Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 23
Filter
1.
Crit Rev Immunol ; 44(3): 37-52, 2024.
Article in English | MEDLINE | ID: mdl-38421704

ABSTRACT

Regulatory T (Treg) cells hold promise for the ultimate cure of immune-mediated diseases. However, how to effectively restore Treg function in patients remains unknown. Previous reports suggest that activated dendritic cells (DCs) de novo synthesize locally high concentrations of 1,25-dihydroxy vitamin D, i.e., the active vitamin D or 1,25(OH)2D by upregulating the expression of 25-hydroxy vitamin D 1α-hydroxylase. Although 1,25(OH)2D has been shown to induce Treg cells, DC-derived 1,25(OH)2D only serves as a checkpoint to ensure well-balanced immune responses. Our animal studies have shown that 1,25(OH)2D requires high concentrations to generate Treg cells, which can cause severe side effects. In addition, our animal studies have also demonstrated that dendritic cells (DCs) overexpressing the 1α-hydroxylase de novo synthesize the effective Treg-inducing 1,25(OH)2D concentrations without causing the primary side effect of hypercalcemia (i.e., high blood calcium levels). This study furthers our previous animal studies and explores the efficacy of the la-hydroxylase-overexpressing DCs in inducing human CD4+FOXP3+regulatory T (Treg) cells. We discovered that the effective Treg-inducing doses of 1,25(OH)2D were within a range. Additionally, our data corroborated that the 1α-hydroxylase-overexpressing DCs synthesized 1,25(OH)2D within this concentration range in vivo, thus facilitating effective Treg cell induction. Moreover, this study demonstrated that 1α-hydroxylase expression levels were pivotal for DCs to induce Treg cells because physiological 25(OH)D levels were sufficient for the engineered but not parental DCs to enhance Treg cell induction. Interestingly, adding non-toxic zinc concentrations significantly augmented the Treg-inducing capacity of the engineered DCs. Our new findings offer a novel therapeutic avenue for immune-mediated human diseases, such as inflammatory bowel disease, type 1 diabetes, and multiple sclerosis, by integrating zinc with the 1α-hydroxylase-overexpressing DCs.


Subject(s)
T-Lymphocytes, Regulatory , Zinc , Animals , Humans , Vitamin D , Mixed Function Oxygenases , Dendritic Cells , Dietary Supplements
2.
J Neurosci Rural Pract ; 14(4): 582-590, 2023.
Article in English | MEDLINE | ID: mdl-38059246

ABSTRACT

Objectives: This study reviews the effect of albumin-induced volume expansion therapy on symptomatic vasospasm and clinical outcome in aneurysmal subarachnoid hemorrhage (aSAH). Materials and Methods: Computer searches carried out from the Scopus, Medline, Embase, Web of Science, the Cochrane Library, and Internet documents; hand searching of medical journals; and review of reference lists. Randomized controlled trials (RCT) and observational studies (OSs) comparing albumin therapy in combination or alone with crystalloid therapy for the treatment of cerebral vasospasm in aSAH were included in the study. Risk-of-bias assessment was conducted using ROB2.0 and ROBINS-I tools for RCTs and Oss, respectively. Results: Out of a total of 1078 searches, one RCT (published in two articles) and one observational (retrospective) study were included for final analysis. In RCT, albumin was used for volume expansion therapy with a baseline crystalloid regime and comparison made between hypervolemic and normovolemic groups and it showed no beneficial effects on symptomatic vasospasm and clinical outcomes based on the Glasgow outcome scale. Furthermore, the use of albumin showed a tendency for sodium retention with lowering of glomerular filtration rate, limiting the amount of total fluid required for targeted central venous pressure values, and thereby avoiding fluid overload manifestations. The retrospective study results between albumin versus non-albumin groups (crystalloids only) supported improved outcomes in the former group with lower in-hospital mortality. Cardiorespiratory complications were equivocal in RCT and increased in non-albumin group in the retrospective study. Risk-of-bias assessment analyses revealed "some concerns" in RCT and "serious" limitation in OS due to its retrospective design. Conclusion: Albumin-induced volume expansion therapy for cerebral vasospasm does not have substantiative evidence to improve cerebral vasospasm and clinical outcomes in aSAH. Studies with well-designed RCTs are required to compare the use of albumin for volume expansion therapy versus standard fluid management using crystalloids to mitigate the scarcity of published data.

3.
Biol Trace Elem Res ; 201(7): 3367-3380, 2023 Jul.
Article in English | MEDLINE | ID: mdl-36068418

ABSTRACT

Copper (Cu) is a heavy metal that is widely used in industries and is also an essential micronutrient for living beings. However, excess Cu is toxic and human exposure to high levels of this metal results in numerous adverse health effects. We have investigated the effect of oral administration of copper chloride (CuCl2), a Cu(II) compound, on various parameters of oxidative stress, cellular metabolism, and DNA integrity in the rat kidney. This was done to delineate the molecular mechanism of Cu(II) toxicity. Adult male rats were randomly divided into five groups. Animals in four CuCl2-treated groups were separately administered single acute oral dose of CuCl2 at 5, 15, 30, and 40 mg/kg body weight. Animals in the fifth group were not given CuCl2 and served as the control. All rats were sacrificed 24 h after the dose of CuCl2 and their kidneys removed. CuCl2 administration led to significant alterations in enzymatic and non-enzymatic parameters of oxidative stress. It changed the activities of metabolic and membrane bound enzymes and also decreased the activities of brush border membrane enzymes. CuCl2 treatment dose-dependently enhanced DNA damage and DNA-protein crosslinking in renal cells, when compared to the control group. The administration of CuCl2 also resulted in marked morphological changes in the kidney, with more prominent alterations at higher doses of CuCl2. These results clearly show that CuCl2 impairs the antioxidant defense system resulting in oxidative damage to the kidney.


Subject(s)
Antioxidants , Copper , Humans , Male , Rats , Animals , Antioxidants/metabolism , Copper/metabolism , Chlorides/pharmacology , Oxidative Stress , Kidney/metabolism , Administration, Oral , DNA Damage
4.
Amino Acids ; 54(1): 33-46, 2022 Jan.
Article in English | MEDLINE | ID: mdl-34993628

ABSTRACT

Sodium chlorate (NaClO3) is a common non-selective herbicide that is also used in paper and pulp mills and is produced as a by-product during drinking water disinfection by chlorine dioxide. Here, we report the effect of dietary antioxidant taurine on NaClO3-induced cytotoxicity in human red blood cells (RBC). RBC were treated with 5 mM NaClO3, either alone or in presence of 1, 2.5 and 5.0 mM taurine. Incubation of RBC with NaClO3 alone caused hemolysis, increased oxidation of lipids and proteins, methemogobin level and decreased total sulfhydryl and glutathione content. It lowered the activities of antioxidant enzymes thioredoxin reductase, glutathione peroxidase, catalase and glutathione reductase, while Cu-Zn superoxide dismutase activity was increased. The antioxidant capacity of RBC was impaired. This strongly suggests that NaClO3 causes the induction of oxidative stress condition in RBC. The specific activities of lactate dehydrogenase, glucose 6-phosphate dehydrogenase and plasma membrane bound enzymes, were also greatly altered. However, prior treatment of RBC with taurine conferred significant protection against NaClO3-induced oxidative damage and also improved the antioxidant defence system of cells. These results were supported by electron microscopy images of RBC. Treatment with NaClO3 alone converted the normal biconcave discoidal RBC to acanthocytes and echinocytes but this transformation was greatly prevented in the presence of taurine. Thus, taurine mitigates the cytotoxicity of NaClO3 in human RBC and can function as an effective chemoprotectant.


Subject(s)
Chlorates , Taurine , Antioxidants/metabolism , Antioxidants/pharmacology , Chlorates/metabolism , Chlorates/pharmacology , Erythrocytes , Glutathione/metabolism , Humans , Lipid Peroxidation , Oxidative Stress , Taurine/metabolism , Taurine/pharmacology
5.
Arab J Urol ; 19(3): 255-263, 2021.
Article in English | MEDLINE | ID: mdl-34552777

ABSTRACT

OBJECTIVE: To review the role of elastography in the evaluation and decision-making of adult, infertile men with varicocele. METHODS: A systematic search using the terms (Elastography) AND (Varicocele), (Stiffness) AND (Varicocele), (Elastography) AND (Male infertility) was performed in Pubmed/Medline. Studies reporting a) elastographic characteristics in varicocele-bearing comparing to normal testicles, and b) the correlation of elastography with varicocele grading, parameters of spermatogenesis, and outcomes of varicocele treatment were selected. Exclusion criteria were animal, adolescents, abstracts, and non-English language studies. RESULTS: In total, 453 articles were identified; 11 eligible studies were selected. Several modalities were used (shear wave elastography, strain elastography, quasistatic ultrasound elastography, acoustic radiation force impulse). Varicocele-bearing testicles have significantly different stiffness and elasticity in comparison to normal and non-varicocele testicles. Although not in full agreement, elastography readings are correlated with semen parameters. Conflicting results were reported regarding grading as most of the studies failed to demonstrate a significant correlation. Shear wave elastography showed a significant correlation with the improvement in semen parameters after varicocelectomy, but the association with pregnancy rates is unknown. Finally, no studies were identified comparing elastography with other modalities. CONCLUSIONS: Elastography can detect changes in the architecture of varicocele-bearing testicles. Although the role of the modality in grading is uncertain, elastography showed a meaningful correlation with spermatogenesis parameters. Importantly, elastography readings could predict the improvement in semen parameters after varicocelectomy which is useful in terms of decision-making in infertile men with varicocele. ABBREVIATIONS: ARFI: acoustic radiation force impulse; CDUS: colour Doppler ultrasonography; DWI: diffusion-weighted imaging; PRISMA: Preferred Reporting Items for Systematic Reviews and Meta-Analyses; SWE: shear wave elastography; VC: varicocele.

6.
Cureus ; 12(5): e8149, 2020 May 16.
Article in English | MEDLINE | ID: mdl-32550068

ABSTRACT

Perioperative arrhythmias can develop due to many reasons, rarely life-threatening, but hypokalemia plays an important role in their development. We report two cases of severe postoperative hypokalemia leading to ventricular fibrillation (VF). Case 1: A young healthy lady developed perioperative severe hypokalemia leading to repeated episodes of VF requiring cardiopulmonary resuscitation (CPR), direct current (DC) shock and anti-arrhythmic therapy, apart from rapid replacement of intravenous potassium. She recovered fully without any neurological or cardiac sequelae. Case 2: A 78-year-old male patient, a known case of hypertension controlled with medications developed postoperative repeated VF due to hypokalemia requiring 210 mmol of potassium chloride, antiarrhythmic therapy, DC shock, and CPR. He recovered, but complicated into acute myocardial infarction requiring therapy. Perioperative severe hypokalemia can lead to life-threatening cardiac arrhythmias. Early recognition and aggressive correction are essential for better outcomes.

7.
Environ Toxicol ; 33(11): 1182-1194, 2018 Nov.
Article in English | MEDLINE | ID: mdl-30144278

ABSTRACT

Sodium chlorate (NaClO3 ) is widely used in paper and pulp industries and as a non-selective herbicide. Humans can be exposed to NaClO3 through contaminated drinking water due to its improper and unchecked usage in industries and as herbicide. NaClO3 is also present as a major stable by-product in drinking water that has been disinfected with chlorine dioxide. In this study, we have investigated the effect of a single acute oral dose of NaClO3 on rat kidney. Adult male Wistar rats were divided into one control and four NaClO3 treated groups that were orally given different doses of NaClO3 and euthanized 24 hr after the treatment. Oral administration of NaClO3 resulted in increased hydrogen peroxide levels, lipid, and protein oxidation while thiol and glutathione content and activities of brush border membrane enzymes were decreased in kidney in a NaClO3 dose-dependent manner. Significant alterations in the activities of enzymes involved in carbohydrate metabolism and antioxidant defense were also observed. Administration of NaClO3 induced DNA fragmentation and increased DNA-protein cross-linking. Histological studies showed marked damage in kidney from NaClO3 treated animals. These results strongly suggest that NaClO3 induces nephrotoxicity via redox imbalance that results in DNA and membrane damage, metabolic alterations and brush border membrane enzyme dysfunction.


Subject(s)
Acute Kidney Injury/chemically induced , Chlorates/toxicity , Herbicides/toxicity , Kidney/drug effects , Microvilli/drug effects , Oxidative Stress/drug effects , Acute Kidney Injury/metabolism , Acute Kidney Injury/pathology , Animals , Antioxidants/metabolism , Carbohydrate Metabolism/drug effects , DNA Damage , Glutathione/metabolism , Kidney/enzymology , Kidney/pathology , Kidney/ultrastructure , Male , Microvilli/enzymology , Microvilli/pathology , Oxidation-Reduction/drug effects , Rats , Rats, Wistar , Toxicity Tests, Acute
8.
J Cell Biochem ; 119(4): 3744-3754, 2018 04.
Article in English | MEDLINE | ID: mdl-29240267

ABSTRACT

Sodium nitrite (NaNO2 ) is widely used as a food additive and preservative in fish and meat products. We have evaluated the effect of a single acute oral dose of NaNO2 on oxidative stress parameters, antioxidant capacity, and DNA in rat kidney. Male Wistar rats were divided into four groups and given single oral dose of NaNO2 at 20, 40, 60, and 75 mg/kg body weight; untreated rats served as the control group. All animals in NaNO2 -treated groups showed marked alterations in various parameters of oxidative stress as compared to the control group. This included increase in lipid peroxidation, protein oxidation, hydrogen peroxide levels, and decrease in reduced glutathione content and antioxidant capacity. Administration of NaNO2 also increased DNA damage as evident from release of free nucleotides and confirmed by comet assay. It also led to greater cross-linking of DNA to proteins. Histological analysis showed marked morphological changes in the kidney of NaNO2 -treated animals. These alterations could be due to increased free radical generation or direct chemical modification by reaction intermediates. Our results suggest that nitrite-induced nephrotoxicity is mediated through redox imbalance and results in DNA damage.


Subject(s)
DNA Damage/drug effects , Kidney/drug effects , Kidney/metabolism , Sodium Nitrite/pharmacology , Animals , DNA Damage/genetics , Glutathione/metabolism , Hydrogen Peroxide/metabolism , Lipid Peroxidation/drug effects , Male , Oxidation-Reduction/drug effects , Rats , Rats, Wistar
9.
Environ Sci Pollut Res Int ; 24(23): 19086-19097, 2017 Aug.
Article in English | MEDLINE | ID: mdl-28660510

ABSTRACT

Nitrite is present as a noxious contaminant in drinking water and causes oxidative damage in various tissues of humans and animals. It is a well-known methemoglobin-forming agent that has been shown to damage blood cells. The protective effect of taurine, a semi-essential sulfur-containing amino acid, was studied on sodium nitrite (NaNO2)-induced oxidative damage in human erythrocytes. Erythrocytes were incubated with NaNO2, in the presence and absence of taurine, and changes in oxidative stress parameters determined. Pretreatment with taurine significantly ameliorated NaNO2-induced oxidative damage to lipids, proteins, and plasma membrane. It also reduced the NaNO2-induced increase in methemoglobin levels and ROS production. Taurine improved the antioxidant capacity of cells, restored the alterations in the activities of various metabolic enzymes, and prevented morphological changes in erythrocytes. Thus, taurine can be potentially used as a protective agent against the damaging effects of nitrite.


Subject(s)
Erythrocytes/drug effects , Methemoglobin/metabolism , Protective Agents/pharmacology , Sodium Nitrite/antagonists & inhibitors , Taurine/pharmacology , Animals , Antioxidants/metabolism , Erythrocytes/metabolism , Humans , Male , Oxidation-Reduction , Oxidative Stress/drug effects , Sodium Nitrite/toxicity
10.
PLoS One ; 12(4): e0175196, 2017.
Article in English | MEDLINE | ID: mdl-28384248

ABSTRACT

Industrialization and unchecked use of nitrate/nitrite salts for various purposes has increased human exposure to high levels of sodium nitrite (NaNO2) which can act as a pro-oxidant and pro-carcinogen. Oral exposure makes the gastrointestinal tract particularly susceptible to nitrite toxicity. In this work, the effect of administration of a single acute oral dose of NaNO2 on rat intestine was studied. Animals were randomly divided into four groups and given single doses of 20, 40, 60 and 75 mg NaNO2/kg body weight. Untreated animals served as the control group. An NaNO2 dose-dependent decline in the activities of brush border membrane enzymes, increase in lipid peroxidation, protein oxidation, hydrogen peroxide levels and decreased thiol content was observed in all treated groups. The activities of various metabolic and antioxidant defense enzymes were also altered. NaNO2 induced a dose-dependent increase in DNA damage and DNA-protein crosslinking. Histopathological studies showed marked morphological damage in intestinal cells. The intestinal damage might be due to nitrite-induced oxidative stress, direct action of nitrite anion or chemical modification by reaction intermediates.


Subject(s)
DNA Damage , Intestines/drug effects , Sodium Nitrite/administration & dosage , Administration, Oral , Animals , Dose-Response Relationship, Drug , Glutathione/metabolism , Hydrogen Peroxide/metabolism , Intestinal Mucosa/metabolism , Intestines/pathology , Lipid Peroxidation , Male , Oxidation-Reduction , Rats , Rats, Wistar , Sulfhydryl Compounds/metabolism
11.
Chemosphere ; 177: 311-316, 2017 Jun.
Article in English | MEDLINE | ID: mdl-28319884

ABSTRACT

Sodium chlorate (NaClO3) is widely used in paper and pulp industries and as a non-selective herbicide. It is also a major by-product generated upon disinfection of drinking water by chlorine dioxide. In this study, we have investigated the genotoxicity of NaClO3 on the small intestine of rats. Adult male rats were divided into 5 groups: one control and four NaClO3 treated groups. The NaClO3 treated groups were given a single acute oral dose of NaClO3 (100, 250, 500 and 750 mg/kg body weight) and sacrificed 24 h later. Administration of NaClO3 caused significant DNA damage in a dose dependent manner in the rat intestine. This was evident from the comet assay which showed DNA strand breaks and was further confirmed by agarose gel electrophoresis and release of free nucleotides. Increased DNA protein cross-linking in NaClO3 administered groups showed formation of a critical lesion which hampers activities of proteins/enzymes involved in DNA repair, transcription and replication. Thus, oral administration of NaClO3 induces DNA damage in the rat intestine, probably through chlorate induced production of reactive oxygen species.


Subject(s)
Chlorates/toxicity , DNA Damage , DNA Repair , Administration, Oral , Animals , Body Weight , Chlorates/administration & dosage , Chlorine Compounds , Comet Assay , Cross-Linking Reagents/chemistry , DNA/chemistry , Disinfection , Dose-Response Relationship, Drug , Drinking Water , Herbicides , Intestine, Small/drug effects , Male , Oxides , Rats , Reactive Oxygen Species/metabolism
12.
J Pak Med Assoc ; 67(2): 166-170, 2017 Feb.
Article in English | MEDLINE | ID: mdl-28138165

ABSTRACT

OBJECTIVE: To determine the aetiology of headache in patients seen for an ocular examination. METHODS: This cross-sectional, descriptive study was conducted at Ophthalmology Department of Karachi Medical and Dental College, Abbasi Shaheed Hospital, Karachi, from January to December 2014, and comprised patients with headache. Patients were registered through non-probability consecutive sampling technique. A predesigned proforma was used to collect data. Complete ocular examination and investigations were conducted along with neuro-ophthalmological examination. Data analysis was done using SPSS 16. RESULTS: Of the 379 patients, 225(59.4%) were female and 154(40.6%) were male. The mean age was 35.12±16.387 years (range: 6-75 years). Conditions associated with headache were divided as ocular, non-ocular and combined pathologies. Among ocular causes, asthenopia was a major entity as 62(16.36%) asthenopic patients presented with refractive errors. These were followed by presbyopics who presented with complaint of headache 56(14.78%). The number of computer users with similar complaint was 18(4.76%). Among other ocular causes of headache, the number of patients with corneal ulcers was 22(5.80%), glaucoma 15(3.96%) and endophthalmitis 4(1.06%). Among the non-ocular causes were hypertension 59(15.57%), sinusitis 41(10.82%) and migraine 47(12.4%). CONCLUSIONS: The majority of patients had associate ocular causes such as refractive errors and anterior segment pathologies.


Subject(s)
Eye Diseases , Headache , Adolescent , Adult , Aged , Ambulatory Care Facilities , Child , Cross-Sectional Studies , Eye Diseases/complications , Eye Diseases/epidemiology , Female , Headache/epidemiology , Headache/etiology , Humans , Male , Middle Aged , Ophthalmology , Pakistan/epidemiology , Tertiary Care Centers , Young Adult
13.
Environ Toxicol ; 32(5): 1607-1616, 2017 May.
Article in English | MEDLINE | ID: mdl-28084674

ABSTRACT

Sodium chlorate (NaClO3 ) is a widely used nonselective herbicide. It is also generated as a by-product during disinfection of drinking water by chlorine dioxide. The purpose of this study was to evaluate the effect of NaClO3 on rat intestine. Adult male rats were randomly divided into five groups: control and remaining four groups were administered orally different doses of NaClO3 and sacrificed 24 h after the treatment. The administration of NaClO3 produced acute oxidative stress in the intestine, which manifested in the form of markedly enhanced malondialdehyde levels and carbonyl content and lowered total sulfhydryl groups and glutathione levels. The activities of several brush border membrane (BBM) enzymes were greatly reduced as compared to control. There were alterations in the activities of various enzymes of carbohydrate metabolism and those involved in maintaining the antioxidant defense system. Histological studies support the biochemical results showing NaClO3 dose-dependent increase in tissue damage. Thus, the present study shows that oral administration of NaClO3 decreases the activities of BBM enzymes, induces oxidative stress, alters metabolic pathways, and impairs the antioxidant system of rat intestine. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 1607-1616, 2017.


Subject(s)
Carbohydrate Metabolism/drug effects , Chlorates/toxicity , Intestines/drug effects , Microvilli/drug effects , Animals , Antioxidants/metabolism , Disinfection , Herbicides/toxicity , Intestinal Mucosa/metabolism , Intestines/enzymology , Kidney/drug effects , Male , Microvilli/enzymology , Oxidation-Reduction/drug effects , Oxidative Stress/drug effects , Rats , Rats, Wistar , Toxicity Tests , Water Pollutants, Chemical/toxicity , Water Purification
14.
Environ Toxicol ; 32(4): 1343-1353, 2017 Apr.
Article in English | MEDLINE | ID: mdl-27478981

ABSTRACT

Sodium chlorite (NaClO2 ) is used in the production of chlorine dioxide for bleaching and stripping of textiles, pulp, and paper. It is also used as disinfectant in municipal water treatment and as a component in therapeutic rinses and gels. The effect of NaClO2 on human erythrocytes has been studied under in vitro conditions. Incubation of 5% suspension of erythrocytes with NaClO2 (0.1-2.0 mM) at 37°C for 30 min resulted in marked cell lysis (1.2-3.8 fold) and increased their osmotic fragility. Several parameters were assayed in cell lysates prepared from NaClO2 -treated and -untreated (control) erythrocytes. Compared to controls, exposure to NaClO2 caused significant increase in protein oxidation (1.1-8.07 fold), lipid peroxidation (1.08-4.95 fold) with decrease in total sulfhydryl (-5 to -61%), and glutathione levels (-7 to -86%). Methemoglobin content was tremendously increased, by 5-52 fold when compared to control, while methemoglobin reductase activity decreased (-17 to -93%) upon NaClO2 treatment. NaClO2 enhanced the generation of reactive oxygen species by 3-21 fold and lowered the metal reducing and free radical quenching ability of erythrocytes. It also caused an increase in nitric oxide levels (2.7-15.4 fold) showing generation of nitrosative stress too. The activities of major antioxidant and membrane bound enzymes were significantly altered. Gross morphological changes, from discocytes to echinocytes, were seen in NaClO2 -treated erythrocytes under electron microscope. These results show that NaClO2 induces oxidative stress in human erythrocytes, damages the membrane, and impairs the cellular antioxidant defence system. This oxidative damage can shorten the life span of erythrocytes in blood resulting in red cell senescence. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 1343-1353, 2017.


Subject(s)
Chlorides/toxicity , Erythrocytes/drug effects , Reactive Oxygen Species/metabolism , Water Pollutants, Chemical/toxicity , Antioxidants/metabolism , Cell Shape/drug effects , Erythrocytes/metabolism , Glutathione/metabolism , Humans , Lipid Peroxidation/drug effects , Methemoglobin/metabolism , Nitric Oxide/metabolism , Oxidative Stress/drug effects
15.
Environ Sci Pollut Res Int ; 24(2): 1898-1909, 2017 Jan.
Article in English | MEDLINE | ID: mdl-27797001

ABSTRACT

Sodium chlorate (NaClO3) is a widely used non-selective herbicide. It is also generated as a byproduct during disinfection of drinking water by chlorine dioxide. In the present work, the effects of NaClO3 on human erythrocytes were studied under in vitro conditions. Incubation of erythrocytes with different concentrations of NaClO3 at 37 °C for 90 min resulted in significant hemolysis. Cell lysates were prepared from NaClO3-treated and untreated (control) erythrocytes and assayed for various biochemical parameters. Methemoglobin levels were significantly increased and methemoglobin reductase activity was reduced upon NaClO3 treatment. There was a significant increase in protein oxidation and lipid peroxidation with a decrease in reduced glutathione and total sulfhydryl content. This suggests the induction of oxidative stress in erythrocytes upon exposure to NaClO3. The occurrence of oxidative stress was confirmed by significantly increased generation of reactive oxygen species and lowered antioxidant response of the cells. NaClO3 treatment also increased nitric oxide levels showing induction of nitrosative stress. The activities of major antioxidant and membrane-bound and metabolic enzymes were significantly altered upon incubation of erythrocytes with NaClO3. The erythrocytes became more osmotically fragile while electron microscopic images showed gross morphological alterations in NaClO3-treated cells. These results show that NaClO3 induces oxidative stress in human erythrocytes, which results in extensive membrane damage and lowers the antioxidant response.


Subject(s)
Chlorates/toxicity , Disinfectants/toxicity , Erythrocytes/drug effects , Herbicides/toxicity , Water Pollutants, Chemical/toxicity , Erythrocytes/metabolism , Glutathione/metabolism , Hemolysis/drug effects , Humans , Lipid Peroxidation/drug effects , Methemoglobin/metabolism , Oxidation-Reduction , Oxidative Stress/drug effects , Reactive Oxygen Species/metabolism
16.
Cell Biol Int ; 40(12): 1320-1331, 2016 Dec.
Article in English | MEDLINE | ID: mdl-27680892

ABSTRACT

Sodium nitrite (NaNO2 ) is a common contaminant of drinking water and food and feed chain. Nitrite induces oxidative damage in humans and animals. In this work, we studied the protective effect of crocin, the active constituent of Crocus sativus (saffron), on NaNO2 -induced oxidative damage in human erythrocytes. Changes in oxidative stress parameters following NaNO2 incubation of erythrocytes in presence and absence of crocin were determined. It was found that crocin pre-treatment significantly attenuated NaNO2 -induced oxidative damage of proteins, lipids, and plasma membrane. Crocin reduced the level of methemoglobin, the primary acute effect of nitrite intoxication. It also improved the antioxidant capacity of cells and NaNO2 -induced morphological changes in erythrocytes. Crocin is thus a potent protective agent against nitrite-induced cytotoxicity.


Subject(s)
Carotenoids/pharmacology , Cytoprotection/drug effects , Erythrocytes/pathology , Methemoglobin/metabolism , Nitrites/toxicity , Oxidative Stress/drug effects , Protective Agents/pharmacology , Adult , Antioxidants/metabolism , Cell Shape/drug effects , Cytochrome-B(5) Reductase/metabolism , Erythrocyte Membrane/drug effects , Erythrocyte Membrane/enzymology , Erythrocytes/drug effects , Erythrocytes/metabolism , Erythrocytes/ultrastructure , Glutathione Disulfide/metabolism , Humans , Models, Biological , Young Adult
17.
J Nutr Sci ; 4: e30, 2015.
Article in English | MEDLINE | ID: mdl-26688721

ABSTRACT

The aim of the present study was to evaluate the oxidation status of North American n-3 (omega-3) PUFA nutritional supplements commercially available in Canada and evaluate the influence of product formulation and delivery form on oxidative safety. A total of 171 North American over-the-counter n-3 PUFA nutritional supplements were analysed for oxidation safety. Primary and secondary oxidation and total oxidation (TOTOX) were determined using the American Oil Chemists' Society (AOCS) procedures. Comparisons between supplements' final forms, oil source and n-3 PUFA concentration quartiles, as measures of product formulations and delivery forms, were compared using ANOVA. Of the products successfully tested, 50 % exceeded the voluntary recommended levels for markers of oxidation. Another 18 % of products were approaching the limits with 1-3 years before expiration. Encapsulated products without flavour additives had significantly lower secondary and TOTOX levels than bulk oils and flavoured products (P < 0·05). Children's products had significantly higher primary, secondary and TOTOX levels compared with all other products (P < 0·05). Markers of oxidation did not differ between oil sources (P > 0·05), with the exception of krill oil products having higher secondary oxidation levels than plant-based products (P > 0·05). Markers of oxidation did not differ between n-3 PUFA supplement concentration quartiles. Consumers may be at risk of exposure to higher levels of oxidative products. New regulatory mandates need to be introduced to ensure that all n-3 PUFA products, used as nutritional supplements, regardless of their formulation or delivery form, can be tested for oxidative safety and compliance.

18.
Toxicol In Vitro ; 29(7): 1878-86, 2015 Oct.
Article in English | MEDLINE | ID: mdl-26231821

ABSTRACT

Nitrite salts are present as contaminants in drinking water and in the food and feed chain. In this work, the effect of sodium nitrite (NaNO2) on human erythrocytes was studied under in vitro conditions. Incubation of erythrocytes with 0.1-10.0 mM NaNO2 at 37 °C for 30 min resulted in dose dependent decrease in the levels of reduced glutathione, total sulfhydryl and amino groups. It was accompanied by increase in hemoglobin oxidation and aggregation, lipid peroxidation, protein oxidation and hydrogen peroxide levels suggesting the induction of oxidative stress. Activities of all major erythrocyte antioxidant defense enzymes were decreased in NaNO2-treated erythrocytes. The activities of enzymes of glycolytic and pentose phosphate pathways were also compromised. However, there was a significant increase in acid phosphatase and also AMP deaminase, a marker of erythrocyte oxidative stress. Thus, the major metabolic pathways of cell were altered. Erythrocyte membrane damage was suggested by lowered activities of membrane bound enzymes and confirmed by electron microscopic images. These results show that NaNO2-induced oxidative stress causes hemoglobin denaturation and aggregation, weakens the cellular antioxidant defense mechanism, damages the cell membrane and also perturbs normal energy metabolism in erythrocytes. This nitrite-induced damage can reduce erythrocyte life span in the blood.


Subject(s)
Erythrocytes/drug effects , Sodium Nitrite/toxicity , Adult , Cells, Cultured , Erythrocyte Membrane/drug effects , Erythrocytes/metabolism , Glutathione/metabolism , Hemoglobins/metabolism , Humans , Lipid Peroxidation/drug effects , Methemoglobin/metabolism , Oxidation-Reduction , Oxidative Stress/drug effects , Young Adult
19.
PLoS One ; 10(3): e0119137, 2015.
Article in English | MEDLINE | ID: mdl-25748174

ABSTRACT

Potassium bromate (KBrO3) is widely used as a food additive and is a major water disinfection by-product. It induces multiple organ toxicity in humans and experimental animals and is a probable human carcinogen. The present study reports the protective effect of dietary antioxidant taurine on KBrO3-induced damage to the rat intestine. Animals were randomly divided into four groups: control, KBrO3 alone, taurine alone and taurine+ KBrO3. Administration of KBrO3 alone led to decrease in the activities of intestinal brush border membrane enzymes while those of antioxidant defence and carbohydrate metabolism were also severely altered. There was increase in DNA damage and DNA-protein cross-linking. Treatment with taurine, prior to administration of KBrO3, resulted in significant attenuation in all these parameters but the administration of taurine alone had no effect. Histological studies supported these biochemical results showing extensive intestinal damage in KBrO3-treated animals and greatly reduced tissue injury in the taurine+ KBrO3 group. These results show that taurine ameliorates bromate induced tissue toxicity and oxidative damage by improving the antioxidant defence, tissue integrity and energy metabolism. Taurine can, therefore, be potentially used as a therapeutic/protective agent against toxicity of KBrO3 and related compounds.


Subject(s)
Bromates/adverse effects , DNA Damage , Disinfectants/adverse effects , Intestinal Mucosa/metabolism , Microvilli/metabolism , Oxidative Stress/drug effects , Taurine/pharmacology , Animals , Bromates/pharmacology , Disinfectants/pharmacology , Humans , Intestines/pathology , Male , Microvilli/pathology , Rats , Rats, Wistar
20.
Mol Cell Biochem ; 396(1-2): 9-22, 2014 Nov.
Article in English | MEDLINE | ID: mdl-25185754

ABSTRACT

Low blood levels of long chain omega-3 polyunsaturated fatty acids (LC n-3 PUFA) have been reported to be associated with increased risk for cardiovascular disease (CVD) deaths. Systematic studies measuring LC n-3 PUFA blood levels (pre and post-treatment) in defined subjects, and monitoring the correction of nutritional deficiency with a pure LC n-3 PUFA formulation in sufficient doses, while monitoring CVD risk factors are lacking. We tested the efficacy of a novel LC n-3 PUFA Medical Food formulation (VASCAZEN(®), > 90 % pure with a 6:1 eicosapentaenoic acid-(EPA):docosahexaenoic acid-(DHA) ratio; 6:1-OM3), to correct such deficiency and determine the concomitant effects on lipid profiles. Of 655 subjects screened, 89 % were LC n-3 PUFA deficient (Omega-Score, (OS) = blood EPA + DHA + Docosapentaenoic acid < 6.1 %). From these, a study was conducted on 110 ambulatory cardiovascular subjects. Placebo: corn oil. Primary endpoint: change in OS. Secondary endpoint: changes in blood lipid profiles. At 8 weeks of treatment with 6:1-OM3 (4 g/day), placebo-adjusted median OS levels (n = 56) significantly improved (132 %, P < 0.0001) with a decrease in AA (arachidonic acid): EPA ratio (82 %, P < 0.0001). In hypertriglyceridemic subjects (TG 2.26-5.65 mmol/L), HDL-C improved (9 %, P = 0.0069), TG-reduced (48 %, P < 0.0001), and VLDL-C reduced (30 %, P = 0.0023), without significantly affecting LDL-C levels. This study confirms that LC n-3 PUFA deficiency is prevalent in the US population, and its correction with 6:1-OM3 in CVD subjects improves lipid profiles. The purity, EPA:DHA ratio and dose are determinant factors for optimal efficacy of a formulation in reducing CVD risk factors.


Subject(s)
Cardiovascular Diseases/diet therapy , Deficiency Diseases/diet therapy , Dietary Supplements , Fatty Acids, Omega-3/blood , Fatty Acids, Omega-3/pharmacology , Adult , Aged , Arachidonic Acid/blood , Cardiovascular Diseases/prevention & control , Docosahexaenoic Acids/blood , Docosahexaenoic Acids/pharmacology , Eicosapentaenoic Acid/blood , Eicosapentaenoic Acid/pharmacology , Fatty Acids, Omega-3/adverse effects , Fatty Acids, Unsaturated/blood , Female , Humans , Male , Middle Aged , Risk Factors , Treatment Outcome , Triglycerides/blood
SELECTION OF CITATIONS
SEARCH DETAIL
...