Acidogenic and aciduric properties of Streptococcus mutans serotype c according to its genomic variability.

Streptococcus mutans (S. mutans) has a wide genetic diversity that contributes to its phenotypic heterogeneity, and may be related to attributes associated with acidogenicity and aciduricity. The aim of this study was to evaluate the acidogenic and aciduric properties of S. mutans serotype c isolates from saliva of schoolchildren according to the genomic variability. S. mutans isolates were identified by polymerase chain reaction. Fifty S. mutans serotype c isolates were genotyped by pulsed field gel electrophoresis and tested for their ability to produce and resist acid. Three specific genotypes were identified in the caries-active group and only one in the caries-free group. Although isolates were similarly acidogenic, an exclusive caries-active genotype had the greatest glycolytic activity. In contrast, isolates exhibited variable aciduricity, and three caries-active genotypes were the least aciduric. We concluded that there is genetic variability within serotype c. Acid production was similar regardless of the caries status but correlated with the number of genotypes. In addition, resistance to acid could be an important characteristic for the establishment and colonisation of specific genotypes in children with caries. However, it is important to evaluate children's intrinsic characteristics and other phenotypic properties to explain the physiopathological behaviour of the different genotypes.

F-Spondin Is the Signal by Which 2-Methoxyestradiol Induces Apoptosis in the Endometrial Cancer Cell Line Ishikawa.

The metabolite 2-methoxyestradiol (2ME) is an endogenous estrogen metabolite with potential therapeutic properties in reproductive cancers. However, the molecular mechanisms by which 2ME exerts its anticancer activity are not well elucidated. The purpose of this study was to determine the molecular signals associated with the apoptotic effects of 2ME in a human endometrial cancer cell line. Ishikawa cells were treated with non-apoptotic (0.1 µM) or apoptotic concentrations (5 µM) of 2ME, and 12 hours later mRNA levels for Scd2, Snx6, and Spon1 were determined by real-time PCR. We then investigated by immunofluorescence and Western blot the expression and distribution of F-spondin, encoded by Spon1, in Ishikawa cells treated with 2ME 5 µM at 6, 12, or 24 h after treatment. The role of estrogen receptors (ER) in the effect of 2ME on the Spon1 level was also investigated. Finally, we examined whether 2ME 5 µM induces cell death in Ishikawa cells pre-incubated with a neutralizing F-spondin antibody. Non-apoptotic or apoptotic concentrations of 2ME decreased Scd2 and increased Snx6. However, Spon1 was only increased with the 2ME apoptotic concentration. F-spondin protein was also increased at 12 and 24 h after 2ME treatment, while 2ME-induced Spon1 increase was independent of ER. Neutralization of F-spondin blocked the effect of 2ME on the cell viability. These results show that F-spondin signaling is one of the components in the apoptotic effects of 2ME on Ishikawa cells and provide experimental evidence underlying the mechanism of action of this estrogen metabolite on cancer cells.

Genomic and phenotypic diversity of Streptococcus mutans.

BACKGROUND: Streptococcus mutans (S. mutans) is a commensal microorganism found in the human oral cavity. However, due to environmental changes, selective pressures, and the presence of a variable genome, it adapts and may acquire new physiological and metabolic properties that alter dental biofilm homeostasis, promoting the development of dental caries. Although the plasticity and heterogeneity of S. mutans is widely recognized, very little is known about the mechanisms for the expression of pathogenic properties in specific genotypes. HIGHLIGHT: The implementation of molecular biology techniques in the study of S. mutans has provided information on the genomic diversity of this species. This variability is generated by genome rearrangements, natural genetic transformation, and horizontal gene transfer, and continues to grow due to an open pan-genome. The main virulence factors associated with the cariogenic potential of S. mutans include adhesion, acid production (acidogenicity), and acid tolerance (aciduricity), and also show variability. These factors coordinate the modification of the physicochemical properties of the biofilm, which results in the accumulation of S. mutans and other acidogenic and aciduric species in the oral cavity. CONCLUSION: We review the current literature on the main processes that generate S. mutans genomic diversity, as well as the phenotypic variability of its main virulence factors. S. mutans achieves its pathogenesis by sensing the intra- and extracellular environments and regulating gene transcription according to perceived environmental modifications. Consequently, this regulation gives rise to differential synthesis of proteins, allowing this species to potentially express virulence factors.

Genetic diversity of Streptococcus mutans serotype c isolated from white spot and cavitated caries lesions from schoolchildren.

OBJECTIVE: To determine the genetic diversity of Streptococcus mutans (S. mutans) serotype c isolated from white spot and cavitated caries lesions of schoolchildren. METHODS: S. mutans isolates were obtained and identify by Polymerase Chain Reaction (PCR) from 28 schoolchildren. A total of 92 S. mutans isolates, identified as serotype c by PCR, were analyzed by pulsed field gel electrophoresis after digestion of genomic DNA with SmaI enzyme. 62 isolates were obtained from white spot and cavitated caries lesions of schoolchildren that presented both lesions simultaneously and 30 isolates were from saliva and biofilm samples of schoolchildren without dental caries. Cluster analyses were performed using the Dice coefficient of the BioNumerics software version 6.0. RESULTS: It was possible to determine the serotype in 190 isolates out of 255 isolates identified as S. mutans. Serotype c was the most frequent (n = 139), followed by serotype f (n = 31) and serotype e (n = 20). After analyzing the dendograms of the 92 serotype c isolates, this study identified three strains present in both types of lesions, two strains specific to the type of lesion: one strain from the white spot lesion and one strain from the cavitated caries lesion, and five strains specific to children with caries versus four strains for children without caries. CONCLUSION: S. mutans serotype c genetic variability is similar in terms of the number of strains present according to the caries status and type of lesion.

Changes in the gene expression pattern induced by 2-methoxyestradiol in the mouse uterus.

2-Methoxyestradiol (2ME) is an estrogen metabolite with antitumor and antiangiogenic properties, although their effects on the reproductive tissues are not well-determined. Furthermore, it is not very clear whether 2ME is part of the intracellular signaling of estradiol (E2) or it acts through other signaling pathways. The purpose of this study was to determine changes in the gene expression pattern in the mouse female reproductive tract induced by 2ME, under conditions in which this metabolite has no estrogenic activity. Therefore, we first compared the effect of 2ME or E2 on the uterine weight and epithelial cell height, and on the ovarian weight and the number of follicles of immature mice. Then, we examined the gene expression profile in the uterus of immature mice treated with 2ME or E2 and we selected three genes scd2, snx6, and spon1, to confirm differential regulation by E2 and 2ME in the uterine cells using real-time PCR. Finally, in order to explore the physiologic relevance of the 2ME-induced genes we determined the expression and localization of the F-spondin protein encoded by spon1 in the uterus of mature mice treated with E2 or 2ME. Estradiol and 2ME reduced the ovarian weight and decreased the number of follicles ≥ 300 µm, whereas E2 increased the uterine weight and epithelial cell height but not 2ME, indicating that 2ME did not have estrogenic activity in the mouse uterus. Microarray analysis showed that 1.8 % of the uterine genes were regulated by E2 and 0.23 % by 2ME, while 0.04 % was regulated by E2 and 2ME. The mRNA for scd2 was exclusively increased by 2ME, whereas snx6 and spon1 were up-regulated by E2 and 2ME, but the response to 2ME was more intense. F-spondin was mainly expressed in the uterine stroma layer although 2ME or E2 did not change its localization in the uterine cells. We conclude that 2ME regulates a group of genes in the mice uterus, independently of estrogenic activity, suggesting a functional involvement of 2ME in the mammalian uterus.

Medidas radiográficas y corporales para diagnosticar relaciones de clase II utilizando análisis estadístico multivariado / Radiographic and body measurements to diagnose class II relationships using a multivariate statistical analysis

Para el diagnóstico en ortodoncia se han utilizado más de 40 variables dependiendo de los autores. De ellas, algunas aportan información para realizar el diagnóstico de las relaciones de clase II. Cuando se tienen tantas variables es necesario utilizar un método que permita identificar las más representativas y eliminar las redundantes. Para el logro de este objetivo se utilizó el análisis estadístico multivariado (análisis de componentes principales, análisis de factor, análisis de agrupamiento y análisis discriminante), con el cual se identificaron las variables: ángulo de Lande, ánguilo de la convexidad y la distancia del punto A a la perpendicular de FH; igualmente, se identificaron los subgrupos y los factores (constructor) por género; por último, se obtuvo la función discriminante para identificar las relaciones clase II. Con el análisis multivariado se logró reducir el número de variables utilizadas para el diagnóstico.

Medidas corporales y craneofaciales para definir criterios de variación fenotípica en el síndrome de Down, Medellín 1998 / Body and craneofacial measurements for defining criteria of phenotypic variation in Down's syndrome

Con el propósito de establecer las medidas directas que permitan discriminar a los pacientes con síndrome de Down (SD) de los no SD, caracterizar los de SD, hallar las diferencias con los no SD, determinar subgrupos dentro de los de SD y comparar las observaciones realizadas por los clínicos, se estudiaron 24 pacientes con SD, de sexo masculino y 5 años de edad, que presentaban trisomía libre del cromosoma 21 y que no tenían anomalías cardíacas congénitas, y 24 niños sanos de la misma edad como controles. Se realizaron 37 medidas directas en cabeza, cara, tronco, miembros superiores e inferiores. Tres de las 37 clasifican y separan a los de SD de los no SD (100 por ciento); cinco observaciones realizadas por los clínicos sólo discriminaron el 79,1 por ciento de los de SD. En la agrupación por variables se conformaron cinco subgrupos en los de SD; sólo uno de ellos contenía las variables utilizadas por los clínicos. Las variables con mayor coeficiente de variación fueron: peso, longitud de la pierna, longitud de la mano, ancho de la oreja, ancho del hélix e índice nasal en el SD; peso, ancho del hélix e índice nasal en los no SD. Los niños con SD presentaron menores talla y peso

Twenty four five year old male children with full 21 trisomy syndrome, without congenital heart anomalies, and twenty four healtly children of the same age and sex, as controls, were studied, in order to define the direct measurements that permit discriminating between Down's syndrome (DS) and no Down syndrome (NDS), to characterize those with DS, to find the differences with the NDS ones, to determine DS subgroups and to compare the observations of the clinicians. Thirty seven direct measurements of head, face, trunk, upper and lower limbs were performed. Out of them three classified and separated DS and NDS children (100%). Five observations performed by clinicians only discriminate 79,1% of the DS children. In the DS children, by grouping the variables, five subgroups were detected; only one of these included the variables used by the clinicians, namely: weight, leg length, hand length, ear width, helix width and nasal index in DS and weigth, helix width and nasal index in NDS had the higher variation coefficient. DS children have lesser weight and size.