Making DNA without iron: induction of a manganese-dependent ribonucleotide reductase in response to iron starvation

Ribonucleotide reductases supply cells with their deoxyribonucleotides. Three enzyme types are known, classes I, II and III. Class II enzymes are anaerobic whereas class I enzymes are aerobic, and so class I and II enzymes are often produced by the same organism under opposing oxygen regimes. Escherichia coli contains two types of class I enzyme (Ia and Ib) with the Fe-dependent Ia enzyme (NrdAB) performing the major role aerobically, leaving the purpose of the Ib enzyme (NrdEF) unclear. Several papers have recently focused on the class Ib enzymes showing that they are Mn (rather than Fe) dependent and suggesting that the E. coli NrdEF may function under redox-stress conditions. A paper published in this issue of Molecular Microbiology from James Imlay's group confirms that this unexplained NrdEF Ib enzyme is Mn-dependent, but shows that it does not substitute for NrdAB during redox stress. Instead, a role during iron restriction is demonstrated. Thus, the purpose of NrdEF (and possibly other class Ib enzymes) is to enhance growth under aerobic, low-iron conditions, and to functionally replace the Fe-dependent NrdAB when iron is unavailable. This finding reveals a new mechanism by which bacteria adjust to life under iron deprivation.

Prevalência de oclusopatias e caracteríticas cefalométricas e dentais de escolares cearense da cidade de Fortaleza

The people of Ceará state are descended from miscegenation between the Portuguese colonizers and the native population, resulting in a different facial pattern from other populations. It is important that this pattern be thoroughly understood, along with its minimum and maximum values so that they can be assessed and respected, allowing professionals who deal with the craniofacial complex to work more efficiently and scientifically. Aim: To characterize the morphological pattern of individuals from Ceará state, whose father and grandfather are also native from Ceará, in the 10-12 year age group, not submitted to previous orthodontic treatment, in order to determine: 1) the prevalence of occlusal pattern; 2) the prevalence of dental anomalies (DA) and, 3) the skeletal and dental cephalometric characteristics of individuals that present with normal occlusion and harmonious facial pattern. Methodology: A list of 10-12 year-olds was obtained from 515 schools containing 162,713 students (Education Secretariat of Ceará State), from which 234 individuals were examined (107 boys and 157 girls). The assessment criteria adopted were: 1) Angle s Classification System to determine occlusal pattern. The occlusal characteristics were measured through overbite, overjet, crowding and interincisal diastema. 2) DA are anomalies of number, shape, size, eruption and structure and, 3) in the group that presented with normal occlusion, we used cephalometric analysis measures proposed by Downs, Steiner, Tweed, Holdaway, Jacobson and McNamara. Results: 1) 25.8% of the schoolchildren had normal occlusion, 47.5% class I malocclusion, 22.3% class II malocclusion and 4.2% class III malocclusion. No statistically significant difference was found between the age group studied and sex. Thirty percent of the individuals had normal overbite, while 36.7% and 19.7% had increased and reduced overbite, respectively. Normal overjet was found in 33.7% of the individuals, increased overjet in 50% and reduced in 16.3%. Dental crowding was observed in 62.5% of the individuals and the presence of interincisal diastema in 14.8%. 2) The prevalence of DA was 56.1%, 6.8% in the number, 10.8% in shape, 4.1% in size, 34.5% in eruption, 26.4% in structure and 17.4% had more than one DA. No association was found between DA and sex, but DA was significantly associated to malocclusion (p<0.05); 3) there was no association between sex or facial type between the measures of nasal-labial angle, position and effective maxillary length, effective mandibular length and the sagittal relationship between the molars, overjet and overbite, position of upper incisors, lower incisors and between the incisors themselves. There was a difference between sex, on the VERT index and in lower anterior facial height, upper incisor inclination and line-H, between facial types for the occlusal plane angles, mandibular plane, facial axis, lower incisor inclination, mandibular position, upper incisor position, lower anterior facial height, ANB and line-H. It was concluded that: 1) the most prevalent occlusal type was class I malocclusion, with no distinction for sex or age group, and the assessment of occlusal characteristics showed that excessive overbite and overjet were the most predominant findings, along with a high occurrence of tooth crowding; 2) a high prevalence of DA was found, particularly eruption anomalies, not influenced by sex but significantly associated to malocclusion and 3) individuals from Ceará are predominantly brachyfacial, exhibiting a number of similarities inherent to their facial pattern, such as a convex profile, retracted jaw, reduced lower third and protruded lower incisors. This study was multidisciplinary, involving researchers from the areas of epidemiology, radiology and dentistry, thereby meeting the multidisciplinarity requirements of the Postgraduate Program in Health Sciences

Prevalence of removable partial dentures users treated at the Aracatuba Dental School - UNESP

Objectives: The aim of this study was to evaluate the frequency of removable partial dentures (RPD) at the Aracatuba Dental School.Methods: The study was conducted by analysing 412 clinical history of patients attended at the RPD clinics in the period from 2000 to 2007.Results: 412 charts were analysed: 148 (35.9%) men and 264 (64.1%) women. The mean age was 53.8 years (men) and 52.4 years (women). A total of 556 dentures were made; of these, 233 (41.90%) were maxillary and 323 (58.09%) were mandibular dentures. The most frequent Kennedy classification found was Class III (maxilla) and Class I (mandible). In the maxilla, 55% (126) of the major connectors were of the anterior-posterior palatal bar, while in the mandible, 64% (202) were the lingual bar. As regards the claps, 401 were circumferential and 318 were bar claps.Conclusion: The mean age of the patients was 52.9 years with higher prevalence of female patients; the most frequent Kennedy's classification was Class I in mandible and Class III in maxilla; the most common major connector was anterior-posterior palatal bar for maxilla and lingual bar for mandible; the circumferential clasps were the most common retainer used in both jaws.

Morphology of the sternal gland in workers of Coptotermes gestroi (Isoptera, Rhinotermitidae)

The sternal gland is considered the only source of trail pheromones in termites. The morphology of the sternal gland was investigated in workers of Coptotermes gestroi using transmission and scanning electron microscopy. The results showed a small bilobed gland at the anterior part of the fifth abdominal sternite. The cuticular surface of the sternal gland showed a V-shaped structure with two peg sensilla in elevated socket and various campaniform sensilla. Pores and cuticular scale-like protuberances also occur in the glandular area. The ultrastructure showed a gland composed of class I cells and two different types of class 3 cells distinguished by location, different size and electron-density of secretory vesicles. Small class 3 cells (type 1) of the anterior lobe are inserted among class I cells and have weakly electron-dense vesicles associated with mitochondria, glycogen and smooth endoplasmic reticulum. The class 3 cells (type 2) of posterior lobe showed many round electron-lucent vesicles of secretion, abundant free ribosomes and a well-developed Golgi apparatus. Each class 3 cell is connected to the cuticle by a cuticular duct constituted by the receiving canal and the conducting canal. The secretion of class I cells is stored in an inner subcuticular reservoir that is delimited by the microvilli of these cells. This inner reservoir is large and crossed by the campaniform sensilla and ducts of two types of class 3 cells that open outside of the insect body. An exterior reservoir also is present between the fourth and fifth sternite. The complex structure of the sternal gland suggests multicomponents for the trail pheromone in the worker of C gestroi. (c) 2005 Elsevier Ltd. All rights reserved.

Early cephalometric characteristics in Class III malocclusion

OBJECTIVE: Early identification of craniofacial morphological characteristics allows orthopedic segmented interventions to attenuate dentoskeletal discrepancies, which may be partially disguised by natural dental compensation. To investigate the morphological characteristics of Brazilian children with Class III malocclusion, in stages I and II of cervical vertebrae maturation and compare them with the characteristics of Class I control patients. METHODS: Pre-orthodontic treatment records of 20 patients with Class III malocclusion and 20 control Class I patients, matched by the same skeletal maturity index and sex, were selected. The craniofacial structures and their relationships were divided into different categories for analysis. Angular and linear measures were adopted from the analyses previously described by Downs, Jarabak, Jacobson and McNamara. The differences found between the groups of Class III patients and Class I control group, both subdivided according to the stage of cervical vertebrae maturation (I or II), were assessed by analysis of variance (ANOVA), complemented by Bonferroni's multiple mean comparisons test. RESULTS: The analysis of variance showed statistically significant differences in the different studied groups, between the mean values found for some angular (SNA, SNB, ANB) and linear variables (Co - Gn, N - Perp Pog, Go - Me, Wits, S - Go, Ar - Go). CONCLUSION: Assessed children displaying Class III malocclusion show normal anterior base of skull and maxilla, and anterior positioning of the mandible partially related to increased posterior facial height with consequent mandibular counterclockwise rotation.

Estudo cefalométrico das alturas faciais anterior e posterior, em crianças brasileiras, portadoras de má oclusão Classe I de Angle, na fase de dentadura mista

Realizou-se um estudo das alturas faciais anterior e posterior em 79 crianças brasileiras, sendo 46 do gênero feminino e 33 do masculino, com idades de 8 a 11 anos, portadoras de má oclusão Classe I de Angle, na fase de dentadura mista, não submetidas a tratamento ortodôntico. Esta investigação utilizou duas radiografias cefalométricas em norma lateral, de cada criança, com intervalo de 8 a 16 meses entre uma radiografia e outra, para comparação dos dados cefalométricos. Foram estudadas as proporções faciais anteriores, ou seja, a relação entre as dimensões N-Me (AFT), N-ENA (AFS), ENA-Me (AFI) e o relacionamento entre as dimensões Ar-GO (AFP) e a distância entre o plano palatino ao mento (AFA) , isto é, o Índice da Altura Facial (IAF). Os resultados obtidos, possibilitaram constatar que as tendências de crescimento foram equilibradas em todas as situações estudadas; a dimensão altura facial inferior, contribuiu de forma mais significativa, nas alterações observadas na altura facial total; as proporções faciais anteriores se mantiveram em torno de 42% para a altura facial superior e 58% para a altura facial inferior; o índice da altura facial ou se manteve constante em torno de 0,66 ou apresentou uma tendência a aumentar com a idade; não ocorreu dimorfismo sexual com relação às proporções faciais e índice da altura facial.

Oral myofunctional and electromyographic evaluation of the anterior suprahyoid muscles and tongue thrust in patients with class II/1 malocclusion submitted to first premolar extraction

Objective: The aim of this study was to assess the existence of myofunctional alterations before and after first premolar extraction in Class II/1 malocclusion patients that could endanger the long-term dental arch stability. Materials and Methods: The study was performed by means of morphological, functional and electromyographic analyses in 17 Class II/1 malocclusion patients (group T) and 17 Class I malocclusion patients (group C), both groups with 12-30-year age range (mean age: 20.93 ± 4.94 years). Results: Data analyzed statistically by Student's t-test showed a significant decrease in the maxillary and mandibular dental arch perimeters after orthodontic treatment (p<0.05). The Kruskal-Wallis test analyzed data from tongue posture at rest and during swallowing, not showing significant differences after treatment (groups Tb and Ta) (p>0.05). However, group T differed significantly from group C (p<0.05). The electromyographic data showed that the anterior right and left suprahyoid muscles acted synergistically in both groups, while having a lower myoelectric activity in group T during swallowing. Conclusions: Myofunctional alterations observed after the orthodontic treatment in Class II/1 malocclusion seemed to jeopardize the long-term orthodontic stability, making recurrence possible. Further research should be conducted to compare electromyographic data before and after orthodontic treatment in order to corroborate the results of the present investigation.

Structure of a novel class II phospholipase D: Catalytic cleft is modified by a disulphide bridge

Phospholipases D (PLDs) are principally responsible for the local and systemic effects of Loxosceles envenomation including dermonecrosis and hemolysis. Despite their clinical relevance in loxoscelism, to date, only the SMase I from Loxosceles laeta, a class I member, has been structurally characterized. The crystal structure of a class II member from Loxosceles intermedia venom has been determined at 1.7. Å resolution. Structural comparison to the class I member showed that the presence of an additional disulphide bridge which links the catalytic loop to the flexible loop significantly changes the volume and shape of the catalytic cleft. An examination of the crystal structures of PLD homologues in the presence of low molecular weight compounds at their active sites suggests the existence of a ligand-dependent rotamer conformation of the highly conserved residue Trp230 (equivalent to Trp192 in the glycerophosphodiester phosphodiesterase from Thermus thermophofilus, PDB code: 1VD6) indicating its role in substrate binding in both enzymes. Sequence and structural analyses suggest that the reduced sphingomyelinase activity observed in some class IIb PLDs is probably due to point mutations which lead to a different substrate preference. © 2011 Elsevier Inc.

Características morfológicas dentoesqueléticas das más oclusões de classe I, classe II e classe II subdivisão

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Ruídos articulares em pacientes parcialmente desdentados (classe I ou II de Kennedy), antes e após a reposição dental com prótese parcial removível: avaliação através da eletrovibratografia

Pós-graduação em Odontologia - FOA

Influência dos sistemas de retenção e da inclinação do rebordo residual em casos de próteses conjugadas Classe I mandibular: análise da distribuição das tensões pelo método da fotoelasticidade

Pós-graduação em Odontologia - FOA

Análise histopatológica comparativa de polpas humanas após confecção de cavidades de classe I com turbina de alta velocidade ou laser de Er:YAG

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Estratigrafia de seqüências do Grupo Itararé (Neocarbonifero-Eopermiano) na região de Rio Negro (PR) - Mafra (SC)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Angulação dos caninos em indivíduos portadores de má oclusão de Classe I e de Classe III: análise comparativa através de um novo método utilizando imagens digitalizadas

OBJETIVO: determinar as angulações mesiodistais das coroas dos caninos em indivíduos portadores de má oclusão de Classe III, comparando-os a indivíduos Classe I. MÉTODOS: foram empregadas medidas tomadas em fotografias digitalizadas de modelos de gesso e transportadas para um programa gráfico para leitura das medidas (Image Tool). Tais procedimentos foram repetidos para avaliação do erro do método casual (fórmula de Dahlberg) e para a análise da reprodutibilidade através da Correlação intraclasse. A amostra constituiu-se de 57 pacientes com dentição permanente completa e não tratados ortodonticamente, dividida em dois grupos, de acordo com a má oclusão apresentada: o grupo I foi constituído por 33 pacientes portadores de má oclusão de Classe I, sendo 16 do sexo masculino e 17 do feminino, com média de idades de 27 anos; o grupo II era representado por 24 pacientes portadores de má oclusão de Classe III, 20 do sexo masculino e 4 do feminino, com média de idades de 22 anos. RESULTADOS: o erro casual mostrou-se com uma variação de 1,54 a 1,96 graus para a angulação dos caninos. A análise estatística revelou que o método apresenta uma excelente reprodutibilidade (p<0,01). Os resultados obtidos na angulação da coroa dos caninos não mostraram diferença estatisticamente significativa entre os caninos superiores nos grupos Classe I e Classe III, embora esse dente mostrasse, em média, uma angulação 2 graus maior nos indivíduos Classe III. Entretanto, para os caninos inferiores, foi observada uma diferença estatisticamente significativa em ambos os lados (p=0,0009 e p=0,0074) entre os grupos Classe I e Classe III. Os pacientes Classe III apresentaram uma menor angulação nos caninos inferiores em comparação aos pacientes Classe I, tendendo a acompanhar a compensação natural dos incisivos, descrita rotineiramente na literatura. CONCLUSÃO: os resultados permitem concluir que as compensações dentárias, frequentemente observadas na literatura para a região de incisivos, se estendem também à angulação dos caninos, principalmente no que se refere à arcada inferior.

Avaliação clínica da sensibilidade pós-operatória em restaurações oclusais com 3 sistemas adesivos: 3 passos (Scotchbond MP Plus), 2 passos associado a dessensibilizante (Gluma Confort Bond + Dessensitizer) e de 1 passo-auto-condicionante simplificado (I Bond)

O objetivo desse estudo foi analisar clinicamente o comportamento de 60 restaurações oclusais, em relação à sensibilidade pós-operatória em cavidades oclusais em pré-molares e molares. Foram selecionados dentes considerados dentro da normalidade, após testes clínicos e radiográficos, onde cavidades de média profundidade e largura máxima de ½ da distancia entre os vértices de cúspides na área do istmo, eram requeridas. A profundidade da parede pulpar foi estabelecida em dentina pelo menos 1 mm além da junção amelodentinária. Os detalhes do preparo foram registrados por fotografia (digitalizadas), por moldagem com silicone de condensação, modelos de gesso. Esses cuidados foram tomados para que futuramente servissem como auxiliar de interpretação de resultados. As restaurações foram feitas sob isolamento absoluto, para evitarmos contaminação pela saliva e sangue. Em 20 preparos foram feitos procedimentos restauradores com sistema de 3 passos (Scotchbond MP Plus). Em outros 20 preparos foram feitos procedimentos restauradores com sistema de 2 passos associado a dessensibilizantes (Gluma Confort Bond + Dessensitizer). Em outros 20 preparos foram feitos procedimentos restauradores com sistema de 1 passo autocondicionante simplificado (I Bond). Os 60 dentes foram restaurados com a resina composta Filtek Supreme, por ser um material apropriado para dentes posteriores, por meio da técnica incremental. Após 48 horas e 7 dias os pacientes retornavam para o controle da sensibilidade pós-operatória. Inicialmente era obtido um relato do paciente, para em seguida serem realizados testes clínicos (térmico, pressão e percussão). Os dados foram tabelados e os resultados analisados. Não houve diferença na sensibilidade antes e após (48 horas e 7 dias) a colocação das restaurações para todos os grupos.