Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “In vitro model”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 613 records · Page 34Linked to original sources
PubMed2000

Investigating plant-based medicines for wound healing with the use of cell culture technologies and in vitro models: a review.

INTRODUCTION: Cell culture and molecular technologies are basic yet sophisticated research tool used to investigate plant-based medicine for wound healing. METHODS: Cell viability and proliferation assay is used to determine whether there are any positive effects and to discover what is the limiting cytotoxic concentration in vitro. The scratch technique, fibroblast-populated collagen lattices and aortic rings embedded gels are used as the in-vitro models of wound re-epithelialization, contraction and angiogenesis. The immunofluorescence, immunoblotting and organotypic culture can be used to detect expression of specific proteins that are modulated by plant extracts during the wound healing process. MAIN FINDINGS: Given the dynamics of the wound healing process, cell culture and molecular technologies are advantageous in providing us with detailed studies and analysis of each intricate process. CONCLUSION: The scientific approaches for the study of traditional plant-based remedies for wound healing will provide us an important platform for rigorous testing and evaluation of their clinical efficacy based on accepted rules of evidence.

Cell Survival↗
PubMed1984

Paraquat-induced injury of type II alveolar cells. An in vitro model of oxidant injury.

Paraquat, a widely used herbicide, causes severe, often fatal lung damage. In vivo studies suggest the alveolar epithelial cells (types I and II) are specific targets of paraquat toxicity. This study used 51Cr-labeled type II cells to demonstrate that paraquat (10-5 M) resulted in type II cell injury in vitro, independent of interacting immune effector agents. With 51Cr release expressed as the cytotoxic index (Cl), type II cell injury was found to accelerate with increasing paraquat concentrations (10(-5) M, 10(-4) M, and 10(-3) M, resulting in a Cl of 12.5 +/- 2.2, 22.8 +/- 1.8, and 35.1 +/- 1.9, respectively). Paraquat-induced cytotoxicity (10(-4) M, with a Cl of 22.8 +/- 1.8) was effectively reduced by catalase 1,100 U/ml (Cl 8.0 +/- 3.2, p less than 0.001), superoxide dismutase, 300 U/ml (Cl 17.4 +/- 1.7, p less than 0.05), alpha tocopherol, 10 micrograms/ml (Cl 17.8 +/- 1.6, p less than 0.05). Paraquat toxicity (10(-3) M) was potentiated in the presence of 95% O2 with an increase in Cl from 31.1 +/- 1.7 to 36.4 +/- 2.3 (p less than 0.05). Paraquat-induced type II cell injury was noted as early as 4 h incubation by electron microscopic evidence of swelling of mitochondrial cristae and dispersion of nuclear chromatin. Thus, this in vitro model indicates that paraquat-induced type II cell injury can be quantified, confirmed by morphologic ultrastructural changes, significantly reduced by antioxidants, and potentiated by hyperoxia.

Animals↗
PubMed2006

An in vitro model of early islet amyloid polypeptide (IAPP) fibrillogenesis using human IAPP-transgenic mouse islets.

The mechanisms underlying insufficient insulin secretion and loss of beta-cell mass in feline and human type 2 diabetes mellitus are incompletely understood. However, islet amyloid polypeptide (IAPP)-derived islet amyloidosis (IA) has been linked to increased rates of beta-cell apoptosis and, therefore, our goal was to develop an in vitro model of IAPP fibrillogenesis using isolated pancreatic islets from mice transgenic for human IAPP (hIAPP Tg mice). Islets from hIAPP Tg mice, from mice transgenic for non-amyloidogenic murine IAPP (mIAPP Tg mice), and from the FVB background strain were exposed to normal (5.5 mM) or high (28 mM) glucose conditions in cell culture for 8 days. On days 0 and 8, islets were collected for electron microscopy (EM). EM showed no abnormalities in the mIAPP Tg or FVB islets at either time point. On day 8, hIAPP Tg islets cultured at high glucose concentration formed extracellular IAPP-derived flocculent deposits. No significant differences in rates of apoptosis were found between groups. Our findings, therefore, show that in vitro culture of hIAPP Tg mouse islets under high glucose conditions produces a readily available and rapidly inducible model of IAPP-derived fibrillogenesis and enables the study of early phases of the molecular pathogenesis of IA.

Amyloid↗
PubMed1994

The in vitro model of tissue cyst formation in Toxoplasma gondii.

Fundamental advances in the development and design of drugs for toxoplasmosis will only follow a more-thorough understanding o f the basic biology of Toxoplasma gondii tissue cyst formation. Tim McHugh, Richard Holliman and Philip Butcher here describe the in vitro model of tissue cyst formation in T. gondii.

Journal Article↗
PubMed2003

In vivo and in vitro models demonstrate a role for caveolin-1 in the pathogenesis of ischaemic acute renal failure.

Caveolae and their proteins, the caveolins, transport macromolecules; compartmentalize signalling molecules; and are involved in various repair processes. There is little information regarding their role in the pathogenesis of significant renal syndromes such as acute renal failure (ARF). In this study, an in vivo rat model of 30 min bilateral renal ischaemia followed by reperfusion times from 4 h to 1 week was used to map the temporal and spatial association between caveolin-1 and tubular epithelial damage (desquamation, apoptosis, necrosis). An in vitro model of ischaemic ARF was also studied, where cultured renal tubular epithelial cells or arterial endothelial cells were subjected to injury initiators modelled on ischaemia-reperfusion (hypoxia, serum deprivation, free radical damage or hypoxia-hyperoxia). Expression of caveolin proteins was investigated using immunohistochemistry, immunoelectron microscopy, and immunoblots of whole cell, membrane or cytosol protein extracts. In vivo, healthy kidney had abundant caveolin-1 in vascular endothelial cells and also some expression in membrane surfaces of distal tubular epithelium. In the kidneys of ARF animals, punctate cytoplasmic localization of caveolin-1 was identified, with high intensity expression in injured proximal tubules that were losing basement membrane adhesion or were apoptotic, 24 h to 4 days after ischaemia-reperfusion. Western immunoblots indicated a marked increase in caveolin-1 expression in the cortex where some proximal tubular injury was located. In vitro, the main treatment-induced change in both cell types was translocation of caveolin-1 from the original plasma membrane site into membrane-associated sites in the cytoplasm. Overall, expression levels did not alter for whole cell extracts and the protein remained membrane-bound, as indicated by cell fractionation analyses. Caveolin-1 was also found to localize intensely within apoptotic cells. The results are indicative of a role for caveolin-1 in ARF-induced renal injury. Whether it functions for cell repair or death remains to be elucidated.

Acute Kidney Injury↗
PubMed1999

Biocompatibility of a silicone-coated polypropylene hollow fiber oxygenator in an in vitro model.

BACKGROUND: A silicone-coated microporous hollow-fiber membrane oxygenator has been developed to prevent plasma leakage during long-term use. The objective of this study was to evaluate the biocompatibility of the oxygenator. METHODS: A silicone-coated oxygenator was compared with an uncoated oxygenator in an in vitro model of cardiopulmonary bypass. Simulated circulation was maintained for 6 h at 37 degrees C. RESULTS: Platelet counts decreased significantly (p < 0.05) and leukocyte counts tended to decline; however, the differences between groups were not significant. Concentrations of C3a increased significantly in both groups (p < 0.05), but levels were significantly less in the silicone-coated oxygenator (p = 0.008). In contrast, concentrations of C4a, beta-thromboglobulin, and granulocyte elastase increased significantly (p < 0.05), but the differences between groups were not significant. CONCLUSIONS: Silicone coating over a microporous hollow-fiber membrane may improve biocompatibility by reducing C3a activation.

Coated Materials, Biocompatible↗
PubMed1996

Elastase-induced matrix degradation in arterial organ cultures: an in vitro model of aneurysmal disease.

PURPOSE: Abdominal aortic aneurysms are characterized by degradation of the extracellular matrix, induction of endogenous metalloproteinases (MMPs), and development of a chronic inflammatory infiltrate. Despite intensive analysis of end-stage tissue, aneurysm pathogenesis remains obscure. The aim of this study was to develop an in vitro model of aneurysmal disease. METHODS: Porcine aortic organ cultures were preincubated with pancreatic elastase before culture in standard conditions for up to 14 days. The extent of matrix degradation at various time points was determined by quantitative histologic estimation of collagen and elastin concentration. Endogenous metalloproteinase production within the tissue was quantified by gel enzymography and immunoblotting. A separate series of experiments was performed to investigate the effect of incorporating autologous leukocytes into the culture system. RESULTS: Although exogenous elastase was removed after 24 hours, substantial degradation of the aortic extracellular matrix occurred in the subsequent 13 days in tissue culture. Analysis of samples preincubated with elastase (100 U/ml) for 24 hours before tissue culture demonstrated that elastin degradation occurred in a time-dependent manner (p < 0.001) and was not confined to the initial phase of exogenous elastase activity. Gelatin gel enzymography revealed a time-related production of metalloproteinases (55 to 250 kDa) within the aortic tissue. The presence of MMPs-1, 2, 3, and 9 was determined by immunoblotting. Immunohistochemistry identified the vascular smooth-muscle cell as the source of MMPs-1, 2, and 3. Addition of autogenous leukocytes to elastase-pretreated tissue initiated an inflammatory infiltrate within the aortic wall, which further enhanced both matrix degradation and MMP production (p < 0.001). CONCLUSIONS: These data demonstrate that aortic samples pretreated with elastase before tissue culture undergo matrix degradation with MMP production and the development of an inflammatory infiltrate. These changes mirror the pathophysiological events within established aneurysms. It is suggested that this model may be useful in understanding early pathogenic events within aneurysmal tissue.

Animals↗
PubMed1984

Experimental evaluation of arterial steal in in vitro models of femoro-tibial bypass with adjuvant arteriovenous shunt.

Arteriovenous shunts are now increasingly used with long femoro-tibial grafts in critical ischaemia of the lower limb. This might result in reduction in blood flow to an already compromised tibial artery, a condition known as arterial 'steal'. In vitro models of the femoro-tibial bypass with adjuvant arteriovenous shunt were investigated in terms of flow rate distribution. Results show that arterial steal will occur at high flow rates through the shunt only when a significant proximal stenosis is present. The degree of steal was independent of the configuration and size of the shunts studied. A simple resistance model was used to predict steal under various flow conditions. The clinical significance of the results is discussed.

Arteriovenous Shunt, Surgical↗
PubMed2000

Episialin acts as an antiadhesive factor in an in vitro model of human endometrial-blastocyst attachment.

Episialin, which is found on the apical membrane of human endometrial epithelium, has been postulated to act as an antiadhesive factor through the steric hindrance generated by its extensively glycosylated structure. The present studies were designed to test this hypothesis in an in vitro model of endometrial-blastocyst attachment. Episialin was expressed in human endometrial carcinoma cells (HEC-1A > RL95-2), and attachment of JAr choriocarcinoma cells to the endometrial cell monolayers was inversely related to episialin expression. Treatment of endometrial monolayers with type III sialidase increased JAr binding, and this increase was suppressed by HMFG1, a monoclonal antibody specific for episialin. The effects of sialidase appear to have resulted from a contaminant protease rather than from a loss of sialic acid residues, because sialidase preparations other than type III were ineffective. After sialidase treatment, conditioned medium from cells treated with type III sialidase contained more episialin than medium from cells treated with other sialidase preparations. Similar attachment-assay results were obtained using O-sialoglycoprotein endopeptidase; after treatment, the increase in JAr binding (>50%) was suppressed by the antiepisialin antibody. These results demonstrate for the first time that episialin acts as an antiadhesive agent in a model of human endometrial-blastocyst attachment.

Blastocyst↗
PubMed2003

Linezolid compared with eperezolid, vancomycin, and gentamicin in an in vitro model of antimicrobial lock therapy for Staphylococcus epidermidis central venous catheter-related biofilm infections.

Central venous catheter (CVC)-related infection (CVC-RI) is a common complication of CVC use. The most common etiological agents of CVC-RI are gram-positive organisms, in particular, staphylococci. An in vitro model for the formation of biofilms by Staphylococcus epidermidis ATCC 35984 on polyurethane coupons in a modified Robbins device was established. Biofilm formation was confirmed by electron microscopy and was quantified by determination of viable counts. Mueller-Hinton broth was replaced with sterile physiological saline (control) or a solution of vancomycin (10 mg/ml), gentamicin (10 mg/ml), linezolid (2 mg/ml), or eperezolid (4 mg/ml). Viable counts were performed with the coupons after exposure to antimicrobials for periods of 24, 72, 168, and 240 h. The mean viable count per coupon following establishment of the biofilm was 4.6 x 10(8) CFU/coupon, and that after 14 days of exposure to physiological saline was 2.5 x 10(7) CFU/coupon. On exposure to vancomycin (10 mg/ml), the mean counts were 2.5 x 10(7) CFU/coupon at 24 h, 4.3 x 10(6) CFU/coupon at 72 h, 1.4 x 10(5) CFU/coupon at 168 h, and undetectable at 240 h. With gentamicin (10 mg/ml) the mean counts were 2.7 x 10(7) CFU/coupon at 24 h, 3.7 x 10(6) CFU/coupon at 72 h, 8.4 x 10(6) CFU/coupon at 168 h, and 6.5 x 10(6) CFU/coupon at 240 h. With linezolid at 2 mg/ml the mean counts were 7.1 x 10(5) CFU/coupon at 24 h and not detectable at 72, 168, and 240 h. With eperezolid (4 mg/ml) no viable cells were recovered after 168 h. These data suggest that linezolid (2 mg/ml) and eperezolid (4 mg/ml) achieve eradication of S. epidermidis biofilms more rapidly than vancomycin (10 mg/ml) and gentamicin (10 mg/ml).

Acetamides↗
PubMed2004

Smoke induced changes in epithelial cell gene expression: development of an in vitro model for COPD.

Chronic obstructive pulmonary disease (COPD) includes emphysema and chronic bronchitis, which are characterised by a progressive airflow limitation and chronic inflammation. The pathogenesis of COPD involves different cells, mainly epithelial cells, macrophages, neutrophils, and CD8 lymphocytes. Bronchial epithelium lines the mucosal surface of the airways, forming a mechanical barrier that separates the external environment from the internal milieu. Recently, substantial evidence has emerged indicating that airway epithelial cells are able to liberate a number of chemokines fundamental to both inflammatory and immune responses. Therefore, we established an in vitro model by showing that cigarette smoke is able to induce the release of chemokines by lung epithelial cells. Furthermore, we show that cigarette smoke induced chemokine expression is resistant to dexamethasone, mimicking the clinical situation. In contrast, pyrrolidinedithiocarbamic acid, an experimental antioxidant compound, inhibited smoke induced chemokine expression. These results suggest that this epithelial cell culture model may allow the evaluation of novel anti-inflammatory compounds for the treatment of COPD directly on the relevant target cells in vitro. This approach may result in the replacement of animal experimentation in screening of new therapeutics for COPD.

Adenocarcinoma↗
PubMed2002

The effect of changing pressures on dural puncture and leak with various spinal needles on an in vitro model.

Postdural puncture headache is one of the most serious complications of spinal anesthesia. In this study, spinal needles of various types and shapes were used to investigate the amount of fluid leakage in dural puncture under various levels of pressures. Dura samples received from 10 cadavers were fixed in an in vitro model. The dural punctures were inflicted with 22 G, 25 G, and 27 G Quincke; 25 G Withacre; 25 G, 27 G Pencan, and 26 G Atraucan spinal needles. The fluid, which leaked during the process, was collected under the pressures of 0, 25, 50, 100, and 150 cm H(2)O in one-hour period for each level. The holes in the dura were studied under light microscope. While 22 G and 25 G Quincke needles were used, the fluid leakage directly correlated the amount of liquid, the diameter of the needle, and the pressure used. The puncture of 25 G Withacre and 25 G Pencan presented a leakage which did not significantly vary with the liquid pressure and was of lesser amount. In 26 G Atraucan, 27 G Pencan, and 27 G Quincke inflicted punctures, little liquid was collected and it did not vary with differing pressures. Thus, no significant correlation was established between the needle diameter and the puncture. It was concluded that the sharp-ended needles could not endure changes in the pressure. However, those needles with a very thin diameter and a pencil tip were considered as safe tools for anesthetical practices.

Aged↗
PubMed1991

Differential effects of interferon gamma and alpha on in vitro model of angiogenesis.

The formation of blood vessels in vivo (angiogenesis) is an important process and is usually initiated in response to injury, tumor growth, or normal tissue development. We have studied the effect of human interferon (IFN) alpha (alpha) and gamma (gamma) on the capillary-like network formation in an in vitro model of angiogenesis using human umbilical vein endothelial cells (HUVEC). When HUVEC cells are plated on Matrigel (reconstituted basement membrane matrix enriched in laminin), a network of capillary like structures (endotubes) rapidly forms. IFN-alpha enhanced the tube formation in a dose-dependent manner, whereas IFN-gamma significantly inhibited the tube formation. In addition, both the enhancement and inhibition of angiogenesis by IFN-alpha and gamma was found to be greater if the cells were pretreated with IFN for 12 hr before plating on the Matrigel. These results suggest that IFN may play an important role in several vascular processes including early stages of wound healing, recanalization of thrombi, tumor growth, metastasis, normal growth, and development.

Endothelium, Vascular↗
PubMed2005

Electrophysiological effects of azimilide in an in vitro model of simulated-ischemia and reperfusion in guinea-pig ventricular myocardium.

There are few investigations on azimilide effects during ischemia/reperfusion. We have therefore investigated low concentrations of azimilide (0.1 and 0.5 micromol/l) versus Controls on action potential parameters and occurrence of repetitive responses during simulated ischemia and reperfusion. An in vitro model of "border zone" in guinea-pig ventricular myocardium (n=30) was used. Azimilide 0.5 micromol/l lengthened action potential duration in normoxic but not in ischemic-like conditions. Therefore an increased dispersion of action potential duration at 90% of repolarization during simulated ischemia in presence of azimilide was seen. Upon reperfusion, both normal and reperfused myocardium showed azimilide-induced action potential duration increase. There was a neutral effect on the occurrence of arrhythmias during simulated ischemia; however azimilide showed significant (P=0.033) antiarrhythmic properties following reperfusion. To mimic I(Kr) and I(Ks) blocking properties of azimilide we further used dofetilide 10 nmol/l with HMR 1556 1 nmol/l (N=9), which was accompanied by less severe shortening (P<0.05) of action potential duration at 90% of repolarization at 30 min of ischemic-like conditions (-43+/-9%), as compared with azimilide 0.5 micromol/l (-64+/-5%) but similar to what seen with azimilide 0.1 micromol/l (-53+/-5%) and Controls (-52+/-6%). During reperfusion, 2/9 (22%) preparations had sustained activities, which was less than what observed in Controls (5/10, 50%) and with azimilide 0.5 micromol/l (0/10, 0%), although not statistically different (respectively, P=0.35 and P=0.21). Lack versus homogenous class III effects of azimilide in respectively simulated ischemia and reperfusion may explain its different efficacy on arrhythmias, although prevention of reperfusion arrhythmias calls for other than just its I(Kr) and I(Ks) blocking properties.

Action Potentials↗
PubMed1991

The focally demyelinated rat fimbria: a new in vitro model for the study of acute demyelination in the central nervous system.

We have produced controlled local demyelination in Wistar rat fimbriae by injection of microliter quantities of the detergent lysophosphatidyl choline (LPC) stereotactically. Six to seven days later the hippocampus and fornix was dissected out en bloc and maintained in vitro for electrical evaluation of conduction through the damaged area. The tissue was then fixed for verification of the lesion by light and electron microscopy. All fimbriae showed a normal conducted action potential with a latency of 0.5 to 1.5 ms when the conduction distance was 4-5 mm. LPC-lesioned fimbriae also showed a later wave with a latency of 4-5 ms. This later wave had the same stimulus-response curve as the primary action potential, but was more sensitive to repeated stimulation. We interpret this wave as evidence of conduction into or through a demyelinated region. LPC-lesioned fimbriae also showed histological evidence of demyelination. This preparation provides an in vitro model for the study of acute local demyelination of central nervous system white matter, such as that induced by multiple sclerosis and other focally demyelinating diseases.

Acute Disease↗
PubMed1987

An in vitro model for analyzing the nephrotoxicity of cyclosporine and preservation injury.

Renal damage caused by cyclosporine (CsA) has been documented. Clinical experiences have shown preservation injury further potentiates CsA nephrotoxicity. This study examined the mechanism of nephrotoxicity defined by changes in protein synthesis, DNA synthesis, and ornithine decarboxylase activity in an in vitro model. Initial results showed that CsA inhibited dog kidney epithelium cell (MDCK) replication at a dose of 200 ng after 24 hr (P less than .01) and 100 ng after 48 hr (P less than .01). Protein synthesis was inhibited with 100 ng after 24 and 48 hr (P less than .01). There was a reduction in ODC activity with 200 ng CsA (P less than .05). Methods for simulating transplant-related injuries were then developed. Under ischemic conditions, 18 hr were required before a synergistic effect with CsA produced a reduction in replication (P less than .05). Incubation of MDCK cells in preservative solution at 4 degrees C under hypoxic conditions resulted in a time-dependent reduction in synthetic and replicative capacity that plateaued at 24 hr (P less than .01). The next step was to simulate the clinical situation by combining treatments. MDCK cells were incubated for 24 hr in preservative solution under hypoxic conditions at 4 degrees C, and then CsA was added at defined intervals. The addition of CsA before 24 hr resulted in a significant decrease in cell replication (P less than .05) compared with CsA addition after 48 hr. Similar results were obtained with cells incubated for 48 hr in preservative solution with hypoxia. These data suggest that renal injury from ischemia and cold storage requires a period of cellular repair and replication. Administration of CsA before this period results in further renal injury. Our analysis offers an explanation of CsA nephrotoxicity seen in the human situation and, therefore, may provide a model for studying human nephrotoxicity.

Cell Survival↗
PubMed1988

Antibacterial activity in human urine of fosfomycin trometamol in an in vitro model of the urinary bladder.

The urinary concentrations of fosfomycin trometamol, norfloxacin, pipemidic acid and cotrimoxazole were studied at various times after oral administration of drugs in healthy volunteers. Using the same urine, the bactericidal activity of four antimicrobial agents against Escherichia coli, Proteus mirabilis and Klebsiella pneumoniae in an in vitro model simulating the treatment of bacterial cystitis was also evaluated. The results obtained show that very high concentrations of the drugs were achieved in urine particularly after the oral administration of the fosfomycin trometamol. In the bladder model bactericidal activity of fosfomycin trometamol, norfloxacin and pipemidic acid were higher than that of cotrimoxazole; no resistant mutants to drugs were selected over a period of 24 h.

Administration, Oral↗
PubMed2005

Redox proteomics identification of oxidatively modified proteins in Alzheimer's disease brain and in vivo and in vitro models of AD centered around Abeta(1-42).

Alzheimer's disease is a progressive neurodegenerative disease associated with loss of memory and cognition. One hallmark of AD is the accumulation of amyloid beta-peptide (Abeta), which invokes a cascade of oxidative damage to neurons that can eventually result in neuronal death. Several markers of oxidative stress have been identified in AD brain, thus providing greater understanding into potential mechanisms involved in the disease pathogenesis and progression. In the present article, we review the application of redox proteomics to the identification of oxidized proteins in AD brain and also our recent findings on amyloid beta-peptide (Abeta)-associated in vivo and in vitro models of AD. Our redox proteomics approach has made possible the identification of specifically oxidized proteins in Alzheimer's disease (AD) brain, providing for the first time evidence on how oxidative stress plays a crucial role in AD-related neurodegeneration. The information obtained has great potential to aid in determining the molecular pathogenesis in and detecting disease markers of AD, as well as identifying potential targets for drug therapy in AD. Application of redox proteomics to study cellular events, especially related to disease dysfunction, may provide an efficient tool to understand the main mechanisms involved in the pathogenesis and progression of oxidative stress-related neurodegenerative disorders.

Alzheimer Disease↗