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1.
Hum Vaccin Immunother ; 16(7): 1511-1520, 2020 07 02.
Artigo em Inglês | MEDLINE | ID: mdl-31977285

RESUMO

This study engaged health professionals in in-depth, semi-structured interviews to explore their opinions concerning the issues surrounding vaccine hesitancy in Malaysia and strategies to improve vaccination to stamp the rise of vaccine preventable diseases (VPDs). Opinions on how to address the resurgence of VPDs in the era of increasing vaccine hesitancy were obtained. Eight health professionals, including geriatricians, pediatricians, microbiologists, public health specialists, and family medicine specialists were interviewed. The influence of anti-vaccination propaganda, past-experience of adverse event following immunization (AEFI), perceived religious prohibition, a belief that traditional complementary and alternative medicine (TCAM) use is safer, pseudoscience beliefs, and anti-vaccine conspiracy theories were identified as reasons for refusing to vaccinate. The interplay of social, cultural and religious perspectives in influencing perceived religious prohibition, pseudoscience beliefs, and the use of TCAM contributing to vaccine refusal was found. Five broad themes emerged from the health professionals regarding strategies to address vaccine hesitancy, including establishing an electronic vaccination registry, increasing public awareness initiatives, providing feedback to the public on the findings of AEFI, training of front-line healthcare providers, and banning the dissemination of anti-vaccine information via social media. With regards to identifying strategies to address the resurgence of VPDs, mandatory vaccination received mixed opinions; many viewed supplementary immunization activity and the prevention of travel and migration of unvaccinated individuals as being necessary. In conclusion, the present study identified unique local cultural, traditional and religious beliefs that could contribute to vaccine hesitancy in addition to issues surrounding vaccination refusal similarly faced by other countries around the world. This information are important for the formulation of targeted intervention strategies to stamp vaccine hesitancy in Malaysia which are also a useful guide for other countries especially in the Southeast Asia region facing similar vaccine hesitancy issues.


Assuntos
Doenças Preveníveis por Vacina , Vacinas , Conhecimentos, Atitudes e Prática em Saúde , Humanos , Malásia , Aceitação pelo Paciente de Cuidados de Saúde , Vacinação , Recusa de Vacinação
2.
Sex Transm Dis ; 46(9): 617-624, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31181035

RESUMO

BACKGROUND: The aim of this study was to investigate factors associated with the willingness of boys to accept the human papillomavirus (HPV) vaccine. METHODS: A nationwide cross-sectional survey among Secondary One male students in Malaysia. RESULTS: Among 2823 respondents, knowledge about HPV infection and the HPV vaccine was extremely poor. The mean total knowledge score was only 3.17 (SD ± 2.14), out of a possible score of 10. The majority of respondents were unaware that vaccinating boys can help protect girls against HPV infection (81.6%), and HPV is a sexually transmitted infection (70.1%). Many had the misconception that only females get HPV (78.9%). In multivariable analysis, the factors associated with the intention to receive the HPV vaccination were: agreeing boys need to be vaccinated against HPV infection (odds ratio [OR], 2.05; 95% confidence interval [CI], 1.57-2.68), perceiving their parents might allow them to get the HPV vaccine (OR, 1.66; 95% CI, 1.18-2.34), perceived susceptibility to HPV infection (OR, 1.63; 95% CI, 1.06-2.52), and attending a rural school (OR, 1.49; 95% CI, 1.14-1.95). CONCLUSIONS: Public health educational programs that are focused and tailored on parents consenting to HPV vaccination for boys at a young age can be useful in improving HPV vaccination rates among boys. There is also a pressing need to educate boys about the benefits of HPV vaccination in males and about HPV disease susceptibility to facilitate adoption of the HPV vaccine by young adults in the future.


Assuntos
Conhecimentos, Atitudes e Prática em Saúde , Infecções por Papillomavirus/prevenção & controle , Vacinas contra Papillomavirus/administração & dosagem , Aceitação pelo Paciente de Cuidados de Saúde , Estudantes/estatística & dados numéricos , Vacinação/psicologia , Adolescente , Estudos Transversais , Humanos , Malásia , Masculino , Instituições Acadêmicas , Inquéritos e Questionários , Vacinação/estatística & dados numéricos
3.
Int Nurs Rev ; 65(2): 200-208, 2018 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-29430644

RESUMO

AIM: To examine the factors associated with nurses' perceptions of the quality of end-of-life care. BACKGROUND: With increasing demand for hospitals to provide end-of-life care, the low quality of palliative care provided in hospital settings is an issue of growing concern in developing countries. Most dying patients receive their care from general nurses, irrespective of the nurses' specialty or level of training. METHOD: A structured cross-sectional questionnaire survey was conducted of 553 nurses working at a teaching hospital in Malaysia. RESULTS: The mean scores for nurses' knowledge about end-of-life care, their attitudes towards end-of-life care and the perceived quality of end-of-life care were low. The factors identified as significantly associated with the quality of end-of-life care were nurses' levels of knowledge and their attitudes towards end-of-life care. DISCUSSION: Factors that contributed to the low quality of end-of-life care were inadequate knowledge and negative attitudes. These findings may reflect that end-of-life care education is not well integrated into nursing education. CONCLUSION: The findings of this study suggest that there is a need to increase the nurses' level of knowledge and improve their attitude towards end-of-life care in order to enhance the quality of care provided to dying patients. IMPLICATIONS FOR NURSING AND HEALTH POLICY: Nurse managers and hospital policymakers should develop strategies to enhance nurses' level of knowledge, as well as providing adequate emotional support for nurses who care for dying patients and their families. Nurses should be proactive in increasing their knowledge and adopting more positive attitudes towards end-of-life care.


Assuntos
Papel do Profissional de Enfermagem/psicologia , Relações Enfermeiro-Paciente , Recursos Humanos de Enfermagem Hospitalar/psicologia , Assistência Terminal/psicologia , Adulto , Atitude Frente a Morte , Feminino , Conhecimentos, Atitudes e Prática em Saúde , Humanos , Malásia , Masculino , Pessoa de Meia-Idade , Qualidade da Assistência à Saúde , Adulto Jovem
4.
Int Nurs Rev ; 61(3): 352-60, 2014 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-24902878

RESUMO

AIM: The purpose of this qualitative descriptive study was to explore factors related to critical care and medical-surgical nurses' job satisfaction as well as dissatisfaction in Iran. BACKGROUND: Job satisfaction is an important factor in healthcare settings. Strong empirical evidence supports a causal relationship between job satisfaction, patient safety and quality of care. METHOD: A convenient sample of 85 nurses from surgical, medical and critical care wards of a large hospital was recruited. Ten focus group discussions using a semi-structured interview guide were conducted. Interviews were audio-recorded, transcribed verbatim and analysed using a thematic approach. FINDINGS: The study identified three main themes that influenced nurses' job satisfaction and dissatisfaction: (1) spiritual feeling, (2) work environment factors, and (3) motivation. Helping and involvement in patient care contributed to the spiritual feeling reported to influence nurses' job satisfaction. For work environment factors, team cohesion, benefit and rewards, working conditions, lack of medical resources, unclear nurses' responsibilities, patient and doctor perceptions, poor leadership skills and discrimination at work played an important role in nurses' job dissatisfaction. For motivation factors, task requirement, professional development and lack of clinical autonomy contributed to nurses' job satisfaction. CONCLUSION AND IMPLICATIONS FOR NURSING AND HEALTH POLICY: Nurse managers should ensure a flexible practice environment with adequate staffing and resources with opportunities for nurses to participate in hospital's policies and governance. Policy makers should consider nurses' professional development needs, and implement initiatives to improve nurses' rewards and other benefits as they influence job satisfaction.


Assuntos
Cuidados Críticos/organização & administração , Satisfação no Emprego , Motivação , Recursos Humanos de Enfermagem Hospitalar/organização & administração , Recursos Humanos de Enfermagem Hospitalar/psicologia , Enfermagem Perioperatória/organização & administração , Espiritualidade , Adulto , Atitude do Pessoal de Saúde , Feminino , Grupos Focais , Humanos , Irã (Geográfico) , Masculino , Pessoa de Meia-Idade , Cultura Organizacional , Segurança do Paciente , Percepção , Qualidade da Assistência à Saúde , Salários e Benefícios , Desenvolvimento de Pessoal , Adulto Jovem
5.
Water Sci Technol ; 64(12): 2439-44, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-22170839

RESUMO

Conventional aerobic and low-rate anaerobic processes such as pond and open-tank systems have been widely used in wastewater treatment. In order to improve treatment efficacy and to avoid greenhouse gas emissions, conventional treatment can be upgraded to a high performance anaerobic granular-sludge system. The anaerobic granular-sludge systems are designed to capture the biogas produced, rendering a potential for claims of carbon credits under the Kyoto Protocol for reducing emissions of greenhouse gases. Certified Emission Reductions (CERs) would be issued, which can be exchanged between businesses or bought and sold in international markets at the prevailing market prices. As the advanced anaerobic granular systems are capable of handling high organic loadings concomitant with high strength wastewater and short hydraulic retention time, they render more carbon credits than other conventional anaerobic systems. In addition to efficient waste degradation, the carbon credits can be used to generate revenue and to finance the project. This paper presents a scenario on emission avoidance based on a methane recovery and utilization project. An example analysis on emission reduction and an overview of the global emission market are also outlined.


Assuntos
Conservação de Recursos Energéticos/métodos , Efeito Estufa , Resíduos Industriais/análise , Óleos de Plantas/química , Eliminação de Resíduos Líquidos/métodos , Poluentes Químicos da Água/química , Poluentes Atmosféricos/química , Anaerobiose , Carbono/química , Óleo de Palmeira , Esgotos
7.
Southeast Asian J Trop Med Public Health ; 42(5): 1119-29, 2011 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-22299438

RESUMO

Globally, HIV/AIDS-related stigma and discriminatory attitudes deter the effectiveness of HIV prevention and care programs. This study investigated the general public's perceptions about HIV/AIDS-related stigma and discrimination towards people living with or affected by HIV/AIDS in order to understand the root of HIV/AIDS-related stigma and discriminatory attitudes. Study was carried out using qualitative focus group discussions (FGD). An interview guide with semi-structured questions was used. Participants were members of the public in Malaysia. Purposive sampling was adopted for recruitment of participants. A total 14 focus group discussions (n = 74) was carried out between March and July 2008. HIV/AIDS-related stigma and discrimination towards people living with HIV/AIDS (PLWHA) was profound. Key factors affecting discriminatory attitudes included high-risk taking behavior, individuals related to stigmatized identities, sources of HIV infection, stage of the disease, and relationship with an infected person. Other factors that influence attitudes toward PLWHA include ethnicity and urban-rural locality. Malay participants were less likely than other ethnic groups to perceive no stigmatization if their spouses were HIV positive. HIV/AIDS-related stigma and discrimination were stronger among participants in rural settings. The differences indicate attitudes toward PLWHA are influenced by cultural differences.


Assuntos
Infecções por HIV/psicologia , Conhecimentos, Atitudes e Prática em Saúde/etnologia , Preconceito , Estigma Social , Grupos Focais , Amigos , Infecções por HIV/prevenção & controle , Infecções por HIV/transmissão , Humanos , Transmissão Vertical de Doenças Infecciosas , Malásia , Estado Civil , Pesquisa Qualitativa , Assunção de Riscos , População Rural , Abuso de Substâncias por Via Intravenosa , Sexo sem Proteção , População Urbana
8.
Singapore Med J ; 51(10): 790-5, 2010 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-21103814

RESUMO

INTRODUCTION: This study assessed the information needs, preferred educational messages and channels of delivery, as well as opinions on strategies to promote organ donation. It aimed to provide insight into a culturally sensitive public education campaign to encourage organ donation in diverse ethnic communities in Asia, namely the Malays, Chinese and Indians. METHODS: A total of 17 focus group discussions with 105 participants were conducted between September and December 2008. The participants were members of the general public aged 18 to 60 years, who were recruited through convenient sampling in the Klang Valley area of Malaysia. RESULTS: Across ethnic groups, there was a general concern about the mistreatment of the deceased's body in the organ procurement process. The Chinese and Indian participants wanted assurance that the body would be treated with respect and care. The Muslims wanted assurance that the handling of a Muslim's body would follow the rules and regulations of the Islamic faith. The most important information requested by the Muslim participants was whether cadaveric donation is permissible in Islam. A lack of national public education and promotion of organ donation was noted. All the three ethnic groups, especially the Malays, required community and religious leaders for support, encouragement and involvement, as sociocultural influences play a significant role in the willingness to donate organs. CONCLUSION: The pronounced ethnic differences in information needs suggest that culturally sensitive public educational messages are required. Organ donation and transplantation organisations should work closely with community and religious organisations to address the sociocultural barriers identified.


Assuntos
Doadores de Tecidos/educação , Adolescente , Adulto , Cadáver , Características Culturais , Etnicidade , Feminino , Grupos Focais , Conhecimentos, Atitudes e Prática em Saúde , Humanos , Islamismo , Malásia , Masculino , Pessoa de Meia-Idade , Educação de Pacientes como Assunto/métodos , Religião , Obtenção de Tecidos e Órgãos
9.
Transplant Proc ; 42(5): 1439-44, 2010 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-20620450

RESUMO

BACKGROUND: In-depth understanding of cultural and religious factors limiting organ donation of three ethnic populations (Malay, Chinese, and Indian) in Southeast Asia is lacking. Identification of factors limiting organ donation among these three ethnic groups will provide insights into culturally appropriate strategies to promote acceptance of organ donation in a multiethnic Asian community. METHODS: A total of 17 focus group discussions (105 participants) were conducted between September and December 2008. Participants were members of the general public aged 18 to 60 years, recruited through convenient sampling around the Klang Valley area of Malaysia. RESULTS: Although the majority had favorable attitudes toward deceased organ donation and transplantation, a diversity of myths and misinformation were unearthed from the discussions across the ethnic groups. These include perceived religious prohibition, cultural myths and misperceptions, fear of disfigurement, fear of surgery, distrust of the medical system, and family disapproval. Culture and religious beliefs played important prohibitive roles among those opposed to organ donations. There were distinctive ethnic differences in cultural and religious concerns regarding organ donation. Less-educated and rural groups appeared to have more misconceptions than the well-educated and the urban groups. CONCLUSION: Our findings may assist organ donation and transplantation organizations to reach diverse sociodemographic and ethnic communities with culture-specific information about organ donation. The involvement of community and religious leaders is critical in organ donation requests.


Assuntos
Diversidade Cultural , Obtenção de Tecidos e Órgãos/estatística & dados numéricos , Adolescente , Adulto , Países em Desenvolvimento , Escolaridade , Etnicidade , Feminino , Humanos , Renda , Malásia , Masculino , Pessoa de Meia-Idade , Obtenção de Tecidos e Órgãos/métodos , Adulto Jovem
12.
Singapore Med J ; 50(1): 49-53, 2009 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-19224084

RESUMO

INTRODUCTION: Cervical cancer is one of the commonest cancers in women worldwide. Despite the existence of effective screening using Pap smear, the uptake of screening is poor. A qualitative study was undertaken using face-to-face in-depth interviews to investigate knowledge, attitudes and beliefs on cervical cancer screening of Malaysian women. METHODS: In-depth interviews were conducted with 20 Malaysian women aged 21-56 years and who have never had a Pap smear test, with the aim to explore their knowledge and awareness of cervical cancer and its screening. RESULTS: A lack of knowledge on cervical cancer and the Pap smear test was found among the respondents. Many women did not have a clear understanding of the meaning of an abnormal cervical smear and the need for the early detection of cervical cancer. Many believe the purpose of the Pap smear test is to detect existing cervical cancer, leading to the belief that Pap smear screening is not required because the respondents had no symptoms. Despite considerable awareness of a link between cervical cancer and sexual activity, as well as the role of a sexually-transmitted infection, none of the respondents had heard of the human papillomavirus. CONCLUSION: The findings highlight the importance of emphasising accurate information about cervical cancer and the purpose of Pap smear screening when designing interventions aimed at improving cervical cancer screening for Malaysian women.


Assuntos
Conhecimentos, Atitudes e Prática em Saúde , Teste de Papanicolaou , Neoplasias do Colo do Útero/prevenção & controle , Esfregaço Vaginal , Adulto , Detecção Precoce de Câncer , Feminino , Humanos , Entrevistas como Assunto , Malásia , Pessoa de Meia-Idade
13.
Hugo J ; 3(1-4): 63-76, 2009 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-20535403

RESUMO

Breast cancers related to BRCA mutations are associated with particular biological features. Here we report the clinical and pathological characteristics of breast cancer in Chinese women with and without BRCA mutations and of carriers of BRCA1 mutations compared to BRCA2 mutations. Two hundred and 26 high-risk Hong Kong Chinese women were tested for BRCA mutations, medical information was obtained from medical records, and risk and demographic information was obtained from personal interviews. In this cohort, 28 (12.4%) women were BRCA mutation carriers and among these carriers, 39.3% were BRCA1 and 60.7% were BRCA2 mutations. Mutation carriers were more likely to have a familial history of breast and ovarian cancer, high-grade cancers, and triple negative (TN) cancers. Prevalence of TN was 48.3% in BRCA carriers and 25.6% in non-carriers and was 67.7% in BRCA1 and 35.3% in BRCA2 carriers. Estrogen receptor (ER) negative cancer was significantly associated with BRCA1 mutations, especially in those under 40 years of age. BRCA-related breast cancer in this Chinese population is associated with family history and adverse pathological/prognostic features, with BRCA2 mutations being more prevalent but BRCA1 carriers having more aggressive and TN cancers. Compared to Caucasian populations, prevalence of BRCA2 mutations and TN cancer in BRCA2 mutation carriers in Chinese population are elevated.

14.
Int J Behav Med ; 15(4): 289-92, 2008.
Artigo em Inglês | MEDLINE | ID: mdl-19005928

RESUMO

BACKGROUND: Attitudes toward cervical cancer and participation in early detection and screening services are well known to be profoundly affected by cultural beliefs and norms. PURPOSE: This study explored the attitudes and sociocultural beliefs on cervical cancer screening among Malaysian women. METHOD: In this qualitative study, in-depth interviews were conducted with 20 Malaysian women, ages 21 to 56 years, who have never had a Papanicolaou (Pap) smear. RESULTS: Respondents generally showed a lack of knowledge about cervical cancer screening using Pap smear, and the need for early detection for cervical cancer. Many believed the Pap smear was a diagnostic test for cervical cancer, and since they had no symptoms, they did not go for Pap screening. Other main reasons for not doing the screening included lack of awareness of Pap smear indications and benefits, perceived low susceptibility to cervical cancer, and embarrassment. Other reasons for not being screened were related to fear of pain, misconceptions about cervical cancer, fatalistic attitude, and undervaluation of own health needs versus those of the family. CONCLUSION: Women need to be educated about the benefits of cervical cancer screening. Health education, counseling, outreach programs, and community-based interventions are needed to improve the uptake of Pap smear in Malaysia.


Assuntos
Comparação Transcultural , Conhecimentos, Atitudes e Prática em Saúde , Programas de Rastreamento/psicologia , Teste de Papanicolaou , Neoplasias do Colo do Útero/etnologia , Neoplasias do Colo do Útero/prevenção & controle , Esfregaço Vaginal/psicologia , Adulto , Ansiedade/psicologia , Cultura , Feminino , Identidade de Gênero , Educação em Saúde , Humanos , Malásia , Pessoa de Meia-Idade , Aceitação pelo Paciente de Cuidados de Saúde/psicologia , Neoplasias do Colo do Útero/psicologia , Adulto Jovem
15.
Singapore Med J ; 49(3): 256-60; quiz 261, 2008 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-18363011

RESUMO

Focus group discussion is a research methodology in which a small group of participants gather to discuss a specified topic or an issue to generate data. The main characteristic of a focus group is the interaction between the moderator and the group, as well as the interaction between group members. The objective is to give the researcher an understanding of the participants' perspective on the topic in discussion. Focus groups are rapidly gaining popularity in health and medical research. This paper presents a general introduction of the use of focus groups as a research tool within the context of health research, with the intention of promoting its use among researchers in healthcare. A detailed methodology for the conduct of focus groups and analysis of focus group data are discussed. The potentials and limitations of this qualitative research technique are also highlighted.


Assuntos
Pesquisa Biomédica/métodos , Grupos Focais/métodos , Humanos , Seleção de Pacientes , Pesquisa Qualitativa
16.
Fam Cancer ; 7(2): 125-33, 2008.
Artigo em Inglês | MEDLINE | ID: mdl-17657584

RESUMO

INTRODUCTION: Germline mutations of BRCA1 and BRCA2 account for the majority of hereditary breast cancers, many of which are classified as variants of unknown significance (VUS). We report the identification of a novel BRCA2 variant (c.7806-9T > G) in a Chinese family with multiple breast cancers and document it as a pathogenic mutation. METHODS: The proband in this family was diagnosed with breast cancer at age 50 with a strong family history of breast cancer. DNA and RNA were extracted from the blood of the proband and her family, and was used for BRCA gene mutation/deletion screening and RNA splicing analysis. RESULTS: BRCA2 c.7806-9T > G was identified in the proband, which was suggestive of a variant. This change was also found in two sisters of the proband with a history of breast cancer, as well as from the proband's maternal gastric cancer. The only sibling free of breast cancer did not carry the BRCA2 variant, thus demonstrating that the mutation segregates with the clinical phenotype in this family. RNA analysis on the proband blood sample revealed three aberrant splicing variants: c.7806_7874del, c.7806_7976del, and c.7806-8_7806-1ins. The latter causes a frameshift and creates a truncated protein, whilst the other two splicing variants resulted in shorter forms of the protein. CONCLUSIONS: The identified BRCA2 c.7806-9T > G [Genbank: DQ889340] was found to be pathogenic, based on aberrant splicing events resulting in the formation of truncated protein products. Thus, better understanding and classification of BRCA variants as neutral or disease causing has important implications for genetic counseling so that appropriate management can be given.


Assuntos
Povo Asiático/genética , Neoplasias da Mama/genética , Genes BRCA2 , Mutação , Adulto , Sequência de Bases , Neoplasias da Mama/patologia , Feminino , Genes BRCA1 , Mutação em Linhagem Germinativa , Humanos , Pessoa de Meia-Idade , Linhagem , Mutação Puntual , Fatores de Risco , Análise de Sequência de DNA
17.
Br J Clin Pharmacol ; 58(3): 332-5, 2004 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-15327595

RESUMO

AIMS: Impaired S-mephenytoin 4'-hydroxylation is a well-described genetic polymorphism affecting drug metabolism in humans. Although ethnic differences in its distribution of polymorphism has been described, it is not known whether there is an ethnic heterogeneity of the structure and expression of the CYP2C19 enzyme in the Malaysian population. METHODS: Study subjects were 142 healthy, unrelated Malaysians aged 18-29 years. Baseline omeprazole and 2-h postingestion omeprazole and 5'-hydroxyomeprazole concentrations were measured for CYP2C19 phenotype determination. Identification of CYP2C19 genotypes was performed with the use of polymerase chain reaction. RESULTS: Phenotyping of CYP2C19 revealed that the prevalence of poor metabolizers (PMs) in the Malaysian population was 14.1%, whereas prevalence of PMs in genotyping was 12.6%. The PM genotypic prevalence rate was 5.6% in Malays, 19.1% in Chinese and 10.0% in Indian subjects. There were significant differences in PM genotypic prevalence rates among the three primary ethnic groups (P < or = 0.05). CONCLUSIONS: Phenotyping and genotyping revealed significant differences in the prevalence rates among the three ethnic groups in Malaysia, with Chinese recording highest prevalence.


Assuntos
Hidrocarboneto de Aril Hidroxilases/genética , Oxigenases de Função Mista/genética , Omeprazol/análogos & derivados , Polimorfismo Genético/genética , 2-Piridinilmetilsulfinilbenzimidazóis , Adolescente , Adulto , Citocromo P-450 CYP2C19 , Feminino , Frequência do Gene , Humanos , Malásia , Masculino , Omeprazol/metabolismo , Fenótipo , Reação em Cadeia da Polimerase
19.
Vaccine ; 19(20-22): 2945-54, 2001 Apr 06.
Artigo em Inglês | MEDLINE | ID: mdl-11282206

RESUMO

A novel vaccine for hepatitis B virus (HBV) was designed by putting a naked DNA vaccine carrying hepatitis B surface antigen (HBsAg) into live-attenuated Salmonella typhimurium. Mucosal immunization by the oral route in mice showed significantly stronger cytotoxic T lymphocyte (CTL) response than recombinant HBsAg vaccination (P < 0.01 at an effector:target ratio of 100:1), while comparable to intramuscular naked DNA immunization at all effector:target ratios. Contrary to previous reports on naked DNA vaccines given intramuscularly, the IgG antibody response induced by the mucosal DNA vaccine is relatively weak when compared to recombinant HBsAg vaccine (P < 0.001 at day 21). These findings are supported by a high interferon-gamma but a low interleukin-4 level detected in the supernatant of splenic cell cultures obtained from mucosally immunized mice. As distinct to recombinant HBsAg vaccine which is effective for protection, oral mucosal DNA vaccine should be considered as a candidate for therapeutic immunization in chronic HBV infection, donor immunization before adoptive transfer of HBV-specific CTL to HBsAg positive bone marrow transplant recipients, and immunization of non-responders to recombinant HBsAg vaccine. This strongly cellular and relatively absent humoral response may make this vaccine a better candidate as a therapeutic vaccine for chronic HBV carriers than naked DNA vaccines, as the humoral response is relatively less important for the clearance of HBV from hepatocytes, but its presence may lead to side effects such as serum sickness and immune complex deposition in chronic HBV carriers.


Assuntos
Antígenos de Superfície da Hepatite B/imunologia , Vacinas contra Hepatite B/imunologia , Salmonella typhimurium/genética , Vacinas de DNA/imunologia , Vacinas Sintéticas/imunologia , Animais , Feminino , Antígenos de Superfície da Hepatite B/genética , Interferon gama/biossíntese , Interleucina-4/biossíntese , Camundongos , Camundongos Endogâmicos BALB C , Salmonella typhimurium/imunologia , Linfócitos T Citotóxicos/imunologia , Transfecção , Vacinas Atenuadas/imunologia
20.
Clin Diagn Lab Immunol ; 7(4): 596-9, 2000 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-10882658

RESUMO

Live-attenuated Salmonella species are effective carriers of microbial antigens and DNA vaccines. In a mouse model, the immunoglobulin M (IgM) and total antibody levels directed toward the lipopolysaccharide of Salmonella enterica serovar Typhi were significantly enhanced at day 21 after oral immunization with live-attenuated serovar Typhi (strain Ty21a) when ampicillin was concomitantly administered (P < 0.05 and P < 0.005, respectively). The heat-killed Ty21a-stimulated lymphocyte proliferation indices for the ampicillin group at day 21 were significantly higher than those for the normal saline (NS) group (P < 0.005, P < 0.001, and P < 0.01) for all three doses of antigen (10(4), 10(5), and 10(6) heat-killed Ty21a per well, respectively). The 50% lethal doses for mice from the ampicillin and NS groups immunized with Ty21a with pBR322 after wild-type serovar Typhi challenge on day 24 were 3.4 x 10(7) and 5.0 x 10(6) CFU, respectively. The fecal bacterial counts for the ampicillin group at days 1, 3, and 5 were significantly lower than those for the NS group (P < 0.01, P < 0.01, and P < 0.05, respectively), and there was a trend toward recovery of Ty21a in a larger number of mice from the ampicillin group than from the NS group. Furthermore, the IgG2a levels directed toward tetanus toxoid were significantly enhanced at days 7 and 21 after oral immunization with Ty21a that carried the fragment c of tetanus toxoid when ampicillin was concomitantly administered (P < 0.05 and P < 0.005, respectively), and the IgM and total hepatitis B surface antibody levels were significantly enhanced at days 7 (P < 0.005 and P < 0.05, respectively) and 21 (P < 0.01 and P < 0.05, respectively) after oral immunization with Ty21a that carried the DNA vaccine that encodes hepatitis B surface antigen when ampicillin was concomitantly administered. The present observation may improve the efficacy of the protein antigens and DNA vaccines carried in live-attenuated bacteria, and further experiments should be carried out to determine the best antibiotics and dosage regimen to be used, as well as the best carrier system for individual protein antigens and DNA vaccines.


Assuntos
Ampicilina/farmacologia , Anticorpos Antibacterianos/imunologia , Antígenos de Bactérias/imunologia , Penicilinas/farmacologia , Salmonella enterica/imunologia , Vacinas de DNA/imunologia , Animais , Anticorpos Antibacterianos/biossíntese , Feminino , Camundongos , Camundongos Endogâmicos BALB C
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