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Biomedical subjects

F Duarte

Publications and source records attributed to F Duarte.

At least 19 recordsLinked to original sources
PubMed2006

Temporal giant cell reparative granuloma: a reappraisal of pathology and imaging features.

We report a case of large temporal giant cell reparative granuloma in a 72-year-old man. MR imaging depicted a right temporal expansile multiloculated lesion, with hyper- and hypointense signal areas on T2-weighted images, heterogeneously enhancing after gadolinium administration. Cortical thinning and bone remodeling of the temporal squamous portion were better seen on CT. The patient underwent surgery, and the diagnosis was achieved by the correlation of imaging, histologic, and laboratory findings.

Aged↗
PubMed2002

[Analysis of mutations in genes BRCA1 and BRCA2 among patients with breast and ovarian cancer in northern Portugal and Galicia].

OBJECTIVE: To detect mutations in the BRCA1 and BRCA2 genes by means of the protein truncation test (PTT) in a population in northern Portugal and Galicia with breast and ovarian cancer. DESIGN: Prospective study. SETTING: Patients in northern Portugal and Galicia with family history of breast and/or ovarian cancer.Patients. A total of 76 women with family history of breast cancer according to the BCLC criteria (Breast Cancer Linkage Consortium) were studied at IPATIMUP. MAIN RESULTS: Five cases (6.5%) with changes in the normal sequence in genes BRCA1 and BRCA2 were identified; three of these mutations occurred in the gene BRCA1 and the other two in the gene BRCA2. Two out of the three mutations found in the gene BRCA1 were de novo mutations. Changes detected in the normal sequence in the gene BRCA2 were mutations reported for the first time among the study population, according to the information obtained through the BCIC database (Breast Cancer Information Core). CONCLUSIONS: This was the first study in detecting individuals carrying mutations in the susceptibility breast cancer genes BRCA1 and BRCA2 among the population of northern Portugal and Galicia.

Breast Neoplasms↗
PubMed2001

Idiopathic spinal cord herniation: case report and literature review.

We report one case of spontaneous thoracic spinal cord herniation presenting with a progressive spastic paraparesis for 4 years in a 55 years old man. From preoperative MRI, showing a ventrally displaced atrophic spinal cord at T2-T3 level, a dorsal intradural arachnoid cyst was suspected. At operation, after a 3 level laminectomy, no arachnoid cyst was found and spinal cord herniation into a meningeal diverticulum was confirmed. The herniated myelon was replaced intradurally and the lumen of the diverticulum was filled with Teflon settled with fibrin glue to prevent recurrence. Postoperatively some neurological recovery was achieved. The literature was reviewed, regarding clinical and epidemiological features, proposed pathophysiological mechanisms, treatment options and outcome. Only 32 surgically proved cases of thoracic spinal cord herniation with no past history of spine trauma, injury or surgery were found.

Hernia↗
PubMed2000

Intra-sellar salivary gland-like pleomorphic adenoma arising within the wall of a Rathke's cleft cyst.

Salivary gland rests occur in the posterior lobe of the pituitary gland near or often communicating with the Rathke's cleft or its cystic subdivisions, and are usually incidental autopsy findings. They are attributed to the oropharyngeal development of the Rathke's pouch and may rarely give rise to salivary gland-like tumors in the sella. We present a pleomorphic adenoma, a rare tumor of the sellar region, that has not been previously recognized in association with Rathke's cleft cyst. It occurred in a 44-year-old man who presented with hypopituitarism and reduced vision. Magnetic resonance imaging showed a sellar mass with suprasellar extension which was totally removed. It consisted of segments of a cyst wall lined by focally ciliated columnar of cuboid epithelium containing goblet cells. An eosinophilic granular material with cholesterol clefts represented the contents of the cyst. Within its wall there was a tumor with ductal structures and non-ductal varied cellular components including hypercellular areas of spindle and ovoid cells forming interlacing fascicles. Individual cells appeared to float in abundant mucinous material. The appearances were those of a salivary gland pleomorphic adenoma arising within the wall of a Rathke's cleft cyst. The myoepithelial nature of non-ductal tumor cells was confirmed with immunocytochemistry. The existence of seromucous glands communicating with the Rathke's cleft remnants, explains the concomitant occurrence of the tumor and the cyst. This rare neoplasm from salivary gland rest should be considered in the differential diagnosis of unusual sellar and suprasellar tumors.

Actins↗
PubMed2000

[Multiple sclerosis, spinal cord ependymoma and intracranial meningioma: case report].

We report the association a multiple sclerosis (MS), spinal cord tumour and intracranial tumor in a 63 years-old female patient with a 10 years history of relapsing/remitting MS. Symptoms usually remitted in response to costicosteroid therapy. In 1997 the patient presented with paraparesis and paresis of right arm which did not respond to corticotherapy. A spinal RMI revealed in the cervical spinal an intra spinal cord tumour, further diagnosed as ependymoma, and a parietal region meningioma. We call attention to this rare association of central nervous system tumour and MS, enphasizing the need for investigation of new and uncommon symptoms during the evolution of MS.

Brain Neoplasms↗
PubMed1999

Novel aromatic inhibitors of influenza virus neuraminidase make selective interactions with conserved residues and water molecules in the active site.

The active site of type A or B influenza virus neuraminidase is composed of 11 conserved residues that directly interact with the substrate, sialic acid. An aromatic benzene ring has been used to replace the pyranose of sialic acid in our design of novel neuraminidase inhibitors. A bis(hydroxymethyl)pyrrolidinone ring was constructed in place of the N-acetyl group on the sialic acid. The hydroxymethyl groups replace two active site water molecules, which resulted in the high affinity of the nanomolar inhibitors. However, these inhibitors have greater potency for type A influenza virus than for type B influenza virus. To resolve the differences, we determined the X-ray crystal structure of three benzoic acid substituted inhibitors bound to the active site of B/Lee/40 neuraminidase. The investigation of a hydrophobic aliphatic group and a hydrophilic guanidino group on the aromatic inhibitors shows changes in the interaction with the active site residue Glu275. The results provide an explanation for the difference in efficacy of these inhibitors against types A and B viruses, even though the 11 active site residues of the neuraminidase are conserved.

Benzoic Acid↗
PubMed1999

Potent inhibition of influenza sialidase by a benzoic acid containing a 2-pyrrolidinone substituent.

On the basis of the lead compound 4-(N-acetylamino)-3-guanidinobenzoic acid (BANA 113), which inhibits influenza A sialidase with a Ki of 2.5 microM, several novel aromatic inhibitors of influenza sialidases were designed. In this study the N-acetyl group of BANA 113 was replaced with a 2-pyrrolidinone ring, which was designed in part to offer opportunities for introduction of spatially directed side chains that could potentially interact with the 4-, 5-, and/or 6-subsites of sialidase. While the parent structure 1-(4-carboxy-2-guanidinophenyl)pyrrolidin-2-one (8) was only a modest inhibitor of sialidase, the introduction of a hydroxymethyl or bis(hydroxymethyl) substituent at the C5' position of the 2-pyrrolidinone ring resulted in inhibitors (9 and 12, respectively) with low micromolar activity. Crystal structures of these inhibitors in complex with sialidase demonstrated that the substituents at the 5'-position of the 2-pyrrolidinone ring interact in the 4- and/or 5-subsites of the enzyme. Replacement of the guanidine in 12 with a hydrophobic 3-pentylamino group resulted in a large enhancement in binding to produce an inhibitor (14) with an IC50 of about 50 nM against influenza A sialidase, although the inhibition of influenza B sialidase was 2000-fold less. This represents the first reported example of a simple, achiral benzoic acid with potent (low nanomolar) activity as an inhibitor of influenza sialidase.

Benzoates↗
PubMed1999

Hydrophobic benzoic acids as inhibitors of influenza neuraminidase.

Neuraminidase (NA) plays a critical role in the life cycle of influenza virus and is a target for new therapeutic agents. A new benzoic acid inhibitor (11) containing a lipophilic side chain at C-3 and a guanidine at C-5 was synthesized. The X-ray structure of 4-(N-acetylamino)-5-guanidino-3-(3-pentyloxy)benzoic acid in complex with NA revealed that the lipophilic side chain binds in a newly created hydrophobic pocket formed by the movement of Glu 278 to interact with Arg 226, whereas the guanidine of 11 interacts in a negatively charged pocket created by Asp 152, Glu 120 and Glu 229. Compound 11 was highly selective for type A (H2N2) influenza NA (IC50 1 microM) over type B (B/Lee/40) influenza NA (IC50 500 microM).

Antiviral Agents↗
PubMed1998

Autogenous mandibular bone grafts in the treatment of the resorbed maxillary anterior alveolar ridge: rationale and approach.

Patients can present with a variety of conditions that limit, or prevent, the ideal placement of endosteal implants. One of these situations is depicted by an insufficient amount of bone for implant placement in the maxillary anterior alveolar ridge. Autogenous bone grafting can be used to augment the ridge to provide a sufficient amount of bone for implant placement. Using the mandibular symphysis as a donor site offers ease of access, good bone quality for localized repair, a corticocancellous block graft morphology, low morbidity, and minimal graft resorption. A procedure for harvesting and placing an autogenous mandibular bone graft is presented; as are the advantages of using this location as a donor site compared with other locations.

Alveolar Bone Loss↗
PubMed1998

[Image-guided stereotaxic biopsy of central nervous system lesions].

In a series of 44 image guided stereotactic biopsy from August 1995 until March 1997, findings were as follows (frequency order). Tumors, glioblastoma was the most frequent. Primary lymphoma and other conditions associated to AIDS. Metastasis, three cases, Vasculites, two cases, Arachnoid cyst, Creutzfeldt-Jakob, cortical degeneration, inespecific calcification (one case each). The age varied from 1 to 83 years. Forty one lesions were supratentorial, two infratentorial, and one was outside the brain (dura and skull) and we used stereotaxy to localize it. There was no mortality and morbidity was 2.3%. The literature is reviewed. We conclude that this procedure is safe and highly diagnostic.

Adolescent↗
PubMed1998

[Stereotaxic brain biopsy in AIDS patients with neurological manifestations].

Prospective series showing the importance of computerized stereotactic brain biopsy in the management of AIDS patients neurologically symptomatic and confirmed by images. Patients undergone an algorithm step by step done by their own doctors and referred to us for stereotactic biopsy. Our protocol was opened in August 1995 and closed in December 1996. Twenty patients were biopsied. This protocol is similar to the Levy's one (Chicago IL, USA). We have got diagnosis in all cases. Lymphoma was predominant and followed by toxoplasmosis, progressive multifocal leukoencephalopathy and HIV encephalopathy. We included one patient with diploic giant cells lymphoma. Our mortality and morbidity was zero. By these results we conclude that stereotactic biopsy in AIDS patients is safe and effective.

AIDS Dementia Complex↗
PubMed1997

Progressive multifocal leukoencephalopathy in a child with acquired immunodeficiency syndrome (AIDS).

Progressive multifocal leukoencephalopathy is a rare viral-induced demyelinating disease associated to immunodeficiency. A 10-year-old boy with AIDS is reported, who developed subacute cerebellar signs and symptoms with multiple cranial nerve involvement and dementia. A computed tomography scan revealed a focal nonenhancing area of low attenuation in the cerebellum. On magnetic resonance imaging high signal lesions in T2 weighted sequences were shown. The biopsy of one of those lesions showed the typical histological findings of progressive multifocal leukoencephalopathy. It seems important to consider this diagnosis in children with AIDS who present with progressive neurological features.

Acquired Immunodeficiency Syndrome↗
PubMed1995

Ca(2+)-independent nitric oxide synthase activity in human lung after cardiopulmonary bypass.

BACKGROUND: Because surgery involving cardiopulmonary bypass induces a systemic inflammatory response, the effect of cardiopulmonary bypass on nitric oxide (NO) generation was investigated in human lung tissue. METHODS: Nitric oxide synthase (NOS) activity was measured by the conversion of 14C-L-arginine to 14C-L-citrulline in tissue biopsy samples obtained before and after cardiopulmonary bypass. RESULTS: The Ca(2+)-independent production of NO found before cardiopulmonary bypass was extremely low (1.5 (0.5) pmol citrulline/mg/min), but was increased after the bypass operation (23.6 (11) pmol/mg/min). CONCLUSIONS: Ca(2+)-independent NOS activity was detected in human lung after cardiopulmonary bypass. This finding may provide an important insight into the pathogenesis of the tissue damage and acute phase response observed after such surgery.

Amino Acid Oxidoreductases↗
PubMed1994

Immunochemical characterization of monoclonal IgG containing mixed cryoglobulins.

Monoclonal IgG-containing type II cryoglobulins (CG) from 25 patients, most affected with autoimmune or inflammatory diseases, were characterized using a Western blotting procedure. Rheumatoid factors were measured by ELISA. Out of the 25 type II CG, 14 contained a single monoclonal IgG and 11 contained several distinct monoclonal Ig, as assessed by the electrophoretic mobility and isotypy of the narrow bands. Comparison of blots revealed by anti-IgG subclass antibodies in the patients' sera and CG showed a clear-cut enrichment of CG in both polyclonal and monoclonal IgG1 and IgG3. All monoclonal IgG in the CG belonged to the IgG1 or IgG3 subclasses. CG also contained more detectable RF of the IgM class than did the corresponding sera. Using conventional methods, the present CG either could not be typed or were all (immunoelectrophoresis) or often (immunofixation) classified as type III. The results challenge the classical classification of CG and show the necessity of the use of sensitive techniques for immunochemical characterization of mixed CG.

Adult↗
PubMed1994

[Intracranial cavernous angioma].

Clinical, radiological and histopathological features of eight cases of symptomatic cavernous angioma are presented. Five patients were being evaluated for seizure, two for mass lesions and one for intracranial hemorrhage. CT and/or MRI detected the lesion in all cases, but there is not a characteristic image for cavernous angioma. Good results were obtained by microsurgical approach to these malformations in seven patients with only one patient suffering a worsening of neurological status after surgery.

Adolescent↗
PubMed1993

Complete variable region deletion in a mu heavy chain disease protein (ROUL). Correlation with light chain secretion.

In a patient affected with chronic lymphocytic leukemia with lymphocyte surface mu and kappa determinants and vacuolated bone marrow plasma cells, the serum contained polymers of a truncated mu chain and normal-sized kappa chains. These light chains were present as monomers and covalent dimers in studies performed under dissociating conditions, but they were linked by non-covalent bridges to a portion of the serum short mu chains. The patient's urine contained a kappa type Bence-Jones protein. Study of a messenger RNA and complementary DNA from blood cells showed the abnormal mu chain to lack the entire variable region, likely due to a direct splicing of the leader peptide exon onto the CH1 exon. The production of light chains, a rare event in heavy chain diseases, appears to correlate with the occurrence of a heavy chain deletion restricted to the variable domain, likely because the non-covalently linked light chains allow these unusual heavy chains to be secreted.

Amino Acid Sequence↗