Platelets in Early Antibody-Mediated Rejection of Renal Transplants

Antibody-mediated rejection is a major complication in renal transplantation. The pathologic manifestations of acute antibody-mediated rejection that has progressed to functional impairment of a renal transplant have been defined in clinical biopsy specimens. However, the initial stages of the process are difficult to resolve with the unavoidable variables of clinical studies. We devised a model of renal transplantation to elucidate the initial stages of humoral rejection. Kidneys were orthotopically allografted to immunodeficient mice. After perioperative inflammation subsided, donor-specific alloantibodies were passively transferred to the recipient. Within 1 hour after a single transfer of antibodies, C4d was deposited diffusely on capillaries, and von Willebrand factor released from endothelial cells coated intravascular platelet aggregates. Platelet-transported inflammatory mediators platelet factor 4 and serotonin accumulated in the graft at 100- to 1000-fold higher concentrations compared with other platelet-transported chemokines. Activated platelets that expressed P-selectin attached to vascular endothelium and macrophages. These intragraft inflammatory changes were accompanied by evidence of acute endothelial injury. Repeated transfers of alloantibodies over 1 week sustained high levels of platelet factor 4 and serotonin. Platelet depletion decreased platelet mediators and altered the accumulation of macrophages. These data indicate that platelets augment early inflammation in response to donor-specific antibodies and that platelet-derived mediators may be markers of evolving alloantibody responses.     

新化合物 A-失碳-17β-羟基-17α-乙炔基-Δ3(5),9(10)-雌甾二烯-2-酮的合成

报道新化合物A-失碳-17β-羟基-17α-乙炔基-Δ^3(5),9(10)-雌甾二烯-2-酮2的合成。文中探讨了用炔钾粗品对A-失碳-Δ^3(5),9(10)-雌甾二烯-2，17-二酮１和Ａ-失碳-６β，１９-环氧-Δ³-雄甾-2，17-二酮3的选择性炔化，分别得标题化合物2（44%）及Ａ-失碳-17β-羟基-17α-乙炔基-６β，１９-环氧-Δ³雄甾-2-酮４（６５％），４经还原性破开环氧、去羟甲基和去醋酰氧基合成了标题化合物２。四步总收率为３４％。     

Ureteral calculi: percutaneous removal using modified basket extractors and fluoroscopy

Two modified helical basket extractors are described that have increased the success rate of removing ureteral calculi using fluoroscopy from 63% to 92%. Initially a rather stiff and expandable basket with a 20-cm filiform tip is used with coaxial catheters and sheath (stage 1). If this procedure is unsuccessful, a basket with two long cable ends is passed from the nephrostomy out through the urethra (stage 2). When used with coaxial bladder catheters, this technique allows dilatation of the vesicoureteric junction and retrograde catheterization and injection of fluids or gas to dislodge the stone prior to extraction. In a series of 38 patients, stones were removed in all but three (a success rate of 92%). In five cases small stones (less than 5 mm) were not retrieved but subsequent studies were normal. Ureteral stones were found in the abdominal ureter in 28 cases, in the pelvic ureter in seven cases, and in multiple sites in three cases. Stones were larger than 1 cm in 27.7% of cases. Postextraction mucosal edema with reduced ureteral patency was common but usually cleared in 2-3 days. Occasional complications were related to the nephrostomy.     

Reframing climate change as a public health issue: an exploratory study of public reactions

Background  

Climate change is taking a toll on human health, and some leaders in the public health community have urged their colleagues to give voice to its health implications. Previous research has shown that Americans are only dimly aware of the health implications of climate change, yet the literature on issue framing suggests that providing a novel frame - such as human health - may be potentially useful in enhancing public engagement. We conducted an exploratory study in the United States of people's reactions to a public health-framed short essay on climate change.     

Beyond C4d: Other Complement-Related Diagnostic Approaches to Antibody-Mediated Rejection

Complement is a multifunctional system of receptors and regulators as well as effector molecules. Both the pathogenic and diagnostic power of complement is based on the capacity of the complement system to amplify innate and adaptive immunity. This amplification is accomplished through two strategies: (1) enzymatic reactions in the complement cascade, and (2) stimulation of leukocytes, platelets and parenchymal cells through specific receptors or receptor-independent pore formation. The mechanisms by which complement mediates and modifies nonspecific inflammation, antibody-mediated injury and T-cell responses are of particular significance to the pathogenesis of transplant rejection. Understanding the mechanisms by which complement integrates the interactions of leukocytes, platelets and parenchymal cells offers opportunities to further refine the diagnosis of rejection.     

The influence of stimulus size on measured visual field extent in infants.

PURPOSE: To compare measured visual field extent for a 6 degrees stimulus (typical size used in studies of infants) with a 1.5 degrees stimulus (similar to the largest size used in Goldmann perimetry) in young infants. METHODS: A total of 120 infants (60 each at 3.5 months and 7 months of age) and 24 adults were tested monocularly with a kinetic perimetry procedure using a black double-arc perimeter. Each subject was tested with either a 6 degrees or 1.5 degrees white sphere, which was mounted on a black wand and moved smoothly toward the intersection of the perimeter arms at 3.4 degrees /s. Visual field extent along each perimeter arm was defined as the median of 2 to 3 measurements of the position of the leading edge of the stimulus when the subject made an eye movement toward the stimulus. RESULTS: The 6 degrees stimulus produced larger measured visual field extent than the 1.5 degrees stimulus in 3.5-month olds (temporal field only) and in 7-month olds (nasal and temporal field), but not in adults. CONCLUSIONS: Using the testing conditions of the present study, increasing stimulus size beyond the largest used in a Goldmann perimeter (approximately 2 degrees) increases measured visual field extent in young infants, but not in adults. This may relate to differences in peripheral summation areas or to differences in attentional factors between infants and adults.