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Biomedical subjects

D Bassetti

Publications and source records attributed to D Bassetti.

At least 37 records · Page 2Linked to original sources

Use of antibiotics in an Italian children's hospital, 1993-1995; clinical and economic considerations.

Antibiotic consumption and expenditure was studied during 1993 and 1995 in G. Gaslini children's hospital, an Italian 400-bed paediatric hospital, to see if any changes in use had occurred. There was an increase in the cost of antibacterial agents from 1993 to 1995, with a decrease in the daily cost of antibiotics and in the consumption of antiviral, antifungal and antiparasitic agents. There was a notable increase in the use of glycopeptides and carbapenems between 1995 and 1993 especially in specialities such as onco-haematology and intensive care. We suggest a basis for an antibiotic management programme aimed at reducing costs while still providing a high standard of care for patients.

Anti-Bacterial Agents↗

Possible malignant transformation of benign lymphoepithelial parotid lesions in human immunodeficiency virus-infected patients: report of three cases.

Benign lymphoepithelial parotid lesions (BLL) are intraparotid pathological changes that are commonly thought to be an early manifestation of human immunodeficiency virus (HIV) infection. It is not well known whether BLL may undergo malignant transformation into B cell lymphoma and may therefore be a sort of precancerous lesion. We report 3 cases of possible malignant transformation of BLL in HIV-infected patients.

Adult↗

Indinavir pharmacokinetics and parmacodynamics in children with human immunodeficiency virus infection.

The indinavir dosage regimen currently used for human immunodeficiency virus (HIV)-infected children is not based on pharmacokinetic data obtained in the target patient population. The purpose of our study was to characterize indinavir pharmacokinetics and pharmacodynamics in HIV-infected children. Eleven children (age range, 9.0 to 13.6 years; weight range, 21.7 to 56.0 kg) receiving indinavir (500 mg/m(2) every 8 h) in combination with lamivudine and stavudine were studied. The correlation of indinavir pharmacokinetic parameters and demographic parameters was evaluated. Also, the pharmacodynamic relationship between parameters of indinavir exposure and parameters of renal toxicity and immunologic recovery was studied. The area under the indinavir concentration-time curve (AUC) and patient body surface area (BSA) showed a significant negative correlation (r = 0.73; P = 0.012). Patients with smaller BSA had excessive indinavir AUC compared to adults. On the other hand, the median minimum drug concentration in plasma (C(min)) was lower than that reported for adults. The maximum indinavir concentration in serum was higher in patients with renal toxicity (5 out of 11 children), but the difference was not statistically significant (15.3 +/- 8.2 versus 9.8 +/- 4.4 mg/liter; P = 0.19). There was a trend toward higher immunologic efficacy in patients with greater indinavir exposure: the time-averaged AUC of the percentage of CD4(+) lymphocytes over the baseline value for patients with indinavir C(min) > 95% inhibitory concentration (IC(95)) was higher than in patients with C(min) < IC(95) (P = 0. 068). Our study suggests that a dose reduction may be appropriate for children with small BSA and that a 6-h dosage regimen may be indicated for a substantial percentage of patients. Due to the low number of patients enrolled in this study, our results should be confirmed by a larger study.

Adolescent↗

Sensitivity and specificity of immunological methods for the detection of anti-topoisomerase I (Scl70) autoantibodies: results of a multicenter study. The Italian Society of Laboratory Medicine Study Group on the Diagnosis of Autoimmune diseases.

BACKGROUND: The ability of immunometric methods to identify anti-topoisomerase I (Scl70) antibodies is controversial. We wished to quantify the performance of the currently available commercial systems for the assay of anti-topoisomerase I antibodies in a large multicenter study. METHODS: Fifty Italian clinical laboratories analyzed 36 serum samples: 27 from individuals with scleroderma/systemic sclerosis, and 9 from a control group. The scleroderma/systemic sclerosis samples were positive in our laboratories by both ELISA and immunoblot (IB), and the control samples were negative. The laboratories used 42 immunoenzymatic (ELISA), 21 IB, 3 counterimmunoelectrophoresis, and 2 dot-blot methods, produced by 23 different manufacturers. RESULTS: We obtained 2389 results. The ELISA methods showed 99.2% specificity and 97.2% sensitivity for detection of anti-Scl70 antibodies. For IB methods, specificity was 97.6% and sensitivity was 96.1%. The Western-blot method had poor analytical specificity (27% false positives for anti-extractable nuclear antigen antibodies other than anti-Scl70). CONCLUSIONS: Excluding Western blots, commercial ELISA and IB reagents as used in clinical laboratories have a sensitivity and a specificity >95% for determination of anti-Scl70 antibodies.

Autoantibodies↗

The relationship between ritonavir plasma levels and side-effects: implications for therapeutic drug monitoring.

OBJECTIVES: To assess whether the neurological or gastrointestinal adverse effects of ritonavir correlate with parameters of ritonavir systemic exposure. METHODS: Peak (Cmax) and trough (Cmin) ritonavir plasma levels were compared in 11 patients experiencing side-effects (group A) versus 10 patients without side-effects (group B). Ritonavir was administered with the following escalation dosing scheme: 300, 400, 500 mg twice a day for 3, 4, and 5 days, respectively, then the full dose of 600 mg twice a day. Blood sampling was done in group A within 24 h of the occurrence of side-effects and in group B after at least 3 days of the full dosage regimen. RESULTS: Both Cmax and Cmax were significantly higher (Mann-Whitney U test) in patients with side-effects. Cmax was [median (interquartile range)] 26.7 (22.7-33.3) mg/l versus 16.2 (13.4-17.0) mg/l (P = 0.001) and Cmin was 12.6 (9.1-13.9) versus 7.5 (4.9-8.6) mg/l (P = 0.002). CONCLUSION: Patients with higher ritonavir concentrations are at a higher risk of experiencing neurological or gastrointestinal side-effects. Individualization of the dosage regimen, e.g. a downward titration of the ritonavir dose in patients with side-effects, guided by plasma level monitoring, may result in a substantial increase in the percentage of patients tolerating ritonavir without increasing the risk of treatment failure as a result of suboptimal systemic exposure.

Adult↗

Specific high-performance liquid chromatography assay for determination of rifabutin plasma concentration following Extrelut column extraction.

A specific, precise and accurate assay for determination of rifabutin in human plasma using Extrelut column extraction was developed and validated. Rifabutin concentrations were calculated with a standard curve ranging from 5 to 800 ng ml(-1). using a split-curve approach. Chromatographic peaks were separated by means of a 5 microm Symmetry Shield RP8 using a KH2PO4 (0.05 M) buffer-acetonitrile mobile phase. Detection wavelength was set at 275 nm. Chromatography was carried out at room temperature (20-25 degrees C). The limit of quantification was 5 ng ml(-1). The recovery was over 71%. The intra-day precision of the assay was 5, 7, and 1% while the inter-day precision was 11.2, 8.1, and 5.8% at concentrations of 30, 150 and 500 ng ml(-1), respectively. The accuracy ranged from 99 to 108%. Forty of the drugs most commonly administered to HIV-positive patients were found not to interfere with the assay. The assay has been used in a comparative study of rifabutin pharmacokinetics in HIV-positive patients with or without wasting syndrome. reserved.

Antibiotics, Antitubercular↗

Pharmacokinetics of rifabutin in HIV-infected patients with or without wasting syndrome.

AIMS: The purpose of the study was to compare the pharmacokinetic parameters of rifabutin obtained in a group of patients without wasting syndrome (NWS) with those obtained in a group with wasting syndrome (WS). METHODS: A single dose of 300 mg rifabutin was administered in the fasting state to the patients in both study groups and blood samples were scheduled to be collected at the following times: 0 (predose), 0.5, 1, 2, 3, 4, 6, 8, 24, 48, 72 and 96 h following administration. Data were analysed using noncompartmental methods. The pharmacokinetic parameters of rifabutin in patients with and without wasting syndrome were compared using the Mann-Whitney U-test. RESULTS: Cmax was 0.34+/-0. 14 mg l-1 in NWS patients and 0.55+/-0.16 mg l-1 (P=0.01) in patients with WS. tmax was 4.2+/-1.5 and 3.3+/-2.3 h (P=0.17) in NWS and WS patients, respectively. The AUCs were similar in the two study groups. V/F was 2905+/-1646 l in NWS patients and 1701+/-492 l (P=0.07) for the WS group. These differences are less pronounced following normalization of V/F to patients body weight (43.7+/-20.1 vs 35.4+/-10.3 l kg-1 ). t1/2,lambdaz tended to be shorter in patients with WS (31.4+/-12.9 vs 46.0+/-23.5 h, P=0.12). CONCLUSIONS: Our study suggests that the pharmacokinetics of rifabutin in patients with wasting syndrome are not altered to a degree that is clinically important.

Adult↗

[Detection of anti-ENA autoantibodies in patients with systemic connective tissue diseases. Analytical variability and diagnostic sensitivity of 4 methods].

This study was designed to assess the analytical sensitivity and rate of agreement between commercial methods and reagents, among the most used in Italy for the detection of autoantibodies to extractable nuclear antigens (ENA). Sixty-eight serum samples from patients with clinically diagnosed systemic rheumatic diseases were aliquoted and distributed to 4 hospital laboratories; three ELISA (Elias, Shield, Inova) and 1 immunoblot method (Euroimmun) were used. Overall agreement between the test reagents, for each anti-ENA specificity, was 69.1% for Ro/SSA, 83.3% for La/SSB, 70.6% for RNP, 73.5% for Sm, 91.1% for Jo1, and 82.3% for Scl70. Lack of specificity (i.e., false positive reactions) was the most important cause of low concordance. When the data were analysed according to the clinical diagnosis, total agreement and specificity improved. However, a significant difference in terms of sensitivity was observed in the SLE group (30 sera) for RNP (positivity ranged from 20% to 43%) and for Sm (from 7% to 37%), and in the Sjögren's syndrome group (13 sera) for anti-La/SSB (from 8% to 38%). Comparable data were obtained for anti-Ro/SSA (from 70% to 77%) both in the SLE and the Sjögren's syndrome group. Sensitivity of all 4 reagents was good in detecting anti-Scl70 autoantibodies in the 8 patients with diffuse systemic sclerosis, as well as anti-Jo1 autoantibody in the 5 polymyositis patients, with a 100% and a 95% agreement, respectively. These data suggest the need of a better standardization of commercial reagents and analytical procedures, and the opportunity that every laboratory should perform anti-ENA determination by at least two different methods, since none of the methods tested was completely reliable in detecting all anti-ENA autoantibody specificities.

Antibodies, Antinuclear↗

Variability between methods to determine ANA, anti-dsDNA and anti-ENA autoantibodies: a collaborative study with the biomedical industry.

This study was performed by the Italian Society of Laboratory Medicine (SIMeL) in order to establish the variability between the different analytical systems currently used in clinical laboratories for the detection of autoantibodies diagnostic of systemic autoimmune disease. Sixteen industrial, and two university laboratories participated in this study which entailed the determination of anti-nuclear (ANA), anti-dsDNA and anti-ENA antibodies in 11 sera from patients with clinically diagnosed systemic rheumatic disease, using reagents produced by these companies and different methodologies (indirect immunofluorescence, immunoenzymatic assay, counterimmunolectrophoresis, immuno and western blotting). We found 93.5% agreement between the methods used for the detection of ANA, 85.2% for anti-dsDNA antibodies, and 86.9% for anti-ENA antibodies. Among the anti-ENA antibodies, regardless of the method used, detection percentages were excellent for anti-RNP and anti-SSB/La (100%), good for anti-SSA/Ro (93%), but unacceptable for the anti-Jo-1 (67%), anti-Scl70 and anti-Sm (47%) antibodies. This further stresses the need for rigorous standardisation of commercial reagents and analytical procedures, as well as the introduction of external quality assessment (EQA) programs, and a complete definition of operative protocols adjusted to the sensitivity and specificity of the various methods.

Antibodies, Antinuclear↗

Isoelectricfocusing and reverse blotting as a diagnostic tool in pediatric HIV infection.

BACKGROUND: Early diagnosis of perinatally acquired HIV-infection is based on either direct HIV detection--by means of viral culture and/or PCR--or anti-HIV antibody detection. However, due to the passive, transplacental passage of maternal immunoglobulin G, antibody detection is nor reliable until 15-18 months of age. In this regard, clonotypic analysis of specific antibodies performed by isoelectricfocusing and reverse blotting (IEF-RB) can be very helpful, as it recognizes possibly different patterns between mother and infant. OBJECTIVES: We used IEF-RB in order to analyze the kinetics of development of anti-HIV antibodies in infants born to seropositive mothers. STUDY DESIGN: Sera from ten mother/infant pairs (all mothers were HIV-infected) were retrospectively analyzed in order to detect different patterns, between mother and infant, in anti-gp120 V3-loop clonotype. RESULTS: We diagnosed the real HIV status of the examined infants no later than month 6 and in one case as early as month 2. CONCLUSIONS: Considering the small size of sample number, these data are preliminary and should be confirmed by larger scale studies. However, they show IEF-RB, when applied to infants born to seropositive mothers, may be useful in evaluating the infants' dynamics of anti-HIV humoral immune response.

Antigens, Viral↗

Recognition of antigenic clusters of Candida albicans by T lymphocytes from human immunodeficiency virus-infected persons.

The fine specificity of the cellular immune response to Candida albicans (i.e., recognition of different antigenic components) between normal controls and human immunodeficiency virus-infected patients in various stages of disease was compared. C. albicans-specific T cells, enriched by antigen stimulation and interleukin-2 expansion, were challenged with antigenic fractions of different molecular weight obtained by SDS-gel fractionation of C. albicans extracts in the presence of autologous mononuclear cells as antigen-presenting cells. Proliferative responses showed similar patterns of reactivity between controls and category A and B seropositive subjects. Category C patients with concurrent C. albicans infections did not give rise to C. albicans-specific T cell lines, confirming the T cell defect. Patients without clinically evident C. albicans infection had a low but broad reactivity pattern of C. albicans-specific T cells. These results suggest that depletion of C. albicans-specific T cells, independent of their fine specificity, occurs along with disease progression.

Adult↗

Expression of HLA class I-specific inhibitory natural killer cell receptors in HIV-specific cytolytic T lymphocytes: impairment of specific cytolytic functions.

Human T lymphocytes have been shown to express inhibitory natural killer cell receptors (NKR), which can down-regulate T cell antigen receptor-mediated T cell function, including cytolytic activity. In the present study, we demonstrate that CD3+NKR+ cells can be identified in HIV-infected patients. HIV-specific cytolytic activity was analyzed in five patients in whom autologous lymphoblastoid B cell lines could be derived as a source of autologous target cells. Phytohemagglutinin-activated T cell populations that had been cultured in interleukin 2 displayed HIV-specific cytotoxic T lymphocyte (CTL) activity against HIV env, gag, pol, and nef in 3 of 5 patients. Addition of anti-NKR mAb of IgM isotype could increase the specific CTL activity. Moreover, in one additional patient, HIV-specific CTL activity was undetectable; however, after addition of anti-NKR mAb such CTL activity appeared de novo. Similar results were obtained by analysis of CD3+NKR+ clones derived from two patients. These data provide direct evidence that CD3+NKR+ cells may include antigen (HIV)-specific CTLs and that mAb-mediated masking of inhibitory NKR may revert the down-regulation of CTL function.

Antibodies, Monoclonal↗

A randomized trial (ISS 902) of didanosine versus zidovudine in previously untreated patients with mildly symptomatic human immunodeficiency virus infection.

In this multicenter study (ISS 902), 554 previously untreated patients with <500 CD4 cells/mm3 and mildly symptomatic human immunodeficiency virus disease were randomized to receive zidovudine or didanosine (ddI). After a mean follow-up of 20 months, 80 patients (40 zidovudine, 40 ddI) had died and 146 had at least one AIDS-defining event (73 zidovudine, 73 ddI). Overall, no difference was found between treatments with respect to progression to AIDS or death. The analysis of relative risk (RR) of progression over time, however, showed an initially minor risk for zidovudine patients and an inversion in the zidovudine-ddI RR in the second and third years of follow-up. Didanosine showed a greater effect on CD4 cell count response. The two drugs confirmed the toxicity patterns already reported in other trials, with a low occurrence of pancreatitis (ddI 1.3%, zidovudine 0.4%). The overall results suggest that, in this population, zidovudine and ddI monotherapies have comparable long-term clinical efficacy and that more powerful regimens should be preferred.

Acquired Immunodeficiency Syndrome↗

Penetration of dapsone into pulmonary lining fluid of human immunodeficiency virus type 1-infected patients.

We studied the penetration of dapsone into the epithelial lining fluid (ELF) of sixteen human immunodeficiency virus type 1-infected patients who had received the drug at a dose of 100 mg twice weekly as primary prophylaxis for Pneumocystis carinii pneumonia. Bronchoscopy, bronchoalveolar lavage (BAL), and venipuncture were performed for each patient at a specific time after administration of the last dose of dapsone. Dapsone concentrations in plasma and BAL were determined by high-performance liquid chromatography. The apparent volume of ELF recovered by BAL was determined by using urea as an endogenous marker. The mean concentrations of dapsone in ELF at 2 h (five patients), 4 h (three patients), 12 h (two patients), 24 h (three patients), and 48 h (three patients) were 0.95, 0.70, 1.55, 0.23, and 0.45 mg/liter, respectively, while concentrations in plasma were 1.23, 0.79, 1.31, 0.83, and 0.18 mg/liter, respectively. Dapsone concentrations in ELF were 76, 79, 115, 65, and 291% of those observed in plasma at the same times, respectively. These data show that dapsone is well distributed into ELF and that a twice-weekly 100-mg prophylactic regimen results in sustained concentrations in this compartment.

Adult↗