A megavoltage scatter correction technique for cone-beam CT images acquired during VMAT delivery

Kilovoltage cone-beam CT (kV CBCT) can be acquired during the delivery of volumetric modulated arc therapy (VMAT), in order to obtain an image of the patient during treatment. However, the quality of such CBCTs is degraded by megavoltage (MV) scatter from the treatment beam onto the imaging panel. The objective of this paper is to introduce a novel MV scatter correction method for simultaneous CBCT during VMAT, and to investigate its effectiveness when compared to other techniques. The correction requires the acquisition of a separate set of images taken during VMAT delivery, while the kV beam is off. These images--which contain only the MV scatter contribution on the imaging panel--are then used to correct the corresponding kV/MV projections. To test this method, CBCTs were taken of an image quality phantom during VMAT delivery and measurements of contrast to noise ratio were made. Additionally, the correction was applied to the datasets of three VMAT prostate patients, who also received simultaneous CBCTs. The clinical image quality was assessed using a validated scoring system, comparing standard CBCTs to the uncorrected simultaneous CBCTs and a variety of correction methods. Results show that the correction is able to recover some of the low and high-contrast signal to noise ratio lost due to MV scatter. From the patient study, the corrected CBCT scored significantly higher than the uncorrected images in terms of the ability to identify the boundary between the prostate and surrounding soft tissue. In summary, a simple MV scatter correction method has been developed and, using both phantom and patient data, is shown to improve the image quality of simultaneous CBCTs taken during VMAT delivery.

Use of nanosilver in consumer products

Silver nanoparticles (AgNP; many other names such as nanosilver and colloidal silver) have already been used in everyday consumer products requiring broad spectrum antibiotic performance because of their enormous surface area and reactivity. Faunce and Watal [1] recently have critically analyzed the international regulatory issues for medical and domestic use in USA, EU, UK, and Australia. They found that in spite of the fact numerous studies have been made in the past decades, but many scientists are still uncertain of its safety. Very recently, Powers mentioned in her dissertation that her results showed positive that Ag+ and AgNP are developmental neurotoxicants in vitro and in vivo [2]. Therefore, there is a need to conduct a study to identify a global landscape of AgNPs and their products, and their manufacturers. A market- based intellectual property (IP) study has been conducted to examine the current global patent landscape of companies using AgNP in their consumer product development and production from 1980 to 2010. Detailed information in the compositions and formulations is extracted using a "two-stage" stage-gate process from the IP activity in the use of nanosilver. The first stage is in commercial products and the second stage is in consumer products. In the first stage for AgNP and AgNP-based commercial products, there were 7,422 patent families from January 1, 1980 to December 31, 2010. In the second stage for AgNP-based consumer products, 932 patent families from January 1, 1980 to December 31, 2010 were found. Korea, China and USA were found to be the major players in AgNP and AgNP-based commercial and consumer products. However, the recent patenting downturn was observed probably due to rising price in silver metal, regulatory uncertainty, public perception, and health safety & environmental (HS&E) issues.

Update of the HIPRO study: Late toxicity and outcome at seven years

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Background: Dose-escalated radiotherapy for localised prostate cancer improves disease control but at the expense of increased overall treatment time and late toxicity. Given the low alpha-beta ratio for prostate cancer, treatment with hypofractionation should be biologically advantageous. Intensity-modulated radiotherapy (IMRT) allows dose escalation with hypofractionation, while achieving acceptable levels of toxicity. We report our 7 year late toxicity data in patients treated with two such regimens within the Hypofractionated Dose Escalation utilising Intensity-modulated Radiotherapy in Carcinoma of the Prostate (HIPRO) study.

Methods: Sixty men, median age 75 years (50-87), with localised adenocarcinoma of prostate (T1-3NOMO) and either Gleason score ≥7 or PSA 20-50ng/L received 57Gy in 19 fractions (n=30) or 60Gy in 20 fractions (n=30) using 5-field inverse-planned IMRT. All patients received neoadjuvant hormone therapy, continuing for up to 6 months after treatment. Late toxicity was assessed at 7 years follow-up using RTOG criteria and LENT/SOMA questionnaire.

Results: Forty-four (73%) patients were alive at 7 years. Nine patients (21%) reported RTOG grade 1 bowel or bladder toxicity; there was no grade 2 toxicity or above and no difference between the fractionation schedules. LENT/SOMA questionnaires were returned by 31/44 patients. Mean and median scores were less than one for bowel and urinary symptoms. When compared with pre-treatment, the proportion of patients with significant (maximum LENT/SOMA ≥2) urinary symptoms remained similar (75% vs. 76%), problems with sexual function had decreased (84% vs. 98%) but bowel symptoms increased (62% vs. 25%). At 5 years, overall survival was 83% and 74% and cause-specific survival was 83% and 84% in the 57Gy and 60Gy groups respectively.

Conclusions: Dose-escalated hypofractionated IMRT for prostate cancer appears well tolerated with acceptable levels of late toxicity. Studies to assess long term disease control with these regimens are on-going.

No significant financial relationships to disclose.

Comparative analysis of abscisic acid-regulated transcriptomes in Arabidopsis

Transcription regulation by the phytohormone abscisic acid (ABA) plays a key role in responses to various stresses and has been extensively studied in Arabidopsis thaliana using different expression analysis techniques. Previous studies on comparative analysis of expression regulation by ABA and ABA-related stresses demonstrated marked differences in the targets of ABA. However, as few expression experiments were available during these studies, they encompass only a subset of ABA-regulated genes. The aim of the present work was to compare gene expression regulated by ABA administration in a wider range of expression experiments. Despite diversity in the actual set of genes regulated by ABA, all ABA-regulated transcriptomes shared some basic features, such as a common induced gene set, common functional targets and involvement of common regulatory mechanisms. Moreover, the cis-regulatory architecture of genes belonging to this set is expected to be of interest because of their sensitivity to ABA and apparent independence from other experimental variables. Comparative analysis of cis-regulatory element (CRE) enrichment also identified a novel CRE that is strongly associated with ABA signalling-mediated transcription repression.

Formulation and evaluation of omeprazole tablets for duodenal ulcer

Omeprazole pellets containing mucoadhesive tablets were developed by direct punch method. Three mucoadhesive polymers namely hydroxypropylemethylcellulose K4M, sodium carboxy methylcellulose, carbopol-934P and ethyl cellulose were used for preparation of tablets which intended for prolong action may be due to the attachment with intestinal mucosa for relief from active duodenal ulcer. Mucoadhesive tablets were coated with respective polymer and coated with Eudragit L100 to fabricate enteric coated tablets. The prepared tablets were evaluated for different physical parameters and dissolution study were performed in three dissolution mediums like 0.1N hydrochloric acid for 2h, pH 6.5 and pH 7.8 phosphate buffer solution for 12hr. Sodium carboxymethylcellulose showed above 95% release within 10 h where as carbopol-934P showed slow release about 88% to 92% over a period of 12 h. having excellent mucoadhesive strength but ethyl cellulose containing tablets showed less than 65% release. The release mechanism of all formulation was diffusion controlled confirmed from Higuchi's plot. Thus, the present study concluded that, carbopol-934P containing mucoadhesive tablets of omeprazole pellets can be used for local action in the ulcer disease as well as for oral controlled release drug delivery.

Cancer vaccines for non-small-cell lung cancer

Lung cancer is globally the second most common form of cancer in both men and women and the single largest cause of cancer-related mortality in the world. It is a disease with poor prognosis and the survival statistics have scarcely improved since historical times. The advent of targeted therapies has caused an incremental increase in survival figures. Nevertheless, significant progress in treatment outcomes need to be achieved before any perceptible improvement in overall survival of lung cancer patients becomes evident. The use of active-specific immunotherapy or cancer vaccines for the treatment of lung cancer is still in its infancy. Nevertheless several cancer vaccines have demonstrated clinical effects and improvements in overall survival in phase II and phase III trials and several more clinical trials are currently ongoing. This review summarizes the recent developments in NSCLC vaccines.

Development of a dendritic cell-based vaccine for chronic lymphocytic leukemia

Evidence for the existence of CLL-specific antigens recognized by the immune system can be gathered from the observation that many patients display monoclonal or oligoclonal expansions and skewed repertoire of T cells. In vitro functional studies have shown that tumor-specific T-cells are able to lyse the leukemic cells. Antileukemic cellular immunity may be boosted in vivo using dendritic cell-based immunotherapy. Our preclinical studies provide evidence that DC that had endocytosed apoptotic CLL cells (Apo-DC) were superior to fusion hybrids, tumor lysate or RNA in eliciting antileukemic T-cell responses in vitro. We have validated a method for enriching the small number of monocyte precursors present in the peripheral blood of CLL patients and utilize them for generating individualized, Apo-DC cellular vaccines. In most cases, a minimum of 50 x 10(6) Apo-DC could be generated, beginning with immunomagnetically enriched monocytes from a single leukapheresis product containing at least 1% CD14+ cells. Cryopreservation and thawing did not affect the phenotype or the T cell stimulatory function of Apo-DC. A phase I/II, open label clinical trial examining the feasibility, safety and immunogenicity of Apo-DC vaccination has been initiated. CLL patients receive 10(7) Apo-DC for at least five immunizations and monitored clinically and immunologically for 52 weeks. Three cohorts are accrued stepwise. Cohort I receives Apo-DC alone; Cohort II: Apo-DC+ repeated doses of low-dose GM-CSF; Cohort III: low-dose cyclophosphamide followed by Apo-DC + GM-CSF.

Diffuse retinal pigment epitheliopathy among the inhabitants of Brahmaputra Valley of India

PURPOSE

To analyze the patient demography and the various fluorescein angiography (FA) features of diffuse retinal pigment epitheliopathy (DRPE) cases among the inhabitants of the Brahmaputra Valley of India and to see if there is any ethnic variation in its clinical presentation and risk factors.

METHODS

This is a retrospective study in a clinical practice setting with study population of Aryan and Mongoloid races. Data analysis of 30 cases (40 eyes) of DRPE of 262 consecutive cases of central serous chorioretinopathy (CSC) was done. The various features of these cases were compared and statistically evaluated with the findings of CSC cases with symptom duration of 6 months or more and cases with recurrent episodes.

RESULTS

A total of 11.45% had DRPE that had average symptom duration of 3.50 years. Logistic regression showed high risk for DRPE if sensory retinal detachment (SRD) persists for more than 18 months. Systemic hypertension was another significant risk factor, whereas multiple RPE leaks appeared to be weakly significant. DRPE was predominant in eyes of patients having first acute episode of CSC in later age and fairly large retinal pigment epithelial detachments (PEDs) contributed to its development. Role of exogenous corticosteroid, retinotoxic drugs, and tobacco consumption could not be assessed properly due to inadequate sample size.

CONCLUSIONS

The main factor for the development of DRPE is the persistence of SRD for more than 1.50 years. Fairly large leaking PED and onset of primary CSC in later age appear to contribute towards its development. Except for these, no major variation from Western studies was observed.

Soluble CD40 ligand and atrial fibrillation: Relationship to platelet activation, and endothelial damage/dysfunction

Increased plasma soluble CD40L (sCD40L) is present in many cardiovascular diseases and predicts poor outcome, but levels in atrial fibrillation (AF) are unknown. Although the platelet is frequently cited as the source of sCD40L, this view is not universal. We hypothesised (a) raised sCD40L in non-rheumatic AF, and (b) that sCD40L correlates with platelet, but not endothelial, markers, thus suggesting a platelet origin. Plasma sCD40L, platelet marker soluble P-selectin and endothelial markers von Willebrand factor (vWf) and soluble E-selectin were measured by ELISA in 54 AF patients free of diabetes or major cardiovascular disease, and in 28 age/sex matched controls. Median (inter-quartile range) sCD40L in AF was 0.82 (0-4.8) ng/mL compared to 0.21 (0-5.5 ng/mL) in controls (p=0.0397). vWf and soluble P-selectin (p<0.005), but not soluble E-selectin, were raised in AF, but none of the indices inter-correlated significantly. We find that sCD40L is marginally raised in AF but the stimulus for this is unclear. The lack of clear correlation with relevant plasma markers suggests that the source is unlikely to be the endothelium or platelet alone.

Histological subclassification of cirrhosis based on histological-haemodynamic correlation

BACKGROUND

Determining a relationship between specific histological parameters in cirrhosis and hepatic venous pressure gradient can be used to subclassify cirrhosis.

AIM

To determine the relationship between hepatic venous pressure gradient and specific histological parameters in cirrhosis.

METHODS

Forty-seven patients (mean age: 46.2 +/- 13.6 years; 36 male) with biopsy-proven cirrhosis and hepatic venous pressure gradient measurements within 1 month of biopsy were studied. The following histological parameters were scored semiquantitatively: nodule size, loss of portal tracts and central veins, portal inflammation, periportal inflammation, bile duct proliferation, lobular inflammation, ballooning, fatty change, cholestasis and septal thickness.

RESULTS

On multiple ordinal regression analysis, small nodule size (odds ratio: 21.0; 95% confidence interval: 2.1-208.2, P = 0.009) and thick septa (OR: 42.6; CI: 2.3-783.7, P = 0.011) were significantly associated with the presence of clinically significant portal hypertension. A score was assigned to each of the two parameters (nodule size: large = 1, medium = 2, small = 3 and septal thickness: thin = 1, medium = 2, thick = 3). Two subcategories were devised based on the composite score: category A (n = 12): score 1-3 and category B (n = 35): score 4-6. On ordinal regression, subcategory B (OR: 15.5; CI: 3.3-74.2, P = 0.001) was significantly associated with clinically significant portal hypertension.

CONCLUSION

Small nodularity and thick septa are independent predictors of the presence of clinically significant portal hypertension.

Soluble CD40L, platelet surface CD40L and total platelet CD40L in congestive heart failure: relationship to platelet volume, mass and granularity

BACKGROUND

Many complications associated with congestive heart failure (CHF) have a thrombosis-related aetiology, which may involve platelets. The immune modulator pair CD40-CD40L has been proposed to be an important link between inflammation and thrombosis and may be important in the pathophysiology of CHF.

OBJECTIVE

To study soluble CD40L (sCD40L), platelet surface CD40L (%GCD40L) and total platelet CD40L (pCD40L) levels in CHF patients, their relationships to other platelet indices (platelet volume, mass and component) and to assess their prognostic value.

METHODS

We measured sCD40L (by ELISA); pCD40L (by a platelet lysate assay); platelet surface CD40L (%GCD40L) expression by flow cytometry; mean platelet volume (MPV), mean platelet mass (MPM) and mean platelet component (MPC); in 108 patients with stable CHF. Levels were compared with 37 'healthy controls' and 63 'disease controls'. After a median follow-up period of 490 days, clinical endpoints were determined.

RESULTS

pCD40L was significantly higher in CHF than disease controls, but not sCD40L or %GCD40L levels. CHF patients and disease controls had higher MPV (one-way anova, P < 0.0001), whilst MPC was significantly lower in CHF patients (P < 0.0001), compared to healthy controls. All indices related to CD40L (i.e. sCD40L, pCD40L and %GCD40L) were neither related to disease severity or left ventricular ejection function, nor to clinical endpoints at follow-ups.

CONCLUSION

Patients with stable CHF patients did not exhibit enhanced levels of CD40L and the latter did not predict clinical events at follow-up. The lack of difference in CD40L levels between CHF and disease controls suggests that CD40L may not have a major role in CHF per se, but in the comorbidities associated with CHF.