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Biomedical subjects

M Gaspar

Publications and source records attributed to M Gaspar.

At least 19 recordsLinked to original sources
PubMed2005

Effects of infauna harvesting on tidal flats of a coastal lagoon (Ria Formosa, Portugal): implications on phosphorus dynamics.

The systematic collection of benthic organisms in tidal flats of coastal lagoons should be taken into account for the management of these systems, once sediment disturbance affects biogeochemical processes by favouring pore water renewal during tidal inundation. The objective of the present work was to evaluate the effects of infauna harvesting on the phosphorus dynamics of muddy and sandy intertidal areas in the Ria Formosa. Sediment cores and overlying water were collected during August 2000 and February 2001 from reworked and undisturbed sediment before and after flooding. Results obtained showed that during the first minutes of flooding there was a marked decrease of phosphate in pore water of disturbed sediments. However, phosphate tidal fluxes from sandy sediment were clearly higher (17 nmol cm(-2) d(-1) in summer and 3 nmol cm(-2) d(-1) in winter) than in muddy sediment (0.4 nmol cm(-2) d(-1) in summer and -0.01 nmol cm(-2) d(-1) in winter). After muddy sediment disturbance concentrations of iron oxides increased quickly (from 5 to 16 micromol g(-1)) and phosphate was sorbed onto these iron oxides, resulting in a buffering of phosphate pore water concentrations at low values in the oxidized sediment zone. The estimated P-output from muddy sediment decreased one to two orders of magnitude after sediment disturbance in contrast to sandy sediments in which the impact of infauna harvesting was minimal. Consequently, the P-cycle is influenced by the disruption of muddy habitats in tide-driven systems. Such information could be useful for the management of the lagoon.

Animals↗
PubMed2001

Epidemiology of meningococcal meningitis in Angola, 1994-2000.

We describe six meningococcal disease outbreaks that occurred in Angola during the period 1994-2000. In total, 7140 cases were documented. The age groups most affected were 15-29 years and 5-14 years; there were no differences in incidence between the sexes. Circulation of both serogroup A and sporadic serogroup B strains was demonstrated. Mass vaccination campaigns with A+C meningococcal polysaccharide vaccine were implemented, except in Yambala province in 1999 where insecure conditions precluded this intervention. Outbreaks of serogroup A meningococcal disease in Angola may indicate an extension of these epidemics outside the meningitis belt. Mass vaccination campaigns stopped the Angolan epidemics within weeks. Civil conflict and displaced persons living in crowded areas created serious difficulties for surveillance and impeded timely public health responses.

Adolescent↗
PubMed2000

Outbreak of poliomyelitis in Angola.

Between January and June 1999, 1,100 suspected cases of poliomyelitis were reported in Angola. Poliovirus types 3 and 1 were isolated. Patients' ages ranged from 2 months to 14 years. Of the 588 patients whose vaccine status was known, 58 (9.9%) received >4 doses, 216 (36.7%) received 3 or 4 doses, 178 (30.3%) received 1 or 2 doses, and 136 (23.1%) had no history of vaccination. Civil conflict, economic decline, and crowded areas with scarce sanitation and poor water supply are the most important factors implicated in declining rates of routine vaccination, low population immunity, and intense wild poliovirus transmission. The socioeconomic situation and poor roads have created major difficulties for vaccination and surveillance. The Angolan outbreak has serious implications for the global eradication of poliomyelitis. Surveillance of acute flaccid paralysis remains essential in the assessment of strategies for eradication and interventions to interrupt wild poliovirus transmission.

Adolescent↗
PubMed1999

Molecular recognition of synthetic siderophore analogues: a study with receptor-deficient and fhu(A-B) deletion mutants of Escherichia coli.

The biological activity of six synthetic siderophore analogues (two dihydroxamates, two trihydroxamates, one tetrahydroxamate and one 3-hydroxy-4(1H)pyridinone) has been studied in Escherichia coli, Morganella morganii 13 and Proteus mirabilis 8993 strains by using growth promotion tests. Various transport-deficient mutants of E. coli were used to study the route of entry into gram-negative bacteria. The results indicated that the synthetic hydroxamate compounds are transported via Fhu-mediated transport systems, although receptor specificity was low. This could be proven by using a delta (fhuA-B) E. coli mutant as a control in which growth promotion by natural hydroxamates was completely abolished, suggesting that a periplasmic binding-protein-dependent transport system (FhuB, C, D) is required for the transport of all synthetic ferric hydroxamate complexes. Although utilization of the synthetic hydroxamates was generally lower than that of the natural siderophores, differences in growth promotion could be detected. Highest activity was observed with the dihydroxamate DOCYDHAMA ligand which supported growth at concentrations < 1 mM. In comparison with other polyamino-polyhydroxamate ligands studied, this dihydroxamate ligand has an extra diamide backbone that could be important for the interaction with the receptors or with FhuD. The synthetic trihydroxamate and tetrahydroxamate ligands showed a relatively low siderophore activity. Studies with Proteus and Morganella in the presence of increasing bipyridyl concentrations showed a decreased growth promotion with the synthetic ferric hydroxamates, suggesting the involvement of a reduction step during iron mobilization or an increased toxicity of bipyridyl. This was not observed in the case of the 3-hydroxy-4(1H)pyridinone where bipyridyl had no effect.

Bacterial Outer Membrane Proteins↗
PubMed1997

A collaborative approach to the diagnosis of a lethal short limb skeletal dysplasia.

We report a male infant with a lethal short limb Skeletal Dysplasia, born in a District Hospital in the South of Portugal. Local paediatricians investigated clinical and radiographical data. At the Perinatal Pathology Unit of the Egas Moniz hospital the diagnosis of Atelosteogenesis type II was proposed by the Clinical Geneticist and was supported by histopathological findings. Only a collaborative approach turned possible the diagnosis of this unusual entity. Atelosteogenesis type II and Diastrophic Dysplasia are closely related diseases, with similarities in phenotypic and histopathological presentation. Recently, these similarities were extended to molecular levels. The DNA analysis, in progress, will be able to establish a final diagnosis for this affected family.

Abnormalities, Multiple↗
PubMed1990

Oxygen free radicals in acute pancreatitis of the rat.

This study aimed to assess the role of oxygen free radicals in acute pancreatitis. Acute pancreatitis was induced in rats by infusion of the CCK-analogue cerulein (5 micrograms/kg per hour) for 30 minutes, 3.5 hours, and 12 hours. After the infusion, serum enzymes and conjugated tissue dienes and malondialdehyde were measured and tissue samples were subjected to electron and light microscopy. Electron microscopy after 30 minutes showed moderate intracellular alterations. After 3.5 hours of cerulein infusion interstitial oedema and intravascular margination of granulocytes in the pancreatic gland were seen. After 12 hours histological evaluation showed pronounced zymogen degranulation, extensive tissue necrosis, and migration of granulocytes into the tissue. Amylase and lipase activities increased 15 and 35-fold respectively during this time. After 30 minutes of cerulein infusion conjugated dienes and malondialdehyde increased, they reached their peak after 3.5 hours and decreased to normal values after 12 hours. Treatment with superoxide dismutase (100,000 U/kg/hour) and catalase (400,000 U/kg/hour) either before or after the start of the cerulein infusion prevented lipid peroxidation and reduced zymogen degranulation and tissue necrosis. Tissue oedema and inflammatory response, however, were not affected in any of the treated rats. Oxygen free radicals are instrumental in the development of acute pancreatitis. Even after its onset, scavenger treatment reduced the tissue damage normally observed.

Acute Disease↗
PubMed1989

The efficacy and safety of home nebulizer therapy for children with asthma.

We evaluated the efficacy and safety of nebulized beta-agonists used in the homes of 22 children with asthma. Patients served as their own controls for the comparison of asthma-related variables between periods of 12 months before and 12 months after the initiation of home nebulizer therapy. Significant reductions in the numbers of emergency department visits, hospital admissions, and short courses of prednisone therapy occurred when home nebulizer therapy was provided. The younger the patients, the more frequently improvement occurred. After the initiation of home nebulizer therapy there was no change in the severity of illness when patients presented to the emergency department or in the number of episodes of respiratory failure. Home nebulizer therapy for children with asthma appears safe and reduces the need for hospital care and short courses of prednisone therapy.

Adolescent↗
PubMed1984

Analytical methodology for assays of serum tryptophan metabolites in control subjects and newly abstinent alcoholics: preliminary investigation by liquid chromatography with amperometric detection.

A rapid, isocratic assay for the determination of all major tryptophan metabolites in serum samples from control non-alcoholic subjects, recovered alcoholics and newly abstinent alcoholics is described. The sample preparation involves only precipitation of protein with sulfosalicylic acid. The complete liquid chromatographic analysis is short (25 min) and the sensitivity of amperometric detection permits the routine assessment of catabolites at the picogram level. This preliminary longitudinal study of the basal and post-tryptophan load serum metabolites revealed a considerable scatter of experimental results for kynurenine and serotonin in all groups examined, probably owing to the clinical heterogeneity of the sample populations.

Adult↗
PubMedDate not supplied

Epiaortic ultrasound and intraoperative transesophageal ecocardiography for the thoracic aorta atherosclerosis assessment in patient undergoing CABG. Surgical technique modification to avoid cerebral stroke.

BACKGROUND: Cerebral complication during coronary artery bypass surgery (CABG), still occurs in spite of cardiopulmonary bypass (CPB) technology advances. Our study sought to assess the role of epiaortic ultrasound (EAS) and intraoperative transesophagial ecocardiography (TEE) in detection of patients with atherosclerosis of the thoracic aorta and high risk for cerebral embolisation. Consequently our surgical strategies modification for a better cerebral protection. METHODS: Our lot study comprise 352 patients undergoing EAS and TEE, during CABG. EAS was performed before opening of the pericardium using a 7.5 MHz ultrasonic probe packed in a sterile bag. In the presence of moderate aortic atherosclerosis (maximum aortic wall thickness of 3 mm) primarily single aortic cross-clamping and choose of aortic cannulation place was carried out. In cases of severe aortic atheroma (maximum aortic wall thickness > 5 mm or mobile plaque), aortic no touch technique, off-pump were used. From 34 patients with severe ascending aortic atherosclerosis 22 of these patients (18 male, 4 female, age 72(57-79), Parsonet Score 11(0-8), Euroscore 8(2-13), McSPI Stroke Risk Index 6 (1-30%) were managed on "no touch technique", Off-pump. All patients received at least one left internal mammary artery (LIMA) in situ graft and additional extraanatomical bypass conduits: venous Y-graft from IMA (n = 14), arterial Y-graft from LIMA (n = 3), vein graft from axillary artery (n = 3), vein graft from the RIMA stump (n = 3). Median operative time was 240 (115-435) min. RESULTS: We found a mild aortic atherosclerosis in 151 patients (43%), moderate in 167 (47%) and severe in 34 patients (8.8%).. Operative mortality was 2/22 in a group with high risk index, from another cause than cerebral stroke. No cerebral stroke occurred. The rate of perioperative myocardial infarction (CKMB > 50U/l) was 5/22. Median stay in ICU, 54 hours (15-1245 hours). After a median follow up period of 8 months one death occurred from cerebral stroke and no myocardial infarction. CONCLUSION: Accurate detection of atheroma on ascending aorta and aortic arch by a combination between EAS and TEE and in special surgical technique modification using off-pump revascularization and extraanatomical bypass for the management of a heavily calcified aorta can result in a very low stroke rate despite a considerable stroke risk. The hospital mortality and morbidity can be lower than predicted by Euroscore and Parsonet Score.

Aged↗