Multicystic dysplastic kidney: observations of contralateral disease in the fetal population

To evaluate multicystic dysplastic kidney (MDK) and associated contralateral renal abnormalities in the fetal population, 27 cases detected and followed in utero were reviewed retrospectively. The sonographic assessment included estimation of amniotic fluid volume and interval growth, evaluation for non-genitourinary anomalies, and postnatal follow-up study. Contralateral renal anomalies were detected in 41% of the fetuses and included obstruction of the ureteropelvic junction, renal agenesis, renal hypoplasia, and bilateral MDK. The incidences of these malformations were compared with results of earlier studies of MDK in the pediatric and adult populations. Lethal anomalies, such as bilateral MDK and MDK associated with contralateral agenesis, are common (19% and 11%, respectively) in the fetal population; obstruction of the contralateral ureteropelvic junction, a nonlethal anomaly, was seen less commonly (7%). Perinatal death from lethal abnormalities may spuriously raise the incidence of nonlethal contralateral abnormalities in the pediatric and adult populations. Contralateral mild fetal pyelectasis, found in 15% of fetuses with MDK, was not clinically significant.     

Resolving duodenal-jejunal hematoma in abused children

Acute intramural duodenal-jejunal hematoma is a classical finding in the battered child syndrome. The radiographic findings of a large obstructing intramural mass associated with the "coiled-spring" appearance generally raise the question of child abuse in any patient without appropriate accidental injury. In this study the radiologic features of resolving duodenal-jejunal hematoma are detailed in five abused children. The results show that the coiled-spring appearance is an acute phenomenon associated with a well-localized intramural hematoma. In the resolving phase, localized mural masses in the lateral aspect of the descending duodenum and fold thickening are indications of prior intramural hemorrhage. When these radiologic features are encountered in a child with nonspecific abdominal complaints, child abuse should be suspected. Furthermore, in patients with suspected occult trauma, resolution of abdominal symptoms should not deter the radiologist from performing an upper gastrointestinal tract series, which may provide evidence of child abuse.     

Increased plasma thyroid stimulating hormone in treated congenital hypothyroidism: relation to severity of hypothyroidism, plasma thyroid hormone status, and daily dose of thyroxine

Plasma thyroid stimulating hormone (TSH) concentrations obtained during the first four years of treatment in 418 children with congenital hypothyroidism, identified by neonatal screening, were examined in relation to paired measurements of plasma thyroxine (n = 1945), free thyroxine (n = 836), triiodothyronine (n = 480), and free triiodothyronine (n = 231), and estimated daily dose of thyroxine at the time of blood sampling. Overall, plasma TSH was above 7 mU/l in 1280 out of 2960 samples (43%); the percentage was not related to severity of hypothyroidism at diagnosis. Mean values for thyroxine and free thyroxine, and to a lesser extent free triiodothyronine, were consistently lower in samples with TSH concentrations over 7 mU/l and this was the case in patients with either severe or less severe hypothyroidism. Raised TSH concentrations were also associated with lower mean doses of thyroxine (micrograms/kg/day) but here the mean doses of thyroxine in children with severe hypothyroidism were higher than in the children with less severe hypothyroidism. The mean dose of thyroxine associated with low/normal TSH values was highest in the first 6 months and fell progressively. Thyroxine dose was significantly related to thyroxine and free thyroxine concentrations but not to triiodothyronine and free triiodothyronine and the latter appeared to be of limited value as measures of plasma thyroid hormone status during treatment.     

Thrombomodulin, an endothelial anticoagulant protein, is absent from the human brain

Protein C activation by thrombin is significantly accelerated by the endothelial cell cofactor, thrombomodulin. In this study, we have developed a radioimmunoassay for thrombomodulin and have measured the cofactor content in several human tissues. The assay method detects as little as 2 ng of thrombomodulin. The highest thrombomodulin content was found in lung and placenta, but the antigen was also detected in spleen, pancreas, liver, kidney, skin, heart, and aorta. Unexpectedly, thrombomodulin was absent from brain. Extracts from cerebral cortex, cerebellum, centrum semiovale, midbrain, basal ganglia, pons, and medulla were devoid of thrombomodulin. In contrast, thrombomodulin antigen is present in extracerebral intracranial vessels, including basilar and internal carotid arteries and choroid plexus, as well as in endothelium of the pia-arachnoid.     

Computational analyses and design improvements of graft-to-vein anastomoses

For hemodialysis patients, arteriovenous grafts are omnipresent. Unfortunately, a large percentage of such grafts fail within the first year after surgery because of occlusive lesions mainly at the venous anastomotic site. It is textbook knowledge that critical values of certain hemodynamic parameters, such as low (oscillatory) wall shear stresses, large sustained wall shear stress gradients, significant changes in wall shear stress angles, excessive radial pressure gradients, etc., play significant roles in the onset and/or development of vascular diseases. The idea is to geometrically design graft-to-vein configurations such that aggravating flow patterns are reduced, and hence stenotic developments are minimized. Focusing on a new blood rheological model in conjunction with three graft-to-vein anastomotic configurations, that is, a base case, the Bard-IMPRA Venaflo graft, and a new graft-end design, the corresponding transient laminar 3-D hemodynamics are numerically simulated and compared. The design criterion for the best performance of these junction geometries is the most significant reduction in locally disturbed flow as expressed by equally weighted indicator functions for the onset and progression of stenotic developments. As a result of this comparison study, quantitative recommendations for arteriovenous loop graft designs toward increased patency rates are provided. The resulting improved graft design will be scrutinized in clinical trials.     

Transport and Deposition of Micro-Aerosols in Realistic and Simplified Models of the Oral Airway

A number of in vivo, in vitro and numerical studies have considered flow field characteristics and micro-particle deposition in the oral airway extending from the mouth through the larynx. These studies have highlighted the effects of flow rates, turbulence and particle characteristics on deposition values in realistic and simplified geometries. However, the effect of geometry simplifications on regional and local deposition patterns remains largely un-quantified for the oral airway and throughout the respiratory tract. The objective of this study is to assess the effects of geometry simplifications on regionally averaged and local micro-aerosol deposition characteristics in models of the extrathoracic oral airway. To achieve this objective, a realistic model of the oral airway has been constructed based on CT scans of a healthy adult in conjunction with measurements reported in the literature. Three other geometries with descending degrees of physical realism were constructed based on successive geometric simplifications of the realistic model. A validated low Reynolds number (LRN) k–ω turbulence model was employed to simulate laminar, transitional and fully turbulent flow regimes for 1–31 μm particles. Geometric simplifications were found to have a significant effect on aerosol dynamics, hot spot formations and cellular-level deposition values in the extrathoracic airway models considered. For all models, regional deposition efficiency results were found to be approximately within one standard deviation of available experimental data when plotted as a function of Stokes number. The realistic geometry provided the best predictions of regional deposition in comparison to experimental data as a function of particle diameter. Considering localized deposition, maximum deposition enhancement factors, which represent the ratio of local to total deposition, were one to two orders of magnitude higher for the realistic model. Geometric factors that significantly contributed to enhanced particle localization in the realistic model include a triangular-shaped glottis and a dorsal-sloped trachea. Therefore, highly realistic models of the oral airway geometry may be necessary to evaluate localized deposition patterns and hot spot formations, which are critical for accurately predicting cellular-level dose.     

Perioperative Quality Initiative consensus statement on intraoperative blood pressure,risk and outcomes for elective surgery

Background

Intraoperative mortality is now rare, but death within 30 days of surgery remains surprisingly common. Perioperative myocardial infarction is associated with a remarkably high mortality. There are strong associations between hypotension and myocardial injury, myocardial infarction, renal injury, and death. Perioperative arterial blood pressure management was thus the basis of a Perioperative Quality Initiative consensus-building conference held in London in July 2017.

In vivo and in vitro MR imaging of renal tumors: histopathologic correlation and pulse sequence optimization

Magnetic resonance (MR) imaging has given mixed results in the detection of renal masses. To identify the reasons for this and to determine the optimal pulse sequences for evaluating renal tumors, the authors imaged 12 primary renal tumors in vivo and 17 in vitro at 0.35 T. Histopathologic findings for each specimen were closely correlated with the MR images. Four of seven solid tumors imaged in vivo were isointense with surrounding normal renal parenchyma at all pulse sequences. The other three tumors were hyperintense in vivo at T2-weighted sequences. At heavily T2-weighted sequences eight solid tumors were hyperintense in vitro and four were hypointense. There was no correlation between signal intensity and specific tissue type or histologic pattern for solid tumors. The five cystic tumors were well seen both in vivo and in vitro on T2-weighted images. However, the signal intensity of the cyst fluid was an unreliable indicator of benignancy. SE MR imaging at 0.35 T has significant limitations in the detection of solid renal masses.     

Human platelet cytoskeletons: specific content of glycolipids and phospholipids

The lipid composition of platelet cytoskeletons was analyzed. Triton X- 100 (0.5%) was used to prepare cytoskeletons from thrombin-treated platelets. The lipid/protein ratio of platelet cytoskeletons was 0.260 and the phospholipid/protein ratio was 0.177, which were comparable to the ratios present in platelets. However, there was a selective enrichment of platelet lipids in platelet cytoskeletons. Only 2 of the 5 major platelet phospholipids were detected. About 14% platelet sphingomyelin and 2% platelet phosphatidylcholine were present in platelet cytoskeletons. Only 1 of the 4 platelet neutral glycolipids, trihexosyl ceramide, was detected and was about 7% of that in intact platelets. Two percent of platelet hematoside, the predominant ganglioside in platelets, was found in cytoskeletons. Six percent of platelet cholesterol was present in platelet cytoskeletons, while no other neutral lipid could be detected. The study demonstrates that the lipid/protein ratio of platelet cytoskeletons is similar to that in platelets, but the composition of cytoskeleton lipids is specific and distinctly different from that in platelets. The selective glycolipid and phospholipid composition of cytoskeletons may be important for cytoskeleton and platelet function.     

Detecting fetomaternal hemorrhage: a comparison of five methods

Appropriate postpartum administration of Rh immune globulin relies on sensitive detection and accurate quantitation of fetomaternal hemorrhage (FMH). Recently, the microscopic Du test (micro Du) enhanced with polyethylene glycol (PEG Du) and flow cytometry (FC) have been advocated for this purpose. Three qualitative methods (micro Du, rosette test, and PEG Du) and two quantitative methods (acid elution and FC) for assessing FMH were evaluated with particular attention given to PEG Du and FC. In vitro studies comprised 10 series of dilutions of D+ cord cells in D- adult cells to yield D+ cell concentrations of 0.06, 0.12, 0.25, 0.50, 0.75, 1.0, and 2.0 percent. Additionally, 26 postpartum samples were tested. Of the qualitative techniques, the micro Du test was the least sensitive with 20 percent false-negative results occurring at 0.5 percent fetal cells. The PEG Du test was only slightly more sensitive and offered no clinical advantage. The rosette test was the most sensitive, consistently detecting fetal cells at concentrations of 0.25 percent or greater. FC and acid elution showed similar results, with good correlation obtained between measured and expected quantities of fetal cells (r = 0.99 and 0.96, respectively). One of 26 postpartum samples was positive by all screening techniques; acid elution and FC detected 0.3-percent concentrations of fetal cells and 0.17-percent concentrations of D+ cells, respectively. Although acid elution is a more commonly used method for quantitating FMH, FC offers an acceptable alternative that is capable of analyzing large numbers of cells with objectivity and reproducibility.