PubMed Health⌕ Search

Biomedical subjects

L Cortes

Publications and source records attributed to L Cortes.

14 recordsLinked to original sources
PubMed2002

Genotypic characterization of macrolide-resistant strains of Streptococcus pneumoniae isolated in Quebec, Canada, and in vitro activity of ABT-773 and telithromycin.

Increasing resistance of Streptococcus pneumoniae to macrolides represents a challenge for clinicians. New ketolides have an enhanced activity against macrolide-resistant strains. Four hundred and seventy-four strains of S. pneumoniae were collected during the 2000-2001 season in Quebec through a surveillance network. Macrolide resistance was 20.2%, and significantly higher in non-invasive strains versus invasive ones (22.4% versus 14.8%), and in children (30%) versus adults (14.8%). For susceptible strains, MIC(90)s of ABT-773 and telithromycin were 0.008 and 0.015 mg/L. Among the 96 macrolide-resistant strains, 56 (58%) were erm(B), 35 (37%) carried the mef(A) gene, four were carrying both genes and one none. ABT-773 and telithromycin were very active against all these resistant strains irrespective of the resistance mechanism, with MIC(90)s of 0.25 and 0.5 mg/L, respectively.

Adolescent↗
PubMed2000

A randomized comparison of once versus twice daily recombinant human granulocyte colony-stimulating factor (filgrastim) for stem cell mobilization in healthy donors for allogeneic transplantation.

To evaluate the schedule dependency of granulocyte colony-stimulating factor (G-CSF) (filgrastim) for stem cell mobilization, we conducted a randomized comparison in 50 healthy donors, with one subcutaneous daily injection of 10 microg/kg G-CSF (n = 25) compared with twice injections daily of 5 microg/kg G-CSF (n = 25). The two groups were well balanced for age, body weight and sex. G-CSF application was performed on an out-patient basis and leukapheresis was started in all donors on day 5. The most frequent side-effects of G-CSF were mild to moderate bone pain (88%), mild headache (72%), mild fatigue (48-60%) and nausea (8%) without differences between the two groups. The CD34(+) cell count in the first apheresis was 5.4 x 10(6)/kg donor weight (range 2.8-13.3) in the 2 x 5 microg/kg group compared with 4.0 x 10(6)/kg (range 0.4-8.8) in the 1 x 10 microg/kg group (P = 0.007). The target of collecting > 3.0 x 10(6) CD34(+) cells/kg donor weight with one apheresis procedure was achieved in 24/25 (96%) donors in the 2 x 5 microg/kg group and in 17/25 (68%) donors in the 1 x 10 microg/kg group. The target of collecting > 5.0 x 10(6) CD34(+) cells/kg in the first apheresis was achieved in 64% in the 2 x 5 microg/kg group, but in only 36% in the 1 x 10 microg/kg group. The progenitor cell assay for granulocyte-macrophage colony-forming units (CFU-GM) and erythroid burst-forming units (BFU-E) was higher in the 2 x 5 microg/kg group than in the 1 x 10 microg/kg group (7.0 vs. 3.5 x 10(5)/kg, P = 0.01; 6.6 vs. 5.0 x 10(5)/kg; P = 0.1). Administering G-CSF (filgrastim) at a dosage of 5 microg/kg twice daily rather than 10 microg/kg once daily is recommended; this leads to a higher CD34(+) cell yield and requires fewer apheresis procedures without increasing toxicity or cost.

Adult↗
PubMed1998

Identification and proteolytic processing of procardosin A.

Plant aspartic proteinases contain a plant-specific insert (PSI) of about 100 amino acids of unknown function with no similarity with the other aspartic proteinases but with significant similarity with saposins, animal sphingolipid activator proteins. PSI has remained elusive at the protein level, suggesting that it may be removed during processing. To understand the molecular relevance of PSI, the proteolytic processing of cardosin A, the major aspartic proteinase from the flowers of cardoon (Cynara cardunculus L.) was studied. Procardosin A, a 64-kDa cardosin A precursor containing PSI and the prosegment was identified by immunoblotting using monospecific antibodies against PSI and the prosegment. Procardosin A undergoes proteolytic processing as the flower matures. PSI was found to be removed before the prosegment, indicating that during processing the enzyme acquires a structure typical of mammalian or microbial aspartic proteinase proforms. In vitro studies showed that processing of PSI occurs at pH 3.0 and is inhibited by pepstatin A and at pH 7.0. Sequence analysis allowed the identification of the cleavage sites, revealing that PSI is removed entirely, probably by an aspartic proteinase. Cleavage of the PSI scissile bonds requires, however, a conformation specific to the precursor since isolated cardosins and pistil extracts were unable to hydrolyse synthetic peptides corresponding to the cleavage sites. In view of these results, a model for the proteolytic processing of cardosin A is proposed and the molecular and physiological relevance of PSI in plant aspartic proteinase is discussed.

Aspartic Acid Endopeptidases↗
PubMed1996

Clinical correlates of chronic rejection in pediatric renal transplantation. A report of the North American Pediatric Renal Transplant Cooperative Study.

A total of 1699 patients with living donor transplants and 1795 patients with cadaver donor transplants entered between January 1987 and November 1994 in the North American Pediatric Renal Transplant Cooperative Study registry form the cohort for this report. Failure from chronic rejection occurred in 76 (4.5%) of living donor transplants and 149 (8.3%) of cadaver transplants. Chronic rejection is the leading cause of graft failure, with 27% of living donor and 26.7% of cadaver donor graft failures attributed to chronic rejection. Univariate and multivariate analyses of various risk factors revealed acute rejection (relative risk [RR]=3.1, P<0.001) and greater than two acute rejections (RR=4.3, P<0.001)to be the most common correlates of chronic rejection. Additionally, late initial acute rejection (>365 days; RR=2.3, P<0.001) was also correlated. Cadaver donor source (RR=1.6, P=0.001) and African-American race (RR=1.6, P<0.003) were weaker but significant risk factors. An analysis of cyclosporine dosing revealed tht a dose of <5mg/kg/day at day 30 was also a risk factor (RR=1.5, P=0.027). Our study concludes that acute rejection is the single most critical element in the genesis of chronic rejection. Thus, measures to prevent the first episode of acute rejection could ameliorate the incidence of chronic rejection.

Adolescent↗
PubMed1996

A longitudinal study of the natural history of growth post-transplantation.

We have evaluated 587 patients with a functioning renal allograft for at least 54 months in whom baseline and continuous bi-annual height measurements were available. All height data were converted into SD score (SDS) or Z-score using normative tables. The results obtained in these patients were compared to our previous data collected at two years (N = 300) and three years (N = 412) post-transplantation. The demography of the study groups in the three time periods was similar. The height deficit in the first study was -2.41; it was -2.46 at the end of the second study period and was -2.29 at the end of the third study period. Children in the first study period had an improvement in height SDS (delta Z) of +0.18, of +0.16 in the second period, and of +0.11 at the end of the third study period. When improvement in height SD was evaluated by donor source, no differences were noted between living related and cadaver donor transplants. Analysis of height SDS by race revealed that, whereas for Caucasian children a steady improvement of 0.18 was noted during both second and third study periods, there was actual deceleration of growth for the African-American and Hispanic children at the end of the third study period (P < 0.02). Multivariate analysis showed that only initial height deficit and recipient age were independent predictors of improved height post-transplantation. Catch up growth, defined as an improvement of 1 SDS, was seen only in those with the greatest deficit or in children 0 to 1 year of age. Overall, catch up growth was seen in only 47% of 2 to 5 year olds. For children over the age of six years who form 72% of the total study cohort, little catch up growth was noted. Our long-term studies reveal that in the first years post-transplantation, when renal function is still stable, height acceleration does not occur in most of the children over the age of six years, and alternative strategies are necessary to improve the quality of life of these children.

Adolescent↗
PubMed1995

Pediatric renal transplantation.

Renal transplantation in children is now a well established mode of optimal therapy for children with end-stage renal disease. The cooperative endeavors of the pediatric renal transplant physicians in the USA and Canada have generated a large volume of data that lends itself to rigorous scientific analysis. With changing practice patterns, the percentage 1- and 2-year graft survivals for cadaveric donor pediatric renal transplants have increased to 83 and 78%, respectively, in 1991 compared with 72 and 65% in 1987. Graft failure from acute irreversible rejection continues to take its toll in children under the age of 6 years. With funding from the National Institutes of Health a major cooperative effort has been organized by the North American Pediatric Renal Transplant Cooperative Study to determine the mechanisms that lead to heightened immune response in young children. Surveillance biopsies done in the early post-transplant days will attempt to identify the molecular mediators of acute rejection. Rehabilitation of children will not be satisfactory without accelerated growth after transplantation. Unfortunately, the longitudinal studies of the natural histories of growth after transplantation demonstrates that catch up growth occurs only in a subset of young children and that for the majority of older children, intervention with recombinant growth hormone is necessary. However, concern regarding the potential of recombinant growth hormone to induce chronic rejection necessitates a controlled trial.

Adolescent↗
PubMedDate not supplied

A newborn with nodular ulcerated lesion on a giant congenital nevus.

The proliferative nodule is a lesion that develops within a congenital nevus. It is usually small (less than 5 mm), sometimes multiple, with a slow growth rate, and has a black or dark brown, smooth, shiny surface. It usually involutes spontaneously. We report a newborn infant who, at birth, had a giant congenital nevus with a nodular, ulcerative, hemorrhagic lesion within it. Physical and neurologic examinations were normal. Radiologic studies at birth and subsequently were normal. A fragment of the lesion was biopsied and histologic findings were compatible with a diagnosis of proliferative nodule in a giant congenital nevus. The rest of the nodule regressed spontaneously after 4 months.

Diagnosis, Differential↗
PubMedDate not supplied

Clinical characteristics at initial presentation and impact of dual therapy on the outcome of bacteremic Streptococcus pneumoniae pneumonia in adults.

BACKGROUND: Approximately 10% of patients hospitalized with community-acquired pneumonia (CAP) are bacteremic. Bacteremic Streptococcus pneumoniae pneumonia (BSPP) is the number one cause of mortality, representing up to 70% of all CAP deaths. In fact, all CAP guidelines have identified this issue as one of the most important issues when establishing their recommendations. OBJECTIVE: To assess the impact of dual antibiotic therapy in patients with BSPP. PATIENTS AND METHODS: All cases of BSPP in patients 18 years of age and older who were hospitalized from 1995 to 2000 were retrospectively analyzed. The standard initial therapeutic regimen used was cefuroxime with or without a macrolide from 1995 to 1997, and ceftriaxone and azithromycin or clarithromycin from 1998 to 2000. During the 1995 to 1997 period, only 16% of the patients initially received a macrolide, whereas all patients in the 1998 to 2000 period received a macrolide at admission. RESULTS: Ninety-five patients (49 men, 46 women) with a mean age of 63 years (range 20 to 98 years) were included in the present study. The mean pneumonia severity index at admission was 113 for the monotherapy cohort and 114 for the dual therapy group. At admission, 30.5% of patients had a leukocyte count greater than 20 109/L, 11.5% had a systolic blood pressure less than 90 mmHg, 44.2% had a respiratory rate greater than 30 breaths/min and 33.6% had nausea/vomiting, necessitating some form of therapy or preventing the patient from eating. In addition, 16.8% had no fever at admission. Overall, 72.5% became afebrile within 48 h. Fifteen (15.8%) patients died (four within the first 72 h). The mortality rate was significantly higher in the monotherapy group (11 of 42 patients; 25.6%) than in the dual therapy cohort (four of 53 patients; 7.5%) (OR 0.23; 95% CI 0.07 to 0.74). Antibiotic resistance was not associated with increased mortality. CONCLUSION: The combination of ceftriaxone plus a macrolide significantly reduced the mortality rate compared with monotherapy (cefuroxime) in patients with CAP that have the highest mortality rate.

Adult↗