S Valverde

Azienda ULSS numero 14 Chioggia, Chioggia, Veneto, Italy

Are you S Valverde?

Claim your profile

Publications (14)17.11 Total impact

  • Article: Evaluation of the GeneXpert assay in the detection of Factor V Leiden and prothrombin 20210 in stored, previously classified samples.
    G Gessoni, S Valverde, F Manoni
    [show abstract] [hide abstract]
    ABSTRACT: In this study, we evaluated the GeneXpert HemosIL Factor II and Factor V assay, an innovative assay for the detection of Factor V Leiden (FVL) and prothrombin G20210A mutation (GPRO). We evaluated 132 patients that were previously classified (with a concordant result) using two commercial real-time PCR assays supplied, by Applied Biosystems and Roche Molecular Biochemicals. The cohort comprised 75 normal subjects, 10 FVL homozygous, 35 FVL heterozygous, 7 GPRO heterozygous, 2 GPRO homozygous and 3 double heterozygous FVL and GPRO subjects. All of the samples were evaluated using the GeneXpert HemosIL Factor II and Factor V assay. All of the samples were correctly identified using the GeneXpert HemosIL Factor II and Factor V assay; therefore, in this patient series, the specificity and sensitivity of the test under evaluation was 1.00. We have shown that the GeneXpert HemosIL Factor II and Factor V assay, a rapid fully automated assay, can accurately characterise the presence of FV G1691A and FII G20210A polymorphisms with specificity and sensitivity that are comparable to other current real-time PCR-based methods. The theoretical advantages of such an assay include improved standardisation across varying healthcare environments, more thorough sample manipulation and reduced human error.
    Clinica chimica acta; international journal of clinical chemistry 04/2012; 413(7-8):814-6. · 2.54 Impact Factor
  • Article: Laboratory diagnosis of renal failure: urine conductivity and tubular function.
    [show abstract] [hide abstract]
    ABSTRACT: Conductivity is a measure of a material's ability to conduct an electric current and it works thanks to movable charges. Conductivity in urine is directly proportional to ionic contents. The aim of this study was to evaluate the significance of urine conductivity by using the Sismex UF-100 analyser in correlations with other surrogate parameters of osmolality and renal diuresis, relative density, electrolytes and creatinine concentration. For this study 140 urine samples were submitted for diagnostic urinalysis to the Clinical Pathology laboratory. Samples were collected from 70 healthy subjects, 42 diabetics with poor metabolic control and significant glicosuria, 28 patients with monoclonal gammopathy of uncertain significance, with significant proteinuria. All the samples were assessed for conductivity (UF-100 Sysmex), relative density (refract meter Zeiss), sodium, potassium, chlorine, creatinine, urea, glucose, protein (Olympus AU-2700). Urine conductivity appears to be related to ionic concentration but not to glucose and/or protein presence. This study results suggest that conductivity determination should be useful in diabetic patients to study the tubular function minimising interferences due to osmotic action of glucose.
    Minerva urologica e nefrologica = The Italian journal of urology and nephrology 04/2009; 61(1):17-20.
  • Article: Comparison between two functional assays to detect factor V Leiden.
    G Gessoni, S Valverde, F Manoni
    International journal of laboratory hematology 03/2009; 32(1 Pt 1):e188-9. · 1.30 Impact Factor
  • Article: High prevalence of HFE gene mutations in hemodialysis patients.
    [show abstract] [hide abstract]
    ABSTRACT: Hemochromatosis (HH) was a common inherited disease characterized by iron overload. This disease is usually the result of mutations in the HLA-linked hemochromatosis gene (HFE). The aim of this study was to evaluate the frequency of HFE mutations in a group of Venetian hemodialysis patients. Sixty-one hemodialysis patients, 62 patients with laboratory findings suggestive for iron overload, 57 repeat blood donors were enrolled in the study. HFE mutations were detected by using a commercial strip assay. In this study only H63D and C282Y mutations were observed. The overall prevalence of HFE mutations was 40.9% among hemodialysis patients, 30.6% among patients with laboratory findings of iron overload and 15.8% among blood donors. A high prevalence of HFE mutation among hemodialysis patients was observed. Prevalence of HFE mutation in this group was 40.9%, significantly higher than results observed among blood donors (15.8%, P<0.005) or among patients with laboratory signs of iron overload (30.6%, P<0.01). These data are, at present inexplicable, and this results need further confirmation.
    Minerva urologica e nefrologica = The Italian journal of urology and nephrology 06/2008; 60(2):81-4.
  • Article: Laboratory assessment of hypercoagulable state. A study in a group of patients with venous thromboembolism born in Chioggia.
    [show abstract] [hide abstract]
    ABSTRACT: Authors performed a Laboratory assessment for thrombophilia risk factors in a group of patients with previous deep venous thrombosis. 123 consecutive patients were considered. The following parameters were investigated by using commercially available methods: PT, aPTT, TT, Fibrinogen, D-Dimer, Anti thrombin 3 (AT), Protein C (PC), Protein S (PS), activated C protein (APC) resistance, Lupus anticoagulant (LA), FV Leiden (G1691a mutation), Prothrombin G20210A mutation, MTHFR mutation (G677T mutation), anti Prothrombin auto-antibodies (PR) IgG and IgM, anti Beta 2 glycoprotein 1 (B2GP1) auto-antibodies IgG and IgM, anti Cardiolipin (CL) auto-antibodies IgG and IgM, homocysteine. In the 123 patients considered we observed: two AT deficiency, one PC deficiencies, one PS deficiency, 60 FV Leiden mutation (six homozygous), 1 Prothrombin gene mutations (heterozygous), 71 MTHFR mutations (15 homozygous). Study of anti phospholipid auto antibodies showed 10 patients positive for LA, 9 for anti CL antibodies (6IgG and 3IgM), 10 for anti B2GP1 antibody (5 IgG and 5IgM), 3 for anti PR antibody (IgG). Thirty nine patients showed hyper homocysteinemia. In our study only 19 patients were free of demonstrable thrombophilia risk factor. In 51 subjects a single risk factor was identified and in 53 multiple (from 2 to 5) risk factors were identified. In our opinion a Laboratory assessment of thrombophilia risk factors after a previous episode of deep venous thrombosis is a diagnostic tool of great importance. As a matter of fact, in our experience, by using a standard analytical panel, it was possible to highlight one or more risk factors in about 85% of the patients considered.
    Minerva medica 05/2007; 98(2):89-93. · 0.90 Impact Factor
  • Article: Biological qualification of blood units: considerations about the effects of sample's handling and storage on stability of nucleic acids.
    [show abstract] [hide abstract]
    ABSTRACT: In transfusional setting introduction of nucleic amplification technique (NAT) for HBV-DNA, HCV-RNA and HIV-RNA in biological qualification of blood units suggest some problems. At first the opportunity to operate on mini-pool, at second the need to store the samples at +4 degrees C. The authors therefore have tried to estimate the impact of these conditions on the operativity of NAT testing in the transfusional setting. The following parameters has been estimated: distribution of viral-load in untreated subjects, stability of nucleic acids during storage at +4 degrees C, stability of nucleic acids after repeated cycles of freezing and defrosting, robustness of the test to the cross-contamination, definition of the detection-limit (95%). Quantitative tests has been performed by using the following kits: Cobas Amplicor HBV Monitor, Cobas Amplicor HCV Monitor, Cobas Amplicor HIV Monitor; the qualitative tests has been performed by using the following kits: Ampliscreen HBV, Ampliscreen HCV 2,0, Ampliscreen HIV 1,5 all supplied by Roche Molecular System (Brancburg, NJ). Results: Viral load in untreated subjects showed wide variation for HBV, HCV and HIV. HBV has been demonstrated much stable to the conservation +4 degrees C also until 168 h while for HCV and HIV a greater decrease of the viral-load was observed. For all and three virus the conservation to +4 degrees C until 72 h does not seem to involve meaningful fall in the viral-load. A remarkable reduction of the viral-load has been observed after five cycles of freezing and defrosting. All the tests showed a good robustness to cross-contamination. The detection-limit (95%) was 8 U/ml for HBV, 21 U/ml for HCV and 27 copy/ml for HIV. Samples for NAT testing, can be stored until 72 h to +4 degrees C without appreciable lowering of the viral-load. Repeated cycles of changes of state should be avoided. The tests showed a good robustness to cross-contamination. NAT tests for biological qualification of blood units had a minimal sensibility around 50 (copy/unit/ml). In our experience the detection-limit (95%) was 21 U/ml for HCV, 27 copies/ml for HIV, 8 U/ml for HBV. The availability of NAT test for HBV-DNA, HCV-RNA e HIV-RNA, sensitive and reliable, together with epidemiological data, suggest the opportunity to place side by side, in the biological qualification of the blood units, to add the tests for HBV-DNA and HIV-RNA to the test for HCV-RNA mandatory by low, in Italy in the biological qualification of blood units.
    Transfusion and Apheresis Science 07/2004; 30(3):197-203. · 1.25 Impact Factor
  • Article: Haemoglobin E in pregnancy. A case report. Diagnosis, familiar study and counselling, follow up until delivery and new-born observation.
    [show abstract] [hide abstract]
    ABSTRACT: Haemoglobin E is a beta chain variant quite common in Southeastern Asia. The case of a gravid Thai woman with a microcytic anaemia is reported. The diagnosis of homozygous haemoglobin E was suspected on the basis of ethnic considerations when analysis of her haemoglobin showed the absence of normal HbA1 and about 100% of a variant Hb with electrophoretic mobility with HbC and HbA2. Identification of the haemoglobin variant was performed by using an association of alkaline electrophoresis on agarose gel, acid electrophoresis on agarose gel, haemoglobin isoelectrofocusing, high performance liquid chromatography. A study of haemoglobin pattern in the partner, parents and siblings was also performed. Pregnancy continued without any problems until the 40th week when a caesarean section was performed due to a difficult labour with foetal distress. The haemoglobin pattern of the new-born was studied at birth and after 1 year; as expected, it was quite normal at birth and a heterozygous condition for HbE was observed after 1 year. HbE, in even heterozygous and homozygous states, gives a mild clinical picture but its association with other haemoglobinopathies, such as a double heterozygous state (i.e. HbE/beta Thalassaemia) gives rise to a severe transfusion dependent thalassaemia syndrome. It is the authors' opinion that only a strict interaction between obstetricians and pathologists is the possible correct answer to the new diagnostic question proposed by a rapidly evolving inter-ethnic society.
    Minerva ginecologica 05/2004; 56(2):155-9.
  • Article: Cytometry in the diagnosis of acute urinary tract infections: one year's experience.
    Scandinavian Journal of Clinical and Laboratory Investigation 02/2004; 64(1):77-80. · 1.38 Impact Factor
  • Article: Assessment of in vitro platelet activation by Advia 120 platelet parameters.
    [show abstract] [hide abstract]
    ABSTRACT: The Advia 120 Hematology System provides new platelet parameters that have been proposed as useful markers of platelet activation. The aim of this study was to investigate platelet parameter variations after adenosine diphosphate (ADP) activation of platelet-rich plasma (PRP) in vitro, with particular interest in the mean platelet component (MPC), which was compared with two well-known degranulation antigens. Changes in platelet parameters that were induced by the activation of PRP with different concentrations of ADP were examined first. The time course of parameter values up to 60 minutes after maximal ADP activation and the relationships between the MPC and P-selectin and granulophysin expression as determined by flow cytometry were then investigated. After 10 minutes of ADP stimulation, the MPC presented a dose-dependent increase. At the maximal ADP concentration, the initial increase of the MPC was followed by a progressive decrease, leading the MPC to become significantly lower with respect to the baseline after 60 minutes of incubation. Significant variations in other parameters are also described. Finally, a negative correlation was found between the MPC change with respect to time 0 and both P-selectin and granulophysin expression. The present study suggests that platelet parameter variation, particular in the MPC, may be used to assess platelet activation in PRPs stimulated by ADP.
    Laboratory Hematology 02/2003; 9(3):132-7.
  • Article: Field evaluation of a second-generation cytometer UF-100 in diagnosis of acute urinary tract infections in adult patients.
    [show abstract] [hide abstract]
    ABSTRACT: The authors evaluated the analytical performance of the Sysmex UF-100 cytometer vs. the diagnosis of urinary tract infections (UTI). We considered 2010 subjects, aged between 18 and 78, 870 males and 1140 females. The majority (90.2%) of the samples were voided urine specimens collected by using the midstream technique. Each sample was subjected to microbiological evaluation (culture + residual antibacterial activity), dipstick tests, UF-100 examination and microscopic observation. In order to obtain a final diagnosis of UTI these laboratory results were taken into consideration together with clinical data and patients' characteristics. The analytical performance of the laboratory tests was obtained by adopting this diagnosis as standard practice. Out of the total 2010 subjects considered a clinical diagnosis of UTI was obtained in 529 cases (26.32%). The UF-100-based screening had sensitivity, 0.94; specificity, 0.93; positive predictive value, 0.83; negative predictive value, 0.98; and correctly classified incidence, 0.93. In our experience the results of the UF-100-based screening show a very good correlation with the diagnosis of acute UTI in adults patients.
    Clinical Microbiology and Infection 11/2002; 8(10):662-8. · 4.54 Impact Factor
  • Article: [Foetal-maternal alloimmunizations in the South-East area of the Venice province].
    [show abstract] [hide abstract]
    ABSTRACT: This study report the results obtained in a retrospective analysis of the foetal-maternal alloimmunizations observed from 1993 to 1999 in the South-East area of the Venice province. The data concerning 17,000 pregnancy observed in this area from 1993-1999 have been collected. For each pregnancy data concerning maternal ABO, Rh, Kk and IAT as well as foetal ABO, Rh, Kk and DAT were available. Further data (mainly antibodies concentration and specificity) were available if a foetal-maternal alloimmunization was detected and if transfusional support was given after the birth. The authors observed 465 alloimmunizations (prevalence 2.7%): 381 (82%) of these were due to an ABO foetal-maternal incompatibility, 23 due to D incompatibility and the other 61 due to other blood groups antigens. Only 6 cases needed transfusional support: 5 exchange transfusion (a patient needed 2 exchanges) and a delayed transfusion. Foetal-maternal alloimmunizations are today a rare but not exceptional event (about 3% of pregnancy), the great majority of these alloimmunizations are due to an ABO incompatibility. Despite the prevention of alloimmunization in D negative women by using Rh immune globulin, anti-D alloimmunization is still observed. A great number of other blood groups antigens are involved in foetal-maternal alloimmunization mainly within the Rh system (CcEe, etc.). In the authors' experience the great majority of foetal-maternal alloimmunizations were clinically silent, only 6 cases (1.3% of patients with a positive DAT) needed transfusional therapy.
    Minerva ginecologica 09/2002; 54(4):333-8.
  • Article: Platelet count and parameters determined by the Bayer ADVIA 120 in reference subjects and patients.
    [show abstract] [hide abstract]
    ABSTRACT: In order to study the behaviour of traditional and new platelet parameters determined by the ADVIA 120 Hematology System, five hundred samples from reference subjects, divided for sex and age, were processed. Significant variations on the basis of sex and age were found. Reference ranges as 95% confidence limits were therefore calculated for each age class, and platelet parameters proved to have specific variations during lifetime. Moreover, one hundred samples from thrombocytopenic patients were processed by the ADVIA 120 System. When compared with those of reference subjects matched for sex and age, all platelet parameters, except mean platelet component (MPC), showed significant differences.
    Clinical & Laboratory Haematology 07/2001; 23(3):181-6. · 1.11 Impact Factor
  • Article: In subjects with antibody to hepatitis C virus a high serum level of interleukin-2 soluble receptor suggests activity of liver disease.
    [show abstract] [hide abstract]
    ABSTRACT: The hepatitis C virus (HCV) is an RNA virus without apparent cytopathic effects, and hepatocellular damage in chronic infection is generally believed to be immune-mediated by cytotoxic T lymphocytes. Activated T cells release the soluble form of the interleukin-2 (IL-2) receptor (sIL-2R) and its concentration is correlated with the degree of lymphocyte activation. We measured sIL-2R in 69 subjects: 24 healthy repeat blood donors (group I), 17 HCV carriers without liver damage (group II) and 28 patients with HCV-related chronic active hepatitis (group III). There was no significant difference between sIL-2R levels in patients of group I (36.5 +/- 14.6 U ml-1) and group II (46.8 +/- 17.4 U ml-1), and the levels for both of these groups were significantly lower than those observed in the patients with active HCV, group III (176.9 +/- 59.5 U ml-1). Hence, among HCV-infected subjects (HCV RNA positive) with persistently normal alanine aminotransferase (ALT) levels, the plasma levels of sIL-2R are normal, but, in patients (HCV RNA positive) with HCV-related chronic active hepatitis there are increased plasma levels of sIL-2R. We conclude that in HCV infection high levels of sIL-2R are related to activity of the disease rather than to virus replication. In patients with HCV-related chronic liver disease, the sIL-2R concentration may be a useful marker of disease activity.
    Journal of Viral Hepatitis 03/1998; 5(2):99-103. · 4.09 Impact Factor
  • Source
    Article: Quantificazione della batteriuria e dei leucociti urinari mediante Sysmex UF-1000i: confronto con la coltura quantitativa
    [show abstract] [hide abstract]
    ABSTRACT: Riassunto Premesse. Le infezioni delle vie urinarie (UTI) sono assai comuni e di conseguenza le urine co-stituiscono il materiale processato più frequente-mente nella diagnostica microbiologica di routi-ne. Il gold standard diagnostico resta la coltura, tuttavia siccome gran parte dei campioni risulta-no negativi è auspicabile l'adozione di un effica-ce metodo di screening al fine di ridurre il nume-ro di esami colturali superflui. Metodi. Abbiamo valutato le performance anali-tiche e diagnostiche di un nuovo citometro urina-rio (Sysmex UF-1000i) in 209 campioni sottoposti ad uro coltura. Abbiamo comparato la conta dei batteri e dei leucociti urinari ottenuta con UF-1000i con i risultati della coltura quantitativa su CLED Agar a diversi cut-off. Risultati. Utilizzando, per la coltura quantitativa su CLED Agar un valore soglia a 10 4 Unità For-manti Colonie (UFC) /mL per UF-1000i abbiamo ottenuto un cut-off di 30 batteri/microlitro e di 18 leucociti/microlitro; mentre utilizzando per la coltura quantitativa su CLED Agar un valore so-glia a 10 5 UFC/mL per UF-1000i abbiamo ottenu-to un cut-off di 125 batteri/microlitro e di 40 leu-cociti/microlitro. I parametri di Sensibilità (SE), Specificità (SP), Valore Predittivo Positivo (VPP), Valore Predittivo Negativo (VPN) sono sempre risultati soddisfacenti. Conclusioni. Gli autori, sulla base dei risultati ot-tenuti nel presente studio ritengono che nelle con-dizioni cliniche in cui si andrebbe ad utilizzare un valore soglia di 10 4 UFC/mL si possa raccoman-dare un cut-off, per UF-1000i di 30 batteri/micro-litro; cut off da portare a 125 batteri/microlitro per le condizioni cliniche ove si utilizzerebbe un valore soglia di 10 5 UFC/mL alla coltura quanti-tativa. La quantificazione dei leucociti urinari, nella diagnosi delle UTI mediante UF-1000i, sem-bra aggiungere poco all'utilizzo della sola batte-riuria. Summary Quantification of bacteriuria and leukocyturia by using the Sysmex UF-1000i in comparison with urine quantitative colture Background. UTI are a quite common disease and so the more common samples tested in routine diagno-stic microbiology laboratory are urine samples. The gold standard for diagnosis is still bacterial culture but a large proportion of samples are negative. Unneces-sary culture can be reduced by an effective screening test. Methods. We have evaluated the analytical and diagno-stic performances of a new urine cytometer, the Sy-smex UF-1000i, in 209 urine samples submitted to our laboratory for culture. We have compared bacteria and leukocytes count performed by using the UF-1000i with CFU quantification on CLED agar to asses the best cut-off values. Results. In comparison with 10*10 4 CFU/mL we obtai-ned a cut-off value of 30 bacteria mL and a cut-off value of 18 leukocytes/µL. In comparison with 10*10 5 CFU/mL we obtained a cut-off value of 125 bacte-ria µL and a cut-off value of 40 leukocytes/µL. Dia-gnostic performances in terms of SE, SP, VPP, VPN were satisfactory. Conclusions. The authors, on the basis of results obtai-ned in this study, suggest, by using the UF-1000i analy-ser as a screening test for UTI, that the cut-off value for bacteria should be 125/µL for clinical conditions in which 10*10 5 CFU/mL are adopted and should be 30/µL for clinical conditions in which 10*10 4 CFU/ mL are adopted. In this study WBC quantification showed little significance in diagnosis of UTI by using UF-1000i.