[Spatial Distribution and Source Analysis of Soil Heavy Metals in a Small Watershed in the Mountainous Area of Southern Ningxia Based on PMF Model].

In order to ascertain the distribution characteristics of soil heavy metal pollution and main pollution sources in a small watershed in the southern mountainous area of Ningxia and to ensure the quality of the soil environment, the contents of heavy metals Pb, Ni, Zn, Mn, Cu, Cr, and Cd in 260 surface soil samples (0-20 cm) were collected and determined. Based on the soil background value in Ningxia, the soil heavy metal pollution status and potential ecological risk were evaluated through the single factor index, Nemera composite index, and potential ecological risk index, and the method of combining positive definite matrix factor analysis (PMF) and Kriging interpolation was used to analyze the soil heavy metal spatial distribution and source. The results showed that the average contents of ω(Pb), ω(Ni), ω(Zn), ω(Mn), ω(Cu), ω(Cr), and ω(Cd) were 31.42, 36.22, 62.89, 546.18, 22.26, 61.90, and 0.18 mg·kg-1, respectively. Except for Ni, the other elements were higher than the background value of Ningxia but lower than the background value of agricultural soil pollution risk selection criteria and green food environmental quality standards. The Nemera composite index showed that the proportions of mild, moderate, and severe heavy metal pollution were 71.92%, 19.23%, and 1.54%, respectively. The potential ecological risks were mainly minor risks, accounting for 98.85%. In addition, there were a very small number of samples with medium potential ecological risk levels, accounting for 1.15% of the total number of samples. Source analysis showed that the main sources of soil heavy metals in the small watershed in the mountainous area of southern Ningxia were mixed sources of fertilization and industrial emissions (12.6%), agricultural activity sources (23.5%), natural parent material sources (27.6%), mixed sources of pesticide use and mining development emissions (17.7%), and atmospheric deposition sources (18.6%).

[In vivo labeling of rat neural progenitor cells in subventricular zone with superparamagnetic iron oxide for tracking of magnetic resonance imaging].

OBJECTIVE: To explore the feasibility of in vivo labeling of adult rat neural progenitor cells (NPCs) in subventricular zone (SVZ) with superparamagnetic iron oxide particles (SPIOs) for tracking of magnetic resonance imaging (MRI). METHODS: A total of 7 SD rats were stereotactically injected with 3 µl SPIOs (7 mg Fe/ml) into anterior horn of right lateral ventricle and then 5-bromo-2'-deoxyuridine (BrdU) was injected intraperitoneally once daily for 1 week. MRI was performed at 1, 3, 7 and 14 days post-injection. After the final MRI scan, all rats were transcardially perfused and their brains removed and fixed. The sections were processed for Prussian blue iron staining and Prussian blue plus BrdU immunohistochemical staining. RESULTS: In all experimental animals, SPIOs were predominantly located in the anterior horn of right lateral ventricle and partial SPIOs entered the ventricular system. A needle path and a distribution of SPIOs along rostral migratory stream (RMS) towards olfactory bulb (OB) were depicted at the sagittal view of T2(*)WI, moderate MR artifact was visible and SPIOs tracking NPCs were successful (success rate of 100%). The result of staining showed SPIOs labeling NPCs were effective. And the labeling rates were 75.5%, 42.3%, 23.6% in SVZ, RMS and OB respectively. CONCLUSION: Effective in vivo labeling of adult rat NPCs in SVZ with SPIOs is feasible. And dynamical migration of labeling NPCs along RMS towards OB may be visualized on MRI.

1H-MRS assessment of the therapeutic effect of bilateral intraventricular BDNF infusion into APP/PS1 double transgenic mice.

Alzheimer's disease (AD) is a neurodegenerative disorder characterized by extracellular accumulation of amyloid deposits. Brain-derived neurotrophic factor (BDNF) is a neurotrophic factor whose levels have been shown to be decreased in AD brains. BDNF supplementation can offer improvement in the course of AD. However, the means of assessment are still relatively limited. In the present study, 1H-MRS was used to evaluate the therapeutic effects of bilateral intraventricular BDNF infusion into Alzheimer's disease APP/PS1 double transgenic mice. For comparison to the 1H-MRS observations, Fluoro-Jade B staining and immunofluorescence for beta amyloid peptides (Aß), glial fibrillary acidic protein, and tropomyosin-related kinase B (TrkB) were also performed. Our results showed that N-acetylaspartate (NAA) levels increased and myoinositol levels decreased in the BDNF group compared with the PBS group. However, the BDNF group NAA level was still lower than the control group at 6 weeks after infusion. These changes correlated with increased immunoreactivity for TrkB, decreased compact Aß peptide containing plaques, and decreased Fluoro-Jade B-positive cells in the BDNF-infused mice compared to vehicle controls. These findings demonstrate that 1H-MRS may be a promising means of evaluating the therapeutic effects of BDNF on AD.

[Effects of neural stem cells transplanted into an animal model of Alzheimer disease on Aß plaques].

OBJECTIVE: To explore the effects on Aß plaques of neural stem cells transplanted into an Alzheimer disease mouse model. METHODS: A total of twenty 12-months-old APP+PS1 double transgenic AD mice were randomly divided into two groups.One group received neural stem cells transplantation, that was NSC group, another mice received an equal quantity 0.01 mol/L PBS, as positive control group. After 5 weeks transplantation, the total number of Aß plaques examined by immunohistochemistry, the ratio of compact of Aß plaques by TS staining, and whether NSCs migrate into Aß plaques by immunofluorescence monitoring. RESULTS: There was no difference in total number of Aß plaques between NSC group (181 ± 12) and PBS (179 ± 14) group after transplantation (P > 0.05). There was no difference in the number of TS+ plaques between NSC group (54.9%) and PBS (55.7%) group after eight weeks NSCs transplantation (P > 0.05). (2) However, engrafted NSCs showed partial chemotaxis toward Aß plaques. CONCLUSION: NSCs transplantation did not have a significant impact on Aß plaques of AD mice, but the tropism of engrafted NSCs may be capable of replacing lost or damaged cells and reverse the course of AD mice in some extent.

[Effects of low-dose X-ray on morphology of neuron and expression of microtubule associated protein-2 in hippocampus of young rats].

OBJECTIVE: To explore the effects of a continuous low-dose of X-ray upon neuronal morphology and expression of microtubule associated protein-2 (MAP-2) in hippocampus of young rats. METHODS: A total of 18 Sprague-Dawley rats aged 35 days were randomly divided into two irradiated groups and one control group (n = 6 each). The irradiated groups received different doses of 0.2 mGy/d, 1.0 mGy/d for 7 consecutive days while the control group sham radiation. The hippocampal pyramidal cell was observed by HE staining, the expression of MAP-2 by immunohistochemistry and Western blot, and the morphologies of microtubule and synapse in CA1 by electron microscopy. RESULTS: (1) The phenomenon of neurodegeneration was observed in the 1.0 mGy group while the control and 0.2 mGy groups were normal; (2) the average optical density of positive MAP-2 protein significantly decreased in the 1.0 mGy group (0.242 ± 0.017) in the region of CA1 versus the control group (0.282 ± 0.016) (F = 14.419, P = 0.005). And the average optical density of positive MAP-2 significantly increased in the 0.2 mGy group (0.331 ± 0.017) compared with the control group (F = 21.700, P = 0.002). The expression of total MAP-2 significantly decreased in the 1.0 mGy group (0.332 ± 0.001) versus the control group (0.370 ± 0.012) (F = 28.055, P = 0.000). And the expression of total MAP-2 significantly increased in the 0.2 mGy group (0.455 ± 0.018) versus the control group (F = 61.974, P = 0.002); (3) there were the reduction of microtubule and the damage of postsynaptic density (PSD) in the 1.0 mGy group in hippocampal CA1. Increased microtubule and normal synapses were found in the 0.2 mGy group in hippocampal CA1. CONCLUSION: The expression of MAP-2 is strongly associated with the integrity of hippocampal neurons in young rats. The 0.2 mGy group may promote the proliferation of hippocampal microtubule in hippocampus and further promote the expression of MAP-2. And the damage of microtubule and PSD on neuron could reduce the expression of MAP-2 in the 1.0 mGy group.

Malignant mesothelioma presenting as a giant chest, abdominal and pelvic wall mass.

Malignant mesothelioma (MM) is a relatively rare carcinoma of the mesothelial cells, and it is usually located in the pleural or peritoneal cavity. Here we report on a unique case of MM that developed in the chest, abdominal and pelvic walls in a 77-year-old female patient. CT and MRI revealed mesothelioma that manifested as a giant mass in the right flank and bilateral pelvic walls. The diagnosis was confirmed by the pathology and immunohistochemistry. Though rare, accurate investigation of the radiological features of a body wall MM may help make an exact diagnosis.

[The comparative study on high field MRI and pathology of Alzheimer's disease transgenic mice].

OBJECTIVE: To observe and investigate the neuroimaging characters in early progression of transgenic Alzheimer's disease (AD) mice model, and make sure the diagnosis value of 7.0 T high field magnetic resonance microimaging (MRMI). METHODS: APP/PS-1 transgenic mice aged 3, 6, 9 months and the same aged wild type mice were each divided into 6 groups (6 mice in every groups) based on age. The mice brains were scaned with 7.0T high magnetic field MR. Then the mice were killed. The Aß immunohistochemistry examination was analyzed in the mice brains specimens, and pathological changes were in comparison with the T(2) weighted imaging in the mice brains. RESULTS: There were a few Aß plaques in the brains of 6 months APP/PS-1 transgenic mice, while Aß plaques were increased both in number and volume in the cerebral cortex and hippocampus of 9 months AD mice. The brains of APP/PS-1 double transgenic mice of 3, 6 months and the control group mice were not showed intensity loss on T(2) weighted MR images, while the signal intensity loss was visualized in the cerebral cortex and hippocampus of 9 months AD mice. CONCLUSION: 7.0T high magnetic field MR could display Aß plaques in the brains of APP/PS-1 double transgenic mice of 9 months and it is helpful to diagnosis early AD.

[The effect of continuous low doses X-ray on the proliferation of pyramidal cell in hippocampus CA1 in prenatal rats].

OBJECTIVE: To explore the effect of low doses X-ray on proliferation of hippocampal pyramidal cell in the area of CA1 in prenatal rat and its relevant mechanism. METHODS: A total of 25 pregnant rats were randomly divided into four experimental groups and one control group. The experimental groups, in a duration of consistent 18 days, respectively received different doses as follows: 0.015 mGy/d, 0.03 mGy/d, 0.06 mGy/d and 0.09 mGy/d. The control group received sham radiation. To observe the density and width of hippocampal pyramidal cell in the area of CA1 by HE stained and observe the expression of the ERK1/2 by IHM. RESULTS: (1) Except C group, all other groups presented increment in width of the level of hippocampal pyramidal cell, compared with C group; H group, M group, L1 group and L2 group were higher than that (F value respectively were 8.475, 33.42, 14.395, 44.955; P value respectively were 0.002, 0.048, 0.030, 0.012). But the phenomenon of inhomogeneity in width in H group was observed, at the same time, the density of cell in H group became looser (F = 4.466, P = 0.017). (2) The expression of ERK1/2 in the hippocampus CA1 was seen in cytoplasm of every group, the average optical density of positive ERK1/2 protein significantly increased in L1 group and L2 group, compared with control group respectively (F value respectively were 4.561, 4.103, P value respectively were 0.044, 0.035). CONCLUSION: Low doses X-ray could promote proliferation of hippocampus CA1 cell in prenatal. The reason could be the increment of the ERK1/2 protein induced by X-ray. When the doses reached 0.09 mGy/d, the excesses proliferation phenomenon was observed.