Reduced genetic diversity and the success of the invasive peacock bass (Cichliformes: Cichlidae)

Abstract Several species of Cichla successfully colonized lakes and reservoirs of Brazil, since the 1960s, causing serious damage to local wildlife. In this study, 135 peacock bass were collected in a reservoir complex in order to identify if they represented a single dominant species or multiple ones, as several Cichla species have been reported in the basin. Specimens were identified by color pattern, morphometric and meristic data, and using mitochondrial markers COI, 16S rDNA and Control Region (CR). Overlapping morphological data and similar coloration patterns prevented their identification using the taxonomic keys to species identification available in the literature. However, Bayesian and maximum likelihood from sequencing data demonstrated the occurrence of a single species, Cichla kelberi. A single haplotype was observed for the 16S and CR, while three were detected for COI, with a dominant haplotype present in 98.5% of the samples. The extreme low diversity of the transplanted C. kelberi evidenced a limited number of founding maternal lineages. The success of this colonization seems to rely mainly on abiotic factors, such as increased water transparency of lentic environments that favor visual predators that along with the absence of predators, have made C. kelberi a successful invader of these reservoirs.

Resumo Muitas espécies de Cichla colonizaram com sucesso lagos e reservatórios do Brasil desde os anos 1960, causando graves prejuízos à vida selvagem nesses locais. Neste estudo, 135 tucunarés foram coletados em um complexo de reservatórios a fim de identificar se representavam uma espécie dominante ou múltiplas espécies, uma vez que diversas espécies de Cichla foram registradas na bacia. Os espécimes foram identificados com base na coloração, dados morfométricos e merísticos, e por marcadores mitocondriais COI, 16S rDNA e Região Controle (RC). A sobreposição dos dados morfométricos e o padrão similar de coloração impediram a identificação utilizando as chaves de identificação disponíveis na literatura. Entretanto, as análises bayesiana e de máxima verossimilhança de dados moleculares demonstraram a ocorrência de uma única espécie, Cichla kelberi. Um único haplótipo foi observado para o 16S e RC, enquanto três foram detectados para o COI, com um haplótipo dominante presente em 98,5% das amostras. A baixa diversidade nos exemplares introduzidos de C. kelberi evidenciou um número limitado de linhagens maternas fundadoras. O sucesso da invasão parece depender de fatores abióticos, como a maior transparência da água de ambientes lênticos que favorece predadores visuais que, atrelado à ausência de predadores, fez do C. kelberi um invasor bem-sucedido nesses reservatórios.

Reduced genetic diversity and the success of the invasive peacock bass (Cichliformes: Cichlidae) / Diversidade genética reduzida e o sucesso da espécie invasora tucunaré (Cichliformes: Cichlidae)

Abstract Several species of Cichla successfully colonized lakes and reservoirs of Brazil, since the 1960's, causing serious damage to local wildlife. In this study, 135 peacock bass were collected in a reservoir complex in order to identify if they represented a single dominant species or multiple ones, as several Cichla species have been reported in the basin. Specimens were identified by color pattern, morphometric and meristic data, and using mitochondrial markers COI, 16S rDNA and Control Region (CR). Overlapping morphological data and similar coloration patterns prevented their identification using the taxonomic keys to species identification available in the literature. However, Bayesian and maximum likelihood from sequencing data demonstrated the occurrence of a single species, Cichla kelberi. A single haplotype was observed for the 16S and CR, while three were detected for COI, with a dominant haplotype present in 98.5% of the samples. The extreme low diversity of the transplanted C. kelberi evidenced a limited number of founding maternal lineages. The success of this colonization seems to rely mainly on abiotic factors, such as increased water transparency of lentic environments that favor visual predators that along with the absence of predators, have made C. kelberi a successful invader of these reservoirs.

Resumo Muitas espécies de Cichla colonizaram com sucesso lagos e reservatórios do Brasil desde os anos 1960, causando graves prejuízos à vida selvagem nesses locais. Neste estudo, 135 tucunarés foram coletados em um complexo de reservatórios a fim de identificar se representavam uma espécie dominante ou múltiplas espécies, uma vez que diversas espécies de Cichla foram registradas na bacia. Os espécimes foram identificados com base na coloração, dados morfométricos e merísticos, e por marcadores mitocondriais COI, 16S rDNA e Região Controle (RC). A sobreposição dos dados morfométricos e o padrão similar de coloração impediram a identificação utilizando as chaves de identificação disponíveis na literatura. Entretanto, as análises bayesiana e de máxima verossimilhança de dados moleculares demonstraram a ocorrência de uma única espécie, Cichla kelberi. Um único haplótipo foi observado para o 16S e RC, enquanto três foram detectados para o COI, com um haplótipo dominante presente em 98,5% das amostras. A baixa diversidade nos exemplares introduzidos de C. kelberi evidenciou um número limitado de linhagens maternas fundadoras. O sucesso da invasão parece depender de fatores abióticos, como a maior transparência da água de ambientes lênticos que favorece predadores visuais que, atrelado à ausência de predadores, fez do C. kelberi um invasor bem-sucedido nesses reservatórios.

Reduced genetic diversity and the success of the invasive peacock bass (Cichliformes: Cichlidae).

Several species of Cichla successfully colonized lakes and reservoirs of Brazil, since the 1960's, causing serious damage to local wildlife. In this study, 135 peacock bass were collected in a reservoir complex in order to identify if they represented a single dominant species or multiple ones, as several Cichla species have been reported in the basin. Specimens were identified by color pattern, morphometric and meristic data, and using mitochondrial markers COI, 16S rDNA and Control Region (CR). Overlapping morphological data and similar coloration patterns prevented their identification using the taxonomic keys to species identification available in the literature. However, Bayesian and maximum likelihood from sequencing data demonstrated the occurrence of a single species, Cichla kelberi. A single haplotype was observed for the 16S and CR, while three were detected for COI, with a dominant haplotype present in 98.5% of the samples. The extreme low diversity of the transplanted C. kelberi evidenced a limited number of founding maternal lineages. The success of this colonization seems to rely mainly on abiotic factors, such as increased water transparency of lentic environments that favor visual predators that along with the absence of predators, have made C. kelberi a successful invader of these reservoirs.

Description of the methodology for dosimetric quantification in treatments with 177Lu-DOTATATE. / Descripción de la metodología para la cuantificación dosimétrica en tratamientos con 177Lu-DOTATATE.

Implementation of dosimetry calculations in the daily practice of Nuclear Medicine Departments is, at this time, a controversial issue, partly due to the lack of a standardized methodology that is accepted by all interested parties (patients, nuclear medicine physicians and medical physicists). However, since the publication of RD 601/2019 there is a legal obligation to implement it, despite the fact that it is a complex and high resource consumption procedure. The aim of this article is to review the theoretical bases of in vivo dosimetry in treatments with 177Lu-DOTATATE. The exposed methodology is the one proposed by the MIRD Committee (Medical Internal Radiation Dose) of the SNMMI (Society of Nuclear Medicine & Molecular Imaging). According to this method, the absorbed dose is obtained as the product of 2factors: the time-integrated activity of the radiopharmaceutical present in a source region and a geometrical factor S. This approach, which a priori seems simple, in practice requires several SPECT/CT acquisitions, several measurements of the whole body activity and taking several blood samples, as well as hours of image processing and computation. The systematic implementation of these calculations, in all the patients we treat, will allow us to obtain homogeneous data to correlate the absorbed doses in the lesions with the biological effect of the treatment. The final purpose of the dosimetry calculations is to be able to maximize the therapeutic effect in the lesions, controlling the radiotoxicity in the organs at risk.

Effects of seasonality on drosophilids (Insecta, Diptera) in the northern part of the Atlantic Forest, Brazil.

Seasonality is an important aspect associated with population dynamic and structure of tropical insect assemblages. This study evaluated the effects of seasonality on abundance, richness, diversity and composition of an insect group, drosophilids, including species native to the Neotropical region and exotic ones. Three preserved fragments of the northern Atlantic Forest were surveyed, where temperatures are above 20 °C throughout the year and rainfall regimes define two seasons (dry and rainy). As opposed to other studies about arthropods in tropical regions, we observed that abundance of drosophilids was significantly higher in the dry season, possibly due to biological aspects and the colonization strategy adopted by the exotic species in these environments. Contrarily to abundance, we did not observe a seasonal pattern for richness. As for other parts of the Atlantic Forest, the most representative Neotropical species (Drosophila willistoni, D. sturtevanti, D. paulistorum and D. prosaltans) were significantly more abundant in the rainy season. Among the most abundant exotic species, D. malerkotliana, Zaprionus indianus and Scaptodrosophila latifasciaeformis were more importantly represented the dry season, while D. simulans was more abundant in the rainy period. The seasonality patterns exhibited by the most abundant species were compared to findings published in other studies. Our results indicate that exotic species were significantly more abundant in the dry season, while native ones exhibited an opposite pattern.

Contributions of Dryland Forest (Caatinga) to Species Composition, Richness and Diversity of Drosophilidae.

In this study, semi-arid environments were tested to see if they support insect diversity. This was evaluated through the structure of the composition of assemblies of drosophilids in three conservation units placed in three different ecoregions in the dryland forests, Caatinga. This is a unique biome in northeast Brazil, comprising approximately 10% of the country. Species richness was investigated over 2 years during a prolonged drought, considered the worst affliction the Caatinga ecosystem had experienced in the last 50 years. Alpha diversity indices and the ecological similarity between the samples were calculated to determine how the environments drive the composition of Drosophilidae in such semi-arid places. A total of 7352 specimens were sampled. They were classified into 20 species belonging to four genera: Drosophila, Rhinoleucophenga, Scaptodrosophila, and Zaprionus. Drosophila nebulosa Sturtevant (44.5%) and Drosophila cardini Sturtevant (12.5%) were the most abundant species. The occurrences and abundances of all the species differed greatly between sites. These results and other ecological analyses indicate that although placed in the same biome, there are great variability in the drosophilid species and abundance among the three protected and conserved dryland environments.

Sphingomyelin derivatives increase the frequency of microvesicle and granule fusion in chromaffin cells.

Sphingomyelin derivatives like sphingosine have been shown to enhance secretion in a variety of systems, including neuroendocrine and neuronal cells. By studying the mechanisms underlying this effect, we demonstrate here that sphingomyelin rafts co-localize strongly with synaptosomal-associated protein of 25Kda (SNAP-25) clusters in cultured bovine chromaffin cells and that they appear to be linked in a dynamic manner. In functional terms, when cultured rat chromaffin cells are treated with sphingomyelinase (SMase), producing sphingomyelin derivatives, the secretion elicited by repetitive depolarizations is enhanced. This increase was independent of cell size and it was significant 15min after initiating stimulation. Interestingly, by evaluating the membrane capacitance we found that the events in control untreated cells corresponded to two populations of microvesicles and granules, and the fusion of both these populations is clearly enhanced after treatment with SMase. Furthermore, SMase does not increase the size of chromaffin granules. Together, these results strongly suggest that SNARE-mediated exocytosis is enhanced by the generation of SMase derivatives, reflecting an increase in the frequency of fusion of both microvesicles and chromaffin granules rather than an increase in the size of these vesicles.

Resin composite class I restorations: a 54-month randomized clinical trial.

The objective of this longitudinal clinical randomized trial was to evaluate the clinical performance of a nanofilled and a nanohybrid resin composite in Class I occlusal restorations of posterior teeth over the course of 54 months. Forty-one adolescents participated in the study. The teeth were restored with Adper Single Bond 2 (3M ESPE) and nanofilled (Filtek Z350, 3M ESPE), nanohybrid (Esthet-X, Dentsply) and microhybrid Filtek Z250 (3M ESPE) used as a control. After 54 months, the restorations were evaluated in accordance with the modified United States Public Health Service criteria. The McNemar and Friedman tests were used for statistical analysis, at a level of significance of 5%. Five failed restorations were observed during the follow-up. A change to unacceptable restoration occurred for one Esthet-X, two Filtek Z350, and two Filtek Z250 restorations, which received the clinically unacceptable score, Charlie, for both anatomic form and marginal adaptation. Secondary caries and postoperative sensitivity occurred in one Filtek Z250 and one Filtek Z350 restoration. When the five evaluation periods (baseline and six, 12, 30, and 54 months) were compared, significant differences were found in the marginal adaptation of Filtek Z250 and Filtek Z350. Significant differences in the roughness criteria (p=0.005) were also observed when the three composites were compared after 54 months (Filtek Z350 > Filtek Z250 > Esthet-X), always within clinically acceptable limits. The materials investigated showed acceptable clinical performance for Class I restoration after 54 months. Long-term reevaluations are necessary for a more detailed analysis of these composites.

Dual-cured etch-and-rinse adhesive systems increase the bond durability of direct coronal dentin restorations.

This study aimed to evaluate the bond durability of dentin restorations bonded with light- or dual-cured etch-and-rinse adhesive systems. A three-step adhesive system (Scotchbond Multipurpose Plus), an acetone-based two-step adhesive system (Prime & Bond 2.1), and an ethanol-based two-step adhesive system (Excite) were tested. Both the light- and the dual-cured versions were evaluated. High C-factor dentin cavities were prepared on 120 bovine incisors, which were then restored with resin composite (n=10). The samples were stored in water for 24 hours, and half of them were subjected to additional degradation with 10% NaOCl for five hours. The push-out bond strength test was performed in a universal testing machine until failure. Failure modes were evaluated by scanning electron microscopy. Data were analyzed by three-way analysis of variance and Tukey tests (p<0.05). The dual-cured adhesive system presented a higher immediate bond strength and durability than those that were light cured. The three-step adhesive system produced the highest values, whereas the acetone-based adhesive system produced the lowest result. Therefore, the use of dual-cured etch-and-rinse adhesive systems can induce increased bond durability to direct coronal dentin restorations.

Efficacy of a novel at-home bleaching technique with carbamide peroxides modified by CPP-ACP and its effect on the microhardness of bleached enamel.

This study was designed to evaluate in vitro the efficacy of a novel at-home bleaching technique using 10% or 16% carbamide peroxide modified by casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) and its influence on the microhardness of bleached enamel. A total of 40 bovine incisors were divided into four groups (n=10) according to the bleaching agent used: 10% carbamide peroxide only; a blend of 10% carbamide peroxide and a CPP-ACP paste; 16% carbamide peroxide only; and a blend of 16% carbamide peroxide and a CPP-ACP paste. During the 14-day bleaching regimen, the samples were stored in artificial saliva. The Vickers microhardness and color of the teeth were assessed at baseline (T0) and immediately after the bleaching regimen (T14) using a microhardness tester and a spectrophotometer, respectively. The degree of color change was determined by the Commission Internationale de l'Eclariage (CIE) L*a*b* system (ΔE, ΔL*, Δa*, and Δb*) and Vita shade guide parameters. The data were analyzed by analysis of variance and the Tukey test (p<0.05). The teeth that were bleached with a blend of peroxide (10% or 16%) and the CPP-ACP paste presented increased microhardness values at T14 compared with T0, whereas the samples that were bleached with peroxide only did not show any differences in their microhardness values. All of the bleaching agents were effective at whitening the teeth and did not show a statistically significant difference using the CIEL*a*b* system (ΔE, ΔL*, Δa*, and Δb*) or the Vita shade guide parameters. The use of a CPP-ACP paste with carbamide peroxide bleaching agents increased the bleached enamel's microhardness and did not have an influence on whitening efficacy.

Expresión de marcadores embrionarios en células mesenquimales de pterygium / Expression of embryonic markers in pterygium derived mesenchymal cells

Propósto: La destrucción de la barrera del epitelio limbal es el mecanismo más importante en la formación del pterygium. Se piensa que proviene de la activación y proliferación de células madre (stem cells) del epitelio limbal. El objetivo de este estudio ha sido determinar la presencia de células mesenquimíticas indiferenciadas (stem cells) en cultivos celulares obtenidos de pterygium humano. Métodos: Las células de 6 pterygium humanos fueron aisladas mediante explantos y cultivadas en amniomax. Al alcanzar la confluencia, las células fueron sembradas en microplacas de 24 pocillos. Los cultivos celulares fueron estudiados en el 2.¡- subcultivo. Se analizá mediante inmunofluorescencia la expresión de los marcadores de células madre embrionarias, OCT3/4 y CD9. Los diferentes fenotipos celulares fueron caracterizados con los anticuerpos monoclonales anti-CD31, Á-actina y vimentina. Resultados: Toda la población celular obtenida de pterygium muestra expresión para vimentina. Menos de un 1% de las células presentaron expresión para los marcadores CD31 y Á-actina. La mayor parte de la población celular fue positiva para los marcadores embrionarios OCT3/4 y CD9. Conclusión: La población celular expandida a partir de pterygium está compuesta por células de fenotipo mesenquimal, que muestran expresión de marcadores embrionarios OCT3/4 y CD9. Esta población, con un alto grado de indiferenciación, podrá ser responsable de la alta tasa de recurrencia del pterygium tras su extirpación quirurgica (AU)

BackgroundDestruction of the limbal epithelium barrier is the most important mechanism of pterygium formation (conjunctiva proliferation, encroaching onto the cornea). It is thought to arise from activated and proliferating limbal epithelial stem cells. The objective of this study is to evaluate the presence of undifferentiated mesenchymal cells (stem cells) in cultured cells extracted from human pterygium.Material and methodsCells from 6 human pterygium were isolated by explantation and placed in cultures with amniomax medium. Once the monolayer was reached the cells were seeded onto 24 well microplates. The cells were studied in the second sub-culture. The immunohistochemical expression of different embryonic stem cell markers, OCT3/4 and CD9, was analysed. The differentiated phenotypes were characterised with the monoclonal antibodies anti-CD31, ¦Á-actin and vimentin.ResultsAll the cell populations obtained from pterygium showed vimentin expression. Less than 1% of the cells were positive for CD31 and ¦Á-actin markers. The majority of the cell population was positive for OCT3/4 and CD9.ConclusionsThe cell population obtained from pterygium expressed mesenchymal cell phenotype and embryonic markers, such us OCT3/4 and CD9. This undifferentiated population could be involved in the large recurrence rate of this type of tissue after surgery(AU)

[Expression of embryonic markers in pterygium derived mesenchymal cells]. / Expresión de marcadores embrionarios en células mesenquimales de pterygium.

BACKGROUND: Destruction of the limbal epithelium barrier is the most important mechanism of pterygium formation (conjunctiva proliferation, encroaching onto the cornea). It is thought to arise from activated and proliferating limbal epithelial stem cells. The objective of this study is to evaluate the presence of undifferentiated mesenchymal cells (stem cells) in cultured cells extracted from human pterygium. MATERIAL AND METHODS: Cells from 6 human pterygium were isolated by explantation and placed in cultures with amniomax medium. Once the monolayer was reached the cells were seeded onto 24 well microplates. The cells were studied in the second sub-culture. The immunohistochemical expression of different embryonic stem cell markers, OCT3/4 and CD9, was analysed. The differentiated phenotypes were characterised with the monoclonal antibodies anti-CD31, α-actin and vimentin. RESULTS: All the cell populations obtained from pterygium showed vimentin expression. Less than 1% of the cells were positive for CD31 and α-actin markers. The majority of the cell population was positive for OCT3/4 and CD9. CONCLUSIONS: The cell population obtained from pterygium expressed mesenchymal cell phenotype and embryonic markers, such us OCT3/4 and CD9. This undifferentiated population could be involved in the large recurrence rate of this type of tissue after surgery.

DNA sequence analysis and the phylogeographical history of the rodent Deltamys kempi (Sigmodontinae, Cricetidae) on the Atlantic Coastal Plain of south of Brazil.

The rodent Deltamys kempiThomas, 1917 is found on the Coastal Plain - a recently formed geographic region located on Brazil's south-east coast. Considering that Deltamys is the only South American sigmodontine with a sex chromosome system of type X(1)X(1)X(2)X(2)/X(1)X(2)Y, this investigation was focused on the phylogeographic history of this taxon by using gene sequence analysis, trying to clarify when Deltamys differentiated, what was its centre of diversification, and what were the probable routes it used to reach its present distribution. We analysed sequences of the mitochondrial cytochrome b gene and nuclear recombination activating gene 2, performed cranial measurements and searched for centric fusions in individuals collected in distinct localities. The results, clearly demonstrate that D. kempi, on the Coastal Plain, divided into two groups, one occupying a small portion to the north of this region and the other spreading widely to the south. In this process, the phenomena of marine transgression and regressions which moulded its habitat, together with the occurrence of successive chromosomal rearrangements, were certainly the fundamental factors in shaping D. kempi diversification.

[Persistent corneal defects treated with botulinum toxin-induced ptosis]. / Ptosis inducida por toxina botulínica como tratamiento de los defectos corneales persistentes.

OBJECTIVES: To evaluate the use of botulinum toxin (BTX) induced ptosis in the treatment of corneal pathology. METHODS: We employed two BTX injections into the superior lid of 10 eyes (9 patients). We evaluated the degree of ptosis, its duration and the effect on the corneal lesion. RESULTS: Complete ptosis resulted in seven eyes and the corneal pathology resolved in all of them. There were no relevant complications. CONCLUSIONS: BTX treatment is a simple and safe technique for treating refractory corneal pathology. It has significant advantages over surgical tarsorrhaphy and is especially useful where the pathology does not require surgery.

[Brown-McLean syndrome after insertion of an anterior chamber intraocular lens: description of one case]. / Síndrome de Brown-McLean con lente intraocular de cámara anterior: descripción de un caso.

CASE REPORT: We report one case of Brown-McLean syndrome. DISCUSSION: In this case, a 71-year-old male developed a Brown-McLean syndrome after implantation of an anterior chamber lens in one aphakic eye. A phacoemulsification procedure was performed in the other eye without development of corneal clearance alterations in the next 7 years. The cause of Brown-McLean syndrome is still unexplained. It is possible that it could develop in eyes with a genetic predisposition when these eyes are exposed to certain conditions, such as insertion of an anterior chamber lens.

Comparación de las guías de práctica clínica de riesgo vascular / Comparison of vascular risk clinical practice guides

OBJETIVO. En estos últimos años diversos autores y organizaciones han desarrollado guías de práctica clínica (GPC) con recomendaciones para el manejo del paciente con riesgo vascular. El objetivo es la descripción de la variabilidad existente entre las recomendaciones de las distintas GPC. MÉTODOS. Se comparan los autores de las distintas GPC y si están basadas en la evidencia y en el riesgo vascular (los factores de riesgo, el método de estimación y su estratificación), tanto en aquellas guías de carácter internacional, que son la referencia bibliográfica de las guías españolas, como en las GPC nacionales en Atención Primaria. RESULTADOS. Las GPC están basadas en la evidencia o en la adaptación de otras GPC ya existentes. La importancia de las últimas versiones de las GPC radica en la llamada de atención sobre los nuevos marcadores potenciales de las enfermedades cardiovasculares (ECV): la homocisteína, los marcadores de inflamación, los factores trombogénicos, los factores genéticos, la microalbuminuria y la aterosclerosis subclínica. También prestan mayor atención al síndrome metabólico. CONCLUSIONES. Existe variabilidad entre las GPC revisadas tanto en los autores como en los factores de riesgo contemplados y en el método de estimar y de estratificar el riesgo. Los nuevos marcadores de ECV todavía no se consideran aplicables en la estimación de riesgo cardiovascular rutinario de la ECV. Se espera que la combinación de los factores de riesgo tradicionales y de los factores de riesgo que emergen facilite la valoración del riesgo global de los pacientes con el fin de optimizar los esfuerzos diagnósticos y terapéuticos. Sugerimos que en la práctica clínica los médicos de Atención Primaria utilicen la GPC editada por la semFYC II

OBJECTIVES: In recent years, several authors and organizations have developed clinical practice guides (CPG) with recommendations for the management of patients with vascular risk. Description of existing variability between recommendations of the different CPG. METHODS. A comparison is made of authors of the different CPG and if they are based on evidence and vascular risk (risk factors, estimation method and its stratification) both in those international guides, that are the bibliographic reference of the Spanish guidelines, as well as in the national CPG in Primary Care. RESULTS. The CPG are based on evidence or the adaptation of other already existing CPG. The importance of the last versions of the CPG is found in the call to attention on the new potential markers of cardiovascular diseases: homocysteine, inflammation markers, thrombogenic factors, genetic factors, microalbuminuria and subclinical atherosclerosis. Greater attention is also given to the metabolic syndrome. CONCLUSIONS. There is variability between the CPG reviewed both in the authors and in the risk factors contemplated and in the method of estimating and stratifying risk. The new CVD markers are still not considered applicable in the estimation of routine cardiovascular risk of CVD. It is hoped that the combination of the traditional risk factors and the risk factors that emerge will facilitate the assessment of global risk of the patients in order to optimize diagnostic and therapeutic efforts. We suggest that Primary Care physicians use the CPG edited by the semFYC (Spanish Society of Family and Community Medicine) II in the clinical practice

A morphological and tensile bond strength evaluation of an unfilled adhesive with low-viscosity composites and a filled adhesive in one and two coats.

OBJECTIVE: The purpose of this study was to measure the tensile bond strength (TBS) testing of resin composite to dentin of three low-viscosity composites, in association with an unfilled adhesive, and a filled adhesive one and two coats respectively, and to evaluate and compare the SEM morphological observations. METHODS: The labial surface of 120 bovine lower incisors were ground to obtain a flat dentin surface allowing demarcation of a 4 mm diameter area with adhesive tape. The teeth were randomly divided in six groups of 20 each. The dentin of each ground surface was etched with 35% H(3)PO(4) for 15s, followed by application of the respective adhesive: Single Bond (SB) for Groups 1, 2, 3 and 6; Optibond Solo (OS) for Groups 4 and 5. In Groups 1 and 4, a resin composite rod with a wire loop was luted directly to the adhesive surface with Z100. Group 2 received an intermediate layer of Flow It (FI) composite; Group 3 received an intermediate layer of Protect Liner F (PLF) composite; Group 5 received a second coat of OS; and Group 6 received an intermediate layer of an experimental low-viscosity composite (EM). A resin composite rod was luted to the surface of each specimen with Z100 resin composite. All specimens were stored in distilled water at 37 degrees C for 24h prior to TBS testing. Each specimen was inspected by SEM and classified according to adhesive or cohesive failure mode. One specimen of each group was cut longitudinally, polished and prepared for SEM observation. RESULTS: The TBS values were: Group 1 (7.86MPa+/-2.28), Group 2 (7.62MPa+/-1.85), Group 3 (7.60MPa+/-2.14), Group 4 (7.96MPa+/-2.36), Group 5 (7.50MPa+/-2.70) and Group 6 (7.18MPa+/-2.40). No significant statistical differences were observed among the groups. However, the analyses of the failure mode presented a considerable variation. SIGNIFICANCE: The use of a filled adhesive or an unfilled adhesive along with a low-viscosity composite as an intermediate layer may provide a stress absorbing layer, whereby improving the preservation of the bonded interface area.

Cytologic characteristics of abnormal cells in prior "normal" cervical/vaginal Papanicolaou smears from women with a high grade squamous intraepithelial lesion.

BACKGROUND: Some cervical/vaginal Papanicolaou (Pap) smears previously diagnosed as normal in women with a high grade squamous intraepithelial lesion (HSIL) are found to contain abnormal cells on retrospective review. This study characterized and quantitated such cells in 100 Pap smears. METHODS: One hundred prior negative Pap smears from 49 women with a newly diagnosed HSIL were rescreened, as were 107 negative Pap smears from 100 women with normal subsequent smears. Cases were assorted randomly so that the rescreener was unaware of the subsequent follow-up. RESULTS: All 12 Pap smears found to contain atypical mature and immature metaplastic cells belonged to the group with a subsequent HSIL (P = 0.001). In addition, 18 of the 100 previously negative Pap smears (18%) had immature metaplastic cells without nuclear atypia compared with 4 of 107 Pap smears (4%) in the control group (P = 0.0007). CONCLUSIONS: This study supports the observations of other authors that atypical metaplastic cells, especially those of the immature type, are associated with HSIL. These cells most likely are HSIL lesional cells, which are not easily recognizable as such. Immature metaplastic cells without atypia also were shown to be associated significantly with HSIL in this study. These cells may be unrecognizable lesional cells or a marker of increased risk for HSIL and deserve further study.