Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 19 de 19
Filtrar
1.
Laryngoscope ; 133(6): 1473-1479, 2023 06.
Artigo em Inglês | MEDLINE | ID: mdl-36960884

RESUMO

OBJECTIVE: Chinese herbal medicine (CHM) has been implemented as a form of treatment for olfactory dysfunction. In this study, we aimed to use a tailored Guizhi decoction for the treatment of traumatic olfactory dysfunction. METHODS: Patients who had lost olfactory function after experiencing head trauma and whose olfactory function was anosmic were selected. The eligible patients were randomly assigned to two groups. In the CHM group, a tailored Guizhi decoction was prescribed, with patients also undergoing olfactory training (OT). In the OT group, patients performed OT only. The olfactory function of each patient was evaluated by both the phenyl ethyl alcohol (PEA) odor detection threshold test and the traditional Chinese version of the University of Pennsylvania Smell Identification Test (TC-UPSIT), at both 3 and 6 months after the completion of treatment. RESULTS: A total of 38 patients in the CHM group and 40 in the OT group completed the study. The TC-UPSIT scores of patients slightly rose after treatment in both the CHM and OT groups. Nevertheless, there were no significant differences in TC-UPSIT scores before and after treatment in both groups. However, the PEA thresholds improved significantly in both CHM and OT groups (p = 0.005 and 0.016, respectively). Of note, there were no significant differences in threshold or identification scores between the CHM and OT groups. CONCLUSION: Our results show that adding a tailored Guizhi decoction to OT conferred a limited benefit to the olfactory function of patients experiencing traumatic anosmia. LEVEL OF EVIDENCE: 2 Laryngoscope, 133:1473-1479, 2023.


Assuntos
Medicamentos de Ervas Chinesas , Transtornos do Olfato , Álcool Feniletílico , Humanos , Transtornos do Olfato/tratamento farmacológico , Transtornos do Olfato/etiologia , Transtornos do Olfato/diagnóstico , Anosmia , Estudos Prospectivos , Medicamentos de Ervas Chinesas/uso terapêutico , Olfato
3.
Empir Econ ; 64(5): 2085-2103, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36320925

RESUMO

This paper examines whether the SAH orders, implemented in the USA from mid-March to late May 2020, improved air quality in the northeastern states. The estimates are based on panel data from the Environmental Protection Agency and an identification strategy that exploits the exogenous variation in the timing of the SAH orders. We find that the SAH orders reduced the concentrations of the air pollutants nitrogen dioxide ( NO 2 ) and carbon monoxide (CO), whose dominant source is motor vehicle emissions, by approximately 24% and 13%, respectively. The effects were larger for areas of high population density and areas near major roads. We also find that the reductions got smaller, and air pollution gradually approached normal levels, after the orders were lifted. This suggests that the air quality improvements were temporary.

4.
Int J Biol Macromol ; 219: 672-684, 2022 Oct 31.
Artigo em Inglês | MEDLINE | ID: mdl-35952815

RESUMO

Cell adhesion has a critical influence on various processes such as cancer metastasis and wound healing. Many substrates have been used for studying cell adhesion and its related biological processes, it is still highly desirable to have a simply prepared and low-cost substrate suitable for regulating cell adhesion. In this study, we produced a series of polyvinyl alcohol/gelatin hydrogels with different gelatin concentrations via dry-annealing method. Our data showed that the protein adsorbing capability was enhanced and cell adhesion area and the ratio of non-spherical cells were increased with the increment of gelatin concentration. We also observed that varying cell adhesion conditions induced by polyvinyl alcohol /gelatin hydrogels resulted in expression level changes of genes involved in mechanotransduction from extracellular matrices (ECM) to the nucleus. In particular, we detected a widespread increase in chromatin accessibility under poor cell adhesion condition. This work provides a useful hydrogel system for regulating cell adhesion and opens up new possibilities for the design of biomaterials for cell adhesion study.


Assuntos
Gelatina , Álcool de Polivinil , Materiais Biocompatíveis , Adesão Celular , Cromatina/genética , Gelatina/farmacologia , Hidrogéis/farmacologia , Mecanotransdução Celular , Álcool de Polivinil/farmacologia
5.
Front Cell Dev Biol ; 9: 664545, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34307349

RESUMO

It has been previously demonstrated that uniaxial cyclic stretching (UCS) induces differentiation of mesenchymal stem cells (MSCs) into osteoblasts in vitro. It is also known that interactions between cells and external forces occur at various aspects including cell-matrix, cytoskeleton, nucleus membrane, and chromatin. However, changes in chromatin landscape during this process are still not clear. The present study was aimed to determine changes of chromatin accessibility under cyclic stretch. The influence of cyclic stretching on the morphology, proliferation, and differentiation of hMSCs was characterized. Changes of open chromatin sites were determined by assay for transposase accessible chromatin with high-throughput sequencing (ATAC-seq). Our results showed that UCS induced cell reorientation and actin stress fibers realignment, and in turn caused nuclear reorientation and deformation. Compared with unstrained group, the expression of osteogenic and chondrogenic marker genes were the highest in group of 1 Hz + 8% strain; this condition also led to lower cell proliferation rate. Furthermore, there were 2022 gene loci with upregulated chromatin accessibility in 1 Hz + 8% groups based on the analysis of chromatin accessibility. These genes are associated with regulation of cell morphogenesis, cell-substrate adhesion, and ossification. Signaling pathways involved in osteogenic differentiation were found in up-regulated GO biological processes. These findings demonstrated that UCS increased the openness of gene loci associated with regulation of cell morphogenesis and osteogenesis as well as the corresponding transcription activities. Moreover, the findings also connect the changes in chromatin accessibility with cell reorientation, nuclear reorientation, and deformation. Our study may provide reference for directed differentiation of stem cells induced by mechanical microenvironments.

6.
Artigo em Inglês | MEDLINE | ID: mdl-28499176

RESUMO

We examine recent work in cognitive neuroscience that investigates brain networks. Brain networks are characterized by the ways in which brain regions are functionally and anatomically connected to one another. Cognitive neuroscientists use various noninvasive techniques (e.g., fMRI) to investigate these networks. They represent them formally as graphs. And they use various graph theoretic techniques to analyze them further. We distinguish between knowledge of the graph theoretic structure of such networks (structural knowledge) and knowledge of what instantiates that structure (nonstructural knowledge). And we argue that this work provides structural knowledge of brain networks. We explore the significance of this conclusion for the scientific realism debate. We argue that our conclusion should not be understood as an instance of a global structural realist claim regarding the structure of the unobservable part of the world, but instead, as a local structural realist attitude towards brain networks in particular. And we argue that various local approaches to the realism debate, i.e., approaches that restrict realist commitments to particular theories and/or entities, are problematic insofar as they don't allow for the possibility of such a local structural realist attitude.


Assuntos
Encéfalo/anatomia & histologia , Encéfalo/fisiologia , Conhecimento , Humanos , Teste de Realidade
7.
Biomech Model Mechanobiol ; 16(3): 1049-1063, 2017 06.
Artigo em Inglês | MEDLINE | ID: mdl-28093648

RESUMO

Successful tissue engineering and regenerative therapy necessitate having extensive knowledge about mechanical milieu in engineered tissues and the resident cells. In this study, we have merged two powerful analysis tools, namely finite element analysis and stochastic analysis, to understand the mechanical strain within the tissue scaffold and residing cells and to predict the cell viability upon applying mechanical strains. A continuum-based multi-length scale finite element model (FEM) was created to simulate the physiologically relevant equiaxial strain exposure on cell-embedded tissue scaffold and to calculate strain transferred to the tissue scaffold (macro-scale) and residing cells (micro-scale) upon various equiaxial strains. The data from FEM were used to predict cell viability under various equiaxial strain magnitudes using stochastic damage criterion analysis. The model validation was conducted through mechanically straining the cardiomyocyte-encapsulated collagen constructs using a custom-built mechanical loading platform (EQUicycler). FEM quantified the strain gradients over the radial and longitudinal direction of the scaffolds and the cells residing in different areas of interest. With the use of the experimental viability data, stochastic damage criterion, and the average cellular strains obtained from multi-length scale models, cellular viability was predicted and successfully validated. This methodology can provide a great tool to characterize the mechanical stimulation of bioreactors used in tissue engineering applications in providing quantification of mechanical strain and predicting cellular viability variations due to applied mechanical strain.


Assuntos
Sobrevivência Celular/fisiologia , Colágeno/metabolismo , Modelos Biológicos , Miócitos Cardíacos/metabolismo , Estresse Mecânico , Alicerces Teciduais , Animais , Análise de Elementos Finitos , Humanos , Reprodutibilidade dos Testes , Engenharia Tecidual
8.
Acta Crystallogr Sect E Struct Rep Online ; 70(Pt 2): o152, 2014 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-24764874

RESUMO

The mol-ecular structure of the title compound, C4H12N2O4S2, has crystallographic inversion symmetry. The central N-C-C-N moiety was refined as disordered over two sets of sites with an approximate occupancy ratio of 3:1 [0.742 (15):0.258 (15). In the crystal, N-H⋯O hydrogen bonds link adjacent mol-ecules into a thick sheet structure parallel to the b-axis direction.

9.
Pediatr Crit Care Med ; 15(3): e128-41, 2014 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-24413318

RESUMO

OBJECTIVE: The primary objective of this study was to compare and contrast the characteristics and survival outcomes of cardiopulmonary resuscitation for "monitored" events in pediatric patients treated with chest compressions more than or equal to 1 minute in varied ICU settings. DESIGN: Retrospective observational study. SETTING: Three different specialized ICUs in a single, tertiary care, academic children's hospital. PATIENTS: We collected demographic information, preexisting conditions, preevent characteristics, event characteristics, and outcome data. The primary outcome measure was survival to hospital discharge. Secondary outcome measures included return of spontaneous circulation, 24-hour survival, and survival with good neurologic outcome. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Four hundred eleven patients treated with chest compressions for more than or equal to 1 minute were included in the analysis: 170 patients were located in the cardiovascular ICU, 157 patients in the neonatal ICU, and 84 patients in the PICU. Arrest durations were longer in the cardiovascular ICU than other ICUs. Use of extracorporeal cardiopulmonary resuscitation was more prevalent in the cardiovascular ICU (cardiovascular ICU, 17%; neonatal ICU, 3%; PICU, 4%). Return of spontaneous circulation, 24-hour survival, survival to hospital discharge, and good neurologic outcome were highest among neonatal ICU patients (survival to discharge, 53%) followed by cardiovascular ICU patients (survival to discharge, 46%) and PICU patients (survival to discharge, 36%). In a multivariable model controlling for patient and event characteristics, using cardiovascular ICU as reference, adjusted odds of survival in PICU were 0.33 (95% CI, 0.14-0.76; p = 0.009) and odds of survival in neonatal ICU were 0.80 (95% CI, 0.31-2.11; p = 0.65). CONCLUSIONS: Comparative analysis of pediatric patients undergoing cardiopulmonary resuscitation in three different ICU settings demonstrated a significant variation in baseline, preevent, and event characteristics. Although outcomes vary significantly among the three different ICUs, it was difficult to ascertain if this difference was due to variation in the disease process or variation in the location of the patient.


Assuntos
Reanimação Cardiopulmonar/estatística & dados numéricos , Unidades de Terapia Intensiva Pediátrica/estatística & dados numéricos , Alta do Paciente/estatística & dados numéricos , Adolescente , Reanimação Cardiopulmonar/mortalidade , Criança , Pré-Escolar , Feminino , Hospitais Pediátricos , Humanos , Lactente , Recém-Nascido , Masculino , Estudos Retrospectivos , Análise de Sobrevida , Atenção Terciária à Saúde , Resultado do Tratamento
10.
Genome Res ; 24(5): 751-60, 2014 May.
Artigo em Inglês | MEDLINE | ID: mdl-24443471

RESUMO

Thousands of putative enhancers are characterized in the human genome, yet few have been shown to have a functional role in cancer progression. Inhibiting oncokinases, such as EGFR, ALK, ERBB2, and BRAF, is a mainstay of current cancer therapy but is hindered by innate drug resistance mediated by up-regulation of the HGF receptor, MET. The mechanisms mediating such genomic responses to targeted therapy are unknown. Here, we identify lineage-specific enhancers at the MET locus for multiple common tumor types, including a melanoma lineage-specific enhancer 63 kb downstream from the MET TSS. This enhancer displays inducible chromatin looping with the MET promoter to up-regulate MET expression upon BRAF inhibition. Epigenomic analysis demonstrated that the melanocyte-specific transcription factor, MITF, mediates this enhancer function. Targeted genomic deletion (<7 bp) of the MITF motif within the MET enhancer suppressed inducible chromatin looping and innate drug resistance, while maintaining MITF-dependent, inhibitor-induced melanoma cell differentiation. Epigenomic analysis can thus guide functional disruption of regulatory DNA to decouple pro- and anti-oncogenic functions of a dominant transcription factor and block innate resistance to oncokinase therapy.


Assuntos
Resistencia a Medicamentos Antineoplásicos/genética , Elementos Facilitadores Genéticos , Regulação Neoplásica da Expressão Gênica , Genoma Humano , Proteínas Proto-Oncogênicas B-raf/antagonistas & inibidores , Linhagem Celular Tumoral , Cromatina/genética , Cromatina/metabolismo , Humanos , Indóis/farmacologia , Melanoma/genética , Fator de Transcrição Associado à Microftalmia/genética , Fator de Transcrição Associado à Microftalmia/metabolismo , Regiões Promotoras Genéticas , Inibidores de Proteínas Quinases/farmacologia , Proteínas Proto-Oncogênicas B-raf/genética , Proteínas Proto-Oncogênicas B-raf/metabolismo , Proteínas Proto-Oncogênicas c-met/genética , Proteínas Proto-Oncogênicas c-met/metabolismo , Sulfonamidas/farmacologia , Transcriptoma , Vemurafenib
11.
Biofabrication ; 5(4): 045010, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-24280635

RESUMO

Recent development in bioprinting technology enables the fabrication of complex, precisely controlled cell-encapsulated tissue constructs. Bioprinted tissue constructs have potential in both therapeutic applications and nontherapeutic applications such as drug discovery and screening, disease modelling and basic biological studies such as in vitro tissue modelling. The mechanical properties of bioprinted in vitro tissue models play an important role in mimicking in vivo the mechanochemical microenvironment. In this study, we have constructed three-dimensional in vitro soft tissue models with varying structure and porosity based on the 3D cell-assembly technique. Gelatin/alginate hybrid materials were used as the matrix material and cells were embedded. The mechanical properties of these models were assessed via compression tests at various culture times, and applicability of three material constitutive models was examined for fitting the experimental data. An assessment of cell bioactivity in these models was also carried out. The results show that the mechanical properties can be improved through structure design, and the compression modulus and strength decrease with respect to time during the first week of culture. In addition, the experimental data fit well with the Ogden model and experiential function. These results provide a foundation to further study the mechanical properties, structural and combined effects in the design and the fabrication of in vitro soft tissue models.


Assuntos
Bioimpressão/métodos , Técnicas de Cultura de Células/instrumentação , Modelos Biológicos , Alicerces Teciduais , Alginatos , Animais , Fenômenos Biomecânicos , Linhagem Celular , Proliferação de Células , Sobrevivência Celular/fisiologia , Força Compressiva , Módulo de Elasticidade , Gelatina , Ácido Glucurônico , Ácidos Hexurônicos , Camundongos , Engenharia Tecidual
12.
Trends Genet ; 29(1): 31-40, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-23141808

RESUMO

More than 100 human genetic skin diseases, impacting over 20% of the population, are characterized by disrupted epidermal differentiation. A significant proportion of the 90 genes identified in these disorders to date are concentrated within several functional pathways, suggesting the emergence of organizing themes in epidermal differentiation. Among these are the Notch, transforming growth factor ß (TGFß), IκB kinase (IKK), Ras/mitogen-activated protein kinase (MAPK), phosphoinositide 3-kinase (PI3K), p63, and Wnt signaling pathways, as well as core biological processes mediating calcium homeostasis, tissue integrity, cornification, and lipid biogenesis. Here, we review recent results supporting the central role of these pathways in epidermal differentiation, highlighting the integration of genetic information with functional studies to illuminate the biological actions of these pathways in humans as well as to guide development of future therapeutics to correct their dysfunction.


Assuntos
Diferenciação Celular/genética , Epiderme/fisiologia , Transdução de Sinais/genética , Dermatopatias/genética , Dermatopatias/fisiopatologia , Animais , Epiderme/metabolismo , Redes Reguladoras de Genes/fisiologia , Humanos , Modelos Biológicos , Dermatopatias/etiologia
13.
ASAIO J ; 59(1): 52-6, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23232182

RESUMO

Our objective was to evaluate morbidity and mortality associated with extracorporeal membrane oxygenation (ECMO) in children with genetic syndromes and heart disease. We conducted a retrospective review of all children with heart disease and genetic syndromes receiving ECMO during the period January 2000 and March 2012 at Arkansas Children's Hospital, Little Rock. The medical charts were reviewed to obtain the following variables: demographic information, medical and surgical history, laboratory and microbiological, information on organ dysfunction, and outcome characteristics. The outcome variables evaluated in this report included: hospital length of stay (LOS), survival to hospital discharge, and current survival. Outcome data were compared among critically ill children with and without syndromes. During the study period, there were 377 ECMO runs in 336 children with heart disease. Of these, 43 ECMO runs occurred in children with genetic syndromes whereas 334 ECMO runs occurred in children with no genetic abnormality. Children in the group with underlying genetic syndrome were older at the time of ECMO cannulation than the group with no syndrome. During the ECMO run, hospital LOS and mortality were similar in children with and without underlying genetic abnormality. Among genetically abnormal patients, renal insufficiency and need for dialysis were associated with mortality. In this group, 24 patients (56%) were discharged alive. However, only 10 patients are living to date in this cohort. ECMO can be used in children with heart disease and genetic syndromes with good results. The survival rate is high and the complication rate is low.


Assuntos
Oxigenação por Membrana Extracorpórea , Doenças Genéticas Inatas/complicações , Doenças Genéticas Inatas/terapia , Cardiopatias/complicações , Cardiopatias/terapia , Arkansas/epidemiologia , Contraindicações , Síndrome de Down/complicações , Síndrome de Down/mortalidade , Síndrome de Down/terapia , Oxigenação por Membrana Extracorpórea/efeitos adversos , Oxigenação por Membrana Extracorpórea/mortalidade , Feminino , Doenças Genéticas Inatas/mortalidade , Cardiopatias/mortalidade , Humanos , Lactente , Recém-Nascido , Masculino , Estudos Retrospectivos , Síndrome
14.
Am J Hum Genet ; 91(3): 435-43, 2012 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-22922031

RESUMO

The basis for impaired differentiation in TP63 mutant ankyloblepharon-ectodermal dysplasia-clefting (AEC) syndrome is unknown. Human epidermis harboring AEC TP63 mutants recapitulated this impairment, along with downregulation of differentiation activators, including HOPX, GRHL3, KLF4, PRDM1, and ZNF750. Gene-set enrichment analysis indicated that disrupted expression of epidermal differentiation programs under the control of ZNF750 and KLF4 accounted for the majority of disrupted epidermal differentiation resulting from AEC mutant TP63. Chromatin immunoprecipitation (ChIP) analysis and ChIP-sequencing of TP63 binding in differentiated keratinocytes revealed ZNF750 as a direct target of wild-type and AEC mutant TP63. Restoring ZNF750 to AEC model tissue rescued activator expression and differentiation, indicating that AEC TP63-mediated ZNF750 inhibition contributes to differentiation defects in AEC. Incorporating disease-causing mutants into regenerated human tissue can thus dissect pathomechanisms and identify targets that reverse disease features.


Assuntos
Fenda Labial/genética , Fissura Palatina/genética , Displasia Ectodérmica/genética , Anormalidades do Olho/genética , Fatores de Transcrição/genética , Proteínas Supressoras de Tumor/genética , Diferenciação Celular/genética , Epiderme/metabolismo , Pálpebras/anormalidades , Humanos , Fator 4 Semelhante a Kruppel , Mutação , Técnicas de Cultura de Órgãos/métodos , Transcriptoma
15.
BMC Syst Biol ; 5: 88, 2011 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-21624115

RESUMO

BACKGROUND: Cells constantly sense many internal and environmental signals and respond through their complex signaling network, leading to particular biological outcomes. However, a systematic characterization and optimization of multi-signal responses remains a pressing challenge to traditional experimental approaches due to the arising complexity associated with the increasing number of signals and their intensities. RESULTS: We established and validated a data-driven mathematical approach to systematically characterize signal-response relationships. Our results demonstrate how mathematical learning algorithms can enable systematic characterization of multi-signal induced biological activities. The proposed approach enables identification of input combinations that can result in desired biological responses. In retrospect, the results show that, unlike a single drug, a properly chosen combination of drugs can lead to a significant difference in the responses of different cell types, increasing the differential targeting of certain combinations. The successful validation of identified combinations demonstrates the power of this approach. Moreover, the approach enables examining the efficacy of all lower order mixtures of the tested signals. The approach also enables identification of system-level signaling interactions between the applied signals. Many of the signaling interactions identified were consistent with the literature, and other unknown interactions emerged. CONCLUSIONS: This approach can facilitate development of systems biology and optimal drug combination therapies for cancer and other diseases and for understanding key interactions within the cellular network upon treatment with multiple signals.


Assuntos
Biologia de Sistemas/métodos , Algoritmos , Linhagem Celular Tumoral , Biologia Computacional/métodos , Ensaios de Seleção de Medicamentos Antitumorais/métodos , Regulação Neoplásica da Expressão Gênica , Humanos , Modelos Biológicos , Modelos Teóricos , Neoplasias/tratamento farmacológico , Transdução de Sinais , Software
16.
Neuroimage ; 54 Suppl 1: S30-6, 2011 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-20547228

RESUMO

In this paper, we show that bone piezoelectricity-a phenomenon in which bone polarizes electrically in response to an applied mechanical stress and produces a short-range electric field-may be a source of intense blast-induced electric fields in the brain, with magnitudes and timescales comparable to fields with known neurological effects. We compute the induced charge density in the skull from stress data on the skull from a finite-element full-head model simulation of a typical IED-scale blast wave incident on an unhelmeted human head as well as a human head protected by a kevlar helmet, and estimate the resulting electric fields in the brain in both cases to be on the order of 10 V/m in millisecond pulses. These fields are more than 10 times stronger than the IEEE safety guidelines for controlled environments (IEEE Standards Coordinating Committee 28, 2002) and comparable in strength and timescale to fields from repetitive Transcranial Magnetic Stimulation (rTMS) that are designed to induce neurological effects (Wagner et al., 2006a). They can be easily measured by RF antennas, and may provide the means to design a diagnostic tool that records a quantitative measure of the head's exposure to blast insult.


Assuntos
Traumatismos por Explosões/fisiopatologia , Lesões Encefálicas/fisiopatologia , Campos Eletromagnéticos , Modelos Neurológicos , Crânio/fisiopatologia , Fenômenos Biofísicos , Encéfalo/fisiopatologia , Análise de Elementos Finitos , Humanos , Estresse Mecânico
17.
J Biomech ; 43(6): 1031-8, 2010 Apr 19.
Artigo em Inglês | MEDLINE | ID: mdl-20096842

RESUMO

One of the major challenges in scaffold guided regenerative therapies is identifying the essential cues such as mechanical forces that induce cellular responses to form functional tissue. Developing multi-scale modelling methods would facilitate in predicting responses of encapsulated cells for controlling and maintaining the cell phenotype in an engineered tissue construct, when mechanical loads are applied. The objective of this study is to develop a 3D multi-scale numerical model for analyzing the stresses and deformations of the cell when the tissue construct is subjected to macro-scale mechanical loads and to predict load-induced cell damage. Specifically, this methodology characterizes the macro-scale structural behavior of the scaffold, and quantifies 3D stresses and deformations of the cells at the micro-scale and at a cellular level, wherein individual cell components are incorporated. Assuming that cells have inherent ability to sustain a critical load without damage, a damage criterion is established and a stochastic simulation is employed to predict the percentage cell viability within the tissue constructs. Bio-printed cell-alginate tissue constructs were tested with 1%, 5% and 10% compression strain applied and the cell viability were characterized experimentally as 23.2+/-16.8%, 9.0+/-5.4% and 4.6+/-2.1%. Using the developed method, the corresponding micro-environments of the cells were analyzed, the mean critical compressive strain was determined as 0.5%, and the cell viability was predicted as 26.6+/-7.0, 13.3+/-4.5, and 10.1+/-2.8. The predicted results capture the trend of the damage observed from the experimental study.


Assuntos
Modelos Biológicos , Engenharia Tecidual , Alginatos , Animais , Fenômenos Biomecânicos , Sobrevivência Celular , Força Compressiva , Células Endoteliais/fisiologia , Análise de Elementos Finitos , Ácido Glucurônico , Ácidos Hexurônicos , Ratos , Alicerces Teciduais
18.
BMC Cancer ; 9: 259, 2009 Jul 29.
Artigo em Inglês | MEDLINE | ID: mdl-19640308

RESUMO

BACKGROUND: Breast cancer is a major problem in the United States leading to tens of thousands of deaths each year. Although citrus auraptene suppresses cancer in numerous rodent models, its role in breast cancer prevention previously has not been reported. Thus, our goal was to determine the anticarcinogenic effects of auraptene against breast cancer. METHODS: The effects of auraptene on cell proliferation of MCF-7 and MDA-MB-231 human breast carcinoma cells in culture was assessed by measuring metabolism of a substrate to a formazan dye. Dietary effects of auraptene on tumor incidence, multiplicity and latency were studied in the N-methyl nitrosourea (MNU) induced mammary carcinogenesis model in female Sprague Dawley rats. The concentration of auraptene in rat tissues was analyzed by reverse phase HPLC. Cyclin D1 expression in MCF-7 cells and rat tumors was measured by western blot. RESULTS: Auraptene (500 ppm) significantly delayed median time to tumor by 39 days compared to the MNU only group (p < 0.05, n = 24-26). Auraptene (10 microM) reduced Insulin like Growth Factor-1 (IGF-1, 10 ng/mL)-induced cyclin D1 expression by 40% in MCF-7 cells. In comparison, western blot analysis of rat mammary tumors (n = 10 per group) confirmed that auraptene (500 ppm) significantly reduced (p < 0.05) cyclin D1 expression by 49% compared to the MNU only group. Analysis of rat mammary tissue extract by HPLC with fluorescence detection indicated an average concentration (means +/- S.E.) of 1.4 +/- 0.5 microM and 1.8 +/- 0.3 microM in the normal mammary glands of the auraptene 200 ppm and 500 ppm groups, respectively. The concentration (means +/- S.E.) of auraptene in the mammary tumors of the auraptene 200 ppm group was 0.31 +/- 0.98 microM. CONCLUSION: Overall, these observations suggest that the predominant effect of auraptene was to delay the development of tumors possibly through the suppression of cyclin D1 expression. These results point to the potential chemopreventive effects of auraptene in mammary carcinogenesis.


Assuntos
Citrus/metabolismo , Cumarínicos/farmacologia , Ciclina D1/biossíntese , Metilnitrosoureia/farmacologia , Animais , Anticarcinógenos/farmacologia , Linhagem Celular Tumoral , Proliferação de Células , Cromatografia Líquida de Alta Pressão , Corantes/farmacologia , Feminino , Formazans/farmacologia , Humanos , Ratos , Ratos Sprague-Dawley
19.
Biotechnol J ; 4(8): 1168-77, 2009 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-19507149

RESUMO

Bioprinting is an emerging technology in the field of tissue engineering and regenerative medicine. The process consists of simultaneous deposition of cells, biomaterial and/or growth factors under pressure through a micro-scale nozzle. Cell viability can be controlled by varying the parameters like pressure and nozzle diameter. The process itself can be a very useful tool for evaluating an in vitro cell injury model. It is essential to understand the cell responses to process-induced mechanical disturbances because they alter cell morphology and function. We carried out analysis and quantification of the degree of cell injury induced by bioprinting process. A parametric study with different process parameters was conducted to analyze and quantify cell injury as well as to optimize the parameters for printing viable cells. A phenomenological model was developed correlating the percentage of live, apoptotic and necrotic cells to the process parameters. This study incorporates an analytical formulation to predict the cell viability through the system as a function of the maximum shear stress in the system. The study shows that dispensing pressure has a more significant effect on cell viability than the nozzle diameter. The percentage of live cells is reduced significantly (by 38.75%) when constructs are printed at 40 psi compared to those printed at 5 psi.


Assuntos
Biotecnologia/métodos , Medula Suprarrenal/citologia , Animais , Apoptose , Materiais Biocompatíveis/química , Linhagem Celular , Sobrevivência Celular , Desenho de Equipamento , Peptídeos e Proteínas de Sinalização Intercelular/metabolismo , Modelos Estatísticos , Necrose , Ratos , Medicina Regenerativa/métodos , Estresse Mecânico , Engenharia Tecidual/métodos
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...