Expanding Awareness of the Distribution and Biologic Potential of Ectomesenchymal Chondromyxoid Tumor

Ectomesenchymal chondromyxoid tumor is a rare neoplasm of uncertain histogenesis that typically occurs in the anterior dorsal tongue. Recent reports in the literature have described rare examples of gingival, palatal and tonsillar lesions. Histologically, ectomesenchymal chondromyxoid tumors are typically well-circumscribed, lacking overtly aggressive features. Herein we report a tumor arising in the right mandible that is morphologically and molecularly consistent with ectomesenchymal chondromyxoid tumor. This case furthers awareness of the extra-glossal distribution of this neoplasm; moreover, it suggests that a subset of these tumors have the potential for locally aggressive behaviour.Electronic supplementary materialThe online version of this article (10.1007/s12105-020-01169-5) contains supplementary material, which is available to authorized users.     

Effect of riluzole on the neurological and neuropathological changes in an animal model of cardiac arrest-induced movement disorder

Posthypoxic myoclonus and seizures precipitate as secondary neurological consequences in ischemic/hypoxic insults of the central nervous system. Neuronal hyperexcitation may be due to excessive activation of glutamatergic neurotransmission, an effect that has been shown to follow ischemic/hypoxic events. Therefore, riluzole, an anticonvulsant that inhibits the release of glutamate by stabilizing the inactivated state of activated voltage-sensitive sodium channels, was tested for its antimyoclonic and neuroprotective properties in the cardiac arrest-induced animal model of posthypoxic myoclonus. Riluzole (4-12 mg/kg i.p.) dose-dependently attenuated the audiogenic seizures and action myoclonus seen in this animal model. Histological examination using Nissl staining and the novel Fluoro-Jade histochemistry in cardiac-arrested animals showed an extensive neuronal degeneration in the hippocampus and cerebellum. Riluzole treatment almost completely prevented the neuronal degeneration in these brain areas. The neuroprotective effect was more pronounced in hippocampal pyramidal neurons and cerebellar Purkinje cells. These effects were seen at therapeutically relevant doses of riluzole, and the animals tolerated the treatment well. These findings indicate that the pathogenesis of posthypoxic myoclonus and seizure may involve excessive activation of glutamate neurotransmission, and that riluzole may serve as an effective pharmacological agent with neuroprotective potential for the treatment of neurological conditions associated with cardiac arrest in humans.     

FK506-associated thrombotic microangiopathy: report of two cases and review of the literature

BACKGROUND: FK506 is a recently developed immunosuppressant that has been useful in improving the survival of transplanted organs. Among the numerous adverse side effects of FK506, thrombotic microangiopathy (TMA) stands out as an infrequent but severe complication. METHODS: We report two cases of FK506-associated TMA and review the 19 previous reported cases. RESULTS: From these 21 cases, the reported incidence of FK506-associated TMA is between 1% and 4.7%. It is more frequent in females, and the mean age at presentation is 47 years. Eighty-one percent of the cases occurred in patients with kidney allografts, and the remaining patients had liver, heart, or bone marrow transplants. Clinically, TMA was diagnosed at an average interval of 9.3 months from the time of transplantation. Patients may be asymptomatic or may present with the full-blown picture of hemolytic uremic syndrome. All patients had an elevated serum creatinine level but did not always show signs of hemolysis. Trough levels of FK506 were not predictive for the development of TMA, but generally a reduction of drug dose correlated with kidney function improvement and disappearance of the hemolytic picture. The renal allograft biopsy provided a conclusive diagnosis in all 17 cases in which this procedure was performed. Treatment, which mainly consisted of reduction or discontinuation of FK506, anticoagulation, and/or plasmapheresis with fresh-frozen plasma exchange, resolved TMA in most patients (57%). However, in one of these patients (5%), the graft was subsequently lost due to causes unrelated to TMA, such as acute or chronic rejection. Despite treatment, one patient (5%) lost the graft due to acute rejection and persistent TMA, and three other patients (14%) who had bone marrow, heart, and liver transplants, died of multiple organ failure, probably unrelated to TMA. In the remaining four patients (19%), response to treatment was not reported. CONCLUSIONS: TMA must be considered in organ transplant patients treated with FK506 whenever kidney function deteriorates, even in the absence of microangiopathic hemolytic anemia. Although TMA usually responds to treatment, it may, in rare cases, lead to loss of kidney function or even the patient's death.     

Pharmacological similarities between native brain and heterologously expressed alpha4beta2 nicotinic receptors

1 We studied the pharmacological properties of native rat brain and heterologously expressed rat alpha4beta2 nicotinic receptors immunoprecipitated onto a fixed substrate with the anti-alpha4 antibody mAb 299. 2 Immunodepletion with the anti-beta2 antibody mAb 270 showed that 89% of the mAb-299-precipitated rat brain receptors contained beta2. 3 The association and dissociation rate constants for 30 pM +/-[3H]-epibatidine binding to alpha4beta2 receptors expressed in oocytes were 0.02+/-0.01 and 0.03+/-0.01 min-1 (+/-standard error, degrees of freedom=7 - 8) at 20 - 23 degrees C. 4 The Hill coefficients for +/-[3H]epibatidine binding to the native brain, alpha4beta2 receptors expressed in oocytes, and alpha4beta2 receptors expressed in CV-1 cells (using recombinant adenovirus) were 0.69 - 0.70 suggesting a heterogeneous receptor population. Fits of the +/-[3H]-epibatidine concentration-binding data to a two-site model gave KD s of 8 - 30 and 560 - 1,200 pM. The high-affinity sites comprised 73 - 74% of the native brain and oocyte alpha4beta2 receptor population, 85% of the CV-1 alpha4beta2 receptor population. 5 The expression of rat alpha4beta2 receptors in CV-1 cells using vaccinia viral infection-transfection resulted in a more homogeneous receptor population (Hill coefficient of 1. 0+/-0.2). Fits of the +/-[3H]-epibatidine binding data to a single-site model gave a KD of 40+/-3 pM. 6 DHbetaE (IC50=260-470 nM) and the novel nicotine analogue NDNI (IC50=7-10 microM) inhibited 30 pM+/-[3H]-epibatidine binding to the native brain and heterologously expressed alpha4beta2 receptors equally well. 7 The results show that alpha4beta2-containing nicotinic receptors in the rat brain and heterologously expressed rat alpha4beta2 receptors have similar affinities for +/-[3H]-epibatidine, DHbetaE, and NDNI.     

The SiBI connector: a new medical device to facilitate preoxygenation and reduce waste anesthetic gases during inhaled induction with sevoflurane

IMPLICATIONS: The SiBI connector is a new medical device used for vital capacity inhaled induction with sevoflurane. It allows efficient preoxygenation of patients and reduces waste anesthetic gases in the operation room during induction.     

A treatment algorithm for pneumothoraces complicating central venous catheter insertion

BACKGROUND: We investigated the role of observation or insertion of a small French pigtail catheter with Heimlich valve as alternative management to a tube thoracostomy for iatrogenic pneumothorax complicating central venous catheter (CVC) insertion. METHODS: A retrospective review of 9,637 consecutive patients who had had subclavian CVCs inserted on an outpatient basis identified 100 patients with pneumothoraces. Treatment consisted of (1) observation, (2) outpatient insertion of a Heimlich valve, or (3) inpatient tube thoracostomy. RESULTS: The median pneumothorax size was 10% (range 1% to 100%). Fifty-eight patients had observation as initial treatment, and this strategy was successful in 35 (60%). Thirty-four patients were treated initially with Heimlich valves, and this strategy was successful in 29 (85%). Tube thoracostomy as initial therapy was successful in 7 (88%) of 8 patients. Patients in who initial treatment failed were treated with insertion of a Heimlich valve or tube thoracostomy. CONCLUSION: In appropriately selected patients, pneumothorax after insertion of a subclavian CVC can be successfully managed in the outpatient setting with observation. Patients in whom observation fails can be treated with insertion of a Heimlich valve. Tube thoracostomy can be reserved for refractory PTX or emergent situations.     

Manufacturing Better Outcomes in Cardiovascular Intervention: 3D Printing in Clinical Practice Today

Purpose of review

Describe and evaluate the integration of 3D printing-related innovations into current cardiovascular treatment paradigms and examine the state of regulatory and reimbursement hurdles ahead.

Recent findings

Mounting years of clinical experience have established the utility of printed models of patient anatomy in numerous treatment and teaching scenarios, most notably as pre- and intra-procedural planning tools guiding decision-making for congenital heart disease and catheter-based interventions. In part due to a continued lack of reimbursement and under-defined (and slow to evolve) regulatory status, these use cases remain largely investigational even as they grow increasingly routine. Patients, physicians, and/or imaging centers therefore remain burdened by the associated cost to create such models, and the perceptual and decision-making enhancements, while demonstrable and significant, still may not clearly or independently justify a potentially high cost.Simulation and implantable device applications may represent a deeper well of unrealized value in cardiovascular intervention; however, further development of these applications relies on—and is throttled by—progress in material science and tissue-engineering research. The relevance of simulation applications in recent years is also now in competition with digital analogs including augmented and virtual reality. Innovative incorporation of alternative manufacturing processes such as porous scaffold infusion, injection molding, and vascular mesh forming can provide immediate access to more realistic tissue-mimicking materials and custom implantable devices, while comparable and directly printable materials continue to be developed. Tissue-engineering applications remain years if not decades away from a more substantive role in translatable clinical research. Regulatory challenges associated with in-house manufacture of implantable investigational devices are complex and subject to change, and the success of some in navigating these hurdles in non-cardiovascular applications is instructive and encouraging.

Summary

Complex geometries characterizing cardiovascular anatomy are an ideal use case for translating the perceptual advantages of printed models of patient anatomy into better decision-making, especially so in the setting of congenital or post-surgical anatomy. Procedural planning applications take further advantage of the demonstrably robust dimensional reproduction of patient anatomy, with notably rapid integration into surgical and catheter-based intervention workflows. Despite a continued lack of codification in the healthcare system, 2018 could be a milestone year for 3D printing services, pending a successful application for a CPT Category III designation.

     

Severe intravascular hemolysis following mitral valve repair

We report two cases of severe intravascular hemolysis (IVH) following mitral valve repair using a Cosgrove-Edwards ring. In both cases, the degree of mitral regurgitation (MR) seen postoperatively worsened significantly compared to intraoperative transesophageal echocardiogram. Both patients required reoperation with mitral valve replacement with immediate resolution of the hemolysis. We hypothesize that the mitral regurgitation in the setting of an inadequate mitral valve repair is responsible for the hemolysis and propose various mechanisms to explain this pathophysiology. Although IVH remains a rare complication following mitral valve repair, possible screening recommendations should be considered for early detection and treatment given the growing number of mitral valve repairs being performed.