Experimental study on inhibition of rat ventricular Ik1 by RNA interference targeting the KCNJ2 gene

The dominant-negative inhibition of KCNJ2-encoded inward rectifier potassium channels (Kir2) is currently considered the best approach to biological pacemakers. We hypothesized that inhibition of the inward rectifier potassium current (IK1) in ventricular myocytes by RNA interference (RNAi) would convert ventricular myocytes into pacemaker cells. Five pieces of short hairpin RNA (shRNA) were designed to target the KCNJ2 gene and then plasmids incorporating shRNA and green fluorescent protein (GFP) as a marker were constructed for transfection into rat ventricular myocytes. The levels of KCNJ2 mRNA were analyzed with real-time quantitative RT-PCR to screen for pieces of shRNA that were effective at inhibiting the expression of the KCNJ2 gene. The activity of potassium ionic channels was then studied in the transfected ventricular myocytes. In the recombinant plasmids, LYS2 transfection significantly inhibited the mRNA of the KCNJ2 gene in comparison to other groups (p < 0.05), and the beating frequency of ventricular myocytes increased after LYS2 transfection. The open probability of IK1 potassium ion channels of cardiac myocytes transfected with the LYS2 plasmid was significantly downregulated (p < 0.05) and the IK1 of ventricular myocytes was also significantly suppressed compared to the negative group (p < 0.05). Our study demonstrated that IK1 was clearly inhibited after the inhibition of KCNJ2 gene expression by RNAi, and this may represent a new approach to the study of biological pacemakers.

The role of carbon dioxide insufflation in colonoscopy: a systematic review and meta-analysis

BACKGROUND AND STUDY AIMS

Insufflation of the intestinal tract, usually with room air, is necessary to improve visualization during colonoscopy. However, most patients complain of bowel distension and abdominal pain afterwards. Recently, carbon dioxide (CO2) rather than air insufflation has been used. We aimed to evaluate the efficiency, safety, and comfort of colonoscopy CO2 insufflation, with systematic review and meta-analysis of published randomized controlled trials (RCTs).

METHODS

Databases including PubMed, EMBASE, the Cochrane Library, the Science Citation Index, and important meeting abstracts were searched and evaluated by two reviewers independently.

RESULTS

Nine RCT studies involving 1577 patients were analyzed. There was significant heterogeneity for some major results; we analyzed these using a random-effects model. Meta-analysis showed fewer patients with abdominal pain in the CO2 group during the procedure (relative risk [RR] 0.77, 95% confidence intervals [CI] 0.62-0.96), and post procedure at 1 hour (0.26, 0.16-0.43), 6 hours (0.36, 0.20-0.64), and 24 hours (0.53, 0.31-0.91). The number needed to treat (NNT) during the procedure was 7; post procedure, the NNT at 1 hour was 2, at 6 hours it was 3, and at 24 hours it was 12. Compared with air, CO2 insufflation was associated with less passage of flatus post procedurally, at 1 hour (RR 0.09, 95%CI 0.03-0.24) and 6 hours (0.30, 0.14-0.62). There were no significant differences between the two groups regarding safety, gas volume, and cecal intubation rate.

CONCLUSIONS

Insufflation with CO2 in colonoscopy could decrease abdominal discomfort during and following the procedure, without any additional adverse reactions, warranting routine clinical use.

Detection of Breast Lesions using an Automated Breast Volume Scanner System

OBJECTIVE: This study investigated the clinical utility of an automated breast volume scanner (ABVS) system for the detection of breast lesions. METHODS: The breasts of 81 patients referred for ultrasonographic examination were scanned using the ABVS system and handheld ultrasonography independently by two experienced examiners. The ABVS was used to perform scans of the breast in three directions (anteroposterior, lateral and medial), with the addition of further inferior and superior scans if necessary. The scanning data were then stored and automatically reconstructed. For hand-held ultrasonography the whole breast was scanned radially from the outside to the centre of the nipple. RESULTS: The numbers of lesions reported by the two examiners were 89 and 99, respectively, using the ABVS (not statistically significant), compared with 60 and 85, respectively, using handheld ultrasonography (statistically significant). CONCLUSIONS: The ABVS system is an operator-independent method for automated breast scanning. It detected more breast lesions and provided additional information for the diagnosis of intraductal and malignant lesions compared with hand-held ultrasonography.

Identification of a novel HLA-B*40 allele, B*40:162, in a Chinese individual

The allele was identified in a Chinese individual by sequence-based typing. HLA-B*40:162 differs from B*40: 06:01 by a single nucleotide at position 272 C→T in exon 2.

Clinical efficacy of chemotherapy combined with verapamil in metastatic colorectal patients

In order to determine the clinical efficacy and adverse reactions of chemotherapy and verapamil infusion through a target artery to treat colorectal cancer patients with metastasis after failure with previous conventional treatments. Patients with metastatic colon cancer (n = 36) received an infusion of verapamil, interleukin-2, oxaliplatin (or hydroxy camptothecin or irinotecan hydrochloride), fluorouracil and calcium folinate through target artery using the Seldinger puncture technique. From the second day of infusion, the patients were treated with fluorouracil and calcium folinate via systematic intravenous injection for 2-3 days. Efficacy was evaluated after at least two treatment courses. The objective response including complete or partial response was 58.3% in the 36 patients; clinical benefit rate, evaluated by Karnofsky Performance Status score was 91.7%; by weight was 83.3%; by the amount of painkiller consumed was 80.6%. No patient experienced side effects associated with heart function. Post-treatment, the P-R period, Q-T period, QRS, and heart rate were not significantly different than before treatment. Liver function was significantly improved. Side effects of chemotherapy were minor in comparison to those observed with intravenous chemotherapy. Infusion of verapamil and chemotherapy directly into pelvic tumor tissue can increase treatment efficacy and has been shown to be a relatively safe technique.

Inhibition of IκB Kinase β attenuates hypoxia-induced inflammatory mediators in rat renal tubular cells

OBJECTIVE

Inflammation is now believed to play a major role in the pathophysiology of ischemic acute kidney injury (AKI), which is thought to be directly regulated by nuclear factor-κB (NF-κB). Our previous study indicated that ischemic preconditioning (IPC) alleviated renal ischemic-reperfusion injury due to inhibition of IκB kinase β (IKK β) activity. Using small interfering RNA (siRNA) to silence the expression of IKKβ, which consists of the IKK complex residing at a key convergence site that leads to NF-κB activation in multiple signaling pathways, we protected organs from ischemic AKI. Herein, we have report a siRNA-based treatment to prevent ischemic AKI.

METHODS

Ischemic AKI was induced by a hypoxia-mimicking agent cobalt chloride (CoCl(2)). The therapeutic effects of IKKβ-specific siRNA were evaluated on the expression of interleukin (IL)-18, neutrophil gelatinase-associated lipocalin (NGAL), and cell apoptosis.

RESULTS

Compared with CoCl(2)-induced NRK52E cells, pretransfected IKKβ-specific siRNA reduced the expression of IL-18 and NGAL to 62.5% and 50.4% in messenger RNA (mRNA) and to 57.2% and 62.7% in protein levels, respectively. The necrosis index in the IKKβ-specific siRNA transfected group was decreased compared with a nonspecific siRNA transfected group.

CONCLUSIONS

These data revealed that hypoxia-induced inflammatory responses were IKKβ/NF-κB-dependent. Knockdown of IKKβ by siRNA suppressed the transcription IKKβ/NF-κB-mediated inflammatory mediators in tumor necrosis factor-α or CoCl(2)-treated tubular epithelial cells, and decreased CoCl(2)-induced cell death, which may be a useful, preventive and therapeutic strategy for ischemic AKI.

Renal haemodynamics in patients with liver cirrhosis assessed by colour ultrasonography

Colour Doppler flow imaging was used in this prospective, cross-sectional study to analyse renal haemodynamics in 50 cirrhotic patients and 15 healthy controls. Mean renal arterial resistive index (RI) was higher in cirrhotic patients than in healthy controls. Mean RI was also higher in cirrhotic patients with non-refractory ascites than in those without ascites, suggesting that the degree of renal vasoconstriction varies with the severity of ascites. A gradient of RI values across the main renal artery, interlobar artery and interlobular renal artery was retained in cirrhotic patients even in the decompensatory stage with non-refractory ascites but was not present in the decompensatory stage with refractory ascites. The disappearance of this gradient may be an important prognostic factor in the development of hepatorenal syndrome (HRS). An inverse correlation between creatinine clearance and interlobular arterial RI was shown for all cirrhotic patients suggesting that even patients with refractory ascites are in a prophase of HRS.

Relationship between Cytochrome P450 2C19*2 Polymorphism and Stent Thrombosis following Percutaneous Coronary Intervention in Chinese Patients Receiving Clopidogrel

This study investigated the relationship between the cytochrome P450 2C19 (CYP2C19) *2 polymorphism (681A) and definite stent thrombosis (ST) in patients undergoing percutaneous coronary intervention (PCI) and receiving clopidogrel (75 mg/day, orally). The CYP2C19*2 polymorphism status of 1738 Chinese patients with coronary artery disease was examined. The primary endpoint was the occurrence of definite ST during the 180-day follow-up period. The presence of at least one CYP2C19*2 allele was significantly associated with increased ST risk (19 CYP2C19*2/*2 or *1/*2 patients [2.4%] versus seven homozygous wild-type CYP2C19*1/*1 patients [0.75%]). The risk of definite ST was highest in patients with the CYP2C19*2/*2 genotype. The CYP2C19*2 genotype is associated with an increased risk of definite ST following coronary stent placement among Chinese patients with coronary artery disease receiving clopidogrel.

Predictive Value of Penile Dynamic Colour Duplex Doppler Ultrasound Parameters in Patients with Post-Traumatic Urethral Stricture

This study evaluated dynamic colour duplex Doppler ultrasound (D-CDDU) for the assessment of erectile function in patients with post-traumatic urethral stricture. In total, 44 patients with urethral stricture secondary to trauma were recruited between January 2009 and June 2010. Peak systolic velocity of the cavernosal artery was measured before and after intracavernosal injection (ICI) of 20 mg papaverine and 1 mg phentolamine. Cavernosal artery end-diastolic velocity and resistance index (RI) were evaluated after ICI. Patients with RI ≥ 0.8 had significantly shorter strictures than those with RI < 0.8 after ICI only in cases of posterior urethral stricture. Patients with RI ≥ 0.8 were significantly younger than those with RI < 0.8. Urethral stricture length was negatively correlated with RI ( r = −0.375). Cavernosal artery RI after ICI is a reliable predictor of erectile function in patients with urethral stricture, especially posterior stricture. The patient's age should be considered when using this parameter.

Structure, morphology and magnetic properties of Mg((x))Zn((1 - x))Fe2O4 ferrites prepared by polyol and aqueous co-precipitation methods: a low-toxicity alternative to Ni((x))Zn((1 - x))Fe2O4 ferrites

The synthesis and properties of Mg((x))Zn((1 - x))Fe(2)O(4) spinel ferrites as a low-toxicity alternative to the technologically significant Ni((x))Zn((1 - x))Fe(2)O(4) ferrites are reported. Ferrite nanoparticles have been formed through both the polyol and aqueous co-precipitation methods that can be readily adapted to industrial scale synthesis to satisfy the demand of a variety of commercial applications. The structure, morphology and magnetic properties of Mg((x))Zn((1 - x))Fe(2)O(4) were studied as a function of composition and particle size. Scanning electron microscopy images show particles synthesised by the aqueous co-precipitation method possess a broad size distribution (i.e. ∼ 80-120 nm) with an average diameter of the order of 100 nm ± 20 nm and could be produced in high process yields of up to 25 g l(-1). In contrast, particles synthesised by the polyol-based co-precipitation method possess a narrower size distribution with an average diameter in the 30 nm ± 5 nm range but are limited to smaller yields of ∼ 6 g l(-1). Furthermore, the polyol synthesis method was shown to control average particle size by varying the length of the glycol surfactant chain. Particles prepared by both methods are compared with respect to their phase purity, crystal structure, morphology, magnetic properties and microwave properties.

Effects of acoustic stimuli on neuronal activity in the auditory cortex of the rat

Spontaneous activity of cortical neurons exhibits alternative fluctuations of membrane potential consisting of phased depolarization called "up-state" and persistent hyperpolarization called "down-state" during slow wave sleep and anesthesia. Here, we examined the effects of sound stimuli (noise bursts) on neuronal activity by intracellular recording in vivo from the rat auditory cortex (AC). Noise bursts increased the average time in the up-state by 0.81+/-0.65 s (range, 0.27-1.74 s) related to a 10 s recording duration. The rise times of the spontaneous up-events averaged 69.41+/-18.04 ms (range, 40.10-119.21 ms), while those of the sound-evoked up-events were significantly shorter (p<0.001) averaging only 22.54+/-8.81 ms (range, 9.31-45.74 ms). Sound stimulation did not influence ongoing spontaneous up-events. Our data suggest that a sound stimulus does not interfere with ongoing spontaneous neuronal activity in auditory cortex but can evoke new depolarizations in addition to the spontaneous ones.

Search for effects beyond the born approximation in polarization transfer observables in e(over→)p elastic scattering

Intensive theoretical and experimental efforts over the past decade have aimed at explaining the discrepancy between data for the proton electric to magnetic form factor ratio, G(E)/G(M), obtained separately from cross section and polarization transfer measurements. One possible explanation for this difference is a two-photon-exchange contribution. In an effort to search for effects beyond the one-photon-exchange or Born approximation, we report measurements of polarization transfer observables in the elastic H(e[over →],e(')p[over →]) reaction for three different beam energies at a Q(2)=2.5  GeV(2), spanning a wide range of the kinematic parameter ε. The ratio R, which equals μ(p)G(E)/G(M) in the Born approximation, is found to be independent of ε at the 1.5% level. The ε dependence of the longitudinal polarization transfer component P(ℓ) shows an enhancement of (2.3±0.6)% relative to the Born approximation at large ε.

A soluble thymic stromal lymphopoietin (TSLP) antagonist, TSLPR-immunoglobulin, reduces the severity of allergic disease by regulating pulmonary dendritic cells

Recent studies show that thymic stromal lymphopoietin (TSLP) plays a critical role in the upstream phase of the allergic cascade to induce T helper type 2 cell (Th2)-dominant allergic diseases. However, the effect of blocking TSLP signalling with the soluble TSLP receptor (TSLPR), TSLPR-immunoglobulin (Ig), on asthma development needs further investigation. Here, we examined the effects of TSLPR-Ig on asthmatic airway inflammation and dendritic cell (DC) function. TSLPR-Ig (comprising the extracellular domain of murine TSLPR and an IgG2a Fc tail) purified from transfected COS-7 cells reduced the expression of CD40, CD80 and CD86 on TSLP-activated DCs in vitro. We also investigated the mechanisms underlying TSLPR-Ig-mediated amelioration of allergic airway inflammation in a murine asthma model. When TSLP signalling was blocked by intratracheal administration of TSLPR-Ig prior to sensitization, allergen-specific serum IgE levels, airway tissue inflammation, inflammatory cell infiltration and Th2 cytokine levels in the bronchiolar lavage fluid (BALF) were reduced significantly. This was because of the TSLP-Ig-mediated down-regulation of co-stimulatory molecule expression on pulmonary DCs. We also transferred bone marrow-derived mature DCs (mDCs) into the airways of asthmatic mice. Intratracheal administration of TSLPR-Ig prior to the transfer of mDCs reduced eosinophilic airway inflammation and Th2 differentiation significantly. Collectively, these data suggest that local use of TSLPR-Ig prevents airway inflammation, at least in part, by regulating DC function, and that blocking TSLP signalling using TSLPR-Ig may be a novel strategy for the treatment of asthma bronchiale.

Helical tomotherapy for anal cancer: Initial clinical outcomes and organ motion

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Background: Helical tomotherapy (HT) delivers rotational IMRT with megavoltage CT (MVCT) guidance for patient positioning, offering improved dose conformality and accuracy. We report preliminary clinical outcomes using HT in patients with anal cancer with estimated organ motion and delivered doses.

Methods: From 9/2005-8/2009, 15 patients with anal cancer were treated with HT and concurrent chemotherapy (MMC 10 mg/m2 IV bolus d1 and 29; 5FU 1,000 mg/m2/day CI d1-4 and 29-32). Median doses for primary tumor, involved lymph nodes and uninvolved lymph nodes were 50.5, 50.4 and 45 Gy. Dose specifications and target definitions were per RTOG 0529 for the majority. Treatment plans, daily MVCT, and initial clinical outcomes and toxicity were retrospectively analyzed. Center-of-mass (COM) locations and volumes of the targets and OAR with daily shifts were analyzed on selected patients. Doses actually delivered daily were reconstructed.

Results: At median follow-up of 15 months, all patients were alive without any evidence of recurrence. There were 40% male, 27% HIV+, 13% T3/4, and 47% lymph node positive. Four patients required treatment break of ≤ 1 week. There were no non-hematologic grade 4/5 toxicities. Overall non-hematologic grade 3 toxicity was 33.3% (GI and skin). All other patients had ≤ grade 2 GI or skin toxicity that completely resolved with aggressive supportive care. There was 40% overall hematologic grade 4 toxicity. Overall hematologic grade 3 toxicity was 60%. Daily shifts were 0.6 ± 3.3, 0.4 ± 3.0, and 0.5 ± 2.2 (SD) mm in lateral, longitudinal and vertical directions. Average daily displacements of the COM from their locations on the planning CT were 9 ± 3, 7 ± 4, 9 ± 2, and 7 ± 2 (SD) mm, for anus, rectum, bladder and vulva. Interfractional organ motion and deformation resulted in variations in the dose delivered in each fraction.For example, daily dose covering 95% of PTV varied by 4%, and vulva volume covered by 50 Gy changed by 23% daily.

Conclusions: HT with concurrent chemotherapy is well-tolerated compared to historical reports. Interfractional organ motion is significant and can result in deviations in dose delivery to the target and OAR. Such deviations should be considered in analyzing dose response outcome.

No significant financial relationships to disclose.

Factors associated with occupational strain among Chinese teachers: a cross-sectional study

OBJECTIVES

With the reform of the education system in China, teachers are suffering from more occupational strain, which is believed to impair their working state indirectly and affect their health. This study assessed occupational strain and explored the related factors among Chinese teachers.

STUDY DESIGN

Cross-sectional with cluster sampling.

METHODS

The study population was composed of 3570 school teachers working in 64 primary and middle schools in Heping District in Shenyang, China. Data were collected using a self-administered questionnaire (the Chinese version of the Occupational Stress Inventory scale). Multivariate linear regression analyses were performed to study the factors related to occupational strain.

RESULTS

The average score on the Personal Strain Questionnaire (PSQ) for the whole study population was 106.5 (107.5 in men and 106.3 in women). Teachers with chronic disease, a greater number of days of sick leave, recent experience of a stressful life event and divorced/separated/widowed status tended to suffer greater strain than their peers. Regression analyses showed that the PSQ score was significantly associated with role overload, role boundary, responsibility and physical environment, and inversely associated with recreation and rational coping. The most crucial predictors of occupational strain were chronic disease, days of sick leave, recent experience of a stressful life event and marital status. Being a class teacher was the strongest indicator of interpersonal strain. Self-care was associated with vocational strain and psychological strain, and inversely associated with physical strain.

CONCLUSIONS

Most teachers in this study experienced a high degree of occupational strain. Chronic disease, days of sick leave, recent experience of a stressful life event and divorced/separated/widowed status played prominent roles in occupational strain. In addition, role overload, role boundary, responsibility and physical environment induce occupational strain, while recreation and rational coping have a positive effect on occupational strain. Interventions such as proper management of chronic diseases and establishment of a balanced work-family life are crucial to reduce occupational strain. Recreation and training in coping abilities are needed to enhance positive working environments and attenuate the occupational strain imposed on teachers.

A phase II, open-label, multicenter, prospective study of paclitaxel plus capecitabine with subsequent capecitabine maintenance therapy as first-line treatment for metastatic or recurrent gastric cancer

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Background: Paclitaxel has been shown to be effective in AGC. We assess the efficacy and safety of PX-X therapy as first-line treatment for metastatic or recurrent GC in a phase II, multicenter, prospective study.

Methods: Patients with previously untreated gastric adenocarcinoma, signed informed consent, target lesion(s), KPS ≥ 70 and adequate organ functions are eligible. Paclitaxel was given as 80 mg/m2 by 3-hour infusion day 1,8, capecitabine 1,000 mg/m2, BID, D1-14, Q3W. Cycles were repeated until progression or maximum 6 or AEs. Then the patients without progression began the second stage treatment as X with same dose/schedule until progression or AEs. PFS, RR, DCR, OS and AEs are the end points evaluated in this study.

Results: From 12/2006 to 4/2010, 195 patients (ITT) were enrolled in 21 centers, 1 patient was withdraw due to allergy to paclitaxel, 194 cases were PP. After median follow up of 16.2 months, 16 cases lost. In ITT, 119 pts progressed, 104 pts died. Mean cycles the patients completed was 5. CR and PR were achieved in 1.0% (2 pts) and 32.3% (63 pts) of pts (RR 33.3%), 75 pts had SD (38.5%), 25 pts (12.8%) progressed. PFS of ITT is 208 d (95% CI: 169.1-246.8) and estimated OS is 456 d (95%CI: 286.9-624.2). 45 pts continued to X after PX with good tolerance, median cycles accepted was 4, and OS was longer than 590 d. 23 patients accepted surgery after chemotherapy; the survival data have not been reached. After disease progression, 61 cases accepted second-line treatment, including oxaplatin/irinotecan-based chemotherapy, target therapy, and local therapy. AEs were mild and the grade 3/4 toxicities were leucopenia (13.8%), alopecia(13.3%), neutropenia (8.2%), fatigue (6.7%), nausea/vomiting (5.1%), HFS (5.1%), diarrhea(3.6%), neurotoxicity (3.1%), hepatic dysfuction (2.6%), and anaphylactic shock (0.5%). No treatment- related deaths were recorded in all patients.

Conclusions: PX-X as first-line treatment was promising in advanced gastric cancer. Further evaluation of this combination therapy is being carried on phase III clinical trial of ML22697.

No significant financial relationships to disclose.