Regulation of fast skeletal muscle activity by SERCA1 vicinal-cysteines.

During prolonged skeletal muscle contractions free radicals are produced that may lead to fatigue. Vicinal cysteines, known as a Vicinal-thiol groups react preferentially among them depending on redox potential. Therefore, we examined the role of VT groups on the activity and conformational changes of sarcoplasmic reticulum (SR) Ca(2+)-ATPase (SERCA1) from rabbit skeletal muscle isolated SR, by selective oxidation-reduction of VT-groups. After Ca(2+) is released from the SR to start contraction, SERCA1 pumps this cytosolic Ca(2+) back to the SR leading to muscle relaxation. Phenylarsine oxide (PAO) reacts selectively with VT-proteins forming dithioarsines, which are stable but exchanges rapidly with 2,3-dimercaptopropanol (BAL). When 0.1 mM PAO is added to isolated SR, 60 and 67% inhibition of SERCA1 hydrolytic and Ca(2+) uptake activities, respectively is observed. ATPase activity was fully reversible with 1 mM BAL. The SERCA1 thermal inactivation determined from isolated SR from muscle at rest showed a single transition for inactivation (T(i)) at 49 +/- 1.12 degrees C. In the presence of 0.1 mM PAO, SERCA1 shows two transitions at T(i) 34 +/-0.9 degrees C and at 27 +/-1.2 degrees C. The thermal denaturation profile of SERCA1 from muscle at rest, showed two transitions at T(m) = 51.5 +/-1.3 degrees C and 63 +/-1.02 degrees C related to nucleotide and Ca(2+) binding domains, respectively. Whereas isolated SR obtained after a protocol of tetanic stimulation to produce muscle fatigue, showed three transitions in the SERCA1 denaturation profile similar to the effect of PAO, addition of 1 mM BAL reverted the effect of fatigue on SERCA1 denaturation profile. These results indicate a mechanism relating VT group's oxidation to muscle fatigue.

Diámetro de la columna de aire de cuerdas vocales como predictor de estridor laríngeo postextubación / Diameter of the vocals cord air column as a laryngeal stridor predictor post-extubation / Diâmetro da coluna de ar das cordas vocais como predictor do estridor laringeo pós-extubação

Resumen: Objetivo: Correlacionar la presencia de estridor laríngeo con el diámetro de la columna de aire de cuerdas vocales a través de ultrasonido de vía aérea en pacientes intubados en UCI. Material y métodos: Descriptivo. Se midió el diámetro de la columna de aire de cuerdas vocales con ultrasonido lineal en pacientes con weaning, se tomaron cinco grupos de acuerdo con el diámetro: < 5 mm, 5.1-5.5 mm, 5.5-6.0 mm, 6.1-6.4 y > 6.5 mm. Se observó la presencia o la ausencia de estridor laríngeo. Se realizó análisis estadístico tipo frecuencias y porcentajes, con variables de tipo cuantitativo se determinaron medidas de tendencia central, media, moda y desviación estándar. Resultados: Se incluyeron 30 pacientes, la media de edad fue de 39.5 años, una desviación estándar de 18.666, 78.6% de los pacientes permaneció intubado por un periodo de 2-5 días, 83.3% tuvo extubación exitosa, cinco fracasaron a la extubación, dos de ellos por estridor laríngeo, que correspondió a 6.7% con un diámetro de 5.1-5.5 mm., Pearson 0.48. Conclusiones: La medición del diámetro de la columna de aire de cuerdas vocales es una herramienta útil para el médico intensivista como predictor de estridor laríngeo postextubación.

Abstract: Objective: To correlate the presence of laryngeal stridor with the diameter of the vocal cord air column through airway ultrasound in patients intubated in the ICU. Material and methods: Descriptive. The diameter of the vocal cord air column was measured with linear ultrasound in weaning patients, five groups were taken according to the diameter: < 5 mm, 5.1-5.5 mm, 5.5-6.0 mm, 6.1-6.4 and > 6.5 mm. The presence or absence of laryngeal stridor was observed. Statistical analysis was carried out, such as frequencies and percentages, with variables of a quantitative type, measures of central tendency, mean, mode, and standard deviation were determined. Results: Thirty patients were included, the mean age was 39.5 years, a standard deviation of 18.666, 78.6% of the patients remained intubated for a period of 2-5 days, 83.3% presented successful extubation, five presented failure to extubation, two of them due to laryngeal stridor, which corresponded to 6.7% with a diameter of 5.1-5.5 mm., Pearson 0.48. Conclusions: The measurement of the diameter of the vocal cord air column is a useful tool for the intensivist physician as a predictor of laryngeal stridor after extubation.

Resumo: Objetivo: Correlacionar a presença de estridor laríngeo com o diâmetro da coluna aérea das cordas vocais por meio de ultrassonografia das vias aéreas em pacientes intubados na UTI. Material e métodos: Descritivo. O diâmetro da coluna de ar das cordas vocais foi medido com ultrassonografia linear em pacientes com desmame ventilatório. 5 grupos foram selecionados de acordo com o diâmetro: < 5 mm, 5.1-5.5 mm, 5.5-6.0 mm, 6.1-6.4 e > 6.5 mm. Observou-se a presença ou ausência de estridor laríngeo. Realizou-se análise estatística tipo frequências e porcentagens, com variáveis de tipo quantitativo, foram determinadas medidas de tendência central, média, moda e desvio padrão. Resultados: Foram incluídos 30 pacientes, a média de idade foi de 39.5 anos, um desvio padrão de 18.666, 78.6% dos pacientes permaneceram intubados por um período de 2-5 dias, 83.3% apresentaram sucesso na extubação, 5 apresentaram falha na extubação, 2 deles por estridor laríngeo, correspondendo a 6.7% com diâmetro de 5.1 a 5.5 mm. Pearson 0.48. Conclusão: A medida do diâmetro da coluna aérea das cordas vocais é uma ferramenta útil para o médico intensivista como preditor de estridor laríngeo após a extubação.

Pérdida recurrente del embarazo e hipertensión pulmonar idiopática / Recurrent pregnancy loss and idiopatic pulmonary hypertension

Resumen La pérdida recurrente del embarazo ocurre cuando una mujer tiene 2 ó más pérdidas de embarazos clínicos antes de las 20 semanas de gestación. Existen múltiples factores de riesgo relacionados con este padecimiento, entre ellos, la presencia de Hipertensión Pulmonar (HP) se vincula con elevada mortalidad (30-56% de los casos) y riesgo de abortos entre las semanas 9 y 12 de gestación. No se conoce con precisión la frecuencia de asociación entre las condiciones clínicas referidas. Presentamos el caso de una mujer de 31 años de edad que ingresó al hospital con un aborto en evolución, en el periodo posterior al legrado evidencian Hipoxemia Grave e Insuficiencia Cardiaca Derecha; durante el abordaje diagnóstico se confirma que la causa primaria de la recurrencia de abortos se encuentra asociada con la presencia de Hipertensión Pulmonar Idiopática.

Abstract Recurrent pregnancy loss occurs whenever a woman has 2 or more miscarriages of their clinical pregnancy before 20 weeks of gestation. There are multiple risk factors relates to this condition, among, them, the presence of pulmonary hypertension (PH) is linked with high mortality (30-56% of cases) and risk of miscarriages between 9 weeks and 12 of gestation. The prevalence of both conditions are not well known. Here, we present the case of a 31 year-old women who was admitted to the hospital with an abortion in evolution, immediately after the curettage, the patient exhibit severe hypoxemia in association with Right Heart Failure; the medical approach established that the primary cause of recurrent abortions was an uncontrolled idiopathic pulmonary hypertension.