Aging and time-based prospective memory in the laboratory: a meta-analysis on age-related differences and possible explanatory factors.

In older adults' everyday life, time-based prospective memory (TBPM) is relevant as health-related intentions are often part of daily activities. Nonetheless, it is still unclear which task-related factors can potentially moderate the magnitude of age-related differences, such as duration of the PM target time (the time-window within which an individual must complete a given TBPM task), the frequency of the TBPM tasks, and the criterion chosen to compute PM accuracy. The present meta-analysis aimed to quantify age-related differences in laboratory TBPM tasks, and to investigate how specific task-related factors potentially moderate the magnitude of age effects. The results showed that age effects consistently emerged among the studies, with older adults showing lower TBPM performance and checking the clock less often than younger adults, especially for shorter intervals (e.g., ≤ 4 min). Furthermore, the results indicated that the duration of the PM target time interacted with the frequency of the PM task, suggesting that learning effects may attenuate the magnitude of age differences in TBPM performance. The results are discussed in terms of potential implications about the possible cognitive processes involved in TBPM and aging, as well as in terms of robustness of the TBPM laboratory paradigm in aging research.

Do the young and the old perceive emotional intervals differently when shown on a younger or older face?

Many authors have analysed the effects of emotion recognition on time perception, showing that the more arousing the stimuli are the greater is the effect on duration perception. Visual stimuli, in particular faces, are the most recurrent stimuli employed in the literature. However, pictures in which emotional faces of older individuals have rarely been used, and when used, only young participants were tested. Hence, the present study is designed not only to analyse differences as regards duration perception in younger and older participants, but also to investigate the effects of neutral, happy, and angry facial expressions on younger and older participants when younger or older faces express those emotions. Results showed overestimation when emotional stimuli were presented. Interestingly, we observed temporal underestimation when the temporal intervals were marked by the image of younger participants and this was true in particular for older adults participants. Results are discussed in accordance with the internal clock model and in accordance with an inferential/reconstructive process occurring in memory and acting on temporal judgments.

Jumping to Conclusions bias, BADE and Feedback Sensitivity in schizophrenia and schizotypy.

Several studies about schizophrenia have shown a cognitive bias named "Jumping to Conclusions" (JTC), defined as a decision made quickly on the basis of little evidence that occurs in these patients when performing probabilistic reasoning paradigms. The main objective of this study is to compare JTC bias and BADE (Bias Against Disconfirmatory Evidence) in patients with schizophrenia vs. participants with high/low schizotypy to understand the underlying mechanism of these cognitive biases. Probabilistic reasoning was assessed using a modified version of Drawing to Decision task. In addition to the traditional parameters of this task (Plausibility Rating (PR), Draws to Decision (DTD), BADE) we also calculated new parameters, overall accuracy and one named Feedback Sensitivity (FS) which lower scores shows greater use of feedback. The results of the study suggest a context effect: in the cued condition, there were not main differences between groups. In the uncued condition, we found higher JTC bias at stage 1 for patients. At the same time, PR at first stages related positively with Feedback Sensitivity and negatively with accuracy for patients and high schizotypy participants (high confidence is associated with worse performance and lower feedback use). BADE seems unrelated to JTC bias and FS. The results are discussed in terms of JTC like as a clinical bias and whether patients with schizophrenia are less able to use feedback.

Duration, numerosity and length processing in healthy ageing and Parkinson's disease.

People constantly process temporal, numerical, and length information in everyday activities and interactions with the environment. However, it is unclear whether quantity perception changes during ageing. Previous studies have provided heterogeneous results, sometimes showing an age-related effect on a particular quantity, and other times reporting no differences between young and elderly samples. However, three dimensions were never compared within the same study. Here, we conducted two experiments with the aim of investigating the processing of duration, numerosity and length in both healthy and pathological ageing. The experimental paradigm consisted of three bisection tasks in which participants were asked to judge whether the presented stimulus (i.e. a time interval, a group of dots, or a line) was more similar to the short/few or long/many standards. The first study recruited healthy young and elderly participants, while the second recruited healthy elderly participants and patients with Parkinson's disease, a clinical condition commonly associated with temporal impairments. The results of both experiments showed that discrimination precision differed between domains in all groups, with higher precision in the numerosity task and lower sensitivity in judging duration. Furthermore, while discrimination abilities were affected in healthy elderly and, even more so, in Parkinson's disease group, no domain-specific impairments emerged. According to our research, reduced discrimination precision might be explained by an alteration of a single system for all quantities or by an age-related general cognitive decline.

Time perception in severe traumatic brain injury patients: a study comparing different methodologies.

In this study, we investigated time perception in patients with traumatic brain injury (TBI). Fifteen TBI patients and 15 matched healthy controls participated in the study. Participants were tested with durations above and below 1s on three different temporal tasks that involved time reproduction, production, and discrimination tasks. Data variables analyzed included amount of errors, relative errors, and coefficient of variation. Both groups completed a neuropsychological battery that included measures of attention, working memory, and executive functions. Results revealed significant differences between groups on the time reproduction and discrimination tasks, whereas groups showed similar performance on the time production task. Correlation analyses showed involvement of attention, working memory and executive functions on the time reproduction and time discrimination tasks, but there was no involvement on the time production task. These findings suggest that TBI does not impact specific temporal function. Rather, impairments in attention, working memory and executive function abilities may explain lower temporal performance in people with TBI.

The contribution of the supplementary motor area to explicit and implicit timing: A high-definition transcranial Random Noise Stimulation (HD-tRNS) study.

It is becoming increasingly accepted that timing tasks, and underlying temporal processes, can be partitioned on the basis of whether they require an explicit or implicit temporal judgement. Most neuroimaging studies of timing associated explicit timing tasks with activation of the supplementary motor area (SMA). However, transcranial magnetic stimulation (TMS) studies perturbing SMA functioning across explicit timing tasks have generally reported null effects, thus failing to causally link SMA to explicit timing. The present study probed the involvement of SMA in both explicit and implicit timing tasks within a single experiment and using High-Definition transcranial Random Noise Stimulation (HD-tRNS), a previously less used technique in studies of the SMA. Participants performed two tasks that comprised the same stimulus presentation but differed in the received task instructions, which might or might not require explicit temporal judgments. Results showed a significant HD-tRNS-induced shift of perceived durations (i.e., overestimation) in the explicit timing task, whereas there was no modulation of implicit timing by HD-tRNS. Overall, these results provide initial non-invasive brain stimulation evidence on the contribution of the SMA to explicit and implicit timing tasks.

Understanding time perception through non-invasive brain stimulation techniques: A review of studies.

The present review includes transcranial magnetic and transcranial electric stimulation studies on time perception and shows that the neural processing of time requires the activity of wide range-distributed brain networks. Moreover, a critical discussion regarding non-invasive brain stimulation in the study of time processing is included to give the reader insights into the study of temporal processing in neuroscience. The cerebellum and auditory cortex seem most crucial when participants are required to estimate the passage of sub-seconds intervals and this conclusion holds independently of the modality used to mark the temporal intervals. Conversely, the primary visual area and MT/V5 seem to process primarily visual stimuli. The areas included in the prefrontal cortex are mostly implicated in the processing of supra-second time intervals and when time is processed in conjunction with other cognitive functions. Although previous fMRI studies showed activation in the supplementary motor area during sub-second timing tasks, TMS studies failed to confirm these observations. We conclude that the contribution of these strongly interconnected structures in the processing of temporal information is not fixed; their contribution depends not only on the duration of the time interval to be assessed by the brain but also on the cognitive set involved in the chosen task and on the stimulus modality used for marking time. Critical observations regarding the specificity of each method of stimulation as well as limitations and criticisms of the studies that used brain stimulation techniques will be also discussed.

[Nutrition, acid-base metabolism, cation-anion difference and total base balance in humans]. / Nutrizione ed equilibrio Acido-Base, differenza Cationi-Anioni e bilancio di basi nell'uomo.

The relationship between dietary intake and acid-base metabolism has been investigated in the past by means of the inorganic cation-anion difference (C(+)(nm)-A(-)(nm)) method based on dietary ash-acidity titration after the oxidative combustion of food samples. Besides the inorganic components of TA (A(-)(nm)-C(+)(nm)), which are under renal control, there are also metabolizable components (A(-)(nm)-C(+)(nm)) of TA, which are under the control of the intermediate metabolism. The whole body base balance, NBb(W), is obtained only by the application of C(+)(nm)-A(-)(nm) to food, feces and urine, while the metabolizable component (A(-)(nm)-C(+)(nm)) is disregarded. A novel method has been subsequently suggested to calculate the net balance of fixed acid, made up by the difference between the input of net endogenous acid production: NEAP = SO(4)(2-)+A(-)(m)-(C(+)(nm)-A(-)(nm)), and the output of net acid excretion: NAE = TA + NH(4)(+) - HCO(3)(-). This approach has been criticized because 1) it includes metabolizable acids, whose production cannot be measured independently; 2) the specific control of metabolizable acid and base has been incorrectly attributed to the kidney; 3) the inclusion of A-m in the balance input generates an acid overload; 4) the object of measurement in making up a balance has to be the same, a condition not fulfilled as NEAP is different from NAE. Lastly, by rearranging the net balance of the acid equation, the balance of nonmetabolizable acid equation is obtained. Therefore, any discrepancy between these two equations is due to the inaccuracy in the urine measurement of metabolizable cations and/or anions.

A tRNS investigation of the sensory representation of time.

The understanding of the mechanisms underlying the representation of temporal intervals in the range of milliseconds/seconds remains a complex issue. Different brain areas have been identified as critical in temporal processing. The activation of specific areas is depending on temporal range involved in the tasks and on the modalities used for marking time. Here, for the first time, transcranial random noise stimulation (tRNS) was applied over the right posterior parietal (P4) and right frontal (F4) cortex to investigate their role in intra- and intermodal temporal processing involving brief temporal intervals (<1 sec). Eighty University students performed a time bisection task involving standard durations lasting 300 ms (short) and 900 ms (long). Each empty interval to be judged was marked by two successive brief visual (V) or auditory (A) signals defining four conditions: VV, VA, AV or AA. Participants were assigned to one of these four conditions. Half of the participants received tRNS over P4 and half over F4. No effect of stimulation was observed on temporal variability (Weber ratio). However, participants that were stimulated over P4 overestimated temporal intervals in the random condition compared to the sham condition. In addition to showing an effect of tRNS on perceived duration rather than on temporal variability, the results of the present study confirm that the right posterior parietal cortex is involved in the processing of time intervals and extend this finding to several sensory modality conditions.

The role of primary auditory and visual cortices in temporal processing: A tDCS approach.

AIM: Many studies showed that visual stimuli are frequently experienced as shorter than equivalent auditory stimuli. These findings suggest that timing is distributed across many brain areas and that "different clocks" might be involved in temporal processing. The aim of this study is to investigate, with the application of tDCS over V1 and A1, the specific role of primary sensory cortices (either visual or auditory) in temporal processing. METHOD: Forty-eight University students were included in the study. Twenty-four participants were stimulated over A1 and 24 participants were stimulated over V1. Participants performed time bisection tasks, in the visual and the auditory modalities, involving standard durations lasting 300ms (short) and 900ms (long). RESULTS: When tDCS was delivered over A1, no effect of stimulation was observed on perceived duration but we observed higher temporal variability under anodic stimulation compared to sham and higher variability in the visual compared to the auditory modality. When tDCS was delivered over V1, an under-estimation of perceived duration and higher variability was observed in the visual compared to the auditory modality. CONCLUSION: Our results showed more variability of visual temporal processing under tDCS stimulation. These results suggest a modality independent role of A1 in temporal processing and a modality specific role of V1 in the processing of temporal intervals in the visual modality.

Renoprotective effect of early inhibition of the renin-angiotensin system in renal transplant recipients.

The aim of this work was to study the effect of early administration of angiotensin-converting enzyme inhibitors (ACEI) and angiotensin II type-I receptors blockers (ARB) on renal function and proteinuria in renal transplant recipients with good, stable renal function and mild proteinuria. Twenty four patients started ACEI/ARB therapy within 14 months after surgery (RAS-). Before (T0) and every month for 2 years after the initiation of ACEI/ARB we evaluated creatinine clearance (CrCl), proteinuria/day (UP), UP/CrCl (FUP), arterial blood pressure, and serum lipid levels. Twenty-eight patients who never received ACEI/ARB (RAS+) were studied in the same fashion. In the RAS+ CrCl was reduced after 2 years compared with T0 (64.5 +/- 2.6 vs 75.0 +/- 3.2 mL/min, P < .003); UP and FUP were both significantly increased (666 +/- 65 vs 132 +/- 20 mg/day 8.8 +/- 1.2 vs 2.6 +/- 0.6 mg/mL x 10(3); P < .001 and .002) compared with T0. Moreover, UP (P < .04), FUP (P < .03), and the percentage reduction of CrCl (11.4% +/- 5% vs 4.6% +/- 1.8%; P < .05) were greater in RAS+ than RAS- subjects at 2 years of the study. The values of other parameters did not show significant differences between the two groups. In conclusion, this study suggested that ACEI/ARB have renoprotective effects, when used in patients with good stable renal function and mild proteinuria. These drugs may play a role to prevent chronic allograft nephropathy.

Effects of successful renal transplantation on left ventricular mass.

Left ventricular hypertrophy is an independent cardiovascular risk factor in the general population and in patients with chronic renal failure. Relatively little is known about the effects of renal transplantation on left ventricular hypertrophy. The aim of this study was to determine the changes in left ventricular mass after successful renal transplantation and to evaluate the importance of some clinical, laboratory, and echocardiographic variables on the trend to left ventricular hypertrophy. Twenty-three patients with end-stage renal disease were studied by ambulatory blood pressure monitoring and echocardiography before and 2 years following renal transplantation. After 24 months of follow-up, all transplant recipients had adequate renal function (serum creatinine <2 mg/dL). At the end of the study, we observed a significant decrease in left ventricular mass and left ventricular mass index compared to the pretransplantation period. In renal transplant recipients, the prevalence of left ventricular hypertrophy significantly decreased (78% versus 44%, P < .03) after 2 years of follow-up. Systolic 24-hour blood pressure was the only predictor of left ventricular mass and of left ventricular mass index at 2 years after transplantation. In conclusion, successful renal transplantation produces a regression of left ventricular hypertrophy. This beneficial effect depends on a decrease in systolic pressure levels.

Event-based prospective memory in patients with Parkinson's disease: the effect of emotional valence.

The present study investigated the effect of Parkinson's disease (PD) on prospective memory (PM) tasks by varying the emotional content of the PM actions. Twenty-one older adults with PD and 25 healthy older adults took part in the present study. Participants performed three virtual days in the Virtual Week task. On each virtual day, participants performed actions with positive, negative or neutral content. Immediately following each virtual day, participants completed a recognition task to assess their retrospective memory for the various PM tasks. PD patients were less accurate than the control group at both PM accuracy and recognition task accuracy. The effect of emotional valence was also evident, indicating that all participants were more accurate on positive PM tasks than both negative and neutral. This study confirmed PM impairment in PD patients and extended previous research showing how positive emotional stimuli can influence PM performance.

Derangement of acid-base balance in uremia and under hemodialysis.

Uremic acidosis is due to impaired excretion of ammonium ions in the presence of unchanged acid production. However, the degree of acidosis is quite variable among uremic patients and pre-dialytic bicarbonate levels are mainly independent of dialytic base supply. These observations strengthen the suggestion that extra-renal mechanisms may play a significant role in controlling acid-base balance in uremic patients. The possible effects of diet, intestine, bone, intermediate metabolism, and the global acid-base balance are discussed. The metabolic and clinical effects of mild uremic acidosis are not well defined. In fact, no long-term clinical study have produced clear evidence for increased protein catabolism in humans. Some data provide evidence for reduced bone mineral content and osteomalacic lesions in uremic patients with severe acidosis. Overall, the impact of the present dialytic techniques on acid-base control is quite small, since no major difference is observed in uremic patients treated with different dialytic schedules. Furthermore, the base supply by dialysis does not seem to represent the main mechanism for acid-base correction by dialysis. In conclusion, at present time, metabolic acidosis of uremic patients is often mild and not accompanied by major symptoms. Probably, more attention needs to be paid to the possible noxious effect of over-correction of acidosis.

Alterations in renal tubular sodium and water transport in polycystic kidney disease.

Thirty patients with chronic renal diease -10 with polycystic kidney disease (PKD) and normal GFR; 10 with PKD and GFR is less than 30 ml+min; 10 with chronic glomerulonephritis (CGN) and GFR is less than 30 ml+min -and 10 normal subjects were investigated. The ability to concentrate urine maximally (T-CH2O) after water deprivation and the renal handling of water and electrolytes following hypertonic volume expansion were studied. A defect in T-CH2O was common in PKD patients even with normal GFR. In PKD patients with normal GFR, volume expansion was not followed by a natriuretic effect of the same magnitude as in controls. This ""inadequate natriuresis after volume expansion"" may be explained partly by chronic hyponatremia and partly by a functional defect, i.e. the incomplete arterial vasodilation in the kidney. At comparable degrees of renal insufficiency, T-CH2O was lower in PKD than in CGN patients. It seems likely that in PKD patients the increased endogenous osmotic load has exaggerated the tubular defect in urine concentration already present at normal GFR. Furthermore, volume expansion was followed by a significant increase in fractional sodium excretion only in PKD patients with renal insufficiency.

Long-term therapy for postrenal transplant erythrocytosis with ACE inhibitors: efficacy, safety and action mechanisms.

SUBJECTS AND METHODS: Eleven patients with postrenal transplant erythrocytosis were treated with angiotensin-converting enzyme inhibitors for 18 months. RESULTS: Indices of red blood cell production and destruction, renal function and kalemia were followed-up during the treatment. Angiotensin-converting enzyme inhibitors (ACEi) led to a progressive and significant fall in hemoglobin and hematocrit compared to the basal values at every time interval considered with a maximum reduction at 12th month for hemoglobin ( 17.04 +/- 0.21 vs. 15.10 +/- 0.42 g/dl, p < 0.0001) and at the 6th month for hematocrit (53.74 +/- 0.56 vs. 45.7 +/- 1.19 %, p < 0.0001). Serum erythropoietin levels were reduced significantly after the first month of therapy (13.56 +/- 2.7 vs. 7.48 +/- 1.6 mUI/dl, p < 0.05) after which no further variations were recorded. In the course of ACEi therapy, there was an inverse correlation between percentage reduction in erythropoietin values and those of hemoglobin emerged (r = 0.24, p < 0.05) and hematocrit (r = 0.39, p < 0.01). Indices of red blood destruction including haptoglobin, bilirubin and lactic dehydrogenase, were unaffected by ACE inhibitors treatment, as was creatininemia and kalemia. Treatment was well tolerated by all patients who completed the study without major adverse side-effects. No patient required phlebotomy and no thromboembolic event occurred during angiotensin-converting enzyme therapy. CONCLUSIONS: Our results suggest that angiotensin-converting enzyme inhibitors are a safe and effective long-term therapy of postrenal transplant erythrocytosis. These agents decrease the erythropoietin synthesis but this effect is not the sole mechanism by which angiotensin-converting enzyme inhibitors act in postrenal renal transplant erythrocytosis.

Insertion of a straight peritoneal catheter in an arcuate subcutaneous tunnel by a tunneler: long-term experience.

OBJECTIVE: This study describes the results of the insertion of a straight Tenckhoff peritoneal catheter (PC) in an arcuate, caudally concave tunnel using a tunneler designed by the authors. It has a semicircular shape and a bending radius of 4.5 cm. SETTING: A hospital renal unit. PATIENTS: From June 1988 to February 1994, 112 straight Tenckhoff PCs, 62 with one deep cuff (single-cuff PC) and 50 with two cuffs (double-cuff PC), were inserted as first catheters in 112 patients (mean age 62 +/- 13 years), who underwent continuous ambulatory peritoneal dialysis (CAPD). The follow-up was 1099 months (mean 18 +/- 13 months) for single-cuff PCs and 1264 months (mean 25 +/- 15 months) for double-cuff PCs, respectively. INTERVENTIONS: After intraperitoneal placement of the PCs by median laparotomy, a 180 degrees arc bend tunnel, with both external and peritoneal exits directed downwards, was created by means of the tunneler. RESULTS: The rate of exit-site infection (ESI) was 0.27 episodes/year (epis/year). The probability of remaining ESI-free was 76%, 60%, and 55% at 1, 2, and 3 years. The rate of tunnel infection (TI) was 0.046 epis/year. The incidence of the double-cuff PC-related ESI and TI tended to be lower than the incidence observed with the single-cuff PC. Episodes of peritonitis were 60 (0.30 epis/year), where 6 were subsequent to ESI and/or TI. Two PCs were lost due to ESI, 3 due to TI, and 11 due to peritonitis. Drainage failure, due to displacement of the PC caused by straightening, involved 3 PCs; 2 were lost. PC survival was 92%, 82%, and 74% at 1, 2 and 3 years, respectively. CONCLUSIONS: By an easily used semicircular tunneler, the standard straight Tenckhoff PC can be stably positioned in an arcuate tunnel with both inner and outer exits directed downwards. This tunnel shape, as already suggested by some authors, appears to be an effective technical solution to reducing the PC-related complication rates.

Peritoneal clearances in hypertensive CAPD patients after oral administration of clonidine, enalapril, and nifedipine.

The authors investigated whether the reduction of arterial pressure, induced by the oral administration of clonidine (CLO), enalapril (EN), and nifedipine (NIF), has any effect on peritoneal transport rates. The study was performed in nine hypertensive patients undergoing continuous ambulatory peritoneal dialysis (CAPD). The patients were submitted to administration of CLO, EN, and NIF, each in randomized succession for two weeks, after withdrawal of any hypotensive therapy for eight days (washout period). The nine patients underwent a four-hour dwell exchange using a 2.27 g/dL glucose two-liter bag after washout and after each hypotensive period. The following parameters were analyzed: mean arterial pressure (MAP), performed in the sitting position; net ultrafiltration; effluent/initial dialysate glucose ratio (GL D/Do); peritoneal clearance of K, BUN, creatinine (Cr), phosphate, beta-2 microglobulin (beta 2), total proteins, and the ratio between beta 2 and Cr clearance. Moreover, residual renal Cr and beta 2 clearances were analyzed. The three drugs significantly reduced MAP at a similar rate. The peritoneal transport parameters after CLO were similar to the results in the washout period. On the contrary, after EN and NIF therapy, Cr and beta 2 clearances were significantly increased, and GL D/Do decreased in comparison to the washout period. The other peritoneal transport parameters after EN and NIF were similar to the washout period. Residual renal Cr and beta 2 clearances after the three drugs were similar to those in the washout. these data suggest that after two weeks of therapy with EN and NIF, glucose, Cr, and beta 2 peritoneal transports are influenced by these hypotensive drugs irrespective of the effect on the arterial pressure.(ABSTRACT TRUNCATED AT 250 WORDS)

Renal allograft protection with early angiotensin-converting enzyme inhibitors administration.

Twenty renal transplant recipients (RTx) with a normal ultrasound pattern of renal artery who began angiotensin-converting enzyme inhibitor (ACEI) therapy within 14 months after surgery (ACEI(+)) were studied retrospectively to evaluate endogenous creatinine clearance/1.73 m(2) body surface area (CrCl), proteinuria (UP), UP/CrCl (FUP), mean arterial pressure (MBP), total cholesterol, LDL, HDL, and triglycerides. Before (T(0)) and every month for 2 years after initiation of ACEI. Twenty-four RTx who never received ACEI (ACEI(-)) were studied in the same fashion. No differences in the parameters were noted at T(0); all RTx had CrCl >60 mL/min, Up less than 0.5 g/d, and stable renal function for 3 months before the study. In the ACEI cohort CrCl was reduced after 2 years compared with T(0) (65.6 +/- 2.8 vs 76 +/- 3.2 mL/min, P <.004), UP and FUP were both increased (660 +/- 60 vs 130 +/- 20 mg/d, 8.9 +/- 1.3 vs 2.8 +/- 0.6 mg/mL x 10(3); P <.001 and.002, respectively). UP >0.5 g/d was present in three cases. After 2 years the ACEI(+) group showed a decrease in CrCl (68.2 +/- 3.1 vs 73 +/- 2.2 mL/min) and the increase in UP (181 +/- 21 vs 139 +/- 18 mg/d) and in FUP (3.1 +/- 0.7 vs 2.6 +/- 0.9 mg/mL x 10(3)), which were not significantly different from the values at T(0). No cases showed UP >0.5 g/d. Moreover UP (P <.04), FUP (P <.03) and the percent reduction of CrCl (11.2 +/- 2.5% vs 4.6 +/- 1.8%, P <.05) were greater among ACEI(-) than ACEI(+) patients at 2 years. ACEI(-) patients showed correlation between the percent reduction of CrCl and UP (r =.51, P <.04). The values of MBP and lipids did not reveal any significant difference between the two groups. In conclusion, this study suggests that ACEI have a renoprotective effect, when used early, and may also prevent chronic allograft nephropathy.

[Surgical complications after kidney transplantation]. / Le complicanze chirurgiche ed urologiche del trapianto di rene.

Chronic renal failure needs substitutive treatment such as haemodialysis and peritoneal dialysis for the patient to survive. Kidney transplantation (KTx) improves survival of the patient with chronic renal failure. Since the first KTx, performed by Merrill in Boston in 1959, advances in medical therapy, immunosuppressive therapy and refinements in surgical technique have improved the quality of life of the transplant patient. We present a review of the incidence, diagnosis and therapy of surgical complications after KTx reported in the literature and a retrospective analysis of 297 consecutive cadaveric donor kidney transplants done in our institution from September 1993 to September 2002. Vascular complications represent 5-10% of postoperative complications. Our experience showed an incidence of 1.7% renal artery thrombosis, 1.4% renal vein thrombosis, 1.7% renal artery stenosis, 1.4% arterial rupture due to fungal arteritis, 0.7% spontaneous graft ruptures and 12% lymphoceles. Urological complications account for 10-15% of postoperative complications. In our series we found an incidence of 7.4% urinary leakage, 2.7% urinary obstruction and 3% urinary reflux. Gastrointestinal complications represent 16% of postoperative complications. Our series showed 1% pancreatitis with an overall mortality of 33% and an incidence of 1.7% intestinal perforations. Surgical complications still represent a challenge that increments morbidity and mortality among kidney transplant recipients. Data shown may offer some guidance on how to deal with early and late post-transplant surgical complications.