PubMed Health⌕ Search

Biomedical subjects

I Ferreira

Publications and source records attributed to I Ferreira.

At least 19 recordsLinked to original sources
PubMed2007

Congenital amegakaryocytic thrombocytopenia--report of a new c-mpl gene missense mutation.

A 44-month old girl with congenital amegakaryocytic thrombocytopenia, already with pancytopenia, underwent an unrelated allogeneic cord blood transplantation with recovery of normal blood cell counts. The patient was a compound heterozygote for two c-mpl missense mutations inherited from both parents, one of them, a G578A exon 4 mutation leading to a cysteine to tyrosine replacement of codon 193, previously unreported.

Child, Preschool↗
PubMed2006

[Present and future of the image guided radiotherapy (IGRT) and its applications in lung cancer treatment].

These last years, the new irradiation techniques as the conformal 3D radiotherapy and the IMRT are strongly correlated with the technological developments in radiotherapy. The rigorous definition of the target volume and the organs at risk required by these irradiation techniques, imposed the development of various image guided patient positioning and target tracking techniques. The availability of these imaging systems inside the treatment room has lead to the exploration of performing real-time adaptive radiation therapy. In this paper we present the different image guided radiotherapy (IGRT) techniques and the adaptive radiotherapy (ART) approaches. IGRT developments are focused in the following areas: 1) biological imaging for better definition of tumor volume; 2) 4D imaging for modeling the intra-fraction organ motion; 3) on-board imaging system or imaging devices registered to the treatment machines for inter-fraction patient localization; and 4) treatment planning and delivery schemes incorporating the information derived from the new imaging techniques. As this paper is included in the "Cancer-Radiotherapie" special volume dedicated to the lung cancers, in the description of the different IGRT techniques we try to present the lung tumors applications when this is possible.

Forecasting↗
PubMed2006

[Lung cancer: is there a place for elective nodal irradiation?].

The use of conformal radiotherapy in lung cancer has considerably evolved with the advent of improved staging technologies and methods of radiation delivery. Patients with limited disease, inoperable for medical reasons, may be treated with conformal radiotherapy alone; patients with more advanced disease are treated with combined chemo-radiotherapy. If local control may be improved by radiotherapy dose escalation according to several studies, toxicity and more particularly pulmonary toxicity seems to be related to radiation volume. Thus the use of elective nodal irradiation is being questioned. Data for early stage (stage I) non-small-cell lung cancer treated with conformal radiotherapy or stereotactic hypofractionated radiotherapy strongly supports the use of smaller fields that do not incorporate elective nodal regions; local control and survival rates approach those of surgical series. In locally advanced non-small cell lung cancer, eliminating elective nodal irradiation allows to maximize tumor dose and minimize normal tissue toxicity in combined modality treatments; results are encouraging. The use of staging modalities such as positron emission tomography and eventually oesophageal ultrasonography is increasing, allowing to encompass the tumor volume with more accuracy. Several studies have confirmed that involved-field irradiation results into a regional nodal rate of less than 10%. Further larger-scale studies would be needed to definitely establish "no elective nodal irradiation" as a standard in non-small cell lung cancer. There are very few data concerning small cell lung cancer.

Humans↗
PubMed2006

[Prophylactic cranial irradiation in non-small cell lung cancer].

Prophylactic cranial irradiation (PCI) has become part of the standard treatment in patients with small cell lung cancer (SCLC) in complete remission. Not only does it decrease the risk of brain recurrence by almost 50%, it has a significant positive effect on survival (5.4 percent increase at 3 years). As the prognosis of patients with locally advanced non-small cell lung cancer (NSCLC) has improved with combined modality treatment, brain metastases have also become an important cause of failure (10 to 30%, approaching 50% in certain studies as in SCLC). Survival after treatment of brain metastases is poor and impact on quality of life of patients is important. As in SCLC, 4 randomised evaluating PCI in NSCLC have been carried out in the seventies and early eighties. If 3 out of 4 trials have shown a significant decrease of brain metastases, none of them demonstrated any impact on survival. Thus PCI cannot be recommended as standard treatment in NSCLC, however new trials would be needed.

Brain Neoplasms↗
PubMed2006

[Image registration for radiation therapy: Practical aspects and quality control].

The development of conformal radiotherapy techniques (CRT) and intensity modulated CRT requires an accurate delineation of target structures and organs at risk. Thus, additional information provided by anatomical and/or functional imaging modalities can be used for volume of interest determination combined with traditionally used Computed Tomography imaging (CT): for instance, functional or morphological Magnetic Resonance Imaging (f MRI or m MRI) or Positron Emission Tomography (PET). A prerequisite to the simultaneous use of this information is image registration. Due to the differences between the images and the information they provide, a quality control of image registration process for radiotherapy is mandatory. The purpose of this article is to present the difficulties in implementing such controls and to show the necessity for a clinical validation on patient's images. The last part of this work presents the possible interest in using f MRI to help radio-oncologists in the treatment planning for gliomas associated to image coregistration and quality control considerations.

Brain Neoplasms↗
PubMed2006

A systematic review of environmental correlates of obesity-related dietary behaviors in youth.

There is increasing interest in the role the environment plays in shaping the dietary behavior of youth, particularly in the context of obesity prevention. An overview of environmental factors associated with obesity-related dietary behaviors among youth is needed to inform the development of interventions. A systematic review of observational studies on environmental correlates of energy, fat, fruit/vegetable, snack/fast food and soft drink intakes in children (4-12 years) and adolescents (13-18 years) was conducted. The results were summarized using the analysis grid for environments linked to obesity. The 58 papers reviewed mostly focused on sociocultural and economical-environmental factors at the household level. The most consistent associations were found between parental intake and children's fat, fruit/vegetable intakes, parent and sibling intake with adolescent's energy and fat intakes and parental education with adolescent's fruit/vegetable intake. A less consistent but positive association was found for availability and accessibility on children's fruit/vegetable intake. Environmental factors are predominantly studied at the household level and focus on sociocultural and economic aspects. Most consistent associations were found for parental influences (parental intake and education). More studies examining environmental factors using longitudinal study designs and validated measures are needed for solid evidence to inform interventions.

Adolescent↗
PubMed2006

Differences in measured and self-reported height and weight in Dutch adolescents.

BACKGROUND/AIMS: Monitoring overweight prevalence and its trends in Dutch youth is frequently based on self-reported data. The validity of self-reported data especially in young adolescents is not sufficiently known. The purpose of this study is to study the validity of self-reported height and weight in 12- to 13-year-olds, to identify sociodemographic correlates and to explore whether correction factors can be developed to estimate the prevalence of overweight in youth. METHODS: 5,525 12- to 13-year-old pupils in the Rotterdam area filled in a confidential questionnaire on health topics, including their height and weight. In a sub-sample of 499 pupils both self-reported and measured height and weight were available. RESULTS: Self-reported data led to a considerable underestimation of Body Mass Index and consequently the prevalence of overweight. Underestimation was higher in pupils who regarded themselves as more fat, were of non-Dutch origin and in lower education levels. CONCLUSION: Self-reported height and weight appeared to be inappropriate to estimate the overweight prevalence in 12- to 13-year-olds, unless the figures were adjusted. Using adjusted self-reported BMI on an individual level is questionable. Actual measurements of height and weight are necessary to draw up valid correction formulas in new samples.

Adolescent↗
PubMed2006

Diagnosis of respiratory bronchiolitis associated interstitial lung disease.

BACKGROUND: Respiratory Bronchiolitis (RB), described by Niewoehner et al in 1974, is a common finding in heavy smokers and is characterised by the presence of pigmented macrophages within respiratory bronchioles and adjacent alveoli. In the 1980s, Myers et al described RB associated with interstitial lung disease (RBILD), which is a rare entity expressed as an amplified respiratory bronchiolitis in response to cigarette smoke. METHODS: The authors studied a group of 8 patients with biopsy-proven RBILD diagnosed within the last five years, and assessed epidemiological data, clinical and imaging features, lung function tests, bronchoalveolar lavage findings, therapeutic approaches and clinical evolution. RESULTS AND CONCLUSIONS: The most difficult differential diagnosis is between RBILD and Desquamative Interstitial Pneumonia (DIP), which seems to suggest that these disorders are either end of the same spectrum, although the authors claim that there are some clinical, morphological and prognostic distinctions. The diagnosis of RBILD requires an appropriate clinical setting (including smoking habits), characteristic image findings (like ground glass shadowing and centrilobular nodules), and Bronchoalveolar Lavage (BAL) data to exclude other diagnosis. Pathological confirmation may also be important, not only to exclude more adverse interstitial lung disease, such as idiopathic pulmonary fibrosis, but also, as in the eight cases presented, to illustrate some specific features such as the prevalence of lymphocytosis in BAL.

Adult↗
PubMed2005

[Thoracic adenoid cystic carcinomas].

Adenoid cystic carcinomas in the trachea are rare, but represent around 40% of all tracheal tumours. Other intrathoracic localisations include the carena or proximal airways. Adenoid cystic carcinoma's growth rate is slow so that it is frequently diagnosed at an advanced stage. Pathological identification may be difficult. Treatment in limited tumours is based upon surgical resection often combined to radiotherapy because of close surgical margins. Radiotherapy dose may vary between 45 and 65 Gy according to margins status. Five-year survival rates of 65-80% have been reported after surgery or surgery and postoperative radiotherapy. Among inoperable patients treated with exclusive radiotherapy for tracheal tumours (including adenoid cystic but also squamous cell carcinomas of poorer prognosis), the recommended delivered dose should be over 60 Gy. Five-year survival rate in these very heterogeneous series may vary between 12 and 27%. Local or metastatic recurrences may occur very lately. They are considered chemo-resistant and targeted therapies may prove to be effective in the future.

Carcinoma, Adenoid Cystic↗
PubMed2003

Experience with enoxaparin in patients with mechanical heart valves who must withhold acenocumarol.

OBJECTIVES: To evaluate the incidence of thromboembolic and haemorrhagic events in a cohort of patients with mechanical heart valves who had to withhold acenocumarol and were treated with enoxaparin. DESIGN: Observational prospective study. SETTING: In hospital; after discharge, and follow up by telephone call. PATIENTS AND METHODS: All consecutive patients with mechanical heart valves admitted to the authors' hospital between May 1999 and January 2002 who had to interrupt treatment with acenocumarol and were treated with enoxaparin as an alternative to other methods were enrolled. In each patient, the following characteristics were prospectively determined: the reason for interrupting acenocumarol, demographic data, estimated global risk for thromboembolic events, international normalised ratio before starting enoxaparin treatment, number of days taking enoxaparin, and mean level of anti-Xa activity during treatment. All patients were followed up through clinical history during the hospitalisation and by telephone after discharge to detect thromboembolic events. MAIN OUTCOME MEASURE: Presence of thromboembolic or haemorrhagic events. RESULTS: 82 patients were identified and followed up for a mean of 2.8 months (range 1.5-3.5 months) after discharge. 61 of them (74%) had one or more associated thromboembolic risk factors. Acenocumarol was interrupted (to perform an invasive procedure in 74 patients and because of haemorrhagic complication in 8) an average of 11.2 days (range 3-40 days). Most patients received the standard enoxaparin dose (1 mg/kg at 12 hour intervals). Mean (SD) anti-Xa activity was 0.58 (0.3) IU/ml (median 0.51). There were 8 minor and 1 major bleeding events during enoxaparin treatment. No thromboembolic complications were clinically detected during hospitalisation or during follow up (95% confidence interval 0% to 3.6%). CONCLUSIONS: Enoxaparin may be an effective and relatively safe substitute anticoagulant for patients with mechanical heart valves who must withhold acenocumarol.

Acenocoumarol↗
PubMed2002

Current and adolescent levels of cardiopulmonary fitness are related to large artery properties at age 36: the Amsterdam Growth and Health Longitudinal Study.

BACKGROUND: High levels of cardiopulmonary fitness (VO2max) are associated with reduced risk of cardiovascular morbidity and mortality, but little is known to what extent this is related to the effects of cardiopulmonary fitness on atherosclerosis and arterial stiffness. Moreover, the time course of these relationships needs to be elucidated. We sought to investigate (i) the cross-sectional relationship between VO2max and carotid atherosclerosis and carotid and femoral arterial stiffness at age 36, as well as (ii) the relationship between VO2max during adolescence (13-16 years) and the same arterial properties at age 36 (prospective analyses). DESIGN: Cross-sectional analyses consisted of 351 subjects (183 women) and the prospective analyses of a subpopulation of 154 subjects (79 girls). Arterial properties were assessed noninvasively by ultrasound imaging; VO2max was measured with a maximal running text on a treadmill with direct measurements of oxygen uptake. RESULTS: After adjustment for confounding by other known risk factors, current and adolescent levels of VO2max were independently associated with carotid intima-media thickness (beta = -0.288, P = 0.004 and beta = -0.381, P = 0.012) in men, and with the diameter of the femoral artery (beta = 0.375, P < 0.001 and beta = 0.252, P = 0.026, respectively) in both sexes. Current levels of VO2max were positively associated with the compliance of the carotid and the femoral arteries (beta = 0.186, P = 0.023 and beta = 0.183, P = 0.033, respectively), and with the distensibility of the carotid (beta = 0.162, P = 0.047) but not the femoral artery. CONCLUSION: We conclude that cardiopulmonary fitness is associated with large artery properties at age 36, and that the roots of this association may already be present in adolescence.

Adolescent↗
PubMed2001

Critical appraisal of clinical practice guidelines targeting chronic obstructive pulmonary disease.

BACKGROUND: Chronic obstructive pulmonary disease (COPD) is so prevalent that the endorsement of management strategies by professional organizations issuing clinical practice guidelines (CPGs) will likely influence the clinical and financial resources allocated to this condition. OBJECTIVES: To examine the content of and to critically appraise the CPGs targeting COPD. METHODS: We identified, through a MEDLINE search (from January 1990 to May 1999) and contacts with experts and professional organizations, the CPGs for the overall management of COPD. We assessed the guidelines according to an index of quality measuring 3 dimensions: the rigor of development, the context and content, and the extent to which the dissemination and implementation have been addressed. The recommendations were also examined and compared. RESULTS: Of the 15 CPGs we included, none was based on a systematic review of the literature. Two were independently reviewed before their release, 1 included strategies for dissemination and implementation, and 1 estimated the economic implications associated with its recommendations. The recommendations were often difficult to interpret (reviewers' agreement: kappa median, 0.41). When unanimity existed regarding the benefits of a given management modality (such as respiratory rehabilitation), discrepancies were often identified in the application of the recommendation. CONCLUSIONS: The methodological quality of CPGs targeting COPD is limited, and there are disparities among many of their recommendations. Despite there being several CPGs worldwide, there is a need for an evidence-based summary of the literature to serve as a resource for those who provide health care to individuals with COPD.

Evidence-Based Medicine↗
PubMed2001

Omapatrilat: neurohormonal and pharmacodynamic profile when administered with furosemide.

Pharmacodynamic effects of combination therapy with omapatrilat and furosemide were evaluated. Two groups of 13 healthy subjects each received furosemide 20 mg dailyfor 15 days coadministered with either placebo on days 6 to 15 or omapatrilat 10 mg on days 6 to 10 and 25 mg on days 11 to 15. In the omapatrilat group, urinary excretion of atrial natriuretic peptide increased, and greater blood pressure reductions were seen compared with placebo. Concomitant omapatrilat treatment did not affect the acute diuresis, natriuresis, and kaliuresis observed with chronic administration of furosemide. Neither effective renal plasma flow nor glomerularfiltration rate changed in either treatment group. No clinically significant safety issues were observed. Daily coadministration of omapatrilat 10 or 25 mg with furosemide 20 mg does not affect the pharmacodynamics offurosemide at steady state.

Adult↗
PubMed2001

International approaches to the prescription of long-term oxygen therapy.

While there is broad agreement about who should receive long-term oxygen therapy (LTOT), there is little information available on how clinicians should decide on the oxygen prescription itself, at rest, during sleep and during exercise. The authors describe the results of an international survey that was undertaken to compare how respirologists prescribed oxygen. A questionnaire was sent to 100 respirologists in each of seven countries. The questionnaire identified whether resting flow rates were derived in a standard manner or by individualized patient testing. Test targets were ascertained for rest, exercise and sleep, as was the percentage of time that each test target had to reach for the test to be accepted. The majority of respondents individualized the oxygen prescription at rest (81%). Resting arterial oxygen saturation (Sa,O2) was most commonly targeted at 90-91%. The approach to night prescription varied (p<0.001). Respirologists in Canada and the USA increased the resting Sa,O2 by 1-2 L x min(-1) during sleep, while those in Spain used the resting (awake) flow for the night prescription (62%). Respirologists in the Netherlands, France, and Italy individualized the night prescription more frequently. Although oxygen during exercise was individualized in most countries (74%), significant differences remained among countries (p<0.001). The majority of respirologists (62%) aimed to achieve an Sa,O2 of 90-91% during exercise, while 70% of all respirologists tried to achieve the desired Sa,O2 for 90% of the test. There were substantial differences among countries as to how the oxygen prescription was written. This survey highlights the need for multicentre studies that improve the effectiveness of long-term oxygen therapy utilization.

Adult↗
PubMed2001

Nutritional intervention in COPD: a systematic overview.

OBJECTIVE: We conducted a systematic overview of randomized controlled trials (RCTs) to clarify the contribution of nutritional supplementation for patients with stable COPD. METHODS: RCTs were identified from several sources, including the Cochrane Airways Group register of RCTs, a hand search of abstracts presented at international meetings, and consultation with experts. Two reviewers independently selected trials for inclusion, assessed quality, and extracted the data. RESULTS: Twenty-one reports were classified according to the type, duration of supplementation, and the presence of anabolic substances. High carbohydrate meals were associated with an increase in carbon dioxide production and a decrease in exercise capacity. Short-term crossover studies in which diets of various compositions were administered supported the notion that high carbohydrate loads increase the stress on the ventilatory system. The influence of longer-term supplementation (> 2 weeks) on weight, anthropometry, and exercise capacity varied, without there being a consistent effect. Lean body weight was only occasionally reported and health-related quality of life too rarely to be included as an outcome. The influence of recombinant human growth hormone was disappointing. Anabolic steroids increased body weight and lean body mass, but had little influence on exercise capacity. CONCLUSION: This systematic overview in patients with COPD supports the notion that those with marginal ventilatory reserve might benefit from a dietary regimen in which a high percentage of calories are supplied by fat. Although there are reports of the benefits of nutritional repletion, trials of > 2 weeks failed to show consistent benefit on body weight. Evaluating nutritional repletion is hampered by the absence of information regarding body composition, exercise, and health-related quality of life. Growth hormone has not been shown to be useful. Further studies are needed to refine the beneficial effects of anabolic steroids as adjunctive agents together with nutritional support and exercise.

Anabolic Agents↗
PubMed2001

Effect of food on the oral bioavailability of UFT and leucovorin in cancer patients.

UFT is composed of tegafur (FT), a prodrug of 5-fluorouracil (5-FU), and uracil in a fixed combination (1:4). In conjunction with leucovorin, UFT is being developed for the first-line oral treatment of metastatic colorectal cancer. The effect of food on the oral bioavailability of UFT (2 x 100 mg capsules; dose in terms of FT) and leucovorin (2 x 15 mg tablets) was evaluated in a single-dose, randomized, two-way crossover study. Patients (n = 25) were assigned to receive both drugs after an overnight fast or 5 min after completion of a high-fat meal (721 calories) with a 3-day washout period between treatments; then they were permitted to continue on oral UFT/leucovorin therapy for safety assessment. UFT (300 mg/m2/day as three divided doses) and leucovorin (90 mg/day as three divided doses) were given for 28 days. After a 7-day rest, the 28-day cycle was repeated. Pharmacokinetics (n = 22 patients) were determined for FT, 5-FU, uracil, leucovorin, and 5-methyltetrahydrofolate (an active metabolite of leucovorin). The absence of food-effect on peak plasma concentration (CMAX) and the area under the curve (AUC) was concluded if the 90% confidence interval for the ratio of the treatment means was entirely contained in 0.75-1.33. Administration of UFT with food resulted in a 34% decrease in CMAX of FT, whereas the AUC of FT remained unchanged. Food decreased the CMAX and AUC values of uracil and 5-FU by 37-76%. On the contrary, the CMAX and AUC values of leucovorin and 5-methyltetrahydrofolate were increased by 14-60% with food. Time to reach CMAX for all analytes was significantly (P < or = 0.001) delayed by food. Except for the AUCs of FT, the statistical criterion for concluding a lack of food-effect was not met. These data suggest that UFT/leucovorin should not be dosed simultaneously with food. It is recommended that food should not be consumed for 1 h before and after an oral dose of UFT and leucovorin in a manner similar to pivotal Phase III trials. The 28-day oral regimen of UFT and leucovorin was generally well tolerated in the population studied.

Administration, Oral↗
PubMed2000

A comparative description of three multipurpose phantoms (MPP) for external audits of photon beams in radiotherapy: the water MPP, the Umeå MPP and the EC MPP.

AIM: To present a technical description and intercomparison of three multipurpose phantoms (MPP) developed for mailed dosimetry checks of therapeutic photon beams in reference and non-reference conditions. MATERIALS: The W-MPP is a water MPP, whereas the Umeâ-MPP, made of perspex (PMMA, Plexiglas), and the EC-MPP, made of polystyrene, are solid MPPs. The W-MPP uses only thermoluminescent dosimeters (TLD) for dosimetry checks, the EC MPP uses film and TLD; the Umeâ phantom uses film and TLD, and offers in addition the possibility for ionization chamber measurements. Either using TLD or films, the MPPs have been designed to check on-axis and off-axis the following irradiation conditions: square and rectangular fields, asymmetric fields, wedged beams, oblique incidence and, for the solid MPPs, also the influence of inhomogeneities. RESULTS AND DISCUSSION: The MPPs have been compared for different aspects going from their dosimetric performance (number of dosimetric parameters that can be checked) to some practical consideration in the use of the different MPPs (set-up time, stability, instruction sheets, etc.). From a comparison between the solid multi-purpose phantoms, it turns out that the EC-MPP is capable of checking the largest number of dosimetric parameters per beam, but has the longest set-up time ( approximately 2 h) per beam according to the users. The Umeå-MPP has a smaller number of set-ups (hence a smaller average time) and also includes some parameters not checked with the EC-MPP (e.g. SSD accuracy). The major drawback however of the Umeå-MPP is considered to be its high density (>1.1 g/cm(3)) which increases the difficulty of the analysis with the treatment planning system. The W-MPP checks the smallest number of parameters, but is the fastest in set-up time, the easiest for mailing, and is water equivalent, which is advantageous for the TPS checks. The major drawback of this MPP is however the inability to check complete dose distribution (film) or inhomogeneities.

Equipment Design↗