Paulo Bandiera Paiva

Identification of Functionally Conserved Residues With the Use of Entropy-Variability Plots

We introduce sequence entropy–variability plots as a method of analyzing families of protein sequences, and demonstrate this for three well‐known sequence families: globins, ras‐like proteins, and serine‐proteases. The location of an aligned residue position in the entropy–variability plot correlates with structural characteristics, and with known facts about the roles of individual amino acids in the function of these proteins. The large numbers of known sequences in these families allowed us to introduce new filtering methods for variability patterns. The results are discussed in terms of a simple evolutionary model for functional proteins. Proteins 2003;52:544–552.

Sequence analysis reveals how G protein-coupled receptors transduce the signal to the G protein.

Sequence entropy—variability plots based on alignments of very large numbers of sequences—can indicate the location in proteins of the main active site and modulator sites. In the previous article in this issue, we applied this observation to a series of well‐studied proteins and concluded that it was possible to detect most of the residues with a known functional role. Here, we apply the method to rhodopsin‐like G protein–coupled receptors. Our conclusion is that G protein binding is the main evolutionary constraint on these receptors, and that other ligands, such as agonists, act as modulators. The activation of the receptors can be described as a simple, two‐step process, and the residues involved in signal transduction can be identified. Proteins 2003;52:553–560.

Outcomes of laser thermal therapy for recurrent head and neck cancer

Objective: To review the outcomes of a phase II study using laser-induced thermal therapy (LITT) as a palliative treatment for 106 patients with recurrent head and neck tumors. Study Design: Retrospective study. Setting: Tertiary hospital in the United States. Subjects and Methods: The primary endpoints were tumor response and survival. Prognostic values were assessed by the Kaplan-Meier method. Results: The best results were seen in oral cavity tumors, in which mean survival was 29.1 months, as compared to neck tumors (mean 14.4 ± 6.9 months; range 7.5-20.7 months; with a 95% confidence interval). Further analysis showed that clinical factors such as gender, smoking, and alcohol use were not indicators of poor prognosis, whereas neck disease and tumor stage at first treatment were relevant factors. Conclusion: In this study, 40 out of 106 patients treated by LITT remained alive at the end of our follow-up, and a complete response was seen in 24 (22.6%) patients. The highest response rate was seen in oral cavity tumors, which suggests that tumor location at this site may be a predictor of favorable outcome with LITT.

Ultrasound‐Guided Laser‐Induced Thermal Therapy of Malignant Cervical Adenopathy

Objectives: Laser‐induced thermal therapy (LITT) for cancer is a technique whereby a source of energy (laser, radiofrequency, ultrasonic, cryoenergy, and so on) is directly applied into a tumor at various depths. Recent studies have demonstrated the efficiency of ultrasound (UTZ) and magnetic resonance imaging (MRI) for real‐ or “near” real‐time tumor and vessel identification as well as monitoring and quantifying energy‐induced tissue damage. The objective of this study is to report UCLAs experience using UTZ monitoring of Nd:YAG laser thermal ablation of malignant cervical adenopathy in a phase II study.

Characterization of angiotensin I-converting enzyme from anterior gills of the mangrove crab Ucides cordatus

Angiotensin I-converting enzyme (ACE) is a well-known metallopeptidase that is found in vertebrates, invertebrates and bacteria. We isolated from the anterior gill of the crab Ucides cordatus an isoform of ACE, here named crab-ACE, which presented catalytic properties closely resembling to those of mammalian ACE. The enzyme was purified on Sepharose-lisinopril affinity chromatography to apparent homogeneity and a band of about 72 kDa could be visualized after silver staining and Western blotting. Assays performed with fluorescence resonance energy transfer (FRET) selective ACE substrates Abz-FRK(Dnp)P-OH, Abz-SDK(Dnp)P-OH and Abz-LFK(Dnp)-OH, allowed us to verify that crab-ACE has hydrolytic profile very similar to that of the ACE C-domain. In addition, we observed that crab-ACE can hydrolyze the ACE substrates, angiotensin I and bradykinin. The enzyme was strongly inhibited by the specific ACE inhibitor lisinopril (Ki of 1.26 nM). However, in contrast to other ACE isoforms, crab-ACE presented a very particular optimum pH, being the substrate Abz-FRK(Dnp)-P-OH hydrolyzed efficiently at pH 9.5. Other interesting characteristic of crab-ACE was that the maximum hydrolytic activity was reached at around 45°C. The description of an ACE isoform in Ucides cordatus is challenging and may contribute to a better understanding of the biochemical function of this enzyme in invertebrates.

Segurança da Informação em Saúde: Prontuário Eletrônico do Paciente

Cada vez mais, em todas as atividades corporativas e domesticas, transacoes migram para o mundo digital. Em saude, a substituicao dos registros de pacientes, tradicionalmente em papel, para meios eletronicos, apresenta vantagens como custo, disponibilidade e integracao. Porem, para que os beneficios sejam atingidos, o sistema precisa garantir a seguranca das informacoes mantidas e fornecidas por ele. A falta dessa seguranca pode levar a consequencias graves, como processos judiciais e inducao a erros medicos. A gestao da Seguranca da Informacao e complexa, se utiliza de diversas areas de conhecimento e abrange tecnologias, processos e seres humanos. As pesquisas em ciencia da computacao para o desenvolvimento de novas tecnologias de seguranca e para aprimoramento das existentes sao constantes. Em paralelo e de igual importância, sao as pesquisas em ciencia da informacao, direcionando as boas e seguras praticas no controle do ciclo de vida da informacao, pois, a falta de controle adequado no fluxo da informacao, desde o nascimento de um dado ate o seu respectivo descarte, leva a diversas vulnerabilidades. Nesse contexto o PEP (Prontuario Eletronico do Paciente) emergiu como uma evolucao do tradicional prontuario em papel. Este artigo apresenta os requisitos , vantagens e desvantagens dos PEPs, a fim de possibilitar uma melhor seguranca das informacoes do paciente.