Association of decreased calcium-sensing receptor expression with proliferation of parathyroid cells in secondary hyperparathyroidism

BACKGROUND: The down-regulation of both calcium-sensing receptor (CaSR) and vitamin D receptor (VDR) in parathyroid (PT) glands of secondary hyperparathyroidism (HPT) caused by chronic renal failure has been associated with PT hormone hypersecretion as well as PT hypergrowth. To clarify the predominance of decreased expression of CaSR and VDR in the high proliferative activity of PT glands, we examined the relationship between the expression of both receptors and proliferative activity in human PT glands. METHODS: Serial sections of 56 PT glands, including 52 glands from secondary HPT and 4 normal PT glands resected together with thyroid carcinoma, were examined immunohistochemically with specific antibodies against CaSR, VDR, and Ki67. The Ki67-positive cell number was counted and expressed as the Ki67 score. The CaSR and VDR expressions were semiquantitatively analyzed. RESULTS: The expressions of both CaSR and VDR were markedly decreased in PT glands of secondary HPT, while the Ki67 score was significantly higher than it was in normal controls. When hyperplastic glands were classified into two subgroups, with [N(+)] or without [N(-)] nodular formation, CaSR expression was significantly decreased in N(+), while VDR expression was not different. Multiple regression analyses revealed that the decreased expression of CaSR could contribute significantly to the high proliferative activity, even if VDR expression was taken into account. CONCLUSION: The decrease in CaSR expression is associated with the high proliferative activity of PT glands in secondary HPT, independently of the decreased VDR expression. These findings provide a new insight into the pathogenesis of PT hyperplasia, which is refractory to vitamin D therapy in patients with severe secondary HPT.     

Coronary artery bypass surgery in a patient with myasthenia gravis

A 73-year-old man with myasthenia gravis required quadruple coronary artery bypass grafting due to triple-vessel disease. Anesthetic management was performed with general anesthesia using a reduced dose of muscle relaxant with the aid of a neuromuscular transmission monitor. He was extubated 14 hrs after surgery without difficulty under this monitor. His postoperative course was uneventful. A patient with myasthenia gravis who required coronary artery bypass surgery was successfully performed by the deliberate preoperative evaluation of patient's myasthenic and cardiac status, and by the careful perioperative management.     

Malignant B-lymphoid cells with bone lesions express receptor activator of nuclear factor-kappaB ligand and vascular endothelial growth factor to enhance osteoclastogenesis.

PURPOSE: Receptor activator of nuclear factor-kappaB ligand (RANKL) is a key mediator of osteoclastogenesis. Because certain types of tumor cells aberrantly express RANKL, and because bone destruction also develops in B-cell lymphomas of bone origin, we investigated RANKL expression and the mechanisms of osteoclastogenesis in B-lymphoid neoplasms. EXPERIMENTAL DESIGN AND RESULTS: Immunohistochemistry of bone specimens resected from patients with primary B-cell lymphoma of bone with bone destruction revealed that lymphoma cells express RANKL as well as vascular endothelial cell growth factor (VEGF). The tumor cells isolated from the bone specimens enhanced osteoclastogenesis in vitro. In contrast, B-cell lymphoma infiltrating to the bone marrow without bone destruction did not express RANKL. Both RANKL and VEGF were expressed by a portion of B-lymphoid cell lines, including Daudi and IM-9. These RANKL-expressing tumor cells enhanced osteoclastogenesis from RAW264.7 cells and human monocyte-derived preosteoclasts in the absence of stromal cells/osteoblasts in a RANKL-dependent manner. Furthermore, conditioned media from Daudi cells enhanced transmigration of preosteoclasts that was inhibited by anti-VEGF antibody, suggesting that tumor cell-derived VEGF mediates recruitment of osteoclast precursors. Moreover, cocultures of B-lymphoid cell lines with osteoclasts enhanced the growth of B-lymphoid cells. CONCLUSIONS: Some malignant B cells aberrantly express functional RANKL as well as VEGF to enhance osteoclastogenesis. The coexpression of RANKL and VEGF may also contribute to the close cellular interactions with osteoclastic cells, thereby forming a vicious cycle between osteoclastic bone destruction and tumor expansion in bone.     

Hemodynamic assessment of the Carpentier-Edwards pericardial valve compared with the St. Jude Medical valve in the aortic position using dobutamine-stress echocardiography

To assess the hemodynamic performance of the prosthetic valve in the aortic position, we examined dobutamine-stress echocardiography (DSE) to the patients underwent AVR with CEP valve or SJM valve. In 23 mm size, there were no significant differences between CEP group and SJM group in Peak velocity of the aortic jet (PV), peak pressure gradient (PPG) and effective orifice area (EOA). On the other hand, in 21 mm size, PV and PPG of the CEP group were significantly lower than those of the SJM group after DSE. The EOA of the CEP group was significantly larger than that of the SJM group after DSE. Our results suggest that the hemodynamic function of the CEP valve is superior to that of the SJM valve especially in small aortic annuli.     

Recurrent plexiform schwannoma involving the carotid canal

Plexiform schwannoma (PS) is a rare variety of benign nerve sheath tumor characterized by a multinodular plexiform growth pattern. PS is usually confined to the head and neck or skin. The pre-operative diagnosis of PS is difficult, and this has lead to a common misdiagnosis as a schwannoma. In addition, studies have indicated that an incomplete resection of PS often results in tumor recurrence. Here we describe a rare case of PS presented in the parapharyngeal space. Our case involved a 36-year-old man with swelling of the pharynx, who presented with a soft cervical mass. MRI revealed a multinodular mass in the left parapharyngeal space, and further pathological diagnosis by the referral hospital indicated schwannoma. A cervical approach was taken and the tumor was removed with preservation of the nerve sheath by intracapsular resection. The tumor recurred within one year after the first surgery in the same lesion of the left parapharyngeal space. The second surgical approach was a combination of a facial dismasking flap and trans-pterygopalatine fossa. The mass was resected completely, and the diagnosis of PS was confirmed by histopathology. While schwannoma commonly occurs in the head and neck, parapharyngeal space PS is rare, and pre-operative pathological diagnosis of PS is difficult. MRI studies of PS revealed distinctive features that we found useful in pre-operative diagnosis. Intracapsular resection of PS with nerve preservation has a very high recurrence rate of the tumor. Therefore, if MRI findings suggest PS we recommend removing the tumor completely without nerve preservation will offer the most curative outcome.     

Surgical Cardiac Sympathetic Denervation for Ventricular Arrhythmias: A Systematic Review

Ventricular arrhythmias are potentially life-threatening disorders that are commonly treated with medications, catheter ablation and implantable cardioverter defibrillator (ICD). Adult patients who continue to be symptomatic, with frequent ventricular arrhythmia cardiac events or defibrillation from ICD despite medical treatment, are a challenging subgroup to manage. Surgical cardiac sympathetic denervation has emerged as a possible treatment option for people refractory to less invasive medical options. Recent treatment guidelines have recommendedcardiac sympathectomy for ventricular tachycardia (VT) or VT/fibrillation storm refractory to antiarrhythmic medications, long QT syndrome, and catecholaminergic polymorphic VT, with much of the data pertaining to pediatric literature. However, for the adult population, the disease indications, complications, and risks of cardiac sympathectomy are less understood, as are the most effective surgical cardiac denervation techniques for this patient demographic. This systematic review navigates available literature evaluating surgical denervation disease state indications, techniques, and sympathectomy risks for medically refractory ventricular arrhythmia in the adult patient population.