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Biomedical subjects

F Ventura

Publications and source records attributed to F Ventura.

At least 19 recordsLinked to original sources
PubMed1999

A zinc-finger transcription factor induced by TGF-beta promotes apoptotic cell death in epithelial Mv1Lu cells.

Transforming growth factor-beta (TGF-beta) superfamily members constitute a group of multifunctional factors that are able to stimulate apoptotic cell death in a variety of cells. In this report, we show that a zinc-finger transcription factor (TIEG) is an immediate early gene transcriptionally induced by TGF-beta in the epithelial Mv1Lu cell line. We also demonstrate that, mimicking TGF-beta effects, ectopic overexpression of TIEG is sufficient to trigger the apoptotic cell program in these cells, which is preceded by a decrease of Bcl-2 protein levels. Finally, apoptotic events elicited by TIEG overexpression can be effectively prevented by ectopic co-expression of Bcl-2. On the basis of these results we suggest that induction of TIEG expression has a role in the pro-apoptotic properties of TGF-beta.

Animals↗
PubMed1999

Development of a solid-phase microextraction GC-NPD procedure for the determination of free volatile amines in wastewater and sewage-polluted waters.

An analytical procedure for the determination of free volatile C1-C6 amines in aqueous matrixes has been developed and applied to their determination in waste-water, primary and secondary effluents, and sewage-polluted river samples. The developed analytical procedure involves headspace sampling using solid-phase microextraction with a poly(dimethylpolysiloxane) coating (100 microns) followed by GC-NPD determination and GC/MS confirmation using a tailor-made PoraPLOT amines capillary GC column for volatile amines. Procedural detection limits were compound dependent but ranged from 3 to 56 micrograms L-1, being close to or lower than the odor threshold concentration, and the reproducibility was ca. 15% (N = 5) in real water samples. The developed analytical procedure is solvent free, cost-effective (no cryogenic trap needed), and faster than existing methods because no derivatization step is involved in the determination. Linearity was compound dependent but ranged at least from 50 to 600 micrograms L-1.

Amines↗
PubMed1999

Solid-phase microextraction for the determination of iodinated trihalomethanes in drinking water.

A headspace solid-phase microextraction (HS-SPME) method has been developed for the determination of iodinated trihalomethanes (ITHMs) in treated water samples. Mixed THMs (bromochloroido-, bromodiiodo-, chlorodiiodo-, dibromoiodo- and dichloroiodo-) were previously synthesized since commercial standards are not available. HS-SPME has shorter equilibration times than direct SPME, a cleaner background and a longer fiber life. Experimental parameters such as the selection of SPME coatings, sample volume, extraction time and addition of salts were studied. The Carbowax-divinylbenzene fiber appears to be the most suitable for the determination of ITHMs. Analytical parameters such as linearity, limit of detection and precision were also evaluated. HS-SPME was compared to liquid-liquid microextraction for the analyses of spiked treated water samples, obtaining a good agreement. It is concluded that HS-SPME has a great potential for drinking water analysis.

Adsorption↗
PubMed1999

Bone morphogenetic protein-2 promotes dissociated effects on the number and differentiation of cultured ventral mesencephalic dopaminergic neurons.

Bone morphogenetic proteins (BMPs) are a family of growth differentiation factors which induce bone formation from mesenchymal cells. These proteins are members of the transforming growth factor-beta super-family. The expression of BMPs in the nervous system as well as in other tissues has been reported. In this study, we show that the presence of BMP-2 resulted in a dose-dependent increase in the number of tyrosine hydroxylase-immunoreactive ventral mesencephalic cells after 7 days in serum-free medium cultures. A maximal response was elicited at 10 ng/mL. BMP-2 also increased the number of primary neurites and branch points as well as the length of the longest neurite in a dose-dependent manner, with a maximal effect at 1 ng/mL. In contrast, BMP-2 did not modify the number or the function of GABAergic neurons. On the other hand, we observed stimulation of proliferation and morphological changes in glial cells (astrocytes become more fibrous shaped) in the presence of a high BMP-2 concentration (100 ng/mL), but not with lower doses, suggesting that the neurotrophic effect in dopaminergic neurons is not mediated by astroglial cells. This is consistent with the fact that the BMP-2 effect on dopaminergic neurons was observed even when the cultures were treated with alpha-aminoadipic acid to exclude the presence of glial cells. In summary, our data indicate that BMP-2 is a potent neurotrophic factor for ventral mesencephalic dopaminergic cells in culture.

Animals↗
PubMed1998

JunB is involved in the inhibition of myogenic differentiation by bone morphogenetic protein-2.

Bone morphogenetic proteins (BMPs) constitute a family of multifunctional growth and differentiation factors structurally related to transforming growth factor-beta. BMPs were first identified by their osteoinductive effects, inducing ectopic bone formation when implanted in skeletal muscle, and have an important role as regulators of skeletal development in vivo. In vitro, BMP-2 is able to transdifferentiate myogenic C2C12 cells into the osteoblastic phenotype. In this report, we show that the osteoinductive effects of BMP-2 in C2C12 cells are mediated by bone morphogenetic protein receptor type-IA in combination with both activin receptor type II and bone morphogenetic protein receptor type II. We also analyzed the expression levels of nuclear protooncogenes to understand early transcriptional events induced by BMP-2. We show that junB is an immediate early gene induced by BMP-2 and transforming growth factor-beta. BMP-2 induces transcriptional activation of JunB expression as early as 30 min after ligand addition, reaching maximal levels after 90 min. Increase of JunB mRNA correlates with a higher AP-1 binding activity. Furthermore, ectopic overexpression of JunB is sufficient to inhibit expression of myoblast differentiation markers in C2C12 cells. These data, taken together, show the involvement of JunB in the early steps of inhibition of myogenic differentiation induced by transforming growth factor-beta family members.

Bone Morphogenetic Protein 2↗
PubMed1998

[Is the use of ribavirin aerosols in respiratory syncytial virus infections justified? Clinical and economic evaluation].

UNLABELLED: The controversy about the use of ribavirin aerosol for children at risk (cardiopathy, pneumopathy, premature and immunodeficient patients), in case of respiratory syncytial virus (RSV) infection, led us to stop its prescription in 1993 and study prospectively the patients admitted during the following winters. METHODS: Criterias of inclusion for this study were those of the Committee on Infectious Diseases of the American Academy of Pediatrics concerning the use of ribavirin aerosol. Two cohorts of patients were studied: the first group included treated patients (ribavirin group: n = 22, ribavirin and support treatment: salbutamol aerosols, respiratory physiotherapy and oxygen-therapy; winters 1989-1990 to 1992-1993); the second group included patients with support treatment only (control group: n = 22; winters 1993-1994 and 1994-1995). RESULTS: The clinical gravity score at admission (4.55 vs 5.23, P = 0.46) and the risk factor scores (3.05 vs 3.27, P = 0.69) of the two groups were identical. Results showed that the children of the ribavirin group stayed much longer in hospital (14.2 vs 8.2 days, P = 0.002) and in the intensive care unit (7.2 vs 0.2 days, P < 0.001) than those of the control group. More support treatment was necessary for the ribavirin group as regard respiratory physiotherapy (3.8 vs 2.7 sessions a day, P = 0.026), the duration of oxygen-therapy (7.3 vs 3.7 days, P = 0.030) and the number of children requiring respiratory assistance (4 vs 0 children, P = 0.116). Administration of ribavirin aerosols (480 US$ a dose) and the way in which such treatment was carried out meant high daily costs for the ribavirin group (1,076 vs 604 US$, P < 0.001). As hospitalization was longer for children treated with ribavirin, the global cost was therefore much higher (15,552 vs 5,156 US$, P < 0.001). CONCLUSION: The antiviral effect of ribavirin is undeniable. However ribavirin is known to be the cause of severe bronchospasms (two cases in our study) and can also cause moderate and long term bronchospasms, aggravating therefore the clinical evolution of the disease. Our experience shows that administration of ribavirin aerosols in case of RSV infection of inferior respiratory airways seems not to be justified.

Aerosols↗
PubMed1998

Intracranial insertion of a nasogastric tube in a case of homicidal head trauma.

A case of accidental intracranial penetration of a 29-cm-long portion of nasogastric tube (NGT) in a 27-year-old female victim of a severe homicidal skull and brain trauma is reported. Accidental penetration of the NGT occurred through a large fracture of the ethmoid lamina cribrosa. In addition to a systematic review of previously reported cases, circumstantial data, clinical aspects, and autopsy data have been analyzed to draw medicolegal considerations concerning the connection between death and insertion of an NGT, which may also contribute to the ascertaining of any possible professional responsibility of medical staff, in a case fraught with numerous legal complications.

Adult↗
PubMed1998

Molecular cloning, expression, and chromosomal localization of a ubiquitously expressed human 6-phosphofructo-2-kinase/ fructose-2, 6-bisphosphatase gene (PFKFB3).

We report the identification of a human 6-phosphofructo-2-kinase/fructose 2,6-bisphosphatase gene (PFKFB3) isolated from a human fetal brain cDNA library. The gene was localized to 10p15-->p14 by fluorescence in situ hybridization. The entire cDNA (4,322 bp) codes for a polypeptide of 520 amino acid residues (molecular weight, 59.571 kDa). Structural analysis showed the presence of a kinase domain located at the amino terminus and a bisphosphatase domain at the carboxy terminus, characteristic of previously described 6-phosphofructo-2-kinase/fructose 2, 6-bisphosphatase isozymes. In addition, a phosphorylation site for cAMP-dependent protein kinase was found at the carboxy terminus. Northern blot analysis showed the presence of a unique 4.8-kb mRNA expressed in the different tissues studied. In mammalian COS-1 cells, this cDNA drives the expression of an active isozyme. Taken together, these results identify the presence of a gene coding for a human 6-phosphofructo-2-kinase/fructose 2,6-bisphosphatase isozyme which is ubiquitously expressed.

Animals↗
PubMed1997

Polychlorinated naphthalenes in groundwater samples from the Llobregat aquifer (Spain).

Polychlorinated naphthalenes (PCNs) have characteristics fairly similar to those of polychlorinated biphenyls and terphenyls (PCBs and PCTs) and although they have been used in numerous applications, very few reports on the occurrence of PCNs in water have been published. Both automated solid-phase extraction (SPE) and liquid-liquid extraction (LLE) procedures were evaluated to concentrate PCNs. High-resolution gas chromatography with electron-capture detection (HRGC-ECD) and mass spectrometric detection in the selected ion monitoring mode (SIM) were used to analyze PCNs in groundwater samples from the aquifer of the Llobregat river near Barcelona (NE Spain). The homologue distribution profiles of PCNs found in groundwater samples and the standard mixtures of Halowax (1099, 1013 and 1014) were compared. Quantification was achieved by HRGC-ECD. Total PCN concentrations expressed as Halowax 1099 equivalents ranged from < 0.5 ng/l to 79.1 micrograms/l in the water samples, with tetrachloronaphthalenes (TetraPCN) as the major group of congeners.

Gas Chromatography-Mass Spectrometry↗
PubMed1997

Assessment of polychlorinated naphthalenes in aquifer samples for drinking water purposes.

Polychlorinated naphthalenes (PCNs) were identified and quantified in water samples collected from the aquifer of the Llobregat river near Barcelona (NE Spain) in order to establish the source and extent of spreading of the contamination. Many of the identified PCNs were well resolved as single peaks on the chromatograms recorded using high resolution gas chromatography combined with electron ionization high resolution mass spectrometry and single-ion monitoring. The profile and pattern of PCNs found in groundwater samples are similar to those of Halowax 1099. The levels of the sum of mono- to octachloronaphthalenes in the water samples ranged from 0.003 microgram/L to 72.9 micrograms/L.

Gas Chromatography-Mass Spectrometry↗
PubMed1997

Cell-mediated immune responses to mycobacterial antigens in patients with pulmonary tuberculosis and HIV infection.

Lymphocyte proliferation and cytokine responses induced by a panel of mycobacterial antigens were compared in Portuguese donors with pulmonary tuberculosis (TB) with or without HIV co-infection, HIV+ patients and healthy Mantoux-positive controls. Control donors showed stronger proliferative responses than any of the patient groups, with secreted antigens (Mycobacterium tuberculosis (Mtb) 30 kD and short-term culture filtrate proteins (ST-CFP)), purified protein derivative (PPD) and Mtb H37Rv Sonicate (MtbS) inducing the strongest proliferation. Patients with pulmonary TB showed lower proliferation to PPD or to the 30-kD antigen. Responses to all the antigens (PPD, ST-CFP, MtbS, 70 kD, 65 kD, 38 kD, 30 kD and 10 kD) were higher in TB/HIV patients with CD4 counts > or = 200 CD4+ T cells/mm3 compared with HIV alone (CD4 > or = 200 T cells/mm3), but were lost in both TB/HIV and HIV patients when CD4 counts fell below 200 T cells/mm3. Measurements of interferon-gamma (IFN-gamma) in culture supernatants revealed that PPD, 30 kD, MtbS and ST-CFP induced the strongest Th1 response. Analysis of mRNA for IFN-gamma, IL-4 and IL-10 confirmed that IFN-gamma production was maintained in patients with pulmonary TB without any concomitant increase in IL-4 or IL-10 mRNA expression, although expression of IL-10 mRNA was increased if HIV infection was present. These results reveal that IFN-gamma production is retained in pulmonary TB patients to a broad range of mycobacterial antigens, and that no switch to IL-4 production is seen even with HIV infection. Secreted antigens, and in particular ST-CFP, were the best inducers of IFN-gamma secretion, confirming their role in protective responses to Mtb.

Adult↗
PubMed1996

Interaction of transforming growth factor-beta receptor I with farnesyl-protein transferase-alpha in yeast and mammalian cells.

Transforming growth factor beta (TGF-beta) signals through two transmembrane serine/threonine kinases, known as TbetaR-I and TbetaR-II. Several lines of evidence suggest that TbetaR-II acts as a primary receptor, binding TGF-beta and phosphorylating TbetaR-I whose kinase activity then propagates the signal to unknown substrates. We report an interaction between TbetaR-I and the farnesyl-protein transferase-alpha subunit (FT-alpha) both in a yeast two-hybrid system and in mammalian cells. These findings raise the possibility that TGF-beta might regulate cellular functions by altering the ability of FT-alpha to catalyze isoprenylation of targets such as G proteins, lamins, or cytoskeletal components. However, we provide evidence that TGF-beta action does not alter the overall protein isoprenyl transferase activity in Mv1Lu mink lung epithelial cells. In fact, the beta subunits of farnesyl transferase and geranylgeranyl transferase, which are necessary for the activity of FT-alpha, prevent the association of FT-alpha with TbetaR-I. Furthermore, farnesyl transferase activity is shown to be dispensable for TGF-beta signaling of growth inhibitory and transcriptional responses in these cells. These results suggest that the interaction between TbetaR-I and FT-alpha does not affect the known functions of these two proteins.

Activin Receptors, Type I↗
PubMed1995

Role of the N-terminal region in covalent modification of 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase: comparison of phosphorylation and ADP-ribosylation.

The effect of cyclic AMP (cAMP)-dependent phosphorylation and ADP-ribosylation on the activities of the rat liver bifunctional enzyme, 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase (PFK-2/FBPase-2), was investigated in order to determine the role of the N-terminus in covalent modification of the enzyme. The bifunctional enzyme was demonstrated to be a substrate in vitro for arginine-specific ADP-ribosyltransferase: 2 mol of ADP-ribose was incorporated per mol of subunit. The Km values for NAD+ and PFK-2/FBPase-2 were 14 microM and 0.4 microM respectively. A synthetic peptide (Val-Leu-Gln-Arg-Arg-Arg-Gly-Ser-Ser-Ile-Pro-Gln) corresponding to the site phosphorylated by cAMP-dependent protein kinase was ADP-ribosylated on all three arginine residues. Analysis of ADP-ribosylation of analogue peptides containing only two arginine residues, with the third replaced by alanine, revealed that ADP-ribosylation occurred predominantly on the two most C-terminal arginine residues. Sequencing of the ADP-ribosylated native enzyme also demonstrated that the preferred sites were at Arg-29 and Arg-30, which are just N-terminal to Ser-32, whose phosphorylation is catalysed by cAMP-dependent protein kinase (PKA). ADP-ribosylation was independent of the phosphorylation state of the enzyme. Furthermore, ADP-ribosylation of the enzyme decreased its recognition by liver-specific anti-bifunctional-enzyme antibodies directed to its unique N-terminal region. ADP-ribosylation of PFK-2/FBPase-2 blocked its phosphorylation by PKA, and decreased its PFK-2 activity, but did not alter FBPase-2 activity. In contrast, cAMP-dependent phosphorylation inhibited the kinase and activated the bisphosphatase. These results demonstrate that ADP-ribosylation of arginine residues just N-terminal to the site phosphorylated by PKA modulate PFK-2 activity by an electrostatic and/or steric mechanism which does not involved uncoupling of N- and C-terminal interactions as seen with cAMP-dependent phosphorylation.

Adenosine Diphosphate Ribose↗
PubMed1995

Cloning and expression of a catalytic core bovine brain 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase.

A cDNA encoding the catalytic core of a novel brain 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase isoenzyme was isolated from a lambda gt10 bovine brain library. This brain cDNA begins and ends in an open reading frame encoding a peptide of 476 amino acids. This peptide contains both the catalytic kinase and bisphosphatase domains and has an overall 65% and 67% indentity with the bovine heart and liver isozymes, respectively, whereas the NH2 and COOH-termini are divergent. An active catalytic core brain bifunctional enzyme was expressed in E. coli using a T7 RNA polymerase-based expression system. These results support the presence of a distinct gene coding for the protein in bovine brain.

Amino Acid Sequence↗
PubMed1995

Effect of low-dose oral triphasic contraceptives on blood viscosity, coagulation and lipid metabolism.

The purpose of the study was to determine the relationship between hemorheological profile, i.e. blood viscosity, and other risk factors for cardiovascular and thrombotic diseases in women taking oral contraceptives and if blood viscosity may be considered a marker of cardiovascular risk in OC users. Plasma levels of coagulation parameters, serum lipids, blood viscosity and RBC deformability were determined in a group of 10 women taking OC vs. 10 controls. The blood parameters were evaluated before OC use and thereafter at 3 and 6 months. A significant change in the partial thromboplastin time, fibrinogen, HDL and apolipoprotein A-I was observed, while the other parameters remained unchanged. Plasma viscosity was significantly increased during OC treatment; whole blood viscosity and RBC deformability remained unchanged. However, although some parameters were significantly modified during OC treatment, all alterations remained within the normal range of laboratory values. The data confirm that low-dose triphasic OC therapy does not affect significantly the coagulation system, serum lipid metabolism and blood viscosity. Plasma viscosity measurement may be considered as a marker for monitoring women using OC because it is apparently the most sensitive parameter.

Adolescent↗
PubMed1995

Assessment of biological activity and fate of organic compounds in a reactor for the measurement of biodegradable organic carbon in water.

A new, rapid method for the determination of biodegradable dissolved organic carbon (BDOC), especially suited to water industry needs, was recently proposed by the authors. This dynamic method measured the BDOC of circulating water continuously pumped over a biofilm attached to a special support (sinterized porous glass) that fills a system of two glass columns. The BDOC value corresponds to the difference in dissolved organic carbon (DOC) between inflow and outflow water samples. The analytical results are not significantly different from those of other bioassays that use indigenous bacteria, and the total duration of the analysis is less than 3 h. However, a problem common to all the BDOC methods based on attached bacteria is the extent to which the decrease in DOC during the BDOC analysis is due to true biodegradation or to adsorption of organic matter to the reactor. In the present study, a reasonable support is provided for the hypothesis that this decrease, at least in the dynamic method, is predominantly due to microbiological activity. After comparing the support (sinterized porous glass) with a good physical adsorbent (granular activated carbon), the influence of temperature, residual chlorine and sodium azide on the reactor performance was tested, and a sensitivity only attributable to biological activity was observed. Another set of experiments were performed to assess the fate and specific elimination of different organic substances, explicable assuming that biodegradation processes were involved.

Azides↗