Distinct roles for laminin globular domains in laminin α1 chain mediated rescue of murine laminin α2 chain deficiency

Background: Laminin a2 chain mutations cause congenital muscular dystrophy with dysmyelination neuropathy (MDC1A). Previously, we demonstrated that laminin a1 chain ameliorates the disease in mice. Dystroglycan and integrins are major laminin receptors. Unlike laminin a2 chain, a1 chain binds the receptors by separate domains; laminin globular (LG) domains 4 and LG1-3, respectively. Thus, the laminin a1 chain is an excellent tool to distinguish between the roles of dystroglycan and integrins in the neuromuscular system. Methodology/Principal Findings: Here, we provide insights into the functions of laminin a1LG domains and the division of their roles in MDC1A pathogenesis and rescue. Overexpression of laminin a1 chain that lacks the dystroglycan binding LG4-5 domains in a2 chain deficient mice resulted in prolonged lifespan and improved health. Importantly, diaphragm and heart muscles were corrected, whereas limb muscles were dystrophic, indicating that different muscles have different requirements for LG4-5 domains. Furthermore, the regenerative capacity of the skeletal muscle did not depend on laminin a1LG4-5. However, this domain was crucial for preventing apoptosis in limb muscles, essential for myelination in peripheral nerve and important for basement membrane assembly. Conclusions/Significance: These results show that laminin a1LG domains and consequently their receptors have disparate functions in the neuromuscular system. Understanding these interactions could contribute to design and optimization o

Nurses´ experiences of strain and their reactions in the care of severely demented patients.

All nurses (N = 132) on the wards specializing in the care of the demented within a municipality were given two scales to assess their view of common patient actions and how easy they thought those actions were to deal with in the care situation, and to assess their emotional reactions during the provision of care. Also the Maslach burnout Inventory (MBI) and the Work Related Strain Inventory (WRSI) were used to test concurrent validity. Based on principal component analysis, the nurses' view of patient actions resulted in being agitated, unruly, living empty lives, being peaceful, dependent, non-responsive and cooperative, and the nurses' view of difficulties in dealing with patient actions revealed ability to manage deprivation, agitation, desertedness, wilfulness, peacefulness and cooperation. A three-factor solution was chosen for the emotional reactions: feelings of devotion - rejection, association - dissociation and usefulness - uselessness. Agitated and dependent patient actions were found to be most common while agitation and desertedness were regarded as most difficult. Patient seen as agitated and living empty lives related to the provision of care being difficult while dependence related to care as being easy to provide. Thus the findings gave further support to the belief that viewing the patient's life as meaningful as well as being able to develop a cooperative nurse-patient relationship is crucial for nurses' experience of strain. Thus support should be directed towards achieving this kind of relationship

Purification and identification of the violaxanthin de-epoxidase as a 43 kDa protein

Violaxanthin deepoxidase (VDE) has been purified from spinach (Spinacia oleracea) leaves. The purification included differential sonication of thylakoid membranes, differential (NH4)2SO4 fractionation, gel filtration chromatography and finally either hydrophobic interaction chromatography or anion exchange chromatography. A total purification of more than 5000-fold compared to the original thylakoids enabled the identification of a 43 kDa protein as the VDE, in contrast to earlier reported molecular weight of 54–60 kDa. A detailed comparison was made for the VDE activity and polypeptide pattern for the different fractions throughout the purification and the best correlation was always found for the 43 kDa protein. The highest specific activity obtained was 256 mol g–1 s–1 protein, which is at least 10-fold higher than reported earlier. We estimate that there is 1 VDE molecule per 20–100 electron transport chains. The 43 kDa protein was N-terminally sequenced, after protection of cysteine residues with -mercaptoethanol and iodoacetamid, and a unique sequence of 20 amino acids was obtained. The amino acid composition of the protein revealed a high abundance of charged and polar amino acids and remarkably, 11 cysteine residues. Two other proteins (39.5 kDa and 40 kDa) copurifying with VDE were also N-terminally sequenced. The N-terminal part of the 39.5 kDa protein showed complete sequence identity both with the N-terminal part of cyt b 6 and an internal sequence of polyphenol oxidase