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1.
Burns ; 48(2): 263-280, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-34903405

RESUMO

Stevens-Johnson's Syndrome (SJS) and Toxic Epidermal Necrolysis are rare, life-threatening dermatologic conditions with acute onset and not clearly established treatment protocol. A plethora of observational studies are present with lack of up-to-date consensus based on evaluation of objective endpoints, among others mortality. Thorough analysis of available databases (Pubmed, EMBASE, Cinahl, Web of Science, Clinical Trials) was conducted according to PRISMA guidelines. Authors initially identified 700 papers, with 82 of them potentially eligible according to adopted criteria. A total of 42 studies were included into pooled synthesis. For continuous outcomes we analyzed the pooled means for endpoint scores using observed cases data. Categorical outcomes were analyzed by calculating the pooled event rates. We conducted subgroup and exploratory maximum likelihood random effects meta-regression analyses regarding SCORTEN of all outcomes. Using random-effects model, the overall pooled Mortality Rate was 0.191 (95%CI, 0.132-0.269). The lowest mortality rate was found to be linked with Etanercept and highest in Total Plasma Exchange (TPE) and Intravenous Immunoglobulin (IVIG). Overall reepithelization was 13.278 days (95%CI, 8.773-17.784),The highest was found in cyclosporine treatment; 14.739 whilst the lowest for steroids. Length of hospital stay in overall analysis was 19.99 days (95%CI, 16.53-23.44),the highest was linked with TPE/TPE+IvIg treatment, the lowest with steroids. Risk of bias of assessed studies was estimated to be high (for observational studies mean STROBE score 12.44). High quality TEN and SJS studies are lacking. Almost all papers report observational data without randomization and double-blind control. Therefore, the pooled analysis cannot be presented with initial bias. In our meta-analysis the most successful regimen was Etanercept treatment. It was linked with the lowest mortality. The most negative treatment outcome was observed in studies reporting TPE and IVIG. Randomized trials of high quality are needed in SJS and TEN.


Assuntos
Queimaduras , Síndrome de Stevens-Johnson , Queimaduras/tratamento farmacológico , Etanercepte/uso terapêutico , Humanos , Imunoglobulinas Intravenosas/uso terapêutico , Tempo de Internação , Ensaios Clínicos Controlados Aleatórios como Assunto , Estudos Retrospectivos , Esteroides/uso terapêutico
2.
Dis Esophagus ; 34(12)2021 Dec 24.
Artigo em Inglês | MEDLINE | ID: mdl-34155508

RESUMO

Geographic differences in eosinophilic esophagitis (EoE) prevalence suggest the possibility that environmental exposures contribute to EoE pathogenesis. We aimed to examine the association between environmental quality and risk of EoE, using the Environmental Quality Index (EQI), which provides quantification of environmental quality in five domains: air, land, water, built, and sociodemographic for all counties in the United States. To do this, we performed a case-control study in a large pathology database. EoE cases were defined by ≥15 eosinophils per high-power field with other pathologic diagnoses excluded; controls did not have EoE. The pathology data were geocoded and linked with the EQI by county of residence. Logistic regression was used to estimate odds ratio (OR and 95% confidence interval [CI]) of EoE with overall EQI and for each domain, after adjusting for sex, age, and proportion minority race or ethnicity at the county level (higher EQI score indicates worse environmental quality). Of 29,802 EoE cases and 593,329 controls analyzed, odds of EoE were highest in the worst quintile of EQI (OR 1.25; 95% CI: 1.04-1.50), which was largely explained by poor scores in the water domain (OR: 1.33; 1.17-1.50). Conversely, odds of EoE were reduced with higher scores in the air domain (OR: 0.87, 0.74-1.03) and land domain (OR 0.87; 0.76-0.99). Poor EQI, mostly reflected by poor water quality, was associated with increased odds of EoE, while poor air and land quality were inversely associated with EoE. Additional work to identify specific water pollutants that may have an etiologic role in EoE may be warranted.


Assuntos
Esofagite Eosinofílica , Estudos de Casos e Controles , Exposição Ambiental/efeitos adversos , Esofagite Eosinofílica/epidemiologia , Esofagite Eosinofílica/etiologia , Humanos , Razão de Chances , Prevalência , Estados Unidos/epidemiologia
5.
Clin Toxicol (Phila) ; 52(3): 198-206, 2014 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-24580060

RESUMO

CONTEXT: Poison centers (PCs) play an important role in poison prevention and treatment. Studies show that PCs reduce system-wide cost by reducing the number of unnecessary visits to emergency departments and by providing improved patient management. However, there remains a debate regarding the impact of PCs on patient outcomes at the hospital level. OBJECTIVE: To evaluate the impact of PC involvement on length of hospitalization and total hospital charges. MATERIALS AND METHODS: We conducted a retrospective analysis of inpatient cases treated in Illinois hospitals in 2010. We linked the Illinois Poison Center database with an Illinois hospital billing dataset and controlled for important patient-level and facility-level covariates. RESULTS: In the multivariable model, length of hospitalization among PC-assisted patients was 0.58 days shorter than that of patients without PC assistance (p < 0.001). Hospital charges for PC-assisted patients in the lower quintiles were significantly higher than patients without PC assistance (+$953; p < 0.001), but were substantially lower in the most costly quintile of patients (-$4852; p < 0.001). Balancing the higher charges for treating patients with PC assistance in the lower quintiles with the savings in the highest quintile, among inpatients there is a potential cumulative decrease of $2,078 in hospital charges per 10 patients. DISCUSSION: Among the inpatient cases, PC assistance was associated with lower total charges only among the most expensive to treat. However, this outlier group is very important when discussing medical costs. It has been repeatedly shown that the majority of treatment costs are attributable to a small fraction of patients as seen in this study.


Assuntos
Preços Hospitalares , Tempo de Internação , Centros de Controle de Intoxicações , Intoxicação/economia , Adolescente , Adulto , Idoso , Criança , Pré-Escolar , Redução de Custos , Feminino , Humanos , Lactente , Recém-Nascido , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Estados Unidos
6.
Folia Biol (Praha) ; 60(5): 213-9, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25863038

RESUMO

We studied malignant melanoma cell line Me45 and human ovarian carcinoma cell line SKOV-3 (resistant to cisplatin, adriamycin and diphtheria toxin), assessing their expression level of p53, HSP70 and glutathione S-transferase GST-π before and after chemotherapy with cisplatin. These proteins may be responsible for the occurrence of chemoresistance in cancer patients. To assess protein expression we used the immunocytochemical Avidin-Biotin-peroxidase Complex (ABC) method. Before application of chemotherapy, proteins p53, HSP70 and GST-π were present in 100 % of the examined melanoma cells. After the treatment, the intensity of the immunocytochemical reaction for p53 increased, whereas the intensity of immunocytochemical staining for HSP70 and GST-π decreased. In SKOV-3 cells, p53 and HSP70 were present in 100 % of the examined cells both prior to chemotherapy and after it. However, the intensity of the immunocytochemical reaction for p53 decreased, while that of HSP70 increased. As regards GST-π, only 5 % of all examined SKOV-3 cells revealed its expression before chemotherapy. Incubation with cisplatin caused an elevation in the number of ovarian cancer cells expressing GST-π up to 50 %. Moreover, the intensity of the immunocytochemical reaction for GST-π significantly increased.


Assuntos
Antineoplásicos/farmacologia , Cisplatino/farmacologia , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Linhagem Celular Tumoral , Resistencia a Medicamentos Antineoplásicos/genética , Feminino , Glutationa S-Transferase pi/genética , Proteínas de Choque Térmico HSP70/genética , Humanos , Imuno-Histoquímica , Técnicas In Vitro , Melanoma/genética , Melanoma/fisiopatologia , Neoplasias Ovarianas/genética , Neoplasias Ovarianas/fisiopatologia , Proteína Supressora de Tumor p53/genética
7.
Equine Vet J ; 45(2): 204-8, 2013 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-22853551

RESUMO

REASONS FOR PERFORMING STUDY: Dexmedetomidine has been administered in the equine as a constant-rate infusion (CRI) during inhalation anaesthesia, preserving optimal cardiopulmonary function with calm and coordinated recoveries. Inhalant anaesthetic sparing effects have been demonstrated in other species, but not in horses. OBJECTIVES: To determine the effects of a CRI of dexmedetomidine on the minimal alveolar concentration (MAC) of sevoflurane in ponies. METHODS: Six healthy adult ponies were involved in this prospective, randomised, crossover, blinded, experimental study. Each pony was anaesthetised twice (3 weeks washout period). After induction with sevoflurane in oxygen (via nasotracheal tube), the ponies were positioned on a surgical table (T0), and anaesthesia was maintained with sevoflurane (expired sevoflurane fraction 2.5%) in 55% oxygen. The ponies were randomly allocated to treatment D (dexmedetomidine 3.5 µg/kg bwt i.v. [T10-T15] followed by a CRI of dexmedetomidine at 1.75 µg/kg bwt/h) or treatment S (bolus and CRI of saline at the same volume and rate as treatment D). After T60, MAC determination, using a classic bracketing technique, was initiated. Stimuli consisted of constant-current electrical stimuli at the skin of the lateral pastern region. Triplicate MAC estimations were obtained and averaged in each pony. Monitoring included pulse oximetry, electrocardiography, anaesthetic gas monitoring, arterial blood pressure measurement and arterial blood gases. Normocapnia was maintained by mechanical ventilation. Analysis of variance (treatment and period as fixed factors) was used to detect differences between treatments (α= 0.05). RESULTS: An intravenous (i.v.) dexmedetomidine CRI decreased mean ± s.d. sevoflurane MAC from 2.42 ± 0.55 to 1.07 ± 0.21% (mean MAC reduction 53 ± 15%). CONCLUSIONS AND POTENTIAL RELEVANCE: A dexmedetomidine CRI at the reported dose significantly reduces the MAC of sevoflurane.


Assuntos
Analgésicos não Narcóticos/farmacocinética , Anestésicos Inalatórios/farmacocinética , Dexmedetomidina/farmacocinética , Cavalos , Éteres Metílicos/farmacocinética , Analgésicos não Narcóticos/administração & dosagem , Anestésicos Inalatórios/administração & dosagem , Animais , Dexmedetomidina/administração & dosagem , Esquema de Medicação , Interações Medicamentosas , Feminino , Injeções Intravenosas , Masculino , Éteres Metílicos/administração & dosagem , Alvéolos Pulmonares , Sevoflurano
8.
Clin Exp Dermatol ; 34(3): 369-71, 2009 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-19040519

RESUMO

Eosinophilic folliculitis (EF) is a descriptive histopathological term applied to a heterogeneous group of disorders. In EF, the characteristic histopathological features are eosinophilic spongiosis and pustulosis involving the infundibular region of the hair follicle. EF may be seen in association with bacterial and fungal infection, drug reactions and haematological disorders. However, in those conditions, the histopathological changes are rarely restricted to the infundibula but in most cases include a moderate to dense perifollicular or even diffuse dermal infiltrate of lymphocytes, or eosinophilic or neutrophilic granulocytes. We present two cases of EF after mini-allogeneic bone-marrow transplantation (BMT) in order to highlight this rare and perhaps under-recognized clinical association.


Assuntos
Transplante de Medula Óssea/efeitos adversos , Eosinofilia/diagnóstico , Foliculite/diagnóstico , Diagnóstico Diferencial , Eosinofilia/etiologia , Eosinofilia/patologia , Feminino , Foliculite/etiologia , Foliculite/patologia , Doença Enxerto-Hospedeiro/diagnóstico , Folículo Piloso/patologia , Humanos , Masculino , Pessoa de Meia-Idade
9.
J Mater Sci Mater Med ; 17(1): 69-79, 2006 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-16389474

RESUMO

The hydroxyls present on the surface of hydroxyapatite (HA) granules, annealed at 700 composite function, 900 composite function and 1,100 composite function C, are able to initiate the polymerization of epsilon-caprolactone (CL), not only at 185 composite function C under vacuum, but also at room temperature in open system. A polymer layer ionically linked to the substrate is formed on HA surface, enhancing the compatibility between the organic phase and the inorganic one in composite biomaterials. We studied the characteristics of the polymer, produced by the reaction carried out at room temperature in open system, as well as the percentages of the poly(epsilon-caprolactone) (PCL) ionically bonded to the HA structure and of the "free" one. Both percentages appear very dependent on the annealing temperature; in particular, HA annealed for 1 h at 1,100 composite function C is the most efficient initiator of the reaction leading to ionically bonded PCL. The percentages of "free" polymer are much higher than at 185 composite function C under vacuum. Its formation is attributed to the role of water in opening the CL rings, and to the presence of CO(3) (2-) and HPO(4) (2-) ions in the HA annealed at lower temperatures. The presence of water appears to be the limiting factor for the production of PCL not bonded to the HA structure.


Assuntos
Caproatos/química , Durapatita/química , Lactonas/química , Polímeros/síntese química , Temperatura , Polímeros/química , Porosidade , Espectroscopia de Infravermelho com Transformada de Fourier , Propriedades de Superfície , Termogravimetria , Água/química
10.
J Mater Sci Mater Med ; 16(2): 119-28, 2005 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-15744599

RESUMO

Two bioactive silica-phosphate glasses, AP40 and RKKP, were compared in their behaviour in simulated biological environment. Their chemical composition is practically identical, except that RKKP contains small amounts of amphoteric network-former oxides Ta2O5 and La2O3 (composition in wt% for AP40: beta-Ca3(PO4)2 24.50, SiO2 44.30, CaO 18.60, Na2O 4.60, K2O 0.19, MgO 2.82, CaF2 4.99; RKKP: beta-Ca3(PO4)2 24.23, SiO2 43.82, CaO 18.40, Na2O 4.55, K2O 0.19, MgO 2.79, CaF2 4.94, Ta2O5 0.99, La2O3 0.09). Previous investigations showed a better performance in osteopenic bone for RKKP. To gain more insight into these differences in biological behaviour, the in vitro bioactivity of the glasses was studied by treatment with a continuously replenished Hanks' Balanced Salt Solution (HBSS). The glasses were examined before and after HBSS treatment for 20 and 40 days by X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), X-ray Energy Dispersion (EDX), Raman and IR vibrational spectroscopies. Some slight but notable differences between the two glasses were observed after HBSS treatment. IR and EDX analyses showed that deposits formed on both glasses were composed of a calcium deficient carbonate-apatite; however, the layer formed on RKKP glass was found to be slightly more calcium deficient and thinner. EDX analysis evidenced the presence of a small percentage of F- ions only in the layers formed on the RKKP samples. The differences disclosed, although slight, can contribute to the understanding of the different biological behaviour previously observed.


Assuntos
Materiais Biocompatíveis/química , Líquidos Corporais/química , Substitutos Ósseos/química , Cerâmica/química , Vidro/química , Materiais Biocompatíveis/análise , Materiais Biocompatíveis/classificação , Materiais Biomiméticos/química , Substitutos Ósseos/análise , Cerâmica/análise , Cerâmica/classificação , Teste de Materiais , Propriedades de Superfície
11.
J Biomed Mater Res A ; 68(2): 264-72, 2004 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-14704968

RESUMO

In elderly and osteoporotic patients an age-related loss of osteoinductivity could be the biological cause of implant failure regardless of the high quality of the implanted device. yttria stabilized tetragonal zirconia (YSTZ), either coated with the bioactive glass named RKKP bioglaze (RKKP) or uncoated, was implanted in the distal femurs of sham-operated and ovariectomized female rats. Animals were sacrificed at 30 and 60 days. Histomorphometry and microhardness tests were performed to assess osteointegration rate as well as bone quality around the implants. Significant decreases (p < 0.0005) in trabecular bone volume, BV/TV (41%), trabecular bone surface BS/TV (33%), trabecular thickness Tb.Th (20%), and trabecular number Tb.N (32%), together with a significant increase in trabecular separation Tb.Sp (184%), were found for the osteopenic rats compared with the sham-operated rats. At both experimental times the RKKP coating ensured a better osteointegration rate with higher AI values than the uncoated YSTZ, even when osteopenic rats were used (48% at 30 days and 12% at 60 days). No differences were observed at the bone-biomaterial interfaces for either material when comparing sham-operated with osteopenic rats. The present results demonstrate that the RKKP bioactive glass used as a coating ensures a high osteointegration rate even in osteoporotic bone, which is already visible from postoperative day 30 and is still apparent on day 60.


Assuntos
Doenças Ósseas Metabólicas/terapia , Regeneração Óssea/fisiologia , Substitutos Ósseos/metabolismo , Osso e Ossos/metabolismo , Materiais Revestidos Biocompatíveis , Animais , Doenças Ósseas Metabólicas/cirurgia , Vidro , Ratos , Zircônio
12.
J Clin Pathol ; 56(11): 811-6, 2003 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-14600123

RESUMO

AIMS: The epidemiological and pathological features of Hodgkin lymphoma (HL) are complex. The Epstein-Barr virus (EBV) is consistently associated with a proportion of cases, and these cases are thought to represent a distinct aetiological subgroup of HL. The aim of the present analysis was to determine the age and sex specific incidence of EBV associated and non-associated HL, analysed separately, using data derived from a population based study-the Scotland and Newcastle epidemiological study of Hodgkin's disease (SNEHD). This study also provided a unique opportunity to evaluate accuracy in the current diagnosis and classification of HL. METHODS: SNEHD analysed consecutive cases of HL diagnosed in the study area between 1993 and 1997. Diagnostic biopsy material was retrieved, EBV status of tumours was determined, and histological review was performed. RESULTS: In total, 622 cases were eligible for the study, and EBV studies and histopathological review were performed on biopsy material from 537 and 549 cases, respectively. Accuracy in the overall diagnosis of HL and classification of nodular sclerosis HL was good, but diagnosis of HL in the elderly and classification of other subtypes was less reliable. One third of classic HL cases were EBV associated, and age specific incidence curves for EBV associated and non-associated cases were distinct. CONCLUSIONS: Comparison of age specific incidence curves for EBV associated and non-associated HL supports the hypothesis that these are two distinct aetiological entities. Accuracy in the diagnosis of HL is generally good, but certain subgroups of cases continue to present diagnostic difficulties.


Assuntos
Infecções por Vírus Epstein-Barr/complicações , Doença de Hodgkin/virologia , Adolescente , Adulto , Distribuição por Idade , Idoso , Biópsia , Estudos de Casos e Controles , Inglaterra/epidemiologia , Infecções por Vírus Epstein-Barr/epidemiologia , Feminino , Doença de Hodgkin/epidemiologia , Doença de Hodgkin/patologia , Humanos , Incidência , Masculino , Pessoa de Meia-Idade , Escócia/epidemiologia
13.
J Pathol ; 201(2): 312-8, 2003 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-14517849

RESUMO

Epstein-Barr virus (EBV) is associated with several lymphoid and epithelial human malignancies. The latter include gastric adenocarcinomas, while sporadic colorectal adenocarcinomas (CRCs) have been reported to be EBV-negative. Recently, increased numbers of EBV-infected B lymphocytes have been detected in intestinal mucosal samples affected by ulcerative colitis (UC) and, to a lesser extent, Crohn's disease (CD). Both CRC and colorectal non-Hodgkin's lymphoma (NHL) are recognized complications of inflammatory bowel disease (IBD), but it is unclear to what extent EBV contributes to the development of these neoplasms. Seventeen cases of IBD-associated CRC and nine cases of IBD-associated colorectal NHL were therefore studied for the presence of EBV by in situ hybridization. EBV-positive cases were further studied for the expression of the EBV-encoded nuclear antigen (EBNA) 2 and the latent membrane protein (LMP) 1 of EBV by immunohistochemistry. Four out of seven cases of colorectal NHL associated with UC were shown to be EBV-positive. In addition, two of two colorectal NHLs developing in patients with CD were EBV-positive. Of the EBV-positive lymphomas, three displayed a pattern of EBV latent gene expression consistent with type I latency (EBNA2(-)/LMP1(-)), two a type II pattern (EBNA2(-)/LMP1(+)), and one a type III pattern (EBNA2(+)/LMP1(+)). These findings suggest that EBV infection is involved in the pathogenesis of a proportion of colorectal NHLs developing in IBD. Iatrogenic immunosuppression may contribute to the development of these lymphomas. By contrast, all 17 IBD-associated CRCs were EBV-negative, including a case of CRC occurring synchronously with an EBV-positive NHL. In conjunction with previous reports on sporadic CRCs, this suggests that EBV is not involved in the pathogenesis of CRC.


Assuntos
Neoplasias Colorretais/virologia , Herpesvirus Humano 4/isolamento & purificação , Doenças Inflamatórias Intestinais/virologia , Linfoma de Células B/virologia , Adenocarcinoma/complicações , Adenocarcinoma/virologia , Adulto , Idoso , Colite Ulcerativa/complicações , Colite Ulcerativa/virologia , Colo , Neoplasias Colorretais/complicações , Doença de Crohn/complicações , Doença de Crohn/virologia , Feminino , Humanos , Doenças Inflamatórias Intestinais/complicações , Mucosa Intestinal/virologia , Linfoma de Células B/complicações , Masculino , Pessoa de Meia-Idade
14.
Biomaterials ; 24(1): 147-55, 2003 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-12417188

RESUMO

Recent research suggests that the biocompatibility of an implant is to a large extent determined by selective adsorption of proteins from surrounding body fluids. Protein adsorption from human plasma onto two bioactive glass-ceramics (RKKP and AP40) which differ in La and Ta content, was studied by means of chromatography and two-dimensional polyacrylamide gel electrophoresis (2D-PAGE). The quantitative analysis showed that the glass-ceramics have good protein binding capacities indicating multilayer formation. A correlation between chemical composition and the amount of adsorbed proteins was observed. The presence of La and Ta decreased the protein adsorption, so AP40 bound significantly more protein per surface unit then did RKKP. Preferential adsorption of apolipoprotein J, fibrinogen and fibronectin was observed.


Assuntos
Proteínas Sanguíneas/farmacocinética , Cerâmica , Adsorção , Cerâmica/química , Clusterina , Fibrinogênio/farmacocinética , Fibronectinas/farmacocinética , Glicoproteínas/farmacocinética , Humanos , Técnicas In Vitro , Teste de Materiais , Chaperonas Moleculares/farmacocinética , Ligação Proteica , Propriedades de Superfície , Vitronectina/farmacocinética
15.
Biomaterials ; 23(18): 3833-41, 2002 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-12164187

RESUMO

Osteointegration of yttria stabilised tetragonal zirconia (YSTZ), either coated with bioactive glass named RKKP bioglaze (RKKP) or uncoated, was evaluated in an animal model. RKKP-coated and uncoated (controls) YSTZ cylinders were implanted in the distal femoral epiphyses of 14 Sprague Dawley rats under general anaesthesia. At the experimental times of 30 and 60 days after sacrifice, histomorphometry and SEM microanalysis were performed on methylmethacrylate-embedded undecalcified sections to determine the osteointegration rate. At 30 days, a significantly higher affinity index was demonstrated in vivo by histomorphometric evaluation in RKKP-coated versus uncoated YSTZ implants p < 0.05); at 60 days, the coated implants behaved better than controls (affinity index of + 32%), but the difference observed lay within the statistical uncertainty. SEM analysis demonstrated better bone adhesion to the material in RKKP-coated YSTZ at both 30 and 60 days. These findings suggest that YSTZ coated with the bioactive glass named RKKP enhances osteointegration of ceramics.


Assuntos
Materiais Biocompatíveis , Materiais Revestidos Biocompatíveis , Fêmur/metabolismo , Vidro , Zircônio , Adsorção , Animais , Linhagem Celular , Feminino , Fêmur/ultraestrutura , Microscopia Eletrônica de Varredura , Próteses e Implantes , Ratos , Ratos Sprague-Dawley , Espalhamento de Radiação , Fatores de Tempo , Aderências Teciduais , Ítrio/metabolismo
16.
J Biomed Mater Res ; 61(2): 282-9, 2002 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-12007209

RESUMO

The biocompatibility and osseointegration of zirconia (ZrO(2)), either coated with RKKP bioglazeor uncoated, were evaluated in vitro and in vivo. The in vitro test was performed in human osteoblasts, whereas maximal sensitization was performed in 23 Dunkin Hurtley guinea pigs. RKKP bioglaze-coated and uncoated (controls) ZrO(2) cylinders were implanted in the distal femoral epiphyses of 14 Sprague-Dawley rats under general anesthesia, and animals were sacrificed at 30 and 60 days. Lactate dehydrogenase, alkaline phosphatase, and Thiazolyl Blue (MTT) were tested in vitro. A graded score was used for evaluating the results of the sensitization test. Histomorphometry and microhardness testing were performed to quantify the osseointegration rate, as well as bone quality around the implants. Neither in vitro cytotoxicity nor sensitization were observed. Histomorphometry demonstrated that at 30 days, the affinity index was significantly higher in coated implants than in uncoated ones (p < 0.05); at 60 days, the behavior of coated implants was better than that of uncoated ones, but differences were not significant. Significant increases in bone microhardness were found at 1000 microm from the interface area for both uncoated (p < 0.0005) and RKKP bioglaze-coated (p < 0.0005) ZrO(2), and also within 200 microm from the interface (p = 0.014) but only for coated ZrO(2.) These results suggest that RKKP bioglaze-coated ZrO(2) permits biocompatible devices with improved osseointegration properties to be manufactured.


Assuntos
Materiais Revestidos Biocompatíveis/normas , Teste de Materiais , Osseointegração , Zircônio/normas , Animais , Substitutos Ósseos/normas , Morte Celular/efeitos dos fármacos , Cerâmica , Materiais Revestidos Biocompatíveis/farmacologia , Materiais Revestidos Biocompatíveis/toxicidade , Feminino , Cobaias , Humanos , Imunização , Implantes Experimentais/normas , Mecânica , Osteoblastos/efeitos dos fármacos , Ratos , Taxa de Sobrevida , Zircônio/farmacologia , Zircônio/toxicidade
17.
Biomaterials ; 23(4): 1237-47, 2002 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-11791928

RESUMO

The protein/biomaterial interactions of three biomaterials used in hard tissue surgery were studied in vitro. A dynamic flow system and two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) were used to investigate the adsorption of proteins from diluted human plasma on hydroxyapatite, alumina and zirconia, with regard to total protein binding capacity, relative binding capacity for specific proteins and flow-through and desorption patterns. The ceramics were characterized regarding physicochemical properties; namely, chemical composition by elementary analyses and specific surface, pore volume and pore size distribution using the BET-method and Hg-porosimetry. The materials were found to adsorb a surprisingly low amount of plasma proteins, leaving more than 70% of the surface free. The cellular response will therefore be highly affected by the physico-chemical properties of the material, in contrast to a surface fully covered with proteins. Regarding the adsorption of proteins, most proteins exhibited similar flow-through patterns on the three adsorbents. The exceptions with different flow-through patterns were apolipoprotein D (Apo D), apolipoprotein J (Apo J), complement factor C1s (C1s), complement factor C3 (C3), ceruloplasmin, fibrinogen, alpha1 B glycoprotein and alpha2 HS glycoprotein and serum retinal-binding protein (SRBP). The role of these proteins on acceptance or rejection of implants has to be investigated.


Assuntos
Proteínas Sanguíneas/metabolismo , Cerâmica , Adsorção , Óxido de Alumínio , Durapatita , Eletroforese em Gel Bidimensional , Fibronectinas/metabolismo , Humanos , Imunoglobulina G/metabolismo , Técnicas In Vitro , Teste de Materiais , Ligação Proteica , Albumina Sérica/metabolismo , Propriedades de Superfície , Vitronectina/metabolismo , Zircônio
18.
Biomaterials ; 22(18): 2535-43, 2001 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-11516086

RESUMO

ZrO2 and Al2O3 substrates were successfully coated by a double layer of a silica-based glass named RKKP, using a low-cost firing technique. RKKP is a glass well known for its bioactivity; therefore, a RKKP coating on Al2O3 or ZrO2, allows to combine the excellent mechanical properties of these strong ceramic substrates with its bioactivity. ZrO2 samples were easily coated using a double layer of RKKP by a simple enamelling technique. To accommodate the thermal expansion coefficient mismatch between Al2O3 and RK K P, this substrate was coated using a multilayered composite approach. All of the coatings were characterised from a morphological and compositional point of view, and an extensive biological evaluation was performed using fresh rat osteoblasts. Osteoblast primary cultures were derived from the trabecular bone of femoral condyles harvested from intact (NB) and osteopenic (OB) rats. After characterisation of their phenotype, osteoblasts were seeded on material samples of ZrO2 or Al2O3 coated with RKKP, and cultured for 7 days. Cell proliferation (MTT test) and cell differentiation (alkaline phosphatase activity) were evaluated at the end of the experiment, to assess osteoblast behaviour in the presence of biomaterials and determine if the results were related to the host bone quality. Results of both materials showed a good level of biocompatibility. In particular, MTT significant higher values were detected in NB cultures on ZrO2-RKKP samples; ALP activity significantly increased in NB cultures on Al2O3-RKKP and in OB cultures on both coated samples.


Assuntos
Materiais Biocompatíveis , Doenças Ósseas Metabólicas/patologia , Cerâmica , Materiais Revestidos Biocompatíveis , Osteoblastos/citologia , Óxido de Alumínio , Animais , Doenças Ósseas Metabólicas/cirurgia , Adesão Celular , Divisão Celular , Células Cultivadas , Teste de Materiais , Próteses e Implantes , Ratos , Zircônio
19.
J Bone Joint Surg Br ; 83(1): 139-43, 2001 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-11245523

RESUMO

We implanted nails made of titanium (Ti6Al4V) and of two types of glass ceramic material (RKKP and AP40) into healthy and osteopenic rats. After two months, a histomorphometric analysis was performed and the affinity index calculated. In addition, osteoblasts from normal and osteopenic bone were cultured and the biomaterials were evaluated in vitro. In normal bone the rate of osseointegration was similar for all materials tested (p < 0.5) while in osteopenic bone AP40 did not osseointegrate (p < 0.0005). In vitro, no differences were observed for all biomaterials when cultured in normal bone-derived cells whereas in osteopenic-bone-derived cells there was a significant difference in some of the tested parameters when using AP40. Our findings suggest that osteopenic models may be used in vivo in the preclinical evaluation of orthopaedic biomaterials. We suggest that primary cell cultures from pathological models could be used as an experimental model in vitro.


Assuntos
Pinos Ortopédicos , Teste de Materiais , Osseointegração/fisiologia , Osteoporose/patologia , Ligas , Animais , Cerâmica , Feminino , Fêmur/patologia , Ratos , Ratos Sprague-Dawley , Titânio
20.
Biomaterials ; 21(8): 765-73, 2000 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-10721745

RESUMO

In order to combine the mechanical properties of a high-strength inert ceramic (yttria-stabilised zirconia, ZrO2-3%Y2O3, defined as zirconia in the text) with the specific properties of bioactive materials, some zirconia samples were coated by two bioactive phosphosilicate glasses and glass-ceramics: RKKP and AP40. Coatings of about 200-300 microm thickness were prepared by a simple and low-cost firing method. They were characterised by optical and scanning electron microscopy (SEM) and compositional analysis (EDS). The adhesion of the coatings on zirconia was tested by shear tests. Vickers indentations at the coating/zirconia interface were performed in order to observe the crack propagation path. The reactivity of glasses and glass-ceramics coatings towards a simulated body fluid (SBF), having the same ion concentration as that of human plasma, was evaluated and compared to that of the bulk glass and glass-ceramics, by examining the morphology of the reaction layer formed on the surface of the coated zirconia after one month of soaking in the SBF at 37 degrees C.


Assuntos
Materiais Biocompatíveis , Zircônio , Líquidos Corporais , Cerâmica , Vidro , Humanos , Técnicas In Vitro , Teste de Materiais , Microscopia Eletrônica de Varredura , Propriedades de Superfície
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