Colobronchial fistula: the pathogenesis, clinical presentations, diagnosis and treatment

BACKGROUND

Colobronchial fistula (CBF) is rare and easy to be delayed in clinic. There is no systemic study about this disease. The pathogenesis, clinical presentations, diagnosis and treatment of CBF were analyzed in this study.

METHODS

The clinical data from 37 cases of CBF, which included one case in our institute and the other 36 cases in literature from January 1960 to August 2016, were reviewed and analyzed. The etiology, clinical presentations, diagnostic and therapeutic methods, and outcomes were summarized.

RESULTS

The causes of CBF included Crohn's disease, postoperative intraperitoneal adhesion, diaphragmatic hernia, pulmonary infection or abscess, colonic malignancy, colonic interposition, radiation, hyperthermic intraperitoneal chemotherapy (HIPEC), diaphragmatic mesh repair, pulmonary tuberculosis and pyonephrosis. Based on the anatomical location and the causes of fistula, CBF were divided into four types: type I, CBF secondary to the adhesion among colon, diaphragm and lung; type II, CBF secondary to diaphragmatic hernia; type III, CBF secondary to sub diaphragmatic abscess or emphysema; type VI, CBF secondary to colon interposition. The characteristic clinical presentations of CBF was productive cough with foul smelling sputum (78.38%), most of the patients were finally confirmed the diagnosis by barium enema or water-soluble contrast enema study (67.57%) and computer tomography (CT) scan/with multiplanar reconstruction (16.22%); 35 cases (94.59%) accepted the surgical treatment. Among 31 patients with recorded follow-up data, 26 patients recovered unevenly, but 5 patients died in 1 month after treatment.

CONCLUSIONS

CBF is a rare but can not be ignored disease. Anything which may induce the direct or indirect connection between colon and lung tissue may result in CBF. Productive cough with foul smelling sputum is the characteristic symptom. Radiological investigations such as barium enema and/or CT scan with multiplanar reconstruction are valuable for the confirmation of CBF. Surgery based on the etiology is the foundation of treatment.

Limbic Encephalitis Associated with Anti-γ-aminobutyric Acid B Receptor Antibodies: A Case Series from China

Background:

Autoimmune encephalitis associated with antibodies against γ-aminobutyric acid B receptor (GABA_B R) in patients with limbic encephalitis (LE) was first described in 2010. We present a series of Han Chinese patients for further clinical refinement.

Methods:

Serum and cerebrospinal fluid (CSF) samples from patients referred to the program of encephalitis and paraneoplastic syndrome of Peking Union Medical College Hospital were tested with indirect immunofluorescence. Clinical information of patients with anti-GABA_B R antibody positivity was retrospectively reviewed, and descriptive statistical analysis was performed.

Results:

All eighteen anti-GABA_B R antibody-positive cases had limbic syndromes, and electroencephalogram (EEG) or neuroimaging evidence fulfilled the diagnostic criteria of LE. Four patients had additional antibodies against Hu in serum and one had anti-N-methyl-d-aspartate receptor antibody in both sera and CSF. Seventeen (17/18) patients presented with new-onset refractory seizure or status epileptics. Twelve (12/18) patients had memory deficits, 11 (11/18) patients had personality change, 7 (7/18) patients had disturbance of consciousness, and 3 (3/18) patients showed cerebellar dysfunction. One patient with LE had progressive motor and sensory polyneuropathy. Lung cancer was detected in 6 (6/18) patients. Ten (10/18) patients showed abnormality in bilateral or unilateral mediotemporal region on magnetic resonance imaging. Ten (10/18) patients had temporal lobe epileptic activity with or without general slowing on EEG. Seventeen patients received immunotherapy and 15 of them showed neurological improvement. Four patients with lung cancer died within 1–12 months due to neoplastic complications.

Conclusions:

Our study demonstrates that most Han Chinese patients with anti-GABA_B R antibody-associated LE have prominent refractory epilepsy and show neurological improvement on immunotherapy. Patients with underlying lung tumor have a relatively poor prognosis. Testing for anti-GABA_B R antibodies is necessary for patients with possible LE or new-onset epilepsy with unknown etiology.

Fate and transport of polychlorinated biphenyls (PCBs) in the River Thames catchment - Insights from a coupled multimedia fate and hydrobiogeochemical transport model

The fate of persistent organic pollutants (POPs) in riverine environments is strongly influenced by hydrology (including flooding) and fluxes of sediments and organic carbon. Coupling multimedia fate models (MMFMs) and hydrobiogeochemical transport models offers unique opportunities for understanding the environmental behaviour of POPs. While MMFMs are widely used for simulating the fate and transport of legacy and emerging pollutants, they use greatly simplified representations of climate, hydrology and biogeochemical processes. Using additional information about weather, river flows and water chemistry in hydrobiogeochemical transport models can lead to new insights about POP behaviour in rivers. As most riverine POPs are associated with suspended sediments (SS) or dissolved organic carbon (DOC), coupled models simulating SS and DOC can provide additional insights about POPs behaviour. Coupled simulations of river flow, DOC, SS and POP dynamics offer the possibility of improved predictions of contaminant fate and fluxes by leveraging the additional information in routine water quality time series. Here, we present an application of a daily time step dynamic coupled multimedia fate and hydrobiogeochemical transport model (The Integrated Catchment (INCA) Contaminants model) to simulate the behaviour of selected PCB congeners in the River Thames (UK). This is a follow-up to an earlier study where a Level III fugacity model was used to simulate PCB behaviour in the Thames. While coupled models are more complex to apply, we show that they can lead to much better representation of POPs dynamics. The present study shows the importance of accurate sediment and organic carbon simulations to successfully predict riverine PCB transport. Furthermore, it demonstrates the important impact of short-term weather variation on PCB movement through the environment. Specifically, it shows the consequences of the severe flooding, which occurred in early 2014 on sediment PCB concentrations in the River Thames.

An Efficient Fine-to-Coarse Wayfinding Strategy for Robot Navigation in Regionalized Environments

This paper proposes an efficient wayfinding strategy for robot navigation in regionalized environments by designing a regionalized spatial knowledge model (RSK model) and a region-based wayfinding algorithm, i.e., a fine-to-coarse A* (FTC-A*) search algorithm. First, the RSK model, which imitates the representation of environments in the human brain, is presented to describe the search environments. The environments that are divided into regions are represented by a hierarchical nested structure where small regions are grouped together to form superordinate regions. Second, on the basis of the RSK model, an FTC-A* search algorithm is developed to plan the fine-to-coarse route. By making a fine planning to robot surroundings in vicinity, but a coarse planning to that at the distance, the FTC-A* algorithm can effectively reduce computational complexity, so as to enhance the efficiency of route search, and meanwhile makes robots to react quickly to user's commands, especially in large-scale environments. Finally, four exhaustive simulations and a physical experiment have been carried out to illustrate the feasibility and effectiveness of the proposed wayfinding strategy.

New Insights Into Cellular Stress Responses to Environmental Metal Toxicants

Exposures to metal toxicants in the environment disrupt normal physiological functions and have been linked to the development of a myriad of human diseases. While the molecular and cellular mechanisms underlying metal toxicities remain to be fully understood, it is well appreciated that metal toxicants induce cellular stresses and that how cells respond to the stresses plays an important role in metal toxicity. In this review, we focus on how metal exposures induce stresses in the endoplasmic reticulum (ER) to elicit the unfolded protein response (UPR). We document the emerging evidence that induction of ER stress and UPR in the development of human diseases is associated with metal exposures. We also discuss the role of the interplay between ER stress and oxidative stress in metal toxicity. Finally, we review recent advances in functional genomics approaches and discuss how applications of these new tools could help elucidate the molecular mechanisms underlying cellular stresses induced by environmental metal toxicants.

Clinical Charateristics and Outcome of Pyogenic Liver Abscess with Different Size: 15-Year Experience from a Single Center

The standard therapeutic protocols of pyogenic liver abscess (PLA) have not been well established yet. We investigated the clinical characteristics, disease progression, choices of treatments and outcomes of PLA with different size. 410 cases of patients with PLA were enrolled retrospectively from 2000 to 2014, and were grouped as small abscess (≤5 cm, n = 125), large abscess (5 cm to 10 cm, n = 218) and giant abscess (>10 cm, n = 36). The most common bacteria were Klebsiella pneumonia (22%) and Escherichia coli (11%) by pus culture, and Escherichia coli (36.7%), gram-positive coccus,(36.7%) and Klebsiella pneumonia (33.3%) by blood culture. 115 patients (28.0%) received antibiotics treatment alone, 161 patients (39.3%) received percutaneous drainage (PD) and 134 patients (32.7%) underwent surgical incision and drainage (SD). The size of abscess was correlated with leukocytes increase, albumin decrease, and time duration for body temperature normalization (all p < 0.05). Antibiotics treatment alone, PD and SD was mainly used in patients with small abscess (42.4%), large abscess (44.0%) and giant abscess (47.2%), respectively. For patients with giant abscess, SD group (n = 17) had higher morbidity than PD group (n = 14) (76.4% vs. 35.7%, p = 0.022). PD might achieve the same curative rate as SD in giant abscess, but with less trauma, lower morbidity and shorter hospital stay.

A path planning strategy for searching the most reliable path in uncertain environments

A path planning method for searching the most reliable path in uncertain environments is proposed in this article. When a robot chases a target in a semi-structured workspace with hazards and uncertainty, which path it takes is of great matter as different paths can lead to diverse risks. To “enlighten” the robot on a wiser choice, a reliability-based topological map is built, in which it is possible to add uncertainty information such as threats and road condition to topological nodes. With this map, the robot is possible to minimize risks in carrying out a target search task. Further simulation and physical-world experiments indicate that the most reliable path method generates a path a bit longer, following which the robot encounters less risks.

Improved method to fully compensate the spatial phase nonuniformity of LCoS devices with a Fizeau interferometer

Liquid crystal on silicon (LCoS) devices usually show spatial phase nonuniformity (SPNU) in applications of phase modulation, which comprises the phase retardance nonuniformity (PRNU) as a function of the applied voltage and inherent wavefront distortion (WFD) introduced by the device itself. We propose a multipoint calibration method utilizing a Fizeau interferometer to compensate SPNU of the device. Calibration of PRNU is realized by defining a grid of 3×6 cells onto the aperture and then calculating phase retardance of each cell versus a gradient gray pattern. With designing an adjusted gray pattern calculated by the calibrated multipoint phase retardance function, compensation of inherent WFD is achieved. The peak-to-valley (PV) value of the residual WFD compensated by the multipoint calibration method is significantly reduced from 2.5λ to 0.140λ, while the PV value of the residual WFD after global calibration is reduced to 0.364λ. Experimental results of the generated finite-energy 2D Airy beams in Fourier space demonstrate the effectiveness of this multipoint calibration method.

Silk-Hydroxyapatite Nanoscale Scaffolds with Programmable Growth Factor Delivery for Bone Repair

Osteoinductive biomaterials are attractive for repairing a variety of bone defects, and biomimetic strategies are useful toward developing bone scaffolds with such capacity. Here, a multiple biomimetic design was developed to improve the osteogenesis capacity of composite scaffolds consisting of hydroxyapatite nanoparticles (HA) and silk fibroin (SF). SF nanofibers and water-dispersible HA nanoparticles were blended to prepare the nanoscaled composite scaffolds with a uniform distribution of HA with a high HA content (40%), imitating the extracellular matrix (ECM) of bone. Bone morphogenetic protein-2 (BMP-2) was loaded in the SF scaffolds and HA to tune BMP-2 release. In vitro studies showed the preservation of BMP-2 bioactivity in the composite scaffolds, and programmable sustained release was achieved through adjusting the ratio of BMP-2 loaded on SF and HA. In vitro and in vivo osteogenesis studies demonstrated that the composite scaffolds showed improved osteogenesis capacity under suitable BMP-2 release conditions, significantly better than that of BMP-2 loaded SF-HA composite scaffolds reported previously. Therefore, these biomimetic SF-HA nanoscaled scaffolds with tunable BMP-2 delivery provide preferable microenvironments for bone regeneration.

The optimal dose of dexmedetomidine added to an sufentanil-based analgesic regimen for postoperative pain control in spine surgery: A probit analysis study

Postoperative spinal patients remain a challenge for provision of postoperative analgesia. Patient-controlled intravenous analgesia (PCIA) is a major method in reducing the severe pain after the surgery in our institution, but some adverse effects prevent the use of adequate dosage opioids.This study was determined using the probit analysis to investigate the optimal dose of dexmedetomidine (DEX) infusion for postoperative analgesia combined with sufentanil (SUF) in spine surgery.The dose of DEX needed to produce satisfactory analgesia conditions following combination of 3.0 μg/kg SUF in PCIA pump, which was diluted to 250 mL with a 4 mL/h as background infusion. Patients were recruited with age 35 to 65 years. The satisfactory criteria of postoperative analgesia were determined with a average satisfaction level of pain control, sedation, self-satisfaction, and adverse effects, among others. The dose of DEX was determined using the modified Dixon's up-and-down method (0.5 μg/kg as a step size). The first patient was test at 3.0 μg/kg DEX. The patient was assessed at 6, 12, 36 hours, and termination of PCIA following the continuous infusion of DEX-SUF mixture in PCIA after surgery.Twenty-five patients were enrolled by predetermined criteria. The optimal dose of DEX required for satisfactory analgesic was 4.33 (SD, 0.38) μg/kg combined with 3.0 μg/kg SUF via a PCIA volume of 250 mL by background infusion of 4 mL/h. Using probit analysis, the ED50 of DEX was 4.12 μg/kg (95% confidence limits 3.74-4.52 μg/kg) for satisfactory postoperative analgesic in spine surgery, the ED95 of DEX was 4.85 μg/kg (95% confidence limits 4.48-7.13 μg/kg). There was no report of somnolence or respiratory depression, relevant bradycardia or hypotension, or over sedation in this study.The optimal dose of DEX was 4.33 (0.38) μg/kg combined with 3.0 μg/kg SUF diluted to 250 mL with a background infusion of 4 mL/h for satisfactory analgesic after spine surgery. From probit analysis, ED50 and ED95 of DEX were 4.12 μg/kg (95% confidence limits 3.74-4.52 μg/kg) and 4.85 μg.kg (95% confidence limits 4.48-7.13 μg/kg), respectively.

Performance of obesity indices for screening elevated blood pressure in pediatric population: Systematic review and meta-analysis

BACKGROUND

Hypertension is closely related with obesity in pediatric population. Obesity indices were used for screening elevated blood pressure (BP) in children and adolescents. The present study was to perform a meta-analysis to assess the performance of obesity indices, body mass index (BMI), waist circumference (WC), and waist-to-height ratio (WHtR), for identifying elevated BP in children and adolescents.

METHODS

Data sources were PubMed, EMBASE, Web of Science, Cochrane, and SCOPUS up to May 2016. Studies providing measures of diagnostic performance of obesity indices and using age-, sex-, and height-specific BP 95% as reference standard (the definition of United State Fourth Report) were included. We extracted available data on true-positive, false-positive, true-negative, and false-negative to construct a 2 × 2 contingency table and computed the pooled summary statistics for the sensitivities and specificities to estimate the diagnostic performance.

RESULTS

Nine eligible studies that evaluated 25,424 children and adolescents aged 6 to 18 years were included in the meta-analysis. The pooled sensitivities were 42% (BMI), 42% (WC), and 43% (WHtR). The pooled specificities were 80% (BMI), 75% (WC), and 77% (WHtR). The areas under the curve (AUCs) of obesity indices were 0.7780 (BMI), 0.7181 (WC), and 0.6697 (WHtR), respectively. In this meta-analysis, the BP measurements were based on 3 visits in only 1 study. The prevalence of hypertension may be overestimated in these studies.

CONCLUSIONS

The present meta-analysis showed that the performance of obesity indices for identifying elevated BP was poor. Our findings do not support the performance of WC and WHtR is superior to BMI to help identify children with elevated BP.

Modeling Alkaline Phosphatase Inactivation in Bovine Milk During High-Temperature Short-Time Pasteurization

Alkaline phosphatase (AP) is used as the indicator enzyme for proper pasteurization of bovine milk. Predictive modeling of AP inactivation during high-temperature short-time (HTST) pasteurization would support regulations; thus ensuring the safety of heat treated milk. Activation energy (Ea) of AP in milk was measured experimentally using the capillary tube method, and Ea was found to be 429252 J/mol. The Ea was used to develop a nonlinear model to describe the thermal inactivation of milk in a small-scale HTST pasteurizer with a plate heat exchanger. Integrated pasteurization effect (PE) was obtained at different holding temperatures (62–72°C) and holding times (3–25 s), by converting times at different temperatures in various sections of the pasteurizer to the equivalent time at the reference temperature (72°C). A nonlinear function was developed to relate the log(% residual AP activity) to PE. The r2 varied from 0.7488 to 0.8311. The validation trial indicated that the model could predict AP activity accurately for the% residual AP activity >1%.

MiR-200c promotes bladder cancer cell migration and invasion by directly targeting RECK

Background

Increasing evidence suggests that the dysregulation of certain microRNAs plays an important role in tumorigenesis and metastasis. MiR-200c exhibits a disordered expression in many tumors and presents dual roles in bladder cancer (BC). Therefore, the definite role of miR-200c in BC needs to be investigated further.

Materials and methods

Quantitative reverse transcription polymerase chain reaction was used to assess miR-200c expression. Cell invasion and migration were evaluated using wound healing and transwell assays. The luciferase reporter assay was used to identify the direct target of miR-200c. The expression of reversion-inducing cysteine-rich protein with kazal motifs (RECK) in BC tissues and adjacent nontumor tissues, as well as in BC cell lines, was detected through quantitative reverse transcription polymerase chain reaction, Western blot assay, and immunohistochemistry.

Results

The miR-200c expression was significantly upregulated in the BC tissues compared with the adjacent nontumor tissues. The downregulation of miR-200c significantly inhibited cell migration and invasion in the BC cell lines. The luciferase reporter assay showed that RECK was a direct target of miR-200c. The knockdown of RECK in the BC cell lines treated with anti-miR-200c elevated the previously attenuated cell migration and invasion.

Conclusion

Our findings indicated that miR-200c functions as oncogenes in BC and may provide a novel therapeutic strategy for the treatment of BC.

Assessment of epidermal growth factor receptor mutation/copy number and K-ras mutation in esophageal cancer

BACKGROUND

The molecular status of epidermal growth factor receptor (EGFR) in esophageal cancer has not been well elucidated. The purpose of the study was to investigate the prevalence of EGFR and K-ras mutation, and EGFR gene copy number status as well as its association with clinicopathologic characteristics, and also to identify the prognostic value of EGFR gene copy number in esophageal cancer.

METHODS

EGFR mutation in exon 19/exon 21 and K-ras mutation in codon 12/codon 13 were detected by real-time PCR method, while EGFR gene copy number status was analyzed by fluorescent in situ hybridization (FISH). EGFR gene amplification and high polysomy were defined as high EGFR gene copy number status (FISH-positive), and all else were defined as low EGFR gene copy number status (FISH-negative). The relationship between EGFR gene copy number status and clinicpathologic characteristics was analyzed. Kaplan-Meier method and Cox proportional hazards regression model were employed to evaluate the effects of EGFR gene copy number status on the patients' survival.

RESULTS

A total of 57 esophageal squamous cell carcinoma (ESCC) patients and 9 esophageal adenocarcinoma (EADC) patients were enrolled in the study. EGFR mutation was identified in one patient who was diagnosed as ESCC with stage IIIC disease. K-ras mutation was identified in one patient who was diagnosed as EADC. In all, 34 of 66 (51.5%) samples were detected as FISH-positive, which includes 30 ESCC and 4 EADC tumor samples. The correlation analysis showed that FISH-positive was significantly associated with the tumor stage (P=0.019) and lymph node metastasis (P=0.005) in esophageal cancer patients, and FISH-positive was also significantly associated with the tumor stage (P=0.007) and lymph node metastasis (P=0.008) in ESCC patients. Cox regression analysis showed that high EGFR gene copy number was not a significant predictor of a poor outcome for esophageal cancer patients (P=0.251) or for ESCC patients (P=0.092), but esophageal cancer patients or ESCC patients with low EGFR gene copy number may have longer survival than those with high EGFR gene copy number according to the survival curve trends.

CONCLUSIONS

The results indicated that EGFR or K-ras mutation was rare in esophageal cancer, but high EGFR gene copy number is frequent, and correlated with advanced pathologic stage and more number of the metastatic regional lymph nodes, especially in ESCC. In addition, high EGFR gene copy number is likely to have a deleterious effect on prognosis of esophageal cancer patients or ESCC patients, although no statistical significance was reached in the study.

Anticancer effect of deoxypodophyllotoxin induces apoptosis of human prostate cancer cells

Deoxypodophyllotoxin (DPPT) is extracted and separated from citrus-related plants, including Podophyllum (P.) peltatum, P. pleianthum, P. emodi (also called P. hexandrum) and Diphylleia grayi. DPPT has significant antitumor and antiviral activity. However, due to its strong toxicity and side effects, its use is limited in practical applications. The in vitro antitumor efficacy of DPPT on human prostate cancer (PCa) cells remains to be determined. The present study investigated the anticancer effect of DPPT on human PCa cells and its potential mechanism. The data revealed that DPPT markedly reduced cell proliferation and activated the caspase-3 expression level by an increase in apoptotic cell death in DU-145 cells. In addition, treatment with DPPT markedly downregulated the levels of phosphorylated Akt and activated the p53/B-cell lymphoma 2 associated X protein (Bax)/phosphatase and tensin homolog (PTEN) signaling pathway in DU-145 cells, suggesting that caspase-mediated pathways were involved in DPPT-induced apoptosis. The present study suggested the role of DPPT as a novel chemotherapeutic drug for human PCa, which may function through the Akt/p53/Bax/PTEN signaling pathway.

AAV-mediated transduction and targeting of retinal bipolar cells with improved mGluR6 promoters in rodents and primates

Adeno-associated virus (AAV) vectors have been a powerful gene delivery vehicle to the retina for basic research and gene therapy. For many of these applications, achieving cell type-specific targeting and high transduction efficiency is desired. Recently, there has been increasing interest in AAV-mediated gene targeting to specific retinal bipolar cell types. A 200-bp enhancer in combination with a basal SV40 promoter has been commonly used to target transgenes into ON-type bipolar cells. In the current study, we searched for additional cis-regulatory elements in the mGluR6 gene for improving AAV-mediated transduction efficiency into retinal bipolar cells. Our results showed that the combination of the endogenous mGluR6 promoter with additional enhancers in the introns of the mGluR6 gene markedly enhanced AAV transduction efficiency as well as made the targeting more selective for rod bipolar cells in mice. Furthermore, the AAV vectors with the improved promoter could target to ON bipolar cells with robust transduction efficiency in the parafovea and the far peripheral retina of marmoset monkeys. The improved mGluR6 promoter constructs could provide a valuable tool for genetic manipulation in rod bipolar cells in mice and facilitate clinical applications for ON bipolar cell-based gene therapies.

Value of intravoxel incoherent motion and dynamic contrast-enhanced MRI for predicting the early and short-term responses to chemoradiotherapy in nasopharyngeal carcinoma

The aim of the study was to investigate the value of intravoxel incoherent motion diffusion-weighted magnetic resonance imaging (IVIM-DWI) and dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) in predicting the early and short-term responses to chemoradiotherapy (CRT) in patients with nasopharyngeal carcinoma (NPC).Forty-three NPC patients underwent IVIM-DWI and DCE-MRI at baseline (pretreatment) and after the first cycle of induction chemotherapy (posttreatment). Based on whether locoregional lesions were identified, patients were divided into the residual and nonresidual groups at the end of CRT and into the good-responder and poor-responder groups 6 months after the end of CRT. The pretreatment and posttreatment IVIM-DWI parameters (ADC, D, D*, and f) and DCE-MRI parameters (K, Kep, and Ve) values and their percentage changes (Δ%) were compared between the residual and nonresidual groups and between the good-responder and poor-responder groups.None of perfusion-related parametric values derived from either DCE-MRI or IVIM-DWI showed significant differences either between the residual and nonresidual groups or between the good-responder and poor-responder groups. The nonresidual group exhibited lower pre-ADC, lower pre-D, and higher Δ%D values than did the residual group (all P <0.05). The good-responder group had lower pre-D and pre-ADC values than did the poor-responder group (both P <0.05). Based on receiver operating characteristic (ROC) curve analysis, pre-D had the highest area under the curve in predicting both the early and short-term responses to CRT for NPC patients (0.817 and 0.854, respectively).IVIM-DWI is more valuable than DCE-MRI in predicting the early and short-term response to CRT for NPC, and furthermore diffusion-related IVIM-DWI parameters (pre-ADC, pre-D, and Δ%D) are more powerful than perfusion-related parameters derived from both IVIM-DWI and DCE-MRI.

Ecotoxicological evaluation of low-concentration bisphenol A exposure on the soil nematode Caenorhabditis elegans and intrinsic mechanisms of stress response in vivo

As a representative species of nematodes, Caenorhabditis elegans is an attractive animal model for evaluating ecotoxicological effects and intrinsic mechanisms of the stress response in vivo. To acquire a better knowledge of environmental effects of bisphenol A (BPA), ecotoxicological evaluations were conducted using C. elegans on the physiological (growth, locomotion behaviors, and reproduction), biochemical (lipofuscin accumulation, reactive oxygen species production, and cell apoptosis), and molecular (stress-related gene expression) responses. Nematodes were exposed to BPA (0.001-10 µM) in 2 assay systems (L4 larvae for 24 h and L1 larvae for 72 h). Exposure to BPA could significantly (p < 0.05) alter body length, locomotion behaviors, brood size, cell apoptosis, and selected stress-related gene expression. At the physiological level, BPA exerted adverse effects on nematodes at the microgram per liter level in both assay systems, with head thrashes as the most sensitive endpoint. At the biochemical level, apoptosis degree showed increases at concentrations above 0.1 µM in both assay systems. At the molecular level, BPA induced increases in selected stress-related gene expression, even at the lowest tested concentration. In addition, BPA-induced cell apoptosis was suggested as a potential mode of action, resulting in adverse physiological effects. Therefore, BPA exposure was speculated to impose developmental, reproductive, and neurobehavioral toxicities on C. elegans and caused variations of stress-related gene expression. Environ Toxicol Chem 2016;35:2041-2047. © 2016 SETAC.