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Biomedical subjects

J Vilardell

Publications and source records attributed to J Vilardell.

At least 37 records · Page 2Linked to original sources
PubMed1996

[Pneumocystis carinii pneumonia in the transplant recipient].

BACKGROUND: The aim of the present was to study the clinical characteristics and prognostic factors of 20 cases of pneumonia by Pneumocystis carinii (NPC) diagnosed over the last 10 years in renal, renopancreatic, liver and bone marrow transplant recipients. METHODS: The clinical histories of all the patients transplanted in the authors' hospital from 1985 to 1994 who developed NPC were analyzed. Diagnosis was established by visualization of cysts in methenamine silver staining of bronchialveolar lavage (BAL) samples. RESULTS: The global incidence of NPC in our transplant population was 1%. However, the incidence was 3% in the recipients who did not receive prophylaxis. No patient in this series received prophylaxis at the time of diagnosis. Ninety percent of the patients had history or rejection. Pneumonia was observed in 15 (75%) in the first 6 months post transplantation. The mean length of the symptoms prior to diagnosis was 10 days. Ninety-five percent of the patients presented cough, dysnea and fever. Radiology demonstrated diffuse alveolointerstitial infiltrates in 18 patients (90%). Basal arterial PO2 was lower than 60 mmHg in 14 (70%) patients and the alveoloarterial gradient of oxygen was greater than 60 mmHg in 9 (45%). Mechanical ventilation was required in 50% of the patients. BAL demonstrated cytologic alterations compatible with CMV infection in 50% of the cases and in two Aspergillus fumigatus was associated. Mortality was 35%. The only variable significantly associated with bad prognosis was the need for mechanical ventilation (p = 0.003). CONCLUSIONS: The incidence of pneumonia by P. carinii in a population of transplant recipients was 1%. No patient received primary prophylaxis at the time of diagnosis. Most of the episodes were observed during the first 6 months post transplant. Mortality was 35% with the only variable with prognostic significance being the need for mechanical ventilation.

Adolescent↗
PubMed1996

[Chronic myeloid leukemia after renal transplantation: report of a new case and review of the bibliography].

The increase in cancer incidence in renal transplant recipients is a well recognized fact, which has been related to post-transplant immunosuppressive therapy. Solid tumors, skin cancer and non-Hodgkin's lymphomas account for most of the neoplasms in these patients, whereas chronic myeloproliferative disorders are infrequent. A patient is reported who developed chronic myelogenous leukemia (CML) six years after renal transplantation, which was followed by immunosuppressive with azathioprine, and the published data on such an association are reviewed. In all 10 cases reported azathioprine had been administered after transplantation. The amount and type of post-transplant immunosuppressive therapy seems to be the most important risk factor for the development of secondary CML in these patients, since no cases of CML in patients receiving cyclosporine A have been reported.

Adult↗
PubMed1995

Characterization of the pre-mRNA binding site for yeast ribosomal protein L32: the importance of a purine-rich internal loop.

The structure of the RNA binding target for Saccharomyces cerevisiae ribosomal protein L32 was examined using chemical and enzymatic probes as well as thermodynamic methods. In vivo, the production of yeast RPL32 is regulated by a feedback mechanism whereby RPL32 binds to the 5' end of its transcript and inhibits splicing. The binding site of ribosomal protein L32 on the L32 RNA transcript can be reduced to fewer than 30 nucleotides which compromise a stem-internal loop-stem structural motif. The internal loop is closed by a potential G-U pair, is asymmetric and contains mostly purines. The existence of the two helical regions was confirmed by chemical and enzymatic probing. The reactivity of the loop region suggests a structure intermediate between that of single and double-stranded RNA. Base stacking continues into the loop, but two loop bases are extremely reactive to chemical agents. The interaction between the model RNA and the protein is specific and has a dissociation constant of approximately 10 nM. Several of the loop bases are critical for protein binding, as demonstrated by mutational data and chemical protection and modification interference studies. The internal loop destabilizes the RNA, and allows the RNA to melt in an all-or-none fashion.

Aniline Compounds↗
PubMed1994

[138 episodes of bacteremia or fungemia in patients with solid organ (renal or hepatic) transplantation].

BACKGROUND: To study the bacteremias and fungemias of the patients with solid organ transplantation (kidney or liver) and analyze the differences according to the type of graft. METHODS: A prospective study included in a control program of bacteremias of a 1000-bed hospital and a follow up study of the infections of the patients who had undergone kidney transplantation (KT) (1985-1991) and liver transplantation (LT) (1988-1991) were carried out. RESULTS: One hundred thirty-one bacteremias and 5 fungemias, 75 in 62 patients with KT out of a total of 568 transplantations (11%) and 63 out of 54 patients with LT out of a total of 185 transplantations (29%) were identified. The prevalence of bacteremia in LT was greater (p < 0.001). The origin was nosocomial in 95% in LT and 70% in KT (p < 0.001). Around 50% of the bacteremias occurred during the first month post LT and KT. The microorganisms isolated were: Staphylococcus sp. (21 in KT and 30 in LT), with greater incidence in LT (p < 0.05); Enterococcus sp. (9 and 5, respectively), enterobacterias (12 and 12, respectively), Pseudomonas sp. (14 and 6, respectively), Candida sp. (2 and 3, respectively) with similar rates in both transplants. The origin of bacteremia was; renal and urinary tract, most frequent in KT (21 and 2 respectively) (p = 0.001). The origin of bacteremia was: renal and urinary tract, most frequent in KT (21 and 2 respectively) (p < 0.001), intraabdominal and biliary tract, most frequent in LT (4 and 14, respectively) (p = 0.007); intravenous catheter, most frequent in LT (16 and 24 respectively) (p < 0.05); lung, most frequent in LT although without statistical significance (3 and 8, respectively), (p = NS), and finally, surgical wound (4 and 1, respectively) (p = NS). Seventeen patients died (14 with LT and 3 with KT). CONCLUSIONS: The incidence of bacteremia and the mortality related, was greater in LT than that observed in KT. The most frequent origin in KT was the kidney and urinary tract and the biliary and intraabdominal organs and the intravenous catheter were most prevalent in liver transplants. Staphylococcus sp was the most frequent germ in both types of transplantation and polymicrobian infection in liver transplants. Gram-negative germs caused higher mortality in liver transplantation.

Bacteremia↗
PubMed1994

Regulation of the rab17 gene promoter in transgenic Arabidopsis wild-type, ABA-deficient and ABA-insensitive mutants.

The abscisic acid-responsive gene rab17 is induced during maize embryo maturation and in vegetative tissues under water stress conditions. To investigate how ABA is involved in the induction of the rab17 gene, we present here a genetic approach to analyse the transcriptional regulation of the 1.3 kb rab17 promoter fragment in transgenic wild-type Arabidopsis and mutants which are deficient (aba) and insensitive (abi1, abi2 and abi3) to ABA. During seed development the rab17 promoter fragment confers similar temporal and spatial regulation on the reporter gene GUS, both in transgenic wild-type and ABA-deficient and ABA-insensitive mutants. The rab17 promoter was only active in embryo and endosperm during late seed development, although the ABA-deficient embryo mutant showed a reduction in the level of GUS activity. During germination rab17 promoter activity decreases, and GUS activity is not enhanced by water stress in transgenic wild-type and mutant plants. In contrast, transcription of the Arabidopsis endogenous rab gene is stimulated by water stress, both in wild-type and ABA-insensitive mutants. Our data suggest that different molecular mechanisms mediate seed-specific expression and ABA water stress induction of the rab17 gene and indicate strong conservation of the seed-specific regulatory mechanism for rab genes in monocot and dicot plants.

Abscisic Acid↗
PubMed1994

Regulation of splicing at an intermediate step in the formation of the spliceosome.

In vivo experiments have demonstrated that the ribosomal protein L32 of Saccharomyces cerevisiae brings about the inhibition of splicing of the transcript of its own gene through an RNA structure comprised largely of the first exon. We now show that L32, itself, binds specifically to this RNA. Splicing of the RPL32 transcript in vitro is blocked by the presence of L32. Furthermore, addition of the 75-nucleotide RNA representing the 5' end of the RPL32 transcript stimulates specifically the splicing of the RPL32 substrate, presumably by competing for L32 present in the extract. Use of RNAs carrying mutations shown to abolish the regulation of splicing, either as substrates or as competitors, confirmed that the in vitro reaction is a faithful representation of the situation in vivo. We conclude that the regulation of splicing occurs through the specific binding of L32 to an RNA structure within the first 75 nucleotides of the RPL32 transcript. The RPL32 substrate, bound to L32, forms a complex with U1 snRNP, the first step in spliceosome assembly. The presence of L32 prevents the ATP-dependent association of the U2 snRNP necessary to form a complete spliceosome.

Base Sequence↗
PubMed1993

The cis-regulatory element CCACGTGG is involved in ABA and water-stress responses of the maize gene rab28.

The maize gene rab28 has been identified as ABA-inducible in embryos and vegetative tissues. It is also induced by water stress in young leaves. The proximal promoter region contains the conserved cis-acting element CCACGTGG (ABRE) reported for ABA induction in other plant genes. Transient expression assays in rice protoplasts indicate that a 134 bp fragment (-194 to -60 containing the ABRE) fused to a truncated cauliflower mosaic virus promoter (35S) is sufficient to confer ABA-responsiveness upon the GUS reporter gene. Gel retardation experiments indicate that nuclear proteins from tissues in which the rab28 gene is expressed can interact specifically with this 134 bp DNA fragment. Nuclear protein extracts from embryo and water-stressed leaves generate specific complexes of different electrophoretic mobility which are stable in the presence of detergent and high salt. However, by DMS footprinting the same guanine-specific contacts with the ABRE in both the embryo and leaf binding activities were detected. These results indicate that the rab28 promoter sequence CCACGTGG is a functional ABA-responsive element, and suggest that distinct regulatory factors with apparent similar affinity for the ABRE sequence may be involved in the hormone action during embryo development and in vegetative tissues subjected to osmotic stress.

Abscisic Acid↗