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Biomedical subjects

C Fernandez

Publications and source records attributed to C Fernandez.

At least 55 records · Page 3Linked to original sources
PubMed2001

High-resolution X-ray spectroscopy of rare events: a different look at local structure and chemistry.

The combination of large-acceptance high-resolution X-ray optics with bright synchrotron sources permits quantitative analysis of rare events such as X-ray fluorescence from very dilute systems, weak fluorescence transitions or X-ray Raman scattering. Transition-metal Kbeta fluorescence contains information about spin and oxidation state; examples of the characterization of the Mn oxidation states in the oxygen-evolving complex of photosystem II and Mn-consuming spores from the marine bacillus SG- are presented. Weaker features of the Kbeta spectrum resulting from valence-level and 'interatomic' ligand to metal transitions contain detailed information on the ligand- atom type, distance and orientation. Applications of this spectral region to characterize the local structure of model compounds are presented. X-ray Raman scattering (XRS) is an extremely rare event, but also represents a unique technique to obtain bulk-sensitive low-energy (<600 eV) X-ray absorption fine structure (XAFS) spectra using hard (approximately 10 keV) X-rays. A photon is inelastically scattered, losing part of its energy to promote an electron into an unoccupied level. In many cases, the cross section is proportional to that of the corresponding absorption process yielding the same X-ray absorption near-edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) features. XRS finds application for systems that defy XAFS analysis at low energies, e.g. liquids or highly concentrated complex systems, reactive compounds and samples under extreme conditions (pressure, temperature). Recent results are discussed.

Bacillus↗
PubMed2001

Signal transduction through Vav-2 participates in humoral immune responses and B cell maturation.

B and T lymphocytes develop normally in mice lacking the guanine nucleotide exchange factor Vav-2. However, the immune responses to type II thymus-independent antigen as well as the primary response to thymus-dependent (TD) antigen are defective. Vav-2-deficient mice are also defective in their ability to switch immunoglobulin class, form germinal centers and generate secondary immune responses to TD antigens. Mice lacking both Vav-1 and Vav-2 contain reduced numbers of B lymphocytes and display a maturational block in the development of mature B cells. B cells from Vav-1(-/-)Vav-2(-/-) mice respond poorly to antigen receptor triggering, both in terms of proliferation and calcium release. These studies show the importance of Vav-2 in humoral immune responses and B cell maturation.

Animals↗
PubMed2001

Assessment of in vivo complement activation on the Echinococcus granulosus hydatid cyst wall.

The larval stage of the parasite Echinococcus granulosus causes hydatid disease. The hydatid cyst is potentially capable of activating host complement, since it is a large, persistent, carbohydrate-rich structure, coated with host immunoglobulins, and localized in the host's internal organs. Nonetheless, in vitro studies have suggested that the cyst surface, the hydatid cyst wall (HCW), is a poor complement activator. In this study, we assessed the occurrence of in vivo complement activation on the hydatid cyst by measuring the levels of two complement activation products, C3d and complexes bearing a C9 activation neoepitope (TCC/MAC), in extracts from HCW of human origin. Low amounts of C3d and TCC/MAC were found in HCW in comparison with their levels in normal human plasma and activated human sera, suggesting that in vivo complement activation on HCW is efficiently down-regulated. This regulation may contribute to limit host inflammation which has been observed to correlate with parasite degeneration and death.

Animals↗
PubMed2001

Paediatric day-case surgery in a district general hospital: a safe option in a dedicated unit.

Currently, there is a trend towards the centralisation of paediatric surgery in specialist regional units. This study reports the results of 4 years' experience of paediatric day-case surgery in a dedicated unit within a district general hospital. Since its inception in 1993, data have been collected on all individuals undergoing surgery. Between 1993-1997, 804 operations were performed with 80% of procedures being undertaken by a consultant. There were 7 (< 1%) known complications and 7 (< 1%) patients required admission postoperatively. These results compare favourably with those of specialist institutions.

Adolescent↗
PubMed2001

[Criteria of low risk of mortality in children with neutropenia and fever during cancer chemotherapy].

To validate the use of a lower-risk mortality profile in pediatric febrile neutropenia during anticancer therapy and to evaluate the efficacy of a sequential parenteral-oral antibiotic treatment for these children, a prospective study was conducted between May 1997 and December 1999. During this period 247 episodes in 215 patients were included in the present study. Children with neutropenia (ANC < 500/mm3) and fever (> 38 degrees C) due to anticancer therapy were eligible for the study if they presented the following lower-risk conditions: absence of severe co-morbidity factors, good clinical condition, no risk clinical foci, no bacteremia, and responsible parents. They were initially treated with inpatient parenteral short course of ceftriaxone and amikacin followed by ambulatory oral cefixime or ciprofloxacin to complete 7 days. Mean age was 64 (range: 8-200) months. The most common underlying malignant disease was acute lymphoblastic leukemia in 48% (118) of cases and 57% (141) of patients had an indwelling central venous catheter. Clinical evidence of infection was found in 47% (122) of children and the most common site was the upper respiratory tract (81%). Mean period of fever was 1.1 days (r: 1-8) and the duration of neutropenia was 3.9 days (r: 1-9). Sixty-one% (150) of children was discharged with neutropenia. Mean time of hospitalization was 1.5 days. Four clinical failures were detected (1.6%). They all were satisfactorily treated with a secondary treatment and none underwent any major complications or died. The lower-risk profile used was safe and the sequential antibiotic therapy was adequate to manage febrile neutropenia in this subset of children.

Adolescent↗
PubMed2001

[Value of cytokeratin 7 and 20 for the diagnosis of cerebral metastases of adenocarcinoma: study of 78 cases].

OBJECTIVE: histological features of metastasis are not always specific of the origin. The usefulness of cytokeratin 7 and 20 (CK7 and CK20) in cerebral metastases from an adenocarcinoma was studied in a series of 78 patients. RESULTS: metastases from lung adenocarcinoma showed a CK7+/CK20- pattern in 79% of cases, CK7+/CK20+ in 19% and CK7-/CK20- in 2%. When observed, positivity for cytokeratin 20 was generally focal or weak. Breast adenocarcinoma metastases were CK7+/CK20- in 71% of cases and CK7-/CK20- in 29%. Less differentiated tumours were usually negative for both cytokeratins. Metastases by colonic adenocarcinoma were CK7-/CK20+ in 100% of cases. Cytokeratins 7 and 20 are useful to distinguish lung from colonic metastatic carcinoma. In case of double positivity, a more intense CK7 expression is rather suggestive of a lung origin. CONCLUSION: these results might modify paraclinic investigations in search of the primitive tumor.

Adenocarcinoma↗
PubMed2001

[Atypical teratoid and rhabdoid tumor. Report of a congenital case].

The atypical teratoid rhabdoid tumor is a rare brain tumor of childhood. We report a congenital case, revealed by peripheral facial palsy. This polymorphous tumor consisted of rhabdoid cells associated with areas of primitive neuroectodermal tumor. The immunoreactivity for the three proteins vimentin, epithelial membrane antigen and smooth-muscle actin was suggestive of rhabdoid tumor. Genetic study showed a homozygous mutation in the tumoral DNA and a constitutional heterozygous mutation, as it was demonstrated in atypical teratoid rhabdoid tumors and in renal and extra-renal rhabdoid tumors.

Actins↗
PubMed2001

An intervention to increase quality of life and self-care self-efficacy and decrease symptoms in breast cancer patients.

This study tested effects of a nurse-administered self-efficacy intervention given on five monthly occasions and designed to enhance patients' self-care self-efficacy. The hypotheses were that at four months and eight months after beginning chemotherapy the efficacy-enhancing experimental group would have significantly higher scores on quality of life and self-care self-efficacy than the control group and significantly less symptom distress. Fifty-six women receiving chemotherapy for breast cancer were randomized to the experimental and control groups. Outcome variables were quality of life, measured by the Functional Assessment of Cancer Treatment-Breast (FACT-B), symptom distress, measured by the Symptom Distress Scale (SDS), and factors of self-care self-efficacy, measured by Strategies Used by Patients to Promote Health (SUPPH). The interaction effects for the FACT-B ranged from small for functional concerns (eta square = .03) to large for social concerns (eta square = .110); effects for the SDS were large (eta square = .140), and for factors on the SUPPH effect sizes ranged from small (eta square = .01) for Enjoying Life and Stress Reduction to medium (eta square = .089) for Coping, and large (eta square = .141) for Making Decisions. Interventions to promote self-efficacy may increase quality of life and decrease symptom distress for women diagnosed with breast cancer.

Adaptation, Psychological↗
PubMed2000

Resistance of natural killer T cell-deficient mice to systemic Shwartzman reaction.

The generalized Shwartzman reaction in mice which had been primed and challenged with lipopolysaccharide (LPS) depends on interleukin (IL)-12-induced interferon (IFN)-gamma production at the priming stage. We examined the involvement in the priming mechanism of the unique population of Valpha14 natural killer T (NKT) cells because they promptly produce IFN-gamma after IL-12 stimulation. We report here that LPS- or IL-12-primed NKT cell genetically deficient mice were found to be resistant to LPS-elicited mortality. This outcome can be attributed to the reduction of IFN-gamma production, because injection of recombinant mouse IFN-gamma, but not injection of IL-12, effectively primed the NKT cell-deficient mice. However, priming with high doses of LPS caused mortality of severe combined immunodeficiency, NKT cell-deficient, and CD1-deficient mice, indicating a major contribution of NKT cells to the Shwartzman reaction elicited by low doses of LPS, whereas at higher doses of LPS NK cells play a prominent role. These results suggest that the numerically small NKT cell population of normal mice apparently plays a mandatory role in the priming stage of the generalized Shwartzman reaction.

Animals↗
PubMed2000

Premedication with EMLA cream for ambultory surgery in children.

Objectives: The objective of this study was to confirm the ability of EMLA(R) cream (Eutectic Mixture of Local Anaesthetics, Astra, Sweden) to provide effective dermal analgesia after topical application on the skin of the dorsum of the hand 1 h before venous cannulation for anaesthetic induction. Material and Methods: Prospective, randomized, double blind study. We included 100 children, ASA I-III, distributed into three groups: Group EMLA (E, n=34), Placebo (P, n=33) and Control (C, n=33). Results: The EMLA group of patients (E) refered an evaluation of pain (visual analogical scale (mean=2.34+/-2.41), significantly smaller than the other groups (Placebo=5.54+/-3.40, Control=6.03+/-2.77). Conclusion: EMLA cream, when topically applied 1 h before venous cannulation, provides effective dermal analgesia for venous cannulation. No general or local adverse reactions were observed.

Journal Article↗
PubMed2000

Oral administration of cefixime to lower risk febrile neutropenic children with cancer.

BACKGROUND: Febrile neutropenia is a heterogeneous condition. Recently, several risk factors have been defined, permitting the definition of a lower risk group of patients who may benefit form less aggressive therapy. The use of an oral antibiotic approach was tested in the current trial. METHODS: From May 1997 to March 1998, 154 episodes of lower risk febrile neutropenia in 128 children with a mean age of 62 (range, 8-200) months were enrolled in this randomized, single-institution trial. Inclusion criteria were fever (> 38 degrees C), neutropenia (absolute neutrophil count < 500/mm(3)), lower risk features (i.e., absence of severe comorbidity factors, good clinical condition, negative blood cultures, control of local infection, no fever during the last 24 hours), and compliance of parents. After 3 days of ceftriaxone (100 mg/kg/day administered intravenously [i.v.]) every 12 hours plus amikacin (15 mg/kg/day i.v.) every 24 hours for 3 days, all patients were discharged and randomized to be allocated to 2 treatment arms. Group A (n = 74) received ceftriaxone cefixime (8 mg/kg/day administered orally) every 24 hours for 4 days, whereas Group B (n = 80) was treated with ceftriaxone plus amikacin for 7 days. Failure was defined as the need for second hospitalization during the same episode of neutropenia, or fever during the 7 days after discharge. RESULTS: Most of the patients (49% in Group A and 55% in Group B) had acute leukemia. Fifty-four (72%) children in Group A and 46 (56%) in Group B had fever of unknown origin (P = not significant [NS]). No significant differences were found in the sites of initial infection between the two groups. Overall results were outstanding, with a favorable outcome in 73 of 78 cases (98.6%) in Group A and 78 of 80 cases (97.5%) in Group B (P = NS). Three patients needed a second hospitalization due to failure of the initial therapy: one in Group A and two in Group B. All three did well with secondary treatment. CONCLUSIONS: In lower risk febrile neutropenic children receiving anticancer therapy, the efficacy of oral cefixime, given for 4 days after 72 hours of intravenous ceftriaxone plus amikacin, was similar to that of 7 days of parenteral ceftriaxone plus amikacin. The oral outpatient therapy approach to the treatment of lower risk febrile neutropenia after chemotherapy is safe and may be cost-saving. This strategy might be adopted as standard therapy in the future.

Administration, Oral↗
PubMed2000

The ADP-ribosylating CTA1-DD adjuvant enhances T cell-dependent and independent responses by direct action on B cells involving anti-apoptotic Bcl-2- and germinal center-promoting effects.

We recently developed a novel immunomodulating gene fusion protein, CTA1-DD, that combines the ADP-ribosylating ability of cholera toxin (CT) with a dimer of an Ig-binding fragment, D, of Staphylococcus aureus protein A. The CTA1-DD adjuvant was found to be nontoxic and greatly augmented T cell-dependent responses to soluble protein Ags after systemic as well as mucosal immunizations. Here we show that CTA1-DD does not appear to form immune complexes or bind to soluble Ig following injections, but, rather, it binds directly to B cells of all isotypes, including naive IgD+ cells. No binding was observed to macrophages or dendritic cells. Immunizations in FcepsilonR (common FcRgamma-chain)- and FcgammaRII-deficient mice demonstrated that CTA1-DD exerted unaltered enhancing effects, indicating that FcgammaR-expressing cells are not required for the adjuvant function. Whereas CT failed to augment Ab responses to high m.w. dextran B512 in athymic mice, CTA1-DD was highly efficient, demonstrating that T cell-independent responses were also enhanced by this adjuvant. In normal mice both CT and CTA1-DD, but not the enzymatically inactive CTA1-R7K-DD mutant, were efficient enhancers of T cell-dependent as well as T cell-independent responses, and both promoted germinal center formation following immunizations. Although CT augmented apoptosis in Ag receptor-activated B cells, CTA1-DD strongly counteracted apoptosis by inducing Bcl-2 in a dose-dependent manner, a mechanism that was independent of the CD19 coreceptor. However, in the presence of CD40 stimulation, apoptosis was low and unaffected by CT, suggesting that the adjuvant effect of CT is dependent on the presence of activated CD40 ligand-expressing T cells.

Adjuvants, Immunologic↗
PubMed2000

Stereospecific versus nonstereospecific assessments for the bioequivalence of two formulations of racemic chlorpheniramine.

Chlorpheniramine (chlorphenamine, CPAM) is a racemic antihistaminic H1 drug containing two enantiomers. The aim of this study was to assess the bioequivalence of two formulations (reference and Vietnamese-tested formulation) of racemic chlorpheniramine combined with phenylpropanolamine in an open-labeled, randomized, crossover two-period study, after administration of 8 mg of racemic chlorpheniramine in 12 healthy Vietnamese subjects. First, dissolution of both formulations was tested in vitro according to USP requirements. Then the 12 subjects received both formulations after an overnight fast and a 7-day wash-out period. Plasma samples were collected up to 168 h. Plasma concentrations of total chlorpheniramine and its individual enantiomers were determined with a validated chiral HPLC method and pharmacokinetic parameters were estimated using model-independent analysis. For the reference formulation, Cmax and AUC values were higher for (+)S-chlorpheniramine ((+)S-CPAM) compared to (-)R-chlorpheniramine ((-)R-CPAM) (13.3 vs. 6.8 ng/ml and 409 vs. 222 ng/ml/h, respectively) while Clt/F and Vd/F were lower (9.8 vs. 17.6 l/h and 321 vs. 627 l, respectively). No difference was observed for Tmax, t(1/2), and MRT. Pharmacokinetic parameters were similar for the reference and the Vietnamese-tested formulation. Bioequivalence was assessed by Schuirmann test, as recommended by the current FDA and European Community criteria. Dissolution tests showed that both formulations were equivalent. A nonstereospecific, but not a stereospecific, approach indicated bioequivalence between the formulations.

Adult↗
PubMed2000

Ecotoxicological evaluation of pig slurry.

Swine sewage could be source of nutrients and pollutants. This work estimates the environmental risk in nine samples from different farm treatment systems based on the evaluation of their effects in Daphnia magna acute test, and on the assessment of Cu, Zn and ammonia as main contributors. NH3 and Cu were responsible for LC50 results (1-5% of dilution). Organic compounds were quantified through several extraction methods (SPMDs, SPE and solvent extraction). A more exhaustive extraction was performed in an additional sample, which showed indole and phenol recoveries much higher than the previous ones. This method also includes PCBs (430 ppb) and fatty acids (approximately =150 ppm) quantification.

Ammonia↗