RESUMEN
The stress of low oxygen concentrations in a waterlogged environment is minimized in some plants that produce aerenchyma, a tissue characterized by prominent intercellular spaces. It is produced by the predictable collapse of root cortex cells, indicating a programmed cell death (PCD) and facilitates gas diffusion between root and the aerial environment. The objective of this study was to characterize the cellular changes take place during aerenchyma formation in root of rice that accompany PCD. Scanning electron microscopy and transmission electron microscopy were used for cellular analysis of roots. Aerenchyma development was observed in both aerobic and flooded conditions. Structural changes in membranes and organelles were examined during development of root cortex cells to compare with previous examples of PCD. There was an initial collapse which started at a specific position in the mid cortex, indicating loss of turgor, and the cytoplasm became more electron dense. These cells were distinct in shape from those located towards the periphery. Mitochondria and endoplasmic reticulum appeared normal at this early stage though the tonoplast lost its integrity. Subsequently it underwent further degeneration while the plasmalemma retracted from the cell wall followed by death of neighboring cells followed a radial path. However, pycnosis of the nucleus, blebbing of plasma membrane and production of apoptotic bodies were not found which in turn indicated nonapoptotic PCD during aerenchyma formation in rice.
RESUMEN
BACKGROUND: Quality of Life (QOL) is an important health outcome measure in oncology. Given the underlying pressure of individual geo-political entities, a universal solution may not be applicable and hence there is a need to develop a regional tool and standardize the same to address the linguistic and socio-cultural factors. OBJECTIVE: To standardize a tool to assess the QOL of patients with cancer to suit the Indian scenario. MATERIALS AND METHODS: The samples were collected from the Cancer Institute (WIA), Chennai. Samples comprise of 400 patients with all sites and stages of cancer. PERIOD: January 2001 to January 2002. Patients were in the age range of 41-60 years. Thirty-eight items were pooled from existing tools, reviews, and the field trial, by which face and factorial validity were established. Reliability of the tool was also tested. Correlation analysis was done to find out the relation between the domains of QOL. STATISTICS USED: Principal component method with varimax rotation was used. Spearmen product moment correlation and Cronbach alpha coefficient were used for reliability analysis. RESULTS: Ten factors emerged with Eigen values ranging from 8.55 to 1.10 and accounted for 62.6% of variance. The first factor contributed maximally, 22% of variance. The remaining nine factors contributed totally to 40% of the variance on QOL. The ten factors that emerged were psychological well being, self-adequacy, physical well being, confidence in self-ability, external support, pain, mobility, optimism and belief, interpersonal relationship and self-sufficiency and independence. The internal consistency using Cronbach alpha test was 0.90 and split-half reliability was 0.74. CONCLUSION: The tool was found to be highly reliable and valid. It was feasible to administer it at clinical settings.