Biomedical subjects

T Guerrero

Publications and source records attributed to T Guerrero.

8 recordsLinked to original sources

PubMed2004

Acquiring 4D thoracic CT scans using a multislice helical method.

Respiratory motion degrades anatomic position reproducibility during imaging, necessitates larger margins during radiotherapy planning and causes errors during radiation delivery. Computed tomography (CT) scans acquired synchronously with the respiratory signal can be used to reconstruct 4D CT scans, which can be employed for 4D treatment planning to explicitly account for respiratory motion. The aim of this research was to develop, test and clinically implement a method to acquire 4D thoracic CT scans using a multislice helical method. A commercial position-monitoring system used for respiratory-gated radiotherapy was interfaced with a third generation multislice scanner. 4D cardiac reconstruction methods were modified to allow 4D thoracic CT acquisition. The technique was tested on a phantom under different conditions: stationary, periodic motion and non-periodic motion. 4D CT was also implemented for a lung cancer patient with audio-visual breathing coaching. For all cases, 4D CT images were successfully acquired from eight discrete breathing phases, however, some limitations of the system in terms of respiration reproducibility and breathing period relative to scanner settings were evident. Lung mass for the 4D CT patient scan was reproducible to within 2.1% over the eight phases, though the lung volume changed by 20% between end inspiration and end expiration (870 cm3). 4D CT can be used for 4D radiotherapy, respiration-gated radiotherapy, 'slow' CT acquisition and tumour motion studies.

Humans↗

PubMed2001

Factors associated with relapse after ambulatory treatment of acute exacerbations of chronic bronchitis. DAFNE Study Group.

This study aimed to identify the risk factors for relapse after ambulatory treatment of acute exacerbations of chronic bronchitis (AECB) that can easily be used in a primary care setting. Data were prospectively collected on 2,414 ambulatory patients with AECB from 268 general practices located throughout Spain. A multivariate model to identify risk factors independently associated with failures was developed and validated from the information recorded at the inclusion visit and at 30-days follow-up visit. A total of 507 patients relapsed (21%); of these, 84 required admission (16.5%). The multivariate model for prediction of the risk of relapse included 2,414 cases: 1,689 for the developmental sample and 725 in the validation sample. The model obtained contained three readily-obtainable variables: ischaemic heart disease (odds ratio (OR)=1.63; 95% confidence interval (CI)=1.07-2.47), degree of dyspnoea (OR = 1.31; 1.14-1.50) and number of visits to the general practitioner the previous year (OR = 1.07; 1.04-1.10). The model calibrated well in developmental and validation samples (goodness-of-fit tests: p = 0.295 and p = 0.637, respectively). Severity of the exacerbation was not associated with increased risk of relapse in either univariate or multivariate analysis. The present results suggest that baseline characteristics of the patients such as degree of dyspnoea, coexisting ischaemic heart disease and number of previous visits to the general practitioner for respiratory problems are strongly associated with increased risk of relapse after ambulatory treatment of acute exacerbations of chronic bronchitis. In contrast, exacerbation severity was not associated with clinical failure. Guidelines for management of acute exacerbations of chronic bronchitis should consider such risk factors and advocate intensive broad spectrum treatment and closer follow-up of patients exhibiting them.

Aged↗

PubMed2001

Criteria used by general practitioners in prescribing prokinetic or antisecretory drugs in patients with functional dyspepsia.

OBJECTIVE: To analyze the clinical factors considered by general practitioners for the prescription of prokinetic or antisecretory drugs in patients with functional dyspepsia (FD), and to assess therapeutic outcomes and factors predicting effectiveness. DESIGN: Multicentric, prospective and observational study. PATIENTS: 1,021 patients with FD were included. One hundred and thirty-two (132) were excluded from the analysis because they were taking ASA or NSAID. Patients were classified according to their predominant symptoms as reflux, ulcer, dysmotility or non-specific. At the physician discretion, treatment with alkali drugs was prescribed to 38 patients, prokinetic drugs to 574, antisecretory drugs to 123 and a combined therapy to 154. One month later, patient self-perception of symptomatic improvement was evaluated in patients treated with prokinetic drugs and antisecretory drugs. RESULTS: 85% of the patients reported symptomatic improvement after one month of treatment. Patients with non-specific FD had lower improvement rates regardless of the drug used (prokinetic or antisecretory) (77%) compared to all the other types (p = 0.03). Prescription of prokinetics was associated to female gender (OR: 0.43; 95% CI: 0.28-0.66) and early satiety (OR: 2.5; 95% CI: 1.6-4.1). A longer symptomatic evolution (OR 0.92: 95% CI: 0.88-0.97) was the only independent predictive factor of a poor response to prokinetic drugs. CONCLUSIONS: Among patients with FD attended by general practitioners, female gender and early satiety symptom were associated to the prescription of prokinetic drugs. Early symptomatic effectiveness rates for prokinetic or antisecretory drugs alike were high (85%). Patients with non-specific dyspepsia or long symptomatic evolution showed less favorable symptomatic response to prokinetic drugs.

Adolescent↗

PubMed2000

[Development and results of a screening program for COPD in primary care. The PADOC Project(Program for the Increase in the Diagnosis of COPD in Primary Care].

Several studies have shown that up to 75% of patients with chronic obstructive pulmonary disease (COPD) remain undiagnosed. Early diagnosis of such individuals will allow appropriate preventive and therapeutic measures to be prescribed. The PADOC project aimed to determine the efficacy of a COPD screening program for Spanish primary care settings. The participating primary care physicians were required to administer a spirometric test (forced expiratory volume) to all individuals who had not previously been given a diagnosis of COPD, who visited the clinic for any reason over a period of three months and who met the following enrollment criteria: a) age over 35 years and b) smoker of more than 10 cigarettes per day or ex-smoker of more than 10 packs per year. Individuals meeting the criteria for suspicion of COPD (FEV1 < 90% of predicted and FEV1/FVC < 70%) were referred to a pneumologist for confirmation of the diagnosis. One hundred ninety-four primary care physicians participated, administering 3,209 valid spirometric tests. The physicians identified 723 likely cases of COPD (22.5%). Pneumologists examined 278 patients (38.4% of the likely cases) and the final diagnosis was COPD in 153 of the 278 (55%) and asthma in 28 (10%). Therefore, 4.3% of all patients given spirometric tests received a diagnosis of COPD and 0.8% received a diagnosis of asthma. Agreement between spirometric measurements taken by the primary care physicians and those taken by pneumologists was low for FVC and FVC (%) (intra-class correlation coefficient ICC = 0.38 and 0.45, respectively) but good for FEV1 and FEV1 (%) (ICC = 0.78 and 0.67, respectively). We conclude that primary care screening for COPD is possible and would allow us to detect up to 22% of possible cases. Patient flow from one level of clinical care to another should be improved, given that most of the possible cases detected (61.6%) were not seen by the referral pneumologist. Agreement between spirometric measurements taken by primary care physicians and pneumologists was low for FVC but good for FEV1.

Adult↗

PubMed2000

Factors associated with increased risk of exacerbation and hospital admission in a cohort of ambulatory COPD patients: a multiple logistic regression analysis. The EOLO Study Group.

BACKGROUND AND OBJECTIVE: The aim of this study was to develop and validate two models to estimate the probabilities of frequent exacerbations (more than 1 per year) and admissions for chronic obstructive pulmonary disease (COPD) that can be used in a primary care setting. METHODS: Information was obtained in a cross-sectional observational study on ambulatory COPD patients performed in 201 general practices located throughout Spain. The model for admissions included 713 cases, 499 for the developmental sample and 214 in the validation sample; the model for frequent exacerbations included 896 patients, 627 in the developmental sample and 269 in the validation model. Candidate variables to be included in both models were: age, sex, body mass index (BMI), FEV(1) as percent predicted [FEV(1 )(% pred.)], active smoking, chronic mucus hypersecretion (CMH) and significant comorbidity. RESULTS: The admission model contained 2 readily obtainable variables: comorbidity (OR = 1.97; CI 95% = 1. 24-3.14) and FEV(1)(% pred.) (OR = 0.72; 0.58-0.88, for every 10 units), and well calibrated in developmental and validation samples (goodness-of-fit tests: p = 0.989 and p = 0.720, respectively). The model for frequent exacerbations included 3 variables: age (OR = 1. 21; 1.01-1.44; for every 10 years of increasing age), FEV(1 )(% pred. ) (OR = 0.82; 0.70-0.96, for every 10 units) and CMH (OR = 1.54; 1. 11-2.14) and also well calibrated (p = 0.411 and p = 0.340 in the developmental and validation samples, respectively). CONCLUSIONS: Our results suggest that FEV(1) impairment explains part of the risk of frequent exacerbations and hospital admissions. Furthermore, CMH and increasing age are significantly associated with the risk of frequent exacerbations, but severity of exacerbations provoking hospital admissions is associated with the presence of significant comorbidity. These important and easily measurable variables contain valuable information for optimal management of ambulatory patients with COPD.

Age Factors↗

PubMed2000

Detection of Fasciola hepatica infection in a community located in the Ecuadorian Andes.

The presence of fascioliasis was assessed in four Andean communities using an enzyme-linked immunosorbent assay (ELISA) test to measure antibodies against Fasciola hepatica excretion-secretion antigens. Six percent (9 out of 150) of the individuals in one community were ELISA-positive for these antibodies. Fecal samples from two of the ELISA-positive individuals contained F. hepatica ova. All of the ELISA-positive cases, except for one, were children within the ages of 9 to 12 years.

Adult↗

PubMed1999

[Treatment of chronic bronchitis and chronic pulmonary obstructive disease in primary care].

In spite of the recent publication of various guidelines for the treatment of chronic bronchitis and chronic obstructive pulmonary disease (COPD), no studies have investigated whether or not they are being implemented by caregivers. Our aim was to determine what treatment protocols for patients with chronic bronchitis and COPD are most commonly applied by general practitioners in Spain and to identify factors associated with the prescription of certain drugs. A standardized questionnaire was administered to 268 general practitioners working in the 17 autonomous communities of Spain. The stratified sample of respondents was selected to reflect the population of each community. Valid information on 2,414 patients was collected. Men accounted for 74% of the patients. Mean age was 67 years (SD = 10). Lung function data were available for 1,130 (47%) and mean FEV1 was 1,523 ml (56% of the theoretical reference value). Patients without lung function data in spite of having signs of severe symptoms had suffered more acute exacerbations and generated more visits to the emergency room and to their primary care doctors in the preceding year than had patients who had undergone lung function testing (p < 0.03; p < 0.001; p < 0.003, respectively). The treatments most often prescribed were short-acting inhaled beta-2 agonists (56%), inhaled corticoids (47%), theophylline-containing drugs (43%), and long-lasting beta-2 agonists (41%). Patients who had not undergone function tests received more mucolytics (47% versus 27%, p < 0.001) and fewer anticholinergics (20% versus 35%, p < 0.001). The factor most highly associated with prescription of all drugs was severity of disease measured by dyspnea. Treatment protocols for chronic bronchitis and COPD in general practice in many aspects show differences from current guidelines. Noteworthy is the extensive use of inhaled corticoid therapy and long-lasting beta-2 adrenergic agonists and the infrequent prescription of anticholinergics. The lack of lung function data is associated with poor pharmacologic management of disease and higher rates of morbidity.

Aged↗

PubMed1992

Role of gelsolin interaction with actin in regulation and creation of actin nuclei in chemotactic peptide activated polymorphonuclear neutrophils.

In vitro Ca++ activates gelsolin to sever F-actin and form a gelsolin-actin (GA) complex at the+end of F-actin that is not dissociated by ethylene glycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid (EGTA) but is separated by EGTA+PIP/PIP2. The gelsolin blocks the+end on the actin filament, but the-end of the filament can still initiate actin polymerization. In thrombin activated platelets, evidence suggests that severing of F-actin by gelsolin increases GA complex, creates one-end actin nucleus and one cryptic+end actin nucleus per cut, and then dissociates to yield free+ends to nucleate rapid actin assembly. We examined the role of F-actin severing in creation and regulation of nuclei and polymerization in polymorphonuclear neutrophils (PMNs). At 2-s intervals after formyl peptide (FMLP) activation of endotoxin free (ETF) PMNs, change in GA complex was correlated with change in+end actin nuclei,-end actin nuclei, and F-actin content. GA complex was quantitated by electrophoretograms of proteins absorbed by antigelsolin from cells lysed in 10 mM EGTA,+end actin nuclei as cytochalasin (CD) sensitive and-end actin nuclei as CD insensitive increases in G-pyrenyl actin polymerization rates induced by the same PMNs, and F-actin content by NBDphallacidin binding to fixed cells. Thirty three percent of gelsolin was in GA complex in basal ETF PMNs; from 2-6 s, GA complexes dissociate (low = 15% at 10 s) and sequentially+end nuclei and F-actin content and then-end nuclei increase to a maximum at 10 s. At > s GA complex increase toward basal and + end nuclei and F-actin content returned toward basal. These kinetic data show gelsolin regulates availability of + end nuclei and actin polymerization in FMLP. However, absence of an initial increase in GA complex or - end nucleating activity shows FMLP activation does not cause gelsolin to sever F- or to bind G-actin to create cryptic + end nuclei in PMNs; the results suggest the + nucleus formation is gelsolin independent.

Actins↗