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1.
Health Educ Res ; 31(2): 260-72, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-26956041

RESUMO

Partner negotiation and insertion difficulties are key barriers to female condom (FC) use in sub-Saharan Africa. Few FC interventions have provided comprehensive training in both negotiation and insertion skills, or focused on university students. In this study we explored whether training in FC insertion and partner negotiation influenced young women's FC use. 296 female students at a South African university were randomized to a one-session didactic information-only minimal intervention (n= 149) or a two-session cognitive-behavioral enhanced intervention (n= 147), which received additional information specific to partner negotiation and FC insertion. Both groups received FCs. We report the 'experiences of' 39 randomly selected female students who participated in post-intervention qualitative interviews. Two-thirds of women reported FC use. Most women (n= 30/39) applied information learned during the interventions to negotiate with partners. Women reported that FC insertion practice increased their confidence. Twelve women failed to convince male partners to use the FC, often due to its physical attributes or partners' lack of knowledge about insertion. FC educational and skills training can help facilitate use, improve attitudes toward the device and help women to successfully negotiate safer sex with partners. Innovative strategies and tailored interventions are needed to increase widespread FC adoption.


Assuntos
Preservativos Femininos/estatística & dados numéricos , Educação em Saúde/organização & administração , Conhecimentos, Atitudes e Prática em Saúde , Negociação , Parceiros Sexuais/psicologia , Feminino , Humanos , Gravidez , Gravidez não Planejada , Sexo Seguro , Infecções Sexualmente Transmissíveis/prevenção & controle , África do Sul , Universidades , Adulto Jovem
2.
AIDS Behav ; 19(9): 1666-75, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-25711300

RESUMO

Intended conception likely contributes to a significant proportion of new HIV infections in South Africa. Safer conception strategies require healthcare provider-client communication about fertility intentions, periconception risks, and options to modify those risks. We conducted in-depth interviews with 35 HIV-infected men and women accessing care in South Africa to explore barriers and promoters to patient-provider communication around fertility desires and intentions. Few participants had discussed personal fertility goals with providers. Discussions about pregnancy focused on maternal and child health, not sexual HIV transmission; no participants had received tailored safer conception advice. Although participants welcomed safer conception counseling, barriers to client-initiated discussions included narrowly focused prevention messages and perceptions that periconception transmission risk is not modifiable. Supporting providers to assess clients' fertility intentions and offer appropriate advice, and public health campaigns that address sexual HIV transmission in the context of conception may improve awareness of and access to safer conception strategies.


Assuntos
Preservativos/estatística & dados numéricos , Aconselhamento , Fertilização , Infecções por HIV/prevenção & controle , Intenção , Relações Profissional-Paciente , Adulto , Feminino , Infecções por HIV/psicologia , Conhecimentos, Atitudes e Prática em Saúde , Pessoal de Saúde/psicologia , Humanos , Masculino , Motivação , Gravidez , Complicações Infecciosas na Gravidez/prevenção & controle , Parceiros Sexuais , África do Sul
3.
AIDS Behav ; 19(12): 2291-303, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26080688

RESUMO

HIV-infected men and women who choose to conceive risk infecting their partners. To inform safer conception programs we surveyed HIV risk behavior prior to recent pregnancy amongst South African, HIV-infected women (N = 209) and men (N = 82) recruited from antenatal and antiretroviral clinics, respectively, and reporting an uninfected or unknown-HIV-serostatus pregnancy partner. All participants knew their HIV-positive serostatus prior to the referent pregnancy. Only 11 % of women and 5 % of men had planned the pregnancy; 40 % of women and 27 % of men reported serostatus disclosure to their partner before conception. Knowledge of safer conception strategies was low. Around two-thirds reported consistent condom use, 41 % of women and 88 % of men reported antiretroviral therapy, and a third of women reported male partner circumcision prior to the referent pregnancy. Seven women (3 %) and two men (2 %) reported limiting sex without condoms to peak fertility. None reported sperm washing or manual insemination. Safer conception behaviors including HIV-serostatus disclosure, condom use, and ART at the time of conception were not associated with desired pregnancy. In light of low pregnancy planning and HIV-serostatus disclosure, interventions to improve understandings of serodiscordance and motivate mutual HIV-serostatus disclosure and pregnancy planning are necessary first steps before couples or individuals can implement specific safer conception strategies.


Assuntos
Infecções por HIV/transmissão , Assunção de Riscos , Sexo Seguro , Parceiros Sexuais , Adulto , Preservativos , Feminino , Infecções por HIV/epidemiologia , Soropositividade para HIV , Humanos , Masculino , Gravidez , Comportamento Sexual , África do Sul , Adulto Jovem
4.
AIDS Care ; 27(1): 25-30, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25202986

RESUMO

Men and women living with HIV with access to ARVs are living longer, healthier lives that can and often do include bearing children. Children occupy a key space in men and women's personal and social lives and often play a fundamental role in maintaining these relationships, irrespective of illness concerns. Couples living with HIV need to balance prevention needs and ill-health while trying to maintain healthy relationships. Health-care providers serving the reproductive needs of HIV-affected couples need to consider the social and relational factors shaping reproductive decisions associated with periconception risk behaviors. This paper based on qualitative research at three hospital sites in eThekwini District, South Africa, investigates the childbearing intentions and needs of people living with HIV (PLHIV), and the attitudes and experiences of health-care providers serving the reproductive needs of PLHIV, and client and provider views and knowledge of safer conception. This research revealed that personal, social, and relationship dynamics shape the reproductive decisions of PLHIV, and "unplanned" pregnancies are not always unintended. Additionally, conception desires are not driven by the number of living children; rather clients are motivated by whether or not they have had any children with their current partner/spouse. Providers should consider the relationship status of clients in discussions about childbearing desires and intentions. Although many providers recognize the complex social realities shaping their clients' reproductive decisions, they have outdated information on serving their reproductive needs. Appropriate training to enable providers to better understand the relationship and social realities surrounding their clients' childbearing intentions is required and should be used as a platform for couples to work together with providers toward safer conception. The adoption of a more participatory approach should be employed to equalize client-provider power dynamics and to ensure clients are more involved in decision-making about reproduction and conception.


Assuntos
Infecções por HIV/fisiopatologia , Intenção , Relações Profissional-Paciente , Reprodução , Infecções por HIV/psicologia , Humanos
5.
Infect Dis Obstet Gynecol ; 2012: 146348, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22927713

RESUMO

BACKGROUND: Understanding HIV-infected patient experiences and perceptions of reproductive counseling in the health care context is critical to inform design of effective pharmaco-behavioral interventions that minimize periconception HIV risk and support HIV-affected couples to realize their fertility goals. METHODS: We conducted semistructured, in-depth interviews with 30 HIV-infected women (with pregnancy in prior year) and 20 HIV-infected men, all reporting serodiscordant partners and accessing care in Durban, South Africa. We investigated patient-reported experiences with safer conception counseling from health care workers (HCWs). Interview transcripts were reviewed and coded using content analysis for conceptual categories and emergent themes. RESULTS: The study findings indicate that HIV-infected patients recognize HCWs as a resource for periconception-related information and are receptive to speaking to a HCW prior to becoming pregnant, but seldom seek or receive conception advice in the clinic setting. HIV nondisclosure and unplanned pregnancy are important intervening factors. When advice is shared, patients reported receiving a range of information. Male participants showed particular interest in accessing safer conception information. CONCLUSIONS: HIV-infected men and women with serodiscordant partners are receptive to the idea of safer conception counseling. HCWs need to be supported to routinely initiate accurate safer conception counseling with HIV-infected patients of reproductive age.


Assuntos
Anticoncepção/psicologia , Aconselhamento/métodos , Infecções por HIV/psicologia , Pessoal de Saúde/psicologia , Complicações Infecciosas na Gravidez/psicologia , Adolescente , Adulto , Atitude Frente a Saúde , Aconselhamento/normas , Feminino , Soropositividade para HIV , Humanos , Masculino , Pessoa de Meia-Idade , Gravidez , Complicações Infecciosas na Gravidez/prevenção & controle , Parceiros Sexuais , Fatores Socioeconômicos , África do Sul , Adulto Jovem
6.
S Afr Med J ; 110(6): 514-518, 2020 May 29.
Artigo em Inglês | MEDLINE | ID: mdl-32880564

RESUMO

BACKGROUND: HIV testing rates have increased in recent years. Repeat testing is recommended to identify and treat new HIV infections timeously. However, there are limited data on repeat HIV testing, especially in South Africa (SA). OBJECTIVES: To provide data on repeat HIV testing rates in males and females in a district in SA. METHODS: A sexual and reproductive health (SRH) service integration model was implemented in seven healthcare facilities in eThekwini District, KwaZulu-Natal Province, SA, between 2009 and 2011. HIV testing data were collected from male and female clients attending these facilities, prior to (baseline) and after the implementation (endline) of the 3-year health services integration intervention. RESULTS: There were 230 clients at baseline (195 female, 35 male) and 200 at endline (169 female, 31 male). High ever-tested rates were reported at baseline (females 95.4%, males 74.3%) and endline (females 91.7%, males 87.1%), with large increases in male testing rates over time. In addition, high increases were seen between baseline and endline among those who had tested more than once and more than twice in their lifetime. Increases between baseline and endline testing rates were highest in HIV testing services (HTS) (37.0 - 93.3% for clients who had tested more than once, and 11.1 - 53.3% for those who had tested more than twice). CONCLUSIONS: HIV testing and repeat testing increased over time, especially in males and in HTS. Promotion and integration of SRH services are critical to facilitate improved health-seeking behaviour and HIV testing of both male and female clients. They are also important for continued access to HTS at multiple service delivery points.


Assuntos
Infecções por HIV/diagnóstico , Programas de Rastreamento/estatística & dados numéricos , Serviços de Saúde Reprodutiva , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Infecções por HIV/epidemiologia , Humanos , Masculino , Pessoa de Meia-Idade , Retratamento , África do Sul/epidemiologia
7.
Transplantation ; 19(1): 64-71, 1975 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-1091033

RESUMO

Soluble transplantation antigens were prepared from chacma baboon spleen cell membranes by a modified 3 M KCl technique. The extracts were soluble according to usually accepted criteria. Molecular weight was 37,700 daltons. Antigenicity was confirmed by inhibition of cytotoxicity of alloantibody. The antigens stimulated sensitized lymphocytes in culture but failed to stimulate unsensitized lymphocytes. Antigen-antibody complexes were assembled in vitro in the regions of equivalence and marked antigen excess. Administration of a single dose of soluble donor antigen at the time of orthotopic liver allotransplantation prolonged graft survival significantly. Concomitant administration of a polyspecific alloantibody, previously shown to prolong baboon liver allograft survival, abrogated the graft prolongation produced by the antigen or antibody given alone. When the administration of the soluble antigen was preceded by a dose of cyclophosphamide (20 mg/kg), graft prolongation was slightly curtailed. Antecedent administration of azathioprine and prednisolone for 3 days seemed to render the antigen immunogenic in that liver allograft rejection was accelerated. Antigen-antibody complexes at equivalence prolonged liver allograft survival beyond that seen with antigen alone, but complexes in marked antigen excess were immunogenic, inasmuch as graft survival was not prolonged and the histological features were those of accelerated rejection.


Assuntos
Complexo Antígeno-Anticorpo , Antígenos de Histocompatibilidade , Transplante de Fígado , Imunologia de Transplantes , Transplante Homólogo , Animais , Cromatografia em Gel , Antígenos de Histocompatibilidade/isolamento & purificação , Imunoglobulina G , Lipídeos/isolamento & purificação , Ativação Linfocitária , Linfócitos/imunologia , Peso Molecular , Papio , Proteínas/análise , RNA/isolamento & purificação , Solubilidade , Baço/citologia , Timidina/metabolismo , Trítio
8.
Transplantation ; 26(2): 73-5, 1978 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-80050

RESUMO

This study investigates the possibility that the active enhancing properties of bone marrow (BM) cells may be related to Ia-like determinants on their surface membranes. Less chromium was released on a cell per cell basis from nucleated baboon BM cells used as targets in complement-dependent cytotoxicity than from labelled lymph node lymphocytes. On the other hand, BM cells stimulated allogeneic lymphocytes in culture more vigorously than lymph node lymphocytes. BM cells with lymphocyte-activating properties could be enriched by fractionation on a discontinous bovine serum albumin gradietnt. BM cells responded poorly to allogeneic cell stimulation in mixed culture. Platelet absorption studies of an alloantiserum supported the conclusion that nucleated BM cells, and particularly BM fractions collected from the less dense interfaces of a bovine serum albumin gradient, express relatively more lymphocyte-activating or Ia-like determinants than "serologically defined" determinants.


Assuntos
Medula Óssea/imunologia , Papio/imunologia , Imunologia de Transplantes , Absorção , Animais , Células da Medula Óssea , Proteínas do Sistema Complemento , Epitopos , Sobrevivência de Enxerto , Haplorrinos , Isoanticorpos
9.
Transplantation ; 19(1): 53-9, 1975 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-1091031

RESUMO

Histocompatibility antigens have been solubilised from baboon spleen cell membranes by brief exposure to sodium deoxycholate (DOC). Preparations contained a high molecular weight species (DOCH-Ag) excluded by Sephadex G-200, and a low molecular weight species (DOCL-Ag) which eluted in the included fraction (molecular weight 46,000). The low molecular weight antigen was stable and was not sedimented by high speed centrifugation even after dialysis against a low molar salt solution. It elicited a delayed-type hypersensitivity response in sensitised baboons but not in normal animals. DOCL-Ag cultured in vitro with sensitised allogeneic lymphocytes produced a 1.3- to 24.9-fold stimulation, whereas when cultured with normal lymphocytes the maximum stimulation index was 2. Intravenous administration of donor DOCL-Ag (2 mg/kg) at the time of transplantation and without additional immunosuppression significantly prolonged the mean survival time of baboon liver allografts. The same treatment with donor DOCH-Ag did not prolong graft survival.


Assuntos
Detergentes/farmacologia , Antígenos de Histocompatibilidade , Transplante de Fígado , Imunologia de Transplantes , Animais , Células Cultivadas , Cromatografia em Gel , DNA/análise , Filtração , Hipersensibilidade Tardia/imunologia , Ativação Linfocitária , Linfócitos/imunologia , Papio , Proteínas/análise , RNA/análise , Baço/citologia , Transplante Homólogo , Ultracentrifugação
10.
Transplantation ; 57(7): 1103-10, 1994 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-8165709

RESUMO

Pretransplant conditioning of baboons with total lymphoid irradiation allows long-term renal allograft acceptance in one third of the recipients. Brief additional immunosuppression was given to some animals, but always for less than 14 days after transplant. This enabled us to study mechanisms of graft tolerance in the absence of long-term, nonspecific drug immunosuppression. While 3 patterns of unresponsiveness were noted, this study concentrated on serum-mediated suppression. Eleven of 16 (69%) baboons destined to become tolerant to their grafts developed a nonspecific MLC inhibitory factor in their sera. In most animals it appeared within 3-5 weeks after transplantation and persisted over the period of study (91-793 days after Tx). The suppressor factor was absent in sera from 38 control animals and 8/9 rejectors. It was shown to be a low affinity IgG antibody that inhibited MLC by binding to stimulator cells, an effect that could be overcome by addition of rIL-2 to cultures. NK cell lysis, cell-mediated lympholysis, and polyclonal mitogenesis were unaffected. Antibody binding to purified baboon T cells could not be demonstrated, though binding to EBV-transformed B cells was readily shown. Our study shows that total lymphoid irradiation permits the generation of blocking antibodies directed against APCs as one mechanism of maintaining T cell unresponsiveness. These observations are consistent with the masking of ligands involved in antigen presentation or costimulation leading to a sustained state of autoenhancement.


Assuntos
Anticorpos/sangue , Transplante de Rim/imunologia , Tecido Linfoide/efeitos da radiação , Papio/sangue , Animais , Especificidade de Anticorpos , Ligação Competitiva , Divisão Celular/imunologia , Humanos , Tolerância Imunológica , Interleucina-2/farmacologia , Células Matadoras Naturais/imunologia , Teste de Cultura Mista de Linfócitos , Masculino , Papio/imunologia , Proteínas Recombinantes/farmacologia
11.
Transplantation ; 30(2): 107-10, 1980 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-6451965

RESUMO

After total lymphoid irradiation (TLI), allogeneic bone marrow (BM) injection, and organ transplantation in baboons, there is a prolonged period of reduced lymphocyte proliferative responsiveness to polyclonal mitogens and allogeneic lymphocytes. The effect observed is greater with the use of fractionated TLI than after single doses of irradiation. Suppressor cell activity can be demonstrated in vitro in most animals by inhibition of mixed lymphocyte reactivity (MLR) by mitomycin-treated recipient lymphocytes harvested after TLI, with or without allogeneic BM injection, and organ transplantation. Preliminary data suggest the presence of both donor-specific and nondonor-specific suppression, although other interpretations are possible, and suppressor phenomena may not be responsible for the transplantation tolerance observed.


Assuntos
Transplante de Medula Óssea , Tolerância Imunológica/efeitos da radiação , Sistema Linfático/efeitos da radiação , Linfócitos T Reguladores/imunologia , Animais , Haplorrinos , Transplante de Rim , Transplante de Fígado , Ativação Linfocitária , Teste de Cultura Mista de Linfócitos , Papio/imunologia , Transplante Homólogo
12.
Transplantation ; 29(5): 405-8, 1980 May.
Artigo em Inglês | MEDLINE | ID: mdl-6769185

RESUMO

A modified regimen of fractionated total lymphoid irradiation and allogeneic bone marrow (BM) injection in chacma baboons produced transplantation tolerance for allografted kidneys from the BM donors, and substantial chimerism without evidence of graft-versus-host disease. Increasing the dose of nucleated BM cells injected 4-fold over that used in liver transplantation resulted consistently in normal graft function in the early weeks after transplantation. Bone marrow injection and challenge with renal allografts could be delayed for at least 3 weeks after completion of irradiation. If it can be shown that this period can be extended even further, the protocols will be relevant to the circumstances of clinical cadaveric renal transplantation.


Assuntos
Transplante de Medula Óssea , Sobrevivência de Enxerto/efeitos da radiação , Transplante de Rim , Tecido Linfoide/efeitos da radiação , Animais , Medula Óssea/imunologia , Medula Óssea/efeitos da radiação , Rejeição de Enxerto , Reação Enxerto-Hospedeiro/efeitos da radiação , Haplorrinos , Rim/citologia , Masculino , Papio , Doses de Radiação , Transplante Homólogo
13.
Transplantation ; 52(6): 1072-8, 1991 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-1836285

RESUMO

Predictions of an increasing shortage of donor organs for the future has led to a resurgence of interest in xenotransplantation. We have methodically assessed the immunological compatibility of humans against the chacma baboon with a view to narrowing the gap of concordance by careful immunological screening. The necessity of major blood group compatibility in xenotransplantation is now established. While no group O universal donor exists in the baboon, groups A (45%), B (15%), and AB (40%) are well represented. Baboon histocompatibility antigens could not be precisely defined using human antisera. This does not necessarily imply lack of homology between the species, as we have shown specific crossreactivity of numerous antihuman monoclonal antibodies with baboon leukocytes. Normal humans do not exhibit preformed agglutinins to erythrocytes of the chacma baboon (Papio ursinus orientalis)) but cytotoxic antibodies are occasionally found. Sera from allosensitized patients may contain crossreacting hemagglutinins, leukoagglutinins and complement-dependent cytotoxic antibodies. Binding of human immunoglobulin-G and -M to baboon targets was demonstrated by flow cytometry. Negative crossmatch combinations for antibodies of the IgG subclass were easily found, but IgM antibodies from allosensitized patients were polyspecific in their action. In vitro assessment of lymphocyte mediated cytotoxicity showed that preformed cellular immunity between the species was rare. The response of human lymphocytes to xenoantigen stimulation in mixed lymphocyte cultures showed a normal distribution, permitting the selection of low-responding combinations. Screening for viruses, especially HTLV-1 and Coxsackie-BL34, is important. These findings demonstrate a closer degree of concordance than has previously been suspected.


Assuntos
Antígenos de Histocompatibilidade/imunologia , Papio/imunologia , Animais , Anticorpos Antivirais/análise , Tipagem e Reações Cruzadas Sanguíneas , Reações Cruzadas , Citotoxicidade Imunológica , Hemaglutinação , Antígenos de Histocompatibilidade Classe I/análise , Antígenos de Histocompatibilidade Classe II/análise , Teste de Histocompatibilidade , Vírus Linfotrópico T Tipo 1 Humano/imunologia , Humanos , Imunidade Celular , Teste de Cultura Mista de Linfócitos , Transplante Heterólogo/imunologia
14.
Transplantation ; 36(2): 121-4, 1983 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-6224320

RESUMO

Cyclosporine extends kidney allograft survival in the chacma baboon, and this study explores various administration protocols to generate optimal serum concentrations of the drug, assessed by radioimmunoassay and by inhibition of lymphocyte transformation by phytohemagglutinin and allogeneic lymphocytes in culture. Serum levels commensurate with concentrations that have been shown to be immunosuppressive in humans (150-400 ng/ml) are reached after 14 days of pretreatment with 10 mg cyclosporine/kg, and after 7 days with 20 and 30 mg cyclosporine/kg. The 10-mg dose prolongs median graft survival from 11 to 21 days, which is the same as that obtained with 20 mg/kg administered after transplantation. Further increases in the pretreatment dose to 20 or 30 mg/kg result in survivals of 27 and 31 days, respectively. All the animals died from rejection during therapy and the T-cell-binding avidity, and absorptive or degradative processes may necessitate doses far in excess of those currently used in transplantation.


Assuntos
Ciclosporinas/administração & dosagem , Sobrevivência de Enxerto/efeitos dos fármacos , Transplante de Rim , Absorção , Animais , Ciclosporinas/sangue , Relação Dose-Resposta a Droga , Feminino , Terapia de Imunossupressão/métodos , Ativação Linfocitária/efeitos dos fármacos , Teste de Cultura Mista de Linfócitos , Masculino , Papio , Fito-Hemaglutininas/farmacologia
15.
Transplantation ; 72(6): 1150-2, 2001 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-11579315

RESUMO

BACKGROUND: We previously reported the induction of transplantation tolerance by a modified wide field method of pretransplant total lymphoid irradiation (TLI), cumulative dose 800 cGy, given as 80 or 100 cGy fractions twice/week, in approximately one-third of chacma baboons receiving liver or kidney allografts (1-4) and in vervet monkeys receiving baboon kidney xenografts (5). In this study, the effects of the administration of brief courses of anti-CD3 or CD4-Idarubicin conjugates on the frequency and predictability of tolerance induction by TLI were examined. METHODS: TLI was administered pretransplant in doses of 800, 600, or 400 cGy. The conjugates were administered either after transplantation in doses of 0.25 mg/kg body weight, 3 times/week for 2 weeks, or as a single dose of 1.0 mg/kg body weight 24 hr before transplantation. RESULTS: Operational tolerance, defined as normal graft function >1 year after transplantation, was obtained in one-half of six baboons receiving the single dose of 1 mg/kg of Idarubicin conjugate pretransplant after 800 cGy of TLI and also in one of four baboons treated with 400 cGy of TLI and a single dose of anti-CD3 conjugate before transplantation. By contrast, administration of the conjugated antibodies 3 times/week for 2 weeks after transplantation prevented tolerance induction in all animals, providing further evidence for the involvement of active mechanisms, capable of inhibition by immunosuppressive agents, in tolerance induction with TLI, and of relevance to our reported clinical experience with TLI (6). CONCLUSIONS: These promising findings invite further studies with a larger number of animals and additional brief regimens of irradiation and antibody dosages and specificities.


Assuntos
Antibióticos Antineoplásicos/uso terapêutico , Anticorpos Monoclonais/uso terapêutico , Idarubicina/uso terapêutico , Tolerância Imunológica , Imunotoxinas/uso terapêutico , Transplante de Rim/imunologia , Irradiação Linfática , Animais , Complexo CD3/imunologia , Antígenos CD4/imunologia , Tolerância Imunológica/efeitos dos fármacos , Papio , Cuidados Pós-Operatórios , Cuidados Pré-Operatórios
16.
Transplantation ; 67(6): 864-70, 1999 Mar 27.
Artigo em Inglês | MEDLINE | ID: mdl-10199735

RESUMO

BACKGROUND: The Gal alpha(1,3)Gal epitope is of interest as, in pig-to-primate xenotransplantation, it is the major target of naturally occurring human IgM and IgG antibodies, leading to hyperacute rejection. Human and Old World monkeys make anti-Gal alpha(1,3)Gal antibodies as they lack a functional gene and do not express Gal alpha(1,3)Gal. Interestingly, the cultured fibroblasts of some other species, such as chickens, have been reported also not to express Gal alpha(1,3)Gal--if this is true for other tissues, and chickens do not express Gal alpha(1,3)Gal antigen, then they would have anti-Gal antibodies--which could have diagnostic and therapeutic value, particularly as chicken antibodies do not fix mammalian complement. METHODS: Standard serological methods were used to characterize the antibodies. Several baboons received pig kidney xenografts that had been perfused with hyperimmune chicken anti-Gal antibodies. RESULTS AND CONCLUSIONS: We now demonstrate that chickens do not express Gal alpha(1,3)Gal on their red cells, leukocytes, or tissues, and that their serum contains large amounts of anti-Gal alpha(1,3)Gal antibodies. In addition, chickens could be immunized to produce high-titer, high-avidity antibodies (9.5x10(9) M(-1))--an avidity considerably greater than that of the Gal alpha(1,3)Gal binding lectin IB4 (2.9x10(8) M(-1)) or Gal antibodies in human serum (2.2x10(5) M(-1)). Chicken antibodies, obtained from both normal and immunized chickens, could block the in vitro cytolysis of pig endothelial cells or lymphocytes by human or baboon antibodies. However, such antibodies tested in vivo in pig-to-baboon xenotransplantation failed to block hyperacute rejection and, indeed, may have accelerated this.


Assuntos
Anticorpos/imunologia , Galinhas/imunologia , Dissacarídeos/imunologia , Animais , Afinidade de Anticorpos , Ligação Competitiva , Células COS , Epitopos , Humanos , Imunização , Transplante de Rim , Papio , Suínos
17.
Radiat Res ; 137(1): 84-8, 1994 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-8265791

RESUMO

This study assessed the ability of 11 established and potential radiosensitizing agents to retard the repair of radiation-induced DNA damage with a view to enhancing the immunosuppressive effects of in vivo lymphoid irradiation. The capability of irradiated rat thymocytes to repair DNA damage was assessed by an adaptation of the fluorimetric unwinding method. Three compounds, 3-aminobenzamide (3-AB), novobiocin and flavone-8-acetic acid (FAA), inhibited repair significantly. We also report the effect of low-dose irradiation combined with repair inhibitors on the relationship between DNA strand breaks, fragmentation, cell viability and use of nicotinamide adenine dinucleotide (NAD). DNA fragmentation was increased by 1 mM/1 FAA, 1 mM/l novobiocin and 50 microM/l RS-61443 within 3 h of incubation. The latter two compounds also proved cytotoxic. All three drugs augmented the effect of ionizing radiation on the use of NAD. Of the agents investigated, FAA showed the most promise for augmenting the immunosuppressive action of irradiation at nontoxic, pharmacokinetically achievable concentrations.


Assuntos
Antineoplásicos/farmacologia , Dano ao DNA , Reparo do DNA , Linfócitos T/efeitos da radiação , Animais , Afidicolina/farmacologia , Benzamidas/farmacologia , Citarabina/farmacologia , Reparo do DNA/efeitos dos fármacos , Doxorrubicina/farmacologia , Flavonoides/farmacologia , Raios gama , Cinética , Naftoquinonas/farmacologia , Novobiocina/farmacologia , Radiossensibilizantes/farmacologia , Ratos , Ratos Sprague-Dawley , Linfócitos T/efeitos dos fármacos , Linfócitos T/metabolismo , Fatores de Tempo , Vidarabina/farmacologia
18.
Biophys Chem ; 41(1): 101-10, 1991 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-17014793

RESUMO

The electrolyte concentration and pH dependence of the effective charge density of weak ion exchange membranes have been studied by combining solutions of the Poisson-Boltzmann equation in cylindrical pores with a simple dissociation equilibrium of weakly acid groups attached to the pore walls. Analytical expressions for the effective charge density and wall potential are presented which describe these quantities in terms of pH, electrolyte (1 : 1) concentration, acid constant, density of acid groups and the pore size. The concentration dependence of the effective fixed charge density experimentally observed for cellulose membranes and NaCl-solutions agrees quantitatively with the theoretical predictions. For track-etched mica membranes and KCl-solutions the influence of pH and electrolyte concentration on the effective charge density can be qualitatively explained. Also an interpretation of electro-osmotic findings obtained with an asymmetric cellulose acetate membrane and NaCl-solutions is given.

19.
J Chromatogr A ; 867(1-2): 105-12, 2000 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-10670713

RESUMO

The solution characteristics of beta-LGB (beta-lactoglobulin) and BSA (bovine serum albumin) are reported as determined by size-exclusion chromatography with on-line multiangle laser light scattering, differential refractive index and UV detection. The order of the three in series placed detectors as well as the interdetector volumes have been carefully pointed out. At concentrations below 2.5 mg/ml and at different values of pH the weight-average molecular mass of both proteins have been obtained. They indicate the appearance of monomers, dimers and higher order multimers. For beta-LGB the growth of self-associates could be observed at the isoelectric point over a period of days. The range of applicability of the method is discussed.


Assuntos
Cromatografia em Gel/métodos , Lactoglobulinas/análise , Soroalbumina Bovina/análise , Biopolímeros , Lasers , Espalhamento de Radiação , Cloreto de Sódio , Soluções , Espectrofotometria Ultravioleta , Água
20.
Scand J Immunol Suppl ; 11: 176-8, 1992.
Artigo em Inglês | MEDLINE | ID: mdl-1381108

RESUMO

TLI has potent immunosuppressive effects, but there is concern over its possible carcinogenic properties. The aim of the study was to assess to what degree TLI may compromise natural killer (NK) and lymphokine activated killer (LAK) cell function. There was a significant increase (P less than 0.0001) in both NK-cell function (measured against K562 targets) and spontaneous LAK-cell function (measured against DAUDI targets) in fresh blood lymphocytes throughout a course of 8 x 100 cGy fractionated TLI. This may be related to a three- and sevenfold increase, respectively, in CD16+ CD8- and CD56+ CD2- cell frequencies over the same period. Mitogen-induced interleukin 2 (IL-2) synthesis from blood lymphocytes was inhibited by up to 75% with as little as 100 cGy of TLI. Expression of IL-2 receptors on fresh lymphocytes did not vary and remained low. Therefore spontaneous LAK occurrence appeared to be triggered through an IL-2-independent pathway. The in vitro addition of IL-2 verified that cells retained their ability to respond to this lymphokine resulting in greatly enhanced induced LAK function. This was most probably mediated by CD56+ cells which were found to readily express IL-2 receptors upon mitogen stimulation. In conclusion, fractionated low-dose TLI appears to enhance MHC unrestricted immune surveillance in a manner independent of IL-2 production.


Assuntos
Células Matadoras Ativadas por Linfocina/efeitos da radiação , Tecido Linfoide/efeitos da radiação , Animais , Antígenos CD/análise , Antígenos de Diferenciação de Linfócitos T/análise , Antígeno CD56 , Interleucina-2/fisiologia , Células Matadoras Ativadas por Linfocina/fisiologia , Papio , Receptores de Interleucina-2/análise
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