Biomedical subjects

C Moroni

Publications and source records attributed to C Moroni.

At least 19 recordsLinked to original sources

PubMed2007

Continuous antibiotic infusion for salvage therapy of partially implanted central venous catheter tunnel infections due to staphylococci.

Tunnel infection is an uncommon but serious complication observed in patients with partially implanted central venous catheters. International guidelines suggest that should include antibiotics and catheter removal. A success rate of only 5-20% was reported without catheter removal. We treated 13 episodes of tunnel Gram-positive bacterial infection occurring in pediatric patients with cancer or serious blood disorders with 24-hr intra-catheter antibiotic continuous infusion. This approach led to a 69% success rate. Continuous infusion might be an attractive option to treat tunnel Gram-positive bacterial infections when catheter removal might not be feasible or advisable.

Adolescent↗

PubMed2006

Isolation and characterization of dominant and recessive IL-3-independent hematopoietic transformants.

Retroviral integration mutagenesis and treatment with the frameshift mutagen ICR191 were used to transform v-H-ras expressing PB-3c cells to interleukin-3 (IL-3) independence. Six clones displayed viral integrations into the 3' region of the IL-3 gene thus acting post-transcriptionally by disrupting the AU-rich instability element. Two clones contained reverse orientation integration into the raf-1 gene revealing an enhancer insertion mechanism. Growth by this mechanism was sensitive to the Raf-1 inhibitor BAY 43-9006 and the Mek inhibitor U0126. Following treatment with ICR191, IL-3-independent clones were recovered and studied by cell fusion. With 21/22 clones, IL-3 independence resulted from a recessive mechanism as cellular hybrids with parental cells reverted to IL-3 dependence. Recessive clone D2c displayed increased phospho-Erk1/2 levels and was growth sensitive to U0126, but not to BAY43-9006. The single dominant clone, D5a, showed no signs of mitogen-activated protein kinases pathway activation but displayed constitutive phosphorylation of Stat5. We conclude that PB-3c has several options to acquire IL-3 growth autonomy involving transcriptional or post-transcriptional mechanisms affecting the distal regulators Erk or Stat5. The reported panel of independent dominant and recessive transformants should provide a useful tool for inhibitor profiling.

Aminacrine↗

PubMed2006

Homocysteinylation of low-density lipoproteins (LDL) from subjects with Type 1 diabetes: effect on oxidative damage of human endothelial cells.

BACKGROUND: Homocysteine (Hcy) is an independent risk factor for cardiovascular disease (CVD). Individuals with Type 1 and Type 2 diabetes are more susceptible to the effects of homocysteine than non-diabetic subjects. The interaction between homocysteine-thiolactone (Hcy-thiolactone), a reactive product of Hcy, and low-density lipoproteins (LDL) induces the formation of homocystamide-LDL adducts (Hcy-LDL) and it has been suggested that homocysteinylation could increase atherogenicity of lipoproteins. AIM: The aim of the study was to compare the effect of in vitro homocysteinylation of LDL isolated from healthy control subjects (C-LDL) and from Type 1 diabetic patients (DM-LDL) and to investigate the effect of homocysteinylated LDL (Hcy-C-LDL and Hcy-DM-LDL) on peroxynitrite production of endothelial cells. METHODS: The in vitro homocysteinylation of LDL isolated from control (n = 12) and DM subjects (n = 12) was carried out by incubating lipoproteins with Hcy-thiolactone. The reaction was verified by quantifying the increase in sulphydryl groups (-SH groups) in Hcy-LDL with respect to control LDL. Control and homocysteinylated LDL were incubated with human aortic endothelial cells (HAEC) in culture. Peroxynitrite production in cells treated in different experimental conditions was assayed by a fluorimetric method. RESULTS: The increase in -SH groups after incubation with homocysteine was greater in LDL from diabetic subjects compared with LDL from control subjects (P < 0.001). In addition, peroxynitrite production from HAEC incubated with Hcy-LDL from diabetic patients was greater than after incubation with Hcy-LDL from control subjects and untreated LDL from diabetic patients (P < 0.001). CONCLUSIONS: These results show that LDL from diabetic patients is more susceptible to in vitro homocysteinylation than LDL from non-diabetic individuals and demonstrate that the compositional changes in Hcy-LDL from diabetic subjects have cytotoxic effects on human endothelial cells.

Adult↗

PubMed2005

Peroxynitrite production and NOS expression in astrocytes U373MG incubated with lipoproteins from Alzheimer patients.

Apolipoprotein E (apo E), a plasma protein involved both in the metabolism of cholesterol and triglycerides, particularly in nervous tissue, has been associated with a higher risk of Alzheimer's disease. It has been shown that apo E increased the production of nitric oxide (NO) from human monocyte-derived macrophages (MDM); this effect could represent an important link between tissue redox balance and inflammation, since inflammation and oxidative stress are involved in chronic neurodegenerative disorders. Moreover, it has been evidenced that an overproduction of NO in the central nervous system (CNS) may play a key role in aging and that the glial cells (microglials cells and probably astrocytes) are able to form consistent amounts of NO through the induction of a nitric oxide synthase (iNOS) isoform so-called inducible or inflammatory. This report was performed in order to elucidate the effects produced by lipoproteins from control subjects, AD patients and first degree relatives (offspring) on human astrocyte cells after a short incubation. Peroxynitrite and NO production and NOS expression in cultured astrocytes were measured. We observed a decreased NO production after incubation with both LDL and HDL and an increased peroxynitrite production. As it concerns NOS expression, densitometric analysis of bands indicated that iNOS protein levels were significantly higher in the cells incubated with both AD lipoproteins and offspring lipoproteins compared to cells incubated with control lipoproteins. These findings suggest the possibility to identify in NO pathway a precocious marker of AD.

Aged↗

PubMed2004

Paraoxonase activity in high-density lipoproteins: a comparison between healthy and obese females.

Paraoxonase, an enzyme associated with high-density lipoprotein (HDL-PON), exerts a protective effect against oxidative damage of circulating cells and lipoproteins, modulates the susceptibility of HDL to atherogenic modifications such as glycation and homocysteinylation, and even exerts an antiinflammatory role. The aim of the present study was to investigate the relationship between lipoprotein oxidative stress and the activity of HDL-PON in healthy and obese subjects. Therefore, the activity of HDL-PON and the levels of lipid hydroperoxides in HDL and low-density lipoprotein (LDL) isolated from plasma of obese females (n = 12) and age-sex-matched controls (n = 31) were compared. Our results demonstrated for the first time that the activity of HDL-PON in obese subjects was significantly lower compared with that in controls (P < 0.001). Moreover, our results showed a significant increase in the levels of lipid hydroperoxides in HDL and LDL isolated from obese subjects (P < 0.001). The negative correlations established between HDL-PON activity and the levels of lipid hydroperoxides associated with HDL and LDL confirm the relationship between paraoxonase activity and lipid peroxidation of lipoproteins. Plasma levels of leptin correlated negatively with HDL-PON activity and positively with levels of lipid hydroperoxides in HDL and LDL of obese subjects, suggesting a relationship between leptin and oxidative damage of lipoproteins. In conclusion, our study demonstrated that the increase in oxidative stress in LDL and HDL of obese subjects is associated with a decrease in HDL-PON activity. The lower paraoxonase activity and the compositional changes in HDL and LDL could contribute to the greater risk of cardiovascular disease associated with obesity.

Adult↗

PubMed2004

LDL and HDL affect nitric oxide metabolism in human astrocytoma cells.

Astrocytes provide structural, trophic and metabolic support to neurons and modulate synaptic activity. Under physiological conditions, neuronal-derived nitric oxide (NO) plays an important role in the modulation of a variety of central nervous system (CNS) functions. NO, although short lived, can travel sufficient distances to be able to act as an intercellular messenger in the brain. Its targets include adjacent neurons and astrocytes. The aim of the present study was performed in order to investigate the effects produced by incubation of lipoproteins, at different times, with human astrocytoma cells and thus measuring NO and its metabolite production. NO and peroxynitrite production, iNOS and nNOS expression by Western immunoblot were evaluated. The LDL and HDL-treated cells showed an increased production of NO, more evident after 12 h, compared to basal levels; concerning peroxynitrite production, LDL and HDL-treated cells showed a higher fluorescence, more evident at 3 h. nNOS and iNOS protein levels were significantly higher in the cells incubated with control LDL and HDL. The present work supports the hypothesis that lipoproteins can induce the formation of reactive astrocytes, inducing iNOS as reported by other authors, giving experimental support to a role played by LDL and HDL inducing a reactive response.

Aged↗

PubMed2004

Clinical callosum syndrome in a case of multiple sclerosis.

This case report confirms that a clinical callosal disconnection could be observed in multiple sclerosis. Moreover, this case describes a new kind of strange manual behavior related to callosal disconnection. This behavior could neither be considered as a diagonistic dyspraxia nor as an alien hand, but they evoke rather a conflict of intentions.

Adult↗

PubMed2001

AU binding proteins recruit the exosome to degrade ARE-containing mRNAs.

Inherently unstable mammalian mRNAs contain AU-rich elements (AREs) within their 3' untranslated regions. Although found 15 years ago, the mechanism by which AREs dictate rapid mRNA decay is not clear. In yeast, 3'-to-5' mRNA degradation is mediated by the exosome, a multisubunit particle. We have purified and characterized the human exosome by mass spectrometry and found its composition to be similar to its yeast counterpart. Using a cell-free RNA decay system, we demonstrate that the mammalian exosome is required for rapid degradation of ARE-containing RNAs but not for poly(A) shortening. The mammalian exosome does not recognize ARE-containing RNAs on its own. ARE recognition requires certain ARE binding proteins that can interact with the exosome and recruit it to unstable RNAs, thereby promoting their rapid degradation.

3' Untranslated Regions↗

PubMed2001

Global analysis of differential gene expression after transformation with the v-H-ras oncogene in a murine tumor model.

Mouse PB-3c mast cells stably transfected with the v-H-ras oncogene induce tumor formation in vivo when implanted into mice. Such tumor cells are characterized by an autocrine IL-3 loop. DNA microarrays allow simultaneous transcript imaging of several thousand genes and the technique was applied in this tumor model to analyse gene expression following malignant transformation. Using three independent tumor lines derived from the same precursor the expression of about 400 out of 11 000 genes was modulated in each tumor. A subset of only 75 genes (0.68%) is shared and up- or downregulated in all three lines. A significant portion of this gene pool possesses functions related to tumorigenesis such as cell adhesion, signaling or transcriptional regulation. Apart from a number of expressed sequence tags (EST's) we find downregulation of four interferon-inducible genes in the tumor lines. Finally, when we extrapolate our data to the complete mouse genome, we estimate that about 500 genes are differentially expressed in tumor cells compared to the precursor cell PB-3c.

Animals↗

PubMed2001

Surgical treatment and clinical outcome of GH-secreting adenomas in elderly patients.

Patients older than 65 years represent 3-5% of all acromegalic patients. The old age of the patients and the higher incidence of cardiovascular and metabolic complications related to acromegaly could increase the intra- and peri-operative risk, so that medical treatment is usually recommended as a therapy of choice. The aim of this retrospective study was to investigate the impact of transsphenoidal surgery in a series of 22 elderly patients with active acromegaly, with special regard to anaesthesiological risk, peri-operative complications, and clinical outcome. Despite an increased anesthesiological risk being present in 16/22 patients, no complication occurred during surgery. Similarly, no post-operative mortality or major complications were observed. Biochemical cure, defined at 6 months by glucose-suppressed plasma GH levels below 1 ng/ml and normal age-corrected IGF-I value levels, was achieved in 68% of patients and no recurrence of disease was observed in the subsequent follow-up (mean 5.2+/-2.1 years). A significant cardiovascular improvement was observed in cured patients, with a decrease of left ventricular mass index (91.3+/-20.1 vs 115.9+/-15.0 g/m(2); P<0.005), as measured by echocardiography, as well as a slight but significant decrease of systolic and diastolic blood pressure values (130.0+/-12.1 mmHg vs 137.6+/-13.5 mmHg P<0.05; and 84.2+/-6.4 mmHg vs 88.8+/-7.5 mmHg P<0.05, respectively). A significant post-operative improvement of glucose tolerance was also observed in this group. We conclude that transsphenoidal surgery, if well planned and carefully performed, is safe and able to induce a significant cardiovascular and metabolic improvement even in elderly acromegalic patients.

Acromegaly↗

PubMed2001

Relationship between blood pressure and glucose tolerance in acromegaly.

BACKGROUND: Hypertension represents a well-known risk factor for cardiovascular diseases. The pathogenesis of hypertension in acromegaly is commonly viewed as multifactorial, but the possible influence of metabolic disorders on blood pressure (BP) in affected patients is largely unknown. OBJECTIVE: The aim of the present study was to evaluate the impact of glucose metabolism abnormalities on BP values in a series of patients with active acromegaly. DESIGN: An open multicentre prospective study. PATIENTS: Sixty-eight patients with active disease, aged 47.5 +/- 11.7 years, have been studied. Thirty-nine had normal glucose tolerance (NGT), 16 impaired glucose tolerance (IGT) and 13 suffered from diabetes mellitus (DM). MEASUREMENTS: Mean clinical BP values were calculated as the mean of BP values obtained by sphygmomanometric measurement in three separate occasions and mean 24-h, diurnal and nocturnal systolic (SBP) and diastolic (DBP) values were obtained by 24-h ambulatory blood pressure monitoring (ABPM). RESULTS: Patient's age and the degree of glucose tolerance abnormalities were found to significantly and independently influence BP values. All clinical and ABPM SBP and DBP values significantly increased with age by linear regression (P < 0.02 for all BP values, 0.30 < or = R < or = 0.43), and the independent influence of this parameter on BP values was confirmed by mutivariate analysis. Similarly, the independent influence of glucose tolerance abnormalities on BP values was confirmed when introducing age as a covariable in a multivariate analysis, and patients with DM presented significantly higher clinical SBP and 24-h, diurnal and nocturnal SBP and DBP than patients with NGT (P < 0.02 for clinical SBP, P < 0.015 for all ABPM values, respectively). In addition, patients with DM showed significantly higher 24-h, diurnal and nocturnal DBP than those with IGT (P < 0.05 in all cases). In contrast, no significant difference was found between NGT and IGT patients. No significant influence of disease duration, BMI, GH, IGF-I, or fasting and 2-h post glucose load insulinaemia on BP values was observed. CONCLUSIONS: Abnormalities of glucose metabolism significantly contribute to increase systolic blood pressure and especially diastolic blood pressure in acromegalic patients. Careful control of blood pressure and of risk factors for developing systemic hypertension, with special reference to glucose tolerance, is mandatory to decrease cardiovascular morbidity and mortality in such patients.

Acromegaly↗

PubMed2001

Marked improvement in cardiovascular function after successful transsphenoidal surgery in acromegalic patients.

OBJECTIVE: Transsphenoidal surgery results in biochemical remission of acromegaly in 45-80% of patients; however, few studies have addressed the impact of transsphenoidal surgery on cardiovascular function in acromegalic patients. The aim of this prospective study was to investigate the effects of postoperative GH/IGF-I normalization on echocardiographic parameters and blood pressure (BP) in a series of patients with active acromegaly. DESIGN: An open prospective study. PATIENTS: Thirty newly diagnosed acromegalic patients undergoing transsphenoidal surgery. MEASUREMENTS: Doppler echocardiography and 24-h ambulatory blood pressure monitoring were performed before and 6 months after transsphenoidal surgery. RESULTS: Fifteen patients were considered to be well controlled postoperatively (group A), as defined by normal age-corrected IGF-I levels and glucose-suppressed GH levels less than 2 mU/l, the remaining 15 patients being considered as poorly controlled (group B). In group A, a postoperative decrease of left ventricular mass index was observed (104.4 +/- 6.6 vs. 127.1 +/- 7.7 g/m2; P < 0.001), associated with an improvement of some indices of diastolic function, such as an increase of the early/late transmitral peak flow velocity (P < 0.05) and a decrease of isovolumic relaxation time (P < 0.01). No significant change was observed in group B. A significant decrease of 24-h systolic BP was also observed in group A (P < 0.05) and five of six patients normalized their BP circadian rythm. In contrast, a nonsignificant increase in BP values, with a persistent blunted BP profile where present, was observed in group B. CONCLUSIONS: We conclude that successful transsphenoidal surgery is able to induce a significant improvement in some cardiac parameters and a slight reduction in systolic blood pressure in acromegalic patients.

Acromegaly↗

PubMed2001

Parallel and independent regulation of interleukin-3 mRNA turnover by phosphatidylinositol 3-kinase and p38 mitogen-activated protein kinase.

AU-rich elements (ARE) present in the 3' untranslated regions of many cytokines and immediate-early genes are responsible for targeting the transcripts for rapid decay. We present evidence from cotransfection experiments in NIH 3T3 cells that two signaling pathways, one involving phosphatidylinositol 3-kinase (PI3-K), and one involving the p38 mitogen-activated protein kinase (MAPK), lead to stabilization of interleukin-3 mRNA in parallel. Stabilization mediated by either of the two pathways was antagonized by tristetraprolin (TTP), an AU-binding protein known to promote constitutive decay of ARE-containing transcripts. Remarkably, the stabilizing AU-binding protein HuR, in collaboration with p38 MAPK but not with PI3-K, could overcome the destabilizing effect of TTP. These data argue that the stabilizing kinases PI3-K and p38 MAPK do not act through direct inactivation of TTP but via activating pathway-specific stabilizing AU-binding proteins. Our data suggest an integrated model of mRNA turnover control, where stabilizing (HuR) and destabilizing (TTP) AU-binding proteins compete and where the former are under the positive control of independent phosphokinase signaling pathways.

3T3 Cells↗

PubMed2001

Cellular mutants define a common mRNA degradation pathway targeting cytokine AU-rich elements.

To functionally classify AU-rich elements (AREs) from six different cytokine mRNAs, we made use of two previously described HT1080-derived cellular mutants (slowA, slowC) that lack a function required for the rapid degradation of interleukin-3 (IL-3) mRNA. Here we show that the defect is specific for ARE-containing mRNAs, whereas nonsense-mediated decay is intact. Degradation of beta-globin reporter transcripts mediated by the AREs of IL-3, GM-CSF, and TNFalpha, as well as by the structurally different and less potent AREs of IL-2 and IL-6, is impaired in both mutants. All these reporter transcripts are also sensitive to decay induced by ectopic expression of the RNA-binding protein tristetraprolin in the slowC background. Thus, we concluded that the mutants slowA and slowC define a common mRNA degradation pathway that targets cytokine AREs. In NIH3T3 cells, this decay pathway becomes incapacitated by upstream signaling from p38 MAP- or PI3-kinases, which independently stabilize cytokine ARE-containing transcripts. In contrast, c-fos ARE-directed mRNA degradation proceeds through a different pathway not affected by these kinases.

3' Untranslated Regions↗

PubMed2000

Failure to identify the target does not prevent the attentional blink effect.

The attentional blink has been attributed to capacity limitations at a central level of processing. We tested whether failure to identify the target would eliminate the blink. Two agnostic patients were presented with streams of letters, which they were able to identify, and streams of pictures, which they were unable to identify. The dual-task involved identification of a target and detection of a probe. With letters the duration of the blink was equivalent to that of the control subjects. A prolonged blink was observed in both patients for pictures irrespective of whether the target was identified. This result indicates that failure to identify the target does nevertheless mobilize attentional resources sufficiently to prevent detection of a second target stimulus.

Aged↗

PubMed2000

DcE2F, a functional plant E2F-like transcriptional activator from Daucus carota.

In animal cells the progression of the cell cycle through G(1)/S transition and S phase is under the control of the pRB/E2F regulatory pathway. The E2F transcription factors are key activators of genes coding for several regulatory proteins and for enzymes involved in nucleotide and DNA synthesis. In this report we have detected the presence of E2F-like DNA binding activities in carrot nuclear extracts, and we have isolated a carrot cDNA (DcE2F) encoding a plant E2F homologue. The DcE2F gene is expressed in proliferating cells and is induced during the G(1)/S transition of the cell cycle. Supershift experiments using anti-DcE2F antiserum have confirmed that the DcE2F protein is a component of the carrot E2F-like nuclear activities. DNA binding assays have demonstrated that the DcE2F protein can recognize a canonical E2F cis-element in association with a mammalian DP protein. Furthermore, transactivation assays have revealed that DcE2F is a functional transcription factor that can transactivate, together with a DP partner, an E2F-responsive reporter gene in both plant and mammalian cells.

Amino Acid Sequence↗

PubMed2000

Somatic mRNA turnover mutants implicate tristetraprolin in the interleukin-3 mRNA degradation pathway.

Control of mRNA stability is critical for expression of short-lived transcripts from cytokines and proto-oncogenes. Regulation involves an AU-rich element (ARE) in the 3' untranslated region (3'UTR) and cognate trans-acting factors thought to promote either degradation or stabilization of the mRNA. In this study we present a novel approach using somatic cell genetics designed to identify regulators of interleukin-3 (IL-3) mRNA turnover. Mutant cell lines were generated from diploid HT1080 cells transfected with a reporter construct containing green fluorescent protein (GFP) linked to the IL-3 3'UTR. GFP was expressed at low levels due to rapid decay of the mRNA. Following chemical mutagenesis and selection of GFP-overexpressing cells, we could isolate three mutant clones (slowA, slowB, and slowC) with a specific, trans-acting defect in IL-3 mRNA degradation, while the stability of IL-2 and tumor necrosis factor alpha reporter transcripts was not affected. Somatic cell fusion experiments revealed that the mutants are genetically recessive and form two complementation groups. Expression of the tristetraprolin gene in both groups led to reversion of the mutant phenotype, thereby linking this gene to the IL-3 mRNA degradation pathway. The genetic approach described here should allow identification of the defective functions by gene transfer and is also applicable to the study of other mRNA turnover pathways.

Animals↗

PubMed2000

Calcium-dependent and oncogenic IL-3 mRNA stabilization can be distinguished pharmacologically and by sequence requirements in the 3'UTR.

In interleukin-3 (IL-3)-dependent PB-3c mast cells, the normally short-lived IL-3 mRNA is stabilized upon calcium-ionophore treatment or following v-H-ras induced oncogenesis. We compared the underlying stabilization mechanisms by analysing the response to the post-transcriptionally acting drugs cyclosporin A (CsA), FK506 and SB202190. Stable IL-3 transcripts in the PB-3c-derived tumour cell line V2D1 decayed in response to CsA and FK506, but not in response to SB202190. Transcripts stabilized by elevating intracellular calcium levels in PB-3c cells were destabilized in response to all three drugs. In PB-3c cells, six AUUUA pentamers within the AU-rich element were sufficient to confer responsiveness to calcium-ionophore and CsA treatment. In V2D1 tumour cells, sensitivity to CsA required additional nucleotides flanking these pentamers. Our data suggest that IL-3 mRNA stabilization by either calcium-dependent or oncogenic pathways involves different intracellular mechanisms.

3' Untranslated Regions↗