This study compares the effect of tooth clenching and grinding on sternocleidomastoid electromyographic (EMG) activity during different laterotrusive jaw posture tasks. The study included 28 healthy subjects with natural dentition and bilateral molar support, 14 with bilateral canine guidance and 14 with bilateral group function. Bipolar surface electrodes were located on the left and right sternocleidomastoid muscles. EMG activity was recorded during the following tasks: (A) eccentric grinding from intercuspal position to the right lateral edge-to-edge contact position; (B) clenching in right edge-to-edge lateral contact position; (C) concentric grinding from right lateral edge-to-edge contact position to intercuspal position. On the working side, activity in the task C was significantly higher than in tasks A and B in subjects with canine guidance, whereas no significant differences were observed between tasks in subjects with group function. On the nonworking side, activity was significantly lower during task A than in tasks B and C, in both occlusal schemes (mixed model with unstructured covariance matrix). When comparing by side, EMG activity was significantly lower during task B on the working side than on the nonworking side. However, there were no significant differences during tasks A and C. The EMG activity was significantly lower with canine guidance than group function on the working side during tasks A, B, and C, and on the nonworking side during tasks B and C. These results could explain muscular symptoms in the sternocleidomastoid muscles if the subject is experiencing parafunctional habits while awake and/or during sleep that exceed the individual's adaptation capability.

Antecedentes: la inmunodeficiencia común variable se distingue por la ausencia de isohemaglutininas y disminución de al menos dos desviaciones estándar de las concentraciones normales de inmunoglobulinas. Su tratamiento incluye administrar inmunoglobulina, con mayor frecuencia intravenosa (IgIV). Un efecto adverso severo es la posible insuficiencia renal secundaria a la administración de preparados que contienen sacarosa. Estos pacientes muestran reducción de peso, disminución de masa muscular asociada con trastornos gastrointestinales y con bronquiectasias que limitan su actividad física. Existen diversas fórmulas para determinar la tasa de filtración glomerular, comparamos las más utilizadas para determinar la más adecuada en esta población.Objetivo: determinar la concordancia entre la tasa de filtración glomerular mediante la fórmula MDRD, CKD-EPI y Cockroft-Gault y la obtenida a través de la depuración de creatinina en orina de 24 horas en pacientes con inmunodeficiencia común variable tratados con inmunoglobulina intravenosa.Pacientes y método: estudio transversal, observacional y descriptivo que incluyó a 19 pacientes con inmunodeficiencia común variable, 12 mujeres y 7 hombres, con edad promedio de 36 años. Se aplicó estadística descriptiva con reporte de media, mediana y desviación estándar. Para medir la concordancia de las mediciones para las variables cuantitativas se usó el coeficiente de correlación intraclase y para determinar la concordancia entre los estadios de la función renal con las diferentes fórmulas se calculó el índice de Kappa.Resultados: los valores del coeficiente de correlación intraclase mostraron una concordancia buena entre la depuración de creatinina en orina de 24 h y CKD-EPI, concordancia mediocre con MDRD y nula con la fórmula Cockroft-Gault.Conclusiones: la tasa de filtración glomerular obtenida con CKD-EPI mostró parcialmente ser de mayor utilidad, con una correlación buena en relación con la depuración de creatinina en orina de 24 horas. Se recomienda su uso rutinario sobre las otras fórmulas en pacientes de inmunodeficiencia común variable con sospecha de afección renal secundaria a la administración de inmunoglobulina intravenosa.

Objectives: To determine if the starting time of chemotherapy influences on illness-free survival and general survival in a cohort of Mexican patients with breast cancer. MethOds: A prospective study over 5 years was performed on 88 women with breast cancer from the National Medical Centre "La Raza" of the Mexican Institute of Social Security (IMSS) with the following characteristics: stages I-III and positive criteria for adjuvant chemotherapy. The time range for the chemotherapy administration was 0 to 2, 3 and > 4 months. The analysis was performed regarding chemotherapy administration time interval using a Kaplan-Meier estimator. The Cox model was adjusted to see the relationships between the global survival and the oestrogen and progesterone hormone receptor variables and HER2/NEU as well as their basal characteristics. Results: For both IFS and GS there was a significantly statistical difference on the survival distributions related to starting time of chemotherapy which had a higher probability from a range of 0 to 2 months (median GS 59 months median IFS 49 months; p-value< 0.001). Regarding general survival, the hormonal receptors for oestrogen, progesterone and HER2/NEU do not influence on the Cox model (p-value= 0.137, 0.823, 0.524 respectively); for the Cox model with basal characteristics, age, pathological state and time interval between surgery and chemotherapy influenced significantly on GS (p-value< 0.05) cOnclusiOns: The probability of survival for IFS and GS improve when chemotherapy is administered within the first 2 months after surgery. Also, there was a greater risk for GS when time interval between surgery and chemotherapy was prolonged. This delay for the starting time of chemotherapy will impact without a doubt in the health systems´ economy, generating more expenses for attention.