Biomedical subjects

M Reina

Publications and source records attributed to M Reina.

At least 19 recordsLinked to original sources

PubMed2006

Sediment phosphate composition in relation to emergent macrophytes in the Doñana Marshes (SW Spain).

We have studied the effect of the presence of emergent macrophytes on the sediment phosphate composition of a eutrophic shallow marsh on the NE margin of Doñana (SW Spain). Top sediment and water samples were collected from both the open-water and the vegetated sites at three areas covered by different plant species: Scirpus maritimus, Juncus subulatus and Phragmites australis. The concentration of organic matter was significantly higher in the top sediment of sites covered by vegetation than in their adjacent open-water sites at the three vegetation areas. The P-fractional composition showed that the sediment was dominated by the inorganic P-fractions in all cases, reaching the highest concentration in the Ca-bound P-fraction (281-372 microg g(-1) d.w.). The sum of all P-fractions was significantly higher in the top sediment of the sites covered by J. subulatus and S. maritimus than in their adjacent open-water sites, and so were the org-P fraction extracted by hot NaOH and the concentration of phytate within this fraction. Deposition of plant material on the top sediment of areas vegetated by J. subulatus and S. maritimus explains these differences. The P-fractional composition of the seeds from J. subulatus showed that they contained a large proportion of organic P-fractions, particularly of the fraction extracted by hot NaOH (1868 microg g(-1) d.w., 85% of which was phytate). The presence of emergent macrophytes, therefore, influenced the distribution of P-fractions in the sediment depending on plant species. The P-bioavailability of shallow aquatic systems must be fully understood if wetlands are to be protected from further eutrophication.

Geologic Sediments↗

PubMed2005

Prevention of external ventricular drain--related ventriculitis.

OBJECTIVE: The purpose of this study was to test if a reduction of external ventricular drains (EVD) related ventriculitis could be achieved by a strict protocol of care and if protocol violation was associated with a higher incidence of EVD-related ventriculitis. METHODS: A written protocol for EVD insertion, nursing and surveillance was implemented. A retrospective comparison of EVD-related ventriculitis incidence was performed between control (161 EVD in 131 patients) and study periods (216 EVD in 175 patients). Risk factor analysis was performed in patients in whom an EVD was inserted during the study period including the relationship between protocol compliance and ventriculitis. A score for the number of protocol violations (absence of hair clipping, absence of a tunnelled EVD, absence of shampooing, incorrect dressing change, inappropriate CSF bag or tap samplings and EVD manipulation) was established for each patient. RESULTS: Incidence of patient-related ventriculitis decreased from 12.2% (1999) down to 5.7% (p<0.05) as well as incidence of EVD-related ventriculitis (9.9% vs 4.6%, p<0.05). During the study period, the only statistically significant risk factors for infection were CSF leak and protocol violations. The mean protocol violation score was 4 times higher in the infected versus the non-infected patients (p<0.0001). Patients with a violation score of 0 or 1 had no infection (EVD duration 2 to 42 days). CONCLUSION: EVD can be left safely, as long as needed, provided that meticulous care is taken for EVD insertion and nursing. EVD duration seems to have no effect on infection incidence.

Adult↗

PubMed2004

Anaesthesia for carotid endarterectomy: comparison of hypnotic- and opioid-based techniques.

BACKGROUND: Although the synergistic interaction between hypnotics and opioids for total i.v. anaesthesia has been repeatedly demonstrated, questions about different dose combinations of hypnotics and opioids remain. The optimal combination would be based on maximal synergy, using the lowest dose of both drugs and having the lowest incidence of side-effects. METHODS: The major goal of this prospective randomized study was to compare two different dose combinations of propofol and remifentanil (both administered by target controlled infusion (TCI)) in respect of haemodynamics during surgery and recovery, and the need for cardiovascular treatment in the recovery room. A secondary goal was to compare pain scores (VAS) and morphine consumption in the recovery room. Anaesthesia was induced in both groups using TCI propofol, adjusted to obtain a bispectral index score (BIS) value between 40 and 60. TCI for remifentanil commenced at an initial effect-site concentration of 0.5 ng ml(-1), and was adjusted according to haemodynamics. Patients were divided into one of two groups during anaesthesia: (i). Group H, hypnotic anaesthesia (n=23), propofol effect-site concentration maintained at 2.4 microg x ml(-1); and (ii). Group O, opioid anaesthesia (n=23), propofol effect-site concentration maintained at 1.2 microg x ml(-1). In both groups, remifentanil effect-site concentration was adjusted according to haemodynamics and changes in BIS value. RESULTS: In Group O, more episodes of intraoperative hypotension (P<0.02) and hypertension (P<0.01), and fewer episodes of tachycardia were observed. More patients in Group O required nicardipine administration for postoperative hypertension (8 patients in Group H vs 15 patients in Group O, P<0.04). During recovery, morphine titration was necessary in approximately 50% of patients. No significant difference between groups was observed concerning pain scores or requirement for morphine titration. CONCLUSIONS: Maintenance of anaesthesia predominantly with propofol and a low dose of remifentanil, both administered using TCI, is associated with greater stability in perioperative haemodynamics than anaesthesia predominantly with remifentanil alone. Postoperative pain was identical in both groups of patients who underwent relatively short duration, and relatively painless surgery.

Aged↗

PubMed2003

Different basic fibroblast growth factor and fibroblast growth factor-antisense expression in eutopic endometrial stromal cells derived from women with and without endometriosis.

In all species studied, the basic fibroblast growth factor (bFGF) gene is transcribed into multiple mRNAs, one of which is an antisense RNA (1B FGF-AS) probably involved in regulating the stability of the sense transcript. In this study we investigated whether the regulatory mechanisms of bFGF expression might be altered in endometrial stromal cells derived from women with endometriosis. bFGF and 1B FGF-AS mRNA levels were quantified in primary cultures of eutopic endometrial stromal cells derived from 29 women without endometriosis and 24 patients affected by the disease. When the data were analyzed according to the phase of the menstrual cycle, endometrial stromal cells derived from patients in the late proliferative phase showed significantly higher bFGF mRNA values and significantly lower 1B FGF-AS mRNA levels compared with control samples. Furthermore, the mean bFGF/1B FGF-AS mRNA ratio was significantly higher in endometrial stromal cells derived from patients compared with that in controls (mean +/- SEM, 2.31 +/- 0,55 and 0.77 +/- 0.14, respectively; P = 0.009). Moreover, for bFGF expression the differences existing at the mRNA level were maintained at the protein level. These findings support the hypothesis that 1B FGF-AS mRNA could regulate the expression of the sense transcript and suggest that in endometrial cells derived from patients, the presence of higher bFGF levels could improve their ability to proliferate at the ectopic site.

Base Sequence↗

PubMed2001

Syndecan-2 expression in colorectal cancer-derived HT-29 M6 epithelial cells induces a migratory phenotype.

Members of the heparan sulfate proteoglycan family, the syndecans have emerged as integrators of extracellular signals, such as ECM components or growth factors, that activate cytoplasmic signaling cascades and regulate cytoskeletal functions. Specifically, syndecan-2 has been implicated in various cellular processes, from differentiation to migration, including its participation in cell-cell and cell-matrix adhesion. Here, we focused on the involvement of syndecan-2 in epithelial versus mesenchymal differentiation. Colorectal cancer-derived HT-29 M6 epithelial cells were stably transfected with full-length syndecan-2 cDNA, and the effect on cell morphology, adhesion, and mobility was evaluated. Characteristic features of migratory cells such as loss of intercellular contacts, flatter shape and multiple membrane projections were observed in syndecan-2 transfectants. Western blot analysis of the major component of epithelial adherens junctions, E-cadherin, revealed decreased expression levels. Furthermore, syndecan-2 induced stronger adhesion to collagen type I, specifically inhibited by heparin. This was correlated with an increased ability for migration, as demonstrated by wound healing experiments and transwell assays, without affecting their growth rate. These results indicate that syndecan-2 expression in mucus-secreting HT-29 M6 cells induces differentiation toward a migratory mesenchymal-like phenotype.

Adenocarcinoma↗

PubMed2001

Cloning and characterization of human syndecan-3.

Syndecans are cell-surface heparan sulfate proteoglycans, which perform a variety of functions in the cell. Most important, they are co-receptors for growth factors and mediate cell-cell and cell-matrix interactions. Four syndecans (syndecan 1-4) have been described in different species. The aim of this work was the cloning and characterization of human syndecan-3. The human syndecan-3 sequence has high homology to the rat and mouse sequences, with the exception of the 5'-region. Syndecan-3 mRNA is mostly expressed in the nervous system, the adrenal gland, and the spleen. When different cell lines were transiently transfected with full-length syndecan-3 cDNA, it was localized to the membrane and induced the formation of long filopodia-like structures, microspikes, and varicosities. Consequently, the actin cytoskeleton was re-organized, since actin staining was mostly found in the cellular extensions and at the cell periphery, co-localizing with the syndecan-3 staining. The development of the phenotype depended on the presence of sugar chains, as transfected glycosaminoglycan-deficient Chinese hamster ovary (CHO) 745 cells did not show these structural changes, nor did transfected CHO K1 cells in the presence of heparin. The similarity of the cloned DNA sequence with that of other mammalian species and the high expression in the nervous system led us to the assumption that human syndecan-3 could perform comparable functions to those described for syndecan-3 in rat and mouse. Additionally, transient transfection experiments suggest a role of human syndecan-3 in the organization of cell shape by affecting the actin cytoskeleton, possibly by transferring signals from the cell surface in a sugar-dependent mechanism.

Actins↗

PubMed2001

Triacylglycerol-rich lipoproteins interact with human vascular cells in a lipid-dependent fashion.

Plasma triacylglycerol-rich lipoproteins (TRL) are being considered as a key lipid fraction in the pathogenesis of atherosclerotic cardiovascular disease. Here we compared the influence of two monounsaturated oils [virgin olive oil (VOO) and high-oleic sunflower oil (HOSO)] on the capability of postprandial TRL to interact with two human vascular cell lines [umbilical vein endothelial (HUVEC) and aorta smooth muscle (HASMC) cells]. A fluorescent probe was used for labeling TRL and to determine receptor activity of HUVEC and HASMC. The values for total cell-associated, bound, and internalized TRL were higher in HUVEC, and TRL from VOO was the better ligand recognized but at lower affinity than TRL from HOSO. There was a competitive effect of very low density lipoproteins (VLDL) for the uptake of TRL by cells, which was found to be dependent on the origin/lipid composition of the ligands and cell-type specific. We also conclude that the VLDL receptor (VLDLr) may contribute significantly to the HASMC binding capacity for postprandial TRL mediated by lipoprotein lipase (LPL) or LPL-binding molecules. Our findings are compatible with a selective role of the clustered O-linked sugar domain of the VLDLr in the catabolism of TRL by human vascular cells.

Adult↗

PubMed2001

Defensive chemistry of Senecio miser.

Three eremophilanolides, 1alpha-acetoxy-8beta-methoxy-10betaH-eremophil-7(11)-en-8alpha,12-olide (1); 1alpha-angeloyloxy-6beta-hydroxy-8beta-methoxy-10betaH-eremophil-7(11)-en-8alpha,12-olide (2); and 1alpha-angeloyloxy-8betaH,10betaH-eremophil-7(11)-en-8alpha,12-olide (3), and two pyrrolizidine alkaloids, integerrimine (4) and its N-oxide (5), were isolated from bioactive fractions of Senecio miser. The structures of the new compounds 1 and 2 were established by NMR spectroscopic analysis and chemical transformation. The X-ray analysis of compound 1 was also performed. Eremophilanolides 1 and 2 and alkaloids 4 and 5 were found to be strong insect antifeedants, further supporting a proposed defensive role for these classes of compounds.

Animals↗

PubMed2001

Heliotropium huascoense resin exudate: chemical constituents and defensive properties.

From the resinous exudate of Heliotropium huascoense a new compound, rel-(8R,9R)-carrizaloic acid, (1) (3-[rel-(8R,9R-9-hydroxy-9,13,13-trimethyl-12-oxo-10-cyclohexenyl)methyl]-4-methoxybenzoic acid), and three known flavonoids, [3-methylgalangin, 3,7-dimethylgalangin, and (-)-alpinone] have been isolated. The structure of 1 was determined by spectral and chemical methods. Several plant defensive properties of 1 (insecticidal and antifungal) have been evaluated.

Animals↗

PubMed2001

RGD peptides and monoclonal antibodies, antagonists of alpha(v)-integrin, enter the cells by independent endocytic pathways.

Cyclic synthetic peptides containing the arginine-glycine-aspartate motif (cRGD) and monoclonal antibodies (mAbs) targeted for individual integrins have been developed as potential therapeutic drugs for the treatment of several diseases. We showed that a cRGD peptide targeted for alpha(v)beta(3) was internalized in alpha(v)-integrin expressing and nonexpressing melanoma cells by an integrin independent fluid-phase endocytosis pathway that does not alter the number of functional integrin receptors at the cell surface. In contrast, a blocking mAb directed to alpha(v) was internalized by an integrin-dependent endocytosis pathway that reduced the number of functional integrin receptors at the cell surface. We prove that melanoma cells pretreated with the mAb do not readhere to the substrate, whereas cells pretreated with cRGD peptide retain their readhesion capacity. Given the growing importance of RGD peptides, knowledge of these cellular mechanisms is required to improve the development of antiangiogenic and anti-inflammatory drugs.

Antibodies, Monoclonal↗

PubMed2000

Reproducibility of time-domain and three different frequency-domain techniques for the analysis of the signal-averaged electrocardiogram.

Because time-domain (TD) analysis of the signal-averaged ECG (SAECG) has some limitations that limit its use, several frequency-domain analysis techniques were developed in an attempt to improve the diagnostic ability of the SAECG. However, it is not known how reliable these techniques are at detecting late potentials. This prospective study compares the short-term reproducibility of 4 analysis techniques: TD analysis, spectral temporal mapping (STM), spectral turbulence analysis (STA), and acceleration spectrum analysis (ASA), in a large series of normal patients and post-myocardial infarction (MI) patients. Two consecutive SAECGs were recorded in 634 patients that were divided into 3 groups: 117 remote MI patients undergoing programmed electrical stimulation for the inducibility of ventricular tachycardia (Group 1), 407 consecutive acute MI survivors (Group 2), and in 110 healthy volunteers (Group 3). The diagnostic reproducibility of the 4 techniques was evaluated by comparing rates of inconsistent results (1 normal and the other abnormal). The numeric reproducibility for each technique was assessed by comparing the normalized differences of each single SAECG parameter between the 2 recordings. Inconsistent results of diagnostic reproducibility were observed in 4.1%, 6.9%, 9.8%, and 18.0%, with TD, STA, ASA, and STM, respectively. Comparisons of these rates were significantly different (P < .05) except between STA and ASA (P = .07). The numeric reproducibility was highest for TD parameters, lowest for STM factors of normality, and intermediate for STA and ASA indices. TD analysis remains the most reproducible SAECG analysis technique, whereas STM showed the worst reproducibility, which limits its clinical applicability. STA and ASA provide an acceptable intermediate reproducibility, the former being slightly, although not significantly, more reproducible than the latter.

Electrocardiography↗

PubMed2000

Alpha v integrin antagonists induce the disassembly of focal contacts in melanoma cells.

In recent years, several antagonists of alpha(v)beta3 have been used to develop therapeutic approaches to the treatment of melanoma neoplasia. We studied the effects of anti-alpha(v)-integrin-blocking antibodies on attached M21 melanoma cells, the cellular distribution of alpha(v)-integrin and the molecular organization of focal structures. Anti-alpha(v)-integrin-blocking antibodies 17E6 and LM609, and an anti-alpha(v)beta3-integrin antagonist peptide cRGD 85189 induced detachment of M21 melanoma cells cultured for 24 hours on various substrates. cRGD was the most effective antagonist, reducing the number of adherent cells by 80%, while 17E6 reduced adhesion by only 30%. Light- and electron microscopy revealed attached cells with a flat shape and well-formed actin cytoskeleton. After treatment, cells became rounded and detached from the culture dish. alpha(v)-Integrins and focal-contact proteins were observed at adhesion sites in focal structures by immunocytochemistry. After treatment, however, cell rounding was accompanied by disorganization of the actin filaments and redistribution of alpha(v)-integrins and most of the focal proteins studied, except vinculin and tensin. Our results indicate that treatment of M21 melanoma cells with a(v)-integrin antagonists disrupts the actin cytoskeleton, redistributes a(v)-integrin and induces molecular disassembly of focal contacts.

Actins↗

PubMed2000

[The use of collagen in the cicatrization of wounds].

The authors review the use of collagen in the cicatrization of wounds, analyzing what this process consists of and what its regeneration and reparation phases are. The authors also summarize some fundamental biological aspects collagen has, their functions in hemostasia and in cicatrization; they develop the use of heterologous collagen in the cicatrization process. Expressive illustrations and a selection of bibliographical references accompany this article.

Cicatrix↗

PubMed1999

The role of O-linked sugars in determining the very low density lipoprotein receptor stability or release from the cell.

The very low density lipoprotein receptor is a member of the low density lipoprotein receptor supergene family for which two isoforms have been reported, one lacking and the other containing an O-linked sugar domain. In order to gain insight into their functionality, transient and stable transformants separately overexpressing previously cloned bovine variants were analyzed. We report evidence that the variant lacking the O-linked sugar domain presented a rapid cleavage from the cell and that a large amino-terminal very low density lipoprotein receptor fragment was released into the culture medium. As only minor proteolysis was involved in the other very low density lipoprotein receptor variant, the clustered O-linked sugar domain may be responsible for blocking the access to the protease-sensitive site(s). To test this hypothesis, a mutant Chinese hamster ovary cell line, ldlD, with a reversible defect in the protein O-glycosylation, was used. The instability of the O-linked sugar-deficient very low density lipoprotein receptor on the cell surface was comparable to that induced by the proteolysis of the variant lacking the O-linked sugar domain. Moreover, our data suggest that the O-linked sugar domain may also protect the very low density lipoprotein receptor against unspecific proteolysis. Taken together, these results indicate that the presence of the O-linked sugar domain may be required for the stable expression of the very low density lipoprotein receptor on the cell surface and its absence may be required for release of the receptor to the extracellular space. The exclusive expression of the variant lacking the O-linked sugar domain in the bovine aortic endothelium opens new perspectives in the physiological significance of the very low density lipoprotein receptor.

Animals↗

PubMed1999

Syndecan-2 induces filopodia by active cdc42Hs.

The syndecans, a family of transmembrane heparan sulfate proteoglycans, are ubiquitous molecules whose intracellular function is still unknown. To examine the function of syndecan-2, one of the most abundant heparan sulfate proteoglycan in fibroblasts, we performed transfection studies in COS-1 and Swiss 3T3 cells. Endogenous syndecan-2 colocalized with F-actin in cortical structures. Overexpression of full-length syndecan-2 induced the formation of long filopodia-like structures. These changes correlated with a rearrangement of the actin cytoskeleton, which strongly colocalized with syndecan-2. Overexpression of syndecan-2 lacking the extracellular domain increased the number of microspikes on the cell surface but failed to induce filopodia. Addition of heparin blocked the effect of full-length syndecan-2, suggesting that heparan sulfate chains in the extracellular domain are necessary to induce filopodia. Coexpression of cdc42Hs negative-dominant N17 blocked syndecan-2-induced filopodia and cdc42Hs positive-dominant V12 had a synergic effect. This indicates that active cdc42Hs is necessary for syndecan-2 induction of filopodia. These results provide a link between syndecan-2, actin cytoskeleton, and cdc42Hs.

3T3 Cells↗

PubMed1999

Improved diagnostic value of combined time and frequency domain analysis of the signal-averaged electrocardiogram after myocardial infarction.

BACKGROUND: Time domain analysis (TD) of the signal-averaged electrocardiogram (SAECG) presents a higher incidence of false positives in inferior myocardial infarction (MI), whereas spectral turbulence analysis (STA) suffers from a higher incidence of false positives in anterior MI. We investigated the hypothesis that a combined TD and STA (TD+STA) analysis of the SAECG could improve its predictive accuracy for major arrhythmic events (MAE) after MI. METHODS: Signal-averaged electrocardiograms were prospectively recorded 10.1 +/- 2.6 days after acute MI in 602 patients. Time domain analysis and STA were performed using standard parameters and criteria for abnormality. For the combined TD+STA model, stepwise discriminant analysis was utilized to optimize prediction of MAE. Receiver operating characteristic curves were utilized to optimize cutoff values for each SAECG parameter separately, and also for the combined TD+STA model. RESULTS: During a one-year follow-up period, 38 patients had MAE: 14 sustained ventricular tachycardia, 2 resuscitated ventricular fibrillation and 22 sudden cardiac deaths. The total predictive accuracy of combined TD+STA (89.9%) was significantly higher than TD (75.1%) or STA (77.6%). The negative predictive accuracy of all three analyses was high (98%). The positive predictive accuracy of TD (19.6%) or STA (18.3%) was quite low, and significantly improved to 35.8% by combined TD+STA analysis. The positive predictive accuracy of TD+STA improved to 51.2% in patients with left ventricular ejection fraction <40%. CONCLUSIONS: Combined TD + STA analysis of the SAECG significantly improves its prognostic ability for MAE in post-MI patients compared with TD or STA analyzed separately.

Arrhythmias, Cardiac↗

PubMed1998

Antifeedant Delphinium Diterpenoid Alkaloids. Structure-Activity Relationships.

The insect antifeedant and toxic activity of the Delphinium diterpene alkaloids 15-acetylcardiopetamine, cardiopetamine along with its amino alcohol, the beta,gamma unsaturated ketone, and the acetylated ketone derivatives were studied in Spodoptera littoralis and Leptinotarsadecemlineata. Cardiopetamine and 15-acetylcardiopetamine strongly inhibited the feeding activity of S. littoralis and L. decemlineata, respectively. Structure-activity studies with S. littoralis showed that the C13 and C15 hydroxy substituents are essential features of the active molecule, while a C13 hydroxy and/or a C15 acetate determined their effect on L.decemlineata. The C11 benzoate group enhanced the biological effect on both insect species. These alkaloids were not toxic to S. littoralis, while their toxicity on L. decemlineata was inversely correlated with their antifeedant effects, the beta,gamma unsaturated ketone derivative being the most toxic. Cardiopetamine showed little antifungal action against several species of plant pathogens and did not have any mutagenic effects on Salmonella typhimurium by means of the Ames test.

Journal Article↗

PubMed1998

Pyrrolizidine alkaloids from Heliotropium megalanthum.

Two pyrrolizidine alkaloids, megalanthonine (1) and lycopsamine (2), have been isolated from Heliotropium megalanthum. The structure of the novel compound 1 was determined by spectroscopic methods. The insecticidal, antifeedant, and antifungal effects of compounds 1 and 2 have been evaluated.

Animals↗