Search PubMed⌕ Search

Biomedical subjects

A Torres

Publications and source records attributed to A Torres.

At least 37 records · Page 2Linked to original sources
PubMed2002

Biofilm formation in endotracheal tubes. Association between pneumonia and the persistence of pathogens.

Nosocomial pneumonia is still a common problem, especially in intubated and mechanically ventilated patients. The endotracheal tube contributes substantially to the pathogenesis of pneumonia in these patients, because it facilitates microaspiration and impairs host defences. Common nosocomial pathogens like Pseudomonas aeruginosa are known to produce exopolysaccharide and generate the complex biofilm structure, which allows adhesion to abiotic surfaces and protection against antibiotic action. Multiple studies have identified bacterial biofilm on the inner lumen of endotracheal tubes, which represents a permanent source of infectious material. Endotracheal tubes, removed from patients with ventilator-associated pneumonia are covered more frequently with biofilm than those of uninfected controls. It remains unclear whether this represents a source of infection or contamination. Bacterial biofilm, however, may play an important role in recurrent pulmonary infections of the intubated and mechanically ventilated patient.

Biofilms↗
PubMed2001

Different stop codon usage in two pseudohypotrich ciliates.

Based on rRNA phylogeny, morphologic and morphogenetic characters, two major groups of hypotrich ciliates can be distinguished: euhypotrichs and pseudohypotrichs. Through the sequencing of actin genes, we show here that, interestingly, the pseudohypotrichs Dyophrys sp. and Euplotes vannus have a different stop codon usage. In fact, the stop codon usage of the former species resembles that of euhypotrichs. This unexpected result is used to discuss the origin and acquisition of genetic code deviations in ciliates.

Actins↗
PubMed2001

Bronchial inflammation and colonization in patients with clinically stable bronchiectasis.

To evaluate the bronchial inflammatory response and its relationship to bacterial colonization in bronchiectasis, we performed a bronchoalveolar lavage (BAL) in 49 patients in stable clinical condition and in nine control subjects. BAL was processed for differential cell count, quantitative bacteriologic cultures, and measurement of inflammatory mediators. An increase was observed in the percentage of neutrophils (37 [0 to 98]) (median[range]) versus 1[0 to 4]%, p = 0.01), in the concentration of elastase (90.5 [8 to 2,930] versus 34 [9 to 44], p = 0.03), myeloperoxidase (9.1 [0 to 376] versus 0.3 [0.1 to 1.4], p = 0.01), and in the levels of TNF-alpha (4 [0 to 186] versus 0 [0 to 7], p = 0.03), IL-8 (195 [0 to 5,520] versus 3 [0 to 31], p = 0.001), and IL-6 (6 [0 to 115] versus 0 [0 to 3], p = 0.001) in patients with bronchiectasis compared with control subjects. Noncolonized patients showed a more intense bronchial inflammatory reaction than did control subjects. This inflammatory reaction was exaggerated in patients colonized by microorganisms with potential pathogenicity (MPP), with a clear relationship with the bronchial bacterial load. Patients with bronchiectasis showed a slight systemic inflammatory response, with poor correlations between systemic and bronchial inflammatory mediators, suggesting that the inflammatory process was mostly compartmentalized. We conclude that patients with bronchiectasis in a stable clinical condition present an active neutrophilic inflammation in the airways that is exaggerated by the presence of MPP, and the higher the bacterial load the more intense the inflammation.

Bacterial Infections↗
PubMed2001

Characterization of the Mycobacterium tuberculosis region containing the mpt83 and mpt70 genes.

Like the products of the genes mpt83 and mpt70, the putative protein encoded by the gene located between these genes was undetectable in Mycobacterium tuberculosis with an antiserum raised against the recombinant protein. The protein showed 100% homology with M. tuberculosis Rv2874 and similarities with CcdA and DipZ proteins involved in cytochrome-c biogenesis in bacteria. Expression analysis by RT-PCR and transcriptional fusions of Rv2874 and their neighbor genes Rv2871, Rv2872, mpt83 and mpt70 with lacZ suggest that these genes are part of an operon and their transcription is driven by promoter regions located 5' upstream of mpt83 and of Rv2874 genes.

Amino Acid Sequence↗
PubMed2001

Pulmonary infiltrates in HIV-infected patients in the highly active antiretroviral therapy era in Spain.

OBJECTIVE: To study the incidence, etiology, and outcome of pulmonary infiltrates (PIs) in HIV-infected patients and to evaluate the yield of diagnostic procedures. DESIGN: Prospective observational study of consecutive hospital admissions. SETTING: Tertiary hospital. PATIENTS: HIV-infected patients with new-onset radiologic PIs from April 1998 to March 1999. METHODS: The study protocol included chest radiography, blood and sputum cultures, serologic testing for "atypical" causes of pneumonia, testing for Legionella urinary antigen, testing for cytomegalovirus antigenemia, and bronchoscopy in case of diffuse or progressive PIs. RESULTS: One hundred two episodes in 92 patients were recorded. The incidence of PIs was 18 episodes per 100 hospital admission-years (95% confidence interval [CI]: 15-21). An etiologic diagnosis was achieved in 62 cases (61%). Bacterial pneumonia (BP), Pneumocystis carinii pneumonia (PCP), and mycobacteriosis were the main diagnoses. The incidences of BP and mycobacteriosis were not statistically different in highly active antiretroviral therapy (HAART) versus non-HAART patients. The incidence of PCP was lower in those receiving HAART (p =.011), however. Nine patients died (10%). Independent factors associated with higher mortality were mechanical ventilation (odds ratio [OR] = 83; CI: 4.2-1,682), age >50 years (OR = 23; CI: 2-283), and not having an etiologic diagnosis (OR = 22; CI: 1.6-293). CONCLUSIONS: Pulmonary infiltrates are still a frequent cause of hospital admission in the HAART era, and BP is the main etiology. There was no difference in the rate of BP and mycobacteriosis in HAART and non-HAART patients. Not having an etiologic diagnosis is an independent factor associated with mortality.

Adult↗
PubMed2001

Dorsal subthalamotomy for Parkinson's disease.

We report our experience of unilateral subthalamotomy in patients with Parkinson's disease (PD). Eleven patients were included in a pilot, open-labeled study to assess the effect of unilateral lesion of the subthalamic nucleus (STN) with a minimum of 12 months of follow-up. The guidelines of CAPIT (Core Assessment Program for Intracerebral Transplantation) were followed for recruitment into the study and follow-up assessment. Levodopa equivalents daily intake (mean 967 mg) were unchanged during the first 12 months in all but one patient who stopped medication. The sensorimotor region of the STN was defined by semimicrorecording and stimulation and a thermolytic lesion was placed accordingly. There was a significant reduction in both UPDRS parts II and III in the "off" state at 1-, 6-, and 12-month follow-up. This effect was maintained in four patients up to 24 months. The dyskinesia score did not change postoperatively. Lesion-induced dyskinesias were not a management problem except in one patient who developed a large infarction several days postsurgery. This initial study indicates that a lesion of the STN is not generally associated with hemiballismus in PD. Subthalamotomy may induce considerable motor benefit and could become another surgical option under specific circumstances.

Aged↗
PubMed2001

3p21, 5q21, and 9p21 allelic deletions are frequently found in normal bronchial cells adjacent to non-small-cell lung cancer, while they are unusual in patients with no evidence of malignancy.

Molecular cytogenetic and loss of heterozygosity (LOH) analyses of non-small-cell lung cancer (NSCLC) have shown frequent allelic deletions in a variety of chromosomes, such as 1p, 3p, 5q, 8p, 9p, 11p, 11q, and 17p. Allelic loss at 3p21, 9p21, and 5q21 has also been reported in premalignant epithelial lesions of the bronchus and in normal bronchial cells. These findings suggest that a tissue field of somatic genetic alterations precedes the histopathological phenotypic changes of carcinoma. LOH at chromosomal regions 3p21, 5q21, 9p21, and 17p (TP53) was looked for in the peritumoural normal bronchial cells from 30 archival surgically resected tumours. Microdissected normal bronchial cells from 20 benign cytological smears were also added to the study. Matched populations of lymphocytes, tumour cells, and normal bronchial cells adjacent to the tumour were microdissected from paraffin-embedded tissues, while matched populations of normal bronchial cells and inflammatory cells were microdissected from benign cytological smears (bronchial brushings). Polymerase chain reaction (PCR) amplification was performed utilizing the specific markers D5S346, D3S1300, D9S157, D9S171, and TP53. Within the NSCLC tumour cells, LOH was more frequently found at the 5q21 locus (72% of the informative cases), the 3p21 locus (47%), 9p21 (48%), and 17p (33%). Within the peritumoural normal bronchial cells, LOH at 5q21 was found in 37.5% of the cases, 22% showed LOH at 3p21, 27% at 9p21, and 13% at 17p (TP53). LOH was also detected in one case, in normal bronchial cells obtained from cytological smears at one locus (5q21). In conclusion, normal bronchial mucosa adjacent to NSCLC has frequent allelic losses at 3p21, 5q21, and 9p21, while LOH at these loci is unusual in normal bronchial cells obtained from cytological smears from patients with no evidence of malignancy. LOH at these loci may be present before the onset of the malignant growth. LOH studies may supplement the histopathological evaluation of bronchial cells to detect genotypic alterations in both cytological and biopsy specimens.

Adult↗
PubMed2001

Molecular analysis of Mycobacterium tuberculosis phosphate specific transport system in Mycobacterium smegmatis. Characterization of recombinant 38 kDa (PstS-1).

The functionality of the putative Mycobacterium tuberculosis phosphate transport operon was studied by operon- lacZ promoterless fusions in Mycobacterium smegmatis. The expression of the operon genes was evaluated in transformed M. smegmatis growing in medium with low and high phosphate concentration. Although the gene fusions expressed beta-galactosidase in medium with phosphate, a higher activity was detected in bacteria growing in medium with low phosphate. In contrast, alkaline phosphatase activity from M. smegmatis was detected only in bacteria growing in medium with low phosphate. The expression of the operon genes was driven by a promoter located 5' upstream from the start codon of the pstB gene. A second putative internal promoter 5' upstream of the pstS-1 gene was also detected. Furthermore, comparative analysis between the native and recombinant PstS-1 proteins showed that they were very similar. Like the native protein, the recombinant protein was also secreted to the culture medium as a glycosylated band. The results show that M. smegmatis recognized phosphate regulatory signals of the M. tuberculosis phosphate transport operon genes, and open the possibility to study gene phosphate regulation in mycobacteria.

Alkaline Phosphatase↗
PubMed2001

[Resection method and functional restoration in soft tissue sarcomas of the extremities].

In soft tissue sarcoma of the extremities wide tumor excision (R0) has become the most important factor for local control. The tactical and technical surgical parameters are defined, which allow for diminished complication rates during tumor biopsy and definite resection. Reconstructive plastic procedures play a key role in coverage of major defects and prevention of problems due to wound infection and irradiation. If localized within the periphery of limbs, the vast majority of cases will require sophisticated techniques to achieve limb salvage.

Adolescent↗
PubMed2001

Effects of bronchoalveolar lavage volume on arterial oxygenation in mechanically ventilated patients with pneumonia.

OBJECTIVE: To assess the effect of bronchoalveolar lavage (BAL) volume on arterial oxygenation in critically ill patients with pneumonia. DESIGN: Randomized clinical comparison. SETTING: Six-bed respiratory intensive care unit of a 850-bed tertiary care university hospital. PATIENTS: Thirty-seven intubated and mechanically ventilated patients with clinical suspicion of pneumonia. INTERVENTIONS: Bronchoscopically guided protected specimen brush (PSB) followed by either a "high volume" BAL (n = 16, protected catheter, mean volume: 131 +/- 14 ml) or a "low volume" BAL (n = 21, protected double-plugged catheter, 40 ml volume for all patients). MEASUREMENTS: Arterial oxygen tension/fractional inspired oxygen (PaO2/FIO2) and mean arterial pressure (MAP) before and up to 24 h after the intervention. Bacterial growth in quantitative cultures. Analysis of variance for repeated measurements with inter-subject factors. RESULTS: All patients showed a lower PaO2/FIO2 ratio and higher MAP after the diagnostic procedure, without differences between the study arms (p = 0.608 and p = 0.967, respectively). Patients with significant bacterial growth (p = 0.014) and patients without preemptive antibiotic (p = 0.042) therapy showed a more profound and longer decrease in arterial oxygenation after the diagnostic procedure. CONCLUSIONS: A decrease in the PaO2/FIO2 ratio was observed in all patients after a combined diagnostic procedure, independent of the BAL volume used. A significant bacterial burden recovered from the alveoli and no preemptive antibiotic therapy were associated with a larger and longer-lasting decrease in arterial oxygenation.

Analysis of Variance↗
PubMed2001

Turning scientific approaches into practical conservation actions: the case of Comunidad Indigena de Nuevo San Juan Parangaricutiro, Mexico.

Optimum natural resource management and biodiversity conservation are desirable goals. These, however, often exclude each other, since maximum economic benefits have promoted drastic reductions in biodiversity throughout the world. This dilemma confronts local stakeholders, who usually go for maximizing economic inputs, whereas other social (e.g., academic) sectors are favor conservation practices. In this paper we describe the way two scientific approaches--landscape and participatory research--were used to develop sound and durable land use scenarios. These two approaches included expert knowledge of both social and environmental conditions in indigenous communities. Our major emphasis was given to detect spatially explicit land use scenarios and capacity building in order to construct a decision support system operated by stakeholders of the Comunidad Indigena de Nuevo San Juan Parangaricutiro in Mexico. The system for decision-making was fed with data from inventories of both abiotic and biotic biodiversity components. All research, implementation, and monitoring activities were conducted in close collaboration with members of the indigenous community. As a major result we obtained a number of forest alternative uses that favor emerging markets and make this indigenous community less dependent on a single market. Furthermore, skilled members of the community are now running the automated system for decision-making. In conclusion, our results were better expressed as products with direct benefits in local livelihoods rather than pure academic outputs.

Conservation of Natural Resources↗
PubMed2001

Unusual characteristics of ciliate actins.

Actin is a cytoskeletal protein that is ubiquitous in eukaryotes, hence the corresponding genes and proteins have been isolated from numerous organisms as different as animals, plants, fungi and protozoa. Several atomic models are available for the monomeric as well as the filamentous form, and more than 70 proteins that bind actin and control filament dynamics have been isolated from diverse eukaryotes. Moreover, the function and dynamics of the actin cytoskeleton in several eukaryotic systems have been depicted in depth. Unlike other protozoa, such as amoeba, actin is not an abundant protein in ciliates, whose cytoskeleton is mainly composed of microtubular arrays. Ciliate actin has been studied in several species, and it was established early on that this ciliate protein is very different from that of other eukaryotes. Similarly, the actin-binding proteins studied in ciliates display great differences with those of other eukaryotes. Consequently, ciliate actin has been considered as "unconventional," and this review focuses on molecular data leading to this conclusion.

Actins↗