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Biomedical subjects

F Márquez

Publications and source records attributed to F Márquez.

At least 19 recordsLinked to original sources
PubMed2006

Evaluation of readmissions in hematopoietic stem cell transplant recipients.

BACKGROUND: There is a lack of information on health expenses caused by readmissions among hematopoietic stem cell transplant (HSCT) recipients. We analyzed the rate, causes, and evolution of hospitalization after HSCT. METHODS: We retrospectively studied 140 consecutive patients who received an autologous HSCT (n = 107; 76.4%) or an allogeneic HSCT (n = 33; 23.6%) in our institution from May 2001 through September 2004. RESULTS: There were 45 readmissions in 28 patients (20%): three (10%) in the autologous and 25 (90%), in the allogeneic HSCT cohorts. The overall median age was 35.3 +/- 13.5 years and 54% were women. Hematologic diseases were: multiple myeloma (n = 1, 4%), myelodysplastic syndrome (n = 2, 7%), acute lymphoblastic leukemia (n = 2, 7%), aplastic anemia (n = 2, 7%), chronic myeloid leukemia (n = 3, 11%), non-Hodgkin's lymphoma (n = 4, 14%), Hodgkin's disease (n = 4, 14%) and acute nonlymphoblastic leukemia (n = 10, 38%). The length of stay for each readmission was 25 +/- 21 days. The median day of readmission was +62.5 (range = +19 to +987); however, 75% occurred between days +30 and +70. The causes of hospitalization were: infections (n = 24, 54%), due to the graft (n = 14, 31%), graft failure (n = 4, 9%), coagulation disorders (n = 2, 4%), and second neoplasm (n = 1, 2%). Mortality due to the transplant was 10 patients (14%) including: graft-versus-host disease (n = 3), sepsis (n = 3), thrombotic thrombocytopenic purpura (n = 1), and relapse (n = 3). CONCLUSIONS: Although there was a frequent use of hospital resources (20%) after HSCT with patients hospitalized for a median of 25 days, it was beneficial since there were 86% survivors at 36 months follow-up.

Adult↗
PubMed2005

The vibrational spectra of (CH3)3SiX (S=H, F, Br) molecules, revisited Transferable scale factor sets for methylsilane derivatives.

The joint experimental and theoretical study of the vibrational spectra of the molecular series (CH3)3SiX (with X=H, F and Br) is carried out. Data from newly recorded IR and Raman spectra for the bromo derivative, experimental data obtained previously for the remaining species, DFT theoretical calculations and the use of the SQMFF procedure have allowed us to propose common patterns and to unify criteria in their assignment. In addition, two sets of averaged scale factors for the B3LYP force field obtained with two different basis sets (6-31G* and DZP+diff) have been proposed for the common bulky moiety of that molecular series. These parameters were used successfully in order to reproduce the frequency of the bands assigned to the (CH3)3Si- group in the vibrational spectra of the corresponding silanolic and methoxy derivatives, i.e., trimethylsilanol and methoxytrimethylsilane, proving their transferability.

Spectroscopy, Fourier Transform Infrared↗
PubMed2005

Modulation of the photophysical properties of C60 by electronic confinement effect.

This research work reports on the incorporation of fullerene C60 in diverse inorganic and organic matrixes and how these different environments induce changes on the photophysical properties of the molecule depending on the cavity dimensions of the host. Indeed the fluorescence emission band of C60 experiences a progressive bathochromic shift with respect to C60 in solution as the cavity dimensions of the host decrease in going from the mesoporous material MCM41 to UTD-1 and Na-Y zeolites. This experimental observation, which has been documentarily confirmed by theoretical predictions and recent experimental results, is a reflection of the confinement effect imposed by the host. However, the most striking result reported in this work is that the fluorescence range accessible to this occluded species can be extraordinarily extended by confinement inside the neutral cages of a "dendritic box". The ability of the dendritic shell to create a microenvironment, modifying the properties of its functional core, allows the emission bands of C60 incorporated into a dendrimer to be effectively red-shifted with respect to their emission in solution, and, contrarily to other confined spaces of considerable hardness such as zeolites or the high surface material MCM41, the magnitude of this shifting is maximum and can be modulated under appropriate experimental conditions. This phenomenon has an enormous relevance since it can be exploited in future technological applications.

Journal Article↗
PubMed2005

Vibrational spectrum of chlorotrimethylsilane.

The IR and Raman spectra of chlorotrimethylsilane (CTMS) were re-examined. Gas and liquid phase spectra were newly recorded and the analysis of the second derivatives of intensities in some complex spectral regions was carried out. The experimental study was combined with theoretical calculations at the B3LYP level with two different basis sets, i.e., 6-31G(*) and DZP+diff. The use of the SQM methodology, allowed us to review the assignment of the bands for nu(3) (methyl deformation), nu(5) (methyl rocking) and nu(8) (SiC deformation) normal modes of A(1) symmetry, as well as nu(16), nu(17) (methyl deformations) and nu(20) (methyl rocking) normal modes of E symmetry. The description of the asymmetric CH stretchings spectral region has been improved and, in addition, new values of vibrational frequencies were predicted for A(2) normal modes, inactive in both IR and Raman spectra. The equilibrium geometry parameters of CTMS obtained in this work at the MP2/DZP+diff level are closer to the experimental values than previous predictions.

Models, Molecular↗
PubMed2004

Mucus physiopathology, update and new therapeutic tendencies.

The knowledge of mucous secretions has advanced considerably with respect to their altered physiological properties in various ear, nose and throat disorders. We review the physicochemical properties of normal mucus and abnormal mucus present in the airways during sinusitis, otitis media with effusion, etc. We have adapted the mucoactive drugs classification to the up-to-date european situation, presenting a bibliographic review. We have attempted to reconcile the agreed findings in the literature with the most recent advances in research that have resulted in new therapeutic strategies for the treatment of pathological hypersecretion in the airways.

Drug Therapy↗
PubMed2003

[Lymphoma of the nasal cavity, clinical and anatomo-pathologic considerations].

Six cases of high-grade lymphoma affecting the nasal cavity are presented. Their main symptoms were nasal obstruction, epistaxis and rhinorrea. Clinical exploration showed an ulcerated lesion in four patients (all of them T/NK cell lymphomas) and an exofitic tumour in the other two (B cell lymphomas). Pathology was diagnostic for high grade lymphoma in all the six cases, immunohistochemical studies revealed that the atypical cells were T/NK in 4 cases and B in the other two cases. Genotypic analysis was done looking for rearrangement of the genes for Ig H or T-cell receptors. In situ hybridisation was done to detect Epstein-Barr virus RNA. Malignant lymphomas arising in the nasal cavity are unusual, its major prognostic factor is the clinical stage at presentation. To perform an early diagnosis this neoplasia must be suspected in the presence of an exofitic tumour (B cell lymphoma) or necrotic and ulcerated lesion (T/NK cell lymphoma).

Adolescent↗
PubMed1992

Some morphologic changes induced by Nd:YAG laser on the noncoated enamel surface: a scanning electron microscopy study.

The enamel surface layer of some human teeth was treated with the low-energy Nd:YAG laser at 8 mJ pulse energy. These samples were previously etched with 0.05 M orthophosphoric acid to reduce the surface reflection. The treated samples, as well as the control samples, were widely studied by scanning electron microscopy, and, in the lased group, significant morphologic changes affecting the enamel surface were observed. Those changes reveal principally the loss of the typical surface structure of the acid-etched enamel. The hydroxyapatite prisms were not discernible, and there was a decrease in the roughness of the lased surface enamel. These laser-induced structural changes may be related to the increased resistance to the calcification reported by many authors.

Acid Etching, Dental↗
PubMedDate not supplied

[Giant ethmoid neurinoma with intracranial extension].

The schwannomas are tumors arising from nervous tissue. It appears very rarely in the nose and paranasal sinuses. Intra and extracraneal extension of these tumors are even more uncommon. In this paper we report a case of a esfeno-ethmoidal schwannoma with anterior skull fossa extension. We describe the CT scan and magnetic resonance imaging and the histological features. Surgical resection was carried through a craniofacial approach. Some data about diagnosis, treatment and outcome of these tumors are revised.

Aged↗
PubMedDate not supplied

Nasal hyperreactivity to methacholine measured by acoustic rhinometry in asymptomatic allergic and perennial nonallergic rhinitis.

This study was carried out to assess nasal response to different doses of methacholine and to evaluate the diagnostic possibilities of this test. Thirty-seven patients with allergic rhinitis induced by pollen (out of season), 16 with nonallergic rhinitis, and 25 normal subjects were evaluated. After provocation with saline, increasing doses of methacholine, ranging from 0.5 to 16 mg/mL, were applied. Nasal obstruction was assessed by acoustic rhinometry 10 minutes after each dose, the minimum cross-sectional area and the nasal volume in both fossae were obtained. Ipratropium bromide was applied after the last dose of methacholine to evaluate reversibility. After methacholine challenge with 0.5, 1, 2, and 4 mg/mL there was a statistically significant decrease (p < 0.05) in nasal area and volume in a dose-dependent manner in patients with allergic and nonallergic rhinitis in comparison with controls. A ROC (receiver-operating characteristic) analysis showed that a decrease in nasal volume > or = 20% at methacholine concentration of 2 mg/mL is able to predict the presence of rhinitis (positive predicted value 93%, negative predicted value 79%) in 75% of subjects. The clinical relevance of this finding suggests that patients with symptomatic nonallergic rhinitis or even asymptomatic patients with allergic rhinitis out of pollen season present a nasal hyperreactivity to methacholine, and that a decrease of nasal volume > 20% by acoustic rhinometry after challenge with methacholine at 2 mg/mL is able to discriminate these patients from normal subjects. This method seems to be a suitable tool in the diagnosis of rhinitis.

Acoustics↗