Effects of cadmium (Cd) on microbial biomass, activity and community diversity were assessed in a representative variable charge soil (Typic Aquult) using an incubation study. Cadmium was added as Cd(NO3)(2) to reach a concentration range of 0-16 mg Cd/kg soil. Soil extractable Cd generally increased with Cd loading rate, but decreased with incubation time. Soil microbial biomass was enhanced at low Cd levels (0.5-1 mg/kg), but was inhibited consistently with increasing Cd rate. The ratio of microbial biomass C/N varied with Cd treatment levels, decreasing at low Cd rate (<0.7 mg/kg available Cd), but increasing progressively with Cd loading. Soil respiration was restrained at low Cd loading (<1 mg/kg), and enhanced at higher Cd levels. Soil microbial metabolic quotient (MMQ) was generally greater at high Cd loading (1-16 mg/kg). However, the MMQ is also affected by other factors. Cd contamination reduces species diversity of soil microbial communities and their ability to metabolize different C substrates. Soils with higher levels of Cd contamination showed decreases in indicator phospholipids fatty acids (PLFAs) for Gram-negative bacteria and actinomycetes, while the indicator PLFAs for Gram-positive bacteria and fungi increased with increasing levels of Cd contamination.
Biomass ; Cadmium ; pharmacology ; Carbon ; metabolism ; Fatty Acids ; metabolism ; Microbial Viability ; drug effects ; Nitrogen ; metabolism ; Phospholipids ; metabolism ; Soil Microbiology ; Time Factors

Helicobacter pylori (H.pylori) infection is a recognized risk factor of dementia,while its role and mechanism in Alzheimer disease (AD) remained unclarified.Our previous study has identified that injection of soluble H.pylori filtrate could induce AD-like pathologic changes and cognitive impairment in SD rats.In the present study,we further explored the effect of long-term stomach colonization of H.pylori bacteria on the brains of SD rats.The results showed that H.pylori bacteria gavage induced an efficient colonization of H.pylori in the stomach after four weeks.However,there was no significant change of tau phosphorylation at Thr205 (pT205),Thr231 (pT231),Ser396 (pS396) and Ser404 (pS404) sites in the hippocampus and cerebral cortex.The H.pylori-infected rats also showed no cognitive impairment.These observations may result from inefficient release of bacterial pathogenic factors or the overall lack of host inflammatory responses.We conclude that SD rat with long-term H.pylori colonization in the stomach is not a suitable animal model for exploring the effects of H.pylori infection on brain function in human beings;administration of bacterial filtrates may better reveal the systemic pathologic changes induced by bacterial infection in animals which show a negative host response to bacterial colonization.

Objective: To investigate the value of tumor perfusion parameter measured by using double contrast-enhanced ultrasound (DCEUS) QontraXt three-dimensional pseudocolor quantitative analysis to the therapeutic effect evaluation of preoperative neoadjuvant chemotherapy (NAC) in advanced gastric cancer (AGC) patients. Methods: Eighty-nine AGC patients underwent 3 cycles of preoperative NAC (XELOX) followed by complete resection of lesion. The DCEUS QontraXt three-dimensional pseudocolor was performed one or two weeks before the NAC and operation were applied, respectively. The peak enhancement (PE), time to peak (TP), sharpness of the bolus (β) and area under the enhancement curve (AUC) of primary gastric tumor were measured by QontraXt three-dimensional pseudocolor quantitative analysis. These DCEUS parameters between respond and non-respond groups before and after NAC therapy were compared. The prediction accuracy of DCEUS to the therapeutic effect evaluation of preoperative NAC was determined by the receive operating characteristic (ROC) curves. Results: Among 89 AGC patients, 52 patients responded to NAC therapy, while 37 patients resisted to NAC therapy. Twelve cases in respond group and 26 cases in non-respond group were mucinous carcinoma. Forty cases in respond group and 11 cases in non-respond group were non-mucinous carcinoma (P<0.05). In responder group, the PE and TP before NAC were (53.7±9.3)% and (14 521±2 667) ms, and (32.2±5.5)% and (17 235±1 898) ms after NAC. The ratio of changes of PE (ΔPE) and TP (ΔTP) were 0.43±0.17 and 0.36±0.14, respectively. In non-respond group, the PE and TP before NAC were (54.4±7.2)% and (13 869±3 247) ms, and (45.3±6.1)% and (15 127±1 423) ms after NAC therapy. The ratio of ΔPE and ΔTP were 0.24±0.20 and 0.22±0.12. The PE and TP after NAC, the ratio of ΔPE and ΔTP were significant different among these two groups (all of P<0.05). The ROC curves showed that the ratio of ΔPE in assessing the respond of gastric cancer patients to NAC was superior compared to other parameters (AUC=0.784, P=0.004). The optimal cut-off value of the ratio of ΔPE was 24% and its sensitivity and specificity to the therapeutic effect evaluation of NAC in gastric cancer were 82.7% and 64.9%. Conclusion DCEUS QontraXt three-dimensional pseudocolor quantitative analysis might be a novel, noninvasive and reliable method to evaluate the therapeutic effect of preoperative NAC in AGC patients.