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The thyroid status was studied in 19 uremic patients (11 on HD and 8 on CAPD) and in a group of 17 healthy adult patients. In uremic patients T3and T4were significantly reduced (p < 0.001) and rT3was increased (p < 0.001). The time course TSH response to TRH showed a lower peak response (in 5 patients it did not exceed 5 μU/ml) which on turn was also delayed (the peak was observed at 60 minutes in 63% of them). TSH concentrations in uremics were increased at 0 time (p < 0.02), lower at 20 minutes (p < 0.01) and increased at 120 minutes (p < 0.02). No difference existed between HD and CAPD. The thyroid response to TSH was normal as showed by a normal percent increase over basal values of T3concentrations at 120 minutes. Uremic patients also showed a peak GH response at 20 minutes which was not observed in controls. The data exclude the existence on a primary form of hypothyroidism and point to the existence of hypothalamic-pituitary abnormalities, which should not be taken as indicative of secondary and/or tertiary hypothyroidism since FT4values were normal in HD and increased in patients undergoing CAPD (p < 0.05) who on turn showed lower plasma albumin concentrations (p < 0.05).

Thyroid function was measured in 30 healthy subjects and 84 patients with various degrees of nephron loss (GRF: 70 ± 15 m/min, 30 ± 16 ml/min, 10 ± 7 ml/min and 2.1 ± 1.3 ml/min).A low T3and T4syndrome is evident when GRF is reduced to 30 ± 16 ml/min while a blunted TSH response is detected earlier in the course of nephron loss. T3response to TRH was normal and FT4was not affected by renal dysfunction. The data indicate that in nephron loss hypothalamic-pituitary abnormalities occur.

Sclerosing peritonitis is a serious complication in patients on long-term peritoneal dialysis; it markedly decreases transport of water and solute across the peritoneal membrane. Although the precise mechanism is unknown, organic compounds (i.e., plasticizers) from plastic tubing and dialysis bags have been suggested to be a cause of the syndrome. The effects of three such compounds on water and sodium transport in vitro were studied in the toad bladder. The compounds studied were didodecylphthalate, dioctylphthalate, and benzylbutylphthalate. After 4 hr incubation in vitro, dioctylphthalate and benzylbutylphthalate significantly inhibited vasopressin-stimulated water flow in toad bladder. Basal water flow was not affected by any of the three compounds. Sodium transport, as measured using short-circuit current, was decreased to an equivalent degree by all compounds; inhibition of short-circuit current was dose dependent and was approximately 30% at 10(-3) M. The onset of action was between 3.5 and 4 hr, and the effect on short-circuit current was not reversible. These results demonstrate that the plasticizers (to which patients of all sorts are commonly exposed) inhibit transport across living membranes. In the toad bladder these compounds decrease sodium transport and maximal water flow. Although other evidence suggests that the cumulative toxic effects of these compounds may play a causal role in sclerosing peritonitis in patients on peritoneal dialysis, our study suggests that chronic exposure to the phthalate acid esters in patients with normal renal function may result in sodium wastage, polyuria, and a concentrating defect resistant to AVP.

Thyroid function was explored in 27 CAPD patients and 25 HD patients. Dialysis was associated with low T3and T4levels, increased rT3concentrations, normal T4: T3and reduced T4: rT3ratios, normal FT3and Thyroglobulin concentrations. TSH levels increased during dialysis but still fell within normal limits. The data rule out a condition of primary hypothyroidism and point out to increased thyroidal dismission associated with the block T4-T3in peripheral cells. Also the increased FT4levels in CAPD patients could be due to de novo dismission of thyroidal T4.

Since the introduction of hemodialysis procedure several attempts have been made to elucidate the material tissue interaction in order to evaluate the behaviour of immunosystem cellular and humoral responses to the material of patients on renal replacement therapy. Biochemical and sierological parameters have been considered as method for assessment of the best compatible dialysis. Nevertheless blood tests don't probably reflect the most important symptoms of clinical relevance. Thus we have applied bioelectrical impedance to assess the whole procedure/patient system. Resistance (R) changes during hemodialysis resulted strictly inversely correlated to the body weight variations during HD session (R < 0.96). Reactance (Xc) has also shown a progressive increase associated with an increment of phase angle, while Xc during clinical events such as hypotension, vomiting or cramps showed some transient falls. Also nutritional status and clinical well-being manifested a close relationship with bioelectrical parameters. It is therefore our feeling that BIA monitoring will provide a feasible tool to assess dialysis adequacy, of which biocompatibility represent a crucial aspect.

Among 55 uremic patients who entered our CAPD program, 7 of them showed a reduction or loss of the ultrafiltration capacity (UF) of the peritoneal membrane (PM). They have been treated with high dose of Furosemide (F) to force residual urine output. Four appeared «responders» to drug administration with a significant increase in urine volume, Na excretion and, within a week period gained their dry body weight (BW).In the remaining 3 patients drug therapy resulted ineffective, and fluid removal was obtained by hemofiltration (HF).In both groups we noted an increase in the UF capacity of PM when their dry BW was obtained either by pharmacological or technical approach.These results support the assumption that the overhydration status of the PM plays a major role in maintaining the UF process.

Twenty-eight diabetic patients (25 in good metabolic control and 3 with ketoacidosis) were studied.

Lysagth et al have reported a semplified model of spontaneous plasmapheresis by placing between an A-V shunt a conventional plasmafilter. On the basis of this experience we tried to make a further semplification of this apparatus using a single venous puncture, obtaining by gravity sufficient transmembrane pressure for plasma separation. By alternatively lowering and elevating the system, plasma is separated from the blood and packed red cells are reinfused after a new pass through the filter with FFP or plasma substitutes.

Abstract. We have measured by a computed integrated system (BIA 109, RJL AKERN) the changes of bio-impedance (BI) deriving from a tetrapolar system working on 800 μA, 50 kHz current, in 23 haemodialysed patients. Resistance (R) and reactance (Xc) have been continuously monitored during haemodialysis in each patient. Resistance was strictly inversely correlated to the decrease of body weight (r=0.82). Also, Xc increased almost constantly. In most of the patients the increase of Xc was proportionally greater than R, resulting in an increase of phase angle (PA). However, Xc showed a transient decrease in response to seven severe symptomatic hypotensive episodes, whereas R maintained the increasing trend, causing a sharp reduction of phase angle. As Xc is an expression of storage of electrical charge by the cells acting as condensers, and phase angle quantifies the active capacitive component in relation to passive electrical resistance, these parameters may be important to evaluate cell membrane function. In fact, the univocal increase of R, Xc and phase angle observed during normal uneventful haemodialysis probably indicates improvement of cellular activities due to the depurative treatment. On the contrary, the transient reduction of Xc and phase angle observed during hypotensive crises may be an expression of cellular distress because of a too rapid ultrafiltration.