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1.
Int Nurs Rev ; 67(2): 294-299, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32367661

RESUMO

AIM: This investigation explored the extent to which nurses' own health is a priority for global National Nursing Associations. BACKGROUND: There is a growing body of evidence linking staff health and well-being and key dimensions of service quality, including patient safety, patient experience and the effectiveness of patient care. INTRODUCTION: The International Council of Nurses is a federation of more than 130 National Nurses Associations, representing more than 20 million nurses worldwide. Representatives from these Associations attended a Congress in Singapore in 2019 at which a survey was conducted. METHODS: A convenience sample of 37 leaders of National Nurse Associations from 33 countries and 61 nurse representatives took part in a survey. RESULTS: The majority of nurse leaders and participants believed that nurses' own health should be a priority to be addressed, principally because a healthy nurse is better able to provide good patient care. All of the examples offered about how these Associations address nurses' own health were about actions to prompt individual health behaviour change. DISCUSSION: The National Nurses Associations did not have a common terminology to talk about nurses' own health. Taking care of one's own health was included as part of the professional role and most nurse leaders thought that working conditions contributed to ill health. CONCLUSIONS: There is widespread agreement that nurses' own health matters but for most National Nurses Associations it is not a current priority. IMPLICATIONS FOR NURSING POLICY: Going forward nurse health and wellbeing should be a core principle for health services and professional associations, and additional research is needed that demonstrates if improving working environments contributes to nurse retention and recruitment.


Assuntos
Nível de Saúde , Cuidados de Enfermagem/estatística & dados numéricos , Recursos Humanos de Enfermagem/estatística & dados numéricos , Sociedades de Enfermagem/estatística & dados numéricos , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Singapura , Inquéritos e Questionários
2.
Br J Surg ; 93(7): 885-90, 2006 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-16673355

RESUMO

BACKGROUND: It has been suggested that too many English boys undergo circumcision. This report describes how circumcision rates have changed in England between 1997 and 2003, including data on complication rates and on how age, medical indication and surgical specialty affect postoperative haemorrhage rates. METHODS: Data were extracted from the Hospital Episode Statistics database of admissions to National Health Service hospitals in England. Patients were included in the study if an Office of Population Censuses and Surveys version 4 code for circumcision was present in any of the operative procedure fields of the database; 75 868 boys below 15 years of age were included in the study. RESULTS: Circumcision rates declined by about 20 per cent, from 2.6 per 1000 boys per year in 1997 to 2.1 in 2003. Between 2000 and 2003, circumcision rates remained static at 2.1 per 1000 boys per year. Circumcision rates fell by 31.2 per cent for boys aged 0-4 years, 9.3 per cent for boys aged 5-9 years and increased by 7.7 per cent in boys aged 10-14 years; 90.2 per cent of circumcisions were done for phimosis and 1.2 per cent of boys experienced a complication. CONCLUSION: Circumcision rates in England continued to fall up until 2000, particularly in those aged under 5 years, in whom pathological phimosis is rare. The circumcision rate remains five times higher than the reported incidence of Phimosis.


Assuntos
Circuncisão Masculina/tendências , Fimose/cirurgia , Adolescente , Criança , Pré-Escolar , Circuncisão Masculina/efeitos adversos , Inglaterra , Humanos , Lactente , Recém-Nascido , Masculino
3.
Int Urol Nephrol ; 38(1): 161-2, 2006.
Artigo em Inglês | MEDLINE | ID: mdl-16502074

RESUMO

A number of disease processes are associated with an elevation in serum PSA. However, several studies have concluded that cycling is not an activity associated with an elevation in PSA. Herein, we summarise the literature and describe the case of a 54-year-old man who had presented to his General Practitioner (GP) with lower urinary tract symptoms 3 days after the completion of a 39-h endurance cycle ride. The PSA level was initially found to be elevated at 28 ng/ml, but decreased to 4 ng/ml and then 2 ng/ml within two and six months of the date of the cycle ride, respectively. It is probable that the elevation in PSA was caused by prolonged mechanical stimulation of the prostate during the cycle ride.


Assuntos
Ciclismo/fisiologia , Antígeno Prostático Específico/sangue , Prostatite/sangue , Prostatite/etiologia , Humanos , Masculino , Pessoa de Meia-Idade , Estimulação Física , Remissão Espontânea
5.
Life Sci ; 75(24): 2879-95, 2004 Oct 29.
Artigo em Inglês | MEDLINE | ID: mdl-15454340

RESUMO

Prolonged use of glucocorticoids is associated with decreased bone formation, increased resorption and osteonecrosis, through direct and indirect effects on the activity and viability of bone effector cells, osteoblasts and osteoclasts, and osteocytes. This study has investigated molecular pathways implicated in Dexamethasone-induced apoptosis of osteocytes, using a cell line and primary chicken cells. MLO-Y4 osteocytes were pre-treated with several bisphosphonates representing a range of anti-resorptive activities and conformation/structure relationships, and were subsequently challenged with Dexamethasone. Apoptotic cells were detected at various times after treatment using morphological and biochemical criteria. Dex was shown to induce apoptosis associated with the Fas/CD95 death receptor and in a caspase 8 dependent manner. The apoptotic response was inhibited by all variants of the BP molecules, including those with reduced anti-resorptive activity, indicating that Dex-induced apoptosis is independent of anti-osteoclastic activity. Dex-induced apoptosis was associated with a transient increase in phosphorylated ERK 1/2 and was blocked by the ERK inhibitor UO126. In addition, both UO126 and BPs decreased localization of Fas to the cell membrane. ERK activation by PMA did not induce death or Fas upregulation, suggesting that Fas may be important for the induction of apoptosis and the existence of an additional factor activated by Dex which enables the cooperation between the Dex-activated ERK and Fas pathways, during apoptosis of osteocytes. Furthermore, upregulation of death and Fas was not accompanied by upregulation of FasL, pointing to the possible existence of FasL-independent Fas-associated death in these cells.


Assuntos
Apoptose/efeitos dos fármacos , Dexametasona/farmacologia , Organofosfonatos/farmacologia , Osteócitos/efeitos dos fármacos , Receptor fas/metabolismo , Análise de Variância , Animais , Western Blotting , Butadienos/farmacologia , Linhagem Celular , Galinhas , Primers do DNA , Imuno-Histoquímica , Imunoprecipitação , Camundongos , Proteína Quinase 3 Ativada por Mitógeno/antagonistas & inibidores , Proteína Quinase 3 Ativada por Mitógeno/metabolismo , Nitrilas/farmacologia , RNA/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Transdução de Sinais/efeitos dos fármacos
6.
Int J Clin Pract ; 57(8): 705-9, 2003 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-14627182

RESUMO

Dutasteride is a new 5-alpha reductase inhibitor for the treatment of men with moderate to severe lower urinary tract symptoms secondary to benign prostatic hyperplasia. It has been available in the UK since March 2003. It is a competitive inhibitor of both type I and type II isoforms of the 5-alpha reductase enzyme that converts testosterone to the more potent androgen, dihydrotestosterone. Randomised controlled studies have shown dutasteride to be statistically more effective than placebo in reducing lower urinary tract symptoms and increasing maximum urinary flow rates. This is a consequence of a reduction in serum dihydrotestosterone and hormone dependent prostate volume. Dutasteride has also been shown to decrease the absolute risk of urinary retention and the need for prostate-related surgery when compared to placebo taken over a 24-month period. In this review article we discuss the pharmacology and clinical effects of dutasteride, a new dual-acting 5-alpha reductase inhibitor.


Assuntos
Inibidores de 5-alfa Redutase , Azasteroides/administração & dosagem , Hiperplasia Prostática/tratamento farmacológico , Retenção Urinária/tratamento farmacológico , Azasteroides/farmacocinética , Azasteroides/farmacologia , Dutasterida , Humanos , Masculino , Resultado do Tratamento
7.
Emerg Med J ; 19(5): 468-9, 2002 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-12205014

RESUMO

Failure to detect a pneumothorax may have serious complications. A case of a pneumothorax, which may have been overlooked if thoracic computed tomography had not been performed, is discussed.


Assuntos
Pneumotórax/diagnóstico por imagem , Adulto , Humanos , Masculino , Tomografia Computadorizada por Raios X
8.
Cells Tissues Organs ; 169(3): 265-71, 2001.
Artigo em Inglês | MEDLINE | ID: mdl-11455122

RESUMO

Recent drug discovery has been driven largely by a genomics-based approach. This revolution in pharmaceutics is based on localized expression of either a novel gene or homologue of a known gene found in cDNA libraries made from normal versus diseased tissue. The choice and quality of cDNA library is critical for the success of this approach. Expression is normally verified at the cellular level by either immunocytochemistry or in situ hybridization. Activity of the recombinant protein in secondary cell-based assays allows highthroughput screens to be formulated to identify small-molecule effectors of this protein. More recently, a proteomics approach has also been incorporated into this process. This technology directly measures proteins whose expression is localized in disease tissue as the basis for cell-based screens to look for either activators or inhibitors, of this activity. The majority of screens are designed to look for inhibitors. Activity of small-molecules found by screening gives rise to pharmacokinetic studies and verification of activity in animal models of the disease. Structure-activity relationship (SAR) optimization of these small-molecules allows for suitable oral bioavailability and pharmacokinetics, resulting in compounds progressing from discovery to development. Based on these strategies, we have developed inhibitors of osteoclast-mediated bone resorption and are currently screening for bone anabolic agents. In addition, we have also developed small-molecule caspase inhibitors which prevent chondrocyte apoptosis and retain cell function in an attempt to find therapeutic agents to either prevent or treat osteoarthritis. These agents may well have utility in the treatment of temporomandibular joint diseases.


Assuntos
Desenho de Fármacos , Animais , Reabsorção Óssea/prevenção & controle , Inibidores de Caspase , Inibidores de Cisteína Proteinase/síntese química , Inibidores de Cisteína Proteinase/farmacologia , Avaliação Pré-Clínica de Medicamentos , Genômica , Humanos , Proteoma , Relação Estrutura-Atividade , Transtornos da Articulação Temporomandibular/tratamento farmacológico
9.
Cancer Chemother Pharmacol ; 47(5): 437-43, 2001 May.
Artigo em Inglês | MEDLINE | ID: mdl-11391860

RESUMO

PURPOSE: There is a need to find novel oestrogen receptor (ER) ligands that antagonize oestrogen action in the reproductive tissues and would therefore have therapeutic potential in oestrogen-dependent tumours. We tested novel ER ligands in both breast and endometrial cells to profile agonism/antagonism in these oestrogen target reproductive tissues. METHODS: Novel analogues of the ER antagonist ICI 182,780 were synthesized and tested for their ability to inhibit gene expression dependent on oestrogen response elements (ERE) in human breast (MCF-7) and endometrial (Ishikawa) cell lines. This activity was correlated with inhibition of oestrogen-induced cell proliferation and ER binding. RESULTS: The sulphide analogue (compound 1) and sulphone analogue (compound 2) had no intrinsic ERE-dependent agonism in either breast cancer or endometrial cells in culture. All three compounds dose-dependently inhibited ERE-mediated oestrogen agonism. Moreover, these ER ligands inhibited oestrogen-stimulated proliferation of breast cancer and endometrial cells. ICI 182,780, compound 1 and compound 2 were all able to bind both isoforms of the ER (ER alpha and ER beta). In endometrial cells, the relative binding to ER beta correlated with the ERE-dependent antioestrogenic effect of these ligands, suggesting that in this tissue this receptor is the predominant isoform that determines antioestrogenic activity. CONCLUSIONS: The ability of these analogues of ICI 182,780 to inhibit oestrogen-stimulated transcriptional activity and cell proliferation suggests that these agents, in particular the sulphone analogue, have therapeutic potential in the treatment of breast cancer without exhibiting the unwanted oestrogenic effects in the endometrium.


Assuntos
Antineoplásicos/farmacologia , Neoplasias da Mama/metabolismo , Endométrio/citologia , Estradiol/análogos & derivados , Estradiol/farmacologia , Antagonistas de Estrogênios/farmacologia , Neoplasias Hormônio-Dependentes/metabolismo , Receptores de Estrogênio/efeitos dos fármacos , Divisão Celular/efeitos dos fármacos , Endométrio/efeitos dos fármacos , Feminino , Fulvestranto , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Humanos , Células Tumorais Cultivadas/efeitos dos fármacos
10.
J Med Chem ; 44(12): 2015-26, 2001 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-11384246

RESUMO

5-Dialkylaminosulfonylisatins have been identified as potent, nonpeptide inhibitors of caspases 3 and 7. The most active compound within this series (34) inhibited caspases 3 and 7 in the 2-6 nM range and exhibited approximately 1000-fold selectivity for caspases 3 and 7 versus a panel of five other caspases (1, 2, 4, 6, and 8) and was at least 20-fold more selective versus caspase 9. Sequence alignments of the active site residues of the caspases strongly suggest that the basis of this selectivity is due to binding in the S2 subsite comprised of residues Tyr204, Trp206, and Phe256 which are unique to caspases 3 and 7. These compounds inhibit apoptosis in three cell-based models: human Jurkat T cells, human chondrocytes, and mouse bone marrow neutrophils.


Assuntos
Inibidores de Caspase , Inibidores de Cisteína Proteinase/síntese química , Isatina/análogos & derivados , Isatina/síntese química , Sulfonamidas/síntese química , Animais , Antineoplásicos/síntese química , Antineoplásicos/química , Antineoplásicos/toxicidade , Apoptose/efeitos dos fármacos , Caspase 3 , Caspase 7 , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Condrócitos/citologia , Condrócitos/efeitos dos fármacos , Inibidores de Cisteína Proteinase/química , Inibidores de Cisteína Proteinase/farmacologia , Desenho de Fármacos , Humanos , Isatina/química , Isatina/farmacologia , Células Jurkat , Cinética , Camundongos , Modelos Moleculares , Conformação Molecular , Neutrófilos/citologia , Neutrófilos/efeitos dos fármacos , Neutrófilos/fisiologia , Proteínas Recombinantes/antagonistas & inibidores , Relação Estrutura-Atividade , Sulfonamidas/química , Sulfonamidas/farmacologia
11.
EMBO J ; 20(12): 3101-13, 2001 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-11406587

RESUMO

The protease granzyme B (GrB) plays a key role in the cytocidal activity during cytotoxic T lymphocyte (CTL)-mediated programmed cell death. Multiple caspases have been identified as direct substrates for GrB, suggesting that the activation of caspases constitutes an important event during CTL-induced cell death. However, recent studies have provided evidence for caspase-independent pathway(s) during CTL-mediated apoptosis. In this study, we demonstrate caspase-independent and direct cleavage of the 45 kDa unit of DNA fragmentation factor (DFF45) by GrB both in vitro and in vivo. Using a novel and selective caspase-3 inhibitor, we show the ability of GrB to process DFF45 directly and mediate DNA fragmentation in the absence of caspase-3 activity. Furthermore, studies with DFF45 mutants reveal that both caspase-3 and GrB share a common cleavage site, which is necessary and sufficient to induce DNA fragmentation in target cells during apoptosis. Together, our data suggest that CTLs possess alternative mechanism(s) for inducing DNA fragmentation without the requirement for caspases.


Assuntos
Caspases/metabolismo , Fragmentação do DNA , Desoxirribonucleases/metabolismo , Proteínas Nucleares/metabolismo , Proteínas/metabolismo , Serina Endopeptidases/metabolismo , Apoptose , Proteínas Reguladoras de Apoptose , Sítios de Ligação , Caspase 3 , Inibidores de Caspase , Ativação Enzimática , Granzimas , Humanos , Células Jurkat , Estrutura Molecular , Proteínas Nucleares/química , Proteínas/química , Especificidade por Substrato
12.
Bone ; 28(5): 465-73, 2001 May.
Artigo em Inglês | MEDLINE | ID: mdl-11344045

RESUMO

Bisphosphonates inhibit osteoclast-mediated bone resorption by mechanisms that have only recently become clear. Whereas nitrogen-containing bisphosphonates affect osteoclast function by preventing protein prenylation (especially geranylgeranylation), non-nitrogen-containing bisphosphonates have a different molecular mechanism of action. In this study, we demonstrate that nitrogen-containing bisphosphonates (risedronate, alendronate, pamidronate, and zoledronic acid) and non-nitrogen-containing bisphosphonates (clodronate and etidronate) cause apoptosis of rabbit osteoclasts, human osteoclastoma-derived osteoclasts, and human osteoclast-like cells generated in cultures of bone marrow in vitro. Osteoclast apoptosis was shown to involve characteristic morphological changes, loss of mitochondrial membrane potential, and the activation of caspase-3-like proteases capable of cleaving peptide substrates with the sequence DEVD. Caspase-3-like activity could be visualized in unfixed, dying osteoclasts and osteoclast-like cells using a cell-permeable, fluorogenic substrate. Bisphosphonate-induced osteoclast apoptosis was dependent on caspase activation, because apoptosis resulting from alendronate, clodronate, or zoledronic acid treatment was suppressed by zVAD-fmk, a broad-range caspase inhibitor, or by SB-281277, a specific isatin sulfonamide inhibitor of caspase-3/-7. Furthermore, caspase-3 (but not caspase-6 or caspase-7) activity could be detected and quantitated in lysates from purified rabbit osteoclasts, whereas the p17 fragment of active caspase-3 could be detected in human osteoclast-like cells by immunofluorescence staining. Caspase-3, therefore, appears to be the major effector caspase activated in osteoclasts by bisphosphonate treatment. Caspase activation and apoptosis induced by nitrogen-containing bisphosphonates are likely to be the consequence of the loss of geranylgeranylated rather than farnesylated proteins, because the ability to cause apoptosis and caspase activation was mimicked by GGTI-298, a specific inhibitor of protein geranylgeranylation, whereas FTI-277, a specific inhibitor of protein farnesylation, had no effect on apoptosis or caspase activity.


Assuntos
Apoptose/fisiologia , Doenças Ósseas Metabólicas/tratamento farmacológico , Osso e Ossos/efeitos dos fármacos , Caspases/efeitos dos fármacos , Difosfonatos/farmacologia , Osteoclastos/efeitos dos fármacos , Animais , Animais Recém-Nascidos , Apoptose/efeitos dos fármacos , Doenças Ósseas Metabólicas/enzimologia , Doenças Ósseas Metabólicas/fisiopatologia , Osso e Ossos/enzimologia , Osso e Ossos/fisiopatologia , Caspase 3 , Caspase 6 , Caspase 7 , Caspases/metabolismo , Inibidores Enzimáticos/farmacologia , Corantes Fluorescentes/farmacocinética , Humanos , Nitrogênio/metabolismo , Osteoclastos/citologia , Osteoclastos/enzimologia , Prenilação de Proteína/efeitos dos fármacos , Prenilação de Proteína/fisiologia , Coelhos , Células Tumorais Cultivadas/citologia , Células Tumorais Cultivadas/efeitos dos fármacos , Células Tumorais Cultivadas/enzimologia
13.
Heart ; 85(5): 533-8, 2001 May.
Artigo em Inglês | MEDLINE | ID: mdl-11303005

RESUMO

OBJECTIVE: To develop and test a cardiac prevention and rehabilitation programme for achieving sustained lifestyle, risk factor, and therapeutic targets in patients presenting for the first time with exertional angina, acute coronary syndromes, or coronary revascularisation. DESIGN: A descriptive study. SETTING: A hospital based 12 week outpatient programme. INTERVENTIONS: A multiprofessional family based programme of lifestyle and risk factor modification. MAIN OUTCOME MEASURES: Non-smoking status, body mass index, blood pressure, plasma cholesterol, use of prophylactic drugs. RESULTS: 158 patients (82% of 194 possible cases) were recruited over 15 months, with 72% completing the programme. Targets for achieving non-smoking status, blood pressure < 140/90 mm Hg, and total cholesterol < 4.8 mmol/l were achieved in 92%, 73%, and 62%, respectively, and the proportion on aspirin, beta blockers, and lipid lowering treatment was 95%, 58%, and 64% on referral back to general practice for continuing care. CONCLUSIONS: A comprehensive cardiac prevention and rehabilitation programme can be offered to all patients presenting for the first time with coronary heart disease, including those with exertional angina who are normally managed in primary care. Lifestyle, risk factor, and therapeutic targets can be successfully achieved in most patients with such a hospital based programme.


Assuntos
Doença das Coronárias/prevenção & controle , Promoção da Saúde/métodos , Estilo de Vida , Adulto , Idoso , Idoso de 80 Anos ou mais , Assistência Ambulatorial/métodos , Pressão Sanguínea , Índice de Massa Corporal , Doença das Coronárias/fisiopatologia , Doença das Coronárias/reabilitação , Inglaterra , Feminino , Seguimentos , Comportamentos Relacionados com a Saúde , Humanos , Masculino , Pessoa de Meia-Idade , Cooperação do Paciente , Avaliação de Programas e Projetos de Saúde , Fatores de Risco , Abandono do Hábito de Fumar , Resultado do Tratamento
14.
Drug Discov Today ; 6(2): 85-91, 2001 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-11166256

RESUMO

Caspases are essential for apoptosis. A crucial question regarding the role(s) of these proteases is whether the selective inhibition of an effector caspase will prevent cell death. We have identified potent, selective non-peptide inhibitors of the effector caspases 3 and 7. Apoptosis can be inhibited and cell functionality maintained using an inhibitor selective for caspases 3 and 7. This has important therapeutic implications and the potential to generate novel anti-apoptotic strategies in diseases that involve dysregulated apoptosis.

15.
Expert Opin Emerg Drugs ; 6(1): 137-54, 2001 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-15989501

RESUMO

Accelerated bone loss secondary to loss of ovarian function at menopause is well recognised as a major risk factor for osteoporotic fractures in postmenopausal women. Postmenopausal bone loss can be prevented or arrested by oestrogen replacement therapy (ERT). It has also been reported that ERT protects against cardiovascular disease by improving the serum lipid profile, however there are mixed reports concerning these benefits. Unopposed ERT causes an unacceptable increase in the risk of endometrial cancer and proliferative effects in mammary tissue resulting in an increased risk of breast cancer. While this can be counteracted by combining ERT with a low-dose of a progestin, withdrawal bleeding and the continuing uncertainty about the effect of oestrogen on the risk of breast cancer contribute to poor compliance for long-term use. Because of the known and suspected risks of oestrogen therapy it has been estimated that in the US < 40% of women on ERT will continue treatment beyond one year. An ideal therapy would retain the desirable skeletal and cardiovascular effects of oestrogen, lack oestrogenic activity on the endometrium and reduce the incidence of breast cancer. The concept of selective oestrogen receptor modulation (SERM) has been demonstrated for a number of compounds including tamoxifen, raloxifene, droloxifene, GW-5638 and levormeloxifene. However, the clinical utility of these agents will depend on the profile of tissue-specific effects and the extent to which they are translated into in vivo efficacy. A SERM is defined as a compound that has oestrogen agonism on one or more of the desired target tissues, such as bone or liver, and has antagonism and/or minimal agonism (i.e., clinically insignificant) in reproductive tissue, such as the breast or uterus. Although tamoxifen acts as a SERM, it is also associated with an increased incidence (4% gynaecological symptoms greater than placebo control) of endometrial cancer. Indeed, there have been a number of mechanistic-based studies to explain the increased incidence of endometrial carcinomas in tamoxifen treated patients, which provide an in vitro insight into the adverse clinical observations in vivo. Attempts to improve on the pharmacological profile of tamoxifen have resulted in compounds that differ in their oestrogen agonist/antagonist characteristics, including the pure oestrogen antagonists. This suggests that it may be possible to develop a molecule with a desired profile of tissue-specific agonist/antagonist activities by establishing bone and cardiovascular protective effects but having no effects (or even behaving as an antagonist) in the reproductive tissues.

16.
Eur J Pharmacol ; 433(2-3): 135-40, 2001 Dec 21.
Artigo em Inglês | MEDLINE | ID: mdl-11755144

RESUMO

In the present study, we have used an in vitro model of apoptosis using primary human renal proximal tubular epithelial (RPTE) cells to investigate the mechanisms involved in renal cell apoptosis. Treatment of RPTE cells with okadaic acid for 24-48 h induced apoptosis in a concentration-dependent manner. Apoptosis was accompanied by the activation of the p38 mitogen-activated protein kinase (MAPK) pathway followed by the activation of caspase-9, -3, and -7. The induction of caspase activity correlated with the proteolytic cleavage of beta-catenin, suggesting that beta-catenin is a caspase substrate. The caspase inhibitor, Z-Val-Ala-Asp-fluoromethylketone (Z-VAD-fmk), resulted in a dose-dependent inhibition of apoptosis and beta-catenin cleavage. These data suggest that okadaic acid-induced apoptosis is p38 MAPK and caspase-dependent and that proteolytic cleavage of beta-catenin by caspases is likely to be a downstream molecular event associated with the morphological and cytoskeletal changes induced during apoptosis.


Assuntos
Apoptose , Caspases/fisiologia , Túbulos Renais Proximais/citologia , Transativadores , Clorometilcetonas de Aminoácidos/farmacologia , Proteínas do Citoesqueleto/metabolismo , Humanos , Proteínas Quinases Ativadas por Mitógeno/fisiologia , Ácido Okadáico/farmacologia , Oligopeptídeos/farmacologia , beta Catenina , Proteínas Quinases p38 Ativadas por Mitógeno
17.
Eur J Cancer ; 36 Suppl 4: S63-4, 2000 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-11056323

RESUMO

Idoxifene and raloxifene are selective oestrogen receptor modulators (SERMs) that by definition exhibit tissue-specific agonist or antagonist properties via interactions with the oestrogen receptor (ER). Idoxifene acts as an oestrogen agonist in osteoblastic cells via an ER/ERE-mediated mechanism. In contrast, raloxifene is an antagonist via the ERE in osteoblastic cells. Like the pure antagonist ICI 182,780, raloxifene inhibited the potent agonist activity of both 17beta-oestradiol and idoxifene through the ERE whereas idoxifene had no effect on the agonist activity of 17beta-oestradiol via the ERE. In breast cancer cells, both raloxifene and idoxifene were potent antagonists of ERE-mediated 17beta-oestradiol action suggesting an ERE-dependent mechanism of action for both ligands in these cells. Therefore, these SERMs exhibit cell-specific ERE-dependent and -independent mechanisms of action.


Assuntos
Antagonistas de Estrogênios/farmacologia , Estrogênios/metabolismo , Cloridrato de Raloxifeno/farmacologia , Moduladores Seletivos de Receptor Estrogênico/farmacologia , Tamoxifeno/análogos & derivados , Tamoxifeno/farmacologia , Neoplasias da Mama/metabolismo , Divisão Celular , Feminino , Humanos , Proteínas Repressoras , Células Tumorais Cultivadas/efeitos dos fármacos
18.
Arch Biochem Biophys ; 381(2): 205-12, 2000 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-11032407

RESUMO

A bovine cartilage explant system was used to evaluate the effects of injurious compression on chondrocyte apoptosis and matrix biochemical and biomechanical properties within intact cartilage. Disks of newborn bovine articular cartilage were compressed in vitro to various peak stress levels and chondrocyte apoptotic cell death, tissue biomechanical properties, tissue swelling, glycosaminoglycan loss, and nitrite levels were quantified. Chondrocyte apoptosis occurred at peak stresses as low as 4.5 MPa and increased with peak stress in a dose-dependent manner. This increase in apoptosis was maximal by 24 h after the termination of the loading protocol. At high peak stresses (>20 MPa), greater than 50% of cells apoptosed. When measured in uniaxial confined compression, the equilibrium and dynamic stiffness of explants decreased with the severity of injurious load, although this trend was not significant until 24-MPa peak stress. In contrast, the equilibrium and dynamic stiffness measured in radially unconfined compression decreased significantly after injurious stresses of 12 and 7 MPa, respectively. Together, these results suggested that injurious compression caused a degradation of the collagen fibril network in the 7- to 12-MPa range. Consistent with this hypothesis, injurious compression caused a dose-dependent increase in tissue swelling, significant by 13-MPa peak stress. Glycosaminoglycans were also released from the cartilage in a dose-dependent manner, significant by 6- to 13-MPa peak stress. Nitrite levels were significantly increased above controls at 20-MPa peak stress. Together, these data suggest that injurious compression can stimulate cell death as well as a range of biomechanical and biochemical alterations to the matrix and, possibly, chondrocyte nitric oxide expression. Interestingly, chondrocyte programmed cell death appears to take place at stresses lower than those required to stimulate cartilage matrix degradation and biomechanical changes. While chondrocyte apoptosis may therefore be one of the earliest responses to tissue injury, it is currently unclear whether this initial cellular response subsequently drives cartilage matrix degradation and changes in the biomechanical properties of the tissue.


Assuntos
Apoptose , Cartilagem Articular/lesões , Cartilagem Articular/patologia , Condrócitos/patologia , Animais , Animais Recém-Nascidos , Cartilagem Articular/metabolismo , Bovinos , Colágeno/metabolismo , Marcação In Situ das Extremidades Cortadas , Técnicas In Vitro , Cinética , Estresse Mecânico
19.
Am J Physiol Cell Physiol ; 279(5): C1550-7, 2000 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-11029302

RESUMO

Raloxifene and idoxifene are selective estrogen receptor modulators (SERMs) that exhibit tissue-specific agonist or antagonist properties via interactions with the estrogen receptor (ER). Both compounds are similarly osteoprotective in the ovariectomized rat in vivo as assessed by measurement of bone mineral density, urinary pyridinium cross-links, and serum osteocalcin, suggesting a similar mechanism of action. However, we have identified a fundamental difference in this mechanism via the estrogen response element (ERE) in osteoblast-like cells. With the use of ERE-luciferase reporter constructs, raloxifene, like the complete ER-antagonist ICI-182780, acts as an antagonist via the ERE in osteoblastic cells. In contrast, idoxifene, like 17beta-estrogen itself and 4-OH-tamoxifen, acts as an agonist in osteoblastic cells via an ER/ERE-mediated mechanism. Both ICI-182780 and raloxifene inhibited the ERE-dependent agonist activity of 17beta-estradiol and idoxifene in osteoblastic cells. In contrast, in breast cells, raloxifene, idoxifene, 4-OH-tamoxifen, and ICI-182780 had no agonist activity and, indeed, raloxifene and idoxifene were potent antagonists of ERE-mediated 17beta-estradiol action, indicating an ERE-dependent mode of action in these cells. Although these SERMs exhibit a similar antagonist activity profile in breast cells, they can be distinguished mechanistically in osteoblastic cells.


Assuntos
Estradiol/análogos & derivados , Glândulas Mamárias Animais/metabolismo , Osteoblastos/metabolismo , Receptores de Estrogênio/metabolismo , Tamoxifeno/análogos & derivados , Animais , Células Cultivadas , Estradiol/farmacologia , Antagonistas de Estrogênios/farmacologia , Feminino , Fulvestranto , Ligantes , Glândulas Mamárias Animais/citologia , Glândulas Mamárias Animais/efeitos dos fármacos , Osteoblastos/efeitos dos fármacos , Cloridrato de Raloxifeno/farmacologia , Ratos , Ratos Sprague-Dawley , Receptores de Estrogênio/agonistas , Receptores de Estrogênio/genética , Elementos de Resposta/fisiologia , Tamoxifeno/farmacologia
20.
J Orthop Res ; 18(3): 356-63, 2000 May.
Artigo em Inglês | MEDLINE | ID: mdl-10937621

RESUMO

Apoptosis was induced in a human chondrocyte cell line, T/C 28a4, by treatment with various stimuli, including camptothecin, tumor necrosis factor-alpha, staurosporine, okadaic acid, and reduced serum conditions. All stimuli induced a cytosolic DEVDase activity, coincident with apoptosis. Caspase activities in the lysates were characterized and quantitated with peptide cleavage profiles. To confirm that the results were not related to the immortalized nature of the cell line, primary human chondrocytes also were shown to undergo apoptosis under similar conditions, which resulted in increased cytosolic DEVDase activity. There was little or no caspase-1 (interleukin-1beta-converting enzyme) or caspase-8-like activity in the apoptotic cells. In all cases, the irreversible nonselective caspase inhibitor, Z-VAD-FMK, and the caspase-3-selective inhibitor, Ac-DMQD-CHO, inhibited DEVDase activity and apoptosis, whereas the caspase-1-selective inhibitor, Ac-YVAD-CHO, had no effect. Human chondrocytes were stably and transiently transfected with a type-II collagen gene (COL2A1) regulatory sequence driving a luciferase reporter as a specific marker of chondrocyte gene expression. Treatment of the cells with camptothecin or tumor necrosis factor-alpha plus cycloheximide significantly inhibited COL2A1 transcriptional activity. Significantly, cotreatment with Z-VAD-FMK or Ac-DMQD-CHO maintained COL2A1-reporter gene activity, indicating that the prevention of apoptosis by caspase-3 inhibition was sufficient to maintain cell functionality as assessed by the retention of type-II collagen promoter activity.


Assuntos
Apoptose , Caspases/fisiologia , Condrócitos/fisiologia , Clorometilcetonas de Aminoácidos/farmacologia , Caspase 3 , Inibidores de Caspase , Linhagem Celular , Colágeno/genética , Humanos , Oligopeptídeos/farmacologia , Regiões Promotoras Genéticas , Regulação para Cima
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