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S Alloatti

Publications and source records attributed to S Alloatti.

At least 19 recordsLinked to original sources
PubMed1997

Relation between blood pH and ionized calcium during acute metabolic alteration of the acid-base balance in vivo.

We induced metabolic alkalosis and acidosis in 10 healthy volunteers in order to analyse in vivo relation between pH and ionized calcium (cCa2+). In the alkalinization test, 2.7 mol/kg NaHCO3 was injected. In the acidification test, volunteers took 4 mmol/kg NH4Cl. Blood pH and cCa2+ (mmol/l) mean values (SD) baseline, after alkalinization and acidification tests, were: 7.363 (0.018), 7.456 (0.031), 7.244 (0.031), 1.27 (0.03), 1.14 (0.03) and 1.38 (0.04). Mean slope of regression log cCa2+/pH was -0.39 (SD 0.11). Such a slope differs after in vivo or in vitro changes, due to the in vivo rapid restoration of equilibrium between the plasmatic and interstitial compartments following changes in water and electrolyte concentrations. The type of acid-base alteration-respiratory or metabolic-influences pH changes, and consequently the regression slope. The in vivo slope for log cCa2+/pH in normal subjects (-0.21) is much the same as in acute respiratory alterations (-0.17), whereas it differs in acute metabolic alterations (present study). Bicarbonates play different roles: the same changes in pH cause greater changes in cCa2+ after acute metabolic rather than respiratory alterations. Ca2+ homeostasis is maintained in acute respiratory acid-base imbalance, despite wide shifts in pH, whereas in acute metabolic alterations even small pH changes have striking repercussions on cCa2+. The experimental angular coefficient for in vivo acute metabolic acid-base alterations differs from the theoretical one calculated by Thode's differential equation (-0.25).

Acid-Base Equilibrium↗
PubMed1997

[Diagnostic aspects in the determination of antineutrophil cytoplasmic antibodies].

We propose a four step flow-chart to define ANCA positivity and antigenic target. 1st step: indirect immunofluorescence test on ethanol-fixed human granulocytes (IIF-E), as screening test. Different staining patterns can be observed: a granular cytoplasmic fluorescence (C-ANCA), a smooth or fine granular perinuclear fluorescence (P-ANCA) and an intermediate pattern (X-ANCA). Antinuclear antibodies (ANA) may mimic P-ANCA. 2nd step: IIF test on formalin-fixed human granulocytes (IIF-F) differentiates true P-ANCA from ANA: most of P-ANCA show cytoplasmic pattern, whereas ANA are negative. 3rd step: IIF test on monkey liver sections (IIF-M) investigates simultaneous ANA and P-ANCA positiveness. P-ANCA positive sera show an exclusive reactivity with neutrophils infiltrating the portal tract, whereas ANA react with hepatocytes nuclei. 4th step: to characterize antigenic target, a solid phase assay, using purified proteins as substrates, is performed. We found 17 C-ANCA (6 PR3, 3 MPO, 1 Lys, 1 Cat G and 6 unknown antigens) out of 173 patients screened with IIF-E. 21 P-ANCA positive sera have been investigated by IIF-F test: 15 showed a cytoplasmic pattern; EIA test gave the following results: 6 MPO, 2 LF, 5 unknown antigens; 2 cases were positive for two antigens, MPO & LF. Using IIF-M on the 6 IIF-F negative sera, we observed: 2 false positives (ANCA-/ANA-), one ANCA+/ANA+ (antigen LF), 3 ANCA+/ANA- (unknown antigens). The flow chart suggested allows to analyse in detail ANCA, using easily available commercial kits.

Animals↗
PubMed1996

Agreement between the classical urea kinetic model and direct dialysis quantification: importance of urea rebound.

From a review of the literature regarding kinetic models used for assessing the adequacy of hemodialysis, no definite conclusions can be drawn as to whether the classical urea kinetic model (UKM) or modified direct dialysis quantification (mDDQ) is more reliable. We compared mDDQ with classical UKM and with a modified UKM that employs an equilibrated urea value. From the theoretical viewpoint, no substantial conflict is found between the two models as regards the dialysis dose, if urea rebound is considered. From the practical viewpoint, in our opinion direct quantification lends itself better for experimental purposes whereas for routine Kt/V evaluation UKM is easier and accurate enough, provided that rebound is taken into account.

Female↗
PubMed1996

[Proposal of new formulas for three-point urea kinetics, compared with traditional kinetics and direct dialysis quantification].

Classical urea kinetic model (UKM) has been followed by several proposals to determine dialysis adequacy either by direct quantification (DDQ), either by simplified two-points formulas (pre- and post-dialysis BUN), or by mUKM, a modified three-point algorithm (pre-post and pre-next dialysis), where urea distribution volume is input to obtain clearance and urea generation rate. Our new formulas (mUKM2) are derived from urea mass balance, and avoid iterative calculation: their results are similar to those obtained by UKM and mUKM when the standard post-dialysis BUN value is employed. On the contrary, when the equilibrated net-rebound value (Cpwnr) is employed their results are very close to the reference DDQ model: however the new approach is simpler and more practical, to measure dialysis dose taking account of the urea rebound phenomenon.

Female↗
PubMed1996

[Use of dual energy X-ray absorptiometry (DEXA) in the determination of total body water in patients undergoing chronic dialysis].

In order to assess Total Body Water (TBW), three methods are compared, in 18 patients on regular dialysis treatment: DEXA, Bioimpedance Analysis (BIA) and urea Kinetic Volume (V urea). The mean difference between gravimetric weight and Total Body Mass (TBM) DEXA is closed (1.04 kg, SD of differences 0.4 kg). The mean difference between delta pre-post HD gravimetric weight loss (2.6 kg) and delta pre-post TBM DEXA is--0.03 kg (SD 0.28). TBW measured with the three methods are (Liters): TBW DEXA = 31.2 (SD 5.2), TBW BIA = 29.7 (SD 5.2), TBW V urea = 29.1 (SD 4.8). TBW comparisons between the three methods are (Liters): TBW DEXA-TBW BIA = mean 1.5 (SD 3.8), r = 0.73. TBW DEXA-TBW V urea = mean 2.1 (SD 2.2), r = 0.88. TBW BIA-TBW V urea = mean 0.6 (SD 3.6), r = 0.80. Hydration index of lean body mass, calculated by assuming V urea as standard, is 0.69 (SD 0.05), range 0.62-0.77, in agreement with others studies. In conclusion DEXA, a useful method for body composition and nutritional status assessing, represents a new tool for measuring hydration status, combined with others TBW evaluation formulas (BIA or V urea).

Absorptiometry, Photon↗
PubMed1995

On-line dialysate urea monitor: comparison with urea kinetics.

The outputs of a new on-line dialysate urea monitor (UM) were compared to a urea kinetic model (UKM) and to dialysis direct quantification (DDQ) in 13 patients. As for urea extraction and predialysis urea level, a good degree of correspondence was found between UM and laboratory data. Kt/VUM (1.21) is intermediate between Kt/VUKM (1.28) and Kt/VUKM using the post-rebound urea value (1.14) or Kt/VDDQ (1.14). Passing and Bablok regression analysis indicated no systematic error between Kt/VUM and Kt/VDDQ. The percentage differences in nPCR by UM, UKM and DDQ were not significant, but the standard deviations were wide. The UM approach is very simple and practical, avoiding blood sampling, laboratory analysis and data handling. It is reliable enough for clinical practice. Compared with traditional urea kinetics, Kt/V computation by a mathematical elaboration of the dialysate urea profile drawn from several points theoretically invites fewer errors due to the analytical procedure.

Adult↗
PubMed1992

Follow-up of nerve conduction in chronic uremic patients during hemodialysis.

We studied to evolution of nerve conduction during hemodialysis following 21 patients with chronic renal failure. Mean motor nerve conduction velocity (MCV) was significantly different at hemodialysis onset and 3 years later for both common peroneal nerve (44.5 and 41.0 m./sec.) and ulnar nerve (52.5 and 47.1 m./sec.). MCV decreased more in patients with low Kt/V (a depuration index) than in those with high Kt/V.

Adult↗
PubMed1989

Scant reliability of Co/Ct ratio in urea kinetic formulas.

The ratio initial/final urea value is used in urea kinetic formulas. To assess its reliability we employed mass balances and urea clearances to study 15 hemodialysis treatments divided in several parts. The mass balances clearly indicated urea disequilibrium. In the first phases of dialysis, urea extraction, measured by dialysate collection, was lower than the corresponding change in urea pool, whereas in the later phases the opposite occurred. On account of this lack of equilibrium, clearances bases on the Co/Ct ratio (K2) are less reliable than standard clearances derived from total dialysate collection (K1): in the first quarter of dialysis, K2 is greater than K1 (p less than 0.01), while in the 3rd and 4th quarters it is lower. The comparison of clearances in a cumulative way showed a significant fall in K2 (p less than 0.01) while K1 remained stable. From a practical point of view, aberrations induced by non monocompartmental urea behaviour are negligible, and do not invalidate the usefulness of the single-pool Gotch model in clinical practice. However, at least in experimental work, the limits of urea kinetic formulas must be taken into account.

Humans↗
PubMed1982

Clinical significance of the detection of circulating immune complexes in lupus nephritis.

32 patients (22 biopsed) with lupus nephritis (LN) were observed for circulating immune complexes (IC). Solid phase C1q (SPC1q) and polyethylene glycol (PEG) precipitation tests were used. The patients were studied during the clinical follow-up in different phases of disease activity. Comparative studies between each histological class of LN and corresponding forms of idiopathic glomerulonephritis (IGN) were made: no significant differences were found between either mesangial LN and stalk mesangial IGN, or between focal proliferative LN an focal proliferative IGN. However, a significant difference was found for SPC1q data between diffuse proliferative LN and mesangiocapillary IGN, and between membranous LN and membranous IGN. LN, with an acute nephritic syndrome and hypocomplementemia, displayed SPC1q data significantly above the levels of IC found in IGN with similar clinical features. IC serum data would seem an important element for the diagnosis and the clinical management of patients affected by LN.

Adolescent↗
PubMed1982

The immunological state in chronic renal insufficiency.

To evaluate the immunological state in chronic renal insufficiency, the Authors studied cellular and humoral immunity in 292 patients with chronic renal failure. They were divided into 3 groups: 1) 37 with creatinine clearance between 50 and 20 ml/min; 2) 57 with creatinine clearance between 20 and 8 ml/min; 3) 178 treated by hemodialysis. In vivo and in vitro tests, that is DNCB, PPD skin tests, spontaneous, active and EAC rosettes, surface membrane immunoglobulin test, complement (C3, C4) and serum immunoglobulins were taken as markers of the immune response. Cell-mediated immunity was found to be significantly impaired in patients with terminal renal insufficiency or on hemodialysis and also markedly reduced in patients with non-terminal renal insufficiency. Humoral immunity produced less significant results: the B lymphocyte count and serum immunoglobulins were normal; only C3 levels were found below normal range. Thus it would seem that cell-mediated immunodeficiency appears in an early stage of chronic renal failure and that hemodialysis does not improve this deficiency.

Adult↗
PubMed1981

Effects of blood transfusion on cellular immunity.

To evaluate the effect of transfusion on immunity, 14 uraemic patients treated with 3 blood transfusions from a single donor, at weekly intervals, were studied: in 5 cases HLA-A,B were compatible, in 9 cases they were not. As markers of cellular and humoral immunity DNCB, PPD skin tests, spontaneous and active E-rosettes, EAC-rosettes, surface membrane immunoglobulins, C3, C4, C3d, serum immunoglobulins, circulating immune complexes and C-reactive protein were investigated. This protocol was applied before transfusions, 1 week after each transfusion (day +7, +14, +21) and 20 weeks later (day +80). Before transfusions 8/14 patients were DNCB negative; both spontaneous and active E-rosettes were below normal range. The other parameters were normal. On day +7 T and B lymphocytes were increased, while the other parameters were unmodified. On day +21 there was a significant reduction (p less than 0.5) in T lymphocytes in patients treated with compatible transfusions. On day +80 3/3 DNCB positive patients, treated with compatible transfusions, became negative and 1/3 DNCB positive patients, treated with random transfusions, also became negative. Three/fourteen patients showed a decrease in B lymphocytes. The other results were unchanged. Our preliminary results suggest that transfusions, either from an HLA compatible donor or not, can impair lymphocyte function.

Adult↗
PubMed1975

[Use of coil negative pressure in the kidney].

A sealed compartment recycling system has been created for use with Extracorporeal commercial filters in order to exploit the negative pressure of the dialysate for purposes of ultrafiltration. The results of in vivo and in vitro tests regarding ultrafiltration and dialysates of urea, creatinine, Hipaque I125 and vit. B12 Co57 are reported. The tests highlighted improved dehydration characteristics in the system compared with the traditional coil technique, while the dialysates of small and medium molecules showed no decrease. The system can profitably be used as an alternative to the open compartment coil system and is particularly interesting because it can be combined with monitors which provide exclusively for the use of closed circuit dialysate instruments.

Creatinine↗