[Residual levels of pesticides in freshwater fish from Beijing aquatic product markets and health risk assessment].

Health risks by fish consumption were assessed following the investigation of the residual levels of 25 pesticides in four kinds of freshwater fish from 4 aquatic product markets in Beijing using ultrasonic extraction-GC-MS. Eighteen pesticides were detected from the 48 samples collected. Acetochlor (97.9%) and beta-HCH (93.8%) showed high detection rates. The pesticide detected in highest concentration was chlorothalonil (1 779.4 microg x kg(-1)), followed by deltamethrin (620.3 microg x kg(-1)). Coexistence of 2-10 kinds of pesticides in fish was found with the total pesticide concentration in range of 2.7-1932 microg x kg(-1). Based on the averaged fish consumption of Beijing residents, the health risk of the studied pesticides by freshwater fish consumption was calculated as 0.043 43, suggesting a relatively low health risk.

[Coupling AFM fluid imaging with micro-flocculation filtration process for the technological optimization].

Atomic force microscope (AFM) fluid imaging was applied to the study of micro-flocculation filtration process and the optimization of micro-flocculation time and the agitation intensity of G values. It can be concluded that AFM fluid imaging proves to be a promising tool in the observation and characterization of floc morphology and the dynamic coagulation processes under aqueous environmental conditions. Through the use of AFM fluid imaging technique, optimized conditions for micro-flocculation time of 2 min and the agitation intensity (G value) of 100 s(-1) were obtained in the treatment of dye-printing industrial tailing wastewater by the micro-flocculation filtration process with a good performance.

[Characteristics of glycemic excursion in different subtypes of impaired glucose intolerance].

OBJECTIVE: To investigate the characteristics of glycemic excursion of different subtypes of glucose tolerance. METHODS: Assessed by oral glucose tolerance test (OGTT) repeated twice, 81 individuals were divided into 4 groups: normal glucose tolerance (NGT, n = 18), isolated impaired fasting glycemia (IFG, n = 12), isolated impaired glucose tolerance (IGT, n = 19), combined IFG/IGT (n = 11), and newly diagnosed type 2 diabetes mellitus (T2DM, n = 21). And then continuous glucose monitoring system (CGMS) was used for 72 hours to monitor the blood glucose (BG) level before drug intervention. RESULTS: (1) The levels of largest amplitude of glycemic excursions (LAGE), mean blood glucose (MBG), and standard deviation of mean level of blood glucose fluctuation (SDBG) increased gradually with the deterioration of glucose tolerance. The mean amplitude of glucose excursion (MAGE) readout of the IGT group was (3.2 +/- 1.2) mmol/L, significantly higher than that of the NGT group [(1.6 +/- 0.5) mmol/L, P < 0.05], and significantly lower than that of the T2DM group [(5.2 +/- 1.9) mmol/L, P < 0.05]. The level of frequency of glucose excursion (FGE) decreased along with the decrease of glucose tolerance: NGT group [(6.1 +/- 3.4)] > IGT/IFG group [(5.5 +/- 2.5)] > T2DM group [(4.8 +/- 1.8)]. Among the three components of IGR, the IGT group showed highest MAGE (3.2 +/- 1.2) mmol/L and lowest FGE level (4.9 +/- 1.8). (2) The level of absolute mean of daily difference (MODD) increased in the following order: NGT group [(0.8 +/- 0.3) mmol/L], IGT group [(1.1 +/- 0.4) mmol/L], IFG/IGT group [(1.2 +/- 0.4) mmol/L], and T2DM group [(2.0 +/- 1.0) mmol/L] (all P < 0.05). (3) The fasting glucose level deteriorated the most rapidly in the IFG group, while it reached the highest postprandial peak in the IFG/IGT group. The blood glucose curve increased along the order of NGT, I-IGT, IFG/IGT, IFG, and T2DM. (4) When the level of glycosylated hemoglobin (HbA1c) level was less than 7%, the fasting phase of curve virtually coincided with each other among individual groups with different HbA1c levels; however, the postprandial peak separated slightly. When the HbA1C level was between 7.0% and 7.9%, the postprandial peaks of individual groups with different HbA1c levels dispersed markedly. When the HbA1c level was higher than 8%, the fasting blood glucose curve moved upwards significantly with increasing postprandial excursion. CONCLUSION: (1) With the deterioration of glucose regulation, the intraday and day-to-day blood glucose excursions become increasingly fluctuant. (2) The amplitude of glycemic excursion is lower in the NGT group than in the T2DM group, however, the frequency of glycemic excursion is higher in the NGT subject than in the T2DM subjects. The glucose excursion profile of the IGR subjects is between the NGR and T2DM subjects. (3) The characteristics of glucose excursion of the IGT group are similar to those of the T2DM group, and the characteristics of the IFG group are similar to those of the NGT group. (4) The loss of postprandial glycemic control precedes evident deterioration in fasting phase of IGR.

Microvascular patterning is controlled by fine-tuning the Akt signal.

We investigated the functions of Akt during vascular development and remodeling by using an inducible endothelial cell-specific driver of the dominant-active myrAkt. We found that sustained signaling in response to overexpression of myrAkt led to embryonic lethality, edema, and vascular malformations. In addition to the morphological malformations, the vascular phenotype was consistent with a failure in remodeling, such that the normal patterning and vessel hierarchy was disturbed. Examination of the well studied retinal vasculature during the remodeling phases revealed that transient expression of myrAkt was capable of altering the normal response to oxygen-induced remodeling without causing vascular malformations. These findings suggest that physiological levels of Akt signaling modulated microvascular remodeling and support the hypothesis that, although Akt may be required for vascular growth and homeostasis, appropriate down-regulation is also an essential aspect of normal vascular patterning.

RhoB controls Akt trafficking and stage-specific survival of endothelial cells during vascular development.

Blood vessel formation is a complex morphological process that is only beginning to be understood at the molecular level. In this study, we demonstrate a novel and critical role for the small GTPase, RhoB, in vascular development. RhoB null mice have retarded vascular development in the retina characterized by altered sprout morphology. Moreover, pharmaceutical means to deplete RhoB in neonatal rats is associated with apoptosis in the sprouting endothelial cells of newly forming vessels. Similarly, acute depletion of RhoB by antisense or dominant-negative strategies in primary endothelial cell culture models led to apoptosis and failures in tube formation. We identified a novel link between RhoB and the Akt survival signaling pathway to explain these changes. Confocal microscopy revealed that RhoB is highly localized to the nuclear margin with a small percentage found inside the nucleus. Similarly, total Akt is throughout the cell but has increased accumulation at the nuclear margin, and active phosphorylated Akt is found primarily inside the nucleoplasm, where it partially colocalizes with the RhoB therein. We show that this colocalization is functionally relevant, because when RhoB was depleted, Akt was excluded from the nucleus and total cellular Akt protein was decreased in a proteosome-dependent manner. Because the function of RhoB in vivo appears to only be rate limiting for endothelial cell sprouting, we propose that RhoB has a novel stage-specific function to regulate endothelial cell survival during vascular development. RhoB may offer a therapeutic target in diseases such as cancer, diabetic retinopathy, and macular degeneration, where the disruption of sprouting angiogenesis would be desirable.