Performance of Polymerase Chain Reaction Techniques Detecting Perforin in the Diagnosis of Acute Renal Rejection: A Meta-Analysis

BACKGROUND: Studies in the past have shown that perforin expression is up-regulated during acute renal rejection, which provided hopes for a non-invasive and reliable diagnostic method to identify acute rejection. However, a systematic assessment of the value of perforin as a diagnostic marker of acute renal rejection has not been performed. We conducted this meta-analysis to document the diagnostic performance of perforin mRNA detection and to identify potential variables that may affect the performance. METHODOLOGY/PRINCIPAL FINDINGS: Relevant materials that reported the diagnostic performance of perforin mRNA detection in acute renal rejection patients were extracted from electronic databases. After careful evaluation of the studies included in this analysis, the numbers of true positive, true negative, false positive and false negative cases of acute renal rejection identified by perforin mRNA detection were gathered from each data set. The publication year, sample origin, mRNA quantification method and housekeeping gene were also extracted as potential confounding variables. Fourteen studies with a total of 501 renal transplant subjects were included in this meta-analysis. The overall performance of perforin mRNA detection was: pooled sensitivity, 0.83 (95% confidence interval: 0.78 to 0.88); pooled specificity, 0.86 (95% confidence interval: 0.82 to 0.90); diagnostic odds ratio, 28.79 (95% confidence interval: 16.26 to 50.97); and area under the summary receiver operating characteristic curves value, 0.9107±0.0174. The univariate analysis of potential variables showed some changes in the diagnostic performance, but none of the differences reached statistical significance. CONCLUSIONS/SIGNIFICANCE: Despite inter-study variability, the test performance of perforin mRNA detected by polymerase chain reaction was consistent under circumstances of methodological changes and demonstrated both sensitivity and specificity in detecting acute renal rejection. These results suggest a great diagnostic potential for perforin mRNA detection as a reliable marker of acute rejection in renal allograft recipients

Cost or benefit for growth and flowering of seedlings and juvenile grassland plants in a dung environment

Endozoochory is a potential dispersal mode for numerous plant species. Although germination following endozoochory is well-documented, less is known about the costs and benefits associated with this dispersal mode in later life stages of established plants. The chemical and physical nature of dung differs between herbivores and might have specific effects on seedling establishment, growth and flowering. We conducted a growth experiment using 12 temperate grassland species with a known potential for endozoochory. We studied the effects of cattle and horse dung on the juvenile, growth and reproductive phase. Being a ruminant and a hindgut fermenter, respectively, cattle and horses are two physiologically contrasting herbivore species, producing structurally quite different dung types. They are additionally interesting model species as both are frequently introduced in temperate Europe grassland management. Seedling biomass and growth rate, height, ramification, flowering and biomass of grown plants were measured in an attempt to quantify the benefits of endozoochorously dispersed seeds compared to seeds dispersed by other means and thus growing in a virtually dung-free environment. Few species were affected by the presence of dung in the juvenile phase while most species generally benefitted from being deposited in dung in later life stages. Positive responses of Agrostis capillaris, Agrostis stolonifera, Alopecurus myosuroides, Helianthemum nummularium, Poa annua, Trifolium repens and Trifolium pratense were found, while dung had a negative effect on Juncus bufonius. The initial losses of viable seeds through the digestive system of herbivores might, therefore, be partially compensated by enhanced growth and flowering in some species