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1.
Osteoporos Int ; 32(11): 2361-2364, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-33950266

RESUMO

Vertebral fractures (VF) related to osteoporosis (i.e., severe OP) increase the risk of disability and mortality, but they are often neglected. We observed a severe OP misdiagnosis in 28.9% of inpatients with previous spinal imaging positive for VFs. Diagnosing severe OP is crucial to reduce the health care costs of inpatients. INTRODUCTION: Vertebral fractures (VFs) related to osteoporosis (OP) increase the risk of additional fractures and death. In inpatients, VFs are often neglected with consequent delay in OP treatments, prolongation of hospitalization, and reduction of life expectancy. The aim of this study was to evaluate the prevalence of a misdiagnosed severe OP (i.e., with VF) in general medicine inpatients. METHODS: We evaluated inpatients of a Medicine Unit between January 2019 and December 2019 without severe OP diagnosis, who had spinal imaging. For each patient, we collected demographic data, previous or current OP treatment, and presence/number of VFs. Descriptive data were presented by medians (interquartile range [IQR]) for continuous data or as numbers (percentages) for categorical data. Differences between subgroups were analyzed with chi-square or Kruskal-Wallis tests as appropriate. p-values <0.05 were considered statistically significant. RESULTS: 793 subjects were admitted to inpatient's clinic: 235 (135 females and 100 males with a median age of 76.0 [64.0-83.0] years) were enrolled. One or more vertebral fractures were present in 28.9% (68/235) subjects; 47% (32/68) had two or more vertebral fractures. The majority of patients (55/68) with VFs had not previously received a severe OP diagnosis. CONCLUSIONS: Severe OP was misdiagnosed in at least 8.6% of inpatients. The prevalence dramatically increases (about 29%) in subjects with previous spinal imaging showing one or more VFs. More attention should be given to this co-morbidity, which is known to be an additional risk factor for disability and mortality.


Assuntos
Osteoporose , Fraturas por Osteoporose , Fraturas da Coluna Vertebral , Absorciometria de Fóton , Idoso , Idoso de 80 Anos ou mais , Estudos Transversais , Erros de Diagnóstico , Feminino , Humanos , Pacientes Internados , Medicina Interna , Masculino , Pessoa de Meia-Idade , Osteoporose/diagnóstico , Osteoporose/epidemiologia , Fraturas por Osteoporose/diagnóstico , Fraturas por Osteoporose/epidemiologia , Fraturas por Osteoporose/etiologia , Prevalência , Fraturas da Coluna Vertebral/diagnóstico por imagem , Fraturas da Coluna Vertebral/epidemiologia
2.
Tech Coloproctol ; 20(5): 299-307, 2016 May.
Artigo em Inglês | MEDLINE | ID: mdl-27037709

RESUMO

BACKGROUND: As stapled hemorrhoidopexy (SH) becomes more widely used, we see more patients with chronic postoperative anal pain after this surgery. Its presentation is variable and difficult to treat. The aim of our study was to investigate the impact of chronic anal pain after SH and whether tailored therapy was likely to achieve a favorable outcome. METHODS: We retrospectively analyzed 31 consecutive patients with chronic anal pain who had undergone SH in other hospitals and were referred to our institutions. Depending on the type of pain, unrelated (at rest) or related to defecation, two groups of patients were identified. Moreover, the mean distance of the staple line from the anal verge was calculated in both groups. Treatments included: topical nifedipine, local anesthetic and steroid infiltration, removal of retained staples, anal dilation, and scar excision with mucosal suturing. A visual analog scale (VAS) was used to compare pain at baseline, postoperatively, and in the follow-up. This mean difference of the VAS score between stages was always used as the main outcome measure, depending on the type of presentation, type of pain, and type of treatment. Treatment response was defined as a 50 % decrease of VAS from baseline. RESULTS: There were 22 males and 9 females. The overall median age was 43 years (range 21-62 years). On digital examination and proctoscopy, 15 (48 %) patients had inflammatory changes, 19 (61 %) patients had staple retention, 8 (26 %) patients had anorectal stenosis, and 30 (97 %) patients had scar tissue. All patients had one or more of the following treatments listed from the least to most invasive: topical nifedipine in 12 (39 %) patients, anal dilation in 6 (19 %) patients, anesthetic and steroid infiltration in 18 (58 %) patients, removal of staples in 10 (32 %) patients, and scar excision in 18 (58 %) patients. The mean VAS score at baseline was 6.100, ± 1.953 SD, which dropped significantly after treatment to 1.733, ± 1.658 SD (p < 0.001) and remained low at follow-up (1.741 ± SD 1.251; p < 0.743). In patients with pain at rest (n = 20, 65 %), the symptoms improved in 19 (95 %) patients, while the VAS score decreased from 5.552 ± 2.115 SD to 1.457 ± 1.440 SD (95 % CI 3.217-4.964; p < 0.001). In patients with post-evacuation pain (n = 11, 35 %), the symptoms improved in 11 (100 %) patients, while the VAS score decreased from 6.429 ± 1.835 SD to 1.891 ± 1.792 SD (95 % CI 3.784-5.269; p < 0.001). Rating of response based on presentation was 90.0 % (0.9/10) after treatment of staple retention, which led to a significant decrease in the mean VAS score from 6.304 ± 1.845 SD to 1.782 ± 1.731 SD (95 % CI 3.859-5.185; p < 0.001). Anal stenosis was successfully treated in 100.0 % (n = 8/8) of cases with the mean VAS score dropping from 6.500 ± 1.309 SD to 2.125 ± 1.808 SD (95 % CI 2.831-5.919; p < 0.001). Anal inflammation improved in 60.0 % (n = 9/15) of patients and the mean VAS score dropped from 6.006 ± 2.138 SD to 1.542 ± 1.457 SD (95 % CI 3.217-4.964; p < 0.001). The response after scar tissue treatment was 94 % (n = 17/18) of patients with a mean VAS decreasing from 6.117 ± 2.006 SD to 1.712 ± 1.697 SD (95 % CI 3.812-4.974; p < 0.001). Success for topical nifedipine was between 13 and 25 % of patients depending on the clinical presentation. Anal dilation was successful in 75 % of patients, while Anesthetic and steroid infiltration in 23-54 % of patients depending on the clinical presentation. Staple removal was successful in 77 % of patients, and scar excision with mucosal suturing in 94 % of patients. CONCLUSIONS: Our retrospective study suggests that most patients with chronic anal pain after SH may be cured with treatment by applying a stepwise approach from the least to the most invasive treatment.


Assuntos
Dor Crônica/terapia , Hemorroidectomia/efeitos adversos , Hemorroidas/cirurgia , Dor Pós-Operatória/terapia , Suturas/efeitos adversos , Adulto , Dor Crônica/etiologia , Feminino , Seguimentos , Hemorroidectomia/métodos , Humanos , Masculino , Pessoa de Meia-Idade , Medição da Dor , Dor Pós-Operatória/etiologia , Estudos Retrospectivos , Resultado do Tratamento
3.
J Biol Regul Homeost Agents ; 28(3): 507-13, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25316138

RESUMO

The pulmonary fibrosis extent in systemic sclerosis (SSc) has a prognostic value. Chest Computed Tomography (CT) is the gold standard to detect an interstitial lung disease (ILD). Semi-quantitative scores and quantitative methods can estimate the ILD. The first ones have a considerable inter-intraobserver variability, while quantitative scores, based on distribution of lung attenuation parameters (also called CT indexes), can be obtained through expensive and not so user-friendly software. The aim of this work is to investigate whether a DICOM-viewer open-source software (OsiriX) can obtain CT indexes correlating with semi-quantitative scores. Sixty-three chest CTs of ILD-SSc patients were assessed with two semi-quantitative methods (visual extent and limited/extensive ILD grading) and then blindly processed with OsiriX to obtain the distribution parameters of lung attenuation (kurtosis, skewness and mean). Semiquantitative assessment and CT indexes were compared through the Spearman rank test and Mann-Whitney test. All CT indexes showed a statistically significant correlation of moderate degree with the visual extent semi-quantitative assessment (p-value less than 0.05). Skewness was the lung attenuation distribution parameter with the strongest correlation (r =-0.378, p-value = 0.0023). Moreover, CT indexes of patients with an extensive and limited disease were statistically different (p less than 0.01). CT indexes correlating with a radiological semi-quantitative ILD assessment can be obtained through OsiriX. CT indexes can be considered very helpful to discriminate patients with extensive and limited ILD.


Assuntos
Processamento de Imagem Assistida por Computador/métodos , Doenças Pulmonares Intersticiais/diagnóstico por imagem , Escleroderma Sistêmico/diagnóstico por imagem , Software , Tomografia Computadorizada por Raios X/métodos , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
4.
Psychol Health Med ; 17(2): 207-12, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-21777093

RESUMO

The cognitive functioning is included in the concept of quality of life. Many times well-being remains incomplete because of cognitive difficulties, that people are not always able to properly recognize and explain. Nonetheless, only few instruments, specifically thought for non-clinical neurologic populations, are available to measure them. The present study is an attempt at providing a self-report instrument--cognitive functioning self-assessment scale (CFSS)--to measure the individual cognitive functioning in general population. The CFSS is itemized into18 questions to which participants answer on a five-point scale. Two hundred and eighty-two patients in a General Practitioner study have filled-in the CFSS together with a clinical and socio-demographic data form. Explorative factor analysis, using principal component analysis, suggests the consideration of the CFSS as one-dimensional; internal reliability = 0.856. Non-parametric tests have shown that women report a worse cognitive functioning than men, while no differences emerged in relation to age, manual prevalence, presence of an illness or being in pharmacological treatment. Although further verifications are necessary, the CFSS seems to be a promising self-report cognitive functioning measure.


Assuntos
Cognição/fisiologia , Psicometria , Qualidade de Vida , Autorrelato/normas , Autoavaliação (Psicologia) , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Análise Fatorial , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Análise de Componente Principal , Estatísticas não Paramétricas , Adulto Jovem
5.
Drugs Today (Barc) ; 57(9): 543-550, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34586102

RESUMO

Rheumatoid arthritis (RA) is a chronic autoimmune disease characterized by joint inflammation and progressive disability when inflammation cannot be sufficiently controlled. Despite treatment with conventional synthetic disease-modifying antirheumatic drugs (csDMARDs) and biological DMARDs (bDMARDs), up to 30% of RA patients do not reach or fail to maintain a good response over time. The recent introduction of Janus kinase inhibitors (JAKis) has widened the rheumatologist's armamentarium. Filgotinib, a selective JAK1 inhibitor, has been approved by the European Medicines Agency (EMA) for treatment of RA. Phase II and III studies highlighted filgotinib safety and efficacy in RA patients naive to DMARDs or with inadequate response to csDMARDs and bDMARDs. Filgotinib is administered orally at 200 mg every day. For patients older than 75 years or with moderate to severe renal impairment, a dose of filgotinib 100 mg every day is recommended.


Assuntos
Antirreumáticos , Artrite Reumatoide , Antirreumáticos/efeitos adversos , Artrite Reumatoide/tratamento farmacológico , Humanos , Piridinas/uso terapêutico , Triazóis/uso terapêutico
6.
Int J Law Psychiatry ; 68: 101455, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32033688

RESUMO

Understudied is psychopathy in females, particularly socially dangerous NGRI females, where the construct could be of forensic, clinical and criminologic significance. Italy's recent transformation of its mental health system created the context for studying such a population on a national level. Throughout the twentieth century until their closure in 2015, offenders found to be not guilty by reason of insanity (NGRI) and socially dangerous were placed in one of the the six high security hospitals in Italy (OPGs). Only one hospital, the Castiglione delle Stiviere maximum security hospital (OPG) in North Italy, treated female offenders, who came from all parts of Italy. The authors studied 66 of all 86 women in Castiglione delle Stiviere OPG. The aims of this study were to identify the prevalence of psychopathy in NGRI female offenders and eventually to identify any phenotypic gender-specific features of psychopathy. The SCID I and II interviews and other tests (MMPI-2, MCMI-III, R-Bans) were administered to all the women. Clinical historical information was obtained. Finally for all women who consented to participate in the study, the researchers administered the PCL-R version validated for the Italian population. The final sample consisted of 66 women, who were deemed NGRI and socially dangerous. Here the authors present the final results as well as limitations of the research.


Assuntos
Defesa por Insanidade , Fenótipo , Prisioneiros/psicologia , Mulheres/psicologia , Adulto , Idoso , Transtorno da Personalidade Borderline/diagnóstico , Comportamento Perigoso , Feminino , Hospitais Psiquiátricos , Humanos , Itália , Pessoa de Meia-Idade , Determinação da Personalidade , Testes de Personalidade , Prevalência , Psicopatologia/estatística & dados numéricos
7.
J Cell Biol ; 145(5): 979-91, 1999 May 31.
Artigo em Inglês | MEDLINE | ID: mdl-10352016

RESUMO

The mitotic checkpoint blocks cell cycle progression before anaphase in case of mistakes in the alignment of chromosomes on the mitotic spindle. In budding yeast, the Mad1, 2, 3, and Bub1, 2, 3 proteins mediate this arrest. Vertebrate homologues of Mad1, 2, 3, and Bub1, 3 bind to unattached kinetochores and prevent progression through mitosis by inhibiting Cdc20/APC-mediated proteolysis of anaphase inhibitors, like Pds1 and B-type cyclins. We investigated the role of Bub2 in budding yeast mitotic checkpoint. The following observations indicate that Bub2 and Mad1, 2 probably activate the checkpoint via different pathways: (a) unlike the other Mad and Bub proteins, Bub2 localizes at the spindle pole body (SPB) throughout the cell cycle; (b) the effect of concomitant lack of Mad1 or Mad2 and Bub2 is additive, since nocodazole-treated mad1 bub2 and mad2 bub2 double mutants rereplicate DNA more rapidly and efficiently than either single mutant; (c) cell cycle progression of bub2 cells in the presence of nocodazole requires the Cdc26 APC subunit, which, conversely, is not required for mad2 cells in the same conditions. Altogether, our data suggest that activation of the mitotic checkpoint blocks progression through mitosis by independent and partially redundant mechanisms.


Assuntos
Proteínas de Ligação ao Cálcio/fisiologia , Proteínas de Transporte , Proteínas de Ciclo Celular , Proteínas Fúngicas/fisiologia , Mitose/fisiologia , Proteínas de Saccharomyces cerevisiae , Saccharomyces cerevisiae/fisiologia , Transdução de Sinais , Ciclinas/fisiologia , Proteínas Mad2 , Proteínas Nucleares , Saccharomyces cerevisiae/citologia
8.
J Cell Biol ; 144(5): 823-37, 1999 Mar 08.
Artigo em Inglês | MEDLINE | ID: mdl-10085284

RESUMO

p27(BBP/eIF6) is an evolutionarily conserved protein that was originally identified as p27(BBP), an interactor of the cytoplasmic domain of integrin beta4 and, independently, as the putative translation initiation factor eIF6. To establish the in vivo function of p27(BBP/eIF6), its topographical distribution was investigated in mammalian cells and the effects of disrupting the corresponding gene was studied in the budding yeast, Saccharomyces cerevisiae. In epithelial cells containing beta4 integrin, p27(BBP/eIF6) is present in the cytoplasm and enriched at hemidesmosomes with a pattern similar to that of beta4 integrin. Surprisingly, in the absence and in the presence of the beta4 integrin subunit, p27(BBP/eIF6) is in the nucleolus and associated with the nuclear matrix. Deletion of the IIH S. cerevisiae gene, encoding the yeast p27(BBP/eIF6) homologue, is lethal, and depletion of the corresponding gene product is associated with a dramatic decrease of the level of free ribosomal 60S subunit. Furthermore, human p27(BBP/eIF6) can rescue the lethal effect of the iihDelta yeast mutation. The data obtained in vivo suggest an evolutionarily conserved function of p27(BBP/eIF6) in ribosome biogenesis or assembly rather than in translation. A further function related to the beta4 integrin subunit may have evolved specifically in higher eukaryotic cells.


Assuntos
Proteínas de Transporte/fisiologia , Proteínas de Filamentos Intermediários/fisiologia , Proteínas Nucleares/fisiologia , Fosfoproteínas , Ribossomos , Proteínas de Saccharomyces cerevisiae , Sequência de Aminoácidos , Antígenos Nucleares , Sequência de Bases , Proteínas de Transporte/genética , Proteínas de Transporte/metabolismo , Nucléolo Celular/metabolismo , Primers do DNA , Fatores de Iniciação em Eucariotos , Técnica Indireta de Fluorescência para Anticorpo , Humanos , Imuno-Histoquímica , Proteínas de Filamentos Intermediários/genética , Proteínas de Filamentos Intermediários/metabolismo , Microscopia Eletrônica , Mitose , Dados de Sequência Molecular , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Proteínas Ribossômicas , Saccharomyces cerevisiae/genética , Homologia de Sequência de Aminoácidos
9.
Transfus Apher Sci ; 40(2): 115-8, 2009 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-19237316

RESUMO

A 3-year-old boy present with a severe autoimmune haemolytic anaemia, triggered by IgG-class auto-antibodies, with hemoglobin levels decreased to 2, 1 gr/dL. A combined immunosuppressive regimen was begun together with multiple plasma-exchanges and transfusions which sustained the cardio-vascular balance until the specific therapy became effective.


Assuntos
Anemia Hemolítica Autoimune/terapia , Imunossupressores/uso terapêutico , Troca Plasmática , Anemia Hemolítica Autoimune/tratamento farmacológico , Anticorpos Monoclonais/uso terapêutico , Anticorpos Monoclonais Murinos , Pré-Escolar , Terapia Combinada , Ciclofosfamida/uso terapêutico , Humanos , Masculino , Metilprednisolona/uso terapêutico , Rituximab
10.
Trends Biochem Sci ; 22(11): 424-7, 1997 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-9397683

RESUMO

The highly conserved DNA polymerase alpha-primase complex (pol-prism) is the only eukaryotic DNA polymerase that can initiate DNA synthesis de novo. It is required both for the initiation of DNA replication at chromosomal origins and for the discontinuous synthesis of Okazaki fragments on the lagging strand of the replication fork. The dual role of pol-prim makes it a likely target for mechanisms that control cell-cycle S-phase entry and progression.


Assuntos
Ciclo Celular , Dano ao DNA , DNA Primase/metabolismo , Replicação do DNA , DNA Polimerase Dirigida por DNA/metabolismo , Animais , Humanos
11.
Exp Gerontol ; 43(2): 61-5, 2008 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-17870272

RESUMO

Recent observations indicate that immunosenescence is not accompanied by an unavoidable and progressive deterioration of the immune function, but is rather the result of a remodeling where some functions are reduced, others remain unchanged or even increased. In addition, it appears that the ancestral/innate compartment of the immune system is relatively preserved during aging in comparison to the more recent and sophisticated adaptive compartment that exhibit more profound modifications. The T-cell branch displays an age-dependent decline of the absolute number of total T-cells (CD3+), involving both CD4+ and CD8+ subsets, accompanied by an increase of NK cells with well-preserved cytotoxic function and by a reduction of B-cells. One of the main characteristics of the immune system during aging is a progressive, age-dependent decline of the virgin T-cells (CD95-), which is particularly profound at the level of the CD8+ subpopulation of the oldest old subjects. The progressive exhaustion of this important T-cell subpopulation dedicated primarily to the defense against new antigenic challenges (viral, neoplastic, bacterial ones), could be a consequence of both the thymic involution and the lifelong chronic antigenic stimulation. The immune function of the elderly, is therefore weakened by the exhaustion of CD95- virgin cells that are replaced by large clonal expansions of CD28- T-cells. The origin of CD28- cells has not been completely clarified yet, but it is assumed that they represent cells in the phase of replicative senescence characterized by shortening telomers and reduced proliferative capacity. A major characteristic of the immune system during aging is the up-regulation of the inflammatory responses which appears to be detrimental for longevity. In this regard, we have recently observed a progressive age-dependent increase of type 1(IL-2, IFN-gamma, TNF-alpha) and type 2 (IL-4, IL-6, IL-10) positive CD8+ T-cells; in particular, type 1 cytokine-positive cells significantly increased, with age, in all CD8+ subsets particularly among effector/cytotoxic and memory cells. A major force able to drive a chronic pro-inflammatory state during aging may be represented by persistent viral infections by EBV and CMV. Therefore, we have determined the frequency and the absolute number of viral antigen-specific CD8+ T-cells in subjects older than 85 years, who were serologically positive for CMV or EBV. In the majority of these subjects we detected the presence of T lymphocytes positive for epitopes of CMV or EBV. In all subjects the absolute number of CMV-positive CD8+ cells outnumbered that of EBV-positive ones. In addition, the majority of CMV+ T cells were included within the CD28- subpopulation, while EBV+ T cells belonged mainly to the CD28+ subset. These data indicate that the chronic antigenic stimulation induced by persistent viral infections during aging bring about important modifications among CD8+ subsets, which are particularly evident in the presence of CMV persistence. The age-dependent expansions of CD8+CD28- T-cells, mostly positive for pro-inflammatory cytokines and including the majority of CMV-epitope-specific cells, underlines the importance of chronic antigenic stimulation in the pathogenesis of the main immunological alterations of aging and may favour the appearance of several pathologies (arteriosclerosis, dementia, osteoporosis, cancer) all of which share an inflammatory pathogenesis.


Assuntos
Sistema Imunitário/fisiologia , Longevidade/imunologia , Idoso de 80 Anos ou mais , Linfócitos T CD8-Positivos/imunologia , Citocinas/fisiologia , Feminino , Humanos , Memória Imunológica , Inflamação , Ativação Linfocitária , Masculino
12.
Mol Cell Biol ; 14(12): 7884-90, 1994 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-7969128

RESUMO

Replication factor A (RF-A) is a heterotrimeric single-stranded-DNA-binding protein which is conserved in all eukaryotes. Since the availability of conditional mutants is an essential step to define functions and interactions of RF-A in vivo, we have produced and characterized mutations in the RFA1 gene, encoding the p70 subunit of the complex in Saccharomyces cerevisiae. This analysis provides the first in vivo evidence that RF-A function is critical not only for DNA replication but also for efficient DNA repair and recombination. Moreover, genetic evidence indicate that p70 interacts both with the DNA polymerase alpha-primase complex and with DNA polymerase delta.


Assuntos
Reparo do DNA , Replicação do DNA , Proteínas de Ligação a DNA/genética , Recombinação Genética , Saccharomyces cerevisiae/genética , Análise Mutacional de DNA , DNA Polimerase II/metabolismo , DNA Polimerase III , DNA Primase , DNA Fúngico/genética , DNA Polimerase Dirigida por DNA/metabolismo , Proteínas Fúngicas/genética , RNA Nucleotidiltransferases/metabolismo , Proteína de Replicação A
13.
Mol Cell Biol ; 15(2): 883-91, 1995 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-7823954

RESUMO

The yeast DNA polymerase alpha-primase B subunit functions in initiation of DNA replication. This protein is present in two forms, of 86 and 91 kDa, and the p91 polypeptide results from cell cycle-regulated phosphorylation of p86. The B subunit present in G1 arises by dephosphorylation of p91 while cells are exiting from mitosis, becomes phosphorylated in early S phase, and is competent and sufficient to initiate DNA replication. The B subunit transiently synthesized as a consequence of periodic transcription of the POL12 gene is phosphorylated no earlier than G2. Phosphorylation of the B subunit does not require execution of the CDC7-dependent step and ongoing DNA synthesis. We suggest that posttranslational modifications of the B subunit might modulate the role of DNA polymerase alpha-primase in DNA replication.


Assuntos
Ciclo Celular/fisiologia , RNA Nucleotidiltransferases/metabolismo , Saccharomyces cerevisiae/citologia , Saccharomyces cerevisiae/enzimologia , Fosfatase Ácida , Western Blotting , DNA Primase , Replicação do DNA , Fase G1 , Expressão Gênica , Genótipo , Cinética , Substâncias Macromoleculares , Mutagênese , Fosforilação , Plasmídeos , Regiões Promotoras Genéticas , Saccharomyces cerevisiae/genética , Solanum tuberosum/enzimologia , Fatores de Tempo
14.
Mol Cell Biol ; 16(7): 3235-44, 1996 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-8668138

RESUMO

The catalytic DNA primase subunit of the DNA polymerase alpha-primase complex is encoded by the essential PRI1 gene in Saccharomyces cerevisiae. To identify factors that functionally interact with yeast DNA primase in living cells, we developed a genetic screen for mutants that are lethal at the permissive temperature in a cold-sensitive pril-2 genetic background. Twenty-four recessive mutations belonging to seven complementation groups were identified. Some mutants showed additional phenotypes, such as increased sensitivity to UV irradiation, methyl methanesulfonate, and hydroxyurea, that were suggestive of defects in DNA repair and/or checkpoint mechanisms. We have cloned and characterized the gene of one complementation group, PIP3, whose product is necessary both for delaying entry into S phase or mitosis when cells are UV irradiated in G1 or G2 phase and for lowering the rate of ongoing DNA synthesis in the presence of methyl methanesulfonate. PIP3 turned out to be the MEC3 gene, previously identified as a component of the G2 DNA damage checkpoint. The finding that Mec3 is also required for the G1- and S-phase DNA damage checkpoints, together with the analysis of genetic interactions between a mec3 null allele and several conditional DNA replication mutations at the permissive temperature, suggests that Mec3 could be part of a mechanism coupling DNA replication with repair of DNA damage, and DNA primase might be involved in this process.


Assuntos
Proteínas de Ciclo Celular/metabolismo , Dano ao DNA , Replicação do DNA , Genes Fúngicos , RNA Nucleotidiltransferases/metabolismo , Proteínas de Saccharomyces cerevisiae , Saccharomyces cerevisiae/enzimologia , Saccharomyces cerevisiae/genética , Ciclo Celular/efeitos dos fármacos , Ciclo Celular/efeitos da radiação , Proteínas de Ciclo Celular/genética , DNA Primase , Relação Dose-Resposta à Radiação , Teste de Complementação Genética , Genótipo , Hidroxiureia/farmacologia , Metanossulfonato de Metila/farmacologia , Mitose , Mutagênese , Mutagênicos/farmacologia , RNA Nucleotidiltransferases/genética , Fase S , Saccharomyces cerevisiae/crescimento & desenvolvimento , Temperatura , Raios Ultravioleta
15.
Mol Cell Biol ; 9(7): 3081-7, 1989 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-2528682

RESUMO

DNA primase activity of the yeast DNA polymerase-primase complex is related to two polypeptides, p58 and p48. The reciprocal role of these protein species has not yet been clarified, although both participate in formation of the active center of the enzyme. The gene encoding the p58 subunit has been cloned by screening of a lambda gt11 yeast genomic DNA library, using specific anti-p58 antiserum. Antibodies that inhibited DNA primase activity could be purified by lysates of Escherichia coli cells infected with a recombinant bacteriophage containing the entire gene, which we designate PR12. The gene was found to be transcribed in a 1.7-kilobase mRNA whose level appeared to fluctuate during the mitotic cell cycle. Nucleotide sequence determination indicated that PR12 encodes a 528-amino-acid polypeptide with a calculated molecular weight of 62,262. The gene is unique in the haploid yeast genome, and its product is essential for cell viability, as has been shown for other components of the yeast DNA polymerase-primase complex.


Assuntos
Replicação do DNA , Genes Fúngicos , RNA Nucleotidiltransferases/genética , Saccharomyces cerevisiae/genética , Sequência de Aminoácidos , Bacteriófago lambda/genética , Sequência de Bases , Clonagem Molecular , DNA Primase , Sondas de DNA , DNA Fúngico/genética , Escherichia coli/genética , Regulação da Expressão Gênica , Immunoblotting , Dados de Sequência Molecular , Plasmídeos , RNA Nucleotidiltransferases/biossíntese , RNA Fúngico/biossíntese , RNA Fúngico/genética , RNA Mensageiro/biossíntese , RNA Mensageiro/genética , Mapeamento por Restrição , Saccharomyces cerevisiae/enzimologia
16.
Mol Cell Biol ; 14(2): 923-33, 1994 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-8289832

RESUMO

The four-subunit DNA polymerase alpha-primase complex is unique in its ability to synthesize DNA chains de novo, and some in vitro data suggest its involvement in initiation and elongation of chromosomal DNA replication, although direct in vivo evidence for a role in the initiation reaction is still lacking. The function of the B subunit of the complex is unknown, but the Saccharomyces cerevisiae POL12 gene, which encodes this protein, is essential for cell viability. We have produced different pol12 alleles by in vitro mutagenesis of the cloned gene. The in vivo analysis of our 18 pol12 alleles indicates that the conserved carboxy-terminal two-thirds of the protein contains regions that are essential for cell viability, while the more divergent NH2-terminal portion is partially dispensable. The characterization of the temperature-sensitive pol12-T9 mutant allele demonstrates that the B subunit is required for in vivo DNA synthesis and correct progression through S phase. Moreover, reciprocal shift experiments indicate that the POL12 gene product plays an essential role at the early stage of chromosomal DNA replication, before the hydroxyurea-sensitive step. A model for the role of the B subunit in initiation of DNA replication at an origin is presented.


Assuntos
Replicação do DNA , Genes Fúngicos , RNA Nucleotidiltransferases/metabolismo , Saccharomyces cerevisiae/enzimologia , Alelos , Sequência de Aminoácidos , Animais , Anticorpos Monoclonais , Western Blotting , Cromossomos Fúngicos/efeitos dos fármacos , DNA Primase , Homeostase , Humanos , Hidroxiureia/farmacologia , Cinética , Substâncias Macromoleculares , Camundongos , Camundongos Endogâmicos BALB C/imunologia , Modelos Genéticos , Dados de Sequência Molecular , Mutagênese Insercional , Mutagênese Sítio-Dirigida , RNA Nucleotidiltransferases/análise , RNA Nucleotidiltransferases/biossíntese , Saccharomyces cerevisiae/genética , Deleção de Sequência , Homologia de Sequência de Aminoácidos
17.
Mol Cell Biol ; 4(7): 1326-33, 1984 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-6095062

RESUMO

The role of cis- and trans-acting elements in the expression of HIS4 has been examined by using HIS4-lacZ fusions in which lacZ expression is dependent upon the HIS4 5' noncoding region. The cis-acting sequences involved in regulation were defined by studying the effects of the wild-type and various deletions and their revertants on regulation via the general control of amino acid biosynthesis. The role of trans-acting genes was analyzed by studying the regulation of the HIS4-lacZ fusions in strains carrying mutations in the GCN (AAS) or GCD (TRA) genes and in strains carrying the GCN genes on high-copy-number plasmids. These studies have led to the following conclusions. (i) HIS4 is positively regulated by the general control. (ii) At least one copy of the 5'TGACTC3' repeat at -136 is required in cis for this regulation. (iii) Both the GCN4 gene and at least one copy of the repeated sequence are required for expression at the repressed level. (iv) The open reading frames in the 5' noncoding region are not required in either cis or trans for the regulation of HIS4.


Assuntos
Genes Fúngicos , Genes Reguladores , Genes , Saccharomyces cerevisiae/genética , Deleção Cromossômica , Enzimas de Restrição do DNA , Mutação , Plasmídeos , Especificidade da Espécie , beta-Galactosidase/genética
18.
Mol Cell Biol ; 21(12): 3913-25, 2001 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-11359899

RESUMO

DNA damage checkpoints lead to the inhibition of cell cycle progression following DNA damage. The Saccharomyces cerevisiae Mec1 checkpoint protein, a phosphatidylinositol kinase-related protein, is required for transient cell cycle arrest in response to DNA damage or DNA replication defects. We show that mec1 kinase-deficient (mec1kd) mutants are indistinguishable from mec1Delta cells, indicating that the Mec1 conserved kinase domain is required for all known Mec1 functions, including cell viability and proper DNA damage response. Mec1kd variants maintain the ability to physically interact with both Ddc2 and wild-type Mec1 and cause dominant checkpoint defects when overproduced in MEC1 cells, impairing the ability of cells to slow down S phase entry and progression after DNA damage in G(1) or during S phase. Conversely, an excess of Mec1kd in MEC1 cells does not abrogate the G(2)/M checkpoint, suggesting that Mec1 functions required for response to aberrant DNA structures during specific cell cycle stages can be separable. In agreement with this hypothesis, we describe two new hypomorphic mec1 mutants that are completely defective in the G(1)/S and intra-S DNA damage checkpoints but properly delay nuclear division after UV irradiation in G(2). The finding that these mutants, although indistinguishable from mec1Delta cells with respect to the ability to replicate a damaged DNA template, do not lose viability after UV light and methyl methanesulfonate treatment suggests that checkpoint impairments do not necessarily result in hypersensitivity to DNA-damaging agents.


Assuntos
Dano ao DNA , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Genes Fúngicos , Mutação , Proteínas de Saccharomyces cerevisiae , Alelos , Sequência de Aminoácidos , Sequência de Bases , Ciclo Celular/efeitos da radiação , Sequência Conservada , Primers do DNA/genética , Reparo do DNA , Replicação do DNA , DNA Fúngico/genética , DNA Fúngico/metabolismo , Proteínas Fúngicas/química , Peptídeos e Proteínas de Sinalização Intracelular , Dados de Sequência Molecular , Mutagênicos/toxicidade , Fosfatidilinositol 3-Quinases/química , Fosfatidilinositol 3-Quinases/genética , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Serina-Treonina Quinases , Estrutura Terciária de Proteína , Saccharomyces cerevisiae/citologia , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/efeitos da radiação , Homologia de Sequência de Aminoácidos , Raios Ultravioleta
19.
Rev Sci Instrum ; 78(1): 013105, 2007 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-17503905

RESUMO

We present a control system, which allows an automatic optimization of the pulse train stability in a mode-locked laser cavity. In order to obtain real-time corrections, we chose a closed loop approach. The control variable is the cavity length, mechanically adjusted by gear system acting on the rear cavity mirror, and the controlled variable is the envelope modulation of the mode-locked pulse train. Such automatic control system maintains the amplitude of the mode-locking pulse train stable within a few percent rms during the working time of the laser. Full implementation of the system on an Nd:yttrium lithium fluoride actively mode-locked laser is presented.


Assuntos
Fluoretos , Lasers , Lítio , Neodímio , Ítrio , Fatores de Tempo
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