Rounded leaf end effect of multileaf collimator on penumbra width and radiation field offset: an analytical and numerical study

Background

Penumbra characteristics play a significant role in dose delivery accuracy for radiation therapy. For treatment planning, penumbra width and radiation field offset strongly influence target dose conformity and organ at risk sparing.

Methods

In this study, we present an analytical and numerical approach for evaluation of the rounded leaf end effect on penumbra characteristics. Based on the rule of half-value layer, algorithms for leaf position calculation and radiation field offset correction were developed, which were advantageous particularly in dealing with large radius leaf end. Computer simulation was performed based on the Monte Carlo codes of EGSnrc/BEAMnrc, with groups of leaf end radii and source sizes. Data processing technique of curve fitting was employed for deriving penumbra width and radiation field offset.

Results

Results showed that penumbra width increased with source size. Penumbra width curves for large radius leaf end were U-shaped. This observation was probably related to the fact that radiation beams penetrated through the proximal and distal leaf sides. In contrast, source size had negligible impact on radiation field offset. Radiation field offsets were found to be constant both for analytical method and numerical simulation. However, the overall resulting values of radiation field offset obtained by analytical method were slightly smaller compared with Monte Carlo simulation.

Conclusions

The method we proposed could provide insight into the investigation of rounded leaf end effects on penumbra characteristics. Penumbra width and radiation field offset calibration should be carefully performed to commission multileaf collimator for intensity modulated radiotherapy.     

Withdrawal of repeated morphine enhances histamine-induced scratching responses in mice

An itch is experientially well known that the scratching response of conditions such as atopic dermatitis is enhanced under psychological stress. Morphine is typical narcotic drug that induces a scratching response upon local application as an adverse drug reaction. Although long-term treatment with morphine will cause tolerance and dependence, morphine withdrawal can cause psychologically and physiologically stressful changes in humans. In this study, we evaluated the effects of morphine withdrawal on histamine-induced scratching behavior in mice. Administration of morphine with progressively increasing doses (10–50?mg/kg, i.p.) was performed for 5 consecutive days. At 3, 24, 48, and 72?hr after spontaneous withdrawal from the final morphine dose, histamine was intradermally injected into the rostral part of the back and then the number of bouts of scratching in 60?min was recorded and summed. We found that at 24?hr after morphine withdrawal there was a significant increase in histamine-induced scratching behavior. The spinal c-Fos positive cells were also significantly increased. The relative adrenal weight increased and the relative thymus weight decreased, both significantly. Moreover, the plasma corticosterone levels changed in parallel with the number of scratching bouts. These results suggest that morphine withdrawal induces a stressed state and enhances in histamine-induced scratching behavior. Increased reaction against histamine in the cervical vertebrae will participate in this stress-induced itch enhancement.     

Effect of oxymatrine on CaMKII expression in sciatic nerve ligation-induced neuropathic pain in mice北大核心CSCD

Aim To observe the analgesic effect of oxymatrine (OMT) and its mechanism. Methods A peripheral mononeuropathy was produced in adult mice by placing loosely constrictive ligatures around the common sciatic nerve. The antinociceptive effects of the OMT were assessed in mechanical allodynia and cold allodynia tests. The CAMKII inhibitor KN-93 and AIP were adopted to investigate the influence of OMT on the analgesic effect and analyze its analgesic mechanisms. Western blot was used to evaluate the expressions of tCaMKII and pCaMKII protein. Results The intraperitoneal administration of OMT (160, 80 mg · kg-1) increased the paw withdrawal threshold in the mechanical allodynia test (P < 0. 05), OMT (160, 80, 40 mg · kg-1 , ip) remarkably decreased the paw lifts in the cold allodynia test (P < 0. 05). Ith KN-93 (1. 25 (μg/site), AIP (0. 02 μg/site) significantly enhanced the analgesic effect of OMT (35 mg · kg-1) (P<0. 01). Protein expression of pCaMKII was decreased by OMT(160 mg · kg-1). Conclusion OMT has significant protective effects on chronic constriction injury(CCI) in mice, and the effective mechanism of OMT inhibits the expression of CaMKII receptor.     

Optimal adjuvant therapy for resected hepatocellular carcinoma: a systematic review with network meta-analysis

Objectives

Major adjuvant therapies (ATs) for resected hepatocellular carcinoma (HCC) include chemotherapy, internal radiation therapy (IRT), interferon therapy (IFNT) and immunotherapy but the optimum regimen remains inconclusive. We aim to compare these therapies in terms of patient survival and recurrence rates.

Methods

We searched PubMed, EMBASE and Cochrane library databases for randomized trials comparing the above four therapies until 31 March 2014. We estimated the HRs for survival and ORs for overall recurrence among different therapies. Toxic effects were also evaluated.

Results

Fourteen eligible articles were included. IFNT improved 5-year survival greatly (HR 1.81, 95% CI 1.01–3.81, P = 0.034), whereas chemotherapy (HR 0.33, 95% CI 0.03–2.02), IRT (HR 0.31, 95% CI 0.02–3.33) and immunotherapy (HR 0.73, 95% CI 0.05–9.12) all provided a poorer survival outcome after 1-year. Similarly, for 5-year survival rates, although differing, IRT did not provide a significant improvement in survival (HR 1.38, 95% CI 0.34–5.19) compared with IFNT. Chemotherapy (HR 0.49, 95% CI 0.18–1.14) and immunotherapy (HR 0.56, 95% CI 0.17–1.59) did not appear to provide benefit over IFNT. Chemotherapy was ranked the worst in overall recurrence (OR 0.99, 95% CI 0.18–5.38) and most likely to cause toxic effects.

Conclusions

IFNT was the most efficacious AT regimen both for short and long term survivals. Immunotherapy and IFNT were the most two effective in preventing overall relapse for resected HCC.     

MicroRNA-29B (mir-29b) regulates the Warburg effect in ovarian cancer by targeting AKT2 and AKT3

Epithelial ovarian cancer (EOC) is the most lethal and aggressive gynecological malignancy, and abnormal cellular metabolism significantly contributes to cancer onset and progression. Here, we report that miR-29b negatively regulates AKT2/AKT3 expression, causing HK2/PKM2 downregulation and leading to a decreased Warburg effect and slowed ovarian cancer progression. Compared to normal ovaries, ovaries with epithelial cancer exhibited lower miR-29b expression at both cellular/histological levels. Glucose consumption and lactate production experiments confirmed miR-29b''s regulation of EOC metabolism. A luciferase reporter assay confirmed the direct binding of miR-29b to AKT2/AKT3 3′ UTRs. miR-29b silencing correlated with increased expression of AKT2/3, pAKT2/3, HK2, and PKM2. Pyruvic acid and NAD+/NADH levels also changed when miR-29b expression was suppressed; this effect could be blocked by specific AKT inhibitors, suggesting the miR-29b-AKT axis regulates the Warburg effect in ovarian cancer. In xenograft mouse models, miR-29b inhibited tumor formation in vivo. In vivo imaging also demonstrated that miR-29b agomir inhibited the relative uptake of ¹⁸F-FDG in the xenograft tumors, suggesting that miR-29b over-expression could negatively modulate tumor glucose metabolism in vivo. Taken together, our study suggests that miR-29b regulates the Warburg effect in EOC via AKT2/AKT3 and may provide novel options for future treatments for EOC.     

家庭干预对农村慢性精神分裂症患者作用的随访研究

目的探讨家庭干预对农村慢性精神分裂症患者的康复作用和其经济效益。方法将 90例慢性精神分裂症患者随机分为干预组和对照组各 45例 ;对干预组定期进行以心理教育为主的家庭干预 1年。在入组时、入组第 6个月和第 12个月用SDSS、SAPS、SANS、MRSS对两组患者进行评估 ,且比较两组 1年的经济收入和支出情况。结果在家庭干预的第 6个月和 12个月时 ,干预组SDSS、SAPS、SANS、MRSS的均值 ,及间接医疗费用均低于对照组 ,复工收入高于对照组 (均为P <0 .0 0 1)。结论对农村慢性精神分裂症患者实施家庭干预治疗 ,既有利于控制其病情和提高其社会功能 ,又可减轻患者家庭的经济负担     

实验性短期电刺激引起的机体紊乱

SourcepapersdealingwiththeuseofLateralElectricSurfaceStimulation（LESS）totreatidiopathicscoliosis（IS）inchildrenandadolescentshavesofarpresentedcontroversialopinions犤５，６，８，１０，１２，１６，１７犦．Authorsrecommendingthistreatmentusuallyapplyitfor９hoursatnight．Theymention，however，thatthetherapywhichmaylastuntilthebonesarefullydeveloped，oftenresultsinskincomplications，e．g．burns，emotionalandpsychicaldiscomfortofpatientsduringnoc－turnalrest，aswellasstressorevendisturbances…     

Domain-general and domain-specific aspects of temporal discounting in children with ADHD and autism spectrum disorders (ASD): A proof of concept study

It has been shown that delayed consumable rewards are discounted to a higher degree than money, which has been referred to as the “domain effect”. Until now the effects of reward type on temporal discounting (TD) have mainly been studied in adults. Although there is evidence that children with attention-deficit/hyperactivity disorder (ADHD) tend to show steeper TD of money than typically developing peers or children with autism spectrum disorders (ASD), it remains untested whether the domain effect is also seen in children with ADHD and ASD. To explore this we compared TD of children (8–16 year) with ADHD, ASD and typically developing controls with five different reward types. Seventy-two participants with ADHD, 69 with ASD and 130 controls performed two hypothetical TD-tasks: a monetary TD-task and a TD-task with one of four alternative rewards (material rewards, rewarding activities, food, social rewards). TD was seen for all reward types, but the rate of discounting was steeper for food, praise and rewarding activities compared to money, and for food and praise compared to material rewards. For the ADHD and control groups, but not the ASD group, money and material rewards were equally highly discounted. High correlations between TD of money and of activities, food and material rewards were found. In conclusion, a domain effect was observed in typically developing children, as well as in children with ADHD or ASD, although the pattern was somewhat different for ASD children. Despite this domain effect, there is also evidence for a domain-general aspect in TD.     

Antibiotics for nasopharyngitis are associated with a lower risk of office-based physician visit for acute otitis media within 14 days for 3- to 6-year-old children

Objectives  This study was designed to analyse factors potentially influencing children's return visits to physicians for symptoms of acute otitis media (AOM) within 14 days after being diagnosed with nasopharyngitis (NP), and the impact of recent antibiotic use.
Design  A controlled population-based pharmaco-epidemiological trial in 3- to 6-year-old children conducted from January to May 2000.
Setting  Three different geographical regions in France.
Participants  Among 2507 eligible children, 2456 could be analysed and 505 children had 634 office-based physician visits (OBPV) for NP symptoms.
Interventions  The statistical associations between antibiotics prescribed for NP and an OBPV for AOM within 14 days in a population-based study were analysed along with risk factors of AOM.
Main outcomes measure  Clinical events and antibiotic use.
Results  During the 2 weeks following physician-diagnosed NP, antibiotic use, especially a beta-lactam, significantly decreased the risk of OBPV for AOM in children (odds ratio = 0.2; 95% confidence interval = 0.09–0.7; P  = 0.002).
Conclusion  Antibiotics prescribed to children for NP seem to protect during the following 2 weeks against the risk of OBPV for AOM. It remains to be determined whether a subgroup at high risk of developing AOM after a viral infection exists and what might be the best strategy to adopt for NP in a national programme of optimal antibiotic use.