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Thyroid function tests were evaluated in 38 patients on regular hemodialysis (HD), in 36 on continuous ambulatory peritoneal dialysis (CAPD) and in 39 healthy controls. A significant reduction in total thyroxine (TT₄), total triiodothyronine (TT₃), reverse (rT₃), and free T₄ (fT₄) mean levels and normal TSH, free T₃, TBG and albumin concentrations was found in both HD and CAPD patients. A ‘low-T₄ syndrome’ (serum T₄ < 5 μg/dl) was found in 9 CAPD (25%) and 20 HD (53%) patients, but none of them had fT₄ levels below the normal laboratory range. The only striking difference between low-T₄ HD and low-T₄ CAPD patients was the significantly lower TBG and albumin serum levels in CAPD group. Low-T₄ HD displayed normal TBG levels but enhanced fT₄/TT₄ and TT₄/TT₄ × TBG ratios. We concluded that: (1) the abnormalities in thyroid function tests in patients on long-term dialysis (HD and CAPD) do not express the existence of a true hypothyroidism; (2) a different pathogenesis of the low-T₄ syndrome in the CAPD and HD groups may be hypothesized: in the former it could be attributed to a reduction in serum-binding capacity for thyroid hormones, in the latter the relative increase in fT₄ percentage despite normal TBG levels suggests either the presence of T₄-TBG-binding inhibitor (s), or structural abnormalities of thyroid-hormone-binding proteins.

Objective To investigate the effect on the patient's acidbase status of a 39 mmol/L bicarbonate-buffered continuous ambulatory peritoneal dialysis (CAPD) solution. Design This was an open, controlled, cross-over, two-center study in 9 patients. After three months of treatment with a 34 mmol/L bicarbonate-buffered solution (to) patients were switched to a 39 mmol/L bicarbonate-containing solution for four weeks. At the end of the study period (t4) patients were again treated with a 34 mmol/L bicarbonate-buffered CAPD solution for one month (t8). Results Mean venous plasma bicarbonate level significantly increased during the study and decreased at the baseline level during the control period (to = 22.94±2.54, t1 = 26.74±3.07, t2=28.47±2.68, t3=28.11±3.56, t4=28.71±3.27, t8=24.94±2.56). Arterial blood pH and plasma bicarbonate significantly increased during the study and significantly decreased attheend of the control period (pH: to= 7.37±0.04, t4= 7.42±0.04, t8= 7.37±0.06. Bicarbonate: t0= 21.97±2.57, t4= 25.85±2.02, t8= 21.87±2.89). The changes in plasma bicarbonate during the study period were inversely correlated with the metabolic acid production calculated from the protein catabolic rate and with the apparent distribution space for bicarbonate (ABS) of patients. Conclusions The 39 mmol/L bicarbonate-buffered CAPD solution improved the patient's acid-base status. Potential undesirable metabolic alkalosis could be prevented by analyzing the ABS and the metabolic acid production of patients.

Cardiac hypertrophy, a well-known independent risk factor for cardiovascular death, is a very frequent complication in ESRD patients. Its frequency tends to be even higher in dialyzed patients due to the fact that the current dialytic treatments are unable to keep under a satisfactory control the various responsible factors and particularly the blood pressure, which is largely the most important. Daily hemodialysis, a more frequent schedule consisting of 6–7 sessions/week lasting 2 or more hours, has definitely proved its superiority in controlling blood pressure and in improving anemia, and thus has the requisites for positively influencing cardiac hypertrophy. In fact, a series of studies, both retrospective and prospective, performed during the last years by our group, have confirmed that this new, more frequent and thus more physiological schedule, is able not only to stop the progression of the cardiac hypertrophy in uremic patients but also to revert toward the normality, in a relatively short time. This appears to be essentially a consequence of the excellent blood pressure control, which in turn derives from the easier control of the true dry weight, achievable with this type of dialytic treatment.

Objective Isoprene is the constitutive unit of isoprenoid lipids and sterols. However, it is also a potential toxic and carcinogenic agent. Recent findings of a marked and prolonged isoprene overproduction induced by hemodialysis sessions raises the question of isoprene behavior in patients on peritoneal dialysis. Design A study with repeated measures per patient and healthy control. Setting Nephrology and Dialysis Unit and Perugia University Medical School. Patients Sixteen consecutive patients on regular continuous ambulatory peritoneal dialysis (CAPD) were evaluated. Endogenous isoprene was analyzed using gas chromatographic assay of breath isoprene, collected at set times before and after dialysis fluid exchange. Results No significant variations were found in breath isoprene concentrations in the different samples from each patient, and levels were almost stable within the normal range of healthy controls. Conclusion These results show that CAPD, unlike hemodialysis, has little or no effect on isoprene and isoprenoid-related lipid turnover. This lack of increased endogenous isoprene synthesis, in addition to being a distinctive metabolic feature of CAPD, could have important pathophysiological and clinical implications.