Biomedical subjects

Cristina Ribeiro

Publications and source records attributed to Cristina Ribeiro.

7 recordsLinked to original sources

PubMed2006

[Diabetes in the elderly: our reality].

AIM: To evaluate the impact of the aging of our population in the growing of diabetes prevalence, among patients treated inward at our department. MATERIAL AND METHODS: The clinical files of 242 diabetics older than eighty years, treated between 1999 and 2002 were studied retrospectively. Demographic (sex, age, year of first contact), clinical (causes of admission, co-morbidities, duration of diabetes, previous hypoglycaemic treatment, duration of hospitalisation and evolution) and biochemical (glycaemia, HbA1c, lipaemia and C-peptide) data were recorded. RESULTS: A progressive rising in the number of aged patients was found during this period (seven in 1999 to 55 in 2002), with a large proportion of women (73%). The more frequent causes of in-hospital treatment were hyperglycaemia (20.6%) and feet ulcers (septic or necrotic) (16.5%). In nearly 42% of the cohort an acute infection was found. Diabetes was unknown in 13% of cases and less than ten years of duration in 38%. In this cohort most of the patients (77%) were treated with oral hypoglycaemic drugs, mostly sulfonylureas. HbA1c mean value was 10.4 +/- 2.2%; C -peptide was measured in a subset of cases (n=79), suggesting deficient insulin secretion in 18% of them. The global mean duration of hospitalisation was eleven days. Nineteen patients (8%) died during the hospitalization. CONCLUSIONS: In this study, we concluded that diabetes in people older than 75 years, is being progressively more often diagnosed. The general metabolic control was bad (HbA1c mean value--10.4 +/- 2.2%), with a significant number of patients presenting a deficient C-peptide secretion, worsened by frequent coexisting infections. So, a strengthened clinical care, directed to a careful diagnosis and treatment, may effectively contribute to a better prognosis and quality of life of aged diabetic patients.

Aged, 80 and over↗

PubMed2005

CYP2D6 genetic polymorphisms are associated with susceptibility to pituitary tumors.

Several polymorphisms of drug-metabolizing enzymes have been implicated in the susceptibility to tumor development. The role of the CYP2D6, GSTM1 and GSTT1 genes has been extensively studied, with alleles conferring different metabolic efficiencies and tumor risk. We studied the relationship between the main polymorphisms of these genes and the susceptibility to develop pituitary tumors, by performing a case-control study comprising 235 patients and 256 controls which were genotyped by means of PCR-RFLP based assays. Frequencies of the CYP2D6*1 and of the poor metabolizer allele CYP2D6*4, were determined along with the frequencies of the GSTM1 and GSTT1 null genotypes. CYP2D6 genotype frequencies were similar in patients and controls (p=0.087). CYP2D6*1 and CYP2D6*4 allele frequencies were 83.8%, 16.2% in cases and 78.3%, 21.7% in controls, showing a significant difference between the two groups (p=0.012). There were no significant differences between the frequencies of the GSTM1 and GSTT1 null genotypes in both groups. No association was found between histological type and any of the studied polymorphisms. Our data suggest an association of the CYP2D6*1 allele and the susceptibility to pituitary adenomas, which could be due to an increased metabolism of unidentified procarcinogens or to linkage disequilibrium with another gene involved in pituitary tumorigenesis.

Adenoma↗

PubMed2005

[Pharmacological therapy of Cushing's disease].

The curative treatment of Cushing's disease is surgery, mainly transphenoidal surgery. The cure probability is high and the risks or complications are few. However, pharmacotherapy is necessary while localisation of the secreting tumour is not achieved, when there is persistence of hypercortisolism after surgery, or while waiting for effectiveness of radiotherapy. We review the existing drugs, their characteristics, mechanisms of action, doses and specific indications.

Humans↗

PubMed2005

MamMiBase: a mitochondrial genome database for mammalian phylogenetic studies.

UNLABELLED: MamMiBase, the mammalian mitochondrial genome database, is a relational database of complete mitochondrial genome sequences of mammalian species. The database is useful for phylogenetic analysis, since it allows a ready retrieval of nucleotide and aminoacid individual alignments, in three different formats (NEXUS for PAUP program, for MEGA program and for PHYLIP program) of the 13 protein coding mitochondrial genes. The user may download the sequences that are useful for him/her based on their parameters values, such as sequence length, p-distances, base content, transition transversion ratio, gamma, which are also given by MamMiBase. A simple phylogenetic tree (neighbor-joining tree with Jukes Cantor distance) is also available for download, useful for parameter calculations and other simple tasks. AVAILABILITY: MamMiBase is available at http://www.mammibase.lncc.br

Chromosome Mapping↗

PubMed2004

[ACTH-dependent Cushing's syndrome: a revision of 43 cases].

AIM: To evaluate the characteristics and outcomes of the patients diagnosed as ACTH-dependent Cushing syndrome, registered in the department. MATERIAL AND METHODS: We reviewed the files of forty-three patients followed from 1974 to 2002. RESULTS: A progressive rise in the number of patients diagnosed was found, being 80% females. Clinical suspicion was based mostly on the typical fat distribution; hirsutism and amenorrhoea were important in women. The more reliable diagnostic tests were: 11 pm cortisol, day curve of ACTH and cortisol, and dexamethasone suppression tests. The ACTH response to CRH during inferior petrosal sinus sampling permitted the diagnosis of ectopic source. In thirty-seven patients a pituitary adenoma was diagnosed. The three patients diagnosed before 1985 went for bilateral adrenalectomy (Nelson's syndrome in two); the others were submitted to transsphenoidal pituitary adenomectomy, obtaining remission in twenty six at the first operation and in two others at the second. Three patients had a recidive. Of the six patients with persistent disease (all treated with metyrapone or ketoconazole), three were submitted to radiotherapy, two to bilateral adrenalectomy, and one was waiting for surgery. Four patients had a bronchial carcinoid, successfully removed in three. One patient was lost to follow-up and another was still being evaluated. CONCLUSIONS: We found a positive evolution in the capacity to diagnose and treat these patients. Neurosurgical ability to achieve remission was 80% in the operated cases. More effective technical methods and drugs, as well as a multidisciplinary and dedicated medical team, lead to long lasting remissions in most of the patients.

Adolescent↗

PubMed2003

[Autoimmune hypophysitis or lymphocytic hypophysitis].

This entity, due to the pituitary lymphoplasmacytic infiltrate, was described for the first time in 1962. The clinical suspicion relies on a rapidly progressing hypopituitarism, particularly with adrenal involvement, affecting women in the peripartum period or patients with previously recognized autoimmune disease. Diabetes insipidus is also often reported. A sellar mass is found in 80% of cases. The diagnosis is confirmed by histology, due to the absence of a specific serological test. The endocrine deficiencies are frequently definitive. Corticotherapy is usually effective in reducing neurological symptoms due to pituitary enlargement, and frequently allows to avoid surgery. The disease-related deaths were due to acute adrenal insufficiency or ineffectively treated hypopituitarism. We are reporting a clinical case of probable lymphocytic hypophysitis in the early post partum of a woman with depression and Graves disease. She has hyperprolactinemia and ACTH deficiency, without pituitary changes in the magnetic resonance imaging. She was treated and her depression and hyperthyroidism were relieved. Hyperprolactinemia recovered spontaneously but she still needs glucocorticoid substitution.

Adult↗

PubMed2002

Soluble silk-like organic matrix in the nacreous layer of the bivalve Pinctada maxima.

Nacre organic matrix has been conventionally classified as both 'water-soluble' and 'water-insoluble', based on its solubility in aqueous solutions after decalcification with acid or EDTA. Some characteristics (aspartic acid-rich, silk-fibroin-like content) were specifically attributed to either one or the other. The comparative study on the technique of extraction (extraction with water alone vs. demineralization with EDTA) presented here, seems to reveal that this generally accepted classification may need to be reconsidered. Actually, the nondecalcified soluble organic matrix, extracted in ultra-pure water, displays many of the characteristics of what until now has been called 'insoluble matrix'. We present the results obtained on this extract and on a conventional EDTA-soluble matrix, with various characterization methods: fractionation by size-exclusion and anion-exchange HPLC, amino acid analysis, glycosaminoglycan and calcium quantification, SDS/PAGE and FTIR spectroscopy. We propose that the model for the interlamellar matrix sheets of nacre given by Nakahara [In: Biomineralization and Biological Metal Accumulation, Westbroek, P. & deJong, E.W., eds, (1983) pp. 225-230. Reidel, Dordrecht, Holland] and Weiner and Traub [Phil. Trans. R. Soc. Lond. B (1984) 304, 425-434] may no longer be valid. The most recent model, proposed by Levi-Kalisman et al. [J. Struct. Biol. (2001) 135, 8-17], seemed to be more in accordance with our findings.

Amino Acids↗