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Khan MH, Unnikrishnan S, Ramalingam K. Antipathogenic Efficacy of Biogenic Silver Nanoparticles and Antibiofilm Activities Against Multi-drug-Resistant ESKAPE Pathogens. Appl Biochem Biotechnol 2024; 196:2031-2052. [PMID: 37462813 DOI: 10.1007/s12010-023-04630-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/01/2023] [Indexed: 04/23/2024]
Abstract
The silver nanoparticles (AgNPs) were produced by employing a biogenic loom and tested for antipathogenic assets against multi-drug-resistant (MDR) ESKAPE bacteria. Biogenically synthesized AgNPs were characterized adopting various high-throughput techniques such as UHRTEM, SEM with EDX, DLS, TGA-DTA, and XRD and spectroscopic analysis showed polydispersion of nanoparticles. In this context, AgNPs with the attribute of spherical-shaped nanoparticles with an average size of 26 nm were successfully synthesized utilizing bacterial supernatant. The antipathogenic activities of AgNPs were assessed against 11 strains of MDR ESKAPE bacteria including Enterococcus faecium; methicillin-resistant Staphylococcus aureus; Klebsiella pneumonia; Acinetobacter baumannii; Pseudomonas aeruginosa; Enterobacter aerogenes; and Enterobacter species. The exposure of biogenic AgNPs in a well diffusion assay showed all the growth inhibitions of ESKAPE bacteria at 200 μg/ml after 18 h of incubation. Growth kinetics demonstrated maximum killing at 60 μg/ml after 4 h of completion. The highest biofilm depletions were found at 100 μg/ml in adhesion assay. Live/dead assays showed effective killing of the ESKAPE bacteria at 10 μg/ml in pre-existing biofilms. The effective inhibitory concentrations of AgNPs were investigated ranging from 10 to 200 μg/ml. The selected pathogens found sensitive to AgNPs are statistically significant (P < 0.05) than that of cefotaxime/AgNO3. Consequently, a broad spectrum of antimicrobial potentials of AgNPs can be alternative to conventional antimicrobial agents for future medicine.
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Affiliation(s)
- Mohd Hashim Khan
- School of Life Sciences, B.S. Abdur Rahman Crescent Institute of Science and Technology, GST Road, Vandalur, Chennai, Tamil Nadu, 600 048, India
| | - Sneha Unnikrishnan
- School of Life Sciences, B.S. Abdur Rahman Crescent Institute of Science and Technology, GST Road, Vandalur, Chennai, Tamil Nadu, 600 048, India
| | - Karthikeyan Ramalingam
- School of Life Sciences, B.S. Abdur Rahman Crescent Institute of Science and Technology, GST Road, Vandalur, Chennai, Tamil Nadu, 600 048, India.
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Ahmed J, Navabshan I, Unnikrishnan S, Radhakrishnan L, Vasagam KPK, Ramalingam K. In Silico and In Vitro Investigation of Phytochemicals Against Shrimp AHPND Syndrome Causing PirA/B Toxins of Vibrio parahaemolyticus. Appl Biochem Biotechnol 2023; 195:7176-7196. [PMID: 36988845 DOI: 10.1007/s12010-023-04458-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/15/2023] [Indexed: 03/30/2023]
Abstract
In Southeast Asia, the penaeid shrimp aquaculture production faces a new pandemic bacterial disease called acute hepatopancreatic necrosis disease (AHPND). The highly profitable pacific white shrimp, Litopenaeus vannamei, has become a challenging species due to severe lethal infections. Recent research has identified a critical pathogen, Vibrio parahaemolyticus, which caused significant loss in the shrimp industry. The disease pathway involves a virulence plasmid encoding binary protein toxins (PirA/B) that cause cell death. The protein toxins were inherited and conjugatively transferred to other Vibrio species through a post-segregational killing system. In this study, "in silico" (Glide, 2021) analysis identified four phytocompounds as myricetin (Myr), ( +)-taxifolin (TF), (-)-epigallocatechin gallate (EGCG), and strychnine (STN) which could be most effective against both the toxins concerning its docking score and affinity. The interactions of complexes and the critical amino acids involved in docking were analyzed using the Discovery Studio (version 2016). Molecular dynamic studies showed lower root mean square deviations (RMSD) and improved stabilization of ( +)-taxifolin (TF) and (-)-epigallocatechin-3-gallate (EGCG) against both the protein toxins. The antibacterial potential of all four selected compounds had tested against pathogenic strains of V. parahaemolyticus through minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). The best MBC results were observed at concentrations of 1 mg/mL for EGCG and 1.25 mg/mL for TF. Moreover, the complete reduction of viable cell counts in the in vitro bactericidal activity had recorded after 24 h of incubation.
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Affiliation(s)
- Jahangir Ahmed
- School of Life Sciences, B.S. Abdur Rahman Crescent Institute of Science and Technology, Chennai, Tamil Nadu, India
| | - Irfan Navabshan
- School of Pharmacy, B.S. Abdur Rahman Crescent Institute of Science and Technology, Chennai, Tamil Nadu, India
| | - Sneha Unnikrishnan
- School of Life Sciences, B.S. Abdur Rahman Crescent Institute of Science and Technology, Chennai, Tamil Nadu, India
| | - Logesh Radhakrishnan
- School of Life Sciences, B.S. Abdur Rahman Crescent Institute of Science and Technology, Chennai, Tamil Nadu, India
| | - K P Kumaraguru Vasagam
- Department of Nutrition, Genetics and Biotechnology, ICAR-Central Institute of Brackishwater Aquaculture, Chennai, Tamil Nadu, India
| | - Karthikeyan Ramalingam
- School of Life Sciences, B.S. Abdur Rahman Crescent Institute of Science and Technology, Chennai, Tamil Nadu, India.
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Nehavarshini V, Unnikrishnan S, Ramalingam K. Exploring the Potential of a Herbal Nanoemulsion as an Antimicrobial Mouthwash. Appl Biochem Biotechnol 2023; 195:5777-5791. [PMID: 36708491 DOI: 10.1007/s12010-023-04356-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/10/2023] [Indexed: 01/29/2023]
Abstract
The study aimed to formulate a nanoemulsion, combine it with aqueous extracts of herbal powders, and test its efficiency as caries-preventing mouthwash. Formulation of nanoemulsion using microfluidizer, characterization of nanoemulsion, minimum inhibitory concentration, adherence test, biofilm assay, and artificial mouth assay was carried out. The biofilms of Streptococcus mutans, Lactobacillus casei, Actinomyces viscosus, and a combination of the three cultures were developed and treated with formulations to study the inhibitory effect of the samples. In artificial mouth assay, human tooth samples were used as surfaces to grow the biofilm of S. mutans, and daily, the teeth were treated with the formulations to test their real-time efficiency. The nanoemulsion was characterized using dynamic light scattering and the size of the particles was within the 100-300 nm range. Above 50 °C, the nanoemulsion combined with plant extract lost its emulsified state within 2 h of incubation, while the nanoemulsion was stable. Nanoemulsion with plant extract inhibited the adherence of L. casei (73%) and biofilm of L. casei (66%). In artificial mouth assay, after 10 days of nanoemulsion, nanoemulsion with plant extract showed DIAGNOdent pen values 3.5 and 2 respectively whereas the negative control value was 14.4 indicating caries initiation. The nanoemulsion with plant extract showed anti-adherence and anti-biofilm activity and hence can be used as a potent anticariogenic mouthwash.
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Affiliation(s)
- V Nehavarshini
- School of Life Sciences, B.S. Abdur Rahman Crescent Institute of Science and Technology, GST Road, Vandalur, Chennai, 600 048, India
| | - Sneha Unnikrishnan
- School of Life Sciences, B.S. Abdur Rahman Crescent Institute of Science and Technology, GST Road, Vandalur, Chennai, 600 048, India
| | - Karthikeyan Ramalingam
- School of Life Sciences, B.S. Abdur Rahman Crescent Institute of Science and Technology, GST Road, Vandalur, Chennai, 600 048, India.
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Hopper AB, Connor M, Salans MA, Unnikrishnan S, Huynh-Le MP, Tibbs MD, Qian AS, Reyes A, Stasenko A, McDonald C, Moiseenko V, Hattangadi-Gluth JA. Evidence-Based Multivariate Normal Tissue Complication Probability (NTCP) Study of Domain-Specific Cognitive Decline after Partial Brain RT. Int J Radiat Oncol Biol Phys 2023; 117:S75-S76. [PMID: 37784568 DOI: 10.1016/j.ijrobp.2023.06.388] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/04/2023]
Abstract
PURPOSE/OBJECTIVE(S) Beyond the hippocampus, there are no evidence-based dose constraints for eloquent brain structures which subserve memory and attention/processing speed. We performed a multivariate normal tissue complication probability analysis of post-RT neurocognitive decline, examining dosimetric predictors of eloquent brain regions. MATERIALS/METHODS Data were analyzed from a prospective longitudinal clinical trial. Patients (n = 78) with primary brain tumors receiving fractionated RT complete a comprehensive neurocognitive evaluation and high-resolution volumetric and diffusion MRI at baseline and 6 months post-RT. Image processing using robust, validated automated segmentation parcellated individual WM tracts, cortical regions, and hippocampi. Well-validated neurocognitive tests including Delis-Kaplan Executive Function System and Wechsler Adult Intelligence Scale-IV coding (attention/processing), Boston Naming Test (language) and Hopkins Verbal Learning Test and Brief Visuospatial Memory Test (verbal/visuospatial memory) were assessed. Reliable change indices adjusted for practice effects (RCI-PE) were calculated for each patient between baseline and 6 months; a negative RCI-PE was scored as decline. Univariate logistic regression was performed with mean and max dose to structures of interest as well as clinical variables. Multivariate model building was performed using automated bootstrapped logistic regression, LASSO and random forest modeling. RESULTS On univariate analysis mean and max dose to multiple regions of the corpus callosum (CC) were correlated with attention/processing speed decline; most significantly in WAIS coding, including Dmax to the anterior CC (p = 0.011) and central CC (p = 0.010), and Dmax and Dmean to the mid anterior CC (p = 0.006 and 0.010). Mean dose to the left fornix was associated with decline in memory (p = 0.023, cutoff 12.9 Gy), as were increasing age and both concurrent and adjuvant chemotherapy. On multivariate analysis for attention, automated bootstrapped logistic regression showed the most frequently selected variable was mean dose to the mid anterior CC. Performance at nested cross-validation by AUC was 0.80 (0.75-0.84); LASSO model performance by AUC was 0.76 (0.72-0.81) with Dmean to the mid anterior CC being the most frequent variable. The top five most important variables in the Random Forest as ranked by mean decrease in Gini coefficient were mean dose to mid anterior CC, all white matter, combined CC and max dose to CC and posterior CC. Model performance by AUC was 0.66 (0.60-0.71). CONCLUSION Here, we present the first, to our knowledge, NTCP model for decline in attention/processing speed, along with dosimetric predictors of memory decline beyond the hippocampus. We found that after partial brain RT, dose to several ROIs significantly correlated with post-RT impairment. These data can guide future cognitive-sparing strategies for brain RT.
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Affiliation(s)
- A B Hopper
- Department of Radiation Medicine and Applied Sciences, University of California San Diego, La Jolla, CA
| | - M Connor
- Department of Radiation Medicine and Applied Sciences, University of California San Diego, La Jolla, CA
| | - M A Salans
- University of California San Francisco, San Francisco, CA
| | - S Unnikrishnan
- Department of Radiation Medicine and Applied Sciences, University of California San Diego, La Jolla, CA
| | - M P Huynh-Le
- Radiation Oncology, The Brooklyn Cancer Center, Brooklyn, NY
| | - M D Tibbs
- Department of Radiation Medicine and Applied Sciences, University of California San Diego, La Jolla, CA
| | - A S Qian
- Department of Radiation Medicine and Applied Sciences, University of California San Diego, La Jolla, CA
| | - A Reyes
- Department of Radiation Medicine and Applied Sciences, University of California San Diego, La Jolla, CA
| | - A Stasenko
- Department of Psychiatry, University of California San Diego, La Jolla, CA
| | - C McDonald
- Department of Radiation Medicine and Applied Sciences, University of California San Diego, La Jolla, CA; Department of Psychiatry, University of California San Diego, La Jolla, CA
| | - V Moiseenko
- Department of Radiation Medicine and Applied Sciences, University of California San Diego, La Jolla, CA
| | - J A Hattangadi-Gluth
- Department of Radiation Medicine and Applied Sciences, University of California San Diego, La Jolla, CA
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Gudipati S, Salans M, Karunamuni R, Unnikrishnan S, Yu J, Tibbs M, Huynh-Le M, Qian A, Hermann G, Connor M, Reyes A, Stasenko A, McDonald C, Hattangadi-Gluth J. Role of Thalamus and Thalamic Nuclei in Mediating Post-Treatment Cognitive Changes in Primary Brain Tumor Patients. Int J Radiat Oncol Biol Phys 2022. [DOI: 10.1016/j.ijrobp.2022.07.445] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Unnikrishnan S, Karunamuni R, Salans M, Gudipati S, Qian A, Yu J, Connor M, Huynh-Le M, Tibbs M, Hermann G, Reyes A, Stasenko A, Seibert T, McDonald C, Hattangadi-Gluth J. Prospective Longitudinal Analysis of Amygdala Volumes and Association with Mood and Memory Outcomes in Brain Tumor Patients. Int J Radiat Oncol Biol Phys 2022. [DOI: 10.1016/j.ijrobp.2022.07.820] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
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Qian A, Karunamuni R, Unnikrishnan S, Salans M, Gudipati S, Yu J, Connor M, Hermann G, Huynh-Le M, Tibbs M, Reyes A, Stasenko A, McDonald C, Hattangadi-Gluth J. Beyond the Hippocampus: White Matter Memory Network Implicated in Post-Radiation Memory Decline in Primary Brain Tumor Patients. Int J Radiat Oncol Biol Phys 2022. [DOI: 10.1016/j.ijrobp.2022.07.447] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Ravi GN, Navabshan I, Unnikrishnan S, Ramalingam K. In Silico Protein-Protein Interaction of Pterois volitans Venom with Cancer Inducers of Helicobacter pylori. Appl Biochem Biotechnol 2021; 194:354-367. [PMID: 34843077 DOI: 10.1007/s12010-021-03763-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2021] [Accepted: 11/08/2021] [Indexed: 10/19/2022]
Abstract
Gastric cancer is a pathological condition induced by the bacteria Helicobacter pylori. Targeting the key virulence factors of H. pylori causing gastric cancer is a promising method for treating gastric cancer. Recently, research has been focused on analyzing the adrenergic, cholinergic, and anti-cancer properties of their venom proteins. Testing the anti-cancer activity of the lethal proteins in the venom of P. volitans provides a bioactive compound for cancer treatment. Still, it is also helpful to eliminate the ecological imbalance caused by these fish in the marine environment. This study focuses on an in silico approach using Z-dock to analyze the bioactive prospective of the venom proteins of P. volitans against the essential virulence proteins of H. pylori responsible for inducing cancer. Our in silico docking study using a computational model of the venom proteins and H. pylori proteins has displayed the possible interactions between these proteins. The results revealed that P. volitans hyaluronidase and PV toxin's venom proteins effectively interact with H. pylori proteins Cag A, Cag L, GGT, Cag D, and urease that may be promising proteins in cancer therapy.
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Affiliation(s)
- Guru Nivetha Ravi
- School of Life Sciences, B.S. Abdur Rahman Crescent Institute of Science and Technology, GST Road, Vandalur, Chennai, 600 048, India
| | - Irfan Navabshan
- School of Pharmacy, B.S. Abdur Rahman Crescent Institute of Science and Technology, GST Road, Vandalur, 600 048, Chennai, India
| | - Sneha Unnikrishnan
- School of Life Sciences, B.S. Abdur Rahman Crescent Institute of Science and Technology, GST Road, Vandalur, Chennai, 600 048, India
| | - Karthikeyan Ramalingam
- School of Life Sciences, B.S. Abdur Rahman Crescent Institute of Science and Technology, GST Road, Vandalur, Chennai, 600 048, India.
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Qian A, Qiao E, Unnikrishnan S, Connor M, Kotha N, Voora R, Yu J, Jona H, Murphy J. Effect of Frailty on Unplanned 30-Day Readmissions and Mortality in Cancer Patients. Int J Radiat Oncol Biol Phys 2021. [DOI: 10.1016/j.ijrobp.2021.07.265] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Yu J, Salans M, Karunamuni R, Tibbs M, Huynh-Le M, Unnikrishnan S, Connor M, Qian A, Reyes A, Stasenko A, Seibert T, McDonald C, Hattangadi-Gluth J. Entorhinal Cortical Volume is Associated With Verbal and Visuospatial Memory Performance in Primary Brain Tumor Patients. Int J Radiat Oncol Biol Phys 2021. [DOI: 10.1016/j.ijrobp.2021.07.231] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Unnikrishnan S, Karunamuni R, Kim G, Connor M, Salans M, Sanghvi P, Bruggeman A, Simpson D, Yu J, Reyes A, Stasenko A, Moore K, Moiseenko V, McDonald C, Hattangadi-Gluth J. Phase II Clinical Trial of Image-Guided Cognitive-Sparing SRS in Patients With Brain Metastases. Int J Radiat Oncol Biol Phys 2021. [DOI: 10.1016/j.ijrobp.2021.07.1564] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Ameenudeen S, Unnikrishnan S, Ramalingam K. Statistical optimization for the efficacious degradation of reactive azo dyes using Acinetobacter baumannii JC359. J Environ Manage 2021; 279:111512. [PMID: 33162232 DOI: 10.1016/j.jenvman.2020.111512] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Revised: 08/14/2020] [Accepted: 10/10/2020] [Indexed: 06/11/2023]
Abstract
The aim of this study is to biodegrade the reactive azo dyes- Reactive black 5 (B-GDN), Reactive red 120 (RP) and Reactive blue 19 (RNB) using bacteria Acinetobacter baumannii JC359. Optimization of the process variables such as pH, temperature, dye concentration, incubation time, inoculum volume and dynamic incubating conditions for dye decolorization were performed using One Factor At a Time (OFAT) approach. Box- Behnken Design (BBD) of Response Surface Methodology (RSM) was further used to optimize the process variables. Decolorization rates of 98.8% for B-GDN, 96% for RP and 96.2% for RNB were observed after treating with A. baumannii for 48 h using the obtained design value. UV-Visible spectrophotometry and FT-IR spectral scan of dye and degraded metabolites confirmed that biodegradation had taken place. Further, the phytotoxicity evaluation was performed with Vigna radiata seeds and the degraded metabolites proved to be non-toxic. Docking studies were performed and it was found that there was significant binding affinity between the dyes and azoreductase enzyme of A. baumannii. Thus, the biodegradation of these reactive azo dyes was found to be a suitable alternative for the effective treatment of textile dyes.
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Affiliation(s)
- Shabnam Ameenudeen
- School of Life Sciences, B. S. Abdur Rahman Crescent Institute of Science and Technology, Chennai, 600 048, India.
| | - Sneha Unnikrishnan
- School of Life Sciences, B. S. Abdur Rahman Crescent Institute of Science and Technology, Chennai, 600 048, India.
| | - Karthikeyan Ramalingam
- School of Life Sciences, B. S. Abdur Rahman Crescent Institute of Science and Technology, Chennai, 600 048, India.
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Unnikrishnan S, Brenin DR, Suralik G, Showalter TN, Shami V, Libby B, Watkins WT, Showalter SL, Zhao F, Govinahallisathyanarayana S, Hossack JA. Use of an ultrasound imaging device within the applicator to evaluate placement and support treatment planning for breast brachytherapy and intraoperative radiation therapy. Brachytherapy 2020; 20:200-206. [PMID: 33041231 DOI: 10.1016/j.brachy.2020.08.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 08/13/2020] [Accepted: 08/14/2020] [Indexed: 10/23/2022]
Abstract
PURPOSE We evaluated the use of ultrasound imaging within a brachytherapy applicator as a method for applicator positioning, evaluation, and treatment planning in a series of in vitro, cadaver, and human studies. METHODS AND MATERIALS We evaluated the performance of a prototype system comprising a small ultrasound imaging catheter inserted within the lumen of a balloon brachytherapy catheter. We tested the device in an ultrasound phantom, in human breast tissue, and in an endoscopic ultrasound catheter in cadaveric breast tissue. We evaluated the visualization of adjacent tissue to consider future development of a similar system for use in brachytherapy and intraoperative radiation therapy. RESULTS Based on the ultrasound images obtained in an ultrasound phantom, cadaveric breast, and human participants, we observed that an ultrasound imaging catheter placed within the lumen of a brachytherapy applicator can effectively image adjacent tissue, ribs, and air voids, with appropriate quality to support clinical use. We observed high correlation in clinically useful information detected on ultrasound and comparative CT, with ultrasound spatial resolution near 1 mm (spatially variant). CONCLUSIONS The findings from our pilot work suggest that real-time ultrasound imaging, operated from within the applicator, is a promising technique for image guidance and treatment planning during brachytherapy and intraoperative radiation therapy. Further expansion of this technology for clinical use will require development of a cohesive system of components to suit specific clinical applications.
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Affiliation(s)
- S Unnikrishnan
- Department of Biomedical Engineering, School of Engineering, University of Virginia, Charlottesville, VA
| | - D R Brenin
- Department of Surgery, University of Virginia School of Medicine, Charlottesville, VA
| | - G Suralik
- Department of Radiation Oncology, University of Virginia School of Medicine, Charlottesville, VA
| | - T N Showalter
- Department of Radiation Oncology, University of Virginia School of Medicine, Charlottesville, VA
| | - V Shami
- Department of Medicine, University of Virginia School of Medicine, Charlottesville, VA
| | - B Libby
- Department of Radiation Oncology, University of Virginia School of Medicine, Charlottesville, VA
| | - W T Watkins
- Department of Radiation Oncology, University of Virginia School of Medicine, Charlottesville, VA
| | - S L Showalter
- Department of Surgery, University of Virginia School of Medicine, Charlottesville, VA
| | - F Zhao
- Department of Biomedical Engineering, School of Engineering, University of Virginia, Charlottesville, VA
| | | | - J A Hossack
- Department of Biomedical Engineering, School of Engineering, University of Virginia, Charlottesville, VA.
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Khan MH, Unnikrishnan S, Ramalingam K. Bactericidal potential of silver-tolerant bacteria derived silver nanoparticles against multi drug resistant ESKAPE pathogens. Biocatalysis and Agricultural Biotechnology 2019. [DOI: 10.1016/j.bcab.2018.12.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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Ragaseema VM, Unnikrishnan S, Kalliyana Krishnan V, Krishnan LK. The antithrombotic and antimicrobial properties of PEG-protected silver nanoparticle coated surfaces. Biomaterials 2012; 33:3083-92. [PMID: 22284585 DOI: 10.1016/j.biomaterials.2012.01.005] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2011] [Accepted: 01/04/2012] [Indexed: 11/17/2022]
Abstract
Cardiovascular implant-associated complications such as infection and thrombosis may be reduced by modification of device surfaces using antimicrobial and antithrombotic agents. Silver nanoparticles (SNPs) are well accepted for its broad-spectrum antimicrobial effect. A recent report suggested its antiplatelet effect also. So the hypothesis of this study is that polyethylene glycol (PEG) protected SNPs can be incorporated with biomaterials to attain dual properties; and by adjusting an optimum concentration, its cytotoxicity to tissues and cells can be prevented. To prove this, detailed study of PEG-SNP was done at three levels: (i) direct inhibitory effect on platelet activation, aggregation and biochemical pathways when PEG-SNP is added into platelet suspension; (ii) inhibition of platelet adhesion to PEG-SNP incorporated biological matrix and polymer scaffold and (iii) non-cytotoxic behavior of immobilized PEG-SNP in fibrin matrix. Inhibitory effects demonstrated are on: platelet function by aggregometry, exposure of activation and apoptosis markers by flow cytometry, biochemical pathway by malondealdehyde (MDA) estimation and protein phosphorylation by Western blot. Reduced platelet adhesion onto PEG-SNP incorporated scaffold is shown using scanning electron microscopy (SEM). Non-toxic behavior of endothelial cells (EC) and smooth muscle cells (SMC) grown on PEG-SNP-fibrin disc is shown by fluorescence microscopy and cell phenotype stability by real-time polymerase chain reaction (PCR).
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Affiliation(s)
- V M Ragaseema
- Thrombosis Research Unit, Biomedical Technology Wing, Sree Chitra Tirunal Institute for Medical Sciences & Technology, Trivandrum-695012, India
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Unnikrishnan S, Jansen HV, Falke FH, Tas NR, Van Wolferen HAGM, De Boer MJ, Sanders RGP, Elwenspoek MC. Transition flow through an ultra-thin nanosieve. Nanotechnology 2009; 20:305304. [PMID: 19581693 DOI: 10.1088/0957-4484/20/30/305304] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The fabrication and gas flow characterization of an ultra-thin inorganic nanosieve structured by interference lithography and a bond-micromachining approach are reported. The nanosieve has been observed to exhibit transition gas flow behaviour around atmospheric pressure and ambient temperature. The small lip thickness (45 nm) of the nanopores with respect to their diameter (120 nm) helps in understanding pure transition flow by minimizing interactions between the molecule and inner pore wall. Due to the absence of these collisions, the transition flux is the superimposition of viscous and molecular fluxes without the need for higher-order slip correction. The nanosieve shows a flow selectivity of 3.1 between helium and argon at 20 mbar.
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Affiliation(s)
- S Unnikrishnan
- Transducers Science and Technology Group, MESA+ Institute for Nanotechnology, University of Twente, PO Box 217, 7500 AE Enschede, The Netherlands.
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Vyas R, Jani K, Unnikrishnan S, Bhavsar D, Kumar A. High Dose Rate Brachytherapy Boost with Newly Made Surface Applicator in Anal Canal Cancers: Our Experience. Int J Radiat Oncol Biol Phys 2008. [DOI: 10.1016/j.ijrobp.2008.06.1717] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Sarathy J, Mayer RA, Jung K, Unnikrishnan S, Kwong DL, Campbell JC. Normal-incidence grating couplers in Ge-Si. Opt Lett 1994; 19:798-800. [PMID: 19844449 DOI: 10.1364/ol.19.000798] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
We report a normal-incidence grating coupler that is monolithically integrated with a Ge(x)Si(1-x) rib waveguide. The design, fabrication, and testing procedures are described for a 0.33-microm-period grating coupler integrated with a Ge(0.04)Si(0.96) waveguide. Also, a theoretical analysis based on coupler-mode theory has been carried out to predict the coupling efficiency and its dependence on the angle of incidence of light. For normal incidence the measured efficiency of 6.5% was found to be in good agreement with the theoretical prediction of 6.9%. The measured FWHM of the acceptance angle about the normal was 5 degrees , compared with the theoretical prediction of 3 degrees .
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Unnikrishnan S, Chakrabarty DK. Magnetic properties and domain state of the magnesium ferrite–magnesium titanate solid solutions. ACTA ACUST UNITED AC 1990. [DOI: 10.1002/pssa.2211210132] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Cowsik R, Krishnan N, Tandon SN, Unnikrishnan S. Strength of intermediate-range forces coupling to isospin. Phys Rev Lett 1990; 64:336-339. [PMID: 10041954 DOI: 10.1103/physrevlett.64.336] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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