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Biomedical subjects

J Couceiro

Publications and source records attributed to J Couceiro.

12 recordsLinked to original sources
PubMed1998

Serum carnitine levels in epileptic children before and during treatment with valproic acid, carbamazepine, and phenobarbital.

Serum levels of free, acyl, and total carnitine were determined in 32 patients with seizures, before and after 3, 6, and 12 months of treatment with valproic acid (17 patients), carbamazepine (10 patients), or phenobarbital (5 patients). In all three treated groups, both free and total carnitine levels showed a significant decline with respect to pretreatment levels. This decline was most marked and most consistent in patients treated with valproic acid. In 35% of the patients in this group, carnitine deficiency (ie, total carnitine < 30 micromol/L) was observed by month 12. In none of the three groups were serum carnitine levels significantly correlated with the serum concentration of the drug. These findings suggest a need to monitor serum carnitine levels in children treated with any of these drugs.

Adolescent↗
PubMed1993

Effects of amphetamine on influenza virus infection in mice.

Several experiments were conducted to evaluate the effects of chronic amphetamine on the influenza A (PR-8/34) virus specific immune injury in CD-1 mice. Treatment with amphetamine resulted in a significant increase of lung virus titers and pulmonary vascular permeability. Amphetamine also increased the lethality of infected mice.

Amphetamine↗
PubMed1993

Phagocytic activity in stressed mice: effects of alprazolam.

Mice exposed to a chronic auditory stressor and daily injected with alprazolam (1 mg/kg/day, s.c.) showed a reduction in stress-induced suppression of the in vitro and in vivo activity of phagocytosis, measured using the zymosan particle uptake method and the carbon clearance test, respectively. Pretreatment with Ro-15-1788 (10 mg/kg, s.c.), a central nervous system benzodiazepine antagonist, resulted in suppression of the effects of alprazolam in stressed mice.

Alprazolam↗
PubMed1991

Effects of alprazolam on T-cell immunosuppressive response to surgical stress in mice.

Mice submitted to surgical stress induced by laparotomy and treated with chronic alprazolam (1 mg/kg) showed a reduction in stress-induced suppression of thymus and spleen cellularity, as well as in peripheral T lymphocyte population. The blastic response of spleen lymphoid cells was also assessed and found to partially supress the inhibitory effect of surgery.

Adrenocorticotropic Hormone↗
PubMed1988

Treatment of acromioclavicular disruptions: trial of a simple surgical approach.

Following the Allman and the Zlotsky and Ballard classifications, 85 cases of acromioclavicular disruptions (ACD) have been treated. Types I and II have been conservatively managed, while type III was treated by a special surgical technique described in the text. Types I and II were reviewed by a questionnaire form and type III was assessed clinically and radiologically, with good results according to a score rating made for the review.

Acromioclavicular Joint↗
PubMed1987

Immunoresponses to Neisseria meningitidis epitopes: immunomodulation by meningococcus B acts on more than one meningococcal surface epitope.

Neisseria meningitidis group B strain M986 (serotypes 2a, 7) (NMB) elicits a specific primary antiphosphorylcholine immune response in mice but not a secondary response. The ability of other serotype and serogroup meningococci to induce similar primary responses in mice was studied, as was the immunogenicity of trinitrophenyl coupled NMB (TNP-NMB) in primary and secondary antitrinitrophenyl responses. Except for NMB, all other strains tested (three serogroup B and one serogroup A meningococcal strains) were found to be very poor phosphorylcholine immunogens. TNP-NMB, however, though proving to be a very good TNP antigen, was only a weak phosphorylcholine antigen. Priming NBF1 female mice with TNP-NMB one month or more before challenging them with the same antigen induced a strong depression of anti-TNP response in the subsequent challenge. However, this effect was not observed with Xid NBF1 male mice. Furthermore, priming mice with NMB weakly affected the anti-TNP response, but greatly depressed the antiphosphorylcholine response, after TNP-NMB challenge. In addition, whereas apparently only one TNP-specific B cell subpopulation was responding in unprimed mice challenged simultaneously with TNP-NMB and TNP-Ficoll (non-additive response), priming mice with NMB appeared to facilitate the independent activation of two different TNP-specific B cell subpopulations (additive response).

Animals↗
PubMed1986

Immunoresponses to Neisseria meningitidis epitopes: suppression of secondary response to phosphorylcholine is carrier specific.

Results of our previous work have shown that Neisseria meningitidis serogroup B M986 can induce a phosphorylcholine (PC)-specific plaque-forming cell immunoresponse in mice. Also, a single injection of a relatively low dose of meningococci in NBF1 female mice induced a priming time-dependent suppression on subsequent meningococcus challenge. This suppression was not due to switching to another class of immunoglobulin nor to the presence of a capsule on N. meningitidis. In this study we show that suppression induced by meningococcus is carrier specific. Furthermore, we offer evidence suggesting that the structure(s) on meningococcus that trigger this suppression is heat labile and different from the antigenic structure(s) recognized by the suppressed B cells. In addition, we found that there is a gradual increase in antibody secretion rates of N. meningitidis-induced anti-PC plaque-forming cells that correlates with N. meningitidis priming time. Rather unexpected was the fact that pretreatment of mice with PC-keyhole limpet hemocyanin (thymus-dependent antigen) had a great influence on the subsequent PC-specific immunoresponses induced by N. meningitidis and PC-coupled heat-inactivated meningococcus [PC-(NMB)HI], as shown by (i) a striking decrease in T15 idiotype expression, (ii) concomitant direct anti-PC plaque-forming cells reduction, (iii) switching to immunoglobulin G (N. meningitidis-induced immunoresponse) or immunoglobulin G plus immunoglobulin A [PC-(NMB)HI-induced immunoresponse], and (iv) a significant increase in heterogeneity of plaque-forming cell secretion rates. The possibility that N. meningitidis, PC-(NMB)HI, and PC-KLH stimulate B lymphocytes pertaining to three different subpopulations embedded in distinct regulatory circuits is discussed, with emphasis on the interrelationships between T-dependent and T-independent lymphocyte compartments. We focus on the possibility of the existence of high-level regulatory circuits in which lymphocyte subpopulations or sets of lymphocyte subpopulations with different requirements of activation are connected.

Animals↗
PubMed1986

Effects of antigen and internal environment on anti-phosphorylcholine immune responses of autoimmune aged NZB/W F1 mice.

The idiotypic profile of anti-phosphorylcholine plaque-forming cell responses and their evolution with ageing were studied in (NZB X NZW) F1 mice. Our results showed that the anti-phosphorylcholine plaque-forming cell response induced by phosphorylcholine coupled to keyhole limpet haemocyanin and, paralleling, the T15 idiotype clonal dominance declined with ageing. This loss of immune competence was also observed with another thymus-dependent (phosphorylcholine coupled to egg globulin) as well as thymus-independent (capsular polysaccharide of Streptococcus pneumoniae strain R36a) antigens. In contrast, old mice challenged with an antigenic preparation of Neisseria meningitidis showed an immune response not significantly different from that elicited by the same antigen in young mice. The hapten-augmentable plaque-forming cells were assayed to determine whether a putative auto-antiidiotypic regulation underlies this loss of immune competence. Only minimal numbers and non-significant differences between young and old mice immunized with any antigen could be detected. Further studies using an adoptive transfer system demonstrated that cells from aged mice were able to support a normal anti-phosphorylcholine response when transferred into lethally irradiated young recipients. Our results suggest that no permanent cellular defects, but rather internal environment or/and radioresistant suppressor cells, are involved in this loss of immune competence. The role played by these factors and their effect on distinct subpopulations of B cells are discussed.

Aging↗
PubMedDate not supplied

Cerebral oxygenation in children with syncope during head-upright tilt test.

The pathophysiology of neurocardiogenic syncope remains incompletely known. In this entity, besides abnormal systemic hemodynamic regulation, potential cerebral circulatory abnormalities have been reported. In this setting, cerebral saturation assessment could detect cerebral blood flow changes and estimate the sufficiency of brain oxygenation during the event. A head-upright tilt test was performed in 25 children aged between 6 and 16 years. In addition to the standard protocol, cerebral oxygen saturation was determined noninvasively by means of a near-infrared spectrophotometry device. In the 19 children with a positive tilt test, significant impairment of cerebral saturation was detected both at the start of the patient's complaints (without hemodynamic modifications) and during syncope. Our results support the hypothesis of the presence of abnormal cerebral hemodynamic autoregulation in children with neurocardiogenic syncope.

Adolescent↗
PubMedDate not supplied

A Markov random field model for bony tissue classification.

3D biomedical images are a valuable source of information for clinical diagnosis. In areas such as bone remodeling, fracture prediction and prosthesis design, the external geometry of the bones needs to be precisely defined and injuries identified. A system that automatically interprets and presents a 3D reconstruction of the bone can be very useful, although this task cannot be carried out without specific knowledge of the domain. This knowledge may be represented by a set of constraints over properties and relationships between regions. In this work we present a Markov random field model for identification of injuries in the proximal tibia.

Bone and Bones↗