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Biomedical subjects

D Fernandez

Publications and source records attributed to D Fernandez.

At least 19 recordsLinked to original sources
PubMed2006

Recommendations for use of everolimus after heart transplantation: results from a Latin-American Consensus Meeting.

Despite improvements during the last decades, heart transplantation remains associated with several medical complications, which limit clinical outcomes: acute rejection with hemodynamic compromise, cytomegalovirus (CMV) infections, allograft vasculopathy, chronic renal failure, and neoplasias. Everolimus, a proliferation signal inhibitor, represents a new option for adjunctive immunosuppressive therapy. Everolimus displays better efficacy in de novo heart transplant patients than azathioprine for prophylaxis of biopsy-proven acute rejection episodes of at least ISHLT grade 3A (P < .001), of allograft vasculopathy (P < .01), and of CMV infections (P < .01). These findings suggest that everolimus potentially play an important role as part of immunosuppressive therapy in heart transplant recipients. Heart transplant investigators from Latin America produced recommendations for everolimus use in daily practice based on available data and their own experience.

Consensus Statements as Topic↗
PubMed2005

Dehydroleucodine inhibits vascular smooth muscle cell proliferation in G2 phase.

Vascular smooth muscle cell (VSMC) proliferation plays an important role in the development of atherosclerosis and in the vascular changes seen in hypertension. Dehydroleucodine (DhL) is a sesquiterpene lactone that inhibits cell proliferation in plant cells. In this paper, we study the effect of DhL in the proliferation of VSMCs stimulated with 10% fetal bovine serum (FBS). Very low concentrations of DhL (2-6 microM) inhibited VSMC proliferation and induced cell accumulation in G2. DhL did not affect the dynamics of 3H-thymidine incorporation, and did not modify either the activity of DNA polymerase or the incorporation of deoxyribonucleotides in an in vitro assay. Moreover, DhL did not induce apoptosis in VSMCs. These results indicate that DhL, in very low concentration, induces a transient arrest of VSMCs in G2. Our data show that VSMCs are especially sensitive to DhL effect, suggesting that DhL could be potentially useful to prevent the vascular pathological changes seen in hypertension and other vascular diseases.

Animals↗
PubMed2004

Sex pheromone of Argyrotaenia pomililiana (Lepidoptera: Tortricidae), a leafroller pest of apples in Argentina.

Sex pheromone gland extracts of Argyrotaenia pomililiana Trematerra & Brown females contained seven 14-chain compounds, the Z and E isomers of 11-tetradecenyl acetate, 11-tetradecen-1-ol, and 11-tetradecenal, respectively, together with tetradecyl acetate. In field trapping tests, a 100:5 blend of Z11-14:Ac and Z11-14:Al was shown to be suitable for detection and monitoring of A. pomililiana. This species-specific lure will facilitate the use of mating disruption against codling moth, Cydia pomonella (L.), in Argentine fruit orchards.

Animals↗
PubMed2003

[Quality of life instruments for women with pelvic organ prolapse].

OBJECTIVES: Our goal was to develop quality of life questionnaires in French for women with pelvic organ prolapse. MATERIAL AND METHOD: From two questionnaires previously developed for prolapse and validated in English, the Pelvic Floor Distress Inventory and the Pelvic Floor Impact Questionnaire, we have developed two questionnaires in French, the Inventaire des Symptômes de Prolapsus (ISP) and the Questionnaire sur l'Impact du Prolapsus (QIP). The ISP assesses symptom distress in women with pelvic floor disorders and measures how much these symptoms bother women. The QIP assesses life and emotional impact. These questionnaires were constructed after a double translation, a double expertise and patient interviews. A complete cross-validation into French is currently unfeasible due to cost considerations. RESULTS: The ISP and QIP questionnaires assess urinary, colorectal-anal and vaginal symptoms in relation to pelvic floor disorders. Both questionnaires significantly correlated with urinary and colorectal-anal symptoms. The main advantage of these instruments is the use of scales, with separate simple score for each scale. CONCLUSION: Based on two previously validated English questionnaires, the PFDI and the PFIQ, we have developed the first quality-of-life instruments in French for women with pelvic organ prolapse, the ISP and the QIP.

Fecal Incontinence↗
PubMed2001

Population genetics and dynamics of the black truffle in a man-made truffle field.

The colonization dynamics of the black truffle in an artificial field were assessed through analyses of microsatellite and RAPD markers. The truffle field was composed of three tree species and mycelial inoculum of three different origins, and was monitored for the first three years of truffle production. We found very low levels of genetic diversity. Isolation by distance was detected only at the between-tree level. This could be interpreted as local colonization around each tree facilitated by the presence of the tree root system. At the larger spatial scale of the European range, the absence of isolation by distance corroborates the hypothesis of an impact of glaciation on genetic variation, followed by rapid postglaciation demographic expansion. In addition, genetic variation of harvested truffles was explained by neither inoculation origin, nor tree species. Our study questions the real impact of man-made inoculation of tree root systems with fungal mycelia.

Agriculture↗
PubMed2000

alpha-t-butyl- and alpha-i-propyl-ortho-hydroxybenzylamines: racemic synthesis/resolution and asymmetric synthesis.

Efficient routes to alpha-tert-butyl- and alpha-iso-propyl-ortho-hydroxybenzylamines 1a and 1b are described. Highly enantioenriched 1a and 1b were obtained by resolution of the methoxy derivatives 2 by recrystallization of the salts formed with mandelic acid followed by Lewis acid mediated demethylation. The chiral 1,3-amino alcohol 1a has also been obtained in an asymmetric synthesis with the key step a diastereoselective alkylation of the imine obtained by condensation of o-anisaldehyde with phenyl glycinol. The absolute stereochemistry of these 1,3-aminophenols was determined by CD spectroscopy of the salicylideneamines 12 and by an X-ray structure analysis of the salt formed between (R)-mandelic acid and (S)-alpha-tert-butyl-ortho-methoxybenzylamine ((S)-2a).

Journal Article↗
PubMed1998

Fot 1 insertions in the Fusarium oxysporum f. sp. albedinis genome provide diagnostic PCR targets for detection of the date palm pathogen.

Populations of Fusarium oxysporum f. sp. albedinis, the causal agent of Bayoud disease of date palm, are derivatives of a single clonal lineage and exhibit very similar Fot 1 hybridization patterns. In order to develop a sensitive diagnostic tool for F. oxysporum f. sp. albedinis detection, we isolated several DNA clones containing a copy of the transposable element Fot 1 from a genomic library of the date palm pathogen. Regions flanking the insertion sites were sequenced, and these sequences were used to design PCR primers that amplify the DNA regions at several Fot 1 insertion sites. When tested on a large sample of Fusarium isolates, including 286 F. oxysporum f. sp. albedinis isolates, 17 other special forms, nonpathogenic F. oxysporum isolates from palm grove soils, and 8 other Fusarium species, the primer pair TL3-FOA28 allowed amplification of a 400-bp fragment found only in F. oxysporum f. sp. albedinis. Sequence analysis showed that one of the Fot 1 copies was truncated, lacking 182 bp at its 3' terminus. The primer pair BI03-FOA1 amplified a 204-bp fragment which overlapped the Fot 1 truncated copy and its 3' site of insertion in the F. oxysporum f. sp. albedinis genome and identified 95% of the isolates. The primer pairs BIO3-FOA1 and TL3-FOA28 used in PCR assays thus provide a useful diagnostic tool for F. oxysporum f. sp. albedinis isolates.

Cloning, Molecular↗
PubMed1996

Intermolecular disulfide bonds stabilize VirB7 homodimers and VirB7/VirB9 heterodimers during biogenesis of the Agrobacterium tumefaciens T-complex transport apparatus.

The Agrobacterium tumefaciens VirB7 lipoprotein contributes to the stabilization of VirB proteins during biogenesis of the putative T-complex transport apparatus. Here, we report that stabilization of VirB7 itself is correlated with its ability to form disulfide cross-linked homodimers via a reactive Cys-24 residue. Three types of beta-mercaptoethanol-dissociable complexes were visualized with VirB7 and/or a VirB7::PhoA41 fusion protein: (i) a 9-kDa complex corresponding in size to a VirB7 homodimer, (ii) a 54-kDa complex corresponding in size to a VirB7/VirB7::PhoA41 mixed dimer, and (iii) a 102-kDa complex corresponding to a VirB7::PhoA41 homodimer. A VirB7C24S mutant protein was immunologically undetectable, whereas the corresponding VirB7C24S::PhoA41 derivative accumulated to detectable levels but failed to form dissociable homodimers or mixed dimers with wild-type VirB7. We further report that VirB7-dependent stabilization of VirB9 is correlated with the ability of these two proteins to dimerize via formation of a disulfide bridge between reactive Cys-24 and Cys-262 residues, respectively. Two types of dissociable complexes were visualized: (i) a 36-kDa complex corresponding in size to a VirB7/VirB9 heterodimer and (ii) an 84-kDa complex corresponding in size to a VirB7/VirB9::PhoA293 heterodimer. A VirB9C262S mutant protein was immunologically undetectable, whereas the corresponding VirB9C262S::PhoA293 derivative accumulated to detectable levels but failed to form dissociable heterodimers with wild-type VirB7. Taken together, these results support a model in which the formation of disulfide cross-linked VirB7 dimers represent critical early steps in the biogenesis of the T-complex transport apparatus.

Agrobacterium tumefaciens↗
PubMed1996

Methylation status of 5'-regulatory region of tumor necrosis factor alpha gene correlates with differentiation stages of monocytes.

The DNA methylation status of the 5'-regulatory region of human tumor necrosis factor-alpha (TNF-alpha) gene was examined using two human monocytic cell lines representing different differentiation stages: one cell line, THP-1, represents the most differentiated macrophage-like phenotypes and the other, HL-60, represents a least differentiated phenotype. Two restriction enzymes were used to detect methylated sites in the 5'-regulatory region of the TNF-alpha gene. The restriction enzyme Msp I, which recognizes both CCGG (unmethylated) and C(me)CGG (methylated) sequences, whereas Hpa II recognizes only the unmethylated CCGG sequence. Two Msp I sites located at -600 and +200 nucleotides, respectively, from the transcriptional initiation site were unmethylated in DNA from the THP-1, whereas these sites were methylated in the one from the HL-60. Treating the HL-60 cells with 1,25-vitamin D3, ( 1,25-(OH)2D3), which is known to induce monocytic cell differentiation, induce demethylation of the sites, suggesting the methylation status was correlated with the differentiation stages of monocytes.

Base Sequence↗
PubMed1996

Tumor necrosis factor microsatellites define a Crohn's disease-associated haplotype on chromosome 6.

BACKGROUND & AIMS: HLA class II associations have been described in Crohn's disease (CD) and ulcerative colitis (UC) and may be markers for other closely linked genes that are involved in disease pathogenesis. The tumor necrosis factor (TNF) locus, which contains the genes for TNF-alpha and TNF-beta, is located on chromosome 6 within the major histocompatibility complex loci. To investigate potential genetic associations in inflammatory bowel disease at the TNF locus, we studied 75 patients with CD, 73 patients with UC, and 60 ethnically matched controls using microsatellite markers. METHODS: Five TNF microsatellite loci (TNFa, TNFb, TNFc, TNFd, and TNFe) were typed using polymerase chain reaction. RESULTS: A CD-associated allelic combination, TNFa2b1c2d4e1, was found in 24% of patients with CD, 4.1% of patients with UC (P=0.001; odds ratio, 7.4; CD vs. UC), and 6.7% of control subjects (P=0.01; odds ratio, 4.4 CD vs. controls). This TNF haplotype was associated with the previously described HLA-DR1/DQ5 combination in CD. CONCLUSIONS: The TNFa2b1c2d4e1 allelic combination is the strongest genetic risk factor described in CD and, with HLA class II alleles, defines a group of markers on chromosome 6 that extends from HLA class II to upstream of the TNF-beta gene.

Alleles↗
PubMed1996

The Agrobacterium tumefaciens virB7 gene product, a proposed component of the T-complex transport apparatus, is a membrane-associated lipoprotein exposed at the periplasmic surface.

The Agrobacterium tumefaciens virB7 gene product contains a typical signal sequence ending with a consensus signal peptidase II cleavage site characteristic of bacterial lipoproteins. VirB7 was shown to be processed as a lipoprotein by (i) in vivo labeling of native VirB7 and a VirB7::PhoA fusion with [3H]palmitic acid and (ii) inhibition of VirB7 processing by globomycin, a known inhibitor of signal peptidase II. A VirB7 derivative sustaining a Ser substitution for the invariant Cys-15 residue within the signal peptidase II cleavage site could not be visualized immunologically and failed to complement a delta virB7 mutation, establishing the importance of this putative lipid attachment site for VirB7 maturation and function. VirB7 partitioned predominantly with outer membrane fractions from wild-type A348 cells as well as a delta virB operon derivative transformed with a virB7 expression plasmid. Expression of virB7 fused to phoA, the alkaline phosphatase gene of Escherichia coli, gave rise to high alkaline phosphatase activities in E. coli and A. tumefaciens cells, providing genetic evidence for the export of VirB7 in these hosts. VirB7 was shown to be intrinsically resistant to proteinase K; by contrast, a VirB7::PhoA derivative was degraded by proteinase K treatment of A. tumefaciens spheroplasts and remained intact upon treatment of whole cells. Together, the results of these studies favor a model in which VirB7 is topologically configured as a monotopic protein with its amino terminus anchored predominantly to the outer membrane and with its hydrophilic carboxyl domain located in the periplasmic space. Parallel studies of VirB5, VirB8, VirB9, and VirB10 established that each of these membrane-associated proteins also contains a large periplasmic domain whereas VirB11 resides predominantly or exclusively within the interior of the cell.

Agrobacterium tumefaciens↗
PubMed1996

The Agrobacterium tumefaciens VirB7 lipoprotein is required for stabilization of VirB proteins during assembly of the T-complex transport apparatus.

The Agrobacterium tumefaciens virB7 gene product is a lipoprotein whose function is required for the transmission of oncogenic T-DNA to susceptible plant cells. Three lines of study provided evidence that VirB7 interacts with and stabilizes other VirB proteins during the assembly of the putative T-complex transport apparatus. First, a precise deletion of virB7 from the pTiA6NC plasmid of wild-type strain A348 was correlated with significant reductions in the steady-state levels of several VirB proteins, including VirB4, VirB9, VirB10, and VirB11; trans expression of virB7 in the delta virB7 mutant partially restored the levels of these proteins, and trans coexpression of virB7 and virB8 fully restored the levels of these proteins to wild-type levels. Second, modulation of VirB7 levels resulted in corresponding changes in the levels of other VirB proteins in the following cell types: (i) a delta virB7 mutant expressing virB7 and virB8 from isopropyl-beta-D-thiogalactopyranoside (IPTG)-inducible Plac and other virB genes from acetosyringone (AS)-inducible PvirB; (ii) a delta virB operon mutant expressing virB7 and virB8 from Plac and virB9, virB10, and virB11 from PvirB; and (iii) a delta virB operon mutant expressing virB7 from IPTG-inducible Pklac and virB9 from an AS-inducible PvirB. Third, the synthesis of a VirB7::PhoA fusion protein in strain A348 was correlated with a significant reduction in the steady-state levels of VirB4, VirB5, and VirB7 through VirB11; these cells also exhibited a severely attenuated virulence phenotype, indicating that synthesis of the fusion protein perturbs the assembly of VirB proteins into a stabilized protein complex required for T-complex transport. Extracts of AS-induced cells electrophoresed under nonreducing conditions possessed undetectable levels of the 32-kDa VirB9 and 4.5-kDa VirB7 monomers and instead possessed a 36-kDa complex that cross-reacted with both VirB7 and VirB9 antisera and accumulated as a function of virB7 expression. Our results are consistent with a model in which VirB7 stabilizes VirB9 by formation of a covalent intermolecular cross-link; in turn, the VirB7-VirB9 heterodimer promotes the assembly of a functional T-complex transport machinery.

Agrobacterium tumefaciens↗
PubMed1996

Stable renal function in insulin-dependent diabetes mellitus 10 years after nephrotic range proteinuria.

It has been considered unlikely that patients with insulin-dependent diabetes and diabetic nephropathy with nephrotic range proteinuria can substantially reduce proteinuria and continue for many years without further loss of renal function. We present a patient who had the diagnosis of insulin-dependent diabetes made at age 15, had his first of 6 laser treatments for proliferative and hemorrhagic retinopathy at age 27 and was found to have nephrotic range proteinuria and edema with hypertension at age 29, when results of a renal biopsy were typical of diabetic nephropathy. Ten years later, with the last 5.5 years on ACE inhibitors, proteinuria has been < 0.65 g/24 h for 2 years and recently 0.22 g, serum creatinine is unchanged at 90 to 102 mu mol/l, DTPA GFR is 104 ml/min and retinopathy has remained stable without laser therapy for 7 years. Blood pressure on clinic visits has averaged 126/74 for the last 8 years. This duration of stable renal function and the major decrease in proteinuria after being in the neprotic range is very rare in reports, if not unique.

Adult↗
PubMed1994

Treatment of acute diarrhea with oral rehydration solutions containing glutamine.

OBJECTIVE: In a randomized, double-blind, controlled clinical trial we compared the efficacy of adding 90 mmol/L L-glutamine to the standard World Health Organization oral rehydration salts (WHO-ORS). SUBJECTS: One hundred twenty male infants, > 1 month and < 1 year of age, with acute non-cholera diarrhea and dehydration were randomly assigned to one of the two treatment groups. METHODS: Patients were kept in a metabolic unit where body weight, ORS, water and food intake, as well as stool, urine and vomitus output were recorded at 6-hour intervals. Laboratory evaluation, including blood gases and electrolytes, were monitored during hospitalization. RESULTS: Diarrheal stool output, duration of diarrhea and volume of ORS required to achieve and maintain hydration was not significantly different between the treatment groups. CONCLUSION: This study demonstrated that a glutamine-based ORS did not provide any additional therapeutic advantage over the standard WHO-ORS during treatment of dehydration in infants with acute non-cholera diarrhea.

Acute Disease↗
PubMed1994

Molecular characterization of races and vegetative compatibility groups in Fusarium oxysporum f. sp. vasinfectum.

Restriction fragment length polymorphism (RFLP) and vegetative compatibility analyses were undertaken to assess genetic relationships among 52 isolates of Fusarium oxysporum f. sp. vasinfectum of worldwide origin and representing race A, 3, or 4 on cotton plants. Ten distinct vegetative compatibility groups (VCGs) were obtained, and isolates belonging to distinct races were never in the same VCG. Race A isolates were separated into eight VCGs, whereas isolates of race 3 were classified into a single VCG (0113), as were those of race 4 (0114). Ribosomal and mitochondrial DNA (rDNA and mtDNA) RFLPs separated four rDNA haplotypes and seven mtDNA haplotypes. Race A isolates displayed the most polymorphism, with three rDNA haplotypes and four mtDNA haplotypes; race 4 isolates formed a single rDNA group but exhibited three mtDNA haplotypes, while race 3 isolates had unique rDNA and mtDNA haplotypes. Two mtDNA molecules with distinct sizes were identified; the first (45-kb mtDNA) was found in all race A isolates and seven race 4 isolates, and the second (55-kb mtDNA) was found in all race 3 isolates and in two isolates of race 4. These two mtDNA molecules were closely related to mtDNAs of F. oxysporum isolates belonging to other formae speciales (conglutinans, lycopersici, matthioli, and raphani). Isolates within a VCG shared the same rDNA and mtDNA haplotypes, with the exception of VCG0114, in which three distinct mtDNA haplotypes were observed. Genetic relationships among isolates inferred from rDNA or mtDNA site restriction data were different, and there was not a strict correlation between race and RFLPs.(ABSTRACT TRUNCATED AT 250 WORDS)

DNA, Fungal↗
PubMed1994

Developmental changes of pyroglutamate-peptidase I activity in several regions of the female and the male rat brain.

In this work, we have described decreases of pGlu-peptidase I activity, detected using pGlu-beta-naphtylamide as substrate, from 9 to the 20 days after birth in five brain areas. In addition, we have found sexual differences in the enzyme activity in the hypothalamic-pituitary axis in all ages investigated. pGlu-peptidase cleaves the pGlu-aminoacid bond of several neuropeptides such as thyroliberin, luliberin and neurotensin. The decrease in the activity of pGlu-peptidase coincidents with the increases observed in brain thyroliberin concentration and the decreases in His-Pro diketopiperazine. It is suggested that this enzyme could play a part in the normal development of the rat brain.

Age Factors↗
PubMed1994

Membrane-bound pyroglutamyl-arylamidase activity during the first postnatal month in several rat brain areas.

Membrane-bound pyroglutamyl-aminopeptidase activity cleaves the pyoglutamate amino acid bond of thyroliberin (TRH). Information concerning developmental variations in TRH has been reported. However, little is known about the ontogeny of the membrane-bound enzyme activities capable of hydrolyzing the mentioned tripeptide. In this work we have described decreases in membrane-bound pyroglutamyl-aminopeptidase (arylamidase) activity, from day 9 to day 20 after birth, in the hypothalamus, the striatum, the frontal, occipital and parieto-temporal cortices and the pituitary gland of the male and the female rat. The developmental profile is similar in rats of both sexes. We have not found significative changes between 20 and 25 postnatal days. The observed decreasing activity is developmentally coincident with the increases in thyroliberin and decreases in Hys-Pro diketopiperazine concentration in different brain areas. It is suggested that membrane-bound pyroglutamyl-peptidase activity could play a part in the normal development of thyroliberin physiology.

Aging↗