RESUMO
OBJECTIVE: There is a need to identify reliable biomarkers that can predict knee osteoarthritis (OA) progression. We investigated a panel of adipokines and some related inflammatory factors alone and their ratios for their associative value at assessing cartilage volume loss over time and symptoms in obese [High body mass index (BMI)] and non-obese (Low BMI) OA subjects. DESIGN: Human OA serum was from the Osteoarthritis Initiative Progression subcohort. Baseline levels of adiponectin (high and low molecular weight forms), adipsin, chemerin, leptin, visfatin, C-reactive protein (CRP), interleukin-8 (IL-8) and monocyte chemoattractant protein-1 (MCP-1) were evaluated with specific assays. Cartilage volume was assessed at baseline and 48 months by quantitative magnetic resonance imaging (MRI), and symptoms using baseline Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores. Data were analysed by linear regression with confounding factors at baseline, followed by multiple comparison adjustment. RESULTS: The levels of the nine biomarkers and their ratios (36) were studied. Among High BMI subjects, only the ratio adipsin/MCP-1 was associated with cartilage volume loss over time in the lateral compartment [ß, -2.95; 95% confidence interval (CI), -4.42, -1.49; P = 0.010], whereas MCP-1 was associated with WOMAC pain (-1.74; -2.75, -0.73; P = 0.030) and the ratio CRP/MCP-1 with WOMAC pain (0.76; 0.37, 1.14; P = 0.023), function (2.43; 1.20, 3.67; P = 0.020) and total (3.29; 1.58, 5.00; P = 0.027). No associations were found for biomarkers or ratios in Low BMI OA. CONCLUSION: In this study, the ratio adipsin/MCP-1 was found to be associated with the knee structural changes and that of CRP/MCP-1 with symptoms in obese OA subjects. Our data further underline the relevance of ratios as biomarkers to a stronger association to OA progression and symptoms.
Assuntos
Proteína C-Reativa/análise , Cartilagem Articular/diagnóstico por imagem , Quimiocina CCL2/sangue , Fator D do Complemento/análise , Progressão da Doença , Osteoartrite do Joelho/diagnóstico por imagem , Biomarcadores/sangue , Índice de Massa Corporal , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Obesidade/epidemiologia , Osteoartrite do Joelho/epidemiologia , Medição da DorRESUMO
BACKGROUND AND PURPOSE: Parkinson's disease (PD) is usually diagnosed clinically from classical motor symptoms, while definitive diagnosis is made postmortem, based on the presence of Lewy bodies and nigral neuron cell loss. α-Synuclein (ASYN), the main protein component of Lewy bodies, clearly plays a role in the neurodegeneration that characterizes PD. Additionally, mutation in the SNCA gene or copy number variations are associated with some forms of familial PD. Here, the objective of the study was to evaluate whether olesoxime, a promising neuroprotective drug can prevent ASYN-mediated neurotoxicity. EXPERIMENTAL APPROACH: We used here a novel, mechanistically approachable and attractive cellular model based on the inducible overexpression of human wild-type ASYN in neuronally differentiated human neuroblastoma (SHSY-5Y) cells. This model demonstrates gradual cellular degeneration, coinciding temporally with the appearance of soluble and membrane-bound ASYN oligomers and cell death combining both apoptotic and non-apoptotic pathways. KEY RESULTS: Olesoxime fully protected differentiated SHSY-5Y cells from cell death, neurite retraction and cytoplasmic shrinkage induced by moderate ASYN overexpression. This protection was associated with a reduction in cytochrome c release from mitochondria and caspase-9 activation suggesting that olesoxime prevented ASYN toxicity by preserving mitochondrial integrity and function. In addition, olesoxime displayed neurotrophic effects on neuronally differentiated SHSY-5Y cells, independent of ASYN expression, by promoting their differentiation. CONCLUSIONS AND IMPLICATIONS: Because ASYN is a common underlying factor in many cases of PD, olesoxime could be a promising therapy to slow neurodegeneration in PD.
Assuntos
Colestenonas/farmacologia , Neurônios/efeitos dos fármacos , Fármacos Neuroprotetores/farmacologia , alfa-Sinucleína/metabolismo , Caspases/metabolismo , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Citocromos c/metabolismo , Humanos , Neurônios/citologia , Neurônios/metabolismoRESUMO
PURPOSE: Few studies compare the variabilities that characterize environmental (EM) and biological monitoring (BM) data. Indeed, comparing their respective variabilities can help to identify the best strategy for evaluating occupational exposure. The objective of this study is to quantify the biological variability associated with 18 bio-indicators currently used in work environments. METHOD: Intra-individual (BV(intra)), inter-individual (BV(inter)), and total biological variability (BV(total)) were quantified using validated physiologically based toxicokinetic (PBTK) models coupled with Monte Carlo simulations. Two environmental exposure profiles with different levels of variability were considered (GSD of 1.5 and 2.0). RESULTS: PBTK models coupled with Monte Carlo simulations were successfully used to predict the biological variability of biological exposure indicators. The predicted values follow a lognormal distribution, characterized by GSD ranging from 1.1 to 2.3. Our results show that there is a link between biological variability and the half-life of bio-indicators, since BV(intra) and BV(total) both decrease as the biological indicator half-lives increase. BV(intra) is always lower than the variability in the air concentrations. On an individual basis, this means that the variability associated with the measurement of biological indicators is always lower than the variability characterizing airborne levels of contaminants. For a group of workers, BM is less variable than EM for bio-indicators with half-lives longer than 10-15 h. CONCLUSION: The variability data obtained in the present study can be useful in the development of BM strategies for exposure assessment and can be used to calculate the number of samples required for guiding industrial hygienists or medical doctors in decision-making.
Assuntos
Poluentes Ocupacionais do Ar/farmacocinética , Monitoramento Ambiental , Modelos Biológicos , Exposição Ocupacional/análise , Acetona/farmacocinética , Meia-Vida , Hexanos/farmacocinética , Humanos , Hidrocarbonetos Aromáticos/farmacocinética , Hidrocarbonetos Clorados/farmacocinética , Método de Monte Carlo , Estatísticas não ParamétricasRESUMO
Biological monitoring of occupational exposure is characterized by important variability, due both to variability in the environment and to biological differences between workers. A quantitative description and understanding of this variability is important for a dependable application of biological monitoring. This work describes this variability, using a toxicokinetic model, for a large range of chemicals for which reference biological reference values exist. A toxicokinetic compartmental model describing both the parent compound and its metabolites was used. For each chemical, compartments were given physiological meaning. Models were elaborated based on physiological, physicochemical, and biochemical data when available, and on half-lives and central compartment concentrations when not available. Fourteen chemicals were studied (arsenic, cadmium, carbon monoxide, chromium, cobalt, ethylbenzene, ethyleneglycol monomethylether, fluorides, lead, mercury, methyl isobutyl ketone, penthachlorophenol, phenol, and toluene), representing 20 biological indicators. Occupational exposures were simulated using Monte Carlo techniques with realistic distributions of both individual physiological parameters and exposure conditions. Resulting biological indicator levels were then analyzed to identify the contribution of environmental and biological variability to total variability. Comparison of predicted biological indicator levels with biological exposure limits showed a high correlation with the model for 19 out of 20 indicators. Variability associated with changes in exposure levels (GSD of 1.5 and 2.0) is shown to be mainly influenced by the kinetics of the biological indicator. Thus, with regard to variability, we can conclude that, for the 14 chemicals modeled, biological monitoring would be preferable to air monitoring. For short half-lives (less than 7 hr), this is very similar to the environmental variability. However, for longer half-lives, estimated variability decreased.
Assuntos
Monitoramento Ambiental , Poluentes Ambientais/análise , Poluentes Ambientais/farmacocinética , Modelos Biológicos , Exposição Ocupacional/análise , Bioensaio , Cinética , Método de Monte CarloRESUMO
This study was undertaken to characterize the toxicokinetics of p-tert-octylphenol (OP), a weak estrogenic compound, in male and female rats. Male and female Sprague-Dawley rats were given a single dose of OP either by oral gavage (50, 125 or 250 mg/kg), by intravenous (iv) injection (2, 4, or 8 mg/kg), or by subcutaneous (sc) injection (125 mg/kg). In a repeated dosing experiment, rats were given OP (oral) daily (25, 50, or 125 mg/kg) for 35 d (female) or 60 d (male). Blood and tissue samples were collected and analyzed for OP content using gas chromatography with detection by mass spectrometry. Blood OP concentrations were generally higher in female than male rats following a single oral or sc administration but were similar following a single iv injection. Tissue OP concentrations were also higher in female than male rats following oral exposure, consistent with the faster metabolism of OP observed in male rat liver microsomes. After subchronic administration, blood OP concentrations were higher at the end of exposure for female (33 d) (2.26-fold, not significant) and male (57 d) (3.47-fold) rats than single dosing but there was no change in the tissue OP concentrations. Gender differences in tissue OP concentrations may contribute, in part, to gender differences in the toxicity of OP in rats. The fact that OP was found in all reproductive tissues confirms its potential for direct endocrine-like effects.
Assuntos
Fenóis/farmacocinética , Fenóis/toxicidade , Tensoativos/farmacocinética , Tensoativos/toxicidade , Administração Oral , Animais , Área Sob a Curva , Feminino , Meia-Vida , Injeções Intravenosas , Injeções Subcutâneas , Masculino , Microssomos/efeitos dos fármacos , Microssomos/metabolismo , Microssomos Hepáticos/efeitos dos fármacos , Microssomos Hepáticos/metabolismo , Ratos , Ratos Sprague-Dawley , Caracteres SexuaisRESUMO
OBJECTIVE: Bone morphogenic protein (BMP) activities are controlled in part by antagonists. In human osteoarthritic (OA) cartilage, the BMP antagonists follistatin and gremlin are increased but differentially regulated. Using the OA dog model, we determined if these BMP antagonists were produced at different stages during the disease process by comparing their in situ temporal and spatial distribution. METHODS: Dogs were sacrificed at 4, 8, 10 and 12 weeks after surgery; normal dogs served as control. Cartilage was removed, differentiating fibrillated and non-fibrillated areas. Immunohistochemistry and morphometric analyses were performed for follistatin, gremlin, BMP-2/4 and IL-1beta. Growth factor-induced gremlin expression was assessed in dog chondrocytes. RESULTS: Follistatin and gremlin production were very low in normal cartilage. Gremlin was significantly up-regulated in both non-fibrillated and fibrillated areas at 4 weeks, and only slightly increased with disease progression. Follistatin showed a time-dependent increased level in the non-fibrillated areas with significance reached at 8-12 weeks; in the fibrillated areas significant high levels were seen as early as 4 weeks. In the whole cartilage, follistatin and IL-1beta temporal production showed similar patterns; this was also true for gremlin and BMP-2/4, though BMP-2/4 production was already high in the normal dogs. Interestingly, data revealed that basic fibroblast growth factor (bFGF) could be another factor increasing gremlin expression early in the disease process. Comparison between superficial and deep zones revealed similar patterns for follistatin and IL-1beta in the superficial zone only; gremlin and BMP-2/4 had similar patterns in both zones. CONCLUSION: Data show, for the first time, different spatial and temporal production of gremlin and follistatin in cartilage during OA progression. These findings may reflect different roles for each antagonist in this disease.
Assuntos
Artrite Experimental/metabolismo , Proteínas Morfogenéticas Ósseas/antagonistas & inibidores , Cartilagem Articular/metabolismo , Folistatina/biossíntese , Animais , Artrite Experimental/patologia , Proteínas Morfogenéticas Ósseas/biossíntese , Cartilagem Articular/patologia , Células Cultivadas , Condrócitos/metabolismo , Progressão da Doença , Cães , Interleucina-1beta/biossíntese , Regulação para CimaRESUMO
BACKGROUND: Human osteoarthritic (OA) chondrocytes were previously classified into L (low)- and H (high)-OA according to matrix metalloproteinase-13 (MMP-13) basal levels and interleukin 1beta (IL1beta) inducibility. In H-OA chondrocytes, the regulatory proteins p130(cas) and nuclear matrix protein 4 (NMP4) acting on the MMP-13 promoter were identified. OBJECTIVE: To identify regulators of MMP-13 expression/production in human L-OA chondrocytes, to determine their effect on the expression of other MMPs and the effect of IL1beta on these molecules. METHODS: The identification of the L-OA chondrocyte proteins interacting specifically with the AGRE site of the MMP-13 promoter was performed by mass spectrometry. Heat shock protein 90beta (Hsp90beta), p130(cas) and NMP4 small interfering RNAs (siRNAs) were transfected into L-OA chondrocytes and incubated with or without IL1beta. Gene expression was determined by real-time PCR, MMP-1 and MMP-13 production by ELISA, and signalling pathway activation by western blotting and ELISA. RESULTS: Hsp90beta was identified as a protein of the L-OA/AGRE-specific complex. Silencing p130(cas) and Hsp90beta significantly increased MMP-13 expression (about four- and twofold, respectively) and production. sip130(cas) affected to a lesser extent MMP-1 expression (twofold) and production. siNMP4 showed no effect. Expression of MMP-2, -3, -9 and -14 was unaffected. Silencing both Hsp90beta and p130(cas) had a significant additive effect on MMP-13, but not on MMP-1 expression, the level of which was similar to that with sip130(cas) alone. IL1beta decreased p130(cas) and Hsp90beta expression/production, indicating another pathway by which this cytokine upregulates MMP expression. The IL1beta-triggered signalling pathways responsible for MMP upregulation were unaffected in the silenced cells. CONCLUSION: This study illustrates the complex regulation of MMP-13 by showing the inhibitory effect of the two cytoplasmic molecules, p130(cas) and Hsp90beta, in L-OA chondrocytes.
Assuntos
Cartilagem Articular/metabolismo , Condrócitos/metabolismo , Proteína Substrato Associada a Crk/metabolismo , Proteínas de Choque Térmico HSP90/metabolismo , Metaloproteinase 13 da Matriz/metabolismo , Osteoartrite do Joelho/metabolismo , Idoso , Sequência de Bases , Células Cultivadas , Proteína Substrato Associada a Crk/análise , Proteína Substrato Associada a Crk/genética , Primers do DNA/genética , Ensaio de Imunoadsorção Enzimática/métodos , Regulação da Expressão Gênica , Proteínas de Choque Térmico HSP90/análise , Proteínas de Choque Térmico HSP90/genética , Humanos , Interleucina-1beta/farmacologia , Metaloproteinase 1 da Matriz/genética , Metaloproteinase 1 da Matriz/metabolismo , Metaloproteinase 13 da Matriz/análise , Metaloproteinase 13 da Matriz/genética , Pessoa de Meia-Idade , Dados de Sequência Molecular , Osteoartrite do Joelho/genética , Interferência de RNA , RNA Interferente Pequeno/farmacologia , Reação em Cadeia da Polimerase Via Transcriptase Reversa/métodos , Estatísticas não Paramétricas , Transativadores/genética , Transativadores/metabolismo , Transfecção/métodosRESUMO
A sensitive and reproducible procedure using gas chromatography coupled with mass spectrometry is described for the determination of p-tert-octylphenol (OP), a persistent degradation product of alkylphenol ethoxylates that binds to the estrogen receptor in blood and tissues. The first step involved the extraction of blood (200 microL) or tissue homogenate (400 microL) with methyl tert-butyl ether, including p-tert-butylphenol (BP) as internal standard. After extraction, the sample was evaporated to dryness with a gentle stream of nitrogen at 45 degrees C, and OP and BP were derivatized with an acetylation reaction involving acetic anhydride and catalyzed by pyridine. Samples were then analyzed by a gas chromatograph equipped with a mass spectrometer (single ion monitoring) with a Varian VF-5ms capillary column. The limit of detection and the limit of quantification of the method in blood were 4.6 and 15.5 ng/mL, respectively. The linearity and reproducibility of the method were acceptable, with coefficients of variation of approximately 10% for blood and ranging between 9% and 27% for tissues. This method was applied to the determination of unchanged OP in blood and tissues obtained from Sprague-Dawley rats after oral and IV OP administration.
Assuntos
Poluentes Ambientais/farmacocinética , Fenóis/farmacocinética , Animais , Poluentes Ambientais/sangue , Feminino , Cromatografia Gasosa-Espectrometria de Massas , Masculino , Fenóis/sangue , Ratos , Ratos Sprague-Dawley , Reprodutibilidade dos Testes , Distribuição TecidualRESUMO
OBJECTIVE: One of the proteoglycan families is the small leucine-rich proteoglycans (SLRPs) that are characterized by their association with collagen fibrils and/or some glycosaminoglycans. Opticin is a glycoprotein and class III member of the SLRP family, which was initially identified in the vitreous humour of the eye. In this study, we first investigated whether opticin is expressed and produced in normal and OA human articular tissues/cells. Further, we investigated the ability of the key metalloprotease involved in cartilage pathology, MMP-13, to cleave human cartilage opticin. METHODS: Opticin gene expression was investigated in normal and OA human chondrocytes, synovial fibroblasts, and subchondral bone osteoblasts by reverse transcriptase-polymerase chain reaction (RT-PCR). Opticin protein production was determined in normal and OA synovial membrane and cartilage by immunohistochemistry. Opticin was isolated from human cartilage using guanidinium chloride extraction, and human MMP-13-induced opticin degradation analyzed by Western blotting. Finally, the opticin MMP-13 cleavage site was determined. RESULTS: Opticin was expressed in human chondrocytes, synovial fibroblasts and subchondral osteoblasts, and the protein identified in synovial membrane and cartilage. At the protein level, OA cartilage showed a slightly higher level of opticin positive stained chondrocytes than normal cartilage; this did not reach statistical significance. However, in contrast with OA, normal cartilage demonstrated a high level of matrix staining in the superficial zone of the tissue, suggesting that in the OA cartilage matrix, opticin is degraded. Data also showed that cartilage opticin could be cleaved by MMP-13 after only 2h of incubation, indicating a preferential substrate compared to other SLRPs for this enzyme. Microsequencing revealed a major cleavage site at the G(104)/L(105)LAAP and a minor at P(109)/A(110)NHPG upon MMP-13 exposure. CONCLUSION: We demonstrated, for the first time, that opticin is expressed and produced in human articular tissues. Our data also showed that opticin in OA cartilage is degraded in a process that could be mediated by MMP-13. As opticin may contribute towards the structural stability of cartilage, its cleavage by MMP-13 may predispose cartilage to degeneration, particularly at the surface.
Assuntos
Proteínas da Matriz Extracelular/biossíntese , Articulação do Joelho/metabolismo , Metaloproteinase 13 da Matriz/farmacologia , Osteoartrite do Joelho/metabolismo , Proteoglicanas/biossíntese , Idoso , Idoso de 80 Anos ou mais , Artroplastia do Joelho , Cartilagem Articular/efeitos dos fármacos , Cartilagem Articular/metabolismo , Condrócitos/metabolismo , Proteínas da Matriz Extracelular/efeitos dos fármacos , Proteínas da Matriz Extracelular/genética , Expressão Gênica , Humanos , Pessoa de Meia-Idade , Reação em Cadeia da Polimerase/métodos , Proteoglicanas/efeitos dos fármacos , Proteoglicanas/genética , RNA Mensageiro/genética , Membrana Sinovial/metabolismoRESUMO
A physiologically based pharmacokinetic (PBPK) model was developed for inhaled ethylbenzene (EB) in B6C3F1 mice. The mouse physiological parameters were obtained from the literature, but the blood:air and tissue:air partition coefficients were determined by vial equilibration technique. The maximal velocity for hepatic metabolism (Vmax) obtained from a previously published rat study was increased by a factor of approximately 3 to account for enzyme induction during repeated exposures. The Michaelis affinity constant (Km) for hepatic metabolism of EB, obtained from a previously published rat PBPK modeling study, was kept unchanged during single and repeated exposure scenarios. Hepatic metabolism alone could not adequately describe the clearance of EB from mouse blood. Additional metabolism was assumed to be localized in the lung. The parameters for pulmonary metabolism were obtained by optimization of PBPK model fits to kinetic data collected following exposures to 75-1000 ppm. The PBPK model successfully predicted all available blood and tissue concentration data in mice exposed to 75 or 750 ppm EB. Overall, the results indicate that the rate of EB clearance is markedly higher in B6C3F1 mice than rats or humans and exceeds the hepatic metabolism capacity. Available biochemical evidence is consistent with a significant role for pulmonary metabolism; however, the extent to which the extrahepatic metabolism is localized in the lung is unclear. Overall, the PBPK model developed for the mouse adequately simulated the blood and tissue kinetics of EB by accounting for its high rate of clearance.
Assuntos
Derivados de Benzeno/farmacocinética , Fígado/metabolismo , Pulmão/metabolismo , Modelos Biológicos , Administração por Inalação , Animais , Derivados de Benzeno/administração & dosagem , Derivados de Benzeno/sangue , Débito Cardíaco , Feminino , Masculino , Taxa de Depuração Metabólica , CamundongosRESUMO
BACKGROUND: Carpal tunnel syndrome is a clinical syndrome manifested by signs and symptoms of irritation of the median nerve at the carpal tunnel in the wrist. Local corticosteroid injection for carpal tunnel syndrome has been studied but its effectiveness is unknown. OBJECTIVES: To evaluate the effectiveness of local corticosteroid injection for carpal tunnel syndrome versus placebo injection or other non-surgical interventions. SEARCH STRATEGY: We searched the Cochrane Neuromuscular Disease Group Trials register (searched May 2006), MEDLINE (searched January 1966 to May 2006), EMBASE (searched January 1980 to May 2006) and CINAHL (searched January 1982 to May 2006). SELECTION CRITERIA: Randomized or quasi-randomized studies. DATA COLLECTION AND ANALYSIS: Three authors independently selected the trials and rated their overall quality. Relative risks and 95% confidence intervals were calculated for each trial and summary relative risks and 95% confidence intervals were also calculated. MAIN RESULTS: We included 12 studies with altogether 671 participants. Two high quality randomized controlled trials with altogether 141 participants demonstrated clinical improvement of carpal tunnel syndrome at one month or less following local corticosteroid compared to placebo injection (relative risk 2.58 (95% confidence intervals 1.72 to 3.87)). One trial compared local corticosteroid injection to oral corticosteroid and at 12 weeks after treatment there was significantly more improvement in the injection group (mean difference -7.10 (95% confidence intervals -11.68 to -2.52)). In one trial, the rate of improvement after one month was greater after local than systemic corticosteroid injection (relative risk 3.17 (95% confidence intervals 1.02 to 9.87)). In one trial, symptoms did not improve significantly more in the injection group at eight weeks after injection compared to treatment with anti-inflammatory medication and splinting (mean difference 0.10 (95% confidence intervals -0.33 to 0.53)). Two injections versus one injection of local corticosteroid did not provide further clinical improvement, mean difference -3.80 (95% CI -9.27 to 1.67). AUTHORS' CONCLUSIONS: Local corticosteroid injection for carpal tunnel syndrome provides greater clinical improvement in symptoms one month after injection compared to placebo. Significant symptom relief beyond one month has not been demonstrated. Local corticosteroid injection provides significantly greater clinical improvement than oral corticosteroid for up to three months. Local corticosteroid injection does not significantly improve clinical outcome compared to either anti-inflammatory treatment and splinting after eight weeks or Helium-Neon laser treatment after six months. Two local corticosteroid injections do not provide significant added clinical benefit compared to one injection.
Assuntos
Anti-Inflamatórios/administração & dosagem , Síndrome do Túnel Carpal/tratamento farmacológico , Humanos , Injeções Intra-Articulares , Iontoforese , Fonoforese , Ensaios Clínicos Controlados Aleatórios como Assunto , Esteroides/administração & dosagemRESUMO
OBJECTIVE: To investigate the distribution of the bone morphogenic protein (BMP) antagonist chordin in normal and osteoarthritic cartilage and synovial membranes, and its regulation in chondrocytes and synovial fibroblasts by inflammatory and growth factors. METHODS: Localisation of chordin in tissues was undertaken by immunohistochemistry and gene regulation was determined by real time polymerase chain reaction. RESULTS: In normal cartilage, chordin was found at low levels (mean (SD), 7.6 (1.3)%), mainly in the very superficial layers. In osteoarthritis, chordin was also found in the superficial layers (8.9 (1.1)%), though at a significantly higher level (24.7 (1.5)%) in the last two thirds of the cartilage. In contrast to normal cells, chordin mRNA and protein levels were significantly downregulated (p<0.01) in osteoarthritic chondrocytes by all the growth factors tested. Interferon gamma stimulated chordin expression in normal but not in osteoarthritic chondrocytes (p<0.0002), while interleukin 1 beta and tumour necrosis factor alpha did not affect the expression level. However, no difference was found in either the distribution or regulation of chordin in normal and osteoarthritic synovial membranes or synovial fibroblasts. CONCLUSIONS: The differential distribution and regulation of chordin in normal and osteoarthritic cartilage and chondrocytes suggests an involvement of this antagonist in the osteoarthritic process.
Assuntos
Proteínas Morfogenéticas Ósseas/antagonistas & inibidores , Condrócitos/metabolismo , Glicoproteínas/metabolismo , Peptídeos e Proteínas de Sinalização Intercelular/metabolismo , Osteoartrite do Joelho/metabolismo , Membrana Sinovial/metabolismo , Idoso , Becaplermina , Proteínas Morfogenéticas Ósseas/metabolismo , Estudos de Casos e Controles , Células Cultivadas , Condrócitos/química , Fator 2 de Crescimento de Fibroblastos/farmacologia , Fibroblastos/efeitos dos fármacos , Fibroblastos/metabolismo , Glicoproteínas/análise , Humanos , Imuno-Histoquímica/métodos , Peptídeos e Proteínas de Sinalização Intercelular/análise , Interferon gama/farmacologia , Interleucina-1/farmacologia , Pessoa de Meia-Idade , Fator de Crescimento Derivado de Plaquetas/farmacologia , Proteínas Proto-Oncogênicas c-sis , Membrana Sinovial/química , Fator de Necrose Tumoral alfa/farmacologiaRESUMO
The objective of the present study was to characterize the inhalation pharmacokinetics of ethylbenzene (EB) in male and female B6C3F1 mice following single and repeated exposures. Initially, groups of 28 male and female mice were exposed for 4 h to 75, 200, 500, or 1000 ppm in order to determine potential non-linearity in the kinetics of EB. Then, groups of male and female mice were exposed for 6 h to 75 ppm and 750 ppm (corresponding to the NTP exposures) for 1 or 7 consecutive days, to evaluate whether EB kinetics was altered during repeated exposures, The maximal blood concentration (Cmax; mean+/-SD, n=4) observed in female mice at the end of a 4-h exposure to 75, 200, 500, and 1000 ppm was 0.53+/-0.18, 2.26+/-0.38, 19.17+/-2.74, and 82.36+/-16.66 mg/L, respectively. The areas under the concentration vs. time curve (AUCs) following 4-h exposure to 75, 200, 500, and 1000 ppm were 88.5, 414.0, 3612.2, and 19,104.1 mg/L/min, respectively, in female mice, and 116.7, 425.7, 3148.3, and 16,039.1 mg/L/min in male mice. The comparison of Cmax and the kinetic profile of EB in mice exposed to 75 ppm suggests that they are similar between 1-day and 7-day exposures. However, at 750 ppm, the rate of EB elimination would appear to be greater after repeated exposures than single exposure, the pattern being evident in both male and female mice. Overall, the single and repeated exposure pharmacokinetic data collected in the present study suggest that EB kinetics is saturable at exposure concentrations exceeding 500 ppm (and therefore at 750 ppm used in the NTP mouse cancer bioassay) but is in the linear range at the lower concentration used in the bioassay (75 ppm). These data suggest that consideration of the nature and magnitude of non-linear kinetics and induction of metabolism during repeated exposures is essential for the conduct of a scientifically sound analysis of EB cancer dose-response data collected in B6C3F1 mice.
Assuntos
Poluentes Atmosféricos/farmacocinética , Derivados de Benzeno/farmacocinética , Poluentes Atmosféricos/sangue , Animais , Área Sob a Curva , Derivados de Benzeno/sangue , Relação Dose-Resposta a Droga , Feminino , Exposição por Inalação , Masculino , Camundongos , Camundongos Endogâmicos , Dinâmica não LinearRESUMO
We used a modified physiologically based pharmacokinetic (PBPK) to describe/predict n-hexane (HEX) alveolar air concentrations and free 2,5-HD urinary concentrations in humans exposed to n-HEX by inhalation during a typical workweek. The effect of an increase in workload intensity on these two exposure indicators was assessed and, using Monte Carlo simulation, the impact of biological variability was investigated. The model predicted HEX alveolar air concentrations at rest of 19.0 ppm (25 ppm exposure) and 38.7 ppm (50 ppm exposure) at the end of the last working day (day 5), while free 2,5-HD urinary concentrations of 3.4 micromol/L (25 ppm) and 6.3 micromol/L (50 ppm) were predicted for the same period (last 4.5 hours of Day 5). Monte Carlo simulations showed that the range of values expected to occur in a group of 1000 individuals exposed to 50 ppm of HEX (95% confidence interval) for free 2,5-HD (1.7-14.7 micromol/L) is much higher compared with alveolar air HEX (33.4-46 ppm). Simulations of exposure at 50 ppm with different workloads predicted that an increase in workload intensity would not greatly affect both indicators studied. However, the alveolar air HEX concentration is more sensitive to modifications of workload intensity and time of sampling, after the end of exposure, compared with 2,5-HD. The PBPK model successfully described the HEX alveolar air concentrations and free 2,5-HD urinary concentrations measured in human volunteers and is the first, to our knowledge, to describe the excretion kinetics of free 2,5-HD in humans over a 5-day period.
Assuntos
Exercício Físico , Hexanos/farmacocinética , Hexanonas/urina , Exposição por Inalação , Modelos Biológicos , Neurotoxinas/urina , Exposição Ocupacional , Previsões , Humanos , Cinética , Alvéolos Pulmonares/química , Respiração , Carga de TrabalhoRESUMO
BACKGROUND: MMP-13 is one of the most important metalloproteases (MMP) involved in osteoarthritis. Licofelone, a novel dual inhibitor of cyclo-oxygenases (COX) and 5-lipoxygenase (5-LOX), can modulate MMP-13 production in human osteoarthritis chondrocytes. OBJECTIVE: To evaluate the impact of licofelone on MMP-13 expression/production, promoter, and major MAP kinase signalling pathways and transcription factors. METHODS: Human osteoarthritis chondrocytes were stimulated by interleukin 1beta (IL1beta) and treated with or without: licofelone (0.3, 1, or 3 mug/ml); NS-398 (10 muM; a specific COX-2 inhibitor); or BayX-1005 (10 muM; a specific 5-LOX inhibitor). MMP-13 synthesis was determined by specific enzyme linked immunosorbent assay, and expression by real time polymerase chain reaction. The effect of licofelone on the MMP-13 promoter was studied through transient transfection; dexamethasone (10(-7) M) was used as comparison. The effect on IL1beta induced MMP-13 signalling pathways was determined using specific ELISA for phosphorylated MAP kinases and transcription factors. RESULTS: Licofelone dose dependently inhibited the IL1beta stimulated production and expression of MMP-13. NS-398 and BayX-1005 had very little effect. Licofelone also inhibited MMP-13 transcription on each of the promoter constructs used. The licofelone inhibition was comparable to that obtained with dexamethasone. Licofelone had no effect on phosphorylated p44/42 or JNK1/2; however, it decreased phosphorylated c-jun and inhibited phosphorylated p38, CREB, and AP-1 activity. CONCLUSIONS: Licofelone inhibited MMP-13 production under proinflammatory conditions on human osteoarthritis chondrocytes, through inhibition of the p38/AP-1 pathway and the transcription factor CREB. This may explain some of the mechanisms whereby licofelone exerts its positive effect on osteoarthritic changes.
Assuntos
Acetatos/farmacologia , Condrócitos/efeitos dos fármacos , Colagenases/efeitos dos fármacos , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Osteoartrite do Joelho/enzimologia , Pirróis/farmacologia , Idoso , Células Cultivadas , Colagenases/biossíntese , Colagenases/genética , Inibidores de Ciclo-Oxigenase/farmacologia , Relação Dose-Resposta a Droga , Humanos , Interleucina-1/farmacologia , Inibidores de Lipoxigenase , Metaloproteinase 13 da Matriz , Pessoa de Meia-Idade , Osteoartrite do Joelho/patologia , Regiões Promotoras Genéticas/efeitos dos fármacos , Transdução de Sinais/efeitos dos fármacos , Acetato de Tetradecanoilforbol/farmacologia , Transcrição Gênica/efeitos dos fármacosRESUMO
OBJECTIVE: Collagenase-3 is a metalloprotease that plays a role in tissue remodeling and pathological processes including arthritis. The human gene is transcribed into major (3.0 and 2.5 kb) and minor (2.2/2.0 kb) transcripts, as seen in Northern blot assays. We investigated the possibility that other transcripts, not detectable by Northern blot, were synthesized as either coding or regulatory RNAs that would modulate collagenase-3 expression and function/activity. DESIGN: We screened a cDNA library and total RNA from human chondrocytes by plaque hybridization and RT-PCR, and expressed the transcripts in a cellular environment. The levels of expression of each transcript in normal and osteoarthritic joint cells and cartilage were monitored by RT-PCR. RESULTS: We identified five different collagenase-3 RNA species derived from alternative polyadenylation sites (COL3-APS), internal deletion (COL3-DEL), alternative splicing (COL3-9B/COL3-9B-2), and different transcription initiation site (COL3-ATS and COL3-ATS-INT). Each transcript could be translated in a cellular environment. Interestingly, the proteins translated from the COL3-DEL and COL3-9B-2 transcripts had a modified hemopexin-like domain, suggesting altered collagenolytic activities. The transcript types COL3-APS, COL3-9B-2, and COL3-ATS were up-regulated in the osteoarthritic samples and expressed in the chondrosarcoma cell line SW1353. CONCLUSION: Our data show that the human collagenase-3 gene is subjected to different levels of regulation and constitutes a more complex system than was originally thought.
Assuntos
Cartilagem Articular/enzimologia , Colagenases/genética , Osteoartrite do Joelho/enzimologia , RNA Mensageiro/genética , Processamento Alternativo/fisiologia , Sequência de Aminoácidos , Células Cultivadas , Condrócitos/enzimologia , Colagenases/metabolismo , DNA Complementar/genética , Ensaio de Imunoadsorção Enzimática/métodos , Humanos , Hibridização In Situ/métodos , Articulação do Joelho/enzimologia , Metaloproteinase 13 da Matriz , Pessoa de Meia-Idade , Dados de Sequência Molecular , Poliadenilação/fisiologia , RNA Mensageiro/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa/métodos , Homologia de Sequência , Membrana Sinovial/enzimologia , Sítio de Iniciação de Transcrição/fisiologia , Transcrição GênicaRESUMO
BACKGROUND: Carpal tunnel syndrome is a clinical syndrome manifested by signs and symptoms of irritation of the median nerve at the level of the carpal tunnel in the wrist. Local corticosteroid injection for carpal tunnel syndrome has been studied but its effectiveness and duration of benefit of local corticosteroid injection for Carpal tunnel syndrome remain unknown. OBJECTIVES: To evaluate the effectiveness of local steroid injection for carpal tunnel syndrome versus placebo injection or other non-surgical interventions in improving clinical outcome and to determine the length of symptom relief. SEARCH STRATEGY: We searched the Cochrane Neuromuscular Disease Group register (searched June 2002), MEDLINE (searched January 1966 to May 2002), EMBASE (searched January 1980 to May 2002)and CINAHL(searched January 1982 to May 2002). SELECTION CRITERIA: We included randomized or quasi-randomized studies of participants with carpal tunnel syndrome treated with local corticosteroid injection. The primary outcome measure was clinical improvement. DATA COLLECTION AND ANALYSIS: Three reviewers independently selected the trials to be included rated for their overall quality. Relative risks and 95% confidence intervals were calculated for each trial and summary relative risks and 95% confidence intervals were also calculated. MAIN RESULTS: We identified nine randomized controlled trials. Four were excluded. One trial demonstrated clinical improvement of carpal tunnel syndrome at one month following local corticosteroid compared to placebo injection (Relative risk 3.83 (95% confidence intervals 1.82 to 8.05)). One trial compared local corticosteroid injection to oral steroid and at three months after treatment there was a significant improvement in the injection group (mean difference -7.00 (95% confidence intervals -11.58 to -2.42)). In one trial the rate of improvement after one month was greater after local than systemic corticosteroid injection (Relative risk 3.17(95% confidence intervals 1.02 to 9.87)). In one trial symptoms did not improve significantly for the injection group at eight weeks after injection compared to treatment with anti-inflammatory medication and splinting (mean difference 0.10 (95% confidence intervals -0.33 to 0.53)). Although local steroid injection did provide benefit compared to Helium-Neon Laser treatment at two weeks after onset of treatment (Relative risk 0.27 (95% CI 0.09 to 0.83), this effect did not hold at six months follow-up (Relative risk 0.76 (95% confidence intervals 0.48 to 1.21). REVIEWER'S CONCLUSIONS: Local corticosteroid injection for carpal tunnel syndrome provides greater clinical improvement in symptoms one month after injection compared to placebo. Symptom relief beyond one month compared to placebo has not been demonstrated. Local corticosteroid injection provides significantly greater clinical improvement compared to oral steroid up to three months after treatment. Local corticosteroid injection does not provide improved clinical outcome compared to either anti-inflammatory treatment and splinting after eight weeks or Helium -Neon laser treatment after six months.
Assuntos
Anti-Inflamatórios/administração & dosagem , Síndrome do Túnel Carpal/tratamento farmacológico , Humanos , Injeções Intra-Articulares , Ensaios Clínicos Controlados Aleatórios como Assunto , EsteroidesRESUMO
BACKGROUND: Access to primary healthcare among people with physical disabilities has been a neglected research area in Canada. The authors sought to examine the extent of access to and satisfaction with primary healthcare services for people with physical disabilities living in Canada's largest metropolitan area -- the Toronto region. METHODS: An anonymous self-report questionnaire regarding access to and perceived quality of primary healthcare was mailed to a convenience sample of 1026 members of several disability organizations as well as persons discharged from a rehabilitation hospital within the past 2 years. For the 201 returned surveys (response rate = 20%), the authors evaluated the perceived extent of access to primary healthcare services as well as the level of satisfaction with the quality of these services. RESULTS: Among the respondents to the questionnaire, 17.4% reported having difficulty obtaining a family doctor's services and 8.0% reported having been refused medical treatment by a family doctor because of their disability. Respondents also reported difficulty in physically accessing their family doctor's office (32.3%), equipment (38.3%), and washroom (22.9%). Although 82.1% of respondents claimed they were very or somewhat satisfied with their family doctor's services, 19.4% felt they were receiving inadequate primary healthcare and 21.9% felt that their disability prevented them from receiving appropriate primary healthcare. DISCUSSION: Although people who experienced more difficulties may have been more likely to respond to this survey, a significant proportion of people with physical disabilities feel they are experiencing difficulty accessing adequate and appropriate primary healthcare services. Possible solutions to some of the identified access barriers and areas where further research may be required are described.
Assuntos
Pessoas com Deficiência , Acessibilidade aos Serviços de Saúde , Atenção Primária à Saúde , Adolescente , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Ontário , Satisfação do Paciente , Qualidade da Assistência à Saúde , Inquéritos e QuestionáriosRESUMO
BACKGROUND: The ability of persons with disabilities to access quality primary care in Canada is not well documented. This article reports on the perceived quality of primary care received by persons with disabilities by looking at utilization of elements of the health maintenance examination, referrals, health promotion, healthcare provider role clarification, and satisfaction. METHODS: A sample of convenience was undertaken whereby an anonymous self-report questionnaire, which included the Short Form-36 Health Survey, was mailed to members of several Canadian disability organizations and persons discharged within the last 2 years from a rehabilitation hospital. The Statistical Package for the Social Sciences was used to analyze the data. RESULTS: A total of 201 individuals (20% response rate) completed and returned the surveys, 61.2% of whom were women. Some elements of the health maintenance examination, including Pap tests, mammogram referral, and measurement of blood pressure (BP), were not markedly different from population census data. Inquiry around health promotion was low, as 61.7% of our sample did not receive a functional assessment, 58.2% were not asked about emotions, and only 10% were asked about physical or sexual violence. Diet, exercise, smoking, pain, sleep, alcohol, sex, sexually transmitted diseases (STDs), and reproductive choices were discussed in varying degrees. INTERPRETATION: Among respondents in our survey, disabled women were able to access important screening tests. Health promotion services, however, were often not offered. The particular healthcare needs of disabled women and men -- eg, having a condition that may be progressive, being at increased risk of secondary disability and the added effects of aging -- may be addressed more effectively by including health promotion. It is proposed that functional assessment, emotional inquiry, and role clarification could improve the delivery of health promotion and the perceived quality of care received.
Assuntos
Pessoas com Deficiência , Atenção Primária à Saúde , Qualidade da Assistência à Saúde , Adolescente , Adulto , Idoso , Feminino , Acessibilidade aos Serviços de Saúde , Humanos , Masculino , Pessoa de Meia-Idade , Ontário , Satisfação do Paciente , Inquéritos e QuestionáriosRESUMO
The objective of the present study was to determine the rat blood:air partition coefficients (P(b:a)) of chloroform, bromodichloromethane, dibromochloromethane and bromoform present in vitro individually or as mixtures. The experimentally determined P(b:a) of chloroform, bromodichloromethane, dibromochloromethane and bromoform present individually corresponded to (mean +/- SD, n = 8) 21.3 +/- 1.8, 41.8 +/- 6.2, 97.5 +/- 4.1, and 187 +/- 7.4, respectively. The P(b:a) of these trihalomethanes (THMs) showed a decreasing trend during mixed in vitro exposures to 0.138 +/- 0.002 or 0.273 +/- 0.002 micromol of each of the four THMs. In general, the P(b:a) determined during mixed exposures differed by < or = 15% of the average P(b:a) determined for THMs present individually. The results of this study suggest that an alteration of P(b:a) of the individual THMs is unlikely to occur at the blood concentrations of THMs observed during mixed exposures in rats.