Effects of Preoperative Oral Carbohydrate Electrolyte Drinks on Preoperative Hypokalemia Incidence in Patients Scheduled for Laparoscopic Colorectal Resection: A Three-Arm Randomized Clinical Trial.

PURPOSE: In our previous study, hypokalemia incidence was high in patients scheduled for laparoscopic colorectal resection. This trial was conducted to verify the effects of preoperative carbohydrate drinks containing potassium in these patients. DESIGN: A three-arm randomized controlled design was used. METHODS: Patients were randomly assigned to control, placebo, and treatment groups. In the control group, patients fasted from midnight. In the placebo group, patients fasted from midnight and received carbohydrate drinks 2 to 3 hours before surgery. In the treatment group, patients fasted from midnight and received carbohydrate drinks containing potassium supplementation 2 to 3 hours before surgery. The primary outcome was the incidence and severity of preoperative hypokalemia. Other outcomes included postoperative gastrointestinal function, including the time to postoperative first flatus (FFL) and first feces (FFE), and other complications. FINDINGS: The final analysis included 122 participants. The incidence of preoperative hypokalemia in the treatment group was significantly lower than that in the control and placebo groups (50% vs 88.1% vs 77.5%, P < .001). The severity of hypokalemia in the control and placebo groups was greater than that in the treatment group. No regurgitation or aspiration occurred in the three groups. No significant differences were observed among the three groups regarding time to FFL and FFE. CONCLUSIONS: Preoperative carbohydrate drinks containing potassium significantly reduced the incidence of preoperative hypokalemia and improved preoperative thirst and hunger, but did not reduce the postoperative time to FFL and FFE or length of hospital stay. However, as part of the enhanced recovery after surgery protocol, preoperative carbohydrate drinks containing potassium should be considered, as early as first admittance to hospital.

Single-Cell RNA-Sequencing Atlas Reveals the Tumor Microenvironment of Metastatic High-Grade Serous Ovarian Carcinoma.

Ovarian cancer is the most common and lethal gynecological tumor in women worldwide. High-grade serous ovarian carcinoma (HGSOC) is one of the histological subtypes of epithelial ovarian cancer, accounting for 70%. It often occurs at later stages associated with a more fatal prognosis than endometrioid carcinomas (EC), another subtype of epithelial ovarian cancer. However, the molecular mechanism and biology underlying the metastatic HGSOC (HG_M) immunophenotype remain poorly elusive. Here, we performed single-cell RNA sequencing analyses of primary HGSOC (HG_P) samples, metastatic HGSOC (HG_M) samples, and endometrioid carcinomas (EC) samples. We found that ERBB2 and HOXB-AS3 genes were more amplified in metastasis tumors than in primary tumors. Notably, high-grade serous ovarian cancer metastases are accompanied by dysregulation of multiple pathways. Malignant cells with features of epithelial-mesenchymal transition (EMT) affiliated with poor overall survival were identified. In addition, cancer-associated fibroblasts with EMT-program were enriched in HG_M, participating in angiogenesis and immune regulation, such as IL6/STAT3 pathway activity. Compared with ECs, HGSOCs exhibited higher T cell infiltration. PRDM1 regulators may be involved in T cell exhaustion in ovarian cancer. The CX3CR1_macro subpopulation may play a role in promoting tumor progression in ovarian cancer with high expression of BAG3, IL1B, and VEGFA. The new targets we discovered in this study will be useful in the future, providing guidance on the treatment of ovarian cancer.

Different preoperative fluids do not affect the hemodynamic status but gastric volume: results of a randomized crossover pilot study.

BACKGROUND AND OBJECTIVE: Inferior vena cava (IVC) examination has been reported as a noninvasive method for evaluating the hemodynamic state. We conducted this crossover pilot study to investigate the effects of the administration of water and high-carbohydrate-containing fluids on the hemodynamic status of volunteers through collapsibility index of IVC (IVCCI) measurement. METHODS: Twenty volunteers were randomly assigned to a water or high-carbohydrate group according to computer-generated random numbers in a 1:1 ratio. In the water group, volunteers received water (5 mL/kg), and in the high-carbohydrate group, patients received carbohydrate drinks (5 mL/kg). Respiratory variations in the IVC diameter, gastric volume, and blood pressure and heart rates in erect and supine positions were measured at admission (T1), 1 h (T2), 2 h (T3), 3 h (T4), and 4 h (T5). RESULTS: When considering participants with an IVCCI of more than 42%, there were no significant differences between the water and carbohydrate drink groups at each time point (all p > 0.05). At T2, more participants had an empty stomach in water group than in carbohydrate drink group (p < 0.001). At T3, 30% of the participants could not empty their stomachs in carbohydrate drink group. However, with regard to the number of volunteers with empty stomach at T3, there was no significant difference between water and carbohydrate drink group. Repeated measures data analysis demonstrated that IVCCI showed no significant differences over time (p = 0.063 for T1-T5). There were no differences between water and carbohydrate drinks (p = 0.867). CONCLUSION: Our results suggested that neither water nor carbohydrate drinking affected the hemodynamic status through IVCCI measurement over time, up to 4 h after drinking. Furthermore, carbohydrate drinking might delay gastric emptying at 1 h, but not 2 h after drinking, in comparison with water.

Effects of liberal oral intake on postoperative outcomes after elective laparoscopic gynaecological surgery: A randomised controlled clinical trial.

BACKGROUND: Women are at risk of postoperative nausea and vomiting (PONV) after laparoscopic gynaecological surgery. Traditionally, patients who undergo laparoscopic gynaecological surgery are only allowed to initiate oral intake after return of bowel function, including bowel sounds or passage of flatus or stool. The present study was designed to assess the effect of liberal oral intake immediately after discharge from the post-anaesthesia care unit (PACU) on PONV incidence in patients who underwent elective laparoscopic gynaecological surgery. METHODS: In total, 174 patients (aged 20-64 years) were randomly assigned to the traditional and liberal groups. In the traditional group, patients were allowed to initiate oral intake 6 h after discharge from the PACU. In the liberal group, patients were allowed oral intake immediately after discharge from the PACU. The primary outcome was the incidence of PONV 48 h after surgery. Secondary outcomes included ileus incidence, total dose of postoperative opiate (sufentanil) use, time to postoperative first flatus (FFL), first out-of-bed mobilisation and the duration of postoperative hospitalisation stay. RESULTS: Incidence of PONV was not significantly different between both groups (32.18% vs. 33.33%, p = 0.872). Time to FFL in the liberal group was significantly shorter than that in the traditional group (14.82 ± 0.91 h vs. 17.50 ± 0.96 h, p = 0.024). The postoperative pain score at 48 h after surgery was significantly lower in the liberal group than that in the traditional group (2.48 ± 0.17 vs. 3.20 ± 0.19, p = 0.008) without an increase in sufentanil use (89.32 ± 1.02 µg vs. 89.92 ± 1.16 µg, p = 0.702). No ileus occurred in either group. When considering the time of actually return to regular diet, initiating regular diet no more than 6 h after discharge from PACU significantly shortened the time to first out-of-bed mobilisation (11.18 ± 1.01 h vs. 15.05 ± 0.70 h, p = 0.003). CONCLUSIONS: Our results indicate that liberal oral intake after discharge from the PACU in patients aged 20-64 years who underwent gynaecological surgery is safe and beneficial and supports the rationale for a more liberal diet regime postoperatively.

Preoperative Fasting Guidelines: Where Are We Now? Findings From Current Practices in a Tertiary Hospital.

PURPOSE: New evidence-based fasting guidelines have been published in recent years. However, while water and solid food fasting times before anesthesia are recommended to be 2 and 6 hours, respectively, these times are often longer in clinical practice. This study aimed to investigate the awareness and implementation of the fasting guideline recommendations among nurses and anesthesiologists, as well as evaluate the actual fasting durations in patients in a tertiary hospital. DESIGN: A cross-sectional study was used. METHODS: Questionnaires were designed to collect the knowledge of fasting time among registered anesthesiologists and nurses. Data on the instructed and actual fasting durations among patients scheduled for elective surgery were evaluated. FINDINGS: Approximately half of the nurses indicated that solid food fasting durations were shorter than 6 hours or longer than 8 hours, and two-thirds indicated that clear fluid fasting durations were shorter than 2 hours or longer than 4 hours. However, in clinical practice, nurse-instructed fasting durations were longer than what they knew was optimal. The anesthesiologists also prescribed longer fasting durations than the minimum fasting duration recommended. The actual fasting durations of the patients were significantly longer than the nurse-instructed fasting durations for solid food (13.41 ± 2.64 vs 9.87 ± 2.20 hours, P < .001) and clear fluids (10.27 ± 3.67 vs 8.98 ± 2.90 hours, P < .001). The nurse-instructed durations were significantly longer than the anesthesiologist-instructed durations according to the statements of patients (9.87 ± 2.20 vs 9.00 ± 2.00 hours for solid food, P < .001; 8.98 ± 2.90 vs 6.15 ± 3.25 hours for clear fluids, P < .001). CONCLUSIONS: Excessive fasting durations were observed among patients. Anesthesiologists and nurses must work together to ensure that updated fasting instructions are implemented in routine clinical practice.

High rate of burnout among residents under standardized residency training in a tertiary teaching hospital of middle China: Results from a cross-sectional survey.

Burnout has been commonly observed in health care workers. Though research has been conducted involving burnout among doctors in China, few studies have focused on residents during standardized residency training (SRT). The professional status of the residents during SRT remains largely unclear. The present study was conducted in order to clarify the prevalence and potential risk factors of burnout in residents during SRT.An electronic questionnaire comprised 2 parts. The first part was designed to collect some basic characteristic information. Maslach Burnout Inventory-Human Services Survey was included in the second part.As many as 71.05% residents had at least 1 scale of burnout. Emotional exhaustion (EE) was found in 55.6% residents, depersonalization (DP) in 29.7% and reduced personal accomplishment (RPA) in 41.6%. Being older than 27, senior SRT year, working time more than 60 hours per week and poor sleeping quality was independently associated with at least on scale of burnout. Being unable to receive timely supervisor support significantly increased the probability of DP and EE. Not having friends at work or feeling cared for by the hospital were independently related to all 3 symptoms of burnout as well as overall burnout.Burnout rate is high in residents under SRT from middle part of China. Organizational, professional, and social support was demonstrated critical by the potential roles in protecting against burnout. Residents with burnout were prone to considering turnover. Strategies for managing burnout related factors among residents should be focused in future studies.

Dexmedetomidine alleviated neuropathic pain in dorsal root ganglion neurons by inhibition of anaerobic glycolysis activity and enhancement of ROS tolerance.

Neuropathic pain is a kind of chronic pain that is triggered or caused primarily by damage to the nervous system and neurological dysfunction. It's known that dexmedetomidine is a new type of highly selective alpha2-adrenoceptor agonist with sedation, anti-anxiety, analgesic and other effects. However, the function and mechanism of dexmedetomidine on neuropathic pain are not clear. Rat DRG neurons were isolated and identified using immunofluorescence assay. Following treatment with H2O2, dexmedetomidine or ROS inhibitor (NAC), the apoptosis and ROS levels were examined by flow cytometery; apoptosis- and anaerobic glycolysis-related proteins were determined by Western blot assay; glucose consumption, pyruvic acid, lactic acid and ATP/ADP ratios were also measured. The results revealed that dexmedetomidine inhibited H2O2-induced apoptosis and reactive oxygen species (ROS) in rat DRG neurons and in addition, dexmedetomidine down-regulated the expression levels of anaerobic glycolysis-related proteins, significantly reduced glucose, pyruvic acid and lactic acid levels. It also increased the ATP/ADP ratio in H2O2-treated rat dorsal root ganglion (DRG) neurons. Moreover, we also demonstrated that ROS inhibitor (NAC) also inhibited H2O2-induced apoptosis and anaerobic glycolysis in rat DRG neurons. In conclusion, dexmedetomidine suppressed H2O2-induced apoptosis and anaerobic glycolysis activity by inhibiting ROS, in rat DRG neurons. Therefore, dexmedetomidine might play a pivotal role in neuropathic pain by the inhibition of ROS.

Dexmedetomidine Attenuates Orthotopic Liver Transplantation-Induced Acute Gut Injury via α 2-Adrenergic Receptor-Dependent Suppression of Oxidative Stress.

Patients with orthotopic liver transplantation (OLT) frequently develop acute gut injury (AGI), and dexmedetomidine (Dex) has been reported to exert a protective effect against AGI. We investigated whether Dex protects against AGI through antioxidative stress effects by the Nrf2/HO-1 antioxidative signaling pathway. Rats were randomly allocated into a sham group and six orthotopic autologous liver transplantation (OALT) groups receiving different doses of Dex together with/without α 2-adrenergic receptor (AR) blockers. Intestinal tissues were collected to visualize the barrier damage and to measure the indexes of oxidative stress. For in vitro studies, rat intestinal recess epithelial cells (IEC-6) underwent hypoxia/reoxygenation (H/R), and the protective role of Dex was evaluated after α 2A-AR siRNA silencing. OALT resulted in increased oxidative stress, significant intestinal injury, and barrier dysfunction. Dex attenuated OALT-induced oxidative stress and intestinal injury, which was abolished by the pretreatment with the nonspecific α 2A-AR siRNA blocker atipamezole and the specific α 2A-AR siRNA blocker BRL-44408, but not by the specific 2B/C-AR siRNA blocker ARC239. Silencing of α 2A-AR siRNA also attenuated the protective role of Dex on alleviating oxidative stress in IEC-6 cells subjected to H/R. Dex exerted its protective effects by activating Nrf2/HO-1 antioxidative signaling. Collectively, Dex attenuates OALT-induced AGI via α 2A-AR-dependent suppression of oxidative stress, which might be a novel potential therapeutic target for OALT-induced AGI.

Anesthesiologists' acquisition of hepatitis B virus infection: Risk and prevention.

Occupational exposure remains a serious problem for medical staff, especially those working in operation rooms. Hepatitis B virus (HBV) is prevalent in patients undergoing surgery, and anesthesiologists are at risk of occupational acquisition of blood-borne HBV infection. To the best of our knowledge, there are no data about HBV prevalence and vaccinations, as well as attitudes toward sharp injuries and gloving among anesthesiologists in China, where the HBV prevalence is high. To clarify these, the present study was conducted.An electronic questionnaire including HBV markers, gloving during practice, and reporting patterns of sharp injuries was created and sent to anesthesiologists.After excluding 10 uncompleted questionnaires, 1739 questionnaires were included in the final analysis. Of all analyzed anesthesiologists, 1599 (91.9%) had experienced sharp injuries, and 1313 (75.5%) had experienced >1 sharp injury. Considering HBV vaccination histories, 1381 anesthesiologists (79.4%) received 3 vaccination doses, and only half of the immunized anesthesiologists received reminder HBV vaccination doses after work before exposure. There were 696 anesthesiologists (40.0% of all participants) who were ever exposed to HBV, and nearly two-thirds of them (440) were exposed to HBV more than once. There was a more positive attitude toward gloving and double-gloving to reduce HBV exposure.The incidence of occupational HBV exposure among anesthesiologists is high, and its threat should be considered. HBV vaccinations and adherence to postexposure guidelines are recommended. The high prevalence of sharp injuries during anesthesia practice highlights the importance of safe anesthesia practices, such as gloving or double-gloving, especially when in contact with high-risk body fluids.

Perioperative application of dexmedetomidine for postoperative systemic inflammatory response syndrome in patients undergoing percutaneous nephrolithotomy lithotripsy: results of a randomised controlled trial.

OBJECTIVE: Our previous retrospective study demonstrated that perioperative dexmedetomidine (Dex) administration was associated with low systemic inflammatory response syndrome (SIRS) incidence. The present study was designed to investigate whether perioperative administration of Dex decreases the incidence of postpercutaneous nephrolithotomy lithotripsy (PCNL) SIRS in patients who undergo PCNL. DESIGN: A randomised controlled trial was designed. PARTICIPANTS: A total of 190 patients were randomly assigned to receive Dex (DEX group, n=95) or saline control (CON group, n=95) and completed the study. In the DEX group, Dex was loaded (1 µg/kg) before anaesthesia induction and was infused (0.5 µg/kg/h) during surgery. OUTCOMES: The incidences of postoperative SIRS were recorded. Serum interleukin-6 (IL-6) and tumour necrosis factor α(TNF-α) were measured. RESULTS: The incidence rates of SIRS were significantly lower in the DEX group than in the CON group (35.8% vs 50.5%, p=0.04). No patients developed sepsis in either group. These results might be attributed to inhibition of inflammatory responses and the resulting lower serum levels of IL-6 and TNF-α, caused by Dex administration. However, compared with the CON group, the lower incidence rate of SIRS in the DEX group did not result in better outcomes, such as shorter postoperative hospitalisation stays and lower costs. CONCLUSION: The present study showed that Dex administration during PCNL might be beneficial for decreasing the incidence of SIRS through inhibiting the release of inflammatory mediators, but not clinical consequences such as postoperative hospitalisation duration and costs. Further effects of Dex administration on SIRS in patients who are scheduled for PCNL should be explored in future studies. TRIAL REGISTRATION NUMBER: ChiCTR-ICR-15006167.

Prevalence and risk factors for hypokalemia in patients scheduled for laparoscopic colorectal resection and its association with post-operative recovery.

BACKGROUND: Perioperative serum potassium levels are closely associated with postoperative clinical outcomes after gastrointestinal surgery. The aim of our retrospective study was to identify the prevalence and risk factors for preoperative hypokalemia (before pneumoperitoneum) and to evaluate the influence of preoperative hypokalemia on the recovery of postoperative gastrointestinal function. METHODS: In this retrospective study, patients scheduled for laparoscopic colorectal resection from November 11 2014 to October 20 2016, were considered for inclusion. A blood potassium level between 3.5 and 5.5 mmol/L was defined as normal, with levels between 3.0 to 3.5 mmol/L, 2.5 to 3.0 mmol/L and < 2.5 mmol/L considered as slight, moderate, and severe level of hypokalemia. The factors including age, gender, ASA grade, BMI, hypertension, diabetes, anti-hypertension drugs, lactose oral soluble, oral cathartics, oral cathartics, cathartic enemas, and blood potassium level before gastrointestinal preparation which might be associated with blood potassium level before pneumoperitoneum were analysed. The time to postoperative first flatus (FFL) and first feces (FFE) was compared between patients with and without hypokalemia. RESULTS: The final analysis was based on the data of 108 patients. Hypokalemia was identified in 70.37% patients, with the following distribution of blood potassium levels before pneumoperitoneum: slight, 49 (45.37%) patients; moderate, 23 (21.30%); and severe, 4 (3.70%) patients. Hypokalemia was significantly associated with hypertension and the use of ≥2 types of oral cathartics for preoperative gastrointestinal preparation. With treatment, potassium levels recovered to normal levels in all patients within 48 h postoperatively. Hypokalemia was associated with a longer postoperative time to first feces, compared to patients with a normal potassium level before pneumoperitoneum. CONCLUSIONS: Our findings underlie the importance of early monitoring and management of serum potassium levels in these patients.

Intraoperative dexmedetomidine attenuates postoperative systemic inflammatory response syndrome in patients who underwent percutaneous nephrolithotomy: a retrospective cohort study.

PURPOSE: Dexmedetomidine (DEX) has been reported to attenuate inflammation in rats. The present retrospective cohort study aimed to investigate whether intraoperative administration with DEX could reduce the incidence of postoperative systemic inflammatory response syndrome (SIRS) in patients following percutaneous nephrolithotomy (PCNL). PATIENTS AND METHODS: A total of 251 patients were included in the analysis. Among these patients, 175 received intravenous DEX infusion during the intraoperative period and 76 did not. The primary outcome measures were the incidences of postoperative SIRS and fever. Secondary outcomes included patient-controlled analgesia (tramadol) requirements, length of postoperative hospitalization stay, serum creatinine (Scr) and serum blood urea nitrogen (BUN) concentration, and adverse events (bradycardia, hypotension, renal artery thrombosis). RESULTS: Administration of DEX not only significantly attenuated the incidence of SIRS and fever (P=0.029, P=0.042, respectively), but also reduced analgesia requirements (P=0.028). The length of postoperative hospitalization stay, Scr and BUN concentration, and adverse events did not differ significantly between the two groups. Further univariate and multivariate logistic regression analysis indicated that intraoperative DEX administration was a protective factor against SIRS after PCNL (OR 0.476 [95% CI: 0.257-0.835]; P=0.019). CONCLUSION: Intraoperative administration of DEX might be associated with reductions in the incidences of SIRS and fever after PCNL.

Multiple Method Analysis of TiO2 Nanoparticle Uptake in Rice (Oryza sativa L.) Plants.

Understanding the translocation of nanoparticles (NPs) into plants is challenging because qualitative and quantitative methods are still being developed and the comparability of results among different methods is unclear. In this study, uptake of titanium dioxide NPs and larger bulk particles (BPs) in rice plant (Oryza sativa L.) tissues was evaluated using three orthogonal techniques: electron microscopy, single-particle inductively coupled plasma mass spectroscopy (spICP-MS) with two different plant digestion approaches, and total elemental analysis using ICP optical emission spectroscopy. In agreement with electron microscopy results, total elemental analysis of plants exposed to TiO2 NPs and BPs at 5 and 50 mg/L concentrations revealed that TiO2 NPs penetrated into the plant root and resulted in Ti accumulation in above ground tissues at a higher level compared to BPs. spICP-MS analyses revealed that the size distributions of internalized particles differed between the NPs and BPs with the NPs showing a distribution with smaller particles. Acid digestion resulted in higher particle numbers and the detection of a broader range of particle sizes than the enzymatic digestion approach, highlighting the need for development of robust plant digestion procedures for NP analysis. Overall, there was agreement among the three techniques regarding NP and BP penetration into rice plant roots and spICP-MS showed its unique contribution to provide size distribution information.

High Adsorption of Sulfamethoxazole by an Amine-Modified Polystyrene-Divinylbenzene Resin and Its Mechanistic Insight.

Sulfamethoxazole (SMZ) adsorption by a series of amine-modified polystyrene-divinylbenzene resins (PSA/B/C/D) was investigated. All resins showed a similar pH dependent adsorption of SMZ but their capacities were linearly related with the contents of primary amines (-NH2) rather than secondary amines (-NH-). Mechanisms of SMZ adsorption by PSA (highest -NH2 content) were discussed as an example. Due to comparable pKa, H-bonding interactions of -NH2(0) with SMZ(0) (regular H-bond) and SMZ(-) (negative charge-assisted H-bond, (-)CAHB) successively contributed most adsorption (pH 4-9). At weakly acidic pH, -NH2(0) was partially protonated and electrostatic attraction between -NH3(+) and SMZ(-) occurred concurrently, but could be hindered by increased loading of SMZ(0). Hydrophobic/ π-π interactions were not major mechanisms as phenanthrene and nitrobenzenes had little effect on SMZ adsorption. At alkaline pH, where SMZ(-) and -NH2(0) prevailed, adsorption was accompanied by the stoichiometric (∼1.0) proton exchange with water, leading to OH(-) release and the formation of (-)CAHB [SO2N(-)···H···NH2]. The interaction and SMZ spatial distribution in the resin-phase were further confirmed by FTIR and Raman spectra. SMZ was uniformly adsorbed on external and interior surfaces. SMZ adsorption by PSA had low-interference from other coexistent matter, but high stability after multiple regenerations. The findings will guide new adsorbent designs for selectively removing target organics.

Response difference of transgenic and conventional rice (Oryza sativa) to nanoparticles (γFe2O3).

Nanoparticles (NPs) are an increasingly common contaminant in agro-environments, and their potential effect on genetically modified (GM) crops has been largely unexplored. GM crop exposure to NPs is likely to increase as both technologies develop. To better understand the implications of nanoparticles on GM plants in agriculture, we performed a glasshouse study to quantify the uptake of Fe2O3 NPs on transgenic and non-transgenic rice plants. We measured nutrient concentrations, biomass, enzyme activity, and the concentration of two phytohormones, abscisic acid (ABA) and indole-3-acetic acid (IAA), and malondialdehyde (MDA). Root phytohormone inhibition was positively correlated with Fe2O3 NP concentrations, indicating that Fe2O3 had a significant influence on the production of these hormones. The activities of antioxidant enzymes were significantly higher as a factor of low Fe2O3 NP treatment concentration and significantly lower at high NP concentrations, but only among transgenic plants. There was also a positive correlation between the treatment concentration of Fe2O3 and iron accumulation, and the magnitude of this effect was greatest among non-transgenic plants. The differences in root phytohormone production and antioxidant enzyme activity between transgenic and non-transgenic rice plants in vivo suggests that GM crops may react to NP exposure differently than conventional crops. It is the first study of NPs that may have an impact on GM crops, and a realistic significance for food security and food safety.

The Effects of Fe2O3 Nanoparticles on Physiology and Insecticide Activity in Non-Transgenic and Bt-Transgenic Cotton.

As the demands for nanotechnology and nanoparticle (NP) applications in agriculture increase, the ecological risk has drawn more attention because of the unpredictable results of interactions between NPs and transgenic crops. In this study, we investigated the effects of various concentrations of Fe2O3 NPs on Bt-transgenic cotton in comparison with conventional cotton for 10 days. Each treatment was conducted in triplicate, and each experiment was repeated three times. Results demonstrated that Fe2O3 NPs inhibited the plant height and root length of Bt-transgenic cotton and promoted root hairs and biomass of non-transgenic cotton. Nutrients such as Na and K in Bt-transgenic cotton roots increased, while Zn contents decreased with Fe2O3 NPs. Most hormones in the roots of Bt-transgenic cotton increased at low Fe2O3 NP exposure (100 mg⋅L(-1)) but decreased at high concentrations of Fe2O3 NPs (1000 mg⋅L(-1)). Fe2O3 NPs increased the Bt-toxin in leaves and roots of Bt-transgenic cotton. Fe2O3 NPs were absorbed into roots, then transported to the shoots of both Bt-transgenic and non-transgenic cottons. The bioaccumulation of Fe2O3 NPs in plants might be a potential risk for agricultural crops and affect the environment and human health.

Multiwalled carbon nanotubes and c60 fullerenes differentially impact the accumulation of weathered pesticides in four agricultural plants.

The effect of multiwalled carbon nanotubes (MWCNT) or C60 fullerenes on the uptake of weathered chlordane or DDx (DDT + metabolites) by Cucurbita pepo (zucchini), Zea mays (corn), Solanum lycopersicum (tomato), and Glycine max (soybean) was investigated. The plants were grown in 50 g of soil with weathered chlordane (2150 ng/g) and DDx (118 ng/g) that was amended with 0, 500, 1000, or 5000 mg/kg MWCNT or C60. After 28 d, the root and shoot content of chlordane components and DDx was determined by GC-MS. Zucchini and tomato growth were unaffected by carbon nanomaterial coexposure, although C60 at 500 mg/kg reduced corn and soybean biomass by 36.5-45.0%. Total chlordane content ranged from 1490 (tomato) to 4780 (zucchini) ng; DDx amounts ranged from 77.8 (corn) to 395 ng (zucchini). MWCNT coexposure decreased chlordane and DDx accumulation 21-80% across all crops, depending on species and nanotube concentration. Conversely, C60 had species- and contaminant-specific effects on pesticide uptake, ranging from complete suppression of DDx uptake (corn/tomato) to 34.9% increases in chlordane accumulation (tomato/soybean). The data show that pesticide accumulation varies greatly with crop species and carbon nanomaterial type/concentration. These findings have implications for food safety and for the use of engineered nanomaterials in agriculture.

Fullerene-enhanced accumulation of p,p'-DDE in agricultural crop species.

The effect of C(60) fullerene exposure on the accumulation of dichlorodiphenyldichloroethylene (p,p'-DDE; DDT metabolite) by Cucurbita pepo L. (zucchini), Glycine max L. (soybean), and Solanum lycopersicum L. (tomato) was determined. The plants were grown in 125 mL jars of vermiculite amended with 0 or 40 mg of C(60) fullerenes. Prior to planting, the jars were amended with 40 mL solution containing 100 ng/mL of p,p'-DDE with 0 or 100 mg/L humic acid. During three weeks of growth, plants were watered with the same p,p'-DDE containing solutions. Total shoot p,p'-DDE levels in nonfullerene exposed tomato, soybean, and zucchini were 26.9, 131, and 675 ng, respectively; total root DDE content for the three plants was 402, 5970, and 5830 ng, respectively. Fullerenes increased the shoot p,p'-DDE content of zucchini by 29%; contaminant levels in soybean shoots were decreased by 48% but tomato shoot content was unaffected. The root and total plant p,p'-DDE content of all three species was significantly increased by fullerene exposure; enhanced contaminant uptake ranged from 30 to 65%. Humic acid, regardless of fullerene presence or plant type, significantly decreased the p,p'-DDE uptake. Fullerenes were detected in the roots of all plants but were not detected in plant shoots in the initial study. In a follow up study with zucchini designed to maximize biomass for extraction, over half the analyzed stems contained fullerenes at 60.5 to 4490 ng/g. These findings show that the carbon-based nanomaterials may significantly alter the accumulation and potentially the toxicity of cocontaminants in agricultural systems.

Sorption of chlorophenols onto fruit cuticles and potato periderm.

To better understand the interaction mechanisms of plant surfaces with polar organic compounds, sorption of 4-chlorophenol, 2,4-dichlorophenol, and 2,4,6-trichlorophenol by fruit cuticles (i.e., tomato, apple, and pepper), and potato tuber periderm were investigated. The roles of cuticular components (waxes, cutin, cutan and sugar) on sorption of chlorophenols are quantitatively compared. Cutin and waxes govern the sorption capacity of bulk apple cuticle by hydrophobic interactions. Potato periderm with highest sugar content exhibits the lowest sorption capability for the chlorophenols. With the increase of hydrophobicity (i.e., Kow ) of sorbate, the relative contribution of lipophilic components (wax, cutin and cutan) on total sorption increases, however, the ratios of Koc to Kow decreases due to increasing ionization degree of sorbates.