Dosimetric assessment of tumor control probability in intensity and volumetric modulated radiotherapy plans

OBJECTIVE:

Radiobiological models have been used to calculate the outcomes of treatment plans based on dose-volume relationship. This study examines several radiobiological models for the calculation of tumor control probability (TCP) of intensity modulated radiotherapy plans for the treatment of lung, prostate, and head and neck (H&N) cancers.

METHODS:

Dose volume histogram (DVH) data from the intensity modulated radiotherapy plans of 36 lung, 26 prostate, and 87  H&N cases were evaluated. The Poisson, Niemierko, and Marsden models were used to calculate the TCP of each disease group treatment plan. The calculated results were analyzed for correlation and discrepancy among the three models, as well as different treatment sites under study.

RESULTS:

The median value of calculated TCP in lung plans was 61.9% (34.1-76.5%), 59.5% (33.5-73.9%) and 32.5% (0.0-93.9%) with the Poisson, Niemierko, and Marsden models, respectively. The median value of calculated TCP in prostate plans was 85.1% (56.4-90.9%), 81.2% (56.1-88.7%) and 62.5% (28.2-75.9%) with the Poisson, Niemierko, and Marsden models, respectively. The median value of calculated TCP in H&N plans was 94.0% (44.0-97.8%) and 94.3% (0.0-97.8%) with the Poisson and Niemierko models, respectively. There were significant differences between the calculated TCPs with the Marsden model in comparison with either the Poisson or Niemierko model (p < 0.001) for both lung and prostate plans. The TCPs calculated by the Poisson and Niemierko models were significantly correlated for all three tumor sites.

CONCLUSION:

There are variations with different radiobiological models. Understanding of the correlation and limitation of a TCP model with dosimetric parameters can help develop the meaningful objective functions for plan optimization, which would lead to the implementation of outcome-based planning. More clinical data are needed to refine and consolidate the model for accuracy and robustness.

ADVANCES IN KNOWLEDGE:

This study has tested three radiobiological models with varied disease sites. It is significant to compare different models with the same data set for better understanding of their clinical applicability.

Implementation of the isocenter-shift technique for smoothing MLC field edge on a 3D treatment planning system

Stepped leaf edges are the major limitation of conforming to the prescribed treatment contour defined by the conventional multileaf collimator (MLC), which produces a scalloped dose pattern. The commercial HD-270 MLC (HDI) technique provides a software solution of the conventional MLC to achieve smoothed edge and optimal penumbra of the MLC shaped field. We implemented the HDI functionality on a 3D treatment planning system and compared the dosimetric effects of the HDI delivery in simulation with those in experiment for a number of the MLC fields. The fields from the contour of varied shapes with different sizes of the leaf stepping were tested for the HDI delivery. There is a good agreement of the dose distribution between the calculation as implemented in the planning system and the measurement performed on the treatment machine. It has been shown that the HDI delivery significantly smooths the stepped field edge with the reduced isodose undulation and effective penumbra. A problem may be present when the HDI is applied for the treatment of the circular contour of smaller diameter, and the conformity of the MLC shaping may not be achievable satisfactorily with the existing system. The optimization of leaf configuration is suggested to improve the conformity of the HDI technique. The HDI planning then can be used to assist in the decision making of applying the HDI treatment delivery.

Two-stage operation to treat destructive midfoot tuberculosis: 14 cases experience

INTRODUCTION

Tuberculosis (TB) in midfoot is often secondary to tuberculosis elsewhere in the body. The experience and literatures to treat midfoot tuberculosis are rare. Up until now, no successful method is reported to treat midfoot tuberculosis.

HYPOTHESIS

Stage surgery is an effective method to treat midfoot bone TB.

MATERIAL AND METHODS

Between January 2008 to January 2011, 14 patients who were diagnosed midfoot tuberculosis and suffered stage operation were enrolled. All the patients had been diagnosed definitely relying on imaging examination and laboratory tests preoperatively. Two-stage operation was performed to all patients. At the first stage, TB tissue and infective tissue were completely removed and replaced by antibiotic bone cement. Normal foot length and arch would be restored and maintained by K-wires and external fixators. At the second stage, autologous iliac and allogeneic bone graft were used to replace bone cement and by fixed by locking plates. American Orthopaedic Foot and Ankle Society (AOFAS), SF-36 and visual analogue scale (VAS) pain score were recorded at the last follow-up.

RESULTS

The average bone union time was 3.8 (range 3-6) months. There is no case of local recurrence or skin sinus. Neither implant broken nor screw loosen was present in this study. The AOFAS score was increased from 51.7±6.8 (range 43-61) preoperatively to 82.9±3.9 (range 76-90) postoperatively (P<0.001). The SF-36 score increased from 46.1±6.1 preoperatively to 83.1±5.4 postoperatively (P<0.001). The VAS score decreased from 6.1±1.1 preoperatively to 1.4±0.9 points postoperatively (P<0.001).

DISCUSSION

Stage operation is an effective treatment to stage III, IV midfoot tuberculosis.

LEVELS OF EVIDENCE

Level IV, retrospective.

Functional inhibition of regulatory CD4+CD25+T cells in peripheral blood of patients with pemphigus vulgaris

BACKGROUND

Pemphigus vulgaris (PV) is a potentially life-threatening autoimmune bullous disease affecting the skin and mucous membranes. Its pathogenic mechanism is still not fully understood. Regulatory T cells (Tregs) have been reported to play a significant role in regulating immune homeostasis in autoimmune disorders, such as PV.

AIM

To investigate the potential role of Tregs in the immunopathogenesis of PV.

METHODS

We enrolled 15 patients with PV and 15 healthy controls (HCs). Peripheral blood samples were collected from all participants before treatment. This was followed by flow cytometric, real-time reverse transcription PCR, and in vitro inhibition-based functional assays to explore the immunopathogenesis of Tregs in PV.

RESULTS

Our results showed no statistically significant differences in total CD4+CD25+ cells and CD4+CD25^high cells. In addition, expression levels of FOXP3 mRNA and the corresponding FOXP3 protein remained unchanged in the patients with PV and the HCs. However, the in vitro suppressive activity of CD4+CD25+ T cells was impaired in patients with PV compared with HCs.

CONCLUSIONS

Our observations suggest that inhibition of suppressive activity of Treg cells may be involved in the pathogenesis of PV.

qBrain-2, a POU domain gene expressed in quail embryos

We isolated a quail class III POU domain gene, qBrain-2, which was cloned from a cDNA library of E5 embryos. Northern blot and in situ hybridization analyses showed that qBrain-2 was expressed in developing central nervous system and adult brain. Moreover, qBrain-2 transcripts showed a dynamic distribution in embryonic central nervous system. Its transcripts were dominantly detected in the ventricular zone of the developing brain and spinal cord, but rarely in the differentiated region of mantle zone as well as the non-neuronal roof plate and floor plate. This suggests that qBrain-2 is involved in proliferation and differentiation of the neuroepithelial cells of quail central nervous system.

Chemopreventive effect of galangin against benzo(a)pyrene-induced stomach tumorigenesis through modulating aryl hydrocarbon receptor in Swiss albino mice

The present study was aimed to evaluate the chemopreventive potential of galangin against benzo(a)pyrene (BaP)-induced stomach carcinogenesis in Swiss albino mice. Stomach cancer was induced in experimental mice using BaP oral administration. The mice were treated with galangin (10 mg/kg b.wt.) before and during BaP administration. Oral administration of galangin at a dose of 10 mg/kg b.wt. significantly (p < 0.05) prevented the tumor incidence, tumor volume in the experimental animals. Further, galangin pretreatment prevents BaP-induced lipid peroxidation and restores BaP-mediated loss of cellular antioxidants status. It has also been found that galangin prevents BaP-induced activation of phase I detoxification enzymes. Furthermore, galangin pretreatment prevented the BaP-induced overexpression of cytochrome P450s isoform genes (CYP1A1, CYP1B1), aryl hydrocarbon receptor system (AhR, ARNT), transcriptional activators (CBP/p300, NF-kB), tumor growth factors, proto-oncogenes, invasion markers (TGFB, SRC-1, MYC, iNOS, MMP2, MMP9) and Phase II metabolic isoenzyme genes (GST) in the stomach tissue homogenate when compared to the control groups. The western blot results confirm that galangin (10 mg/kg. b.wt.) treatment significantly prevented the BaP-mediated expression of ArR, ARNT, and CYP1A1 proteins in the mouse stomach tissue. Therefore, the present results confirm that galangin prevents BaP-induced stomach carcinogenesis probably through modulating ArR and ARNT expression in the experimental mice.

Relative abundance of placental pro-atrial natriuretic factor mRNA in normal pregnancy and pre-eclampsia

Atrial natriuretic factor (ANF), produced by cytotrophoblast cells of the human placenta, may be involved in the regulation of uteroplacental blood flow. Pre-eclampsia is associated with maternal hypertension and reduced uteroplacental perfusion. The relationship between pre-eclampsia and placental production of ANF is not known. This study measured pro-ANF mRNA levels by Northern blot analysis in placentae delivered by caesarean section at preterm and term gestations from women with normotensive and pre-eclamptic pregnancies and found no significant difference between pre-eclampsia and normal pregnancy at either gestation. This result suggests that placental production of ANF is not altered at the pretranslational level during pre-eclampsia.

Optimal selection for multiple quantitative trait loci and contributions of individuals using genetic algorithm

Two methods (Scheme A and Scheme B) were developed to optimize the relative weights on quantitative trait loci (QTL) and contributions of selected individuals simultaneously to maximize selection response while constraining the rate of inbreeding to the rate observed in gene assisted selection (GAS). In Scheme A, both the relative weights give to QTL and contributions of the selected individuals were optimized using a genetic algorithm. The possible solutions for relative weights of QTL and contributions of the selected individuals were encoded simultaneously. A physical selection population was used to evaluate the fitness of each encoded solution using stochastic simulation with 50 replicates. The fitness of each solution was the mean of all replicates for accumulative discounted sum of genetic means of all generations in physical selection population. In Scheme B, the optimization for relative weights on QTL was similar to Scheme A, and also was implemented based on a genetic algorithm. However, unlike Scheme A, an optimal contribution algorithm (OC) was used to optimize contributions of selection candidates. When compared with GAS, Schemes A and B resulted in up to 15.88 and 22.26% extra discounted sum of genetic value of all generations in a long planning horizon, respectively. Compared GAS+OC and Scheme B, most of the increase (about 78%) in genetic gain was produced by only optimizing contributions of selected individuals. The optimization for relative weight given to QTL just avoided the long-term loss (about 22%) observed in GAS scheme.

[Genotype and phenotype of children with KCNA2 gene related developmental and epileptic encephalopathy]

Objective: To investigate the genotype and phenotype of children with KCNA2 gene related developmental and epileptic encephalopathy (DEE). Methods: Clinical data including the manifestations and electroencephalogram of 8 children with KCNA2 variants treated in the Department of Pediatrics, Peking University First Hospital from March 2017 to June 2019 were collected and analyzed retrospectively. Results: Among the 8 epileptic patients with KCNA2 variants, 5 were males and 3 were females. The age of onset was from 1 day to 11 months. The age at last follow-up ranged from 4 months to 86 months. Two variants including c.1214C>T (loss-of-function) and c.1120A>G (gain-and loss-of-function) were identified. The variant of c.1214C>T was found in six patients (case 1-6). For these patients, the age of onset was from 5 to 11 months and they were characterized by multiple seizure types. All had focal seizures and had normal development before seizure onset with developmental regression after seizure onset. The first electroencephalogram showed epileptic discharges in Rolandic region in two, epileptic discharges in Rolandic region combined with generalized discharge in one, generalized discharge with posterior predominance in two (combined with or transferred to Rolandic region during the course) and epileptic discharges in posterior region combined with generalized discharge in one. And in 5 of them the Rolandic discharges developed into epileptic electrical status (ESES) during sleep. All the six patients were still treated with a combination of multiple antiepileptic drugs. Two of them had seizure controlled at 80 months and 68 months, respectively. The variant of c.1120A>G were identified in two of eight patients (case 7 and 8) and they had seizure onset on the 1st day after birth. Their epileptic seizures were frequent and difficult to control. They had remarkably developmental delay and microcephaly since birth. One case (case 8) had a wide forehead. They had frequent seizures up to the last follow-up. In case 7, the early electroencephalogram showed epileptic discharges in temporal region, and interictal electroencephalogram at 3 months of age showed multifocal discharge with posterior and temporal region predominance. In case 8, the early electroencephalogram was normal and electroencephalogram showed burst suppression at 2 months of age, and it developed epileptiform discharge in posterior region at 1 year of age. Conclusions: KCNA2 gene variants can lead to DEE with multiple seizures types. Among them, loss-of-function c.1214C>T is the most common, and these patients have seizure onset at infancy with Rolandic discharges tended to develop into to ESES pattern. The variant of c.1120A>G is a gain-of- and loss-of-function variant, patients with c.1120A>G have seizure onset in neonatal period, the phenotype overlaps with the former but is more severe.

Low-Pass Filtering Empirical Wavelet Transform Machine Learning Based Fault Diagnosis for Combined Fault of Wind Turbines

Fault diagnosis of wind turbines is of great importance to reduce operating and maintenance costs of wind farms. At present, most wind turbine fault diagnosis methods are focused on single faults, and the methods for combined faults usually depend on inefficient manual analysis. Filling the gap, this paper proposes a low-pass filtering empirical wavelet transform (LPFEWT) machine learning based fault diagnosis method for combined fault of wind turbines, which can identify the fault type of wind turbines simply and efficiently without human experience and with low computation costs. In this method, low-pass filtering empirical wavelet transform is proposed to extract fault features from vibration signals, LPFEWT energies are selected to be the inputs of the fault diagnosis model, a grey wolf optimizer hyperparameter tuned support vector machine (SVM) is employed for fault diagnosis. The method is verified on a wind turbine test rig that can simulate shaft misalignment and broken gear tooth faulty conditions. Compared with other models, the proposed model has superiority for this classification problem.

Potential low toxic alternative for Na-Cl cotransporter inhibition: A diuretic effect and mechanism study of Pyrrosia petiolosa

BACKGROUND

Hydrochlorothiazide, a diuretic commonly used for the treatment of hypertension, is often associated with serious metabolic side effects. Pyrrosia petiolosa (Christ) Ching is a traditional Chinese medicine that possesses diuretic properties, without any obvious side effects.

AIM

To evaluate the diuretic effect of P. petiolosa (Christ) Ching and to elucidate its underlying mechanism of action.

METHODS

Extracts obtained from different polar components of P. petiolosa (Christ) Ching were analyzed for toxicity in a Kunming mouse model. The diuretic effects of the extracts were compared to that of hydrochlorothiazide in rats. In addition, compound isolation procedures, cell assays of Na-Cl cotransporter inhibition and rat diuretic test of monomeric compounds were conducted to identify the active ingredients in the extract. Subsequently, homology modeling and molecular docking were performed to explain the reason behind the diuretic activity observed. Finally, LC-MS analysis was used to elucidate the underlying mechanism of action of P. petiolosa (Christ) Ching.

RESULTS

No toxicity was observed in mice administered P. petiolosa (Christ) Ching extracts. The ethyl acetate fraction showed the most significant diuretic effect. Similar results were obtained during the analysis for Na+ content in rat urine. Further separation of P. petiolosa (Christ) Ching components led to the isolation of methyl chlorogenate, 2',3'-dihydroxy propyl pentadecanoate, and β-carotene. Results from cell assays showed that the Na-Cl cotransporter inhibitory activity of methyl chlorogenate was greater than that of hydrochlorothiazide. This result was again confirmed by the diuresis tests of monomeric compounds in rats. The molecular simulations explain the stronger interactions between the methyl chlorogenate and Na-Cl cotransporter. Of the compounds determined using LC-MS analysis, 185 were identified to be mostly organic acids.

CONCLUSIONS

P. petiolosa possesses significant diuretic activities without any obvious toxicity, with least two possible mechanisms of action. Further study on this herb is warranted.

Improved Dose Conformity for Adjacent Targets: A Novel Planning Technique for Gamma Knife Stereotactic Radiosurgery

Purpose

In the current Gamma Knife (GK) planning system (GammaPlan, version 10.2, Elekta AB, Stockholm, Sweden), multiple adjacent brain metastasis (BMs) had to be planned sequentially if BMs were drawn separately, leading to less conformal target dose in the composite plan due to inter-target dose contribution and fine-tuning of the shots being quite tedious. We proposed a method to improve target dose conformality and planning efficiency for such cases.

Methods and Materials

Fifteen patients with multiple BMs treated on the Leksell GK Perfexion system were retrospectively replanned in the Institutional Review Board (IRB) approved study. The recruitment criterion was all the BMs should be entirely encompassed within the maximum dose grid allowed in the GammaPlan. The BMs were first planned sequentially as routine clinic cases. The contours of the BMs were then exported to the VelocityAI (Varian, CA, USA) to generate a composite contour after a union operation, and all the BMs were planned again simultaneously using this composite contour in the GammaPlan. The inverse planning (IP) was employed in both methods with the same treatment time allowed for a fair plan comparison. Dose evaluation was performed in the VelocityAI with all planning magnetic resonance (MR) images, structure set and dose were exported to the VelocityAI. The dosimetery parameters, including conformality index (CI), V20Gy, V16Gy, V12Gy, and V5Gy, were compared between the two methods.

Results

The planning results from both methods were reviewed qualitatively and quantitatively. The proposed method exhibited superior CI, except for an outlier case with very tiny BMs. The mean and standard deviation (std.) of the Paddick CI for all patients were 0.76±0.11 for the proposed method, comparing to 0.69±0.13 for the sequential method. The V20Gy, V16Gy, V12Gy, and V5Gy for the proposed method were 10.9±0.9%, 9.5±10.2%, 6.2±16.4% and 3.3±21.8%, all lower than those from the sequential method.

Conclusions

The proposed method showed improved target dose conformality for all cases except for very tiny BMs. Planning efficiency is considerably better with the combined target technique. The improved dose conformality will be beneficial to patients in long term with lowered risk of radiation necrosis after GK stereotactic radiosurgery (SRS).

Effect of beam profile measurement on arc therapy plan quality assurance: a case study

We present an example when profile measurement and modeling of an Elekta Agility multileaf collimator (MLC) had a large effect specifically on arc therapy plan quality assurance (QA) results using ArcCheck. ArcCheck absolute dose measurements of these plans were systematically lower than planned by 3–10%. Failing QA results were seen even with unmodulated static and conformal arcs. Furthermore, the effect was found to be dependent on collimator angle, with worse results associated with near‐zero collimator angles. In contrast, step‐and‐shoot QA results were not affected. Changing the beam model to match steeper profile measurements obtained using a different measurement device resolved the problem. This case study demonstrates that conventional gamma index analysis can be sensitive to small profile modeling changes.

A new method to incorporate age and gender into the criteria for the detection of acute inferior myocardial infarction

Recent studies have shown that younger women are more likely to die during and after hospitalization for acute myocardial infarction (MI) than older women and men of all ages. This may be partly due to incorrect diagnosis or late detection of acute MI in younger women. At high specificity levels (>98%), the sensitivity of the initial ECG to detect acute MI may be as low as 30% when using traditional criteria by both physicians and computerized interpretation programs. This study examines if women of different age groups have a similar ECG presentation to men during acute inferior MI and if the diagnostic accuracies of the initial ECG are comparable. We analyzed chest pain ECGs from Mayo Clinic and Medical College of Wisconsin, which included 1,339 patients with acute inferior MI and 1,169 age-matched controls with noncardiac chest pain. We subdivided all groups by age (below and above 60 years) and compared ECG parameters (ST elevation, ST depression, QRS duration, R-wave amplitude, Q-wave duration and amplitude, QT interval) between genders. For inferior MI patients under age 60, women had lower ST elevations at the J point in lead II than men (57 +/- 91 microV vs. 86 +/- 117 microV, P < .02). This trend was reversed for patients over age 60 (lead a VF: 102 +/- 126 microV vs. 84+/-117 microV, P < .04; Lead III: 130+/-146 microV vs. 103+/-131 microV, P < .007). A neural network method was used to identify the most significant group of ECG parameters for detecting acute MI. An adaptive fuzzy logic method was developed for adapting to the threshold differences among the different gender and age groups. The new algorithm improved the sensitivity of acute inferior MI detection by more than 25% relative to old algorithm, while maintaining the high specificity around 98% for noncardiac chest pain patients.

Epileptic negative myoclonus restricted to lower limbs in benign childhood focal epilepsy with vertex spikes

BACKGROUND AND PURPOSE

The aim was to determine the electroclinical findings in benign childhood focal epilepsy with vertex spikes (BEVS) with epileptic negative myoclonus (ENM) restricted to the lower limbs.

METHODS

The electroencephalogram database of Peking University First Hospital and medical records of patients with BEVS and ENM restricted to the lower limbs were reviewed.

RESULTS

Twenty-seven patients with BEVS had ENM restricted to the lower limbs. Twelve started as ENM restricted to the lower limbs. The age at seizure onset ranged from 1.5 to 4.8 years. During the course, half of the 12 patients developed focal sensorimotor seizures and then were diagnosed as benign childhood epilepsy with centrotemporal spikes (BECTS), with BEVS (four cases) and without BEVS (two cases). Five of them had electrical status epilepticus during sleep (ESES) and met the diagnostic criteria of atypical benign partial epilepsy (ABPE). Fifteen of the 27 patients had ENM restricted to the lower limbs during the course. The age at seizure onset ranged from 1.3 to 9.8 years. All had ESES and were diagnosed as ABPE, 11 as ABPE with BEVS and four as ABPE evolving into BEVS.

CONCLUSIONS

Benign childhood focal epilepsy with vertex spikes (BEVS) might represent a specific epileptic syndrome of the continuum of benign childhood focal epilepsy. ENM restricted to the lower limbs was a special phenomenon in BEVS. BEVS could overlap with BECTS or evolve into BECTS and further into ABPE and vice versa. Ignorance of vertex spikes with associated ENM restricted to the lower limbs might lead to a misunderstanding of BEVS, a specific type of benign childhood focal epilepsy.

Integrated Four Comparative-Omics Reveals the Mechanism of the Terpenoid Biosynthesis in Two Different Overwintering Cryptomeria fortunei Phenotypes

Chinese cedar (Cryptomeria fortunei) is a tree species with important ornamental, medicinal, and economic value. Terpenoids extracted from the essential oil of C. fortunei needles have been considered valuable ingredients in the pharmaceutical and cosmetic industries. However, the possible gene regulation mechanisms that limit terpenoid biosynthesis in this genus are poorly understood. Here, we adopted integrated metabolome analysis, transcriptome, small-RNA (sRNA), and degradome sequencing to analyze the differences in terpenoid regulatory mechanisms in two different overwintering C. fortunei phenotypes (wild-type and an evergreen mutant). A total of 1447/6219 differentially synthesized metabolites (DSMs)/unigenes (DEGs) were detected through metabolome/transcriptome analyses, and these DSMs/DEGs were significantly enriched in flavonoid and diterpenoid biosynthesis pathways. In C. fortunei needles, 587 microRNAs (miRNAs), including 67 differentially expressed miRNAs (DERs), were detected. Among them, 8346 targets of 571 miRNAs were predicted using degradome data, and a 72-miRNA-target regulatory network involved in the metabolism of terpenoids and polyketides was constructed. Forty-one targets were further confirmed to be involved in terpenoid backbone and diterpenoid biosynthesis, and target analyses revealed that two miRNAs (i.e., aly-miR168a-5p and aof-miR396a) may be related to the different phenotypes and to differential regulation of diterpenoid biosynthesis. Overall, these results reveal that C. fortunei plants with the evergreen mutation maintain high terpenoid levels in winter through miRNA-target regulation, which provides a valuable resource for essential oil-related bioengineering research.

The effect of astragapolysaccharide on the lymphocyte proliferation and airway inflammation in sensitized mice

In order to investigate the regulating role of Astragapolysaccharide (APS) in the mice model of asthmatic airway inflammation, the airway eosinophil number, spleen T lymphocyte proliferation, level of IL-2 production and their relationships were studied in sensitized mice and sensitized mice treated with different concentrations of APS. The results showed that the number of eosinophils as well as lymphocytes in the airway of the sensitized animals were significantly increased, and a marked positive correlation between the inflammation cells and spleen T lymphocyte proliferation was found. Moreover, there was a positive correlation between inflammation cells and the level of IL-2 production. The APS of given dosage could significantly reduce the number of eosinophils in the airway of the sensitized animals. At the same time the level of IL-2 secreted by spleen T lymphocytes stimulated with ConA was also significantly decreased and there was a marked positive correlation between them. Our results suggested that APS of given dosage could prevent antigen-induced the number of eosinophils infiltrating into the airway of sensitized mice and inhibit the proliferation and activation of lymphocyte and IL-2 production. Through its immuno-regulating effect, APS can be helpful in the treatment of asthma.