Experimental evaluation of a new device for percutaneous transrenal ureteral occlusion

PURPOSE: To develop a device for percutaneous transrenal ureteral occlusion. MATERIALS AND METHODS: The device was a double-body Gianturco-R?sch biliary stent constrained at the junction of the two stents to create an hourglass shape. One stent was coated with silicone. One device was percutaneously placed in each of nine pigs through a 9-F Teflon sheath. Urographic and hematologic follow-up was performed for up to 12 weeks. RESULTS: Seven pigs showed immediate, complete ureteral occlusion, and two pigs exhibited persistent incomplete high-grade obstruction. All animals exhibited varying degrees of hydronephrosis and hydroureter. No device migration was noted. Minor complications were encountered during device placement in three pigs. Mucosal folds and villus-like projections that arose from the lamina propria protruded into the lumen of the ureter at the cranial end of the covered stent and around the wire of the caudal stent. Varying degrees of mural inflammation and edema were noted. CONCLUSION: Transrenal ureteral occlusion with the described device appears to be a viable method for treating urinary fistulas.     

Immune complex-dissociated p24 antigen in congenital or perinatal HIV infection: role in the diagnosis and assessment of risk of infection in infants

Both suppressor oncogene and proliferative activity are believed to indicate colon cancer risk. The retinoblastoma (Rb) gene is a suppressor oncogene affecting cell differentiation. Retinoblastoma gene inactivation is associated with tumour development. However, the relation of the Rb protein to cell proliferation and colon tumour formation is unknown. Retinoblastoma protein quantity was correlated with proliferative activity in flat, unaffected mucosa specimens from 36 cancer patients, 21 non-cancer control subjects and in 29 tumour tissue samples from cancer patients. Nuclear Rb protein was measured by using automated CAS-200 image analysis of monoclonal antibody labelled frozen sections from fresh, surgically removed tissue. All colon cells within 15 whole crypts were imaged. Proliferative activity was also measured by using analysis with Ki-67 monoclonal antibody. Retinoblastoma protein content correlated directly with proliferative activity in flat mucosa of non-cancer control subjects (r = 0.63; P < 0.001; n = 21). A significant correlation was also found in flat mucosa specimens of non-metastatic (Duke's stages A and B) cancer patients (r = 0.52; P < 0.01; n = 22). However, Rb protein did not correlate with proliferation in flat mucosa from metastatic (Duke's stages C and D) cancer patients (r = 0.03; NS; n = 14) or in cancer tissue (r = 0.068; NS; n = 29). Mucosal Rb protein in the colon normally increases as proliferation increases. Dissociation between Rb protein and colon proliferation may occur in flat mucosa in patients with a higher risk of metastatic tumour growth. Future studies comparing Rb protein quantity and proliferative activity may help identify high-risk colon cancer patients.     

The impact of ischemic heart disease on main pulmonary artery blood flow patterns: a comparison between magnetic resonance phase velocity mapping and transesophageal color Doppler

OBJECTIVE: To give a detailed evaluation on main pulmonary artery blood velocity patterns, in patients with ischemic heart disease and to provide recommendations for pulsed Doppler sample volume placement, in order to optimize cardiac output estimation. METHODS: Using magnetic resonance phase and esophageal color Doppler velocity mapping in 12 patients with ischemic heart disease and undergoing coronary artery by-pass grafting, very similar data on pulmonary artery blood velocity patterns were provided for comparison with each other. RESULTS: Peak blood velocities were located in the inferior half of the main pulmonary artery cross-sectional area. Early after peak systole the highest velocities shifted towards the superior/left (major curvature) with a simultaneous decrease in velocities inferiorly. The velocity decrease further evolved into retrograde flow to the inferior/right (minor curvature). This feature was significantly enhanced compared to earlier findings in healthy volunteers. The mean temporal blood velocity profiles were asymmetrically skewed, thereby giving unreliable cardiac output estimates based on single point Doppler blood velocity recordings. The error incurred may amount to more than 100% in extreme cases. According to our data, optimal assessment of cardiac output should be based on multiple sample volumes placed along the inferior/right to superior/left diameter. CONCLUSIONS: MR-phase velocity mapping and multiplane transesophageal color Doppler recordings provided similar blood velocity patterns in patients with ischemic heart disease. The skewness of the mean temporal blood velocity profile is enhanced compared with healthy subjects, resulting in error in the assessment of CO by means of pulsed Doppler echocardiography. By using multiple Doppler sample volumes, the error can be minimized.     

School-screening for scoliosis. A prospective epidemiological study in northwestern and central Greece

A two-year prospective study was done to assess the prevalence and distribution of various parameters associated with scoliosis in schoolchildren in northwestern and central Greece. A total of 82,901 children (41,939 boys and 40,962 girls) who were nine to fourteen years old were screened for scoliosis. Five thousand eight hundred and three children had clinical signs of scoliosis and, of these, 4185 were referred for posteroanterior radiographs (to be made with the patient standing) because they had a positive result on the forward-bending test (a difference of more than five millimeters between the two sides of the torso as measured in the thoracic or thoracolumbar region with use of a ruler and a level plane) at the time of a second screening. The prevalence of scoliosis (defined as a curve of 10 degrees or more) was 1.7 per cent (1436 of 82,901 children), and most of the curves (1255; prevalence, 1.5 per cent) were small (10 to 19 degrees). The ratio of boys to girls was 1:2.1 over-all but varied according to the magnitude of the curve (1:1.5 for curves of less than 10 degrees, 1:2.7 for curves of 10 to 19 degrees, 1:7.5 for curves of 20 to 29 degrees, 1:5.5 for curves of 30 to 39 degrees, and 1:1.2 for curves of 40 degrees or more). Thoracolumbar curves were the most common type of curve identified, followed by lumbar curves; specifically, of the 1436 children who had a curve of at least 10 degrees, 493 (34.3 per cent) had a thoracolumbar curve, 475 (33.1 per cent) had a lumbar curve, 261 (18.2 per cent) had a thoracic curve, and 207 (14.4 per cent) had a double curve. Although most (753) of these curves were to the left, the left:right ratio varied according to the location of the apex of the curve (1:3.1 for thoracic curves, 2.0:1 for thoracolumbar curves, and 3.2:1 for lumbar curves). The cost of the screening process was negligible (estimated at thirty cents per child); however, the decreased number of operative procedures performed in children from the geographical area of our University Hospital, the identification of a large number of previously undiagnosed curves (eleven of which were treated operatively and 170 of which were treated with a brace), and the identification of children who were at high risk for progression were considered important benefits of the school-screening program.     

Acoustic emission characteristics from steels Part 2: Acoustic measurements from fracture toughness tests

Acoustic emission measurements have been made in conjunction with fracture toughness tests on nine steels of yield strengths from 247–1606 MNm⁻². Tests made under conditions where failure would be analysed in terms of linear elastic fracture mechanics (brittle behaviour) or general yielding fracture mechanics (ductile behaviour) have shown the emission characteristics at brittle and ductile failure to be significantly different. The applicability of relationships of the form (Acoustic Emission) = Const × (Fracture Toughness)ⁿ has been investigated and the effect of test piece size examined. The relative amounts of emission monitored during the tests have permitted an acoustic ‘rating’ of the steels to be made. The validity of the Kaiser effect has been demonstrated but a detrimental influence of possible corrosion/oxidation at the crack faces has been noted. The significance of the results has been assessed in terms of the application of acoustic emission to provide 100% coverage during the periodic inspection of pressure vessels.     

Discovery and evaluation of a series of 3-acylindole imidazopyridine platelet-activating factor antagonists

Studies conducted with the goal of discovering a second-generation platelet-activating factor (PAF) antagonist have identified a novel class of potent and orally active antagonists which have high aqueous solubility and long duration of action in animal models. The compounds arose from the combination of the lipophilic indole portion of Abbott's first-generation PAF antagonist ABT-299 (2) with the methylimidazopyridine heterocycle moiety of British Biotechnology's BB-882 (1) and possess the positive attributes of both of these clinical candidates. Structure-activity relationship (SAR) studies indicated that modification of the indole and benzoyl spacer of lead compound 7b gave analogues that were more potent, longer-lived, and bioavailable and resulted in the identification of 1-(N, N-dimethylcarbamoyl)-4-ethynyl-3-[3-fluoro-4-[(1H-2-methylimidazo[4,5-c] pyrid-1-yl)methyl]benzoyl]indole hydrochloride (ABT-491, 22 m.HCl) which has been evaluated extensively and is currently in clinical development.     

Flap prefabrication: effectiveness of different vascular carriers

A new experimental model of a vascular carrier to prefabricate a "secondary" island flap, the popliteal musculovascular pedicle, was developed in the rat. Using quantitative skin-surface fluorometry 30 minutes after sodium fluorescein injection and a flap survival area in the prefabricated 8 x 2.5-cm abdominal composite island flap, we compared the revascularization ability of our muscular carrier to nonrevascularized controls: the skeletonized arteriovenous pedicle and the fasciovascular pedicle. The free composite graft with no vascular carrier exhibited near-total necrosis. The skeletonized vascular pedicle demonstrated 15.2% +/- 7.8% perfusion of normal skin on dye fluorescence index measurements and 50% flap survival. The fasciovascular pedicle exhibited better revascularization, with a dye fluorescence index of 36.2 +/- 15.5 (p < 0.01) and 90% +/- 10% flap survival (p < 0.001). India ink injection study and histological examination of our model provided visual evidence of revascularization from the musculovascular pedicle, along with preservation of the carrier's muscular architecture. The musculovascular pedicle is a reliable carrier for making new, vascularized composite flaps.