Generation and Evolution of High-Mach-Number Laser-Driven Magnetized Collisionless Shocks in the Laboratory

We present the first laboratory generation of high-Mach-number magnetized collisionless shocks created through the interaction of an expanding laser-driven plasma with a magnetized ambient plasma. Time-resolved, two-dimensional imaging of plasma density and magnetic fields shows the formation and evolution of a supercritical shock propagating at magnetosonic Mach number M_{ms}≈12. Particle-in-cell simulations constrained by experimental data further detail the shock formation and separate dynamics of the multi-ion-species ambient plasma. The results show that the shocks form on time scales as fast as one gyroperiod, aided by the efficient coupling of energy, and the generation of a magnetic barrier between the piston and ambient ions. The development of this experimental platform complements present remote sensing and spacecraft observations, and opens the way for controlled laboratory investigations of high-Mach number collisionless shocks, including the mechanisms and efficiency of particle acceleration.

Tolerance of weekly paclitaxel and carboplatin as neoadjuvant chemotherapy in advanced ovarian cancer patients who are unlikely to tolerate 3 weekly paclitaxel and carboplatin

OBJECTIVE

There are little data regarding safety and effectiveness of neoadjuvant chemotherapy (NACT) in patients who are considered unfit for receiving 3 weekly paclitaxel and carboplatin. The aim of this study was to study the toxicity and response rates of weekly paclitaxel and carboplatin as NACT in such cohort of patients.

METHODS

Study population included advanced ovarian cancer patients who were unlikely to tolerate 3 weekly paclitaxel and carboplatin and hence received weekly paclitaxel (80 mg/m2) and carboplatin AUC-2 as NACT. The data regarding the baseline characteristics, chemotherapy tolerance, completion rates, toxicity (CTCAE version 4.02), and radiological response rates are presented. SPSS version 16 was used for analysis. Descriptive statistics is presented.

RESULT

Eleven patients received this schedule. Nine patients completed nine cycles of NACT. Except one, all patients completed NACT with an average relative dose intensity of >0.8. There was no chemotherapy-related mortality. Grade 3-4 life-threatening complications were seen in two patients. The post NACT response rate was 100%.

CONCLUSION

Weekly paclitaxel and carboplatin chemotherapy is safe and efficacious in patients who are unsuitable for 3 weekly paclitaxel and carboplatin chemotherapy schedules.

An audit of cytoreductive surgeries in ovarian cancer from a rural based cancer center

BACKGROUND AND OBJECTIVE

Ovarian cancers are frequently seen at an advanced stage in our center. This audit was planned to see the morbidity and efficacy of different types of cytoreductive surgeries (radical vs. ultra-radical) done in such patients.

METHODS

This was a retrospective analysis of all ovarian cancer patients who underwent cytoreductive surgery at our center from January 2009 to August 2013. The case records of these patients were reviewed and the demographic, disease-related and treatment-related data were extracted.

RESULTS

Fifty-fivepatients were identified. Ten (18.2%) patients underwent primary cytoreduction while 45 patients had (81.8%) interval cytoreduction. The resections achieved were optimal in 50 patients (90.9%) and suboptimal in five patients (9.1%). The postoperative median blood loss was 400 (350-600) mL. The median time interval for surgery was 4.0 h (3-5 h). The type of resection achieved (optimal vs. suboptimal) was the only factor affecting the progression free survival (PFS) (Hazard ratio = 0.08 95% confidence interval 0.02-0.3). There was no significant difference in postoperative morbidity in patients undergoing the ultra-radical surgery as compared to those who underwent radical surgery.

CONCLUSION

Optimal cytoreduction may improve PFS in advanced ovarian cancer patients and needs to be done even if it mandates an ultra-radical surgery.

Development and validation of a questionnaire to measure preferences and expectations of patients undergoing palliative chemotherapy: EXPECT questionnaire

OBJECTIVE

The objective was to design and validate the questionnaire for capturing palliative chemotherapy-related preferences and expectations.

DESIGN

Single arm, unicentric, prospective observational study.

METHODS

EXPECT questionnaire was designed to capture preferences and expectations of patients undergoing palliative chemotherapy. This questionnaire underwent a linguistic validation and then was tested in patients. Ten patients are undergoing chemotherapy for solid tumors who fulfilled the inclusion and exclusion criteria self-administered the EXPECT questionnaire in regional language. After filling this questionnaire, they self-administered quick questionnaire-10 (QQ-10). SPSS version 16 (IBM New York) was used for analysis. Completion rate of EXPECT questionnaire was calculated. The feasibility, face validity, utility and time taken for completion of EXPECT questionnaire was also assessed.

RESULTS

The completion rate of this questionnaire was 100%. All patients completed questionnaire within 5 min. The QQ-10 tool confirmed the feasibility, face validity and utility of the questionnaire.

CONCLUSION

EXPECT questionnaire was validated in the regional language, and it's an effective tool for capturing patient's preferences and expectation from chemotherapy.

Predictivity of human papillomavirus positivity in advanced oral cancer

BACKGROUND AND OBJECTIVE

Human papillomavirus (HPV) is a known prognostic factor world over in patients of carcinoma oropharynx. The role of HPV in oral cancers has not been investigated adequately. We tried to identify standard clinicopathological features in oral cancer, which would predict HPV-positivity.

METHODS

This was a retrospective analysis of 124 cases of T4 oral cancer patients at our center. HPV-positive was defined in accordance with positive p16 immunohistochemistry done on pretreatment local tumor site biopsy. Age, sex, habits (smoking history and oral tobacco), Eastern Cooperative Oncology Group performance status (ECOG PS), T stage, N stage, grade, and site were selected, for testing of prediction for HPV-positivity. The analysis was performed by R studio version 3.1.1. Two-sample test for equality of proportions with continuity correction was used to identify factors predicting for HPV-positivity. P = 0.05 was considered as significant.

RESULTS

Of 124 patients, 16 patients (12.9%) were HPV-positive. The median age of the whole cohort was 43 years (interquartile range 37-52 years) with 15 females (12.1%). All had squamous cell carcinoma (100%). The grade of the tumor was well differentiated in 9 patients (7.2%), moderately differentiated in 98 patients (79.1%), and poorly differentiated in 17 patients (13.7%). The ECOG PS 0 in 19 patients (15.3%), 1 in 104 patients (83.9%), and 2 in 1 patient (0.8%). The subsite of the tumor was buccal mucosa in 74 patients (59.7%), anterior two-third of tongue in 33 patients (26.6%), and others in 17 patients (13.7%). None of the tested factors except the use of oral tobacco were statistically significantly associated with HPV-positivity. History of tobacco usage had a statistical trend toward ability to predict HPV-positivity. The proportion of patients with HPV-positive oral cancer in patients without history usage of oral tobacco was 31.3% while it was 10.2% in patients with previous history of tobacco use (P = 0.03).

CONCLUSION

Standard clinicopathological variables could not predict for HPV-positivity. Negative history of tobacco (smokeless) usage showed statistical trends toward ability to predict HPV-positivity in oral cancer patients.

Head and neck cancer in geriatric patients: Analysis of the pattern of care given at a tertiary cancer care center

BACKGROUND AND AIM

The percentage of elderly people with head and neck cancers (HNC) is on the rise. This makes HNC in this group of patients an important issue for healthcare providers. The present study was planned to analyze the patterns of care given to the geriatric patients and to identify the factors influencing the decision making process.

MATERIALS AND METHODS

Data of all the elderly patients (≥65 years) registered in the year 2012, with histologically proven HNC (all sites, stages, histopathological types, except lymphoma, sarcoma and cervical metastasis of unknown origin) receiving treatment (definitive/palliative) were collected.

RESULTS

A total of 270 patients were included in this study. The median age was 72 years (range: 65-101), with predominant male population (70%, n = 190). Oral cavity squamous cell carcinoma (SCC) was the most common cancer (57%, n = 154). Eastern Co-Operative Oncology Group performance status (PS) of 0-2 was seen in 91% of the patients. Co-morbidities were present in 139 (51.5%) patients. 50% (n = 134) of the patients received palliative intent treatment, 45% (n = 123) definitive treatment, whereas in 5% (n = 13) the intent was not mentioned. Age, a clinical stage and PS significantly influenced the decision making on the intent of treatment. 208 (77%) patients completed their treatment irrespective of the intent. Age was the only factor influencing treatment completion irrespective of the intent.

CONCLUSION

Geriatric HNC patients frequently present with advanced disease, having multiple co-morbidities. Hence, a multidisciplinary team management of these patients is essential, also taking into account of the social and financial support available to these patients.

Is taxane/platinum/5 fluorouracil superior to taxane/platinum alone and does docetaxel trump paclitaxel in induction therapy for locally advanced oral cavity cancers?

BACKGROUND

Cisplatin and 5 fluorouracil drug combination is inferior to the combination of taxane with these 2 drugs. However, often in clinical practice at our center giving TPF (docetaxel, cisplatin, 5 fluorouracil) is difficult in view of logistics and tolerance issues. In such a scenario, we prefer to use the 2 drugs combination of platinum and taxane. However, no study has addressed whether a 2 drugs combination, which includes taxane is inferior to the 3 drugs combination and which the taxane of choice is in the 2 drugs combination of taxane and platinum.

METHODS

This is a retrospective analysis of prospectively collected data of patients undergoing induction chemotherapy (IC) in oral cavity cancers from 2010 to 2012. We chose for analysis those patients who had a baseline scan done within 4 weeks of starting therapy and a follow-up scan done within 2 weeks of completion of the second cycle of IC. Response was scored in accordance with RECIST version 1.1. Chi-square analysis was done to compare response rates (RRs) between regimens.

RESULTS

Two hundred and forty-five patients were identified. The median age was 45 years (24-70 years), 208 (84.9%) were male patients, and 154 patients (62.9%) had primary in the Buccal mucosa. The regimens received were TPF 22 (9%), docetaxel + cisplatin 97 (39.6%), paclitaxel + cisplatin 89 (36.3%), docetaxel + carboplatin 16 (6.5%) and paclitaxel + carboplatin 21 (8.6%). The overall RRs were complete response, partial response, stable disease and progressive disease in 4 (1.6%), 56 (22.9%), 145 (59.2%) and 40 (16.3%). The 3 drugs regimen (TPF) had 50% RR as compared to 22% RR with 2 drugs regimen (P = 0.004). Docetaxel containing regimens had 30.3% RR as compared to 17.2% RR with paclitaxel containing regimens (P = 0.094).

CONCLUSIONS

TPF has better RR than a 2 drugs taxane-containing regimen and docetaxel leads to a better RR than paclitaxel for IC in locally advanced oral cavity cancers.

The in vivo significance of antibiotic-induced endotoxin release in experimental Gram-negative sepsis

Considerable evidence now supports the experimental findings that penicillin-binding protein (PBP)-2 specific antimicrobial agents such as imipenem generate less endotoxin than PBP-3 specific agents such as ceftazidime during the process of bacteriolysis of Gram-negative bacteria. To determine if differences in endotoxin release have pathophysiologic significance in vivo, Sprague-Dawley rats were experimentally challenged with intraperitoneal injections of virulent, serum-resistant clinical strains of the following Gram-negative bacilli: Escherichia coli 018:K1, Klebsiella pneumoniae K2, and Pseudomonas aeruginosa 12.4.4 (immuno type 6). After intravenous administration of imipenem (25 mg/kg), ceftazidime (50 mg/kg) or saline control, imipenem and ceftazidime-treated animals had rapid reductions in the quantitative level of bacteremia from all three pathogens. Peritoneal fluid samples revealed spherical forms with imipenem and long, filamentous forms with ceftazidime. Circulating plasma endotoxin levels were consistently higher ( P < 0.05) with ceftazidime than imipenem for 6 h after administration of E. coli or P. aeruginosa intraperitoneal challenge. Endotoxin levels were unchanged to slightly higher with imipenem than ceftazidime following K. pneumoniae intraperitoneal challenge. TNF levels peaked 2 h post-therapy and were consistently higher with ceftazidime-treated animals ( P < 0.05). D-galactosamine-treated animals had LD50 values that were 0.5-2 log higher ( P < 0.001) with imipenem for E. coli and P. aeruginosa but did not differ from ceftazidime in animals challenged with the K. pneumoniae strain. These results indicate that the PBP-2 specific agent imipenem led to significantly less endotoxin release than did ceftazidime with its great affinity to PBP-3. Differential endotoxin release was found after antimicrobial therapy with the E. coli and P. aeruginosa strains but not with the K. pneumoniae strain tested in this study. The clinical relevance of these findings with treatment of systemic Gram-negative infections in humans will require further clinical investigation.

Tolerance of weekly metronomic paclitaxel and carboplatin as neoadjuvant chemotherapy in advanced ovarian cancer patients who are unlikely to tolerate 3 weekly paclitaxel and carboplatin

OBJECTIVE

There are little data regarding safety and effectiveness of neoadjuvant chemotherapy (NACT) in patients who are considered unfit for receiving 3 weekly paclitaxel and carboplatin. The aim of this study was to examine the toxicity and response rates of weekly paclitaxel and carboplatin as NACT in such cohort of patients.

METHODS

Study population included advanced ovarian cancer patients who were unlikely to tolerate 3 weekly paclitaxel and carboplatin and hence received weekly paclitaxel (80 mg/m(2)) and carboplatin AUC-2 as NACT. The data regarding the baseline characteristics, chemotherapy tolerance, completion rates, toxicity (Common Terminology Criteria for Adverse Events version 4.02), and radiological response rates are presented. SPSS version 16 was used for analysis. Descriptive statistics is presented.

RESULTS

Eleven patients received this schedule. Nine patients completed nine cycles of NACT. Except one, all patients completed NACT with an average relative dose intensity of >0.8. There was no chemotherapy-related mortality. Grade 3-4 life-threatening complications were seen in two patients. The post NACT response rate was 100%.

CONCLUSIONS

Weekly paclitaxel and carboplatin chemotherapy is safe and efficacious in patients who are unsuitable for 3 weekly paclitaxel and carboplatin chemotherapy schedules.

Molecular docking of the anticancer bioactive compound proceraside with macromolecules involved in the cell cycle and DNA replication

The bioactive compounds proceraside A, frugoside and calotropin, which were extracted from the root bark of Calotropis procera (Aiton) W.T. Aiton (family Asclepiadaceae), were recently reported to inhibit the growth of inhibition against various human cancer cell lines in vitro. However, their modes of action have not been clearly defined. Therefore, we attempted an in silico approach to gain insights into their binding modes against the following selected molecular targets: CDK-2, CDK-6, topoisomerase I, BCL-2, VEGFR-2, telomere: G-quadruplex, and topoisomerase II. These targets were selected based on their key roles in cancer progression via the regulation of the cell cycle and DNA replication. Molecular-docking analyses revealed that proceraside A was the best docked ligand against all the targets, with the exception of telomere-G: quadruplex. Furthermore, it displayed the lowest binding energies and inhibition constants, and critical hydrogen bonds and hydrophobic interactions with the targets were also revealed. The present study may aid in the identification of possible targets for proceraside A, and might provide a plausible explanation for its proven anti-tumor activities. Moreover, the result of this study may further guide structure-activity relationship studies used to generate more potent target-specific inhibitors.

Contribution of efflux pumps in fluroquinolone resistance in multi-drug resistant nosocomial isolates of Pseudomanas aeruginosa from a tertiary referral hospital in north east India

BACKGROUND

Pseudomonas aeruginosa is one of the leading opportunistic pathogen and its ability to acquire resistance against series of antimicrobial agents confine treatment option for nosocomial infections. Increasing resistance to fluroquinolone (FQ) agents has further worsened the scenario. The major mechanism of resistance to FQs includes mutation in FQs target genes in bacteria (DNA gyrase and/or topoisomerases) and overexpression of antibiotic efflux pumps.

OBJECTIVE

We have investigated the role of efflux pump mediated FQ resistance in nosocomial isolates of P. aeruginosa from a tertiary referral hospital in north eastern part of India.

MATERIALS AND METHODS

A total of 234 non-duplicate, consecutive clinical isolates of P. aeruginosa were obtained from a tertiary referral hospital of north-east India. An efflux pump inhibitor (EPI), carbonyl cyanide m-chlorophenylhydrazone (CCCP) based method was used for determination of efflux pump activity and multiplex polymerase chain reaction (PCR) was performed for molecular characterisation of efflux pump. Minimum inhibitory concentration (MIC) reduction assay was also performed for all the isolates.

RESULTS AND CONCLUSION

A total number of 56 (23%) have shown efflux mediated FQ resistance. MexAB-OprM efflux system was predominant type. This is the first report of efflux pump mediated FQ resistance from this part of the world and the continued emergence of these mutants with such high MIC range from this part of the world demands serious awareness, diagnostic intervention, and proper therapeutic option.

Formation of current singularity in a topologically constrained plasma

Recently a variational integrator for ideal magnetohydrodynamics in Lagrangian labeling has been developed. Its built-in frozen-in equation makes it optimal for studying current sheet formation. We use this scheme to study the Hahm-Kulsrud-Taylor problem, which considers the response of a 2D plasma magnetized by a sheared field under sinusoidal boundary forcing. We obtain an equilibrium solution that preserves the magnetic topology of the initial field exactly, with a fluid mapping that is non-differentiable. Unlike previous studies that examine the current density output, we identify a singular current sheet from the fluid mapping. These results are benchmarked with a constrained Grad-Shafranov solver. The same signature of current singularity can be found in other cases with more complex magnetic topologies.

Binding of small molecules at interface of protein-protein complex - A newer approach to rational drug design

Protein–protein interaction is a vital process which drives many important physiological processes in the cell and has also been implicated in several diseases. Though the protein–protein interaction network is quite complex but understanding its interacting partners using both in silico as well as molecular biology techniques can provide better insights for targeting such interactions. Targeting protein–protein interaction with small molecules is a challenging task because of druggability issues. Nevertheless, several studies on the kinetics as well as thermodynamic properties of protein–protein interactions have immensely contributed toward better understanding of the affinity of these complexes. But, more recent studies on hot spots and interface residues have opened up new avenues in the drug discovery process. This approach has been used in the design of hot spot based modulators targeting protein–protein interaction with the objective of normalizing such interactions.