104,654 research outputs found
Contrast-enhanced ultrasonography of the canine adrenal gland: assessment of the feasability of this procedure
No full textRenal function and morphology in aged Beagle dogs before and after hydrocortisone administration
No full textObjectives of this study were to evaluate glomerular filtration rate (GFR), renal structural changes and proteinuria in aged Beagle dogs before and after administration of hydrocortisone. Eleven Beagle dogs ≥ 10 years were treated with either hydrocortisone (HC group, n=6) or a placebo (control group, n=5). Measurement of urinary markers, GFR and kidney biopsies were performed before (T0), during (T16wks) and after discontinuing HC administration (T24wks).
Results indicate that HC administration causes a significant increase in GFR. During HC treatment, proteinuria, urinary albumin-to-creatinine (c) ratio, immunoglobulin G/c and retinol-binding protein/c were higher compared to baseline in the HC group. At T0, rare to mild glomerular, tubular and interstitial lesions were detected in all HC dogs and rare to moderate changes in all control dogs. Glomerulosclerosis progressed in both groups, with most severe scores at T24wks. Tubular atrophy was detected in 3 HC dogs at T16wks and T24wks, but was also found in up to 5 control dogs throughout the study. At every time point, up to 5 HC dogs and all control dogs had rare to moderate interstitial inflammation. Rare to mild interstitial fibrosis was found in up to 3 HC dogs at T16wks and T24wks, and severe fibrosis in 1 HC dog at T24wks. Up to 4 control dogs had rare to mild fibrosis at all time points. These findings indicate that clinically healthy, aged Beagle dogs may have considerable renal lesions and proteinuria, which could have implications for experimental or toxicological studies. Additional research is needed to further elucidate glucocorticoid effects on renal structure, but functional changes such as hyperfiltration and proteinuria warrant attention to kidney function canine patients with Cushing's syndrome or receiving exogenous glucocorticoids
Contrast harmonic ultrasound appearance of consecutive percutaneous renal biopsies in dogs
No full textUltrasound-guided percutaneous renal biopsy may be associated with complications, especially when using larger needles. Contrast harmonic ultrasound increases blood pool echo intensity, enhancing parenchymal lesions. Therefore, contrast harmonic ultrasound is a potential alternative screening method for postbiopsy renal lesions. Renal biopsies were performed using 14G needles in 11 healthy Beagles, at three occasions: 0 ("Baseline Biopsy"; BB), 4 ("Biopsy 2"; B2), and 6 months ("Biopsy 3"; B3). Ultrasound and contrast harmonic ultrasound of biopsied kidneys were performed approximately 30min after biopsy (week 0) at BB and B2, and repeated once every week (weeks 1-3) until normal appearance. At B3, only contrast harmonic ultrasound was performed, both immediately and 30-min postbiopsy. Contrast harmonic ultrasound images were reviewed using subjective and semiquantitative methods to describe lesions including number, shape, size, sharpness, echogenicity, and evolution. More renal lesions were detected with contrast harmonic ultrasound (22/22) compared with conventional ultrasound (14/22). The majority appeared at week 0 as hypoechoic tract(s) (27/33), the other (6/33) as ill-defined areas or area/tract combination, all having variable size, shape, and echogenicity. Seven tracts had a small subcapsular hematoma. In most kidneys, similar or gradual decrease of size and sharpness, and increased echogenicity was observed until normal appearance occurred at week 1 (1/22), week 2 (18/22), or week 3 (22/22). Two Beagles developed complications. At B3, immediately postbiopsy, tracts were hyperechoic in 9/11 kidneys, becoming hypoechoic again 30min later. Contrast harmonic ultrasound is a valuable method to evaluate postbiopsy renal lesions in dogs. © 2011 Veterinary Radiology & Ultrasound
Use of quantitative contrast-enhanced ultrasonography to detect diffuse renal changes in Beagles with iatrogenic hypercortisolism
No full textObjective-To determine the feasibility of quantitative contrast-enhanced ultrasonography (CEUS) for detection of changes in renal blood flow in dogs before and after hydrocortisone administration. Animals-11 Beagles Procedure-Dogs were randomly assigned to 2 treatment groups: oral administration of hydrocortisone (9.6 mg/kg; n = 6) or a placebo (5; control group) twice a day for 4 months, after which the dose was tapered until treatment cessation at 6 months. Before treatment began and at 1, 4, and 6 months after, CEUS of the left kidney was performed by IV injection of ultrasonography microbubbles. Images were digitized, and time-intensity curves were generated from regions of interest in the renal cortex and medulla. Changes in blood flow were determined as measured via contrast agent (baseline [background] intensity, peak ntensity, area under the curve, arrival time of contrast agent, time-to-peak intensity, and speed of contrast agent transport). Results-Significant increases in peak intensity, compared with that in control dogs, were observed in the renal cortex and medulla of hydrocortisone-treated dogs 1 and 4 months after treatment began. Baseline intensity changed similarly. A significant increase from control values was also apparent in area under the curve for the renal cortex 4 months after hydrocortisone treatment began and in the renal medulla 1 and 4 months after treatment began. A significant time effect with typical time course was observed, corresponding with the period during which hydrocortisone was administered. No difference was evident in the other variables between treated and control dogs. Conclusions and Clinical Relevance-Quantitative CEUS allowed detection of differences in certain markers of renal blood flow between dogs treated orally with and without hydrocortisone. Additional studies are needed to investigate the usefulness of quantitative CEUS in the diagnosis of diffuse renal lesions
Contrast-enhanced ultrasonography of the normal canine adrenal gland
No full textContrast-enhanced ultrasonography is useful in differentiating adrenal gland adenomas from nonadenomatous
lesions in human patients. The purposes of this study were to evaluate the feasibility and to describe contrastenhanced
ultrasonography of the normal canine adrenal gland. Six healthy female Beagles were injected with an
intravenous bolus of a lipid-shelled contrast agent (SonoVue
s
). The aorta enhanced immediately followed by the
renal artery and then the adrenal gland. Adrenal gland enhancement was uniform, centrifugal, and rapid from
the medulla to the cortex. When maximum enhancement was reached, a gradual homogeneous decrease in
echogenicity of the adrenal gland began and simultaneously enhancement of the phrenicoabdominal vessels was
observed. While enhancement kept decreasing in the adrenal parenchyma, the renal vein, caudal vena cava, and
phrenicoabdominal vein were characterized by persistent enhancement until the end of the study. A second
contrast enhancement was observed, corresponding to the refilling time. Objective measurements were performed
storing the images for off-line image analysis using Image J (ImageJr). The shape of the time–intensity
curve reflecting adrenal perfusion was similar in all dogs. Ratios of the values of the cortex and the medulla to the
values of the renal artery were characterized by significant differences from initial upslope to the peak allowing
differentiation between the cortex and the medulla for both adrenal glands only in this time period. Contrastenhanced
ultrasonography of the adrenal glands is feasible in dogs and the optimal time for adrenal imaging is
between 5 and 90 s after injection
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Contrast-enhanced ultrasonography of the normal canine adrenal gland
No full textContrast-enhanced ultrasonography is useful in differentiating adrenal gland adenomas from nonadenomatous lesions in human patients. The purposes of this study were to evaluate the feasibility and to describe contrast-enhanced ultrasonography of the normal canine adrenal gland. Six healthy female Beagles were injected with an intravenous bolus of a lipid-shelled contrast agent (SonoVue®). The aorta enhanced immediately followed by the renal artery and then the adrenal gland. Adrenal gland enhancement was uniform, centrifugal, and rapid from the medulla to the cortex. When maximum enhancement was reached, a gradual homogeneous decrease in echogenicity of the adrenal gland began and simultaneously enhancement of the phrenicoabdominal vessels was observed. While enhancement kept decreasing in the adrenal parenchyma, the renal vein, caudal vena cava, and phrenicoabdominal vein were characterized by persistent enhancement until the end of the study. A second contrast enhancement was observed, corresponding to the refilling time. Objective measurements were performed storing the images for off-line image analysis using Image J (ImageJ©). The shape of the time-intensity curve reflecting adrenal perfusion was similar in all dogs. Ratios of the values of the cortex and the medulla to the values of the renal artery were characterized by significant differences from initial upslope to the peak allowing differentiation between the cortex and the medulla for both adrenal glands only in this time period. Contrast-enhanced ultrasonography of the adrenal glands is feasible in dogs and the optimal time for adrenal imaging is between 5 and 90s after injection. © 2011 Veterinary Radiology & Ultrasound
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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