Can prolonged treatment improve the prognosis in adults with focal segmental glomerulosclerosis?

Eighty nephrotic adults with focal segmental glomerulosclerosis (FSGS) and plasma creatinine lower than 3 mg/dL were given corticosteroids (53 patients) or immunosuppressive agents (27 patients) for a median of 16 and 75 weeks, respectively. Forty-two patients responded with complete remission (29 patients, 36%) or partial remission (13 patients, 16%). Twenty-six patients who did not respond were treated again. Two patients obtained complete remission and 13 partial remission. The probability of remission was associated with treatment with corticosteroids (P = 0.0001; RR, 3. 93; 95% CI, 2.00 to 7.72), absence of arterial hypertension (P = 0. 0023; RR, 2.59; 95% CI, 1.41 to 4.79), and a percentage of hyaline glomeruli lower than 5% (P = 0.0152; RR, 2.04; 95% CI, 1.15 to 3.64). The probability of being alive at 110 months without doubling of plasma creatinine was 69%. The risk of renal insufficiency was correlated with mesangial proliferation (P = 0.0025; RR, 5.50; 95% CI, 1.82 to 16.60) and with interstitial fibrosis (P = 0.0231; RR, 4. 44; 95% CI, 1.23 to 16.08) at initial biopsy. Considering partial or complete remission as a time-dependent variable, only the lack of remission (P = 0.0027; RR, 7.23; 95% CI, 1.98 to 26.33) and mesangial proliferation (P = 0.0069; RR, 4.59; 95% CI, 1.52 to 13. 88) were correlated with renal failure. Major side effects were observed in 11 patients (5 infections, 1 peptic ulcer, 2 diabetes, 3 neoplasias). This study shows that 70% of nephrotic adults with FSGS may obtain complete or partial remission and maintain stable renal function for about 10 years when given a prolonged therapy with corticosteroids or immunosuppressive drugs.

Clinical and prognostic value of serial renal biopsies in lupus nephritis

Little information is available about the role of repeated renal biopsies in lupus nephritis. We analyzed retrospectively the prognostic significance of serial renal biopsies in patients with lupus nephritis. Thirty-one patients with lupus nephritis underwent two or more renal biopsies during follow-up. The indications for repeated biopsy were as follows: improvement of renal disease but persistence of nonnephrotic proteinuria (group A, 7 patients); persistent or relapsing nephrotic syndrome (group B, 12 patients); and worsening of renal function (group C, 19 patients). After a median follow-up of 10.5 years, 17 patients reached the end point (persistent doubling of plasma creatinine level). At repeated renal biopsy, there was a correlation between improved clinical and histological features for group A. In these patients, treatment was reduced or stopped successfully. Histological features remained almost unchanged in group B. All patients showed an improvement of proteinuria after reinforcement of therapy. In group C, the worsening of renal function was associated with a variable and clinically unpredictable combination of active and chronic lesions. Only the few patients with an elevated activity index and moderate chronicity index showed a favorable and persistent improvement of renal disease after reinforcement of therapy. At multivariate analysis of clinical and histological data at presentation, only male sex was predictive of an adverse outcome (P = 0.015). At repeated renal biopsy, crescents in more than 30% of glomeruli (P = 0.0009) and chronicity index of 5 or greater (P = 0.00006) were associated with the probability of reaching the end point at multivariate analysis. Repeated renal biopsy may be helpful for establishing the prognosis in patients with lupus nephritis, particularly in the presence of worsening of renal function.

Scintigraphic imaging of pituitary adenomas: an in vivo evaluation of somatostatin receptors

We have performed pituitary scintigraphy with the somatostatin (SS) analog pentetreotidean by (111In-P) in patients with GH-secreting adenoma or with "clinically non functioning" adenoma (NFA) to evaluate the presence and the functionality of SS receptors (SS-R). 111In-P pituitary accumulation was expressed as Activity Ratio (AR): the ratio between the uptake of radioactivity by the adenoma and that of the normal brain tissue. In subjects without pituitary disease, AR ranged from 1.6 to 2.2 and a value lower than 2.2 was thus arbitrarily considered as normal. In 15 out of the 17 patients with GH-secreting adenoma, an accumulation of the radioligand was shown. Median AR was 3.8 (range 1-6.9; in 14 AR were greater that 2.2) and ARs were directly correlated (r = 0.54; p < 0.05) with the suppressibility of plasma GH levels by octreotide (OC) acute administration. In two patients who repeated scintigraphy during chronic OC treatment, AR values were reduced. In all the 22 patients with NFA an accumulation of 111In-P at the pituitary level was observed and median AR was 3.0 (range 1.5-20; in 14 greater that 2.2). In vitro autoradiography of surgical specimens in 6 NFA patients revealed SS-R in 4 cases with high scintigraphic AR and negative results in two cases with low AR. Scintiscan was repeated during chronic OC treatment in 5 patients with high score: AR decreased in one patient, increased in three, and did not change in the other patient. No changes in tumor size were shown in any of these patients. A total of 8 patients (3 GH secreting and 5 NFA) had "normal" AR values.

CONCLUSIONS

In acromegaly scintigraphy with 111In-P visualizes functioning pituitary SS-R coupled to intracellular events that control hormonal hypersecretion and tumor growth. In contrast, in spite of the positivity of 111In-P imaging in most patients with NFA, their receptors might have a defect in the coupling-transduction process, as they are not inhibited by OC treatment and no tumor shrinkage is observed.

A retrospective study on the efficacy and safety of amphotericin B in a lipid emulsion for the treatment of cryptococcal meningitis in AIDS patients

To evaluate the efficacy and safety of Amphotericin B dissolved in dextrose (Amb) or in a lipid emulsion (Intralipid, Amb-IL) in AIDS patients with cryptococcal meningitis, we conducted a retrospective study in 30 AIDS patients with cryptococcal meningitis. A clinical complete resolution was obtained in 11 patients (55%) treated with Amb, and in six patients (60%) treated with Amb-IL. Intralipid did not decrease the infusion-related adverse effects, in particular nephrotoxicity and anaemia. Our results indicate that Amb-IL formulation is useful in the treatment of cryptococcal meningitis in AIDS patients, but it does not reduce the infusion-related adverse events.

Treatment of membranous lupus nephritis

In this study, we retrospectively analyzed the effects of treatment in 19 patients with membranous lupus nephritis (MLN) and nephrotic syndrome. Eight patients were treated with corticosteroids alone, and the other 11 patients received methylprednisolone and chlorambucil alternated every other month for 6 months. At presentation, sex, age, duration of renal disease before renal biopsy, plasma creatinine, and arterial hypertension were similar in the two study groups. Of the eight patients treated with corticosteroids alone, three showed complete remission and one partial remission of the nephrotic syndrome. During the follow-up (mean, 114+/-63 months), seven of these eight patients developed one or more renal flare-ups. Of the 11 patients treated with methylprednisolone and chlorambucil, seven had complete remission, and the other four had partial remission of the nephrotic syndrome. During the follow-up (mean, 83+/-59 months), only one patient had renal flare-up. At the end of the follow-up, all patients were alive, but three patients in the group treated with corticosteroids alone had developed a doubling of plasma creatinine, and another patient had persistent nephrotic syndrome. Two other patients were in complete remission, one patient was in partial remission, and the last patient had nonnephrotic proteinuria. In the group of patients treated with methylprednisolone and chlorambucil, one patient developed extracapillary glomerulonephritis and eventually entered end-stage renal failure 24 years after the clinical onset of renal disease. Seven patients were in complete remission, and three patients were in partial remission at the last follow-up visit. This retrospective study suggests that methylprednisolone and chlorambucil may induce a more stable remission of nephrotic syndrome and may better protect renal function in the long term in comparison with corticosteroids alone. However, these results must be confirmed by a prospective controlled trial.

End-inspiratory airway occlusion: a method to assess the pressure developed by inspiratory muscles in patients with acute lung injury undergoing pressure support

We evaluated the end-inspiratory occlusion maneuver as a means to estimate the inspiratory effort during pressure support ventilation (PS). In nine nonobstructed acute lung injury (ALI) patients, we applied four levels of PS (0, 5, 10, 15 cm H2O) to modify the inspiratory effort. End inspiratory occlusions (2 to 3 s) were performed at the end of each experimental period by pushing the inspiratory hold button of the ventilator (Servo 900 C; Siemens, Berlin, Germany). We took the difference between the end-inspiratory occlusion plateau pressure and the airway pressure before the occlusion (PEEP + PS) as an estimate of the inspiratory effort and called it PMI (Pmusc,index). From the esophageal pressure tracing we obtained a reference measurement of the pressure developed by the inspiratory muscles at end inspiration (Pmusc,ei) and of the pressure-time product per breath (PTP/b) and per minute (PTP/min). In each patient, PMI was correlated with Pmusc,ei (p < 0.01) and PTP/b (p < 0.01). A PMI threshold of 6 cm H2O detected PTP/min < 125 cm H2O s/min with a sensitivity of 0.89 and a specificity of 0.89. We conclude that PMI is a good estimate of the pressure developed by the inspiratory muscles in ALI patients and may be used to titrate PS level. The major advantage of PMI is that it can be obtained from the ventilator display without any additional equipment.

Automation of human sperm cell analysis by flow cytometry

Semen sample analysis is routinely performed by microscopical evaluation and manual techniques by laboratory operators; the analysis is affected by a wide imprecision related to variability among observers, influencing its clinical validity. Our aim was to automate sperm analysis with the use of flow cytometry for evaluation of cell counts and typing and with the use of a new membrane-permeant nucleic acid stain for evaluation of sperm viability. Statistical analysis of the comparison between manual and automated methods for sperm counts was performed by the Bland and Altman method; the mean difference was 0.243 x 10(6) sperms/ mL. The precision of the flow cytometric analysis was evaluated with whole sperm; the between-run CV was 7.5% and the within-run CV was 2.5%. Data observed suggest that flow cytometric sperm analysis, with high precision and accuracy and low costs, can be proposed for routine use in clinical laboratories.

Preanalytical phase in coagulation testing: state of the art in the laboratories of the Piedmont region, Italy

The control of preanalytical variables is critical, particularly for coagulation assays, since this has a direct influence on the quality of results and on their clinical reliability. The aim of the study was to evaluate the extent of information about preanalysis in the laboratories of a large region of northern Italy that perform tests of haemostasis. A questionnaire was sent concerning the number of coagulation analyses per year, the system of blood drawing, the anticoagulants and the tubes in use, the amount of blood collected, the tendency to reject unsuitable specimens, the storage temperatures, the times between collection and analysis, the conditions of tube centrifugation and identification, and the presence of staff specifically occupied in coagulation testing. Complete answers were offered by 136 laboratories (81%; 69 private and 67 public) that reported a total amount of 3,648,000 determinations per year. Statistical analysis was carried out on the findings of the investigation, in order to assess their significance and to detect possible correlations between the variables under consideration. The results show significant attention being given by laboratories to the preanalytical phase. This is also indicated by the large percentage of complete answers obtained. Some of the important positive aspects shown in the study are: (1) the preference for the closed system for blood sampling; (2) the prevalent use of primary tubes for testing; (3) a strong tendency to reject incorrect samples for analysis. On the other hand, a major problem seems to lie in the delay, particularly in some big centres, in processing of specimens, which can be critical for the correct performance of coagulation assays. The data obtained reflect with good reliability the overall situation in coagulation-testing laboratories in northern Italy.

"Nephritic flares" are predictors of bad long-term renal outcome in lupus nephritis

We retrospectively analyzed the courses of 70 patients with lupus nephritis followed for 5 to 30 years (median 127 months). Patients survival was 100% at 10 years and 86% at 20 years. The probability of not reaching the end point (persistent doubling of plasma creatinine) was 85% at 10 years and 72% at 20 years. A multivariate analysis of variables at presentation showed that male sex (P = 0.005) and hematocrit lower than 36% (P = 0.01) were associated with the end point (relative risk 7.5 and 14). We then analyzed for the role of renal flare-ups, defined either as a rapid increase in plasma creatinine or by an increase in proteinuria. Patients with renal flares of any type had more probabilities of reaching the end point than patients who never had flares (P = 0.03; relative risk 6.8). The hazard of the end point was 27 times higher in patients with flares along with rapid increased in plasma creatinine than in patients without flares or with flares with proteinuria alone (P < 0.00001). This hazard was higher when plasma creatinine did not return to the basal levels within two months after treatment (P < 0.00001).

Pepsinogens and gastrointestinal symptoms in mountain marathon runners

Although there are various descriptive reports concerning exercise-induced gastrointestinal distress, the role of gastrointestinal hormones and/or enzymes is not definitively established. In this study we investigated the behaviour of pepsinogens (PGI and PGII) after an endurance race performed at an altitude of 4,300 m by 13 well-trained marathon runners, with the aim to establish their interrelationship with gastrointestinal distress and with the modifications of gastrin and cortisol. The athletes showed a significant rise in gastrin (p < 0.01) and in cortisol (p < 0.01) and a significant decrease in PGI (p < 0.01) and PGII (p < 0.05) after the race. The PGI/PGII ratio presented small variations indicating that heavy exercise has less effects on PGs than those observed for gastrin. Gastrointestinal symptoms occurred in 6 athletes (46%) during the race and in 8 athletes (62%) after the race. No relationship was found between gastrointestinal symptoms and hormonal modifications after the race. A control group of 5 subjects was used: they (n = 5) did not show any significant modification of gastrin and PGs during the period spent at the above altitude, indicating that travel, altitude and acclimatization, food and beverages, do not influence the behaviour of these hormones. Conversely, they presented a significant decrease of cortisol (p < 0.05) linked to the circadian rhythm. The data of the present study indicate that the potential damage of gastrointestinal apparatus in mountain marathon runners is not related to the above mentioned hormones.

Extracapillary glomerulonephritis and renal amyloidosis

We report three patients with well-documented renal amyloidosis who developed rapidly progressive renal failure. Renal biopsies from all three patients showed crescentic glomerulonephritis imposed on renal amyloidosis. All patients were treated with intravenous high-dose methylprednisolone pulses combined with immunosuppressive agents and oral corticosteroids. Partial recovery of renal function was obtained in two patients. For the third patient, treatment had to be stopped after a few days because of a septic arthritis. Renal function continued to deteriorate, and the patient had to be placed on regular hemodialysis. We conclude that extracapillary glomerulonephritis may occasionally complicate a preexisting renal amyloidosis and may be reversible if recognized early and treated appropriately.

Osteocalcin production in vivo and in vitro after 1,25-dihydroxycholecalciferol stimulation comparison of different assays

The study was designed to assess the sensitivity of three commercial assays (which differ in methodology, standard and antibodies) for osteocalcin, used for detecting changes in osteocalcin secretion induced by calcitriol (1,25-dihydroxycholecalciferol) in vivo and in vitro. Osteocalcin levels were determined in serum samples of 10 osteoporotic women after short term calcitriol treatment, and in the culture medium of human osteoblast-like cells (n = 22) after 48 h calcitriol exposure. All assays displayed similar sensitivity in detecting osteocalcin production in vivo after a 1 microgram daily dose of calcitriol. A novel IRMA (CIS), claimed to detect intact osteocalcin, showed higher osteocalcin values than the other assays, and in vitro showed the best sensitivity; it provides an appropriate index of the osteocalcin synthetic activity of cultured human osteoblasts.

X-linked Alport syndrome: an SSCP-based mutation survey over all 51 exons of the COL4A5 gene

The COL4A5 gene encodes the alpha5 (type IV) collagen chain and is defective in X-linked Alport syndrome (AS). Here, we report the first systematic analysis of all 51 exons of COL4A5 gene in a series of 201 Italian AS patients. We have previously reported nine major rearrangements, as well as 18 small mutations identified in the same patient series by SSCP analysis of several exons. After systematic analysis of all 51 exons of COL4A5, we have now identified 30 different mutations: 10 glycine substitutions in the triple helical domain of the protein, 9 frameshift mutations, 4 in-frame deletions, 1 start codon, 1 nonsense, and 5 splice-site mutations. These mutations were either unique or found in two unrelated families, thus excluding the presence of a common mutation in the coding part of the gene. Overall, mutations were detected in only 45% of individuals with a certain or likely diagnosis of X-linked AS. This finding suggests that mutations in noncoding segments of COL4A5 account for a high number of X-linked AS cases. An alternative hypothesis is the presence of locus heterogeneity, even within the X-linked form of the disease. A genotype/phenotype comparison enabled us to better substantiate a significant correlation between the degree of predicted disruption of the alpha5 chain and the severity of phenotype in affected male individuals. Our study has significant implications in the diagnosis and follow-up of AS patients.

Small pore size microporous membrane oxygenator reduces plasma leakage during prolonged extracorporeal circulation: a case report

Plasma leakage has been regarded as the main technical problem during prolonged extracorporeal circulation (ECC) with microporous membrane oxygenators (MMOs). We report the case of a 15 year old male who underwent long term ECC for ARDS and in whom, by using new MMOs with reduced pore size, we were able to achieve prolonged artificial gas exchange efficiency with minimal plasma leakage. We conclude that reduced pore size MMOs might represent a valuable technical advance in extracorporeal oxygenation therapy.

Nephrotic syndrome in a mother and her infant: relationship with cytomegalovirus infection

This case report describes infantile nephrotic syndrome (NS) in a baby girl with a clinically severe cytomegalovirus (CMV) infection. Culture of the baby's urine was positive for CMV and IgM anti-CMV antibodies were detected. After an unsuccessful course of corticosteroids, gancyclovir treatment was started and a remission of cutaneous, pulmonary, and renal symptoms was achieved. As the mother also developed NS at the end of pregnancy, a common etiology could be postulated, although there were no signs of recent CMV infection in the mother, only anti-CMV IgG. The relationship between CMV infection and glomerular disease is still unclear; NS may represent another manifestation of CMV disease.

Multicentre evaluation of Capture Assay Radim Liquid Allergen for measurement of specific IgE antibodies

A multicentre trial of Capture Assay Radim Liquid Allergen was performed to define the sensitivity, specificity and clinical reliability of the system in diagnostic allergology. The results of the evaluation were compared with clinical data and in vivo testing. Good agreement was obtained for Dermatophagoides pteronyssinus (D1), Cat's epithelium (E1), Betula verrucosa (T3) and Olea europea (T9), Artemisia vulgaris (W6) and Parietaria officinalis (W19). Some spreading of data was observed for Artemisia absinthium (W5), Cynodon dactylon (G2), and Lolium perenne (G5). We found a high number of negative cases for Alternaria alternata (M6). The advantages offered by the system are the automation, the small quantity of serum requested, the supply of quantitative results in international units of specific IgE, the user-friendly software. The data are sufficiently reliable for the diagnostic system to be introduced into the clinical laboratory allergological routine.

Glomerulopathy associated with predominant fibronectin deposits: a newly recognized hereditary disease

A newly recognized type of familial glomerulopathy observed in patients of both sexes in six families is reported. Proteinuria, often within the nephrotic range, microscopic hematuria, hypertension and a slowly decreasing renal function over several years were common. No underlying systemic diseases were identified. Generally, light microscopy showed enlarged glomeruli with minimal hypercellularity and with extensive deposits in the mesangium and subendothelial space. By electron microscopy, granular deposits with some admixture of fibrils were most common. In one family, the deposits were predominantly fibrillary. Immunoglobulins and complement factors were inconstant or lacking. A main finding was a strong immune reactivity to fibronectin, corresponding to the distribution of the deposits. In one patient, the deposits recurred in a renal transplant. There was no indication of systemic deposition. Abnormalities in the metabolism of circulating fibronectin may play a pathogenetic role in this disease of probably autosomal dominant inheritance.

Renal disease and patient survival in light chain deposition disease

We evaluated retrospectively the presenting clinical features, response to treatment and clinical course of 19 patients with LCDD, 11 of whom had multiple myeloma. At presentation, renal insufficiency was present in 18 patients and proteinuria in 16. Renal biopsy revealed typical LCDD in 16 patients, while in the remaining three LCDD was associated with other abnormal tissue deposits. Extrarenal signs were observed in 12 patients (63%), with the liver, heart and peripheral nerves being the most frequently involved organs. After diagnosis, 18 patients underwent therapy: 2 received steroids alone and 16 were treated with steroids and cytotoxic drugs; 7 patients also underwent plasma exchange. At the end of the first month of treatment renal function improved in 5 patients, worsened in 5 and remained unchanged in 8. All but 3 of the patients continued treatment beyond the first month: 7 patients developed end-stage renal disease, 5 an improvement and 4 a worsening in renal function. No effect on proteinuria was observed. Extrarenal symptoms developed in 4 previously unaffected patients and in 3 others they extended to more organs. Sixteen patients died: 12 during the first year of the follow-up, and 4 at 21st, 34th, 37th and 82nd month of observation. Five patients died from neoplastic cachexia, 4 from hypokinetic cardiopathy, 3 from hemorrhagic complications, 2 from pneumonia and one from unknown cause. Mean patient survival after presentation was 18.1 +/- 20.7 months.(ABSTRACT TRUNCATED AT 250 WORDS)

State of the art of preanalysis in laboratories in Italy performing endocrinological tests

We conducted an inquiry among Italian laboratories regarding the preanalytical phase for endocrinological tests. The form presented two questions: number of analyses per year and use of closed or open system for blood drawing. The laboratories were asked to insert the hormones' names in some boxes representing different materials for endocrinological tests, namely serum from plain tubes and from gel separator tubes, plasma from K3EDTA, Na2EDTA, lithium heparin with or without gel separator, sodium citrate, sodium fluoride and potassium oxalate, and citric acid-citrate-dextrose (ACD), and also the particular mode of storage of specimen, as addition of antiproteolytic substances and use of iced water. The analytes' list included the most common endocrinological assays. The data collected indicate that traditional, syringe-based systems are still widely used in Italy, particularly in private and small and medium-sized public laboratories. Serum is the most often used material for endocrinological tests. A very important finding was the use of gel separator tubes, wider than plan tubes, for obtaining serum. Finally, the laboratories demonstrated very good attention to the preanalytical phase, as judged from particular storage for some delicate analytes.

Long-term predictors of survival in essential mixed cryoglobulinemic glomerulonephritis

We report the clinical outcome of 105 essential mixed cryoglobulinemia (EMC) patients with renal involvement collected throughout 25 years in three renal Units of Milan. The median follow-up was 72 months since renal biopsy and 131 months since the clinical onset of EMC. Patient survival was 49% at 10 years after renal biopsy. Forty-two patients died primarily from cardiovascular and liver disease or infection, whereas 15 patients developed chronic renal failure. Two patients had a complete remission of the disease while 15 had a remission only of renal signs. Thirty-one patients are alive with persistent renal and extrarenal manifestations. Anti-HCV antibodies were retrospectively detected in 34 patients and were present in 85% of them. This variable was not included in the statistical evaluation. At multivariate analysis, age older than 50 years, purpura, splenomegaly, cryocrit levels higher than 10%, C3 plasma levels lower than 54 mg/dl, and serum creatinine higher than 1.5 mg/dl were independent risk factors for death or dialysis. In conclusion, several factors may influence the outcome of patients with EMC nephritis. Markers of disease activity and an impaired renal function can herald a bad prognosis. It should be stressed, however, that only a minority of patients eventually develop renal failure, probably because in the most severe cases patients die earlier.

Cardiologic abnormalities in patients with long-term lupus nephritis

To assess the cardiological status of patients with long-term lupus nephritis we evaluated 30 patients (mean age 43 +/- 11 years) with lupus nephritis lasting from at least 10 years (mean 15 +/- 5 years). At the time of cardiological evaluation the mean plasma creatinine was 132.6 +/- 11.1 mumol/l and in 28 patients lupus had been quiescent for at least 3 years. Fourteen patients (46.6%) showed one or more cardiac abnormalities: 10 had valvular lesions (1 verrucous endocarditis, 9 thickening and stiffness of one or more valves)--4 patients had regional myocardial akinesis as a consequence of a previous cardiac infarct (one had valvular abnormalities too). One patient had pulmonary hypertension probably secondary to pulmonary vasculitis. No patient had pericarditis. These cardiac abnormalities proved to be statistically correlated with the number of ARA criteria (p = 0.045), the number of lupus flares (p = 0.004), the serum levels of cholesterol (p = 0.04) and of triglycerides (p = 0.025) as well as the duration of hypercholesterolemia (p = 0.005) and of hypertriglyceridemia (p = 0.007). In conclusion, in patients with long-term lupus nephritis cardiac lesions are frequent. The main lesions are non-verrucous valvulopathy (probably a consequence of healing verrucous endocarditis) and cardiac infarct (caused by an accelerated atherosclerosis). On the contrary cardiac lesions caused by active lupus as pericarditis, myocarditis and verrucous endocarditis are rare.

Platelet indices in athletes performing a race in altitude environment

Physical activity could modify platelet count and platelet indices. Previous reports showed modifications after exercise linked to type and duration of sports performances. The shortage of studies in this field stems from the crucial methodological problem of EDTA (ethylenediaminetetraacetic acid)-dependent, mean platelet volume modifications: the published data on platelets count and indices were obtained by using a light-scattering system without standardization of the period elapsed from drawing to measurement. We present a study of platelet indices performed in athletes participating in an "extreme" performance, a race of 30 km in altitude (6,700 m of ascents and descents), using standardized measurement by an aperture-impedance instrument transferred in the field. The platelet count and mean platelet volume significantly increased in athletes, whereas platelet distribution width decreased. The mean initial values were 240.6*10(9)/L for platelet count, 8.79 fL for mean platelet volume, and 15.79% for platelet distribution width. The correspondent mean final values were 288.4*10(9)/L, 9.14 fL, and 15.48%. The modifications of platelet count and indices were always in the physiological reference range. The entity and the rapidity of platelet count and indices modifications suggest that the more probable source of variation is the recruitment of noncirculating pools of mature platelets. Strenuous exercise does not show abnormal changes of platelet parameters.