44 results on '"Tharakan S"'
Search Results
2. Scalable Kernel Methods for Uncertainty Quantification
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Tharakan, S., March, W. B., Biros, G., Barth, Timothy J., Series editor, Griebel, Michael, Series editor, Keyes, David E., Series editor, Nieminen, Risto M., Series editor, Roose, Dirk, Series editor, Schlick, Tamar, Series editor, Mehl, Miriam, editor, Bischoff, Manfred, editor, and Schäfer, Michael, editor
- Published
- 2015
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3. High-Density Geometric Morphometric Analysis of Intraspecific Cranial Integration in the Barred Grass Snake (Natrix helvetica) and Green Anole (Anolis carolinensis)
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Tharakan, S, primary, Shepherd, N, additional, Gower, D J, additional, Stanley, E L, additional, Felice, R N, additional, Goswami, A, additional, and Watanabe, A, additional
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- 2023
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4. An Effect of Stress Relieving on the Microstructural and Mechanical Properties of Mg-3Zn-1Cu-0.7Mn/ Al2O3 Composite Synthesized by Powder Metallurgy
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Silan Tharakan. S Silan Tharakan. S and Tjprc
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Fluid Flow and Transfer Processes ,Materials science ,Mechanical Engineering ,Powder metallurgy ,Metallurgy ,Composite number ,Stress relieving ,Aerospace Engineering - Published
- 2019
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5. Improved hardness characteristics of Mg-3Zn-1Cu-0.7Mn alloy composites reinforced with Al2O3 synthesized by powder metallurgy
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Tharakan, S Silan, primary and Sivapragash, M, additional
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- 2020
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6. Improving Gene Therapy Efficacy Using Impella
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Tharakan, S., primary, Kariya, T., additional, Yamada, K., additional, Bikou, O., additional, and Ishikawa, K., additional
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- 2020
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7. Atypical presentations of ectopic pancreatic tissue
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Sulser, P S, Azarhoush, S, Aronson, D C; https://orcid.org/0000-0001-5139-7552, Tharakan, S J, Zweifel, N, Moehrlen, Ueli; https://orcid.org/0000-0001-6418-1136, Sulser, P S, Azarhoush, S, Aronson, D C; https://orcid.org/0000-0001-5139-7552, Tharakan, S J, Zweifel, N, and Moehrlen, Ueli; https://orcid.org/0000-0001-6418-1136
- Abstract
Background Ectopic pancreatic tissue (EPT) in a Meckel diverticulum is a well-known anomaly. Other locations are rare, especially in pediatric patients. We report on three children with incidental findings of EPT and reviewed the literature. Patients and methods Three children with incidental findings of EPT treated in our department, and 62 patients found in the literature were analyzed. The literature search was performed excluding EPT in Meckel's diverticulum and in tumors, i.e. teratomas. Results Two of our patients presented with an umbilical mass. The third patient presented with a gastric outlet obstruction due to an antral/pyloric mass. Histopathology showed EPT in all three of our patients without any signs of malignancy. In the literature, patients with EPT often appear to be asymptomatic. Symptomatic patients may present with bowel obstruction or intussusception. EPT in the umbilicus frequently seems to cause umbilical discharge. Our analysis supported the leading opinion in the literature that the upper gastrointestinal tract and especially the gastric antrum must be considered the most common location of EPT. Conclusion Although unusual in children, awareness of EPT may help to obtain the proper diagnosis faster and to plan accurate surgical therapy.
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- 2020
8. Transglutaminasen als Marker epidermaler Differenzierung in einem aus menschlichen Schweissdrüsenzellen hergestellten Epidermissubstitut
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Tharakan, S J, University of Zurich, and Tharakan, S J
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UZHDISS UZH Dissertations ,610 Medicine & health ,10220 Clinic for Surgery - Published
- 2009
9. Human eccrine sweat gland cells can reconstitute a stratified epidermis
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Biedermann, T, Pontiggia, L; https://orcid.org/0000-0002-5553-8997, Böttcher-Haberzeth, S, Tharakan, S, Braziulis, E, Schiestl, C, Meuli, M, Reichmann, E, Biedermann, T, Pontiggia, L; https://orcid.org/0000-0002-5553-8997, Böttcher-Haberzeth, S, Tharakan, S, Braziulis, E, Schiestl, C, Meuli, M, and Reichmann, E
- Abstract
Eccrine sweat glands are generally considered to be a possible epidermal stem cell source. Here we compared the multilayered epithelia formed by epidermal keratinocytes and those formed by eccrine sweat gland cells. We demonstrated both in vitro and in vivo the capability of human eccrine sweat gland cells to form a stratified interfollicular epidermis substitute on collagen hydrogels. This is substantiated by the following findings: (1) a stratified epidermis consisting of 10-12 cell layers is formed by sweat gland cells; (2) a distinct stratum corneum develops and is maintained after transplantation onto immuno-incompetent rats; (3) proteins such as filaggrin, loricrin, involucrin, envoplakin, periplakin, and transglutaminases I and III match with the pattern of the normal human skin; (4) junctional complexes and hemidesmosomes are readily and regularly established; (5) cell proliferation in the basal layer reaches homeostatic levels; (6) the sweat gland-derived epidermis is anchored by hemidesmosomes within a well-developed basal lamina; and (7) palmo-plantar or mucosal markers are not expressed in the sweat gland-derived epidermis. These data suggest that human eccrine sweat glands are an additional source of keratinocytes that can generate a stratified epidermis. Our findings raise the question of the extent to which the human skin is repaired and/or permanently renewed by eccrine sweat gland cells.
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- 2010
10. Nanoparticle-Mediated Gene Delivery via Balloon Angioplasty to Suppress Intimal Hyperplasia
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DiRito, J.R., primary and Tharakan, S., additional
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- 2014
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11. Adoptive cell therapy in acute myeloid leukemia: the current landscape and emerging strategies.
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Tharakan S, Tremblay D, and Azzi J
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- Humans, Tumor Microenvironment immunology, Killer Cells, Natural immunology, Animals, Immunotherapy, Adoptive methods, Immunotherapy, Adoptive adverse effects, Leukemia, Myeloid, Acute therapy, Leukemia, Myeloid, Acute immunology, Receptors, Chimeric Antigen immunology
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Efforts to produce adoptive cell therapies in AML have been largely unfruitful, despite the success seen in lymphoid malignancies. Identifying targetable antigens on leukemic cells that are absent on normal progenitor cells remains a major obstacle, as is the hostile tumor microenvironment created by AML blasts. In this review, we summarize the challenges in the development of adoptive cell therapies such as CAR-T, CAR-NK, and TCR-T cells in AML, discussing both autologous and allogeneic therapies. We also discuss methods to address myelotoxicity associated with these therapies, including rapidly switchable CAR platforms and CRISPR-Cas9 genetic engineering of hematopoietic stem cells. Finally, we present the current clinical landscape in these areas, along with future directions in the field.
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- 2025
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12. The Clinical Application of Gel-Based Composite Scaffolds in Rotator Cuff Repair.
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Tharakan S, Hadjiargyrou M, and Ilyas A
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Rotator cuff tears are a common injury that can be treated with or without surgical intervention. Gel-based scaffolds have gained significant attention in the field of tissue engineering, particularly for applications like rotator cuff repair. Scaffolds can be biological, synthetic, or a mixture of both materials. Collagen, a primary constituent of the extracellular matrix (ECM) in musculoskeletal tissues, is one of the most widely used materials for gel-based scaffolds in rotator cuff repair, but other ECM-based and synthetic-based composite scaffolds have also been utilized. These composite scaffolds can be engineered to mimic the biomechanical and biological properties of natural tissues, supporting the healing process and promoting regeneration. Various clinical studies examined the effectiveness of these composite scaffolds with collagen, ECM and synthetic polymers and provided outstanding results with remarkable improvements in range of motion (ROM), strength, and pain. This review explores the material composition, manufacturing process and material properties of gel-based composite scaffolds as well as their clinical outcomes for the treatment of rotator cuff injuries.
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- 2024
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13. AAV delivery strategy with mechanical support for safe and efficacious cardiac gene transfer in swine.
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Mazurek R, Tharakan S, Mavropoulos SA, Singleton DT, Bikou O, Sakata T, Kariya T, Yamada K, Kohlbrenner E, Liang L, Ravichandran AJ, Watanabe S, Hajjar RJ, and Ishikawa K
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- Animals, Swine, Female, Male, Disease Models, Animal, Humans, Transduction, Genetic, Gold chemistry, Myocardium metabolism, Hemodynamics, Dependovirus genetics, Gene Transfer Techniques, Heart Failure therapy, Heart Failure genetics, Genetic Therapy methods, Genetic Vectors administration & dosage, Genetic Vectors genetics
- Abstract
Adeno-associated virus-based gene therapy is a promising avenue in heart failure treatment, but has shown limited cardiac virus uptake in humans, requiring new approaches for clinical translation. Using a Yorkshire swine ischemic heart failure model, we demonstrate significant improvement in gene uptake with temporary coronary occlusions assisted by mechanical circulatory support. We first show that mechanical support during coronary artery occlusions prevents hemodynamic deterioration (n = 5 female). Subsequent experiments show that coronary artery occlusions during gene delivery improve gene transduction, while adding coronary sinus occlusion (Stop-flow) further improves gene expression up to >1 million-fold relative to conventional intracoronary infusion. Complete survival during and after delivery (n = 10 female, n = 10 male) further indicates safety of the approach. Improved cardiac gene expression correlates with virus uptake without an increase in extra-cardiac expression. Stop-flow delivery of virus-sized gold nanoparticles exhibits enhanced endothelial adherence and uptake, suggesting a mechanism independent of virus biology. Together, utilizing mechanical support for cardiac gene delivery offers a clinically-applicable strategy for heart failure-targeted therapies., Competing Interests: Competing interests: Part of this study was supported by a research grant from Abiomed, Inc. to the institution. K.I. serves as the principal investigator on the grant from Abiomed, Inc. K.I. received an honorarium from Abiomed, Inc. and served as a consultant for Pfizer, Inc., and Gordian Biotechnology. T.S. and T.K. were supported by A-CURE Research Fellowship supported by Abiomed, Inc.. K.I. and R.J.H. have a patent, “SYSTEMS AND METHODS FOR LEFT VENTRICULAR UNLOADING IN BIOLOGIC THERAPY OR VECTORED GENE THERAPY” Publication number: 20200305888. All other authors declare no competing interests., (© 2024. The Author(s).)
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- 2024
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14. Impact of Facility Type on Survival in Chronic Myelomonocytic Leukemia: A Propensity Score Matched, National Cancer Database Analysis.
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Tharakan S, Feld J, Van Hyfte G, Mascarenhas J, and Tremblay D
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- Humans, Male, Female, Aged, Middle Aged, Aged, 80 and over, United States epidemiology, Adult, Survival Analysis, Leukemia, Myelomonocytic, Chronic mortality, Leukemia, Myelomonocytic, Chronic therapy, Propensity Score, Databases, Factual
- Abstract
Background: Chronic myelomonocytic leukemia (CMML) is a rare and likely underdiagnosed hematologic malignancy. Due to its rarity and nuances in diagnosis, many patients are referred to tertiary referral centers, although many continue to be cared for in the community setting. Given discrepancies in outcomes based on facility type in related myeloid malignancies, we hypothesized that CMML patients treated at academic centers may have improved survival as compared to patients treated at nonacademic centers (NACs)., Patients and Methods: Using the National Cancer Database (NCDB), we identified 6290 patients with CMML and collected data on demographics, comorbidities, treatment, and survival. We also performed a propensity matched analysis to control for baseline differences., Results: We found that patients at academic centers had higher median overall survival (OS) (17.7 months vs 14.7 months) and 5-year OS (19.1% vs 15.3%) than patients at NACs. In addition, patients treated at an academic center were also more likely to receive hematopoietic stem cell transplant as compared to those treated at NACs. Time to treatment initiation was overall similar between academic and NACs., Conclusion: Our study of one of the largest available datasets of CMML patients supports the importance of referring CMML patients to academic centers upon diagnosis to optimize outcomes in this rare hematologic malignancy., Competing Interests: Disclosure All authors have completed the ICMJE uniform disclosure form. J.M. receives clinical research funding paid to his institution from Incyte, Novartis, Celgene/BMS, CTI Bio, Geron, AbbVie, PharmaEssentia, Kartos, and Karyopharm. He receives consulting fees from Incyte, CTI Bio, Novartis, Geron, Kartos, Karyopharm, MorphoSys, AbbVie, Celgene/BMS, PharmaEssentia, Pfizer, Imago, Merck, Roche, GSK, Galecto. D.T. receives clinical research funding paid to his institution from Astellas Pharma, Gilead, CTI Bio and consulting fees from GSH, CTI Bio, Novartis, AbbVie, Sierra Oncology, and Cogent Biosciences. J.F. receives clinical research funding from Oryzon and Syros Pharmaceuticals. S.T. has no disclosures to report., (Copyright © 2024 Elsevier Inc. All rights reserved.)
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- 2024
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15. Capsular Repair, Labral Repair, and Femoroplasty With Postless Traction Are Increasingly Performed for the Arthroscopic Treatment of Femoroacetabular Impingement Syndrome.
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Bartlett L, Tharakan S, Klein B, Trasolini RG, Sgaglione NA, and Cohn RM
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- Humans, Male, Retrospective Studies, Female, Adult, Middle Aged, Joint Capsule surgery, Hip Joint surgery, Treatment Outcome, Young Adult, Femoracetabular Impingement surgery, Arthroscopy methods, Traction methods
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Purpose: To provide an updated assessment of hip arthroscopy use by using an institutional database that is specific to the treatment of femoroacetabular impingement syndrome (FAIS)., Methods: All patients undergoing hip arthroscopy for the treatment of FAIS were retrospectively identified between the years 2014 and 2022 via Current Procedural Terminology coding in a multi-institutional, single health system database. A longitudinal analysis was performed to identify trends in the use of arthroscopic techniques including capsular and labral treatment, osteoplasty, and traction set-up., Results: During the study, 789 arthroscopic hip procedures in 733 patients were analyzed (56 staged bilateral). Between 2016 and 2022, the number of hip arthroscopies performed each year increased by 1,490% (R
2 = 0.87, P = .001). Capsular repair (R2 = 0.92, P < .001), labral repair (R2 = 0.75, P = .002), and femoroplasty (R2 = 0.70, P = .004) were performed in an increasing proportion of cases over our study period whereas labral debridement (R2 = -0.84, P < .001) became less used. Postless traction systems were employed in 84% (663/789) of hip arthroscopies overall, were used in at least 70% of hip arthroscopies each year, and did not undergo any significant changes in use (R2 = 0.02, P = .73)., Conclusions: Capsular repair, labral repair, and femoroplasty were increasingly performed for the arthroscopic treatment of FAIS whereas the use of labral debridement decreased significantly over our study period. Postless traction systems were used in the majority of cases each year., Clinical Relevance: As comparative literature continues to define the safety and efficacy of hip arthroscopy, understanding how novel techniques or procedures are incorporated in clinical practice is important., Competing Interests: Disclosure All authors (L.B., S.T., B.K., R.G.T., N.A.S., R.M.C.) declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. Full ICMJE author disclosure forms are available for this article online, as supplementary material., (Copyright © 2024 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.)- Published
- 2024
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16. Do ChatGPT and Google differ in answers to commonly asked patient questions regarding total shoulder and total elbow arthroplasty?
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Tharakan S, Klein B, Bartlett L, Atlas A, Parada SA, and Cohn RM
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- Humans, Artificial Intelligence, Internet, Search Engine, Arthroplasty, Replacement, Elbow methods, Arthroplasty, Replacement, Shoulder, Patient Education as Topic methods
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Background: Artificial intelligence (AI) and large language models (LLMs) offer a new potential resource for patient education. The answers by Chat Generative Pre-Trained Transformer (ChatGPT), a LLM AI text bot, to frequently asked questions (FAQs) were compared to answers provided by a contemporary Google search to determine the reliability of information provided by these sources for patient education in upper extremity arthroplasty., Methods: "Total shoulder arthroplasty" (TSA) and "total elbow arthroplasty" (TEA) were entered into Google Search and ChatGPT 3.0 to determine the ten most FAQs. On Google, the FAQs were obtained through the "people also ask" section, while ChatGPT was asked to provide the ten most FAQs. Each question, answer, and reference(s) cited were recorded. A modified version of the Rothwell system was used to categorize questions into 10 subtopics: special activities, timeline of recovery, restrictions, technical details, cost, indications/management, risks and complications, pain, longevity, and evaluation of surgery. Each reference was categorized into the following groups: commercial, academic, medical practice, single surgeon personal, or social media. Questions for TSA and TEA were combined for analysis and compared between Google and ChatGPT with a 2 sample Z-test for proportions., Results: Overall, most questions were related to procedural indications or management (17.5%). There were no significant differences between Google and ChatGPT between question categories. The majority of references were from academic websites (65%). ChatGPT produced a greater number of academic references compared to Google (80% vs. 50%; P = .047), while Google more commonly provided medical practice references (25% vs. 0%; P = .017)., Conclusion: In conjunction with patient-physician discussions, AI LLMs may provide a reliable resource for patients. By providing information based on academic references, these tools have the potential to improve health literacy and improved shared decision making for patients searching for information about TSA and TEA., Clinical Significance: With the rising prevalence of AI programs, it is essential to understand how these applications affect patient education in medicine., (Copyright © 2024 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)
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- 2024
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17. Comparative antioxidant analysis of extracts prepared from Indigofera longiracemosa aerial parts identifies leaf methanolic extract as a promising antioxidant.
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Chankaramkandath Vasu A, Tharakan S, and Kadunganattil S
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Extraction of phytochemicals from the leaves and stems of Indigofera longiracemosa , a previously underexplored dye-yielding plant, was done using four solvents of increasing polarity followed by in vitro assessment of their antioxidant potential. Of the four solvent extracts, methanol extract yielded the highest percentage of phytochemicals. Methanol extracts of leaves and stems also showed the best antioxidant potential in in vitro antioxidant assays. Further, comparison with known standard antioxidant molecules showed lower IC
50 values for the extracts tested. Our study thereby validates for the first time the antioxidant potential of I. longiracemosa aerial parts, and identifies an extract enriched in phytochemicals capable of quenching free radicals in vitro at concentrations lower than or comparable to pure antioxidant molecules.- Published
- 2024
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18. Understanding triple negative myeloproliferative neoplasms: pathogenesis, clinical features, and management.
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Tharakan S, Mascarenhas J, and Tremblay D
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- Humans, Mutation, Janus Kinase 2 genetics, Calreticulin genetics, Myeloproliferative Disorders genetics, Primary Myelofibrosis genetics, Thrombocythemia, Essential genetics, Neoplasms
- Abstract
ABSTRACT Myeloproliferative neoplasms (MPNs) that lack the classical "driver mutations," termed triple negative MPNs, remain a poorly understood entity. Despite considerable progress toward understanding MPN pathobiology, the mechanisms leading to the development of these MPNs remains inadequately elucidated. While triple negative primary myelofibrosis (TN-PMF) portends a poor prognosis, triple negative essential thrombocythemia (TN-ET) is more favorable as compared with JAK2 mutated ET. In this review, we summarize the clinical features and prognosis of TN-PMF and -ET as well as diagnostic challenges including identification of non-canonical driver mutations. We also discuss additional molecular drivers to better understand possible pathogenic mechanisms underlying triple negative MPNs. Finally, we highlight current therapeutic approaches as well as novel targets, particularly in the difficult to treat TN-PMF population.
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- 2024
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19. Body temperature as a predictor of mortality in COVID-19.
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Uchiyama S, Sakata T, Tharakan S, and Ishikawa K
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- Body Temperature, Humans, Male, Female, Adult, Middle Aged, Aged, Aged, 80 and over, COVID-19 mortality
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It remains uncertain if body temperature (BT) is a useful prognostic indicator in coronavirus disease 2019 (COVID-19). We investigated the relationship between BT and mortality in COVID-19 patients. We used a de-identified database that prospectively collected information from patients screened for COVID-19 at the Mount Sinai facilities from February 28, 2020 to July 28, 2021. All patients diagnosed with COVID-19 that had BT data were included. BT at initial presentation, maximum BT during hospitalization, comorbidity, and vaccination status data were extracted. Mortality rate was assessed as a primary outcome. Among 24,293 cases, patients with initial BT below 36 °C had higher mortality than those with BT of 36-37 °C (p < 0.001, odds ratio 2.82). Initial BT > 38 °C was associated with high mortality with an incremental trend at higher BT. In 10,503 in-patient cases, a positive association was observed between mortality and maximum BT except in patients with BT < 36 °C. Multiple logistic regression analyses including the comorbidities revealed that maximum BT was an independent predictor of mortality. While vaccination did not change the distribution of maximum BT, mortality was decreased in vaccinated patients. Our retrospective cohort study suggests that high maximum BT is an independent predictor of higher mortality in COVID-19 patients., (© 2023. Springer Nature Limited.)
- Published
- 2023
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20. T1 Gastric Cancer Is Associated With a High Incidence of Regional Lymph Node Metastases.
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Imtiaz S, Berger Y, Gleeson E, Williams HS, Durham DM, Mahajan D, Buseck A, Tharakan S, Zheng S, Macfie R, Labow D, Cohen NA, Golas BJ, Sarpel U, and Hiotis SP
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- Humans, Male, Female, Neoplasm Staging, Lymphatic Metastasis pathology, Incidence, Lymph Node Excision, Lymph Nodes diagnostic imaging, Lymph Nodes surgery, Lymph Nodes pathology, Retrospective Studies, Stomach Neoplasms pathology
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Introduction: Early stage gastric cancer, particularly T1 disease, is associated with high recurrence-free and overall survival rates following resection with curative intent. However, rare cases of T1 gastric cancer have nodal metastasis and this is associated with poor outcomes., Methods: Data from gastric cancer patients treated with surgical resection and D2 lymph node (LN) dissection at a single tertiary care institution from 2010 to 2020 were analyzed. Patients with early stage (T1) tumors were assessed in detail to identify variables associated with regional LN metastasis including histologic differentiation, signet ring cells, demographics, smoking history, neoadjuvant therapy, and clinical staging by endoscopic ultrasound (EUS). We used standard statistical techniques including Mann-Whitney U and Chi-squared tests., Results: Of 426 patients undergoing surgery for gastric cancer, 34% (n = 146) were diagnosed with T1 disease on surgical pathology. Among 146 T1 (T1a, T1b) gastric cancers, 24 patients [(17%) T1a (n = 4), T1b (n = 20)] had histologically confirmed regional LN metastases. The age at diagnosis ranged between 19 and 91 y and 54.8% were male. Prior smoking status was not associated with nodal positivity (P = 0.650). Of the 24 patients with positive LN on final pathology, seven patients received neoadjuvant chemotherapy. EUS was performed on 98 (67%) of the 146 T1 patients. Of these patients, 12 (13.2%) had positive LN on final pathology; however, none (0/12) were detected on preoperative EUS. There was no association between node status on EUS and node status on final pathology (P = 0.113). The sensitivity of EUS for N status was 0%, specificity was 84.4%, negative predictive value was 82.2% and positive predictive value was 0%. Signet ring cells were identified in 42% of node negative T1 tumors and 64% of node positive T1 tumors (P = 0.063). For LN positive cases on surgical pathology, 37.5% had poor differentiation, 42% had lymphovascular invasion, and regional nodal metastases were associated with increasing T stage (P = 0.003)., Conclusions: T1 gastric cancer is associated with a substantial risk (17%) of regional LN metastasis, when pathologically staged following surgical resection and D2 lymphadenectomy. Clinically staged N+ disease by EUS was not significantly associated with pathologically staged N+ disease in these patients., (Copyright © 2022. Published by Elsevier Inc.)
- Published
- 2023
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21. The Use of Hydrogels for the Treatment of Bone Osteosarcoma via Localized Drug-Delivery and Tissue Regeneration: A Narrative Review.
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Tharakan S, Raja I, Pietraru A, Sarecha E, Gresita A, Petcu E, Ilyas A, and Hadjiargyrou M
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Osteosarcoma is a malignant tumor of bone that leads to poor mortality and morbidity. Management of this cancer through conventional methods involves invasive treatment options that place patients at an increased risk of adverse events. The use of hydrogels to target osteosarcoma has shown promising results both in vitro and in vivo to eradicate tumor cells while promoting bone regeneration. The loading of hydrogels with chemotherapeutic drugs provides a route for site-specific targeted therapy for osteosarcoma. Current studies demonstrate tumor regression in vivo and lysis of tumor cells in vitro when exposed to doped hydrogel scaffolds. Additionally, novel stimuli-responsive hydrogels are able to react with the tissue microenvironment to facilitate the controlled release of anti-tumor drugs and with biomechanical properties that can be modulated. This narrative review of the current literature discusses both in vitro and in vivo studies of different hydrogels, including stimuli-responsive, designed to treat bone osteosarcoma. Future applications to address patient treatment for this bone cancer are also discussed.
- Published
- 2023
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22. 3D Printed Osteoblast-Alginate/Collagen Hydrogels Promote Survival, Proliferation and Mineralization at Low Doses of Strontium Calcium Polyphosphate.
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Tharakan S, Khondkar S, Lee S, Ahn S, Mathew C, Gresita A, Hadjiargyrou M, and Ilyas A
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The generation of biomaterials via 3D printing is an emerging biotechnology with novel methods that seeks to enhance bone regeneration. Alginate and collagen are two commonly used biomaterials for bone tissue engineering and have demonstrated biocompatibility. Strontium (Sr) and Calcium phosphate (CaP) are vital elements of bone and their incorporation in composite materials has shown promising results for skeletal repair. In this study, we investigated strontium calcium polyphosphate (SCPP) doped 3D printed alginate/collagen hydrogels loaded with MC3T3-E1 osteoblasts. These cell-laden scaffolds were crosslinked with different concentrations of 1% SCPP to evaluate the effect of strontium ions on cell behavior and the biomaterial properties of the scaffolds. Through scanning electron microscopy and Raman spectroscopy, we showed that the scaffolds had a granular surface topography with the banding pattern of alginate around 1100 cm
-1 and of collagen around 1430 cm-1 . Our results revealed that 2 mg/mL of SCPP induced the greatest scaffold degradation after 7 days and least amount of swelling after 24 h. Exposure of osteoblasts to SCPP induced severe cytotoxic effects after 1 mg/mL. pH analysis demonstrated acidity in the presence of SCPP at a pH between 2 and 4 at 0.1, 0.3, 0.5, and 1 mg/mL, which can be buffered with cell culture medium. However, when the SCPP was added to the scaffolds, the overall pH increased indicating intrinsic activity of the scaffold to buffer the SCPP. Moreover, cell viability was observed for up to 21 days in scaffolds with early mineralization at 0.3, 0.5, and 1 mg/mL of SCPP. Overall, low doses of SCPP proved to be a potential additive in biomaterial approaches for bone tissue engineering; however, the cytotoxic effects due to its pH must be monitored closely.- Published
- 2022
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23. Microfluidic Devices for HIV Diagnosis and Monitoring at Point-of-Care (POC) Settings.
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Tharakan S, Faqah O, Asghar W, and Ilyas A
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- Humans, Point-of-Care Systems, Point-of-Care Testing, Flow Cytometry, Lab-On-A-Chip Devices, HIV Infections diagnosis
- Abstract
Human immunodeficiency virus (HIV) is a global epidemic; however, many individuals are able to obtain treatment and manage their condition. Progression to acquired immunodeficiency syndrome (AIDS) occurs during late-stage HIV infection, which compromises the immune system, making it susceptible to infections. While there is no cure, antiretroviral therapy can be used provided that detection occurs, preferably during the early phase. However, the detection of HIV is expensive and resource-intensive when tested with conventional methods, such as flow cytometry, polymerase chain reaction (PCR), or enzyme-linked immunosorbent assays (ELISA). Improving disease detection in resource-constrained areas requires equipment that is affordable, portable, and can deliver rapid results. Microfluidic devices have transformed many benchtop techniques to on-chip detection for portable and rapid point-of-care (POC) testing. These devices are cost-effective, sensitive, and rapid and can be used in areas lacking resources. Moreover, their functionality can rival their benchtop counterparts, making them efficient for disease detection. In this review, we discuss the limitations of currently used conventional HIV diagnostic assays and provide an overview of potential microfluidic technologies that can improve HIV testing in POC settings.
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- 2022
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24. Controlled Biodegradation and Swelling of Strontium-doped Alginate/Collagen Scaffolds for Bone Tissue Engineering.
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Khondkar S, Tharakan S, Badran A, Hadjiargyrou M, and Ilyas A
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- Alginates, Calcium Phosphates metabolism, Collagen, Osteoblasts metabolism, Polyphosphates metabolism, Strontium metabolism, Tissue Engineering
- Abstract
Treatment for critical size defects (CSDs) in bone often use bone grafts to act as a scaffold to help complete healing. Biological scaffolds require bone extraction from the individual or an outside donor while synthetic grafts mostly suffer from poor degradation kinetics and decreased bioactivity. In this study, we investigated a 3D printed scaffold derived from a novel composite bioink composed of alginate and collagen augmented with varying doses from 2 m g/ m L to 20 m g/ m L of 1% strontium-calcium polyphosphate (SCPP) to control biodegradability and fluid uptake. Scaffolds with increased SCPP concentrations showed higher particle density, lesser swelling ratio and greater biodegradability indicating that these critically important properties for bone healing are fine-tunable and highly dependent on SCPP dosing. Clinical Relevance- The dosing of 1% SCPP into porous alginate/collagen scaffolds provides adjustable long-term degradation and material properties suitable for potential in vivo CSD applications.
- Published
- 2022
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25. Endobronchial Aerosolized AAV1.SERCA2a Gene Therapy in a Pulmonary Hypertension Pig Model: Addressing the Lung Delivery Bottleneck.
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Bikou O, Tharakan S, Yamada KP, Kariya T, Aguero J, Gordon A, Mazurek R, Aikawa T, Kohlbrenner E, Fish KM, Hajjar RJ, and Ishikawa K
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- Animals, Dependovirus genetics, Dependovirus metabolism, Gene Transfer Techniques, Genetic Therapy methods, Genetic Vectors genetics, Lung metabolism, Sarcoplasmic Reticulum Calcium-Transporting ATPases genetics, Sarcoplasmic Reticulum Calcium-Transporting ATPases therapeutic use, Swine, Hypertension, Pulmonary drug therapy, Hypertension, Pulmonary therapy
- Abstract
A disappointing number of new therapies for pulmonary hypertension (PH) have been successfully translated to the clinic. Adeno-associated viral (AAV) gene therapy has the potential to treat the underlying pathology of PH, but the challenge remains in efficient and safe delivery. The aims of this study were (1) to test the efficacy of endobronchial aerosolization delivery for AAV1-mediated sarcoplasmic/endoplasmic reticulum Ca
2+ ATPase 2a ( SERCA2a ) gene therapy in a PH pig model and (2) to identify the most efficient airway administration modality for in-lung gene therapy in PH. We hypothesized that delivery to the distal bronchi increases lung viral uptake and avoids virus loss in off-target compartments. In part 1 of the study, PH was induced in pigs by surgically banding the pulmonary veins. Two months postsurgery, 1 × 1013 viral genomes (vg) of AAV1. SERCA2a or saline was endobronchially aerosolized using a bronchoscope. Two months after aerosolization, high vg copies (vgc) were detected in the lungs, accompanied by functional and morphometrical amelioration of PH. In part 2 of the study, we directly compared the endobronchial aerosolization gene delivery to the intratracheal aerosolization in PH pigs. Endobronchial delivery demonstrated higher viral expression (6,719 ± 927 vs. 1,444 ± 402 vgc/100 ng DNA, p = 0.0017), suggesting this delivery modality is a promising method for clinical AAV gene therapy for PH.- Published
- 2022
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26. Cholinergic Signaling Attenuates Pro-Inflammatory Interleukin-8 Response in Colonic Epithelial Cells.
- Author
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Müller I, Kym U, Galati V, Tharakan S, Subotic U, Krebs T, Stathopoulos E, Schmittenbecher P, Cholewa D, Romero P, Reingruber B, Holland-Cunz S, and Keck S
- Subjects
- Cell Line, Female, Humans, Infant, Male, Colon innervation, Colon metabolism, Enteric Nervous System metabolism, Epithelial Cells metabolism, Hirschsprung Disease metabolism, Interleukin-8 metabolism
- Abstract
Infants affected by Hirschsprung disease (HSCR), a neurodevelopmental congenital disorder, lack ganglia of the intrinsic enteric nervous system (aganglionosis) in a variable length of the colon, and are prone to developing severe Hirschsprung-associated enterocolitis (HAEC). HSCR patients typically show abnormal dense innervation of extrinsic cholinergic nerve fibers throughout the aganglionic rectosigmoid. Cholinergic signaling has been reported to reduce inflammatory response. Consequently, a sparse extrinsic cholinergic innervation in the mucosa of the rectosigmoid correlates with increased inflammatory immune cell frequencies and higher incidence of HAEC in HSCR patients. However, whether cholinergic signals influence the pro-inflammatory immune response of intestinal epithelial cells (IEC) is unknown. Here, we analyzed colonic IEC isolated from 43 HSCR patients with either a low or high mucosal cholinergic innervation density (fiber-low versus fiber-high) as well as from control tissue. Compared to fiber-high samples, IEC purified from fiber-low rectosigmoid expressed significantly higher levels of IL-8 but not TNF-α, IL-10, TGF-β1, Muc-2 or tight junction proteins. IEC from fiber-low rectosigmoid showed higher IL-8 protein concentrations in cell lysates as well as prominent IL-8 immunoreactivity compared to IEC from fiber-high tissue. Using the human colonic IEC cell line SW480 we demonstrated that cholinergic signals suppress lipopolysaccharide-induced IL-8 secretion via the alpha 7 nicotinic acetylcholine receptor (a7nAChR). In conclusion, we showed for the first time that the presence of a dense mucosal cholinergic innervation is associated with decreased secretion of IEC-derived pro-inflammatory IL-8 in the rectosigmoid of HSCR patients likely dependent on a7nAChR activation. Owing to the association between IL-8 and enterocolitis-prone, fiber-low HSCR patients, targeted therapies against IL-8 might be a promising immunotherapy candidate for HAEC treatment., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Müller, Kym, Galati, Tharakan, Subotic, Krebs, Stathopoulos, Schmittenbecher, Cholewa, Romero, Reingruber, NIGStudy Group, Holland-Cunz and Keck.)
- Published
- 2022
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27. Bioprinting of Stem Cells in Multimaterial Scaffolds and Their Applications in Bone Tissue Engineering.
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Tharakan S, Khondkar S, and Ilyas A
- Subjects
- Osteogenesis, Printing, Three-Dimensional, Tissue Engineering, Tissue Scaffolds, Bioprinting, Mesenchymal Stem Cells
- Abstract
Bioprinting stem cells into three-dimensional (3D) scaffolds has emerged as a new avenue for regenerative medicine, bone tissue engineering, and biosensor manufacturing in recent years. Mesenchymal stem cells, such as adipose-derived and bone-marrow-derived stem cells, are capable of multipotent differentiation in a 3D culture. The use of different printing methods results in varying effects on the bioprinted stem cells with the appearance of no general adverse effects. Specifically, extrusion, inkjet, and laser-assisted bioprinting are three methods that impact stem cell viability, proliferation, and differentiation potential. Each printing method confers advantages and disadvantages that directly influence cellular behavior. Additionally, the acquisition of 3D bioprinters has become more prominent with innovative technology and affordability. With accessible technology, custom 3D bioprinters with capabilities to print high-performance bioinks are used for biosensor fabrication. Such 3D printed biosensors are used to control conductivity and electrical transmission in physiological environments. Once printed, the scaffolds containing the aforementioned stem cells have a significant impact on cellular behavior and differentiation. Natural polymer hydrogels and natural composites can impact osteogenic differentiation with some inducing chondrogenesis. Further studies have shown enhanced osteogenesis using cell-laden scaffolds in vivo. Furthermore, selective use of biomaterials can directly influence cell fate and the quantity of osteogenesis. This review evaluates the impact of extrusion, inkjet, and laser-assisted bioprinting on adipose-derived and bone-marrow-derived stem cells along with the effect of incorporating these stem cells into natural and composite biomaterials.
- Published
- 2021
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28. Pan-cancer proteogenomic investigations identify post-transcriptional kinase targets.
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Elmas A, Tharakan S, Jaladanki S, Galsky MD, Liu T, and Huang KL
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- Adult, Aged, Algorithms, Child, Female, Humans, Male, Middle Aged, Neoplasms physiopathology, Phosphorylation, Protein Kinases metabolism, Signal Transduction, Gene Expression Regulation, Neoplastic, Neoplasms genetics, Protein Kinases genetics, Proteogenomics methods, Up-Regulation
- Abstract
Identifying genomic alterations of cancer proteins has guided the development of targeted therapies, but proteomic analyses are required to validate and reveal new treatment opportunities. Herein, we develop a new algorithm, OPPTI, to discover overexpressed kinase proteins across 10 cancer types using global mass spectrometry proteomics data of 1,071 cases. OPPTI outperforms existing methods by leveraging multiple co-expressed markers to identify targets overexpressed in a subset of tumors. OPPTI-identified overexpression of ERBB2 and EGFR proteins correlates with genomic amplifications, while CDK4/6, PDK1, and MET protein overexpression frequently occur without corresponding DNA- and RNA-level alterations. Analyzing CRISPR screen data, we confirm expression-driven dependencies of multiple currently-druggable and new target kinases whose expressions are validated by immunochemistry. Identified kinases are further associated with up-regulated phosphorylation levels of corresponding signaling pathways. Collectively, our results reveal protein-level aberrations-sometimes not observed by genomics-represent cancer vulnerabilities that may be targeted in precision oncology., (© 2021. The Author(s).)
- Published
- 2021
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29. The impact of the globalization of cancer clinical trials on the enrollment of Black patients.
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Tharakan S, Zhong X, and Galsky MD
- Subjects
- Black People, Humans, Internationality, United States epidemiology, United States Food and Drug Administration, Black or African American, Drug Approval, Neoplasms drug therapy
- Abstract
Background: The enrollment of Black patients in cancer clinical trials continues to trend far below the true prevalence of disease in Black patients in the United States, limiting the generalizability of trial results. A potentially overlooked contributor to the underenrollment of Black patients may be the increasing enrollment of cancer trials in countries outside the United States. However, the impact of the globalization of cancer clinical trials on recruitment of racial minority patients has been understudied., Methods: In this study, race and accrual location data for all cancer drugs approved by the US Food and Drug Administration (FDA) between 2015 and 2018 were analyzed. A disparity score was calculated for each approval, a metric comparing Black enrollment in clinical trials with the estimated burden of disease in Black patients., Results: Of 49 global clinical trials supporting 35 FDA drug approvals with race data available, Black patients accounted for 2.5% of enrollment (range, 0%-10%), with a median disparity score of 0.19 (range, 0.01-0.98). In 21 clinical trials supporting 18 FDA drug approvals with both race and accrual location data available, 64% patients were enrolled outside the United States (range, 0%-100%). Black patients accounted for 3.2% of enrollment (range, 0.2%-10%), and the median disparity score was 0.23 (range, 0.01-0.98). There was a significant inverse correlation between the proportion of trial patients enrolled outside the United States and the disparity score (Pearson correlation, -0.61; P = .007)., Conclusions: The globalization of cancer clinical trials is associated with a widening racial enrollment disparity gap in the United States. The impact of global trials on domestic clinical trial generalizability warrants further consideration from a regulatory and policy standpoint., Lay Summary: Black patients continue to be underrepresented in cancer clinical trials; this disparity has worsened in recent years perhaps because of the globalization of cancer clinical trials. In an analysis of demographic information from 21 cancer clinical trials leading to US Food and Drug Administration approvals between 2015 and 2018, clinical trials conducted primarily outside the United States were 2-fold less likely to enroll Black participants than US clinical trials. Thus, the globalization of cancer clinical trials may have the unintended consequence of further exacerbating existing racial disparities in cancer clinical trial representation and ultimately the generalizability of trial results., (© 2021 American Cancer Society.)
- Published
- 2021
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30. Left Ventricular Assist Devices for Acute Myocardial Infarct Size Reduction: Meta-analysis.
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Miyashita S, Kariya T, Yamada KP, Bikou O, Tharakan S, Kapur NK, and Ishikawa K
- Subjects
- Animals, Disease Models, Animal, Myocardial Infarction pathology, Myocardial Infarction physiopathology, Prosthesis Design, Prosthesis Implantation adverse effects, Heart-Assist Devices, Myocardial Infarction therapy, Myocardium pathology, Prosthesis Implantation instrumentation, Ventricular Function, Left
- Abstract
We conducted a meta-analysis of preclinical studies that tested left ventricular assist device (LVAD) therapy for reducing myocardial infarct size in experimental acute myocardial infarction (AMI). Twenty-six articles were included with a total of 488 experimental animal subjects. The meta-analysis showed that infarct size was significantly decreased by LVAD support compared to control animals (SDM, - 2.19; 95% CI, - 2.70 to - 1.69; P < 0.001). The meta-regression analysis demonstrated a high degree of heterogeneity associated with time from coronary artery occlusion to LVAD support, which correlated positively with infarct size. Subgroup analysis suggested smaller infarct size in LVAD therapies that withdrew blood from left heart than those from right heart. The proportion of left ventricular support relative to total cardiac output was positively correlated with infarct size reduction in Impella studies. Thus, early initiation of LVAD after ischemia and effective left ventricular venting may be important factors to reduce infarct size in AMI.
- Published
- 2021
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31. Corrigendum: Novel Porcine Model of Coronary Dissection Reveals the Impact of Impella on Dissected Coronary Arterial Hemodynamics.
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Kariya T, Yamada KP, Bikou O, Tharakan S, Miyashita S, and Ishikawa K
- Abstract
[This corrects the article DOI: 10.3389/fcvm.2020.00162.]., (Copyright © 2021 Kariya, Yamada, Bikou, Tharakan, Miyashita and Ishikawa.)
- Published
- 2021
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32. Fetal surgery for spina bifida in Zurich: results from 150 cases.
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Moehrlen U, Ochsenbein N, Vonzun L, Mazzone L, Horst M, Schauer S, Wille DA, Hagmann C, Kottke R, Grehten P, Casanova B, Strübing N, Moehrlen T, Tharakan S, Padden B, Bassler D, Zimmermann R, and Meuli M
- Subjects
- Adult, Child, Female, Gestational Age, Humans, Hydrocephalus surgery, Infant, Newborn, Meningomyelocele surgery, Pregnancy, Spinal Dysraphism complications, Switzerland, Treatment Outcome, Fetus surgery, Spinal Dysraphism surgery
- Abstract
Purpose: Over the past 10 years, over 150 fetal spina bifida surgeries were performed at the Zurich Center for Fetal Diagnosis and Therapy. This study looks at surrogates for success and failure of this approach., Methods: We focused on key outcome parameters including hydrocephalus shunt rate at one year, bladder control at 4, independent ambulation at 3 years, and maternal, fetal, and neonatal complications., Results: From the first 150 patients undergoing fetal surgery for spina bifida, 148 (98.7%) were included in the study. Maternal-fetal surgery was uneventful in 143/148 (97%) cases. Intraoperative problems included resuscitation in 4/148 fetuses (2.7%). 1/148 fetuses (0.7%) died on postoperative day 4. Maternal complications included chorioamniotic membrane separation in 22/148 (15%), lung embolism in 3/148 (2.1%), chorioamnionitis in 2/148 (1.4%), AV-block III and uterine rupture in 1/148 each (0.7%). 1/148 (0.7%) newborn death was recorded. Hindbrain herniation was identified preoperatively in 132/148 (90%) fetuses and resolved completely in 119/132 (90%). At one year, 39/106 (37%) children had required a CSF diversion. At 4 years, 4/34 patients (12%) had normal bladder control. At 3 years, 48/57 (84%) walked independently., Conclusion: A majority of patients benefitted from prenatal intervention, in that the shunt rate was lower and the rates of continent and walking patients were higher than reported with postnatal care.
- Published
- 2021
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33. Secondary Invasive Breast Events among Patients with Hormone-Positive Breast Cancer and High-Risk Oncotype DX Recurrence Scores 26-30 and ≥31.
- Author
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Berger NF, Zimmerman BS, Tharakan S, Suchman K, Cascetta KP, Blanter J, Moshier E, Ru M, Jaffer S, and Tiersten A
- Subjects
- Adult, Aged, Aged, 80 and over, Breast Neoplasms drug therapy, Chemotherapy, Adjuvant methods, Female, Follow-Up Studies, Humans, Kaplan-Meier Estimate, Middle Aged, Neoplasm Recurrence, Local drug therapy, Prognosis, Retrospective Studies, Risk Factors, Treatment Outcome, Breast Neoplasms genetics, Breast Neoplasms metabolism, Gene Expression Profiling methods, Neoplasm Recurrence, Local genetics, Neoplasm Recurrence, Local metabolism, Receptors, Estrogen metabolism, Transcriptome
- Abstract
Background: The Oncotype DX Recurrence Score (ODx RS) is the most widely adopted genomic assay used to guide treatment for patients with early-stage, hormone-positive (HR+) breast cancer (BC), with higher scores predicting greater risk of recurrence and benefit from chemotherapy. Patients with ODx RS >25 typically recieve adjuvant chemotherapy; however, data regarding efficacy of chemotherapy for reducing recurrence in this population have been mixed., Objectives: This study aimed to evaluate outcomes of patients with early-stage HR+ BC with high-risk ODx RS (26-30 and ≥31) in order to assess treatment patterns and outcomes. We hypothesized that the benefit of chemotherapy in these groups may be minimal and that select patients may forgo chemotherapy in favor of more aggressive endocrine therapy and ovarian suppression., Methods: We performed a retrospective analysis of 515 patients with early-stage, HR+ BC with high-risk ODx RS 26-30 and ≥31 treated between 2006 and 2018. Patients were stratified by RS: low-risk (≤10), intermediate-risk (11-25), and high-risk (≥26). The Kaplan-Meier method was used to estimate the time to secondary invasive breast events (SIBE) or distributions overall and among different RS groups with the log rank test used to compare distributions between groups., Results: Rates of chemotherapy administration were 7% among the low-risk group, 18% among the intermediate-risk group, and 83% among high-risk patients with 41 SIBE (8%) reported. When stratified by ODx RS, 5-year rates of SIBE were 4%, 6%, and 16% for low-risk, intermediate-risk, and high-risk RS, respectively. Among the 27 lymph node (LN)-negative patients with ODx RS 26-30, 74% received chemotherapy. The 5-year rate of SIBE was 25% among patients who received chemotherapy and 33% among those who did not (p = 0.5489). Among the 23 LN-negative patients with ODx RS ≥31, 91% of patients received chemotherapy. The 5-year rate of SIBE was 0% both with and without chemotherapy., Conclusions: There was no statistically significant difference in SIBE for patients with high-risk ODx RS based on chemotherapy treatment. More aggressive endocrine therapy with ovarian suppression has become an alternative to chemotherapy among patients with intermediate-risk ODx RS (16-25). This approach may be useful among patients with high-risk ODx RS, with additional studies needed in this patient population., (© 2021 S. Karger AG, Basel.)
- Published
- 2021
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34. Impaired left ventricular global longitudinal strain is associated with elevated left ventricular filling pressure after myocardial infarction.
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Aikawa T, Kariya T, Yamada KP, Miyashita S, Bikou O, Tharakan S, Fish K, and Ishikawa K
- Subjects
- Animals, Disease Models, Animal, Female, Male, Myocardial Infarction physiopathology, Predictive Value of Tests, Sus scrofa, Echocardiography, Three-Dimensional, Myocardial Infarction diagnostic imaging, Stroke Volume, Ventricular Function, Left, Ventricular Pressure
- Abstract
Left ventricular (LV) global longitudinal strain (GLS) has emerged as a significant prognostic marker in patients after myocardial infarction (MI). Although elevated LV filling pressure after MI might alter GLS, direct evidence for this is lacking. This study aimed to clarify the association between GLS and LV filling pressure in a large animal MI model. A total of 104 Yorkshire pigs underwent both echocardiographic and hemodynamic assessments 1-4 wk after induction of large anterior MI. GLS was measured in the apical four-chamber view using a semiautomated speckle-tracking software. LV pressure-volume relationship was invasively measured using a high-fidelity pressure-volume catheter. GLS >-14% was considered impaired. Compared with pigs with LV ejection fraction (LVEF) >40% and preserved GLS ( n = 29), those with LVEF >40% and impaired GLS ( n = 37) and those with LVEF ≤40% ( n = 38) had significantly higher LV end-diastolic pressure (15.5 ± 5.5 vs. 19.7 ± 5.8 and 19.6 ± 6.6 mmHg; P = 0.008 and P = 0.026, respectively) and higher LV mean diastolic pressure (7.1 ± 2.9 vs. 10.4 ± 4.5 and 11.1 ± 5.4 mmHg; P = 0.013 and P = 0.002, respectively). GLS was modestly correlated with τ ( r = 0.21, P = 0.039) and slope of LV end-diastolic pressure-volume relationship ( r = 0.43, P < 0.001). Impaired GLS was associated with higher LV end-diastolic and mean-diastolic pressures after adjusting for LVEF and baseline characteristics ( P = 0.026 and P = 0.001, respectively). Impaired GLS assessed by speckle-tracking echocardiography was associated with elevated LV filling pressure after MI. GLS has an incremental diagnostic value for detecting elevated LV filling pressure and may be particularly useful for evaluating post-MI patients with preserved LVEF. NEW & NOTEWORTHY Strain analysis was performed in 104 pigs after MI, and its relationship to invasive hemodynamic measurements was studied. Impaired longitudinal strain was associated with high ventricular filling pressure independent of LVEF in post-MI setting. Global longitudinal strain is a potential prognostic marker after MI.
- Published
- 2020
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35. Novel Porcine Model of Coronary Dissection Reveals the Impact of Impella on Dissected Coronary Arterial Hemodynamics.
- Author
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Kariya T, Yamada KP, Bikou O, Tharakan S, Miyashita S, and Ishikawa K
- Abstract
Background: Coronary artery dissection (CAD) sometimes accompanies unstable hemodynamics and requires mechanical cardiac support. Meanwhile, mechanical cardiac support may influence coronary hemodynamics in CAD. No study has examined the impact of Impella left ventricular (LV) support on CAD. Materials and Methods: CAD was induced in eight Yorkshire pigs by injuring the left anterior descending artery (LAD) using a 0.018-in. stiff guidewire and/or deep engagement of a blunt-cut coronary guiding catheter. After the creation of CAD, hemodynamic parameters, coronary pressure, and flow as well as coronary angiograms were acquired before and after maximum LV support using the Impella CP. Result: CADs with a large flap were successfully created by deep engagement of a blunt-tip guiding catheter with forceful contrast injection. One animal (#8) exhibited thrombolysis in myocardial infarction (TIMI)-1 flow, while the others (animals #1-#7) showed TIMI-2/3 flow. In TIMI-2/3 animals, maximal Impella support increased mean coronary pressure (108.4 ± 22.5 to 124.7 ± 28.0 mmHg, P < 0.001) with unchanged mean coronary flow velocity (63.50 ± 28.66 to 48.32 ± 13.30 cm/s, P = 0.17) of the LAD distal to the dissection. The LV end-diastolic pressure (20.6 ± 6.6 vs. 12.0 ± 3.4 mmHg, P = 0.032), LV end-diastolic volume (127 ± 32 vs. 97 ± 26 ml, P = 0.015), stroke volume (68 ± 16 vs. 48 ± 14 ml, P = 0.003), stroke work (5,744 ± 1,866 vs. 4,424 ± 1,650 mmHg·ml, P = 0.003), and heart rate (71.4 ± 6.6 vs. 64.9 ± 9.3/min, P = 0.014) were all significantly reduced by Impella support, indicating effective unloading of the LV. In the TIMI-1 animal (animal #8), maximal Impella support resulted in further delay in angiographic coronary flow and reduced distal coronary pressure (22.9-17.1 mmHg), together with increased false-lumen pressure. Conclusion: Impella support effectively unloaded the LV and maintained the hemodynamics in a novel porcine model of CAD. Coronary pressure distal to the dissection was increased in TIMI-2/3 animals after Impella support but decreased in the animal with initial TIMI-1 flow., (Copyright © 2020 Kariya, Yamada, Bikou, Tharakan, Miyashita and Ishikawa.)
- Published
- 2020
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36. Body temperature correlates with mortality in COVID-19 patients.
- Author
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Tharakan S, Nomoto K, Miyashita S, and Ishikawa K
- Subjects
- Adult, Aged, Aged, 80 and over, COVID-19, Coronavirus Infections therapy, Female, Humans, Male, Middle Aged, Pandemics, Pneumonia, Viral therapy, Body Temperature, Coronavirus Infections mortality, Pneumonia, Viral mortality
- Published
- 2020
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37. Consideration of clinical translation of cardiac AAV gene therapy.
- Author
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Yamada KP, Tharakan S, and Ishikawa K
- Abstract
Advancements in conventional cardiac care have significantly reduced mortality from coronary heart disease and acute myocardial infarction. However, the prevalence of heart failure continues to increase in an aging population with profound social and economic consequences. Cardiac gene therapy with adeno-associated virus (AAV) vectors is emerging as a potential modality for addressing this desperate clinical need. After showing initial promise in extensive preclinical studies and an early clinical trial, disappointing results of large-scale clinical trial derailed the progress of AAV-mediated cardiac gene therapy. However, it appears that knowledge gained from previous failures coupled with developments in targeted gene delivery have set the stage for a new frontier in cardiac AAV gene therapy.
- Published
- 2020
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38. Diabetes and Metformin Association with Recurrence Score in a Large Oncotype Database of Breast Cancer Patients.
- Author
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Tharakan S, Zimmerman B, Ru M, Blanter J, Cascetta K, and Tiersten A
- Subjects
- Adolescent, Adult, Aged, Comorbidity, Databases, Factual, Disease-Free Survival, Female, Humans, Middle Aged, Receptor, ErbB-2 metabolism, Retrospective Studies, Young Adult, Breast Neoplasms epidemiology, Diabetes Mellitus, Type 2 drug therapy, Diabetes Mellitus, Type 2 epidemiology, Hypoglycemic Agents therapeutic use, Metformin therapeutic use, Neoplasm Recurrence, Local epidemiology
- Abstract
Background: The Oncotype DX® (ODX) is a genomic assay that provides clinicians with a prediction of benefit of chemotherapy in node-negative, tamoxifen-treated breast cancer. However, the relationship between ODX recurrence score (RS) and diabetes, a common comorbidity in breast cancer patients, has been inadequately described in the literature. Specifically, the association of diabetes treatment with metformin and RS is inconclusive, with different studies reporting conflicting results. Because diabetes has been associated with higher RS, it has been suggested that management of diabetes with metformin in breast cancer patients may be associated with a lower RS., Objectives: We studied a large cohort of early-stage, hormone-positive breast cancer patients to determine if there is an association between RS and metformin treatment., Methods: In this study, we retrospectively examined the medical records of 514 early-stage, hormone-positive breast cancer patients who had oncotype testing performed between 2007 and 2017. Number (%) or median were used to describe the patients' characteristics between groups and were compared by the Kruskal-Wallis test at a significance level of 5%., Results: Of this cohort, 67 (13%) had a diabetes diagnosis at the time of breast cancer diagnosis, including both diabetes mellitus and pre-diabetes. The median RS for non-diabetic patients was 16 and the median RS for diabetic patients was 15. This difference was not significant, nor was there a statistical difference in RS between diabetic patients taking metformin (median RS = 15) and diabetic patients not taking metformin (median RS = 15). These results held true even when controlling for BMI., Conclusions: We conclude that neither diabetes diagnosis nor metformin use is associated with a difference in oncotype RS in this population of diabetic patients., (© 2020 S. Karger AG, Basel.)
- Published
- 2020
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39. BRCA Mutation Association with Recurrence Score and Discordance in a Large Oncotype Database.
- Author
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Blanter J, Zimmerman B, Tharakan S, Ru M, Cascetta K, and Tiersten A
- Subjects
- Breast Neoplasms pathology, Databases, Factual, Female, Humans, Breast Neoplasms epidemiology, Breast Neoplasms genetics, Genes, BRCA1, Genes, BRCA2, Mutation, Neoplasm Recurrence, Local epidemiology
- Abstract
Background: The Oncotype DX Breast Cancer Assay is a 21-gene assay used to predict the likelihood of distant recurrence and the benefit of chemotherapy in patients with node-negative, tamoxifen-treated breast cancer. Prior studies demonstrated 7-19% discordance, or a difference between the recurrence score (RS) and tumor grade (TG) in breast cancer patients. BRCA mutated tumors (BRCA+) have been shown to be associated with higher RS as compared to BRCA-negative patients (BRCA-)., Objectives: We developed a large Oncotype RS database to determine if the BRCA mutation status is associated with discordance., Methods: We identified 723 patients (32 [4%] mutation-positive and 691 [96%] mutation-negative patients) with early-stage, hormone-positive breast cancer treated between 2006 and 2018, with tumor characteristics available for analysis. Discordance was defined as one- or two-step difference between RS (low, intermediate, high risk) and TG (well [WD], moderately [MD], and poorly [PD] differentiated). Mutation positive was defined as BRCA1 deleterious mutation, BRCA2 deleterious mutation, BRCA mutation of unknown type, BRCA variant of undetermined significance (VUS) or other mutation (classified as other VUS). Number (%) or median were used to describe patient characteristics between groups and were compared by the Kruskal-Wallis test at a significance level of 5%., Results: Among these patients, there were 32 (4% of total) who were identified as mutation-positive. Of those patients, 16% had a documented deleterious mutation in BRCA1, 22% in BRCA2, 6% had a BRCA mutation of unknown type (either 1 or 2), 25% were BRCA VUS, and 31% other VUS (most commonly CHEK2 and ATM). The median RS was 23.5 in patients with deleterious BRCA mutations (1, 2 or unknown) versus 16 in patients in the BRCA-negative database, which was statistically significant (p < 0.01). One- and two-step discordance was present in 46 and 8%, respectively, of patients with deleterious BRCA mutations versus 53 and 11%, respectively, in the BRCA-negative database., Conclusions: Patients with deleterious BRCA mutations demonstrated no difference in rates of discordance as compared to BRCA-negative patients. We further demonstrated that patients with BRCA-positive tumors display higher RS than patients with BRCA-negative tumors., (© 2020 S. Karger AG, Basel.)
- Published
- 2020
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40. A Novel Large Animal Model of Thrombogenic Coronary Microembolization.
- Author
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Bikou O, Tharakan S, Yamada KP, Kariya T, Gordon A, Miyashita S, Watanabe S, Sassi Y, Fish K, and Ishikawa K
- Abstract
Coronary microembolization is one of the main causes of the "no-reflow" phenomenon, which commonly occurs after reperfusion of an occluded coronary artery. Given its high incidence and the fact that it has been proven to be an independent predictor of cardiac morbidity and mortality, there is an imperative need to study its underlying mechanisms and pathophysiology. Large animal models are essential to perform translational studies. Currently there is no animal model that recapitulates a clinical scenario of thrombogenic microembolism with preceding myocardial ischemia. Therefore, the goal of this study was to develop and characterize a novel pig model of coronary microembolization using autologous thrombus injection (CMET). Twenty-three pigs underwent myocardial infarction through percutaneous balloon occlusion of the left anterior descending artery (LAD). Each animal was enrolled in one of two groups: (1) the CMET group, in which the LAD occlusion was followed by delivery of autologous clotted blood in the LAD (distal to the balloon occlusion) and reperfusion; (2) the ischemic reperfusion (I/R) group, in which the LAD ischemia was followed by reperfusion. Surviving animals underwent functional and morphological characterization at 1-week post-procedure. Three sham operated animals were used as a control. CMET resulted in impaired left ventricular function compared to I/R pigs at 1 week. Three-dimensional echocardiography demonstrated reduced ejection fraction in the CMET group (CMET vs. I/R: 35.6 ± 4.2% vs. 47.6 ± 2.4%, p = 0.028). Invasive hemodynamic measurements by Swan-Ganz and left ventricular pressure-volume catheters revealed that CMET impaired left ventricular contractility and diastolic function. This was confirmed by both load-dependent indices including cardiac output (CMET vs. I/R: 2.7 ± 0.2 l/min, vs. 4.0 ± 0.1 l/min, p = 0.002) and load independent indices including preload-recruitable stroke work (CMET vs. I/R: 25.8 ± 4.0 vs. 47.5 ± 6.5 mmHg, p = 0.05) and end-diastolic pressure-volume relationship (slope, 0.68 ± 0.07 vs. 0.40 ± 0.11 mmHg/ml, p = 0.01). Our unique closed-chest model of coronary microembolization using autologous thrombus injection resembles the clinical condition of thrombogenic coronary microembolization in I/R injury. This model offers opportunities to conduct translational studies for understanding and treating coronary microembolization in myocardial infarction., (Copyright © 2019 Bikou, Tharakan, Yamada, Kariya, Gordon, Miyashita, Watanabe, Sassi, Fish and Ishikawa.)
- Published
- 2019
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41. Prenatal and Postnatal Management of Gastroschisis in German-Speaking Countries: Is There a Standardized Management?
- Author
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Schib K, Schumacher M, Meuli M, Tharakan S, and Subotic U
- Subjects
- Austria, Cryptorchidism complications, Cryptorchidism surgery, Delivery, Obstetric statistics & numerical data, Female, Fetal Therapies, Gastroschisis complications, Gastroschisis diagnosis, Germany, Gestational Age, Humans, Infant, Newborn, Intestinal Atresia complications, Male, Postoperative Care, Practice Guidelines as Topic, Pregnancy, Prenatal Diagnosis, Surveys and Questionnaires, Switzerland, Gastroschisis surgery, Intestinal Atresia surgery, Intestines surgery
- Abstract
Introduction: Evidence-based guidelines or protocols regarding the perinatal management of babies born with gastroschisis are lacking. The aim of this work is to evaluate the different current treatment modalities for newborns with gastroschisis during the perinatal period in the German-speaking countries Germany, Austria, and Switzerland. These data could serve as a starting point for the development of a multicenter randomized controlled trial., Materials and Methods: A questionnaire was developed with 30 questions divided into five sections: (1) prenatal diagnosis, (2) fetal therapy, (3) mode and timing of delivery, (4) operative management, and (5) postoperative management. All pediatric surgery institutions that treat newborns with gastroschisis were identified and asked to participate. Data were categorized by country and analyzed using descriptive statistics (frequency and percentage)., Results: The return rate of the questionnaire was 95% (89 hospitals). A standard procedure was identified regarding prenatal ultrasound monitoring, interdisciplinary team approach, planned delivery through cesarean section, postnatal coverage of the intestine with a silastic bag, first intervention within the first 6 hours after birth, attempt of primary abdominal wall closure, and perioperative antibiotic treatment. For many crucial parameters, management was not standardized., Conclusions: There is no gold standard in German-speaking countries on how to manage fetuses and babies with gastroschisis. Moreover, this report unveils some questionable elements of daily practice for which there is no evidence at all and which can jeopardize outcome and even prove fatal (fetal therapy, preterm delivery, lack of abdominal pressure monitoring). Prospective randomized-controlled multicenter studies are needed to set a standard., Competing Interests: None., (Georg Thieme Verlag KG Stuttgart · New York.)
- Published
- 2018
- Full Text
- View/download PDF
42. Fetal surgery in Zurich: key features of our first open in utero repair of myelomeningocele.
- Author
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Meuli M, Moehrlen U, Flake A, Ochsenbein N, Huesler M, Biro P, Scheer I, Tharakan S, Dürig P, and Zimmermann R
- Subjects
- Clinical Protocols, Female, Humans, Magnetic Resonance Imaging methods, Pregnancy, Treatment Outcome, Fetal Therapies methods, Fetus surgery, Meningomyelocele surgery
- Published
- 2013
- Full Text
- View/download PDF
43. Human eccrine sweat gland cells can reconstitute a stratified epidermis.
- Author
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Biedermann T, Pontiggia L, Böttcher-Haberzeth S, Tharakan S, Braziulis E, Schiestl C, Meuli M, and Reichmann E
- Subjects
- Adolescent, Animals, Biomarkers metabolism, Cells, Cultured, Child, Child, Preschool, Desmosomes physiology, Epidermis physiology, Epidermis ultrastructure, Fibroblasts cytology, Fibroblasts metabolism, Fibroblasts ultrastructure, Filaggrin Proteins, Homeostasis physiology, Humans, Immunocompetence, Infant, Keratinocytes cytology, Keratinocytes metabolism, Keratinocytes ultrastructure, Mice, Microscopy, Electron, Transmission, Organ Culture Techniques, Rats, Stem Cells metabolism, Stem Cells ultrastructure, Sweat Glands physiology, Sweat Glands ultrastructure, Swiss 3T3 Cells cytology, Epidermal Cells, Skin Transplantation, Stem Cells cytology, Sweat Glands cytology, Tissue Engineering methods, Transplantation, Heterologous
- Abstract
Eccrine sweat glands are generally considered to be a possible epidermal stem cell source. Here we compared the multilayered epithelia formed by epidermal keratinocytes and those formed by eccrine sweat gland cells. We demonstrated both in vitro and in vivo the capability of human eccrine sweat gland cells to form a stratified interfollicular epidermis substitute on collagen hydrogels. This is substantiated by the following findings: (1) a stratified epidermis consisting of 10-12 cell layers is formed by sweat gland cells; (2) a distinct stratum corneum develops and is maintained after transplantation onto immuno-incompetent rats; (3) proteins such as filaggrin, loricrin, involucrin, envoplakin, periplakin, and transglutaminases I and III match with the pattern of the normal human skin; (4) junctional complexes and hemidesmosomes are readily and regularly established; (5) cell proliferation in the basal layer reaches homeostatic levels; (6) the sweat gland-derived epidermis is anchored by hemidesmosomes within a well-developed basal lamina; and (7) palmo-plantar or mucosal markers are not expressed in the sweat gland-derived epidermis. These data suggest that human eccrine sweat glands are an additional source of keratinocytes that can generate a stratified epidermis. Our findings raise the question of the extent to which the human skin is repaired and/or permanently renewed by eccrine sweat gland cells.
- Published
- 2010
- Full Text
- View/download PDF
44. Transglutaminases, involucrin, and loricrin as markers of epidermal differentiation in skin substitutes derived from human sweat gland cells.
- Author
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Tharakan S, Pontiggia L, Biedermann T, Böttcher-Haberzeth S, Schiestl C, Reichmann E, and Meuli M
- Subjects
- Adolescent, Animals, Biomarkers metabolism, Cell Differentiation physiology, Cells, Cultured, Child, Child, Preschool, Disease Models, Animal, Epidermis metabolism, Epidermis transplantation, Female, Fluoroimmunoassay, Humans, Infant, Keratinocytes cytology, Mice, Rats, Rats, Nude, Sweat Glands metabolism, Wound Healing, Wounds and Injuries metabolism, Wounds and Injuries therapy, Epidermal Cells, Keratinocytes metabolism, Membrane Proteins metabolism, Protein Precursors metabolism, Skin, Artificial, Sweat Glands cytology, Transglutaminases metabolism
- Abstract
Background/purpose: In a multi-project research line, we are currently testing whether a morphologically and functionally near normal epidermis can be cultured from human sweat gland (SG) cells and be used as a skin substitute. The present study focuses on the stratum corneum of the epidermis that assumes a vital barrier function for the skin. The main process in the formation of the cornified cell envelope in human epidermis, i.e. crosslinking of proteins and lipids, is catalyzed by several transglutaminases (TG). Therefore, we compared the expression patterns of various TG and their substrates in SG-derived versus keratinocyte-derived epidermal substitutes., Methods: Sweat gland cells, keratinocytes, and fibroblasts were isolated from human skin samples and cultivated separately to generate epidermal substitutes. These were transplanted onto the back of athymic rats. After 2 weeks, the transplants were excised and analyzed histologically as well as by indirect immunofluorescence. We looked at the expression of TG1, 3, 5, and their substrates involucrin and loricrin (=markers of epidermal differentiation) in SG-derived and keratinocyte-derived skin substitutes as well as in normal skin., Results: The SG cell-derived epidermis was near normal anatomically, formed a cornified cell envelope and demonstrated TG1, 3, and 5 as well as involucrin and loricrin expression patterns similar to those found in keratinocyte-derived epidermis and normal control skin., Conclusion: These findings support the thesis that SG cells have the potential to form a near normal stratified epidermal analog that might be used as a skin substitute. The expression of TG1 and 3, not normally expressed in human SG, suggests the presence of re-programmed SG cells and/or stem cells capable of both de novo generating and maintaining an epidermis.
- Published
- 2010
- Full Text
- View/download PDF
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