Biochemical effects of some pesticides on lipid peroxidation and free-radical scavengers

Oxidative stress was studied in blood samples obtained from lindane, malathion and propoxur poisoning cases admitted to the Guru Teg Bahadur Hospital, Delhi and evaluated for lipid peroxidation, oxygen free radical (OFR) scavenging enzymes, and glutathione (GSH) and related enzymes. Acetylcholine esterase (AChE), gamma glutamyl transpeptidase (GGT) and GSH level were also assayed in lymphocytes. The level of thiobarbituric acid reacting substances and activities of superoxide dismutase, catalase, glutathione peroxidase, glutathione-S-transferase and GGT were increased and GSH level was decreased in pesticide poisoning. Apparently lindane (at the concentration examined) was more potent than malathion and propoxur in producing alteration in lipid peroxidation, GSH related parameters and OFR scavenging enzymes. However, AChE activity and GSH level in lymphocytes of malathion poisoning cases were reduced and GGT activity was enhanced in comparison to control subjects. The present results suggest that OFR scavenging enzymes were induced while combating oxidative stress in a differential manner in organochlorine, organophosphate and carbamate poisoning. Increased lipid peroxidation, coupled with altered levels of GSH and OFR scavenging enzymes in the blood are discussed in the light of oxidative stress.

Pesticide-induced oxidative stress: perspectives and trends

Pesticide-induced oxidative stress as a possible mechanism of toxicity has been a focus of toxicological research for the last decade. Yet for certain pesticides, mechanisms leading to oxidative stress are only partly understood. Pesticide-induced oxidative stress is the final manifestation of a multi-step pathway, resulting in an imbalance between pro-oxidant and antioxidant defense mechanisms. Concomitantly, pesticide intoxication induces a derangement of certain antioxidant mechanisms in different tissues, including alterations in antioxidant enzymes and the glutathione redox system. In this article, we discuss the impact of certain factors that are important in the potentiation of pesticide-induced oxidative stress, immunotoxicity, and apoptosis. Understanding risk factors largely depends upon the cellular and molecular events underlying pesticide-induced stress in experimental animals. These factors must be considered in the safety/toxicity evaluation of any pesticide. The identification and characterization of plant products/drugs might be helpful for understanding the mechanisms of compensation and repair that are due to oxidative stress-induced injury. This paper reviews the nature of such damage, the cellular conditions in which it occurs, and oxidative-stress data that may be applied to the development of risk-assessment methods and models that are designed to reduce some of these uncertainties.

Oxidative stress in term small for gestational age neonates born to undernourished mothers: a case control study

BACKGROUND

The objective of this study was to assess the status of oxidative stress in term small for gestational age (SGA) newborn infants born to undernourished mothers by estimating levels of erythrocyte superoxide dismutase (SOD), catalase, reduced glutathione, and serum malondialdehyde (MDA) in cord blood and comparing them to healthy appropriate for gestational age (AGA) controls. This was done in a case control design at a tertiary level teaching hospital.

METHODS

We included 20 singleton healthy SGA newborn infants born between 38-40 weeks to undernourished mothers with a) post-pregnancy weight < 50 kg or height < 145 cm AND b) hemoglobin < 8.0 g/dL or serum albumin < 2.5 g/dL. An equal number of age and sex matched AGA newborn infants born to healthy mothers served as Controls. Mothers with other risk factors and newborns with complications during delivery or immediate newborn period were excluded. MDA, SOD, catalase and reduced glutathione were measured in the cord blood of all neonates and compared between the groups (unpaired t test); levels were also correlated to maternal weight, height, hemoglobin, and albumin by both univariate (pearsonian correlation) and multivariate (multiple regression) analysis.

RESULTS

The activity of MDA was increased (5.33 +/- 0.72 vs 2.55 +/- 0.22 nmol/mL; P < 0.0001) while levels of superoxide dismutase (493.6 +/- 54.9 vs. 786.8 +/- 79.1 U/g Hb; P < 0.0001), catalase (1.48 +/- 0.24 vs. 2.31 +/- 0.20 U/g Hb; P < 0.0001) and reduced glutathione (2.84 +/- 0.37 vs 6.42 +/- 0.23 Umol/g Hb, P < 0.0001) were decreased in term SGA born to undernourished mothers as compared to term AGA born to healthy mothers. On univariate analysis, all the markers of oxidative stress correlated significantly with maternal parameters (P < 0.005). On multivariate analysis, maternal albumin and hemoglobin accounted for maximum correlation with the markers of oxidative stress.

CONCLUSIONS

Intrauterine malnutrition is associated with significant oxidative stress in small for gestational age neonates born at term to malnourished mothers.

Influence of dietary ginger (Zingiber officinales Rosc) on oxidative stress induced by malathion in rats

Pesticide chemicals may induce oxidative stress leading to generation of free radicals and alterations in antioxidants or oxygen free radical (OFR) scavenging enzymes. Hence, the effect of subchronic malathion (O,O-dimethyl-S-1,2, bis ethoxy carbonyl ethyl phosphorodithioate) exposure was evaluated on lipid peroxidation, glutathione and related enzymes and OFR scavenging enzymes in albino rats. Administration of malathion (20 ppm) for 4 weeks increased the malondialdehyde (MDA) levels in serum, activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) in erythrocytes and glutathione reductase (GR) and glutathione S-transferase (GST) in serum. However, it decreased the glutathione (GSH) level in whole blood. Concomitant dietary feeding of Zingiber officinales Rosc (ginger 1%, w/w) significantly attenuated malathion induced lipid peroxidation and oxidative stress in these rats. These results indicate the possible involvement of free radicals in organophosphate-induced toxicity and highlight the protective action of ginger, an indigenous medicinal plant product.

The role of transient receptor potential vanilloid 1 in mechanical and chemical visceral hyperalgesia following experimental colitis

The transient receptor potential vanilloid 1 receptor (TRPV1) is an important nociceptor involved in neurogenic inflammation. We aimed to examine the role of TRPV1 in experimental colitis and in the development of visceral hypersensitivity to mechanical and chemical stimulation. Male Sprague-Dawley rats received a single dose of trinitrobenzenesulfonic acid (TNBS) in the distal colon. In the preemptive group, rats received the TRPV1 receptor antagonist JYL1421 (10 mumol/kg, i.v.) or vehicle 15 min prior to TNBS followed by daily doses for 7 days. In the post-inflammation group, rats received JYL1421 daily for 7 days starting on day 7 following TNBS. The visceromotor response (VMR) to colorectal distension (CRD), intraluminal capsaicin, capsaicin vehicle (pH 6.7) or acidic saline (pH 5.0) was assessed in all groups and compared with controls and naïve rats. Colon inflammation was evaluated with H&E staining and myeloperoxidase (MPO) activity. TRPV1 immunoreactivity was assessed in the thoraco-lumbar (TL) and lumbo-sacral (LS) dorsal root ganglia (DRG) neurons. In the preemptive vehicle group, TNBS resulted in a significant increase in the VMR to CRD, intraluminal capsaicin and acidic saline compared the JYL1421-treated group (P<0.05). Absence of microscopic colitis and significantly reduced MPO activity was also evident compared with vehicle-treated rats (P<0.05). TRPV1 immunoreactivity in the TL (69.1+/-4.6%) and LS (66.4+/-4.2%) DRG in vehicle-treated rats was increased following TNBS but significantly lower in the preemptive JYL1421-treated group (28.6+/-3.9 and 32.3+/-2.3 respectively, P<0.05). JYL1421 in the post-inflammation group improved microscopic colitis and significantly decreased the VMR to CRD compared with vehicle (P<0.05, >/=30 mm Hg) but had no effect on the VMR to chemical stimulation. TRPV1 immunoreactivity in the TL and LS DRG was no different from vehicle or naïve controls. These results suggest an important role for TRPV1 channel in the development of inflammation and subsequent mechanical and chemical visceral hyperalgesia.

Selected recombinant Aspergillus fumigatus allergens bind specifically to IgE in ABPA

BACKGROUND

Allergic bronchopulmonary aspergillosis (ABPA) is a hypersensitivity lung disease resulting from exposure to Aspergillus fumigatus allergens. Patients with ABPA show elevated Aspergillus-specific serum IgE, a major criterion used in the diagnosis of the disease. Crude culture filtrate and mycelial antigens have been used widely to demonstrate IgE antibody to Aspergillus in the sera of patients. While these antigens have been useful in the diagnosis of ABPA, occasionally they present inconsistency in their reactivity and lack of specificity. Although in recent years, a number of purified A. fumigatus allergens have been produced by molecular cloning, no attempt was made to evaluate them systematically.

OBJECTIVE

To evaluate the recombinant proteins from A. fumigatus for their IgE antibody binding, we studied sera from ABPA patients and controls by antigen specific enzyme linked immunosorbent assay (ELISA).

METHODS

Recombinant Aspergillus allergens Asp f 1, f 2, f 3, f 4, and f 6 were studied for their specific binding to IgE in the sera of ABPA patients, A. fumigatus skin prick test positive asthmatics, and normal controls from the USA and Switzerland. The sera were blinded and studied by ELISA in two different laboratories.

RESULTS

All the recombinant allergens showed IgE antibody binding with sera from patients with ABPA, whereas only fewer asthmatics and normal sera showed significant binding. The three selected recombinant allergens together reacted with all the ABPA patients studied.

CONCLUSIONS

The results demonstrate that Asp f 2, f 4, and f 6 can be used in the serodiagnosis of ABPA, while IgE antibody binding to Asp f 1 and f 3 was not specific.

Respiratory fungal allergy

Fungal allergy including allergic rhinitis, conjunctivitis, bronchial asthma, and allergic bronchopulmonary mycoses results from exposure to spores. In this review we have dealt with the common allergenic fungi and allergens, immunopathogenesis, diagnostic assays, and the possible control of allergy in the future based on epitope-specific immunotherapy and vaccination.

Examination of the function of RANTES, MIP-1alpha, and MIP-1beta following interaction with heparin-like glycosaminoglycans

Chemokines are a group of small proteins that have a variety of functions, including the activation and recruitment of immune cells during episodes of inflammation. In common with many cytokines, it has been observed that chemokines have the potential to bind heparin-like glycosaminoglycan molecules, which are normally expressed on proteoglycan components of the cell surface and extracellular matrix. The significance of this interaction for chemokine activity remains a subject of debate. In this study, Chinese hamster ovary cells were transfected separately with the human chemokine receptors CCR1 and CCR5, and these receptors were shown to induce an intracytoplasmic Ca(2+) flux and cellular chemotaxis following stimulation with the natural CC chemokine ligands (MIP-1alpha, RANTES (regulated on activation normal T cell expressed), and MIP-1beta). In further experiments, mutant CHO cells, with a defect in normal glycosaminoglycan (GAG) expression, were also transfected with, and shown to express similar levels of, CCR1 and CCR5. Although these receptors were functional, it was found that the mutant cells required exposure to higher concentrations of ligands than the wild-type cells in order to produce the same intracytoplasmic Ca(2+) flux. Radioligand binding experiments demonstrated that specific chemokine receptors expressed by wild-type cells had a significantly greater affinity for MIP-1alpha than similar receptors expressed by GAG-deficient mutants. However, there was no significant difference between these cells in their affinity for RANTES or MIP-1beta. In conclusion, it has been demonstrated clearly that GAG expression is not necessary for the biological activity of the chemokines MIP-1alpha, RANTES, or MIP-1beta. However, the presence of cell surface GAGs does enhance the activity of low concentrations of these chemokines by a mechanism that appears to involve sequestration onto the cell surface.

Apoptosis is induced in leishmanial cells by a novel protein kinase inhibitor withaferin A and is facilitated by apoptotic topoisomerase I-DNA complex

Protein kinase C (PKC) is an important constituent of the signaling pathways involved in apoptosis. We report here that like staurosporine, withaferin A is a potent inhibitor of PKC. In Leishmania donovani, the inhibition of PKC by withaferin A causes depolarization of DeltaPsim and generates ROS inside cells. Loss of DeltaPsim leads to the release of cytochrome c into the cytosol and subsequently activates caspase-like proteases and oligonucleosomal DNA cleavage. Moreover, in treated cells, oxidative DNA lesions facilitate the stabilization of topoisomerase I-mediated cleavable complexes, which also contribute to DNA fragmentation. However, withaferin A and staurosporine cannot induce cleavable complex formation in vitro with recombinant topoisomerase I nor with nuclear extracts from control cells. Taken together, our results indicate that inhibition of PKC by withaferin A is a central event for the induction of apoptosis and that the stabilization of topoisomerase I-DNA complex is necessary to amplify apoptotic process.

Comparison of white light and narrow band high definition images in predicting colon polyp histology, using standard colonoscopes without optical magnification

BACKGROUND AND STUDY AIMS

Narrow band imaging (NBI) with optical magnification is useful in predicting colon polyp histology. As magnifying endoscopes are not routinely available, we investigated the use of NBI and high definition white light imaging in determining polyp histology, using images obtained with colonoscopes without optical magnification.

PATIENTS AND METHODS

Images (white light and NBI) of colon polyps less than 10 mm in diameter were collected prospectively from patients undergoing screening colonoscopy and digitally stored. Two endoscopists later reviewed all images and predicted polyp histology as neoplastic or non-neoplastic using a modified Kudo classification. Comparison was made with histopathology.

RESULTS

Separate white light and NBI images of 80 polyps (49 neoplastic, 31 non-neoplastic) from 63 patients were recorded. Mean polyp size was 5.1 +/- 2.1 mm (5.4 +/- 2.2 neoplastic; 4.4 +/- 1.8 non-neoplastic; P = 0.02). In a pooled analysis, NBI correctly predicted neoplastic histology in 93 of 98 images (sensitivity 95 %, positive predictive value [PPV] 94 %) whereas white light did so in 58 of 98 images (sensitivity 59 %, PPV 79 %). NBI correctly predicted non-neoplastic histology in 56 of 62 images (specificity 90 %, negative predictive value [NPV] 92 %) whereas white light did so in 47 of 62 images (specificity 76 %, NPV 54 %).

CONCLUSIONS

NBI without optical magnification was more accurate in predicting colon polyp histology compared with white light imaging. Image quality and confidence in histology were significantly higher in the NBI group. NBI without optical magnification may be useful in predicting colon polyp histology.

Immunological characterization of Asp f 2, a major allergen from Aspergillus fumigatus associated with allergic bronchopulmonary aspergillosis

The 37-kDa recombinant protein Asp f 2, encoding an allergen of Aspergillus fumigatus, was expressed in a prokaryotic expression system and immunologically evaluated for its functional and structural properties. The open reading frame for a 310-amino-acid-long protein was shown to encode a signal peptide of 31 amino acids. A native 37-kDa culture filtrate protein and a 55-kDa mycelial glycoprotein (gp55) exhibited complete N-terminal sequence homology to Asp f 2. A GenBank search for homologous proteins revealed 60 and 44% sequence homologies to the cytosolic protein ASPND1 from Aspergillus nidulans and fibrinogen binding protein from Candida albicans, respectively. The glycosylation sites and cysteine molecules are conserved in all the three proteins. The extracellular matrix protein laminin showed a dose-dependent interaction with Asp f 2. This protein, expressed as a major cell-associated protein within 24 h of in vitro fungal culture, comprises 20 to 40% of total fungal protein. Furthermore, both native and recombinant Asp f 2 exhibited specific immunoglobulin (IgE) binding with allergic bronchopulmonary aspergillosis (ABPA) and cystic fibrosis-ABPA patients, whereas A. fumigatus-sensitized allergic asthma and normal control subjects failed to show IgE binding with Asp f 2. These results indicate that Asp f 2 is a major allergen of A. fumigatus exhibiting IgE antibody binding with sera from patients with ABPA. The antigen should be explored further for its potential role in the differential diagnosis of A. fumigatus-associated allergic diseases.

Posttransplant bronchiolitis obliterans syndrome is associated with bronchial epithelial to mesenchymal transition

Bronchiolitis obliterans syndrome (BOS) compromises lung transplant outcomes and is characterised by airway epithelial damage and fibrosis. The process whereby the normal epithelial configuration is replaced by fibroblastic scar tissue is poorly understood, but recent studies have implicated epithelial mesenchymal transition (EMT). The primary aim of this study was to assess the utility of flow cytometry in detecting and quantifying EMT in bronchial epithelial cells. Large airway brushings were obtained at 33 bronchoscopies in 16 BOS-free and 6 BOS grade 1-3 patients at 2-120 months posttransplant. Flow cytometry was used to assess expression of the mesenchymal markers alphaSMA, S100A4 and ED-A FN and HLA-DR. TGF beta 1 and HGF were measured in Bronchoalveolar lavage (BAL). Expression of all three mesenchymal markers was increased in BOS, as was HLA-DR. BAL HGF, but not TGF beta 1 was increased in BOS. Longitudinal investigation of one patient revealed a 100% increase in EMT markers concurrent with a 6-fold increase in BAL TGF beta 1 and the diagnosis of BOS at 17 months posttransplant. Flow cytometric evaluation of bronchial epithelium may provide a novel and rapid means to assess lung allografts at risk of BOS.

Organochlorine pesticide residue levels and oxidative stress in preterm delivery cases

A number of studies have focused attention on various biochemical abnormalities evoked due to exposure to organochlorine pesticides (OCPs). The aim of the present study was to analyze the OCP residues in maternal and cord blood of women and assess the levels of different non-enzymatic oxidative stress markers as well as to establish correlation with OCP levels, if any. Thirty women in each group of full-term delivery (FTD; ≥37 weeks of gestation) and preterm delivery (PTD; <37 weeks of gestation) were enrolled in this study. Levels of OCPs like Hexachlorocyclohexane (HCH), endosulfan, p,p′ Dichlorodiphenyldichloroethylene (DDE) and p,p’ Dichlorodiphenyltrichloroethane (DDT) were analyzed by gas chromatography. Non-enzymatic oxidative stress was measured by the quantification of malondialhyde (MDA), protein carbonyl, reduced glutathione (GSH) and ferric-reducing ability of plasma (FRAP). MDA and protein carbonyl levels were increased significantly, while the levels of GSH and FRAP were decreased in PTD in comparison to FTD cases. We have observed higher levels of β-HCH and α-endosulfan and increased oxidative stress in PTD than FTD cases. In PTD cases, a significant positive correlation was observed between maternal blood levels of β-HCH and MDA (r = .78), β-HCH and GSH (r = —.65), γ-HCH and MDA (r = .89), γ-HCH and GSH (r = —.74) and α-endosulfan and MDA (r = .54) in PTD cases. We also found significant correlations between cord blood levels of β-HCH and MDA (r = .59), β-HCH and GSH (r = —.69), γ-HCH and MDA (r = .62) and α-endosulfan and MDA (r = .54) in PTD cases. In conclusion, our results suggest that higher levels of some of the OCP residues may be associated with PTD and increased oxidative stress.

Sonographic detection of foreign bodies of the extremities

A prospective study to assess the accuracy of ultrasound in the detection and localization of foreign bodies of the extremities was undertaken. Forty-five patients with clinical suspicion of foreign bodies were included in the study. Among 20 patients with radio-opaque foreign bodies, ultrasonic detection of foreign bodies was achieved in 19 patients. In 25 patients, with no radiographic evidence of foreign body, ultrasonic detection of foreign bodies was made in seven patients and among these foreign bodies were confirmed and removed at surgery in five patients. Accurate pre-operative ultrasonic localization of foreign bodies was carried out in three patients.

Relationship of possible stress-related biochemical markers to oxidative/antioxidative status in obsessive-compulsive disorder

Free radicals have been found to play an important role in obsessive-compulsive disorder (OCD). So, we measured the oxidative/antioxidative status of OCD patients, and assessed its use as a biological marker. The study was carried out on 20 healthy and 20 OCD subjects, aged between 20 and 40 years. Biochemical parameters of all subjects were assessed and compared. A significant difference in superoxide dismutase (SOD) levels was observed between the OCD and control groups (p < 0.05); malondialdehyde (MDA) levels were also significantly higher in OCD subjects (p < 0.05). Our study found an overall oxidative imbalance in OCD, leaning towards the antioxidant side in sufferers (specifically towards SOD). SOD has a protective role in overcoming oxidative stress; therefore, oxidative stress could have a pathophysiological role in OCD. Therapy specifically targeting MDA production will have a beneficial effect in overcoming the oxidative stress, anxiety and affective disorder which may be associated with OCD.

The influence of various factors on immune toxicity assessment of pesticide chemicals

Various physiological and environmental factors are known to modulate pesticide-induced immune toxicity. Some of these factors studied in our laboratory are: (a) level of exposure (amount, duration and frequency), (b) human cases/animal models, (c) antigen, its route and adjuvant used, (d) immunological method used, (e) nutritional status and pathological conditions, (f) biotransformation and activity of metabolites, (g) physical/emotional stress, and (h) oxidative stress. These factors complicate the assessment of immune toxicity of pesticide, generally affecting the dose at which toxic effects are observed. Working with organochlorine, organophosphate and carbamate compound, we have found that: (1) dietary protein deficiency makes the immune system more susceptible to the toxic effects of pesticides; (2) suppression of immune responses by the immediate metabolites is an important determinant of the toxicity of parent compound; (3) the type and duration of physical or emotional stress and possible involvement of free radicals (oxidative stress) are important in the potentiation of pesticide-induced immune toxicity. An understanding of these risk factors depends largely upon the cellular and molecular events underlying pesticide-induced immune alterations in experimental animals. These factors, therefore, must be considered in the safety/toxicity evaluation of any pesticide. This paper reviews the influence of these factors on the immune-toxicity of some common pesticides.

Molecular cloning and expression of a recombinant Aspergillus fumigatus protein Asp f II with significant immunoglobulin E reactivity in allergic bronchopulmonary aspergillosis

The cDNA of Aspergillus fumigatus encoding an allergen was cloned and expressed in Escherichia coli. The 987 bp long cDNA clone expressed a recombinant protein Asp f II of 34 kd. This protein exhibited binding to immunoglobulin E (IgE) in the serum samples from patients with allergic bronchopulmonary aspergillosis (ABPA). The patients with ABPA and central bronchiectasis demonstrated high levels of serum IgE antibodies, whereas patients with ABPA without central bronchiectasis, patients with asthma and Aspergillus skin test reactivity but no evidence of ABPA, and patients with aspergilloma showed only low levels of IgE antibody to Asp f II. In two-dimensional electrophoresis, a native antigen electroeluted from an A. fumigatus culture filtrate antigen preparation showed an isoelectric point and molecular weight similar to that of Asp f II. In a competitive enzyme-linked immunosorbent assay (ELISA), the IgE antibody reactivity of Asp f II with patient serum samples could be significantly inhibited by culture filtrate antigens of A. fumigatus. These results indicate that Asp f II has immunologic reactivities comparable to those of native A. fumigatus antigens. The recombinant Asp f II can be expressed in E. coli in large quantities and should prove useful as a standardized allergen for sensitive and specific immunodiagnosis of ABPA, especially in patients with central bronchiectasis.

Effect of reflux-induced inflammation on transient receptor potential vanilloid one (TRPV1) expression in primary sensory neurons innervating the oesophagus of rats

A possible mechanism of oesophageal hypersensitivity is the acid-induced activation of transient receptor potential vanilloid receptor 1 (TRPV1) in the primary sensory neurons. We investigated TRPV1 expression and its colocalization with substance P (SP) and isolectin B4 (IB4)-positive cells in the thoracic dorsal root ganglia (DRGs) and nodose ganglia (NGs) of rats with reflux-induced oesophagitis (RO). RO was developed by fundus ligation and partial obstruction of the pylorus of Sprague-Dawley rats. Four groups of rats were used; fundus ligated acute (RO 48 h), chronic 7 days (RO 7D), RO 7D + omeprazole (7D + Omz, 40 mg kg(-1), i.p.) and sham-operated controls. Immunohistochemical analysis of TRPV1, SP and IB4 expression were carried out in spinal cord (SC), DRGs and NGs. RO rats exhibited significant inflammation and increase in TRPV1-ir and SP-ir expressions in the SC, DRGs and NGs. The maximum colocalization of TRPV1 and SP was observed in RO 7D rats, but Omz prevented inflammation and over expression of TRPV1 and SP. TRPV1-ir significantly increased in IB4-positive cells in DRGs and SC, but not in the NGs. Results document that acid-induced oesophagitis increases TRPV1 expression in both SP- and IB4-positive sensory neurons. The over expression of TRPV1 may contribute to oesophageal hypersensitivity observed in gastro-oesophageal reflux disease (GORD).

Organochlorine pesticide levels and risk of Alzheimer’s disease in north Indian population

Alzheimer’s disease (AD) could result from a multifactorial process involving both genetic predisposition and exposure to environmental factors like pesticides. A case control study of 70 patients of AD and 75 controls was done to examine the association between organochlorine pesticides (OCPs) and risk of AD. OCPs (hexachlorocyclohexane (HCH), aldrin, dieldrin, endosulfan, pp′-dichlorodiphenyldichloroethylene ( pp′-DDE), op′-DDE, pp′-dichlorodiphenyltrichloroethane ( pp′-DDT), op′-DDT, pp′-dichlorodiphenyldichloroethane ( pp′ -DDD) and op′-DDD) were extracted from blood and quantitatively estimated using gas chromatography. A Mann–Whitney U test revealed significant difference in β-HCH levels ( U = 1237.00, W = 4087.00, z = −6.296, p = 0.000, r = −0.71), dieldrin levels ( U = 1449.00, W = 4299.00, z = −5.809, p = 0.000, r = −0.68) and pp′-DDE levels ( U = 2062.00, W = 4912.00, z = −2.698, p = 0.007, r = −0.59) between AD patients and controls. In conclusion, this study supports epidemiological studies that associate exposure to pesticides with increased risk of AD, and we identified the specific pesticides β-HCH, dieldrin and pp′-DDE that are associated with the risk of AD in the north Indian population. However, further research is needed to establish the potential role of these OCPs as an etiologic agent for AD case.

Purification of a major allergen, Asp f 2 binding to IgE in allergic bronchopulmonary aspergillosis, from culture filtrate of Aspergillus fumigatus

BACKGROUND

Most cases of allergic bronchopulmonary aspergillosis (ABPA) are caused by the fungus Aspergillus fumigatus. Successful treatment of this disease depends on early diagnosis with the use of well-characterized and relevant antigens/allergens of the organism.

OBJECTIVE

The aim of this study was to purify and characterize relevant proteins from A. fumigatus that could be used in the reliable diagnosis of ABPA.

METHODS

Monoclonal antibodies were raised against A. fumigatus culture filtrate antigens. A Concanavalin A nonbinding protein fraction was purified with use of one of the monoclonal antibody immunoaffinity columns. The purified protein was analyzed on sodium dodecylsulfate-polyacrylamide gel electrophoresis gel and Western blots. The sensitivity and specificity of the purified protein were evaluated by RAST and ELISA with sera from 25 patients with ABPA, from 10 with allergic asthma, and from 10 normal control subjects.

RESULTS

The 37 kD Concanavalin A nonbinding protein reacted specifically with IgE antibodies in patients with ABPA. Among the 25 patients with ABPA studied, 96% had IgE antibody against the allergen, whereas none of the subjects with allergic asthma who had positive results on the skin prick test or normal control subjects had a reaction. Both RAST and ELISA results exhibited strong correlation with IgE binding. This allergen exhibited N-terminal sequence identity to a recombinant allergen Asp f 2.

CONCLUSIONS

A 37 kD protein with complete N-terminal homology to Asp f 2 is a major allergen of A. fumigatus that significantly reacts with IgE antibody in patients with ABPA, but does not elicit reaction in Aspergillus-sensitive subjects with asthma and normal control subjects.

Fungal allergens and peptide epitopes

Fungal allergens represent a major cause of atopic disorders. Immunochemical and molecular characterization of fungal allergens has been hampered by the lack of pure proteins and to inherent variation among fungal proteins and in their poor yields. With the advent of molecular biology techniques, a number of allergens have been cloned, sequenced, and expressed from a variety of fungal species. The knowledge of the primary, secondary, and tertiary structures of these allergens, the immunodominant regions of these proteins, and their interaction with T and B-cell epitopes, results in better understanding of the molecular mechanisms of allergy and may provide avenues of immunologic intervention to treat patients. The present review deals with the current understanding of fungal allergen epitopes.

Organochlorine pesticide levels in maternal blood and placental tissue with reference to preterm birth: a recent trend in North Indian population

Organochlorine pesticides (OCPs) have been widely used in public health and agriculture programs in developed as well as developing countries, including India. Being xenoestrogenic in nature, OCPs may act as endocrine disruptors leading to preterm birth (PTB) through disturbance of normal estrogen-progesterone ratio. PTB is the leading cause of neonatal deaths worldwide. Therefore, the present study is aimed to determine the extent to which persistent environmental chemicals may accumulate in pregnant women and placenta and ascertain possible associations between exposure level and period of gestation (POG), baby weight, and/or placental weight in PTB cases. Maternal blood and placenta samples of PTB cases (n = 50) and subjects of term delivery as controls (n = 50) were collected. OCP residue levels were estimated by the gas chromatography system equipped with an electron capture detector. Significantly higher levels of α-hexachlorocyclohexane (α-HCH), β-hexachlorocyclohexane (β-HCH), dichlorodiphenyldichloroethane (DDD), and dichlorodiphenyldichloroethylene (DDE) were found in maternal blood of PTB cases as compared to control. Significantly higher levels of DDE and dichlorodiphenyltrichloroethane (DDT) were also found in placental tissue of PTB cases as compared to control group. There was a statistically significant negative correlation between maternal blood level of α-HCH and birth-weight (r = -0.299) and POG (r = -0.234). γ-Hexachlorocyclohexane (γ-HCH) and dieldrin had a negative correlation with placental weight (r = -0.401 and -0.256, respectively), and DDE and β-HCH had a negative correlation with POG (r = -0.251 and -0.229, respectively). The presence of OCPs in maternal blood and placental tissue represents prenatal exposure hazard for fetuses due to chronic bioaccumulation and poor elimination with possible deleterious effect on health.

Conformational and linear B-cell epitopes of Asp f 2, a major allergen of Aspergillus fumigatus, bind differently to immunoglobulin E antibody in the sera of allergic bronchopulmonary aspergillosis patients

Asp f 2 is a major Aspergillus fumigatus allergen involved in allergic bronchopulmonary aspergillosis. Knowledge of the B-cell epitopes may contribute to the understanding of immunoregulation and immunodiagnosis. To elucidate the immunoglobulin E (IgE) binding epitopes in the linear sequence of Asp f 2, we synthesized decamer peptides spanning the whole molecule of Asp f 2 on derivatized cellulose membranes and evaluated IgE binding in ABPA patient and control sera. Peptides three to five amino acids long were synthesized based on amino acid sequences within the IgE binding regions and evaluated for the specificity of epitope antibody interactions. Nine IgE binding regions were recognized in this protein of 268 amino acid residues. Of the nine epitopes, seven (ATQRRQI, RKYFG, HWR, YTTRR, DHFAD, ALEAYA, and THEGGQ) are present in the hydrophilic regions of Asp f 2. Immunologic evaluation of the three recombinant fragments, Asp f 2A encompassing the N-terminal epitope region, Asp f 2B without N- and C-terminal regions of the protein, and Asp f 2C representing C-terminal epitopes, revealed that either the N- or C-terminal region of the protein is essential for the correct folding and conformation for IgE antibody binding.

A case control study of gene environmental interaction in fetal growth restriction with special reference to organochlorine pesticides

OBJECTIVES

Organochlorine pesticides (OCPs) and oxidative stress are reported to be associated with adverse reproductive outcomes. Glutathione S-transferase (GST) is a polymorphic supergene family involved in the detoxification of numerous toxins including OCPs. OCPs are endocrine disrupter and prenatal exposure to them may be associated with fetal growth restriction (FGR). The objectives of the present study were (i) to determine the frequencies of polymorphic alleles of GSTM1 and GSTT1 genes in women with idiopathic FGR, (ii) to analyze the maternal and cord blood levels of the OCPs, and (iii) to identify the gene environment interaction that increases the risk of FGR.

STUDY DESIGN

Maternal and cord blood samples of 50 FGR cases (birth weight <10 percentile for gestational age as per Lubchenco's growth chart) and equal number of normal pregnancies who were occupationally non exposed to OCPs and excluding all the known high risk factors such as anemia, hypertension, antiphospholipid antibody syndrome, medical disease, dietary habit, living style, parity, and BMI. The collected samples at the time of delivery/after delivery were analyzed for OCPs levels by gas chromatography and polymorphic analysis for GSTM1/GSTT1 gene using multiplex PCR.

RESULTS

Significantly higher levels of α,β,γ-HCH and p,p'-DDT were found in maternal blood and significantly higher levels of β and γ-HCH and p,p'-DDT were found in cord blood of FGR cases as compared to controls. The genotypic distribution of GSTM1/GSTT1 was almost similar in both the groups, but the frequency of GSTM1-/GSTT1- (null) genotype was significantly higher in FGR cases as compared to controls (p<0.05, OR=6.42). When interaction between GSTM1/GSTT1 genes polymorphism-OCPs levels and birth weight (gene-environment interaction) was ascertained, a significant association was seen between β-HCH and GSTM1- genotype with reduction in birth weight of 213g.

CONCLUSION

Higher levels of OCPs in pregnant women may be considered as an important aetiological factor in 'idiopathic' FGR. GST polymorphism can influence the relationship between prenatal exposure to pesticides and FGR. The present study provides evidence that polymorphism in xenobiotic metabolising genes may modify the effect of environmental health hazards and increase the risk of FGR.