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1.
Transplant Proc ; 50(2): 493-498, 2018 Mar.
Article in English | MEDLINE | ID: mdl-29579834

ABSTRACT

BACKGROUND: Around 2.4% of the world's population is infected with hepatitis C virus (HCV), and it is the most common cause of liver transplantation (LT) in the world. Latin America (LA), with nearly 9% of the world population, has had a continuous increase in the number of LTs per year. Yet, due to the lack of mandatory data collection and a well-developed health-care system, access to transplantation is limited in most LA countries. We report the first LA experience of HCV-infected LT patients. METHODS: We performed a retrospective cohort study by reviewing the medical histories of all HCV-infected LT patients between 1996 and 2016 who acquired HCV before their LT, at the Fundación Valle del Lilí, Cali, Colombia. RESULTS: Between January 1996 and December 2015, a total of 770 LTs were performed, of which 75 had a cirrhotic liver due to HCV infection. With a median follow-up time of 24.4 months (interquartile range [IQR] 4.7-61.2 months), patient survival was 44.9% and 66.9% for the time periods 1996-2006 and 2007-2015, respectively. Hepatocellular carcinoma (HCC) was present in 30.6% of the patients, and overall postoperative complications had an incidence of 80%. CONCLUSIONS: This is the first report of LT in HCV-infected patients in Colombia and in LA. Our results are comparable to those of other transplant centers worldwide with regard to postoperative complications and patient survival. Patients with LT in the 1996-2006 time frame had higher morbidity and mortality. Studies including larger numbers of patients are needed to determine the reason for this finding.


Subject(s)
Hepatitis C/surgery , Liver Transplantation , Adult , Carcinoma, Hepatocellular/complications , Carcinoma, Hepatocellular/epidemiology , Cohort Studies , Colombia , Female , Hepacivirus , Hepatitis C/complications , Humans , Incidence , Liver Neoplasms/complications , Liver Neoplasms/epidemiology , Liver Transplantation/mortality , Male , Middle Aged , Postoperative Complications , Retrospective Studies
2.
J Hosp Infect ; 100(3): e196-e199, 2018 Nov.
Article in English | MEDLINE | ID: mdl-29588187

ABSTRACT

Healthcare-associated infections, particularly central-line-associated bloodstream infections (CLABSIs), are worrisome in neonates. This study describes the impact of chlorhexidine baths on CLABSI rates in a neonatal intensive care unit in a developing country, through a quasi-experimental study undertaken over 62 months (January 2012 to February 2017) divided into two periods: before and after the implementation of a protocol for chlorhexidine baths in July 2014. The rate of CLABSIs per 1000 central-line-days decreased from 8.64 to 4.28 after implementation of the protocol. The use of chlorhexidine baths appears to reduce the number of CLABSIs in neonates.


Subject(s)
Bacteremia/prevention & control , Baths/methods , Catheter-Related Infections/prevention & control , Catheterization, Central Venous/adverse effects , Chlorhexidine/administration & dosage , Cross Infection/prevention & control , Disinfectants/administration & dosage , Bacteremia/epidemiology , Catheter-Related Infections/epidemiology , Cross Infection/epidemiology , Developing Countries , Humans , Infant, Newborn , Intensive Care Units, Neonatal , Non-Randomized Controlled Trials as Topic , Prevalence
3.
J Biol Regul Homeost Agents ; 30(4 Suppl 1): 33-40, 2016.
Article in English | MEDLINE | ID: mdl-28002898

ABSTRACT

The possible toxic effects of intra-articular tranexamic acid (TA) are still debated. The aim of this study was to evaluate TA effects on human cartilage fragments and synovial biopsies. Explant culture of minced articular cartilage underwent prolonged TA exposure. Histological analysis, immunofluorescence and colorimetric assay for quantification of s-GAG and DNA were performed at the end term. Synoviocytes were cultured for 48h in presence of TA. Light microscopy and flow cytometry analysis were performed at the end of the exposure to TA and one week after the treatment. TA exposure did not influence i) the chondrocyte outgrowth and migration, ii) the expression of chondrogenic and proliferative markers and iii) the s-GAG/DNA ratio. TA treatment did not affect synoviocytes' morphology and treated cells were phenotypically similar to control cells. This study demonstrated that TA does not negatively affect chondrocytes and synoviocytes cultured in vitro. Thus, our findings may be clinically relevant in order to validate the intra-articular TA administration during orthopedic procedures.


Subject(s)
Cartilage, Articular/drug effects , Tranexamic Acid/pharmacology , Cartilage, Articular/cytology , Cells, Cultured , Chondrocytes/cytology , Chondrocytes/drug effects , Chondrogenesis/drug effects , Humans , Synoviocytes/cytology , Synoviocytes/drug effects , Tranexamic Acid/adverse effects
4.
Br J Pharmacol ; 171(10): 2621-30, 2014 May.
Article in English | MEDLINE | ID: mdl-24308803

ABSTRACT

BACKGROUND AND PURPOSE: Osteoporosis is a condition characterized by a decrease in bone density, which decreases its strength and results in fragile bones. The endocannabinoid/endovanilloid system has been shown to be involved in the regulation of skeletal remodelling. The aim of this study was to investigate the possible modulation of bone mass mediated by the transient receptor potential vanilloid type 1 channel (TRPV1) in vivo and in vitro. EXPERIMENTAL APPROACH: A multidisciplinary approach, including biomolecular, biochemical and morphological analysis, was used to investigate the involvement of TRPV1 in changes in bone density in vivo and osteoclast activity in vitro, in wild-type and Trpv1(-/-) mice, that had undergone ovariectomy or had a sham operation. KEY RESULTS: Genetic deletion of Trpv1 as well as pharmacological inhibition/desensitization of TRPV1 signalling dramatically reduced the osteoclast activity in vitro and prevented the ovariectomy-induced bone loss in vivo, whereas the expression of cannabinoid type 2 (CB2 ) receptors was increased. CONCLUSIONS AND IMPLICATIONS: These findings highlight the pivotal role TRPV1 channels play in bone resorption and suggest a possible cross-talk between TRPV1 and CB2 receptors. Based on these results, hybrid compounds acting on both TRPV1 and CB2 receptors in an opposite manner could provide a future pharmacological tool for the treatment of diseases associated with disturbances in the bone remodelling process.


Subject(s)
Bone Density Conservation Agents/pharmacology , Bone Remodeling/drug effects , Capsaicin/analogs & derivatives , Osteoclasts/drug effects , Osteoporosis, Postmenopausal/prevention & control , Ovariectomy , Signal Transduction/drug effects , TRPV Cation Channels/antagonists & inhibitors , TRPV Cation Channels/deficiency , Animals , Bone Density/drug effects , Capsaicin/pharmacology , Cells, Cultured , Disease Models, Animal , Dose-Response Relationship, Drug , Female , Humans , Mice, Inbred C57BL , Mice, Knockout , Osteoclasts/metabolism , Osteoporosis, Postmenopausal/genetics , Osteoporosis, Postmenopausal/metabolism , Receptor Cross-Talk , Receptor, Cannabinoid, CB2/drug effects , Receptor, Cannabinoid, CB2/metabolism , TRPV Cation Channels/genetics
5.
Biomed Res Int ; 2013: 539348, 2013.
Article in English | MEDLINE | ID: mdl-23710450

ABSTRACT

We study the interaction of 3T3 Swiss albino mouse fibroblasts with polymeric nanoparticles (NPs) and investigate cellular behaviour in terms of viability/cytotoxicity, cell cycle, NPs uptake, MAP kinase (ERK1/2), and focal adhesion kinase (FAK) activation. After incubation of NPs with cell culture media, western blot analysis showed that Vitronectin is retained by NPs, while Fibronectin is not detected. From cytotoxicity studies (MTT and BrdU methods) an LD50 of about 1.5 mg/mL results for NPs. However, NPs in the range 0.01-0.30 mg/mL are able to trigger a statistically significant increase in proliferation and cell cycle progression in dose and time depending manner. Also, biochemical evaluation of ERK1/2 and FAK clearly shows an increasing phosphorylation in a dose and time depending manner. Finally, we found by transmission electron microscopy that NPs are internalised by cells. Competitively blocking VN-integrin receptors with echistatin (1 µg/mL) results in a decrease of viability/proliferation, cell cycle progression, cellular uptake, and FAK/ERK activation showing the involvement of Vitronectin receptors in signal transduction. In conclusion, our results show that cell surface NPs interactions are mediated by absorbed plasma proteins (i.e., Vitronectin) that represent an external stimuli, switched to the nucleus by FAK enzyme, which in turn modulate fibroblasts viability/proliferation.


Subject(s)
Cell Proliferation/drug effects , Cell Survival/drug effects , Nanoparticles/administration & dosage , Vitronectin/administration & dosage , Animals , Cell Adhesion/drug effects , Fibroblasts/cytology , Fibroblasts/drug effects , Fibronectins/metabolism , Focal Adhesion Protein-Tyrosine Kinases/metabolism , Humans , In Vitro Techniques , MAP Kinase Signaling System/drug effects , Mice , Nanoparticles/chemistry , Phosphorylation , Signal Transduction , Swiss 3T3 Cells , Vitronectin/chemistry
6.
J Mater Sci Mater Med ; 24(6): 1473-81, 2013 Jun.
Article in English | MEDLINE | ID: mdl-23471500

ABSTRACT

This paper focused on the biodistribution of the cross-linked hyaluronic acid (HA-NPs) sub-micron particles in tumor-bearing mice. Solvent-non solvent method followed glutaraldehyde cross-linking utilized for the fabrication of HA-NPs. Size measurement and morphological analysis were performed by dynamic light scattering and electron microscopy, respectively and the size found to be in the range of 200-400 nm. In vitro viability in LNCaP cell line was assessed by water soluble tetrazolium assay after 24 h of exposure to sub-micron particles and no toxicity was found to higher concentration of 3 mg/mL. Internalization of particles in prostate cancer cell LNCaP were studied by confocal microscopy with FITC labeled submicron particles and involvement of hyaluronan receptor mediated uptake/endocytosis was confirmed by competitive assay. Biodistribution studies were performed in xenograft prostate cancer mice model with fluorophore labeled particles and monitored in tumoral parenchyma with strong fluorescence, meanwhile very less signal in liver, kidney and spleen while no fluorescence found in lung after 24 h of systemic administration; that shown ability of this HA based system to recognize cancer tissue. These result fetched that hyaluronic acid based system is selective for tumoral site and can be utilized to deliver bioactives in specific (targeting) and controlled (temporal) manner to cancerous tissue.


Subject(s)
Hyaluronic Acid/chemistry , Nanocapsules/chemistry , Prostatic Neoplasms/chemistry , Animals , Cross-Linking Reagents/chemistry , Diffusion , Kinetics , Male , Materials Testing , Mice , Nanocapsules/ultrastructure , Organ Specificity , Particle Size , Tissue Distribution
7.
J Cell Physiol ; 228(5): 968-74, 2013 May.
Article in English | MEDLINE | ID: mdl-23042505

ABSTRACT

Thyroid cancer is not very common, accounting for 1-2% of all cancers, with a population incidence of about 0.004%. Currently, the ability to discriminate between follicular adenoma and carcinoma represents the major challenge in preclinical diagnosis of thyroid proliferative lesions. Better discrimination between the two would help avoid unnecessary thyroidectomy and save valuable resources. Over the years, galectin-3 (Gal-3) has been proposed as a diagnostic marker with varied success. In this paper, we used Environmental Scanning Electron Microscopy Immunogold Labelling (ESEM-IGL) to investigate the expression of Gal-3 on Thin-Prep fine needle aspiration cytology (FNAC). We optimized the ESEM-IGL method on thyroid cell lines (RO-82 and FTC-133) comparing our membrane Gal-3 labeling data with Western blot. We evaluated 183 thyroid FNAC from Italian patients with a uncertain pre-surgical diagnosis. ESEM-IGL method marker sensitivity is 71.2%, while specificity is 53.3% and diagnostic efficacy is 61.2%. Our results confirmed that Gal-3 expression is associated with situations of hypertrophy and/or cellular hyperproliferation, pathophysiological situations common both to adenomas and to thyroid carcinomas. The innovation of thyroid FNAC Thin-Prep ESEM-IGL shows the levels of Gal-3 immunolabeling clearly, even through the individual cells of a thyroid nodule. However, Gal-3 alone, as a molecular marker of thyroid cancer, can still have a limited application in pre-surgery diagnosis.


Subject(s)
Adenoma/diagnosis , Carcinoma/diagnosis , Galectin 3/metabolism , Thyroid Neoplasms/diagnosis , Biopsy, Fine-Needle , Cytodiagnosis , Diagnosis, Differential , Gene Expression Regulation, Neoplastic , Humans , Microscopy, Electron, Scanning , Thyroid Gland/cytology , Thyroid Gland/pathology , Thyroid Neoplasms/pathology
9.
J Orthop Traumatol ; 12(3): 131-6, 2011 Sep.
Article in English | MEDLINE | ID: mdl-21698373

ABSTRACT

BACKGROUND: Total knee arthroplasty (TKA) is the appropriate treatment for degenerative pathology of the knee. Implant surveillance is mandatory to improve clinical results. We present the long-term results of a series of consecutive TKA Press Fit Condylar (J&J), cemented fixed bearing with selective patellar resurfacing in nonselected patients. MATERIALS AND METHODS: In this prospective case series, 223 TKA were clinically and radiographically evaluated using the Hospital for Special Surgery (HSS) knee score and the Knee Society Roentgenographic Evaluation and Scoring System. RESULTS: There were 197 patients, with an average age of 68.4 years [95% confidence interval (CI) 52.7-84.1 years]; 49 arthroplasties were implanted in men (21.1%) and 184 (78.9%) in women. The average follow-up was approximately 13.5 years (162.1 months; 95% CI 132.3-191.9), and it was possible to evaluate 179 implants (76.8% of the implanted prosthesis) in 176 patients. The average HSS score increased from 61.5 (95% CI 60.4-62.7) to 89.4 (95% CI 87.7-.93.5) points. The cumulative average survival rate at 15 years (the endpoint being failure with revision) was 90.6%  ± 2% standard deviation. Resurfacing the patella did not make a difference in terms of implant survival. Progressive radiolucent lines were observed around 20 implants (14.3%); all were revised. CONCLUSIONS: The PFC system is an excellent prosthetic solution. Early clinical complications, mechanical axis and patellar resurfacing do not correlate with implant failure, whereas progressive radiolucent lines do.


Subject(s)
Arthritis, Rheumatoid/surgery , Arthroplasty, Replacement, Knee/methods , Bone Cements/therapeutic use , Equipment Failure Analysis , Osteoarthritis, Knee/surgery , Postoperative Complications/diagnostic imaging , Aged , Aged, 80 and over , Female , Follow-Up Studies , Humans , Kaplan-Meier Estimate , Male , Middle Aged , Osteotomy/methods , Patella/surgery , Prospective Studies , Radiography , Time Factors
10.
J Microsc ; 241(1): 83-93, 2011 Jan.
Article in English | MEDLINE | ID: mdl-21118204

ABSTRACT

We have combined environmental scanning electron microscopy (ESEM) and immunogold labelling (IGL) for the analysis of cell morphology and surface protein detection on human fine needle aspiration, which is processed in thin uniform monolayer (a single layer of cells) on a glass slide by Thin Prep technology. Among scanning electron microscopy techniques, we choose the environmental modality (ESEM) because it allows a slight manipulation of biological samples and an operational time comparable with cytological techniques. Moreover, the Thin Prep technology confirmed a reproducible cell monolayer on glass smear, minimizing problems for the determination of appropriate amount of material per slide. The first experimental data in ESEM-IGL on biological samples with fine needle aspiration Thin Prep, in human thyroid nodules, showed that cells retained their morphology and provided a clear IGL. The optimization of conditions (i.e. vacuum pressure, temperature and relative humidity) confirmed the possibility to observe an immunolabelled biological sample and morphological signal, joined with compositional informations, due to peculiar characteristics of gaseous secondary electron detector in ESEM. The ESEM-IGL and fine needle aspiration Thin Prep could be used in combination for the interpretation of cell morphology and cell surface immunolabelling. Our paper suggests this use as a powerful diagnostic tool in a pre-surgical evaluations, opening a new applicative window for electron microscopy.


Subject(s)
Cytological Techniques/methods , Immunohistochemistry/methods , Microscopy, Electron, Scanning/methods , Thyroid Gland/cytology , Biopsy, Fine-Needle , Humans
11.
G Chir ; 31(6-7): 312-5, 2010.
Article in Italian | MEDLINE | ID: mdl-20646380

ABSTRACT

BACKGROUND: The postoperative hypoparathyroidism is a not rare complication after total thyroidectomy and/or total parathyroidectomy. Attempts to transplant parathyroid tissue began in 1975 with the work of Wells, but still today results are disappointing. However, with the development of tissue engineering techniques, some experimental approaches to build artificial parathyroid are been made. Bioengineered device, actively secreting PTH, for transplant in patients with iatrogenic hypoparathyroidism is unavailable. PATIENTS AND METHODS: Parathyroid cells were obtained from three chronic uremic patients in hemodialysis, operated for secondary hyperparathyroidism. Cell cultures in RPMI medium were subsequently seeded on collagen scaffold (three-dimensional matrix with slow biodegradation). Collagen is the major component of the extracellular matrix and thus is a good substrate for cell adhesion and growth. Culture media, with a low calcium concentration, were optimised to physiologically stimulate parathyroid hormone secretion. Cell cultures were morphologically observed in optical and electron (ESEM) microscopy and metabolically assayed by MTT method until the tenth week. Besides, concentration of parathyroid hormone in the culture medium has been measured for several weeks. RESULTS: After 24 hours of culture in RPMI, cells extracted from human parathyroid glands were nearly all adherent and organised in clusters to resemble the glandular organization. The cellular population consisted predominantly of parathyroid cells (90-95%). On collagen scaffolds, cells maintains an epithelial-like morphology also after 10 weeks, colonizing the scaffold surface and keeping a good proliferative rate with a discrete production of parathyroid hormone. CONCLUSION: The use of parathyroid cells extracted from patients with secondary hyperparathyroidism was certainly an appropriate choice that enabled us to achieve these results, that albeit partial bode well for the experimental in vivo animal model. The bioengineered scaffolds when implanted in the subcutaneous can avoid the dispersion of parathyroid cells, assuring also the possibility to easily remove the implant in case of complications. Our research was aimed primarily to the optimisation of PTH secreting human parathyroid cells cultures and then to the in vitro engineering of human parathyroid glands in three-dimensional collagen scaffolds.


Subject(s)
Collagen , Parathyroid Glands/cytology , Tissue Engineering/methods , Cell Adhesion , Cells, Cultured , Extracellular Matrix , Humans , Parathyroid Glands/metabolism , Parathyroid Hormone/metabolism
12.
Transpl Infect Dis ; 11(2): 112-21, 2009 Apr.
Article in English | MEDLINE | ID: mdl-19254327

ABSTRACT

Although invasive candidiasis (IC) causes significant morbidity and mortality in patients who undergo heart, lung, or heart-lung transplantation, a systematic study in a large cohort of thoracic organ transplant recipients has not been reported to date. Clinical and microbiological data were reviewed for 1305 patients who underwent thoracic organ transplantation at Stanford University Medical Center between 1980 and 2004. We identified and analyzed 76 episodes of IC in 68 patients (overall incidence 5.2% per patient).The incidence of IC was higher in lung (LTx) and heart-lung transplant (HLTx) recipients as compared with heart transplant (HTx) recipients (risk ratio [RR] 1.7, 95% confidence interval [CI] 1.1-2.7).The incidence of IC decreased over time in all thoracic organ transplant recipients, decreasing from 6.1% in the 1980-1986 time period to 2.1% in the 2001-2004 era in the HTx recipients, and from 20% in the 1980-1986 period to 1.8% in the 2001-2004 period in the LTx and HLTx recipients.The most common site of infection differed between the HTx and LTx cohorts, with bloodstream or disseminated disease in the former and tracheobronchitis in the latter. IC in the first year after transplant was significantly associated with death in both HTx (RR 2.9, 95% CI 1.8-4.6, P=0.001) and LTx and HLTx patients (RR 3.0, 95% CI 1.9-4.6, P<0.001). The attributable mortality from IC decreased during the 25-year period of observation, from 36% to 20% in the HTx recipients and from 39% to 15% in the LTx and HLTx recipients. There were a significant number of cases caused by non-albicans Candida species in all patients, with a trend toward higher mortality in the HTx group. In conclusion, the incidence and attributable mortality of IC in thoracic organ transplant recipients has significantly declined over the past 25 years.The use of newer antifungal agents for prophylaxis and treatment, the decrease in the incidence of cytomegalovirus disease, and the use of more selective immunosuppression, among other factors, may have been responsible for this change.


Subject(s)
Candidiasis/epidemiology , Heart Transplantation/adverse effects , Heart-Lung Transplantation/adverse effects , Lung Transplantation/adverse effects , Postoperative Complications/epidemiology , Adolescent , Adult , Aged , Antifungal Agents/therapeutic use , California/epidemiology , Candida/classification , Candida/isolation & purification , Candidiasis/etiology , Candidiasis/mortality , Candidiasis/prevention & control , Child , Child, Preschool , Databases, Factual , Female , Humans , Immunosuppressive Agents/adverse effects , Immunosuppressive Agents/therapeutic use , Incidence , Infant , Infant, Newborn , Male , Middle Aged , Postoperative Complications/microbiology , Postoperative Complications/mortality , Postoperative Complications/prevention & control , Young Adult
13.
Paediatr Anaesth ; 15(6): 491-4, 2005 Jun.
Article in English | MEDLINE | ID: mdl-15910350

ABSTRACT

BACKGROUND: Previous published data comparing ropivacaine 0.2% with levobupivacaine 0.25% have suggested that ropivacaine might be associated with less early postoperative motor blockade compared with levobupivacaine. The aim of the present study was to further investigate this issue comparing equal concentrations (0.2%) of ropivacaine and levobupivacaine in children undergoing minor subumbilical surgery. METHODS: Following induction of a standardized anesthetic, patients (1-7 years) were randomized in a double-blind manner to receive a caudal block with either ropivacaine 0.2% (group R, n=30) or levobupivacaine 0.2% (group L, n=30), total volume 1 ml.kg-1. Motor blockade (modified Bromage scale; primary end-point) and analgesia [Children and Infants Postoperative Pain Scale (CHIPPS) score] were assessed at predetermined time points during the first 24-postoperative hours. RESULTS: Motor blockade was only registered during the first postoperative hour with no significant differences between the groups (group R n=5, group L n=8). Postoperative CHIPPS scores were almost identical in both groups with only seven and six patients requiring supplemental analgesia (CHIPPS score>or=4) in the R and L groups, respectively. CONCLUSIONS: A 0.2% concentrations of ropivacaine or levobupivacaine are clinically very similar with regard to postoperative analgesia and unwanted postoperative motor blockade in children undergoing minor subumbilical surgery.


Subject(s)
Amides , Anesthesia, Caudal , Anesthetics, Local , Bupivacaine/analogs & derivatives , Child , Child, Preschool , Double-Blind Method , Humans , Infant , Levobupivacaine , Neuromuscular Blockade , Pain, Postoperative/drug therapy , Pain, Postoperative/epidemiology , Preanesthetic Medication , Prospective Studies , Ropivacaine
14.
Prensa méd. argent ; 92(7): 418-424, 2005. tab
Article in Spanish | BINACIS | ID: bin-874

ABSTRACT

Los tumores carcinoides son neoplasias poco frecuentes en el tubo digetivo y que se desarrollan a partir de las células que forman el sistema APUD o neuroendocrinas. El objetivo es analizar la nueva nomenclatura, la incidencia en el aparato digetivo, la presentación clínica, diagnóstico y tratamiento quirúrgico


Subject(s)
Male , Humans , Female , APUD Cells , Neuroendocrine Tumors/chemistry , Neuroendocrine Tumors/diagnosis , Neuroendocrine Tumors/immunology , Neuroendocrine Tumors/surgery , Intestinal Neoplasms , Intestines , Histological Techniques
15.
Prensa méd. argent ; 92(7): 418-424, 2005. tab
Article in Spanish | LILACS | ID: lil-421313

ABSTRACT

Los tumores carcinoides son neoplasias poco frecuentes en el tubo digetivo y que se desarrollan a partir de las células que forman el sistema APUD o neuroendocrinas. El objetivo es analizar la nueva nomenclatura, la incidencia en el aparato digetivo, la presentación clínica, diagnóstico y tratamiento quirúrgico


Subject(s)
Male , Humans , Female , APUD Cells , Intestinal Neoplasms , Intestines , Neuroendocrine Tumors , Histological Techniques
16.
J Mater Sci Mater Med ; 15(6): 679-86, 2004 Jun.
Article in English | MEDLINE | ID: mdl-15346735

ABSTRACT

Copolymerisation of charged and neutral monomers is a well-known methodology to introduce charged moieties in a polymeric chain to obtain polyelectrolytes. New polyelectrolyte complexes have been synthesised by radical copolymerisation of neutral methacrylic monomer 2-hydroxyethyl methacrylate (HEMA) with cationic 2-methacryloyloxyethyltrimethyl ammonium chloride and anionic 2-acrylamido-2-methylpropane-sulphonic acid monomers in 10:1:1 and 10:1:2 stechiometric ratio. Chemical structure of the synthesised terpolymers was confirmed by FT-IR spectroscopy, moreover, X-ray photoelectron spectroscopy showed the presence of a cationic charge excess on the 10:1:2 terpolymer surface with respect to 10:1:1 terpolymer. Swelling studies for 10:1:2 terpolymers showed a high water content in the swollen state and a "smart behaviour" upon changes in external stimuli such as pH, while, 10:1:1 terpolymer presented the behaviour of a neutral polymer. Mechanical and differential scanning calorimetry analysis confirmed that terpolymer networks were stabilised by ionic co-operative interactions. Infact, the inclusion of oppositely ionic charges in the polymeric network of p(HEMA) represent a way to achieve higher elastic modulus as they stabilise the terpolymer networks. Cytotoxicity and cytocompatibility studies demonstrated that all materials were not toxic, moreover, the presence of a cationic charge excess on 10:1:2 terpolymer surface was able to promote fibroblast adhesion.


Subject(s)
Acrylamides/chemistry , Alkanesulfonates/chemistry , Biocompatible Materials/chemistry , Fibroblasts/cytology , Fibroblasts/physiology , Methacrylates/chemistry , Polyhydroxyethyl Methacrylate/chemistry , Prostheses and Implants , Absorption , Cell Adhesion , Cell Division , Cell Size , Cell Survival , Cells, Cultured , Elasticity , Electrolytes/chemistry , Humans , Hydrogen-Ion Concentration , Surface Properties , Tensile Strength , Water/chemistry
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