Prenatal exposure to a mixture of organophosphate flame retardants and infant neurodevelopment: A prospective cohort study in Shandong, China.

BACKGROUND: Previous studies have suggested that prenatal exposure to organophosphate flame retardants (OPFRs) may have adverse effect on early neurodevelopment, but limited data are available in China, and the overall effects of OPFRs mixture are still unclear. OBJECTIVE: This study aimed to investigate the association between prenatal exposure to OPFR metabolites mixture and the neurodevelopment of 1-year-old infants. METHODS: A total of 270 mother-infant pairs were recruited from the Laizhou Wan (Bay) Birth Cohort in China. Ten OPFR metabolites were measured in maternal urine. Neurodevelopment of 1-year-old infants was assessed using the Gesell Developmental Schedules (GDS) and presented by the developmental quotient (DQ) score. Multivariate linear regression and weighted quantile sum (WQS) regression models were conducted to estimate the association of prenatal exposure to seven individual OPFR metabolites and their mixture with infant neurodevelopment. RESULTS: The positive rates of seven OPFR metabolites in the urine of pregnant women were greater than 70% with the median concentration ranged within 0.13-3.53 µg/g creatinine. The multivariate linear regression model showed significant negative associations between bis (1-chloro-2-propyl) phosphate (BCIPP), din-butyl phosphate (DnBP), and total OPFR metabolites exposure and neurodevelopment in all infants. Results from the WQS model consistently revealed that the OPFR metabolites mixture was inversely associated with infant neurodevelopment. Each quartile increased in the seven OPFR metabolites mixture was associated with a 1.59 decrease (95% CI: 2.96, -0.21) in gross motor DQ scores, a 1.41 decrease (95% CI: 2.38, -0.43) in adaptive DQ scores, and a 1.08 decrease (95% CI: 2.15, -0.02) in social DQ scores, among which BCIPP, bis (1, 3-dichloro-2-propyl) phosphate (BDCIPP) and DnBP were the main contributors. CONCLUSION: Prenatal exposure to a mixture of OPFRs was negatively associated with early infant neurodevelopment, particularly in gross motor, adaptive, and social domains.

Pollution characteristics, sources, and health risks of phthalate esters in ambient air: A daily continuous monitoring study in the central Chinese city of Nanchang.

In recent years, the atmospheric pollution caused by phthalate esters (PAEs) has been increasing due to the widespread use of PAE-containing materials. Existing research on atmospheric PAEs lacks long-term continuous observation and samples from cities in central China. To investigate the pollution characteristics, sources, and health risks of PAEs in the ambient air of a typical city in central China, daily PM2.5 samples were collected in Nanchang from November 2020 to October 2021. In this study, the detection and quantification of six significant PAE contaminants, namely diethyl phthalate (DEP), di-n-butyl phthalate (DnBP), diisobutyl phthalate (DIBP), Di-2-ethylhexyl phthalate (DEHP), di-n-octyl phthalate (DnOP), and diisodecyl phthalate (DIDP), were accomplished using gas chromatography and mass spectrometry. The results revealed that the concentrations of DEP, DnBP, DEHP, and DnOP were relatively high. Higher temperatures promote the volatilization of PAEs, leading to an increase in the gaseous and particulate PAE concentrations in warm seasons and winter pollution scenarios. The results of principal component analysis show that PAEs mainly come from volatile products and polyvinylchloride plastics. Using positive matrix factorization analysis, it is shown that these two sources contribute 67.0% and 33.0% in atmosphere PAEs, respectively. Seasonally, the contribution of volatile products to both gaseous and particulate PAEs substantially increases during warm seasons. The residents in Nanchang exposed to PAEs have a negligible non-cancer risk and a potential low cancer risk. During the warm seasons, more PAEs are emitted into the air, which will increase the toxicity of PAEs and their impact on human health.

Evaluating the risk of phthalate and non-phthalate plasticizers in dust samples from 100 Japanese houses.

Phthalates are widely used as plasticizer and associated with various health issues. Recently, non-phthalate plasticizers are replacing phthalates; however, the exposure to these substances and the risk in Japan is unclear. In this study, we assessed the concentrations of phthalates, non-phthalate plasticizers, and phthalate degradation products in house dust and determined their respective exposure risks via oral and dermal routes. Twelve phthalates, seven non-phthalate plasticizers, and two degradation products were determined in the house dust obtained from 100 Japanese homes. The median concentration of di(2-ethylhexyl) phthalate (DEHP), accounting for 85 % of the total concentration of phthalates and non-phthalate plasticizers detected in this study, was 2.1 × 103 µg/g of dust. Apart from DEHP, diisononyl phthalate (DINP) and di(2-ethylhexyl) terephthalate (DEHT) were the most abundant in the house dust, accounting for 6.2 % (median: 1.7 × 102 µg/g of dust) and 6.1 % (median: 1.7 × 102 µg/g of dust) of the total concentrations, respectively. DEHP and DEHT concentrations in house dust were higher in apartment and small houses (floor area: ≤30 m2 or 31-60 m2 for DEHP and 31-60 m2 for DEHT) than in detached and large houses (floor area: ≥121 m2). Conversely, di-n-butyl phthalate (DnBP) concentrations were significantly higher in detached and large houses (floor area: ≥121 m2) than in apartment and small houses (floor area: ≤30 m2). The total hazard quotient (HQ), using the maximum concentration in house dust, revealed that oral and dermal exposure to house dust was 1.3 × 10-6-0.11 for adults (all substances) and 1.6 × 10-5-2.2 × 10-2 for preschool children (except for DnBP and DEHP), suggesting no risk. The HQs for DnBP and DEHP exposure via house dust for preschool children using the maximum values were 0.46 and 1.2, and 6.0 × 10-3 and 0.18 using the median values, indicating that risk of DEHP exposure should be exhaustively determined by considering other exposure routes that were not evaluated in this study, such as diet.

[Accumulation Characteristics and Sources of PAEs in Agricultural Soils in Gansu Province].

In order to understand the composition and accumulation characteristics of phthalates esters (PAEs) in agricultural soils in Gansu province, a total of 41 soil samples from four agricultural soils in Gansu province were collected, and the content of six PAEs compounds was analyzed using a gas chromatography-single quadrupole mass spectrometer (GC-MS). The results showed that the average value of PAEs compounds in agricultural soils in Gansu province was 432.4 µg·kg-1. The detection rates of DMP, DEP, DnBP, DEHP, and DNOP in the soil were 100%, and BBP was not detected. The order of the average value of PAEs content in the four agricultural soils in Gansu province was:greenhouse>farmland (open field)>forest>grassland. The exceeding rates of dibutyl phthalate (DnBP), dimethyl phthalate (DMP), and dimethyl phthalate (DEP) were 94%, 28%, and 27%, and the remaining three did not exceed the standard. The composition of PAEs in different agricultural soils was different due to their different sources. DEHP and DnBP components in the six different PAEs monomers accounted for a higher proportion and were the main pollutants of PAEs in agricultural soils in Gansu province. In this study, the contents of soil PAEs and DEHP were significantly positively correlated with the residual amount of mulch film in the farmland (P<0.05). In general, the content of soil PAEs in the Hexi area of Gansu province was significantly higher than that in the Longdong area.

Investigating mitochondria-immune responses in zebrafish, Danio rerio (Hamilton, 1822): A case study with the herbicide dinoseb.

The dinitrophenol herbicide dinoseb is an uncoupler of mitochondrial oxidative phosphorylation (OXPHOS). Studies in fish demonstrate impaired OXPHOS is associated with altered immune system responses and locomotor activity in fish. The objective of this study was to determine the effect of dinoseb on zebrafish (Danio rerio) during early stages of development. We measured oxygen consumption rates of embryos, transcripts related to OXPHOS, growth, and the immune system (cytokines and immune-signaling transcripts), and locomotor activity. We hypothesized that OXPHOS of fish would be impaired in vivo, leading to altered basal immune system expression and locomotor activity. Oxidative respiration assessments in embryos revealed that dinoseb decreased both mean basal respiration and oligomycin-induced ATP-linked respiration. Expression levels of cytochrome c oxidase complex IV, 3-hydroxyacyl-COA dehydrogenase and superoxide dismutase 1 were decreased in larvae following exposure to dinoseb while succinate dehydrogenase complex flavoprotein subunit A, insulin growth factor 1 (igf1) and igf2a mRNA were increased in abundance. Immune-related transcripts chemokine (C-X-C motif) ligand 1 and matrix metallopeptidase 9 (MMP-9) were decreased in expression levels while toll-like receptor 5a and 5b were increased in expression. In addition, a visual motor response test was conducted on both 6 and 7 dpf larvae to determine if dinoseb impaired locomotor activity. Dinoseb decreased locomotor activity in 7 dpf larvae but not 6 dpf. This study improves knowledge of toxicity mechanisms for dinoseb in early stages of fish development and demonstrates that mitochondrial toxicants may disrupt immune signaling in zebrafish.

Airborne phthalates in indoor environment: Partition state and influential built environmental conditions.

Exposure to phthalates has recently become a major public health concern. The information of indoor airborne phthalates and their air-particle partition in real indoor environmental condition is still limited. In this study, the gas- and PM2.5-concentrations of 7 phthalates in 40 residences were concurrently measured in summer and winter. The major phthalates (median concentration in the summer and winter, respectively) in indoor air were DMP (2442.3 and 2403.4 ng/m3), DiBP (801.0 and 640.0 ng/m3) and DnBP (5173.2 and 1379.6 ng/m3), whereas the major phthalates in PM2.5 were DiBP (1055.1 and 585.9 ng/m3) and DnBP (1658.5 and 1517.0 ng/m3) and DEHP (215.1 and 344.9 ng/m3). Air-PM2.5 partition coefficients (Kp) of DiBP, DnBP and DEHP were calculated: the summer and winter median values (m3/µg) were 0.053 and 0.011 for DiBP, 0.010 and 0.004 for DnBP, 0.021 and 0.025 for DEHP, respectively. Air-PM2.5 partition of DiBP and DnBP approached equilibrium, while that of DEHP did not reach equilibrium in either season. The impacts of built environmental conditions on phthalate concentrations were characterized. Elevated temperature resulted in accumulation of airborne phthalates. Higher air humidity led to more water absorption of aerosols in summer, facilitated mass transfer of phthalates from air to PM2.5, and resulted in greater Kp of DiBP and DnBP in the summer. Any factors such as proximity to local traffic highway and indoor smoking activities, which can increase indoor PM2.5 concentrations, resulted in significantly higher airborne phthalate concentrations. Improving ventilation was not an effective measure to reduce indoor airborne phthalate concentrations.

A mitochondrial uncoupler prodrug protects dopaminergic neurons and improves functional outcome in a mouse model of Parkinson's disease.

Dopaminergic neuronal cell loss in the substantia nigra is responsible for the motor symptoms that are the clinical hallmark of Parkinson's disease (PD). As of yet there are no treatments that slow or prevent the degeneration of dopaminergic neurons in PD patients. Here we tested the hypothesis that dopaminergic neurons can be protected by treatment with the mitochondrial uncoupling agent 2,4-dinitrophenol (DNP) and the novel DNP prodrug MP201. We found that mice treated with low doses of DNP and MP201 were protected against motor dysfunction and dopamine neuron loss in the 6-hydroxydopamine PD model, with MP201 being more efficacious than DNP. Amelioration of motor deficits and dopamine neuron loss by MP201 treatment was associated with reductions in microglial and astrocyte activation and neuroinflammation. These preclinical findings suggest the potential application of mitochondrial uncoupling agents such as MP201 as disease-modifying therapies for PD.

Disease modifying mitochondrial uncouplers, MP101, and a slow release ProDrug, MP201, in models of Multiple Sclerosis.

Mitochondrial dysfunction is thought to be involved in the pathogenesis of MS and here we tested if brain penetrant mitochondrial uncouplers, DNP (MP101) and a novel prodrug of DNP (MP201), have the pharmacology to suppress demyelination and axonal loss in two independent models of MS by modulating the entire organelle's physiology. First, the gold standard EAE mouse model for MS was evaluated by daily oral treatment Day 7-21 with either MP101 or MP201 post-immunization. Both MP101/MP201 significantly suppressed progression of paralysis with limited infiltration of inflammatory cells. Strikingly, although mitochondrial uncouplers do increase energy expenditure even at the low doses provided here, they paradoxically preserved body weight at all doses in comparison to wasting in advanced paralysis of the placebos. Second, the effects of the compounds on suppressing inflammation were also evaluated in the cuprizone model, independent of the immune system. MP101/MP201 had a striking effect preserving both myelination and protecting the axons, in comparison to the placebos where both were destroyed. Both MP101/MP201 induced a significant and sustained increase in neurotrophin, BDNF, in the spinal cords. Both MP101/MP201 suppressed the expression of inflammatory cytokines including IL-1ß, TNF-α and iNOS. Results indicate that MP101/MP201 may be a "disease modifying" treatment for MS by specifically modulating mitochondrial physiology. This would be a completely novel treatment for MS, targeting the mitochondria directly using a unique platform, mitochondrial uncouplers, that initially act non-genomically based upon biophysics, but cascades into cellular remodeling, neuroprotection and pro-survival. Clinical Phase I testing of MP101 in Normal Healthy Volunteers (NHV) is currently underway allowing for the potential to subsequently evaluate translation in MS patients and other insidious diseases, at expected weight neutral doses.

Detection of picramic acid and picramate in henné products by NMR Spectroscopy.

Painting and body art are increasing their utilisation as well as their cultural impact, since piercing and tattoos are expanding social phenomena, involving many young people. However, the utilised materials often enter the market with insufficient control and several cases of skin damages are reported. Safety of the utilised products must be ensured by adequate quality controls which must be easily made, rapid, low cost, clear and persuasive. The method here reported, regards the analysis on the possible presence of picramic acid in the ethyl acetate extracts of commercial henné powders by NMR Spectroscopy. In the proton spectrum, three sets of peaks could be detected, corresponding to the three classes of makers resonances: hennosides, typical markers of Lawsonia inermis, the henné plant; picramic acid or picramate; fatty acids. In particular, the set of signals corresponding to hennosides can be used as markers of the utilisation of the correct raw material of henné.

Kinetics of Glutathione Depletion and Antioxidant Gene Expression as Indicators of Chemical Modes of Action Assessed in Vitro in Mouse Hepatocytes with Enhanced Glutathione Synthesis.

Here we report a vertically integrated in vitro - in silico study that aims to elucidate the molecular initiating events involved in the induction of oxidative stress (OS) by seven diverse chemicals (cumene hydroperoxide, t-butyl hydroperoxide, hydroquinone, t-butyl hydroquinone, bisphenol A, Dinoseb, and perfluorooctanoic acid). To that end, we probe the relationship between chemical properties, cell viability, glutathione (GSH) depletion, and antioxidant gene expression. Concentration-dependent effects on cell viability were assessed by MTT assay in two Hepa-1 derived mouse liver cell lines: a control plasmid vector transfected cell line (Hepa-V), and a cell line with increased glutamate-cysteine ligase (GCL) activity and GSH content (CR17). Changes to intracellular GSH content and mRNA expression levels for the Nrf2-driven antioxidant genes Gclc, Gclm, heme oxygenase-1 ( Hmox1), and NADPH quinone oxidoreductase-1 ( Nqo1) were monitored after sublethal exposure to the chemicals. In silico models of covalent and redox reactivity were used to rationalize differences in activity of quinones and peroxides. Our findings show CR17 cells were generally more resistant to chemical toxicity and showed markedly attenuated induction of OS biomarkers; however, differences in viability effects between the two cell lines were not the same for all chemicals. The results highlight the vital role of GSH in protecting against oxidative stress-inducing chemicals as well as the importance of probing molecular initiating events in order to identify chemicals with lower potential to cause oxidative stress.

Substrate-Induced Self-Assembly of Cooperative Catalysts.

Dissipative self-assembly processes in nature rely on chemical fuels that activate proteins for assembly through the formation of a noncovalent complex. The catalytic activity of the assemblies causes fuel degradation, resulting in the formation of an assembly in a high-energy, out-of-equilibrium state. Herein, we apply this concept to a synthetic system and demonstrate that a substrate can induce the formation of vesicular assemblies, which act as cooperative catalysts for cleavage of the same substrate.

Synthesis and characterization of FeIII(µ-OH)ZnII complexes: effects of a second coordination sphere and increase in the chelate ring size on the hydrolysis of a phosphate diester and DNA.

The synthesis and characterization of three ligands and their respective heterobinuclear FeIIIZnII complexes were carried out, with the goal of mimicking the active site of purple acid phosphatases (PAPs). The ligand 2-hydroxy-3-(((2-hydroxy-5-methyl-3-(((2-(pyridin-2-yl)ethyl)(pyridin-2-ylmethyl)amino)methyl)benzyl)(pyridin-2ylmethyl)amino)methyl)-5-methylbenzaldehyde (H2L2) was synthesized and its complex (FeIIIZnIIL2) was used as a basis for comparison with similar complexes previously published in the literature. Subsequent modifications were conducted in the aldehyde group, where 1,2-ethanediamine and 1,4-diaminobutane were used as side chain derivatives. The compounds FeIIIZnIIL2 (1), FeIIIZnIIL2-et (2) and FeIIIZnIIL2-but (3) were characterized by spectroscopic methods (infrared and UV-Vis) and ESI-MS spectrometry. Theoretical calculations were performed to provide insights into the complex structures with FeIIIZnII structures. The hydrolytic activity was analyzed both with the model substrate 2,4-BDNPP and with DNA catalyzed by complexes 1, 2 and 3.

Distribution, lipid-bilayer affinity and kinetics of the metabolic effects of dinoseb in the liver.

Dinoseb is a highly toxic pesticide of the dinitrophenol group. Its use has been restricted, but it can still be found in soils and waters in addition to being a component of related pesticides that, after ingestion by humans or animals, can originate the compound by enzymatic hydrolysis. As most dinitrophenols, dinoseb uncouples oxidative phosphorylation. In this study, distribution, lipid bilayer affinity and kinetics of the metabolic effects of dinoseb were investigated, using mainly the isolated perfused rat liver, but also isolated mitochondria and molecular dynamics simulations. Dinoseb presented high affinity for the hydrophobic region of the lipid bilayers, with a partition coefficient of 3.75×104 between the hydrophobic and hydrophilic phases. Due to this high affinity for the cellular membranes dinoseb underwent flow-limited distribution in the liver. Transformation was slow but uptake into the liver space was very pronounced. For an extracellular concentration of 10µM, the equilibrium intracellular concentration was equal to 438.7µM. In general dinoseb stimulated catabolism and inhibited anabolism. Half-maximal stimulation of oxygen uptake in the whole liver occurred at concentrations (2.8-5.8µM) at least ten times above those in isolated mitochondria (0.28µM). Gluconeogenesis and ureagenesis were half-maximally inhibited at concentrations between 3.04 and 5.97µM. The ATP levels were diminished, but differently in livers from fed and fasted rats. Dinoseb disrupts metabolism in a complex way at concentrations well above its uncoupling action in isolated mitochondria, but still at concentrations that are low enough to be dangerous to animals and humans even at sub-lethal doses.

Effect of oxidation and catalytic reduction of trace organic contaminants on their activated carbon adsorption.

The combination of ozonation and activated carbon (AC) adsorption is an established technology for removal of trace organic contaminants (TrOCs). In contrast to oxidation, reduction of TrOCs has recently gained attention as well, however less attention has gone to the combination of reduction with AC adsorption. In addition, no literature has compared the removal behavior of reduction vs. ozonation by-products by AC. In this study, the effect of pre-ozonation vs pre-catalytic reduction on the AC adsorption efficiency of five TrOCs and their by-products was compared. All compounds were susceptible to oxidation and reduction, however the catalytic reductive treatment proved to be a slower reaction than ozonation. New oxidation products were identified for dinoseb and new reduction products were identified for carbamazepine, bromoxynil and dinoseb. In terms of compatibility with AC adsorption, the influence of the oxidative and reductive pretreatments proved to be compound dependent. Oxidation products of bromoxynil and diatrizoic acid adsorbed better than their parent TrOCs, but oxidation products of atrazine, carbamazepine and dinoseb showed a decreased adsorption. The reductive pre-treatment showed an enhanced AC adsorption for dinoseb and a major enhancement for diatrizoic acid. For atrazine and bromoxynil, no clear influence on adsorption was noted, while for carbamazepine, the reductive pretreatment resulted in a decreased AC affinity. It may thus be concluded that when targeting mixtures of TrOCs, a trade-off will undoubtedly have to be made towards overall reactivity and removal of the different constituents, since no single treatment proves to be superior to the other.

In vitro neurotoxic hazard characterisation of dinitrophenolic herbicides.

Dinitrophenolic compounds are powerful toxicants with a long history of use in agriculture and industry. While (high) human exposure levels are not uncommon, in particular for agricultural workers during the spraying season, the neurotoxic mechanism(s) that underlie the human health effects are largely unknown. We therefore investigated the in vitro effects of two dinitrophenolic herbicides (DNOC and dinoseb) on a battery of neurotoxicity endpoints in (dopaminergic) rat PC12 cells. Cell viability, mitochondrial activity, oxidative stress and caspase activation were assessed using fluorescence-based bioassays (CFDA, alamar Blue, H2DCFDA and Ac-DEVD-AMC, respectively), whereas changes in intracellular [Ca(2+)]i were assessed using single-cell fluorescence microscopy with Fura-2AM. The combined results demonstrate that exposure to both DNOC and dinoseb is linked to calcium release from the endoplasmic reticulum and activation of caspase-mediated apoptotic pathways. In subsequent experiments, immunofluorescent labelling with specific antibodies was used to determine changes in intracellular α-synuclein levels, demonstrating that both DNOC and dinoseb increase levels of intracellular α-synuclein. The combined results indicate that in vitro exposure to DNOC and dinoseb activates pathways that are not only involved in acute neurotoxicity but also in long-term effects as seen in neurodegeneration.

Reactivity of Imidazole Derivatives toward Phosphate Triester in DMSO/Water Mixtures: A Comprehensive Study on the Solvent Effect.

Many imidazole (IMZ) derivatives of pharmaceutical interest, which are potentially catalytic in dephosphorylation reactions, are soluble solely in mixtures of water and organic solvent. In order to understand these poorly explored reactions and properly compare them, a thorough study related to solvent effects for the analogous spontaneous reaction and with common IMZ derivatives is necessary, which is lacking in the literature. Herein, we report a quantitative solvent effect analysis in DMSO/water mixtures for (i) the hydrolysis reaction of diethyl 2,4-dinitrophenylphosphate (DEDNPP) and (ii) the nucleophilic reaction of IMZ and 1-methylimidazole (MEI) with DEDNPP. The solvent effect was fitted satisfactorily with multiple regression analysis, correlating the obtained second-order rate constants with solvent parameters such as acidity, basicity, and polarity/polarizability from Catalán's scale. The contribution of these parameters can be taken into account to elucidate the reactivity in these media. Interestingly, IMZ is more reactive than MEI in DMSO, compared to water alone, which is attributed to the availability of hydrogen-bond formation. Nuclear magnetic resonance spectroscopy ((1)H, (13)C, and (31)P), mass spectrometry, thermodynamic analysis, and density functional theory calculations were carried out to corroborate the proposed nucleophilic mechanism.

Phosphoester hydrolysis: the incoming substrate turns the bridging hydroxido nucleophile into a terminal one.

Identifying the active nucleophile in hydrolysis reactions catalyzed by binuclear hydrolases is a recurrent problem and a matter of intense debate. We report on the phosphate ester hydrolysis by a Fe(III)Fe(II) complex of a binucleating ligand. This complex presents activities in the range of those observed for similar biomimetic compounds in the literature. The specific electronic properties of the Fe(III)Fe(II) complex allowed us to use (1)H NMR and Mössbauer spectroscopies to investigate the nature of the various species present in the solution in the pH range of 5-10. Both techniques showed that the hydrolysis activity is associated to a µ-hydroxido Fe(III)Fe(II) species. Further (1)H NMR experiments show that binding of anions or the substrate changes this bonding mode suggesting that a terminal hydroxide is the likely nucleophile in these hydrolysis reactions. This view is further supported by the structure determination of the hydrolysis product.

[The developoment of total complement activity assay based on complement-dependent immune liposome lysis].

BACKGROUND: The purpose of work was development of a fast and reproduced procedure for measurement of the total complement activity (TCA) in human or animal blood serum. MATERIALS AND METHODS: Steady at storage liposomes preparations, which surface sensitized 2,4-DNP haptens, and the internal volume contains calceine or sulforhodamine 101 are obtained. Complement-dependent immune lysis of liposomes at presence of the anti-2,4-DNP immunoglobulines and complement preparations from animals are investigated. RESULTS: It is shown that the degree of liposomes immune lysis depends on complement concentration in a wide range that can be used for definition of TCA level. Research of blood sera from patients has revealed correlation (r = 0.793) between data received with the help of liposome immunolytic systems, and the data of nephelometric analysis with application of suspension sheep erythrocytes. CONCLUSION: The method allows to define total complement activity in blood serum in 15 minutes without separation of reaction components. This might be useful for measurement TCA level at patients with various diseases and realization of scientific researches.

Degradation kinetics and chloropicrin formation during aqueous chlorination of dinoseb.

The kinetics of chlorination of dinoseb and the corresponding formation of disinfection by-products (DBPs) were studied between pH 4 and 9 at room temperature (25±1°C). The reactivity shows a minimum at pH 9, a maximum at pH 4 and a medium at neutral conditions. pH profile of the apparent second-order rate constant of the reaction of dinoseb with chlorine was modeled considering the elementary reactions of HOCl with dinoseb species and an acid-catalyzed reaction. The predominant reactions at near neutral pH were the reactions of HOCl with the two species of dinoseb. The rate constants of 2.0 (±0.8)×10(4)M(-2)s(-1), 3.3 (±0.6) and 0.5 (±0.1)M(-1)s(-1) were determined for the acid-catalyzed reaction, HOCl reacted with dinoseb and dinoseb(-), respectively. The main degradation by-products of the dinoseb formed during chlorination have been separated and identified by GC-MS with liquid-liquid extraction sample pretreatment. Six volatile and semi-volatile DBPs were identified in the chlorination products, including chloroform (CF), monochloroacetone, chloropicrin (TCNM), 1,1-dichloro-2-methy-butane, 1,2-dichloro-2-methy-butane, 1-chloro-3-methy-pentanone. A proposed degradation pathway of dinoseb during chlorination was then given. TCNM and CF formation potential during chlorination of dinoseb reached as high as 0.077 and 0.097µMµM(-1) dinoseb under the traditional condition (pH=7 and Cl2/C=2). Their yields varied with Cl2/C, pH and time. The maximum yields of TCNM appeared at molar ratio as Cl2/C=1 and pH 3, while the maximum of CF appeared at molar ratio as Cl2/C=4 and pH 7. [TCNM]/[CF] decreased with reaction time and increased solution pH.