Gadolinium contrast-enhanced MRI reveals cystic lateral semicircular canal contents

Conclusion: Contrast-enhanced magnetic resonance imaging (MRI) reveals variations in the endolymphatic morphology of the cystic lateral semicircular canal (CLSC) that correlate with inner ear function. This report is the first to suggest a relationship between the morphology and function of this common inner ear malformation in clinical cases. Objectives: This study investigated the radiological and functional findings of a common inner ear malformation using computed tomography (CT), gadolinium contrast-enhanced magnetic resonance imaging (MRI), caloric testing, and cervical and ocular vestibular evoked myogenic potential (VEMP) testing. Method: Four ears in three patients who were radiologically diagnosed with a CLSC and a normal cochlea on high-resolution CT and contrast-enhanced MRI were included. Semicircular canal and vestibular functions were analyzed using the caloric test and cervical and ocular VEMP testing. Results: Unilateral and bilateral cystic canals were found in two and one patients, respectively. In the first patient, the malformed vestibule and cystic space were separate on imaging, and perilymph filled the cystic space. The functional test results were normal. In the second patient, endolymph filled both cystic spaces, and the functional responses were poor. In the third patient, endolymph filled the cystic space, and the ear did not respond during functional testing.     

Glucosamine enhances platelet-derived growth factor-induced DNA synthesis via phosphatidylinositol 3-kinase pathway in rat aortic smooth muscle cells

Vascular smooth muscle cells play a key role in the development of atherosclerosis. Culture of vascular smooth muscle A10 cells with high glucose for 4 weeks enhanced platelet-derived growth factor (PDGF)-induced BrdU incorporation. Since a long period of high glucose incubation was required for the effect, and it was inhibited by co-incubation with azaserine, the role of hexosamine biosynthesis in the development of atherosclerosis in diabetes was studied in A10 cells. Addition of glucosamine to the culture media enhanced PDGF-stimulated BrdU incorporation, and PDGF-induced tyrosine phosphorylation of the PDGF beta-receptor was increased by glucosamine treatment. Of the subsequent intracellular signaling pathways, PDGF-induced PDGF beta-receptor association with PLC gamma was not affected, whereas tyrosine phosphorylation of Shc, subsequent association of Shc with Grb2, and MAP kinase activation were relatively decreased. In contrast, PDGF-induced PDGF beta-receptor association with the p85 regulatory subunit of PI3-kinase and PI3-kinase activation were increased by 20% (P<0.01) and 36% (P<0.01), respectively. The intracellular signaling molecules responsible for the glucosamine effect were further examined using pharmacological inhibitors. Pretreatment with PLC inhibitor (U73122) had negligible effects, and MEK1 inhibitor (PD98059) showed only a slight inhibitory effect on the PDGF-induced BrdU incorporation. In contrast, pretreatment with PI3-kinase inhibitor (LY294002) significantly inhibited glucosamine enhancement of PDGF-induced BrdU incorporation. These findings suggest that glucosamine is involved in the development of atherosclerosis by enhancing PDGF-induced mitogenesis specifically via the PI3-kinase pathway.     

High-dose 131I-metaiodobenzylguanidine therapy in patients with high-risk neuroblastoma in Japan

Annals of Nuclear Medicine - The aim of the study was to investigate the outcomes and prognostic factors of high-dose 131I-metaiodobenzylguanidine (131I-MIBG) therapy in patients with refractory or...     

Dexmedetomidine-induced atrioventricular block followed by cardiac arrest during atrial pacing: a case report and review of the literature

Sinus bradycardia is a well-known consequence of stimulation of presynaptic α₂ adrenergic receptors due the adminstration of dexmedetomidine. One of the most serious adverse effects of dexmedetomidine is cardiac arrest. Some cases demonstrating such an arrest due to the indiscriminate use of this drug were recently reported. We continuously administered dexmedetomidine to a 56-year-old male patient at a rate of 0.3 μg/kg/h (lower than the recommended dose) without initial dosing for sedation in an intensive care unit. The patient had undergone open cardiac surgery and atrial pacing was maintained at a fixed rate, 90/min. The PQ interval in electrocardiography gradually prolonged during the infusion; finally, complete atrioventricular block and subsequent cardiac arrest occurred. Immediate cardiopulmonary resuscitation was carried out, including re-intubation, and recovery of spontaneous circulation was attained 15 min after the event. The patient was discharged from hospital on the 25th postoperative day without any neurological complications.     

A safe clinical system for nitric oxide inhalation therapy for pediatric patients

A safe clinical system for nitric oxide (NO) inhalation therapy was developed. The system consists of three parts: a NO controller, a NO monitor, and a patient circuit. NO gas flow and carrier gas flow are controlled by a special rust-proof thermal mass flowmeter. Standard gas quality NO gas (10,000 ppm, balance nitrogen) is used. The outlet of the NO gas tank is connected to the distal end of a heated humidifer that is very close (12 mL) to the patient, to decrease acidic water precipitation and decrease contact time between NO and oxygen (O₂). Fail-safe mechanisms to prevent the delivery of a hypoxic mixture or excessive NO concentration are incorporated. Inspiratory NO concentration is continuously monitored by a modified electrochemical NO meter. The patient circuit consists of a breathing circuit and a ventilator with a scavenging unit. A modified Mapleson D type circuit is used. Fresh gas, humidified and mixed with NO, is introduced to the patient connection port. A mechanical ventilator, either of conventional or of high-frequency oscillation type, is connected to the expiratory limb of the Mapleson D circuit. A coaxial scavenging unit including activated charcoal is placed in between the expiratory limb and the ventilator. The adjustment of inspiratory NO concentration (y) was accurate over a wide range (1–80 ppm) of concentrations (x) (y = 0.36 + 0.96x, R² = 0.999, n = 45) and showed good agreement with the chemiluminescence method. Inspiratory nitrous oxide (NO₂) concentration was less than 0.3 ppm, and acidic water accumulation as measured by NO⁻₂ and NO⁻₃ was less than 5 ppm, even at an extremely high NO concentration of 80 ppm with an F₁O₂ of 1.0 and 10 L/min of fresh gas flow. Environmental NO and NO₂ concentrations in the ICU remained below 0.005 and 0.05 ppm, respectively. This system was used clinically on 214 pediatric patients and proved to be accurate, safe, and useful. Pediatr Pulmonol. 1996; 22:174–181. © 1996 Wiley-Liss, Inc.     

Over‐expression of BACH2 is related to ongoing somatic hypermutation of the immunoglobulin heavy chain gene variable region of de novo diffuse large B‐cell lymphoma

The basic region–leucine zipper (bZip) factor BTB, CNC homology 2 (BACH2) is known to have important roles in class switch recombination and somatic hypermutation (SHM) of the immunoglobulin (Ig) gene. In this study, we investigated the relationship between the expression of BACH2 and the status of SHM of the Ig heavy chain gene variable region (IgHV) for SHM in diffuse large B‐cell lymphoma (DLBCL). We examined 20 cases of DLBCL, 13 of which were germinal center B‐cell (GCB) DLBCL and 7 were non‐GCB DLBCL. Seven cases were negative, 6 were positive (cytoplasmic expression) and 7 were strongly positive (both nuclear and cytoplasmic expression) for BACH2. Confirmed mutation (CM) was identified in 8 cases and the CM index (number of confirmed mutations per 10 subclones) was distributed from 0 to 5. A CM index of 7 strongly positive (over‐expression) cases with BACH2 were distributed from 0 to 5, and that of 7 negative and 6 positive cases were distributed from 0 to 1. Over‐expression of BACH2 was statistically related to CM index (P = 0.008). In conclusion, over‐expression of BACH2 is critical for ongoing SHM of IgHV in DLBCL, and our data suggest that BACH2 may play an essential role for SHM of the Ig gene in B‐cell lymphoma.