[Method for determining concentration of dichlorvos in serum by gas chromatography].

OBJECTIVE: To develop a method for determining the concentration of dichlorvos in serum by gas chromatography and to provide a basis for clinical diagnosis and monitoring of dichlorvos poisoning. METHODS: The serum (0.5 ml)collected from patients with dichlorvos poisoning was mixed with ethyl acetate (2.0 ml) and underwent shaking/extraction; the obtained liquid was subjected to standing (5 min) and centrifuging (4000 rpm); the obtained supernatant was collected and blow-dried with nitrogen and was then dissolved in ethanol (50 µl); 1.0 µl of the obtained liquid was collected and loaded into a glass-packed column; gas chromatography was performed using a nitrogen-phosphorus detector. RESULTS: A linear relationship was found when the concentration of dichlorvos in serum was 5.0 ∼ 50.0 µg/ml, with a regression equation of y = 804.13x-691.8 (r = 0.9992). The minimum detectable concentration was 2.0 µg/ml, the recovery rate was 86.8% ∼ 94.5%, the relative standard deviation (RSD) was 4.6% ∼ 5.5%, with an intra-day RSD of 4.52% ∼ 5.21% and an inter-day RSD of 3.56% ∼ 5.52%. CONCLUSION: This determination method is easy to operate, efficient, and accurate, and can be used for quickly diagnosing dichlorvos poisoning and quantitatively evaluating treatment outcome.

[The impact of L-carnitine administration on the serum level of myocardium injury markers in patients with acute carbon monoxide poisoning].

OBJECTIVE: To examine the serum level of myocardial injury markers in patients with carbon monoxide (CO) poisoning, the correlation between these markers and the severity of the disease, and the therapeutic effects of L-carnitine administration. METHODS: 69 patients, chosen from 309 cases of acute carbon monoxide poisoning (ACOP) for abnormally high level of serum myocardial injury markers (myoglobin, Mb; MB isoenzyme of creatine kinase, CK-MB; cardiac troponin-I, cTnI) at the time of admission, were randomly divided into control group (n = 34) and observation group (n = 35). The patients in control group were given Xingnaojing (20 ml/d i.v. drip), and the observation group Xingnaojing (20 ml/d)+L-carnitine (2 g/d i.v. drip), in addition to the conventional oxygen supply and symptom-focused therapy. The plasma concentration of carboxyhemoglobin (HbCO, as index for CO poisoning severity), Mb, CK-MB, and cTnI in these patients were further examined 24 hours, 72 hours and 1 week after the treatment, for difference between the two groups, and the correlation between the serum level of HbCO and the myocardial injury markers. RESULTS: At the time of admission, the incidence of abnormal findings in myocardial injury markers were 2.5% (5/204), 46.8% (36/77) and 100.0% (28/28) in patients with mild (HbCO: 10% ~ 19%), moderate (20% ~ 39%) and severe (≥40%) CO poisoning, respectively. The incidence of abnormal findings in injury markers was significantly correlated to the HbCO concentration (x(2)=170.3549, P < 0.0001). Before the treatment, no significant difference was found in any of the indexes [HbCO: (31.1 ± 17.6)%, (32.3 ± 16.9)%, Mb (µg/L): 154.2 ± 51.8, 165.4 ± 48.6, CK-MB (µg/L): 8.7 ± 3.3, 9.6 ± 3.8), and cTnI (µg/L): 2.7 ± 1.2, 2.8 ± 1.5, all P > 0.05] between the control and observation group. However, it was found in: Mb (24 hours: 74.0 ± 36.5 vs. 97.1 ± 35.8, 72 hours: 40.1 ± 6.8 vs. 69.0 ± 11.2), cTnI (24 hours: 1.9 ± 0.5 vs. 2.3 ± 0.7, 72 hours: 1.2 ± 0.3 vs. 1.8 ± 0.4) both 24 hours and 72 hours after the treatment, and CK-MB, 24 hours after treatment (10.6 ± 4.1 vs. 13.0 ± 3.9) with the values in observation group significantly lower (P < 0.05 or P < 0.01); 1 week after the treatment, the concentration of all the injury markers returned to the normal levels with no significant difference between the two groups. Meanwhile, no significant difference was found between the two groups in HbCO concentration throughout the due-course of the therapy. CONCLUSIONS: The incidence of abnormal findings in serum myocardial injury markers was positively correlated with HbCO concentration after CO poisoning. L-carnitine may protect the myocardium and striated muscles against injury in patients with CO poisoning.

[Monitoring on spatial and temporal changes of snow cover in the Heilongjiang Basin based on remote sensing].

This paper extracted and verified the snow cover extent in Heilongjiang Basin from 2003 to 2012 based on MODIS Aqua and Terra data, and the seasonal and interannual variations of snow cover extent were analyzed. The result showed that the double-star composite data reduced the effects of clouds and the overall accuracy was more than 91%, which could meet the research requirements. There existed significant seasonal variation of snow cover extent. The snow cover area was almost zero in July and August while in January it expanded to the maximum, which accounted for more than 80% of the basin. According to the analysis on the interannual variability of snow cover, the maximum winter snow cover areas in 2003-2004 and 2009-2010 (>180 x 10(4) km2) were higher than that of 2011 (150 x 10(4) km2). Meanwhile, there were certain correlations between the interannual fluctuations of snow cover and the changes of average annual temperature and precipitation. The year with the low snow cover was corresponding to less annual rainfall and higher average temperature, and vice versa. The spring snow cover showed a decreasing trend from 2003 to 2012, which was closely linked with decreasing precipitation and increasing temperature.