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Biomedical subjects

A G Ferreira

Publications and source records attributed to A G Ferreira.

At least 19 recordsLinked to original sources
PubMed2006

In vitro regeneration of Didymopanax morototoni.

The present study aimed at establishing a complete plant regeneration protocol for Didymopanax morototoni (matchwood), a native Brazilian forest species. Four types of explants (root, shoot, node, and cotyledonary leaves) were obtained from in vitro germinated seeds. In the first step, woody plant medium (WPM) with casein hydrolysate (250 mgL-1 ) and 2,4-D (1.0 and 5.0 mgL-1) were used combined with kinetin (0.1 and 1.0 mgL-1). Twenty days after inoculation, the material was evaluated. Embryogenic calli were split, transferred to expression medium with several combinations of NAA and KIN, and moved to fresh medium after 60 days. Light did not interfere in embryo expression. Somatic embryos were formed either from individual cells or cell clusters. Plantlets were obtained in WPM medium and 10 gL-1 of sucrose with no plant regulator, or using 0.1 mgL-1 BAP and 0.5 mgL-1GA. Plantlets from somatic embryos of D. morototoni developed in 33% of the cases.

Araliaceae↗
PubMed2005

Temporal and spatial variation on heavy metal concentrations in the oyster Ostrea equestris on the northern coast of Rio De Janeiro State, Brazil.

Heavy metal (Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) concentrations were determined by ICP-AES in Ostrea equestris from three beaches (Barra do Furado, Buena, and Ponta do Retiro) on the northern coast of Rio de Janeiro State. The average concentration was 0.8 +/- 0.18, 0.4 +/- 0.21, 58 +/- 25.6, 249 +/- 52.3, 11 +/- 1.31, 0.55 +/- 0.16, 0.13 +/- 0.11, and 1131 +/- 321 microg x g(-1) dry weight for Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Zn respectively. Significant spatial variation (p < 0.05) between the samples areas occurred for Cr, Pb, and Zn with higher values in Barra do Furado; and for Cu in Ponta do Retiro. Significant temporal variations (p < 0.05) were observed for all metals except Cu. Temporal variability may be related to changes in the inputs of metals associated with suspended particles. Concentrations were similar to those found in areas under low pollution impact, except for Zn, the high concentrations of which probably reflect the physiological characteristics of these organisms.

Animals↗
PubMed2003

Synthesis of metal-oxide matrix with embedded nickel nanoparticles by a bottom-up chemical process.

Here we describe a new chemical route for obtaining highly dispersed nanometric Ni particles embedded in different matrices based on Al2O3, MgO, and TiO2 and in the heterogeneous matrices CeO2-doped Al2O3 and MgO-doped Al2O3. The synthesis method is based on a modification of the polymeric precursor method. The Ni nanoparticles (particles in the range of 1-40 nm) were obtained in a single process, without the use of an external reducing agent (hydrogen atmosphere).

Aluminum Oxide↗
PubMed2001

Distinct effects of auxin and light on adventitious root development in Eucalyptus saligna and Eucalyptus globulus.

Adventitious rooting is essential for vegetative propagation of woody species. We studied the effects of auxin and light on the development of adventitious roots in cuttings obtained from seedlings of Eucalyptus saligna Smith and E. globulus Labill in an attempt to characterize the adventitious rooting process and identify factors controlling rhizogenesis. Root development was scored as rooting percentage, root density (roots per rooted cutting), mean rooting time and root length. In both species, rooting time was reduced in the presence of auxin. Cuttings from 2-month-old E. saligna seedlings were responsive to lower auxin concentrations than comparable cuttings from E. globulus seedlings. Cuttings from 3-month-old E. saligna seedlings rooted promptly and rooting was not significantly affected by light conditions. In contrast, rooting of cuttings from 3-month-old E. globulus seedlings exhibited recalcitrant behavior and no roots were formed if illuminated during the root formation phase. Effective root regeneration of E. globulus cuttings was obtained by a 4-day exposure to 10 mg l(-1) IBA and culture in darkness during the root formation step. Loss of rooting capacity with seedling age was more pronounced in E. globulus than in E. saligna. The possibility of switching adventitious rooting off and on by manipulating light regime and exogenous auxin supply in E. globulus, and the constitutive nature of rooting in E. saligna may provide useful models for examining the rooting process at the biochemical and molecular levels in Eucalyptus.

Eucalyptus↗
PubMed2001

Evaluation of recombinant Leptospira antigen-based enzyme-linked immunosorbent assays for the serodiagnosis of leptospirosis.

There is an urgent need for development of new serodiagnostic strategies for leptospirosis, an emerging zoonosis with worldwide distribution. We have evaluated the diagnostic utility of five recombinant antigens in enzyme-linked immunosorbent assays (ELISAs) for serodiagnosis of leptospirosis. Sera from 50 healthy residents of a high-incidence region were used to determine cutoff values for 96% specificity. In paired sera from 50 cases of leptospirosis confirmed by the microscopic agglutination test, immunoglobulin G (IgG) but not IgM reacted with the recombinant leptospiral proteins. The recombinant LipL32 IgG ELISA had the highest sensitivities in the acute (56%) and convalescent (94%) phases of leptospirosis. ELISAs based on recombinant OmpL1, LipL41, and Hsp58 had sensitivities of 16, 24, and 18% during the acute phase and 72, 44, and 32% during convalescence, respectively. Compared to sera from healthy individuals, patient sera did not react significantly with recombinant LipL36 (P > 0.05). Recombinant LipL32 IgG ELISA demonstrated 95% specificity among 100 healthy individuals, and specificities ranging from 90 to 97% among 30 dengue patients, 30 hepatitis patients, and 16 patients with diseases initially thought to be leptospirosis. Among 39 Venereal Disease Research Laboratory test-positive individuals and 30 Lyme disease patients, 13 and 23% of sera, respectively, reacted positively with the rLipL32 antigen. These findings indicate that rLipL32 may be an useful antigen for the serodiagnosis of leptospirosis.

Antibodies, Bacterial↗
PubMed2001

Serodiagnosis of chronic Chagas infection by using EIE-Recombinant-Chagas-Biomanguinhos kit.

A kit based on an enzyme immunoassay, EIE-Recombinant-Chagas-Biomanguinhos, developed by the Oswaldo Cruz Foundation, was evaluated for the serodiagnosis of chronic Chagas disease. Evaluation was performed with 368 serum samples collected from individuals living in an endemic area for Chagas disease: 131 patients in the chronic phase with confirmed clinical, epidemiological, and serological diagnosis (indirect immunofluorescence, indirect hemagglutination or enzyme-linked immunosorbent assay) and 237 nonchagasic seronegative individuals were considered negative control. The EIE-Recombinant-Chagas-Biomanguinhos kit showed high sensitivity, 100% (CI 95%: 96.4-100%) and high specificity, 100% (CI 95%: 98-100%). The data obtained were in full agreement with clinical and conventional serology data. In addition, no cross-reaction was observed with sera from patients with cutaneous (n=14) and visceral (n=3) leishmaniasis. However, when these sera were tested by conventional serological assays for Chagas disease, cross-reactions were detected in 14.3% and 33.3% of the patients with cutaneous and visceral leishmaniasis, respectively. No cross-reactions were observed when sera from nonchagasic seronegative patients bearing other infectious disease (syphilis, n=8; HTLV, n=8; HCV, n=7 and HBV, n=12) were tested. In addition, sera of patients with inconclusive results for Chagas disease by conventional serology showed results in agreement with clinical evaluation, when tested by the kit. These results are relevant and indicate that the referred kit provides a safe immunodiagnosis of Chagas disease and could be used in blood bank screening.

Adolescent↗
PubMed2000

A limonoid from Trichilia estipulata.

The limonoid 21,24,25,26,27-pentanor-15,22-oxo-7alpha,23-dihydroxy-apotirucalla(eupha)-1-en-3-one was isolated from the dichloromethane extract of the stem bark of Trichilia estipulata. Its structure was established by spectroscopic methods (UV, EIMS, 1H and 13C NMR, HMQC and HMBC).

Limonins↗
PubMed2000

Arenosclerins A-C and haliclonacyclamine E, new tetracyclic alkaloids from a Brazilian endemic Haplosclerid sponge Arenosclera brasiliensis.

Arenosclerins A (2), B (3), and C (4), as well as haliclonacyclamine E (1), are new tetracyclic alkylpiperidine alkaloids isolated from a new species of marine sponge belonging to the order Haplosclerida, Arenosclera brasiliensis, a species endemic to the southeastern Brazilian coast. The alkaloids were isolated as their hydrochloride salts and identified by analysis of spectroscopic data. Data obtained from (1)H-(1)H COSY, HMBC, and HSQC-TOCSY NMR experiments allowed complete assignment of the (1)H and (13)C resonances, and analysis of the NOESY and ROESY spectra showed that the only differences between 2, 3, and 4 were the relative stereochemistries of the bispiperidine ring system. Arenosclerins A-C are the first haliclonacyclamine/halicyclamine-related alkaloids with a hydroxy group in the bridging alkyl chain.

Alkaloids↗
PubMed1999

Detection of cardiovascular abnormalities in the nursery of a general hospital in the Amazon region: correlation with potential risk factors.

Congenital heart diseases have been studied much more extensively in children than in neonates. In this study, we report on the findings from 57 neonates seen from June of 1995 through June 1996 in the nursery of a large public hospital in Belém, Pará, Brazil. All were routinely examined by a paediatrician just after birth, and, when indicated, these babies were referred to the cardiology unit of our Hospital for assessment by a paediatric cardiologist. Most of the diagnoses were made by means of Doppler and cross-sectional echocardiography with color flow mapping. Several abnormalities of the cardiovascular system were diagnosed. The most frequent was patency of the arterial duct. But, since many ducts closed spontaneously, ventricular septal defect was the most frequent lesion seen even in the nursery. Four defects (patent arterial duct, ventricular septal defect, atrial septal defect and pulmonary stenosis) together accounted for two thirds of all cardiac abnormalities. Associated non-cardiac anomalies were more frequent in those with simple lesions within the heart. All the babies with complex heart disease, and the majority of those designated as having significant lesions, died before they could be discharged. Several risk factors were investigated. Among maternal drugs, misoprostol emerged as having a possible teratogenic effect.

Brazil↗
PubMed1999

Left ventricular pseudoaneurysm complicating infective pericarditis.

Cross sectional echocardiography demonstrated a pseudoaneurysm of the left ventricular posterolateral wall close to the atrioventricular junction in a 4 year old girl with infective pericarditis complicating lobar pneumonia. Colour flow Doppler demonstrated bidirectional flow across the communication hole. Surgical resection was successful.

Aneurysm, False↗
PubMed1999

Distribution of cytoskeletal structures and organelles of the host cell during evolution of the intracellular parasitism by Trypanosoma cruzi.

The distribution of microtubules, microfilaments, mitochondria, Golgi complex and endosomes/lysosomes was analyzed in Vero cells allowed to interact for different periods of time with the pathogenic protozoan Trypanosoma cruzi and observed by confocal laser scanning microscopy. Microtubules were revealed using a mouse monoclonal anti-alpha-tubulin antibody. Actin filaments were revealed using phalloidin-rhodamine. To identify mitochondria, endosomes/lysosomes and the Golgi complex the cells were labelled with Rhodamine 123, Lucifer yellow and C6-NBD-ceramide, respectively. During cell invasion actin filaments concentrate at the site of parasite penetration in some, but not in all cells, probably depending upon the mechanism used by the trypomastigote form to penetrate into the host cells. Following internalization the trypomastigote form gradually changes into the amastigote form, disruption of the parasitophorous vacuole membrane takes place and the amastigote form enters in direct contact with host cell structures and organelles, and starts to divide. The presence of the parasite in the cytoplasm of the host cell did not induce significant changes in the distribution of actin filaments, microtubules, the Golgi complex, mitochondria and endosomes/lysosomes during the first 48 h of infection. Amastigote forms were seen close to the microtubules. After 72 h of interaction, the number of microtubules and microfilaments around the parasites was reduced and lysosomes and mitochondria were seen in between the parasites.

Actin Cytoskeleton↗
PubMed1998

Chemical and immunological characterization of a low molecular weight outer membrane protein of Salmonella typhi.

A new immunogenic outer membrane protein, Omp-28 (MW 28,000 and pI 4.6), was isolated from smooth Salmonella typhi cells by the use of an extracting medium containing 6 M urea, 1% deoxycholate and 5 mM EDTA. The purification of Omp-28 was performed by gel filtration and fast ion exchange chromatography. This protein showed to be the prevalent component isolated by the latter methodology. Omp-28 is formed by three identical subunits (MW 9,000), not linked by disulfide bonds. The partial N-terminal amino acid sequence of Omp-28 presented great homology with part of the sequence of an Escherichia coli protein found in a precursor whose sequence was predicted by c-DNA. ELISA and Western blotting identified Omp-28 as the major antigenic protein present in the outer membrane protein fraction, isolated by gel filtration. Antibodies against Omp-28 were detected by ELISA in 43% of 28 sera from typhoid fever convalescent patients. The antisera from mice immunized with Omp-28 and the highest positive typhoid fever convalescent serum gave a positive bactericidal test, killing 50% of Salmonella typhi cells in serum dilutions of 1/80 and 1/320, respectively. These results indicate the immunogenic importance of Omp-28 isolated from Salmonella typhi outer membrane and strongly suggest it should be used in further studies of animal protection against the disease caused by this pathogenic bacteria.

Amino Acid Sequence↗
PubMed1997

1,3-Dimethylisoguanine, a new purine from the marine sponge Amphimedon viridis.

A new purine, 1,3-dimethylisoguanine (1), has been isolated from the marine sponge Amphimedon viridis and identified by analysis of spectroscopic data. Compound 1 increased the contractions obtained by transmural electrical stimulation in the guinea pig longitudinal muscle/myenteric plexus in a dose-dependent manner.

Animals↗
PubMed1994

[Aneurysmal bone cysts of the spinal canal].

Aneurysmal bone cysts (ABC) are rare bone tumors of controversial pathogenesis. In 15% of cases, they are localized in the vertebrae. Despite the absence of anaplasia, their volume and localization are often responsible for incomplete surgical resection. The authors present 5 cases of primary vertebral ABC, 4 females and one male, localized in cervical (3 cases), dorsal (1 case) and lumbar (1 case) spine. Symptoms included rachialgia and torticollis. Radiological and histopathological examination disclosed the typical features of ABC. Pre-operative embolization (in 3 cases) and surgery (complete exeresis in all cases except one) were the therapeutic procedures. During a 39 month median period of follow-up, there was one local recurrence. The only case of incomplete exeresis show not did any evidence of progression until 36 months after operation.

Adolescent↗
PubMed1994

[Community reintegration of long-course psychiatric patients. Development of a residential structure].

Segregation from the community of long-term psychiatric patients leads to an increase in psychiatric disability. The rehabilitation process envisages the development of autonomy and personal realization and must be linked to a continuity of rendered care. In the resettlement of these patients there are priority needs to fulfill along with housing. Scarceness of community resources, in our country including accommodation facilities, led us to a project aimed at creating a residential unit within a pilot experiment. Essential points are focused, namely unit definition, staff formation, patient selection and training, community resources survey, financing and efficacy indicators. In conclusion, possible errors to avoid in the conception of a unit such as the one described are pointed out.

Community Mental Health Centers↗
PubMed1994

[Central neurocytomas].

Central neurocytomas are a well-characterized group of neuronal tumors usually arising in the supratentorial ventricular cavities. We describe the anatomical and clinical study of seven of these neoplasms. Patients were in the first four decades of life, and tumors were usually located in one of the lateral ventricles. Surgical resection was subtotal in 6 cases. Light microscopic examination revealed predominantly benign lesions with morphological features similar to the so-called ependymoma of the foramen of Monro, of the oligodendrogliomas, and of the neuroblastomas. Immunohistochemistry and electron microscopy confirmed the diagnosis in each case, showing expression of neuron specific enolase and synaptophysin and containing microtubuli, neurosecretory granules, and presynaptic vesicles. In agreement with the literature, the authors stress the benign behaviour of most of these tumors and the need for systematic immunohistochemical and ultrastructural study. The actual roles of the extent of resection and of postoperative radiotherapy are still a matter of discussion.

Adolescent↗