Biomonitoring of persistent organic pollutants (POPs) in child populations living near contaminated sites in Mexico

The aim of this study was to conduct a POP biomonitoring programme for children in high-risk areas. We evaluated 247 serum samples from children between the ages of 6 and 12years old from two zones in Mexico: (1) indigenous zones, which included Cuatlamayan (CUA), Tocoy (TOC), and Santa Maria Picula (SAM); and (2) industrial zones, which included Tercera Chica (TC), Industrial San Luis (IND) and Rincon de San Jose (SJR); Mundo Nuevo (MN); and Alpuyeca (ALP). Our results showed that α-endosulfan was similar to CUA, TOC, SAM, TC and MN (178.6-306.9ng/g lipid). β-Endosulfan levels were higher in ALP (901.5ng/g lipid), followed by CUA (139.9ng/g lipid) and TOC, SAM, TC and MN, which had similar levels (55.4-64.5ng/g lipid). For endosulfan sulfate, the ALP community had the highest concentration levels (1096.4ng/g lipid), whereas CUA and TOC (212.3 and 289ng/g lipid, respectively) had concentrations similar to those found in SAM and TC (99.5 and 119.1ng/g lipid, respectively). DDE levels were found in malaria-endemic areas of SAM, CUA and TOC (1782.2, 1358.3 and 57.0ng/g lipid), followed by MN (35.1ng/g lipid). HCB concentration levels were found to be higher in MN and SJR (691.8 and 575.4ng/g lipid, respectively), followed by CUA and TC (363.9 and 269.1ng/g lipid, respectively), with levels similar to those found in TOC and SAM (191.8 and 181.9ng/g lipid, respectively). Finally, PCB 101 concentration levels were found to be the highest in ALP (1032.7ng/g lipid), followed by similar levels of SJR and IND (567.5 and 327.3ng/g lipid, respectively) and TC and MN, with 109.1 and 144.5ng/g lipid, respectively. The evidence provided by this exploratory study indicates that the evaluation of the health risks posed to children living in contaminated areas is a high priority health issue.

[Acute voluntary poisoning by carbamate]

Acute poisoning by organophosphate or carbamate is important to recognize since it can cause severe complications such as cardiorespiratory failure, coma, and even death in the absence of early management. Pharmacologically, the mode of action of these substances is based on an inhibition of cholinesterases; the clinical presentation therefore consists of a cholinergic syndrome. The typical clinical picture can be confirmed by the dosage of plasma cholinesterases. On a therapeutic viewpoint, atropine remains the antidote of choice. In high doses, it is the only molecule with a demonstrated effect for the specific treatment of such poisonings. Pralidoxime is clearly recommended in case of poisoning by an organophosphate, but is more discussed when carbamates are involved. The observation of a case of voluntary poisoning by a powerful carbamate, aldicarbe, offers s the opportunity to review the key elements of this type of poisoning. The rather loose inaugural presentation and the initial absence of diagnosis, underline the value of an adequate premature symptomatic care.

Recognition of Lewis x derivatives present on mucins by flagellar components of Pseudomonas aeruginosa

Pseudomonas aeruginosa binds to human respiratory mucins by mechanisms involving flagellar component-receptor interactions. The adhesion of P. aeruginosa strain PAK is mediated by the flagellar cap protein, FliD, without the involvement of flagellin. Two distinct types of FliD proteins have been identified in P. aeruginosa: A type, found in strain PAK, and B type, found in strain PAO1. In the present work, studies performed with the P. aeruginosa B-type strain PAO1 indicate that both the FliD protein and the flagellin of this strain are involved in the binding to respiratory mucins. Using polyacrylamide-based fluorescent glycoconjugates in a flow cytometry assay, it was previously demonstrated that P. aeruginosa recognizes Le(x) (or Lewis x) derivatives found at the periphery of human respiratory mucins. The aim of the present work was therefore to determine whether these carbohydrate epitopes (or glycotopes) are receptors for FliD proteins and flagellin. The results obtained by both flow cytometry and a microplate adhesion assay indicate that the FliD protein of strain PAO1 is involved in the binding of glycoconjugates bearing Le(x) or sialyl-Le(x) determinants, while the binding of flagellin is restricted to the glycoconjugate bearing Le(x) glycotope. In contrast, the type A cap protein of P. aeruginosa strain PAK is not involved in the binding to glycoconjugates bearing Le(x), sialyl-Le(x), or sulfosialyl-Le(x) glycotopes. This study demonstrates a clear association between a specific Pseudomonas adhesin and a specific mucin glycotope and demonstrates that fine specificities exist in mucin recognition by P. aeruginosa.

Adhesion of Pseudomonas aeruginosa to respiratory mucins and expression of mucin-binding proteins are increased by limiting iron during growth

The attachment of Pseudomonas aeruginosa to human respiratory mucus represents an important step in the development of lung infection, especially in cystic fibrosis. Local factors in the respiratory tract, such as osmolarity or iron concentration, might influence this colonization. In the present work, we have observed that overall levels of adhesion of two nonmucoid, nonpiliated strains of P. aeruginosa, 1244-NP and PAK-NP, to human airway mucins were higher when these strains were grown in a minimal medium of low osmolarity (M9) than when they were grown in a rich medium of higher osmolarity (tryptic soy broth [TSB]). However, increasing the NaCl concentration of M9 to increase the osmolarity did not modify the level of binding. In order to find out whether these differences were due to variations in nutrients, the influence of iron concentration was investigated: the levels of binding of the two strains increased after TSB was depleted of iron and decreased after iron was added to M9. Since the outer membranes from the two strains have been shown to contain proteins reacting with human bronchial mucins, we compared the mucin-binding proteins expressed by the two strains grown in different media. When the nonpiliated strains 1244-NP and PAK-NP were grown in the different media, previously observed mucin-binding bands were detected in the 42- to 48-kDa range but additional mucin-binding bands in the 77- to 85-kDa range were detected when these strains were grown in M9 or iron-deprived TSB. These results demonstrate that the adhesion of P. aeruginosa and the expression of mucin-binding proteins in the outer membranes of nonpiliated P. aeruginosa are affected by the iron content of the medium in which the bacteria are grown and not by the osmolarity.

Interactions between glycoconjugates from human respiratory airways and Pseudomonas aeruginosa

Pseudomonas aeruginosa binds to different glycoconjugates in vitro. As six other bacteria, it binds to several glycolipids, mainly asialo GM1 and asialo GM2. Asialo GM1 has been reported to exist at the surface of cystic fibrosis cells. The binding of P. aeruginosa to asialo GM1 involves the pili, especially the C-terminal part of pilin that recognizes the GaINAc(beta 1,4) Gal sequence of asialo GM1.P. aeruginosa may also bind to sialylated membrane-bound glycoproteins. Human salivary and respiratory mucins are also recognized by P. aeruginosa. Mucins represent the main components of mucus. The peptide part (apomucin) of this broad family of secreted glycoproteins is encoded by several mucin genes. The apomucins are covered by a large number of carbohydrate chains that can be remarkably different and represent a mosaic of sites for attachment of microorganisms. The binding of P. aeruginosa to mucins involves outer membrane proteins and mucin carbohydrate chains that are structurally different from the carbohydrate recognized by pillin. Airway and salivary mucins secreted by patients suffering from cystic fibrosis (CF) show alterations in their carbohydrate moiety. The increased sulfation of airway mucins seems to correspond to a primary defect. Other abnormalities such as increased sialylation or fucosylation have also been detected. The binding of P. aeruginosa to airway or salivary mucins is increased in CF. However, the precise link between the carbohydrate alterations and the increased binding of P. aeruginosa to CF mucins remains to be elucidated.

Pseudomonas aeruginosa outer membrane adhesins for human respiratory mucus glycoproteins

The attachment of Pseudomonas aeruginosa to human respiratory mucus represents an important step in the development of lung infection, especially in cases of cystic fibrosis. For this purpose, microtiter plate adhesion assays have been developed and have suggested that nonpilus adhesins of P. aeruginosa are the most important ones for binding to human respiratory mucins. In order to characterize these mucin-binding adhesins, outer membrane proteins (OMP) from two adhesive strains, 1244-NP and PAK-NP, and their poorly adhesive rpoN mutants, 1244-N3 and PAK-N1, were prepared by a mild extraction with Zwittergent 3-14. Mucin-binding adhesins were detected after polyacrylamide gel electrophoresis and blotting of the OMP on nitrocellulose replicas, using human bronchial mucins labeled with 125I. The binding properties of these OMP with lactotransferrin, another glycoprotein abundant in respiratory mucus, were also studied. Radiolabeled mucins detected four bands at 48, 46, 28, and 25 kDa with strain PAK-NP. With the nonmucoid strain 1244-NP, five bands were observed at 48, 46, 42, 28, and 25 kDa. The bands at 48 and 25 kDa were also visualized by radiolabeled lactotransferrin. These bands were partially or completely displaced by nonradiolabeled respiratory mucin glycopeptides but not by tetramethylurea, suggesting that they recognized carbohydrate sites. In contrast, the poorly adhesive strains showed weakly binding bands. These results demonstrate that outer membranes from two different nonpiliated P. aeruginosa strains express multiple adhesins with an affinity for human respiratory mucins and/or lactotransferrin.

Identification of plasma proteins contained in bronchoalveolar fluid from Macacus cynomolgus

1. Serial bronchoalveolar lavages (BAL) were performed on a subhuman primate (Macacus cynomolgus) in order to give an experimental model for silicosis. 2. We have identified and quantified some plasma proteins of monkey BAL fluid. 3. The results were compared to those previously obtained in humans. 4. Two proteins previously detected in human BAL fluid (alpha 1 acid glycoprotein, alpha 1 antichymotrypsin) were not detected in monkey control BAL fluid. 5. Two kinds of transferrins were detected in monkey BAL fluids while only one is described in human. 6. The present results will now permit sequential follow up studies during the course of experimental silicosis.

Isozymes of creatine kinase in mammalian cell cultures

Previous studies on the energy metabolism of rat myocardial cells in culture supported the hypothesis that the creatine-phosphocreatine-creatine kinase system plays an important role in the intracellular transport of energy from the mitochondria to the myofibrils and in the regulation of energy production coupled to energy utilization in this model system. Effective functional compartmentation of ATP could result from the binding of creatine kinase to cellular organelles (e.g., myofibrils and mitochondria) such that high energy charge at the myofibrils is maintained by the reverse creatine kinase reaction, while phosphocreatine is synthesized mainly at the mitochondria in the forward creatine kinase reaction. It was, therefore, essential to demonstrate the presence of mitochondrial creatine kinase in the cultured myocardial cells to support this hypothesis, particularly since the mitochondrial creatine kinase was reportedly absent in fetal hearts. Using electrophoresis on cellulose acetate strips, the mitochondrial creatine kinase isozyme, as well as MM, MB, and BB isozymes, have now been demonstrated in myocardial cultures derived from neonatal rats. The mitochondrial creatine kinase increased with age in culture and with age of animal from which the culture is derived. Furthermore, the addition of creatine to culture media stimulates its synthesis. The mitochondrial creatine kinase isozyme was not detected in nonmuscle cells in culture derived from the neonatal rat hearts, nor in L6 muscle cell line. Phosphocreatine was present in all cells, but the regulation of energy metabolism and energy shuttle by creatine-phosphocreatine-creatine kinase could be operative only in the cells where the mitochondrial creatine kinase is present. This regulatory mechanism provides for an efficient system concomitant with the continuous energy demand of the myocardium; it is not ubiquitous and its development in myocardial cells seems to be triggered postnatally.

[Partial characterization of 2 extracellular aminopeptidases (arylamidases) from the dermatophyte Keratinomyces ajelloi]

Two aminopeptidases AP1 and AP2 have been isolated from Keratinomyces ajelloi filtrates. The molecular weight is about 27 000 for AP1 and 23 000 for AP2. Both aminopeptidases present maximum activity at pH 9.35 but 50 p. 100 of maximum activity is observed between pH 7.5 and pH 8.5. Km values measured at pH 9.35 with L-leucine-p-nitroanilide as substrate are 0.38 X 10(-3) M for AP1 and 0.43 X 10(-3) M for AP2. kcat at the same pH are 63.6 sec.-1 for AP-1 and 62.8 sec-1 for AP2. Both aminopeptidases are inhibited by mercuric chloride, o-phenanthroline, dithiothreitol and 2-mercaptoethanol. Some of their characters make them similar to Streptomyces griseus pronase aminopeptidases.

[Gas-liquid chromatography of non-esterified fatty acids of the rat myocardium]

Non-esterified fatty acids in cardiac cell cultures of postnatal rat, in postnatal rat heart and in ventricle muscle of adult rat were analyzed by gas-liquid chromatography. Among cultured heart cells, three different types were found. Type A0 appeared when arachidonic acid was lacking in tissue culture medium; it had the highest percentage in saturated fatty acids, palmitoleic and linolenic acids. Type A1 and type A2 appeared when arachidonic acid was proved to be present in culture medium. Non esterified fatty acid composition of type A1 was closely similar to that of postnatal rat heart, while type A2 ranged between that of postnatal heart and that of adult ventricular muscle.