Could changes in the wheelchair delivery system improve safety?

Despite emerging evidence about the high incidence and severity of wheelchair-related injuries, regulations governing wheelchair safety are almost nonexistent in Canada. The authors believe that, to improve wheelchair safety, a concerted effort by government, manufacturers, purchasing groups, users and clinicians is needed. Health Canada''s Health Protection Branch should treat wheelchairs as medical devices (as defined in the Food and Drugs Act 1985) and improve its injury-reporting network. Manufacturers should give a higher priority to safety in wheelchair design, improve their educational materials and formalize postmarketing surveillance. Purchasing groups should try to ensure that they do not stifle innovation in wheelchair design by setting unrealistic reimbursement ceilings and should use their market power more effectively. Users should obtain their wheelchairs in specialized settings, heed safety warnings and make more effective use of litigation when such action is warranted. Clinicians should ensure that patients are equipped with the most appropriate wheelchair for their needs, that they are given adequate training in safe wheelchair use and that they understand the dangers involved. Rapid changes in wheelchair technology and emerging evidence about the high incidence and severity of injuries related to wheelchair use suggest that such changes are needed in the wheelchair delivery system.     

Endothelial cell junctions

In the course of a freeze-cleave study on intercellular junctions in the regenerating rat liver, we observed an unusual array of intramembranous particles located in regions of contact between endothelial cells lining the hepatic sinusoids. These arrays were characterized by an accumulation of particles which resembled a zonula occludens in their linear deployment but differed in that the contact regions were composed of individual particles which remained separated from each other by regular particle-free intervals.     

Protein kinases of the thylakoid membrane

The claim of Racker and co-workers (Lin, Z. F., Lucero, H. A., and Racker, E. (1982) J. Biol. Chem. 257, 12153-12156 and Lucero, H. A., Lin, Z. F., and Racker, E. (1982) J. Biol. Chem. 257, 12157-12160) that two protein kinases, designated CPK1 (25 kDa) and CPK2 (38 kDa), are present in spinach thylakoid membranes was investigated in light of results from this laboratory (Coughlan, S. J., and Hind, G. (1986) J. Biol. Chem. 261, 11378-11385) showing that 75-80% of the measurable protein kinase activity of isolated thylakoids is attributable to a protein kinase of 64 kDa apparent molecular mass. Extraction of thylakoid membranes with octyl glucoside/cholate according to the procedure of Lin et al. (Lin, Z. F., Lucero, H. A., and Racker, E. (1982) J. Biol. Chem. 257, 12153-12156) released proteins assignable to CPK1 and CPK2 on the basis of photoaffinity labeling with 8-azido-[32P]ATP. The 64-kDa protein kinase was present in this extract and accounted for greater than 80% of the total phosphotransferase activity toward lysine-rich histone as substrate; it was not labeled by the photoaffinity reagent. The three presumptive kinases were purified by ammonium sulfate precipitation, sucrose density gradient centrifugation, hydroxylapatite chromatography, and affinity chromatography. CPK1 was specifically eluted from Cibacron blue-Sepharose by 10 mM ATP; it electrophoresed on denaturing polyacrylamide gels as a single band with apparent molecular mass of 25 kDa. Its specific activity toward lysine-rich histone as substrate was approximately 250 pmol of phosphate transferred (mg protein)-1 min-1. The 64-kDa protein kinase was eluted from the affinity column by 1% (w/v) lithium dodecyl sulfate or from a histone IIIs-Sepharose affinity column by 0.25 M NaCl. Its specific activity towards lysine-rich histone was 100-200 times greater than that of CPK1. CPK2 eluted from the Cibacron blue affinity column in 10 mM NADP+; it had an apparent molecular mass of 38 kDa, possessed NADPH-dependent diaphorase activity (specific activity: 225 nmol of ferricyanide reduced (mg protein)-1 min-1), and cross-reacted with immunoglobulin raised against purified ferredoxin:NADP+ oxidoreductase, with which it was thus identified. Kinase activity was not detectable in CPK2 or in reductase isolated by conventional procedures.     

Hydrolysis of beet pulp polysaccharides by extracts of solid-state cultures of Pencicillium capsulatum

Extracts of solid-state cultures of Penicillium capsulatum grown on beet pulp exhibit cellulolytic, hemicellulolytic, and pectinolytic activities. Such extracts catalyzed extensive solubilization of untreated beet pulp. The effects of pH, temperature, and endproducts on the saccharification process were investigated.     

When Did I Begin? Conception of the Human Individual in History,Philosophy and Science by Norman M. Ford,Cambridge & New York,Cambridge University Press.

Coughlan reviews Norman M. Ford's When Did I Begin? Conception of the Human Individual in History, Philosophy and Science (Cambridge University Press; 1988). Ford, master of a Catholic theological college, has written a critique of the view that the life of the human person begins at the fertilization of the ovum. He believes that "when does a human being begin?" is an ontological question, and that attainment of personhood is a fact which calls for appropriate moral and legal attitudes, rather than a product of moral or legal attitudes or conventions. Ford bases his arguments on a detailed analysis of both the biological facts and the significance of early human embryology. Coughlan, while taking issue with some of Ford's reasoning, praises the book for its spirit of honesty, its well-argued transitions, and its instructiveness in human embryology. Ford's response to Coughlan follows the review.