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P Rodriguez

Publications and source records attributed to P Rodriguez.

At least 37 records · Page 2Linked to original sources
PubMed1997

Functional characterization of human nucleosome assembly protein-2 (NAP1L4) suggests a role as a histone chaperone.

Histones are thought to play a key role in regulating gene expression at the level of DNA packaging. Recent evidence suggests that transcriptional activation requires competition of transcription factors with histones for binding to regulatory regions and that there may be several mechanisms by which this is achieved. We have characterized a human nucleosome assembly protein, NAP-2, previously identified by positional cloning at 11p15.5, a region implicated in several disease processes including Wilms tumor (WT) etiology. The deduced amino acid sequence of NAP-2 indicates that it encodes a protein with a potential nuclear localization motif and two clusters of highly acidic residues. Functional analysis of recombinant NAP-2 protein purified from Escherichia coli demonstrates that this protein can interact with both core and linker histones. We demonstrate that recombinant NAP-2 can transfer histones onto naked DNA templates. Deletion mutagenesis of NAP-2 demonstrates that both NH3- and COOH-terminal domains are required for histone transfer activity. Subcellular localization studies of NAP-2 indicate that it can shuttle between the cytoplasm and the nucleus, suggesting a role as a histone chaperone. Given the potential role of the human NAP-2 gene (HGMW-approved symbol NAP1L4) in WT etiology, we have elucidated the exon/intron structure of this gene and have analyzed the mutational status of NAP-2 in sporadic WTs. Our results, coupled with tumor suppression assays in G401 WT cells, do not support a role for NAP-2 in the etiology of WT. A putative role for NAP-2 in regulating cellular differentiation is discussed.

Amino Acid Sequence↗
PubMed1997

Clinical and angiographic implications of coronary stenting in thrombus-containing lesions.

OBJECTIVES: This study sought to determine the results of coronary stenting in thrombus-laden lesions. BACKGROUND: The angiographic evidence of intracoronary thrombus has classically been considered a formal contraindication to stent implantation. However, with increasing use of stenting, the indications for this technique have widened to include treatment of patients who have an acute coronary syndrome or lesions with adverse anatomic features. METHODS: We studied 86 consecutive patients (mean age +/- SD 61 +/- 11 years, 14 women) undergoing coronary stenting of a thrombus-containing lesion; the procedure was performed electively in 39% and after angioplasty failure in 61%. Sixty-four patients (75%) were treated for unstable angina, and 19 (22%) underwent the procedure during an acute myocardial infarction. A specific protocol that included clinical and late angiographic follow-up was used. RESULTS: Angiographic success was obtained in 83 patients (96%). Five patients (6%) died during the hospital stay despite angiographic success; four of these had cardiogenic shock, and one (1%) had subacute stent thrombosis. Non-Q wave myocardial infarction developed in five additional patients (6%), and four of these five had data consistent with distal embolization. Of the 78 patients discharged with angiographic success, 67 (86%) were event-free and clinically improved at last follow-up visit (12 +/- 11 months). During the follow-up period, eight patients required repeat angioplasty, one patient required heart transplantation, and two patients died. Quantitative angiography demonstrated excellent angiographic results after stenting (minimal lumen diameter 0.31 +/- 0.4 vs. 2.77 +/- 0.6 mm). Late angiographic follow-up (5.5 +/- 1 months) was obtained in 50 patients with 54 lesions (93% of eligible), revealing a minimal lumen diameter of 2.0 +/- 1 mm and restenosis (lumen narrowing > 50%) in 18 lesions (33%). CONCLUSIONS: Coronary stenting constitutes an effective therapeutic strategy for patients with thrombus-containing lesions, either after failure of initial angioplasty or electively as the primary procedure. Coronary stenting in this adverse anatomic setting results in a high degree of angiographic success, a low incidence of subacute thrombosis and an acceptable restenosis rate.

Adult↗
PubMed1997

Feasibility of intravascular ultrasound studies: predictors of imaging success before coronary interventions.

BACKGROUND: Intravascular ultrasound (IVUS) is currently used to study lesions during transcatheter coronary therapy. However, before dilation some lesions cannot be reached or crossed with the imaging catheter. HYPOTHESIS: This study seeks to elucidate which factors determine the feasibility of IVUS examination before coronary interventions. METHODS: Accordingly, 100 consecutive patients undergoing IVUS examination before coronary angioplasty were prospectively studied. The clinical and angiographic characteristics of 77 patients with a successful IVUS study (Group A) were compared with those of 23 patients in whom IVUS was attempted but the target lesion could not be interrogated (Group B). The echogenic characteristics of the target lesion [before (n = 77) or after intervention (in 18 patients in Group B)] were also studied. RESULTS: Patients in Group B were significantly older (62 +/- 7 vs. 57 +/- 10 years, p < 0.05) and more frequently had stable angina [8 (35%) vs. 9 (11%), p < 0.05]. The distribution of lesions within the coronary tree and angiographic lesion characteristics including length, eccentricity, calcification, bend location, and the American College of Cardiology/American Heart Association classification were similar in both groups. However, proximal tortuosities (> 45 degrees at end diastole) were more frequently found in Group B [20 (87%) vs. 47 (61%), p < 0.05]. In addition, by quantitative angiography, patients in Group B had smaller arteries (reference diameter 2.8 +/- 0.4 vs. 3.1 +/- 0.4 mm, p < 0.05) and more severe lesions (minimal lumen diameter 0.46 +/- 0.24 vs. 0.65 +/- 0.34 mm, p < 0.05). On IVUS, calcified lesions were more frequently visualized in Group B (61 vs. 38%, p < 0.05). On multivariate analysis, catheter size, baseline minimal lumen diameter, angiographic proximal tortuosities, and lesion calcification on imaging were independent predictors of the feasibility of IVUS studies. CONCLUSIONS: Unsuccessful IVUS studies before intervention occur more frequently (1) in vessels with proximal tortuosities or severe lumen narrowing, (2) in lesions that are calcified on IVUS, and (3) when large imaging catheters are used.

Angina Pectoris↗
PubMed1996

ATP-regulated activity of the plasmin-streptokinase complex: a novel mechanism involving phosphorylation of streptokinase.

Streptokinase, an extracellular protein produced by Streptococci, is capable of activating the human fibrinolytic zymogen plasminogen. The rate of amidolytic activity of the plasminogen-streptokinase complex is greatly diminished by micromolar concentrations of ATP and heparin oligosaccharides. In addition, the plasminogen activator activity of the plasminogen-streptokinase complex is also inhibited by these effectors. ATP and heparin oligosaccharides show structural similarity, suggesting that the inhibition is caused by binding of these molecules to a common newly formed binding pocket in streptokinase, which appears after interaction with plasminogen. Addition of the bivalent cations Ca2+ and Mg2+ reverses the inhibition caused by ATP and heparin. In the presence of ATP and bivalent cations, the complex between plasminogen and streptokinase develops an autophosphorylating activity whose target is the sequence LTSRPAHG in the 4.5 kDa streptokinase N-terminal peptide, which is an early autolysis peptide. This streptokinase N-terminal peptide, which is essential for streptokinase activating activity, may serve, once phosphorylated, in mechanisms related to the pathogenicity of Streptococci. These studies suggest a critical role for plasminogen in regulating the activity of the streptokinase molecule.

Adenosine Triphosphate↗
PubMed1996

A Tn1545-like transposon carries the tet(M) gene in tetracycline resistant strains of Bacteroides ureolyticus as well as Ureaplasma urealyticum but not Neisseria gonorrhoeae.

The presence of the tet(M) determinant and conjugative transposons related to Tn1545 in urogenital pathogens, Bacteroides ureolyticus (10 strains), Neisseria gonorrhoeae (37 strains) and Ureaplasma urealyticum (81 strains), was studied by PCR analysis and hybridization assay. All tetracycline-resistant strains that hybridized with a probe specific for tet(M) gave the expected fragment when their DNA's were subject to PCR. The tet(M) gene and int-Tn, the gene encoding the protein required for the movement of Tn1545-like transposons, were always found together in tetracycline resistant strains of B. ureolyticus and U. urealyticum. In contrast, int-Tn was not detected in tet(M)-mediated tetracycline-resistant N. gonorrhoeae strains. These data suggest carriage of tet(M) by a Tn1545-like transposon in some tetracycline-resistant B. ureolyticus.

Bacteroides↗
PubMed1996

Intestinal paracellular permeability during malnutrition in guinea pigs: effect of high dietary zinc.

BACKGROUND: Zinc has been shown to have beneficial effects in vitro on epithelial barrier function, and in vivo to reduce intestinal permeability in malnourished children with diarrhoea. AIMS: To determine whether malnutrition alters intestinal paracellular permeability, and whether zinc prevents such alterations. METHODS: Guinea pigs were fed a normal protein diet (NP group), a low protein diet (LP group), or a low protein diet enriched with 1800 ppm zinc (LPZn group) for three weeks. Intestinal permeability was measured on jejunal segments mounted in Ussing chambers by measuring ionic conductance and mucosal to serosal fluxes of 14C-mannitol, 22Na, and horseradish peroxidase. Tight junction morphology was assessed on cryofracture replicas. RESULTS: Mannitol and Na fluxes and ionic conductance increased in the LP group compared with the NP group but remained normal in the LPZn group. Accordingly, jejunal epithelia from the LP group, but not from the LPZn group, showed a small decrease in number of tight junctional strands compared with epithelia from the NP group. Neither malnutrition nor zinc treatment modified horseradish peroxidase fluxes. CONCLUSIONS: Malnutrition is associated with increased intestinal paracellular permeability to small molecules, and pharmacological doses of zinc prevent such functional abnormality.

Animals↗
PubMed1996

Establishment of hepatic cell polarity in the rat hepatoma-human fibroblast hybrid WIF-B9. A biphasic phenomenon going from a simple epithelial polarized phenotype to an hepatic polarized one.

By immunofluorescence and freeze fracture methods, we have studied the establishment of hepatic cell polarity in WIF-B9 cells, a subclone of the WIF-B rat hepatoma-derived hybrid cell line. As previously shown (Ihrke et al. (1993) J. Cell Biol. 123, 1761-1775; Shanks et al. (1994) J. Cell Sci. 107, 813-825), these cells are a suitable model for in vitro studies of various hepatic functions, particularly polarity: in confluent cultures, the majority of cells form bile canaliculus-like structures; membrane domains are settled, according to plasma membrane protein localization similar to rat hepatocytes in situ. We here report that the establishment of WIF-B9 cell polarity is a slow progressive biphasic phenomenon. During the first days of culture, the majority of cells do not make bile canaliculus-like structures. However, they display a polarity similar to that of simple epithelial cells: apical membrane proteins and villin are found at the cell apex; basolateral ones, excluded from this area, are expressed in the remaining membrane area; the tight junction-associated protein ZO-1 and actin are concentrated at the boundary of these two poles, whereas E-cadherin is present at the lateral pole just under the apex. With time in culture, the number of cells expressing this simple epithelial polarized phenotype decreases progressively and, after 10-15 days, depending on the plating density, nearly all the cells express the typical hepatic polarized phenotype. The expression of these two phenotypes is mutually exclusive. Freeze-fracture replicas of both types of polarized cells show either macula occludens, fascia occludens (simple epithelial polarity) or zonula occludens (hepatic polarity), associated with gap junctions. In this last case, two or three continuous strands are generally present all around the bile canaliculus-like structures.

Actins↗
PubMed1996

[Molecular typing by pulsed field gel electrophoresis of Stenotrophomonas maltophilia isolated in a department of hematology].

Stenotrophomonas maltophilia is an important nosocomial pathogen. The increased isolates of S. maltophilia among hematology unit patients led to an epidemiological survey. Over 26 months, 24 strains isolated from 23 patients and an environmental isolate from blood pressure armband have been identified. The isolated were first analysed by the use of phenotypical markers: biotype, antibiotic susceptibility, but the minor differences observed justified a genotypic analysis. Pulsed field gel electrophoresis of genomic DNA was carried with XbaI and DraI restriction endonucleases by contour-clamped homogeneous electric field method (CHEF). The data obtained showed a great genomic diversity within the species S. maltophilia. Nevertheless, the same restriction profile was found for 3 patients and 3 other profiles were obtained for 3 couples of patients hospitalized at the same time. All the other strains isolated from subjects hospitalized during the same period exhibited pulsotypes independent from each other. Compared to biotypes and antibiotic susceptibility, these results indicate field only with non modified primers, and the absence of 460 mutations was confirmed by sequencing. Two isolates P1 and P2, from a transplanted patient were amplified with both primers MCMM and MCMW: sequencing analysis shown the presence of a mixture of strains, one of them harbouring A- > G 1378 mutation. One resistant strain was amplified neither with MCMM nor with MCMW: a C- > T silent mutation at nt 1368 was present. As sequencing analysis confirmed PCR results, discriminative PCR enables isolates to be rapidly assessed for the presence or absence of 460 mutations. Moreover, it can distinguish Met to Val from Met to Ile mutations, and allows the analysis of mixtures of sensitive and resistant strains.

Anti-Bacterial Agents↗
PubMed1995

Tumour necrosis factor-alpha induces morphological and functional alterations of intestinal HT29 cl.19A cell monolayers.

TNF-alpha is a widely distributed proinflammatory cytokine, involved in many disease states. Although it has widely distributed effects, a precise mechanism of action has never been described, in particular at the epithelial level. Morpho-functional changes of the intestinal epithelial monolayer HT29 cl.19A exposed to TNF-alpha were therefore assessed, using electron microscopy (including freeze-fracture replica analysis), as well as measurement of mannitol, Na+ and horseradish peroxidase fluxes across intestinal HT29 cl.19A cell monolayers using Ussing chambers. TNF-alpha receptors were induced on HT29 cl.19A cells by a small non-toxic dose of IFN-gamma (5 U/ml). After 4 h of the combined presence of TNF-alpha (10 ng/ml) and IFN-gamma (5 U/ml), the tight junction structure was altered as shown by a significant decrease in the average strand number measured in the apico-basal direction (5.50 +/- 2.70 vs 3.73 +/- 1.39 in control and treated cells respectively, P < 0.0001) and by a significant decrease in junctional depth (0.27 +/- 0.14 and 0.17 +/- 0.10 microns in control and treated cells respectively, P < 0.0001). These results are in agreement with a decrease in number of 'kiss' sites between contiguous membranes of TNF-alpha treated cells observed in ultrathin sections.(ABSTRACT TRUNCATED AT 250 WORDS)

Cell Membrane Permeability↗
PubMed1995

Detection of Chlamydia trachomatis by ligase chain reaction compared with polymerase chain reaction and cell culture in urogenital specimens.

OBJECTIVE: The aim of this study was to evaluate the newly developed ligase chain reaction (LCR) assay for the detection of Chlamydia trachomatis in urogenital specimens using cell culture and Amplicor PCR for comparison. SUBJECTS: Two hundred and eighty patients attending hospital or urban STD clinics (high-risk population, 62 men and 84 women) and obstetric/gynaecology clinics (low-risk population, 134 women) in Bordeaux, France. METHODS: Specimens from men were tested with LCR on urethral swabs and urine, with Amplicor or urine, with cell culture on urethral swabs. Specimens from women were tested with LCR, Amplicor and cell culture on endocervical swabs and with LCR on urine. When the three methods generated different results, the LCR and Amplicor tests were repeated on the remaining samples. Samples with discordant LCR and Amplicor results and a negative culture were further analysed by major outer membrane protein gene omp1-PCR. RESULTS: After analysis of discrepant results, the overall prevalence was 7.5% (21/280) calculated on the basis of an expanded "gold standard" defined as culture positive or LCR plus Amplicor positive or omp1-PCR positive for discrepant results between LCR and Amplicor tests. Of the 21, 20 were detected by LCR, 17 by Amplicor and culture. The specificity of LCR and Amplicor was 99.6%. CONCLUSION: The LCR Chlamydia trachomatis test is a highly sensitive nonculture technique and a good alternative test for the detection of chlamydial infections.

Bacteriological Techniques↗