[Management strategy of femoral artery pseudoaneurysm combined with infectious wounds].

Objective: To investigate the surgical treatment methods of femoral artery pseudoaneurysm combined with infectious wounds and to evaluate the clinical effects. Methods: The retrospective observational research method was used. Twelve patients with femoral artery pseudoaneurysm combined with infectious wounds who met the inclusion criteria were admitted to Nanjing University of Chinese Medicine Wuxi Integrated Traditional Chinese and Western Medicine Hospital (Affiliated Hospital of Jiangnan University) from October 2014 to September 2022, including 6 males and 6 females, aged from 46 to 78 years. In the primary operation, debridement, tumor resection, and artery suture/venous grafting to repair the artery/artery ligation were performed, and the wound area after tumor resection ranged from 4.0 cm×1.5 cm to 12.0 cm×6.5 cm. Wounds that could be sutured were treated with tension reduction suture and extracutaneous continuous vacuum sealing drainage (VSD), while large wounds that could not be sutured were treated with VSD to control infection. In the secondary operation, tension reduction suture was performed to repair the wounds that could be sutured; large wounds were repaired with adjacent translocated flaps with area of 9.0 cm×5.0 cm to 15.0 cm×7.0 cm. Additionally, when the length of the exposed femoral artery was equal to or over 3.0 cm, the wounds were repaired with additional rectus femoris muscle flap with length of 15.0 to 18.0 cm. The donor areas of the flaps were directly sutured. The wound with artery ligation was treated with stamp skin grafting and continuous VSD. The bacterial culture results of the wound exudate samples on admission were recorded. The intraoperative blood loss, the location of femoral artery rupture, the artery treatment method, and the wound repair method in the primary operation were recorded, and the durations of catheter lavage, catheter drainage, and VSD treatment, and the drainage volume after the operation were recorded. The repair method of wounds in the secondary operation, the durations of catheter drainage and VSD treatment, and the total drainage volume after the operation were recorded. The survivals of flap/muscle flap/stamp skin grafts were observed, and the wound healing time was recorded. Follow-up after discharge was performed to evaluate the quality of wound healing and the walking function and to check whether the pulsatile mass disappeared. B-ultrasound or computed tomography angiography (CTA) was performed again to observe potential pseudoaneurysm recurrence and evaluate the patency of blood flow of the femoral artery. Results: The bacterial culture results of wound exudate samples of all the patients were positive on admission. The blood loss was 150 to 750 mL in the primary operation. The arterial ruptures were located in the femoral artery in 8 cases, in the external iliac artery in 2 cases, and in the femoral arteriovenous fistula in 2 cases. Six cases received direct artery suture, 4 cases received autologous great saphenous vein grafting to repair the artery, 1 case received autologous great saphenous vein bypass surgery, and 1 case received artery ligation. The primary wound suture was performed in 4 cases, along with catheter lavage for 3 to 5 days, catheter drainage for 4 to 6 days, VSD treatment for 5 to 7 days, and a total drainage volume of 80 to 450 mL after the surgery. In the secondary operation, the wounds were sutured directly in 3 cases along with catheter drainage for 2 to 3 days, the wound was repaired with scalp stamp skin graft and VSD treatment for 5 days in 1 case, the wounds were repaired with adjacent translocated flaps in 2 cases with catheter drainage for 2 to 3 days, and the wounds were repaired with rectus femoris muscle flaps+adjacent translocated flaps in 2 cases with catheter drainage for 3 to 5 days . The total drainage volume after the secondary operation ranged from 150 to 400 mL. All the skin flaps/muscle flaps/skin grafts survived after operation. The wound healing time ranged from 15 to 36 days after the primary operation. Follow-up of 2 to 8 months after discharge showed that the wounds of all patients healed well. One patient who underwent femoral artery ligation had calf amputation due to foot ischemic necrosis, and the rest of the patients regained normal walking ability. The pulsatile mass disappeared in inguinal region of all patients. B-ultrasound or CTA re-examination in 6 patients showed that the blood flow of femoral artery had good patency, and there was no pseudoaneurysm recurrence. Conclusions: Early debridement, tumor resection, and individualized artery treatment should be performed in patients with femoral artery pseudoaneurysm combined with infected wounds. Besides, proper drainage and personalized repair strategy should be conducted according to the wound condition to achieve a good outcome.

[Advances in the diagnosis and treatment strategy of polymyxin resistant Klebsiella pneumoniae].

In recent years, the detection rate of multidrug-resistant and pandrug-resistant Klebsiella pneumoniae has increased year on year, so polymyxin has received increasing attention as an antibiotic that is still sensitive to most of the multidrug-resistant strains. However, widespread use of polymyxin is likely to lead to the emergence of polymyxin-resistant Klebsiella pneumoniae. At the same time, the polymyxin hetero-resistance has made clinical prevention and treatment difficult. In addition to relying on the combination of polymyxins with other antibiotics, the search for new antibacterial drugs has also become a research hotspot. Research into early detection methods for polymyxin resistance can also help to optimize and improve the diagnosis and treatment strategies. This article reviewed the epidemic status, mechanism, detection methods and prevention measures of polymyxin-resistant Klebsiella pneumoniae.

[The effect of maternal HBV DNA levels on HBV intrauterine transmission and fetal distress].

Aim: To identify the key risk factors of intrauterine hepatitis B virus transmission (HBV) and its effect on the placenta and fetus. Methods: 425 infants born to hepatitis B surface antigen (HBsAg)-positive pregnant women who received combined immunization with hepatitis B immunoglobulin and hepatitis B vaccine between 2009 to 2015 were prospectively enrolled in this study. The intrauterine transmission situation was assessed by dynamic monitoring of infants HBV DNA load and quantitative HBsAg. Univariate and multivariate regression analysis was used to determine the high risk factors for intrauterine transmission. Stratified analysis was used to determine the relationship between maternal HBV DNA load and fetal distress. Transmission electron microscopy was used to observe HBV Effects on placental tissue. Results: HBV intrauterine infection rate was 2.6% (11/425). Multivariate analysis result showed that the maternal HBV DNA load was an independent risk factor for intrauterine infection among infants (P=0.011). Intrauterine infection and distress rate was significantly higher in infants with with maternal HBV DNA>106 IU/ml than those with HBV DNA <106 IU/ml (12.2% vs. 1.8%; χ2=11.275, P=0.006), and (24.4% vs. 16.0%, χ2=3.993, P=0.046). Transmission electron microscopy showed that mitochondrial edema, endoplasmic reticulum expansion and thicker basement membrane were apparent when the maternal HBV DNA>106 IU/ml than that of maternal HBV DNA<106 IU/ml (960 nm vs. 214 nm, Z=-2.782, P=0.005) in the placental tissue. Conclusion: Maternal HBV DNA>106 IU/ml is associated not only with intrauterine infection, but also with increased incidence of intrauterine distress and placental sub-microstructural changes, providing strong clinical and histological evidence for pregnancy avoidance and treatment in this population.

[Clinical efficacy and influencing factors of different modes of continuous negative pressure wound therapy on venous ulcer wounds of lower limbs].

Objective: To explore the clinical efficacy of different modes of continuous negative pressure wound therapy (NPWT) on venous ulcer wounds of lower limbs, and to analyze the influencing factors. Methods: From January 2018 to December 2019, 53 patients with venous ulcer of lower limbs who met the inclusion criteria and hospitalized in the Affiliated Hospital of Jiangnan University were recruited in this prospective randomized controlled study. According to the random number table, the patients were divided into single negative pressure therapy (SNPT) group (19 patients, 11 males and 8 females), cyclic alternating negative pressure therapy (CANPT) group (17 patients, 12 males and 5 females), and routine dressing change (RDC) group (17 patients, 10 males and 7 females), aged (47±11), (49±10), and (47±10) years respectively. After admission, patients in SNPT group were given continuous NPWT with the single negative pressure setting at -13.3 kPa, patients in CANPT group were also given continuous NPWT but with the cyclic alternating negative pressure setting from -16.0 to -10.7 kPa, while patients in RDC group were given dressing change with vaseline gauze soaked with iodophor. The wound healing rate was calculated on treatment day 7 and 14. Transcutaneous oxygen pressure (TcPO(2)) around the wound was detected by TcPO(2) meter before treatment and on treatment day 7 and 14. The wound exudate/drainage fluid was collected on treatment day 1, 4, 7, 10, and 14, with the pH value measured using a pH meter, and the volume of exudate/drainage fluid recorded. Before treatment and on treatment day 7 and 14, venous blood was collected to detect the serum levels of interleukin 1ß (IL-1ß), IL-6, tumor necrosis factor α(TNF-α), transforming growth factor-ß(1) (TGF-ß(1)), vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF). Before treatment and on treatment day 7 and 14, wound exudates were collected for bacterial culture, and Visual Analogue Scale and Hamilton Anxiety Scale were used to evaluate the degree of wound pain and anxiety of patients respectively. The length of hospital stay and the total treatment cost were counted. Analysis of variance for repeated measurement, one-way analysis of variance, least significant difference test, Kruskal Wallis H test, Mann Whitney U test, chi-square test, Fisher's exact probability method test, and Bonferroni correction were used to analyze the data. According to the wound healing rate on treatment day 14, the efficiency of patients were divided into two grades of significant healing with wound healing rate≥70% and non significant healing with wound healing rate<70%. According to the two categories of wound healing rate as dependent variables, the levels of TcPO(2), IL-1ß, IL-6, TNF-α, TGF-ß(1), VEGF, bFGF levels and bacterial detection, wound pain and anxiety before treatment, wound exudate/drainage fluid volume and pH value on treatment day 1 were taken as covariates, and binary classification multifactor logistic regression analysis was used to analyze the risk factors of significant wound healing. Results: (1) On treatment day 7, the wound healing rate of patients in SNPT group was (33±10) %, which was significantly higher than (24±9) % of RDC group (P<0.05). On treatment day 14, the wound healing rates of patients in SNPT group and CANPT group were (71±15)% and (66±18)%, respectively, which were significantly higher than (45±19)% of RDC group (P<0.01). (2) Compared with those of RDC group, the TcPO(2) value around the wound of patients was significantly increased in SNPT group on treatment day 14 and in CANPT group on treatment day 7 and 14 (P<0.05 or P<0.01), the pH value of wound drainage fluid of patients was significantly decreased in SNPT group on treatment day 10 and 14 and in CANPT group on treatment day 7 and 14 (P<0.05), the volume of wound drainage fluid of patients was significantly reduced in SNPT group on treatment day 10 and 14 and in CANPT group on treatment day 7, 10, and 14 (Z=-4.060, -4.954, -2.413, -4.085, -4.756, P<0.05 or P<0.01), the serum levels of IL-1ß, IL-6, and TNF-α of patients were significantly decreased in SNPT group and CANPT group on treatment day 7 and 14 (P<0.01), the serum level of TGF-ß(1) of patients was significantly increased in CANPT group on treatment day 14 (P<0.05), the serum levels of VEGF and bFGF were significantly increased in SNPT group and CANPT group on treatment day 14 (P<0.01), the bacteria detection proportion of wound exudate, wound pain, and anxiety scores of patients were significantly decreased in SNPT group and CANPT group on treatment day 7 and 14 (P<0.01). Compared between the negative pressure therapy two groups, except the wound pain score of patients in CANPT group was significantly lower than that in SNPT group (P<0.01) on treatment day 7, the other indicators mentioned above were similar. (3) The length of hospital stay of patients in SNPT group was similar to that in CANPT group (P>0.05), which were significantly shorter than the time in RDC group (P<0.01). The total treatment cost of patients among the three groups was similar (F=1.766, P>0.05). (4) Before treatment, the serum levels of TNF-α and bFGF, TcPO(2) around the wound, and the degree of wound pain were risk factors for significant wound healing (odds ratio=1.109, 0.950, 1.140, 2.169, 95% confidence interval=1.012-1.217, 0.912-0.988, 1.008-1.290, 1.288-3.651, P<0.05 or P<0.01). Conclusions: Clinical application of continuous NPWT under single negative pressure mode and cyclic alternating negative pressure mode has a positive effect on improving the wound base and healing rate of venous ulcer of lower limbs. But cyclic alternating negative pressure mode is significantly more effective than single negative pressure mode in improving TcPO(2) around the wound, reducing wound pH value, reducing exudate volume and relieving pain. The serum levels of TNF-α and bFGF, TcPO(2) around the wound and the degree of wound pain were the risk factors that affect the wound healing significantly.

Bradykinin alleviates DR retinal endothelial injury by regulating HMGB-1/NF-κB pathway.

OBJECTIVE: Diabetic retinopathy (DR) is one of the most important complications of diabetes (DM) and the leading cause of blindness in adults. Bradykinin (BK) is involved in several pathophysiological processes, such as inflammation, pain, cell proliferation, and tumors. It plays a crucial role in corneal epithelial cells, corneal stromal cells, and fibroblasts. However, the role of BK in DR retinal endothelial injury remains unclear. PATIENTS AND METHODS: Human retinal microvascular endothelial cells (hRECs) were cultured in vitro and randomly divided into 3 groups, control group in which hRECs were cultured in normal glucose concentration, high glucose group in which hRECs were cultured in the presence of high glucose, and BK group in which hRECs were cultured in the presence of high glucose with 1 µM BK. The MTT assay (3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide) was used to detect cell proliferation. Caspase-3 activity was adopted to detect Caspase-3 activity in hRECs. The colorimetric method was selected to determine lactate dehydrogenase (LDH) activity, superoxide dismutase (SOD) activity, and ROS content. Western blot was used to test HMGB-1/NF-κB and vascular endothelial growth factor (VEGF) expression changes. Enzyme-linked immunosorbent assay (ELISA) was performed to detect the secretion of inflammatory factor tumor necrosis factor-α (TNF-α) and interleukin-1ß (IL-1ß). RESULTS: In the presence of high glucose, hRECs cells proliferation was significantly reduced, Caspase-3 activity was enhanced, LDH and ROS levels were increased, SOD activity was declined with increased expression of HMGB-1, NF-κB, VEGF, as well as secretion of TNF-α and IL-1ß compared with control group (p < 0.05). BK significantly inhibited the proliferation of hRECs cells, enhanced Caspase-3 activity, decreased the content of LDH and ROS, increased SOD activity, reduced the expressions of HMGB-1 and NF-κB protein, attenuated the expression of VEGF, and restrained the secretion of TNF-α and IL-1ß compared with high glucose group (p < 0.05). CONCLUSIONS: BK can inhibit the growth and proliferation of retinal endothelial cells by regulating HMGB-1/NF-κB signaling pathway, attenuating oxidative stress and inflammation, thereby delaying DR development and progress.

[Repair of pressure ulcers in ischial tuberosity of 15 patients by partially de-epithelialized posterior femoral bilobed flaps].

Fifteen patients with sinus-type pressure ulcer in ischial tuberosity were admitted to our unit from April 2013 to April 2017, including 12 patients of unilateral pressure ulcer and 3 patients of bilateral pressure ulcer. The wounds were with infection of different degrees. The outer wound area of pressure ulcer before debridement ranged from 1.5 cm×1.0 cm to 6.0 cm×5.0 cm. Fifteen patients with 15 pressure ulcers were treated with vacuum sealing drainage for 3 to 13 days after debridement and sinus wall resection. Unilateral pressure ulcer was repaired with posterior femoral bilobed flap. One side of bilateral pressure ulcer was repaired with posterior femoral bilobed flap, and the other side was repaired with gluteus maximus muscle flap combined with local flap. The size of flaps ranged from 11.0 cm×7.5 cm to 15.0 cm×10.0 cm. Epidermis of the distal part and edge of the main flap was removed to make complex dermal tissue flap to fill the deep cavity. The other part of the main flap was applied to cover wound, and another flap of the bilobed flap was applied to cover the donor site where main flap was resected. The donor sites were sutured directly. The posterior femoral bilobed flaps in 15 patients survived after operation. Pressure ulcers of 12 patients were healed well. Incision of 2 patients ruptured and healed 15 days after second sewing. One pressure ulcer with infection under the flap healed on 16 days post second completely debridement. During follow-up of 3 to 18 months, flaps were with soft texture, good appearance, and no recurrence.

[Effects of application of citrate anticoagulation in bedside continuous blood purification of severe burn patients with sepsis].

Objective: To investigate the effects of application of citrate anticoagulation in bedside continuous blood purification (CBP) of severe burn patients with sepsis, so as to provide reference for choosing anticoagulants in CBP of these patients. Methods: Thirty severe burn patients with sepsis, conforming to the study criteria, were admitted to our burn intensive care unit from January 2014 to July 2017. Patients were divided into heparin group and citrate group according to computer randomization method, with 15 cases in each group. Patients in two groups all received bedside CBP treatment. Patients in heparin group used local heparin anticoagulation, while patients in citrate group used local citrate anticoagulation. Time of predicted single-time CBP treatment, time of single-time CBP treatment, time of accumulative CBP treatment, and rate of reaching the standard of CBP treatment time were counted. Changes of prothrombin time (PT), activated partial thromboplastin time (APTT), international normalized ratio (INR), fibrinogen, serum procalcitonin, and C-reactive protein (CRP) of patients before and after treatment were monitored. Hemorrhage in wounds, incision on trachea, and arteriovenous intubation point, and other complications during and after CBP treatment were observed. Data were processed with independent sample t test and chi-square test. Results: (1) Time of predicted single-time CBP treatment of patients in the two groups was equal. Time of single-time CBP treatment and time of accumulative CBP treatment of patients in citrate group were longer than those in heparin group. Rate of reaching the standard of CBP treatment time of patients in citrate group was significantly higher than that in heparin group (χ(2)=16.655, P<0.01). (2) There was no statistically significant difference in PT, APTT, INR, fibrinogen, serum procalcitonin, and CRP of patients in the two groups before CBP treatment (t=0.203, -1.006, 0.203, 0.039, -1.591, -0.824, P>0.05). PT and APTT of patients in citrate group after CBP treatment were (14.2±1.6) and (45±7) s, respectively, significantly shorter than (15.5±1.4) and (53±6) s in heparin group (t=2.395, 3.321, P<0.05 or P<0.01). INR of patients in citrate group after CBP treatment was 1.13±0.12, significantly lower than 1.24±0.12 in heparin group (t=2.395, P<0.05). Fibrinogen of patients in citrate group after CBP treatment was (3.5±0.6) g/L, significantly higher than (3.0±0.6) g/L in heparin group (t=-2.427, P<0.05). Serum procalcitonin and CRP of patients in citrate group after CBP treatment were significantly lower than those in heparin group (t=2.520, 2.710, P<0.05). Decreased degree of serum procalcitonin and CRP of patients in citrate group after CBP treatment were (1.8±0.6) ng/mL and (143±69) mg/L, respectively, significantly higher than (0.9±0.6) ng/mL and (95±50) mg/L in heparin group (t=-4.033, -2.170, P<0.05 or P<0.01). (3) During CBP treatment, patients in heparin group experienced 21 times of exacerbation of wound hemorrhage and 10 times of new hemorrhage, including 2 times of hemorrhage at incision on trachea and 8 times of hemorrhage at arteriovenous intubation point. No exacerbation of hemorrhage or new hemorrhage happened in patients of citrate group. After CBP treatment, no electrolyte disturbance happened in patients of heparin group, but 1 patient in citrate group experienced hypocalcemia. Conclusions: Application of citrate anticoagulation in bedside CBP of severe burn patients with sepsis shows light impact on systematic coagulation status, and can effectively decrease inflammation reaction of burn sepsis with low rate of hemorrhage.

Characterization and effects of miR-21 expression in esophageal cancer.

The aim of this study was to investigate the expression of miR-21 in esophageal cancer and the impact of miR-21 on apoptosis, invasion, and the expression of target genes in esophageal cancer cells. Fluorescence quantitative polymerase chain reaction analysis was used to detect the expression of miR-21 in human esophageal tissues, adjacent tissues, and an esophageal cancer cell line (TE-13). The antisense miR-21 oligonucleotide was generated commercially using the solid-phase chemical synthesis method. Transient transfection was used to transfect esophageal cancer cells (TE-13 antisense and TE-13 control cells). Flow cytometry and Transwell cell assays were used to detect the apoptosis and invasion of esophageal cancer cells, respectively. The western blot method was used to detect the expression of PTEN, PDCD4, and K-ras proteins. These analyses determined that mir-21 expression significantly increased in esophageal cancer tissues and in TE-13 cells, and that this phenomenon was not associated with staging or lymph node metastasis. The apoptosis rate of TE-13 control cells was lower than that of antisense TE-13 cells indicating an enhanced invasive ability. In tissues adjacent to esophageal cancer and in TE-13 antisense cells, the expression of PTEN and PDCD4 was found to be higher than that in the control group, whereas the expression of K-ras showed the opposite pattern. Together, these results suggest that miR- 21 might be involved in the development and metastasis of esophageal cancer, through interaction with its PDCD4 and K-ras target genes.

Association of miR-21 with esophageal cancer prognosis: a meta-analysis.

The present study aimed to explore the relationship between miRNA expression and survival in patients with esophageal cancer (EC) using meta-analysis. We searched PubMed, EMBASE, CNKI, Wanfang, and ISI Web of Science databases without time restrictions, and extracted relevant data, such as the name of first author, publication year, age, gender, number of case, etc. from the studies included. We calculated the pooled hazard ratios (HRs) using the RevMan 5.2 software. A total of five studies involving 504 subjects were included in the meta-analysis, with the purpose of analyzing the association of miRNA-21 expression with EC prognosis. The pooled HR of elevated versus decreased miR-21 expression in EC was 1.87 [95% confidence interval (CI): 1.37-2.55, P < 0.001], with elevated miR-21 expression being associated with poorer prognosis for patients with EC. Our results support a prognostic role for miR-21 in EC.

COP-compost: a software to study the degradation of organic pollutants in composts.

Composting has been demonstrated to be effective in degrading organic pollutants (OP) whose behaviour depends on the composting conditions, the microbial populations activated and interactions with organic matters. The fate of OP during composting involves complex mechanisms and models can be helpful tools for educational and scientific purposes, as well as for industrialists who want to optimise the composting process for OP elimination. A COP-Compost model, which couples an organic carbon (OC) module and an organic pollutant (OP) module and which simulates the changes of organic matter, organic pollutants and the microbial activities during the composting process, has been proposed and calibrated for a first set of OP in a previous study. The objectives of the present work were (1) to introduce the COP-Compost model from its convenient interface to a potential panel of users, (2) to show the variety of OP that could be simulated, including the possibility of choosing between degradation through co-metabolism or specific metabolism and (3) to show the effect of the initial characteristics of organic matter quality and its microbial biomass on the simulated results of the OP dynamic. In the model, we assumed that the pollutants can be adsorbed on organic matter according to the biochemical quality of the OC and that the microorganisms can degrade the pollutants at the same time as they degrade OC (by co-metabolism). A composting experiment describing two different (14)C-labelled organic pollutants, simazine and pyrene, were chosen from the literature because the four OP fractions simulated in the model were measured during the study (the mineralised, soluble, sorbed and non-extractable fractions). Except for the mineralised fraction of simazine, a good agreement was achieved between the simulated and experimental results describing the evolution of the different organic fractions. For simazine, a specific biomass had to be added. To assess the relative importance of organic matter dynamics on the organic pollutants' behaviour, a sensitivity analysis was conducted. The sensitivity analysis demonstrated that the parameters associated with organic matter dynamics and its initial microbial biomass greatly influenced the evolution of all the OP fractions, although the initial biochemical quality of the OC did not have a significant impact on the OP evolution.

Accuracy of ß-D-glucan for the diagnosis of Pneumocystis jirovecii pneumonia: a meta-analysis.

Pneumocystis jirovecii pneumonia (PCP) can affect various types of immunocompromised patients. We sought to evaluate the diagnostic accuracy of (1→3)-ß-D-glucan (BDG) for the diagnosis of PCP. We carried out a meta-analysis of relevant studies, identified through PubMed and Scopus. Eligible studies were those that reported BDG diagnostic data in cases with documented PCP and controls with other conditions. Cases of invasive fungal infections and healthy controls were excluded. We performed a bivariate meta-analysis of sensitivity and specificity and constructed a hierarchical summary receiver operating characteristics (HSROC) curve. Fourteen studies were included in the meta-analysis. BDG data were analysed for 357 PCP cases and 1723 controls. The average (95% confidence interval) sensitivity and specificity of BDG were 94.8% (90.8-97.1%) and 86.3% (81.7-89.9%), respectively. The positive and negative likelihood ratios were 6.9 (5.1-9.3) and 0.06 (0.03-0.11), respectively. The area under the HSROC curve was 0.965 (0.945-0.978). Serum BDG shows excellent sensitivity and very good specificity in the diagnosis of PCP. Still, in clinical practice the test results should be interpreted in the context of the underlying clinical characteristics of the individual patient.

Impact of temperature, CO2 fixation and nitrate reduction on selenium reduction, by a paddy soil Clostridium strain.

AIMS: To elucidate the impact of CO(2) fixation, nitrate reduction and temperature on selenium reduction by a newly identified acetogenic bacterium, Clostridium sp. BXM. METHODS AND RESULTS: A series of culture experiments were designed to evaluate the impact of temperature, CO(2) fixation and nitrate reduction on the rate and extent of selenium reduction by strain BXM. The products of selenium reduction, CO(2) fixation and nitrate reduction were determined. Molecular analysis was performed to identify the functional genes involved in the selenium reduction process. CO(2) may have enhanced the activity of hydrogenase I and/or the level of cytochrome b, thus increasing selenium reduction. Nitrate may inhibit selenium reduction due to its higher reduction potential and/or by decreasing selenite/selenate reductase activity. The suitable temperature was 37 and 30 °C for selenite reduction under anaerobic and aerobic conditions, respectively. The optimum temperature was 30 °C for selenate reduction under both anaerobic and aerobic conditions. CO(2) fixation and nitrate reduction by Clostridium sp. BXM stimulated each other. CONCLUSIONS: Clostridium sp. BXM was capable of reducing up to 36-94% of 1 mmol l(-1) selenate and selenite under anaerobic or aerobic conditions over 15 days. The strain might be used for the precipitation of Se from highly selenium-contaminated water or sediments. SIGNIFICANCE AND IMPACT OF THE STUDY: The findings contribute to the current understanding about the role that micro-organisms play in the detoxification of toxic selenium compounds in paddy soils. Micro-organisms in paddy soils can influence selenium accumulation in rice grain and hence human selenium intake.

Utilization of urban sewage sludge: Chinese perspectives.

PURPOSE: Urbanization and industrialization in China has resulted in a dramatic increase in the volume of wastewater and sewage sludge produced from wastewater treatment plants. Problems associated with sewage sludge have attracted increasing attention from the public and urban planners. How to manage sludge in an economically and environmentally acceptable manner is one of the critical issues that modern societies are facing. METHODS: Sludge treatment systems consist of thickening, dewatering, and several different alternative main treatments (anaerobic digestion, aerobic digestion, drying, composting, and incineration). Agricultural application, landfill, and incineration are the principal disposal methods for sewage sludge in China. However, sewage sludge disposal in the future should focus on resource recovery, reducing environmental impacts and saving economic costs. RESULTS: The reuse of biosolids in all scenarios can be environmentally beneficial and cost-effective. Anaerobic digestion followed by land application is the preferable options due to low economic and energy costs and material reuse. CONCLUSION: It is necessary to formulate a standard suitable for the utilization of sewage sludge in China.

Modelling of organic matter dynamics during the composting process.

Composting urban organic wastes enables the recycling of their organic fraction in agriculture. The objective of this new composting model was to gain a clearer understanding of the dynamics of organic fractions during composting and to predict the final quality of composts. Organic matter was split into different compartments according to its degradability. The nature and size of these compartments were studied using a biochemical fractionation method. The evolution of each compartment and the microbial biomass were simulated, as was the total organic carbon loss corresponding to organic carbon mineralisation into CO(2). Twelve composting experiments from different feedstocks were used to calibrate and validate our model. We obtained a unique set of estimated parameters. Good agreement was achieved between the simulated and experimental results that described the evolution of different organic fractions, with the exception of some compost because of a poor simulation of the cellulosic and soluble pools. The degradation rate of the cellulosic fraction appeared to be highly variable and dependent on the origin of the feedstocks. The initial soluble fraction could contain some degradable and recalcitrant elements that are not easily accessible experimentally.

Environmental impacts on soil and groundwater at airports: origin, contaminants of concern and environmental risks.

Environmental impacts of airports are similar to those of many industries, though their operations expand over a very large area. Most international impact assessment studies and environmental management programmes have been giving less focus on the impacts to soil and groundwater than desirable. This may be the result of the large attention given to air and noise pollution, relegating other environmental descriptors to a second role, even when the first are comparatively less relevant. One reason that contributes to such "biased" evaluation is the lack of systematic information about impacts to soil and groundwater from airport activities, something the present study intends to help correct. Results presented here include the review of over seven hundred documents and online databases, with the objective of obtaining the following information to support environmental studies: (i) which operations are responsible for chemical releases?; (ii) where are these releases located?; (iii) which contaminants of concern are released?; (iv) what are the associated environmental risks? Results showed that the main impacts occur as a result of fuel storage, stormwater runoff and drainage systems, fuel hydrant systems, fuel transport and refuelling, atmospheric deposition, rescue and fire fighting training areas, winter operations, electrical substations, storage of chemical products by airport owners or tenants, and maintenance of green areas. A new method for ranking environmental risks of organic substances, based on chemical properties, is proposed and applied. Results show that the contaminants with the highest risks are the perfluorochemicals, benzene, trichloroethylene and CCl(4). The obtained information provides a basis for establishing the planning and checking phases of environmental management systems, and may also help in the best design of pollution prevention measures in order to avoid or reduce significant environmental impacts from airports.

Comparison of polycyclic aromatic hydrocarbon uptake pathways and risk assessment of vegetables from waste-water irrigated areas in northern China.

Atmospheric deposition is the dominant pathway for PAH uptake by vegetables grown in peri-urban areas. Different polycyclic aromatic hydrocarbon (PAH) uptake pathways and the associated health risk were investigated in vegetable samples collected from the Beijing-Tianjin city cluster, China, where irrigation with waste or reclaimed water has been practised for many decades. Sampling comprised 23 diverse sites and the roots and shoots of six types of vegetables. Among the different edible vegetable parts, the highest PAH concentrations were found in radish roots and the lowest in cauliflower heads. Bioconcentration factors (BCFs) for individual PAHs showed a weakly decreasing trend with increasing log K(OW). To investigate whether the air-leaf or soil-root-shoot uptake dominates, the measured values were compared with estimations from a generic one-compartment model. The results and related observations are more consistent with an atmospheric uptake pathway than a soil-uptake pathway. The PAH isomeric ratios are consistent with pyrogenic sources (from combustion of fossil fuel and biomass). A health risk assessment on the consumption of the edible parts of vegetables revealed that all studied vegetables, except for 16% of Chinese cabbage samples, are safe for consumption. The results of this study indicate the potential health risk of consuming vegetables from waste-water irrigated areas of this city cluster and provide new insights regarding the transfer of PAHs in vegetables grown in this region.

Speciation and distribution of arsenic and localization of nutrients in rice grains.

Arsenic (As) contamination of rice grains and the generally low concentration of micronutrients in rice have been recognized as a major concern for human health. Here, we investigated the speciation and localization of As and the distribution of (micro)nutrients in rice grains because these are key factors controlling bioavailability of nutrients and contaminants. Bulk total and speciation analyses using high-pressure liquid chromatography (HPLC)-inductively coupled plasma mass spectrometry (ICP-MS) and X-ray absorption near-edge spectroscopy (XANES) was complemented by spatially resolved microspectroscopic techniques (micro-XANES, micro-X-ray fluorescence (micro-XRF) and particle induced X-ray emission (PIXE)) to investigate both speciation and distribution of As and localization of nutrients in situ. The distribution of As and micronutrients varied between the various parts of the grains (husk, bran and endosperm) and was characterized by element-specific distribution patterns. The speciation of As in bran and endosperm was dominated by As(III)-thiol complexes. The results indicate that the translocation from the maternal to filial tissues may be a bottleneck for As accumulation in the grain. Strong similarities between the distribution of iron (Fe), manganese (Mn) and phosphorus (P) and between zinc (Zn) and sulphur (S) may be indicative of complexation mechanisms in rice grains.

Differential characteristics of the early stage of lung inflammation induced by SARS-CoV Nucleocapsid protein related to age in the mouse.

OBJECTIVE: Severe acute respiratory syndrome (SARS) is an acute infectious disease of the respiratory system which has newly emerged. Interestingly, it appears to be a disease that predominantly affects adults while the mortality in children is extremely low. However, the pathogenesis of SARS in relation to different characteristics relevant to age remains unclear. MATERIAL AND METHODS: To better understand the role of cytokines in the immunopathological processes of SARS, weanling (4 weeks old), young (6 weeks old) and adult (10 weeks old) male BALB/C mice were inoculated intranasally with N-protein of SARS-CoV in this study. Serum or lung homogenate levels of some cytokines such as tumor necrosis factor-alpha (TNF-alpha) and interferon-gamma (IFN-gamma) along with acute injury lung index and histology were also analyzed. RESULTS: Histopathological analysis of adult male BALB/C mice after N-protein infection showed progressive inflammatory reactions, especially pulmonary edema, in accordance with a moderately (approximately 13%) elevated level of W/D ratio at 24 h. Although adult groups underwent a progressive lung inflammation in the acute phase accompanied by raised levels of TNF-alpha in serum, no significant changes in lung TNF-alpha level were reported simultaneously. Moreover, adult SARS infected BALB/c mice showed elevated levels of IFN-gamma while IFN-gamma levels in weanling and young groups had no obvious association with lung inflammation. CONCLUSION: Our study supports the observation that adult mice do have progressively greater immune reactions than weanling and adolescent ones over time. The relative immaturity of the immune system in weanlings may confer benefit leading to less impairment of lung function. However, the measurement of TNF-alpha and IFN-gamma levels was not indicative of the severity of lung injury at the early stage of disease.

High percentage inorganic arsenic content of mining impacted and nonimpacted Chinese rice.

Two approaches were undertaken to characterize the arsenic (As) content of Chinese rice. First, a national market basket survey (n = 240) was conducted in provincial capitals, sourcing grain from China's premier rice production areas. Second, to reflect rural diets, paddy rice (n = 195) directly from farmers fields were collected from three regions in Hunan, a key rice producing province located in southern China. Two of the sites were within mining and smeltery districts, and the third was devoid of large-scale metal processing industries. Arsenic levels were determined in all the samples while a subset (n = 33) were characterized for As species, using a new simple and rapid extraction method suitable for use with Hamilton PRP-X100 anion exchange columns and HPLC-ICP-MS. The vast majority (85%) of the market rice grains possessed total As levels < 150 ng g(-1). The rice collected from mine-impacted regions, however, were found to be highly enriched in As, reaching concentrations of up to 624 ng g(-1). Inorganic As (As(i)) was the predominant species detected in all of the speciated grain, with As(i) levels in some samples exceeding 300 ng g(-1). The As(i) concentration in polished and unpolished Chinese rice was successfully predicted from total As levels. The mean baseline concentrations for As(i) in Chinese market rice based on this survey were estimated to be 96 ng g(-1) while levels in mine-impacted areas were higher with ca. 50% of the rice in one region predicted to fail the national standard.