Social support from health care providers is associated with reduced illness intrusiveness in hemodialysis patients.

BACKGROUND: End-stage renal disease (ESRD) disrupts patients' life styles, interests and activities negatively affecting their quality of life. Social support has been previously associated with favorable health outcomes. However, no study has examined the association of social support from health care providers with perceived health and ESRD intrusiveness on patients' lives. METHODS: A self-administered questionnaire was completed by 1,238 Italian hemodialysis patients. The Self-Rated Health (SRH) and the Illness Intrusiveness Rating Scale (IIRS) assessed disease burden. 10 items assessed social support from health care providers (SS-HC). The nursing staff of each center provided patients' clinical information. Linear regression was used to assess correlates of SRH and IIRS. Mediational analysis was used to assess direct and indirect associations of SS-HC with SRH through IIRS. RESULTS: Higher SS-HC was associated with smaller IIRS and higher SRH. Further correlates of better SRH were younger age, no post-dialysis hypotension, no diabetes and cardiovascular diseases, better sleep quality, and smaller burden of oral therapy. CONCLUSIONS: Our results suggest that social support might reduce illness burden and improve patients' perceived health. Further research should assess the efficacy and cost-effectiveness of structured support programs for dialysis patients.

Effective glomerular filtration pressure and single nephron filtration rate during hydropenia, elevated ureteral pressure, and acute volume expansion with isotonic saline.

Free-flow and stop-flow intratubular pressures were measured in rats with an improved Gertz technique using Landis micropipets or a Kulite microtransducer. In hydropenia, average single nephron glomerular filtration rate was 29.3 nl/min, glomerular hydrostatic pressure (stop-flow pressure + plasma colloid osmotic pressure) was 70 cm H(2)O and mean glomerular effective filtration pressure was 12.7-14.3 cm H(2)O, approaching zero at the efferent end of the glomerulus. Thus, the glomerulus is extremely permeable, having a filtration coefficient four to five times greater than previously estimated. Mean effective filtration pressure and single nephron glomerular filtartion rate fell with elevated ureteral pressure and rose with volume expansion, more or less proportionately. Changes in effective filtration pressure were due primarily to increased intratubular pressure in ureteral obstruction and to reduced plasma colloid osmotic pressure in volume expansion; glomerular hydrostatic pressure remained constant in both conditions and thus played no role in regulation of filtration rate.

Polyuric prerenal failure after reduction from high to normal dietary intake of sodium.

In a patient with renal amyloidosis secondary to chronic urinary tract infection with nephrotic syndrome, polyuric acute renal failure developed after reduction from a high to a normal dietary intake of sodium and was reversed by salt replacement therapy. As documented by functional and morphological studies, the patient had a marked defect of tubular sodium reabsorption at the proximal site and along the ascending limb of Henle's loop, a distal tubular unresponsiveness to aldosterone, and severe tubulointerstitial damage in the medulla. We propose that the sodium dietary reduction in conjunction with severe tubular dysfunction and hypovolemia due to nephrotic syndrome is responsible for this unused form of polyuric acute prerenal failure.

[The Dialysis Outcomes and Practice Patterns Study (DOPPS): results of the Italian cohort]. / Lo studio DOPPS (Dialysis Outcomes and Practice Patterns Study): risultati della coorte italiana.

BACKGROUND: The Dialysis Outcomes and Practice Patterns Study (DOPPS) is an international prospective, longitudinal, observational study examining the relationship between dialysis unit practices and outcomes for hemodialysis (HD) patients in seven developed countries France, Germany, Italy, Spain, United Kingdom, Japan and the United States. Results of the DOPPS in Italy are the subject of this report. METHODS: A national representative sample of 20 dialysis units (21 in Germany) was randomly selected in each of the European DOPPS countries (Euro-DOPPS). In these units, the HD in-center patients were included on a facility census, and their survival rates continuously monitored. A representative sample of incident (269 in Italy, 1553 in the Euro-DOPPS) and prevalent (600 in Italy, 3038 in the Euro-DOPPS) patients was randomly selected from the census for more detailed longitudinal investigation with regard to medical history, laboratory values and hospital admission. RESULTS: Comparing the Italian and Euro-DOPPS cohorts we found comparable mean age for prevalent patients (61.4 vs. 59.5 yrs), but incident patients were older in Italy. Italian prevalent patients had less cardiovascular disease, more satisfactory nutritional status and more frequent use of native vascular access. These data were associated with a comparable mortality (15.7 vs. 16.3 deaths/100 patient yrs), but morbidity was lower in Italy. Kt/V levels were comparable in the two cohorts (1.32 vs. 1.37), but 35% of Italian patients showed a Kt/V below the recommended target. Moreover, hemoglobin levels were below 11 g/dL in 60% of Italian patients. CONCLUSIONS: The DOPPS results bring to light several positive aspects and the opportunity for further possible improvements for Italian patients, but at the same time highlight some critical points that could represent a risk for dialysis quality.

Acute effects of rapamycin on glomerular dynamics: a micropuncture study in the rat.

The acute effects of cyclosporin (CsA, 20 mg(kg i.v.) and rapamycin (RAPA, 5 mg(kg i.v.) on glomerular dynamics were separately investigated by renal micropuncture in two groups of intact rats (group CsA and RAPA, respectively) and compared with vehicle-treated rats, used as controls (group CON). Left kidney glomerular filtration rate (GFR) was decreased by CSA (-35% vs. CON, P<0.05), but was not affected by RAPA (-14% vs. CON, NS), whereas the single-nephron GFR (SNGFR) was significantly decreased in both groups (-40% in CsA, P<0.01 and -26% in RAPA, P<0.05 vs. CON). In both groups glomerular plasma flow (GPF) was significantly reduced vs. CON (CsA: -48%, and RAPA: -25%) due to the increase in both afferent (Ra) and efferent (Re) glomerular resistances: group CSA showed a prevalent rise in Re (+98% vs. CON, P<0.001) than in Ra (+66%, P<0.001); in group RAPA the increment was modest and similar in Ra and Re (+33 and +32%, respectively, NS versus CON). A further group of rats was studied in which L-Arginine (ARG), the precursor of nitric oxide (NO), was administered (2.5 mg/Kg/min iv) with RAPA (group ARG). ARG limited the rise in Ra and Re, thereby preserving GPF; nevertheless, SNGFR remained low (-26% vs. CON, P<0.05) due to the decrease in the effective filtration pressure (-26% vs. CON). These data demonstrate that: (1) CsA is nephrotoxic at immunosuppressive doses; (2) RAPA, even at huge doses, has marginal effects on renal and glomerular dynamics; (3) the ARG-NO pathway is only partially involved in the vasoconstriction of superficial nephrons after RAPA administration.

Current indications for renal biopsy: a questionnaire-based survey.

Indications for renal biopsy are still ill defined. We recently sent a detailed questionnaire to 360 nephrologists in different areas of the world with the aim of providing information on this critical issue by evaluating the replies. The questionnaire was organized in four sections that included questions on renal biopsy indications in patients with normal renal function, renal insufficiency, and a transplanted kidney. In addition, the questions included methods applied to each renal biopsy procedure and to specimen processing. We received 166 replies; North Europe (50 replies), South Europe (47 replies), North America (31 replies), Australia and New Zealand (24 replies), and other countries (14 replies). In patients with normal renal function, primary indications for renal biopsy were microhematuria associated with proteinuria, particularly greater than 1 g/d of protein. In chronic renal insufficiency, kidney dimension was the major parameter considered before renal biopsy, whereas the presence of diabetes or serological abnormalities was not considered critical. In the course of acute renal failure (ARF) of unknown origin, 20% of the respondents would perform renal biopsy in the early stages, 26% after 1 week of nonrecovery, and 40% after 4 weeks. In a transplanted kidney, the majority of nephrologists would perform a renal biopsy in the case of graft failure after surgery, ARF after initial good function, slow progressive deterioration of renal function, and onset of nephrotic proteinuria. The last section provided comprehensive information on the technical aspects of renal biopsy. This survey represents the first attempt to provide a reliable consensus that can be used in developing guidelines on the use of kidney biopsy.

Edema and acute renal failure.

Acute renal failure (ARF) with overhydration and edematous state may follow Acute endocapillary proliferative glomerulonephritis and extracapillary glomerulonephritis, because of reduction of the glomerular capillary area available for filtration. But ARF may also be observed in edematous patients with minimal change nephrotic syndrome; it may require dialysis until recovery and is attributable to some of the following factors: (1) ischemic renal injury, (2) hypovolemia, (3) interstitial edema with tubular collapse, (4) redistribution of renal blood flow (RBF) from cortical to juxtaglomerular nephrons, (5) decrease of capillary filtration coefficient (Kf), (6) use of nonsteroidal antiinflammatory drugs. Congestive heart failure also leads to prerenal azotemia and edema formation secondary to salt retention. Multiple organ dysfunction syndrome (MODS) is frequently associated with ARF; but edema occurs even without ARF in septic patients with severe inflammatory response syndrome (SIRS). ARF may follow severe burns; burned patients are frequently edematous because of a rapid leak of fluid from the vascular bed into the wound; edema in undamaged areas occurs in the 'flow phase', because of a fall of oncotic pressure because of massive loss of plasma proteins into the wound. Edema must be treated with diuretics or by dialysis.

Endothelin-1 released by vascular smooth muscle cells enhances vascular responsiveness of rat mesenteric arterial bed exposed to high perfusion flow.

Vasodilation of resistance vessels ensues in response to increased perfusion flow to maintain tissue perfusion. The flow-induced vasodilation is mainly dependent on nitric oxide (NO), which also regulates vascular responsiveness to vasoconstrictors. Besides NO, however; high flow increases endothelin-1 (ET-1) production from endothelial cells. It is likely, therefore, that the interaction between NO and ET-1 may play a critical role in the control of arterial vascular tone under high perfusion flow. In this study, the vascular responsiveness (VR) to high flow rate and the role of ET-1 released by vascular smooth muscle cells (VSMC) were evaluated in isolated and in vitro-perfused mesenteric arteries (MA). MA were perfused at constant (3.5 mL/min; CPF) and increased flow rate (4.5, 5.5, 6.5 mL/min; IPF). VR was evaluated by infusing norepinephrine (NE; 5 micromol/L) and potassium chloride (KCl; 80 mmol/L). Mesenteric vascular resistance (MVR), ET-1, and cGMP release were measured under different flow rates. The role of endothelium-derived ET-1 was evaluated by perfusing MA with phosphoramidon (endothelin converting enzyme inhibitor), whereas the role of other endothelium-derived vasoactive substances was excluded by measuring VR in MA without endothelium. Finally, ETA and ETB receptor antagonists were perfused in disendothelized MA. In the IPF group of intact MA, MVR dropped (P<.05) and both ET-1 and cGMP increased in the perfusate (P<.05). VR was enhanced by high flow after NE (101+/-9 v. 56+/-12 mm Hg in CPF, P<.005) and KCl (119+/-12 v. 51+/-10 mm Hg in CPF, P<.005) and it was unaffected by either phosphoramidon or endothelium removal. On the contrary, BQ-610 abolished the flow-dependent increase in VR. No further additive effect was achieved with BQ-788. In conclusion, in MA, high flow reduces MVR and concurrently enhances VR, likely through VSMC-derived ET-1.

The place of loop diuretics in the treatment of acute and chronic renal failure.

Loop diuretics (furosemide, bumetanide, muzolimine, piretamide, torasemide) are powerful drugs capable of increasing sodium excretion and urine output even when renal function is markedly impaired. In patients with chronic renal failure (CRF), loop diuretics may be given to control extracellular volume (ECV) expansion responsible for hypertension. But the use of loop diuretics in chronic uremia is mostly helpful when impaired renal function co-exists with nephrotic syndrome or chronic heart failure. Due to their powerful natriuretic activity, loop diuretics have been administered also to patients on maintenance dialysis to reduce the frequency of and/or to curtail dialysis time. In this condition, however, the increase of sodium and water excretion is very limited; whereas the use of diuretics in high dosage is not devoid of risky side effects such as neurologic lesions, cramps, deafness, weakness, muscle pain. In some patients with oliguric form of acute renal failure (ARF), loop diuretics increase sodium excretion and urine output. They do not affect the mortality rate for ARF but may facilitate the treatment of patients by reverting an oliguric form to a non-oliguric form of ARF.

Long-term follow-up of minoxidil therapy in refractory hypertension. A prospective trial in patients with various degrees of renal insufficiency.

Thirty patients with various degrees of renal insufficiency (4 on dialysis treatment) and severe hypertension refractory to conventional agents were treated with minoxidil and followed for up to 182 weeks. BP averaging 203 +/- 8.8/125 +/- 4.1 mm Hg supine and 194 +/- 7.8/125 +/- 3.9 upright before treatment, fell to 155 +/- 6.2/92 +/- 3.4 and 146 +/- 6.3/92 +/- 3.2 respectively within 1 week with 5 to 30 mg daily of minoxidil and remained stabilized around these normal values for three years or more. However, increasing doses of the drug became necessary after 52 weeks of therapy. Serum creatinine increased slightly during long-term treatment in most patients suggesting that the fall in renal function with time should be attributed to the natural progression of normotensive chronic renal failure. Adequate dialysis (in the 4 dialyzed patients) and high-ceiling diuretics prevented fluid imbalance during minoxidil therapy, while beta-blocking agents allowed complete control of reflex tachycardia.

Scleroembolization for treatment of hypertension caused by intrarenal arterial fibrodysplasia.

This paper reports a 13-year-old girl with severe hypertension due to fibrodysplasia of intrarenal arterial branches in the upper pole of the left kidney. Scleroembolization of the abnormal vascular region was carried out by injecting, via a transcutaneous catheter, an 80% solution of sodium iothalamate in ethanol, followed by a suspension of Gore-Tex particles in the same solution, which resulted in complete and persistent normalization of blood pressure.

Mechanism of impaired urinary concentrating ability in normokalemic primary aldosteronism.

Renal clearance studies were performed during anti-diuresis (before and after hypertonic saline infusion) and during water diuresis in three hypertensive patients with normokalemic primary aldosteronism (NPA) and in matched patients with normoreninemic essential hypertension (EH). The NPA patients showed an impaired ability to concentrate urine. By progressively increasing Cosm with saline loading, TcH2O plateaued both in NPA and in EH patients; in the former, however, the plateau occurred earlier and was lower than in the latter. In water diuresis, absolute values of CH2O were higher in NPA due to increased distal delivery secondary to impairment in proximal tubular reabsorption. Fractional CH2O (i.e. the ratio between CH2O and distal sodium delivery), however, was lower in NPA than in EH patients. Both in antidiuresis (after saline loading) and in water diuresis the NPA patients exhibited an enhanced fractional excretion of sodium. In one of NPA patients, clearance studies were repeated after adrenalectomy. In this patient, normalization of BP and reduction of body weight were associated with a rise in Uosm and a reduction in Cosm in antidiuresis; Uosm and Cosm were restored to pre-surgical values by expanding extracellular fluid volume (ECV) with saline loading. In summary our results suggest that ECV expansion is the mechanism by which urine concentration is impaired in patients with NPA.

Biological significance of the C3 nephritic factor in membranoproliferative glomerulonephritis.

Serum levels of the C3 nephritic factor (C3NeF), an IgG autoantibody directed against the C3bBb convertase of the alternative complement pathway, and of eight complement components (C1q, C4, C3, C3d, C5, C9, fB and properdin) were measured in 109 serum samples from 27 patients with idiopathic membranoproliferative glomerulonephritis (MPGN) (type I, 20 cases, and type II, 7 cases) and 14 patients with secondary MPGN. Correlations between the concentrations of C3NeF, serum complement levels and progression of the renal damage were studied during the course of the disease in 14 patients with C3NeF activity. The results showed that (1) C3NeF activity was more frequent in patients with type II MPGN than in patients with type I disease; nevertheless there was a high incidence of this splitting activity in patients with secondary MPGN, (2) high levels of the complement components were present in patients with MPGN, (3) low levels of C3 occurred frequently in type II disease and in secondary MPGN, (4) there was no correlation between C3, fB and C3NeF levels, (5) the presence of C3NeF was associated with a more rapid deterioration of renal function. Longitudinal studies showed that serum levels of C3NeF were not satisfactory for monitoring the clinical course of the illness and, in this respect, are similar to the levels of other autoantibodies in patients with autoimmune disease. As MPGN is a clinical syndrome with various pathogeneses, we suggest that the autoantibody, C3NeF, should be considered only as a marker of some forms of MPGN.

Total or partial percutaneous renal ablation in the treatment of renovascular hypertension: radiological and clinical aspects.

In 15 patients with renovascular hypertension, considered unsuitable for angioplasty or surgery, percutaneous renal ablation was performed by injection of ethanol into the renal vasculature. Partial or complete renal ablation was confirmed by follow-up intravenous pyelography or arteriography. Patients were followed-up for a mean of 24.8 months after therapy and blood pressure was improved in all patients with five being cured. This study shows that percutaneous renal ablation is a useful and successful method of therapy for renal hypertension, and that it should be considered in patients unsuitable for surgery or angioplasty.

Hemodialysis related interleukin-2 receptor release by peripheral blood mononuclear cells.

To evaluate the effects of hemodialysis treatment on the spontaneous cell release of interleukin-2 receptor (IL-2R), we studied 19 hemodialyzed patients (HD), 9 non hemodialyzed patients with chronic uremia (UR, glomerular filtration rate: 8.4 +/- 1.8 ml/min), and 8 healthy control subjects (C). We measured the release of IL-2R in the supernatant of peripheral blood mononuclear cells (PBMC) cultured for 24 hrs in Iscove's medium as well as the plasma levels of IL-2R. A significant increase of IL-2R release was detected in the supernatant of PBMC harvested from HD patients (32.4 +/- 2.4 and 34.2 +/- 5.6 U/3 x 10(6) PBMC daily before and after HD, respectively) as compared with UR (16.6 +/- 5.2 U/3 x 10(6) PBMC daily) and C (21.4 +/- 3.8 U/3 x 10(6) PBMC daily). Similarly, IL-2R plasma levels were significantly higher in HD (378.5 +/- 164.6 U/ml) than in UR (189.5 +/- 89.3 U/ml) and C (11.2 +/- 2.68 U/ml). To summarize, the current study demonstrates: a) an enhancement of spontaneous IL-2R cell release in HD patients; b) an increase of sIL-2R plasma levels in UR patients possibly related to reduced metabolism and/or urinary excretion, because it was not associated with high IL-2R cell release; and c) a further increment of IL-2R systemic levels in HD likely secondary to the high cell release of IL-2R. Therefore, a chronic T cell activation with increased release of IL-2R secondary to the dialysis procedure is suggested.

Membrane distillation of human plasma ultrafiltrate and its theoretical applications to haemodialysis techniques.

Membrane Distillation (MD) is a technique that allows the extraction of water from aqueous solutions. The basic principle is that vapour, but not liquid water, can pass through hydrophobic micro-porous membranes, along a temperature gradient, with consequent separation of water from solutes. In this study we evaluated the possibility to utilise MD to extract water from Plasma Ultrafiltrate (PU) of patients with Chronic Renal Failure (CRF). The experiments were carried out in vitro by a hydro-phobic polypropylene hollow-fibre distillation module; PU was obtained by a CRF patient utilising a high permeability polisulphone membrane. The results show that water can be extracted by MD from PU of CRF subjects at a constant rate and that none of the substances analysed in PU was able to pass through the polypropilene membrane. In the future MD could integrate extra-corporeal blood purification techniques allowing the re-utilisation of plasmatic water thus ameliorating the treatment of uraemia.

Concentration polarization phenomenon in new and re-used RP610 hemofilters during post-dilutional hemofiltration.

RP610 hemofilters have been used up to five times in post-dilutional hemofiltration. Clearance studies were performed "in vivo" (creatinine and phosphate) and "in vitro" (Cr51 EDTA, I131 Hypaque, Co57 vitamin B12, H3 Inulin, C14 Dextran, I125 Albumin,) in new hemofilters and in those re-used once and five times. Hydraulic permeability and rejection coefficients, for the six markers different molecular weight, were also measured. Our preliminary results show that repeated cleansing with Amuchina does not alter the characteristics of RP610 hemofilters. A scintigraphic method is suggested for visualizing possible changes in polarized areas between new and re-used hemofilters.

Is 3000 S Hospal a suitable dialyzer to shorten dialysis time schedule? A cooperative study on biofiltration.

The Biofilter 3000 S Hospal may combine higher convective clearance rates (Cc) with usual diffusive clearance rates (Cd) (i.e. similar to Cuprophan dialyzers), giving a higher total clearance rate (Ct) of small and middle molecules. Use of the Biofilter has been suggested to shorten dialysis time schedules. This study was carried out in 8 patients on RDT 3 times weekly, by cuprophan filter and acetate dialysis. The patients were shifted to dialysis with 3000 S guided by two principles: to shorten dialysis time by 1 hour per session, and to reinfuse 6 liters of bicarbonate-saline solution (40 mEq/l) per single dialysis. Besides the usual clinical and laboratory controls, in three patients clearance studies were carried out during four different dialysis sessions: Ct, Cc and Cd of urea K+, creatinine, uric acid and phosphate were measured. No change was observed in the main clinical and laboratory parameters after 3-5 months (average 3.9) of treatment with Biofilter 3000 S; in addition, serum alkaline phosphatase concentration decreased progressively. Clearance results, however, indicate that the expected high values of Ct do not occur, because Cd decreases as Cc is increased. A primary goal of research in hemodialysis is to reduce the average time of treatment while ensuring simultaneously "physiological" dialysis. A possible approach to this problem is to use dialyzers with highly permeable and biocompatible membranes such as the "biofilter" 3000 S Hospal.(ABSTRACT TRUNCATED AT 250 WORDS)

[Relations of gingival hypertrophy and blood levels of cyclosporin A in patients with renal transplants]. / Relazione tra ipertrofia gengivale e livelli ematici di ciclosporina A nei pazienti con trapianto renale.

Gingival overgrowth is defined as hyperplasia of gingival tissue due to local, systemic or drug-related causes. To see if the incidence and severity of this side-effect are related to cyclosporine A (CyA) dosage and/or blood levels BCyA), we analysed data from 24 renal transplanted outpatients, grouped as follows: controls (C, n = 3): patients on immunosuppressive therapy other than CyA; group 1 (G1, n = 10): patients with BCyA steadily 300 ng/mL (RIA); group 2 (G2, n = 11): patients with BCyA steadily between 301 and 650 ng/mL. BCyA averaged 290 +/- 21 in G1 and 481 +/- 100 in G2 (p less than 0.001): mean cyclosporine A dosage (mg/kg/die) was not significantly different: 4.1 +/- 1.4 in G1 and 4.97 +/- 2.4 in G2. However, six patients in G2 also received calcium antagonists known to increase CyA blood levels (diltiazem and nicardipine) for clinical purposes or deliberately to increase CyA bioavailability. Mean time from transplant was (in months) 19 +/- 11 in G1, 16 +/- 15 in G2 and 62 +/- 24 in C (G1 vs G2: NS; C vs G1 and 2: p less than 0.001). Mean GFR (mL/min) was 75 +/- 22 in C, 65 +/- 18 in G1 and 53 +/- 19 in G2 (NS). Dental hygiene, as assessed by scoring (0-3: absent, mild, moderate and severe) the bacterial plaque, was similar in all groups. Gingival overgrowth, was similarly scored (0-3) and was absent in C and in 20% of G1, mild in 40% of G1 and 33% of G2, moderate in 40% of G1 and 33% of G2 and severe in 0% of G1 and 33% of G2 (G1 vs G2: p less than 0.05). Our data suggest that the severity of gingival overgrowth in transplanted patients with similar oral hygiene is mainly related to CyA blood levels.