Hyponatremia and Comparison of NT-pro-BNP Concentrations in Blood Samples from Jugular Bulb and Arterial Sites after Traumatic Brain Injury in Adults: A Pilot Study

Background  

Hyponatremia after traumatic brain injury (TBI) may influence neurological function and treatment. A causal relationship between elevated serum concentrations of Type B natriuretic peptide (BNP) and hyponatremia has been implied after subarachnoid hemorrhage and other neurosurgical disorders, although the source of BNP has not been identified. We evaluated if hyponatremia and increased BNP occur after TBI and if BNP is produced/released by the brain within 24 h after injury.     

The influence of hemodynamic forces on biomarkers in the walls of elastase-induced aneurysms in rabbits

Introduction Biological and biophysical factors have been shown to play an important role in the initiation, progression, and rupture of intracranial aneurysms. The purpose of this study was to evaluate the association between hemodynamic forces and markers of vascular remodeling in elastase-induced saccular aneurysms in rabbits. Methods Elastase-induced aneurysms were created at the origin of the right common carotid artery in rabbits. Hemodynamic parameters were estimated using computational fluid dynamic simulations based on 3-D-reconstructed models of the vasculature. Expression of matrix metalloproteinases (MMPs), their inhibitors (TIMPs) and markers of vascular remodeling were measured in different spatial regions within the aneurysms. Results Altered expression of biological markers relative to controls was correlated with the locations of subnormal time-averaged wall shear stress (WSS) but not with the magnitude of pressure. In the aneurysms, WSS was low and expression of biological markers was significantly altered in a time-dependent fashion. At 2 weeks, an upregulation of active-MMP-2, downregulation of TIMP-1 and TIMP-2, and intact endothelium were found in aneurysm cavities. However, by 12 weeks, endothelial cells were absent or scattered, and levels of pro- and active-MMP-2 were not different from those in control arteries, but pro-MMP-9 and both TIMPs were upregulated. Conclusion These results reveal a strong, spatially localized correlation between diminished WSS and differential expression of biological markers of vascular remodeling in elastase-induced saccular aneurysms. The ability of the wall to function and maintain a healthy endothelium in a low shear environment appears to be significantly impaired by chronic exposure to low WSS.     

Strategies for the Management of SVC Stent Migration into the Right Atrium

Purpose Stent migration into the right atrium is a potentially fatal complication of stenting in the venous system and is most likely to occur during the treatment of superior vena cava obstruction. Endovascular approaches that can salvage this hazardous situation are described and the keys to successful treatment are highlighted. Materials and Methods Four different strategies are reviewed: (1) snaring the stent directly, (2) angioplasty balloon-assisted snaring of the stent, (3) guide wire-assisted snaring of the stent, and (4) superior vena cava-to-inferior vena cava bridging stent. Results These techniques have been employed in the successful management of four cases. No short- or long-term complications as a result of these maneuvers have been identified. Additional treatment of the underlying disease was possible at the same time in each case. Conclusion We conclude that prompt management of right atrial stent migration is essential and can be successfully achieved by a variety of “bale-out” techniques which are within the technical range of most interventional radiologists.     

Intracranial vascular anomalies in patients with periorbital lymphatic and lymphaticovenous malformations

BACKGROUND AND PURPOSE: The purpose of this study was to determine the nature, incidence, and radiologic appearance of intracranial vascular anomalies that occur in association with periorbital lymphatic malformation (LM) and lymphaticovenous malformation (LVM). MATERIALS AND METHODS: We retrospectively reviewed clinical records and imaging studies of 33 patients ranging in age from the neonatal period to 39 years (mean age, 5.1 years; median age, 1.0 year) who were evaluated for orbital LM or LVM at our institution between 1953 and 2002. Imaging studies, including CT, MR imaging, and cerebral angiograms, were evaluated by 2 radiologists to determine morphologic features of orbital LM and to identify associated noncontiguous intracranial vascular and parenchymal anomalies, including arteriovenous malformations (AVM), cerebral cavernous malformations (CCM), developmental venous anomalies (DVA), dural arteriovenous malformations (DAVM), and sinus pericranii (SP). RESULTS: The malformation was left-sided in 70% of patients. Twenty-two patients (70%) had intracranial vascular anomalies: DVA (n = 20; 61%), CCM (n = 2; 6%), DAVM (n = 4; 12%), pial AVM (n = 1; 3%), and SP (n = 1; 3%). Arterial shunts were present in the soft tissues in 2 patients (6%). Three patients had jugular venous anomalies. Three patients (9%) had cerebral hemiatrophy, 2 (6%) had focal cerebral atrophy, and 2 had Chiari I malformation. CONCLUSIONS: Intracranial vascular anomalies, some of which are potentially symptomatic and require treatment, are present in more than two thirds of patients with periorbital LM. Initial imaging of patients with orbital LM should include the brain as well as the orbit.     

The Neuroimaging Center of the Pediatric Brain Tumor Consortium-collaborative neuroimaging in pediatric brain tumor research: a work in progress

As an essential part of the National Cancer Institute (NCI)-funded Pediatric Brain Tumor Consortium (PBTC), the Neuroimaging Center (NIC) is dedicated to infusing the study of pediatric brain tumors with imaging "best practice" by producing a correlative research plan that 1) resonates with novel therapeutic interventions being developed by the wider PBTC, 2) ensures that every PBTC protocol incorporates an imaging "end point" among its objectives, 3) promotes the widespread implementation of standardized technical protocols for neuroimaging, and 4) facilitates a quality assurance program that complies with the highest standards for image data transfer, diagnostic image quality, and data integrity. To accomplish these specific objectives, the NIC works with the various PBTC sites (10 in all, plus NCI/ National Institute of Neurological Diseases and Stroke representation) to ensure that the overarching mission of the consortium--to better understand tumor biology and develop new therapies for central nervous system tumors in children--is furthered by creating a uniform body of imaging techniques, technical protocols, and standards. Since the inception of the NIC in 2003, this broader mandate has been largely accomplished through a series of site visits and meetings aimed at assessing prevailing neuroimaging practices against NIC-recommended protocols, techniques, and strategies for achieving superior image quality and executing the secure transfer of data to the central PBTC. These ongoing evaluations periodically examine investigations into targeted drug therapies. In the future, the NIC will concentrate its efforts on improving image analysis for MR imaging and positron-emission tomography (PET) and on developing new ligands for PET; imaging markers for radiation therapy; and novel systemic, intrathecal, and intralesional therapeutic interventions.     

Tumor-induced osteomalacia: a case of diagnostic dilemma

Tumor-induced osteomalacia is typically caused by benign mesenchymal tumors of vascular or skeletal origin. Overexpression of fibroblast growth factor 23 (FGF-23) by these tumors is associated with decreased resorption of phosphate in the renal tubules. This phosphate wasting leads to the characteristic findings of hypophosphatemia and hyperphosphaturia. Chronic hypophosphatemia causes abnormal mineralization of bone, increased alkaline phosphatase and, in the longer term, osteomalacia. Localization and resection of the FGF-23-secreting tumor offers the best chance of cure. We report a case of a 74-year-old woman diagnosed with numerous fractures on bone scintigraphy. Bone biopsy confirmed osteomalacia. Biochemical investigations showed hypophosphatemia, hyperphosphaturia, and increased alkaline phosphatase, suggesting the presence of an FGF-23-secreting tumor. Biochemistry also showed hyperparathyroidism and subclinical hyperthyroidism. Thyroid and parathyroid scintigraphy were performed and showed separate areas of focally increased tracer uptake in the neck. The patient underwent octreotide scintigraphy to localize an alternative site of tumor. This showed focally increased tracer uptake in the neck and in the abdomen. The patient underwent a hemithyroidectomy, parathyroidectomy, and adrenalectomy. Histopathology showed a papillary carcinoma of the thyroid, a parathyroid adenoma, and an adrenal adenoma. Postoperatively the patient showed rapid symptomatic and biochemical improvement.     

Estimation of beta-cell mass by metabolic tests: necessary, but how sufficient?

This Perspectives in Diabetes addresses the accuracy of metabolic testing as a measure of pancreatic islet beta-cell mass in vivo in animals and in humans. The impetus for framing this question lies in the current intense interest in determining the fate of beta-cell mass in transplanted islets, i.e., does it decrease, increase, or remain the same over time, as well as ascertaining whether drugs that enhance incretin levels, and consequently enhance glucose-induced insulin secretion, might also preserve beta-cell mass. An important methodology recently making scientific strides in this arena is positron emission tomography (PET). The central question this Perspectives in Diabetes raises is whether it is likely that PET will provide significant advantages over the metabolic methods already in hand and routinely used to estimate beta-cell mass. This article examines the fidelity with which published metabolic data correlate with independent measures of beta-cell mass across multiple species. Correlation coefficients in the general range of r = 0.80 are routinely obtained and are robust for in vivo research. Whether PET can significantly improve on these correlations, given its inherent limitations in measurement sensitivity, remains to be seen. It is clear that investigators developing PET methodology to estimate beta-cell mass should at the same time incorporate metabolic measures into their studies so that side-by-side comparisons of the accuracy of the two experimental approaches can be made.     

Tick-borne flaviviruses: dissecting host immune responses and virus countermeasures

The tick-borne encephalitis (TBE) serocomplex of viruses, genus Flavivirus, includes a number of important human pathogens that cause serious neurological illnesses and hemorrhagic fevers. These viruses pose a significant public health problem due to high rates of morbidity and mortality, their emergence to new geographic areas, and the recent rise in the incidence of human infections. The most notable member of the TBE serocomplex is tick-borne encephalitis virus (TBEV), a neurotropic flavivirus that causes debilitating and sometimes fatal encephalitis. Although effective prophylactic anti-TBEV vaccines have been developed, there is currently no specific treatment for infection. To identify new targets for therapeutical intervention, it is imperative to understand interactions between TBEV and the host immune response to infection. Interferon (IFN) has a critical role in controlling flavivirus replication. Dendritic cells (DCs) represent an early target of TBEV infection and are major producers of IFN. Thus, interactions between DCs, IFN responses, and the virus are likely to substantially influence the outcome of infection. Early IFN and DC responses are modulated not only by the virus, but also by the tick vector and immunomodulatory compounds of tick saliva inoculated with virus into the skin. Our laboratory is examining interactions between the triad of virus, tick vector, and mammalian host that contribute to the pathogenesis of tick-borne flaviviruses. This work will provide a more detailed understanding of early events in virus infection and their impact on flavivirus pathogenesis.