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1.
Proc Biol Sci ; 289(1989): 20221649, 2022 12 21.
Artigo em Inglês | MEDLINE | ID: mdl-36515119

RESUMO

Ecosystem structure and function are increasingly threatened by changing climate, with profound effects observed globally in recent decades. Based on standardized visual censuses of reef biodiversity, we describe 27 years of community-level change for fishes, mobile macroinvertebrates and macroalgae in the Tasmanian ocean-warming hotspot. Significant ecological change was observed across 94 reef sites (5-10 m depth range) spanning four coastal regions between three periods (1992-95, 2006-07, 2017-19), which occurred against a background of pronounced sea temperature rise (+0.80°C on average). Overall, fish biomass increased, macroinvertebrate species richness and abundance decreased and macroalgal cover decreased, particularly during the most recent decade. While reef communities were relatively stable and warming was slight between the 1990s and mid-2000s (+0.12°C mean temperature rise), increased abundances of warm affinity fishes and invertebrates accompanied warming during the most recent decade (+0.68°C rise). However, significant rises in the community temperature index (CTI) were only found for fishes, invertebrates and macroalgae in some regions. Coastal warming was associated with increased fish biomass of non-targeted species in fished zones but had little effect on reef communities within marine reserves. Higher abundances of larger fishes and lobsters inside reserves appeared to negate impacts of 'thermophilization'.


Assuntos
Ecossistema , Alga Marinha , Animais , Biodiversidade , Invertebrados , Temperatura , Peixes , Recifes de Corais
2.
Lupus ; 29(1): 27-36, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31801040

RESUMO

BACKGROUND: Systemic lupus erythematosus (SLE) is regarded as a prototype autoimmune disease because it can serve as a means for studying differences between ethnic minorities and sex. Traditionally, all Hispanics have been bracketed within the same ethnic group, but there are differences between Hispanics from Spain and those from Latin America, not to mention other Spanish-speaking populations. OBJECTIVES: This study aimed to determine the demographic and clinical characteristics, severity, activity, damage, mortality and co-morbidity of SLE in Hispanics belonging to the two ethnic groups resident in Spain, and to identify any differences. METHODS: This was an observational, multi-centre, retrospective study. The demographic and clinical variables of patients with SLE from 45 rheumatology units were collected. The study was conducted in accordance with Good Clinical Practice guidelines. Hispanic patients from the registry were divided into two groups: Spaniards or European Caucasians (EC) and Latin American mestizos (LAM). Comparative univariate and multivariate statistical analyses were carried out. RESULTS: A total of 3490 SLE patients were included, 90% of whom were female; 3305 (92%) EC and 185 (5%) LAM. LAM patients experienced their first lupus symptoms four years earlier than EC patients and were diagnosed and included in the registry younger, and their SLE was of a shorter duration. The time in months from the first SLE symptoms to diagnosis was longer in EC patients, as were the follow-up periods. LAM patients exhibited higher prevalence rates of myositis, haemolytic anaemia and nephritis, but there were no differences in histological type or serositis. Anti-Sm, anti-Ro and anti-RNP antibodies were more frequently found in LAM patients. LAM patients also had higher levels of disease activity, severity and hospital admissions. However, there were no differences in damage index, mortality or co-morbidity index. In the multivariate analysis, after adjusting for confounders, in several models the odds ratio (95% confidence interval) for a Katz severity index >3 in LAM patients was 1.45 (1.038-2.026; p = 0.02). This difference did not extend to activity levels (i.e. SLEDAI >3; 0.98 (0.30-1.66)). CONCLUSION: SLE in Hispanic EC patients showed clinical differences compared to Hispanic LAM patients. The latter more frequently suffered nephritis and higher severity indices. This study shows that where lupus is concerned, not all Hispanics are equal.


Assuntos
Progressão da Doença , Lúpus Eritematoso Sistêmico/etnologia , Feminino , Humanos , América Latina/etnologia , Lúpus Eritematoso Sistêmico/fisiopatologia , Masculino , Sistema de Registros , Estudos Retrospectivos , Índice de Gravidade de Doença , Espanha/epidemiologia , População Branca/estatística & dados numéricos
4.
Rhinology ; 56(1): 1-30, 2016 01 31.
Artigo em Inglês | MEDLINE | ID: mdl-28623665

RESUMO

BACKGROUND: Olfactory dysfunction is an increasingly recognised condition, associated with reduced quality of life and major health outcomes such as neurodegeneration and death. However, translational research in this field is limited by heterogeneity in methodological approach, including definitions of impairment, improvement and appropriate assessment techniques. Accordingly, effective treatments for smell loss are limited. In an effort to encourage high quality and comparable work in this field, among others, we propose the following ideas and recommendations. Whilst the full set of recommendations are outlined in the main document, points include the following: - Patients with suspected olfactory loss should undergo a full examination of the head and neck, including rigid nasal endoscopy with small diameter endoscopes. - Subjective olfactory assessment should not be undertaken in isolation, given its poor reliability. - Psychophysical assessment tools used in clinical and research settings should include reliable and validated tests of odour threshold, and/or one of odour identification or discrimination. - Comprehensive chemosensory assessment should include gustatory screening. - Smell training can be helpful in patients with olfactory loss of several aetiologies. CONCLUSIONS: We hope the current manuscript will encourage clinicians and researchers to adopt a common language, and in so doing, increase the methodological quality, consistency and generalisability of work in this field.

5.
Ann Hematol ; 94(5): 789-94, 2015 May.
Artigo em Inglês | MEDLINE | ID: mdl-25482455

RESUMO

Somatic mutations in the CALR gene were recently discovered in a substantial proportion of Philadelphia-negative chronic myeloproliferative neoplasm (cMPN) patients lacking JAK2 and MPL mutations. Somatically acquired defects are not the only pathogenic mechanism involved in these disorders. Since germline JAK2 46/1 haplotype predisposes to cMPN-associated mutations, including JAK2V617F and MPLW515K7L, we evaluated whether the 46/1 haplotype also confers susceptibility to CALR-mutated cMPN, both in sporadic and familial cases. The single-nucleotide polymorphism rs10974944, which tags 46/1, was investigated in 155 sporadic MPN patients and 270 unrelated controls, as well as in 11 familial cMPN cases and 36 unaffected relative controls. As described elsewhere, the 46/1 haplotype was overrepresented, both in sporadic and familial cMPN. In sporadic cMPN, the JAK2 46/1 haplotype was closely associated with JAK2V617F (p = 0.0003) but not with JAK2-nonmutated cases. Analysis of CALR-mutated sporadic cMPN (n = 22) showed no association between CALR mutations and 46/1 haplotype (p = 0.87). Regarding the familial cMPN, the prevalence of carriers of the G allele was higher in familial (81.8%) than in sporadic (62%) cMPN, but it did not differ significantly (p = 0.3). Although we described a family with carriers of both JAK2V617F and CALR mutations, due to the low number of CALR-mutated familial cases, we could not determinate whether the JAK2 46/1 haplotype predisposes or does not to CALR-mutated familial cMPN. We conclude, for the first time, that the 46/1 haplotype, unlike JAK2V617F and MPLW515K7L, is not associated with CALR-mutated cMPN.


Assuntos
Haplótipos/genética , Janus Quinase 2/genética , Transtornos Mieloproliferativos/genética , Polimorfismo de Nucleotídeo Único/genética , Adulto , Idoso , Alelos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Mutação , Cromossomo Filadélfia
6.
Colorectal Dis ; 15(4): 414-22, 2013 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-22974322

RESUMO

AIM: Adjuvant 5-fluorouracil based chemotherapy has demonstrated benefit in Stage III colon cancer but still remains controversial in Stage II. The aim of this study was to analyse the prognostic impact of clinicopathological factors that may help guide treatment decisions in Stage II colon cancer. METHOD: Between 1996 and 2006 data from patients diagnosed with colorectal cancer at Hospital Universitari Bellvitge and its referral comprehensive cancer centre Institut Català d'Oncologia/L'Hospitalet were prospectively included in a database. We identified 432 patients with Stage II colon cancer operated on at Hospital Universitari Bellvitge. The 5-year relapse-free survival (RFS) and colon-cancer-specific survival (CCSS) were determined. RESULTS: The 5-year RFS and CCSS were 83% and 88%, respectively. Lymphovascular or perineural invasion was associated with RFS [hazard ratio (HR) 1.84; 95% CI 1.01-3.35]. Gender (women, HR 0.48; 95% CI 0.23-1) and lymphovascular or perineural invasion (HR 3.51; 95% CI 1.86-6.64) together with pT4 (HR 2.79; 95% CI 1.44-5.41) influenced CCSS. In multivariate analysis pT4 and lymphovascular or perineural invasion remained significantly associated with CCSS. We performed a risk index with these factors with prognostic impact. Patients with pT4 tumours and lymphovascular or perineural invasion had a 5-year CCSS of 61%vs the 93% (HR 5.87; 95 CI 2.46-13.97) of those without any of these factors. CONCLUSION: pT4 and lymphatic, venous or perineural invasion are confirmed as significant prognostic factors in Stage II colon cancer and should be taken into account in the clinical validation process of new molecular prognostic factors.


Assuntos
Neoplasias do Colo/patologia , Recidiva Local de Neoplasia/patologia , Idoso , Vasos Sanguíneos/patologia , Neoplasias do Colo/cirurgia , Intervalo Livre de Doença , Feminino , Humanos , Vasos Linfáticos/patologia , Masculino , Pessoa de Meia-Idade , Invasividade Neoplásica , Estadiamento de Neoplasias , Nervos Periféricos/patologia , Estudos Prospectivos , Medição de Risco , Fatores de Risco , Fatores Sexuais , Taxa de Sobrevida
7.
J Vet Pharmacol Ther ; 36(3): 222-8, 2013 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-22607033

RESUMO

The purpose of this study was to assess the clinical effects of dexmedetomidine, both alone and combined with pethidine or butorphanol, in cats. A prospective randomized blind study was performed. Thirty cats were randomly assigned to three groups of 10 animals: D: dexmedetomidine (20 µg/kg IM); DP: dexmedetomidine (10 µg/kg IM) and pethidine (2.5 mg/kg IM); DB: dexmedetomidine (10 µg/kg IM) and butorphanol (0.4 mg/kg IM). Quality of sedation, analgesia, muscle relaxation and the possibility of performing some clinical procedures were compared using a multifactorial scale. Sedation, analgesia and muscle relaxation increased progressively over time and did not differ in the three protocols. The three protocols facilitated the completion of several clinical procedures. The clinical variables studied showed a similar behaviour in the three protocols and remained close to the baseline, except for a drop in heart rate in protocol D. In conclusion, dexmedetomidine, either alone or combined with pethidine or butorphanol, offers suitable sedation, analgesia and relaxation to perform various clinical procedures in cats.


Assuntos
Butorfanol/farmacologia , Gatos/fisiologia , Dexmedetomidina/farmacologia , Hipnóticos e Sedativos/farmacologia , Meperidina/farmacologia , Animais , Butorfanol/administração & dosagem , Dexmedetomidina/administração & dosagem , Quimioterapia Combinada , Feminino , Hipnóticos e Sedativos/administração & dosagem , Masculino , Meperidina/administração & dosagem
8.
Clin Transl Oncol ; 23(12): 2482-2488, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34081292

RESUMO

INTRODUCTION: Stage IV rectal cancer with resectable disease presents challenging issues, as the radical treatment of the whole disease is difficult. Surgery and chemotherapy (CT) play an unquestionable role, but the contribution of pelvic radiotherapy (RT) is not very clear. METHODS: In 2009, we established a prospective treatment protocol that included CT, short-course preoperative radiotherapy (SCRT) with surgery of the primary tumour and all metastatic locations. RESULTS: Forty patients were included. Eight (20%) patients did not receive CT due to significant comorbidities. Radical surgery treatment was possible in 22 (55%) patients. The mean follow-up was 42.81 months (3.63-105.97). Overall survival at 24 and 36 months was 71.4% and 58.2%, respectively. There was good local control of the disease, as 97.2% of pelvic surgeries were R0 and there were no local recurrences. CONCLUSION: In stage IV with resectable metastatic disease, the proposed therapeutic regimen seems very appropriate in well selected patients able to tolerate the treatment. We bet on the role of pelvic RT, due to the good local control of the disease in our series.


Assuntos
Adenocarcinoma/radioterapia , Neoplasias Pélvicas/radioterapia , Cuidados Pré-Operatórios , Radioterapia/métodos , Neoplasias Retais/radioterapia , Adenocarcinoma/secundário , Adenocarcinoma/cirurgia , Adulto , Idoso , Idoso de 80 Anos ou mais , Terapia Combinada , Feminino , Seguimentos , Humanos , Metástase Linfática , Masculino , Pessoa de Meia-Idade , Neoplasias Pélvicas/secundário , Neoplasias Pélvicas/cirurgia , Prognóstico , Estudos Prospectivos , Neoplasias Retais/patologia , Neoplasias Retais/cirurgia , Taxa de Sobrevida
9.
Farm Hosp ; 33(6): 330-4, 2009.
Artigo em Espanhol | MEDLINE | ID: mdl-20038392

RESUMO

INTRODUCTION: The objective of this study is to analyse the appropriateness and characteristics of drug dose calculation for hospitalised, morbidly obese patients. METHODS: Retrospective, descriptive study of dose calculations for drugs prescribed to hospitalised, morbidly obese patients in a tertiary hospital in 2007. The recommendations prepared by the Pharmacy division are used as a standard. RESULTS: We included 62 patients. The mean number of medications prescribed per patient was 12.1 (4-39), and an average of 2.4 (1-10) are listed in the recommendations. A total of 135 drugs were prescribed. Dose calculations for 81 of the above (60 %) coincided with recommendations and 54 (40 %) did not; there were 51 cases of underdosing and three cases of overdosing. DISCUSSION: Improper dosing was detected for prescriptions in the systemic antibiotic and antithrombin drug groups, with underdosing being more common than overdosing.


Assuntos
Cálculos da Dosagem de Medicamento , Obesidade Mórbida/metabolismo , Adulto , Idoso , Analgésicos/administração & dosagem , Antibacterianos/administração & dosagem , Índice de Massa Corporal , Overdose de Drogas , Feminino , Fibrinolíticos/administração & dosagem , Humanos , Pacientes Internados , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Adulto Jovem
10.
Clin Transl Oncol ; 20(1): 89-96, 2018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-29230692

RESUMO

Cancer of unknown primary site is a histologically confirmed cancer that manifests in advanced stage, with no identifiable primary site following standard diagnostic procedures. Patients are initially categorized based on the findings of the initial biopsy: adenocarcinoma, squamous-cell carcinoma, neuroendocrine carcinoma, and poorly differentiated carcinoma. Appropriate patient management requires understanding several clinical and pathological features that aid in identifying several subsets of patients with more responsive tumors.


Assuntos
Neoplasias Primárias Desconhecidas/diagnóstico , Neoplasias Primárias Desconhecidas/patologia , Neoplasias Primárias Desconhecidas/terapia , Humanos
11.
Clin Transl Oncol ; 20(8): 1087-1092, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-29327240

RESUMO

INTRODUCTION: Geriatric oncology (GO) is a discipline that focuses on the management of elderly patients with cancer. The Spanish Society of Medical Oncology (SEOM) created a Working group dedicated to geriatric oncology in February 2016. OBJECTIVES: The main goal of this study was to describe the current situation in Spain regarding the management of elderly cancer patients through an online survey of medical oncologists. METHODS: A descriptive survey was sent to several hospitals by means of the SEOM website. A personal e-mail was also sent to SEOM members. RESULTS: Between March 2016 and April 2017, 154 answers were collected. Only 74 centers (48%) had a geriatrics department and a mere 21 (14%) medical oncology departments had a person dedicated to GO. The vast majority (n = 135; 88%) had the perception that the number of elderly patients with cancer seen in clinical practice had increased. Eighteen (12%) oncologists had specific protocols and geriatric scales were used at 55 (31%) centers. Almost all (92%) claimed to apply special management practices using specific tools. There was agreement that GO afforded certain potential advantages. Finally, 99% of the oncologists surveyed believed it and that training in GO had to be improved. CONCLUSIONS: From the nationwide survey promoted by the Spanish Geriatric Oncology Working Group on behalf of SEOM, we conclude that there is currently no defined care structure for elderly cancer patients. There is an increasing perception of the need for training in GO. This survey reflects a reality in which specific needs are perceived.


Assuntos
Atenção à Saúde/normas , Avaliação Geriátrica , Geriatria/normas , Oncologia/normas , Neoplasias/terapia , Oncologistas/normas , Equipe de Assistência ao Paciente/normas , Idoso , Atenção à Saúde/organização & administração , Humanos , Espanha , Inquéritos e Questionários
12.
Nat Biotechnol ; 18(8): 857-61, 2000 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-10932155

RESUMO

Medically useful semisynthetic cephalosporins are made from 7-aminodeacetoxycephalosporanic acid (7-ADCA) or 7-aminocephalosporanic acid (7-ACA). Here we describe a new industrially amenable bioprocess for the production of the important intermediate 7-ADCA that can replace the expensive and environmentally unfriendly chemical method classically used. The method is based on the disruption and one-step replacement of the cefEF gene, encoding the bifunctional expandase/hydroxylase activity, of an actual industrial cephalosporin C production strain of Acremonium chrysogenum. Subsequent cloning and expression of the cefE gene from Streptomyces clavuligerus in A. chrysogenum yield recombinant strains producing high titers of deacetoxycephalosporin C (DAOC). Production level of DAOC is nearly equivalent (75-80%) to the total beta-lactams biosynthesized by the parental overproducing strain. DAOC deacylation is carried out by two final enzymatic bioconversions catalyzed by D-amino acid oxidase (DAO) and glutaryl acylase (GLA) yielding 7-ADCA. In contrast to the data reported for recombinant strains of Penicillium chrysogenum expressing ring expansion activity, no detectable contamination with other cephalosporin intermediates occurred.


Assuntos
Acremonium/metabolismo , Cefalosporinas/biossíntese , Acremonium/genética , Cromatografia Líquida de Alta Pressão , Fermentação , Genes Fúngicos , Espectrometria de Massas , Plasmídeos , Recombinação Genética
13.
Clin Transl Oncol ; 9(12): 784-8, 2007 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-18158982

RESUMO

OBJECTIVE: To provide an outpatient facility to improve the management of chemotherapy toxicity in cancer patients. PATIENTS AND METHODS: We set up an oncology acute toxicity unit (OATU) to improve toxicity management. A telephone helpline was the initial contact which filters out inappropriate non-toxicity-related events. Patients were provided an information booklet describing the possible side effects of the chemotherapy and the helpline telephone number. A specialist nurse received the calls and consulted the doctor if necessary. Depending on requirements, the patient's problem was resolved by telephone, or a consultation visit at the OATU was arranged. RESULTS: Between February 1999 and August 2001, 1126 patients made 2007 contacts with the OATU. The most common tumours were breast (26%), colorectal (20%) and lung (20%). The telephone helpline was used in 87% of contacts and 37% were considered inappropriate. Of the 1263 appropriate contacts, the most frequent chemotherapy schedules that had been administered were 5FU-leucovorin (11.2%) and CMF (10.4%). The most frequent side effects were fever (35.5%), diarrhoea (18.5%), mucositis (16.2%) and emesis (13%). The problem was resolved by telephone in 48% of cases and 52% required attendance in the OATU, of which 40% required hospital admission, i.e., 21.1% of the initial appropriate helpline contacts. The most frequent reason was Grade 3-4 neutropenic fever (56.5%). CONCLUSIONS: The OATU enables prompt and efficient access of patients to medical oncology facilities in the event of toxicity due to chemotherapy. Unnecessary emergency room use is avoided while oncology outpatient and hospitalisation facilities are optimised.


Assuntos
Sistemas de Notificação de Reações Adversas a Medicamentos/organização & administração , Antineoplásicos/efeitos adversos , Neoplasias/tratamento farmacológico , Serviço Hospitalar de Oncologia/organização & administração , Ambulatório Hospitalar/organização & administração , Toxicologia/organização & administração , Adolescente , Adulto , Idoso , Antineoplásicos/uso terapêutico , Efeitos Colaterais e Reações Adversas Relacionados a Medicamentos , Feminino , Linhas Diretas/estatística & dados numéricos , Humanos , Masculino , Pessoa de Meia-Idade , Náusea/induzido quimicamente , Telefone , Vômito/induzido quimicamente
14.
Rhinol Suppl ; 54(26): 1-30, 2017 03.
Artigo em Inglês | MEDLINE | ID: mdl-29528615

RESUMO

Background: Olfactory dysfunction is an increasingly recognised condition, associated with reduced quality of life and major health outcomes such as neurodegeneration and death. However, translational research in this field is limited by heterogeneity in methodological approach, including definitions of impairment, improvement and appropriate assessment techniques. Accordingly, effective treatments for smell loss are limited. In an effort to encourage high quality and comparable work in this field, among others, we propose the following ideas and recommendations. Whilst the full set of recommendations are outlined in the main document, points include the following: • Patients with suspected olfactory loss should undergo a full examination of the head and neck, including rigid nasal endoscopy with small diameter endoscopes. • Subjective olfactory assessment should not be undertaken in isolation, given its poor reliability. • Psychophysical assessment tools used in clinical and research settings should include reliable and validated tests of odour threshold, and/or one of odour identification or discrimination. • Comprehensive chemosensory assessment should include gustatory screening. • Smell training can be helpful in patients with olfactory loss of several aetiologies. Conclusions: We hope the current manuscript will encourage clinicians and researchers to adopt a common language, and in so doing, increase the methodological quality, consistency and generalisability of work in this field.


Assuntos
Transtornos do Olfato/diagnóstico , Transtornos do Olfato/terapia , Humanos , Testes Neuropsicológicos , Olfatometria , Percepção Olfatória , Qualidade de Vida
15.
Biochim Biophys Acta ; 967(3): 354-63, 1988 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-3196755

RESUMO

The kinetic mechanism of the reaction catalyzed by glucose-6-phosphate dehydrogenase (EC 1.1.1.49) from Dicentrarchus labrax liver was examined using initial velocity studies, NADPH and glucosamine 6-phosphate inhibition and alternate coenzyme experiments. The results are consistent with a steady-state ordered sequential mechanism in which NADP+ binds first to the enzyme and NADPH is released last. Replots of NADPH inhibition show an uncommon parabolic pattern for this enzyme that has not been previously described. A kinetic model is proposed in agreement with our kinetic results and with previously published structural studies (Bautista et al. (1988) Biochem. Soc. Trans. 16, 903-904). The kinetic mechanism presented provides a possible explanation for the regulation of the enzyme by the [NADPH]/[NADP+] ratio.


Assuntos
Glucosefosfato Desidrogenase/metabolismo , Fígado/enzimologia , NADP/farmacologia , Animais , Bass , Cromatografia em Gel , Cromatografia por Troca Iônica , Glucosefosfato Desidrogenase/antagonistas & inibidores , Glucosefosfato Desidrogenase/isolamento & purificação , Cinética , Matemática , Oxirredução
16.
Biochim Biophys Acta ; 1334(2-3): 123-8, 1997 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-9101705

RESUMO

Arginase is induced in bone marrow-derived macrophages by agents that increase the intracellular concentrations of cAMP (Br-cAMP, prostaglandin E2) and, in their presence, the LPS induced NO synthesis is down regulated. Moreover, interleukin 10 which induces arginase in macrophages is able to increase the cAMP-dependent protein kinase A activity. In contrast, suppressors of NOS synthesis like protein kinase C inhibitors and calmodulin antagonists (W7), or NO activators (A23187) have no effect on the induction of arginase by LPS. These results strongly suggest that PKA is involved in the induction of arginase and supports the hypothesis that there is a reciprocal regulation of these two enzymes that drives the macrophages towards opposite functional states.


Assuntos
Arginase/biossíntese , Proteínas Quinases Dependentes de AMP Cíclico/metabolismo , Macrófagos/enzimologia , Animais , Células da Medula Óssea , Indução Enzimática , Lipopolissacarídeos , Camundongos , Óxido Nítrico Sintase/biossíntese , Proteína Quinase C/antagonistas & inibidores , Transdução de Sinais
17.
Biochim Biophys Acta ; 1339(1): 167-75, 1997 Apr 25.
Artigo em Inglês | MEDLINE | ID: mdl-9165111

RESUMO

Immobilized enzyme derivatives, in organic media at neutral pH and moderate temperatures, should be mainly and perhaps uniquely inactivated by promotion of conformational changes on their 3D structure. Subsequent irreversible inactivation mechanisms (intermolecular aggregations, chemical modifications, thiol-disulfide exchanges) are thus impossible. However, simple reincubation in aqueous medium of enzymes previously inactivated by solvents usually yields significant but slow and incomplete reactivations. Disruption of incorrect protein structures by denaturing agents (urea, guanidine) is proposed as a new strategy to get rapid, complete and technologically feasible reactivations. By using multipoint immobilized chymotrypsin derivatives, we have evaluated the possibility of unfolding and further refolding of native (non-inactivated) derivatives by different denaturing conditions. After unfolding in 8 M guanidine, derivatives were quickly and completely refolded up to 100% of catalytic activity in 10 minutes. Besides, successive cycles of unfolding and refolding could be exactly reproduced. Finally we checked the possibility to reactivate chymotrypsin derivatives inactivated by dioxane. Simple reincubations in aqueous media yielded a poor reactivation even after 24 hours. However, unfolding in 8 M guanidine enabled complete reactivation in less than 2 hours. From this point of view, by working under 'chemically inert conditions' (moderate pH and temperatures), fully dispersed covalently immobilized enzyme derivatives seem to behave as almost everlasting catalysts despite the very deleterious effect of organic media.


Assuntos
Quimotripsina/química , Quimotripsina/metabolismo , Reativadores Enzimáticos/farmacologia , Dobramento de Proteína , Solventes/farmacologia , Animais , Bovinos , Quimotripsina/antagonistas & inibidores , Enzimas Imobilizadas , Conformação Proteica , Desnaturação Proteica , Fatores de Tempo
18.
Biochim Biophys Acta ; 1476(2): 181-90, 2000 Feb 09.
Artigo em Inglês | MEDLINE | ID: mdl-10669784

RESUMO

Arginase I is a homotrimeric protein with a binuclear manganese cluster. At the C-terminus of each monomer, the polypeptide chain forms an unusual S-shaped oligomerization motif where the majority of intermonomer contacts are located [Z.F. Kanyo, L.R. Scolnick, D.E. Ash, D.W. Christianson, Nature 383 (1996) 554-557]. In order to study the implication of this motif in the quaternary structure of human arginase I, we have constructed a truncated arginase lacking the 14 C-terminal amino acids, leaving Arg-308 as the last residue in the sequence. The resulting protein retains its trimeric structure, as determined by gel filtration (molecular mass 94 kDa). The same result was obtained in the presence of high ionic strength (KCl 0.5 M). Both data indicate that neither the S-shaped motif nor Arg-308 are fundamental in keeping the trimeric quaternary structure. Data obtained from intrinsic anisotropy and fluorescence intensity studies allow us to predict that the distance between the two unique tryptophans in the sequence is 2.9 nm in the native arginase and 4.1 nm for the truncated mutant. These distances allow us to assume a different conformational state in the truncated arginase without any change in its quaternary structure, suggesting that the carboxy-terminal motif is not the most prominent domain implicated in the quaternary structure of human arginase. Collisional quenching studies reinforce this possibility, since using I(-) as quenching molecule we were able to distinguish the two tryptophans in the truncated arginase. Moreover, kinetic studies show that the truncated mutant was fully active. In summary, the main conclusion about the structure of the human arginase I, derived from our study, is that the C-terminal S-shaped motif is not basic to the maintenance of the quaternary structure nor to the activity of the protein.


Assuntos
Arginase/química , Conformação Proteica , Sequência de Aminoácidos , Humanos , Dados de Sequência Molecular , Mutação , Relação Estrutura-Atividade
19.
Biochim Biophys Acta ; 1122(1): 99-106, 1992 Jul 13.
Artigo em Inglês | MEDLINE | ID: mdl-1633201

RESUMO

Binding of NADP to glucose-6-phosphate dehydrogenase (G6PD) from Dicentrarchus labrax liver has stabilized its native structure against thermal inactivation, guanidine hydrochloride unfolding and inactivation by tryptic digestion. The time-course of G6PD inactivation by guanidine hydrochloride in the presence of NADP has provided experimental evidence in favor of a conformational drift upon NADP binding to the bass enzyme. Based on the inactivation patterns obtained when the enzyme was treated with guanidine hydrochloride and trypsin, it is proposed that the enzyme conformation induced upon NADP binding is in slow equilibrium with the conformation stabilized in the absence of NADP. FPLC studies have shown that micromolar concentrations of NADP induced oligomerization of G6PD. In addition, the different K0.5 values of NADP binding to the enzyme, ranging from 1-2 microM (from trypsin inactivation) to 90 microM (from titration of the intrinsic fluorescence), suggest a step-wise binding of NADP to the oligomer, with negative cooperativity in the saturation process.


Assuntos
Glucosefosfato Desidrogenase/metabolismo , NADP/metabolismo , Animais , Bass , Ativação Enzimática/efeitos dos fármacos , Glucosefosfato Desidrogenase/química , Guanidina , Guanidinas/farmacologia , Temperatura Alta , Cinética , Fígado/enzimologia , Conformação Proteica , Desnaturação Proteica , Espectrometria de Fluorescência , Tripsina
20.
J Clin Oncol ; 16(3): 1036-9, 1998 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-9508188

RESUMO

PURPOSE: We performed a clinical trial to determine whether postoperative adjuvant chemotherapy with two drugs versus one drug could prolong survival. PATIENTS AND METHODS: From 1985 to 1996, 85 patients with completely resected locally advanced gastric cancer were enrolled. The subjects were randomized into two treatment groups, as follows: mitomycin (MMC) 10 to 20 mg/m2 intravenously (i.v.) on day 1 every 6 weeks plus ftorafur (FT) 500 mg/m2/d for 36 consecutive days; or MMC alone, 10 to 20 mg/m2 i.v. every 6 weeks. All courses were repeated four times. RESULTS: After a median follow-up duration of 62 months, the overall 5-year survival rates were 67% for the MMC-FT group versus 44% for the MMC group (P = .04). Subgroup analysis to compare survival curves using the method of Mantel-Cox showed survival rates significantly in favor of the MMC-FT group in the subsets of patients with node-negative disease (P = .01) and those whose disease was stage IB or II (P = .008). CONCLUSION: Significantly better survival results were observed for MMC-FT versus MMC alone. Subset analysis suggest a strong benefit in patients with node-negative and early-stage resected gastric cancer.


Assuntos
Adenocarcinoma/tratamento farmacológico , Antibióticos Antineoplásicos/uso terapêutico , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Mitomicinas/uso terapêutico , Neoplasias Gástricas/tratamento farmacológico , Adenocarcinoma/cirurgia , Adulto , Idoso , Quimioterapia Adjuvante , Feminino , Gastrectomia , Humanos , Excisão de Linfonodo , Masculino , Pessoa de Meia-Idade , Mitomicinas/administração & dosagem , Esplenectomia , Neoplasias Gástricas/cirurgia , Análise de Sobrevida , Tegafur/administração & dosagem
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