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Biomedical subjects

A Rebelo

Publications and source records attributed to A Rebelo.

12 recordsLinked to original sources
PubMed2007

Characterization and in vivo evaluation of sol-gel derived hydroxyapatite coatings on Ti6Al4V substrates.

Hydroxyapatite (HAP) based coatings on titanium alloy Ti6Al4V were attempted by sol-gel process. Precursor sol was dip-coated onto the substrates and the formation of HAP as the main phase was ensured after the sintering of coatings at 900 degrees C, as confirmed by the characterization studies involving XRD, FT-IR, Raman, and SEM-EDXS analysis. The biocompatibility of HAP-based coated titanium implants was tested by implantation studies in rabbit's tibia for a period of 8 weeks. Bone remodelling and inflammatory responses of the implants were studied during the implantation period. The better tissue-implant interaction of the coated implants with respect to the uncoated implants was observed after a defect healing period of 8 weeks. A coated implant with no evidence of rejection is a further advantage of the sol-gel derived HAP coating.

Alloys↗
PubMed2006

Novel synthesis and structural characterization of fluorine and chlorine co-substituted hydroxyapatites.

Fluorine and chlorine co-substituted hydroxyapatites (HAP) were prepared through aqueous precipitation method. Characterization results from X-ray diffraction (XRD) revealed that co-substitution of these anions resulted in the formation of pure HAP phase except for the small observed difference in the lattice parameters of the resultant apatites. The elemental analysis and FT-IR results have also confirmed the incorporation of substituted anions in the apatite structure. The calculated crystallite size for all anionic substituted apatite fall well below the range of 50 nm size that tend to coincide with the value of bone mineral crystallite size.

Chemistry, Inorganic↗
PubMed2001

[Complete congenital atrioventricular block].

Congenital atrioventricular block is defined (Yater) as a documented conduction defect in a young subject with unquestionable bradycardia in the absence of a history of infection which might have caused the condition. This condition may be isolated or associated with structural cardiac disease. Isolated block is often observed in patients with mothers suffering from autoimmune disease, often clinically latent. Anti-Ro/SS-A and La/SS-B antibodies cross into the fetal circulation and cause inflammation of the fetal conduction system. The diagnosis of the conduction defect is sometimes made during fetal life by echocardiography. Echocardiography assesses fetal hemodynamic status and may detect signs of fetal deterioration. Long-term follow-up studies have revised the previously considered good prognosis of isolated congenital atrioventricular block but advances in cardiac pacing provide satisfactory treatment. Follow-up by Holter monitoring, exercise testing and echocardiography is justified in children and adolescents; the patients may become symptomatic at any age. Indications for permanent pacing in pediatric patients have been difficult to determine due to the lack of data from controlled studies and multicenter trials. Pacing is not always easy in children. Epicardial pacing is advocated in small patients (< 5 years of age or 30 kg in weight). A pacing mode which restores the normal atrioventricular sequence is theoretically superior to single ventricular pacing even with rate responsive frequency.

Adolescent↗
PubMed1999

Acute gastrointestinal effects of graded levels of copper in drinking water.

The objective of this study was to determine the acute gastrointestinal effects caused by the consumption of drinking water containing graded levels of added copper. Sixty healthy, adult women were randomly assigned to receive copper [Cu(II)] at four concentrations in their drinking water following a Latin-square design. Each group (n = 15) received tap water with no added copper, 1, 3, and 5 mg Cu/l of added copper sulfate for a 2-week study period, followed by 1 week of standard tap water. The subjects recorded their water consumption and gastrointestinal symptoms daily on a special form. The average daily consumption of water was 1.64 liters per subject, regardless of the amount of copper added. Final serum copper, ceruloplasmin, and liver enzymes were measured in all subjects and were not different from baseline concentrations. Twenty-one subjects (35%) recorded gastrointestinal disturbances sometime during the study, 9 had diarrhea, some with abdominal pain and vomiting, and 12 subjects presented abdominal pain, nausea, or vomiting. There was no association between copper levels in drinking water and diarrhea. However, nausea, abdominal pain, or vomiting were significantly related to copper concentrations in water. The recorded incidence rate of these symptoms was 5, 2, 17, and 15% while ingesting water with 0, 1, 3, and 5 mg Cu/l, respectively (overall [chi]2 = 11.3, p<0.01; Cu [less than/equal to]1 mg/l versus Cu [Greater than/equal to]3 mg/l, [chi]2, p<0.01). When subjects interrupted their consumption of drinking water with added copper, most symptoms disappeared. We conclude that under the conditions of the study, there was no association between aggregate copper in drinking water within the range of 0-5 mg/l and diarrhea, but a [Greater than/equal to]3 mg Cu/l level of ionized copper was associated with nausea, abdominal pain, or vomiting. Additional studies with sufficient numbers of subjects are needed to define thresholds for specific gastrointestinal symptoms with precision and to extrapolate these results to the population at large.

Adult↗
PubMed1982

A case of acute poisoning by methyl demeton in a female 5 months pregnant.

During the last decade the number of poisonings by pesticides in Portugal has been steadily rising. Out of 140 patients treated in our Intensive Care Unit (I.C.U.), 86 were male and 54 were female, one of whom was 5 months pregnant. Besides all the care and surveillance required by every case of acute poisoning, pregnant females raise particular problems. Four months later, she gave birth to a normal child. Its follow-up has shown a normal morpho-physiological and psycho-motor development.

Adult↗
PubMedDate not supplied

[Acute eosinophilic pneumonia associated with acute respiratory distress syndrome: case report].

The Authors present a case of acute eosinophilic pneumonia (AEP) associated with severe acute respiratory distress syndrome in a previously healthy young adult, medicated with nitrofurantoin. AEP must be included in the differential diagnosis of community adquired pneumonia, as well as a cause of acute respiratory distress syndrome; its diagnosis is suggested by the presence of eosinophilic alveolitis in bronchoalveolar lavage fluid. The early diagnosis of AEP and corticosteroid therapy may be lifesaving.

Acute Disease↗