Acute toxicity, 28-day repeated-dose toxicity and toxicokinetic study of timosaponin BII in beagle dogs.

The safety evaluation of timosaponin BII (TBII) in beagle dogs with toxicokinetic study was performed. For the acute oral toxicity study, the minimum lethal dose (MLD) of TBII was more than 2000 mg/kg and suggested the characteristics of absorption saturation. For the 28-day repeated dose oral toxicity and toxicokinetic studies, there was no significant effect on all test parameters except for prolonged APTT in the 60 and 180 mg/kg groups, which recovered after withdrawal. The increase of drug exposure of 180 mg/kg group was not proportional to the increase of administration dose, showing the characteristics of absorption saturation.

Identification of antibacterial and antioxidant constituents of the essential oils of Cynanchum chinense and Ligustrum compactum.

The aim of this research was to determine the chemical composition, antioxidant and antibacterial properties of the essential oils from Cynanchum chinense and Ligustrum compactum and isolation of antioxidant and antibacterial constituents from the essential oils. Thirty-eight components were identified in essential oils. Based on bioactivity-guided fractionation, guaiacol, linalool and 2-phenylethanol were isolated and identified as active constituents. Both L. compactum flower oil and 2-phenylethanol showed high antibacterial performance, with inhibition zone from 22.8 ± 0.8 to 11.9 ± 2.0 mm at highest concentration, and minimum inhibitory concentration values ranging from 0.25% to 1%. In both DPPH and ABTS assay, the active constituent guaiacol (IC50 = 4.15 ± 0.72 and 9.12 ± 0.98 µg mL(-1), respectively) exhibited high antioxidant activity, and the oils showed moderate antioxidant activity. These results indicate potential efficacy of active constituents and essential oils of L. compactum and C. chinense to control food-borne pathogenic and spoilage bacteria.

[Effect of toluene diisocyanate on lung function of workers].

OBJECTIVE: To investigate the effect of long-term exposure to toluene diisocyanate (TDI) on the lung function of TDI-exposed workers. METHODS: A factory was selected for this occupational epidemiological investigation. The workers who were exposed to TDI and had complete physical examination records in recent 3 years were the exposed group (n = 45), while the company's administrative staff, logistics staff, and other non-TDI-exposed workers who had complete physical examination records in recent 3 years were the control group (n = 47). The two groups were compared in terms of lung function indices. RESULTS: Compared with the control group, the 2009 exposure group had significantly lower forced expiratory volume in one second (FEV1.0), FEV1.0/forced vital capacity (FVC), and maximal expiratory flow at 25% of FVC (MEF25) (P < 0.05), the 2010 exposure group had significantly lower FEV1.0, FEV1.0/FVC,maximum voluntary ventilation (MVV), and maximal expiratory flow at 50% of FVC (MEF50) (P < 0.05), and the 2011 exposure group had significantly lower FEV1.0, FEV1.0/FVC, peak expiratory flow (PEF), MEF25, and MEF50 (P < 0.05). CONCLUSION: Long-term exposure to TDI can lead to certain impairment of lung function in workers, which may be reflected by decreased lung function indices such as vital capacity, FVC, FEV1.0, FEV1.0/FVC, PEF, and MVV.

[Determination of 2, 4-toluenediamine in urine by gas chromatography].

OBJECTIVE: To establish a method for determining the content of 2,4-toluenediamine, a urinary metabolite of toluene diisocyanate, by gas chromatography. METHODS: Urine samples were collected, and acidification, extraction, derivatization, separation with a capillary column, and detection with an electron capture detector were performed. The target compound was qualified by retention time and quantified by peak area. RESULTS: The concentration of 2, 4-toluenediamine showed a linear relationship with peak area within 0.0∼40 ng/ml, with a correlation coefficient 0.9995; the limit of detection was 0.44 ng/ml, the lower limit of quantification was 1.47 ng/ml, the relative standard deviation was 1.85%∼4.05%; the recovery rate was 97.98%∼99.28%. CONCLUSION: The method has the advantages of high sensitivity and high accuracy and can be used for determination of 2, 4-toluenediamine in urine.

[Immunity of peritoneal monocytes against Plasmodium yoelii infected erythrocytes].

OBJECTIVE: To test the immunity of peritoneal monocytes against Plasmodium yoelii infected red blood cells (target cells). METHODS: Saponinized Plasmodium yoelii infected red blood cells (SPRBC, Ghost erythrocyte) were used to immunize mice i.p twice. Three weeks later, the infected red blood cells were injected i.p.; 90 min later, the total peritoneal cells were isolated and washed for scanning electromicroscopy to observe the effects of the peritoneal monocyte to the target cell. RESULTS: The peritoneal cells of the immunized mice were activated after 90 min of the challenge of target cells. The size of the cell was not even and the pili on the cell surface turned to be long and densed. Cell interconnections were found among the cells. In some peritoneal monocytes, their cell plasma were scattered (omlette-like) or with the shape as "cellular bomb". The scattered or the sheeted pili and spredding cell plasma could adhere to the target cells which were perforated densely and damaged. CONCLUSION: The protective adaptive immunity exists in the peritoneal monocytes of immunized mice.

[Morphological characteristics of Plasmodium yoelii schizonts in ghost erythrocytes].

OBJECTIVE: To observe the morphological characteristics of Plasmodium yoelii schizogony in their ghost erythrocytes. METHODS: Saponify, hypotonic shock, and electron microscopy were used to observe the different fashions of erythrocytic parasites and their characteristic organellae in ghost erythrocytes. RESULTS: The malarial parasites and their fine structures were dramatically well preserved in the ghost erythrocytes, such as the ring-like early trophozoites, the brassiere-like early schizonts, the emerging buds on the surface of late schizonts, and the grape-cluster like late schizonts. The cytostome, food vacuole, and crystallized malarial pigments were found in the early trophozoites. The proliferations of nucleoplasma and nuclear membrane as well as and the clot-like nuclear division were followed by the budding during the schizogony. CONCLUSION: The saponify technique that makes the erythrocytic malaria parasites and their fine organellae to be dramatically revealed in their ghost erythrocytes, may be a useful method in the Plasmodium biological research and anti-malaria immunological researches.

[Protective immune mechanisms induced by cellular vaccine made of the erythrocytic Plasmodium yoelii].

OBJECTIVE: To explore the characteristics of protective immunity against Plasmodium yoelii (P.y.) infection by asexual blood-stages cellular vaccine. METHODS: The particulate vaccines were constructed by saponin or double-distilled-water lysed parasitic red blood cells and inoculated into BALB/c mice by intraperitoneal injection (i.p.). Each group was challenged by the lethal erythrocytic P.y. parasites, and then their parasitemia and survival rates were detected. Expressions of interleukin-4 (IL-4) and interferon-gamma (IFN-gamma) were detected by RT-PCR. ELISA showed the serum antibodies against the malaria challenge and their-subclasses. Special membrane protein was recognized by immunofluorescence assay. RESULTS: The vaccination with saponified erythrocytic parasites protected the immunized mice against P.y. challenge, while double-distilled-water lysed vaccine did not (P < 0.01). This protection was characterized by the increase of both IFN-gamma/IgG2a and IL-4/IgG1. Meanwhile, MHC class I alpha chain molecule was recognized on the membrane of infected-erthythrocyte. CONCLUSION: Saponified P.y. asexual blood-stage cellular vaccine has a significantly high protective immunity against this lethal P.y. malaria, and the immunity may be associated with the expression levels of IgG2a and IFN-gamma. MHC class I alpha chain on infected erythrocytes may play an important role in the successful immunization.