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Biomedical subjects

L A Teixeira

Publications and source records attributed to L A Teixeira.

At least 19 recordsLinked to original sources
PubMed2001

An efficient gene transfer system for hematopoietic cell line using transient and stable vectors.

The hematopoietic system represents an interesting model for gene transfer protocols. Here, we have evaluated the efficiency of a gene transfer system using the polycationic compound SuperFect (Qiagen) and the K562 hematopoietic cell line. Transient and stable vectors carrying the enhanced green fluorescent protein (EGFP) reporter gene were employed. The stable vector was constructed based on Epstein-Barr virus sequences such as EBV oriP (origin of replication) and EBNA (EBV nuclear antigen)-1, both for DNA replication. The transfection efficiency of the viable cells was estimated by flow cytometry at approximately 98% for transient and stable vectors. Transiently transfected cells presented optimal EGFP expression until day 2 when fluorescence started to decrease. In contrast, stable transfectants continuously expressed the marker gene product for 10 weeks in the presence of G418. Our results represent an efficient gene transfer method for K562 hematopoietic cells and may be used as an alternative approach for further gene transfer studies involving hematopoietic cells.

Cell Line↗
PubMed2000

Timing and force components in bilateral transfer of learning.

Bilateral transfer of perceptual and motor components in movement control was investigated through two experiments. In Experiment 1 a simple anticipatory timing task was practiced with either the preferred or the nonpreferred hand. After a short resting interval an additional set of trials was performed with the contralateral hand. In Experiment 2, the same experimental design was used to investigate bilateral transfer of fine force control in a wrist-flexion movement. Analysis of the results showed that bilateral transfer of learning took place for both anticipatory timing and force control, with more noticeable transfer of training for the former. Asymmetry in transfer was found for force control, with significant transfer only in the preferred-to-nonpreferred direction. Transfer of anticipatory timing occurred similarly in both directions. These results indicated anticipatory timing as a powerful component for bilateral transfer, while force control showed to be more dependent on practice with the specific muscular system.

Adolescent↗
PubMed1999

Emergence of mupirocin resistance in multiresistant Staphylococcus aureus clinical isolates belonging to Brazilian epidemic clone III::B:A.

Mupirocin is a topical antimicrobial agent that has been successfully used to eradicate methicillin-resistant Staphylococcus aureus from the anterior nares and other sites of patients and health care personnel. This report describes the acquisition of a novel mupirocin resistance gene (ileS) by an epidemic MRSA clone that is geographically widespread in Brazil.

Anti-Bacterial Agents↗
PubMed1999

Kinematics of kicking as a function of different sources of constraint on accuracy.

The kinematics of kicking were investigated using five experienced players at soccer. They were required to kick powerfully balls of two sizes under conditions with defined and undefined targets. High-velocity cameras were used for three-dimensional analysis. Analysis indicated that the defined target condition led to lower movement speeds and shorter movement times, while balls' sizes influenced only time after peak velocity.

Adult↗
PubMed1999

Is there manual asymmetry in movement preparation?

Manual asymmetry in response preparation was investigated in simple and complex movements by using simple reaction-time tasks. The simple movement consisted of lifting the index finger, while in the complex one subjects reversed direction of movement to hit a switch after reaching for and grasping a tennis ball. Analysis showed that performance with either the right or the left hand was equivalent, with longer latencies for reacting on the complex task in comparison to the simple one. These findings indicate similar capabilities of the right and the left cerebral hemispheres to prepare the motor system for action independently of the spatial requirements of movement.

Adult↗
PubMed1998

Development of visuomotor integration in learning to grasp a moving ball.

Specificity of visuomotor maps was investigated in the acquisition of a task of grasping a moving ball. Performance was initially assessed in four visual conditions of full vision, visual occlusion of 100 msec., 200 msec., and 300 msec. preceding contact between the ball and hand. During acquisition one group practiced under full vision and another one with visual occlusion of 300 msec. A posttest was performed with the same visual conditions as the pretest, and in a subsequent transfer phase the groups reversed their visual conditions. The analysis of proportion of prehensions and movement kinematics indicated that practice in either experimental condition resulted in transfer to performance in different visual conditions.

Adult↗
PubMed1997

[From race to health in Master and slave].

The article analyzes how Gilberto Freyre addresses health-related issues in his book Master and slave. the first point of focus is how the sanitation movement that emerged in the sertão region in the late 1910s influenced Freyre's essay. The article next endeavors to understand the relation between Freyre's emphasis on the problem of syphilis in Brazil and the issues of race and miscegenation, both of which are constants in his works. Lastly, the article endeavors to situate Freyre's ideas within the ideological framework of eugenics that was in fashion in Brazil at the time his works were written.

Brazil↗
PubMed1996

Emergence of a methicillin-resistant Staphylococcus aureus clone related to the Brazilian epidemic clone III::B:A causing invasive disease among AIDS patients in a Brazilian hospital.

In a previous study we described the extensive geographic spread of a multidrug-resistant methicillin-resistant Staphylococcus aureus (MRSA) clone in hospitals located in the southern, southeastern, and northern parts of Brazil. In this study we used a set of molecular markers to demonstrate the emergence of a novel MRSA clone distinct from but closely related to the widely spread Brazilian epidemic clone. The new MRSA clone caused an outbreak among acquired immunodeficiency syndrome patients in a Brazilian hospital specializing in tropical diseases and human immunodeficiency virus- and human T-cell leukemia virus (HLTV)-related infections.

Acquired Immunodeficiency Syndrome↗
PubMed1995

Novel penicillin-resistant clones of Streptococcus pneumoniae in the Czech Republic and in Slovakia.

Seventy-two penicillin-resistant Streptococcus pneumoniae isolates collected from clinical specimens in the Czech and Slovakian Republics between 1990 and 1992 were analyzed by a variety of molecular techniques. Most of the highly resistant isolates (40/72) (penicillin MIC between 1 up to 16 micrograms/ml) were represented by two distinct pneumococcal clones, and most of these isolates (35/40) were also resistant to at least two other antibiotics (tetracycline plus chloramphenicol or erythromycin). All 17 isolates belonging to the first clone were of serotype 14, had very high penicillin MICs (8-12 micrograms/ml), shared a common, abnormal penicillin-binding protein (PBP) pattern and one of two related pulsed-field gel electrophoretic (PFGE) patterns. The 15 isolates belonging to the second clone were all of serotype 19A, had penicillin MICs between 1 and 4 micrograms/ml, shared a unique, abnormal PBP pattern, and could be divided into two subgroups on the basis of PFGE patterns, one of which was indistinguishable from the PFGE pattern of a multiresistant capsular type 19A clone of S. pneumoniae already identified earlier in Hungary. Thirty-two of the 72 pneumococcal isolates had lower penicillin MICs (0.1-0.5 microgram/ml), and these isolates differed from the more highly resistant ones in several respects: They belonged to seven different serotypes, showed large variation in PFGE patterns (20 patterns in 32 isolates) and most of them (21/32) were resistant to penicillin only. Tentative explanations for these findings, in terms of epidemiological and molecular mechanisms, are considered.

Bacterial Proteins↗
PubMed1995

Geographic spread of epidemic multiresistant Staphylococcus aureus clone in Brazil.

Staphylococcus aureus isolates from five large teaching hospitals and one medium-size community hospital located in geographically distant parts of Brazil, in the south and southeast (Rio de Janeiro, Niteroi, Sao Paulo, Porto Alegre) and in the north (Manaus), were tested for their antibiotic resistance patterns and genetic backgrounds. Eighty-five of the 152 isolates were identified as methicillin-resistant S. aureus (MRSA) by using a combination of an agar dilution screen and a mecA gene-specific DNA probe. All MRSA isolates were resistant to penicillin, erythromycin, gentamicin, oxacillin, and cephalothin, and the majority of isolates (74%) were also resistant to chloramphenicol, sulfamethoxazole-trimethoprim, ciprofloxacin, and clindamycin as well and were susceptible only to vancomycin. Isolates obtained from hospitals in Sao Paulo, Rio de Janeiro, Niteroi, and Porto Alegre (1,600 km from one another) and Manaus (3,700 km from Rio de Janeiro) were examined by a variety of molecular fingerprinting techniques: the nature of the mecA polymorph and Tn554 attachment sites and restriction fragment length polymorphism of genomic DNAs after SmaI restriction and separation of the digested DNA by pulsed-field gel electrophoresis. The overwhelming majority of the isolates shared a common pulsed-field gel electrophoresis pattern and carried mecA polymorph III in combination with Tn554 pattern B, indicating the presence of a single, epidemic MRSA clone spread over large geographic distances of Brazil.

Brazil↗
PubMed1993

Sialic acid content and surface hydrophobicity of group B streptococci.

The sialic acid content and the cell-surface hydrophobicity index of 40 group B streptococci (GBS) strains were assessed. GBS isolated from invasive infections (virulent strains) presented an increased level of sialic acid content (1.4%) when compared with GBS isolated from asymptomatic patients (0.53%). Treatment of GBS strain 85634 with neuraminidase resulted in a decrease (about 25%) in the net negative surface charge as assessed by cell electrophoresis. This finding suggests that sialic acid residues are important anionogenic groups exposed on GBS cell surface. N-acetylneuraminic acid was the only sialic acid derivative characterized in the strain 85634 as evaluated by gas-liquid chromatography. GBS from different serotypes presented a hydrophobic index mean value of 0.9. Even though the sialic acid contributed effectively to the negative charge on GBS cell surface, no difference was observed in the hydrophobic index when virulent and avirulent strains were compared.

Female↗
PubMed1992

Liquid medium for rapid presumptive identification of group B streptococci.

A suitable test was developed for distinguishing group B streptococci from other beta-hemolytic streptococci during growth in liquid medium. One hundred and sixty of 161 human group B strains tested yielded positive reactions within a 5 h incubation. The dye medium tested is a reliable substitute for more expensive serological procedures.

Animals↗
PubMed1992

[Not Available].

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Academies and Institutes↗
PubMed1990

[Transposition of masseter muscle insertion and its influence on anatomical musculo-skeletal changes in the adult rabbit].

Unilateral surgical transposition of the masseter muscle from the masseteric fossa to the central area of the mandibular body below the molar teeth was performed in ten adult rabbits. Six months later the animals were sacrificed, the masseter muscles were dissected and then removed to be fully dried and weighed; the skull was cleaned for anatomical examination of the mandible and the teeth. It was noticed that the transposed muscles were firmly attached and functionally adapted, but underwent a drastic reduction of their weight. The smooth surface of the mandibular body which became activated by the new muscular pull was now rough and irregular due to osseous neoformation. The original area of attachment (masseteric fossa) was remodelled not only regressively but also by bone apposition (exostoses) in some sites. The dental arches kept normal, except for alveolar bone resorption next to the first molar in two animals and accentuated sagittal deviation in another one.

Alveolar Bone Loss↗