54 results on '"Balasubramanian SK"'
Search Results
2. Clinical and molecular characteristics of extramedullary acute myeloid leukemias.
- Author
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Kewan T, Bahaj WS, Gurnari C, Ogbue OD, Mukherjee S, Advani A, Cook JR, Rogers HJ, Carraway HE, Balasubramanian SK, Visconte V, and Maciejewski JP
- Subjects
- Humans, Middle Aged, Male, Female, Aged, Adult, Young Adult, Prognosis, Aged, 80 and over, Adolescent, Mutation, Leukemia, Myeloid, Acute pathology, Leukemia, Myeloid, Acute genetics
- Published
- 2024
- Full Text
- View/download PDF
3. Paroxysmal nocturnal hemoglobinuria-related thrombosis in the era of novel therapies: a 2043-patient-year analysis.
- Author
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Gurnari C, Awada H, Pagliuca S, Dima D, Ullah F, Kawashima N, Kubota Y, Colak C, Visconte V, Patel BJ, Dhillon V, Marneni N, Balasubramanian SK, Kishtagari A, Bat T, and Maciejewski JP
- Subjects
- Humans, Male, Female, Middle Aged, Adult, Aged, Follow-Up Studies, Hemoglobinuria, Paroxysmal complications, Hemoglobinuria, Paroxysmal drug therapy, Thrombosis etiology, Thrombosis drug therapy, Anticoagulants therapeutic use
- Abstract
Abstract: Thrombophilia is one of the principal features of paroxysmal nocturnal hemoglobinuria (PNH) and constitutes the main cause of disease morbidity/mortality. Anticomplement treatment has revolutionized the natural history of PNH, with control of the hemolytic process and abolition of thrombotic events (TEs). However, no guidelines exist for the management of thromboembolic complications in this setting, with type and duration of anticoagulation depending on individual practices. Besides, a scarcity of data is present on the efficacy of direct oral anticoagulants (DOACs). Herein, we accrued a large real-world cohort of patients with PNH from 4 US centers to explore features, predictors of TE, and anticoagulation strategies. Among 267 patients followed up for a total of 2043 patient-years, 56 (21%) developed TEs. These occurred at disease onset in 43% of cases, involving more frequently the venous system, typically as Budd-Chiari syndrome. Rate of TEs was halved in patients receiving complement inhibitors (21 vs 40 TEs per 1000 patient-years in untreated cases, with a 2-year cumulative incidence of thrombosis of 3.9% vs 18.3%, respectively), and varied according to PNH granulocytes and erythrocytes clone size, type, disease activity parameters, as well as number (≥2 mutations, or less) and variant allelic frequency of PIGA mutations. Anticoagulation with warfarin (39%), DOACs (37%), and low-molecular weight heparin (16%) was administered for a median of 29 months (interquartile range [IQR], 9-61.8). No thrombotic recurrence was observed in 19 patients treated with DOACs at a median observation of 17.1 months (IQR, 8.9-45) whereas 14 cases discontinued anticoagulation without TE recurrence at a median time of 51.4 months (IQR, 29.9-86.8)., (© 2024 American Society of Hematology. Published by Elsevier Inc. All rights are reserved, including those for text and data mining, AI training, and similar technologies.)
- Published
- 2024
- Full Text
- View/download PDF
4. Oral health: A siloed yet modifiable cognitive impairment risk factor.
- Author
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Balasubramanian SK and Vinayachandran D
- Subjects
- Humans, Risk Factors, Oral Health, Cognitive Dysfunction
- Published
- 2024
- Full Text
- View/download PDF
5. Author Correction: Molecular patterns identify distinct subclasses of myeloid neoplasia.
- Author
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Kewan T, Durmaz A, Bahaj W, Gurnari C, Terkawi L, Awada H, Ogbue OD, Ahmed R, Pagliuca S, Awada H, Kubota Y, Mori M, Ponvilawan B, Al-Share B, Patel BJ, Carraway HE, Scott J, Balasubramanian SK, Bat T, Madanat Y, Sekeres MA, Haferlach T, Visconte V, and Maciejewski JP
- Published
- 2024
- Full Text
- View/download PDF
6. Paternal alcohol exposure and dental-facial anomalies in offspring.
- Author
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Vinayachandran D and Balasubramanian SK
- Published
- 2023
- Full Text
- View/download PDF
7. Novel scheme for defining the clinical implications of TP53 mutations in myeloid neoplasia.
- Author
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Bahaj W, Kewan T, Gurnari C, Durmaz A, Ponvilawan B, Pandit I, Kubota Y, Ogbue OD, Zawit M, Madanat Y, Bat T, Balasubramanian SK, Awada H, Ahmed R, Mori M, Meggendorfer M, Haferlach T, Visconte V, and Maciejewski JP
- Subjects
- Humans, Mutation, Prognosis, Tumor Suppressor Protein p53 genetics, Leukemia, Myeloid, Acute genetics
- Abstract
Background: TP53 mutations (TP53
MT ) occur in diverse genomic configurations. Particularly, biallelic inactivation is associated with poor overall survival in cancer. Lesions affecting only one allele might not be directly leukemogenic, questioning the presence of cryptic biallelic subclones in cases with dismal prognosis., Methods: We have collected clinical and molecular data of 7400 patients with myeloid neoplasms and applied a novel model by identifying an optimal VAF cutoff using a statistically robust strategy of sampling-based regression on survival data to accurately classify the TP53 allelic configuration and assess prognosis more precisely., Results: Overall, TP53MT were found in 1010 patients. Following the traditional criteria, 36% of the cases were classified as single hits, while 64% exhibited double hits genomic configuration. Using a newly developed molecular algorithm, we found that 579 (57%) patients had unequivocally biallelic, 239 (24%) likely contained biallelic, and 192 (19%) had most likely monoallelic TP53MT . Interestingly, our method was able to upstage 192 out of 352 (54.5%) traditionally single hit lesions into a probable biallelic category. Such classification was further substantiated by a survival-based model built after re-categorization. Among cases traditionally considered monoallelic, the overall survival of those with probable monoallelic mutations was similar to the one of wild-type patients and was better than that of patients with a biallelic configuration. As a result, patients with certain biallelic hits, regardless of the disease subtype (AML or MDS), had a similar prognosis. Similar results were observed when the model was applied to an external cohort. In addition, single-cell DNA studies unveiled the biallelic nature of previously considered monoallelic cases., Conclusion: Our novel approach more accurately resolves TP53 genomic configuration and uncovers genetic mosaicism for the use in the clinical setting to improve prognostic evaluation., (© 2023. BioMed Central Ltd., part of Springer Nature.)- Published
- 2023
- Full Text
- View/download PDF
8. Molecular patterns identify distinct subclasses of myeloid neoplasia.
- Author
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Kewan T, Durmaz A, Bahaj W, Gurnari C, Terkawi L, Awada H, Ogbue OD, Ahmed R, Pagliuca S, Awada H, Kubota Y, Mori M, Ponvilawan B, Al-Share B, Patel BJ, Carraway HE, Scott J, Balasubramanian SK, Bat T, Madanat Y, Sekeres MA, Haferlach T, Visconte V, and Maciejewski JP
- Subjects
- Humans, Mutation, Myelodysplastic Syndromes diagnosis, Myelodysplastic Syndromes genetics, Myelodysplastic Syndromes pathology, Myeloproliferative Disorders, Leukemia, Myeloid, Acute diagnosis, Leukemia, Myeloid, Acute genetics, Leukemia, Myeloid, Acute pathology
- Abstract
Genomic mutations drive the pathogenesis of myelodysplastic syndromes and acute myeloid leukemia. While morphological and clinical features have dominated the classical criteria for diagnosis and classification, incorporation of molecular data can illuminate functional pathobiology. Here we show that unsupervised machine learning can identify functional objective molecular clusters, irrespective of anamnestic clinico-morphological features, despite the complexity of the molecular alterations in myeloid neoplasia. Our approach reflects disease evolution, informed classification, prognostication, and molecular interactions. We apply machine learning methods on 3588 patients with myelodysplastic syndromes and secondary acute myeloid leukemia to identify 14 molecularly distinct clusters. Remarkably, our model shows clinical implications in terms of overall survival and response to treatment even after adjusting to the molecular international prognostic scoring system (IPSS-M). In addition, the model is validated on an external cohort of 412 patients. Our subclassification model is available via a web-based open-access resource ( https://drmz.shinyapps.io/mds_latent )., (© 2023. The Author(s).)
- Published
- 2023
- Full Text
- View/download PDF
9. Novel Scheme for Defining the Clinical Implications of TP53 Mutations in Myeloid Neoplasia.
- Author
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Bahaj W, Kewan T, Gurnari C, Durmaz A, Ponvilawan B, Pandit I, Kubota Y, Ogbue OD, Zawit M, Madanat Y, Bat T, Balasubramanian SK, Awada H, Ahmed R, Mori M, Meggendorfer M, Haferlach T, Visconte V, and Maciejewski JP
- Abstract
Background: TP53 mutations ( TP53
MT ) occur in diverse genomic configurations. Particularly, biallelic inactivation is associated with poor overall survival in cancer. Lesions affecting only one allele might not be directly leukemogenic, questioning the presence of cryptic biallelic subclones in cases with dismal prognosis. Methods: We have collected clinical and molecular data of 7400 patients with myeloid neoplasms and applied a novel model to properly resolve the allelic configuration of TP53MT and assess prognosis more precisely. Results: Overall, TP53MT were found in 1010 patients. Following the traditional criteria, 36% of cases were classified as single hits while 64% exhibited double hits genomic configuration. Using a newly developed molecular algorithm, we found that 579 (57%) patients had unequivocally biallelic, 239 (24%) likely contained biallelic, and 192 (19%) had most likely monoallelic TP53MT . Such classification was further substantiated by a survival-based model built after re-categorization. Among cases traditionally considered monoallelic, the overall survival of those with probable monoallelic mutations was similar to the one of wild-type patients and was better than that of patients with a biallelic configuration. As a result, patients with certain biallelic hits, regardless of the disease subtype (AML or MDS), had a similar prognosis. Similar results were observed when the model was applied to an external cohort. These results were recapitulated by single-cell DNA studies, which unveiled the biallelic nature of previously considered monoallelic cases. Conclusion: Our novel approach more accurately resolves TP53 genomic configuration and uncovers genetic mosaicism for the use in the clinical setting to improve prognostic evaluation.- Published
- 2023
- Full Text
- View/download PDF
10. Oral lesions in monkeypox- A definite consideration!
- Author
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Balasubramanian SK and Vinayachandran D
- Subjects
- Humans, Mpox (monkeypox) pathology, Oral Ulcer
- Abstract
Competing Interests: Declaration of Competing Interest None
- Published
- 2022
- Full Text
- View/download PDF
11. Late Presentation of Dyskeratosis Congenita: Germline Predisposition to Adult-Onset Secondary Acute Myeloid Leukemia.
- Author
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Ramos H, Aly MM, and Balasubramanian SK
- Abstract
Classic dyskeratosis congenita is a hereditary disease where the majority of patients present with bone marrow failure and mucocutaneous changes: mainly skin pigmentation, nail dystrophy, oral premalignant leukoplakia, in addition to increased risk for malignancies. A 63-year-old man with a long history of untreated chronic pulmonary disease, a smoker in the past, presented initially with pancytopenia and a clinical diagnosis of myelodysplastic syndrome with excess blasts returned a month later with leukocytosis (WBC 215.9 × 10
6 /μL) and diagnosed with acute myeloid leukemia (AML) with deletion of chromosome 7 and FLT3 -TKD mutation. The patient's mother and sister died in their 6th decade from rapidly progressing fulminant pulmonary fibrosis. He had abnormal skin pigmentation and oral leukoplakia on presentation. He was induced with 7 + 3 chemotherapy and started on midostaurin but experienced prolonged cytopenias, complicated by hypoxic acute on chronic respiratory failure requiring intubation and mechanical ventilation. D + 28 and D + 36 bone marrow examination showed trilineage hypoplasia but no blasts, though the D + 28 bone marrow biopsy revealed one metaphase with del (7) that was cleared on D + 35. The constellation of clinical features and strong family history along with del 7 and FLT3 -TKD AML with preceding MDS highly suggests a germline predisposition state dyskeratosis congenita. Germline predispositions are often underrecognized as delayed onset conditions leading to AML and may have treatment and preventative implications especially genetic counseling for blood-related family members.- Published
- 2022
- Full Text
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12. Prenatal areca nut consumption: overlooked aspects of a widely embraced habit.
- Author
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Balasubramanian SK and Divya V
- Subjects
- Female, Habits, Humans, Pregnancy, Areca, Nuts
- Published
- 2022
- Full Text
- View/download PDF
13. Selective inhibition of nuclear export: a promising approach in the shifting treatment paradigms for hematological neoplasms.
- Author
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Balasubramanian SK, Azmi AS, and Maciejewski J
- Subjects
- Animals, Antineoplastic Agents therapeutic use, Drug Discovery, Hematologic Neoplasms metabolism, Humans, Karyopherins metabolism, Leukemia, Myeloid, Acute drug therapy, Leukemia, Myeloid, Acute metabolism, Molecular Targeted Therapy, Receptors, Cytoplasmic and Nuclear metabolism, Exportin 1 Protein, Active Transport, Cell Nucleus drug effects, Antineoplastic Agents pharmacology, Hematologic Neoplasms drug therapy
- Abstract
Novel targeted therapeutics alone or in rational combinations are likely to dominate the future management of various hematological neoplasms. However, the challenges currently faced are the molecular heterogeneity in driver lesions and genetic plasticity leading to multiple resistance pathways. Thus, progress has overall been gradual. For example, despite the advent of targeted agents against actionable drivers like FLT3 in acute myeloid leukemia (AML), the prognosis remains suboptimal in newly diagnosed and dismal in the relapsed/refractory (R/R) setting, due to other molecular abnormalities contributing to inherent and acquired treatment resistance. Nuclear export inhibitors are of keen interest because they can inhibit several active tumorigenic processes simultaneously and also synergize with other targeted drugs and chemotherapy. XPO1 (or CRM1, chromosome maintenance region 1) is one of the most studied exportins involved in transporting critical cargoes, including tumor suppressor proteins like p27, p53, and RB1. Apart from the TSP cargo transport and its role in drug resistance, XPO1 inhibition results in retention of master transcription factors essential for cell differentiation, cell survival, and autophagy, rendering cells more susceptible to the effects of other antineoplastic agents, including targeted therapies. This review will dissect the role of XPO1 inhibition in hematological neoplasms, focusing on mechanistic insights gleaned mainly from work with SINE compounds. Future potential combinatorial strategies will be discussed., (© 2021. The Author(s).)
- Published
- 2022
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14. PAK4 and NAMPT as Novel Therapeutic Targets in Diffuse Large B-Cell Lymphoma, Follicular Lymphoma, and Mantle Cell Lymphoma.
- Author
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Khan HY, Uddin MH, Balasubramanian SK, Sulaiman N, Iqbal M, Chaker M, Aboukameel A, Li Y, Senapedis W, Baloglu E, Mohammad RM, Zonder J, and Azmi AS
- Abstract
Diffuse large B-cell lymphoma (DLBCL), grade 3b follicular lymphoma (FL), and mantle cell lymphoma (MCL) are aggressive non-Hodgkin's lymphomas (NHL). Cure rates are suboptimal and novel treatment strategies are needed to improve outcomes. Here, we show that p21-activated kinase 4 (PAK4) and nicotinamide phosphoribosyl transferase (NAMPT) is critical for lymphoma subsistence. Dual targeting of PAK4-NAMPT by the Phase I small molecule KPT-9274 suppressed cell proliferation in DLBCL, FL, and MCL. Growth inhibition was concurrent with apoptosis induction alongside activation of pro-apoptotic proteins and reduced pro-survival markers. We observed NAD suppression, ATP reduction, and consequent cellular metabolic collapse in lymphoma cells due to KPT-9274 treatment. KPT-9274 in combination with standard-of-care chemotherapeutics led to superior inhibition of cell proliferation. In vivo, KPT-9274 could markedly suppress the growth of WSU-DLCL2 (DLBCL), Z-138, and JeKo-1 (MCL) sub-cutaneous xenografts, and a remarkable increase in host life span was shown, with a 50% cure of a systemic WSU-FSCCL (FL) model. Residual tumor analysis confirmed a reduction in total and phosphorylated PAK4 and activation of the pro-apoptotic cascade. This study, using various preclinical experimental models, demonstrates the therapeutic potential of targeting PAK4-NAMPT in DLBCL, FL, and MCL. The orally bioavailable, safe, and efficacious PAK4-NAMPT dual inhibitor KPT-9274 warrants further clinical investigation.
- Published
- 2021
- Full Text
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15. Circular RNAs in acute myeloid leukemia.
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Singh V, Uddin MH, Zonder JA, Azmi AS, and Balasubramanian SK
- Subjects
- Animals, Disease Management, Disease Susceptibility, Drug Resistance, Neoplasm genetics, Humans, Leukemia, Myeloid, Acute diagnosis, Leukemia, Myeloid, Acute metabolism, Leukemia, Myeloid, Acute therapy, Molecular Diagnostic Techniques, Neoplasm Grading, Neoplasm Staging, Prognosis, RNA Interference, RNA, Messenger genetics, RNA, Untranslated, Signal Transduction, Biomarkers, Tumor, Gene Expression Regulation, Leukemic, Leukemia, Myeloid, Acute genetics, RNA, Circular
- Abstract
Although mechanistic studies clarifying the molecular underpinnings of AML have facilitated the development of several novel targeted therapeutics, most AML patients still relapse. Thus, overcoming the inherent and acquired resistance to current therapies remains an unsolved clinical problem. While current diagnostic modalities are primarily defined by gross morphology, cytogenetics, and to an extent, by deep targeted gene sequencing, there is an ongoing demand to identify newer diagnostic, therapeutic and prognostic biomarkers for AML. Recent interest in exploring the role of circular RNA (circRNA) in elucidating AML biology and therapy resistance has been promising. This review discerns the circular RNAs' evolving role on the same scientific premise and attempts to identify its potential in managing AML., (© 2021. The Author(s).)
- Published
- 2021
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16. Is Paget Disease of Bone a Predominant Disease of South India? Clinical Characteristics, Therapeutic Outcome and Follow Up of 66 Patients from Tamil Nadu and Brief Review of Epidemiology.
- Author
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Asirvatham AR, Kannan S, Mahadevan S, Balachandran K, Sampathkumar G, Sadacharan D, and Balasubramanian SK
- Abstract
Competing Interests: There are no conflicts of interest.
- Published
- 2020
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17. Is Paget Disease of Bone more Common in South India? Clinical Characteristics, Therapeutic Outcome and follow-up of 66 Patients from Tamil Nadu.
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Asirvatham AR, Kannan S, Mahadevan S, Balachandran K, Sampathkumar G, Sadacharan D, and Balasubramanian SK
- Abstract
Introduction: Paget disease of bone (PDB) is a disorder of altered bone remodeling mainly characterized by increased osteoclastic activity. While the exact Indian prevalence remains unknown, a clustering of published cases suggests South Indian predominance., Objective: To study the clinico-biochemical profile and therapeutic response of patients with PDB and briefly review the epidemiology of PDB from an Indian perspective., Materials and Methods: Retrospective data was collected from the charts of patients who have been seen in endocrine out-patient clinics in Tamil Nadu over a 12-year period. Published literature on PDB from India was reviewed., Results: A total of 66 patients (71% males) predominantly from Tamil Nadu were studied. The mean age at presentation was 67 ± 8 years. Polyostotic involvement was seen in 89% and familial occurrence of PDB in 5 patients. Symptoms at presentation mainly included bone pain (51%) and skeletal deformities (18%). Scalp vein sign (21%) and sensorineural hearing loss (64%) were also noted. Incidental PDB detection by raised serum alkaline phosphatase (SAP) levels was observed in 17% and by abnormal fluorodeoxyglucose-positron emission tomography (FDG-PET) scan in 6% of cases. Mean SAP at presentation was 606 ± 438 IU/L (Normal, 76-140). Major skeletal site involvement includes pelvis (62.1%) and spine (34.8%). Mean (range) follow-up of the cohort was 3.4 yrs (1-12 yrs). In all, 64 subjects received zoledronate and two received alendronate, and mean (SD) SAP at 1-year was 73 ± 42 IU/L. All but two showed remission at the end of 1 year. Two had pathological fractures and two had sarcomas. A review of epidemiology of PDB in Indian literature clearly showed a South Indian predilection for unclear reasons., Conclusion: In our cohort of PDB, male gender, polyostotic involvement, and hearing impairment were noted in more than two-thirds of patients and single-dose intravenous zoledronate was effective in normalizing SAP in almost all patients. PDB is intriguingly more common in South India and this needs more exploration., Competing Interests: There are no conflicts of interest., (Copyright: © 2020 Indian Journal of Endocrinology and Metabolism.)
- Published
- 2020
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18. Impact of EGFR mutation and ALK rearrangement on the outcomes of non-small cell lung cancer patients with brain metastasis.
- Author
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Balasubramanian SK, Sharma M, Venur VA, Schmitt P, Kotecha R, Chao ST, Suh JH, Angelov L, Mohammadi AM, Vogelbaum MA, Barnett GH, Jia X, Pennell NA, and Ahluwalia MS
- Subjects
- Adult, Aged, Aged, 80 and over, Brain Neoplasms genetics, Brain Neoplasms mortality, Carcinoma, Non-Small-Cell Lung mortality, Carcinoma, Non-Small-Cell Lung secondary, ErbB Receptors genetics, Female, Gene Rearrangement, Humans, Lung Neoplasms mortality, Lung Neoplasms pathology, Male, Middle Aged, Mutation, Prognosis, Progression-Free Survival, Anaplastic Lymphoma Kinase genetics, Brain Neoplasms secondary, Carcinoma, Non-Small-Cell Lung genetics, Lung Neoplasms genetics
- Abstract
Background: The impact of activating alterations in non-small cell lung cancer (NSCLC) (epidermal growth factor receptor [EGFR] mutation/anaplastic lymphoma kinase [ALK] translocation) in prognosticating patients with brain metastasis (BM) is not well defined. This study was sought to identify this impact in NSCLC patients with BM accounting for the known validated variables., Methods: Among 1078 NSCLC-BM patients diagnosed/treated between January 1, 2000 and December 31, 2015, three hundred and forty-eight with known EGFR/ALK status were analyzed. Overall survival (OS) and intracranial progression-free survival (PFS) were measured from the time of BM., Results: Ninety-one patients had either ALK (n = 23) alterations or EGFR (n = 68) mutation and 257 were wild type (WT; negative actionable mutations/alterations). Median age of EGFR/ALK+ NSCLC BM patients was 60 years (range 29.8-82.6 y) and ~50% (n = 44) had Karnofsky performance status (KPS) score >80. Median number of BM was 2 (1 to ≥99). The median OS for the ALK/EGFR+ NSCLC BM was 19.9 versus 10.1 months for the WT (P = 0.028). The number of BM in the EGFR/ALK+ group did not impact OS (BM = 1 with 21.1 months vs 2-3 with 19.1 months and >3 with 23.7 months, P = 0.74), whereas fewer BM in the WT cohort had significantly better OS (BM = 1 with 13.8 mo, 2-3 with 11.0 mo and >3 with 8.1 mo; P = 0.006) with the adjustment of age, KPS, symptoms from BM and synchronicity., Conclusions: Number of BM does not impact outcomes in the EGFR/ALK+ NSCLC patients, implying that targeted therapy along with surgery and/or radiation may improve OS irrespective of the number of BM. Number of BM, extracranial metastasis (ECM), and KPS independently affected OS/PFS in WT NSCLC BM, which was consistent with the known literature., (© The Author(s) 2019. Published by Oxford University Press on behalf of the Society for Neuro-Oncology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)
- Published
- 2020
- Full Text
- View/download PDF
19. Distinct clinical and biological implications of CUX1 in myeloid neoplasms.
- Author
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Aly M, Ramdzan ZM, Nagata Y, Balasubramanian SK, Hosono N, Makishima H, Visconte V, Kuzmanovic T, Adema V, Nazha A, Przychodzen BP, Kerr CM, Sekeres MA, Abazeed ME, Nepveu A, and Maciejewski JP
- Subjects
- Biomarkers, Chromosome Aberrations, Clonal Evolution genetics, Female, Gene Expression Profiling, Genetic Association Studies, Genetic Predisposition to Disease, Homeodomain Proteins metabolism, Humans, Kaplan-Meier Estimate, Leukocytes, Mononuclear, Loss of Heterozygosity, Male, Mutation, Myeloproliferative Disorders mortality, Myeloproliferative Disorders pathology, Phenotype, Polymorphism, Single Nucleotide, Prognosis, Repressor Proteins metabolism, Sequence Deletion, Transcription Factors metabolism, Disease Susceptibility, Homeodomain Proteins genetics, Myeloproliferative Disorders diagnosis, Myeloproliferative Disorders etiology, Repressor Proteins genetics, Transcription Factors genetics
- Abstract
Somatic mutations of the CUT-like homeobox 1 ( CUX1 ) gene ( CUX1
MT ) can be found in myeloid neoplasms (MNs), in particular, in myelodysplastic syndromes (MDSs). The CUX1 locus is also deleted in 3 of 4 MN cases with -7/del(7q). A cohort of 1480 MN patients was used to characterize clinical features and clonal hierarchy associated with CUX1MT and CUX1 deletions ( CUX1DEL ) and to analyze their functional consequences in vitro. CUX1MT were present in 4% of chronic MNs. CUX1DEL were preferentially found in advanced cases (6%). Most MDS and acute myeloid leukemia (AML) patients with -7/del(7q) and up to 15% of MDS patients and 5% of AML patients diploid for the CUX1 locus exhibited downmodulated CUX1 expression. In 75% of mutant cases, CUX1MT were heterozygous, whereas microdeletions and homozygous and compound-heterozygous mutations were less common. CUXMT/DEL were associated with worse survival compared with CUX1WT Within the clonal hierarchy, 1 of 3 CUX1MT served as founder events often followed by secondary BCOR and ASXL1 subclonal hits, whereas TET2 was the most common ancestral lesion, followed by subclonal CUX1MT Comet assay of patients' bone marrow progenitor cells and leukemic cell lines performed in various experimental conditions revealed that frameshift mutations, hemizygous deletions, or experimental CUX1 knockdown decrease the repair of oxidized bases. These functional findings may explain why samples with either CUX1MT or low CUX1 expression coincided with significantly higher numbers of somatic hits by whole-exome sequencing. Our findings implicate the DNA repair dysfunction resulting from CUX1 lesions in the pathogenesis of MNs, in which they lead to a mutator phenotype., (© 2019 by The American Society of Hematology.)- Published
- 2019
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20. The evolution of paroxysmal nocturnal haemoglobinuria depends on intensity of immunosuppressive therapy.
- Author
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Bat T, Abdelhamid ON, Balasubramanian SK, Mai A, Radivoyevitch T, Clemente M, and Maciejewski JP
- Subjects
- Adult, Aged, Anemia, Aplastic diagnosis, Cell Proliferation, Cell Size, Clone Cells pathology, Disease Progression, Hemoglobinuria, Paroxysmal diagnosis, Hemoglobinuria, Paroxysmal drug therapy, Humans, Middle Aged, Myelodysplastic Syndromes, Retrospective Studies, Anemia, Aplastic pathology, Hemoglobinuria, Paroxysmal etiology, Immunosuppression Therapy methods
- Published
- 2018
- Full Text
- View/download PDF
21. Efficacy of XP-endo Finisher files in endodontics.
- Author
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Kolli S, Balasubramanian SK, Kittappa K, and Mahalaxmi S
- Subjects
- Dental Instruments, Endodontics, Root Canal Preparation
- Published
- 2018
- Full Text
- View/download PDF
22. Distinct clinical and biological implications of various DNMT3A mutations in myeloid neoplasms.
- Author
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Balasubramanian SK, Aly M, Nagata Y, Bat T, Przychodzen BP, Hirsch CM, Adema V, Visconte V, Kuzmanovic T, Radivoyevitch T, Nazha A, Mukherjee S, Sekeres MA, and Maciejewski JP
- Subjects
- Aged, DNA Methyltransferase 3A, Female, Humans, Leukemia, Myeloid, Acute pathology, Male, Prognosis, DNA (Cytosine-5-)-Methyltransferases genetics, Leukemia, Myeloid, Acute genetics, Mutation genetics
- Published
- 2018
- Full Text
- View/download PDF
23. Rational management approach to pure red cell aplasia.
- Author
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Balasubramanian SK, Sadaps M, Thota S, Aly M, Przychodzen BP, Hirsch CM, Visconte V, Radivoyevitch T, and Maciejewski JP
- Subjects
- Adult, Aged, Aged, 80 and over, Alemtuzumab therapeutic use, Antineoplastic Agents therapeutic use, Bortezomib therapeutic use, Female, Humans, Immunoglobulins, Intravenous therapeutic use, Immunosuppressive Agents therapeutic use, Male, Middle Aged, Retrospective Studies, Algorithms, Disease Management, Red-Cell Aplasia, Pure therapy, Salvage Therapy methods
- Abstract
Pure red cell aplasia is an orphan disease, and as such lacks rationally established standard therapies. Most cases are idiopathic; a subset is antibody-mediated. There is overlap between idiopathic cases and those with T-cell large granular lymphocytic leukemia, hypogammaglobulinemia, and low-grade lymphomas. In each of the aforementioned, the pathogenetic mechanisms may involve autoreactive cytotoxic responses. We selected 62 uniformly diagnosed pure red cell aplasia patients and analyzed their pathophysiologic features and responsiveness to rationally applied first-line and salvage therapies in order to propose diagnostic and therapeutic algorithms that may be helpful in guiding the management of prospective patients, 52% of whom were idiopathic, while the others involved large granular lymphocytic leukemia, thymoma, and B-cell dyscrasia. T-cell-mediated responses ranged between a continuum from polyclonal to monoclonal (as seen in large granular lymphocytic leukemia). During a median observation period of 40 months, patients received a median of two different therapies to achieve remission. Frequently used therapy included calcineurin-inhibitors with a steroid taper yielding a first-line overall response rate of 76% (53/70). Oral cyclophosphamide showed activity, albeit lower than that produced by cyclosporine. Intravenous immunoglobulins were effective both in parvovirus patients and in hypogammaglobulinemia cases. In salvage settings, alemtuzumab is active, particularly in large granular lymphocytic leukemia-associated cases. Other potentially useful salvage options include rituximab, anti-thymocyte globulin and bortezomib. The workup of acquired pure red cell aplasia should include investigations of common pathological associations. Most effective therapies are directed against T-cell-mediated immunity, and therapeutic choices need to account for associated conditions that may help in choosing alternative salvage agents, such as intravenous immunoglobulin, alemtuzumab and bortezomib., (Copyright© 2018 Ferrata Storti Foundation.)
- Published
- 2018
- Full Text
- View/download PDF
24. Fanconi Anemia germline variants as susceptibility factors in aplastic anemia, MDS and AML.
- Author
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Przychodzen B, Makishima H, Sekeres MA, Balasubramanian SK, Thota S, Patel BJ, Clemente M, Hirsch C, Dienes B, and Maciejewski JP
- Abstract
Using next generation sequencing we have systematically analyzed a large cohort of 489 patients with bone marrow failure (BMF), including myelodysplastic syndrome (MDS), acute myeloid leukemia (AML), aplastic anemia (AA), and related conditions for the presence of germline (GL) alterations in Fanconi Anemia (FA) and telomerase genes. We have detected an increased frequency of heterozygous FA gene mutations in MDS and to lesser degree in AML suggesting that the presence of one normal allele may not be completely protective and indeed heterozygous FA lesions may have a long latency period before hematologic manifestation. In contrast, GL telomerase gene mutations were not associated with increased disease risk. When compared to large control cohorts, we have not detected an increased frequency of damaging variants among telomerase complex genes, including those previously believed to be involved in the pathogenesis of AA. Our results may suggest that while low penetrance and delayed disease onset can confound identification of genetic predisposition factors, GL FA alterations can be also associated with MDS., Competing Interests: CONFLICTS OF INTEREST The authors declare no conflicts of interest.
- Published
- 2017
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25. Clinical implications of somatic mutations in aplastic anemia and myelodysplastic syndrome in genomic age.
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Maciejewski JP and Balasubramanian SK
- Subjects
- Genomics, Humans, Anemia, Aplastic genetics, Anemia, Aplastic metabolism, Hemoglobinuria, Paroxysmal genetics, Hemoglobinuria, Paroxysmal metabolism, Mutation
- Abstract
Recent technological advances in genomics have led to the discovery of new somatic mutations and have brought deeper insights into clonal diversity. This discovery has changed not only the understanding of disease mechanisms but also the diagnostics and clinical management of bone marrow failure. The clinical applications of genomics include enhancement of current prognostic schemas, prediction of sensitivity or refractoriness to treatments, and conceptualization and selective application of targeted therapies. However, beyond these traditional clinical aspects, complex hierarchical clonal architecture has been uncovered and linked to the current concepts of leukemogenesis and stem cell biology. Detection of clonal mutations, otherwise typical of myelodysplastic syndrome, in the course of aplastic anemia (AA) and paroxysmal nocturnal hemoglobinuria has led to new pathogenic concepts in these conditions and created a new link between AA and its clonal complications, such as post-AA and paroxysmal nocturnal hemoglobinuria. Distinctions among founder vs subclonal mutations, types of clonal evolution (linear or branching), and biological features of individual mutations (sweeping, persistent, or vanishing) will allow for better predictions of the biologic impact they impart in individual cases. As clonal markers, mutations can be used for monitoring clonal dynamics of the stem cell compartment during physiologic aging, disease processes, and leukemic evolution., Competing Interests: Conflict-of-interest disclosure: The authors declare no competing financial interests., (© 2016 by The American Society of Hematology. All rights reserved.)
- Published
- 2017
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26. Outcome after heart transplantation from donation after circulatory-determined death donors.
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Messer S, Page A, Axell R, Berman M, Hernández-Sánchez J, Colah S, Parizkova B, Valchanov K, Dunning J, Pavlushkov E, Balasubramanian SK, Parameshwar J, Omar YA, Goddard M, Pettit S, Lewis C, Kydd A, Jenkins D, Watson CJ, Sudarshan C, Catarino P, Findlay M, Ali A, Tsui S, and Large SR
- Subjects
- Adolescent, Adult, Brain Death, Female, Graft Survival, Humans, Male, Middle Aged, Retrospective Studies, Survival Rate trends, Transplantation, Homologous, United Kingdom epidemiology, Young Adult, Heart Transplantation mortality, Perfusion methods, Registries, Tissue Donors, Tissue and Organ Procurement methods
- Abstract
Background: The requirement for heart transplantation is increasing, vastly outgrowing the supply of hearts available from donation after brain death (DBD) donors. Transplanting hearts after donation after circulatory-determined death (DCD) may be a viable additive alternative to DBD donors. This study compared outcomes from the largest single-center experience of DCD heart transplantation against matched DBD heart transplants., Methods: DCD hearts were retrieved using normothermic regional perfusion (NRP) or direct procurement and perfusion (DPP). During NRP, perfusion was restored to the arrested heart within the donor with the exclusion of the cerebral circulation, whereas DPP hearts were removed directly. All hearts were maintained on machine perfusion during transportation. A retrospective cohort of DBD heart transplants, matched for donor and recipient characteristics, was used as a comparison group. The primary outcome measure of this study (set by the United Kingdom regulatory body) was 90-day survival., Results: There were 28 DCD heart transplants performed during the 25-month study period. Survival at 90 days was not significantly different between DCD and matched DBD transplant recipients (DCD, 92%; DBD, 96%; p = 1.0). Hospital length of stay, treated rejection episodes, allograft function, and 1-year survival (DCD, 86%; DBD, 88%; p = 0.98) were comparable between groups. The method of retrieval (NRP or DPP) was not associated with a difference in outcome., Conclusions: These results suggest that heart transplantation from DCD heart donation provides comparable short-term outcomes to traditional DBD heart transplants and can serve to increase heart transplant activity in well-selected patients., (Copyright © 2017 International Society for Heart and Lung Transplantation. Published by Elsevier Inc. All rights reserved.)
- Published
- 2017
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27. Modulatory effect of dianthrone rich alcoholic flower extract of Cassia auriculata L. on experimental diabetes.
- Author
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Khader SZA, Syed Zameer Ahmed S, Balasubramanian SK, Arunachalam TK, Kannappan G, Mahboob MR, Ponnusamy P, and Ramesh K
- Abstract
Background: Diabetes is rapidly rising all over the world at an alarming rate and has changed from a mild disorder to major causes of mortality and morbidity in the youth and middle-aged people, and the prevalence is seen especially in six inhabited continents of the globe. The present study aims to explore the antidiabetic, lipid lowering effect of Cassia auriculata L. flowers in alloxan-induced diabetes., Methods: Diabetes was induced using alloxan monohydrate in experimental rats and subsequent therapeutic effects of C. auriculata extract and standard drug glibenclamide were monitored. Bioassay-directed fractionation using silica gel column chromatography was performed until pure fractions were isolated. The effect of the treatment was analyzed by hematological parameters and enzyme assays. The pure compounds were confirmed with thin layer chromatography and high performance liquid chromatography pattern and further subjected for characterization., Results: The alterations in blood glucose were monitored throughout the study. There was a gradual fall in blood glucose and significant changes were observed in lipid profile and metabolic enzyme after treatment with C. auriculata . Bioassay fractionation represented that the C2 subfraction produced a dose-dependent fall in blood glucose and lipid profile and upon further purification yielded two pure compounds. The structure of the pure compound was elucidated using Fourier transform infrared,
1 H nuclear magnetic resonance,13 C nuclear magnetic resonance, and mass spectral data., Conclusion: The present study clearly indicated the significant antidiabetic effect of C. auriculata and lends support for its traditional usage without evident toxic effects.- Published
- 2017
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28. Management of Brain Metastases in Tyrosine Kinase Inhibitor-Naïve Epidermal Growth Factor Receptor-Mutant Non-Small-Cell Lung Cancer: A Retrospective Multi-Institutional Analysis.
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Magnuson WJ, Lester-Coll NH, Wu AJ, Yang TJ, Lockney NA, Gerber NK, Beal K, Amini A, Patil T, Kavanagh BD, Camidge DR, Braunstein SE, Boreta LC, Balasubramanian SK, Ahluwalia MS, Rana NG, Attia A, Gettinger SN, Contessa JN, Yu JB, and Chiang VL
- Subjects
- Aged, Brain Neoplasms genetics, Brain Neoplasms secondary, Carcinoma, Non-Small-Cell Lung genetics, Carcinoma, Non-Small-Cell Lung secondary, Combined Modality Therapy, Cranial Irradiation, Disease-Free Survival, ErbB Receptors genetics, Female, Humans, Lung Neoplasms genetics, Male, Middle Aged, Radiosurgery, Retrospective Studies, Salvage Therapy, Survival Rate, Antineoplastic Agents therapeutic use, Brain Neoplasms therapy, Carcinoma, Non-Small-Cell Lung therapy, ErbB Receptors antagonists & inhibitors, Erlotinib Hydrochloride therapeutic use, Lung Neoplasms pathology, Protein Kinase Inhibitors therapeutic use
- Abstract
Purpose Stereotactic radiosurgery (SRS), whole-brain radiotherapy (WBRT), and epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitors (TKIs) are treatment options for brain metastases in patients with EGFR-mutant non-small-cell lung cancer (NSCLC). This multi-institutional analysis sought to determine the optimal management of patients with EGFR-mutant NSCLC who develop brain metastases and have not received EGFR-TKI. Materials and Methods A total of 351 patients from six institutions with EGFR-mutant NSCLC developed brain metastases and met inclusion criteria for the study. Exclusion criteria included prior EGFR-TKI use, EGFR-TKI resistance mutation, failure to receive EGFR-TKI after WBRT/SRS, or insufficient follow-up. Patients were treated with SRS followed by EGFR-TKI, WBRT followed by EGFR-TKI, or EGFR-TKI followed by SRS or WBRT at intracranial progression. Overall survival (OS) and intracranial progression-free survival were measured from the date of brain metastases. Results The median OS for the SRS (n = 100), WBRT (n = 120), and EGFR-TKI (n = 131) cohorts was 46, 30, and 25 months, respectively ( P < .001). On multivariable analysis, SRS versus EGFR-TKI, WBRT versus EGFR-TKI, age, performance status, EGFR exon 19 mutation, and absence of extracranial metastases were associated with improved OS. Although the SRS and EGFR-TKI cohorts shared similar prognostic features, the WBRT cohort was more likely to have a less favorable prognosis ( P = .001). Conclusion This multi-institutional analysis demonstrated that the use of upfront EGFR-TKI, and deferral of radiotherapy, is associated with inferior OS in patients with EGFR-mutant NSCLC who develop brain metastases. SRS followed by EGFR-TKI resulted in the longest OS and allowed patients to avoid the potential neurocognitive sequelae of WBRT. A prospective, multi-institutional randomized trial of SRS followed by EGFR-TKI versus EGFR-TKI followed by SRS at intracranial progression is urgently needed.
- Published
- 2017
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29. A Comparative Study of the Quality of Apical Seal in Resilon/Epiphany SE Following Intra canal Irrigation With 17% EDTA, 10% Citric Acid, And MTAD as Final Irrigants - A Dye Leakage Study Under Vacuum.
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Balasubramanian SK, Saraswathi V, Ballal NV, Acharya SR, Sampath JS, and Singh S
- Abstract
Introduction: Adequate apical sealing ability of the root canal filling material is an essential requisite for a successful endodontic therapy. Various endodontic irrigants are used for the removal of smear layer before obturating with a solid core material, thereby, reducing microleakage and improving apical seal. Resilon, a synthetic material was developed as an alternative to replace the conventional gutta-percha (standard root canal filling material) and traditional sealers for the obturation of endodontically treated teeth., Aim: To evaluate and compare in-vitro, the post obturation apical seal obtained with Resilon /Epiphany SE (Self Etch) sealer following irrigation with 17% Ethylenediamine Tetra-Acetic Acid (EDTA), 10% citric acid, and MTAD (a mixture of doxycycline, citric acid, and a detergent, Tween 80), as final irrigants in combination with Sodium hypochlorite (NaOCl) using dye leakage under vacuum method., Materials and Methods: Fifty five single rooted human maxillary central incisors were subjected to root canal instrumentation. Based on the final irrigation solution, samples were divided into three experimental groups (n=15); (I) 17% EDTA + 1.3% NaOCl, (II) 10% citric acid + 1.3% NaOCl, (III) MTAD + 1.3% NaOCl and two control groups (positive and negative) with 0.9% normal saline as a final irrigant. The samples were obturated with resilon/epiphany SE sealer according to manufacturer instructions and placed in 2% rhodamine B dye solution under vacuum pressure for 30 minutes and allowed to remain in the dye for seven days. All samples were then longitudinally split and examined for dye leakage under stereomicroscope and the data were statistically analysed using one-way ANOVA and post hoc tukey test., Results: Statistically significant difference (p=0.001) was observed in the mean apical leakage between the experimental and the control groups. However, there was no significant difference (p>0.05) observed in the mean apical leakage amongst the three experimental groups., Conclusion: 17% EDTA, 10% citric acid, and MTAD were equally effective in achieving the post-obturation apical seal with resilon/epiphany SE sealer when used as a final irrigant in combination with NaOCl.
- Published
- 2017
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30. Longitudinal experience with WHO Grade III (anaplastic) meningiomas at a single institution.
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Balasubramanian SK, Sharma M, Silva D, Karivedu V, Schmitt P, Stevens GH, Barnett GH, Prayson RA, Elson P, Suh JH, Murphy ES, and Chao ST
- Subjects
- Aged, Aged, 80 and over, Female, Humans, Longitudinal Studies, Male, Meningeal Neoplasms pathology, Meningeal Neoplasms therapy, Meningioma pathology, Meningioma therapy, Middle Aged, Neoplasm Grading, Retrospective Studies, Survival Analysis, Treatment Outcome, World Health Organization, Meningeal Neoplasms epidemiology, Meningioma epidemiology
- Abstract
To retrospectively analyze and assess the outcomes and prognostic factors in patients with anaplastic meningioma (AM) (WHO Grade III). Clinical data and outcome [overall (OS) and progression-free (PFS) survival] from 18 patients with Grade III meningioma (AM, based on World Health Organization 2016 definition) initially treated between March 2000 and June 2015 were analyzed. Eleven patients (61%) were male, median age at diagnosis was 63 (range 48-86), and 55% (10/18 patients) had good performance status (KPS ≥ 80). Eight patients (45%) had lower grade disease (Grade I-n = 2; Grade II-n = 6) prior to being upgraded to AM. Ten patients had fractionated radiation after primary surgery, eight patients had salvage fractionated RT, stereotactic radiosurgery (SRS) boost along with primary RT in 1 patient, and salvage SRS to 18 separate areas in 14 patients. Salvage chemotherapy was mainly considered in third or fourth recurrences. 13 (72%) patients recurred and 10 (56%) have died. Median PFS was 14.5 months (95% CI 6.9-22.2). The 5-year survival rate was 40 ± 15% and median OS was 55.8 months (95% CI 27.7-80.3). Of all factors examined, only Karnofsky performance status (KPS) affected outcome (PFS p = 0.0003; OS p = 0.0003). With median OS of 55 months (4.6 years) our results are consistent with existing reports of the poor outcomes for AM patients. From the available data, surgical resection followed by RT and salvage radiosurgery and/or chemotherapy can lead to extended survival; however the benefit may decrease with successive treatments.
- Published
- 2017
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31. Safe intrapulpal anaesthesia.
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Balasubramanian SK and Natanasabapathy V
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- Anesthetics, Local administration & dosage, Humans, Injections methods, Lidocaine administration & dosage, Lidocaine therapeutic use, Pain Management, Pulpitis, Sodium Hypochlorite administration & dosage, Sodium Hypochlorite therapeutic use, Anesthesia, Dental methods, Anesthesia, Local methods, Dental Pulp drug effects
- Published
- 2017
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32. Does the periodontal status of peg-shaped mandibular central incisor affect its prognosis?
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Balasubramanian SK, Sekar M, Vinayachandran D, and Natanasabapathy V
- Abstract
Competing Interests: There are no conflicts of interest.
- Published
- 2017
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33. Clinical Considerations of Intrapulpal Anesthesia in Pediatric Dentistry.
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Balasubramanian SK, Natanasabapathy V, and Vinayachandran D
- Published
- 2017
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34. Inflammatory Changes in Lung Tissues Associated with Altered Inflammation-Related MicroRNA Expression after Intravenous Administration of Gold Nanoparticles in Vivo .
- Author
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Ng CT, Li JJ, Balasubramanian SK, You F, Yung LL, and Bay BH
- Abstract
Potential adverse effects of gold nanoparticles (AuNPs) are gaining attention due to their wide industrial, consumer, and biomedical applications. This may give rise to possible health risks from direct exposure to the NPs. Excessive inflammatory response is known to be one of the main effects induced by NPs. In this study, inflammatory and miRNA expression changes in lung tissues were evaluated in rats following intravenous administration of AuNPs. AuNPs (20 nm) at a mass concentration of 256 μg/mL were intravenously injected into 6-8 week old male Wistar rats at single doses of 0.025, 0.05, 0.1, and 0.2 mg/kg and sacrificed at 1 week, 1 month, and 2 months, respectively. The biodistribution of AuNPs in the lungs of the rats was determined by inductively coupled plasma mass spectrometry. There were no apparent changes observed in the body weight of the experimental rats. Histopathological examination revealed the presence of infiltrating lymphocytes in lung interstitial tissues and enhanced IL-1α immunostaining in the lung tissues. Out of 84 rat microRNAs (miRNAs) analyzed, the expression of three miRNAs in rat lungs were dysregulated by more than 2-fold in the 0.1 and 0.2 mg/kg AuNP-treated rats 1 week after exposure. In particular, miR-327 was significantly down-regulated in both groups of treated rats. Taken together, it would seem that miRNAs may regulate inflammatory changes in the lungs after exposure to AuNPs in vivo .
- Published
- 2016
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35. Correlated parameter fit of arrhenius model for thermal denaturation of proteins and cells.
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Qin Z, Balasubramanian SK, Wolkers WF, Pearce JA, and Bischof JC
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- Cell Line, Cell Line, Tumor, Collagen chemistry, Hot Temperature, Humans, Peptide Fragments chemistry, Serum Albumin, Bovine chemistry, Spectroscopy, Fourier Transform Infrared, Models, Biological, Protein Denaturation
- Abstract
Thermal denaturation of proteins is critical to cell injury, food science and other biomaterial processing. For example protein denaturation correlates strongly with cell death by heating, and is increasingly of interest in focal thermal therapies of cancer and other diseases at temperatures which often exceed 50 °C. The Arrhenius model is a simple yet widely used model for both protein denaturation and cell injury. To establish the utility of the Arrhenius model for protein denaturation at 50 °C and above its sensitivities to the kinetic parameters (activation energy E a and frequency factor A) were carefully examined. We propose a simplified correlated parameter fit to the Arrhenius model by treating E a, as an independent fitting parameter and allowing A to follow dependently. The utility of the correlated parameter fit is demonstrated on thermal denaturation of proteins and cells from the literature as a validation, and new experimental measurements in our lab using FTIR spectroscopy to demonstrate broad applicability of this method. Finally, we demonstrate that the end-temperature within which the denaturation is measured is important and changes the kinetics. Specifically, higher E a and A parameters were found at low end-temperature (50 °C) and reduce as end-temperatures increase to 70 °C. This trend is consistent with Arrhenius parameters for cell injury in the literature that are significantly higher for clonogenics (45-50 °C) vs. membrane dye assays (60-70 °C). Future opportunities to monitor cell injury by spectroscopic measurement of protein denaturation are discussed.
- Published
- 2014
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36. The effect of primary particle size on biodistribution of inhaled gold nano-agglomerates.
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Balasubramanian SK, Poh KW, Ong CN, Kreyling WG, Ong WY, and Yu LE
- Subjects
- Animals, Biological Transport, Gene Expression Regulation, Hippocampus metabolism, Male, Metal Nanoparticles ultrastructure, Nanotechnology, Organ Specificity, Rats, Rats, Wistar, Tissue Distribution, Gold administration & dosage, Inhalation Exposure analysis, Metal Nanoparticles administration & dosage, Particle Size
- Abstract
Airborne engineered nanoparticles undergo agglomeration, and careful distinction must be made between primary and agglomerate size of particles, when assessing their health effects. This study compares the effects on rats undergoing 15-day inhalation exposure to airborne agglomerates of gold nanoparticles (AuNPs) of similar size distribution and number concentration (1 × 10(6) particles/cm(3)), but two different primary diameters of 7 nm or 20 nm. Inhalation of agglomerates containing 7-nm AuNPs resulted in highest deposition by mass concentration in the lungs, followed by brain regions including the olfactory bulb, hippocampus, striatum, frontal cortex, entorhinal cortex, septum, cerebellum; aorta, esophagus, and kidney. Eight organs/tissues especially the brain retained greater mass concentration of Au after inhalation exposure to agglomerates of 7-nm than 20-nm AuNPs. Macrophage mediated escalation followed by fecal excretion is the major pathway of clearing inhaled AuNPs in the lungs. Microarray analyses of the hippocampus showed mostly downregulated genes, related to the cytoskeleton and neurite outgrowth. Together, results in this study indicate disintegration of nanosized agglomerates after inhalation and show impact of primary size of particles on subsequent biodistribution., (Copyright © 2013 Elsevier Ltd. All rights reserved.)
- Published
- 2013
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37. Characterization, purification, and stability of gold nanoparticles.
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Balasubramanian SK, Yang L, Yung LY, Ong CN, Ong WY, and Yu LE
- Subjects
- Centrifugation, Metal Nanoparticles ultrastructure, Oxidation-Reduction, Particle Size, Photoelectron Spectroscopy, Solutions, Suspensions, Gold chemistry, Gold isolation & purification, Metal Nanoparticles chemistry
- Abstract
Impurities in the synthesized gold nanoparticle (AuNP) solution are systematically identified followed by determining an optimal purification process and evaluating the stability as well as oxidation state of the purified 20-nm AuNPs. Quantified non-AuNP components and a newly speciated byproduct (acetate) complete the stoichiometric equation of AuNP synthesis through the citrate reduction method. Among the five tested centrifugation forces (3000-11,000g) and durations (10-60 min), optimal purification of AuNPs was achieved by centrifugation operating at 7000 g for 20 min which satisfactorily recovers ∼80% of AuNPs without detectable impurities. Storage in the dark at 4 °C prolongs the stability of the purified AuNP suspensions up to 20 days. AuNPs employed in this study persist in their atomic status without being oxidized, even after they were aerosolized in air or heated at 500 °C. This work demonstrates how impurities are identified and removed, and the purified AuNPs can be a reference material to evaluate toxicity or reactivity of other engineered nanomaterials., (Copyright © 2010 Elsevier Ltd. All rights reserved.)
- Published
- 2010
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38. Biodistribution of gold nanoparticles and gene expression changes in the liver and spleen after intravenous administration in rats.
- Author
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Balasubramanian SK, Jittiwat J, Manikandan J, Ong CN, Yu LE, and Ong WY
- Subjects
- Animals, Injections, Intravenous, Liver cytology, Male, Oligonucleotide Array Sequence Analysis, Rats, Rats, Wistar, Spleen cytology, Tissue Distribution, Gene Expression drug effects, Gold administration & dosage, Gold metabolism, Gold pharmacology, Liver metabolism, Metal Nanoparticles administration & dosage, Metal Nanoparticles chemistry, Spleen metabolism
- Abstract
Biodistribution of gold nanoparticles (AuNPs) in more than 25 organs were examined on 1 day, 1 week, 1 month and 2 months after a single intravenous (i.v.) injection in rats. Au was rapidly and consistently accumulated in liver (49.4+/-50.4-72.2+/-40.5 ng/g) and spleen (8.4+/-5.0-9.5+/-6.4 ng/g) throughout the entire timeframe of the study (2 months). Significant accumulation of Au in kidney (up to 5.5+/-2.5 ng/g) and testis (up to 0.6+/-0.1 ng/g) occurred from 1 month post-injection when Au level in urine and feces decreased. Significant increase of Au in blood occurred 2 months after injection, coincident with the delayed accumulation in kidney. Au accumulation in lungs was found at 1 day post-injection but decreased within a week. No accumulation of Au was found in the brain. Microarray results of liver and spleen point to significant effects on genes related to detoxification, lipid metabolism, cell cycle, defense response, and circadian rhythm. These results demonstrate that significant biodistribution of Au occurs in the body over 2 months after a single i.v. injection of AuNPs, accompanied by gene expression changes in target organs., (Copyright (c) 2009 Elsevier Ltd. All rights reserved.)
- Published
- 2010
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39. Membrane hydration correlates to cellular biophysics during freezing in mammalian cells.
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Balasubramanian SK, Wolkers WF, and Bischof JC
- Subjects
- Animals, Biophysical Phenomena, Cell Line, Tumor, Cell Membrane chemistry, Cell Survival, Cells, Cultured, Fibroblasts metabolism, Freezing, Humans, Ice, Male, Membrane Lipids metabolism, Models, Biological, Myocytes, Smooth Muscle metabolism, Prostatic Neoplasms metabolism, Spectroscopy, Fourier Transform Infrared, Swine, Thermodynamics, Water chemistry, Water metabolism, Cell Membrane metabolism
- Abstract
Cell survival during freezing applications in biomedicine is highly correlated to the temperature history and its dependent cellular biophysical events of dehydration and intracellular ice formation (IIF). Although cell membranes are known to play a significant role in cell injury, a clear correlation between the membrane state and the surrounding intracellular and extracellular water is still lacking. We previously showed that lipid hydration in LNCaP tumor cells is related to cellular dehydration. The goal of this study is to build upon this work by correlating both the phase state of the membrane and the surrounding water to cellular biophysical events in three different mammalian cell types: human prostate tumor cells (LNCaP), human dermal fibroblasts (HDF), and porcine smooth muscle cells (SMC) using Fourier Transform Infrared spectroscopy (FTIR). Variable cooling rates were achieved by controlling the degree of supercooling prior to ice nucleation (-3 degrees C and -10 degrees C) while the sample was cooled at a set rate of 2 degrees C/min. Membranes displayed a highly cooperative phase transition under dehydrating conditions (i.e. NT=-3 degrees C), which was not observed under IIF conditions (NT=-10 degrees C). Spectral analysis showed a consistently greater amount of ice formation during dehydrating vs. IIF conditions in all cell types. This is hypothesized to be due to the extreme loss of membrane hydration in dehydrating cells that is manifested as excess water available for phase change. Interestingly, changes in residual membrane conformational disorder correlate strongly with cellular volumetric decreases as assessed by cryomicroscopy. A strong correlation was also found between the activation energies for freezing induced lyotropic membrane phase change determined using FTIR and the water transport measured by cryomicroscopy. Reduced lipid hydration under dehydration freezing conditions is suggested as one of the likely causes of what has been termed as "solution effects" injury in cryobiology.
- Published
- 2009
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40. Thermal injury prediction during cryoplasty through in vitro characterization of smooth muscle cell biophysics and viability.
- Author
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Balasubramanian SK, Venkatasubramanian RT, Menon A, and Bischof JC
- Subjects
- Animals, Apoptosis, Burns pathology, Cell Survival, Cells, Cultured, Computer Simulation, Muscle, Smooth, Vascular pathology, Muscle, Smooth, Vascular surgery, Swine, Burns etiology, Burns physiopathology, Cryosurgery adverse effects, Models, Cardiovascular, Muscle, Smooth, Vascular injuries, Muscle, Smooth, Vascular physiopathology, Myocytes, Smooth Muscle pathology
- Abstract
Restenosis in peripheral arteries is a major health care problem in the United States. Typically, 30-40% of angioplasties result in restenosis and hence alternative treatment techniques are being actively investigated. Cryoplasty, a novel technique involving simultaneous stretching and freezing of the peripheral arteries (e.g., femoral, iliac, popliteal) using a cryogen-filled balloon catheter, has shown the potential to combat restenosis. However, evaluation of the thermal and biophysical mechanisms that affect cellular survival during cryoplasty is lacking. To achieve this, the thermal history in arteries was predicted for different balloon temperatures using a thermal model. Cellular biophysical responses (water transport (WT) and intracellular ice formation (IIF)) were then characterized, using in vitro model systems, based on the thermal model predictions. The thermal and biophysical effects on cell survival were eventually determined. For this study, smooth muscle cells (SMC) isolated from porcine femoral arteries were used in suspensions and attached in vitro systems (monolayer and fibrin gel). Results showed that for different balloon temperatures, the thermal model predicted cooling rates from 2200 to 5 degrees C/min in the artery. Biophysical parameters (WT & IIF) were higher for SMCs in attached systems as compared to suspensions. The "combined" fit WT parameters for SMCs in suspension (at 5, 10, and 25 degrees C/min) are L (pg) = 0.12 microm/(min atm) and E (Lp) = 24.1 kcal/mol. Individual WT parameters for SMCs in attached cell systems at higher cooling rates are approximately an order of magnitude higher compared to suspensions (e.g., at 130 degrees C/min, WT parameters in monolayer and fibrin TE systems are L (pg) = 18.6, 19.4 microm/(min atm) and E (Lp) = 112, 127 kcal/mol, respectively). Similarly, IIF parameters assessed at 130 degrees C/min are higher for SMCs in attached systems than suspensions (Omega 0 = 1.1, 354, 378 (x 10(8) (1/m(2) s)) and kappa(o) = 1.6, 1.8, 2.1 (x 10(9) K(5)) for suspensions, monolayer, and fibrin TE, respectively). One possible reason for the differences in IIF kinetics was verified to be the presence of gap junctions, which facilitate cell-cell connections through which ice can propagate. This is reflected by the change in the predicted IIF parameters when a gap junction inhibitor was added and tested in monolayer (Omega 0 (1/m(2) s)); kappa(o) = 2.1 x 10(9) K(5)). SMC viability was affected by the model system (lower viability in attached systems), the thermal conditions and the biophysics. For e.g., IIF is lethal to cells and SMC viability was verified to be the least in fibrin TE (most % IIF) and the most in suspensions (least % IIF) at all cooling rates. Using the results from the fibrin TE (suggested as the best in vitro system to mimic a restenosis environment), conservative estimates of injury regimes in the artery during cryoplasty is predicted. The results can be used to suggest future optimizations and modifications during cryoplasty and also to design future in vivo studies.
- Published
- 2008
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41. Microwave surgical ablation for atrial fibrillation during off-pump coronary artery surgery using total arterial-Y-grafts: an early experience.
- Author
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Balasubramanian SK, Theologou T, and Birdi I
- Subjects
- Aged, Aged, 80 and over, Atrial Fibrillation complications, Coronary Artery Disease complications, Coronary Artery Disease surgery, Female, Humans, Male, Mammary Arteries surgery, Microwaves, Middle Aged, Radial Artery transplantation, Atrial Fibrillation surgery, Catheter Ablation, Coronary Artery Bypass, Off-Pump methods
- Abstract
This study demonstrates the efficacy and eligibility of concomitant epicardial microwave AF (MWAF) ablation during off-pump arterial revascularisation using the left internal mammary to radial 'Y' graft (OPCABy) in patients with permanent and paroxysmal atrial fibrillation. From June 2004 to December 2005, sixteen consecutive patients were offered MWAF ablation and OPCABy. AF was permanent in 11 cases and paroxysmal in five. The MWAF ablation protocol exploited the use of either the Flex 4 or Flex 10 probe (Afx- Guidant, Santa Clara, CA). Spontaneous cardioversion was used to demonstrate conduction block. Data were collected prospectively. Patients were followed-up in outpatient clinic at 6 weeks, 3 months and 6 months after discharge. Sinus rhythm was seen in 75%, 67% and 71% of patients at conclusion of surgery, and 3 and 6 months postoperatively. Cardioversion to sinus rhythm was seen in 67% of patients with permanent AF and 80% of patients with paroxysmal AF. Spontaneous cardioversion at operation occurred in 12 patients, all of whom were in sinus rhythm at six months. The use of MWAF ablation during concomitant OPCABy surgery is an effective therapy in the short- to medium-term. Spontaneous return to sinus rhythm is a reliable intraoperative indicator of long-term success.
- Published
- 2007
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42. Pseudocalcification on chest CT scan.
- Author
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Tiruvoipati R, Balasubramanian SK, Entwisle JJ, Firmin RK, and Peek GJ
- Subjects
- Child, Diagnosis, Differential, Extracorporeal Membrane Oxygenation, Female, Fluorocarbons administration & dosage, Humans, Liquid Ventilation, Respiration, Artificial methods, Respiratory Insufficiency complications, Respiratory Insufficiency diagnostic imaging, Respiratory Insufficiency therapy, Tuberculosis, Miliary complications, Tuberculosis, Miliary diagnostic imaging, Tuberculosis, Miliary therapy, Calcinosis diagnostic imaging, Lung diagnostic imaging, Lung Diseases diagnostic imaging, Tomography, X-Ray Computed
- Abstract
Liquid ventilation with perfluorocarbons is used in severe respiratory failure that cannot be managed by conventional methods. Very little is known about the use of liquid ventilation in paediatric patients with respiratory failure and there are no reports describing the distribution and excretion of perfluorocarbons in paediatric patients with severe respiratory failure. The aim of this report is to highlight the prolonged retention of perfluorocarbons in a paediatric patient, mimicking pulmonary calcification and misleading the interpretation of the chest CT scan. A 10-year-old girl was admitted to our intensive care unit with severe respiratory failure due to miliary tuberculosis. Extracorporeal membrane oxygenation (ECMO) was used to support gas exchange and partial liquid ventilation (PLV) with perfluorodecalin was used to aid in oxygenation, lavage the lungs and clear thick secretions. The patient developed a pneumothorax (fluorothorax) on the next day and PLV was discontinued. Multiple bronchoalveolar lavages were performed to clear thick secretions. With no improvement in lung function over the next month a CT scan of the chest was performed. This revealed extensive pulmonary fibrosis and multiple high attenuation lesions suggestive of pulmonary calcification. To exclude perfluorodecalin as the cause for high attenuation lesions, a sample of perfluorodecalin was scanned to estimate the Hounsfield unit density, which was similar to the density of high attenuation lesions on chest CT scan. High-density opacification should be interpreted with caution, especially following liquid ventilation.
- Published
- 2007
- Full Text
- View/download PDF
43. Extracorporeal membrane oxygenation and extracorporeal albumin dialysis in pediatric patients with sepsis and multi-organ dysfunction syndrome.
- Author
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Tiruvoipati R, Moorthy T, Balasubramanian SK, Platt V, and Peek GJ
- Subjects
- Adolescent, Albumins, Child, Preschool, Female, Humans, Infant, Male, Treatment Outcome, Extracorporeal Membrane Oxygenation, Multiple Organ Failure etiology, Multiple Organ Failure therapy, Renal Dialysis, Sepsis complications
- Abstract
Extracorporeal membrane oxygenation (ECMO) is used in managing patients with potentially reversible cardio-respiratory failure refractory to conventional methods. Multiorgan dysfunction syndrome (MODS), usually due to sepsis, remains the main cause of mortality in such patients. We report a series of six pediatric patients with sepsis-induced MODS where extracorporeal albumin dialysis (EAD) was used while the patients were on ECMO. The age of the patients ranged between 1 month and 17 years. The mean pediatric index of mortality (PIM) score at admission was 67.5%. All these patients further deteriorated with MODS and EAD was used as rescue therapy. At institution of EAD, 4 patients had dysfunction of 4 organs and 2 patients had dysfunction of 5 organs. The number of EAD cycles ranged between 1 and 3. Three out of the 6 patients (50%) survived to discharge from the intensive care unit and two of the six patients (33%) survived to hospital discharge. According to our previous experience and published results, all these patients would have been expected to die. The present results suggest that EAD may prove to have a role in the treatment of pediatric patients with sepsis-induced MODS. Further research is required to identify the group of patients who would benefit most by EAD as well as understand the clearance of inflammatory mediators and other mechanisms involved with the use of EAD.
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- 2007
- Full Text
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44. Effects of freezing on membranes and proteins in LNCaP prostate tumor cells.
- Author
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Wolkers WF, Balasubramanian SK, Ongstad EL, Zec HC, and Bischof JC
- Subjects
- Biophysical Phenomena, Biophysics, Cell Line, Tumor, Cell Survival physiology, Freezing, Gels, Hot Temperature, Humans, Male, Phase Transition, Protein Conformation, Protein Denaturation, Protein Structure, Secondary, Spectroscopy, Fourier Transform Infrared, Cryopreservation, Neoplasm Proteins analysis, Prostatic Neoplasms pathology
- Abstract
Fourier transform infrared spectroscopy (FTIR) and cryomicroscopy were used to define the process of cellular injury during freezing in LNCaP prostate tumor cells, at the molecular level. Cell pellets were monitored during cooling at 2 degrees C/min while the ice nucleation temperature was varied between -3 and -10 degrees C. We show that the cells tend to dehydrate precipitously after nucleation unless intracellular ice formation occurs. The predicted incidence of intracellular ice formation rapidly increases at ice nucleation temperatures below -4 degrees C and cell survival exhibits an optimum at a nucleation temperature of -6 degrees C. The ice nucleation temperature was found to have a great effect on the membrane phase behavior of the cells. The onset of the liquid crystalline to gel phase transition coincided with the ice nucleation temperature. In addition, nucleation at -3 degrees C resulted in a much more co-operative phase transition and a concomitantly lower residual conformational disorder of the membranes in the frozen state compared to samples that nucleated at -10 degrees C. These observations were explained by the effect of the nucleation temperature on the extent of cellular dehydration and intracellular ice formation. Amide-III band analysis revealed that proteins are relatively stable during freezing and that heat-induced protein denaturation coincides with an abrupt decrease in alpha-helical structures and a concomitant increase in beta-sheet structures starting at an onset temperature of approximately 48 degrees C.
- Published
- 2007
- Full Text
- View/download PDF
45. Factors influencing the outcome of paediatric cardiac surgical patients during extracorporeal circulatory support.
- Author
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Balasubramanian SK, Tiruvoipati R, Amin M, Aabideen KK, Peek GJ, Sosnowski AW, and Firmin RK
- Subjects
- Child, Child, Preschool, Heart Defects, Congenital mortality, Hospital Mortality, Humans, Infant, Prognosis, Retrospective Studies, Risk Factors, Treatment Outcome, Extracorporeal Membrane Oxygenation, Heart Defects, Congenital surgery
- Abstract
Background: Veno-arterial extracorporeal membrane oxygenation (ECMO) is a common modality of circulatory assist device used in children. We assessed the outcome of children who had ECMO following repair of congenital cardiac defects (CCD) and identified the risk factors associated with hospital mortality., Methods: From April 1990 to December 2003, 53 patients required ECMO following surgical correction of CCD. Retrospectively collected data was analyzed with univariate and multivariate logistic regression analysis., Results: Median age and weight of the patients were 150 days and 5.4 kgs respectively. The indications for ECMO were low cardiac output in 16, failure to wean cardiopulmonary bypass in 13, cardiac arrest in 10 and cardio-respiratory failure in 14 patients. The mean duration of ECMO was 143 hours. Weaning off from ECMO was successful in 66% and of these 83% were survival to hospital-discharge. 37.7% of patients were alive for the mean follow-up period of 75 months. On univariate analysis, arrhythmias, ECMO duration >168 hours, bleeding complications, renal replacement therapy on ECMO, arrhythmias and cardiac arrest after ECMO were associated with hospital mortality.On multivariate analysis, abnormal neurology, bleeding complications and arrhythmias after ECMO were associated with hospital mortality. Extra and intra-thoracic cannulations were used in 79% and 21% of patients respectively and extra-thoracic cannulation had significantly less bleeding complications (p = 0.031)., Conclusion: ECMO provides an effective circulatory support following surgical repair of CCD in children. Extra-thoracic cannulation is associated with less bleeding complications. Abnormal neurology, bleeding complications on ECMO and arrhythmias after ECMO are poor prognostic indicators for hospital survival.
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- 2007
- Full Text
- View/download PDF
46. Water transport and IIF parameters for a connective tissue equivalent.
- Author
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Balasubramanian SK, Bischof JC, and Hubel A
- Subjects
- Biophysics methods, Cells, Cultured, Collagen metabolism, Evaluation Studies as Topic, Fibrin metabolism, Fibroblasts metabolism, Freezing, Humans, Ice analysis, Skin metabolism, Temperature, Tissue Preservation methods, Biological Transport physiology, Connective Tissue metabolism, Cryopreservation, Water metabolism
- Abstract
Understanding the biophysical processes that govern freezing injury of a tissue equivalent (TE) is an important step in characterizing and improving the cryopreservation of these systems. TEs were formed by entrapping human dermal fibroblasts (HDFs) in collagen or in fibrin gels. Freezing studies were conducted using a Linkam cryostage fitted to an optical microscope allowing observation of the TEs cooled under controlled rates between 5 and 130 degrees C/min. Typically, freezing of cellular systems results in two biophysical processes that are both dependent on the cooling rate: dehydration and/or intracellular ice formation (IIF). Both these processes can potentially be destructive to cells. In this study, the biophysics of freezing cells in collagen and fibrin TEs have been quantified and compared to freezing cells in suspension. Experimental data were fitted in numerical models to extract parameters that governed water permeability, E(Lp) and L(pg), and intracellular ice nucleation, omega(o) and kappa(o). Results indicate that major differences exist between freezing HDFs in suspension and in a tissue equivalent. During freezing, 55% of the HDFs in suspension formed IIF as compared to 100% of HDFs forming IIF in collagen and fibrin TE at a cooling rate of 130 degrees C/min. Also, both the water permeability and the IIF parameters were determined to be higher for HDFs in TEs as compared to cell suspensions. Between the TEs, HDFs in fibrin TE exhibited higher values for the biophysical parameters as compared to HDFs in collagen TE. The observed biophysics seems to indicate that cell-cell and cell-matrix interactions play a major role in ice propagation in TEs.
- Published
- 2006
- Full Text
- View/download PDF
47. Extracorporeal membrane oxygenation with lepirudin anticoagulation for Wegener's granulomatosis with heparin-induced thrombocytopenia.
- Author
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Balasubramanian SK, Tiruvoipati R, Chatterjee S, Sosnowski A, and Firmin RK
- Subjects
- Granulomatosis with Polyangiitis pathology, Heparin, Hirudins, Humans, Lung diagnostic imaging, Lung pathology, Male, Middle Aged, Radiography, Recombinant Proteins therapeutic use, Respiratory Distress Syndrome therapy, Thrombocytopenia chemically induced, Treatment Outcome, Anticoagulants therapeutic use, Extracorporeal Membrane Oxygenation methods, Granulomatosis with Polyangiitis complications, Thrombocytopenia drug therapy
- Abstract
Venovenous extracorporeal membrane oxygenation with lepirudin anticoagulation was successfully used for a complicated case of Wegener's granulomatosis and heparin-induced thrombocytopenia. Interestingly, a linear correlation was found between activated partial thromboplastin time and activated clotting time during lepirudin anticoagulation.
- Published
- 2005
- Full Text
- View/download PDF
48. Successful use of venovenous extracorporeal membrane oxygenation in accidental hypothermic cardiac arrest.
- Author
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Tiruvoipati R, Balasubramanian SK, Khoshbin E, Hadjinikolaou L, Sosnowski AW, and Firmin RK
- Subjects
- Heart Arrest etiology, Humans, Hypothermia complications, Male, Middle Aged, Rewarming methods, Treatment Outcome, Extracorporeal Membrane Oxygenation methods, Heart Arrest therapy, Hypothermia therapy
- Abstract
Cardiopulmonary bypass is usually used for rewarming and for providing cardiac support in patients with severe hypothermia and cardiovascular instability. We report the first case of accidental severe hypothermia associated with prolonged cardiac arrest that was successfully managed by venovenous extracorporeal membrane oxygenation.
- Published
- 2005
- Full Text
- View/download PDF
49. Heat and mass transfer during the cryopreservation of a bioartificial liver device: a computational model.
- Author
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Balasubramanian SK and Coger RN
- Subjects
- Computer Simulation, Humans, Models, Biological, Cryopreservation, Hot Temperature, Liver, Artificial
- Abstract
Bioartificial liver devices (BALs) have proven to be an effective bridge to transplantation for cases of acute liver failure. Enabling the long-term storage of these devices using a method such as cryopreservation will ensure their easy off the shelf availability. To date, cryopreservation of liver cells has been attempted for both single cells and sandwich cultures. This study presents the potential of using computational modeling to help develop a cryopreservation protocol for storing the three dimensional BAL: Hepatassist. The focus is upon determining the thermal and concentration profiles as the BAL is cooled from 37 degrees C-100 degrees C, and is completed in two steps: a cryoprotectant loading step and a phase change step. The results indicate that, for the loading step, mass transfer controls the duration of the protocol, whereas for the phase change step, when mass transfer is assumed negligible, the latent heat released during freezing is the control factor. The cryoprotocol that is ultimately proposed considers time, cooling rate, and the temperature gradients that the cellular space is exposed to during cooling. To our knowledge, this study is the first reported effort toward designing an effective protocol for the cryopreservation of a three-dimensional BAL device.
- Published
- 2005
- Full Text
- View/download PDF
50. Predictors of mortality in early surgical intervention for active native valve endocarditis and significance of antimicrobial therapy: a single-center experience.
- Author
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Balasubramanian SK, Behranwala A, Devbhandari M, Nzewi O, Walker WS, Prasad SU, and Mankad PS
- Subjects
- Adult, Aged, Aged, 80 and over, Bioprosthesis adverse effects, Drug Administration Schedule, Female, Heart Failure mortality, Heart Valve Prosthesis adverse effects, Heart Valves surgery, Hospital Mortality, Humans, Male, Middle Aged, Postoperative Complications mortality, Preoperative Care, Renal Insufficiency mortality, Retrospective Studies, Sepsis mortality, Survival Rate, United Kingdom epidemiology, Ventricular Dysfunction, Left mortality, Anti-Bacterial Agents therapeutic use, Endocarditis, Bacterial mortality, Endocarditis, Bacterial therapy, Heart Valves microbiology
- Abstract
Background and Aim of the Study: Cardiac surgery for active infective endocarditis remains a challenging and high-risk procedure. The outcome from early surgical intervention for active native valve endocarditis (ANVE) was studied, the aim being to identify significant predictors of mortality and the relationship between duration of preoperative antibiotics and outcome., Methods: Between January 1996 and February 2002, 61 patients with ANVE underwent surgery within four weeks of diagnosis. Preoperatively, 29 patients received antibiotics for <2 weeks (group A), and 32 received antibiotics for 2-4 weeks (group B). The median follow up period was 37.4 months (range: 21-55 months). Data were collected retrospectively and analyzed. To determine factors related to mortality, Kaplan-Meier survival analysis was employed, utilizing log-rank statistics to identify evidence of significant differences between the groups. The relationship between the duration of preoperative antibiotics and morbidity was determined using chi-square and Fisher's Exact tests, as appropriate., Results: Overall operative mortality was 14.8% (group A, 13.8%; group B, 15.6%). Rates of early and late prosthetic valve endocarditis were 1.8% and 1.9% (only in group B) respectively. The overall survival rate for the follow up period was 81.9%. Predictors of mortality were extensive infection (p = 0.01), poor left ventricular function (p <0.0001), progressive cardiac failure as an indication for surgery (p <0.0001), postoperative sepsis (p <0.0001), renal failure after surgery (p = 0.0002) and use of a bioprosthetic valve (p = 0.045). There were no significant inter-group differences for extensive infection (p = 1.00), postoperative sepsis (p = 1.00), reoperation (p = 1.00) and mortality (p = 1.00)., Conclusion: In patients with ANVE, early aggressive surgical intervention before the onset of cardiac failure and spread of infection is warranted. The present data suggest that, in these patient groups, the duration of preoperative antibiotics had no significant influence on postoperative morbidity and mortality.
- Published
- 2005
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