Effect of convection and B1 inhomogeneity on singlet relaxation experiments

Nuclear spin singlet lifetimes can often exceed the T₁ length scales by a large factor. This property makes them suitable for polarization storage. The measurement of such long lifetimes itself can become challenging due to the influence of even very weak relaxation mechanisms. Here we show that a judicious choice of the singlet-to-triplet conversion method is highly important in order to achieve reliable singlet relaxation measurements. In particular, we identify thermal convection, in connection with B₁ field gradients, asa significant apparent decay mechanism, which limits the ability to measure the true singlet state lifetimes. Highly B₁-compensated broadband singlet excitation/detection sequences are shown to minimize the influence of macroscopic molecular motion and B₁ inhomogeneity.

Tissue-specific distributions of inorganic arsenic and its methylated metabolites, especially in cerebral cortex, cerebellum and hippocampus of mice after a single oral administration of arsenite

Groundwater contaminated with inorganic arsenic (iAs) is the main source of human exposure to arsenic and generates a global health issue. In this study, the urinary excretion, as well as the time-course distributions of various arsenic species in murine tissues, especially in different brain regions were determined after a single oral administration of 2.5, 5, 10 and 20mg/kg sodium arsenite (NaAsO₂). Our data showed that the peak times of urinary, hepatic and nephritic total arsenic (TAs) were happened at about 1h, then TAs levels decreased gradually and almost could not be observed after 72h. On contrast, the time course of TAs in lung, urinary bladder and different brain regions exhibited an obvious process of accumulation and elimination,and the peak times were nearly at 6h to 9h. TAs levels of 10 and 20mg/kg NaAsO₂ groups were significantly higher than 2.5 and 5mg/kg groups, and the amounts of TAs in 5mg/kg groups were in the order of liver>lung>kidney>urinary bladder>hippocampus>cerebral cortex>cerebellum. In addition, iAs was the most abundant species in liver and kidney, while lung and urinary bladder accumulated the highest concentrations of dimethylated arsenicals (DMA). What's more, the distributions of arsenic species were not homogeneous among different brain regions, as DMA was the sole species in cerebral cortex and cerebellum, while extremely high concentrations and percentages of monomethylated arsenicals (MMA) were found in hippocampus. These results demonstrated that distributions of iAs and its methylated metabolites were tissue-specific and even not homogeneous among different brain regions, which must be considered as to the tissue- and region-specific toxicity of iAs exposure. Our results thus provide useful information for clarifying and reducing the uncertainty in the risk assessment for this metalloid.

Comprehensive analysis of proton range uncertainties related to stopping-power-ratio estimation using dual-energy CT imaging

The dual-energy CT-based (DECT) approach holds promise in reducing the overall uncertainty in proton stopping-power-ratio (SPR) estimation as compared to the conventional stoichiometric calibration approach. The objective of this study was to analyze the factors contributing to uncertainty in SPR estimation using the DECT-based approach and to derive a comprehensive estimate of the range uncertainty associated with SPR estimation in treatment planning. Two state-of-the-art DECT-based methods were selected and implemented on a Siemens SOMATOM Force DECT scanner. The uncertainties were first divided into five independent categories. The uncertainty associated with each category was estimated for lung, soft and bone tissues separately. A single composite uncertainty estimate was eventually determined for three tumor sites (lung, prostate and head-and-neck) by weighting the relative proportion of each tissue group for that specific site. The uncertainties associated with the two selected DECT methods were found to be similar, therefore the following results applied to both methods. The overall uncertainty (1σ) in SPR estimation with the DECT-based approach was estimated to be 3.8%, 1.2% and 2.0% for lung, soft and bone tissues, respectively. The dominant factor contributing to uncertainty in the DECT approach was the imaging uncertainties, followed by the DECT modeling uncertainties. Our study showed that the DECT approach can reduce the overall range uncertainty to approximately 2.2% (2σ) in clinical scenarios, in contrast to the previously reported 1%.

[Therapeutic effect of a new hybrid technique which combined laparoscopic method and abdominal repair for parastomal hernia repair]

Objective: To investigate the safety and effectiveness of a new hybrid technique which combined laparoscopic method and abdominal repair (Dual Lap) for parastomal herniarepair. Methods: The clinical and follow-up data of 27 cases who accepted Dual Lap procedure performed at Department of Hernia and Abdominal Wall Surgery, Wuhan Central Hospital, Tongji Medical College of Huazhong University from January 2010 to January 2015 were analyzed retrospectively. The data included 22 male patients and 5 female patients with mean age of 54 years. Of the patients, there were 19 cases of the left hernia and 8 cases of the right hernia, without ostomy hernia repair history. There were 4 cases of the occult hernial defects during the operation. There were 8 patients with ilealneobladder, 2 patients with ileostomyafter total colectomy for familial adenomatous polyposis, 3 patients with ileostomy and 14 patients with colostomy for ulcerative colitis. Results: All cases underwent hybrid technique successfully. The mean operation time was (108±16) minutes(ranging from 90 to 150 minutes) and the diameter of the hernial ring was (6.4±1.8)cm (ranging from 3 to 13 cm). There were no intestinal, kidney and ureteral obstructions in operations. Five cases need to use the analgesic adjuvant at 48-hour after operation. The time of postoperative defecations was (9.3±2.4) days (ranging from 7 to 16 days) and there were no intestinal leakage, local hematoma, wound infection and fat liquefaction after operations. All patients were followed up for (16.3±4.2) months (ranging from 12 to 48 months). There was no ileus, obvious seroma, hernia recurrence, chronic pain and mesh infection. Conclusion: The Dual Lap procedureis safe and effective for parastomal hernia repair with less complication.

A meta-analysis of breastfeeding and osteoporotic fracture risk in the females

Our meta-analysis included 12 studies from PubMed, Embase, and Web of Science. Finding indicated breastfeeding may well reduce the risk of osteoporotic fracture.

INTRODUCTION

Several epidemiologic studies have investigated that breastfeeding is associated with short-term bone loss in the women, but the long-term effect on osteoporotic fracture risk remains unclear. Thus, we conducted this meta-analysis to explore the potential association between breastfeeding and osteoporotic fracture risk in the females and possible dose-response relationship between them.

METHODS

We searched PubMed, Embase, and Web of Science (ISI) up to April 2016 for relevant articles associated between breastfeeding and osteoporotic fracture. Pooled relative risks (RRs) with 95 % confidence intervals (CIs) were calculated with a random-effects model. Dose-response analysis was performed by restricted cubic spline.

RESULTS

Twelve articles including 14,954 participants were identified. The pooled RRs of osteoporotic hip and forearm fracture for the highest vs lowest duration of breastfeeding were 0.84 (95 % CI 0.67-1.05), 0.72 (95 % CI 0.52-0.99), and 0.82 (95 % CI 0.56-1.19), respectively. In subgroup analysis, breastfeeding was associated with a decreased risk of osteoporotic fracture in case-control study (RR = 0.70, 95 % CI 0.49-0.99) and postmenopausal women (RR = 0.66, 95 % CI 0.47-0.93). In dose-response analysis, osteoporotic and hip fracture risk decreased by 0.9 and 1.2 % for each month increment of breastfeeding, respectively.

CONCLUSIONS

Our meta-analysis revealed that breastfeeding may well reduce the risk of osteoporotic fracture. More cohort studies with large sample sizes are needed to confirm the conclusion.

Myostatin in black Muscovy duck (Cairina moschata): full-length cDNA cloning and age-dependent mRNA expression compared with IGF-I

Insulin-like growth factor-I (IGF-I) and myostatin (MSTN) are a pair of critical positive and negative growth regulators. The aim of the current study was to examine the age-dependent and muscle-specific expression of IGF-I and MSTN mRNAs in black Muscovy ducks in order to understand their roles in regulating the postnatal muscle growth of domestic ducks. The full-length cDNA of the black Muscovy duck MSTN gene was cloned and the age-dependent mRNA expression profile was compared with that of the IGF-I mRNA in skeletal muscles. The cDNA sequence of the MSTN gene was 1128 bp in length and encodes 375 amino acids, with more than 94.9% homology with poultry MSTN genes, and 83.0-92.0% homology with that of human and mammals (accession: KR006339.1). The IGF-I and MSTN mRNA expression exhibited opposite trends in age-dependency and in different muscles: IGF-I mRNA level was high in the early postnatal stage and low in the late mature stage, corresponding positively to growth; while the MSTN mRNA was low in the early stage, increased gradually and reached the highest level in mature muscles, and was negatively related to muscle growth. In the breast muscles, IGF-I mRNA was much higher than in the leg muscles; the opposite effect was seen in MSTN mRNA. These data suggest that the relative expression levels of IGF-I and MSTN are essential determinants in the temporal and muscle-specific regulation of postnatal skeletal muscle growth in Muscovy duck and possibly in other poultry species as well.

In vivo fluorescence imaging of hepatocellular carcinoma xenograft using near-infrared labeled epidermal growth factor receptor (EGFR) peptide

Minimally-invasive surgery of hepatocellular carcinoma (HCC) can be limited by poor tumor visualization with white light. We demonstrate systemic administration of a Cy5.5-labeled peptide specific for epidermal growth factor receptor (EGFR) to target HCC in vivo in a mouse xenograft model. We attached a compact imaging module to the proximal end of a medical laparoscope to collect near-infrared fluorescence and reflectance images concurrently at 15 frames/sec. We measured a mean target-to-background ratio of 2.99 ± 0.22 from 13 surgically exposed subcutaneous human HCC tumors in vivo in 5 mice. This integrated imaging methodology is promising to guide laparoscopic resection of HCC.

High preoperative and postoperative levels of carcinoembryonic antigen and CYFRA 21-1 indicate poor prognosis in patients with pathological Stage I nonsmall cell lung cancer

BACKGROUND

Serum carcinoembryonic antigen (CEA) and the soluble fragment of cytokeratin 19 (CYFRA 21-1) are supposed to have a prognostic role in patients with nonsmall cell lung cancer (NSCLC) after surgery, but it has not been used as an adjunct to the tumor-node-metastasis (TNM) staging system to provide therapy options for patients with pathological Stage I NSCLC. This study was designed to investigate the effect of serum levels of CEA and CYFRA 21-1 before and after surgery on the prognosis of patients with Stage I NSCLC.

MATERIALS AND METHODS

A retrospective review was performed regarding the medical records and follow-ups of 169 patients with Stage I NSCLC before and after surgery. The patients were divided into three groups based on levels of serum CEA and CYFRA 21-1 before and after surgery: (1) continuously normal-level groups (CEA [NN] and CYFRA 21-1 [NN] groups); (2) declined to normal-level groups (CEA [HN] and CYFRA 21-1 [HN] groups); and (3) continuously high-level groups (CEA [HH] and CYFRA 21-1 [HH] groups). Survival analysis was conducted using the Kaplan-Meier method for each group. The Chi-square or Fisher exact test was employed to compare clinical and pathologic factors at the level of P < 0.05. The prognostic factor was evaluated by the Cox proportional hazards model.

RESULTS

Compared with the continuously normal-level groups, the CEA [HN] group was significantly correlated to tumor size (P = 0.011), and the CYFRA 21-1 [HN] group was significantly correlated to tumor type and pathological TNM in addition to tumor size. Five-year survivals were significantly lower (P = 0.004) in the CEA [HH] group (67.3%) and the CEA [HN] group (86.5%) than in the CEA [NN] group (85.7%) and were significantly lower (P < 0.001) in the CYFRA 21-1 [HH] group (47.2%) and the CYFRA 21-1 [HN] group (70.1%) than in the CYFRA 21-1 [NN] group (90.1%). Multivariate analysis demonstrated that tumor size (21-50 mm), CEA [HH], and CYFRA 21-1 [HH] were independent unfavorable prognostic factors for overall survival (OS), whereas tumor size (21-50 mm), CEA [HH], CYFRA 21-1 [HN], and CYFRA 21-1 [HH] were independent significant prognostic factors for progression-free survival (PFS).

CONCLUSION

Patients with a persistently high serum CEA or CYFRA 21-1 before and after surgery had shortest OS and PFS. These patients had worst prognosis. Adjuvant chemotherapy was likely to improve survival for these patients.

[Study on the threshold of HIV-1 drug resistance in Dehong prefecture of Yunnan province in 2014]

OBJECTIVE

To study the HIV-1 genotypes and transmitted drug resistance (TDR) in Dehong prefecture of Yunnan province in 2014.

METHODS

A total of 70 plasma samples of recently reported HIV-infected individuals between 16 and 25 years old were collected in Dehong prefecture from January to August 2014. Among them, 58 samples which met the criterion of HIV drug resistance threshold survey (HIVDR-TS) were subjected to genetic drug resistance detection.

RESULTS

50 plasma samples were successfully sequenced and analyzed. Among them, 34.0% were Chinese and 66.0% were Burmese. Based on pol sequences, all the identified HIV genotypes would include CRF01_AE (28.0%), subtype C(20.0%), URF(20.0% ), CRF62_BC(10.0% ), CRF08_BC(8.0% ), CRF07_BC (4.0%), CRF64_BC(4.0%), subtype B(4.0%) and CRF55_01B(2.0%). One drug, which resistant mutation to proteinase inhibitors had been detected in one sequence. Based on the statistical method of HIVDR-TS, the prevalence of transmitted HIV-1 drug resistance was adjusted as <5%.

CONCLUSION

The proportion of Burmese was relatively higher among those newly reported HIV-infected individuals aged 16 to 25 in Dehong. We noticed that the novel circulating recombinant forms began to function. However, the level of transmission through HIV-1 drug resistant strains still kept low in Dehong.

Antioxidant tert-butylhydroquinone ameliorates arsenic-induced intracellular damages and apoptosis through induction of Nrf2-dependent antioxidant responses as well as stabilization of anti-apoptotic factor Bcl-2 in human keratinocytes

Human skin is a known target site of inorganic arsenic with effects ranging from hyperkeratosis to dermal malignancies. Tert-butylhydroquinone (tBHQ), approved food-grade phenolic antioxidant, is demonstrated to induce remarkable antioxidant activity in a variety of cells and tissues. The present study aimed at the protective effects of tBHQ on arsenic-induced cytotoxicity and apoptosis in human keratinocytes. Our results demonstrated that tBHQ antagonized arsenic-induced decrease of cell viability, generation of reactive oxygen species (ROS) and lipid peroxidation, as well as reduction of antioxidative enzymes superoxide dismutase (SOD) and catalase (CAT) activities. We also found that tBHQ relieved the G2/M phase arrest by arsenic exposure, which was associated with altering the expression of cell cycle regulators cyclin D1 and CDK4. tBHQ treatment further reduced the numbers of arsenic-induced mitochondrial-mediated apoptotic cells, which occurred concomitantly with the effective recovery of mitochondrial membrane potential (ΔΨm) depolarization, the release of cytochrome c releasing from the mitochondrial as well as the survival signal related factor caspase 3 activation. Our experiments then confirmed that tBHQ activated nuclear factor E2-related factor 2 (NRF2) pathway by increasing NRF2 protein in both nucleus and cytoplasm and upregulating NRF2 downstream targets

NAD(P)H

quinine oxidoreductase 1 (NQO1) and heme oxygenase-1 (HO-1). More interestingly, arsenic-induced decrease of anti-apoptotic factor B-cell lymphoma-2 (Bcl-2) and increase of pro-apoptotic factor Bcl-2-associated X protein (Bax) could all be reversed by tBHQ pretreatment. These results suggested together that tBHQ could ameliorate arsenic-induced cytotoxicity and apoptosis, which might be linked with the induction of Nrf2-dependent antioxidant responses as well as stabilization of anti-apoptotic factor Bcl-2 in human keratinocytes.

Abstract P3-07-49: Residual cancer burden (RCB) with veliparib/carboplatin in the I-SPY2 trial

Background: I-SPY2 is a multicenter phase 2 trial in high risk stage II/III breast cancer (BC) using adaptive randomization within biomarker subtypes to evaluate novel agents added to standard neoadjuvant chemotherapy. The first regimen to graduate based on the predicted probability of a higher pCR rate within predefined subsets was veliparib/carboplatin + paclitaxel (VC+T→AC vs T→AC) in triple negative BC (TNBC). In TNBC the residual cancer burden (RCB) is prognostic, whether as a continuous index or grouped into classes, with pCR (RCB-0) and RCB-I classes having identical survival. Therefore, we evaluated the use of RCB to further discriminate between investigational and control arms.

Methods: Site pathologists reported RCB for 99% of subjects in the primary efficacy analysis based on pCR (n=114/115). We compared the distribution of RCB reported as a continuous index in each treatment-subset combination to matched concurrently randomized controls using the Wilcoxon rank sum test for RCB index, and Fisher's Exact test for RCB classes (RCB-0/I vs RCB-II/III). The statistics are descriptive rather than inferential, and given the small sample size have no claim on generalizability. We modified the Bayesian model used to compute the estimated probability of success in a future, randomized, phase 3 trial of 300 subjects, if response were defined by either pCR or RCB-I (RCB0/I), or separately if it were defined by pCR alone.

Results: VC+T→AC led to a significantly lower RCB index than T→AC in TNBC (p=0.0021), with a near-significant trend when those with pCR were excluded (p=0.06). There was no significant difference in RCB distributions in the other breast cancer subtypes treated. In TNBC, the odds ratio (OR) for achieving RCB-0/I in the VC+T→AC arm vs control was 8.2 (95% confidence interval (CI): 2.1–35), whereas the OR for achieving pCR was 4.56 (95% CI: 1.25–19.53). The simulations using response information from I-SPY2 to predict the probability of success for VC+T→AC for TNBC in a future phase 3 trial estimated this probability to be 0.99 if modeled using RCB-0/I as the response endpoint, and 0.90 if modeled using pCR as the response endpoint.

Conclusions: Use of RCB index and classes provided additional insight into the effect of adding VC to T, appearing to magnify the improved treatment response that had been observed with pCR rates in TNBC. It will be important to test in randomized trials whether a decrease in the RCB index relative to controls, and/or increased rates of RCB-0/I class, are predictive of survival benefit in TNBC.

Citation Format: Liu MC, Symmans WF, Yau C, Chen Y-Y, Rugo HS, Olopade OF, Datnow B, Chen B, Feldman M, Kallakury B, Hasteh F, Tickman R, Ritter J, Troxel M, Mhawech-Fauceglia P, Duan X, Berry D, Esserman L, DeMichele A. Residual cancer burden (RCB) with veliparib/carboplatin in the I-SPY2 trial. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P3-07-49.

Chinese military medical teams in the Ebola outbreak of Sierra Leone

The 2014-2015 Ebola virus disease (EVD) epidemic in West Africa was the largest in history. The three most affected countries, Guinea, Liberia and Sierra Leone, have faced enormous challenges in controlling transmission and providing clinical care for patients with EVD. The Chinese government, in response to the requests of the WHO and the governments of the affected countries, responded rapidly by deploying Chinese military medical teams (CMMTs) to the areas struck by the deadly epidemic. A total of three CMMTs, comprising 115 military medical professionals, were rotationally deployed to Freetown, Sierra Leone to assist with infection prevention and control, clinical care and health promotion and training. Between 1 October 2014 and 22 March 2015, the CMMTs in Sierra Leone admitted and treated a total of 773 suspected and 285 confirmed EVD cases. Among the 285 confirmed cases, 146 (51.2%) patients survived after treatment. In addition, the CMMTs maintained the record of zero infections among healthcare workers and zero cross-infections between quarantined patients. In this manuscript, we aim to give an overview of the mission, and share our best practices experience on predeployment preparedness, EVD holding and treatment centre building and EVD case management.

PDK1/Akt/PDE4D axis identified as a target for asthma remedy synergistic with β2 AR agonists by a natural agent arctigenin

BACKGROUND

Asthma is a heterogenetic disorder characterized by chronic inflammation with variable airflow obstruction and airway hyper-responsiveness. As the most potent and popular bronchodilators, β2 adrenergic receptor (β2 AR) agonists bind to the β2 ARs that are coupled via a stimulatory G protein to adenylyl cyclase, thereby improving cAMP accumulation and resulting in airway smooth muscle relaxation. We previously demonstrated arctigenin had a synergistic function with the β2 AR agonist, but the target for this remained elusive.

METHOD

Chemical proteomics capturing was used to enrich and uncover the target of arctigenin in human bronchial smooth muscle cells, and reverse docking and molecular dynamic stimulation were performed to evaluate the binding of arctigenin and its target. In vitro enzyme activities and protein levels were demonstrated with special kits and Western blotting. Finally, guinea pig tracheal muscle segregation and ex vivo function were analysed.

RESULTS

Arctigenin bound to PDK1 with an ideal binding free energy -25.45 kcal/mol and inhibited PDK1 kinase activity without changing its protein level. Additionally, arctigenin reduced PKB/Akt-induced phosphorylation of PDE4D, which was first identified in this study. Attenuation of PDE4D resulted in cAMP accumulation in human bronchial smooth muscle. The inhibition of PDK1 showed a synergistic function with β2 AR agonists and relaxed the constriction of segregated guinea pig tracheal muscle.

CONCLUSIONS

The PDK1/Akt/PDE4D axis serves as a novel asthma target, which may benefit airflow obstruction.

Isolation and characterisation of cDNA encoding a wheat heavy metal-associated isoprenylated protein involved in stress responses

In cells, metallochaperones are important proteins that safely transport metal ions. Heavy metal-associated isoprenylated plant proteins (HIPPs) are metallochaperones that contain a metal binding domain and a CaaX isoprenylation motif at the carboxy-terminal end. To investigate the roles of wheat heavy metal-associated isoprenylated plant protein (TaHIPP) genes in plant development and in stress responses, we isolated cDNA encoding the wheat TaHIPP1 gene, which contains a heavy metal-associated domain, nuclear localisation signals and an isoprenylation motif (CaaX motif). Quantitative real-time PCR analysis indicated that the TaHIPP1 gene was differentially expressed under biotic and abiotic stresses. Specifically, TaHIPP1 expression was up-regulated by ABA exposure or wounding. Additionally, TaHIPP1 over-expression in yeast (Schizosaccharomyces pombe) significantly increased the cell growth rate under Cu(2+) and high salinity stresses. The nuclear localisation of the protein was confirmed with confocal laser scanning microscopy of epidermal onion cells after particle bombardment with chimeric TaHIPP1-GFP constructs. In addition, TaHIPP1 was shown to enhance the susceptibility of wheat to Pst as determined by virus-induced gene silencing. These data indicate that TaHIPP1 is an important component in defence signalling pathways and may play a crucial role in the defence response of wheat to biotic and certain abiotic stresses.

Human cystic and alveolar echinococcosis in the Tibet Autonomous Region (TAR), China

Human cystic echinococcosis (CE) is known to be endemic in the Tibet Autonomous Region (TAR), China; however, there is relatively little data from hospital records or community prevalence studies, and the situation regarding occurrence of human alveolar echinococcosis (AE) is unclear. Here we review the available reports about human echinococcosis in the seven prefectures of TAR. In addition, two pilot studies by mass screening using ultrasound (with serology) were undertaken (2006/7) in Dangxiong County of Lhasa Prefecture (north central TAR) and Dingqing County of Changdu Prefecture (eastern TAR). In Dangxiong County a prevalence of 9.9% (55/557) for human CE was obtained but no human AE cases were detected. By contrast, in Dingqing County (N= 232 persons screened), 11 CE cases (4.7%) and 12 AE cases (5.2%) (including one mixed CE and AE case) were diagnosed by ultrasound. Hospital records and published reports indicated that CE cases were recorded in all of seven prefectures in Tibet Autonomous Region, and AE cases in four prefectures. Incidence rates of human CE were estimated to range from 1.9 to 155 per 100,000 across the seven prefectures of TAR, with a regional incidence of 45.1 per 100,000. Incidence of AE was estimated to be between 0.6 and 2.8 cases per 100,000. Overall for TAR, human AE prevalence appeared relatively low; however, the pilot mass screening in Dingqing in eastern TAR indicated that human AE disease is a potential public health problem, possibly similar to that already well described in Tibetan communities bordering TAR in north-west Sichuan and south-west Qinghai provinces.

Hepatic and Nephric NRF2 Pathway Up-Regulation, an Early Antioxidant Response, in Acute Arsenic-Exposed Mice

Inorganic arsenic (iAs), a proven human carcinogen, damages biological systems through multiple mechanisms, one of them being reactive oxygen species (ROS) production. NRF2 is a redox-sensitive transcription factor that positively regulates the genes of encoding antioxidant and detoxification enzymes to neutralize ROS. Although NRF2 pathway activation by iAs has been reported in various cell types, however, the experimental data in vivo are very limited and not fully elucidated in humans. The present investigation aimed to explore the hepatic and nephric NRF2 pathway upregulation in acute arsenic-exposed mice in vivo. Our results showed 10 mg/kg NaAsO₂ elevated the NRF2 protein and increased the transcription of Nrf2 mRNA, as well as up-regulated NRF2 downstream targets HO-1, GST and GCLC time- and dose-dependently both in the liver and kidney. Acute NaAsO₂ exposure also resulted in obvious imbalance of oxidative redox status represented by the increase of GSH and MDA, and the decrease of T-AOC. The present investigation reveals that hepatic and nephric NRF2 pathway expression is an early antioxidant defensive response upon iAs exposure. A better knowledge about the NRF2 pathway involvment in the cellular response against arsenic could help improve the strategies for reducing the cellular toxicity related to this metalloid.

A randomized clinical trial of the effects of ultra-low-dose naloxone infusion on postoperative opioid requirements and recovery

BACKGROUND

Tolerance to remifentanil during sevoflurane anesthesia may increase postoperative analgesic requirements. Low-dose naloxone not only has been shown to block the development of acute opioid tolerance but also to ameliorate undesired opioid-induced side effects. We hypothesized that naloxone prevents the acute opioid tolerance produced by a large dose of remifentanil, and reduces the incidence of opioid-induced side effects.

METHODS

Seventy-two patients undergoing open colorectal surgery were randomly assigned to receive intraoperative remifentanil (1) small dose at 0.1 μg/kg/min; (2) large dose at 0.30 μg/kg/min; or (3) large dose at 0.30 μg/kg/min combined with low-dose naloxone at 0.25 μg/kg/h just after the induction. Cumulative morphine consumption, postoperative pain scores, incidence of opioid-related side effects, time to recovery of bowel function, and length of hospital stay were recorded.

RESULTS

Cumulative morphine consumption at 24 h after surgery was higher in the large-dose remifentanil group (28 ± 12 mg) compared with the small-dose remifentanil group (17 ± 12 mg), and large-dose remifentanil-naloxone group (18 ± 9 mg), (P < 0.001). The median time to return of bowel function was shorter in the large-dose remifentanil-naloxone group than the other two groups (P < 0.05). The median length of hospital stay was lower in the large-dose remifentanil-naloxone group (8 [interquartile range: 8-12] days) compared with the small-dose remifentanil group (12 [interquartile range: 9-15] days) and large-dose remifentanil group (12 [interquartile range: 10-13] days), (P < 0.001).

CONCLUSION

Naloxone infusion prevented the acute opioid tolerance, provided a quicker recovery of bowel function, and reduced the length of hospital stay after open colorectal surgery.

Wall Mechanical Properties and Hemodynamics of Unruptured Intracranial Aneurysms

BACKGROUND AND PURPOSE

Aneurysm progression and rupture is thought to be governed by progressive degradation and weakening of the wall in response to abnormal hemodynamics. Our goal was to investigate the relationship between the intra-aneurysmal hemodynamic conditions and wall mechanical properties in human aneurysms.

MATERIALS AND METHODS

A total of 8 unruptured aneurysms were analyzed. Computational fluid dynamics models were constructed from preoperative 3D rotational angiography images. The aneurysms were clipped, and the domes were resected and mechanically tested to failure with a uniaxial testing system under multiphoton microscopy. Linear regression analysis was performed to explore possible correlations between hemodynamic quantities and the failure characteristics and stiffness of the wall.

RESULTS

The ultimate strain was correlated negatively to aneurysm inflow rate (P = .021), mean velocity (P = .025), and mean wall shear stress (P = .039). It was also correlated negatively to inflow concentration, oscillatory shear index, and measures of the complexity and instability of the flow; however, these trends did not reach statistical significance. The wall stiffness at high strains was correlated positively to inflow rate (P = .014), mean velocity (P = .008), inflow concentration (P = .04), flow instability (P = .006), flow complexity (P = .019), wall shear stress (P = .002), and oscillatory shear index (P = .004).

CONCLUSIONS

In a study of 8 unruptured intracranial aneurysms, ultimate strain was correlated negatively with aneurysm inflow rate, mean velocity, and mean wall shear stress. Wall stiffness was correlated positively with aneurysm inflow rate, mean velocity, wall shear stress, flow complexity and stability, and oscillatory shear index. These trends and the impact of hemodynamics on wall structure and mechanical properties should be investigated further in larger studies.