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Biomedical subjects

C Moroni

Publications and source records attributed to C Moroni.

At least 55 records · Page 3Linked to original sources
PubMed1996

Fluconazole versus amphotericin B as empirical antifungal therapy of unexplained fever in granulocytopenic cancer patients: a pragmatic, multicentre, prospective and randomised clinical trial.

Amphotericin B, despite its intrinsic servere toxicity, is the most commonly used empirical antifungal therapy in cancer patients with unexplained fever not responding to empirical antibacterial therapy. The aim of this study was to show whether fluconazole was as effective as, and less toxic than, amphotericin, with no effort made to compare the antifungal activity of the two drugs. A group of 112 persistently febrile (> 38 degrees C) and granulocytopenic (< 1000 cells/mm3) cancer patients, not receiving any absorbable antifungal antibiotic for prophylaxis, with a mean age of 27 years (range 1-73 years), undergoing chemotherapy for a variety of malignancies and with a diagnosis of unexplained fever after at least 96 h of empirical antibacterial therapy, were randomised to receive either fluconazole (6 mg/kg/day up to 400 mg/day) or amphotericin B (0.8 mg/kg/day) as empirical antifungal treatment. Patients were required to have normal chest X-rays at randomisation, no previous history of aspergillosis and negative surveillance cultures for Aspergillus. The intention-to-treat analysis showed defervescence and survival without treatment modification in 42 of 56 patients (75%) in the fluconazole group and in 37 of 56 (66%) in the amphotericin B group (P = 0.4). Duration of therapy was 6 days (95% CI = 4-8 days) in both groups. Death occurred in 3 patients (5%) in the fluconazole and in 2 (4%) in the amphotericin B group. No fungal death was documented in either group. Adverse events developed in 18 of 56 patients (32%) in the fluconazole group and in 46 of 56 (82%) in the amphotericin B group (P < 0.001). In the amphotericin B group, 5 patients had treatment discontinued because of toxicity, versus none in the fluconazole group, a difference which approached statistical significance (P = 0.06). This study shows that fluconazole is by far less toxic than amphotericin B and suggests that it might be as effective as amphotericin B, in pragmatical terms and for this specific indication. However, numbers are too small to allow definitive conclusions about efficacy, and the use of fluconazole for this indication remains experimental. Future studies should try to identify patients more at risk of fungal infections, with the aim of individualising antifungal approaches.

Adolescent↗
PubMed1996

Impaired interleukin-3 mRNA decay in autocrine mast cell tumors after transient calcium ionophore stimulation.

Autocrine interleukin-3 (IL-3) expression of v-H-ras transformed mast cell tumors involves either IL-3 mRNA stabilization (class-I tumors) or enhanced IL-3 transcription (class-II tumors). Since calcium ionophores induce IL-3 expression in untransformed PB-3c cells by transcript stabilization, we asked whether class-I tumor could still respond to calcium ionophores. We found that ionomycin treatment further increased IL-3 mRNA expression of class-I tumor cells. Following ionomycin wash-out, IL-3 mRNA decay was slower in class-I tumor cells than in class-II tumor or precursor cell lines (t1/2 > 50 min versus < 20 min, respectively). Somatic cell fusion of the class-I tumor cells with the non-tumorigenic PB-3c cells resulted in reversion to rapid decay after ionomycin wash-out. The data indicate that a recessive defect of IL-3 mRNA degradation can be revealed in class-I tumor cells by transient calcium ionophore stimulation. However, IL-3 mRNA stabilization operating constitutively in class-I tumor cells appears to be distinct from the ionomycin induced process.

Animals↗
PubMed1996

99mTc-sestamibi and 201-Thallium at rest: dual scintigraphic mapping of myocardial injury in infarcted patients.

UNLABELLED: 201-Thallium (Tl) and (99m)Tc-sestamibi (SM) present different biological properties and kinetics, suggesting a complementary evaluation of mitochondrial and cell membrane functions with subsequent implications regarding myocardial injury mapping. To verify the usefulness of a dual isotopic approach in Q infarcted patients, 30 subjects were submitted at rest, within 5 days, to SM imaging, 4h-delayed Tl scans and echocardiography (ECHO). Left ventricle segmental uptake and wall motion were graded on a 3 points scale (0=absent to 2=normal) and compared on the basis of an 11 segments model. RESULTS AND DISCUSSION: 1) The analysis of SM normal segments demonstrated a strong concordance (97%) with Tl and ECHO, suggesting that both mitochondrial and cell membrane functions are preserved; 2) 49% of SM graded 0 segments were scored 1 by Tl and ECHO, suggesting a worse impairment of mitochondrial function with respect to cell membrane function; 3) approximately 55% of segments showing a reduced MIBI uptake were found normal using Tl, then an impaired mitochondrial but a normal cell membrane function could be hypothesized. 4) Tl provided a better estimation of the effective infarction size with respect to SM. CONCLUSIONS: The SM and Tl dual approach, allowing scintigraphic mapping of myocardial injury, seems to provide a useful tool for a complete evaluation of infarcted patients.

Echocardiography↗
PubMed1995

Interleukin-3 mRNA stabilization by a trans-acting mechanism in autocrine tumors lacking interleukin-3 gene rearrangements.

Tumors obtained from v-Ha-ras-transformed PB-3c cells are characterized by autocrine interleukin-3 (IL3) expression, which occurs either without (class I tumors) or with enhanced transcription (class II tumors). To address possible post-transcriptional mechanisms of IL3 expression, IL3 mRNA stability was examined in both tumor classes. Increased stability of IL3 mRNA was detected in class I tumor lines (t1/2 > 3 h), whereas rapid decay of IL3 transcripts (t1/2 < 0.5 h) was found in class II tumor lines. In both tumor classes, the c-myc and interleukin-6 transcripts were short-lived. Transcripts of a constitutively expressed IL3 reporter gene were stable in class I tumor cells but unstable in class II tumor cells, suggesting that IL3 mRNA stabilization involved a trans-acting mechanism. Rapid decay of IL3 reporter transcripts was observed in untransformed PB-3c as well as in v-Ha-ras expressing precursor cells linking transcript stabilization to the tumor stage. Reporter transcript stabilization in class I tumor cells correlated with increased IL3 production. Deletion of the AU-rich element from the IL3 reporter gene further augmented IL3 mRNA levels as well as IL3 production, suggesting that the stabilizing mechanism in class I tumor cells is not equivalent to AU-rich element deletion.

Animals↗
PubMed1995

AUH, a gene encoding an AU-specific RNA binding protein with intrinsic enoyl-CoA hydratase activity.

AU-rich elements within the 3' untranslated region of transcripts of lymphokines and some protooncogenes serve as signal for rapid mRNA degradation. By using an AUUUA matrix, we have affinity-purified a 32-kDa protein, microsequenced it, and cloned the corresponding cDNA. In vitro, the recombinant protein bound specifically to AU-rich transcripts, including those for interleukin 3, granulocyte/macrophage colony-stimulating factor, c-fos, and c-myc. Sequence analysis revealed an unexpected homology to enoyl-CoA hydratase (EC 4.2.1.17), and the recombinant protein showed a low degree of the enzymatic activity. Thus, this gene, designated AUH, encodes an RNA binding protein with intrinsic enzymatic activity. Protein immobilized on an AUUUA matrix was enzymatically active, suggesting that hydratase and AU-binding functions are located on distinct domains within a single polypeptide.

Amino Acid Sequence↗
PubMed1995

Changing pattern of pathogens causing broviac catheter-related bacteraemias in children with cancer.

The incidence of pathogens causing catheter-related bacteraemias in children undergoing antineoplastic chemotherapy with or without bone marrow transplantation at G. Gaslini Children's Hospital, Genoa, Italy, was analysed by comparing data from a retrospective study (1985-1988) with that obtained from a prospective one (1989-1992). In both periods catheter-related bacteraemias one (1989-1992). In both periods catheter-related bacteraemias were more frequent in non-neutropenic than in neutropenic patients. Among catheter-unrelated bacteraemias the pattern of infecting pathogens remained unchanged between the study periods, with Gram-positive bacteria remaining the predominant pathogens. Conversely, among catheter-related bacteraemias, the incidence of Gram-negative bacilli increased significantly from 3 to 38%, and that of Gram-positive bacteria fell from 63 to 32% (P = 0.001, chi 2 test for heterogeneity.

Antineoplastic Agents↗
PubMed1995

Sestamibi imaging and echocardiography: a combined approach to myocardial infarction.

The resting relationship of MIBI segmental uptake to regional wall motion has been studied in 30 patients with postinfarction wall motion abnormalities. The purpose of this study was to verify whether an integrated approach using Sestamibi (MIBI) imaging (perfusion analysis) combined with echocardiography (ECHO) (wall motion analysis) could present an additive value to differentiate infarcted from viable myocardial areas with respect to MIBI imaging alone. The same 11 segments model for left ventricle was used to compare segmental wall motion scores versus segmental uptake scores using a chi 2 analysis. The global score frequency rates for MIBI and ECHO were examined and a subsequent comparative analysis score versus score on each segment was performed. Our data, based on a chi 2 analysis, indicated that MIBI imaging overestimates the effective area of necrosis, underestimating, furthermore, hypoperfused but non-necrotic myocardium. We can conclude that an integrated approach based on both segmental perfusion and wall motion analysis, seems to be clinically suitable for a correct evaluation of infarcted patients, especially in view of revascularization procedures, providing an additive value in discriminative capacity, with respect to MIBI scintigraphic analysis alone.

Echocardiography↗
PubMed1994

Functional hierarchy of AUUUA motifs in mediating rapid interleukin-3 mRNA decay.

In mast cells, expression of interleukin-3 (IL-3) is induced following IgE-receptor activation via calcium-dependent mRNA stabilization. We performed a mutational analysis of the 8 AUUUA motifs located in the 3'-untranslated region of IL-3 mRNA, and analyzed the effect on mRNA stability in PB-3c mast cells. Similar to endogenous IL-3 mRNA, exogenous IL-3 transcripts had a short half-life and were stabilized following stimulation of calcium influx by ionomycin. Specific mutation of 3 AUUUA motifs had almost the same stabilizing effect as deletion of the entire AU-rich region. Mutating even a single critical motif led to a weak, but significant mRNA stabilization. Ionomycin treatment did not further enhance the expression of mutationally stabilized transcripts. Our data fit a model, where within a cluster of 6 AUUUA motifs, 3 adjacent motifs are required for binding of a factor which mediates rapid IL-3 mRNA decay. Activity of such a factor might be under control of a calcium-dependent pathway.

Animals↗
PubMed1994

Cyclosporin A inhibits growth of autocrine tumour cell lines by destabilizing interleukin-3 mRNA.

In T cells, cyclosporin A (CsA) exerts its immunosuppressive effect by preventing transcriptional induction of the expression of interleukin(IL)-2. This is achieved by a mechanism that involves binding of a CsA-cyclophilin complex to calcineurin, which in turn inhibits the phosphatase-controlled translocation of transcription factor NFAT to the nucleus. We have previously identified IL-3 as an autocrine oncogenic regulator in tumour cell lines generated by introducing the v-H-ras oncogene into IL-3-dependent mast cells. Here we report that CsA specifically blocks autocrine tumour cell growth. The mechanism involves down-regulation of IL-3 expression by destabilization of the messenger RNA and requires ongoing transcription. Transcripts from exogenous IL-3 genes lacking the (A+U)-rich element (ARE) in the 3' untranslated terminal repeat could not be destabilized, suggesting that at least part of this sequence, which is known to mediate decay of short-lived mRNA, participates in a CsA-sensitive regulatory mechanism.

Animals↗
PubMed1994

Comparison of polymerase chain reaction with standard methods in the diagnosis of Mycobacterium tuberculosis infection.

The polymerase chain reaction (PCR) method was evaluated in the detection of Mycobacterium tuberculosis in comparison with direct microscopy and culture procedures including the standard radiometric system (Bactec). Amplified DNA fragments from clinical samples were analyzed by dot-blot and non-radioactive oligonucleotide hybridization techniques or by agarose gel electrophoresis. The results revealed nested PCR to be the method of choice. The combination of three culture methods could detect Mycobacterium tuberculosis in only 79% of PCR-positive cases. The mean time required to achieve a positive culture result was 17 days in contrast to the PCR method requiring only two to three days. The nested PCR assay provided rapid and reliable results allowing a definitive diagnosis particularly in a number of samples which were negative on culture.

Bacteriological Techniques↗
PubMed1994

Modulation of cytokine expression in PB-3c mastocytes by IBMX and PMA.

Stimulation of mast cells, either via the IgE receptor or with calcium ionophore triggers the production of several cytokines, such as interleukins-3, -4, -5, and -6, and GM-CSF. In PB-3c mastocytes, ionophore-induced IL-3 and GM-CSF expression is primarily the result of mRNA stabilization, and is enhanced by oncogenic ras. Apart from mobilizing calcium, the IgE receptor activation leads to production of DAG and elevation of cAMP levels, thereby activating protein kinases C and A, respectively. The influence of these two secondary messengers on cytokine production was examined using the cAMP elevating agent IBMX, the phorbol ester PMA, and the staurosporine derivative CGP 41251, which preferentially inactivates PKC. IBMX was determined to be a potent coinducer of IL-3 expression, whereas elevation of IL-6 and GM-CSF was more pronounced in PMA-treated cells. Both PMA and IBMX were shown to act posttranscriptionally on IL-3, by extending the half-life of the mRNA. Ionophore-induced cytokine expression appears to require serine/threonine kinase activity, as it could be abolished by treatment with the drug CGP 41251. Our results therefore suggest that the factors regulating cytokine expression and mRNA stability are subject to regulation by serine/threonine phosphorylation.

1-Methyl-3-isobutylxanthine↗
PubMed1993

Suppressible and nonsuppressible autocrine mast cell tumors are distinguished by insertion of an endogenous retroviral element (IAP) into the interleukin 3 gene.

After v-H-ras expression, the interleukin 3 (IL-3)-dependent PB-3c mast cells progress in vivo to two different classes of IL-3 autocrine tumors. Class I tumors show a germline configuration of the IL-3 gene and represent more than 90% of tumors analyzed so far. Somatic cell fusion of class I tumor lines with the nontumorigenic parental PB-3c resulted in loss of oncogenic IL-3 expression by a posttranscriptional mechanism with concomitant tumor suppression. Class II tumors arise rarely and contain an insertion in one IL-3 allele. This alteration was linked to enhanced IL-3 gene transcription. For one tumor, the insertion was shown to be an endogenous retroviral element (intracisternal A-particle). Cell hybrids of class II tumors with PB-3c remained IL-3 independent, expressed IL-3, and formed tumors rapidly. These results suggest that the v-H-ras oncogene synergizes with a recessive and a dominant lesion in class I and II tumors, respectively, both of which lead to the autocrine production of IL-3.

Animals↗
PubMed1992

Mast cells sensitive to v-H-ras transformation are hyperinducible for interleukin 3 expression and have lost tumor-suppressor activity.

Subcloning of interleukin 3 (IL-3)-dependent PB-3c mastocyte cells revealed two populations, of which only one is sensitive to oncogenic transformation by v-H-ras. The corresponding tumors produce IL-3 and grow in vitro in the absence of exogenous IL-3 [Nair, A.P.K., Diamantis, I.D., Conscience, J.F., Kindler, V., Hofer, P. & Moroni, Ch. (1989). Mol. Cell. Biol., 9, 1183-1190]. In the present investigation, IL-3 gene regulation was compared in ras transformable (rT) and ras nontransformable (rNT) lines. We report that upon expression of v-H-ras rT clones but not rNT clones express low levels of IL-3 mRNA as detected by reverse polymerase chain reaction. Treatment with ionomycin, a calcium ionophore, induced high levels of IL-3 expression only in ras-expressing rT clones. Somatic cell fusion between the rNT clone 20 and the IL-3-expressing mastocytoma line V2D1 led to down-regulation of IL-3 expression and to the requirement for exogenous IL-3 for in vitro growth and tumor suppression. In contrast, rT clone 15 lacked tumor-suppressor activity and failed to down-regulate IL-3 expression in somatic hybrids which grew in vitro without added IL-3. Our results indicate that IL-3 gene expression is a critical determinant for the generation of v-H-ras-induced mast cell tumors and show that disturbances in IL-3 gene regulation can be detected already at the premalignant level in v-H-ras transformation-sensitive cells.

Animals↗