Diagnosis of Obstructive Sleep Apnea in Patients with Associated Comorbidity.

Obstructive sleep apnea (OSA) is a heterogeneous disease with many physiological implications. OSA is associated with a great diversity of diseases, with which it shares common and very often bidirectional pathophysiological mechanisms, leading to significantly negative implications on morbidity and mortality. In these patients, underdiagnosis of OSA is high. Concerning cardiorespiratory comorbidities, several studies have assessed the usefulness of simplified screening tests for OSA in patients with hypertension, COPD, heart failure, atrial fibrillation, stroke, morbid obesity, and in hospitalized elders.The key question is whether there is any benefit in the screening for the existence of OSA in patients with comorbidities. In this regard, there are few studies evaluating the performance of the various diagnostic procedures in patients at high risk for OSA. The purpose of this chapter is to review the existing literature about diagnosis in those diseases with a high risk for OSA, with special reference to artificial intelligence-related methods.

Assessment of Nocturnal Autonomic Cardiac Imbalance in Positional Obstructive Sleep Apnea. A Multiscale Nonlinear Approach.

Positional obstructive sleep apnea (POSA) is a major phenotype of sleep apnea. Supine-predominant positional patients are frequently characterized by milder symptoms and less comorbidity due to a lower age, body mass index, and overall apnea-hypopnea index. However, the bradycardia-tachycardia pattern during apneic events is known to be more severe in the supine position, which could affect the cardiac regulation of positional patients. This study aims at characterizing nocturnal heart rate modulation in the presence of POSA in order to assess potential differences between positional and non-positional patients. Patients showing clinical symptoms of suffering from a sleep-related breathing disorder performed unsupervised portable polysomnography (PSG) and simultaneous nocturnal pulse oximetry (NPO) at home. Positional patients were identified according to the Amsterdam POSA classification (APOC) criteria. Pulse rate variability (PRV) recordings from the NPO readings were used to assess overnight cardiac modulation. Conventional cardiac indexes in the time and frequency domains were computed. Additionally, multiscale entropy (MSE) was used to investigate the nonlinear dynamics of the PRV recordings in POSA and non-POSA patients. A total of 129 patients (median age 56.0, interquartile range (IQR) 44.8-63.0 years, median body mass index (BMI) 27.7, IQR 26.0-31.3 kg/m2) were classified as POSA (37 APOC I, 77 APOC II, and 15 APOC III), while 104 subjects (median age 57.5, IQR 49.0-67.0 years, median BMI 29.8, IQR 26.6-34.7 kg/m2) comprised the non-POSA group. Overnight PRV recordings from positional patients showed significantly higher disorderliness than non-positional subjects in the smallest biological scales of the MSE profile (τ = 1: 0.25, IQR 0.20-0.31 vs. 0.22, IQR 0.18-0.27, p < 0.01) (τ = 2: 0.41, IQR 0.34-0.48 vs. 0.37, IQR 0.29-0.42, p < 0.01). According to our findings, nocturnal heart rate regulation is severely affected in POSA patients, suggesting increased cardiac imbalance due to predominant positional apneas.

Malignant Infantile osteopetrosis. / Osteopetrosis infantil maligna.

INTRODUCTION: Malignant Infantile Osteopetrosis (MIOP) is a rare and severe genetic disorder due to abnormal osteoclast activity. OBJECTIVE: To report an infant who presented Malignant Infantile Osteopetrosis, reviewing the most relevant diagnostic and therapeutic aspects. CLINICAL CASE: A ten- month-old male infant with diagnosis of MIOP confirmed after presenting thrombocytopenia and visceromegaly. He was the first child of non-consanguineous parents, and among the findings, he presented severe hepatosplenomegaly, thrombocytopenia, and anemia; visual and hearing impair ment, and repeated infections. The diagnosis was confirmed by genetic study, which identified two heterozygous mutations in the TCIRG1 gene. Hematopoietic stem cells were transplanted without hematological recovery. The patient died due to occlusive venous disease. DISCUSSION: MIOP is a rare, severe, and early-onset disease, with a high rate of suspicion necessary in the presence of hepa- tosplenomegaly and bone marrow failure. Early diagnosis and hematopoietic stem cells transplanta tion are the only potentially therapeutic interventions of this lethal entity.

Deformability properties of timolol-loaded transfersomes based on the extrusion mechanism. Statistical optimization of the process.

The purpose of this work was to analyze the deformability properties of different timolol maleate (TM)-loaded transfersomes by extrusion. This was performed because elastic liposomes may contribute to the elevation of amount and rate of drug permeation through the corneal membrane. This paper describes the optimization of a transfersome formulation by use of Taguchi orthogonal experimental design and two different statistical analysis approaches were utilized. The amount of cholesterol (F1), the amount of edge-activator (F2), the distribution of the drug into the vesicle (F3), the addition of stearylamine (F4) and the type of edge-activator (F5) were selected as causal factors. The deformability index, the phosphorous recovery, the vesicle size, the polydispersity index, the zeta potential and percentage of drug entrapped were fixed as the dependent variables and these responses were evaluated for each formulation. Two different statistical analysis approaches were applied. The better statistical approach was determined by comparing their prediction errors, where regression analysis provided better optimized responses than marginal means. From the study, an optimized formulation of TM-loaded transfersomes was prepared and obtained for the proposed ophthalmic delivery for the treatment of open angle glaucoma. It was found that the lipid to surfactant ratio and type of surfactant are the main key factors for determining the flexibility of the bilayer of transfersomes. From in vitro permeation studies, we can conclude that TM-loaded transfersomes may enhance the corneal transmittance and improve the bioavailability of conventional TM delivery.

Radiopharmaceuticals in positron emission tomography: present situation and future perspectives. / Radiofármacos utilizados en la tomografía por emisión de positrones: presente y perspectivas de futuro.

Positron emission tomography (PET) is an imaging technique that has grown greatly in recent years. PET is considered a fundamental tool in oncology, and it also has indications in other fields such as neurology and cardiology. Although 18F-fluorodeoxyglucose (18F-FDG) is the radiopharmaceutical most widely used in PET, the availability of new radiotracers has been a key element in the expansion of the use of PET. These new radiopharmaceuticals have made it possible to study different biological targets that are essential for obtaining greater knowledge and better characterization of different diseases and have thus contributed to the research and development of different therapeutic agents. This article provides a description of different PET radiopharmaceutical, structured according to their areas of application. Some of these radiotracers are already commercially available, whereas others are still under research or pending approval by regulatory bodies.

Radioembolization in patients with hepatocellular carcinoma: a series of 53 cases.

OBJECTIVE: To contribute our results to increase the scientific evidence about the use of radioembolization in the management of patients with hepatocellular carcinoma. MATERIAL AND METHODS: This retrospective review included 53 patients with hepatocellular carcinoma treated with radioembolization at our center. Patients were classified according to the BCLC algorithm in detail according to their Child-Pugh functional status. We analyzed survival using the Kaplan-Meier method. We used Cox regression analysis to determine clinically significant parameters, including the doses administered in the parameters studied. RESULTS: Patients ranged in age from 28 to 86 years (mean, 60 years). A total of 61 procedures were done. The mean activity administered was 2.8GBq (0.7-6.4GBq), with a mean dose of 229.9Gy (74-425.9Gy) administered in the tumor. Progression-free survival was 6.7 months and overall survival was 12.8 months. Differences in disease-free survival according to BCLC and Child-Pugh classification were not significant (p=0.848 and p=0.252, respectively). The clinical parameters that were significantly different with respect to overall survival were bilirubin levels (p<0.001), pretreatment transaminase levels (AST) (p=0.022), Child-Pugh subclassification (p=0.003), and dose administered in the tumor (p=0.001). Only one patient had a severe adverse reaction, developing posttreatment liver failure resulting in death. CONCLUSIONS: Radioembolization is safe and efficacious in the treatment of patients with hepatocellular carcinoma. Liver function and the doses received by the tumor are key parameters for the efficacy of treatment. The increase in the scientific evidence supports the inclusion of this technique in treatment guidelines.

Simulated gastrointestinal digestion of polylactic acid (PLA) biodegradable microplastics and their interaction with the gut microbiota.

The accumulation of microplastics (MPs) in the environment as well as their presence in foods and humans highlight the urgent need for studies on the effects of these particles on humans. Polylactic acid (PLA) is the most widely used bioplastic in the food industry and medical field. Despite its biodegradability, biocompatibility, and "Generally Recognized As Safe" (GRAS) status, recent animal model studies have shown that PLA MPs can alter the intestinal microbiota; however, to date, no studies have been reported on the possible gut and health consequences of its intake by humans. This work simulates the ingestion of a realistic daily amount of PLA MPs and their pass through the gastrointestinal tract by combining the INFOGEST method and the gastrointestinal simgi® model to evaluate possible effects on the human colonic microbiota composition (16S rRNA gene sequencing analysis) and metabolic functionality (lactic acid and short-chain fatty acids (SCFA) production). Although PLA MPs did not clearly alter the microbial community homeostasis, increased Bifidobacterium levels tended to increase in presence of millimetric PLA particles. Furthermore, shifts detected at the functional level suggest an alteration of microbial metabolism, and a possible biotransformation of PLA by the human microbial colonic community. Raman spectroscopy and field emission scanning electron microscopy (FESEM) characterization revealed morphological changes on the PLA MPs after the gastric phase of the digestion, and the adhesion of organic matter as well as a microbial biofilm, with surface biodegradation, after the intestinal and colonic phases. With this evidence and the emerging use of bioplastics, understanding their impact on humans and potential biodegradation through gastrointestinal digestion and the human microbiota merits critical investigation.

Development of resistance in Cronobacter sakazakii ATCC 29544 to thermal and nonthermal processes after exposure to stressing environmental conditions.

AIMS: The objective was to study the response of Cronobacter sakazakii ATCC 29544 cells to heat, pulsed electric fields (PEF), ultrasound under pressure (Manosonication, MS) and ultraviolet light (UV-C) treatments after exposure to different sublethal stresses that may be encountered in food-processing environments. METHODS AND RESULTS: Cronobacter sakazakii stationary growth-phase cells (30°C, 24h) were exposed to acid (pH 4·5, 1h), alkaline (pH 9·0, 1h), osmotic (5% NaCl, 1h), oxidative (0·5mmoll(-1) H(2) O(2), 1h), heat (47·5°C, 1h) and cold (4°C, 4h) stress conditions and subjected to the subsequent challenges: heat (60°C), PEF (25kVcm(-1) , 35°C), MS (117µm, 200kPa, 35°C) and UV-C light (88·55mWcm(-2), 25°C) treatments. The inactivation kinetics of C. sakazakii by the different technologies did not change after exposure to any of the stresses. The combinations of sublethal stress and lethal treatment that were protective were: heat shock-heat, heat shock-PEF and acid pH-PEF. Conversely, the alkaline shock sensitized the cells to heat and UV-C treatments, the osmotic shock to heat treatments and the oxidative shock to UV-C treatments. The maximum adaptive response was observed when heat-shocked cells were subjected to a heat treatment, increasing the time to inactivate 99·9% of the population by 1·6 times. CONCLUSIONS: Cronobacter sakazakii resistance to thermal and nonthermal preservation technologies can increase or decrease as a consequence of previous exposure to stressing conditions. SIGNIFICANCE AND IMPACT OF THE STUDY: The results help in understanding the physiology of the resistance of this emerging pathogen to traditional and novel preservation technologies.

Pulsed electric fields cause sublethal injuries in the outer membrane of Enterobacter sakazakii facilitating the antimicrobial activity of citral.

AIMS: The objective was to evaluate the relation of sublethal injury in the outer membrane of Enterobacter sakazakii to the inactivating effect of the combination of pulsed electric fields (PEF) treatments and citral. METHODS AND RESULTS: The occurrence of sublethal injury in the outer membrane was measured using selective recovery media containing bile salts. Loss of membrane integrity was measured by the increased uptake of the fluorescent dye propidium iodide (PI). PEF caused nonpermanent and permanent envelope permeabilization of Ent. sakazakii at pH 4·0. After PEF, most surviving cells showed transient cell permeabilization and sublethal injury in their outer membranes. The simultaneous application of a mild PEF treatment (100 pulses, 25 kV cm(-1) ) and 200 µl l(-1) of citral to cells suspended in pH 4·0 buffer at a final concentration of 10(7) cells per ml showed an outstanding synergistic lethal effect, causing the inactivation of more than two extra log(10) cycles. CONCLUSIONS: Our results confirm that the detection of sublethal injury in the outer membrane after PEF may contribute to the identification of the treatment conditions under which PEF may act synergistically with hydrophobic compounds such as citral. SIGNIFICANCE AND IMPACT OF THE STUDY: Knowledge about the mechanism of microbial inactivation by PEF will aid the establishment of successful combined preservation treatments.

[Application of ICRP-103 in the calculation of effective dose associated to nuclear medicine tests]. / Aplicación de los factores de ponderación de la Comisión Internacional de Protección Radiológica 103 en el cálculo de la dosis efectiva asociada a las exploraciones de Medicina Nuclear.

OBJECTIVE: Re-evaluate the effective dose (E) of typical nuclear medicine procedures using the new ICRP-103 weighting factors and the latest dosimetry data and relate E with Background Equivalent Radiation Time (BERT). MATERIAL AND METHODS: Effective dose associated with radiopharmaceuticals and nuclear medicine procedures has been calculated for the following ages: adult, 15, 10, 5 and 1 year. Dosimetry data have been extracted from ICRP-106, ICRP-80, ICRP-53 and/or manufacturer's brochure. RESULTS: The relationship of the data of effective dose associated with radiopharmaceuticals and explorations is shown. The new tissue weighting factors result in a decreased value of the effective dose, except in cases that particularly affect the breast, in which it increases. The effective dose associated with nuclear medicine procedures is in the range 0.1-60 mSv. BERT ranges from a few days to 20 years. The effective dose associated to tests in children is generally higher than the effective dose for an adult. CONCLUSIONS: The results shown in this paper are an updated collection of effective dose values for commonly used radiopharmaceuticals in nuclear medicine. Expressing the effective dose equivalent time in units of natural radiation helps to explain issues associated with radiation exposure to patients and healthcare personnel.

A machine learning-based test for adult sleep apnoea screening at home using oximetry and airflow.

The most appropriate physiological signals to develop simplified as well as accurate screening tests for obstructive sleep apnoea (OSA) remain unknown. This study aimed at assessing whether joint analysis of at-home oximetry and airflow recordings by means of machine-learning algorithms leads to a significant diagnostic performance increase compared to single-channel approaches. Consecutive patients showing moderate-to-high clinical suspicion of OSA were involved. The apnoea-hypopnoea index (AHI) from unsupervised polysomnography was the gold standard. Oximetry and airflow from at-home polysomnography were parameterised by means of 38 time, frequency, and non-linear variables. Complementarity between both signals was exhaustively inspected via automated feature selection. Regression support vector machines were used to estimate the AHI from single-channel and dual-channel approaches. A total of 239 patients successfully completed at-home polysomnography. The optimum joint model reached 0.93 (95%CI 0.90-0.95) intra-class correlation coefficient between estimated and actual AHI. Overall performance of the dual-channel approach (kappa: 0.71; 4-class accuracy: 81.3%) significantly outperformed individual oximetry (kappa: 0.61; 4-class accuracy: 75.0%) and airflow (kappa: 0.42; 4-class accuracy: 61.5%). According to our findings, oximetry alone was able to reach notably high accuracy, particularly to confirm severe cases of the disease. Nevertheless, oximetry and airflow showed high complementarity leading to a remarkable performance increase compared to single-channel approaches. Consequently, their joint analysis via machine learning enables accurate abbreviated screening of OSA at home.

Expectations of nursing degree students: A longitudinal analysis.

BACKGROUND: The expectations of students regarding their studies have a strong influence on their academic performance and personal training, and they are closely related with their academic and professional future. OBJECTIVES: To analyze initial expectations and how they are fulfilled, in a cohort of nursing students during the four years of their degree program. DESIGN: Creation and validation of a questionnaire and longitudinal study. SETTING: University nursing school in Catalonia (Spain). PARTICIPANTS: 339 students of the nursing degree. METHODS: Two questionnaires were constructed with 10 items each, of a mixed nature: some items were previously validated in prior studies while other new items were made and included, following a review of the literature. The questionnaires were designed to assess the expectations of the students at the beginning of the academic year (CUDEX questionnaire) and the fulfillment of these at the end of the year (CUDEX-C questionnaire). RESULTS: Internal consistency (Cronbach's alpha) for the CUDEX questionnaire and the CUDEX-C was 0.70. Factorial analysis of the expectations questionnaires suggested a three-factor model, with an acceptable internal consistency for each of the factors. Statistically significant differences were found between the initial expectations and their fulfillment at the end of the academic year for all the factors and in all four years of the degree program. CONCLUSIONS: The three-factor model of the expectations (Academic adaptation, personal development, and academic performance) shows a good fit for the several samples and time points. The nursing students feel that not all of their expectations were fulfilled during their studies, and there were significant differences between their initial expectations and those fulfilled, in terms of all three factors.

Radioembolization in patients with hepatocellular carcinoma: a series of 53 cases. / Radioembolización de hepatocarcinomas: a propósito de 53 casos.

OBJECTIVE: To contribute our results to increase the scientific evidence about the use of radioembolization in the management of patients with hepatocellular carcinoma. MATERIAL AND METHODS: This retrospective review included 53 patients with hepatocellular carcinoma treated with radioembolization at our center. Patients were classified according to the BCLC algorithm in detail according to their Child-Pugh functional status. We analyzed survival using the Kaplan-Meier method. We used Cox regression analysis to determine clinically significant parameters, including the doses administered in the parameters studied. RESULTS: Patients ranged in age from 28 to 86 years (mean, 60 years). A total of 61 procedures were done. The mean activity administered was 2.8 GBq (0.7-6.4 GBq), with a mean dose of 229.9Gy (74-425.9Gy) administered in the tumor. Progression-free survival was 6.7 months and overall survival was 12.8 months. Differences in disease-free survival according to BCLC and Child-Pugh classification were not significant (p=0.848 and p=0.252, respectively). The clinical parameters that were significantly different with respect to overall survival were bilirubin levels (p<0.001), pretreatment transaminase levels (AST) (p=0.022), Child-Pugh subclassification (p=0.003), and dose administered in the tumor (p=0.001). Only one patient had a severe adverse reaction, developing posttreatment liver failure resulting in death. CONCLUSIONS: Radioembolization is safe and efficacious in the treatment of patients with hepatocellular carcinoma. Liver function and the doses received by the tumor are key parameters for the efficacy of treatment. The increase in the scientific evidence supports the inclusion of this technique in treatment guidelines.

Study of the adrenergic heart innervation with iodine 123-metaiodobenzylguanidine in heart failure before transplantation.

BACKGROUND: The incidence and prevalence of heart failure (HF) are constantly increasing. Heart failure depends on pump failure, inflammatory tracers, and the neurohormonal system. At advanced stages, the only treatment is heart transplantation (HT). We studied myocardial innervation in patients before HT. MATERIALS AND METHODS: The study included 15 patients (11 men and 4 women; age range, 18-69 years) with a diagnosis of New York Heart Association class III-IV or IV HF. Planar thoracic images were obtained, at 15 minutes and 4 hours after injection of 10 mCi of iodine 123-metaiodobenzylguanidine ((123)I-MIBG). Adrenal activity was measured quantitatively using a heart-to-mediastinum count ratio and a myocardial washout rate. Pathologic results were considered if heart-to-mediastinum count ratio was less than 1.8 and washout rate was more than 35%. RESULTS: The qualitative analysis revealed decreased (123)I-MIBG myocardial uptake in all patients. Using the quantitative scale, patients were classified into four groups, as follows: group 1, physiologic innervation, no patients; group 2, mild myocardial adrenergic involvement, one patient (6.7%); group 3, moderate myocardial adrenergic involvement, five patients (33.3%); and group 4, severe myocardial adrenergic involvement, 9 patients (60%). The washout rate was pathologic in 11 of the 15 patients (73.3%). CONCLUSIONS: Scintigraphy using (123)I-MIBG is a useful method to evaluate prognosis in patients with advanced HF and can be used to assess transplantation priorities. It will be necessary to study a larger number of patients to confirm these findings.

Arsenic removal from waters by bioremediation with the aquatic plants Water Hyacinth (Eichhornia crassipes) and Lesser Duckweed (Lemna minor).

In this study the removal of arsenic by the Water Hyacinth (Eichhornia crassipes) and Lesser Duckweed (Lemna minor) was monitored under a concentration of 0.15mgL(-1) of the element. Plant densities were 1kg/m2 for Lesser Duckweed and 4kg/m2 for Water Hyacinth on a wet basis. The arsenic was determined in foliar tissue and water samples by hydride generation atomic absorption spectroscopy. The element was monitored as a function of time during 21 days. No significant differences were found in the bioaccumulation capability of both species. The removal rate for L. minor was 140mg As/had with a removal recovery of 5%. The Water Hyacinth had a removal rate of 600mg As/had and a removal recovery of 18%, under the conditions of the assay. The removal efficiency of Water Hyacinth was higher due to the biomass production and the more favorable climatic conditions. This specie represents a reliable alternative for arsenic bioremediation in waters.

An assessment of the application of ultrasound in the processing of ready-to-eat whole brown crab (Cancer pagurus).

This study assesses the potential of incorporating ultrasound as a processing aid in the production of whole cooked brown crab (Cancer pagurus). The FDA recommended heat treatment to reduce Listeria monocytogenes by 6 log10 cycles in this product is a F707.5 of 2min. An equivalent F value was applied at 75°C in presence and absence of ultrasound in water alone or in water with 5% w/v NaCl added. Heat penetration, turbidity and conductivity of the cook water and also salt and moisture content of the crab meat (white and brown) were determined. Ultrasound assisted cooking allowed a reduction of the cooking time by up to 15% while still maintaining an F707.5 of 2min. Ultrasound also enhanced the rate and total amount of compounds released from the crab, which suggests that crabs cooked in the presence of ultrasound would be expected to be cleaner. Ultrasound also proved to be effective in reducing the salt content but hardly affected the final moisture content of the crab meat.

Evaluation of the potential of ultrasound technology combined with mild temperatures to reduce cadmium content of edible crab (Cancer pagurus).

The consumption of crustaceans is correlated with certain health risks, particularly due to several highly toxic elements they contain, including cadmium (Cd). Although Cd content in one sole crab generally exceeds the total weekly recommended intake of cadmium as established by EFSA (especially in brown meat), efficient modern strategies to reduce Cd content in crabs still have not yet been developed. The objective of this research was therefore to evaluate the potential use of ultrasound technology in combination with temperature (50°-80 °C) with the purpose of releasing Cd from brown crab (Cancer pagurus), thereby reducing the Cd content in its meat. Female crabs were immersed in a water bath at 50, 65, and 80 °C in presence or absence of ultrasound; Cd concentration in the water was monitored along time. At the end of the process, Cd content in brown and white crab meat was likewise quantified. Treatment temperature did not bear an influence on the release of Cd in absence of ultrasound, but proved to be an important variable when ultrasound assisted the process. Ultrasound increased Cd release rates 8.7-, 2.1- and 2.7-fold in conjunction with the treatments at 50, 65 and 80 °C, respectively. The maximum percentage of Cd extracted (22.8%) was observed at 50 °C for an ultrasound input power of 200 W. These results have demonstrated for the first time that the application of ultrasound during the crab-cooking process could serve as an effective physical procedure for reducing the Cd content of crabs, thereby improving the product's safety for consumers.

Ophthalmic administration of a 10-fold-lower dose of conventional nanoliposome formulations caused levels of intraocular pressure similar to those induced by marketed eye drops.

The purpose of this study was to compare the in vivo efficacy of several timolol (TM)-loaded liposomal formulations with current TM antiglaucoma treatment (aqueous 0.5% w/v eye drops). In this study, conventional liposomes (CL) and deformable liposomes, without (DL1) and with ethanol (DL2) were prepared and characterized. In addition, in vitro release and permeation studies, as well as in vivo lowering intraocular pressure (IOP) and biocompatibility studies were performed. It was found that the quali and quantitative lipid bilayer composition played a significant role in modifying the physical properties of vesicles. The deformability study and electronic microscopy images revealed that membrane elasticity of DL1 and DL2 was much higher than CL. However, in vitro permeation results showed that the flux and permeability coefficient were significantly higher in CL compared to DL. The IOP study revealed that TM-loaded CL showed the best pharmacological activity, in comparison to deformable vesicles. Compared to the eye drops, CL formulation could equally reduce the IOP but using a concentration 10-fold lower, whereas the effective time was significantly longer. In addition, the formulations showed no irritant effects after instillation on the ocular surface.

Microhardness of starch based biomaterials in simulated physiological conditions.

In this work the variation of the surface mechanical properties of starch-based biomaterials with immersion time was followed using microhardness measurements. Two blends with very distinct water uptake capabilities, starch/cellulose acetate (SCA) and starch/poly(epsilon-caprolactone) (SPCL), were immersed in a phosphate buffer solution (PBS) at 37.5 degrees C for various times. The microhardness of the blends decreased significantly ( approximately 50% for SPCL and approximately 94% for SCA), within a time period of 30 days of immersion, reflecting the different hydrophilic character of the synthetic components of the blends. The dependence of microhardness on the applied loading time and load was also analysed and showed a power law dependency for SCA. Water uptake and weight loss measurements were performed for the same immersion times used in the microhardness experiments. The different swelling/degradation behaviour presented by the blends was related to the respective variation in microhardness. Moreover, complementary characterization of the mechanical properties of SCA and SPCL was accomplished by dynamic mechanical analysis (DMA) and creep measurements. Microhardness measurements proved to be a useful technique for characterizing the mechanical behaviour near the surface of polymeric biomaterials, including in simulated physiological conditions.

Assessment of automated analysis of portable oximetry as a screening test for moderate-to-severe sleep apnea in patients with chronic obstructive pulmonary disease.

BACKGROUND: The coexistence of obstructive sleep apnea syndrome (OSAS) and chronic obstructive pulmonary disease (COPD) leads to increased morbidity and mortality. The development of home-based screening tests is essential to expedite diagnosis. Nevertheless, there is still very limited evidence on the effectiveness of portable monitoring to diagnose OSAS in patients with pulmonary comorbidities. OBJECTIVE: To assess the influence of suffering from COPD in the performance of an oximetry-based screening test for moderate-to-severe OSAS, both in the hospital and at home. METHODS: A total of 407 patients showing moderate-to-high clinical suspicion of OSAS were involved in the study. All subjects underwent (i) supervised portable oximetry simultaneously to in-hospital polysomnography (PSG) and (ii) unsupervised portable oximetry at home. A regression-based multilayer perceptron (MLP) artificial neural network (ANN) was trained to estimate the apnea-hypopnea index (AHI) from portable oximetry recordings. Two independent validation datasets were analyzed: COPD versus non-COPD. RESULTS: The portable oximetry-based MLP ANN reached similar intra-class correlation coefficient (ICC) values between the estimated AHI and the actual AHI for the non-COPD and the COPD groups either in the hospital (non-COPD: 0.937, 0.909-0.956 CI95%; COPD: 0.936, 0.899-0.960 CI95%) and at home (non-COPD: 0.731, 0.631-0.808 CI95%; COPD: 0.788, 0.678-0.864 CI95%). Regarding the area under the receiver operating characteristics curve (AUC), no statistically significant differences (p >0.01) between COPD and non-COPD groups were found in both settings, particularly for severe OSAS (AHI ≥30 events/h): 0.97 (0.92-0.99 CI95%) non-COPD vs. 0.98 (0.92-1.0 CI95%) COPD in the hospital, and 0.87 (0.79-0.92 CI95%) non-COPD vs. 0.86 (0.75-0.93 CI95%) COPD at home. CONCLUSION: The agreement and the diagnostic performance of the estimated AHI from automated analysis of portable oximetry were similar regardless of the presence of COPD both in-lab and at-home. Particularly, portable oximetry could be used as an abbreviated screening test for moderate-to-severe OSAS in patients with COPD.