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BACKGROUND: Rhinitis and asthma represent the manifestation of one syndrome. Our hypothesis is that in patients with symptoms of persistent rhinitis, lower airway inflammation, lower respiratory symptoms, and lung function abnormalities compatible with asthma are more frequently associated with the diagnosis of allergic rhinitis (AR) and chronic rhinosinusitis (CRS) than with nonallergic rhinitis (NAR). METHODS: One hundred eight of 590 consecutive patients referred in 1 year for rhinitis were enrolled on the basis of nasal symptoms lasting > 4 weeks. Asthma was diagnosed on the basis of symptoms and a positive bronchodilation testing result and/or methacholine hyperresponsiveness. Exhaled nitric oxide (Feno) was measured with the single exhalation method at 50 mL/s. RESULTS: AR was diagnosed in 39%, NAR in 21%, and CRS in 40%. The prevalence of asthma was significantly higher in AR patients (33%) and CRS patients (42%) than in NAR patients (8.7%) [p = 0.036 and p = 0.005, respectively]. Feno was significantly higher in patients with AR and CRS compared to patients with NAR (44.3 parts per billion [ppb]; 95% confidence interval [CI], 34 to 54 ppb; and 53 ppb; 95% CI, 42 to 64 ppb; vs 22 ppb; 95% CI, 18 to 27 ppb; p = 0.002 and p = 0.001, respectively). Patients with asthma had Feno values significantly higher than patients without asthma (64 ppb; 95% CI, 51 to 77 ppb; vs 33.3 ppb; 95% CI, 28 to 39 ppb; p < 0.001). CONCLUSIONS: The diagnostic classification of persistent rhinitis helps to predict lower airway inflammation (increased Feno) and prevalence of asthma: AR and CRS are associated with higher mean Feno values and higher prevalence of asthma than NAR. [ABSTRACT FROM AUTHOR]

Primary hyperoxaluria (PH) type 1 and type 2 are autosomal recessive defects of oxalate metabolism resulting from glyoxylate accumulation which occurs by two distinct pathways. PH1 is associated to glycolic aciduria; PH2 to L-glyceric aciduria. Because hyperoxaluria leads to nephrolithiasis or nephrocalcinosis in both, they can be differentiated only through detection of the associated acidurias. However, glycolate and L-glycerate assays are not widely available and, in the setting of ESRF, diagnosis is hampered by a number of misleading events. At any stage of the disease diagnosis is crucial because there are differences between the two forms in clinical behaviour, long-term prognosis, and treatment. In this paper we outline diagnostic criteria for identification of PH2 in two patients, one with maintained renal function and one with ESRF on CPD, based on the use of a novel HPLC assay of L-glycerate in different body fluids. With the routine application of this procedure PH2 has been identified in two of 23 patients fulfilling criteria for diagnosis of PH. This suggests that the type 2 variant of PH may occur more frequently than so far suspected, and should be tested for even in the setting of ESRF. [ABSTRACT FROM PUBLISHER]

Systemic oxalosis is a constant feature in patients with primary hyperoxaluria type 1 (PH1) and chronic renal failure (CRF) and is not prevented by regular dialysis (RDT), because removal cannot keep up with retention and overproduction of oxalate. These patients are candidates to kidney and/or liver transplantation, which should be ideally planned prior to the development of oxalosis. However, methods to detect the presence and extent of oxalosis are invasive and poorly reproducible, and only indirect approaches are feasible. Because supersaturation of body fluids is an essential condition for oxalotic deposits to form, we have assessed serum calcium oxalate saturation (β) in 12 patients with PH1 and 26 with PH1-unrelated renal diseases and varying degrees of CRF. Nineteen healthy individuals were taken as controls. β was closely dependent on oxalate serum levels. Serum oxalate and β were increased in patients with CRF as compared to controls, and were inversely related to GFR, assessed as creatinine clearance. However, at any level of GFR, both were always greater in PH1 patients. From the slopes of the regression of β over CICr, saturation was predicted to be obtained at CICr ranging 24–34 and 8–11 ml/min/1.73 m in PH1 and non-PH1 patients respectively. Based on the dependence of β on oxalate, saturation was associated with serum oxalate between 44 and 46 µmol/l, irrespective of either the prevailing GFR or the underlying disease. These simple procedures represent a valuable non-invasive tool to define the risk of systemic oxalosis and may assist in timing of transplantation. [ABSTRACT FROM PUBLISHER]

Background: Heparin-induced thrombocytopenia (HIT) is a serious adverse effect of heparin treatment caused by platelet-activating anti-platelet factor 4 (PF4)/heparin antibodies. Accurate diagnosis of HIT is essential but remains challenging. The aim of our study was to explore the performance of our optimized diagnostic laboratory algorithm, based on Chemiluminescence (CliA) and ELISA immunoassays, on suspected HIT patients. The study compared the prevalence of HIT diagnosis in A.O. Mauriziano with the literature., Methods: 163 consecutive patients were investigated for suspected HIT with CliA HemosIL Acustar HIT-IgG, Werfen. HIT was ruled out in all patients with CliA <0.13 U/mL. All patients with CliA >0.13 U/mL were further investigated with Zymutest-HIA anti-PF4 IgG ELISA immunoassay. In these patients, HIT was ruled out on the combination of CliA between 0.13 and 1.0 U/mL followed by ELISA assay <0.300 OD. HIT was ruled in patients whose plasma tested positive or doubtful with CliA and positive with ELISA immunoassay and confirmed positive with a platelet aggregation test (PAT). Suspicion of HIT was revealed with clinical 4Ts score or recent suggestive anamnestic history., Results: Our diagnostic algorithm ruled out HIT diagnosis in 144/163 patients (88%) and predicted a positive PAT in 5/19 (26%) of CliA positive (4/5) or ELISA positive and CliA doubtful (1/5) patients., Conclusions: Our prevalence was 3.1%, comparable with the literature. The approach combining 2 quantitative immunoassays' (CliA and ELISA) results and 4Ts score probability was able to rule out the diagnosis within 1 h in 66% of patients with suspected HIT and within 24 h in 88% of patients. In the remaining 12% of cases, management decisions have to be based on individualized judgment while awaiting functional confirming results (48-72 h)., (© Association for Diagnostics & Laboratory Medicine 2024. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Background: Systemic lupus erythematosus (SLE) is a chronic autoimmune disorder characterized by a variety of both signs and symptoms; it mainly affects women of childbearing age, with an estimated prevalence of 24/100,000 people in Europe and North America. SLE is often described as an antibodies-driven disease as its clinical manifestations are usually associated with the presence or the absence of specific antibodies., Objectives: To evaluate clinical manifestations in patients with SLE and to assess the relationship with the presence of specific antibodies by using real-world data., Methods: A retrospective study was performed; the 2019 EULAR/ACR Classification Criteria for Systemic Lupus Erythematosus were used to classify patients with SLE. Data concerning serological profiles (which included Antinuclear antibodies - ANA, anti dsDNA, anti-Ro/SS-A, anti-La/SS-B, anti-Smith) were gathered along with medical records of clinical manifestations. Complement levels were also tested for possible clinical correlations. χ² or Fisher's exact tests were utilized to establish associations between autoantibodies and symptoms. The odds ratios (OR) and their 95% confidence intervals (CI) were computed. No correction was made for multiple testing; only a p-value 0.01 ≤ was considered significant., Results: One-hundred and twenty-seven patients (n=127, mean age 53.43 ± 14.02) were enrolled in this study. Anti-dsDNA antibodies were found to be statistically significant for both malar rash and proteinuria; anti-Ro/SSA antibodies showed an association with photosensitivity and pericarditis; furthermore, a strong association was found between anti-Ro antibodies and proteinuria, but only if anti-dsDNA antibodies were present as well. Patients who tested positive for anti-La/SSB antibodies correlated with a threefold increase in the risk of developing pericarditis. Lastly, anti-Smith appeared to be associated with NPSLE as well as an increased risk for both autoimmune hemolytic anemia and thrombocytopenia., Conclusions: In our study, many associations confirmed those found in previous studies; however, new relationships between antibodies and clinical manifestations were found thus indicating the need for additional evaluations to assess these correlations further., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Nicola, Borrelli, Corradi, Lo Sardo, Badiu, Romito, Rashidy, Quinternetto, Mazzola, Meli, Saracco, Vitali, Cosseddu and Brussino.)

The lateral flow immunoassay (LFIA) technique is largely employed for the point-of-care detection of antibodies especially for revealing the immune response in serum. Visual LFIAs usually provide the qualitative yes/no detection of antibodies, while quantification requires some equipment, making the assay more expensive and complicated. To achieve visual semi-quantification, the alignment of several lines (made of the same antigen) along a LFIA strip has been proposed. The numbering of the reacting lines has been used to correlate with the quantity of some biomarkers in serum. Here, we designed the first semiquantitative LFIA for detecting antibodies and applied it to classify the immune response to SARS-CoV-2 raised by vaccination or natural infection. We used a recombinant spike receptor-binding domain (RBD) as the specific capture reagent to draw two test lines. The detection reagent was selected among three possible ligands that are able to bind to anti-spike human antibodies: the same RBD, staphylococcal protein A, and anti-human immunoglobulin G antibodies. The most convenient detector, adsorbed on gold nanoparticles, was chosen based on the highest correlation with an antibody titre of 171 human sera, measured by a reference serological method, and was the RBD (Spearman's rho = 0.84). Incorporated into the semiquantitative LFIA, it confirmed the ability to discriminate high- and low-titre samples and to classify them into two classes (Dunn's test, P < 0.05). The proposed approach enabled the semiquantification of the immune response to SARS-CoV-2 by the unaided eye observation, thus overcoming the requirement of costly and complicated equipment, and represents a general strategy for the development of semiquantitative serological LFIAs.

Serial measurements of cardiac troponin are recommended by international guidelines to diagnose myocardial infarction (MI) since 2000. However, some relevant differences exist between the three different international guidelines published between 2020 and 2021 for the management of patients with chest pain and no ST-segment elevation. In particular, there is no agreement on the cut-offs or absolute change values to diagnose non-ST-segment elevation MI (NSTEMI). Other controversial issues concern the diagnostic accuracy and cost-effectiveness of cut-off values for the most rapid algorithms (0 h/1 h or 0 h/2 h) to rule-in and rule-out NSTEMI . Finally, another important point is the possible differences between demographic and clinical characteristics of patients enrolled in multicenter trials compared to those routinely admitted to the Emergency Department in Italy. The Study Group of Cardiac Biomarkers, supported by the Italian Scientific Societies Società Italiana di Biochimica Clinica, Italian Society of the European Ligand Assay Society, and Società Italiana di Patolgia Clinica e Medicina di Laboratorio decided to revise the document previously published in 2013 about the management of patients with suspected NSTEMI, and to provide some suggestions for the use of these biomarkers in clinical practice, with a particular focus on the Italian setting., (© 2021 Walter de Gruyter GmbH, Berlin/Boston.)

Background: The SARS-CoV-2 outbreak early in 2020 overwhelmed the Italian national health system, and hospitals were considered places at high risk of spreading the infection. We explored specific antibody seroprevalence of all employees at a single hospital in the epicentre of the outbreak, to identify areas of risk in nosocomial setting and to evaluate the usefulness of antibody testing., Aims: Aim of this study was to explore SARS-CoV-2 seroprevalence in a single hospital workers cohort., Methods: All hospital workers were invited to fill in a questionnaire and undergo a blood test for SARS-CoV-2 IgG, using two commercial tests (DiaSorin and Abbott). Seropositivity was determined overall and according to demographic and occupations characteristics, for both tests singly and combined., Results: The study enrolled 1562 hospital workers (95% of the eligible population). Overall, 153 (9.8%) participants were positive for SARS-CoV-2 IgG on DiaSorin test, and 150 (9.6%) were positive on Abbott test; both tests were positive in 123 (7.9%) cases and at least one was positive in 180 (11.5%) cases. Factors associated with SARS-CoV-2 seropositivity included: being a smoker, working in emergency or medicine departments, being a healthcare practitioner, self-reporting a relative with COVID-19 or symptoms suggestive of COVID-19, and having undergone a nasopharyngeal swab test. The tests were accurate in discriminating infected cases, with an area under the receiver operating characteristic curve of 0.867 using manufacturer-suggested cut-offs and 0.929 using optimised cut-offs. For discriminating symptomatic subjects, this value was 0.915 using optimised cut-offs., Conclusions: Seroprevalence for SARS-CoV-2 in this population of hospital workers was overall about 10%, with an excess prevalence in roles and departments associated with contacts with COVID-19 patients., (© 2021 Royal Australasian College of Physicians.)

The clinical significance of antiphospholipid antibodies (aPL) in the context of infections has attracted attention since their first discovery in patients with syphilis. In fact, the recognition of aPL in patients with infections has been described in parallel to the understating of the syndrome. Since the first description of aPL-positive tests in three patients with COVID-19 diagnosed in January 2020 in Wuhan, China, a large number of studies took part in the ongoing debate on SARS-2-Cov 2 induced coagulopathy, and many following reports speculated a potential role for aPL. In order to get further insights on the effective role of detectable aPL in the pro-thrombotic status observed in COVID-19 patients, we performed an observational age-sex controlled study to compare the aPL profile of hospitalized patients with COVID with those observed in a) patients with thrombotic APS and b) patients with cultural/serologically-proved infections. Our data showed positive aPL testing in about half of the patients (53%) with COVID-19 and patients with other viral/bacterial infections (49%). However, aPL profile was different when comparing patients with overt APS and patients with aPL detected in the contest of infections. Caution is therefore required in the interpretation and generalization of the role of aPL s in the management of patients with COVID-19. Before introducing aPL testing as a part of the routine testing in patients with COVID-19, larger well-designed clinical studies are required. While the pro-thrombotic status in patients with COVID-19 is now unquestionable, different mechanisms other than aPL should be further investigated., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Sciascia, Radin, Bazzan, Montaruli, Cosseddu, Norbiato, Bertero, Carignola, Bacco, Gallo Cassarino and Roccatello.)

Background: Thrombotic thrombocytopenic purpura (TTP) is a life-threatening disorder characterized by severe ADAMTS13 deficiency. The acquired form is associated with autoantibodies directed against ADAMTS13. Both noninhibitory and inhibitory autoantibodies can be detected by ELISA assay, while only inhibitory autoantibodies are detected by Bethesda assay. Due to its short TAT and good performance, chemiluminescence (CliA) ADAMTS13 activity (HemosIL Acustar) has proven to be a good choice in the diagnosis of TTP in emergency settings. Aim of this study was to analyse the performance of the CliA ADAMTS13 activity assay in detecting inhibitory ADAMTS13 antibodies using the Bethesda assay., Methods: A method comparison study was performed on 69 stored samples: 11 acute TTPs, 38 TTP follow-ups, 5 TTP relapses, 1 congenital TTP, 10 HUS, 4 suspected TTPs. We retrieved the results of tests previously run in ELISA for both activity and autoantibodies. At the same time, we reran new tests including ELISA and CliA activity, ELISA autoantibodies, and ELISA and CliA Bethesda assays on thawed frozen samples., Results: Very good correlation was observed between ELISA and CliA activity assay results (r = 0.96) and between archived ELISA and CliA activity results (r = 0.93). Agreement between the anti-ADAMTS13 assays ranged from good (k = 0.63) to very good (k = 0.92)., Conclusions: CliA and ELISA Bethesda assays showed very good agreement with samples run at the same time using ELISA ADAMTS13-autoantibody assay. Albeit more expensive, the CliA Bethesda assay identified inhibitory anti-ADAMTS13 within almost the same TAT as ELISA, but with better automation and limited operator involvement., (© 2020 John Wiley & Sons Ltd.)

: In the coagulation laboratory, spurious hemolysis, icterus and lipemia (HIL) in test samples represent by far the leading diagnostic prenalytical challenges. The aim of this study was to assess the performance of the preanalytical module on the new hemostasis analyser Cobas Roche t511. We assessed the influence of HIL on prothrombin time (PT), activated partial thromboplastin time (APTT), fibrinogen (Fib), antithrombin and D-dimer on plasma pools aliquots with different interference degrees. Moreover, we evaluated spontaneous hemolysis by comparing results on 50 paired samples (hemolysed versus nonhemolysed). Spurious hemolysis interference studies highlight the absence of a clinical significant impact on PT, APTT and antithrombin test results at all hemoglobin concentration investigated. For Fib and D-dimer assays a clinically significant difference was observed in the most hemolysed aliquot for Fib and in the two most hemolysed aliquots for D-dimer. Spontaneous hemolysis interference studies showed no clinical significant differences for PT and antithrombin assays, instead for APTT, Fib and D-dimer we found significant statistical and clinical differences between hemolysed and non hemolysed specimens. Bilirubin interference studies and lipemic samples interference studies enable us to confirm that the differences in the results obtained between the different aliquots and reference pool is not clinically significant for all assays. HIL check preanalytical module of Cobas Roche t511 analyzer displaied excellent performance for routine use in clinical laboratories. Regardless of analytical considerations, the type of interference encountered with spurious HIL is substantially different and requires different approaches.

Background: According to quality specifications required by international guidelines, the evaluation of the 99th URL value is a very difficult task that is usually beyond the capacity of a single laboratory. The aims of this article are to report and discuss the results of a multicenter study concerning the evaluation of the 99th percentile URL and reference change (RCV) of the ADVIA Centaur High-Sensitivity Troponin I (TNIH), recently distributed to the Italian clinical laboratories., Materials and Methods: The reference population evaluated with ADVIA XPT method for the calculation of cTnI reference distribution parameters consisted of 1325 healthy adults subjects (age range from 18 to 86 years), including 653 women (mean age 50.7 years, SD 14.5 years) and 672 men (mean age 50.9 years, SD 13.8 years), well matched for both age (P = .8112) and sex (F/M = 0.97)., Results: cTnI distribution values of reference population was highly skewed, while log-transformed cTnI values roughly approximated a log-normal distribution. Men have higher cTnI values than women throughout all the adult lifespan. Moreover, the subjects with age ≤ 55 years had significantly lower cTnI values than those with age > 55 years (p < .0001). Of note, 62% of women and 77% of men had equal or higher than cTnI values than the LoD value of the method (i.e., 2.2 ng/L)., Conclusions: The results of the present study demonstrate that the ADVIA Centaur High-Sensitivity Troponin I using the XPT automated platform fits both the criteria and quality specifications required by the most recent international guidelines for high-sensitivity methods for cTnI assay., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Background: The Italian Society of Clinical Biochemistry (SIBioC) and the Italian Section of the European Ligand Assay Society (ELAS) have recently promoted a multicenter study (Italian hs-cTnI Study) with the aim to accurately evaluate analytical performances and reference values of the most popular cTnI methods commercially available in Italy. The aim of this article is to report the results of the Italian hs-cTnI Study concerning the evaluation of the 99th percentile URL and reference change (RCV) values around the 99th URL of the Access cTnI method., Materials and Methods: Heparinized plasma samples were collected from 1306 healthy adult volunteers by 8 Italian clinical centers. Every center collected from 50 to 150 plasma samples from healthy adult subjects. All volunteers denied the presence of chronic or acute diseases and had normal values of routine laboratory tests (including creatinine, electrolytes, glucose and blood counts). An older cohort of 457 adult subjects (mean age 63.0 years; SD 8.1 years, minimum 47 years, maximum 86 years) underwent also ECG and cardiac imaging analysis in order to exclude the presence of asymptomatic cardiac disease., Results and Conclusions: The results of the present study confirm that the Access hsTnI method using the DxI platform satisfies the two criteria required by international guidelines for high-sensitivity methods for cTn assay. Furthermore, the results of this study confirm that the calculation of the 99th percentile URL values are greatly affected not only by age and sex of the reference population, but also by the statistical approach used for calculation of cTnI distribution parameters., (Copyright © 2019 The Authors. Published by Elsevier B.V. All rights reserved.)

Dabigatran is an oral direct inhibitor indicated for stroke prevention in patients with atrial fibrillation. Unlike warfarin, dabigatran's observed therapeutic window and minimal drug-to-drug interaction suggest that laboratory test and dose adjustments are not necessary; nevertheless, circumstances of excessive anticoagulation, decreased kidney function, and instances of significant bleeding and thrombosis require laboratory assessment. In order to gather experience in the management of global [activated partial thromboplastin time (APTT) and thrombin time (TT) with extended endpoint] and specific [ecarin chromogenic assay (ECA) and diluted thrombin time (dTT)] laboratory coagulation tests in patients receiving dabigatran with untoward effects, we describe a case in which hemodialysis was used in attempt to remove dabigatran in a patient with excessive anticoagulation, rectal bleeding, and severe anemia. Our experience confirmed that APTT is an unreliable method for the assessment of dabigatran in patients with acute complications because it was often normal in spite of the therapeutic drug plasma levels. Both ECA and dTT showed a linear correlation with dabigatran levels over a broad range, and identified therapeutic and supratherapeutic levels. TT assay, which is highly sensitive to dabigatran, correlated well and linearly not only with low drug levels, but also, because of the introduction of the extended endpoint (400 s), with high concentrations of the drug, and demonstrated to be a simple and reliable alternative to ECA and dTT to assess dabigatran in patients with acute complications.

A 85-year-old man, with CKD (e-GFR 35 mL/min), had been given Dabigatran (a direct thrombin inhibitor) at 110 mg daily dose because of atrial fibrillation. Due to intercurrent diarrhea and dehydration, renal function worsened (e-GFR 11 mL/min) and Dabigatran excretion decreased, thereby inducing drug overload. In this case, Dabigatran must be removed by dialysis, but the most appropriate schedule is still undefined. The effects of both continuous haemodiafiltration (CVVHDF) and intermittent haemodialysis (IHD) on plasma Dabigatran (Echarin Chromogenic Assay) were reported. Dialysis clearance of Dabigatran was reported as ratio to urea clearance (Dab/Urea(Cl)). Coagulation was assessed by both DOA-aPTTratio and Thrombin Time-ratio (TTratio). Dabigatran was elevated at 597 ng/mL predialysis (bleeding threshold being 30 ng/mL), and decreased to 96 ng/mL (-84%) after 20 hours of CVVHDF (Urea(Cl) = 67 mL/min). Dab/Urea(Cl) was 0.49. Three hours after dialysis, Dabigatran rebounded to 208 ng/mL. On IHD (Urea(Cl)=238 mL/min), predialysis Dabigatran was 52 ng/mL and decreased to 8 ng/mL (-85%) after 3.5 hours of treatment. Dab/Urea(Cl) was 0.47. Fourteen hours later, Dabigatran rebounded at 19 ng/mL. There was a positive correlation between Dabigatran and TTratio (r = 0.92; p<0.0001), whereas DOA-aPTT did not increase above 2.5 times the reference values, even in face of the highest values of Dabigatran. Therefore, TTratio is more reliable than DOA-aPTT in detecting Dabigatran overdose. Post-dialysis rebound of Dabigatran occurred also with CVVHDF, thereby suggesting that accurate monitoring of both Dabigatran levels and bleeding risk are mandatory, also after long-lasting dialysis sessions.

Objective: To test the inflammation and oxidative stress hypothesis in antiphospholipid syndrome (APS) patients and to identify possible associations with clinical and laboratory features of the disease., Methods: Serum amyloid A (SAA), C-reactive protein (CRP), 8-isoprostane and prostaglandin E2 (PGE) were assayed in the sera of 45 APS patients and then compared to control groups made up of 15 antiphospholipid antibody (aPL) negative patients with systemic lupus erythematosus, 15 aPL negative subjects with pregnancy-related morbidity, 15 aPL negative patients with thrombosis, 15 subjects with persistently positive aPL with no signs or symptoms of APS, and 15 healthy volunteers from among the hospital staff., Results: APS patients showed significantly higher CRP (p = 0.01), SAA (p < 0.01), 8-isoprostane (p = 0.05) and PGE2 (p = 0.001) plasma levels as compared to controls. Among APS subjects, significantly higher 8-isoprostane and PGE2 levels were observed in patients with triple positivity for aPL (lupus anticoagulant, anticardiolipin and anti-beta2-glycoprotein I antibodies) compared to APS patients with single or double aPL positivity., Conclusion: Both inflammation and oxidative stress, as measured by SAA, CRP, 8-isoprostane and PGE2, occur in APS and seem to be related to triple positivity for aPL.

Specimens were collected from 22 Italian patients with primary hyperoxaluria type 1 (PH1). Ten of them had already been analyzed by molecular biology. To clarify the molecular characteristics of the AGXT gene disease responsible for PH1, DNA samples were examined for known mutations by hybridisation of PCR products with Sequence Specific Oligonucleotides (PCR-SSO). We planned to identify new mutations of the AGXT gene by heteroduplex analysis followed by direct sequencing. We had already standardized a) the conditions for the amplification of the 11 exons of AGXT, b) the PCR-SSO technique and c) the heteroduplex analysis of amplified products. Preliminary results demonstrated that the AGXT mutations described in previous studies were found only in 40% of the examined Italian patients with PH1. The remaining 60% of mutations should be characterised in future studies.

To investigate patterns of monolateral and bilateral nephrolithiasis, we enrolled 196 patients with idiopathic calcium stone disease (ICaSD) and 36 with proven primary hyperparathyroidism (PHP). Monolateral disease occurred in 45 subjects with ICaSD and 3 with PHP. All had had three or more stone events. They were studied for a number of clinical and biochemical parameters. The expected prevalence of monolateral stone disease was calculated according to the binomial distribution of random events. Whereas the observed and expected prevalence of monolateral nephrolithiasis did not differ in PHP, the distribution did not follow a chance pattern in ICaSD, since monolateral disease was still frequent among patient with more than 6 episodes. To find out whether monolateral and bilateral ICaSD had distinct pathogenic mechanisms the two groups were compared for clinical and biochemical patterns: no differences emerged concerning metabolic derangements, urine saturation and diet-related biochemistries. Bilateral stone-formers had a higher recurrence rate, but a similar number of stone-operations or ESWL. In 81 of 151 bilateral idiopathic stone-formers in which we were able to assess the exact number of stone events in left and right kidney, the distribution of stones between kidneys did not differ from the binomial distribution. In conclusion, while PHP-associated nephrolithiasis presents predictable patterns, ICaSD comprises a subset in which the disease occurs monolaterally. These forms cannot be distinguished from bilateral forms with common clinical features or routine biochemistries.

Six patients (3 children and 3 adults) with the clinical and biochemical features of Bartter's syndrome are presented. Pediatric cases included a more severe form, in one patient, with physical and mental retardation, hypercalciuria and nephrocalcinosis, and a less severe one, including two patients, with milder clinical features, low calcium and high magnesium excretion and hypomagnesiemia. Adult patients were affected by either the mild congenital form (case n. 4) or the acquired variety (cases n.5 and 6). Tubular function was investigated in the 3 adults by assessing clearance measurements during maximal diuresis. There was a defective fractional distal solute reabsorption (FDR) ranging between 0.52 and 0.60. This was well below the results obtained in one patient with psychogenous vomiting (FDR 0.94) and comparable to those in two patients with interstitial nephropathies caused by vesico-ureteral reflux (FDR 0.63 and 0.67 respectively). We concluded that: 1) the etiopathogenetic spectrum of Bartter's syndrome corresponds to different clinical presentation (mild, heavy, congenital or acquired varieties), and alterations in mineral and electrolyte renal handling; 2) reduction in FDR is a feature neither essential nor exclusive of this syndrome.