Blazar spectral variability as explained by a twisted inhomogeneous jet

Blazars are active galactic nuclei, which are powerful sources of radiation whose central engine is located in the core of the host galaxy. Blazar emission is dominated by non-thermal radiation from a jet that moves relativistically towards us, and therefore undergoes Doppler beaming. This beaming causes flux enhancement and contraction of the variability timescales, so that most blazars appear as luminous sources characterized by noticeable and fast changes in brightness at all frequencies. The mechanism that produces this unpredictable variability is under debate, but proposed mechanisms include injection, acceleration and cooling of particles, with possible intervention of shock waves or turbulence. Changes in the viewing angle of the observed emitting knots or jet regions have also been suggested as an explanation of flaring events and can also explain specific properties of blazar emission, such as intra-day variability, quasi-periodicity and the delay of radio flux variations relative to optical changes. Such a geometric interpretation, however, is not universally accepted because alternative explanations based on changes in physical conditions-such as the size and speed of the emitting zone, the magnetic field, the number of emitting particles and their energy distribution-can explain snapshots of the spectral behaviour of blazars in many cases. Here we report the results of optical-to-radio-wavelength monitoring of the blazar CTA 102 and show that the observed long-term trends of the flux and spectral variability are best explained by an inhomogeneous, curved jet that undergoes changes in orientation over time. We propose that magnetohydrodynamic instabilities or rotation of the twisted jet cause different jet regions to change their orientation and hence their relative Doppler factors. In particular, the extreme optical outburst of 2016-2017 (brightness increase of six magnitudes) occurred when the corresponding emitting region had a small viewing angle. The agreement between observations and theoretical predictions can be seen as further validation of the relativistic beaming theory.

Molecular basis for the methylation specificity of ATXR5 for histone H3

In plants, the histone H3.1 lysine 27 (H3K27) mono-methyltransferases ARABIDOPSIS TRITHORAX RELATED PROTEIN 5 and 6 (ATXR5/6) regulate heterochromatic DNA replication and genome stability. Our initial studies showed that ATXR5/6 discriminate between histone H3 variants and preferentially methylate K27 on H3.1. In this study, we report three regulatory mechanisms contributing to the specificity of ATXR5/6. First, we show that ATXR5 preferentially methylates the R/F-K*-S/C-G/A-P/C motif with striking preference for hydrophobic and aromatic residues in positions flanking this core of five amino acids. Second, we demonstrate that post-transcriptional modifications of residues neighboring K27 that are typically associated with actively transcribed chromatin are detrimental to ATXR5 activity. Third, we show that ATXR5 PHD domain employs a narrow binding pocket to selectively recognize unmethylated K4 of histone H3. Finally, we demonstrate that deletion or mutation of the PHD domain reduces the catalytic efficiency (k_cat/K_m of AdoMet) of ATXR5 up to 58-fold, highlighting the multifunctional nature of ATXR5 PHD domain. Overall, our results suggest that several molecular determinants regulate ATXR5/6 methyltransferase activity and epigenetic inheritance of H3.1 K27me1 mark in plants.

An Update of Patents, Preclinical and Clinical Outcomes of Lipid Nanoparticulate Systems

BACKGROUND

Lipid nanoparticles have attracted increased degree of scientific and commercial attention in the last decade. The lipidic nanoparticles have emerged as a potential alternative to other nano-scale systems due to their various advantages over them and also due to overcoming the shortcomings of the already available colloidal systems like liposomes, niosomes and polymeric nanoparticles.

DESCRIPTION

These have been investigated for delivery of macromolecules, genes, siRNA and other therapeutic agents for oral, topical, parenteral administration and target site specific delivery for various diseases like cancer, ocular diseases and brain disorders. The lipid nanoparticles have evolved from SLNs, then NLCs and lipid drug conjugates overcoming any issues related to production and formulation and adding advantages, if any. The current review article focuses on the lipid nanoparticles, their formulation approaches and current advancements in the field through recent clinical trials and patents. This manuscript embodies various patents, preclinical and clinical aspects related to the lipidic nanocarriers.

CONCLUSION

Over the years the lipidic nanoparticulate systems have evolved as significant carriers for improved therapeutics and in diagnostic field. The large number of patents and preclinical trials in the recent years suggests that these systems will find immense potential in near future.

Effect of creative writing on mood in cancer patients

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Background: Patients with cancer may have significant mental health comorbidity. Creative writing has a substantial history in providing a wide range of psychological benefits for cancer patients. Methods: We conducted a pilot study to determine feasibility whether cancer patients can be enrolled, randomized and retained for four weeks for creative writing classes (Feasibility was defined as 50% of our enrolled patients on intervention arm (IA) could attend at least 2 classes). We anticipated enrolling 45 patients over the period of 2 months with randomization into 2 arms: IA and standard of care (SOC). “Write from the Heart”, a series of creative writing workshops (CWW) were conducted on IA. Subjects in IA had four, 2-hour weekly CWW whereas SOC arm did not receive any sessions. We used validated Emotional Thermometer Scales (ETS), ranging from 0 (best)-10 (worst), to predict changes in parameters reflecting patient’s mental health pre and post intervention. ETS has five dimensions (distress, anxiety, depression, anger and need help), which are all continuous variables. Results: Total of 16 patients were accrued -11 in IA and 5 in SOC. 7 out of 11 (63%) patients enrolled in IA attended at least 75% of classes. Comparisons were made using two-sample T-tests. Although sample size was small, analysis showed intriguing results. IA did show a decreasing pattern on Total Emotion Score (TES). For each visit, post-class scores were lower than pre-class scores. SOC versus IA and IA intragroup analysis (Paired T-test) did not reveal any statistical significance. Conclusions: We observed that it is feasible for cancer patients to attend focused workshops geared towards mental health wellbeing. Although not statistically significant, IA showed trend towards mood improvement. A second study is planned with a single arm for all cancer patients. In addition to using emotional thermometers, we will include questionnaires to evaluate mental health symptoms effectively. Further prospective clinical studies should be conducted to evaluate effect of this intervention in cancer patients. Clinical trial information: Study 00006541. [Table: see text]

Deposition and spatial variation of thoron decay products in a thoron experimental house using the Direct Thoron Progeny Sensors

Experiments have been carried out using the deposition-based Direct Thoron Progeny Sensors (DTPS) in a thoron experimental house. The objective was to study the thoron decay product characteristics such as the deposition velocities, spatial variability and dependence on aerosol particle concentrations. Since the deposition velocity is an important characteristic in the calibration of the DTPS, it is very important to study its dependence on aerosol concentration in a controlled environment. At low aerosol concentration (1500 particles/cm³) the mean effective deposition velocity was measured to be 0.159 ± 0.045 m h^-1; at high aerosol concentration (30 000 particles/cm³) it decreased to 0.079 ± 0.009 m h^-1. The deposition velocity for the attached fraction of the thoron decay products did not change with increasing aerosol concentration, showing measurement results of 0.048 ± 0.005 m h^-1 and 0.043 ± 0.014 m h^-1, respectively. At low particle concentration, the effective deposition velocity showed large scattering within the room at different distances from center. The attached fraction deposition velocity remained uniform at different distances from the wall. The measurements in the thoron experimental house can be used as a sensitivity test of the DTPS in an indoor environment with changing aerosol concentration. The uniform spatial distribution of thoron decay products was confirmed within the experimental house. This indicates that direct measurement of thoron decay product concentration should be carried out instead of inferring it from thoron gas concentration, which is very inhomogeneous within the experimental house.

ATM/RB1 mutations to predict shorter overall survival (OS) in bladder cancer

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Background: DNA repair defect plays an important role in tumorigenesis, progression and treatment outcomes of urothelial cancer. Somatic mutations of ATM/RB1 genes are frequently found in urothelial cancer and have been associated with a better response to cisplatin-based neoadjuvant chemotherapy. However, their prognostic value overall in urothelial cancer have not been determined. Methods: Exome sequencing data of 130 urothelial bladder cancer patients (pts) from The Cancer Genome Atlas (TCGA) dataset were analyzed as a discovery cohort to determine the prognostic value of ATM and RB1 mutations. Results from discovery dataset were further validated by an independent cohort of 79 advanced urothelial cancer pts who received comprehensive genomic sequencing for urothelial cancer with FoundationOne. OS was measured from time of initial diagnosis and Cox proportional hazard regression analysis was performed to calculate the hazard ratio (HR) and 95% confidence interval (CI). Results: In the discovery dataset, somatic mutations of ATM/RB1 genes were present in 24% of pts and were associated with significantly shorter OS [all stages: adjusted HR = 2.67, 95% CI, 1.45–4.92, P = 0.002; stage II-III only: adjHR = 2.76, 95% CI, 1.23–6.20, P = 0.014]. There was high mutation load in pts carrying ATM/RB1 mutations (median mutation count: 196 versus 160, P = 0.09). In the validation (stage IV) dataset, ATM/RB1 mutations were present in 31.7% of pts and tended to associate with shorter OS (adjHR = 1.97, 95% CI, 0.89–4.40, P = 0.094) and higher mutation load (median mutation load: 8.1 versus 7.2 per Mb, P = 0.136), although statistical significance was not reached. Conclusions: These results suggest that ATM/RB1 mutations may be considered as a poor prognostic biomarker in unselected urothelial cancer pts and may correlate with higher mutational load. Further studies are required to determine patient characteristics that can further stratify prognosis based on ATM/RB1 mutation status, and evaluate the potential predictive role of ATM/RB1 mutation status in response to immunotherapy.

Spectrum of tumor mutational load (TML) in genitourinary cancers (GU CA)

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Background: Immunotherapy (IO) is now standard of care for bladder and kidney cancer (CA) and is investigational in other GU CA such as prostate and germ cell CA. Tumor mutational load (TML) has correlated with response to IO in several tumor types. Herein, we explore TML across different histological subtypes in GU CA. In addition, we also assess the correlation between TML and PD-L1 status. Methods: 544 GU specimens were identified: bladder, 145; kidney, 164; prostate, 221; penile, 2; testicular, 12. TML was calculated using somatic non-synonymous missense mutations from a 592-gene panel (Illumina NextSeq). A high TML was > 17 mutations/MB. PD-L1 (SP142) was done depending tumor availability. Results: High TML was more prevalent in bladder CA (14.5%, 21/145) compared to other GU CA. Urothelial carcinomas had a noticeably high TML while squamous histology had a pronounced PD-L1 expression (Figure 1). A comparison of TML-high (n=15) versus TML-low (n=76) urothelial bladder CA showed the following differences (Figure 2). TML was rare in kidney CA (1.8%, 1/57); PD-L1 was high in sarcomatoid (33.3%, 5/15), CDC/RMC (28.6%, 2/7). Prostate adenocarcinoma had few TML-high (2.3%, 5/219) or PD-L1 expressing tumors (1.4%, 3/208). Tumors of penile or testicular origin lacked high TML and PD-L1 expression. No correlation was found between a high TML and PD-L1 expression. Conclusions: TML varied considerably amongst GU CA. As in other CA, TML-high scores did not predict PD-L1 expression and vice versa. Comprehension of the underlying biology may assist in determining which CA may respond better to IO. [Table: see text]

[Table: see text]

Spotlight on nivolumab in the treatment of renal cell carcinoma: design, development, and place in therapy

Several tyrosine kinase inhibitors targeting the vascular endothelial growth factor receptors and molecules inhibiting the mammalian target of rapamycin are being used for management of metastatic renal cell carcinoma (mRCC); however, there is still a potential for improvement. Immune checkpoint inhibitors like nivolumab and other PD-1/PD-L1 inhibitors provide an alternative approach for patients with mRCC. In this article, the authors review the safety profile and outcomes of phase 1, 2, and 3 clinical trials of nivolumab in mRCC.

ATM/RB1 mutations to predict shorter overall survival (OS) in bladder cancer

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Background: DNA repair defect plays an important role in tumorigenesis, progression and treatment outcomes of urothelial cancer. Somatic mutations of ATM/RB1 genes are frequently found in urothelial cancer and have been associated with a better response to cisplatin-based neoadjuvant chemotherapy. However, their prognostic value overall in urothelial cancer have not been determined. Methods: Exome sequencing data of 130 urothelial bladder cancer patients (pts) from The Cancer Genome Atlas (TCGA) dataset were analyzed as a discovery cohort to determine the prognostic value of ATM and RB1 mutations. Results from discovery dataset were further validated by an independent cohort of 79 advanced urothelial cancer pts who received comprehensive genomic sequencing for urothelial cancer with FoundationOne. OS was measured from time of initial diagnosis and Cox proportional hazard regression analysis was performed to calculate the hazard ratio (HR) and 95% confidence interval (CI). Results: In the discovery dataset, somatic mutations of ATM/RB1 genes were present in 24% of pts and were associated with significantly shorter OS [all stages: adjusted HR = 2.67, 95% CI, 1.45–4.92, P = 0.002; stage II-III only: adjHR = 2.76, 95% CI, 1.23–6.20, P = 0.014]. There was high mutation load in pts carrying ATM/RB1 mutations (median mutation count: 196 versus 160, P = 0.09). In the validation (stage IV) dataset, ATM/RB1 mutations were present in 31.7% of pts and tended to associate with shorter OS (adjHR = 1.97, 95% CI, 0.89–4.40, P = 0.094) and higher mutation load (median mutation load: 8.1 versus 7.2 per Mb, P = 0.136), although statistical significance was not reached. Conclusions: These results suggest that ATM/RB1 mutations may be considered as a poor prognostic biomarker in unselected urothelial cancer pts and may correlate with higher mutational load. Further studies are required to determine patient characteristics that can further stratify prognosis based on ATM/RB1 mutation status, and evaluate the potential predictive role of ATM/RB1 mutation status in response to immunotherapy.

Effectiveness of amitriptyline and lamotrigine in traumatic spinal cord injury-induced neuropathic pain: a randomized longitudinal comparative study

STUDY DESIGN

Randomized longitudinal comparative study.

OBJECTIVES

To compare the efficacy of lamotrigine and amitriptyline in the management of traumatic spinal cord injury (SCI)-induced neuropathic pain (NP).

SETTING

Sawai Man Singh Medical College and Hospital, Jaipur, India.

METHODS

A total of 147 individuals with NP were randomized for a 3-week trial of either amitriptyline or lamotrigine. Amitriptyline was administered orally at doses of 25, 50 and 100 mg once daily at night time, and lamotrigine was administered orally at doses of 25, 50 and 100 mg twice daily, both for 1 week by means of optional titration. Assessment of NP was done at baseline and thereafter at 1, 2 and 3 weeks using Short-form MC Gill Pain Questionnaire-2 (SFMPQ2) scores.

RESULTS

There was a significant difference between the mean values of the SFMPQ2 score at baseline and those at each follow-up for amitriptyline. Similar results were seen in the lamotrigine group. When the differences in mean SFMPQ2 scores at different time frames from baseline were compared with those of the other group, values were found to be nonsignificant as seen on the Mann-Whitney U-test.

CONCLUSIONS

These findings support the use of both amitriptyline and lamotrigine in the management of NP after traumatic SCI.

Relationship of smoking status to genomic profile, chemotherapy response and clinical outcome in patients with advanced urothelial carcinoma

Smoking has been linked to urothelial carcinoma (UC), but the implications on genomic profile and therapeutic response are poorly understood. To determine how smoking history impacts genomic profile and chemotherapy response, clinicopathologic data was collected for patients with metastatic UC (mUC) across 3 academic medical centers and comprehensive genomic profiling (CGP) was performed through a CLIA-certified lab. Unsupervised hierarchical clustering based on smoking status was used to categorize the frequency of genomic alterations (GAs) amongst current smokers (CS), ex-smokers (ES) and non-smokers (NS), and survival was compared in these subsets. Fisher's exact test identified significant associations between GAs and smoking status. Amongst 83 patients, 23%, 55% and 22% were CS, ES, and NS, respectively, and 95% of patients had stage IV disease. With a median follow up of 14.4 months, the median overall survival (OS) was significantly higher in NS and ES (combined) as compared to CS (51.6 vs 15.6 months; P = 0.04). Of 315 cancer-related genes and 31 genes often related to rearrangement tested, heatmaps show some variations amongst the subsets. GAs in NSD1 were more frequent in CS as compared to other groups (P < 0.001). CS status negatively impacts OS in patients with mUC and is associated with genomic alterations that could have therapeutic implications.

Molecular Characterization of Bladder Cancer in Smokers versus Nonsmokers

Smoking is considered an important risk factor for bladder cancer (BC), yet molecular characterization of BC in nonsmokers has not been extensively studied. Here, we compare molecular differences between smokers and nonsmokers with BC. BC specimens (676) profiled at a Clinical Laboratory Improvement Amendments-certified laboratory from 2006 to 2014 were retrospectively evaluated for molecular differences between smokers and nonsmokers. Protein expression was determined with immunohistochemistry. In situ hybridization was used for ERBB2 (HER2/neu) and EGFR evaluation. Genes were evaluated using Sanger or next-generation sequencing. Thirty patients were confirmed lifetime nonsmokers (NS) and 39 were reformed or current smokers (RCS). There was a trend for increased PIK3CA mutations in NS versus RCS (43% vs 11%, p=0.1760), whereas TP53 alterations were higher in RCS versus NS (63% vs 53%, p=0.6699). EGFR amplification was observed more in NS versus RCS (22% vs 11%, p=0.5815), while HER2 was amplified only in RCS (23% vs 0%, p=0.05). The molecular differences between RCS and NS with BC suggest a different oncogenesis with potentially different treatment options.

PATIENT SUMMARY

Bladder cancer patients with no history of smoking have different molecular characteristics than those with smoking history. We found that smokers tend to have higher incidence of HER2 amplification, whereas nonsmokers seemed to have higher PIK3CA mutation. This knowledge provides essential information, which can bear relevance to treatment options.

Neoadjuvant Chemotherapy for Muscle-Invasive Bladder Cancer: A Systematic Review and Two-Step Meta-Analysis

BACKGROUND

Platinum-based neoadjuvant chemotherapy has been shown to improve survival outcomes in muscle-invasive bladder cancer patients. We performed a systematic review and meta-analysis to provide updated results of previous findings. We also summarized published data to compare clinical outcomes of methotrexate, vinblastine, doxorubicin, and cisplatin (MVAC) versus gemcitabine and cisplatin/carboplatin (GC) in the neoadjuvant setting.

METHODS

A meta-analysis of 15 randomized clinical trials was performed to compare neoadjuvant chemotherapy plus local treatment with the same local treatment alone. Because no randomized trials have investigated MVAC versus GC in the neoadjuvant setting, a meta-analysis of 13 retrospective studies was performed to compare MVAC with GC.

RESULTS

A total of 3,285 patients were included in 15 randomized clinical trials. There was a significant overall survival (OS) benefit associated with cisplatin-based neoadjuvant chemotherapy (hazard ratio [HR], 0.87; 95% confidence interval [CI], 0.79-0.96). A total of 1,766 patients were included in 13 retrospective studies. There was no significant difference in pathological complete response between MVAC and GC. However, GC was associated with a significantly reduced overall survival (HR, 1.26; 95% CI, 1.01-1.57). After excluding carboplatin data, GC still seemed to be inferior to MVAC in OS (HR, 1.31; 95% CI, 0.99-1.74), but the difference was no longer statistically significant.

CONCLUSION

These results support the use of cisplatin-based combination neoadjuvant chemotherapy in muscle-invasive bladder cancer. Although GC and MVAC had similar treatment response rates, the different survival outcome observed in this study requires further investigation.

IMPLICATIONS FOR PRACTICE

Platinum-based neoadjuvant chemotherapy (NCT) has been shown to improve survival outcomes in muscle-invasive bladder cancer (MIBC) patients, but the optimal neoadjuvant regimen has not been established. Methotrexate, vinblastine, doxorubicin, and cisplatin (MVAC) and gemcitabine and cisplatin/carboplatin (GC) are two of the most commonly used chemotherapy regimens in modern oncology. In this two-step meta-analysis, an updated and more precise estimate of the survival benefit of cisplatin-based NCT in MIBC is provided. This study also demonstrated that MVAC might have superior overall survival compared with GC (with or without carboplatin data) in the neoadjuvant setting. The findings suggest that NCT should be standard care in MIBC, and MVAC could be the preferred neoadjuvant regimen.

Novel approaches in cancer immunotherapy -- a light at the end of the tunnel

After decades of disappointments, the use of immunotherapy in cancer has finally come of age and resulted in a real paradigm shift in cancer treatment across many tumor types. With the advent of novel immunotherapies based on increasing understanding of the human immune system, cure has become a real possibility for many patients. The development of cancer vaccines, immune checkpoint inhibitors, chimeric antigen receptor T cell, oncolytic virus based immunotherapy to name a few have given hope to patients. One of the most exciting developments in the era of immunotherapy has been the discovery of checkpoint inhibitors causing blockade of two important immune pathways -- cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) and programmed death receptor-1 (PD-1), resulting in empowerment of anti-tumor immunity. However, only a select group of patients respond to these immunotherapies, highlighting a need for novel strategies that could help transform the non-responders to responders' category. This article highlights various immunotherapeutic agents and strategies using them and other modalities in the treatment of solid tumors.