RESUMO
Scleral defects can result as a consequence of trauma, infectious diseases or cancer and surgical repair with allogeneic scleral grafts can be required. However, this method has limitations and novel alternatives are needed. Here, the efficacy of acellular nanostructured fibrin-agarose hydrogel-based substitutes (NFAH) in the repair of scleral defects in rabbits was studied. For this, scleral defects of 5-mm diameter were made on 18 adult-male New Zealand rabbits and repaired with acellular NFAH, NFAH crosslinked with genipin (NFAH-GP) or glutaraldehyde (NFAH-GA), allogeneic scleral grafts as control (C-CTR) or not repaired (negative control N-CTR) (nâ¯=â¯3 each). Macroscopic and histological analyses were performed after 40-days. Macroscopy confirmed the repair of all defects in a comparable manner than the C-CTR. Histology showed no degradation nor integration in C-CTR while NFAH-GP and NFAH-GA biomaterials were encapsulated by connective and inflammatory tissues with partial biodegradation. The NFAH were fully biodegraded and replaced by a loose connective tissue and sclera covering the defects. This in vivo study demonstrated that the NFAH are a promising biocompatible and pro-regenerative alternative to the use of allogeneic cadaveric grafts. However, large defects and long-term studies are needed to demonstrate the potential clinical usefulness of these substitutes.
Assuntos
Traumatismos Oculares/cirurgia , Adesivo Tecidual de Fibrina/administração & dosagem , Nanoestruturas/uso terapêutico , Esclera/cirurgia , Sefarose/administração & dosagem , Animais , Materiais Biocompatíveis/uso terapêutico , Masculino , Coelhos , Esclera/lesõesRESUMO
Alginate oligosaccharides (AlgO), agarose oligosaccharides (AO), and κ-carrageenan oligosaccharides (KCO) were obtained by specific enzymatic hydrolysis method. The molecular weight distributions of the three oligosaccharides were 1.0â»5.0 kDa, 0.4â»1.4 kDa, and 1.0â»7.0 kDa, respectively. The culture medium was supplemented with the three oligosaccharides and fermented by pig fecal microbiota in vitro, for 24 h. Each oligosaccharide was capable of increasing the concentration of short-chain fatty acids (SCFAs), especially butyric acid, and altering the microbiota composition. Linear discriminant analysis effect size (LEfSe) analysis results showed that the opportunistic pathogenic bacteria Escherichia, Shigella, and Peptoniphilus, were significantly decreased in AlgO supplemented medium. AO could improve the gut microbiota composition by enriching the abundance of Ruminococcaceae, Coprococcus, Roseburia, and Faecalibacterium. Besides, KCO could increase the abundance of SCFA microbial producers and opportunistic pathogenic flora. Therefore, these results indicate that AlgO and AO can be used as gut microbial regulators and can potentially improve animal/human gastrointestinal health and prevent gut disease, whereas the physiological function of KCO needs further evaluation.
Assuntos
Organismos Aquáticos/química , Bactérias/efeitos dos fármacos , Microbioma Gastrointestinal/efeitos dos fármacos , Oligossacarídeos/administração & dosagem , Prebióticos/administração & dosagem , Alginatos/administração & dosagem , Alginatos/química , Alginatos/isolamento & purificação , Animais , Bactérias/isolamento & purificação , Carragenina/administração & dosagem , Carragenina/química , Carragenina/isolamento & purificação , Fezes/microbiologia , Hidrólise , Oligossacarídeos/química , Oligossacarídeos/isolamento & purificação , Phaeophyceae/química , Rodófitas/química , Alga Marinha/química , Sefarose/administração & dosagem , Sefarose/química , Sefarose/isolamento & purificação , SuínosRESUMO
Local and controlled delivery of therapeutic agents directly into focally afflicted tissues is the ideal for the treatment of diseases that require direct interventions. However, current options are obtrusive, difficult to implement, and limited in their scope of utilization; the optimal solution requires a method that may be optimized for available therapies and is designed for exact delivery. To address these needs, we propose the Biocage, a customizable implantable local drug delivery platform. The device is a needle-sized porous container capable of encasing therapeutic molecules and matrices of interest to be eluted into the region of interest over time. The Biocage was fabricated using the Nanoscribe Photonic Professional GT 3D laser lithography system, a two-photon polymerization (2PP) 3D printer capable of micron-level precision on a millimeter scale. We demonstrate the build consistency and features of the fabricated device; its ability to release molecules; and a method for its accurate, stable delivery in mouse brain tissue. The Biocage provides a powerful tool for customizable and precise delivery of therapeutic agents into target tissues.
Assuntos
Sistemas de Liberação de Medicamentos/instrumentação , Sistemas de Liberação de Medicamentos/métodos , Preparações Farmacêuticas/administração & dosagem , Sefarose/administração & dosagem , Animais , Camundongos , Camundongos Endogâmicos C57BL , Impressão TridimensionalRESUMO
Gut microbiota are deeply associated with the prevalence of obesity. Agarose is hydrolyzed easily to yield oligosaccharides, designated as agaro-oligosaccharides (AGO). This study evaluated the effects of AGO on obese phenotype and gut microbial composition in mice. Mice were administered AGO in drinking water (AGO-receiving mice). 16S rRNA gene sequencing analyses revealed their fecal microbiota profiles. Serum bile acids were ascertained using a LC-MS/MS system. Compared to the control group, AGO administration significantly reduced epididymal adipose tissue weights and serum non-esterified fatty acid concentrations, but the cecal content weights were increased. Data from the serum bile acid profile show that concentrations of primary bile acids (cholic acid and chenodeoxycholic acid), but not those of secondary bile acids (deoxycholic acid, lithocholic acid, and ursodeoxycholic acid), tended to increase in AGO-receiving mice. 16S rRNA gene sequencing analyses showed that the relative abundances of 15 taxa differed significantly in AGO-receiving mice. Of these, the relative abundances of Rikenellaceae and Lachnospiraceae were found to be positively correlated with epididymal adipose tissue weight. The relative abundances of Bacteroides and Ruminococcus were correlated negatively with epididymal adipose tissue weight. Although the definitive role of gut microbes of AGO-received mice is still unknown, our data demonstrate the possibility that AGO administration affects the gut microbial composition and inhibits obesity in mice.
Assuntos
Tecido Adiposo/efeitos dos fármacos , Microbioma Gastrointestinal/efeitos dos fármacos , Obesidade/microbiologia , Oligossacarídeos/administração & dosagem , Sefarose/administração & dosagem , Tecido Adiposo/anatomia & histologia , Animais , Bactérias/classificação , Bactérias/efeitos dos fármacos , Bactérias/genética , Carga Bacteriana , Ácidos e Sais Biliares/sangue , Ceco , Ácidos Graxos não Esterificados/sangue , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Tamanho do Órgão , RNA Ribossômico 16S/química , Sefarose/metabolismo , Análise de Sequência de RNA , Água/químicaRESUMO
STUDY DESIGN: Descriptive anatomical study on ovine and human cadaveric lumbar spinal segments. OBJECTIVE: To describe the alternative transpedicular approach to deliver therapeutic agents into intervertebral disc (IVD). SUMMARY OF BACKGROUND DATA: The present delivery approach of therapeutic agents (growth factors/cells/hydrogels) within the IVD is through injection, via the annulus fibrosus (AF). However, it has recently been demonstrated that small needle puncture of the AF leads to further degeneration and disc herniation. In addition, the injected material has a high chance to be extruded through the AF injury. METHODS: Lumbar ovine and human spinal segments were used. Under fluoroscopy, a 2-mm Kirschner wire was introduced in the caudal vertebra through the pedicle and the inferior endplate to the nucleus pulposus. Gross anatomy analysis and high-resolution peripheral quantitative computed tomography (HR-pQCT) were performed to assess the right position of the wire in pedicles. Discography and nucleotomy were performed using a 14G cannula insertion or a 2-mm arthroscopic shaver blade, respectively. Nucleoplasty was also performed with agarose gel/contrast agent and imaged with HR-pQCT. RESULTS: Gross anatomy, fluoroscopy, and HR-pQCT images showed that the nucleus pulposus could be approached through the endplate via the pedicle without affecting the spinal canal and the neural foramina. The contrast agent was delivered into the IVD and nucleus pulposus was removed from the disc and filled with agarose gel. CONCLUSION: This study describes how a transpedicular approach can be used as an alternative route to deliver therapeutic agents to the disc without disruption of the AF showing the potential use of this technique in preclinical research and highlighting its clinical relevance for IVD regeneration.
Assuntos
Sistemas de Liberação de Medicamentos/métodos , Disco Intervertebral/anatomia & histologia , Disco Intervertebral/fisiologia , Regeneração/fisiologia , Animais , Cadáver , Meios de Contraste/administração & dosagem , Fluoroscopia , Géis/administração & dosagem , Humanos , Disco Intervertebral/cirurgia , Vértebras Lombares/diagnóstico por imagem , Vértebras Lombares/fisiologia , Vértebras Lombares/cirurgia , Regeneração/efeitos dos fármacos , Reprodutibilidade dos Testes , Sefarose/administração & dosagem , Ovinos , Tomografia Computadorizada por Raios X/métodosRESUMO
Caenorhabditis elegans larvae display specific behavior and development that is not observed in adults. For example, larvae go through a molting cycle that includes a sleep-like state prior to the molt. The study of these processes requires high-resolution long-term observation of individual animals. Here we describe a method for simultaneous culture and observation of several individual young C. elegans larvae inside agarose hydrogel-based arrayed microcompartments. We used agarose hydrogel microcompartments to observe and quantify larval specific sleep-wake-like behavior and to observe neuronal rewiring using confocal fluorescence microscopy without acute immobilization. We found no behavioral aberrations caused by area restriction. We show that worms cultured inside hydrogel microcompartments develop into normal adults. Thus, hydrogel microcompartments appear useful for long-term observation of larval behavior and development.
Assuntos
Hidrogel de Polietilenoglicol-Dimetacrilato , Sistema Nervoso/crescimento & desenvolvimento , Organogênese/fisiologia , Sefarose , Sono/fisiologia , Vigília/fisiologia , Animais , Caenorhabditis elegans , Técnicas de Cultura/métodos , Hidrogel de Polietilenoglicol-Dimetacrilato/administração & dosagem , Larva/crescimento & desenvolvimento , Sefarose/administração & dosagemRESUMO
The comet assay is now the method of choice for measuring most kinds of DNA damage in cells. However, due to the lack of a standardised protocol inter-laboratory comparisons are of limited value. The aim of this paper is to demonstrate how small changes in comet-assay variables may significantly affect the results. We examined the effect of varying agarose concentrations, alkaline unwinding time, electrophoresis time, voltage and current, by use of two cell types, viz. human peripheral blood lymphocytes and the lymphoblastoid cell line TK-6. All these variables have marked effects on assay performance and, therefore, on the determination of DNA damage. Here we identify factors of particular importance.
Assuntos
Ensaio Cometa/métodos , Ensaio Cometa/normas , Linhagem Celular , Dano ao DNA , Condutividade Elétrica , Eletroforese em Gel de Ágar/métodos , Humanos , Linfócitos/efeitos dos fármacos , Mutagênicos/toxicidade , Sefarose/administração & dosagemRESUMO
BACKGROUND: A constantly increasing number of gel fillers for aesthetic and reconstructive purposes have been introduced during the last 20 years. Most of the new ones are modified versions of the original collagen and hyaluronic acid gels. They have been reconstructed, often by adding cross-bindings to the polymer in order to obtain a more dense molecular structure, which will prolong degradation and filling effect of the gel. Other gel fillers contain particles of organic (poly-lactic acid) or inorganic (calcium hydroxylapatite) material, which have been used in human tissue for other purposes (degradable suture material and bone cement, respectively). The permanent fillers (silicone oil and polyacrylamide gel) have been used for many years, silicone mainly in the US and polyacrylamide gel in most countries outside the US and Canada. OBJECTIVE: Complications occur, and they appear to be more frequent with particulated fillers, polyacrylamide gel and silicone oil. However, these complications differ in nature and depend on the filler type used. METHODS AND MATERIALS: This overview presents the different gel filler types, how they interact with host tissue, and what can go wrong. The results and conclusion are based on experimental and clinical observations coupled with a search of the literature. RESULTS AND CONCLUSION: Complications following homogenous hydrogels are caused by infection with bacteria, which have been inserted into the gel during injection. If not treated with relevant antibiotics (but instead steroids or large doses of NSAIDs) the bacteria form a biofilm, which gives rise to a low-grade chronic infection that is resistant to antibiotics. Complications following particulated gels and silicone oil are not known, but bacteria in a biofilm and/or endotoxins released by these is a possibility which deserves further investigations, primarily by using the fluorescence in situ hybridization (FISH) technique.
Assuntos
Materiais Biocompatíveis/administração & dosagem , Técnicas Cosméticas , Fármacos Dermatológicos/administração & dosagem , Géis/administração & dosagem , Granuloma de Corpo Estranho/induzido quimicamente , Rejuvenescimento , Envelhecimento da Pele/efeitos dos fármacos , Resinas Acrílicas/administração & dosagem , Materiais Biocompatíveis/efeitos adversos , Materiais Biocompatíveis/química , Materiais Biocompatíveis/classificação , Colágeno/administração & dosagem , Fármacos Dermatológicos/efeitos adversos , Fármacos Dermatológicos/química , Fármacos Dermatológicos/classificação , Medicina Baseada em Evidências , Face , Géis/efeitos adversos , Géis/química , Géis/classificação , Granuloma de Corpo Estranho/prevenção & controle , Humanos , Ácido Hialurônico/administração & dosagem , Hidrogéis/administração & dosagem , Injeções/efeitos adversos , Injeções/métodos , Polímeros/administração & dosagem , Sefarose/administração & dosagem , Géis de Silicone/administração & dosagem , Fatores de Tempo , Resultado do TratamentoRESUMO
BACKGROUND: The search for safe and effective tissue fillers has been an ongoing effort in plastic and cosmetic surgery over recent decades. Biocompatibility is a prerequisite for any substance to be used as an implant material, and potential biomaterials need to be characterized by histologic evaluation of tissue responses. Collagen is a well-known tissue filler. Agarose gel is widely used in bioengineering. Both products are considered biocompatible. The purpose of this study was to evaluate the bioactivity of agarose gel as a dermal filler compared with collagen. METHODS: Tissue responses to agarose gel and collagen were evaluated in a rat in vivo model (n = 96). Four groups were evaluated: group 1 (n = 24), rats with agarose gel implants; group 2 (n = 24), rats with collagen implants; group 3, a placebo group (n = 24); and group 4, a control group (n = 24). Responses and biocompatibility were assessed by histopathologic and histomorphometric evaluation at 1 week to 8 months after implantation. RESULTS: Agarose gel showed marked bioactivity and biodegradation, although the implants integrated well into tissues: newly formed collagen bands were observed inside the implants and no granulomas were detected. Collagen implants showed low cell infiltration and a significant loss of product over time. CONCLUSIONS: Agarose gel is a biocompatible product that can be considered for use as a tissue filler. Further investigation is required to assess its long-term efficacy and safety.
Assuntos
Materiais Biocompatíveis/administração & dosagem , Próteses e Implantes , Sefarose/análogos & derivados , Animais , Colágeno/administração & dosagem , Géis , Masculino , Teste de Materiais , Ratos , Ratos Sprague-Dawley , Sefarose/administração & dosagemRESUMO
Three porphyran preparations with high emulsifying ability and varying molecular mass, 3,6-anhydrogalactose content, and sulfate content without any protenaceous component were prepared from dried nori processed from Porphyra yezoensis, a red alga. Each of these preparations was applied to demonstrate adsorption or binding to the surface of oil droplets. The decrease in porphyran concentration of the aqueous phase of O/W emulsions prepared with porphyran and with toluidine blue (TB)-porphyran complex formed by adding TB to the O/W emulsions indicated ready adsorption to the surface of oil droplets. The decrease in zeta-potential of the O/W emulsions suggested that the sulfate groups of the adsorbed porphyran were oriented toward the external aqueous phase. A biomolecular interaction analysis exhibited rapid binding of porphyran to C16-alkane, probably through 3,6-anhydrogalactose. Porphyran-coated liposomes were tolerant to digestion with phospholipase D. The increased molecular weight of the porphyran preparations had an increased effect on these characteristics. The results of this study demonstrate that the emulsifying ability of porphyran is derived from the adequate adsorption to the surface of oil droplets and that porphyran could be effectively applied to stabilize liposomes.
Assuntos
Lipossomos/química , Sefarose/análogos & derivados , Adsorção , Fenômenos Químicos , Físico-Química , Estabilidade de Medicamentos , Emulsões/química , Interações Hidrofóbicas e Hidrofílicas , Fosfolipase D/farmacologia , Porphyra/química , Sefarose/administração & dosagem , Sefarose/análise , Sefarose/químicaRESUMO
Porphyran is a major component of the red algae, Porphyra tenera and P. yezoensis, which are processed into a sheet type of dried food, "Nori". Porphyran has been reported to activate murine macrophages by in vitro and i.p. injection studies. The contact hypersensitivity (CHS) reaction in mice is commonly used as a model to evaluate the anti-allergic activity of food and food components. We therefore studied the effect of porphyran on the CHS reaction in Balb/c mice to evaluate anti-allergic activity of porphyran. We found that an oral administration of porphyran (2% in drinking water) suppressed the CHS reaction (ear edema) induced by 2,4,6-trinitrochlorobenzene. We also found that porphyran suppressed the serum level of IgE and the production of interferon-gamma (IFN-gamma) in the challenged ear lobe. We conclude from these results that the CHS reaction was suppressed by oral porphyran due to the decreased serum level of IgE and the production of IFN-gamma in the challenged ear lobe.
Assuntos
Dermatite de Contato/tratamento farmacológico , Porphyra/química , Sefarose/análogos & derivados , Animais , Antialérgicos/administração & dosagem , Antialérgicos/farmacologia , Antialérgicos/uso terapêutico , Orelha , Edema/induzido quimicamente , Edema/tratamento farmacológico , Imunoglobulina E/sangue , Terapia de Imunossupressão/métodos , Interferon gama/biossíntese , Camundongos , Camundongos Endogâmicos BALB C , Cloreto de Picrila , Sefarose/administração & dosagem , Sefarose/farmacologia , Sefarose/uso terapêuticoRESUMO
OBJECTIVE: To explore the action of pingxiao capsules (PXC) and its significance in the treatment of late stage mammary cancer (LSMC). METHODS: One hundred and forty-two LSMC patients were randomized into four groups: the two single treated groups treated by endocrinotherapy (ET) alone (n = 27) and by chemotherapy alone (n=44) respectively, and the two PXC combined treated groups treated with PXC plus endocrinotherapy (n=27) or chemotherapy (n=44). The remission rate and progression time (TTP) of disease, the survival time and quality of life (QOL) of patients, and the adverse reaction were compared between the single treated groups and the combined treated groups. RESULTS: The median progression time was obviously prolonged, and QOL improved in the combined treated groups than those in the single treated groups (P < 0.05), but no significant difference was found in the remission rate or adverse reaction between them. CONCLUSION: PXC can improve QOL, prolong the progression time in patients of LSMC, and with less adverse reaction. It is worth spreading combination of PXC with chemo- or endocrino-therapy in clinical application for treatment of LSMC patients.
Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Neoplasias da Mama/tratamento farmacológico , Medicamentos de Ervas Chinesas/uso terapêutico , Fitoterapia , Tamoxifeno/uso terapêutico , Adulto , Idoso , Antineoplásicos Hormonais/uso terapêutico , Neoplasias da Mama/patologia , Quimioterapia Combinada , Feminino , Humanos , Pessoa de Meia-Idade , Paclitaxel/administração & dosagem , Sefarose/administração & dosagem , Sefarose/análogos & derivadosRESUMO
OBJECT: The goal of this study was to validate a simple, inexpensive, and robust model system to be used as an in vitro surrogate for in vivo brain tissues in preclinical and exploratory studies of infusion-based intraparenchymal drug and cell delivery. METHODS: Agarose gels of varying concentrations and porcine brain were tested to determine the infusion characteristics of several different catheters at flow rates of 0.5 and 1 microl per minute by using bromophenol blue (BPB) dye (molecular weight [MW] approximately 690) and gadodiamide (MW approximately 573). Magnetic resonance (MR) imaging and videomicroscopy were used to measure the distribution of these infusates, with a simultaneous measurement of infusion pressures. In addition, the forces of catheter penetration and movement through gel and brain were measured. Agarose gel at a 0.6% concentration closely resembles in vivo brain with respect to several critical physical characteristics. The ratio of distribution volume to infusion volume of agarose was 10 compared with 7.1 for brain. The infusion pressure of the gel demonstrated profiles similar in configuration and magnitude to those of the brain (plateau pressures 10-20 mm Hg). Gadodiamide infusion in agarose closely resembled that in the brain, as documented using T1-weighted MR imaging. Gadodiamide distribution in agarose gel was virtually identical to that of BPB dye, as documented by MR imaging and videomicroscopy. The force profile for insertion of a silastic catheter into agarose gel was similar in magnitude and configuration to the force profile for insertion into the brain. Careful insertion of the cannula using a stereotactic guide is critical to minimize irregularity and backflow of infusate distribution. CONCLUSIONS: Agarose gel (0.6%) is a useful surrogate for in vivo brain in exploratory studies of convection-enhanced delivery.
Assuntos
Córtex Cerebral/metabolismo , Sistemas de Liberação de Medicamentos/instrumentação , Imageamento por Ressonância Magnética/instrumentação , Imagens de Fantasmas , Sefarose/farmacocinética , Animais , Azul de Bromofenol/administração & dosagem , Azul de Bromofenol/farmacocinética , Doenças do Sistema Nervoso Central/tratamento farmacológico , Corantes/administração & dosagem , Corantes/farmacocinética , Vias de Administração de Medicamentos , Sistemas de Liberação de Medicamentos/métodos , Géis/administração & dosagem , Géis/farmacocinética , Infusões Intralesionais , Pressão , Sefarose/administração & dosagem , SuínosRESUMO
UNLABELLED: Enzyme ablation of the hyperplastic prostate may be an ideal method of management of BPH. However, the unsatisfactory ablation affects in vivo contrast with successful in vitro results limiting the enthusiasm for further research. In this study, we make efforts to solve the problems in the use of enzyme ablation of BPH in vivo and to measure satisfactory effect. MATERIAL AND METHODS: A total of 18 hybrid dogs between the ages of 7 and 11 y underwent this experiment. Eight dogs were divided into four groups according to the injection formula: enzyme solution, hot D-Hanks' plus enzyme solution, hot agarose plus enzyme solution, and hot agarose solution alone. After selecting the agarose plus enzyme solution group in the first month, the remainder 10 dogs were treated with this two-stage method. Intravenous or oral antibiotics were administered perioperatively. All operations were performed directly by way of laparotomy. The prostates were observed and harvested with surrounding tissue at 24 hrs, 7 days, 14 days, 1 month and 3-5 months after treatment. Gross and microscopic examinations were performed. RESULTS: Only agarose plus enzyme group shows obvious cavity formation with concomitant size reduction and softening of the prostate ablation effect in the four groups. At 24 h after injection, the prostates demonstrated cavity formation containing liquefied necrotic tissue. The liquefied tissue was absorbed in 7-14 days. At 1 month, the size of most prostates decreased with a corresponding decrease in the size of the cavities. The cavities nearly disappeared within 3-5 months, and the size of prostates decreased to between 1/2 and 1/4 of the pretreatment sizes. All prostates had intact urethral mucosa and capsule. No complications directly related to enzyme ablation were identified. In the control groups there were no significant cavities or decrease in prostate size. CONCLUSIONS: This two-stage thermal and enzyme ablative method can significantly ablate prostate tissue without identifiable complications, and would be possibly applied to treating human BPH in the future.
Assuntos
Colagenases/administração & dosagem , Próstata/patologia , Hiperplasia Prostática/terapia , Sefarose/administração & dosagem , Administração Oral , Animais , Antibacterianos/administração & dosagem , Terapia Combinada , Cães , Temperatura Alta , Injeções Intravenosas , Laparotomia , Masculino , Projetos Piloto , Próstata/enzimologia , Hiperplasia Prostática/enzimologia , Tripsina/administração & dosagemRESUMO
BACKGROUND: Animal models are indispensable in order to investigate the mechanism of various diseases and to explore the counter measures for those disease states. Although there are several animal models of ischemic heart diseases, surgical interventions required to create myocardial ischemia sometimes give rise to a problem in the yield of model. This study describes a new technique for inducing myocardial ischemia in rats. METHODS AND RESULTS: A 0.014-inch guidewire was introduced via the carotid artery and selectively advanced into the coronary arteries under fluoroscopy. Transmural myocardial ischemia was confirmed by ST-segment elevation and by the appearance of left ventricular wall motion abnormalities on the echocardiogram. Reversibility of the wire-induced myocardial ischemia was demonstrated by complete resolution of both ST-segment elevation and wall motion abnormalities after removing the wire. CONCLUSION: Wire-induced myocardial ischemia was reproducible and is less invasive than conventional ischemic models in rats. This method is a powerful and useful tool for the investigation of ischemic heart disease in small animals.
Assuntos
Modelos Animais , Isquemia Miocárdica/etiologia , Animais , Cateterismo Cardíaco/instrumentação , Doença das Coronárias/etiologia , Eletrocardiografia , Embolia/etiologia , Masculino , Microesferas , Isquemia Miocárdica/diagnóstico por imagem , Isquemia Miocárdica/fisiopatologia , Ratos , Ratos Wistar , Reprodutibilidade dos Testes , Sefarose/administração & dosagem , Sefarose/toxicidade , UltrassonografiaRESUMO
Understanding neural cell differentiation and neurite extension in three-dimensional scaffolds is critical for neural tissue engineering. This study explores the structure-function relationship between a 3D hydrogel scaffold and neural cell process extension and examines the role of ambient charge on neurite extension in 3D scaffolds. A range of agarose hydrogel concentrations was used to generate varied gel physical structures and the corresponding neurite extension was examined. Agarose gel concentration and the corresponding pore radius are important physical properties that influence neural cell function. The average pore radii of the gels were determined while the gel was in the hydrated state and in two different dehydrated states. As the gel concentration was increased, the average pore radius decreased exponentially. Similarly, the length of neurites extended by E9 chick DRGs cultured in agarose gels depends on gel concentration. The polycationic polysaccharide chitosan and the polyanionic polysaccharide alginate were used to incorporate charge into the 3D hydrogel scaffold, and neural cell response to charge was studied. Chitosan and alginate were covalently bound to the agarose hydrogel backbone using the bi-functional coupling agent 1,1'-carbonyldiimidazole. DRGs cultured in chitosan-coupled agarose gel exhibited a significant increase in neurite length compared to the unmodified agarose control. Conversely, the alginate-coupled agarose gels significantly inhibited neurite extension. This study demonstrates a strong, correlation between the ability of sensory ganglia to extend neurites in 3D gels and the hydrogel pore radius. In addition, our results demonstrate that charged biopolymers influence neurite extension in a polarity dependent manner.
Assuntos
Regeneração Nervosa , Neurônios/fisiologia , Alginatos/farmacologia , Animais , Embrião de Galinha , Quitina/análogos & derivados , Quitina/farmacologia , Quitosana , Técnicas de Cultura , Relação Dose-Resposta a Droga , Gânglios Espinais/efeitos dos fármacos , Gânglios Espinais/crescimento & desenvolvimento , Gânglios Espinais/fisiologia , Hidrogéis/administração & dosagem , Neuritos/fisiologia , Neurônios/efeitos dos fármacos , Sefarose/administração & dosagemRESUMO
In an animal model of hind limb ischemia we documented the levels of endogenous basic fibroblast growth factor (bFGF) in control and ischaemic hind limbs, and evaluated the response to the administration of exogenous recombinant bFGF and heparin. Variations in this model were tested for their ability to alter the development of the collateral circulation. Recovery after acute arterial occlusion was significantly delayed by immediate bilateral mirror-image arterial ligations, when compared with either unilateral arterial ligation or delayed contralateral ligations performed after 2 months. If the major veins were also occluded all limbs developed gangrene, tissue loss and a marked delay in the recovery of blood flow, while none of the animals with unilateral arterial ligations developed gangrene. This indicates that the recovery in blood flow during the acute phase in this model is dependent on collateral vessels from the contralateral iliac artery and that major venous occlusion impedes the development of collateral vessels. Lumbar sympathectomy did not alter the recovery of blood flow after arterial occlusion, suggesting that collateral blood flow is not significantly influenced by autonomic neural supply. Following arterial occlusion there was a ten-fold increase in the levels of endogenous bFGF in all ischaemic muscle groups. Intramuscular implantation of bFGF in heparin-sepharose pellets at the time of arterial ligation markedly enhanced the blood flow for 3 weeks compared with untreated ischaemic limbs. A further increment in blood flow occurred if an additional dose of bFGF was administered 4 weeks after ligation.(ABSTRACT TRUNCATED AT 250 WORDS)
Assuntos
Circulação Colateral/efeitos dos fármacos , Fator 2 de Crescimento de Fibroblastos/administração & dosagem , Heparina/administração & dosagem , Membro Posterior/irrigação sanguínea , Isquemia/tratamento farmacológico , Animais , Arteriopatias Oclusivas/tratamento farmacológico , Arteriopatias Oclusivas/fisiopatologia , Modelos Animais de Doenças , Fator 2 de Crescimento de Fibroblastos/fisiologia , Isquemia/fisiopatologia , Masculino , Ratos , Ratos Wistar , Sefarose/administração & dosagemRESUMO
Two novel immunization methods designed for immunization with small quantities of antigen, immobilized on a solid matrix and without the use of adjuvant, are presented. The major test antigen used in order to evaluate these methods was bovine serum albumin (BSA). It was deposited in the spleen of mice and rabbits, either attached to Sepharose beads (Pharmacia Sepharose 4B) or to nitrocellulose (NC) paper strips (Millipore). BSA was attached to NC by direct application or by electroblotting after SDS-polyacrylamide gel electrophoresis. The antibody response in mouse and rabbit serum, after intrasplenic immunizations with various quantities of antigen, was analyzed in an ELISA standard procedure. In mice, an antibody response in serum was detected after three intrasplenic immunizations with a total quantity of 73.6 ng BSA bound to Sepharose beads and after two immunizations with a total quantity of 800 ng BSA attached to NC. Determination of the antigen-binding to NC and the clearance rate of antigen attached to NC deposited in the spleen of mice was performed with 125I-labeled BSA. In rabbits, an antibody response in serum was detected after a single intrasplenic immunization with 2.6 micrograms BSA attached to NC. When testing human insulin and sheep prolactin, attached to NC, as antigens in intrasplenic immunization of rabbits, an antibody response was found after a total quantity of 3.2 micrograms insulin and 10.5 micrograms prolactin, respectively.
Assuntos
Antígenos/administração & dosagem , Colódio/imunologia , Imunização/métodos , Sefarose/imunologia , Animais , Formação de Anticorpos/efeitos dos fármacos , Antígenos/imunologia , Colódio/administração & dosagem , Vias de Administração de Medicamentos , Injeções , Injeções Intraperitoneais , Masculino , Camundongos , Camundongos Endogâmicos CBA , Camundongos Endogâmicos , Ligação Proteica , Coelhos , Sefarose/administração & dosagem , Soroalbumina Bovina/administração & dosagem , Soroalbumina Bovina/imunologia , BaçoRESUMO
Poly(rI).poly(rC) induces a lytic reaction in interferon-treated mouse LM cells. We have attempted to determine whether the intracellular penetration of poly(rI).poly(rC) is a prerequisite for cell lysis and to gain some insight into the pathway followed. We found that poly(rI).poly(rC) coupled to Sepharose beads was unable to generate lysis of interferon-treated cells whereas the cells underwent lysis after microinjection of poly(rI).poly(rC). Some inhibitors of endocytosis were found to inhibit the development of the lytic reaction. Lysosomotropic amines or a low temperature (19 degrees C) blocked endocytosis of poly(rI).poly(rC) but did not prevent its uptake. The internalization of poly(rI).poly(rC) was energy-dependent and was blocked when sodium azide and 2-deoxyglucose were added simultaneously. We conclude that poly(rI).poly(rC) is internalized and reaches an acidic compartment before triggering the lytic reaction in the cell.
Assuntos
Endocitose , Interferons/farmacologia , Poli I-C/metabolismo , Aminas/farmacologia , Animais , Células Cultivadas , Endocitose/efeitos dos fármacos , Cinética , Camundongos , Microinjeções , Poli I-C/farmacologia , Polilisina/administração & dosagem , Quinacrina/farmacologia , Sefarose/administração & dosagem , TemperaturaRESUMO
Eleven dogs with spontaneous neoplasms were intensively treated with an immunoadsorption system consisting of a continuous flow centrifuge, Protein A-Sepharose columns, and a semi-automatic elution system. Despite consistent and substantial lowering of immunoglobulin G levels, tumor regression was noted in only one of 11 dogs. In contrast, infusion of small volumes of plasma after incubation with heat and formalin-treated Staphylococcus aureus Cowan I resulted in a tumoricidal response in five of six animals. These results suggest that tumor necrosis is probably not induced by Protein A-mediated removal of humoral "blocking" factors.