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1.
J Strength Cond Res ; 31(5): 1177-1186, 2017 May.
Artigo em Inglês | MEDLINE | ID: mdl-27537411

RESUMO

Harris, NK, Dulson, DK, Logan, GRM, Warbrick, IB, Merien, FLR, and Lubans, DR. Acute responses to resistance and high-intensity interval training in early adolescents. J Strength Cond Res 31(5): 1177-1186, 2017-The purpose of this study was to compare the acute physiological responses within and between resistance training (RT) and high-intensity interval training (HIIT) matched for time and with comparable effort, in a school setting. Seventeen early adolescents (12.9 ± 0.3 years) performed both RT (2-5 repetitions perceived short of failure at the end of each set) and HIIT (90% of age-predicted maximum heart rate), equated for total work set and recovery period durations comprising of 12 "sets" of 30-second work followed by 30-second recovery (total session time 12 minutes). Variables of interest included oxygen consumption, set and session heart rate (HR), and rate of perceived exertion, and change in salivary cortisol (SC), salivary alpha amylase, and blood lactate (BL) from presession to postsession. Analyses were conducted to determine responses within and between the 2 different protocols. For both RT and HIIT, there were very large increases pretrial to posttrial for SC and BL, and only BL increased greater in HIIT (9.1 ± 2.6 mmol·L) than RT (6.8 ± 3.3 mmol·L). Mean set HR for both RT (170 ± 9.1 b·min) and HIIT (179 ± 5.6 b·min) was at least 85% of HRmax. V[Combining Dot Above]O2 over all 12 sets was greater for HIIT (33.8 ± 5.21 ml·kg·min) than RT (24.9 ± 3.23 ml·kg·min). Brief, repetitive, intermittent forays into high but not supramaximal intensity exercise using RT or HIIT seemed to be a potent physiological stimulus in adolescents.


Assuntos
Treinamento Intervalado de Alta Intensidade , Esforço Físico/fisiologia , Treinamento Resistido , Adolescente , Criança , Estudos Cross-Over , Feminino , Frequência Cardíaca , Humanos , Hidrocortisona/metabolismo , Ácido Láctico/sangue , Masculino , Consumo de Oxigênio , Distribuição Aleatória , Saliva/metabolismo , alfa-Amilases/metabolismo
2.
J Sports Sci ; 34(21): 2047-53, 2016 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-26890884

RESUMO

This study investigated the effects of epoch length and cut point selection on adolescent physical activity intensity quantification using vertical axis and vector magnitude (VM) measurement with the ActiGraph GT3X+ accelerometer. Four hundred and nine adolescents (211 males; 198 females) aged 12-16 years of age wore accelerometers during waking hours. The GT3X+ acceleration counts were reintegrated into 1, 5, 15, 30 and 60 s epoch lengths for both vertical axis and VM counts. One cut point was applied to vertical axis counts and three different cut points were applied to VM counts for each epoch length. Significant differences (P < 0.01) in mean total counts per day were observed between vertical axis and VM counts, and between epoch lengths for VM only. Differences in physical activity levels were observed between vertical and VM cut points, and between epoch lengths across all activity intensities. Our findings illustrate the magnitude of differences in physical activity outcomes that occur between axis measurement, cut points and epoch length. The magnitude of difference across epoch length must be considered in the interpretation of accelerometer data and seen as a confounding variable when comparing physical activity levels between studies.


Assuntos
Acelerometria/métodos , Exercício Físico , Actigrafia , Adolescente , Criança , Fatores de Confusão Epidemiológicos , Feminino , Humanos , Masculino , Monitorização Ambulatorial , Comportamento Sedentário , Estatística como Assunto
3.
New Phytol ; 205(2): 882-93, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-25329638

RESUMO

Anthocyanin pigments accumulate to form spatially restricted patterns in plants, particularly in flowers, but also occur in vegetative tissues. Spatially restricted anthocyanin leaf markings are poorly characterised in plants, but are common in forage legumes. We hypothesised that the molecular basis for anthocyanin leaf markings in Trifolium spp. is due to the activity of a family of R2R3-MYB genes. R2R3-MYB genes were identified that are associated with the two classic pigmentation loci in T. repens. The R locus patterns 'red leaf', 'red midrib' and 'red fleck' are conditioned by a single MYB gene, RED LEAF. The 'diffuse red leaf' trait is regulated by the RED LEAF DIFFUSE MYB gene. The V locus was identified through mapping two V-linked traits, 'V-broken yellow' (Vby) and 'red leaflet' (Vrl). Two highly similar R2R3-MYB genes, RED V-a and RED V-b, mapped to the V locus and co-segregated with the RED V pigmentation pattern. Functional characterisation of RED LEAF and RED V was performed, confirming their function as anthocyanin regulators and identifying a C-terminal region necessary for transactivation. The mechanisms responsible for generating anthocyanin leaf markings in T. repens provide a valuable system to compare with mechanisms that regulate complex floral pigmentation.


Assuntos
Antocianinas/genética , Folhas de Planta/fisiologia , Proteínas de Plantas/genética , Trifolium/genética , Trifolium/metabolismo , Antocianinas/metabolismo , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Regulação da Expressão Gênica de Plantas , Genes myb , Dados de Sequência Molecular , Família Multigênica , Filogenia , Pigmentação/genética , Folhas de Planta/metabolismo , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas , Nicotiana/genética
4.
Pain ; 164(6): 1222-1239, 2023 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-36729810

RESUMO

ABSTRACT: Central sensitization (CS) is defined as an increased nociceptive responsiveness due to sensitization of neurons in the central nervous system, usually the result of prolonged nociceptive input or a disease state associated with noxious inputs (eg, polyarthritis). The concept of CS has recently been adopted in clinical assessments of chronic pain, but its diagnosis in humans may now include a wide range of hypervigilant responses. The purpose of this review is to ascertain whether self-report questionnaires linked with CS are associated with enhanced nociceptive responses or whether they measure sensitivity in a broader sense (ie, emotional responses). According to our published, PROSPERO-registered review protocol (CRD42021208731), a predefined search of studies that involve the Central Sensitization Inventory (CSI) or Pain Sensitivity Questionnaire (PSQ), correlated with either nociceptive sensory tests or emotional hypervigilance was conducted on MEDLINE, PsycINFO, and Web of Science. Correlations between the CSI or PSQ with our primary outcomes were extracted and meta-analysed. A review of 66 studies totalling 13,284 participants found that the CSI (but not the PSQ) strongly correlated with psychological constructs: depression, anxiety, stress, pain catastrophising, sleep, and kinesiophobia. The CSI and PSQ showed weak or no correlations with experimental measures of nociceptive sensitivity: pain thresholds, temporal summation, or conditioned pain modulation. The PSQ did, however, correlate strongly with phasic heat and tonic cold pain tests. The studies reviewed did not provide sufficient evidence that self-report measures reflect a canonical understanding of CS. The CSI more closely reflects psychological hypervigilance than increased responsiveness of nociceptive neurons.


Assuntos
Dor Crônica , Nociceptividade , Humanos , Sensibilização do Sistema Nervoso Central/fisiologia , Dor Crônica/psicologia , Inquéritos e Questionários , Limiar da Dor
5.
J Intellect Disabil Res ; 55(11): 1009-19, 2011 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-21726316

RESUMO

BACKGROUND: Health checks for people with intellectual disabilities (ID) have been recommended as one component of health policy responses to the poorer health of people with ID. This review summarises evidence on the impact of health checks on the health and well-being of people with ID. METHODS: Electronic literature searches and email contacts were used to identify literature relevant to the impact of health checks for people with ID. RESULTS: A total of 38 publications were identified. These involved checking the health of over 5000 people with ID from a range of countries including a full range of people with ID. Health checks consistently led to detection of unmet health needs and targeted actions to address health needs. CONCLUSIONS: Health checks are effective in identifying previously unrecognised health needs, including life-threatening conditions. Future research should consider strategies for optimising the cost-effectiveness or efficiency of health checks.


Assuntos
Medicina Baseada em Evidências/normas , Necessidades e Demandas de Serviços de Saúde/normas , Deficiência Intelectual/terapia , Atenção Primária à Saúde/normas , Garantia da Qualidade dos Cuidados de Saúde/normas , Nível de Saúde , Humanos
6.
Pain Rep ; 6(4): e962, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34712886

RESUMO

INTRODUCTION: Central sensitization (CS) was first defined in animal studies to be increased nociceptive responsiveness due to sensitization of neurons in the central nervous system, usually the result of prolonged nociceptive input or a disease state. Recently, the concept of CS has been adopted in clinical assessments of chronic pain, but its diagnosis in humans has expanded to include the enhancement of a wide range of nociceptive, sensory, and emotional responses. Many poorly understood pain disorders are referred to as "central sensitivity syndrome," a term associated with a broad range of hypervigilant sensory and emotional responses. Diagnosis often involves a review of medical records and an assessment of behaviour, emotional disposition, and overall sensitivity of a patient. Obviously, these assessments are unable to directly capture the responsiveness of nociceptive neurons. The purpose of this review is to ascertain whether self-report questionnaires associated with central sensitization and the diagnosis of central sensitivity syndrome are associated with enhanced nociceptive responses or whether they more validly measure sensitivity in a broader sense (ie, including emotional responses). METHODS: Following the PRISMA guidelines, a detailed search of studies that involve the Central Sensitization Inventory or Pain Sensitivity Questionnaire correlated with either nociceptive sensory tests (quantitative sensory testing) or emotional hypervigilance (anxiety, depression, stress, etc) will be conducted on MEDLINE, PsychINFO, and Web of Science. PERSPECTIVE: The review is expected to synthesize correlations between sensitivity questionnaires and nociceptive or emotional sensitivity to determine whether these questionnaires reflect a broadened understanding of the term "central sensitization."

7.
Cancer Res ; 49(13): 3656-61, 1989 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-2659166

RESUMO

In an attempt to generate antibodies which recognize novel tumor-associated antigens we have immunized Rhesus monkeys (Macaca mulatta) with human colon carcinoma cells prepared from freshly excised tumors. Immunohistochemical characterization of polyclonal antisera from one monkey (DF6) revealed preferential reactivity with primary and metastatic colon carcinoma tissue, and a general lack of recognition of nonneoplastic mucosa. Immunoreactivity was localized to the luminal contents of glandular structures and to the apical surfaces of cells lining these glands. Immunoreactivity was not observed with any normal tissue examined. Examination of neoplastic tissues revealed reactivity with two gastric carcinoma specimens (n = 2) and one breast carcinoma (n = 7). In reactive colon carcinoma tissues, the pattern of staining with DF6 was similar to that of several other antibodies including anti-carcinoembryonic antigen, B72.3, anti-Le(x) and anti-Le(y). However, the panel of tissues recognized by these antibodies and DF6 differed significantly, suggesting that the DF6-reactive epitopes are unique. Human colon carcinoma cell lines maintained in vitro also expressed antigens recognized by DF6 in a pattern similar to that of surgically excised tissue. This preliminary characterization of DF6 antiserum suggests that immunization of Rhesus monkeys is a potentially useful protocol for identifying antigens preferentially expressed by human colon carcinoma.


Assuntos
Anticorpos Antineoplásicos/imunologia , Antígenos de Neoplasias/imunologia , Carcinoma/imunologia , Neoplasias do Colo/imunologia , Animais , Antígeno Carcinoembrionário/imunologia , Reações Cruzadas , Imunofluorescência , Humanos , Macaca mulatta , Células Tumorais Cultivadas/imunologia
8.
Cancer Res ; 43(12 Pt 1): 6057-65, 1983 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-6640547

RESUMO

The polypeptide and phosphoprotein profiles of a spectrum of B16 melanoma clones of defined metastatic potential have been analyzed by two-dimensional gel electrophoresis. To accommodate the documented instability of metastatic properties in B16 clones, in vitro biochemical assays were always accompanied by in vivo assays of the metastatic behavior using replicate samples of the same clonal populations harvested on the same day. To exclude differences in polypeptide and phosphoprotein profiles resulting from inherent variation in electrophoretic measurements made at different times, polypeptides and phosphoproteins were analyzed in unison for every clone, and a series of clones was examined in parallel in each experiment. Also, samples were electrophoresed simultaneously using a custom-designed apparatus capable of accommodating 20 two-dimensional samples. When tested under these stringent conditions, the polypeptide profiles of B16 clones were indistinguishable. Significant qualitative and quantitative differences in phosphoprotein expression were detected in each clone, but no correlations were found between alterations in protein phosphorylation and metastatic potential. Over 200 discrete phosphoproteins were detected in each clone, but interclonal variation was confined to approximately 10 to 15 phosphoproteins. Expression of three phosphoproteins with the following molecular weights (in kilodaltons) and isoelectric points was strictly qualitative: pp96 (7.9); pp30 (8.2); and pp30 (8.8). In any given clone, they were present individually at equal intensities or were completely absent, but their expression was not coordinate. The data indicate that expression of polypeptide gene products is similar in B16 melanoma clones with widely differing metastatic abilities, but considerable clonal variability exists in posttranslational covalent modification of cell proteins. The possible contribution of protein phosphorylation and other posttranslational pathways in generating the extensive phenotypic heterogeneity observed in tumor cell subpopulations within the same tumor and in the rapid generation of new clonal variants with altered metastatic properties are discussed.


Assuntos
Variação Genética , Melanoma/metabolismo , Proteínas de Neoplasias/metabolismo , Animais , Linhagem Celular , Células Clonais , Eletroforese em Gel de Poliacrilamida , Melanoma/genética , Camundongos , Camundongos Endogâmicos C57BL , Metástase Neoplásica , Proteínas de Neoplasias/genética , Fosfoproteínas/isolamento & purificação , Fosforilação
9.
Cancer Res ; 45(12 Pt 1): 6124-30, 1985 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-2415238

RESUMO

The role of DNA methylation in the expression of the metastatic phenotype in B16 murine melanoma cells in syngeneic C57BL/6 mice has been investigated. B16 cultures were incubated in vitro for either 6 or 18 h with the DNA hypomethylating agents, 5-azacytidine (5-Aza-CR) or 5-fluoro-2'-deoxycytidine (FCdR). At various times (1-13 days) following treatment, tumor cells were tested for their ability to form metastatic deposits when injected at different doses either i.v. (experimental metastasis) or s.c. in the footpad (spontaneous metastasis). Both 5-Aza-CR (0.5-15 microM) and FCdR (0.3-30 microM) caused a dose-dependent increase in the ability of B16 cells to form experimental pulmonary metastases. Increased capacity to form experimental pulmonary metastases was evident 24 h following treatment with 5-Aza-CR and 13 days following treatment with FCdR. The enhanced metastatic burden involved both an increase in the median number of lung colonies and a substantial increase in the size of individual lesions. 5-Aza-CR or FCdR treatment of B16 cell populations did not influence either the tumorigenicity or their ability to form spontaneous metastases. Parallel in vitro experiments using high-performance liquid chromatography analysis of cellular DNA demonstrated that under conditions in which 5-Aza-CR and FCdR enhanced formation of experimental metastases by B16 cells, there were readily detectable alterations in the 5-methylcytosine levels in DNA extracted from drug-treated cultures. These data suggest that drug-induced alterations in DNA methylation can affect biochemical pathway(s) whose expression is associated with the successful organ colonization by circulating tumor cells.


Assuntos
Azacitidina/farmacologia , DNA de Neoplasias/metabolismo , Melanoma/patologia , Animais , Desoxicitidina/análogos & derivados , Desoxicitidina/farmacologia , Feminino , Neoplasias Pulmonares/secundário , Melanoma/genética , Metilação , Camundongos , Camundongos Endogâmicos C57BL , Metástase Neoplásica
10.
Cancer Res ; 47(11): 2804-8, 1987 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-2436758

RESUMO

The requirements for interferon (IFN)-induced priming of murine peritoneal macrophages for cytolysis of tumor cell lines of distinct histological origin were investigated. Lysis of B16 melanoma targets required exposure of elicited macrophages to recombinant murine gamma interferon plus lipopolysaccharide (LPS) together, while sequential treatment of macrophages with IFN-gamma then LPS resulted in lysis of P815 mastocytoma targets. The kinetics of macrophage activation by IFN-gamma and LPS for lysis of P815 and B16 melanoma targets varied considerably, 8 h being sufficient for P815 targets but 24 h being required for B16 targets. Pretreatment of the macrophages with the antibiotic polymyxin B was able to inhibit completely the induction of tumor lysis of B16 targets but not of P815 targets. In addition, IFN-alpha/beta was able to prime macrophages for lysis of P815 targets but not of B16. Finally, the kinetics of priming macrophages with IFN-gamma for lysis of B16 targets had a profound effect on the subsequent exposure time requirement for LPS. The results indicate that the induction of murine macrophage-mediated tumor cytotoxicity can vary considerably depending on the amount and type of interferon used, the presence of a second signal, and the type of tumor target used.


Assuntos
Interferons/farmacologia , Ativação de Macrófagos/efeitos dos fármacos , Macrófagos/imunologia , Animais , Sangue , Células Cultivadas , Meios de Cultura , Citotoxicidade Imunológica , Imunidade Celular , Lipopolissacarídeos/farmacologia , Camundongos , Neoplasias Experimentais/imunologia , Polimixina B/farmacologia , Fatores de Tempo
11.
Cancer Res ; 49(11): 2898-904, 1989 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-2541895

RESUMO

Conditioned media collected under serum-free conditions over 24 to 48 h from 18 human colon adenocarcinoma cell lines were analyzed for transforming growth factor, types alpha and beta (TGF-alpha and -beta), and platelet-derived growth factor in assays for anchorage-independent growth and radioreceptor competition. Detectable levels of TGF-alpha, TGF-beta, and platelet-derived growth factor were produced by 17, 16, and 6 cell lines, respectively. Three liters of conditioned medium from highly tumorigenic (HT-29, DLD-1, and SW620) and nontumorigenic (SKCO-1) colon cell lines and from nonneoplastic rat kidney (NRK-52E) and small intestinal (IEC-6) epithelial cells were purified by high-performance liquid chromatography and assayed for TGF-alpha- and TGF-beta-like activity. The highly tumorigenic colon cell lines produced 10- to 45-fold (soft agar), 19- to 90-fold (radioreceptor), and 4- to 35-fold (radioimmunoassay) more TGF-alpha activity compared to the nonneoplastic rat intestinal (IEC) epithelial cells. NRK-52E did not produce detectable TGF-alpha activity. Radioimmunoassay analysis of peak fractions revealed only TGF-alpha immunoreactivity; epidermal growth factor was not detected. Levels of TGF-beta-like material in the colon carcinoma populations were comparable (HT-29) or elevated (DLD-1, SW620) only 3- to 4-fold (soft agar) or 1- to 3-fold (radioreceptor binding) compared to IEC cells or NRK-52E. Growth factor production is an ubiquitous property of colon carcinoma cell lines maintained in vitro and is consistent with this class of molecule, playing a contributory role in regulating cell growth.


Assuntos
Neoplasias do Colo/metabolismo , Neoplasias Colorretais/metabolismo , Receptores ErbB/biossíntese , Fator de Crescimento Derivado de Plaquetas/biossíntese , Receptores de Superfície Celular/biossíntese , Fatores de Crescimento Transformadores/biossíntese , Animais , Cromatografia Líquida de Alta Pressão , Meios de Cultura/análise , Relação Dose-Resposta a Droga , Humanos , Ratos , Receptores de Fatores de Crescimento Transformadores beta , Células Tumorais Cultivadas/metabolismo
12.
Biochim Biophys Acta ; 641(2): 410-5, 1981 Mar 06.
Artigo em Inglês | MEDLINE | ID: mdl-7213726

RESUMO

Using the output of a rotational viscometer as a continuous index of aggregation, we have shown previously that the concanavalin A agglutination of native human erythrocytes can be resolved into three distinct classes of aggregation, static, type I and type II. Static aggregation occurs in the absence of shear forces while both type I and II aggregations are shear-induced. We now report that the increased concanavalin A agglutination of trypsinised erythrocytes is attributable to a specific enhancement in the development of type II aggregation. While type II formation in native cell suspensions requires high concanavalin A concentrations and continual shearing, an indistinguishable type of aggregation develops in suspensions of trypsinised red cells at considerably lower lectin concentrations and in the absence of applied shear forces.


Assuntos
Concanavalina A/farmacologia , Agregação Eritrocítica , Eritrócitos/metabolismo , Humanos , Tripsina/metabolismo
13.
Biochim Biophys Acta ; 717(1): 175-8, 1982 Jul 16.
Artigo em Inglês | MEDLINE | ID: mdl-7104387

RESUMO

A high performance liquid chromatography system is described which provides a rapid and convenient assay for the relative amounts of intact (26000 dalton) and fragmented (14000 and 12000 dalton) subunits present in preparations of concanavalin A. Analyses were performed on an HPLC size exclusion column using either 8M urea or 6M guanidine hydrochloride as denaturing eluents. The efficiency and resolving power of this technique were confirmed by sodium dodecyl sulfate polyacrylamide gel electrophoresis. This HPLC assay facilitated the monitoring of the purification of concanavalin A to prepare a homogeneous preparation necessary for its biological evaluation.


Assuntos
Concanavalina A/isolamento & purificação , Cromatografia Líquida de Alta Pressão/métodos , Eletroforese em Gel de Poliacrilamida , Substâncias Macromoleculares , Peso Molecular
14.
J Bone Miner Res ; 8(2): 239-47, 1993 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-7680185

RESUMO

This study details the investigation of induction of retractile shape change in the osteoclast through inhibition of adhesion between osteoclasts and matrix with (1) peptide analogs bearing an Arg-Gly-Asp (RGD) sequence, (2) antibodies to the integrin alpha V beta 3 vitronectin receptor, and (3) the RGD-containing snake venom peptide echistatin. Osteoclast retraction on dentin has been demonstrated for GRGDSP peptide, in contrast to the inactivity of the analog containing the conservative RGE sequence modification. An osteoclast adhesion assay employing rat or chick bone cells and serum-coated glass coverslips as substrate was developed for routine evaluation of inhibition of adhesion. Antibodies F4 and F11 to the beta 3 chain of rat vitronectin receptor were effective at submicromolar concentrations in rat osteoclasts (IC50 0.29 and 0.05 microM, respectively), whereas MAb 23C6 to human/chick vitronectin receptor was somewhat less effective against chick osteoclasts (IC50 1.6 microM). A rank order of RGD analog activity (mean IC50, microM) in the serum-coated glass adhesion assay was derived for the linear peptides GRGDSP (201 microM), GRGDTP (180 microM), Ac-RGDS-NH2 (84 microM), Ac-RGDV-NH2 (68 microM), RGDV (43 microM), GRGDS (38 microM), and RGDS (26 microM). The two most potent short peptides were the cyclic analog SK&F 106760 Ac-S,S-cyclo-(Cys-(N alpha Me)Arg-Gly-Asp-Pen)-NH2 (IC50 7.0 microM), and the Telios peptide H-Gly-S,S-cyclo-(Pen-Gly-Arg-Gly-Asp-Ser-Pro-Cys)-Ala-OH (IC50 6.6 microM). The snake venom peptide echistatin was the most potent substance evaluated in the serum-coated glass assay (IC50 0.78 nM) employing either rat or chick osteoclasts.(ABSTRACT TRUNCATED AT 250 WORDS)


Assuntos
Oligopeptídeos/farmacologia , Osteoclastos/efeitos dos fármacos , Peptídeos , Receptores de Citoadesina/fisiologia , Venenos de Víboras/farmacologia , Sequência de Aminoácidos , Animais , Osso e Ossos , Adesão Celular/efeitos dos fármacos , Embrião de Galinha , Dentina , Vidro , Peptídeos e Proteínas de Sinalização Intercelular , Dados de Sequência Molecular , Osteoclastos/química , Osteoclastos/fisiologia , Peptídeos Cíclicos/farmacologia , Ratos , Receptores de Citoadesina/imunologia , Receptores de Vitronectina , Relação Estrutura-Atividade
15.
Clin Exp Metastasis ; 6(3): 185-200, 1988.
Artigo em Inglês | MEDLINE | ID: mdl-2450714

RESUMO

The role of DNA methylation in the generation of tumor cell variants with altered growth behavior has been investigated. Cultures of the clonally heterogeneous B16 melanoma cell line and a clonal population (B16-CL) derived from it were treated with the DNA hypomethylating agent, 5-azacytidine (5-Aza-CR). The tumorigenic and metastatic properties of (sub)clones isolated from these cultures before and after drug treatment were assayed by injection via multiple routes into syngeneic C57BL/6 mice using a range of cell doses. The rate of tumor growth was monitored following intrafootpad (i.f.p.) injection and the tumor incidence was calculated from the frequency of tumor formation at i.f.p. and supraclavicular subcutaneous (s.c.) sites. Formation of both spontaneous (i.f.p., s.c. inoculations) and experimental (intravenous (i.v.) inoculation) metastatic potential was also investigated. The most consistent effect of 5-Aza-CR was the introduction of heterogeneity with respect to the tumorigenic phenotype. The effect of 5-Aza-CR treatment on metastatic behavior was variable. The majority of tumor cell variants that arose following 5-Aza-CR treatment displayed decreased malignant potential and reduced DNA methylation levels relative to untreated control cells, but the correlation was not absolute. The decreases in DNA methylation levels induced by 5-Aza-CR were unstable and began to rebound within 1 week of drug treatment. The results of the current study indicate that although 5-Aza-CR can introduce significant shifts in the malignant properties of treated cells, the direction and magnitude of the induced alterations are not predictable and are influenced by a variety of experimental parameters including the starting tumor cell population, route of tumor cell inoculation, and the drug treatment protocol. In addition, because DNA methylation levels can rebound rapidly (days) it is difficult to correlate changes in this parameter with the observed alterations in malignancy, which can only be assessed in long-term biological assays (weeks).


Assuntos
Azacitidina/farmacologia , DNA de Neoplasias/metabolismo , Melanoma/patologia , Animais , Linhagem Celular/efeitos dos fármacos , Cromatografia Líquida de Alta Pressão , DNA de Neoplasias/efeitos dos fármacos , Feminino , Neoplasias Pulmonares/secundário , Metilação , Camundongos , Camundongos Endogâmicos C57BL , Transplante de Neoplasias , Ensaio Tumoral de Célula-Tronco
16.
J Med Chem ; 31(9): 1762-7, 1988 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-2970550

RESUMO

The synthesis and testing of potential multisubstrate inhibitors of tyrosine-specific protein kinases are described. One of the substrates, ATP, was mimicked by the known kinase inhibitor 5'-[4-(fluorosulfonyl)benzoyl]adenosine, which was covalently linked via the sulfonyl moiety to tyrosine mimics. The resulting multisubstrate inhibitors were tested for their ability to inhibit the transfer of phosphate from ATP to a protein acceptor by p60v-abl, the tyrosine kinase encoded by the transforming gene (v-abl) of the Abelson murine leukemia virus (A-MuLV). Although the series of inhibitors displayed moderately potent activity (IC50 values as low as 19 microM), the absence of large effects produced by modification of the tyrosine mimic suggests that they do not behave as multisubstrate inhibitors but bind primarily through the adenosine moiety common to all the inhibitors. This interpretation is strengthened by the finding that the inhibitors lack specificity, inhibiting a serine kinase at comparable concentrations.


Assuntos
Adenosina/análogos & derivados , Oncogenes , Proteínas Tirosina Quinases/antagonistas & inibidores , Vírus da Leucemia Murina de Abelson/enzimologia , Vírus da Leucemia Murina de Abelson/genética , Adenosina/farmacologia , Trifosfato de Adenosina/metabolismo , Sítios de Ligação , Fenômenos Químicos , Química , Escherichia coli/enzimologia , Escherichia coli/genética , Cinética , Fosforilação , Inibidores de Proteínas Quinases , Proteínas Serina-Treonina Quinases , Proteínas Tirosina Quinases/genética , Proteínas Tirosina Quinases/metabolismo , Proteínas Recombinantes/antagonistas & inibidores , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Tirosina/metabolismo
17.
J Med Chem ; 31(9): 1768-72, 1988 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-3045321

RESUMO

Tyrosine-specific protein kinases that transfer the terminal phosphate from ATP to protein acceptors are associated with certain transforming viruses and cell surface growth factor receptors. Here we describe the synthesis and testing of potential multisubstrate inhibitors of this class of enzymes. The inhibitors were prepared by covalent attachment of the terminal phosphate of ATP or its tetraphosphate analogue to tyrosine mimics. Testing against p60v-abl, the tyrosine kinase from the Abelson murine leukemia virus, showed that the series of inhibitors was moderately potent (IC50 values as low as 13 microM). However, structural modification of the tyrosine mimic, including replacement with a serine-like moiety, had little effect on potency. It is therefore concluded that the ATP moiety is largely responsible for binding and that the enzyme requires additional structural features for recognition of the tyrosine-containing substrate.


Assuntos
Trifosfato de Adenosina/análogos & derivados , Oncogenes , Proteínas Tirosina Quinases/antagonistas & inibidores , Tirosina/análogos & derivados , Vírus da Leucemia Murina de Abelson/enzimologia , Vírus da Leucemia Murina de Abelson/genética , Trifosfato de Adenosina/metabolismo , Amidas/síntese química , Amidas/farmacologia , Fenômenos Químicos , Química , Escherichia coli/enzimologia , Escherichia coli/genética , Cinética , Ácidos Fosfóricos/síntese química , Ácidos Fosfóricos/farmacologia , Fosforilação , Proteínas Tirosina Quinases/genética , Proteínas Tirosina Quinases/metabolismo , Proteínas Recombinantes/antagonistas & inibidores , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Relação Estrutura-Atividade , Tirosina/metabolismo
18.
AIDS Res Hum Retroviruses ; 9(1): 23-32, 1993 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-8094000

RESUMO

Our goal has been to develop a safe and effective system that would allow us to explore the functions of the human immunodeficiency virus (HIV) envelope. We have generated a human lymphoid cell line (TF228.1.16) that stably expresses functional HIV envelope proteins on its cell surface, and therefore closely mimics the viral envelope and virus-infected cells. The TF228.1.16 line forms syncytia with human cells of the CD4+ phenotype and provides a facile virus-free cell-based assay for examining the mechanism of syncytia formation and for evaluating novel agents that may disrupt this process. The TF228.1.16 cells also provide an opportunity to present the HIV envelope proteins to the immune system in cellular form. In vitro immunization of human peripheral blood mononuclear cells (PBMC) and in vivo immunization of rhesus monkeys with this reagent results in the production of antibodies with neutralizing (anti-syncytia) activities. When the HIV envelope is expressed against the background of human lymphoid cells, it may exhibit immune protection with unique properties that have not yet been explored. Our results indicate that a virus-free cell system can play an important role in exploring the biology and function of HIV-envelope proteins without the interference of other viral components present in infected cells. This paper discusses these results, and examines the potential use of TF228.1.16 as a vaccine.


Assuntos
Produtos do Gene env/fisiologia , Anticorpos Anti-HIV/biossíntese , HIV-1 , Precursores de Proteínas/fisiologia , Células Tumorais Cultivadas , Animais , Especificidade de Anticorpos , Linfócitos T CD4-Positivos/fisiologia , Produtos do Gene env/genética , Produtos do Gene env/imunologia , Células Gigantes , Proteína gp120 do Envelope de HIV/análise , Proteína gp120 do Envelope de HIV/imunologia , Proteína gp160 do Envelope de HIV , Proteína gp41 do Envelope de HIV/análise , HIV-1/imunologia , Humanos , Imunização , Macaca mulatta , Precursores de Proteínas/genética , Precursores de Proteínas/imunologia , Transfecção , Células Tumorais Cultivadas/imunologia
19.
Biochem Pharmacol ; 37(21): 4089-93, 1988 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-3190747

RESUMO

Challenge of human cells with auranofin, 2,3,4,6-tetra-O-acetyl-1-thio-beta-D-glucopyranosato-S-triethylpho sphine gold(I) (Ridaura), a gold-containing compound approved by the FDA for the treatment of rheumatoid arthritis, induces the specific synthesis of a 32-kD stress protein (p32) [Caltabiano et al., Biochem. biophys. Res. Commun. 138, 1074 (1986)]. To establish a structure-activity relationship for this effect, a series of auranofin ligands, gold analogs, and other anti-arthritic agents were examined for their abilities to stimulate p32 synthesis. The results indicate that the gold atom is necessary for enhanced expression of p32. However, the structure of co-ordinated ligands also affected potency, and gold complexes bearing several phosphine or thiosugar groups exhibited the greatest activity. These data indicate that the distinct potencies of auranofin analogs probably reflect their membrane permeability and subsequent delivery of pharmacologically active concentrations of gold to the cytoplasmic compartment.


Assuntos
Auranofina/farmacologia , Proteínas de Choque Térmico/biossíntese , Artrite/tratamento farmacológico , Eletroforese em Gel de Poliacrilamida , Humanos , Técnicas In Vitro , Solubilidade , Relação Estrutura-Atividade , Fatores de Tempo , Células Tumorais Cultivadas
20.
Invest Radiol ; 23(9): 677-9, 1988 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-3182215

RESUMO

To evaluate the potential of 9.4 T imaging in distinguishing normal and neoplastic tissues, we examined the progressive growth of human colon and prostate adenocarcinoma xenografts in nude mice. Images were obtained with a resolution of 100 X 100 X 650 micron, and tumors were clearly distinguished from normal tissue with high contrast. These results demonstrate the feasibility of detecting small human tumors in live nude mice with microscopic resolution at 9.4 T.


Assuntos
Adenocarcinoma/diagnóstico , Neoplasias do Colo/diagnóstico , Imageamento por Ressonância Magnética , Neoplasias da Próstata/diagnóstico , Animais , Feminino , Humanos , Masculino , Camundongos , Camundongos Nus , Transplante de Neoplasias , Transplante Heterólogo
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