1,721,140 research outputs found
Alterazioni dell’equilibrio acido-base
No full textConsiderazioni generali
I meccanismi fi siologici che regolano l’equilibrio acidobase
(EAB) rispettano gli stessi principi di mantenimento
dell’omeostasi che governano il bilancio di molte sostanze
in ingresso o in uscita dall’organismo (acqua, sodio ecc).
Un aspetto specifi co dell’omeostasi dell’EAB è rappresentato
dalla presenza dei sistemi tampone e dal coinvolgimento
principale di due organi (rene e polmone) che si
bilanciano e all’occorrenza si compensano per concorrere
a questa omeostasi.
In condizioni normali la concentrazione dello ione H + [H + ]
nel sangue è estremamente bassa (40 × 10 −9 M = 40 nmol/L)
per cui Sorensen, per semplifi care l’utilizzo di questi numeri,
ha proposto l’impiego del logaritmo negativo, e
quindi del pH (pH = − log 10 [H + ]). Il valore di [H + ] nell’organismo
è peraltro sottoposto a rigido controllo perché
molte reazioni enzimatiche risentono delle sue variazioni.
Il range normale di pH è di 7,35-7,45 corrispondente a
una [H + ] di 45-35 nmol/L
Le alterazioni del volume e della composizione elettrolitica dei liquidi corporei.
No full textLe alterazioni del volume e della composizione dei liquidi corporei sono manifestazioni frequenti di numerose malattie ed il loro rapido riconoscimento e trattamento diventa essenziale per ripristinare il normale stato di salute. Il bilancio corporeo dei liquidi, variabile dalla grave iperidratazione (anasarca) alla disidratazione, è strettamente collegato al contenuto elettrolitico corporeo; dalla loro interazione dipende la distribuzione dei fluidi tra i diversi compartimenti, l'osmolalità dell'extra e dell'intracellulare, e la funzione metabolica cellulare
Water quality for on-line haemodiafiltration.
No full textThe term 'ultrapure water' is a common way to define water used for on-line treatments: it refers to the absence of chemical, organic and microbiological contamination. To be more accurate in definition, every known and potential contaminant has to be fixed at its limit value. AAMI recommendations and various Pharmacopoeias have set limits for dialysate based on traditional dialysis treatments, but on-line treatments should also be regulated by guidelines for infusion solutions. Modern water treatment technology allows us to obtain a proper chemical quality both for dialysate and infusion solutions in on-line dialysis. Technology alone, however, cannot guarantee adequate microbiological quality if water treatment is not linked to the appropriate maintenance, monitoring, cleaning and sanitizing procedures. On-line dialysis treatments, as well as high-flux dialysis, use the monitor as an on-site pharmaceutical factory where sterilization by filtration forces nephrologists to look for procedures to keep sterile water sterile
Hemorheology in kidney transplantation: A role for cardiovascular risk?
No full textUremic patients undergoing dialysis (HD) present a cardiovascular risk of death 10-20 fold higher than general population, but also kidney transplantation keeps considerable cardiovascular burden.Hemorheologic profile alterations have been described in HD; comprehensive data on kidney transplant recipients (KT) are missing. Aim of our study is to characterize the hemorheological profile in KT, and to compare these data with HD and healthy volunteers (HV).We investigated 47 HV, 90 HD and 108 KT.We confirm hemorheological alterations in HD. KT, when compared to HD, normalizes many parameters: plasma viscosity, whole blood viscosity at 1-Hz and 200-Hz shear rate, erythrocyte aggregation index and yield stress. KT show a markedly lower erythrocyte deformability (ED). We found no differences among hemorheological parameters between the different classes of immunosuppressive drugs used.In conclusion, HD show various hemorheological defects; this could support the high incidence of cardiovascular complications. KT improves most hemorheological alterations; nevertheless, ED is reduced in KT, maintaining a detrimental injury at microcirculatory level and leading to the progression of fibrosis till to end-stage injury. Impaired ED in KT could also contribute to progression of interstitial fibrosis and tubular atrophy (IF/TA) in grafts
Reply to the letter of Dr Merdin
Full text linkDr Merdin kindly makes suggestions about the design of our study and asks for more information about the infectious and immunosuppressive history of our monoclonal B‐cell lymphocytosis (MBL) patients with monoclonal B‐cell lymphocytosis (MBL). In our study, we incidentally found the coexistence of five cases of MBL and monoclonal gammopathy of undetermined significance (MGUS) in a cohort of kidney transplant recipients at a median of 15 years after transplantation.1 MBL and MGUS are two pre‐malignant lymphoproliferative disorders of terminally differentiated B cells. Clinically, MBL and MGUS share common features, such as an indolent course, a late‐onset age distribution, a low rate of progression and an increased susceptibility to infections. MBL and MGUS are also the precursor states of two hematologic malignancies: chronic lymphocytic leukemia (CLL) and multiple myeloma (MM), respectively
Heparin and dialysis: reasons to make a change?
No full textThe availability of heparin was undoubtedly one of the main factors contributing to the widespread use of clinical dialysis: although lipolytic activity, osteoporosis and thrombocytopenia were described, clinical advantages remained unrivalled until today. Nevertheless, several effects attributable to heparin are less widely recognized, though theoretically noteworthy. Heparin has immunosuppressive properties, interfering with both humoral and cell-mediated immunity [1–2]: these actions should be probably taken in to account since dialysis patients are prone to infections and receive an average of 500000–1 million units/year of heparin. Heparin is able to split the activin–follistatin complex, allowing activin to stimulate smooth muscle cells of vessel wall to proliferate [3]; the risk of systemic atherosclerosis could therefore be increased [4]. In addition, by the same mechanism heparin could favour the process of intimal hyperplasia leading to stenosis, usually observed just at the venous end of vascular access, the site where dialysis-administered heparin concentration is higher than in any other site of the vessel system. Finally, the source of heparin could be of some concern after description of the variant of Creutzfeld-Jacob encephalopathy (vCJ) as a prion disease transmitted by cows suffering from BSE. Of interest, it was reported that there was an increased risk of sporadic CJD for patients undergoing surgery, unfortunately without explanation of the mechanism(s) involved [5]. Intra-operative or prophylactic post-operative heparin administration could not be ruled out. Since heparin can be extracted from beef or pork offal, beef-derived heparin should be re-evaluated for medical use and dialysis patients suffering from encephalopathies should be screened for vCJ. Apart from the more specific mode of action [6], recombinant hirudin should be considered if the safe origin of heparin cannot be certified
Which is the preferred vascular access in diabetic patients? A view from Europe
No full textNo abstract available
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