Dialkyl phosphates in amniotic fluid as a biomarker of fetal exposure to organophosphates in Crete, Greece; association with fetal growth.

The aim of this study was to evaluate fetal exposure to organophosphate pesticides (OPs) by measuring their non-specific dialkyl-phosphate metabolites (DAPs) in amniotic fluid (AF), and to examine the potential association between prenatal exposure and fetal growth. AF samples were collected from 415 women during the second gestational trimester. The determined OPs metabolites were DMP, DMTP, DEP, DETP, and DEDTP. DAPs were extracted by liquid-solid extraction, derivatized and analyzed by gas chromatography-mass spectrometry. 97.8% of AF samples were positive for at least one DAP. DAPs levels did not differ between urban and rural areas. Macrosomic neonates have significantly higher sum levels of DMPs (p=0.043), which exerted a linear positive association with birth-weight centile (b=4.43, p=0.016). Conclusively, as DAPs are detectable in AF they may be used as a potential biomarker of fetal exposure to OPs. Sum levels of DMPs appear to be associated with birth weight independently of other covariates.

Is hair analysis for dialkyl phosphate metabolites a suitable biomarker for assessing past acute exposure to organophosphate pesticides?

In the present paper, the possibility to use dialkyl phosphate metabolites (DAPs) hair segmental analysis as a biomarker of past acute exposure to organophosphates is examined. Hair samples of four acute poisoning survivors were collected and segmental hair analysis was performed. The total hair samples were divided to 1 cm segments and analysed by gas chromatography-mass spectrometry (GC-MS) for the presence of four DAP metabolites, dimethyl phosphate (DMP), diethyl phosphate (DEP), diethyl thiophosphate (DETP) and diethyl dithiophosphate (DEDTP). Results were examined under the light of pesticide type and time of hair sample collection. Although DAPs were detected all along the hair shaft, higher concentrations (peaks) were detected in the segments proximate to the suicide period. It was also observed that the elevated concentrations of the present metabolites corresponded to the ones produced by the ingested parent compound. Conclusively, measurements of DAPs in the appropriate hair segments of OP-poisoned patients can be used for assessing past acute exposure to organophosphates in certain cases.

Assessment of levels of organochlorine pesticides and their metabolites in the hair of a Greek rural human population.

We present the assessment of chronic exposure of the rural population of Helia Peloponnesus, Greece to banned organochlorine pesticides, hexachlorocyclohexane (HCH), and 1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane (DDT), using hair analysis. A total of 222 head hair samples were collected and analyzed for the presence of those organochlorine pesticides and their metabolites or isomers. Gas chromatography coupled to mass spectrometry was used to measure the levels of the pollutants. The median concentrations of alpha-HCH, hexachlorobenzene, lindane, ortho para 1,1-dichloro-2,2-bis-(4-chlorophenyl)ethylene (opDDE), para para 1,1-dichloro-2,2-bis(4-chlorophenyl)ethylene (ppDDE), ortho para 1,1-dichloro-2,2-bis(4-chlorophenyl)ethane (opDDD), para para 1,1-dichloro-2,2-bis(4-chlorophenyl)ethane (ppDDD) + ortho para 1,1,1-trichloro-2,2-bis(4-chlorophenyl)-ethane, and para para 1,1,1-trichloro-2,2-bis(4-chlorophenyl)-ethane were determined at 40.4, 19.7, 124.2, 6.2, 7.8, 73.1, 8.0, and 5.7 pg/mg. The median concentration of total HCHs and DDTs were 117.8 pg/mg and 9.4 pg/mg, respectively. The levels of total HCHs were much higher than the levels of DDTs in the hair samples of the studied population. This may be attributed to the presence of lindane, a pesticide officially banned in 2002. It is interesting to see that DDTs are still traced in samples despite their use being banned for more than three decades. There was no difference in the levels of the detected pesticides in hair sampled from men or women. The concentration of HCHs remains high and relatively stable across the age groups, suggesting constant exposure until very recently. The concentration of the total DDTs and the parent compound, pp-DDT presents a statistically significant decreasing trend across the age groups.

Factors affecting fracture healing after intramedullary nailing of the tibial diaphysis for closed and grade I open fractures.

As there is little information on the factors that influence fracture union following intramedullary nailing of the tibia we retrospectively investigated patient-, injury- and treatment-related factors in 161 patients with closed or grade I open fractures of the tibial diaphysis. The patients were reviewed until clinical and radiological evidence of union at a mean of 13.3 months (4 to 60). Multivariate statistical analysis using a Cox proportional hazards model showed that the risk of failure of union increased by 2.38 times for highly comminuted fractures, by 3.14 times when nail dynamisation was applied, and by 1.65 times when the locking screws failed. In fractures with no or only minimal comminution the risk of nonunion increased if the post-reduction gap was > or = 3 mm.

Monitoring of pesticide residues in fresh peaches produced under conventional and integrated crop management cultivation.

The frequency and severity of crop protection product (pesticide) contamination of peaches grown conventionally were compared with those of peaches grown by integrated crop management (ICM). The peach samples (n = 150) were collected preharvest (June-August 2001) from both conventional (n = 55) and ICM (n = 95) cultivations from the Pella and Imathia districts of Macedonia, Northern Greece. The residue levels of selected insecticides, fungicides and acaricides in peach samples were determined by gas chromatography-mass spectrometry following solid-phase extraction. The concentrations of all detected pesticides were lower than the maximum residue limits (MRLs) in all peach samples grown with the ICM system (p<0.001). However, chlorpyrifos residues at levels higher than the MRLs were detected in four peach samples (i.e. 7% of the total samples) grown by the conventional system. Comparing the results for both cultivation methods with the reported average percentage (3.6%) of fruit samples with pesticide residues above the MRLs (European Union report for Greece in 2001), it was concluded that the initial implementation of the ICM in Greece was successful. The present study indicates that ICM cultivation has a higher efficiency in terms of product safety and quality. Furthermore, the results suggest that the application of conventional cultivation requires continuous monitoring of various crop protection product levels.

Expression of proliferating cell nuclear antigen (PCNA) in multiple myeloma: its relationship to bone marrow microvessel density and other factors of disease activity.

The expression of proliferating cell nuclear antigen (PCNA) was studied in plasma cells in bone marrow biopsies from patients with multiple myeloma (MM) using a double immunostaining method. In the same samples, microvessel density (MVD), after staining with anti-CD34 antibodies, was determined before and after chemotherapy. The correlation of PCNA expression and MVD with other myeloma parameters (clinical stage, bone marrow plasma cell infiltration and serum interleukin-6 (IL-6)) was also investigated. The study population included 51 newly diagnosed MM patients, 15 patients in plateau phase after treatment and 15 normal controls. Pretreatment mean +/- SE values of PCNA, MVD, plasma cell infiltration and serum IL-6 were significantly higher than post treatment values and controls. Pretreatment PCNA expression correlated significantly with bone marrow MVD (p<0.05) plasma cell infiltration (p<0.01) and IL-6 (p<0.01). These findings show that the proliferative activity of plasma cells is related to the angiogenic activity in the bone marrow of multiple myeloma patients. Both PCNA and MVD correlate with markers of disease activity thus may provide additional information when included in the initial evaluation of myeloma bone marrow biopsies.

Three-year study of fenthion and dimethoate pesticides in olive oil from organic and conventional cultivation.

Residues of fenthion and dimethoate pesticides were determined in organic and conventional olive oils by liquid-liquid and solid-phase extractions with subsequent gas chromatography and mass spectrometric analysis. The olive oil samples were collected from Crete during 1997-99. The average concentrations of fenthion in conventional olive oils were 0.1222, 0.145 and 0.1702 mg x kg(-1), and for dimethoate were 0.0226, 0.0264 and 0.0271 mg x kg(-1) for 1997, 1998 and 1999, respectively. The average concentrations of fenthion in organic olive oils were 0.0215, 0.0099 and 0.0035 mg x kg(-1) for 1997, 1998 and 1999, while for dimethoate they were 0.0098, 0.0038 and 0.0010 mg x kg(-1), respectively. All the olive oils contained residue levels lower than the maximum residue levels according to the FAO/WHO Codex Alimentarius. The organic olive oil contained significantly lower concentrations of the two pesticides. The levels of fenthion and dimethoate in organic olive oils exhibited a decreasing trend following the implementation of the new cultivation method. We propose procedures that should be established in the organic cultivation in order to maximize its effectiveness.

In vitro study of oxytetracycline adsorption on activated charcoal.

In vitro adsorption experiments simulating pH in gastric environment and using Langmuir isotherm, showed that 408 mg of oxytetracycline was adsorbed per gram of activated charcoal. Langmuir isotherm fitted adsorption data better than a Freundlich isotherm. Freundlich isotherm showed a specific adsorption capacity of 518 mg/g for activated charcoal. Both isotherm parameters indicated a strong oxytetracycline adsorption on activated charcoal in terms of quantity and binding strength. The results demonstrate that the concomitant use of oxytetracyline and activated charcoal should be avoided.

Deactivation of mycotoxins. I. An in vitro study of zearalenone adsorption on new polymeric adsorbents.

This study describes the elimination of zearalenone concentrations in vitro using two new polymeric forms of cross-linked polyvinylpyrrolidone (cryogels of cross-linked PVP). Adsorption of zearalenone was studied under isothermal conditions and simulating pH of intestinal environment. A Freundlich isotherm was used to describe the adsorption data obtained. The results showed significant decrease of zearalenone concentrations, ranging from 33.5-66.2% per 25 mg of polymer. Adsorption capacity (k) was estimated to be higher than that of previously tested adsorbents, including crospovidone. The data indicate the need to investigate structure peculiarities in order to improve mycotoxin deactivation procedures using PVP derivatives.

Experiences with acute organophosphate poisonings in Crete.

Nine human acute poisonings due to intentional ingestion of organophosphorous pesticides are presented. Six of the victims died. Six patients were treated in the Intensive Care Unit (ICU) from 34 h to 45 d, while 3 were found dead by relatives. Two of the patients treated in the ICU fully recovered after 15 and 24 d while the third survivor developed delayed neuropathy. Organophosphate blood levels were determined on admission and during therapy, and in 1 case atropine and pralidoxime levels were also detected. Significant fluctuations of the plasma cholinesterase activity were observed during therapy. Postmortem analysis revealed higher levels of pesticides in organs (eg 23.1 micrograms fenthion/g kidney) and in fat (135.2 micrograms fenthion/g) than in blood (eg 4.8 micrograms fenthion/ml) and vitreous humor. Considerable pesticide was measured in testis (eg 5.8 micrograms fenthion/g, 0.8 micrograms methidathion/g) and uterus (170.5 micrograms malathion/g). Extracorporeal decontamination to enhance pesticide elimination is a therapeutic challenge.