In vivo CYP2E1 phenotyping as a new potential biomarker of occupational and experimental exposure to benzene

Assessing CYP2E1 phenotype in vivo may be important to predict individual susceptibility to those chemicals, including benzene, which are metabolically activated by this isoenzyme. Chlorzoxazone (CHZ), a specific CYP2E1 substrate, is readily hydroxylated to 6-OH-chlorzoxazone (6-OH-CHZ) by liver CYP2E1 and the metabolic ratio 6-OH-CHZ/CHZ in serum (MR) is a specific and sensitive biomarker of CYP2E1 activity in vivo in humans. We used this MR as a potential biomarker of effect in benzene-treated rats and, also, in humans occupationally exposed to low levels of benzene. Male Sprague-Dawley rats (375-400 g b.w.) were treated i.p. for 3 days with either a 0.5 ml solution of benzene (5 mmol/kg b.w.) in corn oil, or 0.5 ml corn oil alone. Twenty-four hours after the last injection, a polyethylene glycol (PEG) solution of CHZ (20 mg/kg b.w.) was injected i.p. in both treated and control animals. After 2, 5.10,15, 20,30,45, 60, 90, 120, 180, and 240 min from injection, 0.2 ml blood was taken from the tip tail and stored at -20 degrees C until analysis. A modified reverse phase HPLC method using a 5 mu m Ultrasphere C18 column equipped with a direct-connection ODS guard column, was used to measure CHZ and its metabolite 6-OH-CHZ in serum. No statistically significant difference in the MR was observed, at any sampling time, between benzene-treated and control rats. The concentration-versus-time area under the curve (AUC), however, was lower (p < 0.05, Mann-Whitney test), whereas the systemic clearance was higher (p < 0.05) in treated than in control rats. Eleven petrochemical workers occupationally exposed to low levels of airborne benzene (mean +/- SD, 25.0 +/- 24.4 mu g/m(3)) and 13 non-exposed controls from the same factory (mean +/- SD, 6.7 +/- 4.0 mu g/m(3)) signed an informed consent form and were administered 500 mg CHZ p.o. Two hours later a venous blood sample was taken for CHZ and 6-OH-CHZ measurements. Despite exposed subjects showed significantly higher levels of t,t-MA and S-PMA, two biomarkers of exposure to benzene, than non-exposed workers, no difference in the MR mean values +/- SD was found between exposed (0.59 +/- 0.29) and non-exposed (0.57 +/- 0.23) subjects. So, benzene was found to modify CHZ disposition, but not CYP2E1 phenotype in benzene-treated rats, nor in workers exposed to benzene, probably due to the levels of exposure being too low. (C) 2009 Elsevier B.V. All rights reserved.

O consentimento informado: Qual o seu real valor na prática médica?

Trata-se de um artigo que comenta sobre a real importância do Termo de Consentimento Informado na prática médica. Este documento tem sido cada vez mais usado como uma prática defensiva, a fim de constituir provas para defesa de um eventual processo judicial de responsabilidade médica, desvirtuando assim a idéia original, que seria a de respeitar a autonomia do paciente e delimitar a responsabilidade médica. O documento tem como objetivo mostrar que o médico cumpriu com seu dever de informar. Seu grande valor reside nos casos onde existam riscos de danos irreversíveis ao paciente. Conclui-se, porém, que um prontuário bem elaborado onde se inclui o registro das informações que foram transmitidas, bem como o grau de participação dos pacientes e seus familiares nas decisões terapêuticas, também deve ter valor ético e jurídico semelhante do TCI.

Análise dos aspectos éticos da pesquisa em seres humanos contidos nas Instruções aos Autores de 139 revistas científicas brasileiras

OBJETIVO: Estudar as normas relativas à ética da pesquisa em seres humanos contidas nas Instruções aos Autores de revistas científicas brasileiras. MATERIAL E MÉTODOS: As Instruções aos Autores de 139 revistas científicas brasileiras das áreas de medicina, biomedicina, enfermagem, odontologia e ciências gerais foram analisadas com relação às suas recomendações sobre os aspectos éticos. RESULTADOS: Das 139 revistas estudadas, 110 (79,1%) não fazem referências aos aspectos éticos; 17 (12,2%) exigem aprovação prévia pela Comissão de Ética; três (2,1%) fazem referência à Declaração de Helsinque; uma (0,7%) recomenda adotar o consentimento esclarecido; cinco (3,5%) seguem orientações dos requisitos uniformes para manuscritos submetidos a revistas biomédicas e três (2,1%) seguem princípios, normas e padrões éticos não especificados. Nas 29 revistas que fazem referências à ética, as exigências são solicitadas sob as seguintes formas: 15 (51,7%) exigem a inclusão da informação no texto do artigo; duas (6,8%) pedem carta assinada pelos autores; uma (3,4%) solicita cópia da autorização da Comissão de Ética; uma (3,4%) afirma supor que o autor cumpriu as exigências e dez (34,4%) não fazem qualquer referência específica. CONCLUSÕES: Os resultados do estudo indicam que na maioria das revistas científicas brasileiras há pouca preocupação em relação aos aspectos éticos da pesquisa em seres humanos, contidas nas Instruções aos Autores. Nas revistas que fazem referência aos aspectos éticos, as exigências são muito variáveis.

Checklist de cirurgia segura: análise da segurança e comunicação das equipes de um hospital escola

Este estudo teve como objetivo aplicar o checklist de cirurgia segura, da Organização Mundial de Saúde, nas especialidades cirúrgicas de um hospital escola, e verificar a opinião das equipes sobre a influência da aplicação do checklist na segurança do processo cirúrgico e da comunicação interpessoal da equipe. Trata-se de um estudo de campo, descritivo, analítico, com abordagem qualitativa, realizado no centro cirúrgico de um hospital-escola. Para a coleta de dados, foi aplicado o checklist num total de 30 cirurgias, conduzido pela pesquisadora, em três etapas, e, a seguir, um componente da equipe cirúrgica foi convidado a participar do estudo, assinando o TCLE e respondendo a questões norteadoras. Para organização e análise dos dados, recorremos ao Método de Análise de Conteúdo de Bardin. Os sujeitos não perceberam mudanças na comunicação interpessoal com o uso do checklist, porém, indicaram que o uso proporcionou mais segurança ao procedimento. Adaptações ao checklist foram sugeridas.

Relação entre aleitamento materno e hábitos de sucção não nutritivos

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Alcohol dehydrogenase 3 genotype as a risk factor for upper aerodigestive tract cancers

Objective: To assess alcohol dehydrogenase 3 (ADH3) polymorphism at position Ile349Val as indicator of risk factor for upper aerodigestive tract (UADT) cancer to verify its association with UADT cancer in nonalcoholic or nonsmoking individuals.Design: Cross-sectional study.Setting: Primary care or referral center.Patients: the study group consisted of 141 consecutive patients with newly diagnosed squamous cell carcinoma of the oral cavity, oropharynx, hypopharynx, or larynx admitted for surgical treatment. The comparison group consisted of 94 inpatients without cancer from the A. C. Camargo or other São Paulo (Brazil) hospital and 40 healthy individuals.Intervention: All participants were interviewed and data were collected using a structured questionnaire. After written informed consent was obtained, 20 mL of blood was collected in heparinized tubes.Main Outcome Measures: Odds ratio for ADH3 genotypes using logistic regression models.Results: After adjustment for sex, age, tobacco use, and history of cancer in first-degree family relatives, a significantly higher odds ratio for UADT cancer was observed among individuals with AA genotype and low cumulative alcohol consumption (:5 100 kg of ethanol) (odds ratio=3.8 [95% confidence interval, 1.5-9.7]). A 4-fold increase in odds ratio for UADT cancer among individuals with AA genotype and low tobacco consumption (:525 pack-years) was also found in the adjusted model.Conclusions: These results suggest that genotype AA may be a risk factor for UADT cancer, especially in individuals with low alcohol or tobacco consumption. However, further epidemiological case-control or cohort studies, preferably prospective, are needed to establish the exact role of ADH3 polymorphism and its association with the development of UADT cancers.

Avaliação de Hb A2 e Hb F em doadores de sangue de região malarígena da Amazônia Oriental brasileira por HPLC

In malaria endemic regions of Africa, resistance to infection by Plasmodium has been observed in under 6-month-old children, when there are higher fetal hemoglobin (Hb F) levels. Research performed in the São José do Rio Preto region, central-east Brazil, reported increased levels of Hb F in blood donors. The purpose of this work was to evaluate the A2 hemoglobin (Hb A2) and Hb F concentrations in blood donors deriving from the Brazilian malaria endemic region. Forty-five blood donor samples from Macapá, from patients with varying genders, ages and ethnic origins, were collected by venous puncture after informed consent was obtained. The samples were analyzed by High Performance Liquid Chromatography (HPLC) - System Variant (Bio-Rad). The HPLC demonstrated sensitivity and rapidity in the identification and measurement of the hemoglobins and gave precise results. Moreover, it provided measurement of hemoglobin variants, even when they were present in small amounts, providing a diagnosis of hemoglobinopathies. Hb F levels above the normal were observed in 33.3% of the analyzed samples. The presence of increased Hb F can suggest resistance to infection by Plasmodium falciparum, as there have been reports that infected red blood cells interfere in the development of the parasite.

IN VITRO INCIDENCE of ROOT CANAL BIFURCATION IN MANDIBULAR INCISORS BY RADIOVISIOGRAPHY

Objective: The aim of this study was to verify, in vivo and in vitro, the prevalence of root canal bifurcation in mandibular incisors by digital radiography. Material and Methods: Four hundred teeth were analyzed for the in vivo study. Digital radiographs were taken in an orthoradial direction from the mandibular incisor and canine regions. The digital radiographs of the canine region allowed visualizing the incisors in a distoradial direction using 20 degrees deviation. All individuals agreed to participate by signing an informed consent form. The in vitro study was conducted on 200 mandibular incisors positioned on a model, simulating the mandibular dental arch. Digital radiographs were taken from the mandibular incisors in both buccolingual and mesiodistal directions. Results: The digital radiography showed presence of bifurcation in 20% of teeth evaluated in vitro in the mesiodistal direction. In the buccolingual direction, 17.5% of teeth evaluated in vivo and 15% evaluated in vitro presented bifurcation or characteristics indicating bifurcation. Conclusions: Digital radiography associated with X-ray beam distally allowed detection of a larger number of cases of bifurcated root canals or characteristics of bifurcation.

Cauda equina syndrome after spinal tetracaine: Electromyographic evaluation-20 years follow-up

CAUDA equina syndrome (CES) has long been recognized as a rare complication of spinal anesthesia.(1) CES has been described after administration of spinal anesthetics with lidocaine(2) and bupivacaine.(3) In 1991,(4) CES was reported after continuous spinal anesthesia with 1% tetracaine. In 1980, at our university hospital, six adult female patients underwent perineal gynecologic surgery using a spinal anesthetic of 2 ml tetracaine, 1.2%, in 10% glucose. The concentration of the injected tetracaine was unknown by the anesthetists. In all cases, lumbar puncture was performed at the L3-L4 interspace with a disposable spinal needle while the patients were in the sitting position. CES was first diagnosed 72 h or later postoperatively; previous diagnosis was not possible because patients had an indwelling urethral catheter. The diagnosis of CES was confirmed in all patients. During the past year, after institutional approval and informed consent, clinical, magnetic resonance imaging, electromyographic examinations, and conduction studies were performed in three of the above patients. Examinations were not possible on the other three patients because one had recently died, another could not be located, and the third refused to participate. T1 and T2 magnetic resonance image readings were obtained with Gadolinium contrast from a 0.5 Tesla General Electric apparatus (General Electric, Tokyo, Japan). Bilateral sensory and motor conduction studies of the sciatic nerve branches were obtained using a two-channel Nihon-Kohden Neuropack 2 (Nihom-Kohden Corporation, Tokyo, Japan). Electromyography was performed in accordance with conventional techniques.(5,6)

Panorama atual da ética em pesquisa em seres humanos

In the last decades, medical care has been increasingly permeated by the concept of evidence-based-medicine, in which clinical research plays a crucial role in establishing diagnostic and treatment. Following the improvements in clinical research, we have a growing concern and understanding that some ethical issues must be respected when the subjects are human beings. Research with human subjects relies on the principles of autonomy, beneficence, no maleficence and justice. Ordinance 196/96 from the National Health Board adds to the Brazilian legislation such renowned bioethical principles.Aim: Discuss the main ethical aspects involved in research with human subjects.Materials and Methods: Critical analysis of Ordinance 196/96 and related literature.Conclusion: Ordinance 196/96 rules research with human subjects; nevertheless, it requires more in-depth discussions regarding the informed consent, use of placebo, research with vulnerable populations and research in developing countries.

Effect of posture-control insoles on function in children with cerebral palsy: Randomized controlled clinical trial

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Tempo de latencia do rocuronio e da succinilcolina e condicoes de intubacao traqueal

Background and Objectives - Pulmonary aspiration of gastric content during induction of anesthesia for emergency surgical procedures is a serious complication; fast endotracheal intubation under these circumstances is of vital importance to secure the airways. Despite its numerous side effects, succinylcholine is used for this purpose. Rocuronium is the most recently introduced aminoesteroid neuromuscular blocking drug with short onset. The objective of this study was to compare the onset time and intubating conditions of rocuronium and succinylcholine. Methods - After informed consent, forty-five patients were randomly allocated into three groups of 15: Group I (GI) = succinylcholine 1 mg.kg-1; Group II (GII) = rocuronium 0.6 mg.kg-1; Group III (GIII) = rocuronium 0.9 mg.kg-1. Every patient was premedicated with midazolam 15 mg per os and induction of anesthesia was made with fentanyl 10 μg.kg-1 and etomidate 0.3 mg.kg-1. The neuromuscular block was monitored with the TOP-Guard neuromuscular transmission monitor. The TOP-Guard neuromuscular monitor uses an accelerometer to measure the response to nerve stimulation. The stimulating electrodes were placed close to the course of the ulnar nerve at the wrist. The onset time was considered as the time between the end of neuromuscular drug injection and the twitch height (T1) decrease to 10%. Heart rate and arterial blood pressure were registered at 6 moments before and after induction of anesthesia. Results - The onset time results were: Group I, 71 s; Group II, 120 s and Group III, 70 s or GI = GIII < GII (F = 8.862; p < 0.01). There were 43 patients exhibiting excellent intubating conditions and 2 with good intubating conditions. Heart rate and arterial blood pressure showed alterations due to induction of anesthesia and intubation. Conclusions - Rocuronium 0.9 mg.kg-1 can be used in rapid sequence induction because it has a short onset time which is similar to that of succnylcholine. It is likely that rocuronium would be a good indication in patients with high intracranial pressure, burns and neuromuscular diseases.

A identidade do agente comunitário de saúde: Uma abordagem fenomenológica

The structure of Brazil's National Health System (SUS) is being firmed up through programs adding a new element to its multi-professional healthcare teams: Community Healthcare Agents. This study examines psycho-social factors that are significant for the construction of this identity, from the standpoint of these Community Healthcare Agents, using the hermeneutic phenomenology of Paul Ricoeur as its reference methodology. The subjects of this survey were seven Community Healthcare Agents who were asked during interviews (with informed consent and after approval by the Research Ethics Committee) to: 'Tell me about your experience as Community Healthcare Agent'. The analysis of their replies indicated the following topics: previous experience; capacity-building for the job; bonding; building up expertise; gratifying experience; feelings of power(lessness); communications; daily work routines, personal growth; criticisms of the institution; user-agent experiences; and insertion into the social reality. The overall analysis disclosed the phenomenon through the convergence and divergence of the grouping of these topics, viewed from the standpoint of these Community Healthcare Agents and the psycho-social aspects constructing their identity.

Committees for ethics in research involving human subjects

In Brazil since October 1996 there have been guidelines for research involving human subjects. Now human subjects know when their treatment is part of research. Deceit is no longer tolerated. But is not enough to say we offer an explanation to the potential subject and we offer a choice before he or she is confronted with an informed consent form. As in all professional activity, scientific investigation needs social controls. In Brazil, the ultimate responsibility of an investigation lies on the investigator, but in every institution where research is carried out there is a Committee for Ethics in Research. All Committees are subordinated to the National Commission of Ethics in Research, which is submitted to the Brazilian Institute of Health. During 2005 around 17,000 protocols involving 700,000 human subjects were revised by 475 Committees distributed all over the country. Approximately 7,000 people are now working in these Committees.

Polimorfismo nos genes metilenotetrahidrofolato redutase e cistationina-beta-sintase e a sua relação com eventos vaso-oclusivos na doença falciforme

Sickle cell disease is an inflammatory condition with a pathophysiology that involves vaso-occlusive episodes. Mutations of the methylenetetrahydrofolate reductase (MTHFR) and cystathionine beta-synthase (CBS) genes are risk factors for vascular disease. Due to the importance of identifying risk factors for vaso-occlusive events in sickle cell patients, we investigated the frequencies of the C677T and 844ins68 mutations of the MTHFR and CBS genes, respectively. Three hundred patients with Hb SS, HB SC and HbS/Beta thalassemia, from Brasília, Goiânia, Rio de Janeiro, São Jose do Rio Preto and São Paulo were evaluated. Samples of 5 mL of venous blood were collected in EDTA after informed consent was received from patients. Classical diagnostic methods were used to confirm the hemoglobin phenotypes. The hemoglobin genotypes and polymorphisms studied were evaluated by Restriction Fragment Length Polymorphism and Allele Specific amplification. The results showed that 93 patients (31.00%) were heterozygous and 13 (4.33%) homozygous for the C677T mutation and 90 were heterozygotes (30.00%) and 8 homozygous (2.66%) for the 844ins68 mutation, both with significant differences for genotype frequency between the localities. The allelic frequencies are in Hardy-Weinberg equilibrium for both polymorphisms. The frequency of mutations was significant and the presence of related vaso-occlusive events was more common in patients with Hb SS (p = 0007). The 844ins68 mutation was approximately three times more frequent in patients with vaso-occlusive complications (p = 0011). The C677T mutation did not prove to be associated with risk of vaso-occlusive events (p = 0.193). A C677T-844ins68 interaction occurred in 12.08% of the patients, doubling the risk of vaso-occlusive manifestations. The frequencies of the polymorphisms are consistent with those expected in the Brazilian population. The presence of the 844ins68 mutation of the CBS gene proved to be a potential risk factor for vaso-occlusive events in sickle cell patients.