Open acid dissolution-Ammonia solution extraction-ICP OES rapid determination of 7 trace metal elements in soil.

To overcome the corrosion of hydrofluoric acid on the ICP OES injection system in the acid dissolution system, this paper makes some improvements based on the traditional open digestion. The improved method does not require the complete removal of hydrofluoric acid. After appropriate digestion of the sample with a mixed acid, the solution can be transferred to a colorimetric tube containing ammonium hydroxide solution to give the final volume for analysis. In this paper, two-point standard curves are plotted using soil standards and process blanks, which is not only convenient but also overcomes the interference of the matrix effect. Through continuous experiments, the preferred ratio of mixed acid is 3 mL nitric acid + 5 mL hydrofluoric acid, and the concentration of ammonia solution is 0.5%. The spectral lines of the measured elements V (292.4), Cr (283.5), Co (228.6), Ni (231.6), Cu (324.7), Zn (213.8) and Pb (220.3) were determined. The method quantification limits of the seven measured elements V, Cr, Co, Ni, Cu, Zn and Pb were 0.909, 4.32, 0.269, 0.261, 0.968, 3.69 and 2.64 µg g-1, respectively, and the precision was 3.5%, 5.2%, 4.8%, 2.4%, 6.1% and 4.5%, respectively. After processing six national standard materials according to the experimental method, the measured values of each measured element were basically in agreement with the certified values, indicating that this method is fully feasible for the measurement of V, Cr, Co, Ni, Cu, Zn and Pb in soil. This method greatly improves the efficiency of pretreatment and is particularly suitable for analysing large batches of samples.

The Clinical Diagnostic Value of F-FDG PET/CT Combined with MRI in Pancreatic Cancer.

Pancreatic cancer is a common gastrointestinal tumor with increasing morbidity and mortality, and it is difficult to differentiate it from chronic mass pancreatitis. F-18-fluorodeoxyglucose positron emission tomography/computed tomography (F-FDG PET/CT) can be used for diagnosis of pancreatic cancer, staging, radiotherapy planning, evaluation of efficacy and recurrence, and differentiation from posttreatment fibrosis but the sensitivity and specificity of diagnosis of chronic pancreatitis are poor. Magnetic resonance imaging (MRI) not only shows the morphology, location, and size of organs and lesions but also has the advantages of low radiation, high soft tissue contrast, and multiparameter imaging, which can help determine the nature of occupying pancreatic lesions. In this study, the watershed algorithm (WA) was used to segment the abdominal images to extract images of pancreatic cancer cells and to compare the value of F-FDG PET/CT combined with MRI in the diagnosis of pancreatic occupying lesions.

Using protein misfolding cyclic amplification generates a highly neurotoxic PrP dimer causing neurodegeneration.

Under the "protein-only" hypothesis, prion-based diseases are proposed to result from an infectious agent that is an abnormal isoform of the prion protein in the scrapie form, PrP(Sc). However, since PrP(Sc) is highly insoluble and easily aggregates in vivo, this view appears to be overly simplistic, implying that the presence of PrP(Sc) may indirectly cause neurodegeneration through its intermediate soluble form. We generated a neurotoxic PrP dimer with partial pathogenic characteristics of PrP(Sc) by protein misfolding cyclic amplification in the presence of 1-palmitoyl-2-oleoylphosphatidylglycerol consisting of recombinant hamster PrP (23-231). After intracerebral injection of the PrP dimer, wild-type hamsters developed signs of neurodegeneration. Clinical symptoms, necropsy findings, and histopathological changes were very similar to those of transmissible spongiform encephalopathies. Additional investigation showed that the toxicity is primarily related to cellular apoptosis. All results suggested that we generated a new neurotoxic form of PrP, PrP dimer, which can cause neurodegeneration. Thus, our study introduces a useful model for investigating PrP-linked neurodegenerative mechanisms.

[Effects of IFN alpha on the expressions of Collagen I and transforming growth factor beta 1 in hepatic stellate cell activated by PDGF-BB].

OBJECTIVE: To investigate the effect of IFN alpha on the expressions of Collagen I and TGF beta 1 in hepatic stellate cell activated by PDGF-BB. METHODS: Hepatic stellate cells (rHSC-99) treated with IFN alpha of different concentration (0, 0.0125, 0.025, 0.050, 0.100, 0.200, 0.400 ng/ml). The cell viability of HSC was measured by MTT. The levels of Col-I mRNA and TGF beta 1 mRNA were measured by the quantitative reverse-transcription polymerase chain reaction (RT-PCR). RESULTS: (1) When HSC was exposed in PDGF-BB, the cell viability of HSC (1.35 +/- 0.22) was higher than that of the control group (0.890 +/- 0.12) (F = 16.311, P less than 0.05), indicating that PDGF-BB can promote the cell viability of HSC. When HSC was exposed to both PDGF-BB and different concentration of IFN alpha (0.025, 0.05, 0.1, 0.2, 0.4 ng/ml), the cell viability of HSC (0.840 +/- 0.18, 0.450 +/- 0.15, 0.260 +/- 0.01, 0.330 +/- 0.07, 0.30 +/- 0.06) were lower than that of the control group (0.890 +/- 0.12) (F = 7.430, P less than 0.05), indicating that the cell viability of HSC was inhibited when HSC was exposed to both PDGF-BB and different concentrations of IFN alpha. Furthermore, within the range of 0.025 ng/ml to 0.1 ng/ml, the effect of IFN alpha was dose-dependent. (2). The relative expression values of Col-I mRNA in different groups of (0.05, 0.1, 0.2 ng/ml) IFN alpha +PDGF-BB are (0.940 +/- 0.19, 0.610 +/- 0.12, 0.520 +/- 0.02), which were lower than those in the control group (1.410 +/- 0.01) (F = 127.921, P less than 0.05). The relative expression values of TGF beta 1 mRNA in different groups of (0.05, 0.1, 0.2 ng/ml) IFN alpha +PDGF-BB are (1.180 +/- 0.06, 1.150 +/- 0.10, 1.390 +/- 0.04), again were lower than those in the control group (1.620 +/- 0.12) (F = 82.115, P less than 0.05). These results indicated that the expression of Col-I mRNA and TGF beta 1 mRNA was remarkably inhibited when HSC was exposed in both PDGF-BB and IFN alpha. CONCLUSION: The cell viability of HSC and the expression of Col-I mRNA and TGF beta 1 mRNA is remarkably inhibited when HSC is exposed in both PDGF-BB and IFN alpha, and the inhibition is dose-dependent.