Hepatitis C Virus positivity prediction from serum samples using NIRS and L1-penalized classification.

AIMS: The hepatitis C virus (HCV) has developed a strategy to coexist with its host resulting in varying degrees of tissue and cell damage, which generate different pathological phenotypes, such as varying degrees of fibrosis, cirrhosis, and hepatocellular carcinoma (HCC). However, there is no integrated information that can predict the evolutionary course of the infection. We propose to combine Near-infrared spectroscopy (NIRS) and machine learning techniques to provide a predictive model. In this work, we propose to discriminate HCV positivity in biobank patient serum samples. METHODS: 126 serum samples from 38 HCV patients in different stages of the disease were obtained from the Biobank of Hospital Universitario Fundación Alcorcon. NIRS spectrum was captured by a FT-NIRS Spectrum 100 (Perkin Elmer) device in reflectance mode. For each patient, the HCV positivity was identified (PCR) and labeled as detectable =1 and undetectable =0. We propose an L1-penalized logistic regression model to classify each spectrum as positive (1) or negative (0) for HCV presence (x). The regularization parameter is selected using 5- fold cross-validation. The penalized model will induce sparsity in the solution so that only a few relevant wavelengths will be different from zero. RESULTS: L1-penalized logistic regression model provided 167 wavelengths different from zero. The accuracy on an independent test set was 0.78. CONCLUSIONS: We present a straightforward promising approach to detect HCV positivity from patient serum samples combining NIRS and machine learning techniques. This result is encouraging to predict HCV progression, among other applications. Clinical relevance- We presented a simple while promising approach to use machine learning and NIRS to analyze viral presence on sample serums.

Thrombocytopenia and anaphylaxis secondary to heparin in a hemodialysis patient.

AIMS: We describe a rare case of anaphylaxis and thrombocytopenia whose cause was heparin used during hemodialysis sessions. CASE REPORT: A 77-year-old woman suffered five consecutive episodes of vomiting, tachypnea, wheezing or rales, immediately after initiating hemodialysis. In the first of these episodes, arterial pressure was undetectable. In all of the episodes there was evidence of the presence of hypoxia (always below 60 mmHg) and thrombocytopenia (always below l00,000/microl,, with partial platelets recovery among episodes. The episodes started immediately after hemodialysis sessions and heparin infusion; either sodium heparin or enoxaparin was used. Utilization of different filters was not able to stop the episodes. These were stopped when a switch from heparin to hirudin was tested. Tryptase levels, as a marker of mast cells activation and anaphylaxis, were not increased in two of the episodes which were assessed. IgG antibodies against heparin-PF4 complex was detected at high levels. DISCUSSION: A diagnosis of concomitant anaphylaxis and thrombocytopenia caused by sodium heparin and a low-molecular weight heparin (enoxaparin) were assumed.

[Determination of theophylline blood levels by a rapid immunoenzyme method ( "Accu-Level"): results in 83 cases]. / Determinación de teofilinemias por método rápido inmunoenzimático ("Accu-Level"): resultados en 83 casos.

We report the results of the use of the "Accu-level" method for the rapid measurement of theophylline blood levels in a health center, so as to evaluate it for the routine practice of family doctors. The study included 83 patients receiving sustained effect theophylline preparations from May to September 1988. The accuracy of the method in the interassay evaluation (repetitivity) showed a variation coefficient of 7.92%, whereas in the intraassay evaluation (reproducibility) the coefficients were lower than 5%. The correlation study with the EMITT method showed a correlation coefficient of r = 0.9967. The present results, the easy use of the assay by the family doctor and the small technical equipment which is required support the use of this method for the monitorization of blood theophylline levels in outpatients.