No description available.

The main objective of this thesis is to contribute to the prevention and control of the cardiovascular risk, hydration state and nutritional state in dialysis patients using non-invasive electrical impedance measurements. The thesis is structured in three parts with the following objectives: 1) to establish electrical impedance reference data for healthy Cuban population, 2)to improve the diagnostic based on impedance methods in Cuban hemodialysis (HD)patients and 3) to develop the impedance methods for continuous ambulatory peritoneal dialysis patients (CAPD).Healthy population: We analyzed the impedance vector distribution using the Bioimpedance Vector Analysis (BIVA) for the three more representative race-ethnicities in Cuba. We measured 1196 healthy adult (689 M, 507 W, 18-70 yr). The 95% confidence ellipses were drawn using specific BIVA software for mean vectors of different races. Due to the close distribution of mean vectors that we found for the three race-ethnicities, we concluded that only one set of sex-specific tolerance ellipses can be used for the Cuban population.HD patients: The BIVA method was used in a sample of 74 HD patients in stable (without edema) and critical (hyper-hydrated and malnutrition) states in order to establish the relation between hyper-hydration and mortality. Stable group include 48 patients (28 M and 18 W), and critical group include 28 critical patients (16 M and 12 W). Student's t test and Hotelling's T2 test were used to analyse the separation of groups obtained by means of clinical diagnosis and those obtained by BIVA. A statistically significant difference was obtained (P < 0.05) in R/H, Xc/H and phase angle, PA. Critical patients (hyper-hydrated and malnutrition) were located below the inferior pole of the 75% tolerance ellipse, with PA lower than 4º. In conclusion, the BIVA method could be used to detect hyper-hydration state before edema appears, and to predict survival through PA. Advantages of the method are its simplicity, objectivity and that it does not require the definition of a patient dry weight.CAPD patients: Segmental impedance measurements were obtained using 9 configurations (7 longitudinal and 2 transversal) in 25 CAPD male patients.In a first study we analyzed Z, Z/H and ZBMI indexes. 23 male patients were classified according to the hydration state as normo-hydrated, group 0 (10 M) or hyper-hydrated, group 1 (13 M). Wilcoxon test was used to analyze the change in impedance produced by a PD session. Mann-Whitney U test was used to analyse the separation between groups obtained by means of clinical diagnosis and those obtained by Z, Z/H or ZBMI. Spearman correlation was used to study the correlation between impedance vectors in each segment and clinical assessment. Statistical significance was set at P < 0.05. Results show that ZBMI gives information about the specific resistivity of tissues and not about fluid and fat mass changes. BIVA separate hyper-hydrated and normo-hydrated patients. Transversal measurements in the leg region and longitudinal in the thorax region are useful to corroborate the hydration and nutritional state in CAPD patients.In a second study a new classification was performed. Group 0 has normo-hydrated patients (10 M) and group 1 includes patients (15 M) with varying degrees of hypertension, overhydration and high score on cardiovascular risk factors. Mann-Whitney U-test was used to compare the differences in clinical measurements, laboratory test, and bioimpedance measurements between groups. The Mahalanobis Distance (dM2) was calculated using a bidimensional space, using the resistance measurement, right-side (RRS/H) or thorax segment (RTH/H) and the BPmean. Hotelling's T2 test was used to analyzed difference between groups through (RTH/H, BPmean) and (RRS/H, BPmean) vectors. A statistically significant difference was obtained (P < 0.05) in both vectors. Group 1 showed a small dM2 with respect to a reference patient (a critical patient with acute lung oedema) with high BPmean and low values of RTH/H and RRS/H. Moreover, Group 0 showed a larger dM2 with respect to the reference patient with lower BPmean and higher values of RTH/H and RRS/H. All patients classified as hyper-hydrated leading to hypertension by clinical assessment were correctly classified using dM2(RTH/H, BPmean). We conclude that segmental bioimpedance of the thoracic region could be a simple, objective, non-invasive method of support to facilitate the clinical assessment in CAPD.

Η μακροπρόθεσμη έκθεση της περιτοναϊκής μεμβράνης σε μη βιοσυμβατά περιτοναϊκά διαλύματα οδηγεί σε δομικές αλλαγές και στην απώλεια της υπερδιήθησης. Σκοπός της παρούσας μελέτης είναι να περιγράψουμε τις ιστολογικές αλλαγές της περιτοναϊκής μεμβράνης που παρατηρούνται: α) σε ουραιμικούς ασθενείς που ξεκινούν θεραπεία υποκατάστασης της νεφρικής λειτουργίας με περιτοναϊκή κάθαρση και β) σε ασθενείς που ήδη υποβάλλονται στη μέθοδο για ικανό χρονικό διάστημα. Επίσης να καθορίσουμε κατά πόσο οι μορφολογικές αυτές αλλαγές επηρεάζουν τα λειτουργικά χαρακτηριστικά του περιτοναίου. Μέθοδος: Στη μελέτη περιλήφθηκαν 19 ασθενείς (ομάδα Α) οι οποίοι υποβλήθηκαν σε βιοψία περιτοναίου κατά την τοποθέτηση του περιτοναϊκού καθετήρα και πριν την έναρξη της περιτοναϊκής κάθαρσης (CAPD) και 18 ασθενείς οι οποίοι υποβλήθηκαν σε βιοψία περιτοναίου μετά από 4 χρόνια σε CAPD (ομάδα Β). Οι ιστολογικές παράμετροι που ελέχθησαν ήταν η μεσοθηλιακή επιφάνεια, η υπομεσοθηλιακή ζώνη, η κατάσταση του συνδετικού ιστού και η κατάσταση των αγγείων. Για την εκτίμηση των λειτουργικών χαρακτηριστικών του περιτοναίου και της επάρκειας της μεθόδου εφαρμόσθηκαν η δοκιμασία εξισορρόπησης της περιτοναϊκής μεμβράνης (PET), η συνολική εβδομαδιαία κάθαρση κρεατινίνης (wClcr) και το συνολικό εβδομαδιαίο KT/V της ουρίας (wKT/V). Αποτελέσματα: Οι κύριες ιστολογικές αλλαγές και στις δύο ομάδες ασθενών ήταν η απώλεια των μεσοθηλιακών κυττάρων, η πάχυνση της υπομεσοθηλιακής ζώνης και η υαλίνωση των αγγείων. Το πάχος της υπομεσοθηλιακής ζώνης και στις δύο ομάδες ασθενών ήταν σημαντικά υψηλότερο έναντι φυσιολογικών μαρτύρων (630μm και 1140μm vs. 50μm αντίστοιχα, p <0.05). Αν και δε βρέθηκε σημαντική διαφορά μεταξύ των μορφολογικών αλλαγών του περιτοναίου στους ασθενείς της ομάδας Α και στους ασθενείς της ομάδας Β, υπήρξε μια τάση για σοβαρότερου βαθμού βλάβες στους τελευταίους. Το PET, η wClcr και το wKT/V δεν παρουσίασαν στατιστικά σημαντικές διαφορές στις δύο ομάδες ασθενών, ούτε στους ασθενείς της ομάδας Β κατά την έναρξη και μετά από 4 χρόνια εφαρμογής της μεθόδου. Κανένας σημαντικός συσχετισμός δεν παρατηρήθηκε μεταξύ των ιστολογικών αλλαγών και των λειτουργικών δοκιμασιών και στις δύο ομάδες ασθενών. Συμπεράσματα: Σημαντικές δομικές αλλαγές του περιτοναίου παρατηρούνται στους ουραιμικούς ασθενείς και αυτές οι αλλαγές επιδεινώνονται με την εφαρμογή της CAPD. Οι δομικές αυτές αλλαγές δεν ακολουθούνται από λειτουργικές αλλαγές κατά τη διάρκεια των πρώτων τεσσάρων ετών σε CAPD. / The long-term exposure of peritoneal membrane to bioincompatible dialysis solutions leads to structural changes and loss of ultrafiltration capability. Objective: The aim of the present study is to describe the histological changes of peritoneum that are observed: a) in uremic patients and b) in patients that are in peritoneal dialysis for a period of time. Also to determine the possible relation of histological changes with the transport characteristics of peritoneal membrane and with adequacy of dialysis. Method: Thirty nine patients (M/F=18/19) that underwent a peritoneal biopsy in the initiation of treatment (group A, N=19) or after 4 years in continous ambulatory peritoneal dialysis (CAPD) (group B, N=18) were included in the study. The morphological changes of mesothelial cells and vascular compartment as well as the thickness of submesothelial collagenous zone were estimated. The relations of these changes to peritoneal equilibration test (PET) and to adequacy of dialysis (total weekly creatinine clearance (wClcr) and urea KT/V) were also investigated. Results: The main histological changes in both groups of patients were loss of mesothelial cells and decrease of normal mesothelial surface, thickening of submesothelial collagenous zone and presence of vascular hyalinosis. The thickness of submesothelial collagenous zone in both groups of patients was significantly higher compared to that of controls (630μm and 1140μm vs.50 μm respectively, p <0.05). Although no significant difference was found between morphologic changes of peritoneal membrane in uremic patients starting on CAPD and those on peritoneal dialysis for a mean period of 4 years, there was a trend towards more severe lesions in the latter. The PET, Clcr and urea KT/V were not significantly different in the two groups of patients. These parameters also showed no significant changes when examined in the initiation of CAPD and after four years in peritoneal dialysis in the same patients (group B). No significant correlations were observed between histological changes and PET, Clcr and KT/V in both groups of patients. Conclusions: Significant structural changes of peritoneal membrane are observed in uremic patients and these changes are deteriorated with CAPD treatment. Structural changes are not followed by functional changes during the first four years on CAPD.

The purpose of this study was to determine whether or not children diagnosed with Attention-Deficit Hyperactivity Disorder (ADHD) or Central Auditory Processing Disorder (CAPD) can be distinguished from one another on the basis of both objective and subjective assessment of attention and behavior. First, children and adolescents diagnosed with ADHD, CAPD, and concomitant ADHD/CAPD were compared to participants with emotional problems on measures of attention/concentration, depression, anxiety, and parental reports of internalzing and externalizing behaviors. Overall, statistical analyses did not reveal significant differences between performances of children diagnosed with ADHD and those diagnosed with CAPD. However, clinical comparisons across groups of children diagnosed with ADHD, CAPD, comorbid ADHD/CAPD and Affective Disorders revealed condition-specific clinical profiles, thus providing some support for CAPD as a distinct clinical entity. Second, exploratory cluster analysis was performed to further investigate the relationship between ADHD and CAPD. This procedure lead to the identification of four distinct clusters. However, analyses of these clusters revealed no distinct pattern of performance for children diagnosed with either ADHD or CAPD. Rather, participants with these diagnoses were evenly distributed throughout the clusters. Additionally, no cluster clearly represented the expected clinical profile for a diagnosis of CAPD- namely, significant auditory attentional/processing problems in the absence of other attentional difficulties. Implications for the assessment and treatment of childhood attentional disorders are discussed and recommendations for future research provided.

No description available.

No description available.

The Auditory Continuous Performance Test (ACPT) was evaluated on one group of subjects who had been diagnosed as having attention deficit-hyperactivity disorder (ADHD) and another group for whom ADHD had been ruled out. Although the specificity of the ACPT was acceptably high for a screening test, the sensitivity was very low. The conclusions drawn from these results are limited because of small sample size (n = 23). However, until reports based on large study samples are forthcoming, the use of the ACPT as a screening test for ADHD appears questionable.