Unprecedented homotopy perturbation method for solving nonlinear equations in the enzymatic reaction of glucose in a spherical matrix.

The theory of glucose-responsive composite membranes for the planar diffusion and reaction process is extended to a microsphere membrane. The theoretical model of glucose oxidation and hydrogen peroxide production in the chitosan-aliginate microsphere has been discussed in this manuscript for the first time. We have successfully reported an analytical derived methodology utilizing homotopy perturbation to perform the numerical simulation. The influence and sensitive analysis of various parameters on the concentrations of gluconic acid and hydrogen peroxide are also discussed. The theoretical results enable to predict and optimize the performance of enzyme kinetics

Zeptomole Electrochemical Detection of Metallothioneins

Thiol-rich peptides and proteins possess a large number of biological activities and may serve as markers for numerous health problems including cancer. Metallothionein (MT), a small molecular mass protein rich in cysteine, may be considered as one of the promising tumour markers. The aim of this paper was to employ chronopotentiometric stripping analysis (CPSA) for highly sensitive detection of MT.In this study, we used adsorptive transfer stripping technique coupled with CPSA for detection of cysteine, glutathione oxidized and reduced, phytochelatin, bovine serum albumin, and metallothionein. Under the optimal conditions, we were able to estimate detection limits down to tens of fg per ml. Further, this method was applied to detect metallothioneins in blood serum obtained from patients with breast cancer and in neuroblastoma cells resistant and sensitive to cisplatin in order to show the possible role of metallothioneins in carcinogenesis. It was found that MT level in blood serum was almost twice higher as compared to the level determined in healthy individuals.This paper brings unique results on the application of ultra-sensitive electroanalytical method for metallothionein detection. The detection limit and other analytical parameters are the best among the parameters of other techniques. In spite of the fact that the paper is mainly focused on metallothionein, it is worth mentioning that successful detection of other biologically important molecules is possible by this method. Coupling of this method with simple isolation methods such as antibody-modified paramagnetic particles may be implemented to lab-on-chip instrument

Deoxynivalenol and its toxicity

Deoxynivalenol (DON) is one of several mycotoxins produced by certain Fusarium species that frequently infect corn, wheat, oats, barley, rice, and other grains in the field or during storage. The exposure risk to human is directly through foods of plant origin (cereal grains) or indirectly through foods of animal origin (kidney, liver, milk, eggs). It has been detected in buckwheat, popcorn, sorgum, triticale, and other food products including flour, bread, breakfast cereals, noodles, infant foods, pancakes, malt and beer. DON affects animal and human health causing acute temporary nausea, vomiting, diarrhea, abdominal pain, headache, dizziness, and fever. This review briefly summarizes toxicities of this mycotoxin as well as effects on reproduction and their antagonistic and synergic actions

DNA and histone deacetylases as targets for neuroblastoma treatment

Neuroblastoma, a tumor of the peripheral sympathetic nervous system, is the most frequent solid extra cranial tumor in children and is a major cause of death from neoplasia in infancy. Still little improvement in therapeutic options has been made, requiring a need for the development of new therapies. In our laboratory, we address still unsettled questions, which of mechanisms of action of DNA-damaging drugs both currently use for treatment of human neuroblastomas (doxorubicin, cis-platin, cyclophosphamide and etoposide) and another anticancer agent decreasing growth of neuroblastomas in vitro, ellipticine, are predominant mechanism(s) responsible for their antitumor action in neuroblastoma cell lines in vitro. Because hypoxia frequently occurs in tumors and strongly correlates with advanced disease and poor outcome caused by chemoresistance, the effects of hypoxia on efficiencies and mechanisms of actions of these drugs in neuroblastomas are also investigated. Since the epigenetic structure of DNA and its lesions play a role in the origin of human neuroblastomas, pharmaceutical manipulation of the epigenome may offer other treatment options also for neuroblastomas. Therefore, the effects of histone deacetylase inhibitors on growth of neuroblastoma and combination of these compounds with doxorubicin, cis-platin, etoposide and ellipticine as well as mechanisms of such effects in human neuroblastona cell lines in vitro are also investigated. Such a study will increase our knowledge to explain the proper function of these drugs on the molecular level, which should be utilized for the development of new therapies for neuroblastomas

Copper Concentrations in Breast Cancer: A Systematic Review and Meta-Analysis

Breast cancer is the most common neoplasm, comprising 16 of all women's cancers worldwide. Research of Copper (Cu) concentrations in various body specimens have suggested an association between Cu levels and breast cancer risks. This systematic review and meta-analysis summarize the results of published studies and examine this association. We searched the databases PubMed, Scopus, Web of Science, and Google Scholar and the reference lists of relevant publications. The Standardized Mean Differences (SMDs) between Cu levels in cancer cases and controls and corresponding Confidence Intervals (CIs), as well as I-2 statistics, were calculated to examine heterogeneity. Following the specimens used in the original studies, the Cu concentrations were examined in three subgroups: serum or plasma, breast tissue, and scalp hair. We identified 1711 relevant studies published from 1984 to 2017. There was no statistically significant difference between breast cancer cases and controls for Cu levels assayed in any studied specimen; the SMD (95 CI) was -0.01 (-1.06 - 1.03; P = 0.98) for blood or serum, 0.51 (-0.70 - 1.73; P = 0.41) for breast tissue, and -0.88 (-3.42 - 1.65; P = 0.50) for hair samples. However, the heterogeneity between studies was very high (P < 0.001) in all subgroups. We did not find evidence for publication bias (P = 0.91). The results of this meta-analysis do not support an association between Cu levels and breast cancer. However, due to high heterogeneity in the results of original studies, this conclusion needs to be confirmed by well-designed prospective studies

The evaluation of virus symptoms and fruit quality of GMO, PPV-Resistant P. domestica 'HoneySweet' grown in the open field under a high and permanent infection pressure of PPV, ACLSV, and PDV

Transgenic, 'HoneySweet' plums inoculated with Plum pox virus, recombinant strain (PPV-Rec) alone, PPV-Rec + Apple chlorotic leafspot virus (ACLSV), PPV-Rec + Prune dwarf virus (PDV), and PPV-Rec + ACLSV + PDV were grown in an open field under high and permanent infection pressure both from graft inoculation and natural aphid vectors for 8 years. 'HoneySweet' control trees were non-graft-inoculated trees. Plants were monitored by symptomology, DAS-ELISA, semiquantitative (SQ)-ELISA, and real-time (RT)-PCR. Inoculum shoots showed severe PPV symptoms from the first year after inoculation throughout the study. Mild PPV symptoms appeared in some of the basal leaves of graft-inoculated 'HoneySweet' trees in the second year following inoculation. During the following six years, even these mild and isolated symptoms on 'HoneySweet' trees diminished. The presence of PPV in these basal areas of 'HoneySweet' trees was confirmed by ELISA, ISEM, and RT-PCR. Relative concentration of PPV determined by SQ-ELISA and by RT-PCR was lower than in leaves of inoculum shoots. No difference in PPV symptoms was observed between PPV-Rec, and combinations PPV-Rec with other viruses. While no symptoms of ACLSV appeared during the study, ACLSV was detected by ELISA and RT-PCR. No symptoms of PDV appeared and PDV was not detected. 'HoneySweet' trees exposed to natural aphid-vectored PPV were not infected. Fruits of 'HoneySweet' were qualitatively and quantitatively compared with fruits of 'Stanley' and 'Domaci svestka' in 2010 from noninfected trees of 'HoneySweet' and fruits from 'HoneySweet' trees graft-inoculated with PPV-Rec + ACLSV + PDV were both of high quality and comparable to, or for certain characteristics, of higher quality than fruit of the commercial cultivars which were evaluated

The evaluation of virus symptoms and fruit quality of GMO, PPV-Resistant P. domestica 'HoneySweet' grown in the open field under a high and permanent infection pressure of PPV, ACLSV, and PDV

Transgenic, 'HoneySweet' plums inoculated with Plum pox virus, recombinant strain (PPV-Rec) alone, PPV-Rec + Apple chlorotic leafspot virus (ACLSV), PPV-Rec + Prune dwarf virus (PDV), and PPV-Rec + ACLSV + PDV were grown in an open field under high and permanent infection pressure both from graft inoculation and natural aphid vectors for 8 years. 'HoneySweet' control trees were non-graft-inoculated trees. Plants were monitored by symptomology, DAS-ELISA, semiquantitative (SQ)-ELISA, and real-time (RT)-PCR. Inoculum shoots showed severe PPV symptoms from the first year after inoculation throughout the study. Mild PPV symptoms appeared in some of the basal leaves of graft-inoculated 'HoneySweet' trees in the second year following inoculation. During the following six years, even these mild and isolated symptoms on 'HoneySweet' trees diminished. The presence of PPV in these basal areas of 'HoneySweet' trees was confirmed by ELISA, ISEM, and RT-PCR. Relative concentration of PPV determined by SQ-ELISA and by RT-PCR was lower than in leaves of inoculum shoots. No difference in PPV symptoms was observed between PPV-Rec, and combinations PPV-Rec with other viruses. While no symptoms of ACLSV appeared during the study, ACLSV was detected by ELISA and RT-PCR. No symptoms of PDV appeared and PDV was not detected. 'HoneySweet' trees exposed to natural aphid-vectored PPV were not infected. Fruits of 'HoneySweet' were qualitatively and quantitatively compared with fruits of 'Stanley' and 'Domaci svestka' in 2010 from noninfected trees of 'HoneySweet' and fruits from 'HoneySweet' trees graft-inoculated with PPV-Rec + ACLSV + PDV were both of high quality and comparable to, or for certain characteristics, of higher quality than fruit of the commercial cultivars which were evaluated

Sensitive Electrochemical Detection of Native and Aggregated x-Synuclein Protein Involved in Parkinson's Disease

The aggregation of α-synuclein, a 14 kDa protein, is involved in several human neurodegenerative disorders, including Parkinson's disease. We studied native and in vitro aggregated α-synuclein by circular dichroism (CD), atomic force microscopy (AFM) and electrochemical methods. We used constant current chronopotentiometric stripping analysis (CPSA) to measure hydrogen evolution catalyzed by α-synuclein (peak H) at hanging mercury drop electrodes (HMDE) and square-wave stripping voltammetry (SWSV) to monitor tyrosine oxidation at carbon paste electrodes (CPE). To decrease the volume of the analyte, most of the electrochemical measurements were performed by adsorptive transfer (medium exchange) from 3-6 L drops of α-synuclein samples. With both CPE and HMDE we observed changes in electrochemical responses of α-synuclein corresponding to protein fibrillization detectable by CD, fluorescence and AFM. Aggregation-induced changes in peak H at HMDE were relatively large in strongly aggregated samples, suggesting that this electrochemical signal may find use in the analysis of early stages of α-synuclein aggregation. This assumption was documented by marked changes in the peak H potential and height in samples withdrawn at the end of the lag and the beginning of the elongation phase. Native α-synuclein can be detected down to subnanomolar concentrations by CPSA

Sensitive electrochemical detection of native and aggregated α-synuclein protein involved in Parkinson's Disease

The aggregation of α-synuclein, a 14 kDa protein, is involved in several human neurodegenerative disorders, including Parkinson´s disease. We studied native and in vitro aggregated α-synuclein by circular dichroism (CD), atomic force microscopy (AFM) and electrochemical methods. We used constant current chronopotentiometric stripping analysis (CPSA) to measure hydrogen evolution catalyzed by α-synuclein (peak H) at hanging mercury drop electrodes (HMDE) and square wave stripping voltammetry (SWSV) to monitor tyrosine oxidation at carbon paste electrodes (CPE). To decrease the volume of the analyte, most of the electrochemical measurements were performed by adsorptive transfer (medium exchange) from 3-6 μL drops of α-synuclein samples. With both CPE and HMDE we observed changes in electrochemical responses of a-synuclein corresponding to protein fibrillization detectable by CD, fluorescence and AFM. Aggregation-induced changes in peak H at HMDE were relatively large in strongly aggregated samples, suggesting that this electrochemical signal may find use in the analysis of early stages of α-synuclein aggregation. This assumption was documented by marked changes in the peak H potential and height in samples withdrawn at the end of the lag and the beginning of the elongation phase. Native α-synuclein can be detected down to subnanomolar concentrations by CPSA