Useful Surrogate (useful + surrogate)

Distribution by Scientific Domains


Selected Abstracts


Population trends of widespread woodland birds in Europe

IBIS, Issue 2007
RICHARD D. GREGORY
We explore population trends of widespread and common woodland birds using data from an extensive European network of ornithologists for the period 1980,2003. We show considerable differences exist in the European trends of species according to the broad habitat they occupy and the degree to which they specialize in habitat use. On average, common forest birds are in shallow decline at a European scale; common forest birds declined by 13%, and common forest specialists by 18%, from 1980 to 2003. In comparison, populations of common specialists of farmland have declined moderately, falling on average by 28% from 1980 to 2003. These patterns contrast with that shown by generalist species whose populations have been roughly stable over the same period, their overall index increasing by 3%. There was some evidence of regional variation in the population trends of these common forest species. The most obvious pattern was the greater stability of population trends in Eastern Europe compared with other regions considered. Among common forest birds, long-distance migrants and residents have on average declined most strongly, whereas short-distance migrants have been largely stable, or have increased. There was some evidence to suggest that ground- or low-nesting species have declined more strongly on average, as have forest birds with invertebrate diets. Formal analysis of the species trends confirmed the influence of habitat use, habitat specialization and nest-site; the effects of region and migration strategy were less clear-cut. There was also evidence to show that year-to-year variation in individual species trends at a European scale was influenced by cold winter weather in a small number of species. We recommend that the species trend information provided by the new pan-European scheme should be used alongside existing mechanisms to review the conservation status of European birds. The analysis also allows us to reappraise the role of common forest bird populations as a potential barometer of wider forest health. The new indicator appears to be a useful indicator of the state of widespread European forest birds and might prove to be a useful surrogate for trends in forest biodiversity and forest health, but more work is likely to be needed to understand the interaction between bird populations and their drivers in forest. [source]


Original Article: Clinical Investigation: Anterior perirectal fat tissue thickness is a strong predictor of recurrence after high-intensity focused ultrasound for prostate cancer

INTERNATIONAL JOURNAL OF UROLOGY, Issue 9 2010
Makoto Sumitomo
Objective: To evaluate if and why obesity affects the clinical outcome in patients undergoing high-intensity focused ultrasound (HIFU) treatment for prostate cancer (CaP). Methods: 115 patients who underwent HIFU treatment for localized CaP were categorized as obese, overweight or normal according to body mass index (BMI). The thickness of the anterior perirectal fat tissue (APFT) was measured by transrectal ultrasonography. Treatment was considered to have failed in the case of biochemical failure according to the Phoenix definition, positive follow-up biopsy or initiation of salvage therapy. Cox proportional hazards analyses were used to identify possible predictors for disease free survival (DFS), and an experimental fat tissue model was made to evaluate the ablation effect at the target tissue. Results: According to the classification by the Western Pacific Regional Office of WHO, 43 patients were of normal weight, 24 were overweight and 48 were obese. The BMI groups did not differ in Gleason score, prostate-specific antigen level at diagnosis or clinical stage. There were, however, significant correlations between BMI and prostate-specific antigen nadir (P < 0.001), and BMI and APFT thickness (P < 0.01). Multivariate analyses showed that BMI fails to be an independent predictor of DFS when APFT (P < 0.0001) is included as a variable. Conclusions: Our results suggest that APFT thickness, for which obesity could be a useful surrogate, might represent the causative factor for poor clinical outcome after transrectal HIFU treatment for CaP. [source]


The Effect of Rosuvastatin on Insulin Sensitivity and Pancreatic Beta-Cell Function in Nondiabetic Renal Transplant Recipients

AMERICAN JOURNAL OF TRANSPLANTATION, Issue 6 2009
A. Sharif
Interventions to attenuate abnormal glycemia posttransplantation are required. In addition, surrogate markers of declining glycemic control are valuable. Statins may have pleiotropic properties that attenuate abnormal glucose metabolism. We hypothesized statins would improve glucose metabolism and HbA1c would be advantageous as a surrogate for worsening glycemia. We conducted a prospective, randomized, placebo controlled, crossover study in 20 nondiabetic renal transplant recipients at low risk for NODAT and compared effects of rosuvastatin on insulin secretion/sensitivity. Mathematical model analysis of an intravenous glucose tolerance test determined first-phase insulin secretion, insulin sensitivity and disposition index. Second-phase insulin secretion was determined with a meal tolerance test. Biochemical/clinical parameters were also assessed. Rosuvastatin significantly improved total cholesterol (,30%, p < 0.001), LDL cholesterol (,44%, p < 0.001) and triglycerides (,19%, p = 0.013). C-reactive protein decreased but failed to achieve statistical significance (,31%, p = 0.097). Rosuvastatin failed to influence any glycemic physiological parameter, although an inadequate timeframe to allow pleiotropic mechanisms to clinically manifest raises the possibility of a type II statistical error. On multivariate analysis, glycated hemoglobin (HbA1c) correlated with disposition index (R2= 0.201, p = 0.006), first-phase insulin secretion (R2= 0.106, p = 0.049) and insulin sensitivity (R2= 0.136, p = 0.029). Rosuvastatin fails to modify glucose metabolism in low-risk patients posttransplantation but HbA1c is a useful surrogate for declining glycemic control. [source]


Medullary pain facilitating neurons mediate allodynia in headache-related pain,

ANNALS OF NEUROLOGY, Issue 2 2009
Rebecca M. Edelmayer BS
Objective To develop and validate a model of cutaneous allodynia triggered by dural inflammation for pain associated with headaches. To explore neural mechanisms underlying cephalic and extracephalic allodynia. Methods Inflammatory mediators (IM) were applied to the dura of unanesthetized rats via previously implanted cannulas, and sensory thresholds of the face and hind-paws were characterized. Results IM elicited robust facial and hind-paw allodynia, which peaked within 3 hours. These effects were reminiscent of cutaneous allodynia seen in patients with migraine or other primary headache conditions, and were reversed by agents used clinically in the treatment of migraine, including sumatriptan, naproxen, and a calcitonin gene,related peptide antagonist. Consistent with clinical observations, the allodynia was unaffected by a neurokinin-1 antagonist. Having established facial and hind-paw allodynia as a useful animal surrogate of headache-associated allodynia, we next showed that blocking pain-facilitating processes in the rostral ventromedial medulla (RVM) interfered with its expression. Bupivacaine, destruction of putative pain-facilitating neurons, or block of cholecystokinin receptors prevented or significantly attenuated IM-induced allodynia. Electrophysiological studies confirmed activation of pain-facilitating RVM "on" cells and transient suppression of RVM "off" cells after IM. Interpretation Facial and hind-paw allodynia associated with dural stimulation is a useful surrogate of pain associated with primary headache including migraine and may be exploited mechanistically for development of novel therapeutic strategies for headache pain. The data also demonstrate the requirement for activation of descending facilitation from the RVM for the expression of cranial and extracranial cutaneous allodynia, and are consistent with a brainstem generator of allodynia associated with headache disorders. Ann Neurol 2009;65:184,193 [source]


Evidence that Branch Cuvettes are Reasonable Surrogates for Estimating O3 Effects in Entire Tree Crowns

PLANT BIOLOGY, Issue 2 2007
C. Then&
Abstract: Within the scope of quantifying ozone (O3) effects on forest tree crowns it is still an open question whether cuvette branches of adult trees are reasonable surrogates for O3 responses of entire tree crowns and whether twigs exhibit autonomy in defense metabolism in addition to carbon autonomy. Therefore, cuvette-enclosed branches of mature beech (Fagus sylvatica) trees were compared with branches exposed to the same and different ozone regimes by a free-air fumigation system under natural stand conditions by means of a vice versa experiment. For this purpose, cuvettes receiving 1 O3 air were mounted in trees exposed to 2 O3 and cuvettes receiving 2 O3 air were mounted in trees exposed to 1 O3 in the upper sun crown. At the end of the fumigation period in September 2004, leaves were examined for differences in gas exchange parameters, pigments, antioxidants, carbohydrates, and stable isotope ratios. No significant differences in foliar gas exchange, total carbohydrates, stable isotope ratios, pigment, and antioxidant contents were found as a consequence of cuvette enclosure (cuvette versus free-air branches) of the same O3 concentrations besides increase of glucose inside the cuvettes and reduction of the de-epoxidation state of the xanthophyll cycle pigments. No significant ozone effect was found for the investigated gas exchange and most biochemical parameters. The total and oxidized glutathione level of the leaves was increased by the 2 O3 treatment in the cuvette and the free-air branches, but this effect was significant only for the free-air branches. From these results we conclude that cuvette branches are useful surrogates for examining the response of entire tree crowns to elevated O3 and that the defence metabolism of twigs seems to be at least partially autonomous. [source]