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D Mattei

Publications and source records attributed to D Mattei.

At least 19 recordsLinked to original sources
PubMed2006

ELISA and LC-MS/MS methods for determining cyanobacterial toxins in blue-green algae food supplements.

The use of natural products as a diet supplement is increasing worldwide but sometimes is not followed by adequate sanitary controls and analyses. Twenty samples of pills and capsules of lyophilised cyanobacteria (blue-green algae), commercialised in Italy as dietary supplements, were found positive at the Vibrio fischeri bioassay. Further analyses with ELISA and LC-MS/MS methods revealed the presence of four microcystin (MC) analogues, MC-LR, -YR, -LA, -RR and two demethylated forms of MC-RR. The highest total microcystin content was 4.5 and 1.4 microg g-1 in pills and capsules, respectively. The ELISA measurements, compared to the LC-MS/MS analyses, showed significantly lower concentrations of microcystins in pills, this confirming a possible ELISA underestimate of mixed microcystins, due to different sensitivities for some toxic analogues.

Aliivibrio fischeri↗
PubMed2006

Microcystin diversity in a Planktothrix rubescens population from Lake Albano (Central Italy).

The cyanobacterium Planktothrix rubescens Anagnostidis & Komarek (previously Oscillatoria rubescens DC ex Gomont) is present in several Italian lakes and it is known to produce cyanotoxins. The dynamics and toxin production of P. rubescens population in Lake Albano, a volcanic crater lake in Central Italy, has been studied for 5 years (January 2001-April 2005). Winter-spring superficial blooms with frequent scums were observed every year. Total microcystin (MC) levels were measured from April 2004 to October 2005 by liquid chromatography-tandem mass spectrometry. MC levels up to 14.2mug/l were measured, with high concentrations found in summer at a 20-25m depth. The intracellular toxin content varied between 1.5 (surface, January 2004) and 0.21pg/cell (surface, May 2004). Six different MCs were detected, the most abundant being two desmethyl-MC-RR isomers. Of the 13 water wells monitored in the Lake Albano area, two of them showed MC contamination during winter, confirming the ability of these toxins to migrate through groundwater towards public water sources. These results highlight the need for further studies on the mobility and fate of these pervasive cyanobacterial toxins.

Bacterial Toxins↗
PubMed2006

NK/T-cell lymphomas 'nasal type': an Italian multicentric retrospective survey.

OBJECTIVE: To evaluate the clinical characteristics and outcome of NK/T-cell lymphoma 'nasal type' developed in Italian patients. PATIENTS: Between 1997 and 2004, 26 new cases of NK/T-cell lymphoma 'nasal type' were diagnosed in 10 Italian Hematology institutions. RESULTS: All patients were Caucasian, male/female ratio was 19/7, with a median age of 50 years (range 20-80). In 23 cases presentation at the onset was in the nasal cavity or adjacent structures, in two cases the lymphoma onset with skin lesions was followed successively by rhynopharyngeal dissemination, while the remaining case had bone marrow and lymph node involvement followed by oro-pharyngeal involvement. Regarding the stage of disease: 12 patients were in stage I; six in stage II; eight in stage IV. Diagnosis was based on the finding of a NK/T-cell phenotype at the histological and immunophenotypic examination of oropharyngeal or cutaneous lesions. All patients but one were treated with chemotherapy, alone in nine cases or associated to radiotherapy in 14 cases; two patients had chemotherapy, radiotherapy and surgery, while one patient underwent only surgery. Chemotherapy was anthracycline-based in 17 out of 25 cases. In those patients in whom radiotherapy was performed, radiation dosages ranged between 36 Gy and 47.5 Gy, with a median dosage of 40 Gy. Nine patients (34%) were responsive to the treatments: six patients obtained a complete remission and other three a partial remission. The remaining 17 patients resulted refractory or presented a limited response to therapy. The median disease-free survival was 14 months and the median overall survival time was 9 months. CONCLUSION: The results of this retrospective survey confirmed that NK/T-cell lymphoma 'nasal type' is a very rare lymphoma in the Italian population, and it is characterized by a very bad prognosis. Due to the rarity of this disease, a standardized therapeutic approach is lacking. More data are needed to know the epidemiology of this kind of lymphoma in Europe.

Adult↗
PubMed2005

Multiple resistance of acetolactate synthase and protoporphyrinogen oxidase inhibitors in Euphorbia heterophylla biotypes.

Resistance to acetolactate synthase (ALS)-inhibiting herbicides in Brazil has been documented for six species. The probability to select biotypes of Euphorbia heterophylla (EPPHL) with multiple resistance increases in the same order of magnitude as the use of other herbicides belonging to only one mechanism of action. The objectives of this work were to evaluate the distribution of resistant populations (R) in the states of the Parana and Santa Catarina; to determine the existence of populations of EPHHL with multiple resistance to ALS and PROTOX inhibitors, and to confirm the occurrence of cross resistance to compounds of these mechanisms of action. Seeds of EPHHL of areas with suspected resistance had been sampled in 97 places during 2003. In the greenhouse experiment samples of each population were sprayed with imazethapyr or fomesafen, at only one rate. To identify the resistant ones they were sprayed with different levels of the herbicides imazethapyr and fomesafen. Later they were sprayed with diverse herbicides of the same mechanisms of action to confirm the multiple/cross resistance. There is widespread distribution in the region of populations with resistance to ALS inhibitors. Some biotypes demonstrated resistance to herbicides from the two mechanisms of action. The resistance factor (FR), or the relation of resistance between R and susceptible biotypes, confirms the existence of two biotypes of EPHHL with cross resistance to several herbicides inhibitors of ALS and PROTOX.

Acetolactate Synthase↗
PubMed2003

Successful treatment of Acremonium fungemia with voriconazole.

We report two cases of Acremonium fungemia with proven involvement of the skin and probably of the lung in patients who were both undergoing chemotherapy, one for mantle cell lymphoma and the other for acute lymphoblastic leukemia. Both patients failed amphotericin B deoxycholate treatment and were successfully treated with voriconazole with very mild toxicity.

Acremonium↗
PubMed2002

Voriconazole in the management of invasive aspergillosis in two patients with acute myeloid leukemia undergoing stem cell transplantation.

The management of invasive aspergillosis in patients with hematological malignancies remains controversial. A major problem is how to manage patients who had invasive aspergillosis during remission induction and consolidation therapy and then undergo SCT. Indeed in these patients the mortality rate related to invasive aspergillosis recurrence remains unacceptably high. We report two cases of patients who underwent remission induction for AML, developed invasive aspergillosis during antifungal prophylaxis with itraconazole, failed amphotericin B deoxycholate and liposomal amphotericin B treatment, were successfully treated with voriconazole and eventually underwent SCT with voriconazole prophylaxis without reactivation of invasive aspergillosis.

Adult↗
PubMed2001

Plasmodium falciparum signal sequences: simply sequences or special signals?

The malaria parasite, Plasmodium falciparum, synthesises and exports several proteins inducing morphological and biochemical modifications of erythrocytes during the erythrocytic cycle. The protein trafficking machinery of the parasite is similar to that of other eukaryotic cells in several ways. However, some unusual features are also observed. The secretion of various polypeptides was inhibited when P. falciparum-infected erythrocytes were incubated with Brefeldin A. Immunoelectron microscopy studies revealed substantial morphological changes in the endoplasmic reticulum following exposure of parasitised erythrocytes to the drug. Immunofluorescence studies of Brefeldin A-treated parasites suggest that polypeptide sorting to different intracellular destinations begins at the endoplasmic reticulum. The parasite also secretes polypeptides by a Brefeldin A-insensitive route that bypasses the classical endoplasmic reticulum-Golgi complex pathway.

Animals↗
PubMed2001

Fludarabine in combination with cyclophosphamide or with cyclophosphamide plus mitoxantrone for relapsed or refractory low-grade non-Hodgkin's lymphoma.

BACKGROUND AND OBJECTIVES: We report the activity of two combinations of fludarabine (FLU), one with cyclophosphamide (FLU/CY) and the second with CY plus mitoxantrone (FLU/CY/MITO). The aim of the study was to evaluate the activity and toxicity of these two schedules in patients with non-Hodgkin's lymphoma (NHL). DESIGN AND METHODS: Twenty-two patients with recurrent low grade non-Hodgkin's lymphoma (LGL) received FLU/CY (FLU 25 mg/m(2) days 1 to 3, CY 300 mg/m(2) days 1 to 3), and 31 patients received FLU/CY/MITO (FLU 25 mg/m(2) days 1 to 3, CY 300 mg/m(2) days 1 to 3, mitoxantrone 10 mg/m(2) day 1). Patients received antibiotic oral prophylaxis during all treatments and growth factors (G-CSF) when grade III granulocytopenia (WHO scale) occurred. RESULTS: Of the 53 patients, 31 achieved complete remission (CR) (58%) and 16 partial remission (PR) (30%). Response was similar in both arms of the study. After 3 courses, 77% of patients who achieved CR showed a complete disappearance of disease. Seventy-nine per cent of patients experienced granulocytopenia. Few patients had fever, all without infection. One patient died with fever of unknown origin three months after completion of six courses of treatment. INTERPRETATION AND CONCLUSIONS: Both treatments were seen to be effective in recurrent low-grade NHL. Antibiotic prophylaxis with G-CSF support seems to reduce treatment-related infection.

Adult↗
PubMed2000

Pfsbp1, a Maurer's cleft Plasmodium falciparum protein, is associated with the erythrocyte skeleton.

Antibodies from hyperimmune monkey sera, selected by absorption to Plasmodium falciparum-infected erythrocytes, and elution at acidic pH, allowed us to characterize a novel parasite protein, Pfsbp1 (P. falciparum skeleton binding protein 1). Pfsbp1 is an integral membrane protein of parasite-induced membranous structures associated with the erythrocyte plasma membrane and referred to as Maurer's clefts. The carboxy-terminal domain of Pfsbp1, exposed within the cytoplasm of the host cell, interacts with a 35 kDa erythrocyte skeletal protein and might participate in the binding of the Maurer's clefts to the erythrocyte submembrane skeleton. Antibodies to the carboxy- and amino-terminal domains of Pfsbp1 labelled similar vesicular structures in the cytoplasm of Plasmodium chabaudi and Plasmodium berghei-infected murine erythrocytes, suggesting that the protein is conserved among malaria species, consistent with an important role of Maurer's cleft-like structures in the intraerythrocytic development of malaria parasites.

Amino Acid Sequence↗
PubMed1999

The transport of the histidine-rich protein I from Plasmodium falciparum is insensitive to brefeldin A.

During its intraerythrocytic development, Plasmodium falciparum synthesizes several proteins that are exported beyond its membrane. Some of these secreted antigens are involved in the formation of protuberances or knobs, a major virulence factor, at the erythrocyte membrane. Various secreted malarial polypeptides, the transport of which is sensitive to brefeldin A, are translocated in vitro into dog pancreatic microsomes. We present evidence that the histidine-rich protein I (PfHRPI) is secreted by the parasite via a novel pathway, independent of the ER/Golgi apparatus. The secretion of PfHRPI was not blocked by incubation of parasite cultures at 15 degrees C and 20 degrees C or 37 degrees C in the presence of brefeldin A. PfHRPI was not translocated into microsomes in an in vitro translation-translocation cell-free system. Unlike other polypeptides from eukaryotic cells that bypass the ER/Golgi pathway and do not have a signal peptide, PfHRPI has an atypical signal sequence consisting of 21 amino acids, including eight positively charged residues followed by 11 hydrophobic residues. We also found that the unusually charged PfHRPI signal sequence diverts Exp-1, which is usually exported, away from the translocation machinery of microsomal membranes.

Animals↗
PubMed1999

Novel secretory pathways in Plasmodium?

The secretion of proteins from intraerythrocytic stages of Plasmodium falciparum into the infected host cell is still poorly understood. A recent proposal that two distinct, mutually exclusive, secretory compartments may exist within the parasite cell has received much attention. Denise Mattei, Gary Ward, Gordon Langsley and Klaus Lingelbach here critically discuss the data on which this model is based, and then they address a more general question: to what extent are unusual aspects of protein secretion in Plasmodium unique among eukaryotic cells?

Animals↗
PubMed1999

Limited genetic diversity of Plasmodium falciparum in field isolates from Honduras.

The genetic diversity displayed by Plasmodiumfalciparum field isolates, the occurrence of variant forms of the parasite at different frequencies in different geographic areas, and the complexity of the infections represent major obstacles for the development of effective malaria control measures. However, since most of the existing studies have been performed in regions where P. falciparum transmission is high, little is known about the diversity and complexity of parasite populations circulating in areas of low malaria endemicity. We investigated the extent of genetic polymorphism in P. falciparum field isolates from Honduras, a region where its transmission is low and seasonal. Allelic diversity was analyzed in the highly polymorphic parasite genes encoding the merozoite surface proteins- (MSP-1) and -2 (MSP-2) and the glutamate-rich protein (GLURP) by the polymerase chain reaction. Gene polymorphism was also assessed in the EB200 region derived from the highly size polymorphic Pf332 gene. Limited size polymorphism was detected in all genes analyzed, with four and three variants for the MSP-1 and MSP-2 alleles, respectively, and two size variants for the GLURP and Pf332 genes. Moreover, based on the studied genetic markers, most infections consisted of only a few genetically distinct parasite clones. These results suggest that the P. falciparum parasite populations circulating in this region are genetically homogeneous and point to an association between the extent of parasite genetic diversity and the intensity of malaria transmission.

Alleles↗
PubMed1998

Expression and cellular localization of Trypanosoma cruzi type II DNA topoisomerase.

Topoisomerases are enzymes that participate in many cellular functions involving topological manipulation of DNA strands. There are two types of topoisomerases in the cell: (a) type I topoisomerases; and (b) type II topoisomerases (topo II). Previously we have cloned and sequenced the gene encoding Trypanosoma cruzi topo II (TcTOP2). This study group has raised an antiserum against recombinant type II DNA topoisomerase (TctopoII) to study the expression of this gene during T. cruzi differentiation and to determine the cellular location of the enzyme. Western blot analysis showed that T. cruzi TctopoII is expressed in the replicative epimastigotes but not in the infective and non-replicative trypomastigotes. However, slot blot analysis of RNAs extracted from epimastigotes and metacyclic trypomastigotes showed that the mRNA encoding the enzyme is present in both developmental stages of the parasite. Confocal laser microscopy using the antiserum raised against recombinant TctopoII showed that the enzyme is located exclusively in the nucleus of the parasite. Similar results were obtained by immunofluorescence analysis of Crithidia fasciculata. However, monoclonal antisera against the corresponding enzyme extracted from C. fasciculata recognizes a kinetoplast protein in both T. cruzi and Crithidia.

Animals↗
PubMed1998

Characterisation of PfSec61, a Plasmodium falciparum homologue of a component of the translocation machinery at the endoplasmic reticulum membrane of eukaryotic cells.

Plasmodium falciparum secretes several proteins that cause changes in the erythrocyte membrane enabling it to survive within red blood cells. Little is known of the mechanisms involved in the secretion and targeting of parasite polypeptides to the various cell compartments. The P. falciparum gene homologous to the mammalian Sec61alpha, gene, which encodes a component of the translocation pore in the endoplasmic reticulum of eukaryotic cells, was characterised to investigate the translocation process in the parasite. PfSec61 is present as a unique copy in the parasite genome and was mapped to chromosome 13. It encodes a 40 kDa polypeptide, as shown by immunoblotting and immunoprecipitation of [35S]methionine metabolically-labelled parasite extracts. The deduced amino acid sequence of PfSec61 is 87% similar to the mammalian polypeptide, and the two proteins give similar hydropathy plots. These results strongly suggest that PfSec61 has the same topological orientation and functional role as Sec61alpha. Anti-PfSec61 antibodies were used to investigate the cellular location and kinetics of expression of the polypeptide in the parasite. Immunofluorescence confocal microscopy showed that PfSec61 was located in the parasite cytoplasm, close to the nucleus, in a position consistent with its being in the endoplasmic reticulum.

Amino Acid Sequence↗
PubMed1998

Biology of giant proteins of Plasmodium: resolution on polyacrylamide-agarose composite gels.

The malaria parasite Plasmodium falciparum that infects humans encodes several extremely large proteins with molecular masses in the hundreds of thousands to megadalton range. Studies on the structure, function and antigenicity of these ;giant proteins' are hindered by the inability to resolve them effectively in conventional polyacrylamide gels. In this report, Jochen Wiesner, Denise Mattei, Artur Scherf and Michael Lanzer describe a convenient gel system, based on a composite polyacrylamide-agarose matrix, which facilitates analysis of giant proteins.

Journal Article↗
PubMed1997

Humoral immune response to the 72 kDa heat shock protein from Plasmodium falciparum in populations at hypoendemic areas of malaria in western Brazilian Amazon.

The heat-shock protein Pf72/Hsp70-1 from the human malaria parasite Plasmodium falciparum has been suggested as a potential candidate antigen for a multivalent vaccine. We have investigated the prevalence and levels of IgG antibodies to the recombinant protein PfR44, derived from Pf72/Hsp70-1, in individuals from different age groups living in Candeias do Jamari, an Amazonian town characterized by unstable and hypoendemic malaria transmission. Blood were collected from a household-based random sample comprising 241 people and the sera were comparatively tested against recombinant antigen PfR44 and a detergent-soluble extract of P. falciparum (PfAg-T). The prevalence and levels of IgG antibodies to both recombinant and total P. falciparum antigens were positively correlated with cumulative exposure to malaria, as estimated by the age of the individuals and the duration of their stay in the study area. Nevertheless, correlations between antibody responses to Pf72/Hsp70-1 and the acquisition of protective anti-malarial immunity could not be derived from our data.

Adolescent↗