Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 12 de 12
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Environ Manage ; 50(5): 914-28, 2012 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-22961614

RESUMO

Managers of the nearly 0.5 million ha of public lands in North and South Dakota, USA rely heavily on manual measurements of canopy height in autumn to ensure conservation of grassland structure for wildlife and forage for livestock. However, more comprehensive assessment of vegetation structure could be achieved for mixed-grass prairie by integrating field survey, topographic position (summit, mid and toeslope) and spectral reflectance data. Thus, we examined the variation of mixed-grass prairie structural attributes (canopy leaf area, standing crop mass, canopy height, nitrogen, and water content) and spectral vegetation indices (VIs) with variation in topographic position at the Grand River National Grassland (GRNG), South Dakota. We conducted the study on a 36,000-ha herbaceous area within the GRNG, where randomly selected plots (1 km(2) in size) were geolocated and included summit, mid and toeslope positions. We tested for effects of topographic position on measured vegetation attributes and VIs calculated from Landsat TM and Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) data collected in July 2010. Leaf area, standing crop mass, canopy height, nitrogen, and water content were lower at summits than at toeslopes. The simple ratio of Landsat Band 7/Band 1 (SR71) was the VI most highly correlated with canopy standing crop and height at plot and landscape scales. Results suggest field and remote sensing-based grassland assessment techniques could more comprehensively target low structure areas at minimal expense by layering modeled imagery over a landscape stratified into topographic position groups.


Assuntos
Monitoramento Ambiental/métodos , Folhas de Planta , Poaceae , Modelos Teóricos , Nitrogênio/análise , South Dakota , Água/análise
2.
Cancer Res ; 61(19): 7122-9, 2001 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-11585744

RESUMO

1alpha, 25-Dihydroxyvitamin D(3) [1alpha, 25-(OH)(2)D(3)] is recognized to have significant antiproliferative effects on certain prostatic carcinoma (PC) cell lines, although the precise mechanisms of action remain in question. We have evaluated the role of the cell cycle-dependent kinase inhibitor p21. In the PC cell lines ALVA-31 and LNCaP, 1alpha, 25-(OH)(2)D(3) inhibits growth and induces both p21 mRNA and protein levels. Growth inhibition of ALVA-31 cells was abolished by stable transfection with a p21 antisense construct. This effect was not attributable to a reduction in functional vitamin D receptors as measured by transcriptional activity with a luciferase-vitamin D response element reporter construct. Therefore, increased p21 expression appears necessary to mediate the antiproliferative effects of this hormone in ALVA-31 cells. Cell lines that are insensitive to the growth inhibitory properties of 1alpha, 25-(OH)(2)D(3) failed to up-regulate p21 expression after hormone treatment; these include sublines of ALVA-31 as well as the cell lines TSU-Pr1 and JCA-1. In the latter two lines, adenovirus-mediated expression of a sense p21 cDNA significantly reduced their proliferation as compared with a control adenoviral construct. This suggests that the signaling pathway downstream of p21 is intact in TSU-Pr1 and JCA-1 cells, although p21 expression appears unregulated by 1alpha, 25-(OH)(2)D(3). We propose a model in which the antiproliferative effect of 1alpha, 25-(OH)(2)D(3) on PC cells is mediated through increased p21 expression. Elucidation of why this effect is absent in select cell lines may provide valuable insight into the variability of responses observed in PC patients treated with vitamin D.


Assuntos
Calcitriol/farmacologia , Ciclinas/biossíntese , Inibidores do Crescimento/farmacologia , Neoplasias da Próstata/metabolismo , Contagem de Células , Ciclo Celular/efeitos dos fármacos , Divisão Celular/efeitos dos fármacos , Inibidor de Quinase Dependente de Ciclina p21 , Ciclinas/genética , DNA Antissenso/genética , DNA Antissenso/farmacologia , Relação Dose-Resposta a Droga , Humanos , Masculino , Neoplasias da Próstata/tratamento farmacológico , Neoplasias da Próstata/genética , Neoplasias da Próstata/patologia , Transfecção , Células Tumorais Cultivadas , Regulação para Cima/efeitos dos fármacos
3.
Clin Cancer Res ; 5(3): 695-703, 1999 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-10100724

RESUMO

The majority of men who die from prostate cancer (PC) have hormone-refractory disease. To date, chemotherapeutic agents have had little or no impact on the survival of such patients. To explore a new approach for the treatment of hormone-refractory PC, we examined the combination effects of cis- or carboplatin with vitamin D. 1alpha,25-Dihydroxyvitamin D3 (1alpha,25(OH)2D3) and its synthetic analogue, Ro 25-6760, have an antiproliferative effect on some prostate cancer cell lines. Consequently, the growth-inhibitory effects of the drugs were measured, both singularly and in combination with cis- or carboplatin, on PC cells. Our results show that although each of the drugs alone displayed antiproliferative activity, the growth inhibition of PC cells was further enhanced by the combination of 1alpha,25(OH)2D3 or Ro 25-6760 and either platinum agent. The greatest enhancement of inhibition occurred using smaller concentrations of the platinum compound in combination with higher concentrations of 1alpha,25(OH)2D3. Isobologram analysis revealed that 1alpha,25(OH)2D3 and platinum acted in a synergistic manner to inhibit the growth of PC cells. Our findings suggest that there is potential clinical value in combining 1alpha,25(OH)2D3 with platinum compounds for the treatment of advanced-stage human PC.


Assuntos
Antineoplásicos/farmacologia , Calcitriol/farmacologia , Carboplatina/farmacologia , Cisplatino/farmacologia , Neoplasias da Próstata/patologia , Anticarcinógenos/farmacologia , Ciclo Celular/efeitos dos fármacos , Divisão Celular/efeitos dos fármacos , Colecalciferol/análogos & derivados , Colecalciferol/farmacologia , Relação Dose-Resposta a Droga , Sinergismo Farmacológico , Humanos , Masculino , Platina/farmacologia , Células Tumorais Cultivadas
4.
Clin Cancer Res ; 3(8): 1331-8, 1997 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-9815816

RESUMO

Numerous studies have indicated that the secosteroid hormone 1alpha, 25-dihydroxyvitamin D3 protects against the development of clinical prostate cancer (PC). Whether this hormone also has therapeutic potential for patients with advanced PC has not yet been evaluated. Several synthetic vitamin D analogues are now available that have reduced hypercalcemic effects and yet effectively induce differentiation in some cell types. For these reasons, these analogues may be safer and more effective for cancer therapy than the natural hormone. In the current study, 13 such analogues were screened for their abilities to inhibit the growth of PC cell lines. Three of the most consistently effective analogues (Ro 23-7553, Ro 24-5531, and Ro 25-6760) were then chosen for further analysis. Growth studies using clones of the JCA-1 cell line that were transfected with the vitamin D receptor cDNA indicate that the antiproliferative effects of these analogues require vitamin D receptor expression. Furthermore, these three analogues induce the secretion of prostate-specific acid phosphatase and prostate-specific antigen (two markers of the differentiated prostatic phenotype) in the cell line LNCaP. These in vitro studies suggest that Ro 23-7553, Ro 24-5531, and Ro 25-6760 should be further evaluated as therapeutic agents for the treatment of PC.


Assuntos
Fosfatase Ácida/genética , Antineoplásicos/toxicidade , Calcitriol/análogos & derivados , Colecalciferol/análogos & derivados , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Antígeno Prostático Específico/genética , Receptores de Calcitriol/fisiologia , Vitamina D/análogos & derivados , Vitamina D/toxicidade , Fosfatase Ácida/biossíntese , Calcitriol/toxicidade , Divisão Celular/efeitos dos fármacos , Colecalciferol/toxicidade , Indução Enzimática , Humanos , Masculino , Próstata/enzimologia , Antígeno Prostático Específico/biossíntese , Receptores de Calcitriol/efeitos dos fármacos , Proteínas Recombinantes/metabolismo , Relação Estrutura-Atividade , Transfecção , Células Tumorais Cultivadas
5.
Am J Pathol ; 150(6): 2009-18, 1997 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-9176394

RESUMO

Application of differential display to the comparison of androgen-stimulated and unstimulated human prostate carcinoma cell line LNCaP identified androgen induction of the L-plastin gene, which encodes an actin-binding protein isoform. Further investigation demonstrated that L-plastin expression in LNCaP cells is up-regulated by both dihydrotestosterone and estradiol. This induction of expression is detected as early as 2 hours after addition of steroids to the cell culture. L-plastin expression is also detected in other prostate carcinoma cell lines by reverse transcriptase polymerase chain reaction and immunohistochemistry but not in the single normal adult prostate epithelial cell line that is available to us. Analysis of multiple primary prostatic tumor tissues as well as normal and tumor tissues of the same prostate gland showed that tumor tissues exhibit a higher level of expression as compared with the normal tissues. Immunohistochemical study using anti-L-plastin antiserum on normal and carcinomatous prostate tissues showed a very striking difference in the staining patterns. Positive staining was seen in the fibromuscular stroma in normal prostates but not in the glandular epithelial cells. In contrast, strong staining was seen predominantly within the carcinomatous glandular epithelial cells. Taken together, these results suggest that the expression of L-plastin in prostatic epithelial cells is linked to the malignant state and that, once expressed in carcinomas, its expression is regulated by steroid hormone receptors.


Assuntos
Di-Hidrotestosterona/farmacologia , Regulação da Expressão Gênica , Fosfoproteínas/metabolismo , Próstata/metabolismo , Neoplasias da Próstata/metabolismo , Western Blotting , Estradiol/farmacologia , Regulação da Expressão Gênica/efeitos dos fármacos , Humanos , Imuno-Histoquímica , Masculino , Glicoproteínas de Membrana , Proteínas dos Microfilamentos , Dados de Sequência Molecular , Próstata/efeitos dos fármacos , Transdução de Sinais , Fatores de Tempo , Células Tumorais Cultivadas/efeitos dos fármacos
6.
J Steroid Biochem Mol Biol ; 58(3): 277-88, 1996 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-8836163

RESUMO

Epidemiological data suggest that vitamin D3, obtained from dietary sources and sunlight exposure, protects against mortality from prostate cancer (PC). In agreement with this, the most active vitamin D metabolite 1 alpha,25-dihydroxyvitamin D3 [1,25(OH)2 D3] regulates the growth and differentiation of several human PC cell lines. Both genomic and non-genomic signalling pathways for 1,25(OH)2 D3 have been reported, although the mechanism of action in PC cells has not been defined. We now provide data supporting an active role for the nuclear vitamin D receptor (VDR) in mediating the growth-inhibitory effects of 1,25(OH)2 D3 on these cells. In the VDR-rich cell line ALVA-31, the observed changes in growth by 1,25(OH)2 D3 are preceded by significant changes in VDR mRNA expression. In contrast, the cell line JCA-1, containing few VDRs, fails to show both early changes in VDR gene expression and later changes in growth with 1,25(OH)2 D3. To assess the role of the VDR more directly, transfection studies were pursued. ALVA-31 cells were stably transfected with an antisense VDR cDNA construct in an attempt to reduce VDR expression. Antisense mRNA expression among clones was associated with: (a) reduced or abolished sensitivity to the effects of 1,25(OH)2 D3 on growth; (b) decreased numbers of VDRs per cell, as measured by radiolabelled-ligand binding; and (c) a lack of induction of the VDR-regulated enzyme 24-hydroxylase in response to 1,25(OH)2 D3. From these studies we conclude that the antiproliferative effects of 1,25(OH)2 D3 require expression of the nuclear VDR in this system.


Assuntos
Calcitriol/farmacologia , Carcinoma/metabolismo , Neoplasias da Próstata/metabolismo , Receptores de Calcitriol/biossíntese , Carcinoma/patologia , Divisão Celular/efeitos dos fármacos , DNA Antissenso/genética , Regulação Neoplásica da Expressão Gênica , Técnicas de Transferência de Genes , Humanos , Masculino , Neoplasias da Próstata/patologia , Receptores de Calcitriol/genética , Células Tumorais Cultivadas
7.
Endocrinology ; 137(5): 1554-61, 1996 May.
Artigo em Inglês | MEDLINE | ID: mdl-8612485

RESUMO

The secosteroid hormone 1 alpha, 25-dihydroxyvitamin D3 [1,25-(OH)2D3] has been found to regulate the growth and differentiation of human prostate cancer cells, although the precise mechanisms mediating these effects have not been defined. 1,25-(OH)2D3 is capable of acting through both nongenomic signaling pathways involving a membrane-associated receptor and genomic pathways involving the nuclear vitamin D receptor (VDR). The primary purpose of this study was to directly evaluate the role of the nuclear VDR in mediating the growth inhibitory effects of 1,25-(OH)2D3 on human prostate cancer cells. The cell line JCA-1 was used because it fails to express detectable number of VDRs and is not measurable affected by 1,25-(OH)2D3 in growth studies. These cells were stably transfected with a wild-type VDR complementary DNA construct producing the following results: 1) the expression of high affinity nuclear VDRs, 2) the dose-dependent inhibition of growth by 1,25-(OH)2D3, and 3) a significant increase in 24-hydroxylase up-regulation by 1,25-(OH)2D3 compared to that in controls. These data indicate that nuclear VDR expression is sufficient to mediate the antiproliferative effects of 1,25-(OH)2D3 on prostate cancer cells. In addition, because the stereoisomer 1 beta, 25-dihydroxyvitamin D3 failed to block these antiproliferative effects, we conclude that nongenomic mechanisms of action are not requisite for growth inhibition by 1,25-(OH)2D3.


Assuntos
Calcitriol/farmacologia , Núcleo Celular/metabolismo , Sistema Enzimático do Citocromo P-450 , Expressão Gênica , Neoplasias da Próstata/genética , Receptores de Calcitriol/genética , Transdução de Sinais/efeitos dos fármacos , Sequência de Bases , Calcitriol/administração & dosagem , Divisão Celular/efeitos dos fármacos , Relação Dose-Resposta a Droga , Humanos , Masculino , Dados de Sequência Molecular , Estereoisomerismo , Esteroide Hidroxilases/metabolismo , Transfecção , Células Tumorais Cultivadas , Vitamina D3 24-Hidroxilase
8.
Angle Orthod ; 66(3): 189-94, 1996.
Artigo em Inglês | MEDLINE | ID: mdl-8805913

RESUMO

The purpose of this study was to compare the amplitude of facial motion obtained using three-dimensional (3-D) and two-dimensional (2-D) methods. The amplitude of motion of fifteen facial landmarks during five maximal animations (smile, lip-purse, grimace, eye closure, and cheek-puff) was quantified in 3-D and 2-D using a video-based system. Results showed that the 3-D amplitudes were significantly larger than the 2-D amplitudes, especially for landmarks on the lower face during the smile animation. In the latter instance, the 2-D amplitudes underestimated the 3-D amplitudes by as much as 43%. The difference between 3-D and 2-D amplitudes was greater for 2-D amplitudes obtained from one camera rather than from multiple cameras. The results suggest that a 2-D analysis may not be adequate to assess facial motion during maximal animations, and that a 3-D analysis may be more appropriate for detecting clinical differences in facial function.


Assuntos
Cefalometria/métodos , Face/fisiologia , Expressão Facial , Movimento , Adulto , Criança , Fissura Palatina/fisiopatologia , Músculos Faciais/fisiologia , Humanos , Fotogrametria , Valores de Referência , Gravação em Vídeo/instrumentação , Gravação em Vídeo/métodos
9.
Angle Orthod ; 66(3): 195-8, 1996.
Artigo em Inglês | MEDLINE | ID: mdl-8805914

RESUMO

Reliable methods of quantifying functional impairment of the craniofacial region are sorely lacking. The purpose of this study was to test the reliability of a three-dimensional method for assessing the functional repertoire of the face. Subjects were instructed to perform repeated sequences of five maximal facial animations. Facial motions were captured by three 60-Hz video cameras, and three-dimensional maximum motion amplitudes were calculated. Student's t-test and Pearson product-moment correlation coefficients were used to test for significant differences between repetitions. The results show moderate to excellent reliability of the amplitude of motion for the landmarks over all animations. For each specific animation, certain landmarks demonstrated excellent reliability of motion.


Assuntos
Cefalometria/métodos , Face/fisiologia , Expressão Facial , Movimento , Adulto , Criança , Humanos , Fotogrametria , Valores de Referência , Reprodutibilidade dos Testes , Estatísticas não Paramétricas , Gravação em Vídeo/instrumentação , Gravação em Vídeo/métodos
10.
Blood ; 86(10): 3685-91, 1995 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-7579334

RESUMO

The clinical relevance of antiphospholipid antibodies (APLA) in patients without systemic lupus erythematosus who have venous thromboembolism (VTE) in unknown. Limited evidence suggests that there is an association between the presence of APLA and both initial and recurrent episodes of VTE and that patients with APLA and VTE are resistant to warfarin therapy. Unselected patients with a first episode of clinically suspected deep vein thrombosis or pulmonary embolism were evaluated with objective tests for VTE and with laboratory tests for APLA; the latter included tests for the lupus anticoagulant (LA) and anticardiolipin antibodies (ACLA). Patients with VTE were treated with anticoagulant therapy and observed during and after discontinuation of anticoagulants for symptomatic recurrence of VTE. There was a strong association between LA and VTE (odds ratio, 9.4; 95% confidence interval [CI], 2.1 to 46.2) and 9 to 65 (14%; 95% CI, 7% to 25%) patients with VTE had LA. There was no association between the presence of ACLA and VTE (odds ratio, 0.7; 95%CI, 0.3 to 1.7) because of the high frequency of positive ACLA assays in patients without VTE. None of the 16 patients with VTE and APLA developed recurrent VTE while receiving warfarin therapy. There was no difference in rates of recurrent VTE in patients with or without APLA after anticoagulant therapy was discontinued. The strong association between LA and VTE suggests that testing for LA in patients with VTE is useful. The measurement of ACLA in patients with VTE has no clinical usefulness because the results are abnormal in a high proportion of patients without VTE. Although the presence of APLA in patients with VTE was not associated with resistance to a conventional intensity of warfarin or an increased risk of recurrent VTE after discontinuation of warfarin, a larger study should address these issues in a subgroup of patients with VTE and LA.


Assuntos
Anticorpos Antifosfolipídeos/análise , Síndrome Antifosfolipídica/complicações , Doenças Autoimunes/complicações , Embolia Pulmonar/etiologia , Tromboflebite/etiologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Anticorpos Anticardiolipina/análise , Anticoagulantes/uso terapêutico , Feminino , Humanos , Inibidor de Coagulação do Lúpus/análise , Masculino , Pessoa de Meia-Idade , Ontário/epidemiologia , Valor Preditivo dos Testes , Estudos Prospectivos , Embolia Pulmonar/tratamento farmacológico , Embolia Pulmonar/epidemiologia , Tromboflebite/tratamento farmacológico , Tromboflebite/epidemiologia , Varfarina/uso terapêutico
11.
Addiction ; 88(9): 1195-203, 1993 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-8241919

RESUMO

Server intervention is a relatively new approach in the attempt to reduce the incidence of drinking and driving. Although a number of evaluations have suggested that the approach may be effective, there have been few comprehensive evaluations of such programmes. The present study utilized process evaluation techniques to assess reactions to a programme developed by the Addiction Research Foundation, and a quasi-experimental design to determine the impact of the programme on the serving practices of servers. Actors portrayed behaviours often faced by servers, and observers rated the reactions of the servers, who were unaware of the simulations, to these situations. The programme appears to have been effective in changing behaviour, in that trained servers exhibited less inappropriate responses than did untrained servers. In addition the results suggested that the programme increased servers' knowledge about their obligations and potential strategies for dealing with these situations. The implications of these findings for future implementations of such programmes are discussed.


Assuntos
Consumo de Bebidas Alcoólicas/prevenção & controle , Bebidas Alcoólicas/provisão & distribuição , Ocupações/legislação & jurisprudência , Comportamento Social , Acidentes de Trânsito/prevenção & controle , Consumo de Bebidas Alcoólicas/economia , Atitude , Condução de Veículo/legislação & jurisprudência , Canadá , Feminino , Promoção da Saúde , Humanos , Licenciamento , Masculino , Desenvolvimento de Programas
12.
Am J Clin Oncol ; 11(2): 126-30, 1988 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-3282423

RESUMO

Three cases of intraocular lymphoma are presented. One patient had only ocular involvement, one had involvement of the eye and central nervous system, and in the third patient, ocular lymphoma developed 1 year after the diagnosis of a systemic lymphoma. One patient died before treatment could be initiated, but the other two patients responded well to local radiotherapy. Only one patient who received radiation to both eyes and the whole brain, followed by systemic chemotherapy, remains alive 4 years after diagnosis. Eighty-seven cases of intraocular lymphoma reported in the literature are reviewed. Only 16.7% of cases involved the eyes alone without central nervous system or systemic disease. In more than one-half of the cases (59.7%), the eye was the primary site of involvement. Craniotomy or enucleation was required for diagnosis in 52.7% of patients, and diagnosis frequently followed a significant period of delay during which time patients were treated unsuccessfully for uveitis or iritis. Death for most patients was due to progressive central nervous system involvement. Therefore, we recommend combined modality therapy with radiation to the whole brain and both eyes, followed by systemic chemotherapy with or without intrathecal medications.


Assuntos
Neoplasias Oculares/radioterapia , Linfoma/radioterapia , Adulto , Idoso , Antineoplásicos/uso terapêutico , Terapia Combinada , Neoplasias Oculares/tratamento farmacológico , Neoplasias Oculares/fisiopatologia , Feminino , Humanos , Linfoma/tratamento farmacológico , Linfoma/fisiopatologia , Masculino
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...