RESUMO
Objective: To ascertain the knowledge levels, attitudes and beliefs towards organ donation by relatives of patients in the Intensive Care Unit at two tertiary care hospitals in Trinidad. Design and Methodology: A descriptive study in which researchers'-designed and pretested self-administered questionnaire was used on a sample of 133 randomly selected patients' relatives from two main intensive care hospital units in Trinidad. The respondents were requested to give their consent after necessary ethical approval was received. Data entry was done manually but the analysis was done with the SPSS version 12 programme. Results were presented as frequencies. Results: Demographic characteristics indicated that most were females, of African ethnicity, and Christianity as their main religion. The majority of participants had a high level of knowledge (69.2%) while 57.9% of them had unfavourable attitude towards organ donation. Most (86.5%) had positive belief. It also showed that the respondents' knowledge towards organ donation is significantly related to their age and religion, (P≤, 0.05) while their attitudes are significantly related to their gender and ethnicity (p≤0.05). Their belief was only significantly associated with their marital status. Conclusion: The study has shown that although patients' relatives in Trinidad have general knowledge of organ donation, as well positive belief towards the practice, their attitudes are mostly unfavourable. We believe that their attitude more than their knowledge and beliefs account more for their actions towards organ donation.
Assuntos
Humanos , Masculino , Feminino , Obtenção de Tecidos e Órgãos , Trinidad e TobagoRESUMO
Minute-by-minute net water fluxes (Jw) were measured across the isolated rectal epithelium in rats and rabbits. Five minutes after a serosal (but not mucosal) hypertonic challenge (plus 200 mosmol/l) a significant increase in the basal Jw was recorded in both species [deltaJw, microl min(-1) cm(-2): 0.40+/-0.06 (rats); 0.45+/-0.10 (rabbits)]. At the same time, most epithelial cells shrank markedly while the intercellular spaces were wide open (electron microscopy studies). In freeze-fracture studies multi-strand tight-junction structures (only slightly modified by serosal hypertonicity in rabbits) were observed in control conditions. No structural changes were observed after mucosal hypertonicity (both in rats and rabbits). Immunohistochemical studies showed the expression of aquaporin 3 (AQP3) at the basolateral membrane of epithelial cells in the rat. A first conclusion is that the epithelium of the mammalian rectum is a highly polarized, aquaporin-3-containing, water permeability structure. The Jw increase induced by serosal hypertonicity was sensitive to mercurial agents in both species and no changes in unidirectional [14C]mannitol fluxes (Ps) or transepithelial resistance (RT) were observed during this Jw increase. These observations suggest a transcellular route for the osmotically induced increase in water fluxes. In the rabbit rectum the initial Jw response, associated with serosal hypertonicity, was a transient one. It was followed by a second, slow and HgCl2-sensitive Jw increase (a transient peak in paracellular mannitol permeability was also observed). A second conclusion is that serosal hypertonicity induces an increase in transcellular water permeability in both rat and rabbit rectum.
Assuntos
Soluções Hipertônicas , Permeabilidade , Reto/metabolismo , Reto/ultraestrutura , Água/metabolismo , Animais , Aquaporina 3 , Aquaporinas/análise , Tamanho Celular , Impedância Elétrica , Epitélio/química , Epitélio/metabolismo , Epitélio/ultraestrutura , Técnica de Fratura por Congelamento , Imuno-Histoquímica , Masculino , Manitol/metabolismo , Cloreto de Mercúrio/farmacologia , Microscopia Eletrônica , Concentração Osmolar , Coelhos , Ratos , Junções Íntimas/ultraestruturaRESUMO
Caco-2 cells, originated in a human colonic cancer, are currently used as model systems to study transepithelial transports. To further characterize their water permeability properties, clone P1 Caco-2 cells were cultured on permeable supports. At confluence, the transepithelial net water movement (Jw), mannitol permeability (Ps), and electrical resistance (R) were simultaneously measured. The observed results were correlated with transmission and freeze-fracture electron microscopy studies and compared with those obtained, in similar experimental conditions, in a typical mammalian epithelial barrier: the rabbit rectum. When the serosal solution was made hypertonic (50 mM polyethylene glycol-PEG), the spontaneously observed secretory Jw rapidly reversed, became absorptive and then stabilized. Simultaneously, the R values dropped and Ps went up. In the case of the rabbit rectal epithelium, a similar treatment did not elicit significant changes in the water permeability during the first 20 min following the osmotic challenge while there was a significant increase in the transepithelial resistance. After exposure to serosal hypertonicity, several morphological modifications developed in the Caco-2 cells: Localized dilations in the intercellular spaces and vacuoles in the cytoplasm appeared. Nevertheless, most cells remained in contact and no evidence of cell shrinking was observed. Simultaneously, the tight-junction structure was more or less disorganized. The filament network lost its sharpness and "omega" figures appeared, bordering the intercellular spaces. In some cases the tight-junction network was completely disrupted. In the case of the rabbit rectum the structural modifications were completely different: Serosal hypertonicity rapidly induced cell shrinking and the opening of the intercellular spaces, with no noticeable change in the tight-junction structure.(ABSTRACT TRUNCATED AT 250 WORDS)