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Biomedical subjects

M C Neves

Publications and source records attributed to M C Neves.

14 recordsLinked to original sources
PubMed2006

Synthesis of SiO2-coated Bi2S3/poly(styrene) nanocomposites by in-situ polymerization.

New nanocomposites containing silica-coated Bi2S3 nanofibers were synthesised by in situ polymerization using two distinct synthetic strategies: emulsion and suspension polymerization. Transmission and scanning electron microscopy of the nanocomposite particles showed that in both cases the Bi2S3/SiO2 nanoparticles were densely coated with poly(styrene). In situ emulsion polymerization afforded nanocomposites in which the nanofibers were coated with polymer spheres whilst suspension polymerization gives rise to a homogeneous polymer layer coat. The morphology of the poly(styrene) coating observed is discussed considering the surface modification of the nanofibers and the polymerization technique involved.

Bismuth↗
PubMed1999

[Paradoxical expansive lesions of cerebral tuberculosis during antitubercular drug therapy].

Central nervous system involvement by tuberculosis presents two main types: tuberculosis meningitis or tuberculoma. This second condition has nowadays ideal conditions for development. We report three patients who developed paradoxical brain tuberculosis expansive lesion during the use of tuberculostatic drugs. The cases point out the importance of tomography follow up of patients who present neurological signs in the course of treatment for tuberculosis. The first two patients presented onset of the a neurological symptoms, associated with lung tuberculosis. The third patient previously had tuberculous meningitis. Computerized tomography was used to follow up these patients. Tuberculostatic and corticoid drugs were used for treatment.

Adult↗
PubMed1998

Slipped capital femoral epiphysis. A report of 4 cases occurring in one family.

We describe slipped capital femoral epiphysis in 4 members of a black, obese family, who were all first-degree relatives. The aetiology of slipped capital femoral epiphysis is unknown, although it is thought to be multifactorial. Genetic predisposition and environmental factors have been associated with the condition. A familial incidence with at least two cases in the same family has been reported. In epidemiological studies, this incidence ranges from 3% to 35%. Our cases were investigated in an attempt to find a possible aetiological genetic factor. A genetic predisposition with an autosomal dominant pattern of transmission is suggested, although environmental variables must be considered as provocative factors.

Adolescent↗
PubMed1997

Molecular detection of streptomycin-producing streptomycetes in Brazilian soils.

Actinomycetes were isolated from soybean rhizosphere soil collected as two field sites in Brazil. All the isolates were identified as Streptomyces species and were screened for streptomycin production and the presence of two genes, strA and strB1, known to be involved in streptomycin biosynthesis in Streptomyces griseus. Antibiotic resistance profiles were determined for 53 isolates from cultivated and uncultivated sites, and approximately half the strains were streptomycin resistance. Clustering by the unweighted pair group method with averages indicated the presence of two major clusters, with the majority of resistant strains from cultivated sites being placed in cluster 1. Only representatives from this cluster contained strA. Streptomycetes containing strA and strB1 were phenotypically diverse, and only half could be assigned to known species. Sequence comparison of 16S rRNA and trpBA (tryptophan synthetase) genes revealed that streptomycin- producing streptomycetes were phylogenetically diverse. It appeared that a population of streptomycetes had colonized the rhizosphere and that a proportion of these were capable of streptomycin production.

Amino Acid Sequence↗
PubMed1996

LASIK for high myopia: one year experience.

BACKGROUND AND OBJECTIVE: Laser in situ keratomileusis (LASIK) is a technique combining the advantages of lamellar corneal surgery (not disturbing Bowman's layer) with the precision of excimer laser surgery. It can be used to correct myopia in a wide range of diopters. In this study we present our data on the first 34 consecutive cases of myopia correction by LASIK. PATIENTS AND METHODS: Thirty four eyes of 27 patients with myopia ranging from -10.00 to -22.50 diopters (D) were operated with LASIK. The follow-up was from six months to one year. The mean age was 33.02 +/- 7.98 years, 32.4% were males and 67.6% were females. Surgery was always performed with the Chiron Automated corneal shaper resecting a corneal flap of 160 mu and then ablating the stromal bed (OZ 4.50 mm) with the Summit OmniMed 5.0 excimer laser. The parameters used to assess the results were predictability, safety (variation of spectacle corrected visual acuity), stability, and patient satisfaction. RESULTS: Of the patients, 67.65% were between -1.00 and +1.00 at 6 months; 44.11% of eyes retained the same spectacle corrected visual acuity, 11.76% gained 1 line, 26.47% gained 2 lines, 8.82% lost 1 line and 8.82% lost 2 lines. Refraction at 1 month was 0.07 +/- 1.99 (range, -4.00 to +4.00); at 3 months 0.61 +/- 1.69 (range, -4.25 to +2.25); and at 6 months 0.81 +/- 1.71 (range, -4.75 to +2.25). Of the patients, 85.3% were happy with the procedure. Complications included two dislocated caps in the immediately post-operative period and two cases of epithelial ingrowth under the cap. Two eyes developed irregular astigmatism. These complications were found in the first two sessions of surgery and are related to the learning curve of the method. CONCLUSION: Results suggest that LASIK is a viable method for correction of high myopia with few complications and may have advantages over keratomileusis and PRK as it combines the best features of both methods--it preserves Bowman's layer and has the excimer laser precision. Refining the nomogram of ablation should result in even better results.

Adult↗
PubMed1993

Differential effects of Mandevilla velutina compounds on paw oedema induced by phospholipase A2 and phospholipase C.

This study compares the effect of Mandevilla velutina compounds with some anti-inflammatory drugs against phospholipase A2- and phospholipase C-induced rat hindpaw oedema. Injection of phospholipase A2 (Naja naja, 2.5-20 U/paw) and phospholipase C (Clostridium perfringens, 0.03-0.05 U/paw) caused a dose-and-time-related increase in paw oedema. Compounds MV 8608 (55 mumol/kg) and MV 8612 (32 mumol/kg, i.p.) inhibited phospholipase A2-induced paw oedema without interfering with phospholipase C-induced oedema. Local injection of both M. velutina compounds also partially attenuated the oedema evoked by phospholipases A2 and C. Dexamethasone (1.3 mumol/kg, p.o.) suppressed only phospholipase A2-induced paw oedema, while indomethacin (11 mumol/kg, p.o.) attenuated only the early phase of phospholipase C-induced oedema. By contrast, phenidone (616 mumol/kg, i.p.) inhibited only phospholipase C-induced oedema, while cyproheptadine (31 mumol/kg) and pyrilamine (100 mumol/kg, p.o.) inhibited only phospholipase A2 oedema. Treatment of animals with compound 48/80 markedly suppressed phospholipase A2-induced paw oedema and to a lesser degree the oedema caused by phospholipase C. Our results indicate that there are marked differences regarding the mechanisms underlying the paw oedema responses caused by phospholipase A2 and phospholipase C. In addition, our data show that M. velutina compounds cause potent and long-lasting inhibition of the pro-inflammatory action of phospholipase A2, an effect which may account for their reported anti-inflammatory activities.

Animals↗
PubMed1993

[Stereology of the myocardium in human fetus. Quantitative study of the structural changes in the last two trimesters of gestation].

PURPOSE: Quantitative study of the human myocardial comparing the 2nd and 3rd trimesters of gestation. METHODS: Fragments of the myocardium were collected from 8 fetal human hearts (4 from 2nd and 4 from 3rd trimesters) and prepared by histological methods. Fifteen random fields from each region were analyzed considering independently myocytes, connective tissue and vessels. Stereological determinations were possible by counting test-points and intersections on a multipurpose test lattice (M42). RESULTS: Stereological differences between last 2 trimesters of gestation were not significant (p > 0.05). The volume density was myocyte (including nucleus) = 75.6% in 2nd trimester and 67.7% in 3rd trimester; vessels = 3.7% in 2nd trimester and 6.4% in 3rd trimester; connective tissue (interstitial substance without vessels) = 20.6 to 25.9% for 2nd and 3rd trimesters respectively. However, considering the nuclei of the myocytes differences between last 2 trimesters were significant (p = 0.004). The volume density of the nuclei had a reduction from 2nd to 3rd trimesters (from 15.2 to 8.1% respectively). CONCLUSION: This result suggests decreasing synthesis of proteins from nucleus of myocyte in the last 2 gestational trimesters, but without quantitative important changes in the cardiac tissue, probably in relation to the reduction of the myocardial cellular multiplication.

Female↗
PubMed1988

Pathologic studies of total joint replacement.

Articular endoprostheses are, in effect, foreign bodies designed to re-establish functioning articulations and are, therefore, capable of eliciting a local or systemic response to their presence. This article discusses the body's reactions to foreign bodies in general, and to endoprostheses in particular, and attempts to place those reactions into perspective regarding survival and failure of articular endoprostheses. The effects of size, shape, and composition of the materials used in the prosthetic components, and the mechanical factors acting on them to produce debris, are presented.

Bone and Bones↗
PubMedDate not supplied

Absorption of intra-bronchial diprophylline-methodology and preliminary results.

With the objective of measuring alveolo-capillary permeability, a diprophylline solution (molecular weight 254 D) was instilled as a bolus. Instillation was performed through distallized impacted fiber bronchoscope and 3 normal volunteers and 3 patients with pulmonary fibrosis were evaluated. Blood samples were collected at regular intervals with subsequent pharmacokinetic study, mainly aimed at determining absorption kinetics. This technique enabled us to distinguish the two groups of individuals which had different absorption rates. In controls, kinetics apparently followed a simple, one compartment model for absorption, which was slower and occurred to a lesser extent. Patients with a pulmonary fibrosis had a faster and higher degree of absorption, with a larger plasma Cmax. In the latter group two-compartment kinetics for absorption was found. We conclude that absorption kinetic parameters can disclose data on structural integrity of epithelia and possible lesions of the lung interstitium.

Absorption↗
PubMedDate not supplied

The anatomy and histology of the inferior glenohumeral ligament complex of the shoulder.

The gross and histologic anatomy of the inferior glenohumeral ligament was studied in 11 fresh frozen cadaver shoulders. Arthroscopic observations of the joint capsule through the normal range of motion revealed that the inferior glenohumeral ligament is actually a complex of structures consisting of an anterior band, a posterior band, and an interposed axillary pouch. While these components of the inferior glenohumeral ligament complex were present in all 11 specimens, they were best demonstrated in some shoulders by placing the humeral head in internal or external rotation in varying degrees of abduction. Histologic examination of the joint capsule revealed that the anterior and posterior bands of the inferior glenohumeral ligament complex were readily identifiable as distinct structures comprised of thickened bands of well-organized collagen bundles. Although slight variations were noted in the attachment sites of the anterior and posterior bands to the glenoid, the inferior glenohumeral ligament complex was observed to attach to the humeral neck in one of two distinct configurations. A collar-like attachment, in which the entire inferior glenohumeral ligament complex attaches just inferior to the articular edge of the humeral head, was observed in six specimens. In the remaining five specimens, the attachment was in the shape of a "V," with the anterior and posterior bands attaching adjacent to the articular edge of the humeral head and the axillary pouch attaching at the apex of the "V" distal to the articular edge. The orientation and design of the inferior glenohumeral ligament complex supports the functional concept of this single structure as an important anterior and posterior stabilizer of the shoulder joint.

Arthroscopy↗
PubMedDate not supplied

[Quantitative Growth of the human fetal larynx: allometric study between the 9th and 38th weeks post-conception].

The ponderal growth of the larynx was studied in human fetal period between the 9th and 38th weeks post-conception (w.p.c.). The larynx weight (in grams - g) was related with body weight (in grams -g) using the allometric equation Y= ax(b). Our results indicated that relative growth of the larynx is allometric negative (b= 0.55, p < 0.001). These data are important in estimating the fetal gestational age after non-invasive investigation (MR, CT and ultrasound).

English Abstract↗
PubMedDate not supplied

Posterior chamber silicone phakic intraocular lens.

BACKGROUND: We investigated the efficacy, safety, and stability of correction achieved with a silicone posterior chamber intraocular lens used to correct high myopia in phakic eyes. PATIENTS AND METHODS: A silicone posterior chamber plate-style intraocular lens (Chiron, Adatomed) was implanted in 38 consecutive phakic eyes with high myopia (-7.00 to -28.00 diopters (D) over a period of 21 months. Follow-up ranged from 3 to 24 months. RESULTS: Three months after surgery, refractions in 27 eyes (71%) ranged from -1.00 to +1.00 D and remained stable thereafter. Spectacle-corrected visual acuity improved at least two lines in 24 eyes (63%), and none was lost in any eye. Patient satisfaction was high (92%). The few complications that occurred were mostly related to imperfections in the surgical technique rather than lack of biocompatibility of the lens. No cataract or other vision-threatening complication was present at the end of the study. CONCLUSION: This silicone posterior chamber plate-style intraocular lens provides a reasonably predictable, safe, and stable means of correcting high myopia.

Adult↗
PubMedDate not supplied

Our experience with granulomatous rhinitis. A new occupational disease.

From the study of two groups of patients-133 cases of Extrinsic Pulmonary Granulomatoses (E.P.G.) and 360 cases of exposure to various occupational environments who were routinely submitted to nasal biopsies the authors conclude that granulomatous rhinitis is either a manifestation of E.P.G. or an independent entity which can appear in individuals exposed to polluted environments. On the other hand, nasal biopsy is, in their opinion, a good diagnostic tool for Granulomatous Rhinitis and can also be usefull for diagnosing E.P.G.

Air Pollutants, Occupational↗