Search PubMed⌕ Search

Biomedical subjects

A Torres

Publications and source records attributed to A Torres.

At least 55 records · Page 3Linked to original sources
PubMed2005

[Complications of craniofacial resection in anterior skull base tumors].

INTRODUCTION: The development of new radiographic techniques and the refinement of microsurgery and reconstructive surgery have been the responsible of the establishment of craniofacial resection (CFR) as the standard treatment of anterior skull base tumors. Overall complication rates varies from 24-56%, according to a review of recently published series. OBJECTIVES: To describe the complications of CFR in a series of 41 patients and to analyze the management and final outcome. MATERIAL AND METHODS: From 1990 to 2002, 41 patients underwent CFR for tumors involving the anterior cranial base. The extent of the tumor was always assessed with craniofacial CT-scan and MRI. The objective of the surgical treatment was to achieve "on block" removal of the tumor. RESULTS: The average age was 57 years with a male preponderance (63.4%). Squamous cell carcinoma was the most frequent histopathological type of tumor. The tumors were localized in paranasal sinuses in 78% of the cases. Bifrontal craniotomy was performed in 85.4% and unilateral orbitofrontal craniotomy in 14.6% of the cases. The area of facial resection included: ethmoidectomy (60.9%), ethmoido-sphenoidectomy (24.3%), maxillectomy (39%) and orbital exenteration (14.6%). The reconstruction of the floor of the anterior cranial fossa was performed using pedicled pericranial flap (100%), local (34.1%) or microvascular free flaps (21.9%) and split calvarian graft (19.5%). 20 patients (48.7%) developed post-operative complications, CSF leaks (12.1%) and meningitis (7.3%) being the most frequent major complications. The mortality rate was 7.3%. CONCLUSIONS: CFR has become the standard approach for anterior cranial base tumors. Despite its widespread application, the complication's rate ranges between 24-50% and the procedure carries a risk of significant morbidity and even mortality. Improvement of specific aspects of surgical technique and more refined reconstructive methods will decrease the number of complications.

Adolescent↗
PubMed2004

Transcriptional silencing of the Dickkopfs-3 (Dkk-3) gene by CpG hypermethylation in acute lymphoblastic leukaemia.

DKK-3: is a newly characterised mortalisation-related gene and an antagonist of the Wnt oncogenic signalling pathway whose expression is decreased in a variety of cancer cell lines, suggesting that the Dkk-3 gene, located at chromosome 11p15.1, functions as a tumour suppressor gene. Although 11p15 is a 'hot spot' for methylation in acute lymphoblastic leukaemia (ALL), the role of Dkk-3 abnormalities has never been evaluated in this disease. We analysed CpG island methylation of the Dkk-3 promoter in six ALL cell lines and 183 ALL patients. We observed Dkk-3 hypermethylation in all cell lines and in cells from 33% (60/183) of ALL patients. Moreover, Dkk-3 methylation was associated with decreased Dkk-3 mRNA expression and this expression was restored after exposure to the demethylating agent 5-AzaC. Clinical features did not differ between hypermethylated and unmethylated patients. Estimated disease-free survival (DFS) and overall survival at 10 and 11 years, respectively, were 49.8 and 45.6% for normal patients and 10.5 and 15.1% for hypermethylated patients (P=0.001 and 0.09). Multivariate analysis demonstrated that Dkk-3 methylation was an independent prognostic factor predicting DFS (P=0.0009). Our data suggest that Dkk-3 methylation occurs at an early stage in ALL pathogenesis and probably influences the clinical behaviour of the disease.

Adaptor Proteins, Signal Transducing↗
PubMed2004

Relationship between 3p deletions and telomerase activity in non-small-cell lung cancer: prognostic implications.

3p deletions and telomerase reactivation are two of the most frequent events described in relation to non-small-cell lung cancer (NSCLC) pathogenesis. Moreover, a number of genes that map on 3p have been proposed as candidates to tumour-suppressor genes of importance in the lung cancer process. In this work, we analysed deletions at different 3p loci in relationship to telomerase activity in 66 NSCLCs obtained from patients who had suffered potentially curative surgery. Also, we evaluated prognostic implications. DNA samples were analysed for 3p deletions using five different polymorphic human dinucleotide repeat DNA markers (D3S1619 at 3p22.2, D3S3623 at 3p22.1, D3S1260 at 3p21.33, D3S3697 at 3p14.3, and D3S3722 at 3p21.2). Telomerase activity was investigated by a TRAP-based method. Possible correlations between the different molecular markers and distributions of disease-free survival were estimated. Our data revealed a significant correlation between telomerase activity and losses of heterozygosity (LOH) on D3S3697 (P=0.040), since all of the tumours showing deletion at this locus were positives for telomerase. Moreover, our results revealed clear associations with poor prognosis of patients, in the case of LOH at D3S1260 and D3S3697 (P=0.005 and 0.005, respectively). According to our data, potential repressors for telomerase may be located in chromosome 3p.

Aged↗
PubMed2004

FK506 sensitizes mammalian cells to high osmolarity by modulating p38 MAP kinase activation.

The immunosuppressants tacrolimus (FK506) and cyclosporin A (CsA) have increased the survival rates in organ transplantation. Both drugs inhibit the protein phosphatase calcineurin (CaN) in activated T cells, exhibiting similar side-effects. Diabetes is observed more often in FK506 than CsA therapy, probably due to inhibition of new molecular targets other than CaN. We studied FK506 toxicity in mammalian cells. FK506, but not CsA, regulated p38 activation by osmotic stress, and decreased viability in osmostressed cells. In addition, FK506 treatment strongly increased the phosphorylation of the eukaryotic initiation factor-2alpha (eIF-2alpha) subunit. eIF-2alpha phosphorylation, p38 inhibition and cell lethality were relieved by addition of excess amino acids to the medium, suggesting that amino acid availability mediated FK506 toxicity. Therefore, these FK506-dependent responses could be relevant to the non-therapeutic effects of FK506 therapy.

Calcineurin↗
PubMed2004

Role of apolipoprotein E epsilon 4 allele on chronic allograft nephropathy after renal transplantation.

Lipid abnormalities may contribute to chronic allograft nephropathy (CAN). Apolipoprotein E (ApoE) gene polymorphism regulates lipoprotein metabolism, but little is known about an association between CAN and this polymorphism. The ApoE gene (E3/E4) polymorphism was typed by PCR assay (99 E3/E3, 28 E3/E4, 1 E4/E4) on 128 consecutive renal transplant patients with functioning grafts for more than 3 years (6.7 +/- 2.8 years). Twenty-eight patients with histological CAN were compared with 100 patients who had no clinical evidence of chronic rejection (no proteinuria and sCr < 2.5 mg%). As expected, univariate analysis revealed that patients with CAN experienced a greater acute rejection rate (78% vs 21%; P=.001), a higher serum creatinine (3.6 +/- 1.7 vs 1.4 +/- 0.5 mg%; P=.0001), and an older organ donor (43 +/- 20 vs 29 +/- 13 years; P=.0001). The lipid profiles (total cholesterol and triglycerides levels) were similar in both groups with 60% in each group receiving anti-lipemic drugs. Interestingly, the ApoE epsilon 4 allele was overrepresented in the group with CAN (39% vs 17%, P=.019). Logistic regression analysis showed that the epsilon 4 allele was an independent predictor of CAN (OR: 3.4; CI 95%: 1.07 to 11; P=.040) as were donor age and acute rejection episodes. In conclusion, an interaction between risk factors and genetic factors may determine CAN in this population. This finding may help to target prophylactic interventions in these recipients.

Adult↗
PubMed2004

[Spinal epidural hematomas. Prognostic factors in a series of 22 cases and a proposal for management].

INTRODUCTION: Spontaneous and non-spontaneous spinal epidural hematoma (SEH) is a rare condition in neurosurgical practice. It presents as an acute spinal cord compression and usually requires emergent surgical decompression. Recently non-surgical treatment (corticoid therapy) has been proposed in selected cases of SEH with good neurological recovery. OBJECTIVES: To identify the prognostic factors of this condition. A treatment management based upon our results is proposed. MATERIAL AND METHODS: Between 1985 and 2001, 22 patients suffering SEH were treated at our Department. Age, sex, initial neurological condition (evaluated using the Frankel grading scale), surgical timing, radiological data such as location, extension and degree of radiological cord compression, anticoagulation or antiplatelet therapy, epidural anesthesia and previous spinal surgery were analyzed in order to find prognostic factors. Finally, conservative or surgical treatment as well as final neurological condition were also considered for the analysis. RESULTS: The average age was 69 years with a male preponderance (72.7%). Surgical decompression was done in 17 cases, most of them (11 cases) presenting with high neurological deficit (Frankel A-B). Conservative treatment was used on 5 patients. Operated patients showed a larger degree of neurological recovery. The incidence of post-operative complications was of 13%. CONCLUSIONS: This study shows the efficiency of SEH surgical evacuation performed within the first 24 hours, particularly when the patient presents a severe neurological deficit (Frankel A-B). Patients presenting minimal neurological involvement (Frankel D-E) can be managed successfully with conservative treatment.

Adult↗
PubMed2004

Comparison of urinary sphingolipids in human populations with high and low maize consumption as a possible biomarker of fumonisin dietary exposure.

The increased sphinganine/sphingosine (SA/SO) ratio has previously been shown as a biomarker of fumonisin exposure in experimental animals and has been proposed as a tool to assess human exposure to fumonisin mainly occurring through the dietary consumption of fumonisin contaminated maize-based foods. Sphinganine and sphingosine were measured in urines of humans resident in two areas of North Argentina and South Brazil with high maize consumption and compared with urine samples collected in areas with very low or no maize consumption, such as Central Argentina and Southern Italy. The pattern of SA/SO values in the two groups with no maize consumption (assumed as controls) was similar, with all SA/SO values lower than one. Mean SA/SO ratio was 1.27 in urine of subjects with high maize consumption (n = 123) and 0.36 in controls (n = 66) and the difference was statistically significant (p<0.001). The mean fumonisin level in maize samples collected in North Argentina and South Brazil was 0.35 mg kg(-1) (n = 40). Although a similar maize and fumonisin intake was recorded for the two groups of populations, the mean SA/SO ratio in South Brazil (1.57) was significantly higher (p<0.05) than that of North Argentina (0.69). These data suggest that the higher SA/SO values observed in South Brazil cannot be associated with high fumonisin exposure and further studies are necessary to provide convincing evidence for using the SA/SO ratio as a biomarker of human fumonisin exposure.

Adolescent↗
PubMed2004

Validation of predictive rules and indices of severity for community acquired pneumonia.

BACKGROUND: A study was undertaken to validate the modified American Thoracic Society (ATS) rule and two British Thoracic Society (BTS) rules for the prediction of ICU admission and mortality of community acquired pneumonia and to provide a validation of these predictions on the basis of the pneumonia severity index (PSI). METHOD: Six hundred and ninety six consecutive patients (457 men (66%), mean (SD) age 67.8 (17.1) years, range 18-101) admitted to a tertiary care hospital were studied prospectively. Of these, 116 (16.7%) were admitted to the ICU. RESULTS: The modified ATS rule achieved a sensitivity of 69% (95% CI 50.7 to 77.2), specificity of 97% (95% CI 96.4 to 98.9), positive predictive value of 87% (95% CI 78.3 to 93.1), and negative predictive value of 94% (95% CI 91.8 to 95.8) in predicting admission to the ICU. The corresponding predictive indices for mortality were 94% (95% CI 82.5 to 98.7), 93% (95% CI 90.6 to 94.7), 49% (95% CI 38.2 to 59.7), and 99.5% (95% CI 98.5 to 99.9), respectively. These figures compared favourably with both the BTS rules. The BTS-CURB criteria achieved predictions of pneumonia severity and mortality comparable to the PSI. CONCLUSIONS: This study confirms the power of the modified ATS rule to predict severe pneumonia in individual patients. It may be incorporated into current guidelines for the assessment of pneumonia severity. The CURB criteria may be used as an alternative tool to PSI for the detection of low risk patients.

Adult↗
PubMed2004

Risk factors of treatment failure in community acquired pneumonia: implications for disease outcome.

BACKGROUND: An inadequate response to initial empirical treatment of community acquired pneumonia (CAP) represents a challenge for clinicians and requires early identification and intervention. A study was undertaken to quantify the incidence of failure of empirical treatment in CAP, to identify risk factors for treatment failure, and to determine the implications of treatment failure on the outcome. METHODS: A prospective multicentre cohort study was performed in 1424 hospitalised patients from 15 hospitals. Early treatment failure (<72 hours), late treatment failure, and in-hospital mortality were recorded. RESULTS: Treatment failure occurred in 215 patients (15.1%): 134 early failure (62.3%) and 81 late failure (37.7%). The causes were infectious in 86 patients (40%), non-infectious in 34 (15.8%), and undetermined in 95. The independent risk factors associated with treatment failure in a stepwise logistic regression analysis were liver disease, pneumonia risk class, leucopenia, multilobar CAP, pleural effusion, and radiological signs of cavitation. Independent factors associated with a lower risk of treatment failure were influenza vaccination, initial treatment with fluoroquinolones, and chronic obstructive pulmonary disease (COPD). Mortality was significantly higher in patients with treatment failure (25% v 2%). Failure of empirical treatment increased the mortality of CAP 11-fold after adjustment for risk class. CONCLUSIONS: Although these findings need to be confirmed by randomised studies, they suggest possible interventions to decrease mortality due to CAP.

Adolescent↗
PubMed2004

Inflammatory response associated with pulmonary complications in non-HIV immunocompromised patients.

BACKGROUND: A study was undertaken to evaluate the local and systemic inflammatory response associated with pulmonary complications in immunocompromised patients and potential implications regarding severity and prognosis. METHODS: Levels of different inflammatory mediators were measured in the bronchoalveolar lavage (BAL) fluid and serum on days 1 and 4 after the identification of the pulmonary complication in 127 patients with different immunosuppressive conditions. RESULTS: Pulmonary complications were characterised by a high percentage of neutrophils and increased levels of tumour necrosis factor (TNF)-alpha, interleukin (IL)-6, IL-8 and IL-10 in the BAL fluid and high serum levels of TNF-alpha, IL-6, and plasma C-reactive protein (CRP). The inflammatory response was similar in the different groups of immunocompromised patients evaluated. The levels of proinflammatory cytokines were higher in patients with pulmonary infections, particularly those of bacterial aetiology. Patients with a more severe pulmonary infection had a more intense local and systemic inflammatory response. A BAL fluid IL-6 level of >40 pg/ml was an independent predictor of mortality (OR 4.65, 95% CI 1.3 to 16.1), together with a need for mechanical ventilation (OR 13.5, 95% CI 3.2 to 57.3). Patients who died had persistently high levels of CRP on day 4. CONCLUSIONS: The evaluation of the inflammatory response, particularly the determination of IL-6 levels in the BAL fluid and CRP in the serum, may be useful for deciding the appropriate management of pulmonary complications in immunocompromised patients.

Adult↗
PubMed2004

[Membranoproliferative glomerulonephritis associated with autoimmune thyroiditis].

Several cases of glomerular disease have been associated to thyroid diseases. The most frequent lesion described is membranous glomerulopathy, presented as a nephrotic syndrome. Here we report a 67-year-old man who developed a nephrotic syndrome accompanied by rapid derangement of renal function shortly after the onset of a primary hypothyroidism due to autoimmune thyroiditis. High titers of circulating anti-thyroglobulin and anti-microsomal thyroid antigen antibodies were detected. Serum levels of C3 and C4 fractions of complement were markedly decreased. Renal biopsy showed a membranoproliferative glomerulonephritis with severe mesangial proliferation, a type of glomerular involvement non-described previously in the literature, in relation with thyroid diseases. Four boluses of intravenous steroids were administered, followed by oral prednisone for three months. A dramatic recovery of renal function, together with normalization of urinary sediment, proteinuria decrease and normalization of serum complement were observed. Three years later, the patient suffered from a similar event, with a positive response to steroids again. One year later, the patient had a new recurrence and was treated with mycophenolate mofetil , improving his clinical situation.

Aged↗
PubMed2004

[Acute renal failure in a patient with myelodysplastic syndrome and paroxysmal nocturnal hemoglobinuria phenotype].

Hemoglobin and myoglobin heme pigments and iron have acute and chronic nephrotoxic effects, which are often associated with massive hemolysis and rhabdomyolysis. We report a patient with a myelodysplastic syndrome and paroxysmal nocturnal hemoglobinuria phenotype who developed an acute renal failure after a severe haemolytic crisis. There was not evidence of renal vascular pathology, urinary tract obstruction or prerenal factors. Renal biopsy showed features of acute tubular necrosis, with extended iron deposits in tubule cell cytoplasm and tubulo-interstitial fibrosis and atrophy. The patient was oliguric requiring hemodialisys during three weeks, recovering renal function on the fourth week after admission. This case underlines the nephrotoxic role of heme pigment and iron, and possible pathophysiologic mechanisms involved in acute and chronic toxicity of both agents are reviewed.

Acute Kidney Injury↗
PubMed2004

Diversity and species composition of sand flies (Diptera: Psychodidae) in a Venezuelan urban focus of cutaneous leishmaniasis.

The present study examined the spatial and temporal abundance and diversity of phlebotomine sand flies in an area of Venezuela that is an ancient focus of leishmaniasis. The study was conducted in 6 stations in urban localities in Trujillo City, located in northwestern Venezuela (9 degrees 22' 24" N, 70 degrees 26' 08" W), which is located in a mountain range in the Andean ecoregion (altitude = 600-1,010 m). During 1995-99, entomological surveys were conducted after and before the rainy season. Shannon light traps were operated from 1800 to 2000 h in peridomestic site trap locations. Twelve species were captured, and Lutzomyia youngi, L. ovallesi, L. scorzai, L. gomezi, L. lichyi, and L. shannoni occurred at all localities in each year. The abundance of these species showed low variation over time but high variation between localities. The Sørensen similarity index, used to compare diversity between years within each locality, ranged from 0.60 at Carmona to 0.84 at La Hacienda. Sand fly communities exhibited annual variation in species richness and diversity. Variations were affected more by changes in species abundance than by changes in species composition. Lutzomyia ovallesi, L. lichyi, and L. scorzai had the highest coefficient of variation between years (63, 38, and 23%, respectively).

Animals↗