Short-term test for the toxicogenomic assessment of ecotoxic modes of action in Myriophyllum spicatum

In environmental risk assessment of substances, the 14-day growth inhibition test following OECD test guideline 239 is employed to assess toxicity in the macrophyte Myriophyllum spicatum. Currently, this test evaluates physiological parameters and does not allow the identification of the mode of action (MoA) by which adverse effects are induced. However, for an improved ecotoxicity assessment of substances, knowledge about their ecotoxic MoA in non-target organisms is required. It has previously been suggested that the identification of gene expression changes can contribute to MoA identification. Therefore, we developed a shortened three-day assay for M. spicatum including the transcriptomic assessment of global gene expression changes and applied this assay to two model substances, the herbicide and photosynthesis inhibitor bentazone and the pharmaceutical and HMG-CoA reductase inhibitor atorvastatin. Due to the lack of a reference genome for M. spicatum we performed a de novo transcriptome assembly followed by a functional annotation to use the toxicogenomic results for MoA discrimination. The gene expression changes induced by low effect concentrations of these substances were used to identify differentially expressed genes (DEGs) and impaired biological functions for the respective MoA. We observed both concentration-dependent numbers and differentiated patterns of DEGs for both substances. While bentazone impaired genes involved in the response to reactive oxygen species as well as light response, and also genes involved in developmental processes, atorvastatin exposure led to a differential regulation of genes related to brassinosteroid response as well as potential metabolic shifts between the mevalonate and methyl erythritol 4-phosphate pathway. Based on these responses, we identified biomarker candidates for the assessment of MoA in M. spicatum. Utilizing the shortened assay developed in this study, the investigation of the identified biomarker candidates may contribute to the development of future MoA-specific screening approaches in the ecotoxicological hazard prediction using aquatic non-standard model organisms.

Zero-waste preparation of mixed oxides for submicromolar sensing of Bentazone pesticide

Necessity of having simple selective and robust methods for the analysis of environmentally relevant chemicals stimulates the development of new approaches to material preparation. Electrochemical sensing using electroactive substrates has proved efficient in the analysis of a wide range of pesticides and is widely used as a routine analytical method. Recently, mixed oxides showed promising electrocatalytic activity toward hazardous substrates. Prevalence of wet chemical methods in the synthesis of mixed oxides creates a methodological obstacle and inconvenience for their wide utilization. In this work we challenged the common preparation of mixed oxides with simple powder mixing and developed an electrode for bentazone detection with satisfactory detection limit (0.4 μM), recovery rate (≈104%), and a broad linearity range (1-45 μM). The proposed modified carbon paste electrode is highly selective and can be used for determination of bentazone in presence of interfering ions in water samples.

Discovery of a Novel Benzothiadiazine-Based Selective Aldose Reductase Inhibitor as Potential Therapy for Diabetic Peripheral Neuropathy

Aldose reductase 2 (ALR2), an activated enzyme in the polyol pathway by hyperglycemia, has long been recognized as one of the most promising targets for complications of diabetes, especially in diabetic peripheral neuropathy (DPN). However, many of the ALR2 inhibitors have shown serious side effects due to poor selectivity over aldehyde reductase (ALR1). Herein, we describe the discovery of a series of benzothiadiazine acetic acid derivatives as potent and selective inhibitors against ALR2 and evaluation of their anti-DPN activities in vivo. Compound 15c, carrying a carbonyl group at the 3-position of the thiadiazine ring, showed high potent inhibition against ALR2 (IC50 = 33.19 nmol/L) and ∼16,109-fold selectivity for ALR2 over ALR1. Cytotoxicity assays ensured the primary biosafety of 15c. Further pharmacokinetic assay in rats indicated that 15c had a good pharmacokinetic feature (t1/2 = 5.60 h, area under the plasma concentration time curve [AUC(0-t)] = 598.57 ± 216.5 μg/mL * h), which was superior to epalrestat (t1/2 = 2.23 h, AUC[0-t] = 20.43 ± 3.7 μg/mL * h). Finally, in a streptozotocin-induced diabetic rat model, 15c significantly increased the nerve conduction velocities of impaired sensory and motor nerves, achieved potent inhibition of d-sorbitol production in the sciatic nerves, and significantly increased the paw withdrawal mechanical threshold. By combining the above investigations, we propose that 15c might represent a promising lead compound for the discovery of an antidiabetic peripheral neuropathy drug.

ARTICLE HIGHLIGHTS

Investigating the impacts of airborne dust on herbicide performance on Amaranthus retroflexus

Dust pollution poses environmental hazards, affecting agriculture through reduced sunlight exposure, photosynthesis, crop yields, and food security. This study explores the interference of dust pollution on herbicide efficacy to control weeds in a semi-arid region. In a factorial experiment conducted in 2019 and replicated in 2020, the interaction of dust and various herbicide applications, including bentazon, sulfosulfuron, tribenuron-methyl, aminopyralid + florasulam, foramsulfuron + iodosulfuron + thiencarbazone, 2,4-D + MCPA, and acetochlor, in controlling Amaranthus retroflexus L. were assessed. Dust induced a 9.2% reduction in the total chlorophyll content of A. retroflexus, while herbicide application independently led to a 67.5% decrease. Contrary to expectations, herbicides performed better in dust, except bentazon, which caused a 28% drop in plant height and a 29% decrease in total biomass compared to non-dust conditions. Both herbicides and dust exerted suppressive effects on A. retroflexus's leaf and stem weights and overall biomass. Despite dust presence, tribenuron-methyl (95.8%), aminopyralid + florasulam (95.7%), sulfosulfuron (96.5%), and foramsulfuron + iodosulfuron + thiencarbazone (97.8%) effectively controlled A. retroflexus. These findings indicate that dust's effect on herbicide efficacy is herbicide-dependent but except bentazon, dust generally increased herbicide efficacy and amplified the control of A. retroflexus.

National Assessment of Long-Term Groundwater Response to Pesticide Regulation

Quantitative assessments of long-term, national-scale responses of groundwater quality to pesticide applications are essential to evaluate the effectiveness of pesticide regulations. Retardation time in the unsaturated zone (R_u) was estimated for selected herbicides (atrazine, simazine, and bentazon) and degradation products (desethylatrazine (DEA), desisopropylatrazine (DIA), desethyldesisopropylatrazine (DEIA), and BAM) using a multidecadal time series of groundwater solute chemistry (∼30 years) and herbicide sales (∼60 years). The sampling year was converted to recharge year using groundwater age. Then, R_u was estimated using a cross-correlation analysis of the sales and the frequencies of detection and exceedance of the drinking water standard (0.1 μg/L) of each selected compound. The results showed no retardation of the highly polar, thus mobile, parent compounds (i.e., bentazon), while R_u of the moderately polar compounds (i.e., simazine) was about a decade, and their degradation products showed even longer R_u. The temporal trends of the degradation products did not mirror those of the sale data, which were attributed to the various sale periods of the parent compounds, sorption of the parent compounds, and complex degradation pathways. The longer R_u in clayey/organic sediments than in sandy sediments further confirmed the role of soil-specific retardation as an important factor to consider in groundwater protection.

Investigation of resistance mechanisms to bentazone in multiple resistant Amaranthus retroflexus populations

Redroot amaranth (Amaranthus retroflexus L.) is a noxious weed that affects soybean production in China. Experiments were conducted to determine the molecular basis of resistance to bentazone. Whole-plant dose-response experiments showed that two populations (R1 and R2) exhibited resistance to bentazone with resistance indices of 9.01 and 6.85, respectively. Sequencing of the psbA gene revealed no amino acid substitution in the two populations. qRT-PCR analysis verified that psbA gene expression in R1 and R2 populations was increased significantly after treatment with bentazone, which was 3-fold and 5-fold higher than that in S1 and S2 populations, respectively. The P450 inhibitor malathion significantly reduced the level of resistance in the R1 and R2 populations when used prior to bentazone treatment. The R1 population exhibited multiple resistance to thifensulfuron-methyl and lactofen, caused by target site mutations (Asp-376-Glu in ALS, Arg-128-Gly in PPO2). In conclusion, increased gene expression of the psbA gene and enhanced herbicide metabolism seem to be the basis of resistance to bentazone in these A. retroflexus populations.

Bentazone in water and human urine in Wuhan, central China: exposure assessment

Bentazone is a widely used post-emergence herbicide, while no data was available on its concentrations in tap water from China and in urine among the general population. It was determined in the source (Wuhan section of the Yangtze River watershed), treated, and tap water (n = 20, 20, and 170, respectively) in different seasons (2019) in Wuhan, central China. Also, urine samples (n = 38) collected from healthy adults in Wuhan (September 2020) were analyzed to characterize its urinary concentration. Bentazone was detected in all the source and treated water samples. Its concentrations in the source water in July were higher than those in February (median: 17.9 ng/L vs. 2.86 ng/L) (p < 0.05). It cannot be removed efficiently (27.8-27.9%) by conventional drinking water treatment using NaClO, but it can be efficiently removed by using chlorine dioxide or ozone combined with activated carbon. Bentazone was frequently detected (detection frequency: 96.3%) in 160 tap water samples (underwent conventional treatment) (median: 1.95 ng/L, range: <0.02-47.0 ng/L), while it was not detectable in tap water samples that underwent ozone combined with activated carbon. Seasonal variations were found, with the lowest median concentration (ng/L) in April (0.46) and the highest in July (17.6). In addition, bentazone was frequently (92.1%) detected in human urine samples (median: 0.02 ng/mL; range: < 0.01-0.11 ng/mL). The estimated daily intake of bentazone based on its median concentration in tap water (0.04 ng/kg-body weight [bw]/day) accounted for approximately 8% of that based on the median urinary concentration (0.48 ng/kg-bw/day). This is the first time to characterize its occurrence in drinking water from China and its occurrence in the urine of the general population.

Automation in quantifying phenoxy herbicides and bentazon in surface water and groundwater using novel solid phase extraction and liquid chromatography tandem mass spectrometry

The occurrence of phenoxy herbicides is a financial and regulatory concern for drinking water treatment plants. This paper presents a new method of quantification for nine phenoxy-acids and bentazon in different water samples using liquid chromatography tandem mass spectrometry (LC-MS/MS). The method is based on an automated solid phase extraction (SPE) process that applied hydrophilic modified polystyrene and divinylbenzene cartridges at low pH (<2.0). Main advantages of the presented method include the reduced consumption of organic solvent in extraction and the fully automated sample pre-concentration. The method is thus more environmentally-friendly. In the quantification step, five stable isotopically labelled analogues were used as internal standards to account for the losses during sample preparation and to calibrate the ion source response under the mass spectrometric detection. The method was optimized in terms of sample preparation and subsequent LC-MS/MS separation to obtain reliable measurement of the analyte concentration during real sample analysis. The method quantification limit was between 1.5 and 10.0 ng/L for target compounds in surface water and groundwater samples. The method was validated at three fortification levels between 10.0 and 1000 ng/L, and the results showed fit-for-purpose recovery with appropriate precision at low concentration levels. The method was also utilized to analyse thirty-two actual water samples from different sources. Forty percent of the analysed samples contained detectable level of herbicides, ranging from 1.91 to 40.5 ng/L. The concentrations of targeted herbicides in our study were comparable to those found in water samples in other regions of world.

Photocatalytic removal of bentazon by copper doped zinc oxide nanorods: Reaction pathways and toxicity studies

In this study, bentazon herbicide was degraded photocatalytically by copper doped zinc oxide nanorods fabricated by using a facile co-precipitation method. The crystal structure, morphology, surface composition, functional groups on the surface and valence state of the nanorods were investigated by XRD, SEM-EDX, FTIR, and XPS material characterization techniques. Environmental parameters including solution pH, catalyst dose, bentazon concentration, purging gases, H₂O₂ content, organic compound type and reusability affecting the rate of photocatalytic degradation of bentazon were evaluated. Under the optimal conditions, [Bentazon]₀ = 20 mg L^-1, Cu-ZnO loading = 0.5 g L^-1, H₂O₂ = 2 mM, pH = 7 and in the presence of oxygen gas, 100% of the herbicide was removed within 60 min. By raising bentazon concentration (10-50 mg L^-1), k_obs decreased to values between 0.14 and 0.006 min^-1 and the calculated electrical energy per order (E_Eo) increased from 38.16 to 727.27 (kWh m^-3), respectively. The degradation removal of the herbicide using the UV/Cu-ZnO method (98.28%) was higher than that of the UV/ZnO method (32.14%) process. Interestingly, the photocatalytic performances in the first and fifth reuse cycles during catalyst recyclability tests were found to be similar. Generally, the efficacy of the method in the decomposition of bentazon in drinking water (78.95%) and actual sewage (46.77%) declined because of the presence of other anions due to their role as a scavenger of photogenerated reactive species. Intermediate products in the photocatalytic degradation of bentazon identified by gas chromatography/mass spectrometry (GC/MS) analysis were 2-amino-N-isopropyl-benzamide, 2-amino-benzoic acid, N-isopropyl-2-nitro-benzamide, and acids such as pentenedioic acid, oxalic acid and propenoic acid. Furthermore, the main mechanism for the photocatalytic removal of bentazon was determined to be via attack by hydroxyl radicals (^•OH). The results of toxicity in the photocatalytic removal of bentazon by D. magna showed LC₅₀ and toxicity unit (TU) 48 h equal to 46.10 and 9.56 vol percent.

THE EFFECT OF ADEMOL ON THE DNA FRAGMENTATION OF CEREBRAL CORTEX CELLS IN RATS WITH EXPERIMENTAL TRAUMATIC BRAIN INJURY

THE AIM OF THE STUDY

To determine the effect of Ademol on the deoxyribonucleic acid (DNA) fragmentation of the cerebral cortex cells (apoptosis) of rats with traumatic brain injury (TBI).

MATERIALS AND METHODS

An experimental model of severe trauma was created in male rats using an air pistol. The therapeutic effect of Ademol in TBI was evaluated at a dose of 2 mg/kg intravenously at intervals of 2 t/d for 8 days. As a drug for the control group we used 0.9% NaCl at a dose of 2 ml/kg, and as a comparison drug - amantadine sulfate at a dose of 5 mg/kg. On day 8 after TBI and decapitation of animals, the parts of the cerebral cortex were taken to assess further DNA fragmentation in cells by the flow cytometry method.

RESULTS AND CONCLUSIONS

The post-traumatic period of model TBI in rats is accompanied by a probable increase in the level of DNA fragmentation in the nucleus of cerebral cortex cells on the 8th day of the experiment. By the antiapoptotic effect in conditions of post-traumatic brain injury, Ademol solution therapy was significantly better than the infusion of 0.9% NaCl and amantadine sulfate at an average of 46.2 and 27.2%, respectively (p<0.05).

Remediation of bentazone contaminated water by Trametes versicolor: Characterization, identification of transformation products, and implementation in a trickle-bed reactor under non-sterile conditions

Bentazone, an herbicide widely applied in rice and cereal crops, is widespread in the aquatic environment. This study evaluated the capacity of Trametes versicolor to remove bentazone from water. The fungus was able to completely remove bentazone after three days at Erlenmeyer-scale incubation. Both laccase and cytochrome P450 enzymatic systems were involved in bentazone degradation. A total of 19 transformation products (TPs) were identified to be formed during the process. The reactions involved in their formation included hydroxylations, oxidations, methylations, N-nitrosation, and dimerization. A laccase mediated radical mechanism was proposed for TP formation. In light of the results obtained at the Erlenmeyer scale, a trickle-bed reactor with T. versicolor immobilized on pine wood chips was set up to evaluate its stability during bentazone removal under non-sterile conditions. After 30 days of sequencing batch operation, an average bentazone removal of 48% was obtained, with a considerable contribution of adsorption onto the lignocellulosic support material. Bacterial contamination, which is the bottleneck in the implementation of fungal bioreactors, was successfully addressed by this particular system according to its maintained performance. This research is a pioneering step forward to the implementation of fungal bioremediation on a real scale.

Geographical and temporal assessment of the photochemical decontamination potential of river waters from agrochemicals: A first application to the Piedmont region (NW Italy)

This work shows the potential of using photochemical modelling to assess the river-water ability to photodegrade agrochemicals on a geographic and temporal scale. The case of flowing water requires different data treatment compared to more stationary water bodies (e.g., lakes), but it could allow for the identification of particularly vulnerable environments. Five pesticides were considered here, and the photodegradation rate followed the order bentazon > isoproturon > dimethomorph ∼ chlortoluron > atrazine. The modelled photodegradation kinetics was particularly fast in the river Po, which receives significant input of agricultural nitrate from groundwater and features higher steady-state [^•OH] than most other rivers in the region. The fact that the Po eventually collects all river waters in Piedmont is positive, from the point of view of comprehensive photodegradation of pesticides. However, this paradoxical situation of agricultural pollution (nitrate) helping fight pollution from the same source (pesticides) has two important limitations: (i) when compared to the parent compounds, some intermediates deriving from ^•OH reactions are either more harmful (N-formyl derivatives of phenylureas), or about as harmful (desethyl atrazine); (ii) banned atrazine is no longer sprayed over fields during the plant growth season, but it reaches surface waters from legacy groundwater inputs. The latter are operational also during winter, when photochemistry is least active. Therefore, photochemistry might not ensure considerable attenuation of atrazine during wintertime. Overall, bentazon would be the safest among the studied pesticides because of fast degradation by direct photolysis, and of low ecotoxicological impact of its phototransformation intermediates.

Neonicotinoids, fipronil, chlorpyrifos, carbendazim, chlorotriazines, chlorophenoxy herbicides, bentazon, and selected pesticide transformation products in surface water and drinking water from northern Vietnam

Studies on the occurrence of emerging pesticides in surface and drinking water in Vietnam are limited. In this study, lake water (n = 7), river water (n = 1), tap water (n = 46), and bottled water (n = 3) collected from Hanoi and other four provinces in northern Vietnam were analyzed for selected pesticides (including insecticides such as neonicotinoids, fipronil, and chlorpyrifos; fungicide carbendazim; herbicides such as atrazine, terbuthylazine, simazine, 2,4-dichlorophenoxyacetic acid, 2-methyl-4-chlorophenoxyacetic acid, and bentazon) and some of their degradates by liquid chromatography-tandem mass spectrometry. Carbendazim (median: 86.7 ng/L) and triazines (49.3 ng/L) were the major pesticides found in lake water samples, followed by neonicotinoids and their degradation products (15.1 ng/L), chlorpyrifos and its degradate (13.4 ng/L), fipronil and its degradates (3.76 ng/L), chlorophenoxy acid herbicides (2.10 ng/L), and bentazon (0.62 ng/L). Triazines (164 ng/L) were the major pesticides in river water. Higher concentrations (median: 39.3 ng/L; range: 1.20-127) of selected pesticides were found in tap water from Hanoi than those from four other provinces studied (5.49 ng/L; 4.73-66.8 ng/L). Bottled water samples collected from Hanoi contained lower concentrations of pesticide residues (median: 3.54 ng/L, range: 2.18-8.09) than those of tap water samples. The calculated risks from pesticide exposure through ingestion of tap water by the general populations were low. However, fipronil concentrations in lake water exceeded the benchmark value recommended for freshwater in the United States or the Netherlands. Degradation of acetamiprid into desmethyl-acetamiprid was found in lake water.

Identification of a cytochrome P450 hydroxylase, CYP81E22, as a causative gene for the high sensitivity of soybean to herbicide bentazon

KEY MESSAGE

A frame shift invoked by a single-base deletion in the gene encoding a cytochrome P450 hydroxylase, CYP81E22, causes the loss of bentazon detoxification function in soybean. Bentazon is an effective herbicide in soybean cultivation applied at post-emergence stages for control of several broadleaf weeds. However, some soybean cultivars are highly sensitive to bentazon and are killed upon application. In this study, the gene related to the high sensitivity of soybean cultivars to bentazon was mapped to chromosome 16, and its location was narrowed down to a 257-kb region where three cytochrome P450 genes were located. In these genes, a single-base deletion of cytosine was detected in the coding region of Glyma.16G149300, CYP81E22, at + 1465 bp downstream from the translation start codon, leading to a frame shift in the open reading frame and creating a premature stop codon. This stop codon resulted in the loss of more than half of the P450, and consequently, the remaining molecule failed to form a functioning protein. This single-base deletion was common among the highly sensitive cultivars screened from the soybean mini-core collection and other previously reported highly sensitive cultivars. Furthermore, we screened plant lines from the targeting-induced local lesions in genomes library of the soybean cultivar Enrei based on a modelled 3D structure of CYP81E22. The lines with mutations in Glyma.16G149300 were highly sensitive to bentazon, which provides strong evidence that Glyma.16G149300 is the gene responsible for high sensitivity to bentazon.

Layered platforms of Ti4O7 as flow-through anodes for intensifying the electro-oxidation of bentazon

In this study, we prepared Ti₄O₇ porous electrodes with continuous layered structures characterized by different layer-to-layer distance (from 2 to 10 μm) but the same total void fraction (88-90%), to modulate the electrodes' permeability and the volumetric electrochemical surface area (from 90 to 840 cm² cm^-3). These platforms were evaluated as anodes in the electro-oxidation (EO) of bentazon in a three-electrode cell under galvanostatic conditions, operated both in traditional batch (TB) or batch recycle flow-through (BRFT) modes. The performance was significantly enhanced when the liquid was recirculated through the lamellar structure of the electrodes. In BRFT mode, the electrode interlayer gap was found to be a key factor to control the bentazon and total organic carbon (TOC) conversions. For the best conditions evaluated (BRFT, 10 μm-interlayered Ti₄O₇ electrodes with a volumetric surface area of 90 cm² cm^-3), the effect of the applied current (1 or 3 mA) and liquid flow rate (10, 12 or 14 mL. min^-1) was investigated. Specific energy consumption (SEC) values were estimated to reveal the performance of each of the EO treatments from an energetic point of view. The use of 10 μm-interlayered Ti₄O₇ electrodes at 1 mA in BRFT mode at a flow rate of 14 mL min^-1 showed the best results, yielding 85% bentazon removal, 57% mineralization and SEC values of 0.006 kWh.g_TOC^-1 after 6 h of treatment. This contribution highlights the use of layered Ti₄O₇ electrodes as a promising strategy for intensifying EO processes, pointing to a trade-off between the accessibility to the internal electrode structure and the volumetric electrode surface area to enhance the contact between the target molecules and the hydroxyl radicals physisorbed on the electrode surface, while minimizing simultaneously the energy requirements.

EVALUATION OF THE EFFECT OF ADEMOL ON THE DYNAMICS OF NEURON-SPECIFIC ENOLASE IN TRAUMATIC BRAIN INJURY IN RATS

The great hopes of modern medicine for neuroprotective therapy have stimulated scientists around the world to actively search for new effective means of influencing the pathophysiological cascades of the development of neuronal damage. Aim. To evaluate the effect of the use of the adamantane derivative 1-adamantylethyloxa-3-morpholino-2-propanol hydrochloride (ademol) compared with amantadine sulfate and 0.9% NaCl solution on the activity dynamics of neuron-specific enolase in rats with acute traumatic brain injury (TBI) . The therapeutic effect of ademol in experimental traumatic brain injury was evaluated using a dose of 2 mg/kg (i/v) every 12 hours for 8 days. The pseudo-operated animals and the control group received a 0.9% NaCl solution at a dose of 2 ml/kg i/v, and the comparison group received amantadine sulfate at a dose of 5 mg/kg in the same mode. To determine the effectiveness of the studied drugs in brain injury, the level of neuron-specific enolase (NSE) was used. The course infusion in rats with TBI of solutions of ademol (2 mg/kg) and amantadine sulfate (5 mg/kg) during the 8 days of the TBI model, significantly reduced the increase in the NSE level in animals of the control pathology group by an average of 52.1 and 38.2%. Thus, the results obtained indicate that when using ademol at a dose of 2 mg/kg i/v and amantadine sulfate (5 mg/kg i/v), powerful neurocytoprotective properties appear against the background of a model head injury. Moreover, the neuroprotective effect of ademol manifested itself more clearly, since in terms of the ability to prevent the increase in NSE levels, it significantly dominated the reference drug by an average of 22.5%.

Adsorption of bentazone and imazapyc from water by using functionalized silica: Experimental and computational analysis

In this study, silica and functionalized silica materials (3-aminopropyl and 3-mercapto derivatives) were successfully used for the removal of the pesticides bentazone and imazapyc from aqueous solutions. Adsorbent materials were characterized by BET isotherms and FT-IR spectroscopy (confirming the functionalization), and their equilibrium adsorption capacity was evaluated at different ionic strengths. It is observed that the maximum adsorption capacities decrease in the order 3-aminopropyl-derivative > silica >3-mercaptopropyl derivative. An increase in ionic strength produces an enhancement in the removal of pesticides. All isotherms are Ib-type and follow the Langmuir model, suggesting a monolayer physical adsorption process.

Influence of electrolysis conditions on the treatment of herbicide bentazon using artificial UVA radiation and sunlight. Identification of oxidation products

The main objective of this work is to demonstrate the viability of solar photoelectro-Fenton (SPEF) process to degrade pesticides in urban wastewater matrix, selecting the herbicide bentazon as a model molecule. In order to provide a correct assessment of the role of the different oxidants and catalysts involved, bentazon was comparatively treated by anodic oxidation with electrogenerated H₂O₂ (AO-H₂O₂), electro-Fenton (EF) and UVA-assisted EF (i.e., PEF) processes as well, either in sulfate or chloride media. Trials were made in a stirred tank reactor with an air-diffusion cathode and a boron-doped diamond (BDD), RuO₂-based or Pt anode. In chlorinated matrices, the herbicide disappeared more rapidly using a RuO₂-based anode because of the generated active chlorine. The best mineralization performance was always obtained using BDD due to its higher oxidation power, which allowed the complete destruction of refractory chloroderivatives. A concentration of 0.50 mM Fe²⁺ was found optimal to catalyze Fenton's reaction, largely enhancing the mineralization process under the action of OH. Among photo-assisted treatments, sunlight was proven superior to a UVA lamp to promote the photolysis of intermediates, owing to its greater UV irradiance and contribution of visible photons, although PEF also allowed achieving a large mineralization. In all cases, bentazon decay obeyed a pseudo-first-order kinetics. SPEF treatment in urban wastewater using BDD at only 16.6 mA cm^-2 yielded 63.2% mineralization. A thorough, original reaction pathway for bentazon degradation is proposed, including seven non-chlorinated aromatics, sixteen chloroaromatics and two chloroaliphatics identified by GC-MS, most of them not previously reported in literature. Ion-exclusion HPLC allowed the detection of seven short-chain linear carboxylic acids.

How do thiazide and thiazide-like diuretics lower blood pressure?

Thiazide diuretics are widely used for the treatment of hypertension, but the mechanism by which these drugs lower blood pressure in the long term remains unknown. This article reviews current knowledge about the hypotensive actions of thiazides and thiazide-like diuretics and discusses possible mechanisms of action.

Medicaid Prescriber Compliance with Joint National Committee VI Hypertension Treatment Guidelines

BACKGROUND:

Since the early 1970s, the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC) has been tasked with the formulation of national guidelines for the management of hypertension. These were significantly changed in 1993 with publication of JNC-5. JNC-6 kept many basic treatment recommendations (i.e., initiation of therapy with a thiazide diuretic or β-blocker), partly in response to the low adoption rate of the treatment recommendations of JNC-5.

OBJECTIVE:

To describe single-drug outpatient therapy of hypertension and temporally correlate these therapies with the publication of JNC-5 and JNC-6.

METHODS:

The electronic records of randomly selected New York State Medicaid recipients without hospitalization who had a diagnosis of hypertension and who were receiving only 1 antihypertensive medication were analyzed for 1994, 1997, and 1999. This analysis identified the medications selected for monotherapy of hypertension and compared these therapies with JNC recommendations. The analysis was correlated to patient comorbidities to further account for provider selection of a non—first-line agent.

RESULTS:

In 1994, angiotensin-converting enzyme (ACE) inhibitors and calcium-channel blockers accounted for 69% of therapies, with 67.5% of these patients having no JNC-recognized individualizing consideration for their use. In 1999, the combined use of ACE inhibitors and calcium-channel blockers accounted for over 65% of all single-drug therapy; 60% of these patients had no individualizing considerations. Also, in 1999, 47.7% of all patients appeared to be receiving antihypertensive therapies that are not compliant with JNC recommendations.

CONCLUSIONS:

Single-drug therapy of hypertension in a nonhospitalized New York state Medicaid population from 1994 through 1999 did not closely follow JNC recommendations for the single-agent treatment of hypertension.

Hypercalciuria: diagnosis and management

Hypercalciuria may be due to increased bone resorption, increased intestinal absorption, increased renal excretion or due to hypophosphatemia. Examination of the serum for calcium, phosphorus, parathyroid hormone and 1,25(OH)2D3, and of the urine for calcium, phosphorus and cyclic AMP will help arrive at the correct diagnosis. Therapies specific for each type of hypercalciuria are available and can be used. However, a more simplified diagnostic approach, and the use of thiazide diuretics for therapy, will usually suffice in the majority of patients.

Iatrogenic Hypercalcemia Due to Vitamin D3Ointment (1,24(OH)2D3) Combined with Thiazide Diuretics in a Case of Psoriasis

Tacalcitol is a synthetic vitamin D3 analogue developed for topical treatment of inflammatory skin diseases such as psoriasis. Hypercalcemia has not been previously reported during treatment with topical tacalcitol. We experienced a male patient with psoriasis and hypertension whose conditions were treated with tacalcitol ointment and thiazide, respectively, resulting in hypercalciuria and hypercalcemia. After initiation of topical vitamin D3 ointment (20 micro g/g of tacalcitol) 10 g/day for the skin lesions, both the serum level of calcium and urinary excretion of calcium increased gradually. On day 28 of the treatment, his serum calcium levels had reached 3.55 mmol/l, and his urinary calcium excretion had also increased from 0.008 g/day to 0.475 g/day. The tacalcitol treatment was terminated, seven days later, the serum calcium level had returned to the reference range without any specific treatment. The present case is the first report of hypercalcemia induced by vitamin D3 ointment and thiazide simultaneously.

Herbicide residues and nitrate concentration in tubers of table potatoes

This study examined Wiking-cultivar table potato tubers in a field experiment conducted between 2002 and 2004 using a rye complex soil. The experimental factors included (a) two methods of tillage, including traditional and simplified, as well as (b) seven methods of cultivation with the use of herbicides as follows: 1, control without herbicides; 2, Plateen 41.5 WG; 3, Plateen 41.5 WG + Fusilade Forte 150 EC; 4, Plateen 41.5 WG + Fusilade Forte 150 EC + adjuvant Atpolan 80 EC; 5, Barox 460 SL; 6, Barox 460 SL + Fusilade Forte 150 EC; and 7, Barox 460 SL + Fusilade Forte 150 EC + adjuvant Atpolan 80 EC. Determination of residues was performed using high-performance liquid and gas chromatography. Only trace quantities of bentazone (Barox 460 SL) were found in potato tubers, amounts that fell below the maximum residue limit (MRL). The nitrate content of potato tubers was determined using a nitrate ion-selective electrode and silver chloride reference electrode. The nitrate content in fresh matter of unpeeled and peeled tubers depended significantly only on weather conditions in the years of study. In contrast, agrotechnical procedures such as methods of tillage and cultivation did not significantly affect potato tuber nitrate content.

ALLHAT: a critical assessment

The ALLHAT study has attracted considerable attention in the media and in the research community, partly due to the study's unexpected and controversial conclusions. However, the study has several serious shortcomings. The primary end-points in ALLHAT were negative and the conclusions are based entirely on secondary end-points and subgroup analyses. Moreover, there is good reason for skepticism concerning the findings on heart failure in ALLHAT, because of ambiguity in the diagnosis, lack of information on blood pressure and absence of a "washout" period. The study design was severely flawed and does not reflect clinical reality. Also, blood pressure differences between groups severely complicate interpretation. From a patient perspective in ALLHAT, there are drug safety concerns with the thiazides, as there was evidence of excess diabetes development. The ALLHAT results are difficult to generalize and have limited relevance in European settings. Thus, the ALLHAT study suffers from several major shortcomings and there is a huge body of evidence that contradicts the ALLHAT interpretations.

Angiotensin‐receptor blockers and diuretics—Advantages of combination

Surveys have shown that in as many as half of patients treated for hypertension, blood pressure (BP) is not controlled to target levels; many more persons have undertreated hypertension. Uncontrolled hypertension is a serious risk factor for cardiovascular events such as stroke, heart failure, myocardial infarction and target-organ diseases. Studies have shown that strict BP control significantly reduces the occurrence of these cardiovascular outcomes, in the majority of patients, effective BP control requires two or more antihypertensive agents. The combination of an angiotensin-receptor blocker (ARB) and a thiazide diuretic is appealing, since these agents have complimentary effects on BP reduction, left ventricular hypertrophy and progression of renal diseases. In addition, this combination provide excellent tolerability. The combination of an ARB and a thiazide diuretic may be of particular value in patient populations who tend to have poor BP control on monotherapy, or have additional cardiovascular or renal risk factors.

Impairment of glucose metabolism during treatment with antihypertensive drugs

A reversible deterioration of the oral glucose tolerance has been reported in subjects with initially impaired glucose tolerance when starting to take oral diuretics. This does not seem to be the case in subjects with an initially unimpaired glucose tolerance. A deterioration in the diabetic state is commonly seen when diuretics are given to subjects with clinical diabetes. Our knowledge about the effect of beta-blockers on the glucose tolerance is limited. As for diuretics there seems to be an overrepresentation of diabetics among subjects taking beta-blockers. This overrepresentation can probably be explained by an association between diabetes and disturbances in which diuretics and beta-blockers are commonly used such as arterial hypertension and ischaemic heart disease.

Thiazides and loop-diuretics therapeutic aspects

Thiazides and compounds with similar models of action exert their most important renal effects on the cortical-diluting segment of the nephron, most likely from the peritubular side. In contrast, the most important site of action of loop-diuretics is the luminal side of the ascending part of the diluting segment. The different sites of action explain the clinically proven efficacious combination of thiazides and loop-diuretics in severe cardiac failure. Most thiazides and loop-diuretics are eliminated via renal tubular secretion, which leads to decreased renal clearance in patients with chronic heart failure (CHF) as their renal blood flow is decreased even if glomerular filtration rate (GFR) is maintained. A rational approach to enhance the effects of loop-diuretics is to combine them with drugs that increase renal blood flow, thereby increasing the rate of delivery of the drug to its site of action. Dilutional hyponatremia is an important complication of treatment with diuretics. An efficacious treatment of that condition seems to be a combination of loop-diuretics and ACE-inhibitors. Thiazides decrease the urinary excretion of calcium, while loop-diuretics have the opposite effect. The possibility of loop-diuretic induced osteopenia cannot be ruled out, which should be considered when choosing between thiazides and loop-diuretics for the treatment of mild to moderate CHF.

Potassium maintenance. Potassium supplements or potassium sparing agents

This paper reviews and presents data from a series of studies evaluating the extent of potassium depletion that occurs in various disease states and a comparison of the efficacy of potassium supplementation or potassium sparing diuretics in its correction. Changes in serum potassium levels are common after diuretics but are relatively minor in most people if small doses of diuretics are used. Total body potassium deficit is uncommon in people treated with a diuretic for hypertension and the fall in serum potassium results from alkalosis and a shift of potassium into the cell. Potassium sparing diuretics correct the potassium abnormality more readily than potassium supplements. Evidence is also presented that suggests that a high salt, low potassium diet may be an important cause of hypokalemia in people given diuretics.

Hematological side effects from antihypertensive drugs

To sum up, some hematological side effects are seen after antihypertensive drugs. They are, however, few, usually not severe and furthermore reversible. And so, from the viewpoint of the hematologist, there are no contraindications against antihypertensive treatment. The prevalence of side effects on blood and blood-forming organs from antihypertensive drugs is low. Of certain interest are 1) the tendency of modern diuretics (thiazides) to cause a moderate and reversible thrombocytopenia and 2) the positive antiglobulin reaction (Coomb's test) sometimes seen after alpha-methyldopa therapy and in a few cases causing autoimmune hemolytic anemia. Even though case reports have appeared on leukopenia/agranulocytosis related to almost all drugs used in the treatment of hypertension, none of these drugs seem to be especially prone to cause any damage to leukocytes and/or leukocyte production.

Plasma and skeletal muscle electrolytes in patients on long-term diuretic therapy for arterial hypertension and/or congestive heart failure

Investigations regarding plasma and skeletal muscle electrolytes were carried out in 537 patients on long-term diuretic treatment (greater than 1 year) for arterial hypertension (n = 240) and/or congestive heart failure (n = 297). In both groups there were significant decreases in both plasma and skeletal muscle K and Mg, while the muscle Na values as well as the total and extracellular water content of skeletal muscle were increased.

Interaction of clonidine and labetalol in hypertension

Concomitant administration of the alpha 2-adrenoceptor agonist, clonidine, and the alpha 1- and non-selective beta-adrenoceptor antagonist, labetalol, was studied in 12 hypertensive outpatients treated with thiazide diuretics. Clonidine, 0.15 mg b.i.d., effectively lowered supine, standing and isometric blood pressure values when administered to patients on cyclothiazide, 2.5 mg q.d. Addition of labetalol, 200 mg b.i.d., to the diuretic-clonidine treatment resulted in further reduction of blood pressure at rest both in the supine and standing position. In contrast, during isometric work, addition of labetalol to the diuretic-clonidine regimen did not exhibit the same additive antihypertensive effect. When clonidine was given in a dose of 0.3 mg once daily in the evening and the other two drugs as previously, the same antihypertensive effect was observed in the afternoon. Labetalol did not provoke new side-effects of its own.