Search PubMed⌕ Search

Biomedical subjects

S Chiaramonte

Publications and source records attributed to S Chiaramonte.

71 records · Page 4Linked to original sources
PubMed1982

Anatomical bases of peritoneal permeability: a reappraisal. Anatomy of peritoneum.

The peritoneal membrane consists of flat mesothelial cells linked together with digitations and containing vesiculae with pinocytic capacity, of endothelial cells (containing Weibel-Palade's bodies and vesiculae) and of an interstitial tissue consisting of a network of watery channels. The cellular structures of mesothelium and endothelium are characterized by tight and gap junctions or perhaps by macular junctions. The visceral peritoneum shows a prevalence of gap junctions, the pericysic veins contain only tight junctions while both types can be found in the arterioles. Two different ways for solute transport are theoretically possible: the vesicles of plasmalemma (via pinocytosis) and the junctions (via size-sieving effect). Studies with tracers did not furnish unequivocal data on this problem and did not clarify if these structures could be the equivalent of the pores of the Landis-Pappenheimer's theory. The studies of Karnowsky and Simionescu, using tracers, have in fact given opposite results.

Animals↗
PubMed1982

Pharmacokinetics of intravenous and intraperitoneal cefuroxime during peritoneal dialysis.

We investigated the pharmacokinetics of cefuroxime sodium, a new parenteral beta-lactam antibiotic, in 15 patients with stable chronic renal failure during intermittent peritoneal dialysis (IPD). Eight patients were administered 1 g cefuroxime as an intravenous bolus 1 h before the start of dialysis. Mean plasma levels of cefuroxime fell from 80 mcg/ml at 1 h to 40 mcg/ml at 6-8 h. At 24 h, concentrations were higher than 20 mcg/ml. In peritoneal fluid cefuroxime reached 16.7 mcg/ml at 1 h and 7.55 mcg/ml at 6 h. Seven patients received cefuroxime added to the dialysis solution at a dose of 2.5 g/10 liters. After 6 h of dialysis, cefuroxime reached plasma levels of 60 mcg/ml; after 24 h, concentrations were 37.5 mcg/ml. These results demonstrate that cefuroxime, administered by the i.v. route, easily diffuses from blood to peritoneal fluid and, from peritoneal fluid to blood when added to the dialysis solution. In both cases concentrations reached by cefuroxime are sufficient to treat peritoneal infections associated with peritoneal dialysis.

Adult↗
PubMed1981

Clinical significance of urinary fibrinogen degradation products in renal disease: study with two methods and correlation with histological findings of intraglomerular coagulation.

The investigation of fibrinogen degradation products (FDP) in urine has been suggested as a reliable method to detect the glomerular deposition of fibrin. Urinary FDP were investigated in 246 patients with renal disease by means of a latex test in 100 of them (positive in 54%); in the remaining 146 patients the Merskey method was used which gave positive results in 26% of them. A significant correlation between urinary protein excretion and FDP was only observed in those patients examined with the latex test. In patients investigated with the Merskey method, the simultaneous determination of serum FDP showed no correlation between FDP values in serum and urine. In those patients studied by means of renal biopsy, a poor correlation was observed between immunofluorescence and electron microscopic evidence of fibrin deposition and urinary FDP. In conclusion, isolated urinary FDP detection is not an index of pathologic coagulation in the glomeruli.

Biopsy, Needle↗
PubMed1981

Acid-base balance on peritoneal dialysis.

Forty studies of acid-base balance during intermittent peritoneal dialysis (IPD) and during continuous ambulatory peritoneal dialysis (CAPD) were performed on 20 patients who were receiving IPD with acetate buffer (5 patients), IPD with lactate buffer (5 patients), CAPD with acetate buffer (5 patients) and CAPD with lactate buffer (5 patients). Measurements of acetate, lactate and pyruvate levels in blood and dialyzate were taken at different times during dialysis; blood samples for blood gas analysis were drawn at the same times. Calculations of the kinetics of acetate, lactate and bicarbonate during IPD and CAPD were carried out according to the method of Tolchin [1977] but modified for PD. Thus it was possible to quantify the balance of the buffers, their mass transfer rates, bicarbonate generation and the percentage of buffer converted to HCO3. IPD kinetics of acetate and lactate were found to be similar, the main difference being a lower and significant percentage conversion of lactate to bicarbonate (45%) compared to that of acetate to bicarbonate (71%) (P < 0.005). On CAPD the kinetics of the two buffers was quite different: while the serum lactate level was always low (mean 0.97 +/- 0.33 mM/l), the acetate level was always high (mean 5.12 +/- 3.34 mM/l). Thus the utilization of the two buffers during "acute intermittent" treatment (IPD) and "continuous" treatment (CAPD) is different. On IPD there are no important differences between the two buffers, whilst on CAPD lactate seems to be better and safer than acetate; for instance, serum HCO3 values are relatively constant with lactate (27.7 +/- 2.13 mM/l) while with acetate there is a trend to exceed physiological values (29.5 +/- 1.7 mM/l). When acetate is used in the dialyzate for CAPD the concentration must be less than 38.5 mM/l.

Acetates↗
PubMed1979

125I-iothalamate and creatinine clearances in patients with chronic renal diseases.

In 196 adult patients with chronic renal disease or primary hypertension, the evaluation of glomerular filtration rate (GFR) by means of creatinine clearance, 'predicted' creatinine clearance and [125I]-iothalamate clearance was performed. Iothalamate clearance was evaluated after subcutaneous injection of the substance . In patients with normal or upper borderline plasma creatinine values, the iothalamate clearance ranged from 44 to 117 ml/min/1.73 m2 and the overestimation of GFR from creatinine clearance was negligible. In patients with mild or advanced renal failure, the overestimation of GFR from creatinine clearance increased up to 18 and 32%, respectively. The clinical usefulness of iothalamate clearance is evident especially in patients with mild renal failure, in whom an accurate evaluation of GFR is often important for a correct dietary and therapeutic approach.

Adolescent↗
PubMedDate not supplied

The importance of ultrafiltration on acid-base status in a dialysis population.

The amount of fluid withdrawn by ultrafiltration in a dialysis session plays an important role in regulating the acid-base status of patients. It has been previously demonstrated that an interdialytic weight gain of 3 kilograms requires the removal of 3 liters, mostly of extracellular fluid, which may contain 60-70 mMols of bicarbonate. Such losses require an increase in the buffer mass transfer to achieve a good buffer balance. The importance of interdialytic weight gain (IWG) on acid-base status was evaluated in two significantly different periods. In the period where the IWG was lower, predialytic pH and HCO3 were significantly higher than in the alternate period. Since dialysis schedule, dialysate buffer, daily protein intake and given medications did not differ during the two periods, we conclude that a reduced ultrafiltration due to less weight gain betters predialytic acid-base status.

Acid-Base Equilibrium↗
PubMedDate not supplied

Technical and clinical evaluation of a new system for ultrafiltration control during hemodialysis.

A new system for ultrafiltration control during hemodialysis is described. The apparatus consists of a computer operated system of load cells that register variations in weight of the outlet dialysate versus inlet dialysate. Once the weight loss of the patient has been established, the gravimetric control operates on the dialysate circuit to obtain the transmembrane pressure adequate to achieve the desired ultrafiltration rate and patient weight loss. The system can be used as a complete dialysis machine or as a separate module that can be adapted to any standard dialysis machine. This module was tested in more than 220 dialysis sessions, using different membranes and ultrafiltration rates. The difference between the scheduled and the real weight loss was always less than 100 g at the end of the dialysis session. The number of technical interventions required were few, as was the rate of complications related to the system. The system is safe and reliable and offers a low cost opportunity to improve dialysis tolerance by accurate and progressive ultrafiltration during the session.

Body Weight↗
PubMedDate not supplied

Total solute extraction versus clearance in the evaluation of standard and short hemodialysis.

The authors compared the efficiency of standard HD (t = 240 minutes, Qb = 300 ml/min, Qd = 500 ml/min) with short HD (t = 150 minutes, Qb = 500 ml/min, Qd = 700 ml/min). The study was carried out in 11 patients in two sequential dialysis sessions, utilizing the same high surface area hollow fiber dialyzers, after a 2 day interdialytic period. With short HD, as expected, the clearance (Cl) of BUN, creatinine (Cr), and phosphates (P) was significantly higher than in standard HD:Cl BUN = 331 vs. 225, Cl Cr = 286 vs. 193, and Cl P = 231 vs. 176 ml/min. No significant difference in the total BUN extraction (measured on the total amount of exhausted dialysate) was found between the two techniques. As to Cr and P, despite higher Cl in short HD, the total extractions were significantly lower. In conclusion, in the evaluation of short HD efficiency, instantaneous Cl can be adequate for small molecules, while for larger solutes, other parameters, such as total extraction, must be considered.

Blood Flow Velocity↗