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1.
J Craniomaxillofac Surg ; 42(8): 2045-8, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25458343

RESUMO

For the definitive treatment of lagophthalmos and satisfactory rehabilitation of the affected eye, different surgical strategies have been proposed, including static or dynamic procedures. Although some of these can have good results, lid loading is now the most common technique for treating paralytic long-term lagophthalmos. Among the different types of loading, the use of a platinum chain is preferred to the use of a standard gold weight because platinum has a higher density than gold and is also more biocompatible. In this paper authors retrospectively analyzed 43 patients with regards to functional and cosmetic results. Questionnaires were also employed to assess changes and improvements in the patients' quality of life. Analysis of the excellent results achieved confirmed that platinum chain lid loading should be considered as a first-line treatment for paralytic lagophthalmos rehabilitation. It is a simple, reliable, and effective technique that significantly improves the health-related quality of life of patients.


Assuntos
Materiais Biocompatíveis/química , Doenças Palpebrais/cirurgia , Pálpebras/cirurgia , Platina/química , Próteses e Implantes , Implantação de Prótese , Adulto , Idoso , Piscadela/fisiologia , Cicatriz/patologia , Dissecação/métodos , Estética , Paralisia Facial/cirurgia , Feminino , Seguimentos , Humanos , Ceratite/cirurgia , Masculino , Pessoa de Meia-Idade , Satisfação do Paciente , Qualidade de Vida , Estudos Retrospectivos , Técnicas de Sutura , Lágrimas/metabolismo , Visão Ocular/fisiologia , Adulto Jovem
2.
J Craniomaxillofac Surg ; 42(6): 1005-9, 2014 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-24642090

RESUMO

BACKGROUND: The submental island flap is an axial pattern skin flap first described by Martin et al. in 1993. When used to reconstruct skin defects it matches the recipient site in terms of colour, texture and thickness. One of the main limitations to its application is the arc of the pedicle allowing coverage of only the lower two thirds of the face. METHODS: A retrospective review was performed of all patients who had had a submental island flap reconstruction at the Operative Unit of Maxillo-Facial Surgery of the University Hospital of Parma, Italy, between 2001 and 2011. The Authors focused on the surgical technique adopted, the clinical indications and the results obtained. They analysed the different ways to elongate the pedicle and discuss their thoughts on the choice of reconstruction. A flowchart was created to help in the decisional process. RESULTS: Between 2001 and 2011 the submental island flap was used to reconstruct head and neck defects in 22 patients. Thirteen patients had defects of the oral cavity; the remaining 9 patients had skin defects involving the pre-auricular region, the temporal area and the peri-nasal cheek skin. No major complications occurred and in one case a partial necrosis of the distal portion of the flap was observed. Five patients underwent surgical revision involving intraoral flap debulking 6-10 months after the primary procedure. DISCUSSION AND CONCLUSIONS: The techniques to elongate the pedicle used and described were: additional dissection of the pedicle, Y-V procedure, reverse flow flap, section of facial vein and microvascular anastomosis. Their choice is mainly conditioned by the site of the defect.


Assuntos
Cabeça/cirurgia , Pescoço/cirurgia , Procedimentos de Cirurgia Plástica/métodos , Transplante de Pele/métodos , Retalhos Cirúrgicos/transplante , Idoso , Idoso de 80 Anos ou mais , Anastomose Cirúrgica/métodos , Carcinoma de Células Escamosas/cirurgia , Bochecha/cirurgia , Árvores de Decisões , Otopatias/cirurgia , Orelha Externa/cirurgia , Neoplasias Faciais/cirurgia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Neoplasias Bucais/cirurgia , Estudos Retrospectivos , Couro Cabeludo/cirurgia , Neoplasias Cutâneas/cirurgia , Retalhos Cirúrgicos/irrigação sanguínea
3.
Int J Oral Maxillofac Surg ; 42(9): 1129-33, 2013 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-23702372

RESUMO

The authors' experience of the selective deep lobe parotidectomy for the treatment of pleomorphic adenomas of the deep parotid lobe is presented. A retrospective analysis of 11 patients treated between 1997 and 2010 was performed; seven were males and four were females, ranging in age from 35 to 51 years. Parameters evaluated included facial nerve weakness, the occurrence of Frey's syndrome, cosmetic outcome, and recurrence. Follow-up ranged from 18 months to 11 years. No major complications, permanent facial nerve weakness, or Frey's syndrome occurred. Four patients developed temporary facial nerve impairments that lasted between 2 and 6 weeks, and two developed a sialocele that healed in 9 days in one case and 12 days in the other. The overall cosmetic assessment was excellent in eight patients, good in two, and satisfactory in the remaining one. No recurrences occurred. The selective deep lobe parotidectomy can be considered an effective technique for the management of deep parotid lobe pleomorphic adenomas. The major advantages of this procedure include a reduction in complications such as facial nerve impairments and Frey's syndrome, and an improved cosmetic outcome.


Assuntos
Adenoma Pleomorfo/cirurgia , Glândula Parótida/cirurgia , Neoplasias Parotídeas/cirurgia , Adulto , Cistos/etiologia , Dissecação/métodos , Orelha Externa/inervação , Estética , Nervo Facial/anatomia & histologia , Doenças do Nervo Facial/etiologia , Paralisia Facial/etiologia , Fasciotomia , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Músculos do Pescoço/cirurgia , Doenças Parotídeas/etiologia , Complicações Pós-Operatórias , Estudos Retrospectivos , Sudorese Gustativa/etiologia
4.
J Craniomaxillofac Surg ; 41(2): 172-8, 2013 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-22910278

RESUMO

PURPOSE: To evaluate the clinical outcome and the aesthetic and functional results of implant rehabilitation of fibula free-flap reconstructed mandibles. MATERIALS AND METHODS: The charts of patients who underwent mandibular reconstruction with fibula free flap and implant prosthodontic rehabilitation between 1998 and 2008 at the Operative Unit of Maxillofacial Surgery of Parma, Italy, were reviewed. In the study the estimated survival rates of implants placed in reconstructed mandibles we identified the prognostic factors and evaluated the functional outcomes. RESULTS: Fourteen patients with a mean age of 50 years (range 15-63 years), were included in the study. A total of 62 implants were positioned. Complications occurred in 7 cases, an improvement in function and aesthetics was reported by the majority of patients. CONCLUSIONS: A high survival rate for implants placed in fibula free-flap reconstructed mandibles was observed. Although different factors were believed to be associated with a poorer prognosis (radiotherapy, composite defects, etc.) no statistically significance was found, showing no absolute contraindications to implant placement.


Assuntos
Transplante Ósseo/métodos , Implantes Dentários , Retalhos de Tecido Biológico/transplante , Mandíbula/cirurgia , Procedimentos de Cirurgia Plástica/métodos , Adolescente , Adulto , Deglutição/fisiologia , Prótese Dentária Fixada por Implante , Falha de Restauração Dentária , Ingestão de Alimentos/fisiologia , Estética Dentária , Feminino , Seguimentos , Humanos , Masculino , Neoplasias Mandibulares/cirurgia , Pessoa de Meia-Idade , Complicações Pós-Operatórias , Prognóstico , Estudos Retrospectivos , Transplante de Pele/métodos , Inteligibilidade da Fala/fisiologia , Análise de Sobrevida , Resultado do Tratamento , Adulto Jovem
5.
J Craniomaxillofac Surg ; 41(2): 167-71, 2013 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-22883078

RESUMO

INTRODUCTION: Free flaps represent the first reconstructive option for many head and neck defects. The increasing life expectancy of the population results in increasing numbers of ageing patients facing complex reconstructive surgery. In this study we evaluated our experience with free-flap transfers in older patients, analysing the post-operative reconstructive and systemic complications. MATERIALS AND METHODS: Between 2000 and 2009, 360 patients underwent free flap reconstruction of defects resulting from the treatment of head and neck tumours at the Operative Unit of Maxillofacial Surgery, University - Hospital of Parma, Italy. Fifty-five patients (15.3%) were more than 75 years old at the time of treatment. RESULTS: At the end of the follow-up successful free-flap transfer was achieved in 360 of the 373 flaps harvested (96.5%). The overall reconstructive complication rate was 31.4%, (31.8% in the younger group and 29.1% in the remaining patients). Medical complications were observed in 29.2% of cases (less than 75 years: 28.8%; more than 75 years: 30.9%). The ASA status was associated with a statistically significantly higher incidence of complications within patients less than 75 years old (p < 0.0001). DISCUSSION AND CONCLUSIONS: The results of this study, in agreement with previous studies, provide evidence that free-tissue transfer may be performed in ageing patients with a high degree of technical success. The chronologic age cannot be considered an appropriate criterion in the reconstructive decision. On the contrary, a careful selection of the patients based on comorbidities and general conditions (ASA status) is of primary importance in reducing post-operative complications and to improving the results of surgery.


Assuntos
Retalhos de Tecido Biológico/transplante , Neoplasias de Cabeça e Pescoço/cirurgia , Procedimentos de Cirurgia Plástica/métodos , Complicações Pós-Operatórias , Adulto , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Consumo de Bebidas Alcoólicas , Alcoolismo/complicações , Antineoplásicos/uso terapêutico , Doença Crônica , Cuidados Críticos , Complicações do Diabetes , Feminino , Seguimentos , Sobrevivência de Enxerto , Nível de Saúde , Hospitalização , Humanos , Tempo de Internação , Masculino , Pessoa de Meia-Idade , Duração da Cirurgia , Radioterapia Adjuvante , Fumar , Taxa de Sobrevida , Resultado do Tratamento
6.
J Craniomaxillofac Surg ; 41(1): e1-4, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-22878220

RESUMO

Moebius syndrome is a rare disorder found in approximately 1/100,000 neonates and the treatment of facial palsy is now well established worldwide and consists of free-muscle transplants reinnervated with motor nerves. Dentofacial deformities are often detected in Moebius patients, and different degrees of micrognathia are often present, particularly in patients with complete expressions of Moebius syndrome. However only two published reports have described the surgical treatment of such anomalies in these patients; in both cases, the suggested approach consisted of orthognathic surgery followed by soft-tissue management. In this paper we discuss the indications and correct timing of orthognathic surgery and suggest to perform facial animation at an early age and then to wait for the completion of maxillofacial skeletal growth before performing orthognathic surgery. Finally, facial animation should precede orthognathic surgery in adult patients to prevent lower lip deformities and to ensure more predictable and satisfactory results.


Assuntos
Síndrome de Möbius/cirurgia , Procedimentos Cirúrgicos Ortognáticos/métodos , Queixo/cirurgia , Expressão Facial , Paralisia Facial/cirurgia , Seguimentos , Retalhos de Tecido Biológico/inervação , Retalhos de Tecido Biológico/transplante , Humanos , Lábio/cirurgia , Masculino , Má Oclusão Classe II de Angle/terapia , Avanço Mandibular/métodos , Músculo Masseter/inervação , Neurônios Motores/transplante , Músculo Esquelético/inervação , Músculo Esquelético/transplante , Técnica de Expansão Palatina , Fatores de Tempo , Técnicas de Movimentação Dentária/métodos , Resultado do Tratamento , Adulto Jovem
7.
Clin Otolaryngol ; 35(2): 118-24, 2010 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-20500581

RESUMO

OBJECTIVE: To discuss the prognostic factors and outcomes of treatment in patients diagnosed with papillary thyroid microcarcinoma. DESIGN: Retrospective observational case review. SETTING: Department of Otorhinolaryngology of the tertiary referral teaching hospital of Parma. PARTICIPANTS: Ninety-seven patients diagnosed with PTMC and surgically treated between January 1998 and December 2007. MAIN OUTCOME MEASURES: Clinical and histopathological characteristics of the study group were identified and statistically analysed. RESULTS: No cancer-related deaths were registered. Incidence of recurrent disease was 9% after a 43 month mean follow-up (range 12-120). Univariate analysis detected that metastases in neck lymph nodes at diagnosis (p = 0.025), a tumour >5 mm in size (p = 0.011), the presence of bilateral tumoural foci (p = 0.007), the presence of capsular invasion (p = 0.001), and the presence of vascular invasion (p = 0.004) were related to recurrent disease. On multivariate analysis, the presence of bilateral tumoural foci (p = 0.030), and the presence of capsular invasion (p = 0.005) were significantly related to tumour recurrence. CONCLUSION: The prognosis for patients with papillary thyroid microcarcinoma in this series was excellent, with a 100% survival rate and minimal surgical-related morbidity. Nevertheless, approximately 10% of patients developed recurrent disease; aggressive treatment may be justified depending on the presence or absence of prognostic risk factors.


Assuntos
Carcinoma Papilar/patologia , Carcinoma Papilar/cirurgia , Estadiamento de Neoplasias , Neoplasias da Glândula Tireoide/patologia , Neoplasias da Glândula Tireoide/cirurgia , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Tecnologia de Fibra Óptica , Seguimentos , Humanos , Incidência , Masculino , Pessoa de Meia-Idade , Invasividade Neoplásica , Recidiva Local de Neoplasia/epidemiologia , Prognóstico , Estudos Prospectivos , Estudos Retrospectivos
8.
Surg Oncol ; 19(4): e103-9, 2010 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-20185299

RESUMO

Rhabdomyosarcoma and Ewing's sarcoma are relatively common malignant tumours in paediatric population. In the past, surgery was the mainstay of treatment and survival rates were poor. Afterwards, the development of multi-agent chemotherapy protocols during the past four decades resulted in a dramatic improvement in long-term survival. As a consequence, the significance of surgery has been the subject of critical discussion in the literature. Nowadays the standard treatment of rhabdomyosarcoma and Ewing's sarcoma consists in a multimodal therapy involving chemotherapy, radiotherapy and surgery. Nevertheless, the role of surgery still remains controversial. In particular, the cure of head and neck localizations presents debatable aspects since defined criteria to establish the risks and the benefits of surgical treatment do not exist at this time. This article reviews the role of surgery in children with head and neck rhabdomyosarcoma and Ewing's sarcoma. Indications, feasibility and timing criteria of surgical treatment have been reviewed and extracted from literature. Our case series is also presented.


Assuntos
Neoplasias de Cabeça e Pescoço/cirurgia , Rabdomiossarcoma/cirurgia , Sarcoma de Ewing/cirurgia , Adolescente , Criança , Pré-Escolar , Terapia Combinada/métodos , Estudos de Viabilidade , Feminino , Humanos , Masculino , Medição de Risco , Fatores de Tempo , Resultado do Tratamento
9.
Chemosphere ; 67(2): 322-9, 2007 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-17107704

RESUMO

Several organic compounds of high molecular weight present in soil interact with selenium and may act as active binding agents affecting its availability in soil, and, consequently, selenium uptake by plants. This study is aimed at investigating the effects of polysaccharides on selenium speciation in soil and on selenium absorption by Lactuca sativa L. plants. Three-week-old seedlings were transplanted into pots filled with soil, and sodium selenite at rates of 1.5 and 5mgSekg(-1) of soil, or sodium selenate at a rate of 1.5mgSekg(-1) of soil were applied. Carboxymethylcellulose (CMC) was added to the soil at rates of 0, 3 and 30mgkg(-1) of soil. After 48 and 110d from transplanting plants were harvested, separated into root and shoot, and fresh and dry matter weights were recorded. Total selenium was determined in both soil and plant samples. A sequential extraction was used to investigate the different Se oxidation states and assess the availability of Se in soil after the final harvesting. Both selenite and selenate were absorbed by roots, but plants amended with Se(VI+) showed higher selenium concentration than plants amended with Se(IV+). Selenite appears to be less mobile than selenate both in soil and plants. The addition of carboxymethylcellulose to soil decreased the amount of selenium absorbed by plants. CMC interacted with Se, making it less mobile as evidenced by the increase in the insoluble fractions. The insoluble Se forms in soil may represent environmental Se sinks potentially available for plants if the substrate is re-used for subsequent growth cycles and selenium species are mobilized as a result of biological and chemical processes.


Assuntos
Carboximetilcelulose Sódica/farmacologia , Lactuca/metabolismo , Selênio/metabolismo , Lactuca/efeitos dos fármacos , Raízes de Plantas/metabolismo , Brotos de Planta/metabolismo , Ácido Selênico , Compostos de Selênio/metabolismo , Selenito de Sódio/metabolismo
10.
B-ENT ; 1(3): 107-11, 2005.
Artigo em Inglês | MEDLINE | ID: mdl-16255494

RESUMO

AIM AND BACKGROUND: To investigate patients treated with radiotherapy (RT) for laryngeal squamous cell carcinoma (SCC) in order to estimate the recurrence rate and treatment used as salvage surgery. The survival rate in the group of patients treated with salvage surgery was compared to that of patients who had chemotherapy rather than surgery or who refused any treatment. METHODS: From 1989 to 1999, 185 patients came to our institution for laryngeal SCC. All of them underwent RT as primary treatment. Only patients with a minimum of three years follow-up (n = 143) were included in the study group. RESULTS: The 143 cases included 22 loco-regional recurrences (15.3%) during the minimum three years of follow-up. Recurrence was observed in the larynx in eighteen cases (81.8%), in cervical nodes in one case (4.55%) and in both the larynx and cervical nodes in one case (4.55%). There was peristomal recurrence in two cases (9.1%). Recurrence was observed after an average of 16.3 months. Fourteen patients (63.6%) out of the twenty-two cases of recurrence underwent salvage surgery. Surgery was not performed on the remaining eight patients (36.4%). The global survival rate was 92.3% after three years and 66.6% after five years in the group of patients treated with surgery. The actuarial survival rate was 100% after three years and 83.3% after five years. The global and actuarial survival rate was 20% after three years and 0% after five years in the group of patients who received chemotherapy rather than surgery or who refused any kind of treatment. CONCLUSION: The RT seems to play an important role in the loco-regional control of laryngeal SCC (especially in glottic T1). Salvage surgery for recurrence results in a good survival rate.


Assuntos
Carcinoma de Células Escamosas/radioterapia , Carcinoma de Células Escamosas/cirurgia , Neoplasias Laríngeas/radioterapia , Neoplasias Laríngeas/cirurgia , Recidiva Local de Neoplasia/radioterapia , Recidiva Local de Neoplasia/cirurgia , Terapia de Salvação , Adulto , Idoso , Idoso de 80 Anos ou mais , Carcinoma de Células Escamosas/mortalidade , Feminino , Seguimentos , Humanos , Neoplasias Laríngeas/mortalidade , Masculino , Pessoa de Meia-Idade , Recidiva Local de Neoplasia/mortalidade , Estudos Retrospectivos , Taxa de Sobrevida , Falha de Tratamento
11.
Clin Otolaryngol Allied Sci ; 29(5): 545-8, 2004 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-15373871

RESUMO

Gastroesophageal reflux disease is associated with various otolaryngological disorders. The aim of this retrospective study was to determine the role of gastroesophageal reflux disease in the development of laryngeal squamous cell carcinoma (SCC) in non-smoking and non-drinking patients. The study population consisted of 36 consecutive non-smoking and non-drinking patients with histologically confirmed SCC of the larynx. As a control, a group of 125 lifetime non-smoking and non-drinking cancer-free subjects were selected. Patients with laryngeal cancer had a higher prevalence of gastroesophageal reflux disease than the control subjects (P < 0.0001). Our results confirm the fact that gastroesophageal reflux disease in itself is associated with an increased risk of laryngeal cancer.


Assuntos
Carcinoma de Células Escamosas/etiologia , Refluxo Gastroesofágico/complicações , Neoplasias Laríngeas/etiologia , Idoso , Carcinoma de Células Escamosas/diagnóstico , Carcinoma de Células Escamosas/epidemiologia , Esofagoscopia/métodos , Feminino , Refluxo Gastroesofágico/diagnóstico , Refluxo Gastroesofágico/epidemiologia , Gastroscopia/métodos , Humanos , Neoplasias Laríngeas/diagnóstico , Neoplasias Laríngeas/epidemiologia , Masculino , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Prevalência , Estudos Retrospectivos , Índice de Gravidade de Doença
12.
Acta Otorhinolaryngol Belg ; 57(2): 113-7, 2003.
Artigo em Inglês | MEDLINE | ID: mdl-12836467

RESUMO

According to recent advances it is assumed that the gastroesophageal reflux (GER) is a possible co-promoting factor of the squamous-cell carcinoma development in the upper parts of the gastro-intestinal and respiratory systems, considering the higher frequency of lesions due to acid in the studied population interested by GER. The aim of this study is to investigate 274 patients with malignant neoplasm of the oral cavity, of the pharynx and of the larynx, by esophago-gastro-duodenoscopy (EGD) and to compare the incidence of GER in this group with a control group of healthy patients from their hospital. Acid exposure in the upper level of the esophagus often remains unknown using traditional pH-monitoring, especially if no pharyngeal probe is used. When necessary a good diagnostic test is EGD with mucosa biopsy; it allows to directly examine the lesion. We retrospectively studied the data of 274 patients suffering from a cancer of the upper aero-digestive tracts by EGD in order to diagnose lesions caused by GER. We compared non-smoking patients affected by GER and tumours a control group of healthy patients. Statistical analysis revealed a significant difference between the two groups using the z-Test (p = 0.0001). In our study, based on endoscopic data, we observed a high percentage of non-smoking patients affected by GER and squamous-cell carcinoma of the upper parts of the airways and the gastrointestinal system. For this reason we consider GER as a possible co-promoting factor of cancer in some patients.


Assuntos
Carcinoma de Células Escamosas/etiologia , Refluxo Gastroesofágico/complicações , Neoplasias Laríngeas/etiologia , Neoplasias Bucais/etiologia , Neoplasias Faríngeas/etiologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Carcinoma de Células Escamosas/diagnóstico , Carcinoma de Células Escamosas/epidemiologia , Endoscopia do Sistema Digestório , Feminino , Refluxo Gastroesofágico/fisiopatologia , Humanos , Neoplasias Laríngeas/diagnóstico , Neoplasias Laríngeas/epidemiologia , Masculino , Pessoa de Meia-Idade , Neoplasias Bucais/diagnóstico , Neoplasias Bucais/epidemiologia , Estadiamento de Neoplasias , Neoplasias Faríngeas/diagnóstico , Neoplasias Faríngeas/epidemiologia , Estudos Retrospectivos , Fatores de Risco , Sensibilidade e Especificidade
13.
Ann Chim ; 91(5-6): 229-38, 2001.
Artigo em Inglês | MEDLINE | ID: mdl-11507826

RESUMO

The paper deals with the study of selenium speciation in a water system where antropic contribution could be relevant (Tiber river). The speciation at natural levels was determined before, inside, after the city of Rome by a previously defined method: the tetravalent state is prevalent in the anthropized zone while the highest oxidation state is predominant outside. The study of the storage effects (on a whole sample) and the distribution (fate) of the selenium contribution were also carried out. The study showed how in polluted waters the fraction of dissolved organic matter able to bind Se(IV) highly affects the mobility of selenium in the matrix. Polysaccharide species show this property, so they are be very probably responsible for the adsorption of selenium on particulate and stabilize this form against oxidation.


Assuntos
Polissacarídeos/química , Selênio/química , Poluentes da Água/análise , Adsorção , Disponibilidade Biológica , Oxirredução , Tamanho da Partícula
14.
Eur J Biochem ; 268(16): 4537-43, 2001 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-11502215

RESUMO

Recombination of two fragments of horse cytochrome c (the heme-containing N-fragment, residues 1-56, and the C-fragment, residues 57-104), which are substantially unstructured at neutral pH, gives rise to a 1:1 fragment complex with a compact conformation, in which the alpha helical structure and the native Met80-Fe(III) axial bond are recovered. With respect to the native protein, the ferric complex shows a less rigid atomic packing and a decreased stability [Delta(DeltaG(o))D = 14.7 kJ.mol(-1)], ascribed to perturbations involving the Trp59 microenvironment and, to a lower extent, the heme pocket region. The redox potential, E1/2 = 234 +/- 5 mV vs. normal hydrogen electrode at 25 degrees C, is close to that of the intact protein, consistent with recovery of the native Met80-heme Fe(III) axial bond. Furthermore, the fragment complex shows reactivity similar to intact cytochrome c, in the reaction with cytochrome c oxidase. We conclude that the absence in the complex of some native cross-links and interlocked packing important for protein rigidity and stability is not as relevant for maintaining the native redox properties of the protein, provided that some structural requirements (i.e. recovering of the native-like alpha helical structure) are fulfilled and coordination of Met80 to the heme-iron is restored.


Assuntos
Grupo dos Citocromos c/química , Animais , Dicroísmo Circular , Grupo dos Citocromos c/metabolismo , Estabilidade Enzimática , Cavalos , Oxirredução
15.
Bioelectrochemistry ; 54(1): 17-22, 2001 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-11506970

RESUMO

This paper describes an electrochemical biosensor for free cholesterol monitoring. The sensor is a multienzymatic electrodic system in which horseradish peroxidase and cholesterol oxidase are simultaneously immobilized within a polymeric film, on the surface of a pyrolitic graphite electrode. From voltammetric and amperometric (flow-injection) data obtained, the efficiency, reproducibility and stability of the system are discussed. Results obtained, of interest for basic and applied biochemistry, represent a first step for construction of a mediator-free biosensor with potentialities for a successful application in the biosensor area.


Assuntos
Técnicas Biossensoriais , Colesterol Oxidase , Colesterol/análise , Eletroquímica/instrumentação , Enzimas Imobilizadas , Colesterol/metabolismo , Dicroísmo Circular , Análise de Injeção de Fluxo
16.
J Am Chem Soc ; 123(11): 2552-8, 2001 Mar 21.
Artigo em Inglês | MEDLINE | ID: mdl-11456924

RESUMO

Local structure of Fe(III), Cr(III), and Zn(II) cations has been determined on the amorphous sample by means of the difference method used for liquid systems. We recorded energy-dispersive X-ray diffraction spectra of a chelating resin (Chelex 100), containing paired iminodiacetate ions coupled to a styrene-divinylbenzene support, in several ionic forms. Coordination geometry of Fe(III), Cr(III), and Zn(II) metal cations with Chelex 100 resin ligand sites, and conformation of the ligand groups have been determined.

17.
Biochemistry ; 39(41): 12632-8, 2000 Oct 17.
Artigo em Inglês | MEDLINE | ID: mdl-11027143

RESUMO

Several studies have shown that anions induce collapse of acid-denatured cytochrome c into the compact A state having the properties of the molten globule and that the anion charge is the main determinant for the A state stabilization. The results here reported show that the anion size plays a role in determining the overall structure of the A state. In particular, small anions induce formation of an A state in which the native Met80-Fe(III) axial bond is recovered and the nativelike redox properties restored. On the other hand, the A state stabilized by large anions shows a histidine (His26 or His33) as the sixth ligand of the heme-iron, a very weak interaction between Trp59 and the heme propionate, and lacks nativelike redox properties. The two anion-stabilized states show similar stability, indicating that (i) the hydrophobic core (which is equally stabilized by all the anions investigated, independently of their size) is the region that mainly contributes to the macromolecule stabilization, and (ii) the flexible loops are responsible for the spectroscopic (and, thus, structural) and redox differences observed.


Assuntos
Grupo dos Citocromos c/química , Animais , Ânions , Dicroísmo Circular , Eletroquímica , Espectroscopia de Ressonância de Spin Eletrônica , Cavalos , Concentração de Íons de Hidrogênio , Modelos Químicos , Oxirredução , Percloratos/química , Desnaturação Proteica , Dobramento de Proteína , Sais/química , Cloreto de Sódio/química , Compostos de Sódio/química , Espectrometria de Fluorescência , Espectrofotometria Ultravioleta , Relação Estrutura-Atividade , Temperatura , Termodinâmica , Titulometria
18.
Eur Arch Otorhinolaryngol ; 256(8): 395-9, 1999.
Artigo em Inglês | MEDLINE | ID: mdl-10525943

RESUMO

This retrospective study assessed the value of computed tomography (CT) scan with contrast in improving the staging accuracy of indirect and direct laryngoscopy. We compared the preoperative staging obtained by the two latter procedures with postoperative histopathological findings in 187 patients operated on for laryngeal cancer. Of these cancers, 98 were supraglottic, 82 glottic and 7 subglottic in origin. The staging accuracy of laryngoscopy was 51.3% and CT was 70.1%. When the two procedures were combined, the staging accuracy was 80.2%. The accuracy of the CT increased from glottic to supraglottic to subglottic tumors, although the accuracy of laryngoscopy decreased in the same direction. Laryngoscopy alone tended to understage larger tumors (pT3 and pT4), whereas CT underestimated the smaller ones (pT1 and pT2). Our data suggest that in order to plan the best treatment both laryngoscopy and CT should be used in making the diagnosis.


Assuntos
Neoplasias Laríngeas/diagnóstico por imagem , Neoplasias Laríngeas/cirurgia , Laringoscopia/métodos , Tomografia Computadorizada por Raios X , Adulto , Idoso , Idoso de 80 Anos ou mais , Técnicas de Cultura , Feminino , Humanos , Neoplasias Laríngeas/patologia , Laringectomia/métodos , Masculino , Pessoa de Meia-Idade , Invasividade Neoplásica , Estadiamento de Neoplasias , Cuidados Pós-Operatórios , Cuidados Pré-Operatórios , Estudos Retrospectivos
19.
Acta Biomed Ateneo Parmense ; 70(1-2): 13-7, 1999.
Artigo em Inglês | MEDLINE | ID: mdl-11402806

RESUMO

Wide defects resulting after resection of malignant tumors of the head and neck need an adeguate closure. In the last 16 years, 85 pectoralis major myocutaneous island flap procedures were carried out for the immediate reconstruction of surgical defects following extirpation of malignant tumors at various sites of the upper aerodigestive tract. The final functional and cosmetic results were satisfactory. Partial necrosis was observed in four cases. We did not have any cases of total flap necrosis. Post-operative fistulas were encountered in 14 cases (surgical closure was not necessary). The application and complications of the pectoralis major myocutaneous flap placed at cervical level are reviewed. The aspects of postoperative swallowing function of such surgery are discussed. Reconstruction with the pectoralis major myocutaneous flap is a safe and versatile procedure, yielding good clinical and functional results in patients with advanced head and neck tumors.


Assuntos
Neoplasias de Cabeça e Pescoço/cirurgia , Procedimentos de Cirurgia Plástica/métodos , Retalhos Cirúrgicos , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Complicações Pós-Operatórias/epidemiologia , Procedimentos de Cirurgia Plástica/efeitos adversos , Retalhos Cirúrgicos/efeitos adversos
20.
Biochem J ; 332 ( Pt 3): 611-5, 1998 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-9620861

RESUMO

The unmediated electrochemistry of two large Cu-containing proteins, ascorbate oxidase and laccase, was investigated by direct-current cyclic voltammetry. Rapid heterogeneous electron transfer was achieved in the absence of promoters or mediators by trapping a small amount of protein within a solid, electrochemically inert, tributylmethyl phosphonium chloride membrane coating a gold electrode. The problems typical of proteins in solution, such as adsorption on the electrode surface, were avoided by this procedure. In anaerobic conditions, the cyclic voltammograms, run at a scan rate of up to 200 mV/s, showed the electron transfer process to be quasi-reversible and diffusion-controlled. The pH-dependent redox potentials (+360 mV and +400 mV against a normal hydrogen electrode at pH7.0 for ascorbate oxidase and laccase respectively and +390 mV and +410 mV at pH5.5) were similar to those of the free proteins. The same electrochemical behaviour was recorded for the type 2 Cu-depleted derivatives, which contain reduced type 3 Cu, whereas the apoproteins were electrochemically inactive. Under aerobic conditions the catalytic current intensity of holoprotein voltammograms increased up to approx. 2-fold at a low scanning rate, with unchanged redox potentials. The voltammograms of type 2 Cu-depleted proteins and of apoproteins were unaffected by the presence of oxygen. This suggests that electron uptake at the electrode surface involves type 1 Cu and that only in the presence of oxygen is the intramolecular electron transfer to other protein sites rapid enough to be observed. The analogy with available kinetic results is discussed.


Assuntos
Ascorbato Oxidase/química , Oxirredutases/química , Eletroquímica , Eletrodos , Enzimas Imobilizadas , Ouro , Concentração de Íons de Hidrogênio , Cinética , Lacase , Membranas , Compostos Organofosforados , Oxirredução , Termodinâmica
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