Polymorphisms of the noggin gene and mandibular micrognathia: a first approximation

Mandibular micrognathia is a deficiency in mandibular growth that prevents tooth contact during mastication, interferes with phonation and even causes sleep apnea. Studies show that mutant mice for chd (chordin) and nog (noggin) genes, which are modulators of the Bone Morphogenic Protein (BMP), had mandibular defects ranging from mandibular hypoplasia to micrognathia and agnathia. The human NOG gene was the first BMP antagonist identified and it is essential for various late events in mandibular development, which require modulation of the BMP activity. The aim of this work was to determine the presence of NOG gene polymorphisms in families with mandibular micrognathia and analyze its phenotype. Four families with mandibular micrognathia were included in this study. Blood samples were taken from the participating individuals through venipuncture and DNA was extracted. The fragments of interest were amplified using the Polymerase Chain Reaction (PCR) and the Single Nucleotide Polymorphisms (SNPs) of the NOG gene reported in the NCBI data base were analyzed through direct sequencing. The SNP rs1348322 was present in homozygote form in the subjects from all the families, where Cytosine is changed to Adenine in position 112 of the exon of the NOG gene. The SNP rs 1236187 did not show any clear result. This result suggests that there may be population polymorphism, or markers that are seldom polymorphic for our population. It is therefore necessary to continue with the search for the relationship of the NOG gene with mandibular micrognathia.

El micrognatismo mandibular, deficiencia en el crecimiento de la mandibula, no permite que los dientes entren en contacto durante la masticacion, interfiriendo con la fonacion y produciendo inclusive apnea del sueno. Estudios con ratones mutantes para el gen chordin (chd) o noggin (nog) moduladores de las proteinas morfogenicas oseas (BMP) presentaron defectos mandibulares, que van desde hipoplasia mandibular, pasando por micrognatia hasta agnatia. El gen NOG humano fue el primer antagonista de BMP identificado y es esencial para varios eventos tardios del desarrollo mandibular, que requieren modulacion de la actividad de las BMP. El objetivo del trabajo fue determinar la presencia de polimorfismos del gen NOG en pacientes con micrognatismo mandibular y analizar su fenotipo. Se tomaron 4 familias con micrognatismo mandibular, muestras de sangre fueron tomadas por venopuncion a los individuos participantes, el ADN fue extraido, se realizo la amplificacion de los fragmentos correspondientes a los polimorfismos rs 1236187 y rs 1348322 mediante PCR (Reaccion en Cadena de la Polimerasa) y se analizaron los SNPs del gen NOG reportados en la base de datos NCBI, mediante secuenciacion directa. El SNP rs 1348322, se presento en forma homocigota en los individuos de todas las familias, donde se da el cambio de una Citosina por una Adenina en la posicion 112 del exon del gen NOG. El SNP rs 1236187, no arrojo ningun resultado en forma clara. Este resultado sugiere que posiblemente pueden tratarse de polimorfismos poblacionales, o de marcadores poco polimorficos para nuestra poblacion, por lo tanto es necesario continuar en la busqueda de la relacion del gen NOG con el micrognatismo mandibular.

Influencia del sistema nitridérgico en la respuesta contráctil a fenilefrina de anillos de vasos usados en revascularización coronaria / Modification of phenylephrine induced contraction of human vessel rings by L-arginine and L-arginine methyl ester

Background: Endothelial dysfunction is associated to a lower production of nitric oxide and a reduction of endothelium mediated vasodilation. Aim: To study the effects of pharmacological agents that modify nitric oxide synthetase (NOS) activity on tension changes induced by phenylephrine in rings of internal mammary and radial arteries and saphenous vein. Material and methods: Vessel rings of 7 to 10 mm length were obtained from 32 patients subjected to coronary vascular surgery Fourteen samples of radial artery, 12 samples of internal mammary artery and 15 samples of saphenous vein were obtained. A maximal contraction was induced with KC1 and dose response curves for phenylephrine (FE) in the absence or presence of L-arginine and L-arginine methyl ester (L-NAME), were constructed. Results: The tension induced by FE in internal mammary artery and saphenous vein reached a maximum, near 90 percent of 80 mM KCl-induced contraction, but in the radial artery, it reached a maximum of 63 percent (p <0.05). In all vessels, the dose response curves were significantly shifted to the right by L-arginine and to the íeft by L-NAME. Conclusions: Pre-incubation of human rings with L-ARG or L-NAME, changed the response to FE induced contraction, which may be related to different degrees of endothelial nitric oxide production or NO sensitivity. The basal NO production in radial artery seems to be larger than the other vessels.

Sindrome de Beckwith Weidemann: reporte de caso en el Hospital Universitario San Ignacio y revision de la literatura / Beckwith Weidemann syndrome: one case in Hospital Universitario San Ignacio and revisal of literature

El síndrome de Beckwith Weidemann (SBW) es uno de los síndromes de sobrecrecimiento en el que sus manifestaciones más frecuentes son la macrosomia, los defectos de pared abdominal, la macroglosia y la hipoglicemia neonatal temprana. Su diagnóstico temprano es importante para el manejo de los bajos niveles séricos de glucosa, los cuales se asocian a retardo del desarrollo psicomotor posterior. Los pacientes con este síndrome tienen un riesgo mayor de desarrollar neoplasias especialmente tumor de Wilms. La etiología de esta entidad es la alteración en los patrones de metilación de los alelos en el llpl5.5 de genes que regulan el crecimiento y la división celular. El seguimiento de estos pacientes es necesario por el riesgo aumentado que tienen de desarrollar neoplasias, especialmente en quienes presentan hemihipertrofia y nefromegalia