Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 27
Filtrar
1.
IISE Trans ; 52(8): 832-849, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33043230

RESUMO

This research creates an operations engineering and management methodology to optimize a complex operational planning and coordination challenge faced by sites that perform clinical research trials. The time-sensitive and resource-specific treatment sequences for each of the many trial protocols conducted at a site make it very difficult to capture the dynamics of this unusually complex system. Existing approaches for site planning and participant scheduling exhibit both excessively long and highly variable Time to First Available Visit (TFAV) waiting times and high staff overtime costs. We have created a new method, termed CApacity Planning Tool And INformatics (CAPTAIN) that provides decision support to identify the most valuable set of research trials to conduct within available resources and a plan for how to book their participants. Constraints include (i) the staff overtime costs, and/or (ii) the TFAV by trial. To estimate the site's metrics via a Mixed Integer Program, CAPTAIN combines a participant trajectory forecasting with an efficient visit booking reservation plan to allocate the date for the first visit of every participant's treatment sequence. It also plans a daily nursing staff schedule that is optimized together with the booking reservation plan to optimize each nurse's shift assignments in consideration of participants' requirements/needs.

2.
Vasc Med ; 21(1): 21-32, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26584888

RESUMO

UNLABELLED: Alternative treatment strategies for claudication are needed and cell-based therapies designed to induce angiogenesis are promising. The purpose of this report was to conduct a Phase I safety, dose-escalating, non-randomized, open-label study of autologous, fully differentiated venous endothelial and smooth muscle cells called MultiGeneAngio (MGA) for claudication due to peripheral artery disease. Twelve subjects, at two centers, received a single intra-arterial infusion of a suspension of equal amounts of transduced autologous venous smooth muscle cells expressing vascular endothelial growth factor (VEGF165) and endothelial cells expressing angiopoietin-1 (Ang-1) (Cohort 1: 1 × 10(7), Cohort 2: 2 × 10(7), Cohort 3: 5 × 10(7), Cohort 4: 7 × 10(7)). The treatment was given unblinded and in the more symptomatic lower extremity. Transduced cells were tested for in vitro doubling time, telomerase activity, and gene expression. The main outcomes were clinical safety and tolerability. Other safety measures included ankle-brachial index (ABI) and walking time on a treadmill. All subjects were male (mean age 60 ± 5 years) including 25% with diabetes mellitus. At 1-year follow-up, there was one serious adverse event possibly related to MGA. Safety endpoints including VEGF and Ang-1 plasma protein levels were within normal ranges in all subjects. The mean maximal walking time increased from baseline to 1 year and the index limb ABI was unchanged, indicating no safety concerns. MGA, an autologous, transduced, cell-based therapy was well tolerated and safe in this Phase I study. Further evaluation is warranted in randomized human studies. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT00390767.


Assuntos
Proteínas Angiogênicas/biossíntese , Transplante de Células/métodos , Células Endoteliais/transplante , Terapia Genética/métodos , Claudicação Intermitente/cirurgia , Miócitos de Músculo Liso/transplante , Neovascularização Fisiológica , Doença Arterial Periférica/cirurgia , Idoso , Proteínas Angiogênicas/genética , Angiopoietina-1/biossíntese , Angiopoietina-1/genética , Índice Tornozelo-Braço , Proliferação de Células , Células Cultivadas , Células Endoteliais/metabolismo , Teste de Esforço , Tolerância ao Exercício , Humanos , Claudicação Intermitente/diagnóstico , Claudicação Intermitente/genética , Claudicação Intermitente/metabolismo , Claudicação Intermitente/fisiopatologia , Masculino , Michigan , Pessoa de Meia-Idade , Miócitos de Músculo Liso/metabolismo , Pennsylvania , Doença Arterial Periférica/diagnóstico , Doença Arterial Periférica/genética , Doença Arterial Periférica/metabolismo , Doença Arterial Periférica/fisiopatologia , Recuperação de Função Fisiológica , Telomerase/metabolismo , Fatores de Tempo , Transdução Genética , Resultado do Tratamento , Fator A de Crescimento do Endotélio Vascular/biossíntese , Fator A de Crescimento do Endotélio Vascular/genética
3.
J Empir Res Hum Res Ethics ; 10(1): 37-48, 2015 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-25742665

RESUMO

In this article, we report on an effort to study the development and usefulness of a large, broad-use, opt-in biorepository for genomic research, focusing on three ethical issues: providing appropriate understanding, recruiting in ways that do not comprise autonomous decisions, and assessing costs versus benefits. We conclude the following: (a) Understanding can be improved by separating the task of informing subjects from documenting informed consent (Common Rule) and permission to use personal health information and samples for research (Health Insurance Portability and Accountability Act [HIPAA]); however, regulations might have to be changed to accommodate this approach. (b) Changing recruiting methods increases efficiency but can interfere with subject autonomy. (c) Finally, we propose a framework for the objective evaluation of the utility of biorepositories and suggest that more attention needs to be paid to use and sustainability.


Assuntos
Bancos de Espécimes Biológicos/ética , Pesquisa Biomédica/ética , Genômica/ética , Registros de Saúde Pessoal/ética , Consentimento Livre e Esclarecido/ética , Seleção de Pacientes , Sujeitos da Pesquisa , Compreensão , Termos de Consentimento , Análise Custo-Benefício , DNA , Genoma , Health Insurance Portability and Accountability Act , Humanos , Autonomia Pessoal , Estados Unidos
4.
Analyst ; 139(11): 2734-41, 2014 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-24757707

RESUMO

Sessile drop formation, also called drop deposition, has been studied as a potential medical diagnostic, but the effects of complex biofluid rheology on the final deposition pattern are not well understood. We studied two model biofluids, blood plasma and synovial fluid, when deposited onto slightly hydrophilic substrates forming a contact angle of 50-90°. Drops were imaged during the evaporation process and geometric properties of the drop, such as contact angle and drop height, were calculated from the images. The resulting dried biofluid drops were then examined using light microscopy and Raman spectroscopy to assess morphological and chemical composition of the dried drop. The effect of substrate contact angle (surface wetting) and fluid concentration was examined. We found that when biofluids are deposited onto slightly hydrophilic surfaces, with a contact angle of 50-90°, a ring-shaped deposit was formed. Analysis of the drying drop's geometric properties indicates that biofluid dynamics follow the piling model of drop formation, as proposed by Deegan et al. The final deposition pattern varied with substrate surface and concentration, as shown by light microscopy photos of dried drops. The chemical composition of the outer ring was minimally affected by substrate surface, but the spatial heterogeneity of protein distribution within the ring varied with concentration. These results indicate that biofluid drop deposition produces ring-shaped deposits which can be examined by multiple analytical techniques.


Assuntos
Líquidos Corporais/química , Microscopia/métodos , Análise Espectral Raman
5.
Diabetes Care ; 36(11): 3652-4, 2013 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-23920085

RESUMO

OBJECTIVE: Osteomyelitis in the diabetic foot is a major risk factor for amputation, but there is a limited understanding of early-stage infection, impeding limb-preserving diagnoses. We hypothesized that bone composition measurements provide insight into the early pathophysiology of diabetic osteomyelitis. RESEARCH DESIGN AND METHODS: Compositional analysis by Raman spectroscopy was performed on bone specimens from patients with a clinical diagnosis of osteomyelitis in the foot requiring surgical intervention as either a biopsy (n = 6) or an amputation (n = 11). RESULTS: An unexpected result was the discovery of pathological calcium phosphate minerals in addition to normal bone mineral. Dicalcium phosphate dihydrate, also called brushite, and uncarbonated apatite were found to be exclusively associated with infected bone. CONCLUSIONS: Compositional measurements provided a unique insight into the pathophysiology of osteomyelitis in diabetic foot ulcers. At-patient identification of pathological minerals by Raman spectroscopy may serve as an early-stage diagnostic approach.


Assuntos
Densidade Óssea , Pé Diabético/complicações , Pé Diabético/cirurgia , Osteomielite/diagnóstico , Adulto , Idoso , Idoso de 80 Anos ou mais , Amputação Cirúrgica , Pé Diabético/patologia , Diagnóstico Precoce , Feminino , Pé/cirurgia , Humanos , Masculino , Pessoa de Meia-Idade , Osteomielite/etiologia , Osteomielite/patologia , Análise Espectral Raman
6.
J R Soc Interface ; 10(86): 20130464, 2013 Sep 06.
Artigo em Inglês | MEDLINE | ID: mdl-23825118

RESUMO

Monitoring extracellular matrix (ECM) components is one of the key methods used to determine tissue quality in three-dimensional scaffolds for regenerative medicine and clinical purposes. Raman spectroscopy can be used for non-invasive sensing of cellular and ECM biochemistry. We have investigated the use of conventional (confocal and semiconfocal) Raman microspectroscopy and fibre-optic Raman spectroscopy for in vitro monitoring of ECM formation in three-dimensional poly(ethylene oxide terephthalate)-poly(butylene terephthalate) (PEOT/PBT) scaffolds. Chondrocyte-seeded PEOT/PBT scaffolds were analysed for ECM formation by Raman microspectroscopy, biochemical analysis, histology and scanning electron microscopy. ECM deposition in these scaffolds was successfully detected by biochemical and histological analysis and by label-free non-destructive Raman microspectroscopy. In the spectra collected by the conventional Raman set-ups, the Raman bands at 937 and at 1062 cm(-1) which, respectively, correspond to collagen and sulfated glycosaminoglycans could be used as Raman markers for ECM formation in scaffolds. Collagen synthesis was found to be different in single chondrocyte-seeded scaffolds when compared with microaggregate-seeded samples. Normalized band-area ratios for collagen content of single cell-seeded samples gradually decreased during a 21-day culture period, whereas collagen content of the microaggregate-seeded samples significantly increased during this period. Moreover, a fibre-optic Raman set-up allowed for the collection of Raman spectra from multiple pores inside scaffolds in parallel. These fibre-optic measurements could give a representative average of the ECM Raman signal present in tissue-engineered constructs. Results in this study provide proof-of-principle that Raman microspectroscopy is a promising non-invasive tool to monitor ECM production and remodelling in three-dimensional porous cartilage tissue-engineered constructs.


Assuntos
Condrócitos/metabolismo , Matriz Extracelular/metabolismo , Poliésteres/química , Polietilenoglicóis/química , Alicerces Teciduais/química , Animais , Bovinos , Técnicas de Cultura de Células , Células Cultivadas , Condrócitos/ultraestrutura , Colágeno/biossíntese , Matriz Extracelular/ultraestrutura , Glicosaminoglicanos/biossíntese , Microscopia Eletrônica de Varredura , Porosidade , Análise Espectral Raman , Fatores de Tempo
7.
J Biomed Opt ; 18(5): 57002, 2013 May.
Artigo em Inglês | MEDLINE | ID: mdl-23640079

RESUMO

We report an overlooked source of artifacts for clinical specimens, where unexpected and normally negligible contaminants can skew the interpretation of results. During an ongoing study of bone fragments from diabetic osteomyelitis, strong Raman signatures were found, which did not correspond with normal bone mineral or matrix. In a bone biopsy from the calcaneus of a patient affected by diabetic osteomyelitis, Raman microspectroscopic analysis revealed regions with both abnormal mineral and degraded collagen in addition to normal bone. Additional bands indicated a pathological material. Stenotrophomonas maltophilia was identified in the wound culture by independent microbiologic examination. We initially assigned the unusual bands to xanthomonadin, a bacterial pigment from S. maltophilia. However, the same bands were also found more than a year later on a second specimen that had been noticeably contaminated with pathology marking dye. Drop deposition/Raman spectroscopy of commonly used pathology dyes revealed that a blue tissue-marking dye was responsible for the unusual bands in both specimens, even in the first specimen where there was no visible evidence of contamination.


Assuntos
Artefatos , Osso e Ossos/química , Corantes/química , Histocitoquímica/métodos , Análise Espectral Raman/métodos , Osso e Ossos/microbiologia , Osso e Ossos/patologia , Histocitoquímica/normas , Humanos , Osteomielite/patologia , Análise Espectral Raman/normas , Stenotrophomonas maltophilia/isolamento & purificação
8.
J Arthroplasty ; 28(8): 1421-9, 2013 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-23523501

RESUMO

A novel, nonresorbable, monolithic composite structure ceramic, developed using a partially stabilized zirconia ceramic common to implantable devices, was used in a cementless weight-bearing articular implant to test the feasibility of replacing a region of degenerated or damaged articular cartilage in the knee as part of a preclinical study using male mongrel dogs lasting up to 24 weeks. Gross/histological cartilage observations showed no differences among control, 12-week and 24-week groups, while pull-out tests showed an increase in maximum pull-out load over time relative to controls. Hence, the use of a novel ceramic implant as a replacement for a focal cartilage defect leads to effective implant fixation within 12 weeks and does not cause significant degradation in opposing articular cartilage in the time frame evaluated.


Assuntos
Doenças das Cartilagens/cirurgia , Cartilagem Articular/cirurgia , Fêmur/cirurgia , Hemiartroplastia/instrumentação , Prótese Articular , Articulação do Joelho/cirurgia , Animais , Fenômenos Biomecânicos , Doenças das Cartilagens/diagnóstico por imagem , Cartilagem Articular/diagnóstico por imagem , Cerâmica , Modelos Animais de Doenças , Cães , Fêmur/diagnóstico por imagem , Hemiartroplastia/métodos , Articulação do Joelho/diagnóstico por imagem , Masculino , Teste de Materiais , Radiografia , Resultado do Tratamento , Zircônio
11.
Analyst ; 136(21): 4437-46, 2011 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-21912794

RESUMO

To support the translation of Raman spectroscopy into clinical applications, synthetic models are needed to accurately test, optimize and validate prototype fiber optic instrumentation. Synthetic models (also called tissue phantoms) are widely used for developing and testing optical instrumentation for diffuse reflectance, fluorescence, and Raman spectroscopies. While existing tissue phantoms accurately model tissue optical scattering and absorption, they do not typically model the anatomic shapes and chemical composition of tissue. Because Raman spectroscopy is sensitive to molecular composition, Raman tissue phantoms should also approximate the bulk tissue composition. We describe the fabrication and characterization of tissue phantoms for Raman tomography and spectroscopy. These phantoms have controlled chemical and optical properties, and also multilayer morphologies which approximate the appropriate anatomic shapes. Tissue phantoms were fabricated to support on-going Raman studies by simulating the human wrist and rat leg. Surface meshes (triangle patch models) were generated from computed tomography (CT) images of a human arm and rat leg. Rapid prototyping was used to print mold templates with complex geometric patterns. Plastic casting techniques used for movie special effects were adapted to fabricate molds from the rapid prototypes, and finally to cast multilayer gelatin tissue phantoms. The gelatin base was enriched with additives to model the approximate chemistry and optical properties of individual tissue layers. Additional studies were performed to determine optimal casting conditions, phantom stability, layer delamination and chemical diffusion between layers. Recovery of diffuse reflectance and Raman spectra in tissue phantoms varied with probe placement. These phantoms enable optimization of probe placement for human or rat studies. These multilayer tissue phantoms with complex geometries are shown to be stable, with minimal layer delamination and chemical diffusion.


Assuntos
Modelos Anatômicos , Imagens de Fantasmas , Análise Espectral Raman/métodos , Tomografia Computadorizada por Raios X/métodos , Animais , Simulação por Computador , Tecnologia de Fibra Óptica , Humanos , Perna (Membro)/anatomia & histologia , Ratos , Análise Espectral Raman/instrumentação , Punho/anatomia & histologia
12.
Analyst ; 136(8): 1675-85, 2011 Apr 21.
Artigo em Inglês | MEDLINE | ID: mdl-21359366

RESUMO

In this study, we report adaptation of Raman spectroscopy for arthroscopy of joint tissues using a custom-built fiber-optic probe. Differentiation of healthy and damaged tissue or examination of subsurface tissue, such as subchondral bone, is a challenge in arthroscopy because visual inspection may not provide sufficient contrast. Discrimination of healthy versus damaged tissue may be improved by incorporating point spectroscopy or hyperspectral imaging into arthroscopy where the contrast is based on the molecular structure or chemical composition. Articular joint surfaces of knee cadaveric human tissue and tissue phantoms were examined using a custom-designed Raman fiber-optic probe. Fiber-optic Raman spectra were compared against reference spectra of cartilage, subchondral bone and cancellous bone collected using Raman microspectroscopy. In fiber-optic Raman spectra of the articular surface, there was an effect of cartilage thickness on recovery of signal from subchondral bone. At sites with intact cartilage, the bone mineralization ratio decreased but there was a minimal effect in the bone mineral chemistry ratios. Tissue phantoms were prepared as experimental models of the osteochondral interface. Raman spectra of tissue phantoms suggested that optical scattering of cartilage has a large effect on the relative cartilage and bone signal. Finite element analysis modeling of light fluence in the osteochondral interface confirmed experimental findings in human cadaveric tissue and tissue phantoms. These first studies demonstrate the proof of principle for Raman arthroscopic measurement of joint tissues and provide a basis for future clinical or animal model studies.


Assuntos
Articulação do Joelho/anatomia & histologia , Análise Espectral Raman/métodos , Cadáver , Cartilagem Articular/anatomia & histologia , Tecnologia de Fibra Óptica , Humanos
13.
J Biomed Opt ; 14(3): 034013, 2009.
Artigo em Inglês | MEDLINE | ID: mdl-19566306

RESUMO

For many years, viscosity has been the primary method used by researchers in rheumatology to assess the physiochemical properties of synovial fluid in both normal and osteoarthritic patients. However, progress has been limited by the lack of methods that provide multiple layers of information, use small sample volumes, and are rapid. Raman spectroscopy was used to assess the biochemical composition of synovial fluid collected from 40 patients with clinical evidence of knee osteoarthritis (OA) at the time of elective surgical treatment. Severity of knee osteoarthritis was assessed by a radiologist using Kellgren/Lawrence (K/L) scores from knee joint x rays, while light microscopy and Raman spectroscopy were used to examine synovial fluid (SF) aspirates (2 to 10 microL), deposited on fused silica slides. We show that Raman bands used to describe protein secondary structure and content can be used to detect changes in synovial fluid from osteoarthritic patients. Several Raman band intensity ratios increased significantly in spectra collected from synovial fluid in patients with radiological evidence of moderate-to-severe osteoarthritis damage. These ratios can be used to provide a "yes/no" damage assessment. These studies provide evidence that Raman spectroscopy would be a suitable candidate in the evaluation of joint damage in knee osteoarthritis patients.


Assuntos
Osteoartrite do Joelho/diagnóstico , Análise Espectral Raman/métodos , Líquido Sinovial/química , Adulto , Análise de Variância , Análise por Conglomerados , Feminino , Humanos , Masculino , Microscopia/métodos , Pessoa de Meia-Idade , Osteoartrite do Joelho/diagnóstico por imagem , Radiografia
14.
J Immunother ; 31(6): 591-8, 2008.
Artigo em Inglês | MEDLINE | ID: mdl-18528294

RESUMO

Twenty-four subjects with metastatic melanoma were treated on a randomized Phase Ib trial evaluating an autologous tumor lysate-pulsed dendritic cell (DC) vaccine with or without interleukin (IL)-2. The vaccine consisted of autologous DCs obtained from peripheral blood mononuclear cells (PBMCs) cultured in granulocyte macrophage-colony stimulating factor and IL-4 then pulsed with autologous tumor cell lysate and keyhole limpet hemocyanin (KLH). The primary end points of the trial were safety and immune response to vaccine. Subjects were randomized to vaccine administered every other week times 3, vaccine x 3 followed by low-dose IL-2, or vaccine x 3 followed by high-dose IL-2. Immune response was monitored pretreatment and at 2 and 4 weeks after the third vaccine administration. Disease evaluation was performed at 4 weeks after the third vaccination. Therapy was well tolerated with no local vaccine toxicity greater than grade 1 in any arm. IL-2 toxicity was as expected without additional toxicity from the addition of IL-2 to vaccine. Immune response defined as delayed-type hypersensitivity, PBMC interferon-gamma enzyme-linked immunosorbent spot, and PBMC proliferation, to both autologous tumor and KLH were detected in all arms. Interferon-gamma enzyme-linked immunosorbent spot response to KLH (7 of 10 patients) and autologous tumor (4 of 10 patients) were also detected in subjects with available vaccine draining lymph node cells. There were no differences in immune response between treatment arms. No clinical responses were seen. Autologous tumor lysate-pulsed DC vaccine with or without IL-2 was well tolerated and immunogenic but failed to induce clinical response in patients with advanced melanoma.


Assuntos
Vacinas Anticâncer/imunologia , Células Dendríticas/imunologia , Interleucina-2/uso terapêutico , Melanoma/terapia , Adulto , Idoso , Vacinas Anticâncer/efeitos adversos , Feminino , Humanos , Hipersensibilidade Tardia/etiologia , Interferon gama/biossíntese , Masculino , Melanoma/imunologia , Melanoma/secundário , Pessoa de Meia-Idade , Vacinação
15.
Appl Spectrosc ; 62(5): 503-11, 2008 May.
Artigo em Inglês | MEDLINE | ID: mdl-18498691

RESUMO

Biofluids are complex solutions consisting of small ions and large biopolymers such as DNA, proteins, or proteoglycans. Biopolymers affect fluid properties but their effect on drop deposition has not been examined. Hyaluronic acid (HA), an important component in synovial fluid, was chosen as a model biopolymer, and examined using surface-enhanced Raman spectroscopy (SERS). Nanoliter volumes of HA solutions were dried onto a patterned SERS substrate and spectra were collected from the dried hyaluronic acid drops with a near-infrared Raman microscope. Characteristic hyaluronic acid bands were examined. Capillary viscometry measured properties of HA solutions, and entanglement behavior was also modeled using scaling theory principles. Viscosity measurements were incorporated into models of suspended particle droplets to account for the effect of inter-chain attraction on droplet formation. Microscope images were used to evaluate the shape of the dried drop. Relative drop thickness was estimated from concentric rings found at drop edges using established models of light interference by thin films. We found SERS spectra were sensitive not only to polymer conformation, but also to type of deposition (ring versus uniform), and the thickness of the resulting deposition. These data suggest an approach to elucidate the effects of biopolymers and dehydrated biofluids on SERS analysis.


Assuntos
Biopolímeros/química , Ação Capilar , DNA/química , Dessecação , Ácido Hialurônico/química , Conformação Molecular , Proteínas/química , Proteoglicanas/química , Soluções , Análise Espectral Raman , Viscosidade
16.
J Biomed Opt ; 13(1): 011005, 2008.
Artigo em Inglês | MEDLINE | ID: mdl-18315354

RESUMO

Laser-based photoacoustic tomography (PAT), a novel, nonionizing, noninvasive, laser-based technology, has been adapted to the diagnosis and imaging of inflammatory arthritis. A commonly used adjuvant induced arthritis model using carrageenan was employed to simulate acute rheumatoid arthritis in rat tail joints. Cross-sectional photoacoustic images of joints affected by acute inflammation were compared to those of the control. The diameter of the periosteum and the optical absorption of intra-articular tissue were measured on each joint image. Significant differences were found on PAT imaging between the affected joints and the control for both variables measured, including enlarged periosteum diameter and enhanced intra-articular optical absorption occurring in the joints affected with carrageenan-induced arthritis. Anatomical correlation with histological sections of imaged joints and microMRI results verified the findings of PAT. This suggests that PAT has the potential for highly sensitive diagnosis and evaluation of pathologic hallmarks of acute inflammatory arthritis.


Assuntos
Artrite Reumatoide/induzido quimicamente , Artrite Reumatoide/patologia , Carragenina , Modelos Animais de Doenças , Técnicas de Imagem por Elasticidade/métodos , Aumento da Imagem/métodos , Tomografia Óptica/métodos , Animais , Lasers , Ratos , Ratos Sprague-Dawley , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
17.
Mol Pharm ; 4(1): 95-103, 2007.
Artigo em Inglês | MEDLINE | ID: mdl-17274667

RESUMO

Bile acids conjugated to oligoarginine-containing peptides (BACs) form complexes with DNA based on the electrostatic interactions between negatively charged phosphate groups of the nucleic acid and the positively charged side chain guanidinium groups of the oligoarginine in the BACs. Charge neutralization of both components and subsequent increases of the net positive charge of the complex combined with the water-soluble lipophilic nature of the bile acid results in changes in the physicochemistry and biological properties of the complexes. We have examined the relationship of a series of 13 BACs on their interaction with circular plasmid DNA (pDNA). The formation of soluble, low-density and insoluble, high-density complexes was analyzed using several methods. The formation of high-density complexes was dependent on the DNA concentration, and was enhanced by increasing the BAC to pDNA charge ratio. Several of the BAC:pDNA complexes demonstrated exclusion of the DNA-intercalator Hoechst 33258 from pDNA, and were also protected from DNase activity. Several BAC conjugates interacted with pDNA to form nanometer-sized particles suitable for cell transfection in vitro. Five of the 13 BACs were transfection competent as single agents, and 11 of the 13 BACs showed enhancement of transfection in combination with DOPE containing liposomes or silica nanoparticles.


Assuntos
Ácidos e Sais Biliares/metabolismo , DNA Circular/metabolismo , Oligopeptídeos/metabolismo , Transfecção/métodos , Sequência de Aminoácidos , Animais , Ácidos e Sais Biliares/química , Bisbenzimidazol/metabolismo , DNA Circular/ultraestrutura , Desoxirribonucleases/metabolismo , Corantes Fluorescentes/metabolismo , Humanos , Lipossomos/metabolismo , Camundongos , Micelas , Microscopia Eletrônica de Transmissão , Dados de Sequência Molecular , Células NIH 3T3 , Nanopartículas , Nefelometria e Turbidimetria , Oligopeptídeos/síntese química , Oligopeptídeos/química , Tamanho da Partícula , Plasmídeos/metabolismo , Ligação Proteica
18.
J Gene Med ; 8(12): 1379-92, 2006 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-17133338

RESUMO

BACKGROUND AND AIMS: While mature enterocytes are resistant to transduction by adenovirus type 5 (Ad5) vectors, undifferentiated cells are transduced much more efficiently. Our purpose was to study enterocyte transduction in models of intestinal wound healing. METHODS: Transduction was studied ex vivo using cultures of endoscopic biopsies and in vitro utilizing Caco-2 cells in models of mucosal wound healing. Vectors carried either the LacZ or the luciferase gene. CAR (coxsackievirus and adenovirus receptor) and integrins were studied with transduction inhibition and immunofluorescent staining. RESULTS: Increased transduction efficiency was observed for a subset of enterocytes with a flattened de-differentiated phenotype present at the edge of cultured biopsies. In the in vitro systems, expanding Caco-2 cell monolayers exhibited increased transducibility that was time- and dose-dependent, reaching virtually 100% in cells along the leading edge at high viral load. Bioluminescence activity of transduced expanding monolayers was up to 3-fold greater than that of non-expanding monolayers ('fence' system, 48 h, MOI 1000, p < 0.05). Mitomycin C pre-treatment did not affect levels of transduction in expanding monolayers. At the highest viral load tested, CAR or integrin blocking prior to virus application resulted in 39.4% and 45.4% reduction in transduction levels (p < 0.05). Immunofluorescence revealed altered expression of CAR on the migrating edge of the Caco-2 cultures and the expression of CAR on the apical membrane of biopsy enterocytes. CONCLUSIONS: Increased CAR and integrin accessibility in migrating enterocytes mediates increased transduction by Ad5 vectors. This subset of enterocytes provides a target for the delivery of genes of interest for both research and gene therapy applications.


Assuntos
Adenoviridae/classificação , Adenoviridae/genética , Colo/citologia , Vetores Genéticos , Mucosa Intestinal/metabolismo , Transdução Genética , Células CACO-2 , Colo/efeitos dos fármacos , Imunofluorescência , Genes Reporter , Humanos , Mucosa Intestinal/citologia
19.
Appl Spectrosc ; 60(10): 1134-41, 2006 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-17059665

RESUMO

Application of Raman spectroscopy to analysis of subchondral bone is described. The effect of cartilage health on subchondral bone has been widely studied using radiological and histological methods; however, there is no method to directly assay mineral components. We present Raman spectra of femur condyles and observe mineral bands that arise from the subchondral bone. In two separate experiments, transgenic mouse models of early-onset osteoarthritis (OA) and lipoatrophy were compared to tissue from wild-type mice. Raman spectroscopy was used to identify chemical changes in the mineral of subchondral bone that may accompany or precede morphological changes that can be observed by histology. The transgenic mice were compared to age-matched wild-type mice. Subtle alterations in the mineral or collagen matrix were observed by Raman spectroscopy using established Raman markers such as the carbonate-to-phosphate ratio, mineral-to-matrix ratio (MTMR), and amide I ratio. The Raman microscope configuration enabled rapid collection of Raman spectra from the mineralized layer that lies under an intact layer of non-mineralized articular cartilage. The effect of the cartilage layer on collection of spectra is discussed. The technique proposed is capable of providing insight into the chemical changes that occur in subchondral bone on a molecular level.


Assuntos
Densidade Óssea , Fêmur/metabolismo , Articulação do Joelho/metabolismo , Minerais/metabolismo , Osteoartrite do Joelho/metabolismo , Análise Espectral Raman/métodos , Animais , Camundongos
20.
Med Phys ; 33(8): 2691-7, 2006 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-16964846

RESUMO

Photoacoustic tomography (PAT), a nonionizing, noninvasive, laser-based technology was adapted to joint imaging for the first time. Pulsed laser light in the near-infrared region was directed toward a joint with resultant ultrasonic signals recorded and used to reconstruct images that present the optical properties in subsurface joint tissues. The feasibility of this joint imaging system was validated on a Sprague Dawley rat tail model and verified through comparison with histology. With sufficient penetration depth, PAT realized tomographic imaging of a joint as a whole organ noninvasively. Based on the optical contrast, various intra- and extra-articular tissues, including skin, fat, muscle, blood vessels, synovium and bone, were presented successfully in images with satisfactory spatial resolution that was primarily limited by the bandwidth of detected photoacoustic signals rather than optical diffusion as occurs in traditional optical imaging. PAT, with its intrinsic advantages, may provide a unique opportunity to enable the early diagnosis of inflammatory joint disorders, e.g., rheumatoid arthritis, and to monitor therapeutic outcomes with high sensitivity and accuracy.


Assuntos
Acústica , Articulações/citologia , Lasers , Tomografia Óptica/instrumentação , Tomografia Óptica/métodos , Animais , Desenho de Equipamento , Análise de Falha de Equipamento , Técnicas In Vitro , Ratos , Ratos Sprague-Dawley , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA