Risk of end-stage kidney disease in kidney transplant recipients versus patients with native chronic kidney disease: multicentre unmatched and propensity-score matched analyses

BACKGROUND

In kidney transplant recipients (KTR), the end-stage kidney disease (ESKD) risk dependent on the risk factors acting in native chronic kidney disease (CKD) remains undefined.

METHODS

We compared risk and determinants of ESKD between 757 adult KTR and 1940 patients with native CKD before and after propensity-score (PS) analysis matched for unmodifiable risk factors [(age, sex, diabetes, cardiovascular disease and estimated glomerular filtration rate (eGFR)].

RESULTS

In unmatched cohorts, eGFR was lower in CKD versus KTR (45.9 ± 11.3 versus 59.2 ± 13.4 mL/min/1.73 m2, P < 0.001). During a median follow-up of 5.4 years, the unadjusted cumulative incidence of ESKD was consistently lower in unmatched KTR versus CKD. Conversely, in PS-matched analysis, the risk of ESKD in KTR was 78% lower versus CKD at 1 year of follow-up while progressively increased over time resulting similar to that of native CKD patients after 5 years and 2.3-fold higher than that observed in CKD at 10 years. R2 analysis in unmatched patients showed that the proportion of the outcome variance explained by traditional ESKD determinants was smaller in KTR versus native CKD (31% versus 70%). After PS matching, the risk of ESKD [hazard ratio (HR), 95% confidence interval (95% CI)] was significantly associated with systolic blood pressure (1.02, 1.01-1.02), phosphorus (1.31, 1.05-1.64), 24-h proteinuria (1.11, 1.05-1.17) and haemoglobin (0.85, 0.78-0.93) irrespective of KTR status. Similar data were obtained after matching also for modifiable risk factors.

CONCLUSIONS

In KTR, when compared with matched native CKD patients, the risk of ESKD is lower in the first 5 years and higher later on. Traditional determinants of ESKD account for one-third of the variability of time-to-graft failure.

[Ultrasonography in chronic lithium nephropathy: a case report]

Lithium has always been used as a first-choice therapy in bipolar disorders. However, its therapeutic index is restricted by placing patients at risk of potential nephrotoxic effects ranging from polyuria, to Insipid Nephrogenic Diabetes, to chronic kidney disease with a slow reduction of renal function over time. The Nephrologist has the role to diagnose chronic lithium nephropathy, monitoring its evolution and optimizing the management of risks associated with the treatment. In fact, the main objective, to be shared with the psychiatrist, is to encourage the maintenance of therapy even in the presence of nephropathy. Renal ultrasound, a safe, repeatable and low-cost technique, is essential to pursue this goal as it not only confirms the diagnosis of chronic lithium nephropathy hypothesized on the basis of the history and clinical picture, but is also helpful in monitoring its evolution. In this paper, we report a case of chronic lithium nephropathy in order to analyze the etiopathogenesis of renal damage, the clinical-laboratory and histological picture and, in particular, the fundamental role of ultrasound imaging.

Competing-Risk Analysis of Death and End Stage Kidney Disease by Hyperkalaemia Status in Non-Dialysis Chronic Kidney Disease Patients Receiving Stable Nephrology Care

Hyperkalaemia burden in non-dialysis chronic kidney disease (CKD) under nephrology care is undefined. We prospectively followed 2443 patients with two visits (referral and control with 12-month interval) in 46 nephrology clinics. Patients were stratified in four categories of hyperkalaemia (serum potassium, sK ≥ 5.0 mEq/L) by sK at visit 1 and 2: Absent (no-no), Resolving (yes-no), New Onset (no-yes), Persistent (yes-yes). We assessed competing risks of end stage kidney disease (ESKD) and death after visit 2. Age was 65 ± 15 years, eGFR 35 ± 17 mL/min/1.73 m², proteinuria 0.40 (0.14–1.21) g/24 h. In the two visits sK was 4.8 ± 0.6 and levels ≥6 mEq/L were observed in 4%. Hyperkalaemia was absent in 46%, resolving 17%, new onset 15% and persistent 22%. Renin-angiotensin-system inhibitors (RASI) were prescribed in 79% patients. During 3.6-year follow-up, 567 patients reached ESKD and 349 died. Multivariable competing risk analysis (sub-hazard ratio-sHR, 95% Confidence Interval-CI) evidenced that new onset (sHR 1.34, 95% CI 1.05–1.72) and persistent (sHR 1.27, 95% CI 1.02–1.58) hyperkalaemia predicted higher ESKD risk versus absent, independently from main determinants of outcome including eGFR change. Conversely, no effect on mortality was observed. Results were confirmed by testing sK as continuous variable. Therefore, in CKD under nephrology care, mild-to-moderate hyperkalaemia status is common (37%) and predicts per se higher ESKD risk but not mortality.

[Anti-diabetics and chronic kidney disease]

Diabetes mellitus (DM) is the most important non-communicable disease after hypertension. Prevalence of type 2 DM has progressively increased over the last decades. In Italy, 11.8% of the general adult population can be identified as diabetic. The major complication of DM is diabetic nephropathy (DM-CKD), which develops in approximately one-third of diabetics. Achieving optimal glycemic control is the first therapeutic goal in the management of DM-CKD. In recent years, new antidiabetic drugs have been marketed (GLP1 analogues, DPP-4 inhibitors, SGLT-2 inhibitors) to ameliorate glycemia in patients nave or treated by means of traditional agents, such as sulfonylureas, metformin, glinides, insulin. However, use of these drugs in DM-CKD should be evaluated carefully, mainly because of the higher risk of hypoglycemia that requires dosing adjustments. Metformin still represents an adequate choice if proper dose adjustments are made on the basis of renal function. Sulfonylureas with limited renal clearance, i.e., gliquidone, glipizide and gliclazide are an alternative to metformin and more effective than repaglinide on glycemic control. Other antidiabetic agents with potential nephroprotective effects, namely DPP-4 inhibitors, incretin analogues and SGLT-2 inhibitors, may allow nephroprotective effects independent of glycemic control. Insulin remains the cornerstone of therapy when oral therapy is no longer effective.

Phytomorphological and essential-oil characterization in situ and ex situ of wild biotypes of oregano collected in the Campania region (Southern Italy)

Oregano is an aromatic species of great interest, which spreads spontaneously over the Mediterranean area, but its genetic resources are not yet adequately developed. Moreover, the results of studies of wild strains of different origin - although quite numerous - are not always comparable, and, therefore, the influence of the environment and genotype on the variability cannot be distinguished. Hence, the plant morphology and the essential-oil composition of three wild, white-flowering biotypes of oregano collected in the Campania region (southern Italy) were characterized, and the effects of genotype and environment were assessed by comparison in situ and ex situ. This allowed deducing that the biotypes belonged to two different subspecies, i.e., Origanum vulgare ssp. virens and O. vulgare ssp. viridulum. The essential-oil yield was higher for the biotype belonging to ssp. virens, and it was significantly correlated with the glandular and stomatal density. The chemical composition of the oils obtained by hydrodistillation was found to be influenced by the genotype and the conditions of plant growth.

Renin-angiotensin system inhibitors reduce the progression of mesangioproliferative glomerulonephritis: 10 year follow-up

BACKGROUND

Proteinuria is a common presentation of mesangioproliferative glomerulonephritis (MsPGN). No studies are available on the long-term effect of treatment by renin-angiotensin system (RAS) inhibitors on renal outcome in MsPGN patients. This study prospectively evaluates the effects of RAS inhibitors on renal outcome in patients with low risk MsPGN followed up for 10 years using historical patients with similar features at the time of presentation as untreated controls.

ENDPOINTS

decrease of basal proteinuria>20% and loss>20% of basal glomerular filtrate rate (GFR) at the end of first year of observation. The patients were re-evaluated bimonthly during the first year and every 6 months thereafter.

RESULTS

Twenty-five patients fulfilled the selection criteria. After one year follow-up 19 patients reached the endpoint of proteinuria and no patient reached the endpoint of GFR. No significant change in blood pressure levels (BP) and GFR was registered, by contrast daily proteinuria decreased significantly (p<0.001), falling by 29% at sixth month and 47% at the end of the follow-up. The historical control group consisted of 15 untreated patients seen between 1987 and 1992. The two-way analysis of variance for repeated measures showed greater values of GFR (p<0.001) and lower levels of daily proteinuria (p<0.001) in treated patients as compared to untreated controls.

CONCLUSIONS

This 10-year follow-up study indicates that the early treatment with RAS inhibitors at low doses favourably influences the long-term renal outcome in proteinuric patients with MsPGN. Limitations were the small sample size and lack of randomization.

[Hyponatremia secondary to inappropriate antidiuretic hormone secretion]

The syndrome of inappropriate antidiuretic hormone secretion (SIADH) is a disorder of sodium and water balance characterized by hypotonic hyponatremia and impaired water excretion in the absence of renal insufficiency , adrenal insufficiency or any recognized stimulus for the antidiuretic hormone (ADH). An inappropriate increase in ADH release of any cause produces hyponatremia by interfering with urinary dilution, thereby preventing the excretion of ingested water. Despite being the most common cause of hyponatremia in hospitalized patients, SIADH remains a diagnosis of exclusion. SIADH should be suspected in any patient with hyponatremia, hyposmolarity, urine osmolality above 100 mosmol/hgH2O, urine sodium concentration usually above 40 mEq/L, and clinical euvolemia. a number of modalities can be used to correct hyponatremia in SIADH, with water restriction and salt administration being the most important. The rate of correction is dependent upon the degree of hyponatremia and the presence or absence of symptoms. Patients with severe neurological symptoms require prompt correction; however, excessively rapid correction should be avoided because it can lead to the late onset of neurological complications from osmotic demyelination.

Mesangial hypercellularity predicts antiproteinuric response to dual blockade of RAS in primary glomerulonephritis

The greater antiproteinuric efficacy of converting enzyme inhibitor and angiotensin II receptor blocker combination (CEI+ARB), versus monotherapy with either drug, is not a consistent finding. We evaluated the clinicopathologic predictors of response to CEI+ARB in 43 patients with primary glomerulonephritis (GN), never treated with immunosuppressive drugs, and with persistent proteinuria after CEI alone. Main histological lesions were analyzed by obtaining on 557 glomeruli and 165 arteries formal score of mesangial cellularity, glomerulosclerosis, tubulointerstitial damage, mononuclear cell infiltration, arteriosclerosis, and arteriolar hyalinosis. Duration of CEI and CEI+ARB therapy was similar (4.7+/-2.4 and 5.0+/-1.5 months). Proteinuria (g/day) decreased from 3.5+/-2.9 to 2.4+/-2.3 after CEI, and to 1.5+/-1.3 after CEI+ARB (P<0.0001). Reduction of proteinuria after CEI+ARB was greater in proliferative versus non-proliferative GN (-63.3+/-23.4 versus 42.4+/-23.7%, respectively; P=0.006). When patients were categorized in responders and non-responders to CEI+ARB, no difference between the two groups was detected in any demographic or clinical variable, whereas histology showed in responders a greater prevalence of proliferative GN (71.4 versus 31.8%, P=0.009) and higher score of mesangial cellularity (1.76+/-0.53 versus 1.20+/-0.22, P<0.0001). At multiple regression analysis (r(2)=0.476, P=0.001), response to CEI+ARB resulted independently related only to mesangial cellularity (P<0.0001). In conclusion, the best independent predictor of antiproteinuric efficacy of CEI+ARB in patients with primary GN is the degree of mesangial cellularity. This finding supports the experimental evidence that high angiotensin II contributes to proliferation of mesangial cells.

Supplemented very low protein diet ameliorates responsiveness to erythropoietin in chronic renal failure

BACKGROUND

The aim of this study was to evaluate the relationship between uremic state and erythropoiesis in patients with predialytic chronic renal failure (CRF).

METHODS

We monitored for 2 years the erythropoietin (EPO) requirement in patients with advanced CRF (creatinine clearance < or =25 mL/min), randomized to either low protein diet (LPD) group (0.6 g/kg body weight/day, N = 10) or very low protein diet (VLPD) group (0.3 g/kg body weight/day, N = 10) supplemented with a mixture of ketoanalogs and essential amino acids, both kept at target hemoglobin levels.

RESULTS

The achieved protein intake after 6 months was 0.79 +/- 0.02 g/kg body weight/day and 0.50 +/- 0.02 g/kg body weight/day in LPD and VLPD, respectively; such a difference was maintained up to the end of follow up. The final hemoglobin values did not differ from the basal values in either group (11.5 +/- 0.2 g/dL and 11.5 +/- 0.3 g/dL). EPO dose, that was similar at baseline (62.4 +/- 9.6 UI/kg body weight/week and 61.8 +/- 8.8 UI/kg body weight/week subcutaneously), remained unchanged in LPD but progressively decreased in VLPD down to the final value of 41.2 +/- 7.0 UI/kg body weight/week (P < 0.0001 vs. basal and LPD). VLPD was associated with a decrease of urinary excretion and serum levels of urea nitrogen and phosphate; however, EPO requirement was not correlated with the changes of these parameters. On the contrary, the variation of EPO dose directly correlated with the modification of parathyroid hormone (PTH) levels, that diminished from 229 +/- 55 pg/mL to 118 +/- 16 pg/mL (P < 0.0001) in VLPD and did not change in LPD.

CONCLUSION

In patients with advanced CRF, an effective decrease of protein intake of 0.3 g/kg body weight/day induces a reduction of about 35% of the EPO dose required to maintain the target hemoglobin levels. This effect appears dependent on the correction of a moderate secondary hyperparathyroidism.

Intra- and post-dialytic changes of haemoglobin concentrations in non-anaemic haemodialysis patients

BACKGROUND

Non-anaemic haemodialysis (HD) patients are potentially more prone to the adverse effects of ultrafiltration-induced haemoconcentration. No study, however, has assessed the effects of dialytic session on haemoglobin (Hb) levels in these patients.

METHODS

The levels of Hb and total protein before, at the end (T0) and up to 120 min (T120) after the third HD session of the week were compared in non-anaemic (Hb >13 g/dl, n = 14, NOR) and anaemic (Hb = 11-12 g/dl, n = 18, LOW) HD patients.

RESULTS

The intradialytic weight loss was similar in the two groups (4.0 +/- 0.9 and 4.1 +/- 0.9% body weight). During the treatment, Hb levels increased to the same extent in both groups (from 14.4 +/- 1.2 to 16.3 +/- 1.9 g/dl in NOR, and from 11.4 +/- 0.8 to 12.7 +/- 0.9 g/dl in LOW) in the presence, presumably, of a smaller plasma volume in NOR, whereas the increment of total protein was greater in NOR (from 7.1 +/- 0.2 to 9.6 +/- 0.5 g/dl) than in LOW (from 7.3 +/- 0.6 to 8.7 +/- 0.8 g/dl) (P < 0.0001). At T120, the Hb decline in NOR was almost double that measured in LOW (-9.2 +/- 3.0 vs -4.7 +/- 2.4%, P < 0.001). Consequently, Hb concentration did not differ from the pre-dialytic value in NOR (P = 0.10), but persisted higher in LOW (P < 0.005). The extent of the post-dialytic decrement of Hb was inversely related to the total protein values at T0 (r = -0.547, P = 0.0012).

CONCLUSIONS

This study indicates that in NOR: (i) the extent of intradialytic increment of Hb is limited by a greater intradialytic plasma refilling; (ii) the greater plasma refilling persists after the end of dialysis, with the restoration of pre-dialytic Hb levels within the initial 2 h; and (iii) the force driving this phenomenon resides mainly in the larger changes of total protein concentration.

[Daily nutrient intake in hemodialysis]

BACKGROUND

Although there is a higher nutrient requirement, food intake in haemodialysis patients is often inadequate. Protein nitrogen appearance (PNA) indirectly estimates the mean protein intake during the short interdialysis period, but it does not measure the daily nutrient intake, which is generally unknown. We carried out a longitudinal study aimed at estimating the daily nutrient intake and its relationship with the nutritional status of haemodialysis patients.

METHODS

We selected 28 haemodialysis patients with adequate nutritional status and no evidence of risk-factor for malnutrition. Patients were treated with biocompatible membranes, low-flux and high bicarbonate dialysis, Kt/V > 1.2, PNA > 1.1 g/kg/day and erythropoietin. We measured every four months daily PNA, protein and calorie intake (DPI, DCI) as well as weight gain (WG) during an entire week for one-year. The nutritional status was assessed by biochemical and BIA markers.

RESULTS

Twenty seven subjects (8 F, 19 M; age 57.1 +- 2.7 yeas; dialysis age 105 +- 13 months) completed the trial. The mean interdialytic PNA did not change in both long- and short-interdialysis periods, resulting in the "normal" range (> 1.1 g/kg/day); however, daily levels of protein and calorie intake were significantly reduced on the third day during the long interdialysis interval. Eight patients showed time-averaged values of DPI and DCI lower than 0.8 g/kg/day and 25 Kcal/kg/day, respectively, on the third day (LOW group), values that were associated with similar changes in WG. Such a highly reduced nutrient intake during the third interdialysis day was associated with a normal PNA value (1.23 +- 0.05 g/kg/day vs 1.30 +- 0.06 in CON, NS) when measured during the short interdialysis period (S), just as it is in clinical practice; in contrast, when the PNA value was measured during the long interdialysis period it was found to be significantly reduced (1.07 +- 0.08 g/kg/day vs 1.37 +- 0.06 in CON, p < 0.05 and vs S, p < 0.05). During the study, the body weight progressively decreased from 68.0 +- 5.5 to 65.8 +- 5.9 kg (p < 0.05) in the LOW group, due to the decrease in lean body mass, as suggested by the reduction in serum creatinine (9.2 +- 1.1 vs 8.1 +- 0.7 mg/dL, p < 0.05), creatinine generation (835 +- 155 vs 723 +- 106 mg/die, p < 0.05) and serum albumin (3.96 +- 0.07 vs 3.66 +- 0.06 g/dL, p < 0.05). Moreover, reactance and phase angle declined in the LOW group (from 54 +- 4 to 44 +- 3 ohms, p < 0.05 and 5.5 +- 0.3 to 4.5 +- 0.3 degrees, p < 0.05, respectively). At the end of the study the nutritional status in the LOW group was reduced as compared to the CON group.

CONCLUSIONS

In stable, well-nourished haemodialysis patients, in absence of known risk factors for malnutrition, the daily nutrient intake is variable and progressively reduce during the interdialytic interval. The measurement of interdialytic PNA, as is done in clinical practice, does not enable the discovery of such abnormal eating behaviour; the low daily nutrient intake, on the contrary, can be evidenced by the daily measurement of either PNA or weight gain, and it can also be inferred by the reduced PNA during the long interdialytic period. Finally, the persistent reduction in nutrient intake below the threshold of 0.8 g/kg/day of proteins and 25 Kcal/kg/day one day a week, is capable of inducing body protein wasting and moderate impairment of the nutritional status.

Daily nutrient intake represents a modifiable determinant of nutritional status in chronic haemodialysis patients

BACKGROUND

In maintenance haemodialysis patients, daily food intake is changeable; however, its relationship with nutritional status is unexplored. This study aimed to evaluate the isolated, long-term effect of daily nutrient intake on nutritional status in haemodialysis patients.

METHODS

We performed a prospective 1-year controlled study in 27 chronic haemodialysis patients, without recognized risk factors for malnutrition. Each day for 1 week, four times in the year, we measured protein nitrogen appearance, and assessed dietary protein (DPI) and energy (DEI) intake from dietary diaries. We compared the nutritional outcome of patients spontaneously reducing nutrient intake below the threshold of 0.8 g/kg body weight/day for DPI and 25 kcal/kg body weight/day for DEI during the week (LOW, n = 8), with controls at adequate nutrient intake (CON, n = 19). An interventional 6-month study was then carried out in LOW to verify the cause-effect relationship.

RESULTS

All patients showed a day-by-day reduction of whole nutrient intake during interdialytic period, which was mostly relevant in the third interdialytic day (L3). During the 1-year study, even in the presence of adequate dialysis dose and normal inflammatory indexes, body weight (68.0 +/- 5.5 to 65.8 +/- 5.9 kg), serum albumin (3.96 +/- 0.07 to 3.66 +/- 0.06 g/dl) and creatinine (9.2 +/- 1.1 to 8.1 +/- 0.7 mg/dl) significantly decreased in LOW but not in CON. Diaries evidenced in LOW a reduced number of meals at L3 that was explained by the fear of excessive interdialytic weight gain. During the interventional study, daily DPI and DEI increased at L3; this was associated with a significant increment of body weight, and serum albumin and creatinine levels.

CONCLUSIONS

In maintenance haemodialysis patients the persistent, marked reduction of daily nutrient intake, even if limited to a single day of the week, is an independent determinant of reversible impairment of nutritional status.

Maximal suppression of renin-angiotensin system in nonproliferative glomerulonephritis

BACKGROUND

Elimination of residual proteinuria is the novel target in renoprotection; nevertheless, whether a greater suppression of renin-angiotensin system (RAS) effectively improves the antiproteinuric response in patients with moderate proteinuria remains ill-defined.

METHODS

We evaluated the effects of maximizing RAS suppression on quantitative and qualitative proteinuria in ten patients with stable nonnephrotic proteinuria (2.55 +/- 0.94 g/24 hours) due to primary nonproliferative glomerulonephritis (NPGN), and normal values of creatinine clearance (103 +/- 17 mL/min). The study was divided in three consecutive phases: (1) four subsequent 1-month periods of ramipril at the dose of 2.5, 5.0, 10, and 20 mg/day; (2) 2 months of ramipril 20 mg/day + irbesartan 300 mg/day; and (3) 2 months of irbesartan 300 mg/day alone.

RESULTS

Maximizing RAS suppression was not coupled with any major effect on renal function and blood pressure; conversely, a significant decrement in hemoglobin levels, of 0.8 g/dL on average, was observed during up-titration of ramipril dose. The 2.5 mg dose of ramipril significantly decreased proteinuria by 29%. Similar changes were detected after irbesartan alone (-28%). The antiproteinuric effect was not improved either by the higher ramipril doses (-30% after the 20 mg dose) or after combined treatment (-33%). The reduction of proteinuria led to amelioration of the markers of tubular damage, as testified by the significant decrement of alpha 1 microglobulin (alpha 1m) excretion and of the tubular component of proteinuria at sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE).

CONCLUSION

In nonnephrotic NPGN patients, standard doses of either ramipril or irbesartan lead to significant reduction of residual proteinuria and amelioration of the qualitative features suggestive of tubular damage. The enhancement of RAS suppression up to the maximal degree does not improve the antiproteinuric response and is coupled with a decrement of hemoglobin levels.

Influence of the cyclic variation of hydration status on hemoglobin levels in hemodialysis patients

BACKGROUND

Maintenance hemodialysis (HD) patients were studied to assess the effect on hemoglobin (Hb) concentration induced by the cyclic variation in hydration status.

METHODS

Forty-nine HD patients were examined in three consecutive HD sessions in a 1-week treatment period. In a subgroup of 23 patients, Hb levels also were investigated during the long interdialytic interval.

RESULTS

Hb levels at the end of the long interdialytic interval were significantly lower by 0.5 to 0.6 g/dL (5 to 6 g/L) than those at the end of short intervals. Among all pre-HD and post-HD Hb values, levels measured at the end of short intervals were closest to the mean Hb value of the week, derived from calculation of the area under the curve (12.0 +/- 0.2 g/dL [120 +/- 2 g/L]). Intradialytic Hb increments were different in the three sessions (+1.6 +/- 0.1 g/dL [+16 +/- 1 g/L] after the long interval, +1.1 +/- 0.1 g/dL [+11 +/- 1 g/L] and +1.1 +/- 0.1 g/dL [+11 +/- 1 g/L] after short intervals [P < 0.001] and proportionate to weight loss [-3.4 +/- 0.1, -2.7 +/- 0.1, and -2.6 +/- 0.1 kg, respectively; P < 0.001]). Hb level increment and weight loss correlated directly (r = 0.527; P < 0.0001); each 1 L of ultrafiltration (UF) led to an increase in Hb level of approximately 0.4 g/dL (4 g/L). Plasma refilling accounted for an approximately 45% decrement in the intradialytic increase in Hb level 2 hours post-HD.

CONCLUSION

This study suggests that: (1) the end of the short interdialytic period is the most appropriate timing for anemia assessment, and (2) the remarkable hemodiluting effect of post-HD plasma refilling protects against excessive increments in Hb levels induced by UF.

Postdialytic rebound of serum phosphorus: pathogenetic and clinical insights

To gain insights into postdialytic rebound of serum phosphate (PDR-P), serum phosphate (P), calcium (Ca), and parathyroid hormone (PTH), levels were compared from the end of treatment (T0) to the subsequent 30 to 120 min and up to 68 hr in uremic patients who underwent with crossover modality a single session of two dialytic treatments characterized by different convective removal: standard hemodialysis (HD) and hemodiafiltration (HDF). In HDF, versus HD, P removal was greater (1171 +/- 90 versus 814 +/- 79 mg; P < 0.05) in the presence of similar predialytic P levels (6.0 +/- 0.2 and 5.9 +/- 0.4 mg/dl) and Kt/V (1.35 +/- 0.06 and 1.34 +/- 0.05); however, the serum P values at T0 did not differ (3.0 +/- 0.2 versus 3.3 +/- 0.2 mg/dl). In HDF, PDR-P was more rapid (30 min versus 90 min) and of a greater extent (at T120: +69 +/- 6% versus +31 +/- 4%; P < 0.0001). The higher P levels were maintained throughout the interdialytic period. Ca x P and PTH changed in parallel. Thereafter, patients were randomized to receive either HD or HDF for 3 mo. During this period, in the presence of similar Kt/V, protein intake, and dose of phospate binder, predialytic serum P levels diminished in HDF (from 5.8 +/- 0.2 to 4.4 +/- 0.3 mg/dl; P < 0.05), but they remained unchanged in HD. A similar pattern of changes was detected in Ca x P. Therefore, PDR-P is likely dependent on the mobilization of phosphate from a deep compartment induced by the intradialytic removal of this solute. Enhancement of convective removal acutely amplifies the entity of the phenomenon but allows a better control of Ca-P homeostasis in the medium term.

Storage in the yolk platelets of low MW DNA produced by the regressing follicle cells

The present work was carried out to clarify the nature and origin of the yolk DNA present in vitellogenic oocytes of the lizard Podarcis sicula. Morphological and biochemical evidences indicate that it has an intrafollicular origin, from the apoptotic bodies resulting from follicle cells regression at the end of previtellogenesis. This conclusion is reinforced by the observation that the oocyte membrane, in in vitro experiments, is unpermeable to exogenous DNA. Biochemical evidences reveal that the yolk DNA has a low (200bp) molecular weight and this suggests that it is produced by the endonucleases typically involved in apoptotic DNA laddering. Indeed, immunocytochemical analyses demonstrate that follicle cells contain significant amounts of DNAse I. In immunoblots, carried out during different periods of the ovarian cycle, the enzyme shows a MW of about 33, 66 or 100 kDa thus indicating that its activity in the follicle of Podarcis is modulated by dimerization and/or binding to regulatory factors. Mol. Reprod. Dev. 59: 422-430, 2001.

Control of oocyte recruitment: regulative role of follicle cells through the release of a diffusible factor

To determine whether oogonial proliferation and oocyte recruitment are under control of hypophyseal and/or ovarian factors, we carried out a series of investigations using Podarcis sicula, a lizard inhabiting the temperate lowlands of Europe in which oocyte recruitment occurs throughout the year, as animal model. Germinal beds containing oogonia and oocytes in prefollicular stages were cocultured with different ovarian compartments in presence/absence of FSH, and the effects of different treatments were evaluated by counting the number of prelepto-leptotene oocytes. Results revealed that oocyte recruitment from the pool of oogonia is under the control of a factor released by follicle cells while FSH has an indirect effect on modulating oogonial proliferation. SDS-PAGE analyses carried out on media conditioned by follicles suggest that the factor involved in the control of oocyte recruitment may be a small protein (about 21 kDa) and that its release is dependent on the period of the ovarian cycle but apparently not on the circulating levels of FSH.

Abnormalities of bioimpedance measures in overweight and obese hemodialyzed patients

BACKGROUND

The body composition in overweight and obese hemodialyzed patients (HD) remains ill-defined. This study evaluates in HD patients the influence of body size, as indicated by body mass index (BMI, kg/m(2)), on body composition by measuring bioimpedance analysis (BIA)-derived variables (phase angle (PA), fat-free mass (FFM) and body cell mass (BCM).

METHODS

We studied 50 Caucasian patients (mean age 62.8+/-9.2 y) on standard bicarbonate hemodialysis for at least 12 months who regularly achieved dry weight in post-HD, received similar dialysis doses and were free from inflammation/infection. Thirty-eight gender- and age-matched healthy subjects were included as controls (CON). Both HD and CON were divided into three groups on the basis of their BMI(kg/m2) 18.5-24.9, normal-weight (NW); 25-29.9, overweight (OW); and > or =30, obese (OB). In HD patients, BIA was performed 30 min after the end of dialysis.

RESULTS

Seven patients were obese (12%) while 16 were overweight (32%); in CON, 12 were obese (31%) and 12 overweight (31%). BIA-measured extracellular water was comparable in all groups. PA, which was similar in normal-weight HD and CON (6.2+/-0.9 degrees and 6.3+/-0.8 degrees ), decreased in OW- and OB-HD patients (5.3+/-1.0 degrees and 5.2+/-0.6 degrees, respectively; P<0.05 vs NW-HD) while it was unchanged in OW- and OB-CON (6.1+/-0.8 degrees and 5.9+/-0.5 degrees, P<0.05 vs respective HD groups). In OW and OB patients, the lower PA values were coupled with a major reduction of BIA-derived percentage BCM and FFM (P<0.05 vs NW-HD, and vs OW- and OB-CON). In patients, PA and BCM correlated with anthropometry-measured FFM. Of note, serum albumin and protein catabolic rate were significantly reduced in OB patients.

CONCLUSION

In overweight and obese HD patients, BIA-derived FFM, BCM and PA are significantly lower with respect to normal-weight patients and BMI-matched controls. These abnormalities of body composition are coupled with reduction of anthropometric measures of lean mass and a decrease of protein intake that, however, becomes significant only in the obese. We therefore suggest that overweight and obese HD patients are at risk of protein malnutrition in spite of excessive energy intake. BIA may be considered as a useful diagnostic tool to detect such a condition early.

Effect of dialysate sodium concentration on interdialytic increase of potassium

To evaluate the role of plasma tonicity in the postdialysis increment of plasma potassium (p[K(+)]), the outcome of two hemodiafiltration treatments that differed only in the Na(+) level in dialysate (Na(D))-143 mmol/L (high dialysate sodium concentration [H-Na(D)]) and 138 mmol/L (low dialysate sodium concentration [L-Na(D)])-were compared in the same group of uremic patients from the end of treatment (T0) to the subsequent 30 to 120 min and up to 68 h. Kt/V and intradialytic K(+) removal were comparable. At T0, plasma [Na(+)] was 145+/-1 and 137+/-1 mmol/L after H-Na(D) and L-Na(D), respectively (P<0.001). The difference in plasma tonicity persisted from T0 to T68 h. At T120, p[K(+)] was increased from the T0 value of 3.7+/-0.2 to 4.7+/-0.2 mmol/L (P<0.05) after H-Na(D), whereas it was unchanged after L-Na(D). The change of p[K(+)] was still different after 68 h (+76+/-10% and +50+/-7% in H-Na(D) and L-Na(D), respectively; P<0.05). Of note, in the first 2 h after the end of treatment, bioimpedance analysis revealed only in H-Na(D) a significant 11+/-3% decrement of phase angle that is compatible with a decrease of intracellular fluid volume at the expense of the extracellular volume. Similarly, within the same time frame, in H-Na(D), a significant reduction of mean corpuscular volume of red cells, associated with a 2 +/-1% decrease of the intracellular [K(+)], was observed. In contrast, mean corpuscular volume of red cells did not change and erythrocyte [K(+)] increased by 6+/-1% after L-Na(D) (P<0.005 versus H-Na(D)). Thus, hypertonicity significantly contributes to the increase of p[K(+)] throughout the whole interdialytic period by determining intracellular fluid volume/extracellular volume redistribution of water and K(+).

Triterpene saponins and iridoid glucosides from galium rivale

Three new glycosides of the oleanene-type triterpenes, rivalosides C-E (1-3), along with three known triterpene saponins, momordin IIb (4) and rivalosides A-B (5-6), and five known iridoid glucosides: monotropein, scandoside, deacetylasperulosidic acid, geniposidic acid and asperulosidic acid, were isolated from aerial parts of Galium rivale. The structures of the new compounds were elucidated by spectral methods and chemical means as 2alpha-acetoxy-3alpha, 19alpha-dihydroxy-olean-12-en-28-oic acid 28-O-beta-D-glucopyranosyl-(1--> 6)-beta-D-glucopyranoside, 2alpha,3alpha, 19alpha-trihydroxy-olean- 12-en-28-oic acid 28-O-beta-D-glucopyranosyl-(1 --> 6)-beta-D-glucopyranoside and 3-O-beta-D-glucuronopyranosyl-24-hydroxy-olean-12-en-28-oic acid 28-O-beta-D-glucopyranoside, for rivalosides C-E, respectively. The taxonomic significance of the rivalosides in G. rivale was discussed.

Comparison of vector and conventional bioelectrical impedance analysis in the optimal dry weight prescription in hemodialysis

BACKGROUND

Dry weight prescription is commonly based on symptoms induced by inappropriate fluid removal by hemodialysis (HD). Aim of this study was to compare the assessment of volume status by conventional bioelectrical impedance analysis (BIA) and the resistance-reactance (RXc) graph method in HD patients achieving their target dry weight determined on clinical criteria.

METHODS

We studied 39 HD patients (23 males and 16 females, mean age 52 +/- 17 years, dialytic age 41.2 +/- 37 months). Dry weight, prescribed according to the standard clinical criteria, was constantly achieved in the last 3 months. Patients symptom-free over the last 3 months were defined as asymptomatic. Patients with either muscular cramps or hypotensive episodes were defined as symptomatic. Thirty-three healthy volunteers (11 males, 22 females, mean age 50 +/- 11 years) constituted the control group. Standard, single frequency (50 kHz), tetrapolar, BIA measurements were obtained in controls, and in patients before, every 60 min, and 30 min after one HD session. Total body water (TBW), and extracellular water (ECW) were calculated using conventional BIA regression equations. In both groups, tissue hydration was also assessed by the RXc graph method.

RESULTS

On the basis of 95% tolerance interval (mean +/- 2 SD) for the ECW (%) calculated in healthy subjects (ECW = 35-44%), HD patients were divided into 3 groups according to their post-HD ECW: 72% normohydrated with ECW 35-44%, 10% overhydrated with ECW >44%, and 18% underhydrated with ECW <35%. Patients were also classified into 3 categories according to the RXc graph method: 38% normohydrated with vectors within the reference 75% tolerance ellipse, 0% overhydrated with short vectors below the lower pole of the 75% tolerance ellipse, and 62% underhydrated with long vectors above the upper pole of the 75% tolerance ellipse. The progressive removal of body fluid during HD treatment was associated with a progressive increase in both impedance vector components, R and Xc. Eleven of thirty-nine patients (28%) were symptomatic during HD treatment in the last 3 months. The majority of these (73%) were classified as normohydrated according to ECW estimates, while 9 and 18% were classified as over- and underhydrated, respectively. This frequency distribution was significantly different from that obtained with the RXc graph method (chi(2) = 6.9, p = 0.03) where the majority (73%) were classified as underhydrated, while 0 and 27% were classified as over- and normohydrated, respectively. The frequency distribution of the 28 asymptomatic patients also significantly differed between conventional BIA and RXc graph hydration categories (chi(2) = 10.8, p = 0.005), since 11, 71 and 18% vs. 0, 43 and 57% of patients were classified as over-, normo-, and underhydrated, respectively.

CONCLUSIONS

The classification of volume status based on conventional BIA was insensitive to either clinical situation (presence or absence of symptoms). In contrast, the classification based on the RXc graph was consistent with the clinical course in symptomatic patients (73% dehydrated, and 27% normohydrated), while it did not reflect the clinical course in asymptomatic patients, 57% of whom were classified as (already) underhydrated. A longitudinal study will establish the clinical usefulness of RXc graph indications in asymptomatic patients.

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.

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.

A new cacospongionolide derivative from the sponge Fasciospongia cavernosa

Cacospongionolide F (4a), a new bioactive cacospongionolide-related sesterterpene, has been isolated from the Northern Adriatic sponge Fasciospongia cavernosa. The structure was proposed on the basis of spectroscopic data and chemical transformations. The absolute configuration was established using the modified Mosher's method. A molecular mechanics study of the dehydrodecalin ring explained the observed differences in dynamic behavior between cacospongionolide F and mamanuthaquinone, a related compound. Antimicrobial activity, brine shrimp and fish lethalities of this new compound are reported.

How the ovarian follicle of Podarcis sicula recycles the DNA of its nurse, regressing follicle cells

In Podarcis sicula specialized follicle cells send reserve materials to the previtellogenic oocyte via intercellular bridges. Immediately before the onset of vitellogenesis this transferring becomes particularly massive so that the cell volume significantly reduces, meanwhile in the nucleus the morphological alterations typical of apoptosis appear. To clarify why these follicle cells are not simply fully resorbed by the oocyte and to determine whether their DNA is discarded or recycled, we carried out a series of morphological and biochemical investigations. The finding that large macromolecular scaffolds are formed and that these are able to retain the DNA until it is extensively cut by two different endonucleases suggests that regression of the follicle cells is programmed and that the fate of their DNA is strictly controlled. Following its genetical neutralization via fragmentation, the DNA is apparently recycled by being transferred into the oocyte via the intercellular bridges, that, in fact, remain open until the very late stages of cell regression. The small DNA fragments reaching the oocyte cytoplasm would not interfere with meiosis completion but could significantly contribute to the stock of reserve materials to the advantage of the growing oocyte and/or developing embryo.

A new cacospongionolide inhibitor of human secretory phospholipase A2 from the Tyrrhenian sponge Fasciospongia cavernosa and absolute configuration of cacospongionolides

A new inhibitor of human secretory phospholipase A2 (PLA2), cacospongionolide E (4a), has been isolated from the Tyrrhenian sponge Fasciospongia cavernosa. The structure was proposed on the basis of spectroscopic data and by chemical transformations. The absolute configuration of cacospongionolides 2a-4a was established using the modified Mosher's method. Cacospongionolide E was the most potent inhibitor toward human synovial PLA2, showing higher potency than the reference compound manoalide and exerting no signs of toxicity on human neutrophils. It showed high activity in the Artemia salina bioassay and moderate toxicity in the fish (Gambusia affinis) lethality assay.

Cacospongionolide B, a new sesterterpene from the sponge Fasciospongia cavernosa

Cacospongionolide B [2a], a new cacospongionolide-related sesterterpene, has been isolated from the Adriatic sponge Fasciospongia cavernosa. The structure was elucidated by spectral and chemical means. The antimicrobial activity and brine shrimp and fish lethalities of 2a are reported.

Biological effects of prenylated hydroquinones: structure-activity relationship studies in antimicrobial, brine shrimp, and fish lethality assays

Twenty-three hydroquinone and quinone derivatives were assayed for antimicrobial effects and brine shrimp and fish lethalities, to establish relevant structure-activity relationships (SAR). Linear 2-prenyl-1,4-hydroquinones used for bioassay were obtained either by isolation from the sponge Ircinia spinosula or by synthesis. Corresponding quinones, as well as hydroquinones possessing saturated side-chains composed of one to eight isopentane units, were also synthesized and biologically evaluated. Terpenoid 1,4-benzoquinones displayed moderate antimicrobial activity against three microorganisms, SAR studies indicate the optimum length of the side-chain is in the range of five to fifteen carbon atoms.

Spinocerebellar ataxia (SCA1) in two large Italian kindreds: evidence in favour of a locus position distal to GLO1 and the HLA cluster

Two large Italian pedigrees with HLA-linked spinocerebellar ataxia (SCA1) were typed for HLA-A, -B and -DR as well as for markers either distal (F13A, D6S8) or proximal (D6S29, GLO1) to HLA. Pairwise linkage analyses of SCA1 vs. HLA-A, -B, and -DR showed peak lodscores of 5.3, 5.6 and 3.3 respectively at 7% recombination. Negative lodscores significantly excluded linkage with F13A at less than 5% and with GLO1 at less than 10%. The lodscores with D6S8 and D6S29 had only low peaks. Recombination events in the two pedigrees and the estimated genetic distances of SCA1 from GLO1 and HLA favour the hypothesis of a SCA1 location distal to both of them. An order cen-GLO1-HLA-SCA1-tel appears therefore most likely with present data. These results are discussed in relation to previous reports placing SCA1 distal to HLA in two families and

The human Y chromosome shows a low level of DNA polymorphism

Six new Y-specific probes have been isolated and are reported. Along with another six already described they have been used in a systemic search for male specific RFLPs. An overall number of 46515 nucleotides have been screened with 12 enzymes and no polymorphic pattern observed. Our data reveal a greatly reduced level of polymorphism compared with other chromosomes.

Mitochondrial DNA polymorphisms in Italy. I. Population data from Sardinia and Rome

The polymorphisms of human mitochondrial DNA were studied in about 150 Sardinians from Cagliari and 100 other Italians living in Rome, using total blood cell DNA and the following restriction enzymes: HpaI, BamHI, HaeII, MspI, AvaII and HincII. 1. Seven different new morphs have been identified, one for HaeII, four for AvaII and two for HincII. 2. 16 and 17 mtDNA types were observed in the Sardinian and Roman samples, respectively. Of these only seven were shared by both groups. The morphs BamHI-3, MspI-4 and AvaII-9 were found associated at a frequency (10.0%) much higher than expected (0.17%). 3. Sardinians can be differentiated from the other Italians for a higher frequency of both morph AvaII-1 (P less than 0.05) and type 1 (2-1-1-1-1) (P approximately less than 0.03), and for a lower intragroup heterogeneity (0.52 v. 0.61). 4. The Italian sample on the whole can also be differentiated from the Caucasian group previously examined for a lower frequency of BamHI morph 2 (P Yates less than 0.01), a higher frequency of HaeII morph 1 (P Yates less than 0.02) and for the presence at a non-negligible incidence (5 individuals out of 229) of the new type 57-2 (2-3-1-4-13-2). The data indicate that mtDNA polymorphisms have not only proved to be a useful tool in detecting differences among major human groups but they can also differentiate populations within the same major ethnic division.

Population studies on human phosphoglucomutase-1 thermostability polymorphism

The electrophoretic and thermostability polymorphisms of the PGM1 locus were examined in about 700 Czechoslovakians (Prague) and 3000 Italians. The Italian sample consisted of individuals from Pavia (Northern Italy), Viareggio and Rome (Central Italy) and Naples (Southern Italy). The eight PGM1 alleles, PGM1Str1, PGM1Sts1, PGM1Ftr1, PGM1Fts1, PGM2Str1, PGM2Sts1, PGM2Ftr1, PGM2Fts1, have been considered as combinations of mutations at three different sites, 1/2, S/F and tr/ts, within the PGM1 gene and their frequencies discussed in terms of linkage disequilibrium between these sites. All pairwise differences between the samples were significant except for Pavia-Viareggio and Viareggio-Rome. The frequencies of the PGMts1 alleles have been found to range from 0.0981 (Prague) to 0.0546 (Naples) and can be ordered according to a North-South cline.

Further genetic heterogeneity of human red cell phosphoglucomutase-1: a mon-electrophoretic polymorphism

The electrophoretic patterns of human red cell phosphoglucomutase (PGM) were determined by standard starch-gel electrophoresis on two aliquots of haemolysate, one of which was previously heat-treated. Samples from 67 families and 417 unrelated healthy subjects were examined. Heat denaturation studies combined with electrophoresis showed a greater heterogeneity of phosphoglucomutase-1 (PGM1) isozymes than that revealed by electrophoresis alone. Both PGM11 and the PGM21 isozymes turned out to be either heat-resistant (tr) or heat-sensitive (ts) and this new phenotypic property segregated along with the electrophoretic allele with which it was originally associated. Comparison of red cell PGM1 patterns of 217 PGM21-1 heterozygous individuals, analysed both as described in this paper and by acid starch-gel electrophoresis, which also distinguishes two common PGM11 (PGM1S1 and PGM1f1) and two common PGM12 (PGM2S1 and PGM2F1) allelic products, has shown that the two sets of four alleles do not coincide. Thus eight different PGM1 alleles were identified. The PGM1Str1, PGM1Sts1, PGM1Ftr1, PGM1FTSts1, PGM2Str1, PGM2Sts1, PGM2Ftr1 and PGM2Fts1 gene frequencies were estimated as 0 . 523, 0 . 066, 0 . 099, 0 . 029, 0 . 224, 0 . 012, 0 . 043, 0 . 004, respectively. Three polymorphic sites are hypothesized within the PGM1 structural gene and the observed frequencies of the eight alleles discussed in terms of 'disequilibrium' among these sites. This is the second example of a human enzyme isoelectrophoretic polymorphism revealed by research specifically aimed at detecting electrophoretically cryptic genetic variations. The technique used in this study appears to offer a reliable means of detecting isoelectrophoretic variants for proteins already known to be electrophoretically polymorphic.