Search PubMed⌕ Search

Biomedical subjects

A Torres

Publications and source records attributed to A Torres.

At least 217 records · Page 12Linked to original sources
PubMed2000

Etiology and microbial patterns of pulmonary infiltrates in patients with orthotopic liver transplantation.

STUDY OBJECTIVE: To evaluate the etiology and microbial patterns of pulmonary infiltrates in liver transplant patients using a bronchoscopic diagnostic approach and the impact of diagnostic results on antimicrobial treatment decisions. DESIGN: A prospective cohort study. SETTING: A 1,000-bed tertiary-care university hospital. PATIENTS AND METHODS: Fifty consecutive liver transplant patients with 60 episodes of pulmonary infiltrates (33 episodes during mechanical ventilation) were studied using flexible bronchoscopy with protected specimen brush (PSB) and BAL. RESULTS: A definite infectious etiology was confirmed in 29 episodes (48%). Eighteen episodes corresponded to probable pneumonia (30%), 10 episodes had noninfectious etiologies (17%), and 3 remained undetermined (5%). Opportunistic infections were the most frequent etiology (16/29, 55%, including 1 mixed etiology). Bacterial infections (mainly Gram-negative) accounted for 14 of 29 episodes (48%), including 1 of mixed etiology. The majority of bacterial pneumonia episodes (n = 10, 71%) occurred in period 1 (1 to 28 days posttransplant) during mechanical ventilation, whereas opportunistic episodes were predominant in periods 2 and 3 (29 to 180 days and > 180 days posttransplant, respectively; n = 14, 82%). Microbial treatment was changed according to diagnostic results in 21 episodes (35%). CONCLUSIONS: Microbial patterns in liver transplant patients with pulmonary infiltrates corresponded to nosocomial, mainly Gram-negative bacterial pneumonia in period 1, and to opportunistic infections in period 2 and, to a lesser extent, period 3. A comprehensive diagnostic evaluation including PSB and BAL fluid examination frequently guided specific antimicrobial therapy.

Adolescent↗
PubMed2000

Elastin variations implicating in vascular smooth muscle cells phenotype in human tortuous arteries.

The aim of the present work was to study the morphological implications between the elastin and the phenotypic expression of the vascular smooth muscle cells. For this purpose, sixty human tortuous arteries from different territories have been studied. We have measured the morphometric indexes Intimal Thickening Index and Elastolyse Index and they have been quantified with computer system analysis, image-colour corresponding to the orcein and Verhoëff reactions for detecting elastin and the alpha-actin in the smooth muscle cells. We compared both territorial arteries from the cranial and from abdominal origin. The elastin concentration was similar in both territories, but not its morphology according to its spatial distribution. We have observed a relationship between the elastin structural organisation from the media of arteries and of the internal elastic lamina in these territories and the variation of reactivity to the smooth muscle alpha-actin as a marker of the phenotypic state. Our results confirm the hypothesis that elastin, besides intervening in the architecture of the arterial wall, is a factor implicated in the phenotypic variability of the smooth muscle cells and in the development and evolution of the intimal thickenings in human atherosclerosis.

Adult↗
PubMed2000

Diagnosis of pneumonia and monitoring of infection eradication.

Pneumonia can be classified as community-acquired (CAP) or hospital-acquired (nosocomial). Both are frequent infections that demand a great amount of medical resources. The diagnosis of CAP is based on clinical signs and the presence of a pulmonary infiltrate visible on chest radiograph. For practical purposes, CAP has been classified as typical, with an acute onset in which the most representative microorganism is Streptococccus pneumoniae, and atypical, with a subacute onset (Mycoplasma pneumoniae). Nevertheless, so far no studies have clearly demonstrated the utility of this classification in predicting the aetiology. Guidelines on CAP recommend associating the aetiology of CAP with comorbidity, age and severity. The microbiological diagnosis relies mainly on Gram stain and sputum culture, but this technique has disadvantages such as frequent contamination of the sample with oropharyngeal commensal flora, frequent sterile cultures associated with previous antibiotic treatment, and the fact that approximately 40% of patients are not able to expectorate. Other diagnostic techniques such as blood cultures, serological tests and fibreoptic bronchoscopy must be reserved for patients who are hospitalised, especially if they need admission to an intensive care unit. Compared with CAP, nosocomial pneumonia has major diagnostic problems due to the presence of other diseases able to mimic pneumonia and frequent bacterial colonisation of the lower respiratory tract. Most of the diagnostic techniques produce a high percentage of false-negative and false-positive results. This is especially true for ventilator-associated pneumonia. There is controversy over using a comprehensive aetiological work-up based on bronchoscopic techniques or only on quantitative culture of endotracheal aspiration. By contrast, there is consensus about the importance of the adequacy of empirical antibiotic treatment, since mortality rates are higher in patients who are inadequately treated. Once treatment of pneumonia has begun, it must be maintained for 48 to 72 hours because this is the minimum time to evaluate a clinical response. Antibacterial agents have to be adjusted according to microbiological findings. In nonresponding patients, pneumonia-related complications and the presence of multiresistant micro-organisms or non-covered pathogens must be ruled out.

Anti-Bacterial Agents↗
PubMed2000

Detection of telomerase activity in human carcinomas using a trap-ELISA method: correlation with hTR and hTERT expression.

We have evaluated telomerase activity in a tumour population of 65 human cancers by using a TRAP-based method, in which detection is performed by an enzyme immunoassay (ELISA). We have corroborated that sensitivity and specificity of this new procedure can be considered similar to that of classical TRAP method, having the advantage of a rapid and reproducible analysis of large pools of samples. Thus, telomerase activity was detected in 83% of the tumours included in our population. Moreover, we found a significant association between enzyme activity and both hTR and hTERT expression (P=0.004 and P=0.04, respectively).

DNA-Binding Proteins↗
PubMed2000

Myeloid mixed chimerism is associated with relapse in bcr-abl positive patients after unmanipulated allogeneic bone marrow transplantation for chronic myelogenous leukemia.

BACKGROUND AND OBJECTIVE: Although bcr-abl polymerase chain reaction (PCR) positivity after bone marrow transplantation (BMT) for chronic myelogenous leukemia (CML) is significantly related to relapse, the predictive value of the assay is not very high and therefore most investigators consider that qualitative RT-PCR data alone are too imprecise to enable clinical decisions to be taken in individual cases. To define the clinical outcome of bcr-abl positive patients after unmanipulated BMT better, we sought the origin of hematopoiesis and traced its evolution over time. DESIGN AND METHODS: Forty-nine patients received allogeneic BMT for CML (39 in chronic phase and 10 in accelerated phase/blast crisis). Median follow-up was 61 months (range 4-92). mRNA and DNA were used to assess bcr-abl and chimerism status respectively. Quantitative VNTR-PCR on total cells and lymphoid or myeloid population allowed us to assign and measure the origin of hematopoiesis. RESULTS: Both bcr-abl positivity and the presence of mixed chimerism (MC) were significantly associated with relapse (p = 0.0009 and p < 0.0001 respectively). Relapse was observed in one of 39 patients with complete donor chimerism and in 6 of 9 patients with MC. These six cases showed increasing levels of host hemopoiesis and bcr-abl positivity in the CD15-positive population prior to relapse. The other three cases had decreasing or stable low-level MC which was restricted to the T-cells as well as bcr-abl negativity. INTERPRETATION AND CONCLUSIONS: Whereas the simple detection of bcr-abl fails to identify patients who will relapse with certainty, the assessment of MC by VNTR-PCR does identify patients headed to relapse. Confirmation of myeloid involvement and increasing levels over time further elucidates the clinical outcome of bcr-abl positive patients after BMT.

Adolescent↗
PubMed2000

Unrelated donor bone marrow transplantation as treatment for chronic myeloid leukemia: the Spanish experience. The Chronic Myeloid Leukemia Subcommittee of the GETH. Grupo Español de Trasplante Hemopoyético.

BACKGROUND AND OBJECTIVE: To analyze the results of unrelated bone marrow transplantation (UDBMT) as treatment for chronic myeloid leukemia (CML) in Spain. DESIGN AND METHODS: Eighty-seven consecutive UDBMT performed in 9 centers between October 1989 and February 1998 were evaluated. This represents more than 95% of UDBMT for CML performed in adult transplant centers in Spain during this period. The patients' median age was 31.5 years (range, 12-49). The median interval from CML diagnosis to UDBMT was 30 months (range, 3-160). Seventy-nine percent of transplants were performed during the first chronic phase (1CP). RESULTS: Actuarial probability of survival and disease-free survival at 4 years for the whole series was 24% (95% confidence interval [CI]: 14%-34%) and 20% (CI: 10%-30%), respectively. The cumulative incidence of relapse and transplant-related mortality (TRM) was 7% (CI: 4%-10%) and 71% (CI: 60%-82%), respectively. The main causes of death were graft failure (n=7), infection (n=23), and graft-versus-host disease (GvHD) (n=25). The actuarial probability of acute GvHD grade II-IV and grade III-IV was 56% (CI:46%-66%) and 36% (CI: 26%-36%), respectively. The cumulative incidence of extensive chronic GvHD was 18% (CI: 9%-27%). Univariate analyses showed that the pre-transplant factor with the highest influence on survival was disease status at transplant (30% in 1CP vs. 0% in advanced phases; p=0.0001). Other pre-transplant factors influencing survival among patients in 1CP were: patient's age (older than 30 years 11% vs. 48%), interval diagnosis-transplantation (longer than 2 years 17% vs. 55%), donor type (HLA, B, DRB1 identical 32% vs. 25%), CMV serologic status (donor and recipient negative 63% vs. 24%), year of transplantation (before 1995 19% vs. 40%), and conditioning regimen (cyclophosphamide plus total body radiation 40% vs. 16%). The main risk factors had a cumulative effect on survival. Thus, probability of survival ranged from 66% (CI: 39%-93%) in patients in 1CP, under 40 years of age, transplanted from an HLA, A, B, DRB1 identical donor during the first two years after diagnosis, to 0% in those with three or more risk factors. INTERPRETATION AND CONCLUSIONS: This experience shows that UDBMT used to have a high TRM that has progressively decreased along the years. At the present time, the results are encouraging, particularly when UDBMT is performed under favorable conditions.

Actuarial Analysis↗
PubMed2000

Fibrinogen Caracas V, an abnormal fibrinogen with an Aalpha 532 Ser-->Cys substitution associated with thrombosis.

A new dysfibrinogenemia associated with thrombophilia has been identified in a Venezuelan kindred. Thrombin and Reptilase times were prolonged and the accelerating capacity of the patient's fibrin on the t-PA-induced plasminogen activation was decreased. In addition the affinity of fibrinogen for plasminogen was diminished. Permeability and electron microscopy studies revealed that the abnormal clot was made up of thin and densely packed fibres giving rise to a reduced fibrin gel porosity. This was confirmed by turbidity studies showing a decreased fibre mass/length ratio. Affected members were heterozygous for an Aalpha 532 Ser-->Cys mutation as demonstrated by genetic analyses. This abnormal fibrinogen has been designated as Fibrinogen Caracas V. The family study showed a convincing association between the mutation and thrombotic manifestations. The thrombotic tendency may be ascribed to lack of accelerating capacity of fibrin to induce fibrinolysis caused by an abnormal clot structure with thin fibres and reduced porosity.

Adolescent↗
PubMed2000

Molecular basis for therapeutic decisions in chronic myeloid leukemia patients after allogeneic bone marrow transplantation.

BACKGROUND AND OBJECTIVES: Recent progress in the development of diagnostic techniques has greatly facilitated the monitoring of minimal residual disease (MRD) in patients with chronic myeloid leukemia (CML) after allogeneic bone marrow transplantation (BMT), the only curative treatment for this disease. The presence of the P210(bcr-abl) rearrangement in CML cells has allowed highly sensitive detection of MRD by polymerase chain reaction (PCR). However, complete eradication of the leukemic clone may not be a necessary prerequisite for long-term remission or cure. This observation limits the value of qualitative PCR analysis for prediction of progressive disease and highlights the need to monitor the proliferative activity of the malignant clone in order to permit timely detection of impending relapse and, thus, early therapy. This article discusses the applicability of several molecular methods to the monitoring of treatment efficacy and early assessment of clonal expansion in patients with CML after BMT. It also presents guidelines for clinical use of PCR analyses and the most effective approaches to treat relapsed patients. INFORMATION SOURCES: The authors have been working in this field, both experimentally and at a clinical level, contributing original papers to peer-reviewed journals. The material examined in this review includes articles published in journals covered by MedLine and reviews from journals with a high impact factor. STATE OF THE ART AND PERSPECTIVES: In view of the very limited value of qualitative PCR in detecting CML patients destined to relapse after BMT, several investigators have developed molecular assays that enable the kinetics of MRD to be monitored over time (e.g. quantitative PCR for P210(bcr-abl), PCR analysis of whole blood/lineage-specific chimerism and qualitative PCR for P190(bcr-abl)). These molecular strategies closely trace the kinetics of leukemic regrowth. Disease evolution in relapsed patients is consistently characterized by the sequential detection of increasing P210(bcr-abl) transcript levels, increasing myeloid mixed chimerism and finally, P190(bcr-abl) positivity preceding cytogenetic relapse. A 10-fold or greater increase in the expression of P210(bcr-abl) confirmed by a minimum of three independent quantitative PCR analyses and/or a progressive increase in the percentage of host myeloid cells in three consecutive chimerism analyses and/or P190(bcr-abl) mRNA detection must be regarded as an indication of incipient disease progression and should provide a rationale for initiation of treatment. There are various approaches to the management of the patient who relapses. The first step, if possible, is to reduce or terminate immune suppression. If the patient is not receiving this therapy, he or she can be treated with hydroxyurea or interferon or can be offered a second transplant. However, infusion to the patient of lymphoid cells (DLI) collected from the original donor has the capacity to restore complete remission in 70-80% of cases. Currently, several strategies are being used to minimize the severity of graft-versus-host disease after DLI (optimization of transfused lymphocyte doses, modification of the transfused lymphocyte subsets, administration of lymphocytes in escalating doses or lymphocyte transfection with a suicide gene), to reduce the incidence of marrow aplasia (stem cell support) and to increase the rate of complete responses (cytokines associated with DLI, leukemia-reactive cytotoxic lymphocytes, tyrosine kinase inhibitors or pre-emptive DLI).

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2000

Correlation between the internalization theme of racial identity attitude survey-B and systolic blood pressure.

OBJECTIVES: This brief report describes our first attempts at defining relationships between racial identity attitudes as measured by the Racial Identity Attitudes Survey-B (RIAS-B) and cardiovascular responses during the presentation of stressful stimuli. DESIGN: We manipulated verbal tasks to study reactivity and derived correlation coefficients to define relationships between racial identity attitudes and cardiovascular responses. METHOD: The participants (N = 17) were African-American students participating in a summer program to enhance minority careers (N = 15) or enrolled in introductory psychology. All students held a dominant Internalization theme for racial identity as assessed by the RIAS-B. After the initial baseline, the participants responded to three verbal tasks incorporating the description of a frustrating event with racial overtones (HIAFF), a description of the furniture in their house (LOAFF) and serial digit multiplication (MATH). RESULTS: The data indicate significant correlations between the Internalization score on the RIAS-B and the systolic blood pressure (SBP) for tasks as grouped by content (HIAFF r = .60; MATH r = .55) or by sequence (TASK1 r = .53, TASK2 r = .50). There were no significant correlations between Internalization score and pulse rate or diastolic blood pressure (DBP). Students had a high incidence of a positive family history for cardiovascular diseases (70%). CONCLUSIONS: The data suggest that as identity accumulation increases, so does reactivity. Internalization and the related self-esteem that this theme might engender does not attenuate the cardiovascular stress response in African-American college students with a prevalence of a positive family history for cardiovascular disease.

Adolescent↗
PubMed1999

[The monitoring of BCR-ABL mRNA by reverse transcription PCR in patients undergoing allogeneic bone marrow transplantation for acute lymphoblastic leukemia with a positive Philadelphia chromosome].

BACKGROUND: Allogeneic bone marrow transplantation (BMT) has been performed as one mode of cure-oriented therapy for Philadelphia chromosome-positive acute lymphoblastic leukemia (ALL-Ph' positive). However, the clinical significance of the residual BCR-ABL-positive clones after BMT is still controversial. PATIENTS AND METHODS: The BCR-ABL gene (p210 and p190) was prospectively studied by nested RT-PCR in 8 ALL-Ph' positive patients undergoing BMT. RESULTS: All patients received BMT at the time of clinical remission (CR). However, minimal residual disease (MRD) was detected in 7 of them. MRD detected just before BMT seems to be eradicated by BMT protocol. Four patients remained in CR and did not show BCR-ABL transcripts. Other 4 patients, relapsed, demonstrating MRD, which preceded recurrence by a median time of 6 weeks. Three relapsed patients showed p190 transcript and only one, p210 type. CONCLUSIONS: The RT-PCR assay appears to be a useful test for predicting at high risk of relapse after BMT and may identify patients who might benefit from therapeutic interventions. The finding that the expression of p190 BCR-ABL may carry an especially high risk of relapse suggests a different clinical and biologic behaviour between p190 and p210 BCR-ABL.

Adult↗
PubMed1999

Supine body position as a risk factor for nosocomial pneumonia in mechanically ventilated patients: a randomised trial.

BACKGROUND: Risk factors for nosocomial pneumonia, such as gastro-oesophageal reflux and subsequent aspiration, can be reduced by semirecumbent body position in intensive-care patients. The objective of this study was to assess whether the incidence of nosocomial pneumonia can also be reduced by this measure. METHODS: This trial was stopped after the planned interim analysis. 86 intubated and mechanically ventilated patients of one medical and one respiratory intensive-care unit at a tertiary-care university hospital were randomly assigned to semirecumbent (n=39) or supine (n=47) body position. The frequency of clinically suspected and microbiologically confirmed nosocomial pneumonia (clinical plus quantitative bacteriological criteria) was assessed in both groups. Body position was analysed together with known risk factors for nosocomial pneumonia. FINDINGS: The frequency of clinically suspected nosocomial pneumonia was lower in the semirecumbent group than in the supine group (three of 39 [8%] vs 16 of 47 [34%]; 95% CI for difference 10.0-42.0, p=0.003). This was also true for microbiologically confirmed pneumonia (semirecumbent 2/39 [5%] vs supine 11/47 [23%]; 4.2-31.8, p=0.018). Supine body position (odds ratio 6.8 [1.7-26.7], p=0.006) and enteral nutrition (5.7 [1.5-22.8], p=0.013) were independent risk factors for nosocomial pneumonia and the frequency was highest for patients receiving enteral nutrition in the supine body position (14/28, 50%). Mechanical ventilation for 7 days or more (10.9 [3.0-40.4], p=0.001) and a Glasgow coma scale score of less than 9 were additional risk factors. INTERPRETATION: The semirecumbent body position reduces frequency and risk of nosocomial pneumonia, especially in patients who receive enteral nutrition. The risk of nosocomial pneumonia is increased by long-duration mechanical ventilation and decreased consciousness.

Aged↗
PubMed1999

Effect of nasogastric tube size on gastroesophageal reflux and microaspiration in intubated patients.

BACKGROUND: Little evidence exists to support the theory that small-bore nasogastric tubes prevent gastroesophageal reflux and microaspiration in intubated patients. OBJECTIVE: To determine whether gastroesophageal reflux and microaspiration in intubated patients can be reduced by the use of a small-bore nasogastric tube. DESIGN: Randomized, two-period crossover trial. SETTING: Respiratory intensive care unit of a university hospital. PATIENTS: 17 patients intubated for more than 72 hours. INTERVENTIONS: Radioactive technetium colloid was instilled in each patient's stomach. Patients were studied with two nasogastric tubes (one tube with a 6.0-mm external bore and one tube with a 2.85-mm external bore) in randomized order; measurements of radioactive counts with the alternate size of nasogastric tube were repeated 72 hours after original measurements were taken. Sequential samples of serum, gastric juice, and pharyngeal and tracheal secretions were obtained. MEASUREMENTS: Comparison of the time course of radioactive counting in all samples (obtained during the use of each nasogastric tube size in each patient). RESULTS: The mean radioactive count of pharyngeal aspirates (P = 0.004) was greater than the baseline count at all time points, as was the cumulative radioactive count of pharyngeal aspirates 17 hours after the first dose of technetium colloid was administered (P = 0.001); however, the count of tracheal aspirates was never greater than the count at baseline. No differences were found between tube types when the time course and cumulative counts of pharyngeal and tracheal samples were compared. CONCLUSION: Small-bore nasogastric tubes in intubated patients do not reduce gastroesophageal reflux or microaspiration.

Cross-Over Studies↗
PubMed1999

[Prognostic value of heterozygosity loss in chromosome 3p in non-microcytic bronchogenic carcinoma].

BACKGROUND: Recent advances on carcinogenesis have led to the recognition of different patterns of behaviour of non-small cell lung cancers apart from those guided by the TNM staging system and the histologic subtype. The frequent genetic loss on chromosome 3p in all kinds of lung carcinoma leads to the suspect of the presence of a tumor suppressor gene located in that place. The aim of this work was to compare the different clinical features and evolution after treatment of the patients with non small cell lung carcinoma with and without loss of heterozygosity (LOH) on 3p. PATIENTS AND METHOD: Forty-five operated on non-small cell lung cancer patients were evaluated. The mean age was 64.4 years and all the patients were male. Seven patients had been previously treated for another epithelial neoplasm. 82.2% of the patients were heavy tobacco smokers. Most of the tumors (62.2%) were squamous cell carcinomas. Samples of tumoral and non tumoral lung tissue were immediately frozen after surgery. DNA from the tissue was extracted; then PCR amplification of microsatellites in regions 3p14 and 3p21 was performed. To determine the LOH in the regions analyzed a polyacrylamide gel electrophoresis was performed. RESULTS: Twenty-five percent of the informative samples for 3p14 and 21.9% for 3p21 showed LOH. There was an statistical relationship between the LOH on 3p14 and the history of tobacco smoking and the adenocarcinoma histologic subtype (p < 0.05). There was a higher number of relapses and a shorter disease-free interval in those patients harboring 3p21 LOH. CONCLUSIONS: LOH on 3p can be detected in non-small cell lung carcinoma. Patients with loss of heterozygosity on 3p21 have a worse evolution after a curative intended surgical resection.

Adult↗