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Biomedical subjects

S M Bueno

Publications and source records attributed to S M Bueno.

14 recordsLinked to original sources
PubMed1997

Strategies for the depyrogenation of contaminated immunoglobulin G solutions by histidine-immobilized hollow fiber membrane.

The depyrogenation of different IgG solutions using the histidine-linked hollow fiber membrane developed in our laboratory is presented here. Three strategies for endotoxin (ET) removal were investigated according to the immobilized histidine's ability to bind different immunoglobulins: (1) ET removal from 1 mg/ml non histidine-binding mouse monoclonal IgG1 (MabCD4) solution was achieved in the presence of acetate buffer (pH 5.0) without any protein loss. (2) For contaminated human IgG, combined adsorption of ET and IgG in the presence of MOPS of Tris buffer was tested, followed by differential elution using increasing salt concentrations. This attempt was not successful since ET were quantitatively found in the IgG elution fraction. (3) Alternatively, it was proposed to adsorb selectively ET in the presence of acetate buffer (pH 5.0) under non binding conditions for human IgG. Human IgG could then be purified if necessary with the same membrane in the presence of MOPS buffer (pH 6.5). With a 1 m2 histidine-PEVA module under these operating conditions, it is estimated that the depyrogenation of 3 l of 1 mg/ml IgG (human or murine) solution containing 80 EU/ml of ET should be possible.

Adsorption↗
PubMed1997

[Educational communication between nurses and students about sexual health promotion].

As school has been a crucial space for the development of knowledge and abilities in order to assure changes of behavior and considering the lack of reports about sexuality and STD/AIDS to the students, the present study aims to search scholars from three classes of high school, from a town surrounding the city of Ribeirão Preto-São Paulo. Authors identified students' problems by carrying out and assessing joint educative actions on the problems that have been found. Results have showed that these students relate AIDS to fatality and temerity and perhaps they are influenced by the message issued at the first decade of the history of this disease while now, the tendency is to work with up to date knowledge and abilities. They form an opinion about AIDS as a sex and preventible disease. A it however, authors detected misinformation in another basic aspects. Therefore, we suggest nurses to work hard with this question.

Acquired Immunodeficiency Syndrome↗
PubMed1997

[Leisure--a way to alleviate tension in the work environment of an intensive care unit: a concept of the nursing team].

In the present study, we aimed at verifying close to ICU nursing team the service representation and this unit meaning, looking at finding the sense of leisure and its implication in the professional environment. We worked with DUMAZEDIER framework, considering the application of leisure in health promotion, through a quali-quantitative survey. We have investigated 10 members of the nursing team, among different categories, most of them were women, half single, from 28 to 45 years old, with predominantly 10 years in service. They showed pleasure in their job (90%), although they consider it stressing (50%). The job was identified as assistance (80%) and requiring vocation/donation (50%). They also showed relationship and communication. They have the concept of leisure as entertainment/deconcentration (80%), relaxation (20%) etc., emphasizing the importance of discussing the theme. They admit tension/stress caused in the location, considering the need of leisure in the service, to help communication and alleviate the tension. We suggest to nurses special attention on this.

Adult↗
PubMed1996

Cytomegalovirus antigenemia in acquired immunodeficiency syndrome patients with untreated cytomegalovirus retinitis.

PURPOSE: To determine the frequency of cytomegalovirus (CMV) viremia in patients with acquired immunodeficiency syndrome (AIDS) and untreated CMV retinitis using conventional cell culture isolation and the sensitive CMV antigenemia assay. METHODS: We examined 24 AIDS patients with ophthalmologic diagnosis of untreated CMV retinitis and 24 AIDS patients without present or past retinitis (control patients) from three medical centers between September 1992 and March 1994. Cytomegalovirus antigenemia was detected by an indirect peroxidase staining in 300,000 cytocentrifuged neutrophils, using a mixture of murine monoclonal antibodies directed against the pp65 lower matrix protein of CMV. RESULTS: Positive antigenemia was demonstrated in eight (33.3%) of the 24 retinitis patients and in none of the 24 control patients (P < .001). Only two of the eight antigenemia-positive patients had a concurrent positive CMV isolation from blood leukocytes by conventional cell culture assay. CONCLUSIONS: These results emphasize the risk of extraocular disease in AIDS patients with CMV retinitis because the virus is often present in peripheral blood leukocytes. The CMV antigenemia assay may be a simple and rapid means of identifying those patients with unilateral retinitis at highest risk of developing CMV retinitis of the fellow eye or of visceral CMV disease if intravitreal injections or implants are used as sole treatment for CMV retinitis.

AIDS-Related Opportunistic Infections↗
PubMed1995

Interaction of human immunoglobulin G with l-histidine immobilized onto poly(ethylene vinyl alcohol) hollow-fiber membranes.

L-Histidine as pseudobiospecific ligand was immobilized onto poly(ethylene vinyl alcohol) hollow-fiber membranes to obtain an affinity support for immunoglobulin G (IgG) purification. The interaction of human IgG with the affinity membranes was studied by chromatography and equilibrium binding analysis. Adsorption was possible over a broad pH range and was found to depend strongly on the nature of the buffer ions rather than on ionic strength. With zwitterionic buffers like morpholinopropanesulfonic acid (Mops) and hydroxyethylpiperazineethanesulfonic acid (Hepes), much higher adsorption capacities were obtained than with other buffers like Tris-HCl and phosphate buffers. An inhibition analysis revealed that non-zwitterionic buffers competitively inhibit IgG binding, whereas Mops and Hepes in their zwitterionic form do not. By choosing the appropriate buffer system, it was possible to adsorb specifically different IgG subsets. The IgG molecules were found to adsorb on membrane immobilized histidine via their Fab part. Determination of dissociation constants at different temperatures allowed calculation of thermodynamic adsorption parameters. Decrease in KD with increasing temperature and a positive entropy value between 20 and 35 degrees C (in Mops buffer) indicated that adsorption is partially governed by hydrophobic forces in that temperature range, whereas at lower temperatures, electrostatic forces are more important for adsorption.

Adsorption↗
PubMed1995

Separation of immunoglobulin G from human serum by pseudobioaffinity chromatography using immobilized L-histidine in hollow fibre membranes.

L-Histidine, intended as a pseudobiospecific ligand, was immobilized on poly(ethylenevinyl alcohol) hollow fibre membranes after their activation with epichlorohydrin or butanediol diglycidyl ether. The affinity membranes obtained allowed the one-step separation of immunoglobulin G (IgG) from untreated human serum. Elution was possible under mild conditions with discontinuous pH or salt gradients. IgM was also adsorbed to a certain extent and partially separated from IgG by pH gradient elution. The bound IgG fractions showed pI values between 8 and 9.5 and contained IgG1 and IgG3. The dissociation constants for IgG on the bisoxirane- and epichlorohydrin-activated membranes coupled with histidine were determined by equilibrium binding analysis to be 2.5 x 10(-5) and 2.0 x 10(-5) M, respectively. The maximum binding capacity of the affinity hollow fibre membranes was 80 and 70 mg of IgG per gram of support, respectively. With a cartridge of surface area 1 m2 (about 19 g of fibres), during a 60-min run, theoretically up to 1.5 g of IgG can be removed from human serum. The histidine affinity membranes are very stable owing to the simple nature of the ligand and the coupling via an ether linkage. Reproducible results were obtained over more than 1 year even with untreated human serum being used regularly.

Adsorption↗
PubMed1995

In vitro removal of human IgG by pseudobiospecific affinity membrane filtration on a large scale. A preliminary report.

We have developed a pseudobiospecific affinity membrane device for selective removal of human IgG from plasma or serum in vitro for clinical apheresis application. The pseudobiospecific affinity ligand L-histidine was immobilized through an ether linkage onto poly(ethylenevinyl alcohol) hollow fiber cartridge. The obtained affinity membranes showed high selectivity for IgG adsorption from untreated human serum. These membranes are able to adsorb IgG1, IgG2, IgG3 if Mops buffer is used, and more selectively IgG1, and IgG3 in Tris-HCl buffer. With respect to the binding capacity, the pseudobiospecific affinity membrane used showed a higher capacity as compared to protein A-membranes described in the literature. Due to the high capacity, specificity and stability of the histidine affinity membranes, in addition to their lower cost, the approach proposed in this paper may offer a useful alternative to protein A based devices in the treatment of immune-related diseases.

Adsorption↗
PubMed1991

[Sexually transmitted diseases: concepts, attitudes and perceptions among dustmen].

The concepts regarding sexually transmitted diseases (STD) of 41 (63.07%) dustmen of a country town in S. Paulo State, Brazil, are presented in order to provide support for the preparation of health education programmes on STD for this and similar populational groups. The data collected from interviews with these workers show that a considerable number of them have inadequate concepts about STD. These results demonstrate the lack of information and education on this subject, and the need to implement educational activities.

Adolescent↗
PubMedDate not supplied

[Knowledge about AIDS among rural workers].

The objective of the present study was to identify the knowledge rural workers have about AIDS in order to develop a specific educational projects. It was observed that part of the population which spontaneously participated in the study presented characteristics of misinformation and alienation about AIDS, as well as about situations that may pose risks to workers. On the basis of the responses obtained, an educational project about AIDS was elaborated to reach 1300 workers employed at a Sugar and Alcohol Mill.

Acquired Immunodeficiency Syndrome↗