Performance in vitro of apex locators in determining root length in primary molars / Desempenho in vitro de localizadores apicais na determinação de comprimento radicular em molares decíduos

ABSTRACT Objective: The aim of the study was to evaluate performance of digital radiographic and two electronic apex locators, Propex II and Root ZX in root canal length determination in primary molars. Methods: 25 primary molars were divided into two groups, G1 without root resorption and G2 with root resorption. The exams were performed using all methods by two experienced examiners, with 1-week interval. The gold standard was determined by visual examination. The methods were statistically analyzed regarding the values of reproducibility and correlated with the gold standard by Pearson´s correlation coefficient. Results: The root canal length determination coincided with gold standard in 22.7% for Root ZX, 17.5% for Propex II and 12.5% for digital radiography. Correlation values were higher in G1, the Root ZX presented the highest values. In G2 the digital radiography showed the lowest correlation. In G1, the intra-examiner reproducibility values ranged from 0.925 to 0.523, and interexaminer 0.863 to 0.670. In G2, the values of intra-examiner reproducibility ranges from 0.864 to 0.097, and inter was 0.774 to 0.379. Conclusion: It was concluded that the methods performance varying according to examiner's experience. The Root ZX presented the highest reproducibility and accuracy.

RESUMO Objetivo: Avaliar o desempenho in vitro de radiografia digital e de dois localizadores apicais eletrônicos, Propex II e Root ZX na determinação do comprimento de canal em molares decíduos. Métodos: Foram selecionados 25 molares decíduos divididos em dois grupos, G1, sem reabsorção radicular e G2 com reabsorção radicular. Os exames foram realizados utilizando todos os métodos por dois examinadores experientes, com intervalo de 1 semana. O padrão ouro foi determinada por exame visual. Os métodos foram analisados estatisticamente em relação aos valores de reprodutibilidade e correlacionada com o padrão ouro pelo coeficiente de correlação de Pearson. Resultados: A determinação de comprimento de canal coincidiu com padrão-ouro em 22,7% para o Root ZX, 17,5% para Propex II e 12,5% para a radiografia digital. valores de correlação foram maiores no G1, o Root ZX apresentou os maiores valores. Em G2 da radiografia digital apresentou a menor correlação. No G1, os valores de reprodutibilidade intra-examinador variou 0,925-0,523 e interexaminadores 0,863-0,670. No G2, os valores da reprodutibilidade intra-examinador varia 0,864-0,097, e inter era 0,774-0,379. Conclusão: Concluiu-se que o desempenho dos métodos varia de acordo com a experiência do examinador. O Root ZX apresentou maior reprodutibilidade e precisão.

Novel transcripts in the maxillary venom glands of advanced snakes.

Venom proteins are added to reptile venoms through duplication of a body protein gene, with the duplicate tissue-specifically expressed in the venom gland. Molecular scaffolds are recruited from a wide range of tissues and with a similar level of diversity of ancestral activity. Transcriptome studies have proven an effective and efficient tool for the discovery of novel toxin scaffolds. In this study, we applied venom gland transcriptomics to a wide taxonomical diversity of advanced snakes and recovered transcripts encoding three novel protein scaffold types lacking sequence homology to any previously characterised snake toxin type: lipocalin, phospholipase A2 (type IIE) and vitelline membrane outer layer protein. In addition, the first snake maxillary venom gland isoforms were sequenced of ribonuclease, which was only recently sequenced from lizard mandibular venom glands. Further, novel isoforms were also recovered for the only recently characterised veficolin toxin class also shared between lizard and snake venoms. The additional complexity of snake venoms has important implications not only for understanding their molecular evolution, but also reinforces the tremendous importance of venoms as a diverse bio-resource.

Venomics profiling of Thamnodynastes strigatus unveils matrix metalloproteinases and other novel proteins recruited to the toxin arsenal of rear-fanged snakes.

Rear-fanged and aglyphous snakes are usually considered not dangerous to humans because of their limited capacity of injecting venom. Therefore, only a few studies have been dedicated to characterizing the venom of the largest parcel of snake fauna. Here, we investigated the venom proteome of the rear-fanged snake Thamnodynastes strigatus , in combination with a transcriptomic evaluation of the venom gland. About 60% of all transcripts code for putative venom components. A striking finding is that the most abundant type of transcript (∼47%) and also the major protein type in the venom correspond to a new kind of matrix metalloproteinase (MMP) that is unrelated to the classical snake venom metalloproteinases found in all snake families. These enzymes were recently suggested as possible venom components, and we show here that they are proteolytically active and probably recruited to venom from a MMP-9 ancestor. Other unusual proteins were suggested to be venom components: a protein related to lactadherin and an EGF repeat-containing transcript. Despite these unusual molecules, seven toxin classes commonly found in typical venomous snakes are also present in the venom. These results support the evidence that the arsenals of these snakes are very diverse and harbor new types of biologically important molecules.