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1.
Folia Morphol (Warsz) ; 82(1): 119-126, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-34966995

RESUMO

BACKGROUND: In our study we used immunohistochemical technique to demonstrate the presence of the cytokines tumour necrosis factor alpha (TNF-α), interleukin 1beta (IL-1ß), transforming growth factor beta1 (TGF-ß1) and intercellular adhesion molecule-1 (ICAM-1) in porcine coronaries even in physiological conditions. MATERIALS AND METHODS: Inflammatory cytokines are polypeptide mediators which act as a communication signal between immune system cells and other types of cellsin different organs and tissues, both in human and pig coronary circulation. RESULTS: Our results show that pro-inflammatory cytokines TNF-α, IL-1ß, TGF-ß1 and ICAM-1 are also present in the medium tunica of the coronary arteries under physiological conditions. These results may be compared with those found in coronary atherosclerosis, where the increase in TNF-α has a dramatic effect on the function of the left ventricle, and the high value of IL-1 correlates directly with the extent of myocardial necrosis. In our study we observe the damage and activation of endothelial cells; this induces endothelial dysfunction by accumulation and oxidation of low density lipoproteins (LDL). The formation of oxidized LDL could play a central role in the amplification of the inflammatory response causing an increased expression of pro-inflammatory cytokines which promotes leukocyte recruitment in the intimal layer. These leukocytes, after the adhesion to the endothelium, penetrate the intimate tunic. CONCLUSIONS: Therefore inflammatory processes promote the onset and evolution of atheroma and the development of thrombotic complications.


Assuntos
Fator de Crescimento Transformador beta1 , Fator de Necrose Tumoral alfa , Humanos , Suínos , Animais , Fator de Necrose Tumoral alfa/metabolismo , Fator de Crescimento Transformador beta1/metabolismo , Fator de Crescimento Transformador beta1/farmacologia , Molécula 1 de Adesão Intercelular/metabolismo , Molécula 1 de Adesão Intercelular/farmacologia , Interleucina-1beta/metabolismo , Interleucina-1beta/farmacologia , Células Endoteliais/metabolismo , Vasos Coronários , Citocinas
2.
Int J Food Microbiol ; 284: 91-97, 2018 Nov 02.
Artigo em Inglês | MEDLINE | ID: mdl-30081345

RESUMO

Selective pressure in the aquatic environment of intensive fish farms leads to acquired antibiotic resistance. This study used the broth microdilution method to measure minimum inhibitory concentrations (MICs) of 15 antibiotics against 104 Aeromonas spp. strains randomly selected among bacteria isolated from Sparus aurata reared in six Italian mariculture farms. The antimicrobial agents chosen were representative of those primarily used in aquaculture and human therapy and included oxolinic acid (OXA), ampicillin (AM), amoxicillin (AMX), cephalothin (CF), cloramphenicol (CL), erythromycin (E), florfenicol (FF), flumequine (FM), gentamicin (GM), kanamycin (K), oxytetracycline (OT), streptomycin (S), sulfadiazine (SZ), tetracycline (TE) and trimethoprim (TMP). The most prevalent species selected from positive samples was Aeromonas media (15 strains). The bacterial strains showed high resistance to SZ, AMX, AM, E, CF, S and TMP antibiotics. Conversely, TE and CL showed MIC90 values lower than breakpoints for susceptibility and many isolates were susceptible to OXA, GM, FF, FM, K and OT antibiotics. Almost all Aeromonas spp. strains showed multiple antibiotic resistance. Epidemiological cut-off values (ECVs) for Aeromonas spp. were based on the MIC distributions obtained. The results showed a high frequency of Aeromonas spp. contamination in Sparus aurata reared on the Italian coast and an elevated biodiversity in isolated bacterial strains. Aeromonas isolates comprise potentially pathogenic species for humans, often resistant to several antibiotics and able to transfer the genes responsible for antibiotic resistance to microorganisms pathogenic for humans throughout the food chain. The few ECV studies available on many antibiotics against Aeromonas spp. strains isolated from the aquaculture environment highlight the need for further research in this area, while regular monitoring programmes should be stepped up to check for antibiotic resistance.


Assuntos
Aeromonas/efeitos dos fármacos , Antibacterianos/farmacologia , Farmacorresistência Bacteriana Múltipla/genética , Dourada/microbiologia , Aeromonas/genética , Aeromonas/isolamento & purificação , Animais , Eritromicina/farmacologia , Pesqueiros , Fluoroquinolonas/farmacologia , Humanos , Itália , Testes de Sensibilidade Microbiana , Tetraciclina/farmacologia
3.
Food Microbiol ; 74: 50-56, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-29706337

RESUMO

Ricotta fresca is a whey cheese susceptible of secondary contamination, mainly from Pseudomonas spp. The extension of the shelf life of refrigerated ricotta fresca could be obtained using protective cultures inhibiting the growth of this spoilage microorganism. A commercial biopreservative, Lyofast CNBAL, comprising Carnobacterium spp was tested against Pseudomonas spp. The surface of ricotta fresca samples were inoculated either with Pseudomonas spp or Pseudomonas and Carnobacterium spp. Samples were MAP packed, stored at 4 °C and analyzed the day of the inoculum and 7, 14 and 21 days after the contamination. Microbiological analyses included total bacterial count, mesophilic lactic acid bacteria, Enterobacteriaceae, Pseudomonas spp, Listeria monocytogenes, moulds and yeasts. Pseudomonas mean initial contamination level was comparable in blank and artificially inoculated samples, respectively with values of 2.15 ±â€¯0.21 and 2.34 ±â€¯0.26 log cfu g-1. Carnobacterium spp. significantly reduced the growth of Pseudomonas spp respectively of 1.28 log and 0.83 log after 14 and 21 days of refrigerated storage. Intrinsic properties and physico-chemical composition were also investigated. Limited variation of pH was observed in samples inoculated with the protective cultures, indicating low acidification properties of Carnobacterium spp. Instead, no significant differences were observed for aW, moisture, fat and proteins during storage and between inoculated and control samples.


Assuntos
Antibiose , Carnobacterium/fisiologia , Queijo/microbiologia , Microbiologia de Alimentos , Conservação de Alimentos/métodos , Pseudomonas/crescimento & desenvolvimento , Animais , Queijo/análise , Contagem de Colônia Microbiana , Enterobacteriaceae/crescimento & desenvolvimento , Contaminação de Alimentos/análise , Contaminação de Alimentos/prevenção & controle , Manipulação de Alimentos , Qualidade dos Alimentos , Fungos/crescimento & desenvolvimento , Gases/análise , Concentração de Íons de Hidrogênio , Lactobacillales/crescimento & desenvolvimento , Listeria monocytogenes/crescimento & desenvolvimento , Leite/microbiologia , Refrigeração , Ovinos , Temperatura , Fatores de Tempo
4.
Food Microbiol ; 66: 72-76, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28576375

RESUMO

Ricotta fresca cheese is susceptible to secondary contamination and is able to support the growth of pathogens or spoilage psychotrophic bacteria during storage. The aim of the present study was to evaluate which among three commercial biopreservatives was suitable to be used to control the growth of spoilage microorganisms in sheep's milk MAP ricotta fresca cheese. 144 Ricotta fresca cheese samples were inoculated either with the bioprotective culture Lyofast FPR 2 (including Enterococcus faecium, Lactobacillus plantarum e Lactobacillus rhamnosus) or Lyofast CNBAL (Carnobacterium spp) or the fermentate MicroGARD 430. Not inoculated control and experimental ricotta were MAP packed (30% CO2 and 70% N2) and stored at 4 °C. Triplicate samples were analyzed after 5 h and 7, 14 and 21 days after inoculation for total bacterial count, mesophilic lactic acid bacteria, Enterobacteriaceae, Pseudomonas spp, Listeria monocytogenes, moulds and yeasts. Among the tested biopreservatives only Carnobacterium spp was able to control Pseudomonas spp and Enterobacteriaceae. The maximum reduction in the concentration of Pseudomonas spp and Enterobacteriaceae was respectively 1.93 and 2.66 log10 cfu/g, observed 14 days after production. Therefore, Carnobacterium spp was selected as the culture of choice to conduct a challenge study against Pseudomonas spp.


Assuntos
Antibiose , Queijo/microbiologia , Conservação de Alimentos/métodos , Lactobacillaceae/fisiologia , Animais , Queijo/economia , Enterobacteriaceae/crescimento & desenvolvimento , Contaminação de Alimentos/análise , Contaminação de Alimentos/economia , Contaminação de Alimentos/prevenção & controle , Microbiologia de Alimentos/economia , Conservação de Alimentos/economia , Listeria monocytogenes/crescimento & desenvolvimento , Leite/microbiologia , Ovinos
5.
Org Biomol Chem ; 14(48): 11371-11380, 2016 Dec 07.
Artigo em Inglês | MEDLINE | ID: mdl-27805236

RESUMO

We describe the qualitative and quantitative analysis of the complexation properties towards cations of a cyclic peptoid hexamer composed of alternating α- and ß-peptoid monomers, which bear exclusively chiral (S)-phenylethyl side chains (spe) that have no noticeable chelating properties. The binding of a series of monovalent and divalent cations was assessed by 1H NMR, circular dichroism, fluorescence and molecular modelling. In contrast to previous studies on cations binding by 18-membered α-cyclopeptoid hexamers, the 21-membered cyclopeptoid cP1 did not complex monovalent cations (Na+, K+, Ag+) but showed selectivity for divalent cations (Ca2+, Ba2+, Sr2+ and Mg2+). Hexacoordinated C-3 symmetrical complexes were demonstrated for divalent cations with ionic radii around 1 Å (Ca2+ and Ba2+), while 5-coordination is preferred for divalent cations with larger (Ba2+) or smaller ionic radii (Mg2+).


Assuntos
Peptoides/química , Cátions Bivalentes/química , Dicroísmo Circular , Fluorescência , Modelos Moleculares , Estrutura Molecular , Espectroscopia de Prótons por Ressonância Magnética
6.
J Appl Microbiol ; 120(1): 165-74, 2016 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-26481316

RESUMO

AIMS: The present study aimed to determine, by multilocus sequence type (MLST), the heterogeneity level of Arcobacter butzleri isolates and to compare MLST and pulsed-field gel electrophoresis (PFGE) in terms of discriminatory power (DI) as well as unidirectional and bi-directional concordance. METHODS AND RESULTS: Arcobacter butzleri isolates (N = 133) from dairy products and environmental samples, collected from dairy plants, were characterized by MLST and PFGE with SacII and classified in 29 sequence types (STs), 47 PFGE and 62 type strains (TS). Among the 119 alleles, 19 were previously unreported and the same for all the STs but two. A significant linkage disequilibrium was detected when the complete ST data set was analysed The DIs of MLST, PFGE and their combination were 0·937, 0·953 and 0·965 respectively. The adjusted Wallace coefficients between MLST and PFGE as well as PFGE and MLST were 0·535 and 0·720 respectively; the adjusted Rand coefficient was 0·612. CONCLUSIONS: The A. butzleri studied population showed recombination to some degree. PFGE showed a DI higher than MLST. Both methods presented good concordance. The TS analysis seems to show persistence of the same strain on time and possible cross-contaminations between food and environmental sites. SIGNIFICANCE AND IMPACT OF THE STUDY: This study provides insights in the A. butzleri population found in raw milk, cheese, and dairy production plants. The data suggest that MLST and PFGE genotypes correlate reasonably well, although their combination results in optimal resolution.


Assuntos
Arcobacter/isolamento & purificação , Técnicas de Tipagem Bacteriana/métodos , Laticínios/microbiologia , Eletroforese em Gel de Campo Pulsado/métodos , Tipagem de Sequências Multilocus/métodos , Alelos , Arcobacter/classificação , Arcobacter/genética , Manipulação de Alimentos/instrumentação , Genótipo
7.
Arq. gastroenterol ; 52(4): 315-320, Oct.-Dec. 2015. tab
Artigo em Inglês | LILACS | ID: lil-771919

RESUMO

Background - Different factors are responsible for the progression of hepatic fibrosis in chronic infection with hepatitis C virus, but the role of nutritional factors in the progression of the disease is not clearly defined. This study aimed to evaluate the nutritional status and dietary profile among patients with chronic hepatitis C who were candidates for treatment and its association with histopathological features. Methods - A crossectional study was conducted on treatment-naïve patients with chronic hepatitis C genotype 1, between 2011 and 2013. The following assessments were performed before treatment: liver biopsy, anthropometric measurements and qualitative/quantitative analysis of food intake. Results - Seventy patients were studied. The majority of patients was classified as obese (34%) or overweight (20%) according to body mass index [BMI] and as at risk for cardiovascular diseases by waist circumference (79%). Unhealthy food intake was presented by 59% according to qualitative parameters and several patients showed an insufficient intake of calories (59%), excessive intake of protein (36%) and of saturated fat (63%), according to quantitative analysis. With respect to histology, 68% presented activity grade ≥2, 65% had steatosis and 25% exhibited fibrosis stage >2. Comparative analysis between anthropometric parameters and histological features showed that elevated waist circumference was the only variable associated to hepatic steatosis ( P =0.05). There was no association between qualitative and quantitative food intake parameters with histological findings. Conclusion - In this study, most of the patients with hepatitis C presented inadequate qualitative food intake and excessive consumption of saturated fat; in addition, excess of abdominal fat was associated to hepatic steatosis. Therefore, nutritional guidance should be implemented prior to treatment in patients with chronic hepatitis C, in order to avoid nutritional disorders and negative impact on the management of patients.


Contexto - Diferentes fatores são responsáveis pela progressão da fibrose na infecção crônica pelo vírus da hepatite C, mas o papel dos fatores nutricionais na progressão da doença não está definido. Este estudo teve como objetivo avaliar o estado nutricional e o perfil dietético de pacientes com hepatite C crônica candidatos a tratamento e sua associação com achados histopatológicos. Métodos - Foi conduzido um estudo transversal em pacientes com hepatite C crônica genótipo 1 virgens de tratamento, entre 2011 e 2013. Foram analisados, antes do tratamento, os seguintes aspectos: biópsia hepática, medidas antropométricas e análise qualitativa e quantitativa do consumo alimentar. Resultados - Setenta pacientes foram estudados. A maioria dos pacientes apresentava obesidade (34%) ou sobrepeso (20%) de acordo com índice de massa corporal e risco para doenças cardiovasculares de acordo com a circunferência da cintura elevada (79%). Na análise qualitativa do consumo alimentar, 59% apresentavam uma dieta inadequada. Conforme análise quantitativa, 59% tinham consumo insuficiente de calorias, 36% consumo excessivo de proteínas e 63% consumo excessivo de gorduras saturadas. Com relação à histologia, 68% apresentavam grau de atividade inflamatória ≥2, 65% mostraram esteatose hepática e 25% possuíam grau de fibrose >2. Na análise comparativa entre as medidas antropométricas e achados histológicos, somente a circunferência da cintura elevada mostrou associação com esteatose hepática ( P =0,05). Não houve associação entre consumo alimentar qualitativo e quantitativo com parâmetros histológicos. Conclusão - A maioria dos pacientes apresentava consumo alimentar inadequado de acordo com parâmetros qualitativos e consumo excessivo de gordura saturada, além de excesso de gordura abdominal, que esteve associada à esteatose hepática. Portanto, aconselhamento nutricional deveria ser implementado em pacientes candidatos a tratamento para hepatite C crônica visando evitar distúrbios nutricionais que podem impactar negativamente no manejo dos pacientes.


Assuntos
Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Ingestão de Energia/fisiologia , Comportamento Alimentar/fisiologia , Hepatite C Crônica/complicações , Índice de Massa Corporal , Doença Crônica , Estudos Transversais , Progressão da Doença , Fígado Gorduroso/etiologia , Fígado Gorduroso/fisiopatologia , Genótipo , Hepatite C Crônica/genética , Hepatite C Crônica/fisiopatologia , Cirrose Hepática/etiologia , Cirrose Hepática/fisiopatologia , Obesidade/complicações , Obesidade/fisiopatologia , Fatores de Risco , Índice de Gravidade de Doença
8.
Arq Gastroenterol ; 52(4): 315-20, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26840474

RESUMO

BACKGROUND: Different factors are responsible for the progression of hepatic fibrosis in chronic infection with hepatitis C virus, but the role of nutritional factors in the progression of the disease is not clearly defined. This study aimed to evaluate the nutritional status and dietary profile among patients with chronic hepatitis C who were candidates for treatment and its association with histopathological features. METHODS: A crossectional study was conducted on treatment-naïve patients with chronic hepatitis C genotype 1, between 2011 and 2013. The following assessments were performed before treatment: liver biopsy, anthropometric measurements and qualitative/quantitative analysis of food intake. RESULTS: Seventy patients were studied. The majority of patients was classified as obese (34%) or overweight (20%) according to body mass index [BMI] and as at risk for cardiovascular diseases by waist circumference (79%). Unhealthy food intake was presented by 59% according to qualitative parameters and several patients showed an insufficient intake of calories (59%), excessive intake of protein (36%) and of saturated fat (63%), according to quantitative analysis. With respect to histology, 68% presented activity grade ≥2, 65% had steatosis and 25% exhibited fibrosis stage >2. Comparative analysis between anthropometric parameters and histological features showed that elevated waist circumference was the only variable associated to hepatic steatosis ( P =0.05). There was no association between qualitative and quantitative food intake parameters with histological findings. CONCLUSION: In this study, most of the patients with hepatitis C presented inadequate qualitative food intake and excessive consumption of saturated fat; in addition, excess of abdominal fat was associated to hepatic steatosis. Therefore, nutritional guidance should be implemented prior to treatment in patients with chronic hepatitis C, in order to avoid nutritional disorders and negative impact on the management of patients.


Assuntos
Ingestão de Energia/fisiologia , Comportamento Alimentar/fisiologia , Hepatite C Crônica/complicações , Índice de Massa Corporal , Doença Crônica , Estudos Transversais , Progressão da Doença , Fígado Gorduroso/etiologia , Fígado Gorduroso/fisiopatologia , Feminino , Genótipo , Hepatite C Crônica/genética , Hepatite C Crônica/fisiopatologia , Humanos , Cirrose Hepática/etiologia , Cirrose Hepática/fisiopatologia , Masculino , Pessoa de Meia-Idade , Obesidade/complicações , Obesidade/fisiopatologia , Fatores de Risco , Índice de Gravidade de Doença
9.
Int J Immunopathol Pharmacol ; 25(1): 117-25, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22507324

RESUMO

Pituitary adenomas are a diverse group of tumors arising from the pituitary gland. Typically, they are small, slow-growing, hormonally inactive lesions that come to light as incidental findings on radiologic or postmortem examinations, although some small, slow-growing lesions with excessive hormonal activity may manifest with a clinical syndrome. The family of neurotrophins plays a key role in the development and maintenance of the pituitary endocrine cell function and in the regulation of hypothalamo-pituitary-adrenocortical axis activity. The objective of our experimental study is to investigate the localization of the neurotrophins, their relative receptors and to detect the expression level of Ki-67 to determine whether all these factors participate in the transformation and development of human pituitary adenomas. A very strong expression of Neurotrophin-3 (NT-3) and its receptor TrKC was observed in the extracellular matrix (ECM) and vessel endothelium, together with a clear/marked presence of Brain-derived neurotrophic factor (BDNF), and its receptor TrKB, thus confirming their direct involvement in the progression of pituitary adenomas. On the contrary, NGF (Nerve growth factor) and its receptor TrKA and p75NTR were weakly expressed in the epithelial gland cells and the ECM.


Assuntos
Adenoma/química , Adenoma Hipofisário Secretor de Hormônio do Crescimento/química , Antígeno Ki-67/análise , Fatores de Crescimento Neural/análise , Matriz Extracelular/química , Humanos , Imuno-Histoquímica , Proteínas do Tecido Nervoso/análise , Receptor trkA/análise , Receptor trkB/análise , Receptor trkC/análise , Receptores de Fator de Crescimento Neural/análise
10.
Food Chem Toxicol ; 50(5): 1413-7, 2012 May.
Artigo em Inglês | MEDLINE | ID: mdl-22293285

RESUMO

Concentrations of 7 polychlorinated dibenzo-p-dioxins (PCDDs), 10 polychlorinated dibenzofurans (PCDFs) and 22 polychlorinated biphenyls (PCBs), including 12 dioxin like-PCBs (non- and mono-ortho PCBs) were measured in 80 sheep milk samples from farms located in an industrialized area of Sardinia, Italy. PCDDs and PCDFs mean concentrations were 2.45 and 3.69 pgg(-1) fat basis, respectively. The mean dl-PCB concentration was 2.01 ngg(-1) fat basis, while cumulative ndl-PCB levels ranged from 1.02 to 20.42, with a mean of 4.92 ngg(-1) fat. The results expressed in pg WHO-TEQ/g fat showed that contamination level of milk was below the limit values for human consumption established by EC legislation. In the same way, all the investigated milk exhibited PCDD/Fs concentrations below EU action levels, while dl-PCBs concentrations exceeded the action level of 2.0 pg WHO-TEQ/g fat. These findings point to the need to continue to conduct general monitoring programmes, including also milk samples from areas not close to the contaminant-emitting industries, in order to better evaluate the impact of industrial activities on surrounding environment.


Assuntos
Benzofuranos/análise , Indústrias , Leite/química , Bifenilos Policlorados/análise , Dibenzodioxinas Policloradas/análogos & derivados , Animais , Dibenzofuranos Policlorados , Cromatografia Gasosa-Espectrometria de Massas , Itália , Dibenzodioxinas Policloradas/análise , Controle de Qualidade , Ovinos
12.
Vet Res Commun ; 34 Suppl 1: S87-90, 2010 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-20437273

RESUMO

In vitro activities of 16 antibiotics were tested against 36 Staphylococcus aureus (SA) strains isolated from raw sheep's milk cheese from six dairies. The minimum inhibitory concentration (MIC) was determined using a broth microdilution method (CLSI). All 36 isolates were analyzed for the presence of the accessory gene regulator gene, agr (I-IV), and genes encoding resistance to methicillin (mecA), erythromycin (ermA), penicillin (blaZ), and vancomycin (vanA-B). The isolates were also analyzed for similarities in pulsed-field gel electrophoresis (PFGE) patterns. SA strains showed resistance to ampicillin (36.1%), penicillin (33.3%), tetracycline (11.1%), and cloxacillin (2.8%) but were susceptible (>or=94.4%) to 12 out of 16 tested antimicrobials. The overall susceptibility of the strains to oxacillin, vancomycin, and erythromycin was confirmed by the absence of the mecA, vanA-B, and ermA genes. The PFGE results showed that 32 strains belonged to 10 different clusters (P1-P10) while four strains were untypeable.


Assuntos
Antibacterianos/farmacologia , Queijo/microbiologia , Farmacorresistência Bacteriana Múltipla , Microbiologia de Alimentos , Leite/microbiologia , Staphylococcus aureus/efeitos dos fármacos , Animais , Testes de Sensibilidade Microbiana , Ovinos
17.
Meat Sci ; 69(4): 733-9, 2005 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-22063151

RESUMO

Lactic acid bacteria (LAB) were isolated during the production and the ripening of Sardinian sausage, a typical Italian dry fermented sausage. Samples were taken at different stages, and 112 strains were isolated. The isolates were characterized using the micromethod proposed by Font de Valdez et al. [Font de Valdez, G., Savoy de Giori, G., Oliver, G., & De Ruiz Holgado, A. P. (1993). Development and optimization of an expensive microsystem for the biochemical characterization of lactobacilli. Microbiologie Aliments Nutrition, 11, 215-219]. Schillinger and Lücke's [Schillinger, U., & Lücke, F. K. (1987). Identification of lactobacilli from meat and meat products. Food Microbiology. (4), 199-208] scheme and the biochemical patterns given by Bergey's Manual of Systematic Bacteriology [Bergey's Manual of Systematic Bacteriology (1986). Baltimore: William and Wilkins] were used for preliminary identification. A PCR-based method was then used to confirm the results. LAB were the dominant flora during ripening. They consisted mainly of homofermentative mesophilic rods. Lactobacillus sakei (43,3%), Lactobacillus plantarum (16,6%) and Lactobacillus curvatus (13,3%) were the main isolates. The results of the biochemical identification methods agreed well with those of PCR-based identification (91% agreement).

18.
J Bone Joint Surg Br ; 86(8): 1192-6, 2004 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-15568536

RESUMO

We studied factors contributing to the initiation of fracture and failure of a zirconia ceramic femoral head. The materials retrieved during a revision total hip replacement were submitted to either visual, stereomicroscopic and scanning electron microscopy (SEM) or SEM and energy-dispersive X-ray analysis. X-ray diffraction was performed in order to investigate the extent of tetragonal to monoclinic phase transition. Histological examination was performed on the periprosthetic tissues. The results showed that failure was due to the propagation during clinical use of defects which may have been introduced into the material during the processing of the ceramic, rather than those intrinsic to zirconia. The literature relating to previous failures of zirconia components is reviewed.


Assuntos
Cerâmica , Prótese de Quadril , Osteoartrite do Quadril/cirurgia , Falha de Prótese , Humanos , Masculino , Pessoa de Meia-Idade , Osteoartrite do Quadril/diagnóstico por imagem , Osteoartrite do Quadril/patologia , Radiografia , Difração de Raios X
20.
Int Orthop ; 27(5): 272-7, 2003.
Artigo em Inglês | MEDLINE | ID: mdl-12811523

RESUMO

Sixteen 2- to 3-year-old sheep were submitted to a hemiarthroplasty of the hip joint with a specially designed femoral component. The proximal two thirds of the stem had a circumferential, plasma-sprayed, porous coating with hydroxyapatite. The animals where killed a 15, 30, 60, 90, 120, 180, 200, 270, 360, and 540 days after surgery. Femurs were submitted to plain radiographs, computerised tomography (CT) scan, and dual energy X-ray absorptiometry (DEXA). Cross-sections were obtained at four different levels and studied using scanning electron microscopy. In the coated portion of the stem, apposition of woven immature bone was evident at 15-30 days and mature lamellar bone by 30 days. With time, the gap between the endosteum and the coated surface was filled by bridges of lamellar bone with a marked trabecular orientation. In the distal uncoated portion of the stem, the implant was initially surrounded by fibrous tissue that, with time, transformed into lamellar bone.


Assuntos
Materiais Biocompatíveis/farmacologia , Durapatita/farmacologia , Prótese de Quadril , Osseointegração/efeitos dos fármacos , Animais , Artroplastia de Quadril/instrumentação , Articulação do Quadril/fisiologia , Modelos Animais , Osseointegração/fisiologia , Ovinos , Suporte de Carga
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