RESUMO
Compatible organic osmolytes, such as betaine, myoinositol, and taurine, are involved in antioxidant defense, protein stabilization, and stress responses. This osmolyte strategy requires the expression of specific osmolyte transporters such as betaine (BGT-1), myoinositol (SMIT), and taurine (TAUT). In contrast to the kidney, keratinocytes, and neural cells, few studies have examined osmolytes in human lens epithelial cells (HLECs). We examined the expression of mRNA specific for BGT-1, SMIT, and TAUT in HLECs. In comparison to normoosmotic (305 mOsM) controls, there was a 3-5-fold time-dependent reaction of BGT-1, SMIT, and TAUT mRNA levels in HLECs exposed to hyperosmotic stress (405 mOsM). Maximal responses were obtained for BGT-1, SMIT, and TAUT mRNA expression after 3, 24 and 9 h of hyperosmotic exposure, respectively. This expression was correlated with increased osmolyte uptake. In contrast, hypoosmotic (205 mOsM) stimulation led to a significant efflux of osmolytes. Exposure to ultraviolet A (340-400 nm) radiation significantly stimulated osmolyte uptake. Increased osmolyte uptake was associated with upregulation of mRNA steady-state levels for osmolyte transporters in irradiated cells. These results demonstrate that ultraviolet A radiation leads to the accumulation of compatible organic osmolytes in HLECs as hyperosmotic pressure, which can maintain cellular environmental homeostasis.
Assuntos
Proteínas de Transporte/genética , Células Epiteliais/efeitos da radiação , Proteínas de Choque Térmico/genética , Cristalino/efeitos da radiação , Glicoproteínas de Membrana/genética , Proteínas de Membrana Transportadoras/genética , RNA Mensageiro/genética , Simportadores/genética , Betaína/metabolismo , Transporte Biológico/efeitos da radiação , Proteínas de Transporte/metabolismo , Linhagem Celular , Células Epiteliais/citologia , Células Epiteliais/metabolismo , Proteínas da Membrana Plasmática de Transporte de GABA , Expressão Gênica , Proteínas de Choque Térmico/metabolismo , Humanos , Inositol/metabolismo , Cristalino/citologia , Cristalino/metabolismo , Glicoproteínas de Membrana/metabolismo , Proteínas de Membrana Transportadoras/metabolismo , Concentração Osmolar , Pressão Osmótica , RNA Mensageiro/metabolismo , Simportadores/metabolismo , Taurina/metabolismo , Raios UltravioletaRESUMO
AIM: To identify the forms and means of emotional support that nurses provide to patients living with multidrug-resistant tuberculosis (MTR-TB) in Lima, Peru. BACKGROUND: A fundamental role of nurses is to provide emotional support, defined as all the strategies that a health team employs to assure the psychosocial well-being of the patient. However, neither the forms of emotional support nor the means used by nurses in resource-poor settings have been much written about. This paper describes a qualitative study of a team of seven nurses working in a programme that provides individualized MDR-TB treatment to patients in Lima, Peru. It describes the various forms of support that facilitated the ability of patients to adhere to treatment despite socio-economic difficulties, social stigma, drug side effects, problems related to different stages of treatment and concurrent illnesses/special situations. METHODS: Qualitative study methods were employed over the course of 8 years to observe nurses and patients in an MDR-TB treatment programme. These included participant observation, structured observation sessions of nurses with their patients and focus groups with seven nurses. CONCLUSION: Through theme and content analyses of qualitative data, ten situations related to MDR-TB treatment were found. These ten issues served as an analytical framework used to identify and discuss the various types of emotional support provided by both formal and informal means. This type of support focused on problems related to different stages of treatment, social stigma of the illness, treatment adherence, side effects, socio-economic difficulties, death and concurrent illnesses/special situations. PRACTICE IMPLICATIONS: The essential role of the nurse as a provider of emotional support in the development or implementation of similar programmes with MDR-TB should, in future, be taken into account.