The objective of this study was to evaluate quantitatively and qualitatively the effect of image subtraction on the image quality of three-dimensional (3D) gadolinium-enhanced MR angiograms of the renal arteries. Breath-hold 3D gadolinium MR angiography (MRA) as well as conventional contrast angiography of the renal arteries was performed on 20 patients with suspected renovascular hypertension. MR angiograms were acquired before and during dynamic infusion of gadolinium-diethylenetriamine pentaacetic acid (Gd-DTPA). Contrast-enhanced images were compared with images that had undergone voxel-by-voxel signal intensity subtraction of contrast-enhanced data from precontrast data. One false positive finding for significant renal artery stenosis was recorded with MRA using conventional angiography as the gold standard. Image subtraction did not alter the diagnosis at MRA in any case. The mean contrast-to-noise ratio (CNR) was significantly higher (P < .05) on the subtraction MR angiograms compared to the nonsubtracted MR angiograms. There was no significant difference in the signal-to-noise ratio (SNR). Qualitative analysis revealed a significant improvement in image quality after image subtraction with respect to visualization of the distal renal arteries. In conclusion, image subtraction improves the quality of renal MRA in terms of both CNR and visualization of the distal renal arteries.

Adult↗

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Hemodynamic interactions of hemodilution, anaesthesia, propranolol pretreatment and hypovolaemia. I. Systemic circulation.

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Animals↗

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Hemodynamic interactions of hemodilution, anaesthesia, propranolol pretreatment and hypovolaemia. II: Coronary circulation.

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Animals↗

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[Mannheim concept of preoperative autologous blood donation and perioperative autologous blood transfusion in hip endoprosthesis surgery].

PURPOSE: To investigate the efficiency of preoperative autologous deposit and intra- and postoperative cell salvage (CS) to reduce homologous transfusion in hip arthroplasty and revision hip arthroplasty. METHODS: In a retrospective study, the data of 1402 patients scheduled for hip arthroplasty and for revision hip arthroplasty were analysed. RESULTS: 767 women and 635 men, age 62.9 +/- 9.8 years (x +/- s) were included in the study. 1270 were scheduled for hip arthroplasty, 132 for revision hip arthroplasty. Of the autologous donors, 51 patients predeposited four units, 1020 patients three, 204 patients two, 39 patients one unit. 88 patients who had not enrolled in the autologous donation program but received CS served as a control group. Blood loss in autologous donors amounted to 1620 (220-5620) ml in hip arthroplasty and 2830 (950-7910) ml in revision arthroplasty. CS was employed in part of the cases in arthroplasty and in all revision operations. 470 (0-2200) ml and 705 (0-2200) were retransfused. In hip arthroplasty 227 of 1182 patients (19.2%) received homologous blood. Homologous transfusion in patients with coxarthrosis due to acetabular protrusio, avascular necrosis of the femoral head and hip dysplasia showed a trend to higher values. Patients who had donated 3 units and received CS required homologous transfusion in 12.4% of the cases. CS reduced the homolgous transfusion rate significantly if the preoperative hemoglobin concentration was < or = 12 g/dl. A group of autologous donors receiving CS was matched with patients receiving CS only. 12 of 76 (15.8%) vs. 45 of 76 (59.2%) required homologous transfusion. In revision hip arthroplasty 58 of 132 patients (43.9%) required homologous blood. CONCLUSIONS: Preoperative deposit reduces homologous transfusion requirements considerably in hip surgery. Under the conditions studied CS should be employed in hip arthroplasty in addition to preoperative deposit if the preoperative hemoglobin concentration falls below 12 g/dl. In revision arthroplasty, 4 or more autologous units should be predeposited and CS should be used regularly.

Aged↗

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Utero-ovarian interaction in the regulation of reproductive function.

The physiological regulation of fertile reproductive cycle in mammals depends on interactions between hypothalamus-pituitary, ovarian and uterine stimuli. Over the past 20 years, much has been learned about the interrelation between the affluent and effluent lymph and vascular drainage in and around both ovarian and uterine tissues. An essential feature in the regulation of the fertile cycle is the functional status of the ovary, particularly the corpus luteum. During the time of implantation and the early pregnancy, an active corpus luteum is essential. As human chorionic gonadotrophin (HCG) is important in the maintenance of the corpus luteum, we investigated if it was produced by the cyclic endometrium. Immunohistochemical and in-situ hybridization reactions were performed but neither identified the presence of HCG during the proliferative phase. Positive staining and beta-human chorionic gonadotrophin (beta-HCG) mRNA were observed during the secretory phase in the glandular cells of the endometrium. The results were confirmed by Western blotting of secretory phase endometrium extracts and assessment of the functional secretory capacity of primary endometrial cultures. Polymerase chain reaction (PCR) investigations showed a positive result in the secretory phase. We postulate that, based on the very close morphological interrelation between the uterus and the ovary, the beta-HCG of the endometrium is the primary factor for the maintenance of the corpus luteum and early pregnancy.

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