The College of American Pathologists, 1946-1996. Quality Assurance Service

Since its creation in 1970, the College of American Pathologists Quality Assurance Service Committee has provided important and highly respected interlaboratory programs for daily quality control. In 1988, this committee extended its domain by announcing Q-Probes, a unique benchmarking program for laboratory quality assurance. Because of the success and rapid growth of this program during the next 2 years, the Quality Assurance Service Committee expanded into two committees, namely, QAS-QC and QAS-QA, with expertise concentrated, respectively, in quality control and quality assurance. These committees have compiled a history of significant scientific and educational contributions to members, the international laboratory community, other physicians, and patients. New directions for both committees are now underway so that their contributions can continue in the rapidly changing field of pathology and laboratory medicine.     

The KDEL receptor, ERD2, regulates intracellular traffic by recruiting a GTPase-activating protein for ARF1

The small GTPase ADP-ribosylation factor 1 (ARF1) is a key regulator of intracellular membrane traffic. Regulators of ARF1, its GTPase-activating protein (GAP) and its guanine nucleotide exchange factor have been identified recently. However, it remains uncertain whether these regulators drive the GTPase cycle of ARF1 autonomously or whether their activities can be regulated by other proteins. Here, we demonstrate that the intracellular KDEL receptor, ERD2, self-oligomerizes and interacts with ARF1 GAP, and thereby regulates the recruitment of cytosolic ARF1 GAP to membranes. Because ERD2 overexpression enhances the recruitment of GAP to membranes and results in a phenotype that reflects ARF1 inactivation, our findings suggest that ERD2 regulates ARF1 GAP, and thus regulates ARF1-mediated transport.     

Thrombolytic therapy in stroke. What do clinical tests prove?

Despite the increased risk of intracranial haemorrhage associated with the use of thrombolytic treatment of stroke. American studies have shown patients treated with rt-PA (recombinant plasminogen activator) within three hours of the onset of symptoms to manifest 30 per cent less disability at three-month follow-up than those placebo. However, until satisfactory criteria for the use of rt-PA are available, caution is essential, and thrombolytic therapy should be restricted to specialised centres. It is also important to promote public awareness of the stroke patient's need of immediate treatment at a specialised stroke unit.     

Rock mass characterization for underground hard rock mines

Rock mass characterization is an integral part of rock engineering practice. There are several classification systems used in underground mine design, however, most Canadian mines rely on only one of three classification systems. It is interesting to note that these systems—RQD, RMR and Q system—have their origins in civil engineering. This paper reviews the current state of these classification systems as employed in the mining industry. The first part focuses on the determination of the field parameters, with emphasis on the modifications to each parameter over the last 20 years. The difference between classification parameters that influence rock mass strength estimation and those that influence engineering design is emphasized. The second part of the paper focuses on the design recommendations based on these systems, such as maximum span, opening geometry, and support recommendations. The paper concludes with reference to errors that may arise in particular conditions.     

Biophysical processes and bioregional planning: The Niagara Escarpment of southern Ontario, Canada

The Niagara Escarpment is the dominant landscape feature of Southern Ontario and has been designated a UNESCO World Biosphere Reserve. As with many such natural features, the resource planning and management strategies developed tend to be based upon the present-day situation rather than upon a recognition of the changing and evolving nature of the feature. To develop strategies incorporating change demands that a knowledge be gained of the processes operating in those components of the ecosystems in which measurable activity will take place within a planning framework; that is a timescale of several decades. In this particular case, the context is natural resource planning for the scarp face itself. The critical system elements are those related to earth surface processes, forest ecosystem dynamics, and in particular, their interrelationships. Different planning objectives require information at differing spatial scales. Yet these objectives must be related, whether they are local site-specific issues, or are related to the maintenance of the biodiversity of the whole 725 km of the Escarpment. One way to achieve these goals is to establish a hierarchical system of spatially nested land units. These units, however, must be based on the underlying biophysical processes responsible for the dynamics in any one of these spatially determined frameworks. In this case, the underlying biophysical processes relating to geomorphology and forest ecosystem dynamics are found to be influenced by one of three dominant slope forms. The recurrence of these slope forms throughout the Escarpment then permits 9 distinct regional land units to be identified. Within these units, site-specific analysis examines earth surface/forest interactions and change. Subsequently, from these site specific analyses data are accumulated to develop a more general model of earth surface/forest ecosystem interaction for the Escarpment as a whole.