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1.
Clin Nutr ; 38(6): 2477-2498, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-30685297

RESUMO

BACKGROUND & AIMS: Malnutrition in older adults results in significant personal, social, and economic burden. To combat this complex, multifactorial issue, evidence-based knowledge is needed on the modifiable determinants of malnutrition. Systematic reviews of prospective studies are lacking in this area; therefore, the aim of this systematic review was to investigate the modifiable determinants of malnutrition in older adults. METHODS: A systematic approach was taken to conduct this review. Eight databases were searched. Prospective cohort studies with participants of a mean age of 65 years or over were included. Studies were required to measure at least one determinant at baseline and malnutrition as outcome at follow-up. Study quality was assessed using a modified version of the Quality in Prognosis Studies (QUIPS) tool. Pooling of data in a meta-analysis was not possible therefore the findings of each study were synthesized narratively. A descriptive synthesis of studies was used to present results due the heterogeneity of population source and setting, definitions of determinants and outcomes. Consistency of findings was assessed using the schema: strong evidence, moderate evidence, low evidence, and conflicting evidence. RESULTS: Twenty-three studies were included in the final review. Thirty potentially modifiable determinants across seven domains (oral, psychosocial, medication and care, health, physical function, lifestyle, eating) were included. The majority of studies had a high risk of bias and were of a low quality. There is moderate evidence that hospitalisation, eating dependency, poor self-perceived health, poor physical function and poor appetite are determinants of malnutrition. Moderate evidence suggests that chewing difficulties, mouth pain, gum issues co-morbidity, visual and hearing impairments, smoking status, alcohol consumption and physical activity levels, complaints about taste of food and specific nutrient intake are not determinants of malnutrition. There is low evidence that loss of interest in life, access to meals and wheels, and modified texture diets are determinants of malnutrition. Furthermore, there is low evidence that psychological distress, anxiety, loneliness, access to transport and wellbeing, hunger and thirst are not determinants of malnutrition. There appears to be conflicting evidence that dental status, swallowing, cognitive function, depression, residential status, medication intake and/or polypharmacy, constipation, periodontal disease are determinants of malnutrition. CONCLUSION: There are multiple potentially modifiable determinants of malnutrition however strong robust evidence is lacking for the majority of determinants. Better prospective cohort studies are required. With an increasingly ageing population, targeting modifiable factors will be crucial to the effective treatment and prevention of malnutrition.


Assuntos
Desnutrição , Idoso , Idoso de 80 Anos ou mais , Cognição , Exercício Físico , Feminino , Hospitalização , Humanos , Masculino , Desnutrição/epidemiologia , Desnutrição/fisiopatologia , Desnutrição/psicologia , Fatores de Risco
2.
Ir J Med Sci ; 186(4): 855-857, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-28185061

RESUMO

BACKGROUND: EGFR mutated lung cancer represents a subgroup with distinct clinical presentations, prognosis, and management requirements. We investigated the survival, prognostic factors, and real-world treatment of NSCLC patients with EGFR mutation in clinical practice. METHODS: A retrospective review of all specimens sent for EGFR analysis from December 2009 to September 2015 was performed. Patient demographics, specimen type, EGFR mutation status/type, stage at diagnosis, treatment, response rate, and survival data were recorded. RESULTS: 27/334 (8%) patient specimens sent for EGFR testing tested positive for a sensitising EGFR mutation. The median age was 65 years (40-85 years). Exon 19 deletion represented the most commonly detected alteration, accounting for 39% (n = 11). First-line treatment for those with Exon 18, 19, or 21 alterations (n = 24) was with an EGFR tyrosine kinase inhibitor (TKI) in 79% (n = 19). Objective response rate among these patients was 74% and median duration of response was 13 months (range 7-35 months). CONCLUSION: The incidence of EGFR mutation in our cohort of NSCLC is 9% which is consistent with mutation incidence reported in other countries. The rate of EGFR mutation in our population is slightly below that reported internationally, but treatment outcomes are consistent with published data. Real-world patient data have important contributions to make with regard to quality measurement, incorporating patient experience into guidelines and identifying safety signals.


Assuntos
Carcinoma Pulmonar de Células não Pequenas/genética , Receptores ErbB/genética , Neoplasias Pulmonares/genética , Mutação , Adulto , Idoso , Idoso de 80 Anos ou mais , Carcinoma Pulmonar de Células não Pequenas/epidemiologia , Carcinoma Pulmonar de Células não Pequenas/patologia , Estudos de Coortes , Feminino , Humanos , Incidência , Irlanda/epidemiologia , Neoplasias Pulmonares/epidemiologia , Neoplasias Pulmonares/patologia , Masculino , Pessoa de Meia-Idade , Prognóstico , Estudos Retrospectivos , Resultado do Tratamento
3.
Neuroscience ; 201: 20-33, 2012 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-22133893

RESUMO

The serotonergic centrifugal system innervating the main olfactory bulb (MOB) plays a key role in the modulation of olfactory processing. We have previously demonstrated that this system suffers adaptive changes under conditions of a lack of olfactory input. The present work examines the response of this centrifugal system after mitral cell loss in the Purkinje cell degeneration (pcd) mutant mice. The distribution and density of serotonergic centrifugal axons were studied in the MOB of control and pcd mice, both before and after the loss of mitral cells, using serotonin (5-HT) and 5-HT transporter immunohistochemistry. Studies of the amount of 5-HT and its metabolite, 5-hydroxyindole acetic acid (5-HIAA), were performed by means of high-performance liquid chromatography (HPLC), and the relative amounts of brain-derived neurotrophin factor, BDNF, and its major receptor, tropomyosin-related kinase B (TrkB), were measured by Western blot. Our study revealed that the serotonergic system develops adaptive changes after, but not before, mitral cell loss. The lack of the main bulbar projection cells causes a decrease in the serotonergic input received by the MOB, whereas the number of serotonergic cells in the raphe nuclei remains constant. In addition, one of the molecules directly involved in serotonergic sprouting, the neurotrophin BDNF and its main receptor TrkB, underwent alterations in the MOBs of the pcd animals even before the loss of mitral cells. These data indicate that serotonergic function in the MOB is closely related to olfactory activity and that mitral cell loss induces serotonergic plastic responses.


Assuntos
Degeneração Neural/patologia , Bulbo Olfatório/metabolismo , Bulbo Olfatório/patologia , Células de Purkinje/patologia , Serotonina/metabolismo , Trifosfato de Adenosina/genética , Fatores Etários , Animais , Contagem de Células , Morte Celular/genética , Morte Celular/fisiologia , Cromatografia Líquida de Alta Pressão , Proteínas de Ligação ao GTP/genética , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Mutantes Neurológicos , Degeneração Neural/genética , Condutos Olfatórios/fisiologia , Receptor trkB/metabolismo , D-Ala-D-Ala Carboxipeptidase Tipo Serina/genética , Proteínas da Membrana Plasmática de Transporte de Serotonina/metabolismo , Estatísticas não Paramétricas
4.
Br J Haematol ; 116(3): 645-8, 2002 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-11849225

RESUMO

Surgical resection is the only definitive treatment for haemophilic pseudotumour. For patients with high- responding factor (F)VIII inhibitors, the lack of reliable by-passing agents in the past has meant that surgery has been avoided in favour of conservative measures. The development of recombinant factor VIIa (rFVIIa) has revolutionized the management of surgery in these patients. We document the first successful report of the surgical resection of a massive pseudotumour in a patient with high responding FVIII inhibitors using rFVIIa to achieve haemostasis. Serial post-operative measurements indicated that FVII coagulation activity (FVII:C) levels were more sensitive to rFVIIa dose changes than the prothrombin time.


Assuntos
Fator VII/uso terapêutico , Granuloma de Células Plasmáticas/cirurgia , Hemofilia A/complicações , Hemostasia Cirúrgica/métodos , Doenças Musculares/cirurgia , Proteínas Recombinantes/uso terapêutico , Adulto , Antígenos/sangue , Perda Sanguínea Cirúrgica/prevenção & controle , Fator VIIa , Granuloma de Células Plasmáticas/etiologia , Humanos , Masculino , Doenças Musculares/etiologia
5.
Mol Cell Biol ; 21(19): 6695-705, 2001 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-11533256

RESUMO

In response to phosphate limitation, Saccharomyces cerevisiae induces transcription of a set of genes important for survival. A phosphate-responsive signal transduction pathway mediates this response by controlling the activity of the transcription factor Pho4. Three components of this signal transduction pathway resemble those used to regulate the eukaryotic cell cycle: a cyclin-dependent kinase (CDK), Pho85; a cyclin, Pho80; and a CDK inhibitor (CKI), Pho81. Pho81 forms a stable complex with Pho80-Pho85 under both high- and low-phosphate conditions, but it only inhibits the kinase when cells are starved for phosphate. Pho81 contains six tandem repeats of the ankyrin consensus domain homologous to the INK4 family of mammalian CKIs. INK4 proteins inhibit kinase activity through an interaction of the ankyrin repeats and the CDK subunits. Surprisingly, we find that a region of Pho81 containing 80 amino acids C terminal to the ankyrin repeats is necessary and sufficient for Pho81's CKI function. The ankyrin repeats of Pho81 appear to have no significant role in Pho81 inhibition. Our results suggest that Pho81 inhibits Pho80-Pho85 with a novel motif.


Assuntos
Quinases Ciclina-Dependentes/antagonistas & inibidores , Proteínas Fúngicas/química , Proteínas Fúngicas/fisiologia , Proteínas Repressoras , Proteínas de Saccharomyces cerevisiae , Saccharomyces cerevisiae/metabolismo , Sequência de Aminoácidos , Núcleo Celular/metabolismo , Ciclina A/química , Ciclinas/química , Ciclinas/genética , Ciclinas/fisiologia , Proteínas Fúngicas/genética , Dados de Sequência Molecular , Mutagênese Sítio-Dirigida , Fosfatos/metabolismo , Biossíntese de Proteínas , Estrutura Terciária de Proteína , Saccharomyces cerevisiae/genética , Deleção de Sequência , Homologia de Sequência de Aminoácidos , Relação Estrutura-Atividade , Transcrição Gênica
6.
Curr Opin Cell Biol ; 12(3): 355-60, 2000 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-10801461

RESUMO

The compartmentalization of DNA in the nucleus of eukaryotic cells establishes a connection between the nuclear transport machinery and the transcriptional apparatus. General transcription factors, as well as specific transcriptional activators and repressors, such as p53 and NF-AT, need to be imported into the nucleus following their translation. In addition, nuclear transport plays a crucial role in regulating the activity of many transcription factors.


Assuntos
Núcleo Celular/metabolismo , Proteínas Nucleares , Proteínas de Saccharomyces cerevisiae , Transcrição Gênica , Transporte Biológico Ativo , DNA/genética , DNA/metabolismo , Proteínas de Ligação a DNA/metabolismo , Proteínas Fúngicas/metabolismo , Humanos , Fatores de Transcrição NFATC , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Proteína de Ligação a TATA-Box , Fator de Transcrição TFIIA , Fatores de Transcrição/metabolismo , Proteína Supressora de Tumor p53/metabolismo
7.
Haemophilia ; 6(2): 113-5, 2000 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-10781199

RESUMO

The development of high responding inhibitors is an increasingly recognized complication of mild Haemophilia. Inhibitors tend to develop in adolescence and adulthood and this is frequently preceded by high-intensity factor replacement therapy. We report two patients with mild Haemophilia who developed high responding inhibitors after continuous infusion with recombinant factor VIII (Kogenate) as prophylaxis for surgery. We discuss whether recent changes in clinical practice could be responsible for the apparent increase in high responding inhibitors in mild Haemophilia.


Assuntos
Fator VIII/administração & dosagem , Fator VIII/antagonistas & inibidores , Hemofilia A/metabolismo , Adulto , Fator VIII/uso terapêutico , Hemofilia A/cirurgia , Hemorragia/tratamento farmacológico , Hemorragia/etiologia , Humanos , Infusões Parenterais/efeitos adversos , Isoanticorpos/efeitos adversos , Isoanticorpos/sangue , Masculino , Complicações Pós-Operatórias/prevenção & controle , Proteínas Recombinantes/administração & dosagem , Proteínas Recombinantes/uso terapêutico
9.
Oncologist ; 4(3): 256-62, 1999.
Artigo em Inglês | MEDLINE | ID: mdl-10394593

RESUMO

Shortly before his death in 1995, Kenneth B. Schwartz, a cancer patient at Massachusetts General Hospital (MGH), founded The Kenneth B. Schwartz Center at MGH. The Schwartz Center is a non-profit organization dedicated to supporting and advancing compassionate health care delivery which provides hope to the patient, support to caregivers, and encourages the healing process. The Center sponsors the Schwartz Center Rounds, a monthly multidisciplinary forum where caregivers reflect on important psychosocial issues faced by patients, their families, and their caregivers, and gain insight and support from fellow staff members. The following case of a woman who developed lymphoma was discussed at the July and August, 1997 Schwartz Center Rounds. There were considerable delays and uncertainties in the diagnosis, which was followed by an unpredictably chaotic clinical course. Although she had made it clear to her doctor that she did not want "heroic measures," she had unexpectedly rallied so many times that her son and her husband wanted her doctors to do everything possible to keep her alive, including the performance of cardiopulmonary resuscitation (CPR). The clinical benefit of CPR in the event of cardiac arrest in those with cancer is discussed, as are do not resuscitate (DNR) orders, living wills, and healthcare proxies. In addition, the issues that surround DNR status, including who should discuss DNR status with a patient, and how and when it should be discussed, are reviewed. Staff raised concerns about the effect of discussing DNR status on the doctor-patient relationship, and wondered whether writing DNR orders adversely affect the care of patients.


Assuntos
Diretivas Antecipadas , Cuidadores , Relações Médico-Paciente , Ordens quanto à Conduta (Ética Médica) , Tomada de Decisões , Saúde da Família , Feminino , Humanos , Linfoma , Pessoa de Meia-Idade , Prognóstico , Estresse Psicológico
10.
Oncologist ; 4(2): 122-7, 1999.
Artigo em Inglês | MEDLINE | ID: mdl-10337382

RESUMO

Shortly before his death in 1995, Kenneth B. Schwartz, a cancer patient at Massachusetts General Hospital (MGH), founded The Kenneth B. Schwartz Center at MGH. The Schwartz Center is a non-profit organization dedicated to supporting and advancing compassionate health care delivery which provides hope to the patient, support to caregivers, and encourages the healing process. The Center sponsors the Schwartz Center Rounds, a monthly multidisciplinary forum during which caregivers discuss a specific cancer patient, reflect on the important psychosocial issues faced by patients, their families, and their caregivers, and gain insight and support from their fellow staff members. The case presented was of a 31-year-old man who developed adenocarcinoma of the lung with painful bone metastases. His tumor was unresponsive to treatment and he subsequently committed suicide by shooting himself. The verbatim and subsequent discussion raised a number of issues. Staff were devastated by the violent way that he ended his life. They questioned whether more could have been done to prevent this outcome, yet acknowledged that it mirrored the way he had lived, and were able to discuss the values by which we live and die. Some, but not all, felt that the patient had the right to choose how and when to end his life.


Assuntos
Adenocarcinoma/psicologia , Cuidadores/psicologia , Neoplasias Pulmonares/psicologia , Neoplasias da Coluna Vertebral/psicologia , Suicídio/psicologia , Adenocarcinoma/secundário , Adulto , Atitude Frente a Morte , Humanos , Vértebras Lombares , Neoplasias Pulmonares/patologia , Masculino , Dor/tratamento farmacológico , Dor/psicologia , Personalidade , Neoplasias da Coluna Vertebral/secundário , Cônjuges/psicologia , Suicídio Assistido/psicologia , Vértebras Torácicas
11.
Mol Cell Biol ; 19(4): 2817-27, 1999 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-10082547

RESUMO

The Saccharomyces cerevisiae gene PHO5 is an excellent system with which to study regulated changes in chromatin structure. The PHO5 promoter is packaged into four positioned nucleosomes under repressing conditions; upon induction, the structure of these nucleosomes is altered such that the promoter DNA becomes accessible to nucleases. We report here the development and characterization of an in vitro system in which partially purified PHO5 minichromosomes undergo promoter chromatin remodeling. Several hallmarks of the PHO5 chromatin transition in vivo were reproduced in this system. Chromatin remodeling of PHO5 minichromosomes required the transcription factors Pho4 and Pho2, was localized to the promoter region of PHO5, and was independent of the chromatin-remodeling complex Swi-Snf. In vitro chromatin remodeling also required the addition of fractionated nuclear extract and hydrolyzable ATP. This in vitro system should serve as a useful tool for identifying the components required for this reaction and for elucidating the mechanism by which the PHO5 promoter chromatin structure is changed.


Assuntos
Fosfatase Ácida/genética , Cromatina/metabolismo , Cromossomos Fúngicos/metabolismo , Proteínas de Ligação a DNA , Proteínas de Homeodomínio , Regiões Promotoras Genéticas , Proteínas de Saccharomyces cerevisiae , Saccharomyces cerevisiae/genética , Fatores de Transcrição , Trifosfato de Adenosina/metabolismo , Sítios de Ligação , Núcleo Celular/metabolismo , Sistema Livre de Células , Proteínas Fúngicas/metabolismo , Regulação Fúngica da Expressão Gênica , Nucleossomos/metabolismo , Plasmídeos , Saccharomyces cerevisiae/enzimologia , Frações Subcelulares/metabolismo , Transativadores/metabolismo
12.
Genetics ; 150(4): 1349-59, 1998 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-9832515

RESUMO

In the yeast Saccharomyces cerevisiae, transcription of a secreted acid phosphatase, PHO5, is repressed in response to high concentrations of extracellular inorganic phosphate. To investigate the signal transduction pathway leading to transcriptional regulation of PHO5, we carried out a genetic selection for mutants that express PHO5 constitutively. We then screened for mutants whose phenotypes are also dependent on the function of PHO81, which encodes an inhibitor of the Pho80p-Pho85p cyclin/cyclin-dependent kinase complex. These mutations are therefore likely to impair upstream functions in the signaling pathway, and they define five complementation groups. Mutations were found in a gene encoding a plasma membrane ATPase (PMA1), in genes required for the in vivo function of the phosphate transport system (PHO84 and PHO86), in a gene involved in the fatty acid synthesis pathway (ACC1), and in a novel, nonessential gene (PHO23). These mutants can be classified into two groups: pho84, pho86, and pma1 are defective in high-affinity phosphate uptake, whereas acc1 and pho23 are not, indicating that the two groups of mutations cause constitutive expression of PHO5 by distinct mechanisms. Our observations suggest that these gene products affect different aspects of the signal transduction pathway for PHO5 repression.


Assuntos
Fosfatase Ácida/genética , Proteínas de Transporte , Regulação Enzimológica da Expressão Gênica , Regulação Fúngica da Expressão Gênica , Proteínas de Saccharomyces cerevisiae , Saccharomyces cerevisiae/enzimologia , Transdução de Sinais , Acetiltransferases/genética , Proteínas Adaptadoras de Transporte Vesicular , Alelos , Ácidos Graxos/metabolismo , Proteínas Fúngicas/genética , Concentração de Íons de Hidrogênio , Proteínas de Membrana/genética , Mutagênese , Fenótipo , Fosfatos/metabolismo , ATPases Translocadoras de Prótons/genética , Saccharomyces cerevisiae/genética , Transcrição Gênica
13.
Br J Haematol ; 101(3): 475-9, 1998 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-9633889

RESUMO

The haemophilias are a group of inherited haemostatic disorders that require regular clotting factor replacement therapy in the severe and moderately severe subgroups. Prior to the introduction of adequate viral inactivation methods in 1985, haemophilia patients were at exceptionally high risk of contracting blood-borne viruses from factor concentrates as each batch was derived from the plasma of thousands of donors. As a result, approximately 60% of these patients were infected with HIV between 1979 and 1985, and HIV infection now contributes significantly to the morbidity and mortality seen in this group. Protease inhibitors (PIs) have been shown to significantly log reduce viral loads and increase CD4 cell counts in HIV-infected individuals. Recently, there has been concern about their use in HIV-infected haemophilia patients following increased bleeding episodes in some patients during PI therapy. We prospectively studied the effect of PI therapy in 20 HIV-infected haemophilia patients at our centre over a 6-month period. The mean increase in CD4 cell count was 70 x 10(6)/l and the mean log decrease in viral load was 1.59 over the study period. Gastrointestinal side-effects (nausea and vomiting in five, diarrhoea in two) were the most frequent and resulted in discontinuation of the medication in two patients. Factor concentrate usage for the group on and off study was similar. One severe FVIII patient reported a single episode of an unusual bleed which responded promptly to FVIII concentrate infusion. The significant clinical and laboratory benefits in terms of HIV disease and the paucity of added bleeding complications suggest that PI therapy should not be withheld from HIV-infected haemophilics. Further prospective studies evaluating the efficacy and possible haemostatic complications related to these promising inhibitors of the HIV protease are needed.


Assuntos
Infecções por HIV/tratamento farmacológico , Hemofilia A/virologia , Inibidores de Proteases/uso terapêutico , Infecções Oportunistas Relacionadas com a AIDS/induzido quimicamente , Contagem de Linfócito CD4 , Candidíase/induzido quimicamente , HIV/isolamento & purificação , Infecções por HIV/complicações , Hemofilia A/complicações , Transtornos Hemorrágicos/etiologia , Humanos , Estudos Prospectivos , Inibidores de Proteases/efeitos adversos , RNA Viral/análise , Resultado do Tratamento , Tuberculose Pulmonar/induzido quimicamente , Carga Viral
15.
Actas Urol Esp ; 17(9): 588-91, 1993 Oct.
Artigo em Espanhol | MEDLINE | ID: mdl-8165941

RESUMO

The fibroepithelial polyp of the ureter is a benign tumour with a mesenchymal origin. Since its incidence is low, there are very few cases published in the national literature. Presentation of our series, which consists of three cases seen and treated in our service over the last 10 years. Discussion of the most frequent characteristics seen in this type of disease and emphasis on its great relevance for the differential diagnosis with other causes of ureteral repletion deficiency.


Assuntos
Pólipos/patologia , Neoplasias Ureterais/patologia , Adulto , Diagnóstico Diferencial , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Pólipos/cirurgia , Ureter/patologia , Ureter/cirurgia , Neoplasias Ureterais/cirurgia
16.
Curr Biol ; 3(10): 658-67, 1993 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-15335856

RESUMO

BACKGROUND: The leucine zipper is a protein structural motif involved in the dimerization of a number of transcription factors. We have previously shown that peptides corresponding to the leucine-zipper region of the Fos and Jun oncoproteins preferentially form heterodimeric coiled coils, and that simple principles involving electrostatic interactions are likely to determine the pairing specificity of coiled coils. A critical test of these principles is to use them as guidelines to design peptides with desired properties. RESULTS: Based on studies of the Fos, Jun and GCN4 leucine zippers, we have designed two peptides that are predominantly unfolded in isolation but which, when mixed, associate preferentially to form a stable, parallel, coiled-coil heterodimer. To favor heterodimer formation, we chose peptide sequences that would be predicted to give destabilizing electrostatic interactions in the homodimers that would be relieved in the heterodimer. The peptides have at least a 10(5)-fold preference for heterodimer formation, and the dissociation constant of the heterodimer in phosphate-buffered saline is approximately 30 nM at pH 7 and 20 degrees C. Studies of the pH and ionic strength dependence of stability confirm that heterodimer formation is favored largely as a result of electrostatic destabilization of the homodimers. CONCLUSIONS: Our successful design strategy supports previous conclusions about the mechanism of interaction between the Fos and Jun oncoproteins. These results have implications for protein design, as they show that it is possible to design peptides with simple sequences that have a very high preference to pair with one another. Finally, these sequences with 'Velcro'-like properties may have practical applications, including use as an affinity reagent, in lieu of an epitope tag, or as a way of bringing together two molecules in a cell.

17.
Cell ; 68(4): 699-708, 1992 Feb 21.
Artigo em Inglês | MEDLINE | ID: mdl-1739975

RESUMO

Fos and Jun, the protein products of the nuclear proto-oncogenes c-fos and c-jun, associate preferentially to form a heterodimer that binds to DNA and modulates transcription of a wide variety of genes in response to mitogenic stimuli. Both Fos and Jun contain a single leucine zipper region. Previous studies have shown that the leucine zippers of Fos and Jun are necessary and sufficient to mediate preferential heterodimer formation. The leucine zipper regions from Fos and Jun are also known to fold autonomously, most likely as two-stranded, parallel coiled coils. We show here that 8 amino acids from Fos and from Jun are sufficient to mediate preferential heterodimer formation in a background of the GCN4 leucine zipper sequence. Using pH titration and amino acid replacements, we also show that destabilization of the Fos homodimer by acidic residues provides a major thermodynamic driving force for preferential heterodimer formation.


Assuntos
Proteínas Proto-Oncogênicas c-fos/química , Proteínas Proto-Oncogênicas c-jun/química , Sequência de Aminoácidos , Concentração de Íons de Hidrogênio , Zíper de Leucina , Modelos Moleculares , Dados de Sequência Molecular , Estrutura Molecular , Conformação Proteica , Termodinâmica
18.
Proc Natl Acad Sci U S A ; 88(2): 561-4, 1991 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-1988953

RESUMO

Dimerization of the bZIP class of eukaryotic transcriptional control proteins requires a sequence motif called the leucine zipper. We have grown two distinct crystal forms of a 33-amino acid peptide corresponding to the leucine zipper of the yeast transcriptional activator GCN4. This peptide is known to form a dimer of parallel helices in solution. X-ray scattering from both crystal forms shows reflections that are diagnostic of coiled coils. The most notable reflections occur at approximately 5.2 A resolution and correspond to the pitch of helices in coiled coils. There is no diffraction maximum near 5.4 A, the characteristic pitch of straight helices. Our results provide direct evidence that the leucine zipper of GCN4 is a coiled coil.


Assuntos
Zíper de Leucina , Peptídeos/química , Sequência de Aminoácidos , Cristalização , Dados de Sequência Molecular , Peptídeos/síntese química , Conformação Proteica , Difração de Raios X
19.
Actas Urol Esp ; 15(1): 90-4, 1991.
Artigo em Espanhol | MEDLINE | ID: mdl-2058451

RESUMO

Presentation of a case of prostatic infiltration by malignant lymphoma, discovered through manifestation of simple urinary symptomatology. The paper describes the diagnostic process followed, and includes reproduction of the most interesting findings. The rarity of this disorder and the good response obtained from the alternative chemotherapeutic therapy is emphasized.


Assuntos
Linfoma não Hodgkin/diagnóstico por imagem , Neoplasias da Próstata/diagnóstico por imagem , Adulto , Humanos , Masculino , Radiografia
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