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Biomedical subjects

A Castagna

Publications and source records attributed to A Castagna.

At least 19 recordsLinked to original sources
PubMed2003

Early production and scavenging of hydrogen peroxide in the apoplast of sunflower plants exposed to ozone.

The present work set out to define the processes involved in the early O3-induced H2O2 accumulation in sunflower plants exposed to a single pulse of 150 ppb of O3 for 4 h. Hydrogen peroxide accumulation only occurred in the apoplast and this temporally coincided with the fumigation period. The inhibitor experiments suggested that both the plasma membrane-bound NAD(P)H oxidase complex and cell-wall NAD(P)H PODs contributed to H2O2 generation. To investigate the mechanisms responsible for O3-induced H2O2 accumulation further, both production and scavenging of H2O2 were investigated in the extracellular matrix after subcellular fractionation. The results indicated that H2O2 accumulation is a complex and highly regulated event requiring the time-dependent stimulation and down-regulation of differently located enzymes, some of which are involved in H2O2 generation and degradation, not only during the fumigation period but also in the subsequent recovery period in non-polluted air. Owing to the possible interplay between H2O2 and ethylene, the time-course of ethylene emission was analysed too. Ethylene was rapidly emitted following O3 exposure, but it declined to control values as early as after 4 h of exposure. The early contemporaneous detection of increased ethylene and H2O2 levels after 30 min of exposure does not allow a clear temporal relationship between these two signalling molecules to be established.

Cell Membrane↗
PubMed2002

Successful treatment of a complicated case of neuroleptic malignant syndrome.

Neuroleptic malignant syndrome (NMS) is a life-threatening reaction often related to neuroleptic drugs, characterized by rigidity, hyperthermia, altered consciousness, and fluctuating blood pressure. We present a case of NMS that followed a doubled oral dose of a drug compound: tranylcypromine sulfate, a monoamine oxidase inhibitor, and trifluoperazine (neuroleptic). The case was complicated by rhabdomyolisis and disseminated intravascular coagulation. It was treated successfully with dantrolene sodium and generous fluid therapy without using neuromuscular blocking agents or dopamine agonists.

Administration, Oral↗
PubMed2002

Long-term response in patients receiving HAART including nelfinavir: experience from two Italian centers.

Many studies have demonstrated that the long-term, virological, immunological and clinical effectiveness of highly active antiretroviral therapy (HAART) is mainly related to durable suppression of viral replication. Among the specific antiretroviral agents available today, nelfinavir has been widely used in the last 3 years. This open label, non comparative, retrospective study on 307 patients living with HIV aimed to evaluate the effectiveness of an antiretroviral (ART) regimen including nelfinavir as first-line HAART in terms of rate and durability of viro-immunological response. Most patients, 258/307 (84%), were pre-treated whereas only 49/307 (16%) were treatment naive. The median baseline CD4 cell count was 223 cells/mm3 for naive patients and 317 cells/mm3 for experienced patients whereas median HIV RNA values were 2,500 and 82,000 copies/ml for experienced and naive patients respectively. Median times spent on nelfinavir were 839 and 897 days for experienced and naive patients respectively, with 171/258 pre-treated patients (66%) remaining on nelfinavir-based therapy up to 24 months. Overall, the mean CD4 increase was 196 cells/mm3 with a relevant increment of 165 in experienced patients and 367 cells/mm3 in naive patients (p<0.01). The mean viral load variation in naive patients was -2.22 log10 and in experienced patients -0.53 log10 (p<0.01). In conclusion, nelfinavir, as part of HAART, demonstrated long-term benefit (almost two-thirds of patients stayed on nelfinavir up to 24 months). The response rate in patients naive to antiretroviral therapy was better than for experienced patients. Although there were some differences related to the baseline CD4 level, the overall response rate was good, supporting the role of nelfinavir in HAART.

Adolescent↗
PubMed2001

pH-dependent prion protein conformation in classical Creutzfeldt-Jakob disease.

In transmissible spongiform encephalopathies, the cellular prion protein (PrP(C)) undergoes a conformational change from a prevailing alpha-helical structure to a beta-sheet-rich, protease-resistant isoform, termed PrP(Sc). PrP(C) has two characteristics: a high affinity for Cu(2+) and a strong pH-dependent conformation. Lines of evidence indicate that PrP(Sc) conformation is dependent on copper and that acidic conditions facilitate the conversion of PrP(C) --> PrP(Sc). In each species, PrP(Sc) exists in multiple conformations, which are associated with different prion strains. In sporadic Creutzfeldt-Jakob disease (sCJD), different biochemical types of PrP(Sc) have been identified according to the size of the protease-resistant fragments, patterns of glycosylation, and the metal-ion occupancy. Based on the site of cleavage produced by proteinase K, we investigated the conformational stability of PrP(Sc) under acidic, neutral, and basic conditions in 42 sCJD subjects. Our study shows that only one type of sCJD PrP(Sc), associated with the classical form, shows a pH-dependent conformation, whereas two other biochemical PrP(Sc) types, detected in distinct sCJD phenotypes, are unaffected by pH variations. This novel approach demonstrates the presence of three types of PrP(Sc) in sCJD.

Blotting, Western↗
PubMed2001

Relation between CD4 cell counts and HIV RNA levels at onset of opportunistic infections.

OBJECTIVE: To evaluate the relation between CD4 and HIV RNA levels at the onset of specific opportunistic infections (OIs) in HIV-infected patients. DESIGN AND METHODS: The OIs occurring between June 1996 and December 1998 were retrospectively reviewed, considering only the episodes of major and minor OIs in patients with simultaneously available CD4 and plasma HIV RNA determinations before clinical onset who had been untreated or on stable antiretroviral therapy (ART) for at least 2 months. RESULTS: Two hundred seventy-four episodes of different OIs were considered in 216 patients; the median CD4 count was 35 cells/mm3 (range: 0-1154 cells/mm(3)), and the median HIV RNA count was 5.1 log cp/mL (range: < 1.9-6.7 log copies/ml). The different HIV RNA levels were significantly associated with different OIs regardless of CD4 and ART (p < .0001), even when only those occurring in patients with a CD4 count of < or = 50 cells/mm(3) were considered (p = .0049). Kaposi sarcoma, esophageal candidiasis, oropharyngeal candidiasis, and Mycobacterium avium complex disease were associated with significantly above-average median HIV RNA levels, and varicella-zoster virus infection was associated with below-average levels. CONCLUSIONS: Different OIs are associated at their onset with significantly different HIV RNA levels, regardless of CD4 cell counts and ART.

AIDS-Related Opportunistic Infections↗
PubMed2001

Reversal of CSF positivity for JC virus genome by cidofovir in a patient with systemic lupus erythematosus and progressive multifocal leukoencephalopathy.

We report the case of a 36-year-old woman affected by systemic lupus erythematosus who developed rapidly progressive multifocal leukoencephalopathy. Cidofovir therapy induced disappearance of JC virus genome from the cerebrospinal fluid and stabilization of the MRI picture. Despite the fatal outcome after a few months of disease, cidofovir treatment deserves further testing as single antiviral therapy in HIV-negative PML patients.

Adult↗
PubMed2001

Iron deficiency differently affects peroxidase isoforms in sunflower.

The response of both specific (ascorbate peroxidase, APX) and unspecific (POD) peroxidases and H(2)O(2) content of sunflower plants (Helianthus annuus L. cv. Hor) grown hydroponically with (C) or without (-Fe) iron in the nutrient solution were analysed to verify whether iron deficiency led to cell oxidative status. In -Fe leaves a significant increase of H(2)O(2) content was detected, a result confirmed by electron microscopy analysis. As regards extracellular peroxidases, while APX activity significantly decreased, no change was observed in either soluble guaiacol or syringaldazine-dependent POD activity following iron starvation. Moreover, guaiacol-dependent POD activity was found to decrease in both ionically and covalently-cell-wall bound fractions, while syringaldazine-POD activity decreased only in the covalently-bound fraction. At the intracellular level both guaiacol-POD and APX activities underwent a significant decrease. The overall reduction of peroxidase activity was confirmed by the electrophoretic separation of POD isoforms and, at the extracellular level, by cytochemical localization of peroxidases by diaminobenzidine staining. The electrophoretic separation, besides quantitative differences, also revealed quantitative changes, particularly evident for ionically and covalently-bound fractions. Therefore, in sunflower plants, iron deficiency seems to affect the different peroxidase isoenzymes to different extents and to induce a secondary oxidative stress, as indicated by the increased levels of H(2)O(2). However, owing to the almost completely lack of catalytic iron capable of triggering the Fenton reaction, iron-deficient sunflower plants are probably still sufficiently protected against oxidative stress.

Ascorbate Peroxidases↗
PubMed2000

Redox state and peroxidase system in sunflower plants exposed to ozone.

Sunflower plants subjected to a short-term fumigation with O(3) (150 ppb for 4 h repeated for 4 days) exhibited an increase in total ascorbate content, accompanied by a marked oxidation of ascorbate, leading to a decrease in its redox state, either at intracellular or extracellular level. O(3) exposure induced a rise in free extracellular peroxidase (POD) activity, assayed by syringaldazine as electron donor, as well as in the ionically and covalently cell wall bound PODs. On the contrary, the activity of both extracellular and intracellular guaiacol-POD did not show significant changes as a consequence of the pollutant exposure. The stimulation of syringaldazine-POD activities may be related to the effect of ozone on the growth of the cells, inducing an early senescence through the activation or acceleration of lignification processes. Beside, the reduced plasticity of the cell wall may oppose an unspecific mechanical resistance against the abiotic stress induced by the ozone exposure.

Journal Article↗
PubMed2000

Role of brain biopsy in the management of focal brain lesions in HIV-infected patients. Gruppo Italiano Cooperativo AIDS & Tumori.

In this multicenter, retrospective study of 160 brain biopsies in the assessment of HIV-related focal brain lesions, diagnostic sensitivity was acceptable (87%), but the procedure carried considerable morbidity (7.5%) and mortality (3.1%). Moreover, it is not always possible to initiate the changes in therapy indicated by the results, and overall survival remains poor, with a median of 2 months. Criteria for brain biopsy for the diagnosis of focal brain lesions should be redefined to include selected patients for whom a less invasive approach does not yield a definitive diagnosis.

Adult↗
PubMed1997

Detection of hepatitis C virus genomic sequences in the cerebrospinal fluid of HIV-infected patients.

To assess the presence of hepatitis C virus (HCV) in the central nervous system (CNS), HCV-RNA was sought in paired serum and cerebrospinal fluid (CSF) samples of 21 HIV/HCV-positive patients: HCV-RNA was detected in the serum of 19/21 patients (90.4%), and in the CSF of five of the 19 serum-positive patients. The presence of HCV-RNA was confirmed in follow-up CSF samples available for three of these five patients. An identical HCV genotype was found in the paired serum/CSF samples. No correlation was found between the different genotypes and the presence of HCV in CSF of the individual patients. HCV viremia levels measured by branched-DNA and quantitative PCR were not significantly higher in the CSF-positive cases than in the CSF-negative cases (P = 0.3, using b-DNA; 0.5, using quantitative PCR). This report shows the presence of HCV in CSF and raises the possibility that the CNS may act as a reservoir site for HCV.

AIDS-Related Opportunistic Infections↗
PubMed1997

A comparison of brain biopsy and CSF-PCR in the diagnosis of CNS lesions in AIDS patients.

Twenty patients with AIDS who had intracranial lesions underwent both brain biopsy and cerebrospinal fluid (CSF) examination to compare histological diagnosis with the polymerase chain reaction (CSF-PCR) for the identification of infectious agents. CSF-PCR was performed for herpes simplex virus, varicella zoster virus, cytomegalovirus (CMV), JC virus (JCV), Epstein-Barr virus (EBV), Toxoplasma gondii and Mycobacterium tuberculosis. A definitive diagnosis was obtained by brain biopsy in 14 patients (2 with astrocytoma, 12 with brain infection). CSF-PCR was positive for EBV DNA in 3 of 3 cases of primary cerebral lymphoma, positive for JCV DNA in 6 of 7 biopsy-proven (and one autopsy-proven) cases of progressive multifocal leukoencephalopathy (PML). CSF-PCR was positive for CMV DNA in one biopsy-proven and one autopsy-proven case of CMV encephalitis (the former also had PML) and positive for M. tuberculosis DNA in one case of tuberculous encephalitis. None of the five toxoplasmic encephalitis cases (one definite, four presumptive) were T. gondii DNA positive. There was close correlation between histology and CSF-PCR for CMV encephalitis, PML and PCL. Antitoxoplasma therapy affected the sensitivity of both histological and CSF-PCR methods.

AIDS Dementia Complex↗
PubMed1997

Use of polymerase chain reaction assays of aqueous humor in the differential diagnosis of retinitis in patients infected with human immunodeficiency virus.

We performed polymerase chain reaction (PCR) for detection of cytomegalovirus (CMV), varicella-zoster virus (VZV), herpes simplex virus (HSV), and Toxoplasma gondii DNA in aqueous humor from 15 patients who were infected with human immunodeficiency virus (HIV) and who had retinitis of unclear origin; these patients were selected from among 820 patients evaluated by ophthalmoscopic examination. On the basis of the final response to treatment, CMV, VZV, and T. gondii retinitis was diagnosed in 5, 2, and 4 of the 15 patients, respectively. No final etiologic diagnosis was reached for four patients. All 5 patients with CMV retinitis were CMV DNA-positive. 1 of 2 patients with VZV retinopathy were VZV DNA-positive, and 3 of 4 patients with T. gondii retinitis were T. gondii DNA-positive. All PCR assays of aqueous humor from the four patients without infectious retinitis were negative. PCR assay of aqueous humor is helpful in the etiologic diagnosis of retinitis of unclear origin in HIV-infected patients.

Aqueous Humor↗
PubMed1997

Diagnostic accuracy and predictive value of 201T1 SPET for the differential diagnosis of cerebral lesions in AIDS patients.

The use of 201T1 has been proposed for the differential diagnosis of lymphomas and non-neoplastic brain masses in AIDS patients. The aim of this study was to assess the diagnostic accuracy of three different semi-quantitative methods for the analysis of 201T1 SPET brain images in individuals with AIDS and brain lesions. Thirty-seven AIDS patients with contrast-enhancing brain lesions underwent 201T1 SPET. Three different lesion-to-background uptake indices were calculated: (1) small lesion/large background (SL/LB; i.e. counts in a 3 x 3 pixel ROI in the lesion/counts in a 7 x 7 pixel ROI in the contralateral healthy hemisphere); (2) small lesion/multiple small background (SL/MSL; i.e. counts in a 3 x 3 pixel ROI in the lesion/average counts of ten 3 x 3 ROIs over the highest background pixel values); (3) large lesion/large background (LL/LB; i.e. counts in an elliptic ROI in the lesion/counts in a contralateral mirrored ROI). Data analysis included a ROC curve analysis to identify the cut-off value corresponding to the highest accuracy value, and an analysis of the predictive value to classify the patients in three categories (high, intermediate and low risk of lymphoma). The greatest accuracy (71%) was achieved with the LL/LB method of analysis. Using this method, 62% of patients could be classified as either having lymphoma or not, whereas 38% could not be classified. LL/LB values > or = 2.9 are suggestive of the presence of lymphomas, whereas values < or = 2 are highly predictive of the presence of a lesion other than lymphoma. However, LL/LB values between 2 and 3 are not diagnostic and adjunctive tests should be carried out. In conclusion, 201T1 SPET was an adequate diagnostic tool in approximately 70% of the cases in this study.

AIDS-Related Opportunistic Infections↗
PubMed1997

Use of hybridization assay and direct immuno assay for detection of Salmonella spp. in surface waters and a comparison with conventional culture procedure.

Hybridization assay and direct immunoassay for detecting Salmonella in contaminated surface waters have been compared with the conventional culture procedure. The 67 samples examined were taken from different rivers in the provinces of Catania and Ragusa. By culture method, Salmonella was isolated in 23 samples (34%), while direct immunoassay revealed the presence of Salmonella in 58 samples (87%) and the hybridization method identified Salmonella in 20 samples (30%). On the basis of the results obtained, the direct immunoassay method proved to be inaccurate for the high number of false positives revealed. The DNA probe test gave almost identical results to those obtained with the culture method, with notably shorter execution times than the latter. This test proved to be both sensitive and specific and could be used for the direct demonstration of Salmonella in surface waters where it is easier to find bacteria under stress from the environmental conditions, in waters where isolation is difficult, and in all those environmental control conditions which do not require isolation and the serological typing of the strains of Salmonella.

DNA, Bacterial↗