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1.
J Infect Chemother ; 27(8): 1162-1168, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-33781690

RESUMO

INTRODUCTION: Debridement, antibiotics and implant retention (DAIR) is an attractive treatment option for prosthetic joint infections (PJIs). However, reported success rates and predictors of DAIR failure vary widely. The primary aim of this study is to report the outcome of DAIR in patients with hip and knee PJIs receiving short course of antibiotic therapy. The secondary aim is to identify risk factors for DAIR failure. METHODS: We performed a retrospective analysis of prospectively collected data of all hip and knee PJIs consecutively diagnosed at Quadrante Orthopedic Center, an Italian orthopedic hospital highly specialized in prosthetic surgery, from January 1, 2013 to January 1, 2019, and we analyzed those treated with DAIR. RESULTS: Forty-seven PJIs occurred after 5102 arthroplasty procedures. Twenty-one patients (45%) aged 71 years were treated with DAIR for hip (62%) and knee (38%) PJIs. These were classified as early PJIs in 76% cases, delayed in 19% and late in 5%. Median time from PJI-related symptoms onset to implant revision surgery was 12 days (IQR, 7-20 days). The median duration of antibiotic treatment after surgery was 63 days (IQR, 53-84 days). Sixteen (76%) patients were cured after a median follow-up of 2197 days (IQR, 815-2342 days), while 5 (24%) experienced failure. At multivariate analysis, delayed/late PJIs were significantly associated with failure (OR = 12.51; 95% CI 1.21-129.63, p = 0.03). CONCLUSIONS: DAIR represents an effective strategy for the treatment of early PJIs in spite of short course of antibiotic therapy.


Assuntos
Artrite Infecciosa , Infecções Relacionadas à Prótese , Antibacterianos/uso terapêutico , Artrite Infecciosa/tratamento farmacológico , Artrite Infecciosa/cirurgia , Desbridamento , Humanos , Infecções Relacionadas à Prótese/tratamento farmacológico , Estudos Retrospectivos , Resultado do Tratamento
2.
J Infect Chemother ; 24(12): 990-994, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30098915

RESUMO

Visceral leishmaniasis has been recognized as an opportunistic infection affecting people with cellular-immunity impairment, including hematopoietic cell transplantation (HCT) recipients. We describe the case of a young Italian man with Hodgkin lymphoma, who developed visceral leishmaniasis after multiple lines of chemotherapy and allogenic HCT. Literature review of visceral leishmaniasis in HCT recipients was also performed. Eleven patients (median age 50 years, 9 male) developed visceral leishmaniasis after allogenic (n = 9) and autologous (n = 2) HCT. Most of them presented with fever and pancytopenia. Bone marrow examination was the main diagnostic technique; liposomal amphotericin B was the treatment of choice. Four out of eight patients (for whom data are available) experienced visceral leishmaniasis relapse. Visceral leishmaniasis in HCT recipients is a rare event that should be suspected in patients with persistent fever, pancytopenia and possible exposure to Leishmania spp., remembering that - as well as South-East Asia, East Africa and South America - it is endemic in several European regions.


Assuntos
Anticorpos Antiprotozoários/imunologia , Transplante de Células-Tronco Hematopoéticas/efeitos adversos , Doença de Hodgkin/terapia , Leishmania/imunologia , Leishmaniose Visceral/parasitologia , Infecções Oportunistas/parasitologia , Adulto , Anfotericina B/administração & dosagem , Anfotericina B/uso terapêutico , Anticorpos Antiprotozoários/sangue , Antineoplásicos/uso terapêutico , Antiprotozoários/administração & dosagem , Antiprotozoários/uso terapêutico , Exame de Medula Óssea , Evolução Fatal , Feminino , Doença de Hodgkin/tratamento farmacológico , Humanos , Leishmania/genética , Leishmania/isolamento & purificação , Leishmaniose Visceral/sangue , Leishmaniose Visceral/diagnóstico , Leishmaniose Visceral/tratamento farmacológico , Masculino , Pessoa de Meia-Idade , Infecções Oportunistas/sangue , Infecções Oportunistas/diagnóstico , Infecções Oportunistas/tratamento farmacológico , Recidiva
3.
J Antimicrob Chemother ; 71(3): 739-50, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26679249

RESUMO

OBJECTIVES: This study aims to evaluate the reliability and clinical utility of NS3 sequencing in hepatitis C virus (HCV) 1-infected patients who were candidates to start a PI-containing regimen. METHODS: NS3 protease sequencing was performed by in-house-developed HCV-1 subtype-specific protocols. Phylogenetic analysis was used to test sequencing reliability and concordance with previous genotype/subtype assignment by commercial genotyping assays. RESULTS: Five hundred and sixty-seven HCV plasma samples with quantifiable HCV-RNA from 326 HCV-infected patients were collected between 2011 and 2014. Overall, the success rate of NS3 sequencing was 88.9%. The success rate between the two subtype protocols (HCV-1a/HCV-1b) was similarly high for samples with HCV-RNA >3 log IU/mL (>92% success rate), while it was slightly lower for HCV-1a samples with HCV-RNA ≤3 log IU/mL compared with HCV-1b samples. Phylogenetic analysis confirmed the genotype/subtype given by commercial genotyping assays in 92.9% (303/326) of cases analysed. In the remaining 23 cases (7.1%), 1 was HCV-1g (previously defined as subtype 1a), 1 was HCV-4d (previously defined as genotype 1b) and 1 was HCV-1b (previously defined as genotype 2a/2c). In the other cases, NS3 sequencing precisely resolved the either previous undetermined/discordant subtype 1 or double genotype/subtype assignment by commercial genotyping assays. Resistance-associated variants (RAVs) to PI were detected in 31.0% of samples. This prevalence changed according to PI experience (17.1% in PI-naive patients versus 79.2% in boceprevir/telaprevir/simeprevir-failing patients). Among 96 patients with available virological outcome following boceprevir/telaprevir treatment, a trend of association between baseline NS3 RAVs and virological failure was observed (particularly for HCV-1a-infected patients: 3/21 failing patients versus 0/22 achieving sustained virological response; P = 0.11). CONCLUSIONS: HCV-NS3 sequencing provides reliable results and at the same time gives two clinically relevant pieces of information: a correct subtype/genotype assignment and the detection of variants that may interfere with the efficacy of PI.


Assuntos
Farmacorresistência Viral , Técnicas de Genotipagem/métodos , Hepacivirus/classificação , Hepacivirus/efeitos dos fármacos , Hepatite C/virologia , Mutação , Proteínas não Estruturais Virais/genética , Genótipo , Hepacivirus/genética , Hepacivirus/isolamento & purificação , Humanos , RNA Viral/genética , Estudos Retrospectivos , Análise de Sequência de DNA
4.
J Prev Med Hyg ; 56(1): E28-32, 2015 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-26789829

RESUMO

HIV-infected patients are at increased risk for both vaccine-preventable diseases and their complications, with mortality rates higher than in non-HIV-infected individuals. Consequently, international guidelines generally recommend inactivated vaccines in HIV-patients, even if HIV-related immunodeficiency may impair efficacy; live vaccines are usually not recommended in these patients because of safety concerns. The aim of this short article is to review current knowledge about both efficacy and safety of vaccines in HIV-infected individuals.

5.
J Prev Med Hyg ; 54(2): 83-6, 2013 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-24396987

RESUMO

INTRODUCTION: Recent studies have demonstrated the role of the interleukin 28B (IL28B) polymorphisms in predicting treatment induced and spontaneous clearance from Hepatitis C virus (HCV) infection, suggesting the possibility of tailored therapy in HCV infected patients. Genome-wide association studies have shown that single nucleotide polymorphisms (SNPs) near IL 28B gene on chromosome 19 are strong predictors of sustained virologic response (SVR) to pegylated interferon and ribavirin. This study was aimed at analyzing the co-prevalence of two common and clinically significant SNPs in a cohort of Ligurian patients. METHODS: Two SNPs (rs12979860, rs8099917) were genotyped in the IL28B locus from 175 DNA samples collected from HCV-infected consecutive patients in a Laboratory of Liguria Region, northern Italy. A real-time polymerase chain reaction in a Corbett Research Termocycler (Rotor Gene 3000A) by fluorescent probes (Fast Set IL 28B, Arrow Diagnostics) was used for the detection, according to the manufacturer's instructions. RESULTS: Carriers of rs12979860CT genotype predominated (87/175, 50%), homozygotes for allele C were 68/175 (39%) and the remaining were homozygotes for IFN-resistant allele T (11%). As for the rs8099917 SNP, genotypes were thus distributed: 96/175 (55%) carried the rs8099917 TT genotype, whereas 70/175 (40%) and 9/175 (5%), were heterozygotes or homozygotes for the G allele. The variants rs12979860CC and rs8099917TT were found in 39% and 54% of overall patients with HCV genotype 1, respectively. The combined assessment of examined SNPs resulted in three most prevalent genotypes (rs12979860CC/rs8099917TT, rs12979860CT/rs8099917TG and rs12979860CT/rs8099917TT) with a frequency of 35%, 31% and 18%, respectively. DISCUSSION: Recent findings demonstrated that in carriers of rs12979860CT the determination of additional genotype of rs8099917 SNP could significantly improve the prediction of SVR. In our study cohort carriers of rs12979860CT represented 50% of all patients, who could take advantage with respect to SVR prediction by further determination of the rs8099917 SNP. The simultaneous genotyping of two IL28B SNPs should thus be recommended in HCV infected patients prior to treatment initiation.


Assuntos
Hepacivirus/genética , Hepatite C/genética , Interleucinas/genética , Polimorfismo de Nucleotídeo Único , População Branca/genética , Adulto , Idoso , Alelos , Feminino , Genótipo , Humanos , Interferons , Itália , Testes de Função Hepática , Masculino , Pessoa de Meia-Idade , Reação em Cadeia da Polimerase em Tempo Real
6.
Spinal Cord ; 49(8): 880-5, 2011 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-21445081

RESUMO

STUDY DESIGN: Multi-center, prospective, cohort study. OBJECTIVES: To assess the validity and reliability of the Spinal Cord Independence Measure (SCIM III) in measuring functional ability in persons with spinal cord injury (SCI). SETTING: Inpatient rehabilitation hospitals in the United States (US). METHODS: Functional ability was measured with the SCIM III during the first week of admittance into inpatient acute rehabilitation and within one week of discharge from the same rehabilitation program. Motor and sensory neurologic impairment was measured with the American Spinal Injury Association Impairment Scale. The Functional Independence Measure (FIM), the default functional measure currently used in most US hospitals, was used as a comparison standard for the SCIM III. Statistical analyses were used to test the validity and reliability of the SCIM III. RESULTS: Total agreement between raters was above 70% on most SCIM III tasks and all κ-coefficients were statistically significant (P<0.001). The coefficients of Pearson correlation between the paired raters were above 0.81 and intraclass correlation coefficients were above 0.81. Cronbach's-α was above 0.7, with the exception of the respiration task. The coefficient of Pearson correlation between the FIM and SCIM III was 0.8 (P<0.001). For the respiration and sphincter management subscale, the SCIM III was more responsive to change, than the FIM (P<0.0001). CONCLUSION: Overall, the SCIM III is a reliable and valid measure of functional change in SCI. However, improved scoring instructions and a few modifications to the scoring categories may reduce variability between raters and enhance clinical utility.


Assuntos
Avaliação da Deficiência , Traumatismos da Medula Espinal/diagnóstico , Traumatismos da Medula Espinal/epidemiologia , Atividades Cotidianas , Adolescente , Adulto , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Reprodutibilidade dos Testes , Traumatismos da Medula Espinal/reabilitação , Estatística como Assunto , Estados Unidos/epidemiologia , Adulto Jovem
7.
Intern Emerg Med ; 15(4): 645-654, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-31786751

RESUMO

Prevalence and clinical impact of viral respiratory tract infections (VRTIs) on community-acquired pneumonia (CAP) has not been well defined so far. The aims of this study were to investigate the prevalence and the clinical impact of VRTIs in patients with CAP. Prospective study involving adult patients consecutively admitted at medical wards for CAP and tested for VRTIs by real-time PCR on pharyngeal swab. Patients' features were evaluated with regard to the presence of VRTI and aetiology of CAP. Clinical failure was a composite endpoint defined by worsening of signs and symptoms requiring escalation of antibiotic treatment or ICU admission or death within 30 days. 91 patients were enrolled, mean age 65.7 ± 10.6 years, 50.5% female. 62 patients (68.2%) had no viral co-infection while in 29 patients (31.8%) a VRTI was detected; influenza virus was the most frequently identified (41.9%). The two groups were similar in terms of baseline features. In presence of a VRTI, pneumonia severity index (PSI) was more frequently higher than 91 and patients had received less frequently pre-admission antibiotic therapy (adjusted OR 2.689, 95% CI 1.017-7.111, p = 0.046; adjusted OR 0.143, 95% CI 0.030-0.670, p = 0.014). Clinical failure and antibiotic therapy duration were similar with regards to the presence of VRTI and the aetiology of CAP. VRTIs can be detected in almost a third of adults with CAP; influenza virus is the most relevant one. VRTI was associated with higher PSI at admission, but it does not affect patients' outcome.


Assuntos
Infecções Comunitárias Adquiridas/microbiologia , Pneumonia/microbiologia , Infecções Respiratórias/virologia , Idoso , Coinfecção , Infecções Comunitárias Adquiridas/epidemiologia , Feminino , Hospitalização , Humanos , Itália/epidemiologia , Masculino , Pneumonia/epidemiologia , Prevalência , Estudos Prospectivos , Infecções Respiratórias/epidemiologia
8.
J Biotechnol ; 109(1-2): 123-30, 2004 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-15063620

RESUMO

Superoxide dismutases are ubiquitous enzymes which play an important role in protecting cells against oxidative damage and which have also been shown to contribute to the pathogenicity of many bacterial species. Here we demonstrate that Vibrio cholerae, the causative agent of cholerae, expresses an active periplasmic Cu,Zn superoxide dismutase. Moreover, we have set up an expression system yielding large amounts of V. cholerae recombinant Cu,Zn superoxide dismutase in the periplasm of Escherichia coli and a procedure to obtain the enzyme in a highly purified form. Unlike the bovine enzyme, V. cholerae Cu,Zn superoxide dismutase has been proved to be highly resistant to inactivation by hydrogen peroxide. This property, which appears to be common to other bacterial enzymes of this class, might improve the ability of Cu,Zn superoxide dismutase to protect bacteria against the reactive oxygen species produced by phagocytes.


Assuntos
Superóxido Dismutase/genética , Vibrio cholerae/genética , Clonagem Molecular , Ditiocarb/farmacologia , Inibidores Enzimáticos/farmacologia , Escherichia coli/genética , Expressão Gênica , Dados de Sequência Molecular , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/isolamento & purificação , Alinhamento de Sequência , Análise de Sequência de Proteína , Superóxido Dismutase/antagonistas & inibidores , Superóxido Dismutase/biossíntese , Vibrio cholerae/enzimologia
9.
Melanoma Res ; 8(2): 131-7, 1998 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-9610865

RESUMO

Theophylline- and caffeine-treated B16-F10 cells exhibited low adhesion to laminin/collagen type IV and reduced invasion through Matrigel in an in vitro assay. In contrast, theobromine appeared ineffective. When young adult C57BL/6 mice were injected intravenously with theophylline-treated B16-F10 cells, the number of surface lung tumours was markedly reduced. Densitometric analyses performed on digitalized microscopic images of histological sections of lung were used to estimate the frequency (number of lung foci; NLF) and the size (average area of metastatic foci; AMF) of the resulting tumour foci. These parameters were correlated to the proliferation (AMF) and invasion (NLF) of melanoma cells in vivo. The data showed a similar theophylline-induced decrease in the AMF and NLF values (71%, P < 0.01). Caffeine treatment produced a more pronounced decrease in the AMF (61%, P < 0.01) than in the NLF (25%, P < 0.01). To our knowledge, this is the first demonstration that theophylline and caffeine possess the capacity to inhibit not only cell proliferation, but also the metastatic behaviour of melanoma cancer cells.


Assuntos
Cafeína/farmacologia , Neoplasias Pulmonares/secundário , Melanoma Experimental/patologia , Melanoma Experimental/secundário , Teobromina/farmacologia , Teofilina/farmacologia , Animais , Adesão Celular/efeitos dos fármacos , Divisão Celular , Colágeno , Laminina , Neoplasias Pulmonares/metabolismo , Neoplasias Pulmonares/patologia , Neoplasias Pulmonares/prevenção & controle , Masculino , Melaninas/metabolismo , Melanoma Experimental/metabolismo , Melanoma Experimental/prevenção & controle , Camundongos , Camundongos Endogâmicos C57BL , Monofenol Mono-Oxigenase/metabolismo , Invasividade Neoplásica , Transglutaminases/metabolismo , Células Tumorais Cultivadas
10.
Minerva Med ; 73(28-29): 1963-9, 1982 Jul 14.
Artigo em Italiano | MEDLINE | ID: mdl-6212775

RESUMO

It has been found that the public's knowledge of genetic diseases and their prevention was extremely limited in the Commune of Castel San Pietro Terme (Bologna). This lack of information was common to all categories covered by the poll. In spite of this, the public was generally in favour of a genetic consultancy service. Overall figures reveal that 84.06% of men and 79.58% of women interviewed would use the information provided by genetic consultancy for preventive purposes.


Assuntos
Aconselhamento Genético , Aceitação pelo Paciente de Cuidados de Saúde , Síndrome de Down/prevenção & controle , Serviços de Planejamento Familiar , Feminino , Doenças Genéticas Inatas/prevenção & controle , Humanos , Itália , Masculino , Meios de Comunicação de Massa , Educação de Pacientes como Assunto , Gravidez , Diagnóstico Pré-Natal , Talassemia/prevenção & controle
11.
Minerva Med ; 73(28-29): 1971-8, 1982 Jul 14.
Artigo em Italiano | MEDLINE | ID: mdl-6212776

RESUMO

At Cabras (Oristano), a town characterized by a high incidence of thalassaemia and G6PD deficiency less than half the people between 18 and 35 have a fair knowledge of genetic diseases and of their prevention. The lack of information is higher among people working in the primary sector, housewives and generally, among those who are uneducated. The majority of the people we have interviewed are favourable to undergo analysis to single out carriers. Of these many have said to be unwilling to give birth to children if they belong to a couple at risk. Other have said they do not exclude of having children all the same but to be willing to amniocentesys, and to miscarriage if necessary. From a total calculation results that 88,03% of the men and 82,18% of the women we have interviewed would use, as a prevention, the information obtained from a genetic centre.


Assuntos
Aconselhamento Genético , Doenças Genéticas Inatas/prevenção & controle , Aceitação pelo Paciente de Cuidados de Saúde , Adulto , Síndrome de Down/prevenção & controle , Serviços de Planejamento Familiar , Humanos , Itália , Meios de Comunicação de Massa , Educação de Pacientes como Assunto , Talassemia/prevenção & controle
12.
Minerva Med ; 74(8): 395-400, 1983 Feb 28.
Artigo em Italiano | MEDLINE | ID: mdl-6220233

RESUMO

At Cento (Ferrara), a town characterized by a moderate incidence of thalassemia, only 8.62% of men and 16.53% of women have a fair knowledge of genetic diseases and of their prevention. This lack of information was common to all categories covered by the poll. In spite of this, public was generally in favour of a genetic consultancy service. Table 1 reveals that 74.14% of men and 83.47% of women would use the informations provided by genetic consultancy for preventive purposes.


Assuntos
Comportamento do Consumidor , Aconselhamento Genético , Atitude , Síndrome de Down/epidemiologia , Síndrome de Down/genética , Feminino , Humanos , Masculino , Estudos de Amostragem , Fatores Sexuais , Inquéritos e Questionários , Talassemia/epidemiologia , Talassemia/genética
13.
Clin Microbiol Infect ; 20(10): O694-701, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-24575948

RESUMO

HBsAg-negative/HBcAb-positive haematopoietic stem cell transplant (HSCT) recipients are at high risk of hepatitis B virus (HBV) reactivation. Allogeneic HSCT recipients from years 2000 to 2010 were evaluated in order to study the impact of being HBsAg-negative/HBcAb-positive in this population. Overall, 137 of 764 patients (18%) were HBsAg-negative/HBcAb-positive before HSCT. Overall survival, non-relapse mortality (NRM), acute and chronic graft-vs.-host disease were similar in HBcAb-positive and HBcAb-negative patients. Reactivation occurred in 14 patients (10%) within a median of 19 months after HSCT (range 9-77). Cause-specific hazard for reactivation was decreased in the case of an HBV-immune/exposed donor (HRadjusted = 0.12; 95% CI, 0.02-0.96; p 0.045) and increased in patients who received rituximab treatment (HRadjusted = 2.91; 95%CI, 0.77-10.97; p 0.11). Competing risk analyses documented a protective role of an HBV-immune/exposed donor (p 0.041) and an increased probability associated with the length of treatment with cyclosporine (p <0.001) and treatment with rituximab (but not with low-dose rituximab prophylaxis, p <0.001 at each landmark point). No differences in overall survival and NRM were found between patients with and without HBV reactivation. The donor's immunity was independently and consistently associated with a decreased risk of HBV reactivation, while rituximab and cyclosporine treatments increased the probability.


Assuntos
Transplante de Células-Tronco Hematopoéticas/efeitos adversos , Antígenos de Superfície da Hepatite B/análise , Vírus da Hepatite B/fisiologia , Ativação Viral , Adolescente , Adulto , Idoso , Anticorpos Monoclonais Murinos/efeitos adversos , Criança , Ciclosporina/efeitos adversos , Feminino , Doença Enxerto-Hospedeiro/imunologia , Humanos , Imunossupressores/efeitos adversos , Masculino , Pessoa de Meia-Idade , Fatores de Risco , Rituximab , Análise de Sobrevida , Transplantados , Transplante Homólogo , Resultado do Tratamento , Adulto Jovem
14.
Biochem J ; 305 ( Pt 3): 725-8, 1995 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-7848270

RESUMO

Protein synthesis initiation factor 5A (eIF-5A) from human erythrocytes was found to be a substrate for both plasma transglutaminase (Factor XIIIa) and guinea pig liver transglutaminase (GPLTG). When purified eIF-5A was incubated with GPLTG or Factor XIIIa in the presence of succinylated beta-casein, a covalent complex was identified. By isolating and analysing the product of the transglutaminases (TGases) reaction, the site of modification on eIF-5A has been identified as the unique amino acid hypusine. The complex beta-casein.eIF-5A was enzymatically digested with proteinases and the predicted covalent cross-link of gamma-glutamyl-omega-hypusine was isolated from the digests by ion-exchange chromatography and purified by reversed-phase h.p.l.c. Acid hydrolysis of the purified dipeptide yielded equimolar amounts of hypusine and glutamic acid. Furthermore, fast atom bombardment m.s. analysis confirmed the isomer assignment to be gamma-glutamyl-omega-hypusine. These data indicate that hypusine-50 of the eIF-5A chain functions as acyl acceptor substrate for TGases, and reveal that eIF-5A may be cross-linked to intracellular proteins by TGases. Because the precise function of eIF-5A is still unknown, our results appear particularly stimulating in the light of the recent finding of a new biological role for this protein as a cellular factor binding specifically to the human immunodeficiency virus-1 Rev activation domain [Ruhl, Himmelspach, Bahr, Hammerschmid, Jaksche, Wolff, Auschauer, Farrington, Probst, Bevec and Hauber (1993) J. Cell Biol. 123, 1309-1320].


Assuntos
Fatores de Iniciação de Peptídeos/metabolismo , Proteínas de Ligação a RNA , Transglutaminases/metabolismo , Animais , Sítios de Ligação , Caseínas/metabolismo , Cromatografia Líquida de Alta Pressão , Cromatografia por Troca Iônica , Eletroforese em Gel de Poliacrilamida , Eritrócitos/química , Ácido Glutâmico/metabolismo , Cobaias , Humanos , Cinética , Fígado/enzimologia , Lisina/análogos & derivados , Lisina/metabolismo , Fatores de Iniciação de Peptídeos/química , Fator de Iniciação de Tradução Eucariótico 5A
15.
Protein Eng ; 9(4): 323-5, 1996 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-8738207

RESUMO

The thermal stability of two single (K3R, K67R) and one double (K3R-K67R) mutants of Xenopus laevis B Cu, Zn superoxide dismutase has been studied to test Lys --> Arg substitution as an 'electrostatically conservative' strategy to increase protein stability. The K3R mutant displays an increased thermostability with respect to the wild-type enzyme, whilst a decreased stability was observed in the case of the K67R and K3R-K67R mutants. Concentration dependence of the apparent inactivation constant (kapp) of the latter mutants, as compared to that of the wild type enzyme and K3R mutant, indicates that their higher sensitivity to heat inactivation is due to a perturbation of the dimer association. These results are confirmed also by fluorescence anisotropy measurements of the internal probe Tyr149. The possible role of Arg67 in perturbing the dimer dissociation equilibrium toward the monomeric form is discussed.


Assuntos
Arginina/genética , Estabilidade Enzimática/genética , Lisina/genética , Mutação , Superóxido Dismutase/química , Animais , Simulação por Computador , Modelos Moleculares , Mutagênese Sítio-Dirigida , Superóxido Dismutase/genética , Xenopus laevis
16.
Biochem J ; 324 ( Pt 3): 737-41, 1997 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-9210396

RESUMO

We previously found that interferon alpha2 recombinant (IFNalpha) increases the expression of epidermal growth factor receptor (EGF-R) in the human epidermoid cancer KB cell line. Here we report the effects of IFNalpha and epidermal growth factor (EGF) on KB cell cycle kinetics. IFNalpha (1000 i.u./ml) for 48 h decreased the S-phase fraction and diminished the expression of Ki67 and proliferating cell nuclear antigen on KB cells. Incubation of IFNalpha-treated KB cells with 10 nM EGF for 12 h reversed these effects. We then studied several biochemical markers of cell proliferation. Ornithine decarboxylase activity was decreased to about one-tenth by IFNalpha and partly restored by EGF. Hypusine is contained only in eukaryotic initiation factor 5A and its levels are correlated with cell proliferation. IFNalpha decreased hypusine synthesis by 75%; exposure of cells to EGF for 12 h restored hypusine synthesis almost completely. We also studied the effects of IFNalpha on the cytotoxicity of the recombinant toxin TP40, which inhibits elongation factor 2 through EGF-R binding and internalization. IFNalpha greatly enhanced the TP40-induced inhibition of protein synthesis in KB cells. In conclusion, IFNalpha, which affects protein synthesis machinery and increases EGF-R expression, enhances the tumoricidal activity of TP40 and hence could be useful in the setting of anti-cancer therapy.


Assuntos
Carcinoma de Células Escamosas/patologia , Divisão Celular/efeitos dos fármacos , Fator de Crescimento Epidérmico/farmacologia , Interferon-alfa/farmacologia , Lisina/análogos & derivados , Neoplasias Orofaríngeas/patologia , Antineoplásicos/farmacologia , Carcinoma de Células Escamosas/enzimologia , Carcinoma de Células Escamosas/metabolismo , Ciclo Celular/efeitos dos fármacos , Exotoxinas/farmacologia , Humanos , Interferon alfa-2 , Lisina/biossíntese , Ornitina Descarboxilase/metabolismo , Neoplasias Orofaríngeas/enzimologia , Neoplasias Orofaríngeas/metabolismo , Proteínas Recombinantes , Fator de Crescimento Transformador alfa/farmacologia , Células Tumorais Cultivadas
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