and differential pulse voltammetry techniques. Nivolumab exhibited an anodic signal at +0.879 V (vs. Ag/AgCl) in PBS (pH 3.0, 0.02 M NaCl) medium. RESULTS: This procedure showed a linear response in phosphate buffer solutions (pH 3.0, 0.02 M NaCl) media within the concentration range of 0.01 mg mL-1 to 0.07 mg mL-1 and limit of detection and the limit of quantification values were determined to be 2.49 µg mL-1 and 8.30 µg mL-1, respectively. CONCLUSIONS: The developed method offers an important analytical approach for the detection and characterization of NIVO. Precisely measuring and monitoring the levels of such drugs in real sample analyses or biological samples is critical for evaluating response to treatment, optimizing treatment strategies. Therefore, the method was applied to real sample analyses. Voltammetric results developed using PG electrode were compared with UV-Vis results. It has been determined that the results obtained are compatible with each other.

Voltammetric studies and spectroscopic investigations of the interaction of an anticancer drug bevacizumab-DNA and analytical applications of disposable pencil graphite sensor.

A sensitive, simple, fast electrochemical biosensor for the DNA interaction of bevacizumab (BEVA), which is used as a targeted drug in cancer treatment, was developed using the differential pulse voltammetry (DPV) technique with pencil graphite electrode (PGE). In the work, PGE was electrochemically activated in a supporting electrolyte medium of +1.4 V/60 s (PBS pH 3.0). Surface characterization of PGE was carried out by SEM, EDX, EIS, and CV techniques. Determination and electrochemical properties of BEVA were examined with CV and DPV techniques. BEVA gave a distinct analytical signal on the PGE surface at a potential of +0.90 V (vs. Ag/AgCl). In the procedure proposed in this study, BEVA gave a linear response on PGE in PBS (pH 3.0 containing 0.02 M NaCl) (0.1 mg mL-1 - 0.7 mg mL-1) with LOD and LOQ values of 0.026 mg mL-1 and 0.086 µg mL-1, respectively. BEVA was reacted with 20 µg mL-1 DNA in PBS for 150 s and analytical peak signals for adenine and guanine bases were evaluated. The interaction between BEVA-DNA was supported by UV-Vis. Absorption spectrometry and the binding constant was determined as 7.3 × 104.

Quantitative determination and removal of pesticide residues in fresh vegetables and fruit products by LC-MS/MS and GC-MS/MS.

Pesticides are the potent agrochemicals used to successfully manage, repel, or stop pests and weeds in agricultural production. This study analyzed 222 pesticide active substances in 90 samples of seven different vegetables and fruits acquired from producers through liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS) and gas chromatography-mass spectrometry/mass spectrometry (GC-MS/MS) technology. The validation parameters of each pesticide's active substances were determined. The LOD, LOQ values, and recovery studies of the 222 active substances were 3.00, 10.00 ng/g, and between 76.07 and 108.08%, respectively. The correlation coefficients and measurement uncertainty were determined to be between 0.990-0.999 and 8.91-31.46%, respectively. There were active substances of chlorpyrifos, acetamiprid, azoxystrobin, difenoconazole, malathion, dieldrin, boscalid, triticonazole, tebuconazole, triadimenol, trifloxystrobin, pirimicarb, and dodine among the vegetable and fruit samples used in the study. There were no active substances in 55 (61%) samples. Among the 35 samples (39%), 31 samples (34%) contained only one active substance, whereas four (5%) contained two active substances. However, the amount of active substances in six (7%) samples was above the maximum residue levels (MRL) limits. Various processes used in the study revealed that peeling was the most effective pesticide residue removal strategy. The washing procedure also proved that it reduced some pesticide residues but failed to eliminate all pesticides. The peeling process successfully reduced a significant amount of the active substances from the products, however, residues remained. Washing the fruits with hot water was also effective in removing residues. As a result, analyses of the peeled sections yielded higher pesticide residue concentrations than those of the entire product.

A new method to reduce false positives due to antimony in detection of gunshot residues.

False positives due to the presence of antimony in vehicle seat fabrics are a problem in gunshot residue (GSR) analysis, in particular, when graphite furnace atomic absorption spectrometry (GFAAS) is employed. In this study, we sought to determine the reason for the prevalence of false positive results and to propose a new approach for the analysis of GSR on vehicle seats. GFAAS was used to examine adhesive tape swabs collected from 100 seats of 50 different automobiles. Characterization of seat fabrics was carried out by using Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy with energy dispersive X-ray (SEM/EDX) spectroscopy. The results of FTIR analysis indicated that all seat covers containing antimony were composed of polyester. Experimental results obtained by SEM/EDX analysis revealed that the fabrics in these seat covers contained evenly distributed antimony within the structure of polyester fibers. This study shows that the type of seat fabric should be determined by FTIR spectroscopy before elemental GSR analysis. In this way, most of the false positives caused by polyester fibers in GSR analysis can be prevented.

Phosphorus speciation in the surface sediment and river water from the Orontes (Asi) River, Turkey.

The paper presents the results of the distribution of phosphorus bioavailability (total, organic, and inorganic phosphorus) in surface sediment and river water from the Orontes (Asi) River (Samandag, Antakya, Turkey) in March 2008. Speciation of inorganic phosphorus was carried out using a method on sequential extractions, with each releasing four forms of inorganic phosphorus-loosely sorbed phosphorus, phosphorus bound to aluminum (P-AL), phosphorus bound to iron (P-Fe), and phosphorus bound to calcium (P-Ca). Total phosphorus concentrations are, on average, 3.724 mg/L and 312.30 mg/kg dry weight in the river water and surface sediment, respectively. The interstitial water of the surface sediment contains less than 1% of the surface sediment's total phosphorus pool. The most abundant form of inorganic phosphorus is P-Ca. Relative abundances of the remaining phosphorus forms both in surface sediment and river water follow the order P-Al > loosely bound-P > P-Fe.

A sequential extraction to determine the distribution of phosphorus in the seawater and marine surface sediment.

The distribution of phosphorus species among environmental compartments (e.g., between water and sediment), significantly affects the bioavailability of these species to organisms. The eastern Mediterranean Sea is one of the most extreme oligotrophic oceanic regions on earth in terms of nutrient concentrations and primary productivity. The paper presents the results of inorganic and organic forms in surface sediment and seawater from NE Mediterranean Sea (Burclar Bay, Erdemli, South Anatolia of Turkey) in May 2007. Speciation of phosphorus in seawater and surface sediment using inductively coupled plasma-atomic emission spectrometer (ICP-AES) has been reported here. The method is based on sequential extractions of the seawater and sediment each releasing four forms of inorganic phosphorus: loosely sorbed phosphorus, phosphorus bound to aluminium (P-Al), phosphorus bound to iron (P-Fe) and phosphorus bound to calcium (P-Ca). The most abundant form of inorganic phosphorus in the seawater and surface sediment is calcium-bound phosphorus. Relative abundances of the remaining phosphorus forms in sediment follow the order: P-Al>P-Fe>loosely bound-P and in seawater follow the order P-Fe>P-Al>loosely bound-P.

Synthesis and monoamine oxidase inhibitory activities of 1-thiocarbamoyl-3,5-diphenyl-4,5-dihydro-1H-pyrazole derivatives.

Ten new 1-thiocarbamoyl-3-(phenyl and/or 4-substituted phenyl)-5-(3,4-dimethoxyphenyl and/or 2-chloro-3,4-dimethoxyphenyl)-4,5-dihydro-1H-pyrazole derivatives were synthesized by reacting 1,3-diphenylpropen-1-ones and thiosemicarbazide. The chemical structures of the compounds were verified by means of their IR, 1H-NMR, ESI-MS spectroscopic data and elementary analyses. All the compounds were investigated for their ability to selectively inhibit monoamine oxidase (MAO) by in-vitro tests. Monoamine oxidase was isolated and purified from the mitochondrial extracts of rat-liver homogenates and human platelets. Monoamine oxidase inhibitory activities of the compounds were compared with pargyline and clorgyline. Most of the compounds inhibited the total activity of rat liver homogenates. The monoamine oxidase-A inhibitory effects of 1-thiocarbamoyl-3-(4-methoxyphenyl)-5-(3,4-dimethoxyphenyl)-4,5-dihydro-1H-pyrazole and 1-thiocarbamoyl-3-(4-methoxyphenyl)-5-(2-chloro-3,4-dimethoxyphenyl)-4,5-dihydro-1H-pyrazole were detected as potent as clorgyline. Selective and irreversible inhibition of rat liver monoamine oxidase-A by synthesized compounds have promising features for designing the new selective monoamine oxidase A inhibitors as potent and reliable anti-depressants in the future.

Effects of dietary boron on cervical cytopathology and on micronucleus frequency in exfoliated buccal cells.

Recent evidence indicates that boron and borates may have anticarcinogenic properties. In this study, we have investigated the incidence of adverse cytological findings in cervical smears and the micronucleus (MN) frequency in women living in boron-rich and boron-poor regions. Cervical smears were prepared from 1059 women with low socioeconomic status; 472 of the women lived in relatively boron-rich rural areas, while 587 lived in relatively boron-poor regions. The average and standard deviation values for the age of the women screened with the cervical Pap smear test were 41.55 +/- 8.38. The mean dietary intake of boron was 8.41 mg/day for women from the boron-rich regions, and 1.26 mg/day for women living in the boron-poor regions (P < 0.0001). Women from the boron-rich regions had no cytopathological indications of cervical cancer, while there were cytopathological findings for 15 women from the boron-poor areas (chi(2) = 10.473, P < 0.05). Sixty women, 30 from each region, were chosen for evaluating MN frequencies in exfoliated buccal cells. MN frequencies for women from the boron-rich and boron-poor regions were not significantly different (t = -0.294, P > 0.05). Also, there were no significant correlations between age and MN frequency for women from both the boron-rich (r = 0.133, P = 0.48, P > 0.05) and boron-poor (r = -0.033, P = 0.861, P > 0.05) regions. The results suggest that ingestion of boron in the drinking water decreases the incidence of cervical cancer-related histopathological findings. There was no correlation between the pathological findings from the cervical smears and buccal cell MN frequency suggesting that the two study populations were exposed equally to gentotoxic agents. Nonetheless, cervical cancer-related histopathological findings should be validated by other researchers.