Tight binding of proteins to membranes from older human cells

The lens is an ideal model system for the study of macromolecular aging and its consequences for cellular function, since there is no turnover of lens fibre cells. To examine biochemical processes that take place in the lens and that may also occur in other long-lived cells, membranes were isolated from defined regions of human lenses that are synthesised at different times during life, and assayed for the presence of tightly bound cytosolic proteins using quantitative iTRAQ proteomics technology. A majority of lens beta crystallins and all gamma crystallins became increasingly membrane bound with age, however, the chaperone proteins alpha A and alpha B crystallin, as well as the thermally-stable protein, βB2 crystallin, did not. Other proteins such as brain-associated signal protein 1 and paralemmin 1 became less tightly bound in the older regions of the lens. It is evident that protein–membrane interactions change significantly with age. Selected proteins that were formerly cytosolic become increasingly tightly bound to cell membranes with age and are not removed even by treatment with 7 M urea. It is likely that such processes reflect polypeptide denaturation over time and the untoward binding of proteins to membranes may alter membrane properties and contribute to impairment of communication between older cells

Emergence and preservation of a chronically sick building

STUDY OBJECTIVE—To investigate the merits of case studies as complementary methodological approaches in the study of the sick building syndrome.
SETTING AND PARTICIPANTS—A Swedish office building with longstanding health problems, and its inhabitants.
DESIGN—This paper is a case study based both on historical and present, quantitative as well as qualitative, documentary material, produced over the years by distinct parties, and on semi-structured interviews.
RESULTS—Long drawn conflictive processes within the building were identified. It was revealed that the organisation for dealing with environmental problems was split, and ineffective with poor patterns of communication. It was suggested that this generated a situation of chronic stress leading to the persistence of symptoms.
CONCLUSIONS—By their capacity to identify internal processes within building contexts, case study methodology can contribute to a better understanding and management of sick building syndrome. The results of this study suggest that psychosocial factors, among them organisational structures and communication patterns, should be given close attention.


Keywords: case study; sick building syndrom