Preliminary study on parameterization of raw electrical bioimpedance data with 3 frequencies.

This study tests the geometrical parameterization method for Electrical Bio-Impedance Spectroscopy (EBIS) readings previously proposed by one of the authors. This method uses the data of just three frequencies (therefore called 3P method). The test was carried out by the analysis of parameterization from 26 spectra (selected from 13 data sets) by the non-linear square (NLS) method, the 3P method and a combination of the two (3P-NLS). Additionally, the behaviour of the 3P method for 4 levels of noise and 3 different ways of segmenting the spectra were also explored with a MATLAB simulation of 400 spectra. Finally, a system for the classification of EBIS readings is presented, based on deviations of the raw data from the semi-circle obtained by the parameterization methods. Overall, the results suggest a very good performance of the 3P method when compared with the other two. The 3P method performs very well with levels of noise of 1 and 2%, but performs poorly with levels of noise of 5% and 10%. The results support the idea that the 3P method could be used with confidence for the parameterization of EBIS spectra, after the selection of three adequate frequencies according to specific applications.

A geometrical method for modeling bioelectrical impedance measurements and remove the hook effect deviations.

OBJECTIVE: to describe a simple and straightforward method to calculate the circle parameters that can be used to fit Electrical Bioimpedance Spectroscopy (EBIS) raw data to the complex plane and remove the hook effect, a deviation of that model especially seen at higher frequencies and considered as an artifact due to instrumental limitations. APPROACH: under the assumption that raw EBIS data in the middle frequencies best represent the beta dispersion, the authors of this article propose a geometrical procedure to calculate parameters for this dispersion and remove the hook effect. For this purpose, data obtained with two different devices were used with apparently very good results. MAIN RESULTS: the results of this study suggest that circle parameters for the beta dispersion can be obtained, but, also, that the residuals of the hook effect correction seem to adjust to a circle and, therefore, they could also be parameterized using the same approach. SIGNIFICANCE: the method proposed in this article is very easy to perform and could help end EBIS users not familiar with mathematical models and fitting processes, to better understand and interpret their data.

Ascitis pancreática traumática, manejo conservador: reporte de un caso / Post-traumatic pancreatic ascites, conservative management: a case

Resumen Objetivo: Presentar el caso de un paciente masculino adulto joven, con ascitis pancreática secundaria a lesión del conducto pancreático por trauma abdominal cerrado, tratado con éxito con terapia conservadora. Materiales y Método: Datos e imágenes recopilados de la historia clínica del Hospital Universitario de Santander, previo consentimiento informado. Resultados: Sexo masculino de 21 años con antecedente de trauma abdominal cerrado, quien consulta por distensión, dolor abdominal progresivo y pérdida de peso no cuantificada. Ante sospecha de lesión de conducto pancreático se solicitó pancreatografía por resonancia magnética que evidencia una alteración del segmento proximal del conducto pancreático principal asociado a lesión quística en el borde anterior de la unión de la cabeza con el cuerpo pancreático. Se decidió manejo conservador por 4 semanas con colocación de dren abdominal, reposo intestinal, asociado a nutrición parenteral total y análogos de somatostatina. Discusión: Un 5% del trauma abdominal cerrado puede provocar pancreatitis y fugas en el conducto pancreático. Conclusión: La lesión del conducto pancreático principal debe sospecharse en todos los pacientes con trauma abdominal cerrado. El manejo debe realizarse con una planificación cuidadosa y exhaustiva.

Aim: To present the case of a young adult male patient, with pancreatic ascites secondary to pancreatic duct injury due to blunt abdominal trauma, treated successfully with conservative therapy. Materials and Method: Data and images were obtained from the clinical chart of the "Hospital Universitario de Santander" with prior informed consent. Results: 21-year-old male patient with a blunt abdominal trauma background, who consulted for distension, progressive abdominal pain, and subjective weight loss. Due to suspicion of a pancreatic duct injury, a magnetic resonance cholangiopancreatography was requested, which showed an alteration of the proximal segment of the main pancreatic duct associated with a cystic lesion at the anterior border of the junction between the pancreatic head and body. Treatment consisted of a 4-week conservative therapy with the placement of an abdominal drain, bowel rest, associated with total parenteral nutrition and somatostatin analogs. Discussion: A 5% of blunt abdominal trauma can cause pancreatitis and pancreatic duct leaks. Conclusión: Pancreatic duct injury should be suspected in every patient with blunt abdominal trauma. Management must be done with careful and thorough planning.

Nonalcoholic fatty liver disease is associated with insulin resistance in a young Hispanic population.

OBJECTIVE: To investigate whether nonalcoholic fatty liver disease (NAFLD) is associated with insulin resistance (IR) in a young Hispanic population. METHODS: A cross-sectional study was performed in Bogotá, Colombia, during 2006 in 263 males from the Colombian Air Force (age range 29-54 years). Anthropometric measurements and biochemical determinations (glycemia, lipid profile, insulin, and HOMA-IR) were obtained in order to determine the presence of metabolic syndrome (MS) criteria and insulin resistance in this population. In addition, ultrasound studies were performed to evaluate the presence of NAFLD. RESULTS: NAFLD was detected in 26.6% (n=70) of the subjects. Thirty four individuals had complete MS criteria (48.5%). The presence of NAFLD was associated with higher insulin levels (11.0±5.1 vs. 6.6±3.6, p=0.001), and its prevalence increased from 11% (n=8), to 24% (n=17) to 64% (n=45) from the lowest to the highest HOMA-IR tertile. Body mass index, triglycerides and subcutaneous and visceral fat were found to be independent predictors of NAFLD. CONCLUSIONS: These results suggest that NAFLD is associated with insulin resistance and extrahepatic adiposity in nondiabetic young Hispanic population.