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1.
Appetite ; 87: 365-70, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25596500

RESUMO

The goals of this study were to determine if a change in certain motives to eat highly palatable food, as measured by the Palatable Eating Motives Scale (PEMS), could predict a change in body mass index (BMI) over time, to assess the temporal stability of these motive scores, and to test the reliability of previously reported associations between eating tasty foods to cope and BMI. BMI, demographics, and scores on the PEMS and the Binge Eating Scale were obtained from 192 college students. Test-retest analysis was performed on the PEMS motives in groups varying in three gap times between tests. Regression analyses determined what PEMS motives predicted a change in BMI over two years. The results replicated previous findings that eating palatable food for Coping motives (e.g., to forget about problems, reduce negative feelings) is associated with BMI. Test-retest correlations revealed that motive scores, while somewhat stable, can change over time. Importantly, among overweight participants, a change in Coping scores predicted a change in BMI over 2 years, such that a 1-point change in Coping predicted a 1.76 change in BMI (equivalent to a 10.5 lb. change in body weight) independent of age, sex, ethnicity, and initial binge-eating status (Cohen's f(2) effect size = 1.44). The large range in change of Coping scores suggests it is possible to decrease frequency of eating to cope by more than 1 scale point to achieve weight losses greater than 10 lbs. in young overweight adults, a group already at risk for rapid weight gain. Hence, treatments aimed specifically at reducing palatable food intake for coping reasons vs. for social, reward, or conformity reasons, should help achieve a healthier body weight and prevent obesity if this motive-type is identified prior to significant weight gain.


Assuntos
Adaptação Psicológica , Índice de Massa Corporal , Ingestão de Alimentos/psicologia , Adolescente , Adulto , Peso Corporal , Bulimia/psicologia , Estudos Transversais , Emoções , Comportamento Alimentar/psicologia , Feminino , Humanos , Modelos Lineares , Estudos Longitudinais , Masculino , Motivação , Obesidade/psicologia , Sobrepeso/psicologia , Reprodutibilidade dos Testes , Fatores de Risco , Autorrelato , Estudantes , Adulto Jovem
2.
Eur J Cancer Care (Engl) ; 22(3): 389-99, 2013 May.
Artigo em Inglês | MEDLINE | ID: mdl-23350656

RESUMO

In accepting illness as a subjective experience, there is value in examining how individuals perceive, interpret and understand its challenges, knowledge critical to understanding patterns of response. Although researchers have considered how prostate cancer can challenge 'embodied masculinities' few studies have considered gendered dynamics in men's cancer experiences more broadly. This article helps attends to this gap by examining how men with a variety of cancers made sense of the challenges of their illness. The results, part of a grounded theory study including 30 Canadian adult men, highlight how the men perceived a troubled future and a discordant present, a profound sense of uncertainty, and feelings of isolation. These patterns, infused with societal expectations for male bodies and lives, move beyond the particular needs varying by medical, demographic and situational diversities. More specifically, they are recognised as consistent with a 'biographical disruption' or an ongoing problematic situation destabilising how the men made sense of their individual selves and the world around them. Focused on commonalities and considerate of diversities, findings are reviewed in relation to existing work on illness and gender identity and work specific to men with cancer. Implications are discussed.


Assuntos
Adaptação Psicológica , Neoplasias/psicologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Imagem Corporal/psicologia , Canadá , Humanos , Masculino , Pessoa de Meia-Idade , Autoimagem , Isolamento Social/psicologia
3.
Connect Tissue Res ; 42(1): 1-12, 2001.
Artigo em Inglês | MEDLINE | ID: mdl-11696984

RESUMO

Although matrix metalloproteinase-8 (MMP-8) was regarded as the exclusive product of the neutrophils, recent studies have shown that it is also expressed in articular chondrocytes, rheumatoid synovial fibroblasts and endothelial cells. Our aim was to determine the expression of MMP-8 in human fibroblasts (HF) by reverse transcription/polymerase chain reaction (RT/PCR). Northern and Western blotting methods and MMP-8 activity assay. We have shown the expression of MMP-8 in HF and its dose-dependent upregulation by basic calcium phosphate (BCP) and calcium pyrophosphate dihydrate (CPPD) crystals which are markers of severe joint degeneration in osteoarthritis. These effects require new protein synthesis and are reversed by phosphocitrate (PC). The results also show that this fibroblast MMP-8 is distinct from the neutrophil MMP-8 and from the fibroblast MMP-1. These results indicate that MMP-8 may play a significant role in the pathogenic effects of the crystals in osteoarthritis.


Assuntos
Fosfatos de Cálcio/farmacologia , Pirofosfato de Cálcio/farmacologia , Citratos/farmacologia , Fibroblastos/enzimologia , Metaloproteinase 8 da Matriz/biossíntese , Antibacterianos/farmacologia , Northern Blotting/métodos , Western Blotting/métodos , Células Cultivadas , Colagenases/genética , Cristalização , Cicloeximida/farmacologia , Relação Dose-Resposta a Droga , Doxiciclina/farmacologia , Indução Enzimática , Fibroblastos/citologia , Fibroblastos/efeitos dos fármacos , Humanos , Metaloproteinase 1 da Matriz/genética , Metaloproteinase 13 da Matriz , Metaloproteinase 8 da Matriz/genética , Metaloproteinase 8 da Matriz/metabolismo , Inibidores da Síntese de Proteínas , Regulação para Cima
4.
Tob Control ; 10(3): 279-84, 2001 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-11544394

RESUMO

OBJECTIVE: To assess the content of two cigar "lifestyle" magazines, Cigar Aficionado and Smoke. DESIGN: Content analysis of cigar focused articles. SUBJECTS: Cigar focused articles (n = 353) from Cigar Aficionado and Smoke magazines. MAIN OUTCOME MEASURES: Primary focus; mention of health effects, environmental tobacco smoke, or scientific research; quotation and description of individuals; characteristics such as sex, age, ethnicity, smoking status, affiliation, and stance towards cigars; and overall image of cigars. RESULTS: Cigar business-focused articles were the largest category (40%, n = 143), followed by articles about cigar events (12%, n = 42). Notable were articles featuring cigar benefits to raise money for health charities. Celebrities were featured in 34% (n = 121) of articles and 96% (n = 271) favoured cigar use. Only four (1%) articles featured health effects of cigars as a primary focus. CONCLUSIONS: Cigar Aficionado and Smoke broke new ground in tobacco marketing by combining promotion of product, lifestyle, and industry in the same vehicle and linking the medium directly to product related events that extended its reach. The creation and marketing of new tobacco use sites challenges the increasing "isolation" of smokers, and positions cigar use as a socially welcome relief from restrictions. Public health advocates should anticipate and challenge other new tobacco marketing vehicles as communications technologies advance and public spaces for smoking shrink.


Assuntos
Estilo de Vida , Publicações Periódicas como Assunto/tendências , Indústria do Tabaco/tendências , Publicidade , Feminino , Comportamentos Relacionados com a Saúde , Humanos , Masculino , Relações Públicas , Tabagismo/psicologia
5.
Inorg Chem ; 40(7): 1614-25, 2001 Mar 26.
Artigo em Inglês | MEDLINE | ID: mdl-11261972

RESUMO

The syntheses and donor-acceptor properties of some novel, halo-bridged dicopper(II) complexes of alpha,alpha'-bis(5,7-dimethyl-1,4,8,11-tetraazacyclotetradecane-6-yl)-o-xylene are reported. These complexes were characterized by their magnetic and electrochemical behavior, X-ray structure analysis, FAB mass spectroscopy, and electronic spectra. The bromo-bridged complex crystallized in the tetragonal system, space group P4(3)2(1)2, with a = 12.6584(5) A, c = 28.6483 (14) A, Z = 4, R = 0.071, and Rw = 0.147. The chloro-bridged complex crystallized in the monoclinic system, space group C2/c, with a = 32.749(2) A, b = 18.8915(9) A, c = 26.022(2) A, beta =114.831 degrees, Z = 12, R = 0.080, and Rw = 0.132. Both molecules have C2 symmetry. The two copper(II) ions are axially bridged by a bromine or a chlorine, and the two macrocycles are bridged by an o-xylene group. Each complex displays a cofacial ring arrangement. The Cu-X distance (where X = Cl, Br) is shorter than the sum of van der Waals radii of Cu and X. The phenyl ring is approximately orthogonal to the Cu-X-Cu axis. The nonhalo-bridged complex has a significant affinity for halides (Kf approximately 10(4) M(-1)). The chloride-bridged complex had barely resolved differential pulse polarographic waves (DeltaE1/2 approximately 28 mV), while the bromide-bridged complex exhibited two CV waves in the 1.0-1.5 V range (DeltaE1/2 = 0.24 V). All the Cu(II)/Cu(I) couples were irreversible with a cathodic peak at about - 0.9 V. The magnetic susceptibility results below 20 K follow Curie-Weiss behavior, indicating that the magnetic interaction between the two Cu centers is weakly antiferromagnetic with J < or = -1 cm(-1) for all three complexes. A bridging-ligand-mediated superexchange model is used to treat the magnetic and electron-transfer coupling in the Cu(II)(X-)Cu(II) complexes. A single set of perturbation theory parameters is consistent with the magnetic and electrochemical observations on the chloride-bridged complex and the magnetic properties of the bromide-bridged complex. The electrochemical behavior of the latter suggests a relatively low-energy, high-spin configuration for the Cu(III)(Br-)Cu(II) complex. The analysis attributes the weak Cu(II)/Cu(II) coupling to the orthogonality of the donor and acceptor orbitals to the bridging axis. It is inferred that bridging halide-mediated metal-metal dsigma/psigma coupling significantly alters the chemical properties of the bimetallic complexes only when the donor and acceptor orbitals are coaxial with the bridging ligand. In such a limit, the coupling takes the form of a three-center bonding contribution.

6.
Am J Public Health ; 91(2): 288-91, 2001 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-11211641

RESUMO

OBJECTIVES: The purpose of this study was to examine print media coverage of cigars during the period 1987 to 1997. METHODS: A content analysis of 790 cigar-focused newspaper and magazine articles was conducted. RESULTS: Cigar-focused articles increased substantially over the study period, paralleling increased cigar consumption. Articles focused on cigar business (39%) and events (19%). Only 4% of articles focused on health effects. Sixty-two percent portrayed cigars favorably. The tobacco industry was mentioned in 54% of articles and portrayed positively in 78%. Forty-two percent of the individuals quoted or described in articles were affiliated with the tobacco industry; only 5% were government/public health figures. CONCLUSIONS: Print coverage of cigars failed to communicate health risk messages and contributed to positive images of cigars.


Assuntos
Publicidade/estatística & dados numéricos , Publicidade/tendências , Meios de Comunicação de Massa/estatística & dados numéricos , Meios de Comunicação de Massa/tendências , Jornais como Assunto/estatística & dados numéricos , Jornais como Assunto/tendências , Nicotiana , Publicações Periódicas como Assunto/estatística & dados numéricos , Publicações Periódicas como Assunto/tendências , Plantas Tóxicas , Fumar/psicologia , Atitude Frente a Saúde , Conhecimentos, Atitudes e Prática em Saúde , Humanos , Fumar/efeitos adversos , Comportamento Social , Percepção Social , Indústria do Tabaco/estatística & dados numéricos , Indústria do Tabaco/tendências , Estados Unidos
7.
J Biol Chem ; 275(15): 11327-32, 2000 Apr 14.
Artigo em Inglês | MEDLINE | ID: mdl-10753945

RESUMO

Matrix metalloproteinases (MMPs) are a family of secreted or transmembrane proteins that can degrade all the proteins of the extracellular matrix and have been implicated in many abnormal physiological conditions including arthritis and cancer metastasis. Recently we have shown for the first time that the human MMP-1 gene is a p53 target gene subject to repression by wild type p53 (Sun, Y., Sun, Y. I., Wenger, L., Rutter, J. L., Brinckerhoff, C. E., and Cheung, H. S. (1999) J. Biol. Chem. 274, 11535-11540). Here, we report that cotransfection of fibroblast-like synoviocytes with p53 expression and hMMP13CAT reporter plasmids revealed that (i) hMMP13, another member of the human MMP family, was down-regulated by wild type p53, whereas all six of the p53 mutants tested lost the wild type p53 repressor activity in fibroblast-like synoviocytes; (ii) this repression of hMMP-13 gene expression by wild type p53 could be reversed by overexpression of p53 mutants p53-143A, p53-248W, p53-273H, and p53-281G; (iii) the dominant effect of p53 mutants over wild type p53 appears to be a promoter- and mutant-specific effect. An intriguing finding was that p53 mutant p53-281G could conversely stimulate the promoter activity of hMMP13 up to 2-4-fold and that it was dominant over wild type p53. Northern analysis confirmed these findings. Although the significance of these findings is currently unknown, they suggest that in addition to the effect of cytokines activation, the gene expression of hMMP13 could be dysregulated during the disease progression of rheumatoid arthritis (or cancer) associated with p53 inactivation. Since hMMP13 is 5-10 times as active as hMMP1 in its ability to digest type II collagen, the dysregulation or up-modulation of MMP13 gene expression due to the inactivation of p53 may contribute to the joint degeneration in rheumatoid arthritis.


Assuntos
Colagenases/genética , Regulação Enzimológica da Expressão Gênica , Proteína Supressora de Tumor p53/fisiologia , Artrite Reumatoide/etiologia , Artrite Reumatoide/genética , Humanos , Metaloproteinase 13 da Matriz , Mutação , Regiões Promotoras Genéticas , Elementos de Resposta
9.
J Biol Chem ; 274(17): 11535-40, 1999 Apr 23.
Artigo em Inglês | MEDLINE | ID: mdl-10206959

RESUMO

Recent studies show that the p53 tumor suppressor protein is overexpressed in rheumatoid arthritis (RA) synovium and that somatic mutations previously identified in human tumors are present in RA synovium (Firestein, G. S., Echeverri, F., Yeo, M., Zvaifler, N. J., and Green, D. R. (1997) Proc. Natl. Acad. Sci. U. S. A. 94, 10895-10900; Firestein, G. S., Nguyen, K., Aupperle, K. R., Yeo, M., Boyle, D. L., and Zvaifler, N. J. (1996) Am. J. Pathol. 149, 2143-2151; Reme, T., Travaglio, A., Gueydon, E., Adla, L., Jorgensen, C., and Sany, J. (1998) Clin. Exp. Immunol. 111, 353-3581). We hypothesize that the abnormality of p53 seen in RA synovium may contribute to joint degeneration through the regulation of human matrix metalloproteinase-1 (hMMP-1, collagenase-1) gene expression. Transcription assays were performed with luciferase reporters driven by the promoter of the hMMP-1 gene or by a minimal promoter containing tandem repeats of the consensus binding sequence for activator protein-1, cotransfected with p53-expressing plasmids. The results revealed that (i) wild-type (wt) p53 down-regulated the promoter activity of hMMP-1 in a dose-dependent fashion; (ii) four of six p53 mutants (commonly found in human cancers) lost this repression activity; and (iii) this p53 repression activity was mediated at least in part by the activator protein-1 sites found in the hMMP-1 promoter. These findings were further confirmed by Northern analysis. The down-regulation of hMMP-1 gene expression by endogenous wt-p53 was shown by treatment of U2-OS cells, a wt-p53-containing osteogenic sarcoma line, and Saos-2 cells, a p53-negative osteogenic sarcoma line, with etoposide, a potent inducer of p53 expression. p53, activated by etoposide, appears to block hMMP-1 promoter activity induced by etoposide in U2-OS cells. In summary, we have shown for the first time that the hMMP-1 gene is a p53 target gene, subject to p53 repression. Because MMP-1 is principally responsible for the irreversible destruction of collagen in articular tissue in RA, abnormality of p53 may contribute to joint degeneration through the regulation of MMP-1 expression.


Assuntos
Colagenases/genética , Regulação Enzimológica da Expressão Gênica , Proteína Supressora de Tumor p53/metabolismo , Sítios de Ligação , Humanos , Metaloproteinase 1 da Matriz , Regiões Promotoras Genéticas , Fator de Transcrição AP-1/metabolismo , Transcrição Gênica
10.
Acta Histochem ; 99(4): 431-44, 1997 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-9429602

RESUMO

The objective of this study was to immunolocalize decorin and to assess changes as a result of pyridoxine (PN) deficiency in chick articular cartilage from femoral condyles. After maintenance on a normal diet for the first two weeks after hatching, 15 broiler chickens were deprived of this vitamin for 6 weeks. It was previously shown that the ankle joints of PN-deficient animals are swollen with effusions. They also present an abnormal gait, enlarged bony margins, and fissuring of the articular cartilages. Milder changes (no fissures) were also shown in the knee joints. Data from a previous study were suggestive that sulfated glycosaminoglycans are lost from the knee cartilage surface into synovial fluid. The current study was focused on the small proteoglycan, decorin, which coats the surface of collagen fibrils and may regulate their morphology. To examine decorin in normal and PN-deficient articular cartilage, a monoclonal antibody to an epitope on the protein core of decorin was used for immunohistochemical staining of tissue sections and for Western Blot analysis of cartilage extracts. Reduction of staining with the antibody was demonstrated in the tangential surface zone of PN-deficient cartilage, and Western Blot analysis showed reduced intensity of decorin bands compared to normal controls. These data suggest that a lack of decorin may play a role in the enlargement of collagen bundles in the tangential zone of PN-deficient articular cartilage as observed in a previous electron microscopic study.


Assuntos
Cartilagem Articular/patologia , Osteoartrite/etiologia , Proteoglicanas/metabolismo , Deficiência de Vitamina B 6/complicações , Animais , Western Blotting , Cartilagem Articular/química , Galinhas , Doenças do Colágeno/etiologia , Decorina , Proteínas da Matriz Extracelular , Imuno-Histoquímica , Masculino , Proteoglicanas/análise , Proteoglicanas/fisiologia , Distribuição Aleatória , Deficiência de Vitamina B 6/metabolismo , Deficiência de Vitamina B 6/patologia
11.
Bone ; 19(3): 255-61, 1996 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-8873966

RESUMO

Hepatocyte growth factor (HGF) has been implicated as a paracrine regulator of organogenesis and repair in many tissues. Here we have studied the expression and actions of HGF in intact rachitic rat growth plate and derived cultures of proliferative zone chondrocytes. In vivo and in vitro chondrocytes express HGF mRNA; 1,25(OH)2 has a three-fold maximal stimulatory effect, which can be blocked by H-7, an inhibitor of protein kinase C. Although HGF elaboration and action generally follow a paracrine model, chondrocytes appear capable of both expressing and responding to HGF. mRNA encoding the HGF receptor (c-met) was detected in both growth cartilage and derived chondrocyte cultures. HGF addition to chondrocyte cultures increased collagen II mRNA and alkaline phosphatase enzymatic activity to degrees comparable to that observed for active vitamin D metabolites. Combining HGF and 1,25-D evoked a synergistic response (ninefold) of alkaline phosphatase activity. To assess whether a similar stimulatory effect might be seen with bioactive peptides and HGF, we investigated the effect of HGF pretreatment on acute responses of chondrocytes to synthetic human calcitonin, an anabolic chondrocyte regulator whose skeletal action are mediated principally by cAMP elevation and subsequent protein kinase A activation. CT's maximal activation of protein kinase A was increased by prior HGF treatment from 56% to 78%. In concert, our findings indicate that in addition to HGF's classical paracrine role during skeletal growth, this growth factor may modulate hormonal sensitivity of the chondrocyte during proliferation, differentiation, and/or apoptosis.


Assuntos
Calcitriol/farmacologia , Regulação da Expressão Gênica/efeitos dos fármacos , Lâmina de Crescimento/efeitos dos fármacos , Fator de Crescimento de Hepatócito/genética , Fosfatase Alcalina/metabolismo , Animais , Células Cultivadas , Colágeno/genética , Proteínas Quinases Dependentes de AMP Cíclico/agonistas , Ativação Enzimática , Lâmina de Crescimento/citologia , Lâmina de Crescimento/metabolismo , Masculino , RNA Mensageiro/análise , Ratos , Ratos Sprague-Dawley
12.
Carcinogenesis ; 15(7): 1393-8, 1994 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-8033316

RESUMO

Earlier studies showed that urine of rats which had been injected with the methylating agent N-[3H-methyl]-N-nitrosourea contained a previously undetected metabolic product, 7-[3H-methyl]adenine. This methylpurine, undoubtedly derived from alkylation of nucleic acids followed by depurination, was not labeled when 14C-methyl-labeled methionine was administered concurrently. To establish whether urinary 7-methyladenine (7-MA) might serve as a marker of exposure to exogenous and carcinogenic methylating agents, the excretion of 7-MA following injection of methylating agents was measured. A GC-MS method, using pentafluorobenzyl derivatives and an internal standard of tri-deutero-7-MA, was developed to assay levels of 7-MA. Increasing the i.p. dose of N-methylnitrosourea (MNU) from 2 to 80 mg/kg/rat resulted in a linear increase in urinary 7-MA, which at the highest dose was 1.6 micrograms during the first day and another 0.4 microgram during day 2. Doses of 5 mg/kg MNU led to elevated urinary levels of 7-MA (144 ng) compared to controls (26 ng). Other methylating agents, such as dimethylnitrosamine, N-methyl-N'-nitro-N-nitrosoguanidine and dimethyl sulfate, also provided urinary 7-MA. To determine the fate of injected 7-MA, the administration of 2 micrograms 7-[3H-methyl]adenine led to an 80% recovery of radioactivity in the urine, almost all of it during the first 24 h. No other labeled metabolites were detected. At least for the rat, urinary 7-MA serves as an indicator of exposure to methylating agents.


Assuntos
Adenina/análogos & derivados , Alquilantes/metabolismo , Adenina/urina , Aflatoxina B1/metabolismo , Animais , Dimetilnitrosamina/metabolismo , Masculino , Metilnitronitrosoguanidina/metabolismo , Metilnitrosoureia/metabolismo , Ratos , Ratos Endogâmicos F344
13.
J Psychoactive Drugs ; 26(1): 1-11, 1994.
Artigo em Inglês | MEDLINE | ID: mdl-8027902

RESUMO

Drug treatment on demand, appropriate and affordable drug treatment for injection drug users who are "ready" to enter a program, is a humane approach to drug treatment services and an important mechanism to halt the spread of HIV. However, drug treatment on demand is not a reality in the United States. In fact, due to funding cuts at federal, state, and local levels, entry into drug treatment programs has become increasingly more difficult over the past decade. In a NIDA-funded ethnographic study of methadone maintenance, i.v. drug use and AIDS, 70 heroin addicts who were out of treatment and actively seeking methadone maintenance were interviewed. In life-history interviews, the drug users described barriers to treatment, waiting-list experiences, and the impact of these experiences on their drug use, drug-using behavior, and emotional well-being. Respondents used many mechanisms to cope with the lack of availability of drug treatment slots, some of which have increased their risk of exposure to and spread of HIV. These findings indicate the need for an increase in the availability of subsidized methadone maintenance treatment slots "on demand" if individuals are to decrease their drug use and their high-risk behaviors. Drug treatment on demand is more than politically correct rhetoric. It is a necessary ingredient in reducing the harm caused by the use of illegal drugs.


Assuntos
Abuso de Substâncias por Via Intravenosa/reabilitação , Adaptação Psicológica , Adulto , Etnicidade , Feminino , Infecções por HIV/prevenção & controle , Infecções por HIV/transmissão , Dependência de Heroína/reabilitação , Humanos , Masculino , Metadona/uso terapêutico , Pessoa de Meia-Idade , Assunção de Riscos , Abuso de Substâncias por Via Intravenosa/complicações , Abuso de Substâncias por Via Intravenosa/etnologia , Estados Unidos , Listas de Espera
14.
Proc Natl Acad Sci U S A ; 89(7): 3000-4, 1992 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-1557405

RESUMO

The synthesis of the nuclear lamina protein lamin A requires the prenylation-dependent processing of its precursor protein, prelamin A. Unlike p21ras, which undergoes similar initial posttranslational modifications, maturation of lamin A results in the proteolytic removal of the prenylated portion of the molecule. We have used an in vitro prenylation system to demonstrate the nature of the prenyl substituent on prelamin A to be a farnesyl group. Further, the in vitro farnesylation of prelamin A requires an intact cysteine-aliphatic-aliphatic-other (CAAX) amino acid sequence motif at its carboxyl terminus. The effect of blocking the prenylation of prelamin A on its localization and assembly into the nuclear lamina was investigated by indirect immunofluorescence. Expression of wild-type prelamin A in lovastatin-treated cells showed that nonprenylated prelamin A accumulated as nucleoplasmic particles. Upon addition of mevalonate to lovastatin-treated cells, the wild-type lamin A was incorporated into the lamina within 3 hr. Expression of a mutant lamin A in which the carboxyl-terminal 21 amino acids were deleted resulted in a lamin molecule that was directly assembled into the lamina. These results indicate that the carboxyl-terminal peptide of prelamin A blocks its proper assembly into the nuclear lamina and that the prenylation-initiated removal of this peptide can occur in the nucleus.


Assuntos
Núcleo Celular/metabolismo , Proteínas Nucleares/metabolismo , Precursores de Proteínas/metabolismo , Processamento de Proteína Pós-Traducional/efeitos dos fármacos , Animais , Células CHO , Compartimento Celular , Cricetinae , Farneseno Álcool/metabolismo , Lamina Tipo A , Laminas , Lovastatina/farmacologia , Membrana Nuclear/metabolismo , Proteínas Recombinantes , Relação Estrutura-Atividade
15.
J Biol Chem ; 265(24): 14118-26, 1990 Aug 25.
Artigo em Inglês | MEDLINE | ID: mdl-2117604

RESUMO

The Chinese hamster ovary recessive mutant, crB, has been selected for its resistance to the cytotoxic effects of 25-hydroxycholesterol in sterol-free media (Sinensky, M., Logel, J., and Torget, R. (1982) J. Cell. Physiol. 113, 314-319). Growth of crB in a chemically defined lipid-poor medium is very slow and is enhanced by a mixture of saturated and unsaturated fatty acids. Incorporation of [3H]acetate into total fatty acids is 4-fold lower in crB compared to that in parental Chinese hamster ovary K1 and in contrast to the wild-type cells, crB cells are unable to synthesize either stearate or oleate. In addition, crB cells can not elongate exogenous palmitate, while they are capable of desaturating exogenous stearate. The mutant cells are also pleiotropically defective in the regulation of mRNA levels for the enzymes of cholesterol biosynthesis. 25-Hydroxycholesterol is a poor regulator of the synthesis and degradation of the rate-limiting enzyme, 3-hydroxy-3-methylglutaryl-coenzyme A reductase in crB in comparison to the wild-type Chinese hamster ovary K1 cells. The defect in the elongation of fatty acids is reversed in revertants of crB selected for their ability to grow in lipid-poor medium. Such revertants exhibit normal regulation of 3-hydroxy-3-methylglutaryl-CoA reductase activity by 25-hydroxycholesterol. Regulation of reductase activity in crB cells can also be restored by supplementing the culture medium with a mixture of fatty acids that restores normal growth rate. The defective regulation of reductase in crB does not appear to be due to nonspecific adverse effects of fatty acid starvation nor is it due to any gross change in the fatty acid composition of cellular phospholipids. These results strongly suggest a direct relationship between the fatty acid auxotrophy of crB and defective regulation of the enzymes of cholesterol biosynthesis.


Assuntos
Ácidos Graxos/biossíntese , Hidroxicolesteróis/farmacologia , Hidroximetilglutaril-CoA Redutases/metabolismo , Mutação , Acetatos/metabolismo , Animais , Afidicolina , Divisão Celular/efeitos dos fármacos , Linhagem Celular , Cricetinae , Cricetulus , Diterpenos/farmacologia , Resistência a Medicamentos/genética , Repressão Enzimática , Feminino , Genes Recessivos , Hidroximetilglutaril-CoA Redutases/biossíntese , Inositol/farmacologia , Cinética , Ovário , Esterol O-Aciltransferase/metabolismo
16.
J Cell Physiol ; 94(1): 69-75, 1978 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-201654

RESUMO

The reverse transformation reaction of Chinese hamster ovary cells from compact, epithelial-like, randomly growing, heavily knobbed, lectin reactive cells into stretched, tighly adherent, smooth-surfaced, lectin resistant, fibroblast-like cells normally elicited by dibutyryl cAMP can be produced to its complete extent by N6-monobutyryl cAMP or 8-bromo-cAMP, O2'-monobutyryl cAMP is ineffective as is cAMP itself in the absence of an inhibitor of phosphodiesterase activity. In the presence of a phosphodiesterase inhibitor, cAMP is fully effective. These results indicate that the role of the butyryl groups of dibutyryl cAMP and, especially, the N6-butyryl, in the reverse transformation reaction is protection of the cAMP analogue from degradation. Butyrate at concentrations of about 1 mM does produce a response which to some extent mimics that of cAMP analogues. The cells, however, fail to assume a fibroblastic-like shape, but rather become flattened. The butyrate effect is much slower and less readily reversible than that evoked by cAMP analogues. Butyrate produces an approximately 2-fold increase in intracellular cAMP levels. These results are consistent with the hypothesis that butyrate effects, in part, are mediated by AMP.


Assuntos
Butiratos/farmacologia , Transformação Celular Neoplásica/efeitos dos fármacos , Linhagem Celular , Concanavalina A/farmacologia , AMP Cíclico/análogos & derivados , AMP Cíclico/metabolismo , AMP Cíclico/farmacologia , Testolactona/farmacologia , Teofilina/farmacologia
17.
Nature ; 253(5490): 377-8, 1975 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-1110783
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