Association of salt sensitivity and insulin resistance in normotensing offspring of hypertensive parents

The concept of sodium sensitivity originated in population surveys in various parts of the world, demostrated that the prevalence of hypertension rises with habitual dietary sodium intake. As for the normotensive, the incidence of hypertension is higher in the sodium-sensitive subjects. Hypertension is unknown in those societies in which no sodium is added to the diet. The sodium sensitivity is present in some individuals and totally absent in others and is genetically linked. Several lines of evidence indicate that salt-sensitive normotensive indivituals are genetically prone to the development of hypertension. Also normotensive individuals with a family history of high blood pressure are insulin resistant and hyperinsulinemic when compared to a matched group of healthy volunteers without a family history of hypertension It has been postulated that insulin resistance and the concominant compesatory hyperinsulinemia contribute to the pathogenesis of hypertension possibly by stimulating the sympathetic nervous system, promoting renal sodium reabsorption, modulating cation transport and/or stimulating vascular smooth muscle hypertrophy. It remains unclear whether the hyperinsulinemia described in association with essential hypertension is an epiphenomenon, a consequence of hypertension or a causal factor in the rise of blood pressure. The purpose of this study was to investigate the possible correlation between salt sensitivity and insulin resistance in hypertension prone man. We studied 30 normotensive subjects, 20 with familial history of hypertension (group A) and 10 without (group B). In both groups it was estimated: 1. The presence or not of sodium sensitivity (NS) in descendants of hypertensive (group A) or normotensive parents (group B) 2. Insulin resistance (IR), using the euglycemic insulin clamp technique. An effort has been made to correlate NS to IR and hyperinsulinaemia in offspring of hypertensive parents (group A) as well as between the two groups (A and B). The correlation between NS and IR with biochemical values was also tested. The following results were obtained: 1. There was no difference in regard to NS between the 2 groups. 2. Individuals with hypertensive parents (group A) had a greater predisposition to develop IR (45%) compared to 20% of the control group. 3. No significant statistical correlation was found between NS and IR in both the entire examined population, as well as in those with or without a history of hypertension. 4. No significant statistical difference was noted in mean values of biochemical indices between individuals who were Na-sensitive in group A and B, with the unique exception of total cholesterol, where individuals of group A had greater mean values compared to individuals comprising group B. 5. It was observed greater values of total cholesterol in individuals with hypertensive parents (group A). 6. It was observed a trend increased IR with increase mean arterial pressure (MAP). Although no correlation was found between NS and IR in offsprings of hypertensive parents, the increased prevalence of those parameters in group A may advocate not only their coexistence but also their essential contribution in the pathogenesis of essential hypertension.Τα τελευταία χρόνια περιγράφεται το μεταβολικό σύνδρομο που χαρακτηρίζεται από ειδικό τύπο παχυσαρκίας, αντίσταση στην ινσουλίνη, υπέρταση και διαταραχές του μεταβολισμού των λιπιδίων. Υπάρχει πλήθος μελετών που ερευνά εάν υπάρχει κοινός παθογενετικός μηχανισμός με απώτερο σκοπό την πρόληψη του συνδρόμου και των καρδιαγγειακών επιπλοκών. Η αυξημένη πρόσληψη άλατος έχει ενοχοποιειθεί για την αύξηση της αρτηριακής πίεσης. Όλα τα άτομα όμως δεν εμφανίζουν την ίδια μεταβολή της αρτηριακής πίεσης με την πρόσληψη άλατος (νατριοευαισθησία) η οποία φαίνεται να επηρεάζεται από γενετικούς παράγοντες και την ηλικία. Υπάρχουν στοιχεία που δείχνουν ότι νορμοτασικά νατριοευαίσθητα άτομα είναι γενετικά προδιατεθειμένα να αναπτύξουν υπέρταση. Για την αρτηριακή υπέρταση πιθανόν ευθύνεται και η υπερινσουλιναιμία η οποία είναι αποτέλεσμα της αυξημένης αντίστασης στην ινσουλίνη. Οι πιθανοί μηχανισμοί με τους οποίους η υπερινσουλιναιμία προκαλεί υπέρταση φαίνεται να είναι:1) ο αυξημένος τόνος του συμπαθητικού συστήματος, 2) η αυξημένη επαναρρόφηση Να κυρίως στο εγγύς εσπειραμένο σωληνάριο, 3) η διαταραχή των ηλεκτρολυτών σε κυτταρικό επίπεδο και συγκεκριμένα η κατακράτηση Να ενδοκυττάρια με αποτέλεσμα την αύξηση της ευαισθησίας των λείων μυϊκών ινών στις κατεχολαμίνες και 4) η πάχυνση του τοιχώματος των αγγείων η οποία πιθανόν προκαλείται από την ινσουλίνη που δρα σαν αυξητικός παράγοντας. Φαίνεται από σειρά μελετών ότι νορμοτασικά άτομα με οικογενειακό ιστορικό υπέρτασης παρουσιάζουν σε μεγαλύτερο ποσοστό αντίσταση στην ινσουλίνη-υπερινσουλιναιμία σε σχέση με άτομα χωρίς ιστορικό υπέρτασης. Ως γνωστόν στα αίτια της αυξημένης αντίστασης στην ινσουλίνη αναφέρονται και γενετικοί παράγοντες, η δε υπέρταση εμφανίζεται συχνότερα στους απογόνους ατόμων με υπέρταση. Στη διεθνή βιβλιογραφία υπάρχει διχογνωμία εάν η υπερινσουλιναιμία που συνοδεύει την υπέρταση είναι επιφαινόμενο ή ο αιτιολογικός παράγοντας εμφάνισης της υπέρτασης. Επίσης δε φαίνεται να έχει προσδιορισθεί η σχέση νατριοευαισθησίας και αντίστασης στην ινσουλίνη οι οποίες ενδέχεται να είναι στοιχεία ενιαίου παθογενετικού μηχανισμού. Σκοπός της παρούσας μελέτης ήταν να δείξει εάν υπάρχει συσχέτιση μεταξύ της νατριοευαισθησίας και αντίστασης στην ινσουλίνη σε άτομα με οικογενή προδιάθεση εμφάνισης αρτηριακής υπέρτασης. Σκοπός της παρούσας μελέτης ήταν να δείξει εάν υπάρχει συσχέτιση μεταξύ της νατριοευαισθησίας και αντίστασης στην ινσουλίνη σε άτομα με οικογενή προδιάθεση εμφάνισης αρτηριακής υπέρτασης

High-resolution speech signal reconstruction in wireless sensor networks

Abstract—Data streaming is an emerging class of applications for sensor networks that has very high bandwidth and processing power requirements. In this paper, a new approach for speech data streaming is proposed, which is based on a distributed scheme. This scheme focuses on balancing the energy consumption among nodes in a sensor network by allowing lowresolution streams from multiple nodes to be fused at a central processing node in order to produce an enhanced resolution speech signal. Simulations and experimental results with real microphone signals are presented. I

DistressNet: A wireless ad hoc and sensor network architecture for situation management in disaster response

Situational awareness in a disaster is critical to effective response. Disaster responders require timely delivery of high volumes of accurate data to make correct decisions. To meet these needs, we present DistressNet, an ad hoc wireless architecture that supports disaster response with distributed collaborative sensing, topology-aware routing using a multichannel protocol, and accurate resource localization. Sensing suites use collaborative and distributed mechanisms to optimize data collection and minimize total energy use. Message delivery is aided by novel topology management, while congestion is minimized through the use of mediated multichannel radio protocols. Estimation techniques improve localization accuracy in difficult environments. © 2010 IEEE

High level of recovery of fungi from water and dialysate in haemodialysis units

The counts of yeasts and filamentous fungi were investigated in the municipal water supplies of haemodialysis centres, in the treated water and the dialysate from all 85 haemodialysis units in Greece, in order to estimate their occurrence, their correlation with contamination indicator bacteria and other influencing factors. Filamentous fungi and yeasts were isolated from 69 (81.2%) and from three (3.5%) feed it;ater samples, from 74 (87.1%) and seven (8.2%) treated water samples and from 66 (77.7%) and 11 (12.9%) dialysate samples respectively Aspergillus spp and Penicillium spp were the most frequent moulds, while Candida spp were the prevailing yeasts. The occurrence of yeasts was significantly higher in dialysate than in tap water samples. Counts of filamentous fungi in all 255 samples were significantly correlated with the counts of total heterotrophic bacteria and enterococci, whereas the counts of yeasts were correlated with faecal coliforms, total heterotrophic bacteria, as well as enterococci, Pseudomonas spp and total coliforms, while no correlation was detected with the age of either heamodialysis units, the age of water treatment system, the number of artificial kidney machines or the components of the water purification sq stem. High recovery of fungi from haemodialysis aqueous environments implies a potential risk for haemodialysis patients and indicates the need for continuous maintenance and monitoring. (C) 2000 The Hospital Infection Society