Factores de virulencia de Staphylococcus aureus asociados con infecciones mamarias en bovinos: relevancia y rol como agentes inmunógenos / [Virulence factors of Staphylococcus aureus associated with intramammary infections in cows: relevance and role as immunogens].

Staphylococcus aureus is the most prevalent mastitis pathogen in Argentina and worldwide. Lack of effectiveness of traditional control measures based on milking hygiene and antibiotic therapy against this organism has led to the development of alternatives directed to prevent the disease. Among them, the manipulation of host immune mechanisms through vaccination has been explored. The identification of virulence factors able to stimulate host immune defenses is key to developing a rational vaccine. S. aureus has multiple virulence factors that interact with the host at different stages of an intramammary infection. The use of some of these factors as immunogens has been shown to elicit protective responses in the host. The structure, function, and use as immunogens of S. aureus virulence factors considered to be relevant at different stages of intrammamary infections caused by this organism are reviewed in this article.

Fibronectina fetal como predictor del trabajo de parto en mujeres mexicanas / Fetal fibronectin as a predictor of labor in Mexican women

Introducción: la presencia de fibronectina fetal en secreciones vaginales ha sido considerada como un predictor de trabajo de parto en embarazo de término y de pretérmino. Objetivo: evaluar la validez predictiva de la fibronectina en embarazadas que acudieron al Hospital General SSH de Pachuca, México. Metodología: se incluyeron pacientes embarazadas que acudieron al hospital para control de su embarazo. Se determinó la fibronectina fetal en todas las participantes y se dio un seguimiento hasta el inicio del trabajo de parto. Resultados: participaron un total de 148 pacientes, siendo un grupo con 53 pacientes con menos de 37 semanas de gestación (SG) y otro grupo con 95 pacientes con 37 ó más SG. En general, la prueba mostró una sensibilidad promedio de 72,5 por ciento y una especificidad promedio de 82,9 por ciento para ambos grupos. Conclusión: sobre la base de los resultados obtenidos, recomendamos utilizar la prueba de fibronectina en embarazadas a partir de las 32 semanas de gestación, tanto en los servicios de urgencias como de consulta externa.

Background: The presence of fetal fibronectin in vaginal secretions has been regarded as a predictor of labor in pregnant term and preterm. Objective: For this reason the purpose of this study was to evaluate the predictive validity of fibronectin in pregnant women who attended the General Hospital SSH Pachuca, Hidalgo, Mexico. Methodology: We included pregnant patients admitted to hospital for pregnancy control. Fetal fibronectin was determined in all participants and then followed until the onset of labor. Results: A total of 148 patients participated. One group with 53 patients less than 37 weeks gestation, and another group of 95 patients with 37 or more weeks gestation. In general, the test showed an average sensitivity of 72.5 percent and specificity 82.9 percent average for both groups. Conclusion: Based on these results, we recommend using fibronectin test in pregnant women after 32 weeks of gestation, both in emergency departments and outpatient clinics.

Gangliosides enhance migration of mouse B16-melanoma cells through artificial basement membrane alone or in presence of laminin or fibronectin.

The migration of B16LuF1 cells, B16-melanoma cells of lower metastatic potential to lung was enhanced through artificial basement membrane in presence of gangliosides of B16LuF1 cells as well as gangliosides of B16-melanoma cells of higher metastatic potential to lung, namely, B16LuF5 and B16LuF10 cells. The same concentration (50 microM) of gangliosides of B16LuF1, B16LuF5 and B16LuF10 cells gradually increased the migration of B16LuF1 cells through basement membrane. Moreover, B16LuF10 cell gangliosides modified the migratory effect of laminin and fibronectin on B16LuF1 cells. Laminin alone increased migration of B16LuF1 cells whereas fibronectin alone decreased migration of the same cells. When B16LuF10 cell gangliosides were used in combination with fibronectin, gangliosides removed the migration inhibitory effect of fibronectin resulting in net enhancing effect. Gangliosides in association with laminin also increased the enhancing effect of laminin on migration of B16LuF1 cells. Thus, gangliosides showed additive enhancing effect when used in combination with laminin. However, effect of individual gangliosides were different. Out of six gangliosides isolated from B16LuF10 cells only two gangliosides corresponding to standard gangliosides GM2 and GM3 enhanced migration of B16LuF1 cells. The migration of B16LuF1 cells in presence of each of the remaining four gangliosides corresponding to GT1b, GD1b, GD1a and GM1 was not altered and was comparable to that of untreated control. Thus, gangliosides of B16 melanoma cells alone or in combination with laminin or fibronectin enhanced migration of B16 melanoma cells through artificial basement membrane, suggesting possible role of tumor gangliosides during invasion of metastatic tumor cells through basement membrane of the surrounding tissues in vivo.

Promotion of fibronectin independent invasion by C5a peptidase into epithelial cells in group A Streptococcus.

BACKGROUND & OBJECTIVES: Group A Streptococcus, causative agent of several clinical manifestations codes for multiple protein invasins which help the bacterium to enter non-phagocytic cells. C5a peptidase (SCPA) is a surface protein conserved among different serotypes of M1 strain. The present study was taken up to study SCPA promoted fibronectin independent entry of GAS into epithelial cells. METHODS: An isogenic 90226 emm1deltaAB (M1(-)) mutant was constructed with thermosensitive pGhost vector. This isogenic M1(-) mutant expressed SCPA on the surface as determined by Western blotting and immunofluorescence. RESULTS: On preincubation with anti-SCPA serum, the isogenic M1(-) strain exhibited 54 per cent decreased invasion as compared to the bacteria incubated with control serum. Also, purified recombinant SCPA proteins blocked internalization of M1(-) streptococci into HEp-2 cells. The M1(-) strain invaded at the same efficiency in the presence or absence of fibronectin. INTERPRETATION & CONCLUSION: These results suggested that SCPA acted as a potential invasin of group A streptococcus and promoted invasion independent of fibronectin.

Heparan sulfate and control of cell division: adhesion and proliferation of mutant CHO-745 cells lacking xylosyl transferase

We have examined the role of cell surface glycosaminoglycans in cell division: adhesion and proliferation of Chinese hamster ovary (CHO) cells. We used both wild-type (CHO-K1) cells and a mutant (CHO-745) which is deficient in the synthesis of proteoglycans due to lack of activity of xylosyl transferase. Using different amounts of wild-type and mutant cells, little adhesion was observed in the presence of laminin and type I collagen. However, when fibronectin or vitronectin was used as substrate, there was an enhancement in the adhesion of wild-type and mutant cells. Only CHO-K1 cells showed a time-dependent adhesion on type IV collagen. These results suggest that the two cell lines present different adhesive profiles. Several lines of experimental evidence suggest that heparan sulfate proteoglycans play a role in cell adhesion as positive modulators of cell proliferation and as key participants in the process of cell division. Proliferation and cell cycle assays clearly demonstrate that a decrease in the amount of glycosaminoglycans does not inhibit the proliferation of mutant CHO-745 cells when compared to the wild type CHO-K1, in agreement with the findings that both CHO-K1 and CHO-745 cells take 8 h to enter the S phase

The alternative splicing & expression of fibronectin IIIcs segment and its relationship with wound healing / 法医学杂志

Fibronectin is an important large adhesive glycoprotein of the extracellular matrix, which is alternatively spliced in three regions, designated EIIIA, EIIIB and IIIcs respectively. IIIcs contains two binding domains for a variety of cell surface and extracellular ligands. Through this multiplicity of adhesive activities, IIIcs can fulfill key roles in a broad spectrum of physiological processes, such as cell spreading and migration, differentiation and embryogenesis, wound healing, malignant transformation and metastasis, etc. Here, we will discuss the structure, biological property, and function of IIIcs splicing variants and its forensic applications.

Extracellular matrix molecules play diverse roles in the growth and guidance of central nervous system axons

Axon growth and guidance represent complex biological processes in which probably intervene diverse sets of molecular cues that allow for the appropriate wiring of the central nervous system (CNS). The extracellular matrix (ECM) represents a major contributor of molecular signals either diffusible or membrane-bound that may regulate different stages of neural development. Some of the brain ECM molecules form tridimensional structures (tunnels and boundaries) that appear during time- and space-regulated events, possibly playing relevant roles in the control of axon elongation and pathfinding. This short review focuses mainly on the recognized roles played by proteoglycans, laminin, fibronectin and tenascin in axonal development during ontogenesis

Moléculas de adhesión y su importancia en odontología: revisión de la literatura / Adhesion molecules and its importance in dentistry

En la actualidad se reconoce que las interacciones que se suceden entre las células entre sí y de éstas con los componentes de la matriz extracelular se producen por la intervención de las Moléculas de Adhesión. Las Moléculas de adhesión son glucoproteínas distribuidas en gran cantidad de células que le permiten al organismo realizar funciones tanto fisiológicas, como la adhesión entre las células epiteliales, como fisiopatológicas, por ejemplo la inflamación. Es por ello que se hace imperativo conocer estas familias, para así entender los procesos que se desarrollan en las diversas actividades, normales o patológicas, de la cavidad bucal

Matriz extra-celular: fibronectina / Extracellular matrix: fibronectine

A fibronectina é uma glicoproteína presente no plasma sangüíneo e nos tecidos. Tem propriedade de ligar-se a si mesma e a várias outras substâncias diferentes, tais como a fibrina, a heparina, bactérias, colágeno, fibroblastos, e outras células. Por esta propriedade ligante, desempenha funções fisiológicas múltiplas e tem participação importante em diversos processos patológicos, tanto em sua forma intacta como pela presença de seus isômeros e fragmentos. Fisiologicamente, a fibronectina é responsável pela orientação da migração celular na embriogênese e participa na homeostase e a coagulação sangüínea e na condrogênese. A fibronectina está envolvida em processos osteoartríticos, na produção de anomalias nos membros e em condições patológicas que afetam a mucosa oral humana

Funcion de distintas formas de fibronectina en el desarrollo de foliculos bovinos in vitro / Role of different forms of fibronectin in in vitro bovine follicular development

En el presente estudio, se analizó la posibilidad de que las distintas formas de fibronectina (FN), producidas como resultado de la maduración alternativa (alternative splicing) del mensajero, ejerzan funciones diferenciales en el desarrollo folicular. En particular se determinó la presencia de la región ED-I, ausente en la FN plasmática, tanto a nivel de mensajero como de proteína, durante este proceso. El análisis de los niveles de FN en fluidos foliculares correspondientes a distintas etapas de desarrollo mostró marcadas variaciones en la concentración de FN ED-I+ y los de permanecieron relativamente constantes. En folículos corespondientes a la fase de selección se observó una correlación inversa entre los niveles de FN ED-I+ y los de estradio (p<0.001). El tratamiento con estradiol no tuvo efecto sobre el splicing alternativo de FN en cultivos de células de la granulosa bovinas, mientras que el AMPc tuvo un efecto inhibitorio sobre la incorporación de ED-I. Por otra parte, el factor de crecimiento transformante tipo beta (TGF-beta) estimuló tanto la produción de FN total como la inclusión de la región ED-I. Este efecto fue verificado tanto a nivel de la proteína (Western blots) como del ARN mensajero (Northern blots). Un péptido correspondiente a la región ED-I tuvo un efecto estimulatorio sobre el crecimento de una línea de células de la granulosa bovinas (BGC-1) mientras que el péptido correspondiente e las regiones flanqueantes no tuvo efecto. Los datos presentados en este estudio plantean una nueva forma de regulación mediante la cual cambios cualitativos en la estructura primaria de la FN podrían mediar algunas de las acciones de gonadotrofinas y factores intraováricos durante el desarrollo folicular.

Thrombospondin: relationship to protease and growth factor/cytokine activity

1. The finding in the last two years of different proteins presenting structural homology with platelet thrombospondin (TSP-1) has permitted to establish the existence of a set of related genes referred to as thrombospondin family. While much work remains to be done concerning the characterization of the newly described members of the family, careful studies carried out on TSP-1 have been implicating this high molecular weight molecule (420-450 KDa) in a variety of aspects of celular physiology. 2. The present text discusses the implications of the matrix-bound and fluid TSP-1 forms for cell adhesion and protease activity generation. Their relationships with growth factors in matrices are also discussed

Revisión bibliográfica acerca del tratamiento de furcas involucradas periodontalmente / A review of the literature about the treatment of periodontally involved furcations

El tratamiento de una furca involucrada es uno de los problemas más difíciles de resolver para el especialista en periodoncia. En el presente artículo se ha hecho un resumen de todos los posibles procedimientos que disponemos en la actualidad para el tratamiento de esta entidad patológica. De lo anterior se deduce que el criterio clínico del operador y la motivación del paciente es de suma importancia en el tratamiento a pesar de que no existe una técnica que sea la ideal. Es importante reconocer que se requiere de más investigación al respecto y a su vez desarrollar nuevas técnicas de tratamientos para resolver el problema de la furca involucrada periodontalmente

La fibronectina y la adherencia de microorganismos patógenos / Fibronectin and the adherence of pathogenic microorganisms

La fibronectina (Fn) es uno de los principales componentes de la superficie celular, las matrices extracelulares y el plasma. La constituyen un dímero con dos cadenas polipeptícas de 250 kDa. Su estructura primaria está formada con base en unidades de repetición, originando los dominios de unión a diversas moléculas. La integrina Ó ß participa como el principal receptor celular de Fn. La fibronictina participa en procesos inmunológicos de fagocitosis, inflamación y opsonización, favoreciendo la depuración de bacterias y retos celulares. Juega un papel relevante en la cicatrización durante la hemostásis. En la superficie celular puede unirse a diferentes microorganismos, favoreciendo su colonización, siendo la primera etapa en la epatogénesis de diversas enfermedades infecciosas. En Staphylococcus aureus la proteína FnBp une al fragmento de 29 kDa de amino terminal de la Fn, sitio comparativo por Streptococcus pyogenes donde la proteína Sfb parece ser el ligando de la bacteria y no el ácido lipoteicóico (ALT). La Fn favorece la adherencia de bacterias gram positivas, su ausencia en la otofaringe favorece la colonización de bacterias gram negativas. Especies bacterianas de la cavidad orofaringea provocan la proteólisis de Fn y pueden participar indirectamente en la regulación de la flora cuando afectan los niveles de Fn en las superficies celulares. Treponema pallidum se une al sitio de reconocimiento celular de la Fn mediante una proteína semejante a la integrina (B 1) Entamoeba histolytica y schistosoma provocan una degradación de la Fn para poder invadir los tejidos epiteliales. Los parásitos intracelulares como Leishmania y Trypanosoma cruzi se adhieren a la Fn, utilizándola para facilitar su entrada a las células que infectan. La Fn puede unir virus y partículas virales favoreciendo la acción depuradora en este tipo de infecciones. Su amplia distribución en el organismo y su multifunsionalidad la hacen ser una proteína determinante en los procesos homeostásicos y de gran interés como un determinante en colonización e infección

Plasma fibronectin in type I and type II diabetic patients and its relation to diabetic macro and microangiopathy

This study included three groups of subjects: Group A, comprised 15 insulin dependent diabetics, group B, comprised 15 non-insulin dependent diabetics, and group C, comprised 15 normal healthy subjects [control]. All of them were subjected to a thorough history taking, clinical examination, fundus examination, plasma fibronectin level, fasting and 2-hour postprandial blood glucose. In conclusion, it was found that plasma fibronectin levels were higher in all diabetic groups with or without diabetic microangiopathy compared with control group [diabetics as whole, type 1 diabetics, type 2 diabetics, diabetics with retinopathy and diabetics with diabetic foot]. Also, plasma fibronectin levels were found higher in patients with diabetic retinopathy compared with those without retinopathy and higher in patients with diabetic foot compared with those without diabetic foot which agrees with the theory suggesting that plasma fibronectin is higher in diabetic microangiopathy. Plasma fibronectin concentration exhibited no significant correlation with fasting or 2-hour post prandial blood glucose or duration of diabetes. So, fibronectin might be considered as an indication of microvascular damage in diabetes mellitus and can represent an important approach in the study and prevention of diabetic microangiopathic disorders