Plutonium in sediments of the Eastern Guangdong coast-its sources and their contribution.

The 239+240Pu activities and 240Pu/239Pu atom ratios of surface sediments from the Eastern Guangdong coast (EGDC) were determined by sector field ICP-MS in order to examine the sources of plutonium (Pu) and quantify their contributions. The 239+240Pu activities in the EGDC ranged from 0.113 to 0.451 Bq kg-1, with an average of 0.225 ± 0.090 Bq kg-1 (n = 17). Consistently high 240Pu/239Pu atom ratios, ranging from 0.218 to 0.274 (average = 0.254 ± 0.014, n = 17), indicate a non-global fallout Pu source in the EGDC. The horizontal distribution of the 240Pu/239Pu atom ratios in the EGDC sediment suggests the non-global fallout Pu is sourced from close-in fallout from the Pacific Proving Grounds (PPG). Using a simple two end-member mixing model, we calculated the relative proportions of Pu from the PPG and global fallout in the EGDC to be 57 ± 9 % and 43 ± 9 %, respectively. Moreover, from the well-defined relationship between 239+240Pu activity and total organic carbon content in sediments and a two end-member mixing model using δ13C, we further calculated the Terr-global fallout (riverine input) and Mar-global fallout (direct atmospheric deposition) to be 11 ± 2 % and 32 ± 6 %, respectively. Finally, from the activity levels and atom ratios of Pu isotopes in the EGDC, we established a baseline for future use in environmental risk assessment related to nuclear power plant operations.

[Effects of pre-moxibustion on expression of phosphorylated Tau protein and related protein kinases in hippocampal CA3 region of AD rats].

OBJECTIVE: To observe the effect of pre-moxibustion at "Baihui"(GV20), "Shenshu"(BL23) and "Zusanli"(ST36) on expression of Tau protein and related protein kinases as glycogen synthase kinase-3ß (GSK-3ß), etc. in the hippocampal CA3 region of Alzheimer's disease (AD) rats, so as to explore its mechanism underlying prevention and treatment of AD cognitive impairment. METHODS: Male SD rats were randomly divided into 4 groups: normal control, sham operation， model and pre-moxibustion，with 9 rats in each group. Rats of the pre-moxibustion group received moxibustion of GV20, BL23 and ST36 for 15 min, once a day, 6 days a week for 3 weeks. After completion of moxibustion, the AD model was reproduced by injection of amyloid beta-peptide 25-35(Aß 25-35) aggregation solution 1 µL (5 µg/µL) into the bilateral hippocampus, rats of the sham operation group received injection of the same dose of normal saline into the hippocampus. The spatial learning-memory ability was detected using Morris water maze test, and changes of the ultrastructure of hippocampal neurons were observed using electron microscope, and those of histopathological changes of hippocampus tissue observed using hematoxylin eosin (H.E.) staining. The expression levels of hippocampal GSK-3ß, p-Tau, CDK5 and Synapsin I proteins were detected by Western blot and immunohistochemistry, respectively. RESULTS: No significances were found between the normal control and sham groups in all the indexes (P>0.05). Compared with the control group, the escape latency of place navigation test of Morris water maze test, expression of GSK-3ß and CDK5 and the immunoactivity of GSK-3ß, CDK5 and p-Tau were significantly increased (P<0.01), and the residence time in the platform quadrant and the number of platform crossing of spatial prob test and the expression of Synapsin Ⅰ significantly reduced in the model group (P<0.01). Following the intervention, the increase of escape latency, expression of GSK-3ß and CDK5 and the immunoactivity of GSK-3ß, CDK5 and p-Tau, and the decrease of residence time in the platform quadrant, number of platform crossing and the expression of Synapsin Ⅰ were reversed in the pre-moxibustion group (P<0.05, P<0.01). Outcomes of ultrastructure and histopathological observations respectively showed edema of hippocampal nerve cells at varying degrees, moderate edema of the cytoplasma, chromatin condensation at the edge of the nucleus, partial mitochondrial vacuole-like degeneration, fracture of tubular crest, edema and expansion of Golgi body, disappearance of polarity, fracture of the rough endoplasmic reticulum, degeneration of ribosome and partial myelin axon and reduced synaptic vesicles in the presynaptic capsule; and reduced number of neurons with shrank body, disappearance of nucleolus and blurred nuclear boundary and vacuole-like degeneration in some of them in the model group, which were relatively milder in the pre-moxibustion group. CONCLUSION: Pre-moxibustion at GV20, BL23 and ST36 plays a role in slowing down the occurrence and development of cognitive impairment in AD rats, which may be related to its functions in inhibiting tau protein hyperphosphorylation and reducing the expression of some related protein kinases in the hippocampus.

Proliferation and differentiation of rat osteoporosis mesenchymal stem cells (MSCs) after telomerase reverse transcriptase (TERT) transfection.

BACKGROUND: The aim of this study was to determine whether MSC are excellent materials for MSCs transplantation in the treatment of osteoporosis. MATERIAL AND METHODS: We studied normal, osteoporosis, and TERT-transfected MSC from normal and osteoporosis rats to compare the proliferation and osteogenic differentiation using RT-PCR and Western blot by constructing an ovariectomized rat model of osteoporosis (OVX). The primary MSC from model rats were extracted and cultured to evaluate the proliferation and differentiation characteristics. RESULTS: MSCs of osteoporosis rats obviously decreased in proliferation ability and osteogenic differentiation compared to that of normal rats. In contrast, in TERT-transfected MSC, the proliferation and differentiation ability, and especially the ability of osteogenic differentiation, were significantly higher than in osteoporosis MSC. CONCLUSIONS: TERT-transfected MSCs can help osteoporosis patients in whom MSC proliferation and osteogenic differentiation ability are weak, with an increase in both bone mass and bone density, becoming an effective material for autologous transplantation of MSCs in further treatment of osteoporosis. However, studies are still needed to prove the in vivo effect, biological safety, and molecular mechanism of TERT-osteoporosis treatment. Additionally, because the results are from an animal model, more research is needed in generalizing rat model findings to human osteoporosis patients.

Donor Age and Cell Passage Affect Osteogenic Ability of Rat Bone Marrow Mesenchymal Stem Cells.

Tissue engineering allows the restoration of pathologically damaged tissues such as cartilage and bone using bio-scaffolds containing functionally active cells. Bone-marrow-derived mesenchymal stem cells (BMSCs) are a promising source of cells for tissue engineering due to their multilineage differentiation potential. However, proliferative and osteogenic abilities of BMSCs, and quantity of stem cells decreases in the bone marrow in aged population. We cultured BMSCs isolated from rats of various ages and evaluated their morphology, activity, and differentiation potential. Cultured BMSCs formed monolayer of fibroblast-like cells and maintained their characteristic morphology for 7-10 generations. Flow cytometry showed that aging of the cultured cell population correlated with the decrease in the expression of mesenchymal and hematopoietic surface markers, such as CD44, CD45, CD90, and CD29. We detected strong correlation between the age of BMSC donor and ALP activity in BMSC culture induced with low doses of dexamethasone and vitamin C. Cells from 2- and 6-week-old donor SD rats exhibited markedly increased ALP activity that coincided with increased bone content and strong positive staining of mineralized nodules. In contrast, BMSCs isolated from 10-month-old donors showed the lowest ALP activity, and decreased bone content and mineralized nodules formation. Our results demonstrate that the increase in donor age negatively affects proliferation and differentiation capacity of BMSCs in culture.

A generalizability analysis of score consistency for the Balanced Inventory of Desirable Responding.

Our goal in this investigation was to evaluate the reliability of scores from the Balanced Inventory of Desirable Responding (BIDR) more comprehensively than in prior research using a generalizability-theory framework based on both dichotomous and polytomous scoring of items. Generalizability coefficients accounting for specific-factor, transient, and random-response error ranged from .64 to .75 for the BIDR's Self-Deception Enhancement (SDE) and Impression Management (IM) subscale scores, and these values were systematically lower than corresponding alpha (.66 to .83) and 1-week test-retest (.78 to .86) coefficients. Polytomous scoring provided higher reliability than dichotomous scoring on nearly all indexes reported. Random-response (8%-17%) and specific factor error (11%-17%) exceeded transient error (3%-6%) for both subscales and scoring methods. Doubling the number of items on a single occasion provided greater improvements in generalizability (.76-.83) than aggregating scores across 2 administrations (.72-.81). Both scoring methods provided reasonably high indexes of consistency (φ coefficients≥.91) at cut scores on the IM scale for detecting faked responses when all sources of error were taken into account. Implications of these results for common uses of the BIDR are discussed.