Determination of biological reference values for chlorpyrifos metabolites in human urine using a toxicokinetic approach

Urinary biomarkers of chlorpyrifos (CPF) exposure are often measured in field studies, although biological reference values (BRVs) are not yet available to assess health risks. This study aimed at proposing BRVs for CPF metabolites in workers' urine based on a toxicokinetic approach. As a first step, a toxicokinetic model was developed, using published human kinetic data, to link the absorbed dose of CPF under a variety of exposure routes and temporal scenarios to the urinary excretion of its major metabolites, 3,5,6-trichloro-2-pyridinol (3,5,6-TCP) and alkyl phosphates (AP). The model was then used to propose BRVs for CPF metabolites in urine below which workers should not experience adverse health effects. This was achieved by linking (1) a literature-reported, repeated CPF no-observed-effect level (NOEL) daily exposure dose for the inhibition of red-blood-cell acetylcholinesterase activity to a corresponding absorbed daily dose, and (2) this absorbed daily dose to the urinary excretion of CPF metabolites. Model simulations under a variety of exposure scenarios showed that the safest BRVs are obtained from a dermal exposure scenario with the slowest absorption rate compatible with available literature data rather than from respiratory or oral exposure scenarios. Also, model simulations showed that, for a given total absorbed dose, absorption over 8 hours results in smaller 3,5,6-TCP and AP urinary excretion rates than those obtained from the same dose absorbed over shorter durations. From these considerations, BRVs were derived by simulating an 8-hour dermal CPF exposure such that the total absorbed daily dose corresponds to the absorbed NOEL. The reference values are proposed in the form of total amounts of 3,5,6-TCP and AP metabolites excreted in urine over chosen time periods (24 and 48 hours).     

Amniotic membrane transplantation and fibrin glue in the management of corneal ulcers and perforations: a review of 33 cases

PURPOSE: To evaluate the efficacy of amniotic membrane in corneal ulcers refractive to conventional treatment and amniotic membrane with fibrin glue in corneal perforations. METHODS: Amniotic membrane transplantation (AMT) was performed in 33 eyes from 32 patients for corneal ulcers refractive to conventional treatment. Fourteen ulcers were perforated and received fibrin glue and amniotic membrane. Ulcers were divided into 3 groups: neurotrophic or exposure, autoimmune, and other etiology. RESULTS: Overall success was observed in 80% (27/33 eyes) of the cases, with success rates of 87.5% (14/16 eyes), 70% (7/10 eyes), 85.7% (6/7 eyes) in groups 1, 2, and 3, respectively. The ulcers healed in a mean time of 3.6 +/- 1.6 weeks and the follow-up was 14.8 +/- 9.9 months. Failure was noted in 6 eyes with severe neurotrophic keratitis, Stevens-Johnson syndrome, ocular cicatricial pemphigoid, and Acanthamoeba keratitis. Grafts with fibrin sealant showed a success rate of 92.9 % (13/14 eyes) compared to 73.7% (14/19 eyes) for amniotic grafts alone. In patients with severe limbal damage, a success rate of only 20% (1/5) was observed. CONCLUSIONS: AMT is a viable option in the treatment of nonhealing corneal ulcers of various depth and etiologies. Perforations up to 3 mm can be safely managed by fibrin glue and AMT. These techniques lead to rapid reconstruction of the corneal surface and can give a good final functional result or allow keratoplasty to be done in more favorable conditions.     

Molecular characterisation and mechanisms of resistance of multidrug-resistant human Salmonella enterica serovar Typhimurium isolated in Amiens (France)

Antimicrobial resistance patterns of Salmonella enterica serovar Typhimurium isolates obtained during the study period were examined. The molecular epidemiology and the mechanisms of resistance to ampicillin, chloramphenicol and tetracycline were investigated. Resistance to ampicillin increased from 59% between 1996 and 1999 to 62.5% in 2000 and to 66.6% in 2001. Of 51 S. Typhimurium isolates studied, 100% were resistant to ampicillin (minimum inhibitory concentration (MIC)>256 mg/L) and sulphonamide (MIC range, 128 to >256 mg/L). Ninety-eight percent of isolates were resistant to streptomycin (MIC range, 48-256 mg/L), 92.2% to tetracycline (MIC range, 32 to >256 mg/L), 88.2% to chloramphenicol (MIC>256 mg/L), 21.5% to sulphamethoxazole/trimethoprim (MIC>32 mg/L), 5.8% to amoxicillin/clavulanic acid (MIC, 32 mg/L) and 1.9% to cefalothin (MIC, 64mg/L). Six resistance phenotypes were found (a-f), with phenotypes a (47%) and b (27.5%) being predominant. Twenty-five (49%) of 51 isolates produced a single beta-lactamase, among which 48% produced PSE-1, 44% produced TEM-1 and 8% produced OXA-1. Among 26 of the 51 isolates, 10 produced PSE-1+OXA-1, 7 produced TEM-1+PSE-1+OXA-1, 6 produced TEM-1+PSE-1, and 3 produced TEM-1+OXA-1. Forty-eight (94.1%) of the 51 isolates had the plasmid-mediated resistance gene flo(ST) to chloramphenicol and tetracycline. Combining enterobacterial repetitive intergenic consensus polymerase chain reaction (ERIC-PCR) and pulsed-field gel electrophoresis (PFGE), 16 distinct patterns were identified, among which patterns IA (35.3%) and IF (27.4%) were considered as epidemic patterns. The dendrogram obtained from S. Typhimurium pulsotypes allowed five clones (S1-S5) to be identified, with two prevalent clones comprising 47.8% (S2) and 27.3% (S4) of the isolates.     

Reproductive abnormalities in human insulin-like growth factor-binding protein-1 transgenic male mice

Adult transgenic mice overexpressing human insulin-like growth factor-binding protein-1 in the liver present reproductive abnormalities in both sexes. In the present work, we have investigated the mechanisms responsible for limiting breeding capacity in these transgenic male mice. Homozygous adult transgenic male mice (3-6 months old) exhibited irregular copulatory behavior and a reduction of the number of pregnancies per female as well as of litter size per pregnancy. Genital tract weight, more specifically epididymal and seminal vesicle weights, were reduced by 45% in homozygous transgenic vs. nontransgenic mice. Homozygous transgenic mice exhibited a 30% reduction of the length of seminiferous tubules (P = 0.007), a 30% decrease in daily sperm production per testis (P = 0.019), and a 50% decrease in the number of spermatozoa in testis (P = 0.037), associated with morphological abnormalities of the sperm heads leading to an approximately 50% reduction of fertilized two-cell eggs (P = 0.002) and of implanted embryos on d 5.5 after mating (P = 0.004). The round spermatids also appeared altered in their morphology. In addition, Leydig cells in homozygous transgenic mice exhibited an altered appearance, with a 1.8-fold increase in lipid droplets in their cytoplasm (P < 0.001). Moreover, the concentration of 3beta-hydroxysteroid dehydrogenase was 66% lower in testis from transgenics compared with those from normal mice (P = 0.01), leading to a tendency toward lower plasma testosterone levels (P = 0.1). Interestingly, LH concentrations were increased by 40% in transgenic pituitary extracts (P = 0.02), and basal LH secretion by pituitary explants in vitro was increased by 60% in homozygous transgenic vs. normal mice (P = 0.04), suggesting an alteration of LH pulsatile secretion in vivo. In conclusion, these data suggest that the breeding impairment of human insulin-like growth factor-binding protein-1 transgenic males is due at least in part to an alteration of the process of spermatogenesis, leading to a diminution of sperm production and of its quality. Minor impairment of steroidogenesis may also contribute to the reduced reproductive capacity of these animals. Our observations are consistent with the idea that normal spermatogenesis and perhaps also steroidogenesis are dependent on the actions of sufficient concentrations of unbound IGF-I.     

Systemic amyloidosis complicating multidrug-resistant tuberculosis in childhood

Multidrug-resistant tuberculosis is increasingly common and is associated with long diagnostic delay and high morbidity. We present a 7-year-old child who developed steroid-resistant nephrotic syndrome while receiving treatment for tuberculosis. Renal biopsy results showed systemic amyloidosis; culture of peritoneal tissue confirmed disseminated multidrug-resistant tuberculosis.     

Tanning behaviors and determinants of solarium use among indoor office workers in Queensland, Australia

Using cross-sectional survey data from Brisbane, Australia, this study identifies prevalence and factors associated with indoor tanning in office workers. Over 12-months, 72/2867 (2.5%) survey participants used solaria. Twenty-eight sunbed users (39%) tanned outdoors and used spray-tans and 42 (58%) reported burns after indoor tanning. Results from regression modelling suggests the strongest predictors of sunbed use were beliefs that tanning was safer indoors than outdoors (OR 6.1, 95%CI: 2.6-14.0) and engaging in outdoor tanning (OR 4.1, 95%CI: 1.8-9.0). We recommend that health authorities promote health gains by reducing ultraviolet radiation exposure or substituting indoor tanning with a spray-on tan.     

Apolipoprotein(a) isoforms immunoblotting detection: comparative study of two methods

This study reports the comparison between two methods (chemiluminescence and enzymatic colorimetry) for revelation of apolipoprotein(a) [apo(a)] isoforms by immunoblotting in 102 Ivorian healthy subjects. Apo(a) isoform sizes were determined by sodium dodecyl sulfate-agarose-polyacrylamide gel electrophoresis (SDS-PAGE) followed by immunoblotting using enzymatic colorimetry or chemiluminescence. Within-run precision was comprised between 4.9% and 9.2% for colorimetry and between 2.9% and 4.6% for chemiluminescence. Both methods have detected apo(a) isoforms in all patients, even when lipoprotein(a) concentrations were under detection limit (0.02?g/L). The two methods were significantly correlated (r?=?0.96 to 0.98, p<0.0001). Even though the chemiluminescence method exhibited better performances than the colorimetric method, both techniques could be used indifferently.     

Viral elution and concentration method for detection of influenza A viruses in mud by real-time RT-PCR

The role of environmental reservoirs in avian influenza virus (AIV) transmission has been investigated during AIV-associated outbreaks. To date, no method has been defined for detection of AIV from mud samples. A procedure using elution and polyethylene glycol (PEG) concentration steps was designed to detect AIV by RT-PCR from 42 g of raw mud, corresponding to 30 g of the solid fraction of mud. RNA was recovered with MagMAX AI/ND Viral RNA Isolation kit (Ambion, Austin, TX). Three elution buffers were studied and viral recoveries higher than 29% were yielded by elution with a 10% beef extract solution (pH 7). The overall method showed that, under some conditions, virus was not detectable in PEG samples, whereas viruses were detected in the elution fractions. PCR curves were improved significantly by running the amplification reaction with a mixture containing a PCR additive for inhibitor removal, such as T4 gene 32 protein (Gp32), although PCR inhibitors from mud were removed partially from PEG samples. A theoretical detection threshold of 5 × 10⁵ RNA copies of H5N1 virus per 30 g of solid mud could be obtained by elution. The overall method has proved successful for detecting H5N1 virus contamination of mud specimens collected during outbreak investigations of avian influenza in Cambodia.     

Peritoneal dialysis for ESRD patients: financial aspects

Peritoneal dialysis (PD) is as least as good as hemodialysis (HD) for the treatment of end stage kidney disease, considering morbidity and mortality, and better for quality of life. The best result is obtained when the patient can benefit of the sequential treatment, PD first and then HD if necessary. Furthermore, the cost of a patient treated by PD is less than the cost of the same patient treated by HD, at least in developed countries. But, all around the word, the rate of usage of PD don't grow, or decline. One can expect that, as no medical reason can explain this, the cause is economic. Multiple economics aspects and expenses posts for DP are analyzed, as the results of some financial decisions taken in one country or the other, keeping in mind the French system or reimbursement. We conclude that economic incitations may help for the development of PD, if they don't penalize one of the partners (insurance, clinics, doctors of patients), and if in the same time there is an improvement of the formation and information of doctors and patient.