[Sorption of Phenanthrene to Soybean and Wheat Roots and the Bioavailability of Sorbed Phenanthrene].

The study of PAHs sorption and bioavailability to different crop roots could help to reveal the environmental behavior of PAHs in the ecosystem and evaluate the ecological risk of PAHs. However, there is little information about the differences in PAHs sorption to different roots and the bioavailability of the sorbed PAHs. In this paper, the experiments were conducted on the sorption/desorption of phenanthrene to soybean and wheat roots under different sorption times and different phenanthrene concentrations. The results showed that the trend of phenanthrene sorption in vivo was first increased and then decreased and finally reached a balance, which was related to the transport delay in vivo; the trend in dead and dried roots was first increased and then reached a balance. The greater specific surface area and the higher fat content, the faster the balance was. Freundlich isotherm was fitted better than Henry isotherm for dead and dried roots, Langmuir isotherm was best fitted in wheat roots. All of the fitted isotherms indicated that the distribution and the surface adsorption could control the phenanthrene sorption. Because of the special binding between living roots and phenanthrene, the fit effect was poor. The phenanthrene sorption capacity of soybean roots was higher than that of wheat, which was related to the high water content, fat content and membrane permeability. The phenanthrene sorbed on the roots was hard to desorb, and the desorption trends were wheat roots> soybean roots; living roots> dried roots> dead roots. The bioavailability of root-sorbed phenanthrene was consistent with the desorption results. Our results could provide data for the assessment of environmental risks of PAHs sorbed onto crop roots.

[Extraction of plant root apoplast solution: a case study with polycyclic aromatic hydrocarbons].

It is of great importance to investigate the extraction of polycyclic aromatic hydrocarbons (PAHs) in plant root apoplast solution for elucidating the mechanisms underlying root absorption and translocation of PAHs and their control. However, little information is available on the extraction of plant root apoplast solution to date. In this study, wheat was employed and phenanthrene was used as the representative of PAHs. Phenanthrene extracted from wheat root apoplast solution increased with increasing vaccum degree, vacuum time, centrifugal speed and centrifugal time. Glucose- 6-phosphate dehydrogenase (G6PGH) activity in wheat root apoplast solution was enhanced with increasing vacuum degree, vacuum time, centrifugal speed and centrifugal time. For the vacuum infiltration centrifugation extraction, the optimal vacuum degree was 70 kPa, the optimal vacuum time was 10 min, the optimal centrifugal speed was 3 068 r x min(-1), and the optimal centrifugal time was 15 min. Our results provide a more convenient and effective method for investigation on pollutant transport in plant root apoplast.

Scavenging of BHCs and DDTs from soil by thermal desorption and solvent washing.

Intensive remediation of abandoned former organochlorine pesticides (OCPs) manufacturing areas is necessary because the central and surrounding soils contaminated by OCPs are harmful to crop production and food safety. Organochlorine and its residues are persistent in environments and difficult to remove from contaminated soils due to their low solubility and higher sorption to the soils. We performed a comprehensive study on the remediation of OCPs-contaminated soils using thermal desorption technique and solvent washing approaches. The tested soil was thermally treated at 225, 325, 400, and 500 °C for 10, 20, 30, 45, 60, and 90 min, respectively. In addition, we tested soil washing with several organic solvents including n-alcohols and surfactants. The optimal ratio of soil/solvent was tested, and the recycling of used ethanol was investigated. Finally, activities of polyphenol oxidase (PPO), urease (URE), alkaline phosphatase, acid phosphatase (ACP), and invertase (INV) were assayed in the treated soils. The tested soil was thermally treated at 500 °C for 30 min, and the concentration of contaminants in soil was decreased from 3,115.77 to 0.33 mg kg(-1). The thermal desorption in soil was governed by the first-order kinetics model. For the chemical washing experiment, ethanol showed a higher efficiency than any other solvent. Using a 1:20 ratio of soil/solvent, the maximum removal of OCPs was achieved within 15 min. Under this condition, approximately 87 % of OCPs was removed from the soils. More than 90 % of ethanol in the spent wash fluid could be recovered. Activities of some enzymes in soils were increased after ethanol treatment. But ALP, ACP, and INV activities were decreased and PPO and URE showed slightly higher activities following remediation by thermal treatment. Both heating temperature and time were the key factors for thermal desorption of OCPs. The n-alcohol solvent showed higher removal of OCPs from soils than surfactants. The highly efficient removal of OCPs from soil was achieved using ethanol. More than 90 % of ethanol could be recovered and be reused following distillation. This study provides a cost-effective and highly efficient way to remediate the OCPs-contaminated soils.

[Characterization comparison of polycyclic aromatic hydrocarbon uptake by roots of different crops].

It is important to investigate the differences in polycyclic aromatic hydrocarbon (PAH) uptake by roots of different crops for selecting and breeding less or excess uptake species of PAHs by genetic engineering, and further yielding safe production and phytoremediating the soil or water contaminated with PAHs. Hydroponic experiments were performed to study characterization comparison of phenanthrene (a representative of PAHs) uptake by soybean, wheat and carrot roots. Soybean, carrot and wheat roots can take up phenanthrene from Hoagland nutrient solution and the phenanthrene absorbed by roots increases with incubation time. The uptake process consists of two sequential phases: a fast accumulation process followed by a slow one. The capability to take up phenanthrene for the three crops can be arranged as soybean > carrot > wheat. The relationship between the phenanthrene absorbed and time fits Elovich equation well. Uptake rate constants for soybean, carrot and wheat roots are 4.31, 4.10 and 2.84 mg x (kg x h)(-1), respectively. Concentration-dependent uptake of phenanthrene by roots of soybean, carrot and wheat can be described with Michaelis-Menten equation and the Km values for soybean, carrot and wheat are 0.117, 0.124 and 0.540 mg x L(-1). Hydroponic solution pH increases due to phenanthrene uptake and the trend in pH increase significantly correlates with those in uptake rate constant and Km value. In addition, the orders of uptake rate constant, Km value and pH increase for soybean, carrot and wheat are the same as that of uptake capability. Therefore, it is concluded that uptake rate constant, Km value and pH increase can be employed as indicators for the capability to take up PAHs by crop roots, and uptake rate constant and Km value are better indicators than pH increase because of less affecting factors.

[Dynamic changes of physicochemical properties in phenanthrene-contaminated soil under wheat and clover intercropping].

Soil physicochemical properties play an important role in the efficiency of phytoremediation and soil arability after phytoremediation. Soil pot experiments were conducted to investigate the dynamic changes of physicochemical properties in phenanthrene (a representative of polycyclic aromatic hydrocarbons)-contaminated soil under wheat and clover intercropping. The results showed that plants improved the pH values of phenanthrene-polluted soil with a maximum variation pH of 0.61. The difference in pH between wheat/clover intercropping and wheat/clover single cropping was not significant. Soil organic matter, total nitrogen, available nitrogen, total phosphorus, available phosphorus, cation exchange capacity and available potassium decreased over the experiment period due to biodecomposition and plant root absorption. The intercropping of wheat and alfalfa accelerated the consumption of the above-mentioned nutrients. And the decrease percentages ranged from 5.24% to 57.85%, more than those of wheat or alfalfa only planted with decrease percentages between 6.29% and 39.09%. In particular, soil available nitrogen and availiable phosphorus decreased more than the other nutrients with a maximum reduction percentage of 57.85%. Therefore, the application of nitrogen and phosphorus must be paid more attention during phytoremediation of polycyclic aromatic hydrocarbon-contaminated soil in the wheat and alfalfa intercropping system.

[Repair of scars in submaxillary region using expanded forehead axial flaps with fascia pedicles carrying bilateral frontal branches of superficial temporal artery and vein].

OBJECTIVE: To study the feasibility of applying expanded forehead axial flaps with fascia pedicles carrying bilateral frontal branches of superficial temporal artery and vein (expanded forehead axial flap with double pedicles in brief, EFAF-DP) in repairing scars in submaxillary region. METHODS: Sixteen patients with mandibular scars hospitalized in Department of Burns and Plastic Surgery of the First Hospital Affiliated to Fuzhou General Hospital in Nanjing Military Area Command from July 2005 to December 2009 were repaired with EFAF-DP. The operation consisted of 3 stages. Before operation, the location and course of superficial temporal arteries and veins (STAV) and their frontal and parietal branches were identified with Ultrasonic Doppler blood flow detector. In stage I, STAV were dissected from the frontalis muscle as a pedicle to form a skin soft tissue space to hold the dilator of a proper size. In stage II, after gradual dilation by repeated filling with saline, the dilator was removed. EFAF-DP was dissected to repair mandibular scar. Donor site was closed with sutures. In stage III, flap pedicles were divided and pruned. RESULTS: Flap sizes ranged from 25 cm × 6 cm to 33 cm × 16 cm. The duration of dilation was 3-5 months, with 3.6 months in average. Ten patients underwent the operation of EFAF-DP transplantation and cervical skin dilatation. All flaps survived with healing of wounds. Disorder of venous return at the distal end of one flap was seen after second stage surgery, and it was corrected after comprehensive treatment including relieving spasm and improving venous return. Donor site wounds healed with normally grown hair without cicatricial alopecia along the hairline. Few hairs grew around mandible in one female patient out of the three (no hair grew on flaps of other two patients). This female patient and two male patients requesting for beard plasty received laser depilation treatment 1 to 3 months after discharge, with good result. Other male patients received no special treatment for their beard, and they shaped their beard with shaver. Sixteen patients were followed up for 6 to 24 months, and the shape of the flaps and beard (excluding female patients) were satisfactory with good appearance, satisfactory skin color and texture. The mobility of neck was obviously improved. CONCLUSIONS: EFAF-DP provides bigger areas of a thin flap besides promoting vascularization of new vessels of flap. Extra expanded skin can be directly sutured at the fringe of hairline, which makes skin grafting unnecessary, and decreases the incidence of secondary deformity in donor sites. Some hair carried by the flaps can be directly used for beard reconstruction after rotation to help the male patients have a better appearance.

[Repair of cervicofacial scar by forehead expansive skin flap double-pedicled with superficial temporal vessels].

OBJECTIVE: To explore the clinical efficacy of using forehead expansive skin flap double-pedicled with superficial temporal vessels for repairing male cervicofacial scar. METHODS: From July 2005 to June 2009, 13 male patients with an average age of 27 years old (range: 21 - 38) were operated by the above method. The scar-repairing area was from 14 cm × 5 cm to 32 cm × 15 cm. The procedure was carried out in three stages. Firstly, ultrasound Doppler was used to detect and mark the location and orientation of superficial temporal artery. A proper cavity was created under the forehead muscle and then the appropriate expander embedded through the scalp incision. The expander was expanded first by injecting normal saline at 1 or 2 weeks post-operation. After that, the injection was repeated by 3 or 5 days. The volume ratio of injection to expander was (1.5-3.5):1. Secondly the forehead expansive skin flap was designed with proper hair follicle scalp pedicled by bilateral superficial temporal artery when the expansion was completed. After removal of the expander, the rectangle expansive skin flap with hair follicle scalp was transferred through the double pedicle. The cervicofacial scar was excised according to the size of the transferred expansive skin flap (25 cm × 6 cm to 32 cm × 9 cm). And the flap was adjusted with hair follicle scalp to the middle of the chin area in order to obtain the normal beard appearance. Donor site were closed directly. Thirdly, the pedicle skin flap were cut and restored after one month. RESULTS: The volume expanded for each expander ranged from 420 to 800 ml (mean: 660). The average expansion time was 4 months (range: 3 - 5). All flaps survived well. Donor site were closed directly. Both chin and beard looked normal. CONCLUSIONS: Repairing hypertrophic scar and reconstructing beard in cervicofacial area with forehead expansive skin flap pedicled by bilateral superficial temporal artery is a valuable and safe method. The donor site is scarless. And the reconstructed chin and beard are normal both functionally and aesthetically.

[Change in plasma brain natriuretic peptide and its clinical significance in burn patients after delayed fluid resuscitation of shock].

OBJECTIVE: To observe the early change in plasma brain natriuretic peptide (BNP) level in burn patients with long delayed fluid resuscitation of burn shock and its clinical significance. METHODS: Thirty-six burn patients with second and third degree of burn covering 32%-92% total body surface area were enrolled for the study, among them 10 patients were complicated with serious heart failure (heart failure group), and 26 patients rallied from shock after delayed fluid resuscitation without heart failure (stable group). The level of plasma BNP, lactate dehydrogenase (LDH), MB isoenzyme of creatine kinase (CK-MB), and left ventricle ejection fraction (LVEF) were determined at admission and 3 hours after hospitalization, and 24, 48, 72, 168 hours after the injury in both groups with electrochemiluminescence (ECL). RESULTS: Compared with stable group, the plasma BNP level (ng/L) of heart failure group at 3 hours after hospitalization, and 24, 48, 72 hours after the burn injury increased significantly (3 hours after hospitalization: 1 521.38+/-121.11 vs. 391.36+/-63.27, 24 hours after burn: 2 516.86+/-193.25 vs. 360.79+/-146.56, 48 hours after burn: 1 587.76+/-169.23 vs. 398.92+/-77.46, 72 hours after burn: 974.45+/-166.33 vs. 283.43+/-68.15, all P<0.01), the level of LVEF lowered significantly (3 hours after hospitalization : 0.33+/-0.03 vs. 0.58+/-0.09, 24 hours after burn: 0.36+/-0.09 vs. 0.60+/-0.10, 48 hours after burn: 0.35+/-0.08 vs. 0.62+/-0.11, 72 hours after burn: 0.39+/-0.10 vs. 0.64+/-0.10, all P<0.05). The levels of LDH (micromolxs(-1) xL(-1)) in stable group were 2.87+/-0.50 at admission, 3.02+/-0.43 3 hours after hospitalization, 4.02+/-0.87 24 hours after burn, 6.90+/-0.87 48 hours after burn, 3.64+/-0.75 72 hours after burn, 2.67+/-0.45 168 hours after burn while in heart failure group, they were 2.97+/-1.40, 3.84+/-0.37, 4.29+/-0.45, 8.50+/-0.38, 3.84+/-0.62, 2.30+/-0.38, respectively; and CK-MB (U/L) in stable group were 59.12+/-13.75 at admission, 70.39+/-10.72 3 hours after hospitalization, 79.29+/-17.27 24 hours after burn, 67.44+/-12.77 48 hours after burn, 30.28+/-7.13 72 hours after burn, 21.44+/-3.15 168 hours after burn while in heart failure group, they were 65.76+/-16.38, 81.46+/-7.92, 86.43+/-14.19, 72.53+/-11.27, 36.39+/-6.18, 22.85+/-7.26, respectively. No statistically significant difference was found in changes in both LDH and CK-MB between two groups (all P>0.05). CONCLUSION: Determination of the plasma BNP is a simple and useful method in detecting heart failure during resuscitation of shock after a serious burn injury.

Accumulation of phenanthrene by roots of intact wheat (Triticum acstivnm L.) seedlings: passive or active uptake?

BACKGROUND: Polycyclic aromatic hydrocarbons (PAHs) are of particular concern due to their hydrophobic, recalcitrant, persistent, potentially carcinogenic, mutagenic and toxic properties, and their ubiquitous occurrence in the environment. Most of the PAHs in the environment are present in surface soil. Plants grown in PAH-contaminated soils or water can become contaminated with PAHs because of their uptake. Therefore, they may threaten human and animal health. However, the mechanism for PAHs uptake by crop roots is little understood. It is important to understand exactly how PAHs are transported into the plant root system and into the human food chain, since it is beneficial in governing crop contamination by PAHs, remedying soils or waters polluted by PAHs with plants, and modeling potential uptake for risk assessment. RESULTS: The possibility that plant roots may take up phenanthrene (PHE), a representative of PAHs, via active process was investigated using intact wheat (Triticum acstivnm L.) seedlings in a series of hydroponic experiments. The time course for PHE uptake into wheat roots grown in Hoagland solution containing 5.62 microM PHE for 36 h could be separated into two periods: a fast uptake process during the initial 2 h and a slow uptake component thereafter. Concentration-dependent PHE uptake was characterized by a smooth, saturable curve with an apparent Km of 23.7 microM and a Vmax of 208 nmol g(-1) fresh weight h(-1), suggesting a carrier-mediated uptake system. Competition between PHE and naphthalene for their uptake by the roots further supported the carrier-mediated uptake system. Low temperature and 2,4-dinitrophenol (DNP) could inhibit PHE uptake equally, indicating that metabolism plays a role in PHE uptake. The inhibitions by low temperature and DNP were strengthened with increasing concentration of PHE in external solution within PHE water solubility (7.3 muM). The contribution of active uptake to total absorption was almost 40% within PHE water solubility. PHE uptake by wheat roots caused an increase in external solution pH, implying that wheat roots take up PHE via a PHE/nH+ symport system. CONCLUSION: It is concluded that an active, carrier-mediated and energy-consuming influx process is involved in the uptake of PHE by plant roots.

[Effect of reduced glutathione on impairment of hepatic function after delayed resuscitation of severe burn shock].

OBJECTIVE: To investigate the protective effects of the reduced glutathione (GSH) on hepatic injury after delayed resuscitation in patients with severe burn. METHODS: Forty severely burned patients with hepatic injury after delayed resuscitation were randomly divided into two groups: treatment group (T, 20 cases) and control group (C, 20 cases). In the T group, the patients were treated with GSH for 7-14 days, while the patients in the C group were treated with same quantity of "energy mixture" as control. The venous blood sample of each patient of the two groups was collected and examined for the content of alanine aminotransferase (ALT), aspartate aminotransferase (AST), gamma-glutamyltranspeptidase (gamma-GT), alkaline phosphatase (ALP), total bilirubin (TBIL), and direct bilirubin (DBIL) before the treatment and 7 days and 14 days after the treatment. RESULTS: The contents of the enzymes in the T group were significantly decreasing gradually in all patients after 7 days and 14 days of treatment (P<0.05 or P<0.01). In the C group, the enzymes showed a decrease in quantity 7 days after the management but without statistical significance. However, they still showed significant decrease on 14th day with the "energy mixture" treatment (all P<0.05). After 14 days of the treatment, ALT, AST, gamma-GT, TBIL and DBIL showed obvious decrease in the T group compared to the C group (all P<0.05), but there was no significant difference in ALP between the two groups. CONCLUSION: The results of this study indicates that early use of GSH may be beneficial in the management of protecting hepatic injury after delayed resuscitation for severe burn.

[Enzymatic activities of phenanthrene contaminated soil in wheat and clover intercropping system].

The dynamic changes of soil enzymatic activities during remediation of phenanthrene contaminated soil with clover or clover and wheat were investigated with pot experiments. Clover and wheat increased the activities of soil sucrase, polyphenol oxidase, urease and phosphatase with an increase rate in the range of 14.72%-46.52%, but inhibited the catalase activity with an inhibition rate in the range of 36.13%-94.79%. Sucrase and polyphenol oxidase reached the maximum activity values at the 14th day, and urease and phosphatase at the 21th day. Catalase got to the minimum activity value at the 7th day. In the light of these, catalase was relatively more sensitive to phenanthrene than the other enzymes, and could be employed as a key indicator to evaluate the risk of polycyclic aromatic hydrocarbon contaminated soil during remedying. Sucrase and polyphenol oxidase activities in wheat and clover intercropping system were significantly higher than in wheat or clover single-cropping system. Furthermore, there was a good negative correlation between catalase and sucrase (r = - 0.482), and polyphenol oxidase (r = -0.599), and urease (r = -0.329), and phosphatase (r = -0.297). Nonetheless, a good positive correlation existed among sucrase, polyphenol oxidase, urease and phosphatase. It is concluded that in the process of phytoremediation, soil enzymes can be employed as indicators for soil quality, it is not necessary to monitor each enzymatic activity, but to the activity of a key enzyme.

[Effect of dissolved organic matter on phenanthrene sorption-desorption in soil system].

Batch experiments were conducted to investigate effect of dissolved organic matter (DOM) on the adsorption and desorption behavior of Phenanthrene (Phe) in a soil-water system. It was found that three natural DOM derived from pig manure (PM), sewage sludge (SS), green manure (GM) and a kind of surfactant Tween-80 can reduced sorption of Phenanthrene significantly onto the tested soil. Within the selected concentration of the Phenanthrene and DOM in this study, the sorption quantity has a negative-linear correlativity with the concentration of DOM (r(PM) = - 0.988 8, r(SS) = - 0.982 6, r(Tween-80 = - 0.974 3, r(GM) = - 0.990 5). The inhibition of Phenanthrene sorption caused by DOM of PM origin was more significant than that of SS origin and GM origin for the same soil. Phenanthrene sorption isotherm could be described well by the Freundlich equation. It implied that DOM can affect the environmental behaviors of Phenanthrene in soil.

[Impact of dissolved organic matter on plant uptake of phenanthrene and its mechanisms].

Hydroponic assays were conducted to investigate the influence of dissolved organic matter on uptake of phenanthrene by wheat as well as its mechanisms. The results showed that, under hydroponic condition, phenanthrene impairment of plant growth occurred with wheat growth inhibited rate of 18.01%. The impairment would be greatly enhanced in the presence of dissolved organic matter (DOM) derived from pig manure, and the inhibited rate increased to 24.38%. Wheat could uptake and accumulate phenanthrene in the nutrient solution, which could be escalated by DOM, as indicated by wheat root bioconcentration factor being increased to 37.63 L x kg(-1) in the presence of DOM from 2.84 L x kg(-1) in the absence of DOM. At the same time, DOM could facilitate phenanthrene translocation from plant roots to the upper. As a result, the pH value of nutrient solution could increase by more than 1 unit when the co-existence of DOM and phenanthrene occurred in solution, suggesting that H+ -phenanthrene cotransport system is involved in the uptake of phenanthrene by plants. A synergism was also found between wheat uptakes of phenanthrene and inorganic nutrients, Moreover, DOM accelerated markedly the synergism. It is concluded that DOM affects the uptake of phenanthrene by plants and the environmental behaviors of phenanthrene.

[Influence of dissolved organic matter on the eco-toxicity of phenanthrene in a soil].

Biological and physico-chemistry experiments were conducted to study the effects of dissolved organic matter (DOM) on eco-toxicity of phenanthrene in a soil. The results showed that DOM was a kind of surfactant. The sensitive range of phe inhibiting wheat root elongation was from 0 to 200 mg/kg, and median inhibition concentration (IC50) was 200 mg/kg. In the presence of DOM, the eco-toxicity of phe could be alleviated and the inhabited degree was related to the content of hydrophobic components and surface activity. This effect could be strengthened by the high concentration of DOM. As a kind of hydrophobic organic compound, phe could reduce the moisture of topsoil, and DOM would slightly increase the moisture of topsoil polluted by phe. It was concluded that DOM could lighten the eco-toxicity of phe in soil.

[An early comprehensive prevention and treatment of sepsis in severely burned patients with delayed fluid resuscitation].

OBJECTIVE: To study an early comprehensive prevention and treatment of sepsis in severely burned patients with delayed fluid resuscitation. METHODS: From January 1990 to December 2001, 72 cases of patients with delayed fluid resuscitation were admitted to our burn department. Two different periods were divided and analyzed retrospectively. The first period was from January 1990 to December 2001 and the span of the second period was from January 1995 to December 2001. RESULTS: (1)The mortality rate and incidence of sepsis in the second period (6.5 percent and 17.4 percent) were significantly lower than those of the first period (23.0 percent and 57.7 percent, P<0.05 and P<0.01). (2)The time of wound healing in the second period was (1.9+/-0.9) hours, it was lower than that of the first period (6.6+/-2.5) hours. (3)The serum contents of tumor necrosis factor (TNF) and blood lactic acid (BLA) were increased at all times in two periods and were markedly increased in the first period (all P<0.01). CONCLUSION: Our data demonstrated that measures adopted in the second period for patients with delayed fluid resuscitation, including early excision, early rapid adequate resuscitation, early enteral feeding, increased immunity function, early applying antibactials, xenotransfusion of ultraviolet-irradiated blood, application of recombinant human-growth factor (rh-GH), epidermal growth factor (EGF), basic fibroblast growth factor (bFGF), are beneficial to the prevention and treatment of sepsis in severely burned patients with delayed fluid resuscitation.