DISTRIBUTED-DELAY MODELS OF THE GLUCOSE-INSULIN HOMEOSTASIS AND ASYMPTOTIC STATE OBSERVATION

Abstract In this paper the problem of the real-time reconstruction of plasma insulin concentration by using only blood glucose measurements is investigated. This is an interesting problem because the knowledge of the time course of the glucose and insulin concentrations in an individual provides precious informations concerning its health state, and may assume the role of a clinical instrument. For the purpose of the reconstruction of the insulinemia a dynamical model of the glucose-insuline homeostasis is required. The present work considers distributed delay models. Such models have been preferred in recent papers with respect to the standard Minimal Models, available in literature from 70's, because they allow to couple the glucose and insulin dynamics in a unique extended system, whose solutions have been proven to be positive, bounded, and globally asymptotically stable around the basal values of the equilibrium point. Data are acquired according to the Intra Venous Glucose Tolerance Test (IVGTT). Simulation results are reported in order to validate the developed theory

A microcapillary rheometer for microliter sized polymer characterization

Abstract We report the design of a microcapillary rheometer (μCR) that allows to perform experiments rapidly and in a broad range of shear rates (i.e., from 0.1 to 1000 s−1), using small amounts of material (i.e., just few milligrams). Additionally, multiple measurement parallelization makes it suitable for High-Throughput Rheological Experimentation of polymer melts (HT-Rheo-E). The novel rheometer consists of a set of three cylindrical microcapillaries in which the fluid flows driven by a controlled pressure. A camera, placed at the capillary exit, records the fluid motion to measure its flow rate, from which the fluid viscosity can be determined. The optimization of the setup allowed for reliable and fast viscosity measurements using ca. 10 mg of material. The current work reports the design of the rheometer and validation measurements on several model fluids. The microfabricated μCR is of potential interest for applications in quality control and research where rapid and repeated measurements using limited milligrams of polymer are required, as well as for High-Throughput-Experimentation of complex fluids (e.g., biological systems)

Prevention of postoperative atrial fibrillation in open heart surgery patients by preoperative supplementation of n-3 polyunsaturated fatty acids: An updated meta-analysis

BackgroundSeveral randomized clinical trials evaluated whether preoperative supplementation of omega-3 (n-3) polyunsaturated fatty acids protects against postoperative atrial fibrillation after cardiac surgery, a condition associated with increased cardiac and cerebral mortality. However, their efficacy remains still controversial. An updated meta-analysis was performed to clarify if preoperative n-3 polyunsaturated fatty acid supplementation prevents postoperative atrial fibrillation in patients undergoing cardiac surgery.MethodsArticles were retrieved until November 2012 by screening electronic databases (PubMed, EMBASE, Web of Science, and Cochrane Central Register of Controlled Trials) and cross references. Two of us independently reviewed articles and agreed to select 8 randomized clinical trials. For each study, the incidence of atrial fibrillation in both the intervention and placebo groups was extracted to calculate odd ratio and 95% confidence intervals (CIs). Weighted study-specific estimates were combined using fixed (Mantel-Haenszel method) and random-effects (DerSimonian-Laird method) models.ResultsThis meta-analysis includes 2687 patients (1337 in the intervention group) who underwent cardiac surgery. Pooled analysis using fixed-effects models showed a significant reduction (average, 16%; 95% CI, 1%-29%) in postoperative atrial fibrillation by preoperative n-3 polyunsaturated fatty acids. There was a low heterogeneity among studies (P = .07 and I2 = 46%). By using a random-effects model, the reduction averaged 25% (odds ratio, 0.75; 95% CI, 0.57-1.00; P = .05). When isolated coronary artery bypass graft surgery was only considered (7 studies), a significant protection averaging 34% was observed in a fixed model (odds ratio, 0.66; 95% CI, 0.50-0.87; P = .003; I2 = 26%, P = .23).ConclusionsA preoperative supplementation of n-3 polyunsaturated fatty acids significantly prevents the occurrence of postoperative atrial fibrillation in patients undergoing cardiac surgery, in particular coronary artery bypass surgery

Mathematical Models and State Observation of the Glucose-Insulin Homeostasis

n/

Ultra-processed food consumption and its correlates among Italian children, adolescents and adults from the Italian Nutrition & Health Survey (INHES) cohort study

Objective: To assess ultra-processed food (UPF) consumption and its socio-demographic, psychosocial and behavioural correlates in a general population of Italian children, adolescents and adults. Design: Cross-sectional telephone-based survey Setting: Italy, 2010-2013. Participants: In total, 9078 participants (5-97 years) from the Italian Nutrition & Health Survey. Dietary intakes were collected by a 1-d 24-h dietary recall. UPF was defined by the NOVA classification and expressed as percentage of total energies. Results: Average energy intake from UPF (95 % CI) was 17·3 % (17·1 %, 17·6 %) among adults and 25·9 % (24·8 %, 27·0 %) in children/adolescents. Top sources of UPF were processed meats (32·5 %) and bread substitutes (16·7 %). Among adults, age (β = -3·10; 95 % CI (-4·40, -1·80) for >65 years v. 20-40 years; βs are dimensionless) and residing in Southern Italy (β = -0·73; 95 % CI (-1·32, -0·14) v. Northern) inversely associated with UPF. Screen view during meals was directly linked to UPF, as well as poor self-rated health (β = 5·32; 95 % CI (2·66, 7·99)), adverse life events (β = 2·33; 95 % CI (1·48, 3·18)) and low sleep quality (β = 2·34; 95 % CI (1·45, 3·23)). Boys consumed two-point percent more UPF of the total energy than girls (β = 2·01; 95 % CI (0·20, 3·82)). For all ages, a Mediterranean diet was inversely associated with UPF (β = -4·86; 95 % CI (-5·53, -4·20) for good v. poor adherence in adults and (β = -5·08; 95 % CI (-8·38, -1·77) for kids). Conclusions: UPF contributes a modest proportion of energy to the diets of Italian adults while being one-quarter of the total energies in children/adolescents. UPF was associated with several psychosocial factors and eating behaviours. Increased adherence to Mediterranean diet would possibly result in lower UPF consumption

Serum amino acid profiles in normal subjects and in patients with or at risk of Alzheimer dementia

Background/Aims: Abnormalities in the plasma amino acid profile have been reported in Alzheimer disease (AD), but no data exist for the prodromal phase characterized by subjective memory complaint (SMC). It was our aim to understand if serum amino acid levels change along the continuum from normal to AD, and to identify possible diagnostic biomarkers. Methods: Serum levels of 15 amino acids and 2 organic acids were determined in 4 groups of participants – 29 with probable AD, 18 with mild cognitive impairment (MCI), 24 with SMC, and 46 cognitively healthy subjects (HS) – by electrospray tandem mass spectrometry. Results: Glutamate, aspartate, and phenylalanine progressively decreased, while citrulline, argi­ninosuccinate, and homocitrulline progressively increased, from HS over SMC and MCI to AD. The panel including these 6 amino acids and 4 ratios (glutamate/citrulline, citrulline/phenylalanine, leucine plus isoleucine/phenylalanine, and arginine/phenylalanine) discriminated AD from HS with about 96% accuracy. Other panels including 20 biomarkers discriminated SMC or MCI from AD or HS with an accuracy ranging from 88 to 75%. Conclusion: Amino acids contribute to a characteristic metabotype during the progression of AD along the continuum from health to frank dementia, and their monitoring in elderly individuals might help to detect at-risk subjects

Ultra-processed food consumption and its correlates among Italian children, adolescents and adults from the Italian Nutrition & Health Survey (INHES) cohort study.

AbstractObjective:To assess ultra-processed food (UPF) consumption and its socio-demographic, psychosocial and behavioural correlates in a general population of Italian children, adolescents and adults.Design:Cross-sectional telephone-based surveySetting:Italy, 2010–2013.Participants:In total, 9078 participants (5–97 years) from the Italian Nutrition & Health Survey. Dietary intakes were collected by a 1-d 24-h dietary recall. UPF was defined by the NOVA classification and expressed as percentage of total energies.Results:Average energy intake from UPF (95 % CI) was 17·3 % (17·1 %, 17·6 %) among adults and 25·9 % (24·8 %, 27·0 %) in children/adolescents. Top sources of UPF were processed meats (32·5 %) and bread substitutes (16·7 %). Among adults, age (β = −3·10; 95 % CI (−4·40, −1·80) for >65 years v. 20–40 years; βs are dimensionless) and residing in Southern Italy (β = −0·73; 95 % CI (−1·32, −0·14) v. Northern) inversely associated with UPF. Screen view during meals was directly linked to UPF, as well as poor self-rated health (β = 5·32; 95 % CI (2·66, 7·99)), adverse life events (β = 2·33; 95 % CI (1·48, 3·18)) and low sleep quality (β = 2·34; 95 % CI (1·45, 3·23)). Boys consumed two-point percent more UPF of the total energy than girls (β = 2·01; 95 % CI (0·20, 3·82)). For all ages, a Mediterranean diet was inversely associated with UPF (β = −4·86; 95 % CI (−5·53, −4·20) for good v. poor adherence in adults and (β = −5·08; 95 % CI (−8·38, −1·77) for kids).Conclusions:UPF contributes a modest proportion of energy to the diets of Italian adults while being one-quarter of the total energies in children/adolescents. UPF was associated with several psychosocial factors and eating behaviours. Increased adherence to Mediterranean diet would possibly result in lower UPF consumption

Distribution pattern of hepatitis C virus genotypes and correlation with viral load and risk factors in chronic positive patients.

Objective: Hepatitis C virus (HCV) has emerged as a leading cause of chronic hepatitis, liver cirrhosis and hepatocellular carcinoma worldwide. The purpose of this study was to describe the distribution pattern of HCV genotypes in chronic hepatitis patients in the Campania region of southern Italy and estimate their association with risk factors and viral load. Materials and Methods: 404 consecutive HCV ribonucleic acid-positive patients were included in the study. HCV genotyping was carried out by the HCV line probe assay test and viral load estimation by the TaqMan real-time PCR system. Results: The predominant genotype was 1 (63.6%), followed by genotype 2 (29.4%), 3 (6.2%) and 4 (0.8%). Subtype 1b was more frequent in females than in males. Conversely, genotype 3 was more frequent in males. No significant difference was observed in age distribution of HCV genotypes. Surgery and dental therapy were the most frequent risk factors for genotype 1 and intravenous drug abuse and tattooing for genotype 3. Patients with genotype 1 more frequently showed high HCV viral load when compared to those with genotypes 2 and 3. Conclusion: The present study revealed that HCV genotypes 1 and 2 accounted for over 95% of all HCV infections in the Campania region, and genotype 1 was more frequently associated with a higher viral load when compared to genotypes 2 and 3

Role of leukocytes, gender, and symptom domains in the influence of depression on hospitalization and mortality risk: Findings from the Moli-sani study

Background: Major depressive disorder is a mental illness associated with chronic conditions like cardiovascular disease (CVD). Circulating inflammation has been proposed as a potential mechanism underlying this link, although the role of specific biomarkers, gender, and symptom domains is not well elucidated. Methods: We performed multivariable Cox regressions of first hospitalization/all-cause mortality and CVD, ischemic heart (IHD), and cerebrovascular disease (CeVD) causes vs. depression severity in an Italian population cohort (N = 13,191; age ≥ 35 years; 49.3% men; 4,856 hospitalizations and 471 deaths, median follow-up 7.28 and 8.24 years, respectively). In models adjusted for age, sex, and socioeconomic status, we estimated the proportion of association explained by C-reactive protein (CRP), platelet count, granulocyte-to-lymphocyte ratio (GLR), and white blood cell count (WBC). Gender-by-depression interaction and gender-stratified analyses were performed. Associations of polychoric factors tagging somatic and cognitive symptoms with incident clinical risks were also tested, as well as the proportion explained by a composite index of circulating inflammation (INFLA score). Results: Significant proportions of the influence of depression on clinical risks were explained by CRP (4.8% on IHD hospitalizations), GLR (11% on all-cause mortality), and WBC (24% on IHD/CeVD hospitalizations). Gender-by-depression interaction was significantly associated only with all-cause mortality (p = 0.03), with moderate depression showing a + 60% increased risk in women, but not in men. Stable associations of somatic, but not of cognitive, symptoms with increased hospitalization risk were observed (+ 16% for all causes, + 14% for CVD causes), with INFLA score explaining small but significant proportions of these associations (2.5% for all causes, 8.6% for IHD causes). Conclusions: These findings highlight the importance of cellular components of inflammation, gender, and somatic depressive symptoms in the link between depression and clinical (especially CVD) risks, pointing to the existence of additional pathways through which depression may play a detrimental effect on the cardiovascular system

Fibrinogen levels in relation to colorectal cancer onset: A nested case-cohort study from the Moli-sani cohort

Background: Patients with cancer are commonly characterized by abnormalities in laboratory coagulation tests, underlying a subclinical hypercoagulable condition. Due to the involvement of the hemostatic system in cancer patients, some of its biomarkers, such as fibrinogen, could be a useful tool in predicting cancer risk. We performed a case-cohort study to evaluate the relationship among fibrinogen levels and colorectal cancer (CRC). Methods: In the framework of Moli-sani Study (N = 24,325, enrolled 2005–2010) a subcohort of 1,290 individuals (55.0% women; mean age 55.0 ± 12.0 years) was selected and compared with 126 CRC cases identified during a follow-up of 4.3 years. Incident cases of colorectal cancer were ascertained by direct linkage with hospital discharge forms according to the International Classification of Disease (ICD-9-CM) codes: 153–154. Events were validated through medical records and confirmed by histological reports. Fibrinogen levels were measured in frozen citrated plasma samples. Hazard Ratio (HR) and 95% confidence interval (CI), adjusted by relevant covariates were estimated by a Cox regression model using Prentice method. Results: Individuals with levels of fibrinogen ≥400 mg/dL had a higher hazard to develop colorectal cancer when compared to those with lower levels after adjustment for sex and age (HR: 1.81; 95% CI 1.12–2.92). Additional adjustment for CRC family history, income, physical activity, diabetes medication and hypercholesterolemia did not modify the result (HR: 1.91; 95% CI 1.15–3.17). Analyses stratified by age and sex showed a most evident association in elderly (HR: 2.30; 95% CI: 1.10–4.81) and in women (HR: 2.28; 95% CI: 1.08–4.81). Sensitivity analyses confirmed the main findings, showing independence from a potential role of confounding by a large panel of biomarkers, including inflammation and hemostasis factors. Conclusion: Our results, based on a case-cohort study from a general adult population apparently free from any cancer during the recruitment, showed that fibrinogen levels ≥400 mg/dL were positively and independently associated with CRC, suggesting that this glycoprotein could be a potential biomarker for this type of cancer and supporting the “common soil hypothesis” in the pathophysiology of cardiovascular disease and tumors