Chlorogenic acid mitigates potassium dichromate-induced acute hepato-nephrotoxicity by attenuating the NF-κB signalling pathway.

BACKGROUND: Hexavalent chromium (CrVI) is known to be a potentially hepatotoxic and nephrotoxic contaminant in humans and other animals, whose toxicity is associated with oxidative stress and inflammation. The aim of this study was to evaluate the potential protective effect of chlorogenic acid (CGA), which has known anti-inflammatory and antioxidant effects, on potassium dichromate (PDC)-induced acute hepatotoxicity and nephrotoxicity in rats. METHODS AND RESULTS: Thirty-six Wistar albino rats were treated with CGA (10, 20, or 40 mg/kg, intraperitoneally) and/or PDC (15 mg/kg/day, intraperitoneally) as a single dose. Serum, liver, and kidney tissues were examined biochemically, histopathologically, and immunohistochemically. Compared to the control group, a significant increase in interleukin-6 (IL-6) levels and a significant decrease in serum and renal reduced glutathione (GSH) levels, liver catalase (CAT), tumour necrosis factor-alpha (TNF-α), and interleukin 1ß (IL-1ß) levels were observed in the PDC group. The administration of PDC led to histopathological and immunohistochemical changes in rat liver and kidney tissues. With the administration of CGA, especially at the 10 mg/kg dosage, the above-mentioned parameters approached normal levels. CONCLUSIONS: CGA had antioxidant and anti-inflammatory effects that alleviated PDC-induced acute hepato- and nephrotoxicity.

Simultaneous binding characterization of different chromium speciation to serum albumin.

The binding process between three species of chromium and serum albumin (SA) was investigated, as well as the interaction between K2Cr2O7 and bovine serum albumin (BSA) under coexistence of different chromium forms. CrCl3, K2Cr2O7 and Crpic bound to SA spontaneously through Van der Waals force, and their binding constants were 103-104 M-1 at 298 K, respectively. K2Cr2O7 and Crpic both had strong binding affinity for BSA, and significantly affected the secondary structure of BSA and the microenvironment surrounding amino acid residues. Chromium exhibited a greater fluorescence quenching constant towards HSA than toward BSA, and K2Cr2O7 induced greater conformational changes in human serum albumin (HSA) than in BSA. A weak binding of CrCl3 to BSA had no significant effect on the binding affinity of K2Cr2O7 to BSA. K2Cr2O7 and BSA have a greater binding affinity when coexisting with Crpic, and K2Cr2O7 induces a greater conformational change in BSA.

Potassium dichromate sensitivity presenting as tefillin dermatitis: A retrospective cohort study.

BACKGROUND: Tefillin are a religious article worn by Jewish men during daily prayer. Tefillin dermatitis secondary to potassium dichromate sensitivity is recognised, but data remain sparse. OBJECTIVE: To investigate the prevalence and clinical characteristics of tefillin dermatitis. METHODS: Patients who underwent patch testing with the European baseline series in a tertiary dermatology clinic in 2009-2023 and were diagnosed with tefillin dermatitis were identified by file review and their clinical data recorded. RESULTS: Of 1679 consecutive male patients tested, 25 (1.49%) were diagnosed with tefillin dermatitis, accounting for 15.34% of all potassium-dichromate-positive patients (163/1679). Mean pre-symptomatic duration of tefillin use was 38 ± 16.9 years, and mean follow-up time, 3.1 ± 2.9 years. Patients presented with an eczematous rash on body areas in direct contact with the leather box or straps of the tefillin. An id reaction was noted in 32%, and sensitivity to other leather accessories, in 44%. Fourteen patients (56%) switched to chromate-free tefillin: symptoms resolved completely in 11 (79%) and partially in 2. LIMITATIONS: Retrospective cohort design. CONCLUSION: This is the largest study to date of tefillin dermatitis caused by sensitivity to potassium dichromate used in leather production. Prognosis after switching to chromate-free tefillin was good-to-excellent. Tefillin dermatitis may be more prevalent than previously thought.

Beneficial effects of mate-herb, Ilex paraguariensis St. Hil. against potassium dichromate-induced oxidative stress and nephrotoxicity.

Chimarrão is a typical beverage made from the infusion of dried and ground leaves and stems of Ilex paraguariensis (popularly known as Yerba mate or mate herb) which is widely consumed in parts of South America. The aim of this study was to examine the effects of the chimarrão against nephrotoxicity and oxidative stress induced by the potassium dichromate (PD) salt in male Wistar rats. The experiment lasted 17 days, and in the first 15 days animals ingested a chimarrão infusion or control drinking water and then submitted to an intraperitoneal injection (15 mg/kg) of PD (or saline solution) and euthanized after 48 hr at which time animals still received infusion or drinking water. Blood plasma and 24 hr-urine samples were collected to measure creatinine levels as an estimate of glomerular filtration rate (GFR). Concomitantly oxidative stress was determined in the kidneys as evidenced by levels of carbonyl groups, malondialdehyde (MDA) and antioxidant capacity against peroxyl radicals. Potassium dichromate induced oxidative stress in the kidneys and reduced GFR. Treatment with chimarrão during the 15 days prior to PD injection reduced PD salt-mediated oxidative stress. Further, treatment with post-injection chimarrão to PD-administered rats improved the GFR. Our findings support that the use of the chimarrão beverage may be considered as an important nephroprotective substance.

Development of a microplate-based novel toxicity bioassay using Chlorophyta and Phaeophyceae macroalgae.

Macroalgae are one of the main producers in marine environments. However, only a few toxicity test methods have been established that use reference strains of macroalgae to evaluate the effects of chemicals on the growth and reproduction of macroalgae to monitor water quality. We selected reference strains of Chlorophyta, Ulva aragoënsis; Phaeophyceae, Ectocarpus siliculosus; and wakame, Undaria pinnatifida, as test species to establish a microplate-based method to investigate the toxicity of potassium dichromate, 3,5-dichlorophenol, and two common herbicides (diuron and simazine). We determined the growth of the three macroalgae in their early life stages and during the sporangia formation stage in E. siliculosus under laboratory conditions. We observed that the growth and sporangia formation in these algae were impaired in a dose-dependent manner. Additionally, we investigated the sensitivity of these macroalgae by comparing the toxicity values of toxicants used in this study with those obtained from a database. Compared to other microalgae and plant species, macroalgae showed a relatively high sensitivity to organic compounds, including herbicides. Growth tests using U. aragoënsis and E. siliculosus produced reliable results at 0-32 and 25-32 practical salinity units (PSU), respectively. The tests established in this study could test the toxicity of chemical substances in macroalgae and are thus expected to contribute to a better understanding of the environmental risks of chemical substances on aquatic biota. The tests could be applied to all effluent toxicity tests used for the management of seawater and brackish water quality.

The possible protective role of selenium on the visual cortex of adult albino rat on exposure to potassium dichromate.

The visual cortex is very important in mammals for processing of visual information. Exposure to heavy metals such as potassium dichromate poses serious health threat to human beings. The aim of this work is to study the effect of potassium dichromate on the visual cortex of adult albino rat and also to identify the possibility of selenium as protective agent against toxicity of potassium dichromate. A total number of 40 adult albino rats weighting (200-250) gm were used. They divided into four groups: control group, potassium dichromate received group, potassium dichromate and selenium received group and selenium received group. The rats received treatment for 6 weeks. After 6 weeks, they were sacrificed. The present study showed that potassium dichromate causes degeneration of granular neurons in layer IV and pyramidal neurons in layer V. Morphometric results revealed statistically significant decrease in the number of granule and pyramidal cells in potassium dichromate received group as compared with control group. Most of degenerative changes are improved by selenium.

الدور الوقائي المحتمل للسيلينيوم على القشرة المخية البصرية للفأر الابيض البالغ عند التعرضللدايكرومات البوتاسيومسالي سيد أنور-هالة محمد حسانينقسم التشريح الادمي وعلم الاجنة -كلية الطب البشرى- جامعة اسيوطالقشرة البصرية مهمة جدا في الثدييات لمعالجة المعلومات المرئية. يشكل التعرض للمعادنالثقيلة مثل ثنائي كرومات البوتاسيوم تهديداً صحياً خطيراً للإنسان. الهدف من هذا العمل هودراسة تأثير ثنائي كرومات البوتاسيوم على القشرة البصرية لجرذ ألبينو البالغ وكذلك التعرفعلى إمكانية استخدام السيلينيوم كعامل وقائي ضد سمية ثنائي كرومات البوتاسيوم. تم استخدامجرذ من الجرذان البالغة وزنها (200-250) جرام. تم تقسيمهم إلى 4 مجموعات: المجموعة40الضابطة ، المجموعة المستلمة ثنائي كرومات البوتاسيوم ، المجموعة المستلمة ثاني كروماتالبوتاسيوم والسيلينيوم المجموعة المستلمة سيلينيوم تلقتالفئران العلاج لمدة 6أسابيع. بعد ستة أسابيع تم التضحية بهم. أظهرت الدراسة الحالية أن ثنائي كرومات البوتاسيوميسبب تنكس الخلايا العصبية الحبيبية في الطبقة الرابعة والخلايا العصبية الهرمية في الطبقةالخامسة. أظهرت نتائج القياس المورفومتري انخفاضًا ذا دلالة إحصائية في عدد الخلايا الحبيبيةوالهرمية في المجموعة التي تم تلقيها من ثنائي كرومات البوتاسيوم مقارنة بمجموعة التحكم. يتمتحسين معظم التغييرات التنكسية بواسطة السيلينيوم.[Figure: see text].

Ellagic acid ameliorates hexavalent chromium-induced renal toxicity by attenuating oxidative stress, suppressing TNF-α and protecting mitochondria.

Nephrotoxicity is an important adverse effect of oxidative stress induced by hexavalent chromium [Cr(VI)]. The effect of ellagic acid, a dietary polyphenolic compound with potent antioxidant activity, was investigated in Cr(VI)-induced kidney injury. Six groups of male Wistar rats were treated intragastrically with vehicle or ellagic acid (15 and 30 mg/kg) for 10 days. On day 10, rats received saline or Cr(VI) (K2Cr2O7 15 mg/kg) subcutaneously. Cr(VI) significantly increased kidney weight, affected kidney function assessed by biomarkers in blood and urine (protein, creatinine and urea nitrogen), caused histological changes (tubular injury and glomerular capillary tuft damage), increased markers of oxidative stress and reduced the activity of antioxidant enzymes. In addition, Cr(VI) altered mitochondrial ultrastructure, impaired mitochondrial respiration, increased lipid peroxidation, and inhibited the function of mitochondrial enzymes. Pretreatment with ellagic acid (30 mg/kg) attenuated all the aforementioned alterations. Furthermore, we explored whether ellagic acid might regulate the tumor necrosis factor-alpha (TNF-α)/receptor-interacting protein kinase 3 (RIPK3) pathway, reducing Cr(VI)-induced tubular necrosis. Cr(VI) upregulated both TNF-α and RIPK3, but ellagic acid only decreased TNF-α levels, having no effect on RIPK3 content. Therefore, understanding the mechanisms through which Cr(VI) promotes necroptosis is crucial for future studies, in order to design strategies to mitigate kidney damage. In conclusion, ellagic acid attenuated Cr(VI)-induced renal alterations by preventing oxidative stress, supporting enzymatic activities, suppressing TNF-α, and preserving mitochondrial ultrastructure and function, most likely due to its antioxidant properties.

Occupational contact allergy of construction workers in Greece: Trends during 2009-2018.

BACKGROUND: Recent trends in the sensitization of construction workers show a decrease in potassium dichromate and an increase in epoxy resin sensitization. OBJECTIVES: To present the trends of occupational contact allergy of construction workers in Greece from 2009 to 2018. METHODS: We retrospectively reviewed the files of patients with eczema patch tested in our Contact Dermatitis Clinic who were construction workers. RESULTS: A total of 191 construction workers initially reported contact dermatitis. Of these, 138 had occupation-relevant allergic contact dermatitis (ACD) or irritant contact dermatitis (ICD). All patients were men. After being patch tested, 98 (71.0%) were diagnosed with ACD and 40 with ICD. Median duration of occupation till onset of ACD was 2 years (interquartile range [IQR] 0.8-7). The hands were the most common location for ACD (73.5%), followed by the trunk (39.8%), the legs (38.8%), and the face (11.2%). Of the patients, 74.6% had lesions affecting multiple body sites. Potassium dichromate (67%) was the most frequent allergen, followed by thiuram mix (37.4%) and cobalt chloride (31.8%). Sensitization to epoxy resins was lower (12.1%). CONCLUSION: The sensitization pattern of Greek construction workers does not follow the trends in Central or Northern Europe, rather sharing attributes with less industrialized countries.

HMGA2 mediates Cr (VI)-induced metabolic reprogramming through binding to mitochondrial D-Loop region.

Hexavalent chromium [Cr (VI)] exists environmentally and occupationally. It has been shown to pose a carcinogenic hazard in certain occupations. This study was to investigate the role of high mobility group A2 (HMGA2) in Cr (VI)-induced metabolism reprogramming from oxidative phosphorylation (OXPHOS) to glycolysis in A549 and HELF cells. First, knockdown of HMGA2 by siHMGA2 significantly attenuated Cr (VI)-reduced expression of OXPHOS-related proteins (COX IV and ND1) and mitochondrial mass, indicating that HMGA2 was involved in Cr (VI)-reduced OXPHOS. Overexpression of HMGA2 by transfection of HMGA2-DNA plasmids reduced the expression of COX IV, ND1 and mitochondrial mass, suggesting the negative role of HMGA2 in OXPHOS. Secondly, both CCCP, the inhibitor of mitochondrial function, and the ER stress inhibitor, 4-phenylbutyric acid (4-PBA), decreased the level of HMGA2, indicating that the interaction of mitochondrial dysfunction and ER stress resulted in Cr (VI)-induced HMGA2 expression. Further study demonstrated that ER stress/HMGA2 axis mediated the metabolism rewiring from OXPHOS to aerobic glycolysis. Notably, Cr (VI) induced the accumulation of HMGA2 proteins in mitochondria and ChIP assay demonstrated that HMGA2 proteins could bind to D-loop region of mitochondrial DNA (mtDNA), which provided the proof for HMGA2-modulating OXPHOS. Taken together, our results suggested that the interaction of mitochondria and ER stress-enhanced HMGA2 played an important role in Cr (VI)-induced metabolic reprogramming from OXPHOS to glycolysis by binding directly to D-loop region of mtDNA. This work informs on the potential mode of action for Cr (VI)-induced tumors and builds on growing evidence regarding the contribution of cellular metabolic disruption contributing to carcinogenicity.

Patch test results in patients with suspected contact allergy to shoes: Retrospective IVDK data analysis 2009-2018.

BACKGROUND: Allergic contact dermatitis caused by shoes is common and new relevant allergens have been identified. OBJECTIVES: To investigate the pattern of type IV sensitization in patients with suspected allergic contact dermatitis of the feet related to shoes as a presumed culprit trigger. METHODS: Retrospective analysis of data of the Information Network of Departments of Dermatology (IVDK), 2009-2018. RESULTS: Six hundred twenty-five patients with presumed shoe dermatitis were identified in a cohort of 119 417 patients. Compared to patients with suspected contact sensitization from other allergen sources (n = 118 792), study group patients were more frequently sensitized to potassium dichromate (10.8% vs 3.5%), colophony (7.2% vs 3.7%), mercaptobenzothiazole (MBT; 4.0% vs 0.6%), mercapto mix (4.6% vs 0.6%), and p-tert-butylphenol formaldehyde resin (1.6% vs 0.5%). Sensitizations to urea formaldehyde resin, melamine formaldehyde resin, glutaraldehyde, tricresyl phosphate, and phenyl glycidylether were rare. Moreover, reactions to compounds in the leather or textile dyes test series were scarce. CONCLUSION: A distinct sensitization pattern was observed in patients with suspected allergy to shoe materials. Although substances with low sensitization rates should be removed from the leather and shoe patch test series, novel potential allergens should be added.

Oral administration of ammonium metavanadate and potassium dichromate distorts the inflammatory reaction induced by turpentine oil injection in male rats.

Heavy metal pollution is rapidly increasing in the environment. It has been shown that exposure to vanadium and chromium is able to alter the immune response. Nevertheless, the mechanisms by which these metal pollutants mediate their immunomodulatory effects are not completely understood. Herein, we examined the effect of ammonium metavanadate and potassium dichromate on the development of an inflammatory response caused by subcutaneous injection of turpentine oil. We demonstrated that pretreatment of rats with ammonium metavanadate and potassium dichromate for two weeks prior to initiation of the inflammatory response resulted in a wider zone of necrosis surrounding the site of inflammation. The acute inflammatory process in the combined model was characterized by elevated serum levels of IL-10 and decreased serum levels of IL-6 as compared to rats not treated with ammonium metavanadate and potassium dichromate. Ammonium metavanadate and potassium dichromate administration induced a decrease in the proportion of splenic His48HighCD11b/c+ myeloid cells accompanied by a reduced infiltration of the wound with neutrophils. Further analysis showed decreased proportions of CD3+CD4+IFNγ+ and CD3+CD4+IL-4+ T cells in the rats with combined model as compared to inflamed rats not treated with ammonium metavanadate and potassium dichromate. The data suggest that consumption of vanadium and chromium compounds disrupts the inflammatory response through an altered balance of pro- and anti-inflammatory cytokines and inhibition of effector T cell activation and neutrophil expansion.

Luteolin mitigates potassium dichromate-induced nephrotoxicity, cardiotoxicity and genotoxicity through modulation of Kim-1/Nrf2 signaling pathways.

Environmental and occupational exposure to chromium compounds has become potential aetiologic agent for kidney disease with excessive generation of free radicals, apoptosis, and inflammatory. These pathophysiologic mechanisms of potassium dichromate (K2 Cr2 O7 ) have been well correlated with nephrotoxicity and cardiotoxicity. The cardioprotective and nephroprotective effects of Luteolin, a known potent antioxidant were evaluated in this study with 40 healthy rats in four experimental groups: Group A (normal saline), Groups B (30 mg/kg K2 Cr2 O7 ), Group C (Luteolin 100 mg/kg and K2 Cr2 O7 30 mg/kg), and Group D (Luteolin 200 mg/kg and K2 Cr2 O7 30 mg/kg), respectively. Markers of antioxidant defense system, oxidative stress, blood pressure and micronucleated polychromatic erythrocytes (MnPEs), immunohistochemistry of Kidney, injury molecule (Kim-1), nuclear factor erythroid 2-related factor 2 (Nrf2), and cardiac troponin I were determined. Administration of K2 Cr2 O7 increased blood pressure parameters in systolic, diastolic and mean arterial blood pressures, markers of oxidative stress, and frequency of micronucleated polychromatic erythrocytes, together with reduction in serum nitric oxide level. Renal Kim-1 and cardiac troponin I expressions were higher, but lower expressions of renal and cardiac Nrf2 were recorded with immunohistochemical analysis. Pre-treatment with Luteolin restored blood pressure parameters, with concomitant reduction in oxidative stress indicators, augmented antioxidant mechanisms and serum Nitric oxide level, lowered the expressions of Kim-1, cardiac troponin I and up-regulated of both cardiac and renal Nrf2, reduced the frequency of micronucleated polychromatic erythrocytes. Taken together, this study therefore demonstrates the cardioprotective, nephro protective and antigenotoxic effects of Luteolin through antioxidantive and radical scavenging mechanisms.

Ipomoea staphylina Attenuates Potassium Dichromate-Induced Nephrotoxicity in Wistar Rats via Antioxidant and Antiapoptotic Effects.

Occupational and environmental exposure to chromium compounds leads to nephrotoxicity to humans and animals due to the overproduction of ROS. Our study was aimed to demonstrate the shielding effect of hydroethanolic extract of Ipomoea staphylina (HEIS) bark on male Wistar rats challenged with potassium dichromate (K2Cr2O7). Division of animals was done in 4 groups' viz., normal control, K2Cr2O7 control, K2Cr2O7+HEIS (100 mg/kg), and K2Cr2O7+HEIS (200 mg/kg). Except for the normal control group, other groups were challenged with a single dose (subcutaneous) of K2Cr2O7 (15 mg/kg) and then treated with HEIS (100 and 200 mg/kg) for 1 week. It was observed that animals treated with K2Cr2O7 showed a notable increase in serum creatinine, blood urea, and BUN and dwindles in protein level. These changes were significantly reversed after a 1-week treatment with HEIS (100 and 200 mg/kg). Moreover, HEIS (100 and 200 mg/kg) showed a remarkable improvement in the activity of antioxidant enzymes (GPx, CAT, and SOD) and decreased the levels of TNF-α and IL-1ß in the kidney. Furthermore, treatment with HEIS (100 and 200 mg/kg) notably decreased the activity of caspase-3 and improved the level of HO-1 especially in the K2Cr2O7+ HEIS (200 mg/kg) group. Also, the histopathological study of the kidney supported the protective effects of HEIS. Hence, HEIS bark holds a notable protective effect against K2Cr2O7-induced nephrotoxicity in rats.

A high-throughput screening method for improved R-2-(4-hydroxyphenoxy)propionic acid biosynthesis.

R-2-(4-hydroxyphenoxy)propionic acid (R-HPPA) is a key intermediate of the enantiomerically pure phenoxypropionic acid herbicides. R-HPPA could be biosynthesized through selective introduction of a hydroxyl group (-OH) into the substrate R-2-phenoxypropionic acid (R-PPA) at C-4 position, facilitated by microorganisms with hydroxylases. In this study, an efficient high-throughput screening method for improved R-HPPA biosynthesis through microbial hydroxylation was developed. As a hydroxylated aromatic product, R-HPPA could be oxidized by oxidant potassium dichromate to form brown-colored quinone-type compound. The concentration of R-HPPA can be quantified according to the absorbance of the colored compound at a suitable wavelength of 570 nm; and the R-HPPA biosynthetic capability of microorganism strains could also be rapidly evaluated. After optimization of the assay conditions, the high-throughput screening method was successfully used in identification of Beauveria bassiana mutants with enhanced R-HPPA biosynthesis capacity. A positive mutant C-7 with high tolerance to 20 g/L R-PPA was rapidly selected from 1920 mutants. The biomass and R-HPPA titer were 12.5- and 38.19-fold higher compared with the original strain at 20 g/L R-PPA. This high-throughput screening method developed in this work could also be a potential tool for screening strains producing other important phenolic compounds.

Experimental patch testing with chromium-coated materials.

BACKGROUND: Chromium coatings on metal alloys can be decorative, and prevent corrosion and metal ion release. We recently showed that handling of a chromium-containing disc resulted in chromium deposition on the skin. OBJECTIVES: To examine patch test reactivity to chromium-coated discs. METHODS: We included 15 patients: 10 chromium-allergic patients, and 5 patients without chromium allergy. All were patch tested with potassium dichromate, cobalt chloride, nickel sulfate, and nine different metallic discs. The chromium-allergic patients were also patch tested with serial dilutions of potassium dichromate. RESULTS: Positive/weaker reactions were observed to disc B (1 of 10), disc C (1 of 10), and disc D, disc E, and disc I (4 of 10 each). As no controls reacted to any of the discs, the weak reactions indicate allergic reactions. Positive patch test reactions to 1770 ppm chromium(VI) in the serial dilutions of potassium dichromate were observed in 7 of 10 patients. When the case group was narrowed down to include only the patients with a current positive patch test reaction to potassium dichromate, elicitation of dermatitis by both chromium(III) and chromium(VI) discs was observed in 4 of 7 of patients. CONCLUSIONS: Many of the patients reacted to both chromium(III) and chromium(VI) surfaces. Our results indicate that both chromium(VI) and chromium(III) pose a risk to chromium-allergic patients.

Comparing reliabilities of strip and conventional patch testing.

BACKGROUND: The standardized protocol for performing the strip patch test has proven to be valid, but evidence on its reliability is still missing. OBJECTIVE: To estimate the parallel-test reliability of the strip patch test as compared with the conventional patch test. METHODS: In this multicentre, prospective, randomized, investigator-blinded reliability study, 132 subjects were enrolled. Simultaneous duplicate strip and conventional patch tests were performed with the Finn Chambers® on Scanpor® tape test system and the patch test preparations nickel sulfate 5% pet., potassium dichromate 0.5% pet., and lanolin alcohol 30% pet. Reliability was estimated by the use of Cohen's kappa coefficient. RESULTS: Parallel-test reliability values of the three standard patch test preparations turned out to be acceptable, with slight advantages for the strip patch test. The differences in reliability were 9% (95%CI: -8% to 26%) for nickel sulfate and 23% (95%CI: -16% to 63%) for potassium dichromate, both favouring the strip patch test. CONCLUSIONS: The standardized strip patch test method for the detection of allergic contact sensitization in patients with suspected allergic contact dermatitis is reliable. Its application in routine clinical practice can be recommended, especially if the conventional patch test result is presumably false negative.

Automated swimming activity monitor for examining temporal patterns of toxicant effects on individual Daphnia magna.

Aquatic pollutants are often biologically active at low concentrations and impact on biota in combination with other abiotic stressors. Traditional toxicity tests may not detect these effects, and there is a need for sensitive high-throughput methods for detecting sublethal effects. We have evaluated an automated infra-red (IR) light-based monitor for recording the swimming activity of Daphnia magna to establish temporal patterns of toxicant effects on an individual level. Activity was recorded for 48 h and the sensitivity of the monitor was evaluated by exposing D. magna to the reference chemicals K2 Cr2 O7 at 15, 20 and 25 °C and 2,4-dichlorophenol at 20 °C. Significant effects (P < 0.001) of toxicant concentrations, exposure time and incubation temperatures were observed. At 15 °C, the swimming activity remained unchanged for 48 h at sublethal concentrations of K2 Cr2 O7 whereas activity at 20 and 25 °C was more biphasic with decreases in activity occurring after 12-18 h. A similar biphasic pattern was observed after 2,4-dichlorophenol exposure at 20 °C. EC50 values for 2,4-dichlorophenol and K2 Cr2 O7 determined from automated recording of swimming activity showed increasing toxicity with time corresponding to decreases in EC50 of 0.03-0.07 mg l(-1) h(-1) . EC50 values determined after 48 h were comparable or lower than EC50 values based on visual inspection according to ISO 6341. The results demonstrated that the swimming activity monitor is capable of detecting sublethal behavioural effects that are toxicant and temperature dependent. The method allows EC values to be established at different time points and can serve as a high-throughput screening tool in toxicity testing. Copyright © 2015 John Wiley & Sons, Ltd.

Experimental skin deposition of chromium on the hands following handling of samples of leather and metal.

BACKGROUND: Chromium is an important skin sensitizer. Exposure to it has been regulated in cement, and recently in leather. Studies on the deposition of chromium ions on the skin as a result of handling different chromium-containing materials are sparse, but could improve the risk assessment of contact sensitization and allergic contact dermatitis caused by chromium. OBJECTIVES: To determine whether the handling of chromium-containing samples of leather and metal results in the deposition of chromium onto the skin. METHODS: Five healthy volunteers participated. For 30 min, they handled samples of leather and metal known to contain and release chromium. Skin deposition of chromium was assessed with the acid wipe sampling technique. RESULTS: Acid wipe sampling of the participants' fingers showed chromium deposition on the skin in all participants who had been exposed to leather (range 0.01-0.20 µg/cm(2) ) and in 3 of 5 participants after they had manually handled metal discs (range 0.02-0.04 µg/cm(2) ). CONCLUSIONS: We found that samples of leather and metal had the ability to deposit chromium on the skin at significant levels, in spite of a short duration of exposure.

The protective effect of propylthiouracil against hepatotoxicity induced by chromium in adult mice.

Environmental and occupational exposure to chromium compounds, especially hexavalent chromium (Cr(VI)), is widely recognized as potentially hepatotoxic in humans and animals. Its toxicity is associated with overproduction of free radicals, which induces oxidative damage. This study focused on the possible protective effect of propylthiouracil (PTU) against potassium dichromate (K2Cr2O7). Female mice were divided into four groups (groups I-IV) with seven animals in each group. Group I served as a control, which received tap water; group II received K2Cr2O7 alone (75 mg kg(-1) body weight (b.w.)) via drinking water; group III received both K2Cr2O7 via drinking water and PTU by intramuscular injection at a dose 2.5 mg/100 g(-1) b.w. twice a week, and group IV received PTU alone twice a week for 30 days. Exposure of mice to Cr promoted oxidative stress with an increase in malondialdehyde, protein carbonyl, and advanced oxidation protein product levels. Nonenzymatic antioxidants such as glutathione, nonprotein thiol, vitamin C levels and enzymatic antioxidant activities such as glutathione peroxidase and superoxide dismutase were decreased, while catalase activity was increased. Biomarkers of liver injury such as aspartate and alanine transaminases, lactate dehydrogenase activities, bilirubin, albumin, and glucose levels were increased, while triglyceride and cholesterol levels decreased. Coadministration of PTU restored the above-mentioned parameters to near-normal values. The histological findings confirmed the biochemical results.

Clinical profile and quality of life of patients with occupational contact dermatitis from New Delhi, India.

BACKGROUND: Data regarding occupational contact dermatitis (OCD) and its effect on quality of life (QOL) in India are limited. OBJECTIVES/AIMS: To evaluate patients with OCD and record the outcome of treatment. PATIENTS/MATERIALS/METHODS: All patients with OCD were evaluated for severity of disease (by the use of physician global assessment) and its effect on QOL (by use of the Dermatology Life Quality Index) questionnaire) at the first visit and after 3 months of treatment. RESULTS: Among 117 patients with OCD, hand eczema was present in 81.2%. Positive patch test reactions were found in 76%. The most common allergens were Parthenium hysterophorus and potassium dichromate. The most frequent diagnosis was occupational allergic contact dermatitis (OACD) (57%), caused by farming and construction work, followed by occupational irritant contact dermatitis (OICD) (24%), caused by wet work. Severe psychosocial distress was recorded in 62.5% of patients. After 3 months of treatment, 83% improved significantly, and 54% had improvement in QOL. CONCLUSIONS: Farmers were most frequently affected, followed by construction workers and housewives. OACD was found at a higher frequency than OICD. The most frequent allergens were Parthenium hysterophorus in farmers, potassium dichromate in construction workers, and vegetables in housewives. OCD has a significant impact on QOL. Patch testing, in addition to standard treatment, improves the outcome considerably.