RESUMO
The tumor microenvironment (TME) is like the Referee of a soccer match who has constant eyes on the activity of all players, such as cells, acellular stroma components, and signaling molecules for the successful completion of the game, that is, tumorigenesis. The cooperation among all the "team members" determines the characteristics of tumor, such as the hypoxic and acidic niche, stiffer mechanical properties, or dilated vasculature. Like in soccer, each TME is different. This heterogeneity makes it challenging to fully understand the intratumor dynamics, particularly among different tumor subpopulations and their role in therapeutic response or resistance. Further, during metastasis, tumor cells can disseminate to a secondary organ, a critical event responsible for approximately 90% of the deaths in cancer patients. The recapitulation of the rapidly changing TME in the laboratory is crucial to improve patients' prognosis for unraveling key mechanisms of tumorigenesis and developing better drugs. Hence, in this chapter, we provide an overview of the characteristic features of the TME and how to model them, followed by a brief description of the limitations of existing in vitro platforms. Finally, various attempts at simulating the TME using microfluidic platforms are highlighted. The chapter ends with the concerns that need to be addressed for designing more realistic and predictive tumor-on-a-chip platforms.
Assuntos
Dispositivos Lab-On-A-Chip , Neoplasias , Carcinogênese , Humanos , Microfluídica , Neoplasias/patologia , Microambiente TumoralRESUMO
Tamoxifen administration enhanced overall disease-free survival and diminished mortality rates in cancer patients. However, patients with breast cancer often fail to respond for tamoxifen therapy due to the development of a drug-resistant phenotype. Functional analysis and molecular studies suggest that protein mutation and dysregulation of survival signaling molecules such as epidermal growth factor receptor, vascular endothelial growth factor receptor 2, and Akt contribute to tamoxifen resistance. Various strategies, including combinatorial therapies, show chemosensitize tamoxifen-resistant cancers. Based on chemotoxicity issues, researchers are actively investigating alternative therapeutic strategies. In the current study, we fabricate a mesoporous silica gold cluster nanodrug delivery system that displays exceptional tumor-targeting capability, thus promoting accretion of drug indices at the tumor site. We employ dual drugs, ZD6474, and epigallocatechin gallate (EGCG) that inhibit EGFR2, VEGFR2, and Akt signaling pathways since changes in these signaling pathways confer tamoxifen resistance in MCF 7 and T-47D cells. Mesoporous silica gold cluster nanodrug delivery of ZD6474 and EGCG sensitize tamoxifen-resistant cells to apoptosis. Western and immune-histochemical analyses confirmed the apoptotic inducing properties of the nanoformulation. Overall, results with these silica gold nanoclusters suggest that they may be a potent nanoformulation against chemoresistant cancers.
Assuntos
Antineoplásicos/farmacologia , Neoplasias da Mama/tratamento farmacológico , Portadores de Fármacos/química , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Animais , Antineoplásicos/uso terapêutico , Apoptose/efeitos dos fármacos , Neoplasias da Mama/patologia , Catequina/análogos & derivados , Catequina/farmacologia , Catequina/uso terapêutico , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Engenharia Química , Receptores ErbB/metabolismo , Feminino , Ouro/química , Humanos , Nanopartículas Metálicas/química , Camundongos Nus , Piperidinas/farmacologia , Piperidinas/uso terapêutico , Porosidade , Proteínas Proto-Oncogênicas c-akt/metabolismo , Quinazolinas/farmacologia , Quinazolinas/uso terapêutico , Dióxido de Silício/química , Tamoxifeno/farmacologia , Tamoxifeno/uso terapêutico , Resultado do Tratamento , Receptor 2 de Fatores de Crescimento do Endotélio Vascular/metabolismo , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
The current study deals with the fabrication and characterization of blended nanofibrous scaffolds of tropical tasar silk fibroin of Antheraea mylitta and poly (Ð-caprolactone) to act as an ideal scaffold for bone regeneration. The use of poly (Ð-caprolactone) in osteogenesis is well-recognized. At the same time, the osteoconductive nature of the non-mulberry tasar fibroin is also established due to its internal integrin binding peptide RGD (Arg-Gly-Asp) sequences, which enhance cellular interaction and proliferation. Considering that the materials have the required and favorable properties, the blends are formed using an equal volume ratio of fibroin (2 and 4 wt%) and poly (Ð-caprolactone) solution (10 wt%) to fabricate nanofibers. The nanofibers possess an average diameter of 152 ± 18 nm (2 % fibroin/PCL) and 175 ± 15 nm (4% fibroin/PCL). The results of Fourier transform infrared spectroscopy substantiates the preservation of the secondary structure of the fibroin in the blends indicating the structural stability of the neo-matrix. With an increase in the fibroin percentage, the hydrophobicity and thermal stability of the matrices as measured from melting temperature Tm (using DSC) decrease, while the mechanical strength is improved. The blended nanofibrous scaffolds are biodegradable, and support the viability and proliferation of human osteoblast-like cells as observed through scanning electron and confocal microscopes. Alkaline phosphatase assay indicates the cell proliferation and the generation of the neo-bone matrix. Taken together, these findings illustrate that the silk-poly (Ð-caprolactone) blended nanofibrous scaffolds have an excellent prospect as scaffolding material in bone tissue engineering.
Assuntos
Osso e Ossos/fisiologia , Fibroínas/farmacologia , Nanofibras/química , Oligopeptídeos/farmacologia , Poliésteres/farmacologia , Engenharia Tecidual/métodos , Fosfatase Alcalina/metabolismo , Animais , Osso e Ossos/efeitos dos fármacos , Calcificação Fisiológica/efeitos dos fármacos , Varredura Diferencial de Calorimetria , Adesão Celular/efeitos dos fármacos , Linhagem Celular , Proliferação de Células/efeitos dos fármacos , Forma Celular/efeitos dos fármacos , Endopeptidase K/metabolismo , Humanos , Nanofibras/ultraestrutura , Osteoblastos/citologia , Osteoblastos/efeitos dos fármacos , Osteoblastos/metabolismo , Espectroscopia de Infravermelho com Transformada de Fourier , Estresse Mecânico , Temperatura , Resistência à Tração/efeitos dos fármacos , Alicerces Teciduais/químicaRESUMO
This cross sectional observational study was done in the Department of ENT & Head-Neck Surgery, Mymensingh Medical College, Bangladesh from January 2013 to July 2014. Fifty (50) cases of carcinoma larynx were purposively selected. Clinically diagnosed cases of carcinoma larynx and histologically proven squamous cell carcinoma were included. Among 50 cases age ranged from 35-75 years with an average age of 58.1 years. Maximum patients were in 5th and 6th decades with male-female ratio 16:1. Most of the patient (78%) came from rural areas and came from low socio-economic condition (58%); maximum patients were cultivator (42%) & illiterate (50%). Smoking was the commonest (64%) personal habit. The other common personal habits were chewing of Betel nut & leaf (44%) and chewing of Tobacco (36%). Most of them have more than one habit.
Assuntos
Carcinoma de Células Escamosas/epidemiologia , Neoplasias Laríngeas/epidemiologia , Tabaco sem Fumaça/efeitos adversos , Adulto , Idoso , Areca/efeitos adversos , Bangladesh/epidemiologia , Carcinoma de Células Escamosas/etiologia , Carcinoma de Células Escamosas/patologia , Estudos Transversais , Feminino , Comportamentos Relacionados com a Saúde , Humanos , Neoplasias Laríngeas/etiologia , Neoplasias Laríngeas/patologia , Masculino , Pessoa de Meia-Idade , Fatores de Risco , Fumar/efeitos adversos , Fatores SocioeconômicosRESUMO
Polymeric and biodegradable nanoparticles are frequently used in drug delivery systems. In this study silk fibroin-albumin blended nanoparticles were prepared using the desolvation method without any surfactant. These nanoparticles are easily internalized by the cells, reside within perinuclear spaces and act as carriers for delivery of the model drug methotrexate. Methotrexate loaded nanoparticles have better encapsulation efficiency, drug loading ability and less toxicity. The in vitro release behavior of methotrexate from the nanoparticles suggests that about 85% of the drug gets released after 12 days. The encapsulation and loading of a drug would depend on factors such as size, charge and hydrophobicity, which affect drug release. MTT assay and conjugation of particles with FITC demonstrate that the silk fibroin-albumin nanoparticles do not affect the viability and biocompatibility of cells. This blended nanoparticle, therefore, could be a promising nanocarrier for the delivery of drugs and other bioactive molecules.
Assuntos
Antimetabólitos Antineoplásicos/administração & dosagem , Portadores de Fármacos/química , Fibroínas/química , Metotrexato/administração & dosagem , Nanopartículas/química , Albumina Sérica/química , Animais , Antimetabólitos Antineoplásicos/farmacologia , Bombyx/química , Neoplasias da Mama/tratamento farmacológico , Linhagem Celular , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Feminino , Fibroínas/toxicidade , Hemólise/efeitos dos fármacos , Humanos , Metotrexato/farmacologia , Nanopartículas/toxicidade , Nanopartículas/ultraestrutura , Tamanho da Partícula , Albumina Sérica/toxicidade , Espectroscopia de Infravermelho com Transformada de FourierRESUMO
Due to difficult anatomical position nasopharyngeal carcinoma (NPC) is always challenging problems both from the diagnostic and therapeutic corner. A 24 years old lady came to our Department of Otolaryngology and Head-Neck Surgery with the complaints of epistaxis, right sided neck swelling, nasal obstruction and headache. On digital palpation Nasopharyngeal mass was found. We took biopsy from nasopharynx under indirect vision but report was not conclusive. Then we did CT scan, nasendoscopy. Nasendoscopy showed bilateral ethmoidal polyp with nasopharyngeal mass. We took biopsy from the nasopharyngeal mass and confirmed the diagnosis.
Assuntos
Neoplasias Nasofaríngeas/diagnóstico , Carcinoma , Seio Etmoidal/diagnóstico por imagem , Feminino , Humanos , Metástase Linfática , Carcinoma Nasofaríngeo , Neoplasias Nasofaríngeas/diagnóstico por imagem , Neoplasias Nasofaríngeas/patologia , Pólipos/diagnóstico por imagem , Tomografia Computadorizada por Raios X , Adulto JovemRESUMO
Rheumatoid arthritis (RA) is an autoimmune and chronic inflammatory disease characterized by joint inflammation. Since the inflammatory condition plays an important role in the disease process, it is important to develop and test new therapeutic approaches that specifically target and treat joint inflammation. In this study, a human 3D inflammatory cartilage-on-a-chip model was established to test the therapeutic efficacy of anti-TNFα mAb-CS/PAMAM dendrimer NPs loaded-Tyramine-Gellan Gum in the treatment of inflammation. The results showed that the proposed therapeutic approach applied to the human monocyte cell line (THP-1) and human chondrogenic primary cells (hCH) cell-based inflammation system revealed an anti-inflammatory capacity that increased over 14 days. It was also possible to observe that Coll type II was highly expressed by inflamed hCH upon the culture with anti-TNF α mAb-CS/PAMAM dendrimer NPs, indicating that the hCH cells were able maintain their biological function. The developed preclinical model allowed us to provide more robust data on the potential therapeutic effect of anti-TNF α mAb-CS/PAMAM dendrimer NPs loaded-Ty-GG hydrogel in a physiologically relevant model.
Assuntos
Anti-Inflamatórios não Esteroides/uso terapêutico , Anticorpos Monoclonais/uso terapêutico , Materiais Biocompatíveis/uso terapêutico , Dendrímeros/uso terapêutico , Dispositivos Lab-On-A-Chip , Inibidores do Fator de Necrose Tumoral/uso terapêutico , Anti-Inflamatórios não Esteroides/síntese química , Anti-Inflamatórios não Esteroides/química , Anticorpos Monoclonais/química , Artrite Reumatoide/tratamento farmacológico , Materiais Biocompatíveis/síntese química , Materiais Biocompatíveis/química , Células Cultivadas , Dendrímeros/síntese química , Dendrímeros/química , Humanos , Hidrogéis/química , Inflamação/tratamento farmacológico , Nanopartículas/química , Polissacarídeos Bacterianos/química , Inibidores do Fator de Necrose Tumoral/síntese química , Inibidores do Fator de Necrose Tumoral/química , Fator de Necrose Tumoral alfa/antagonistas & inibidores , Tiramina/químicaRESUMO
Seventy patients of differentiated thyroid carcinoma (DTC) irrespective of age and sex were selected in ENT Department of Bangabandhu Sheikh Mujib Medical University, Dhaka Medical College Hospital and Rangpur Medical College Hospital who were admitted from March 2003 to March 2005. Female were more commonly affected (2.6:1) Papillary carcinoma was more common in 31-50 years of age and follicular carcinoma (ca) common in 41-50 years of age. Among the differentiated thyroid carcinoma papillary carcinoma found 77.15% and follicular ca. found 22.85%. Lymph node metastasis was more common in papillary (35%) than follicular carcinoma (12.5%). But distant metastasis was more common in follicular (12.5%) than papillary carcinoma (3.70). Maximum lymph node metastasis was found in level 3(55%), level 2(45%).
Assuntos
Neoplasias da Glândula Tireoide/patologia , Adolescente , Adulto , Idoso , Diferenciação Celular , Criança , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Metástase NeoplásicaRESUMO
Mineralization is a natural process leading to the formation of mineralized tissue such as bone. The chief mineral component of bone is hydroxyapatite (HAp), which is deposited using an organic template like fibrillar Collagen I under physiological condition. Fibrous silk fibroin is structurally homologous to collagen and acts as nucleation site for HAp mineralization when immersed in simulated body fluid (SBF) or fetal bovine serum (FBS), therefore, considered as popular bone regeneration biomaterial. Hence, the mineralization behavior of silk fibroin self-assembled gellan gum enriched 3D hydrogels is investigated under conditions closer to physiological ones using SBF as well as FBS, and also in presence of cells (e.g. human adipose tissue-derived stem cells, ASCs). Incorporation of silk fibroin induces the mineralization in acellular spongy-like hydrogels in composition dependent manner, confirmed by SEM-EDS analysis. In contrast, ASCs mediated mineralization is found in all hydrogel compositions of 3 weeks post-culture under osteogenic conditions as demonstrated by gene expression profile and Alizarin Red S staining. This is perhaps due to the co-existence of fibroin and FBS together induce cell-mediated mineralization. The blending of fibroin offers cheap alternative strategy to improve or guide the repair of mineralized tissue using gellan gum-based biomaterials.
Assuntos
Calcificação Fisiológica/efeitos dos fármacos , Fibroínas/química , Fibroínas/farmacologia , Hidrogéis/química , Polissacarídeos Bacterianos/química , Tecido Adiposo/citologia , Diferenciação Celular/efeitos dos fármacos , Humanos , Osteogênese/efeitos dos fármacos , Células-Tronco/citologia , Células-Tronco/efeitos dos fármacosRESUMO
Micropatterning/micromolding of protein molecules has played a significant role in developing biosensors, micro arrays, and tissue engineering devices for cellular investigations. Relevantly, there have been ample scopes for silk to be used as natural biomaterial in tissue engineering applications due to its attractive properties such as slow-controllable degradation, mechanical robustness, and inherent biocompatibility. In this paper, we report the fabrication of micromolded silk fibroin matrices, which have essentially been utilized to study cell-surface interactions. Fibroin protein has been isolated from the silk glands of nonmulberry Indian tropical tasar silkworms, Antheraea mylitta. The surface uniformity has been investigated using atomic force microscopy following the fabrication of silk micromolds. Subsequently, cellular interactions in terms of cell attachment, spreading, mitochondrial activity and proliferation have been studied in vitro using feline fibroblasts. Results have indicated a long term stability of patterns in micromolded silk matrices and negligible swelling. The versatility of described silk dissolution method coupled with ability to process large amount of silk protein into micromolded matrices and controllable surface topology may augment the desirability of silk fibroin as a natural biomaterial for bioengineering and biotechnological applications.
Assuntos
Técnicas de Cultura de Células/métodos , Matriz Extracelular/química , Fibroblastos/citologia , Fibroblastos/fisiologia , Fibroínas/química , Fibroínas/ultraestrutura , Animais , Gatos , Adesão Celular/fisiologia , Linhagem Celular , Movimento Celular/fisiologia , Propriedades de SuperfícieRESUMO
In recent times self-assembled micellar nanoparticles have been successfully employed in tissue engineering for targeted drug delivery applications. In this review, silk sericin protein from non-mulberry Antheraea mylitta tropical tasar silk cocoons was blended with pluronic F-127 and F-87 in the presence of solvents to achieve self-assembled micellar nanostructures capable of carrying both hydrophilic (FITC-inulin) and hydrophobic (anticancer drug paclitaxel) drugs. The fabricated nanoparticles were subsequently characterized for their size distribution, drug loading capability, cellular uptake and cytotoxicity. Nanoparticle sizes ranged between 100 and 110 nm in diameter as confirmed by dynamic light scattering. Rapid uptake of these particles into cells was observed in in vitro cellular uptake studies using breast cancer MCF-7 cells. In vitro cytotoxicity assay using paclitaxel-loaded nanoparticles against breast cancer cells showed promising results comparable to free paclitaxel drugs. Drug-encapsulated nanoparticle-induced apoptosis in MCF-7 cells was confirmed by FACS and confocal microscopic studies using Annexin V staining. Up-regulation of pro-apoptotic protein Bax, down-regulation of anti-apoptotic protein Bcl-2 and cleavage of regulatory protein PARP through Western blot analysis suggested further drug-induced apoptosis in cells. This study projects silk sericin protein as an alternative natural biomaterial for fabrication of self-assembled nanoparticles in the presence of poloxamer for successful delivery of both hydrophobic and hydrophilic drugs to target sites.
Assuntos
Portadores de Fármacos/química , Sistemas de Liberação de Medicamentos , Interações Hidrofóbicas e Hidrofílicas , Nanopartículas/química , Poloxâmero/química , Sericinas/química , Seda/química , Animais , Anexina A5/metabolismo , Antineoplásicos/farmacologia , Western Blotting , Morte Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Citometria de Fluxo , Fluoresceína-5-Isotiocianato/metabolismo , Humanos , Microscopia Confocal , Nanopartículas/ultraestrutura , Paclitaxel/farmacologia , Tamanho da Partícula , Propriedades de Superfície/efeitos dos fármacosRESUMO
This study reports the effects of treatment with various concentrations of organic solvents for varying time points on matrices of fibroin, a silk protein isolated from the mulberry silkworm, Bombyx mori, which in native form has been extensively used in tissue engineering. Treatment of pure fibroin as well as polyethylene glycol- blended films with 90% organic solvent for 60 min induces optimal surface hydrophobicity and maximum conversion of the secondary structure from random coil to beta sheet. Long-term cell viability studies reveal that methanol and isopropanol-treated pure and blended films support cell adhesion, proliferation, and viability.
Assuntos
Materiais Biocompatíveis/química , Fibroblastos/citologia , Fibroínas/química , Polietilenoglicóis/química , Seda/química , 2-Propanol/química , Animais , Adesão Celular/fisiologia , Linhagem Celular , Sobrevivência Celular/fisiologia , Camundongos , Propriedades de SuperfícieRESUMO
Osteosarcoma is one of the most common metastatic bone cancers, which results in significant morbidity and mortality. Unfolding of effectual therapeutic strategies against osteosarcoma is impeded because of the absence of adequate animal models, which can truly recapitulate disease biology of humans. Tissue engineering provides an opportunity to develop physiologically relevant, reproducible, and tunable in vitro platforms to investigate the interactions of osteosarcoma cells with its microenvironment. Adipose-derived stem cells (ASCs) are detected adjacent to osteosarcoma masses and are considered to have protumor effects. Hence, the present study focuses on investigating the role of reactive ASCs in formation of spheroids of osteosarcoma cells (Saos 2) within a three-dimensional (3D) niche, which is created using gellan gum (GG)-silk fibroin. By modifying the blending ratio of GG-silk, the optimum stiffness of the resultant hydrogels such as GG and GG75: S25 is obtained for cancer spheroid formation. This work indicates that the co-existence of cancer and stem cells can form a spheroid, the hallmark of cancer, only in particular microenvironment stiffness. The incorporation of fibrillar silk fibroin within the hydrophilic network of GG in GG75: S25 spongy-like hydrogels closely mimics the stiffness of commercially established cancer biomaterials (e.g., Matrigel, HyStem). The GG75: S25 hydrogel maintains the metabolically active construct for a longer time with elevated expression of osteopontin, osteocalcin, RUNX 2, and bone sialoprotein genes, the biomarkers of osteosarcoma, compared to GG. The GG75: S25 construct also exhibits intense alkaline phosphatase expression in immunohistochemistry compared to GG, indicating itspotentiality to serve as biomimetic niche to model osteosarcoma. Taken together, the GG-silk fibroin-blended spongy-like hydrogel is envisioned as an alternative low-cost platform for 3D cancer modeling.
Assuntos
Adipócitos/metabolismo , Tecido Adiposo/metabolismo , Neoplasias Ósseas/metabolismo , Fibroínas/química , Hidrogéis/química , Modelos Biológicos , Osteossarcoma/metabolismo , Esferoides Celulares/metabolismo , Células-Tronco/metabolismo , Alicerces Teciduais/química , Adipócitos/patologia , Tecido Adiposo/patologia , Neoplasias Ósseas/patologia , Linhagem Celular Tumoral , Humanos , Osteossarcoma/patologia , Esferoides Celulares/patologia , Células-Tronco/patologia , Engenharia TecidualRESUMO
The importance of silk protein has increased because of its potential use as a natural biopolymer for tissue engineering and biomedical applications. In this report we show a novel and ecofriendly method for dissolution of gland silk protein fibroin. Non-mulberry silk fibroin from mature fifth instar larvae of Antheraea mylitta was found to be optimally soluble in 1% (w/v) anionic surfactant sodium dodecyl sulfate (SDS). Regenerated fibroin showed distinct bands of approximately 395 and 197 kDa on electrophoresis in non-reducing and reducing conditions, respectively. Enhanced fibroin dissolution via internalization of hydrophobic amino groups inside a hydrophilic amino acid core in the form of micelles was observed. Prolonged storage stability without gelation of SDS-extracted fibroin was seen. Atomic force microscopy showed micellar aggregation with mean micellar aggregation size of 8 nm. Circular dichroism spectroscopy revealed predominantly helical conformation due to surfactant addition with internal protein conformational changes as revealed by fluorescence spectroscopic studies.
Assuntos
Bombyx/metabolismo , Fibroínas/química , Fibroínas/ultraestrutura , Dodecilsulfato de Sódio/química , Tensoativos/química , Animais , Ânions , Conformação Proteica , Desnaturação ProteicaRESUMO
Silk fibroin from silk gland of Bombyx mori 5th instar larvae was utilized to fabricate films, which may find possible applications as two-dimensional matrices for tissue engineering. Bombyx mori cocoon fibroin is well characterized as potential biomaterial by virtue of its good mechanical strength, water stability, thermal properties, surface roughness and biocompatibility. The present study aims to characterize the biophysical, thermal, mechanical, rheological, swelling properties along with spectroscopic analysis, surface morphology and biocompatibility of the silk gland fibroin films compared with cocoon fibroin. Fibroin solutions showed increased turbidity and shear thinning at higher concentration. The films after methanol treatment swelled moderately and were less hydrophilic compared to the untreated. The spectroscopic analysis of the films illustrated the presence of various amide peaks and conformational transition from random coil to beta sheet on methanol treatment. X-ray diffraction studies also confirmed the secondary structure. Thermogravimetric analysis showed distinct weight loss of the films. The films were mechanically stronger and AFM studies showed surfaces were rougher on methanol treatment. The matrices were biocompatible and supported L929 mouse fibroblast cell growth and proliferation. The results substantiate the silk gland fibroin films as potential biomaterial matrices.
Assuntos
Materiais Biocompatíveis/química , Bombyx/metabolismo , Técnicas de Cultura de Células/métodos , Matriz Extracelular/química , Fibroblastos/fisiologia , Morus/química , Seda/química , Engenharia Tecidual/métodos , Animais , Linhagem Celular , Proliferação de Células , Sobrevivência Celular , Módulo de Elasticidade , Fibroblastos/citologia , Camundongos , Seda/ultraestrutura , Propriedades de Superfície , Resistência à TraçãoRESUMO
Antheraea mylitta (Drury) is a tropical tasar-silk producing insect. Its populations occupying different ecological and geographical regions show a certain degree of phenotypic variability, for which they are known as "eco-races." The eco-races are exploited for tasar silk production, and they are classified on the basis of their geographical distribution and morphology, which is often misleading when their systematic position is considered. To understand the genetic variability among the different eco-races, we used the random amplified polymorphic DNA (RAPD) method. Eighty random decamer primers were taken for RAPD amplifications. In total, 415 reproducible bands were used to generate a distance matrix, and for the subsequent clustering with unweighted pair-group method with arithmetic average. The number of polymorphic bands detected by each primer ranged from 5 to 24, with a mean value of 14.1 per primer. Percentage polymorphism was 81.9, and genetic distance values ranged from a minimum of 0.0108 between Modal and Nalia eco-races to a maximum of 0.0244 between Modal and Andhra local. The RAPD profiles obtained using A14, BC07, and C17 primers substantially differentiate all 10 commercially important eco-races, and the phylogenetic tree obtained from the data closely follows their geographical separations.
Assuntos
Biomarcadores/química , Mariposas/genética , Animais , Ecossistema , Genética Populacional , Geografia , Índia , Técnica de Amplificação ao Acaso de DNA PolimórficoRESUMO
Cancer is a leading cause of mortality and morbidity worldwide. Around 90% of deaths are caused by metastasis and just 10% by primary tumor. The advancement of treatment approaches is not at the same rhythm of the disease; making cancer a focal target of biomedical research. To enhance the understanding and prompts the therapeutic delivery; concepts of tissue engineering are applied in the development of in vitro models that can bridge between 2D cell culture and animal models, mimicking tissue microenvironment. Tumor spheroid represents highly suitable 3D organoid-like framework elucidating the intra and inter cellular signaling of cancer, like that formed in physiological niche. However, spheroids are of limited value in studying critical biological phenomenon such as tumor-stroma interactions involving extra cellular matrix or immune system. Therefore, a compelling need of tailoring spheroid technologies with physiologically relevant biomaterials or in silico models, is ever emerging. The diagnostic and prognostic role of spheroids rearrangements within biomaterials or microfluidic channel is indicative of patient management; particularly for the decision of targeted therapy. Fragmented information on available in vitro spheroid models and lack of critical analysis on transformation aspects of these strategies; pushes the urge to comprehensively overview the recent technological advancements (e.g. bioprinting, micro-fluidic technologies or use of biomaterials to attain the third dimension) in the shed of translationable cancer research. In present article, relationships between current models and their possible exploitation in clinical success is explored with the highlight of existing challenges in defining therapeutic targets and screening of drug efficacy.
Assuntos
Materiais Biocompatíveis , Bioimpressão/métodos , Descoberta de Drogas/métodos , Modelos Biológicos , Esferoides Celulares/fisiologia , Animais , Humanos , Microfluídica/métodos , Neoplasias/tratamento farmacológico , Esferoides Celulares/efeitos dos fármacos , Células Tumorais CultivadasRESUMO
Nerve conduits are becoming increasingly popular for the repair of peripheral nerve injuries. Their ease of application and lack of donor site morbidity make them an attractive option for nerve repair in many situations. Today, there are many different conduits to choose in different sizes and materials, giving the reconstructive surgeon many options for any given clinical problem. However, to properly utilize these unique reconstructive tools, the peripheral nerve surgeon must be familiar not only with their standard indications but also with their functional limitations. In this review, the authors identify the common applications of nerve conduits, expected results, and shortcomings of current techniques. Furthermore, future directions for nerve conduit use are identified.
RESUMO
Sericin isolated from the cocoon of the tropical tasar silkmoth Antheraea mylitta showed three major bands, with the lowest 70 kDa. This band was purified by anion exchange chromatography. Immunoblotting with concanavalin-A suggests a glycoprotein and CD analysis of secondary structure includes beta-sheet. Amino acid analysis shows that the protein is enriched in glycine and serine while the mole percentages of these two amino acids are different from sericin of mulberry silkworm. An anti A. mylitta sericin antibody was able to cross-react with sericin from A. assamensis but not the sericin of Bombyx mori and Philosamia ricini. Immunoblot analysis with proteins isolated from middle silk gland of A. mylitta at different developmental stages of larva showed that the 70 kDa sericin is developmentally regulated. These data extend the range of biochemical features found in this unusual family of proteins and may help in developing an improved understanding of their role in forming environmentally stable fibroin fiber-sericin composite structures (cocoons).
Assuntos
Bombyx/química , Sericinas/química , Sericinas/isolamento & purificação , Clima Tropical , Sequência de Aminoácidos , Animais , Fenômenos Biofísicos , Biofísica , Dicroísmo Circular , Eletroforese em Gel de Poliacrilamida , Perfilação da Expressão Gênica , Larva/crescimento & desenvolvimento , Dados de Sequência Molecular , Peso Molecular , Estrutura Secundária de Proteína , Seda/biossínteseRESUMO
BACKGROUND: Adhesion formation remains a major complication following hernia repair surgery. Physical barriers though effective for adhesion prevention in clinical settings are associated with major disadvantages, therefore, needs further investigation. This study evaluates silk fibroin hydrogel as a physical barrier on polypropylene mesh for the prevention of adhesion following ventral hernia repair. STUDY DESIGN: Peritoneal explants were cultured on silk fibroin scaffold to evaluate its support for mesothelial cell growth. Full thickness uniform sized defects were created on the ventral abdominal wall of rabbits, and the defects were covered either with silk hydrogel coated polypropylene mesh or with plain polypropylene mesh as a control. The animals were killed after 1 month, and the adhesion formation was graded; healing response of peritoneum was evaluated by immunohistochemistry with calretinin, collagen staining of peritoneal sections, and expression of PCNA, collagen-I, TNFα, IL6 by real time PCR; and its adverse effect if any was determined. RESULTS: Silk fibroin scaffold showed excellent support for peritoneal cell growth in vitro and the cells expressed calretinin. A remarkable prevention of adhesion formation was observed in the animals implanted with silk hydrogel coated mesh compared to the control group; in these animals peritoneal healing was complete and predominantly by mesothelial cells with minimum fibrotic changes. Expression of inflammatory cytokines decreased compared to control animals, histology of abdominal organs, haematological and blood biochemical parameters remained normal. CONCLUSION: Therefore, silk hydrogel coating of polypropylene mesh can improve peritoneal healing, minimize adhesion formation, is safe and can augment the outcome of hernia surgery.