Analysis of serum levels of organochlorine pesticides and related factors in Parkinson's disease.

BACKGROUND: There is evidence that environmental factors contribute to the onset and progression of Parkinson's disease (PD). Pesticides are a class of environmental toxins that are linked to increased risk of developing PD. However, few studies have investigated the association between specific pesticides and PD, especially in China, which was one of the first countries to adopt the use of pesticides. METHODS: In this study, serum levels of 19 pesticides were measured in 90 patients with PD and 90 healthy spouse controls. We also analyzed the interaction between specific pesticides and PD. In addition, the association between pesticides and clinical features of PD was also investigated. Finally, we investigated the underlying mechanism of the association between pesticides and PD. RESULTS: Serum levels of organochlorine pesticides, which included α-hexachlorocyclohexane (HCH), ß-HCH, γ-HCH, δ-HCH, propanil, heptachlor, dieldrin, hexachlorobenzene, p,p'-dichlorodiphenyltrichloroethane and o,p'-dichloro-diphenyl-trichloroethane were higher in PD patients than controls. Moreover, α-HCH and propanil levels were associated with PD. Serum levels of dieldrin were associated with Hamilton Depression Scale and Montreal Cognitive Assessment scores in PD patients. In SH-SY5Y cells, α-HCH and propanil increased level of reactive oxygen species and decreased mitochondrial membrane potential. Furthermore, propanil, but not α-HCH, induced the aggregation of α-synuclein. CONCLUSIONS: This study revealed that elevated serum levels of α-HCH and propanil were associated with PD. Serum levels of dieldrin were associated with depression and cognitive function in PD patients. Moreover, propanil, but not α-HCH, induced the aggregation of α-synuclein. Further research is needed to fully elucidate the effects of pesticides on PD.

Comparative Pharmacokinetics of High and Low Doses of the Herbicide Propanil in Mice.

We have documented that the herbicide propanil is immunotoxic in mice, and our in vitro tissue culture experiments largely recapitulate the in vivo studies. Laboratory studies on environmental contaminants are the most meaningful when these studies are conducted using concentrations that approximate levels in the environment. Many techniques to measure the distribution and pharmacokinetics (PK) on compounds rely on techniques, such as liquid scintillation counting (LSC) of radio-labeled starting compound, that require concentrations higher than environmental levels. The aim of this study was to compare tissue PK after exposure to propanil concentrations more relevant to levels of exposure to agricultural workers and the general population to concentrations previously reported for laboratory studies. To this end, we conducted a study to measure propanil distribution in three immune organs, using ultrasensitive accelerator mass spectrometry (AMS). We used two doses: the lower dose modeled levels expected in the environment or long-term occupational exposure to low doses, while the higher dose was to model the effects of an accidental exposure. Our results showed that the distribution and PK profiles from these two different concentrations was markedly different. The profile of the high dose (concentration) exposure was indicative of saturation of the detoxifying capability of the animal. In contrast, at the lower environmentally relevant concentration, in vivo concentrations of propanil in spleen, liver, and blood dropped to a very low level by 720 min. In conclusion, these studies highlight the differences in PK of propanil at these two doses, which suggests that the toxicity of this chemical should be re-investigated to obtain better data on toxic effects at doses relevant for humans.

[Simultaneous determination of carbaryl and propanil in human serum and urine by on-line column-switching technique followed by automatic reversed-phase HPLC].

Carbaryl and propanil in human serum and urine were determined by automatic on-line column enrichment technique followed by reversed-phase HPLC with photometric detection. Human serum was filtered through a membrane filter (0.45 micron pore size) and an aliquot of 0.1 ml of the filtrate was diluted with water up to 1 ml. The solution of 0.8 ml was directly injected to automatic HPLC without any preparation. Urine was incubated with beta-glucuronidase/arylsulfate for 16 hours at 37 degrees C. The resultant solution was then filtered through a membrane filter and the filtrate was analyzed by the similar manner as serum. Carbaryl and propanil in the sample solution were concentrated on a pre-conditioned ODS mini-column. After washing the mini-column with 5% methanol, they were separated by an ODS analytical column (Cosmosil 5 C18-MS, 250 x 4.6 mm i.d.) with acetonitrile/water (30:70, v/v) eluent and detected with a UV detector. Carbaryl and propanil in serum were detected at 220 and 210 nm, respectively. On the other hand, in order to separate from blank peaks, carbaryl and propanil in urine were detected at 290 and 260 nm, respectively. The presented HPLC method requires neither manual procedure of solid-phase nor liquid-liquid extraction. Calibration curves for carbaryl and propanil were linear over the range of 5 ng/ml-2 micrograms/ml in both serum and urine. Real serum (ng/ml level) and urine (microgram/ml level) samples were analyzed by the presented HPLC method. Effect of seventeen pesticides on the determination of carbaryl and propanil were investigated. All pesticides did not interfere with the determination except for thiuram.

[Simultaneous determination of propanil, carbaryl and 3,4-dichloroaniline in human serum by HPLC with UV detector following solid phase extraction].

In case of poisoning by herbicide compounded with Propanil (DCPA) and Carbaryl (NAC), we attempted simultaneous solid-phase extractions of DCPA, NAC, and 3,4-dichloroaniline (DCA), a metabolite of DCPA, from the patient's serum, and quantitative analytical method using HPLC-UV detection. With this HPLC method, the quantitative detection limits in the serum are 0.005 microgram/ml for DCPA and DCA and 0.001 microgram/ml for NAC, and the UV spectra of all three compounds could easily be obtained using a diode-array detection limit of 0.05 microgram/ml. When the three compounds were added to serum at concentrations ranging from 0.1-10.0 micrograms/ml, the recovery rates were satisfactory at between 91.1% and 101.9%. On analysis of the serum of patient who had ingested Kusanon A Emulsion, the ingested substance apparently caused an increase in the DCA concentration, which led to the appearance of methemoglobinemia. The possibility that the DCA concentration might be used for prognostic purposes was suggested.