31 results on '"Kumbar S"'
Search Results
2. Stem Cells Proliferation and Growth Factor Delivery in a New Tissue-Engineered Injectable Scaffold Designed for Dental Pulp Tissue Regeneration: OR 28
- Author
-
Yang, M., Toti, U., Tencza, L., Harmon, M., Moss, I., Laurencin, C., and Kumbar, S.
- Published
- 2012
3. Collagen nanofibril self-assembly on a natural polymeric material for the osteoinduction of stem cells in vitro and biocompatibility in vivo
- Author
-
Aravamudhan, A., primary, Ramos, D. M., additional, Jenkins, N. A., additional, Dyment, N. A., additional, Sanders, M. M., additional, Rowe, D. W., additional, and Kumbar, S. G., additional
- Published
- 2016
- Full Text
- View/download PDF
4. Tendon tissue engineering: adipose-derived stem cell and GDF-5 mediated regeneration using electrospun matrix systems
- Author
-
James, R, primary, Kumbar, S G, additional, Laurencin, C T, additional, Balian, G, additional, and Chhabra, A B, additional
- Published
- 2011
- Full Text
- View/download PDF
5. Electrospun nanofiber scaffolds: engineering soft tissues
- Author
-
Kumbar, S G, primary, James, R, additional, Nukavarapu, S P, additional, and Laurencin, C T, additional
- Published
- 2008
- Full Text
- View/download PDF
6. Chapter 7: Drug-releasing textiles.
- Author
-
Toti, U. S., Kumbar, S. G., Laurencin, C. T., Mathew, R., and Balasubramaniam, D.
- Published
- 2011
7. An assessment of solubility profiles of structurally similar hazardous pesticide in water + methanol mixture and co-solvent effect on partition coefficient
- Author
-
Kumbar, S, primary
- Published
- 2002
- Full Text
- View/download PDF
8. Crosslinked chitosan microspheres for encapsulation of diclofenac sodium: effect of crosslinking agent
- Author
-
Kumbar, S. G., primary, Kulkarni, A. R., additional, and Aminabhavi, T. M., additional
- Published
- 2002
- Full Text
- View/download PDF
9. Stimulus-Responsive “Smart” Hydrogels as Novel Drug Delivery Systems
- Author
-
Soppimath, K. S., primary, Aminabhavi, T. M., additional, Dave, A. M., additional, Kumbar, S. G., additional, and Rudzinski, W. E., additional
- Published
- 2002
- Full Text
- View/download PDF
10. Hydrogels as controlled release devices in agriculture
- Author
-
Rudzinski, W. E., primary, Dave, A. M., additional, Vaishnav, U. H., additional, Kumbar, S. G., additional, Kulkarni, A. R., additional, and Aminabhavi, T. M., additional
- Published
- 2002
- Full Text
- View/download PDF
11. Novel mechanically competent polysaccharide scaffolds for bone tissue engineering.
- Author
-
Kumbar, S G, Toti, U S, Deng, M, James, R, Laurencin, C T, Aravamudhan, A, Harmon, M, and Ramos, D M
- Published
- 2011
- Full Text
- View/download PDF
12. Electrospun polymeric nanofiber scaffolds for tissue regeneration
- Author
-
Syam Nukavarapu, Kumbar, S. G., Merrell, J. G., and Laurencin, C. T.
13. Changing pattern of user expectations regarding the library catalogue as an information retrieval tool: a case study of Mangalore University.
- Author
-
Kumbar, S. S. and Mallaiah, T. Y.
- Subjects
- *
ACADEMIC libraries , *ONLINE library catalogs , *ELECTRONIC information resources , *LIBRARY resources ,MANGALORE University (Karnataka, India) - Abstract
Describes the efforts of Mangalore University Library in developing an Online Public Access Catalogue with the aim of increasing the information retrieval efficiency and providing easy access to the users. The changing pattern of user expectations about the catalogue has also been examined. In the survey conducted prior to the introduction of on-line public access catalogue, usefulness of the library catalogue, frequency of use, users approaches, user opinions about the adequacy of bibliographical details, sources of guidance in the use of catalogue and need for user education programmes have been assessed. Based on the findings, the steps initiated for updating the card catalogue have been described. Results indicate the necessity for the joint effort of library professionals and software development experts to find out solutions to meet the user expectations effectively. It was suggested that cataloguing of all the e-resources such as CD-ROMs, DVDs available in the library was the immediate need. [ABSTRACT FROM AUTHOR]
- Published
- 2008
14. Altered lymphocyte profiles and herpes zoster infections in patients with multiple sclerosis on natalizumab.
- Author
-
Balshi A, Manning N, Dempsey J, Kumbar S, Baber U, and Sloane JA
- Subjects
- Humans, Female, Male, Adult, Middle Aged, CD4-CD8 Ratio, Natalizumab adverse effects, Natalizumab therapeutic use, Herpes Zoster immunology, Immunologic Factors adverse effects, Multiple Sclerosis, Relapsing-Remitting drug therapy, Multiple Sclerosis, Relapsing-Remitting immunology
- Abstract
Cases of herpes zoster (HZ) in patients with MS on natalizumab (NTZ) have been documented. In this study, we assessed lymphocyte subsets in NTZ-treated patients with HZ compared to matched controls without HZ. Twenty unvaccinated patients developed HZ while on NTZ for an incidence rate of 12.3 per 1000 patient-years. These patients had lower CD8+% and higher CD4+:CD8+ ratios ( p ⩽ 0.01) than non-HZ matched controls. Two patients with relapsing-remitting MS developed HZ twice while on NTZ. These findings underscore the importance of pre-NTZ HZ vaccination due to potential HZ risk., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: J.A.S. has grant funding from the National MS Society and has consulted for Biogen, Genentech, Teva, Banner, Sanofi, and Cellgene. The remaining authors have no conflicts to declare.
- Published
- 2024
- Full Text
- View/download PDF
15. The Comparison of Anxiety Tactile Using the RMS Tactile Scan in Visually Impaired Children After Performing Oral Prophylaxis by Explaining to Them the Procedure by Verbal Tactile Method.
- Author
-
Kumbar S, Rathod SA, Patil AT, Gunda S, Patil K, and Singh DM
- Abstract
Background: Dental anxiety assessment for blind children is important. Appropriate knowledge of the patient's anxiety will help to review management options specific to every child., Aim: The aim of this study was to evaluate the anxiety level using the Raghavendra, Madhuri, Sujata (RMS) tactile scale (RMS-TS) of visually impaired children after explaining the oral prophylaxis procedure verbally and by the verbal-tactile method followed by performing the oral prophylaxis procedure., Materials and Methods: A total of 30 children aged between 6 and 13 years were included in this study from a residential school for visually impaired children. These children were divided into two equal groups. One group was explained oral prophylaxis by verbal method and another was explained in a verbal-tactile method, preintervention and postintervention anxiety of the children was checked on the RMS-TS., Results: A comparison of mean values between the two groups was done using a t -test. Comparison of mean values in each group for before and after values were done using paired t -test and was found that anxiety had reduced in the verbal-tactile group more significantly than that of the verbal group., Conclusion: The study shows that the combination of verbal and tactile models for explaining the dental procedure is an effective way to reduce anxiety in blind children., How to Cite This Article: Kumbar S, Rathod SA, Patil AT, et al. The Comparison of Anxiety Tactile Using the RMS Tactile Scan in Visually Impaired Children After Performing Oral Prophylaxis by Explaining to Them the Procedure by Verbal Tactile Method. Int J Clin Pediatr Dent 2023;16(4):551-554., Competing Interests: Source of support: Nil Conflict of interest: None Patient consent statement: The author(s) have obtained written informed consent from the patient's parents/legal guardians for publication of the case report details and related images., (Copyright © 2023; The Author(s).)
- Published
- 2023
- Full Text
- View/download PDF
16. Tinospora Cordifolia (Giloy)-Induced Liver Injury During the COVID-19 Pandemic-Multicenter Nationwide Study From India.
- Author
-
Kulkarni AV, Hanchanale P, Prakash V, Kalal C, Sharma M, Kumar K, Bishnu S, Kulkarni AV, Anand L, Patwa AK, Kumbar S, Kainth S, and Philips CA
- Subjects
- Female, Humans, Male, Pandemics, Retrospective Studies, COVID-19 epidemiology, Chemical and Drug Induced Liver Injury, Chronic, Hepatitis, Tinospora
- Abstract
Tinospora cordifolia (Giloy) is an herbal supplement commonly used in the Indian alternative medicine system Ayurveda. This herb has been promoted to the public in India as an immune booster to prevent novel coronavirus disease 2019. However, small reports have recently shown an association between Giloy use and the development of herb-induced liver injury (HILI) with autoimmune features in some patients. This large retrospective Indian multicenter study spanning 13 centers at nine locations was designed to identify features and outcomes of HILI temporally associated with Giloy use. Chemical and toxicological analyses of retrieved Giloy samples using state-of-the-art methods were also performed. We report 43 patients, of whom more than half were female, with a median time from initial Giloy consumption to symptom onset of 46 days. Patients presented with acute hepatitis, acute worsening of chronic liver disease (CLD, the most common clinical presentation), or acute liver failure. Causality assessment revealed probable liver injury in 67.4%. The most common autoantibody detected was anti-nuclear antibody. Liver biopsy in a subset revealed HILI associated with autoimmune features and hepatocyte and canalicular cholestasis and neutrophilic and eosinophilic infiltration. Conclusion: Giloy is associated with acute hepatitis with autoimmune features and can unmask autoimmune hepatitis (AIH) in people with silent AIH-related CLD. Further studies on the safety (and efficacy) of untested but heavily promoted herbals in alternative systems of medicine are an unmet need in the interests of public health and are especially important during this global health emergency., (© 2022 The Authors. Hepatology Communications published by Wiley Periodicals LLC on behalf of American Association for the Study of Liver Diseases.)
- Published
- 2022
- Full Text
- View/download PDF
17. The role of gut microbiota in clinical complications, disease severity, and treatment response in severe alcoholic hepatitis.
- Author
-
Philips CA, Augustine P, Ganesan K, Ranade S, Chopra V, Patil K, Shende S, Ahamed R, Kumbar S, Rajesh S, George T, Mohanan M, Mohan N, Phadke N, Rani M, Narayanan A, and Jagan SM
- Subjects
- Granulocyte Colony-Stimulating Factor therapeutic use, Humans, Male, Severity of Illness Index, Acute Kidney Injury, End Stage Liver Disease, Gastrointestinal Microbiome, Hepatitis, Alcoholic microbiology
- Abstract
Background: Dysbiotic gut bacteria engage in the development and progression of severe alcoholic hepatitis (SAH). We aimed to characterize bacterial communities associated with clinical events (CE), identify significant bacteria linked to CE, and define bacterial relationships associated with specific CE and outcomes at baseline and after treatment in SAH., Methods: We performed 16-s rRNA sequencing on stool samples (n=38) collected at admission and the last follow-up within 90 days in SAH patients (n=26; 12 corticosteroids; 14 granulocyte colony-stimulating factor, [G-CSF]). Validated pipelines were used to plot bacterial communities, profile functional metabolism, and identify significant taxa and functional metabolites. Conet/NetworkX® was utilized to identify significant non-random patterns of bacterial co-presence and mutual exclusion for clinical events., Results: All the patients were males with median discriminant function (DF) 64, Child-Turcotte-Pugh (CTP) 12, and model for end-stage liver disease (MELD) score 25.5. At admission, 27%, 42%, and 58% had acute kidney injury (AKI), hepatic encephalopathy (HE), and infections respectively; 38.5% died at end of follow-up. Specific bacterial families were associated with HE, sepsis, disease severity, and death. Lachnobacterium and Catenibacterium were associated with HE, and Pediococcus with death after steroid treatment. Change from Enterococcus (promotes AH) to Barnesiella (inhibits E. faecium) was significant after G-CSF. Phenylpropanoid-biosynthesis (innate-immunity) and glycerophospholipid-metabolism (cellular-integrity) pathways in those without infections and the death, respectively, were upregulated. Mutual interactions between Enterococcus cecorum, Acinetobacter schindleri, and Mitsuokella correlated with admission AKI., Conclusions: Specific gut microbiota, their interactions, and metabolites are associated with complications of SAH and treatment outcomes. Microbiota-based precision medicine as adjuvant treatment may be a new therapeutic area., (© 2021. Indian Society of Gastroenterology.)
- Published
- 2022
- Full Text
- View/download PDF
18. Transjugular intrahepatic portosystemic shunt in cirrhosis: An exhaustive critical update.
- Author
-
Rajesh S, George T, Philips CA, Ahamed R, Kumbar S, Mohan N, Mohanan M, and Augustine P
- Subjects
- Ascites, Gastrointestinal Hemorrhage etiology, Gastrointestinal Hemorrhage surgery, Humans, Liver Cirrhosis complications, Liver Cirrhosis surgery, Treatment Outcome, Esophageal and Gastric Varices etiology, Esophageal and Gastric Varices surgery, Portasystemic Shunt, Transjugular Intrahepatic adverse effects
- Abstract
More than five decades after it was originally conceptualized as rescue therapy for patients with intractable variceal bleeding, the transjugular intrahepatic portosystemic shunt (TIPS) procedure continues to remain a focus of intense clinical and biomedical research. By the impressive reduction in portal pressure achieved by this intervention, coupled with its minimally invasive nature, TIPS has gained increasing acceptance in the treatment of complications of portal hypertension. The early years of TIPS were plagued by poor long-term patency of the stents and increased incidence of hepatic encephalopathy. Moreover, the diversion of portal flow after placement of TIPS often resulted in derangement of hepatic functions, which was occasionally severe. While the incidence of shunt dysfunction has markedly reduced with the advent of covered stents, hepatic encephalopathy and instances of early liver failure continue to remain a significant issue after TIPS. It has emerged over the years that careful selection of patients and diligent post-procedural care is of paramount importance to optimize the outcome after TIPS. The past twenty years have seen multiple studies redefining the role of TIPS in the management of variceal bleeding and refractory ascites while exploring its application in other complications of cirrhosis like hepatic hydrothorax, portal hypertensive gastropathy, ectopic varices, hepatorenal and hepatopulmonary syndromes, non-tumoral portal vein thrombosis and chylous ascites. It has also been utilized to good effect before extrahepatic abdominal surgery to reduce perioperative morbidity and mortality. The current article aims to review the updated literature on the status of TIPS in the management of patients with liver cirrhosis., Competing Interests: Conflict-of-interest statement: None to declare., (©The Author(s) 2020. Published by Baishideng Publishing Group Inc. All rights reserved.)
- Published
- 2020
- Full Text
- View/download PDF
19. One disease, many faces-typical and atypical presentations of SARS-CoV-2 infection-related COVID-19 disease.
- Author
-
Philips CA, Mohan N, Ahamed R, Kumbar S, Rajesh S, George T, Mohanan M, and Augustine P
- Abstract
Since the appearance of the novel coronavirus (severe acute respiratory syndrome-coronavirus-2) and related coronavirus disease 2019 (COVID-19) in China in December 2019, a very high number of small and large patient series have been published in literature from around the world. Even though the classical presentation of COVID-19 is one with respiratory symptoms with or without pneumonia that can be self-limiting or evolve into severe respiratory distress syndrome with multiple organ failure, and secondary bacterial sepsis, a large body of evidence suggests a plethora of other types of clinical presentation. In this exhaustive review, we reviewed all of the published literature on COVID-19 to identify different types of clinical presentations affecting various organ systems, to provide an in-depth analysis that may prove useful for clinicians and health-workers on the frontline, battling the severe pandemic., Competing Interests: Conflict-of-interest statement: Authors declare no conflict of interests for this article., (©The Author(s) 2020. Published by Baishideng Publishing Group Inc. All rights reserved.)
- Published
- 2020
- Full Text
- View/download PDF
20. Managing Acute Portal Hypertensive Gastropathy Bleed During the Time of COVID-19 Pandemic: Novelty or Necessity?
- Author
-
Philips CA, Kumbar S, Ahamed R, and Augustine P
- Abstract
Acute bleeding from portal hypertensive gastropathy (PHG) is an extremely rare event in the natural history of cirrhosis. The treatment recommendations include portal pressure reduction strategies including pharmacotherapy with vasoactive agents and beta-blockers and interventional strategies such as transjugular intrahepatic portosystemic shunt placement. In this report, we present the case of a patient with cirrhosis in whom acute PHG-related bleed was managed with endoscopic band ligation, a therapeutic modality which has not been described in current literature. Our decision to re-purpose a technique for variceal bleeding stems from the fact that during the ongoing COVID-19 pandemic, the technical assistance, resource availability, and sourcing of materials that were required for us to follow recommended management guidelines for acute PHG-related bleed was severely affected due to imposed lockdown between districts and states., Competing Interests: The authors have declared that no competing interests exist., (Copyright © 2020, Philips et al.)
- Published
- 2020
- Full Text
- View/download PDF
21. Modulating the Intestinal Microbiota: Therapeutic Opportunities in Liver Disease.
- Author
-
Philips CA, Augustine P, Yerol PK, Ramesh GN, Ahamed R, Rajesh S, George T, and Kumbar S
- Abstract
Gut microbiota has been demonstrated to have a significant impact on the initiation, progression and development of complications associated with multiple liver diseases. Notably, nonalcoholic fatty liver diseases, including nonalcoholic steatohepatitis and cirrhosis, severe alcoholic hepatitis, primary sclerosing cholangitis and hepatic encephalopathy, have strong links to dysbiosis - or a pathobiological change in the microbiota. In this review, we provide clear and concise discussions on the human gut microbiota, methods of identifying gut microbiota and its functionality, liver diseases that are affected by the gut microbiota, including novel associations under research, and provide current evidence on the modulation of gut microbiota and its effects on specific liver disease conditions., Competing Interests: CAP receives advisory fees and research grant support from Cipla® and Samarth Lifesciences®. The other authors have no conflict of interests related to this publication., (© 2019 Authors.)
- Published
- 2020
- Full Text
- View/download PDF
22. Acute exacerbated severe form of nonalcoholic steatohepatitis leading to acute-on-chronic liver failure: A case series.
- Author
-
Philips CA, Augustine P, Ahamed R, Rajesh S, George T, Kumbar S, Padsalgi G, and Mahadevan P
- Subjects
- Humans, Acute-On-Chronic Liver Failure etiology, Disease Progression, Non-alcoholic Fatty Liver Disease complications
- Abstract
We present three patients with uncontrolled metabolic syndrome and acute-on-chronic liver failure in whom, after meticulous evaluation, the acute event was found to be a severe and exacerbated form of nonalcoholic steatohepatitis (NASH), a novel entry in the natural history of non-alcoholic fatty liver disease. This novel disease entity was described partially, 17 years before by Caldwell et al. We discuss current literature, pertinent features, and outcomes associated with a severe form of NASH, which is associated with high mortality.
- Published
- 2020
- Full Text
- View/download PDF
23. Outcomes and Toxicology of Herbal Drugs in Alcoholic Hepatitis - A Single Center Experience from India.
- Author
-
Philips CA, Rajesh S, George T, Ahamed R, Kumbar S, and Augustine P
- Abstract
Background and Aims: We aimed to study clinical outcomes and liver biopsy features of alcoholic hepatitis (AH) patients on complementary and alternative medicines (CAMs) and to analyze the retrieved drugs for chemical and toxic components linked to drug-induced liver injury. Methods: We retrospectively assessed clinical, biochemical and liver biopsy features of AH patients on CAM with drug-induced liver injury (AH-CAM, n = 27) and compared them to a control group (classical AH, n = 29) on standard of care. Patients without liver biopsy evaluation and other causes for liver disease were excluded. Samples of the CAMs ( n = 42) from patients were retrieved and assessed for chemical and toxins. Results: All were males, and significantly worse clinical presentation, biochemical severity, and liver disease scores were notable in patients with AH-CAM. Traditional Ayurvedic-polyherbal formulations were the most commonly used CAM. On liver histology, varying grades of severe-necrosis, severe hepatocellular, canalicular, cholangiolar cholestasis with predominant lymphocytic-portal-inflammation and varying grades of interface-hepatitis were noted in AH-CAM. Analysis of CAMs revealed presence of heavy metals up to 100,000 times above detectable range and adulterants, such as antibiotics, chemotherapy agents, nonsteroidal anti-inflammatory drugs, alcohols, antidepressants, anxiolytics, and recreational drugs. On follow up, a significantly higher number of patients with AH on CAM died at end of 1, 3- and-6-months compared to controls (37% vs. 83%, 29% vs. 62%, 18% vs. 52% respectively; p < 0.001). Conclusions: Patients with AH and CAM-related drug-induced liver injury have extremely poor short-term survival in the absence of liver transplantation compared to those patients with AH on evidence-based management. Early transplant referral and educating on and curbing of CAM use in severe liver disease through strict monitoring of unregulated traditional health practices can help ease the burden of liver-related death., Competing Interests: The authors have no conflict of interests related to this publication., (© 2019 Authors.)
- Published
- 2019
- Full Text
- View/download PDF
24. Lead modulated Heme synthesis inducing oxidative stress mediated Genotoxicity in Drosophila melanogaster.
- Author
-
Olakkaran S, Antony A, Kizhakke Purayil A, Tilagul Kumbar S, and Hunasanahally Puttaswamygowda G
- Subjects
- Animals, Catalase metabolism, Drosophila melanogaster physiology, Glutathione metabolism, Porphobilinogen Synthase metabolism, Superoxide Dismutase metabolism, Drosophila melanogaster drug effects, Heme metabolism, Lead toxicity, Mutagens toxicity, Oxidative Stress physiology
- Abstract
The mechanism of lead (Pb) modulated heme synthesis pathway induced oxidative stress mediated genotoxicity using standard (ST) and high bioactivation (HB) crosses of Drosophila melanogaster was addressed in the present study. Third instar larvae derived from the ST or HB crosses were reared in sub lethal concentrations of lead acetate (PbAc) treated food media and showed that Pb was readily taken up and accumulated in the said crosses. Pb modulated heme synthesis was evident by significant reductions of δ-aminolevulinic acid dehydratase (δ-ALA-D) and cytochrome P450 (CYP450) and increased accumulation of δ-aminolevulinic acid (δ-ALA). The results have also demonstrated that Pb induced oxidative stress by overproducing reactive oxygen species (ROS) and lipid peroxidation (LPO) and depletion of the antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT), glutathione (GSH) and glutathione-s-transferase (GST). Wing somatic mutation and recombination test (SMART) using ST and HB crosses revealed that Pb is mutagenic and weakly recombinogenic. By employing larval hemocytes, there was an increase in percent of tail DNA in alkaline comet compared to that of neutral comet revealing the DNA single strand breaks were the products of Pb modulated heme synthesis pathway induced oxidative free radicals. Based on these findings, it can be concluded that Pb modulated heme synthesis pathway induces oxidative stress that mediates the genotoxicity in D. melanogaster., (Copyright © 2018 Elsevier B.V. All rights reserved.)
- Published
- 2018
- Full Text
- View/download PDF
25. Ultrasound-Guided Fenestration of the Carpal Ligament Using a Double-Needle Approach.
- Author
-
Hwang GE, Kumbar S, Stitik T, Georgy JS, and Hanna H
- Subjects
- Aged, Humans, Male, Median Nerve diagnostic imaging, Needles, Ultrasonography, Interventional, Carpal Tunnel Syndrome therapy, Dissection instrumentation, Dissection methods, Ligaments, Articular diagnostic imaging
- Abstract
Injection techniques for carpal tunnel syndrome have evolved from landmark palpation injection techniques to more accurate ultrasound-guided approaches. Presented is a case report describing a technique serendipitously discovered during a carpal ligament fenestration. The case involved a 66-year-old man with a diagnosis of carpal tunnel syndrome. After a failed attempt at treatment using a wrist splint and activity modification, he was treated by median nerve hydrodissection with 100% temporary pain relief. When his symptoms recurred, a carpal tunnel combined hydrodissection/fenestration technique was performed. Because of difficulty extricating the carpal ligament from the median nerve with the first needle, which was placed longitudinal to the median nerve, a second needle was placed transverse to the median nerve to aid in hydrodissection. The second needle was left in because it was found to be helpful in maintaining a safe distance between the median nerve and the carpal ligament by intermittent injection through the second needle. The patient reported 70% relief of his symptoms at 2-week follow-up and 50% sustained relief at 3 months. A 2-needle technique is feasible and can be helpful during median nerve hydrodissection/carpal ligament fenestration when technical or anatomical issues arise preventing treatment using the traditional single needle approach. This double needle approach allows for use of injectate to maintain separation between the median nerve and the ligament during the fenestration.
- Published
- 2017
- Full Text
- View/download PDF
26. Improving Coccyx Radiographs in Emergency Departments.
- Author
-
Foye PM, Kumbar S, and Koon C
- Published
- 2016
- Full Text
- View/download PDF
27. Novel tubular composite matrix for bone repair.
- Author
-
Kofron MD, Cooper JA Jr, Kumbar SG, and Laurencin CT
- Subjects
- Animals, Bone Marrow Cells cytology, Bone Regeneration, Cell Adhesion, Cell Proliferation, Cells, Cultured, Compressive Strength, Durapatite isolation & purification, Hot Temperature, Lactic Acid isolation & purification, Materials Testing, Microscopy, Electron, Scanning, Microspheres, Polyglycolic Acid isolation & purification, Polylactic Acid-Polyglycolic Acid Copolymer, Polymers isolation & purification, Rats, Stromal Cells cytology, Tissue Engineering, Bone Substitutes isolation & purification
- Abstract
Tissue engineering develops organ replacements to overcome the limitations associated with autografts and allografts. The work presented here details the development of biodegradable, porous, three-dimensional polymer-ceramic-sintered microsphere matrices to support bone regeneration. Poly(lactide-co-glycolide)/hydroxyapatite microspheres were formed using solvent evaporation technique. Individual microspheres were placed in a cylindrical mold and sintered at various temperatures. Scaffolds were characterized using scanning electron microscopy, mercury porosimetry, and mechanical testing in compression. After varying the temperature of sintering, a single temperature was selected and the time of sintering was varied. Mechanical testing indicated that as the sintering temperature or time was increased, the elastic modulus, compressive strength, maximum compressive load, and energy at failure significantly increased. Furthermore, increasing the sintering temperature or time resulted in a decreased porosity and the spherical morphology of the microspheres was lost as the microspheres blended together. To more closely mimic the bone marrow cavity observed in native bone tissue, tubular composite-sintered microsphere matrices were formed. These scaffolds demonstrated no statistically significant difference in compressive mechanical properties when compared with cylindrical composite-sintered microsphere matrices of the same dimension. One potential application for these scaffolds is bone regeneration.
- Published
- 2007
- Full Text
- View/download PDF
28. Structural and nanoindentation studies of stem cell-based tissue-engineered bone.
- Author
-
Pelled G, Tai K, Sheyn D, Zilberman Y, Kumbar S, Nair LS, Laurencin CT, Gazit D, and Ortiz C
- Subjects
- Biomechanical Phenomena, Bone and Bones pathology, Microscopy, Atomic Force, Bone Substitutes chemistry, Bone and Bones physiology, Nanotechnology, Stem Cells, Tissue Engineering
- Abstract
Stem cell-based gene therapy and tissue engineering have been shown to be an efficient method for the regeneration of critical-sized bone defects. Despite being an area of active research over the last decade, no knowledge of the intrinsic ultrastructural and nanomechanical properties of such bone tissue exists. In this study, we report the nanomechanical properties of engineered bone tissue derived from genetically modified mesenchymal stem cells (MSCs) overexpressing the rhBMP2 gene, grown in vivo in the thigh muscle of immunocompetent mice for 4 weeks, compared to femoral bone adjacent to the transplantation site. The two types of bone had similar mineral contents (61 and 65 wt% for engineered and femoral bone, respectively), overall microstructures showing lacunae and canaliculi (both measured by back-scattered electron microscopy), chemical compositions (measured by energy dispersive X-ray analysis), and nanoscale topographical morphologies (measured by tapping-mode atomic force microscopy imaging or TMAFM). Nanoindentation experiments revealed that the small length scale mechanical properties were statistically different with the femoral bone (indented parallel to the bone long axis) being stiffer and harder (apparent elastic modulus, E approximately 27.3+/-10.5 GPa and hardness, H approximately 1.0+/-0.7G Pa) than the genetically engineered bone (E approximately 19.8+/-5.6 GPa, H approximately 0.9+/-0.4G Pa). TMAFM imaging showed clear residual indents characteristic of viscoelastic plastic deformation for both types of bone. However, fine differences in the residual indent area (smaller for the engineered bone), pile up (smaller for the engineered bone), and fracture mechanisms (microcracks for the engineered bone) were observed with the genetically engineered bone behaving more brittle than the femoral control.
- Published
- 2007
- Full Text
- View/download PDF
29. Frequency of feeding and formation of bone growth marks in frog, Rana cyanophlyctis (Schn.).
- Author
-
Kumbar SM and Pancharatna K
- Subjects
- Animals, Body Constitution, Body Mass Index, Climate, Bone Development, Bone and Bones anatomy & histology, Feeding Behavior physiology, Ranidae physiology
- Abstract
Frogs, R. cyanophlyctis (n = 45) divided into four groups, were exposed to different feeding regimens (live guppies were used as food) such as, daily, alternate day, every fourth day and weekly feeding for 5 months, during wet months of the year (April-September). Two toe clippings were made, one at the beginning and the other at the termination of the experiment. Clipped toes were demineralized, and processed for histology. In 6 out of 45 frogs one line of arrested growth (LAG) was present in the phalangeal histology at the beginning of the experiment while, at the termination of experiment 34 out of 43 frogs exhibited one LAG each indicating that in 26 frogs LAG appeared freshly during the experimental period. The fact that LAGs are formed in regularly fed frogs suggests the humid weather/seasonal rainfall may play relatively important role than the feeding in cyclic bone growth and formation of growth marks in this frog.
- Published
- 2002
30. Effect of androgens on oviductal growth in skipper frog Rana cyanophlyctis.
- Author
-
Pancharatna K, Rajapurohit SV, Hiregoudar SR, and Kumbar SM
- Subjects
- Animals, Female, Hypertrophy, Ovariectomy, Oviducts pathology, Ranidae, Estradiol pharmacology, Oviducts drug effects, Testosterone pharmacology
- Abstract
Effects of exogenous androgens (testosterone, testosterone propionate and dihydrotestosterone) and estradiol-17beta on the oviductal growth/hypertrophy were studied in young and bilaterally ovariectomized (BLO) adult frogs (Rana cyanophlyctis) during postbreeding phase of the reproductive cycle. Estradiol-17beta injections induced oviductal hypertrophy to the maximal extent among hormone treated groups. In androgen treated frogs also there was an increase in the oviductal dry weight and protein content both in young and BLO adult frogs, suggesting the role of endogenous androgens in controlling the growth of oviduct in R. cyanophlyctis.
- Published
- 2001
31. Determination of age, longevity and age at reproduction of the frog Microhyla ornata by skeletochronology.
- Author
-
Kumbar SM and Pancharatna K
- Subjects
- Age Determination by Skeleton, Aging, Animals, Anura growth & development, Climate, Female, Femur anatomy & histology, Femur growth & development, Longevity, Male, Metatarsal Bones anatomy & histology, Metatarsal Bones growth & development, Ovary anatomy & histology, Reproduction, Sex Factors, Sexual Maturation, Testis anatomy & histology, Time Factors, Anura anatomy & histology, Anura physiology, Bone and Bones anatomy & histology
- Abstract
Skeletochronological estimation of age, longevity, age at sexual maturity and breeding of Microhyla ornata was done. Frogs (n=62) were collected locally in August (rainy season) 1997 and brought to the laboratory. Body mass and snout-vent-length (SVL) of each frog was recorded; the 4th toe of both the hind limbs was clipped under anaesthesia, fixed in 10% formalin, demineralized in 5% nitric acid and processed for histology. Limb bones (femur, humerus, tibiofibula and radioulna) of 6 large sized frogs were also processed for skeletochronology in order to study the rate of resorption. Gonads of 25 frogs (belonging to different body size ranges) were processed for histology in order to ascertain the gametogenic status of individual frogs. One to four growth rings consisting of growth zones and lines of arrested growth (LAGs) were noticed in frogs of different body sizes; the number of LAGs remained identical in all the limb bones and phalanges in 5 out of 6 frogs. Back calculation indicated that the resorption rate is very low in this frog. Male frogs possessed sperm bundles in seminiferous tubules in the 1st year, while females showed yolky follicles in the ovary in the 2nd year. Frogs found in amplexus were 3 5 years old. The results suggest that this frog may live for a maximum of 5 years in the natural population.
- Published
- 2001
- Full Text
- View/download PDF
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.