Bilateral versus unilateral sudden sensorineural hearing loss.

OBJECTIVES: To analyze the clinical characteristics and treatment results between bilateral (bi-) and unilateral (uni-) sudden sensorineural hearing loss (SSNHL). STUDY DESIGN AND SETTING: A retrospective study. METHODS: Three hundred twenty-four patients with SSNHL were classified into two groups; simultaneous bi-SSNHL (n = 16) and uni-SSNHL (n = 308). We compared clinical characteristics, medical history, hearing level, and treatment results between the 2 groups. RESULTS: The incidence of bi-SSNHL was 4.9 percent of overall patients with SSNHL. Bi-SSNHL occurs more commonly in patients of older age, with preexisting diabetes mellitus, and lipid panel abnormalities compared with uni-SSNHL. Ten patients (62.5%) in the bi-SSNHL group showed hearing recovery in 1 or both ears compared with 56.5 percent of patients with uni-SSNHL. Only 12 (37.5%) of all 32 ears recovered in bi-SSNHL, which was significantly lower than in uni-SSNHL. CONCLUSION: Bi-SSNHL has a very low incidence and lower recovery rate than uni-SSNHL. Recognition of similarities and differences between bilateral and unilateral SSNHL can help in counseling and managing the patients.     

CT analysis and histopathology of bone remodeling in patients with chronic rhinosinusitis.

OBJECTIVE: To evaluate the findings of computed tomography (CT) and histopathology of the bulla ethmoidalis as objective markers of bone remodeling in chronic rhinosinusitis (CRS). METHODS: Preoperative ostiomeatal unit (OMU) scans and histopathologic findings of the bulla ethmoidalis were performed on 23 patients (39 sides) undergoing endoscopic sinus surgery for CRS. Lund-Mackay scores and Hounsfield units (HU) of the bulla were checked in coronal CT scans. The pathologist graded the severities of the mucosal and bony changes in histopathology. Statistical analysis was performed using Mann-Whitney U test and Spearman correlation coefficient (r). RESULTS: The HU values of the bulla were significantly increased with higher Lund-Mackay scores in OMU CT (r = 0.405, P = 0.01). The bony grades in histopathology were significantly increased with higher mucosal grades (r = 0.821, P = 0.0001). These findings in CT scans and histopathology were well correlated with each other (r > 0.3, P < 0.05). CONCLUSION: HU may be a useful objective marker of bone remodeling in chronic rhinosinusitis.     

Disturbances of bone growth and development

"What is growth anyway? Can one talk about positive growth in childhood, neutral growth in maturity, and negative growth in old age?" Our goal is to help promote normal positive growth in infants and children. To achieve this, we must be cognizant of the morphologic changes of both normal and abnormal bone formation as they are reflected in the radiographic image of the skeleton. The knowledge of the various causes and the pathophysiologic mechanisms of the disturbances of bone growth and development allows us to recognize the early radiographic manifestations. Endocrine and metabolic disorders affect the whole skeleton, but the early changes are best seen in the distal ends of the femurs, where growth rate is most rapid. In skeletal infections and in some vascular injuries two-or three-phase bone scintigraphy supercedes radiography early in the course of the disease. MRI has proved to be very helpful in the early detection of avascular bone necrosis, osteomyelitis, and tumor. Some benign bone tumors and many bone dysplasias have distinct and diagnostic radiographic findings that may preclude further studies. In constitutional diseases of bone, including chromosomal aberrations, skeletal surveys of the patient and all family members together with biochemical and cytogenetic studies are essential for both diagnosis and genetic counseling. Our role is to perform the least invasive and most informative diagnostic imaging modalities that corroborate the biochemical and histologic findings to establish the definitive diagnosis. Unrecognized, misdiagnosed, or improperly treated disturbance of bone growth can result in permanent deformity usually associated with disability.     

Autonomic dysregulation as a basis of cardiovascular, endocrine, and inflammatory disturbances associated with obstructive sleep apnea and other conditions of chronic hypoxia, hypercapnia, and acidosis

Obstructive sleep apnea has traditionally been viewed as a structural disease. A multitude of systemic endocrine and cardiovascular abnormalities have been previously attributed to the prevalence of obesity in these patients. A growing body of clinical evidence, however, points to a relationship between sleep apnea and its systemic abnormalities independent of obesity. We hypothesize that this association is based on a maladaptive autonomic response of chemoreceptors, reacting to the hypoxia, hypercapnia, and acidosis of sleep apnea. The elevated sympathetic response triggers an inflammatory cascade that results in a myriad of downstream consequences including insulin resistance, hypertension, diabetes, atherosclerosis and metabolic syndrome. The sympathetic bias and endocrine disturbances may further exacerbate sleep disturbance in a potentially pernicious cycle. Our proposal may extend to any chronic respiratory or metabolic conditions that manifest hypoxia, hypercapnia, and acidosis and elicit a maladaptive autonomic and inflammatory response.     

Immunocytochemical localization of zinc transporter 3 in the ependyma of the mouse spinal cord

We report, for the first time, the light microscopical and ultrastructural appearance of ZnT3-immunoreactivities in the ependymal cells of the central canal of the mouse spinal cord. Light microscopy revealed the presence of ZnT3-immunoreactive (Ir) ependymal cells in 1 microm thick epon sections stained by the ABC method. The ZnT3-Ir cells were observed at all levels of the spinal cord, but were a little more numerous in lumbosacral segments than in cervicothoracic segments. The ZnT3-Ir cells had large, ovoid nuclei with abundant cytoplasm, and protruded into the lumen of the central canal. Our ultrastructural findings suggest that the ZnT3-Ir ependymal cells possess secretory activity directed towards the central canal. We propose that they may play a role in the trans-ependymal mechanism responsible for zinc homeostasis between cerebrospinal fluid and the central area of the gray matter.     

Combined effects of inhaled nitric oxide and a recruitment maneuver in patients with acute respiratory distress syndrome

Nitric oxide (NO) inhalation therapy has been employed in the management of acute respiratory distress syndrome (ARDS), in order to improve oxygenation. Several factors have been implicated as being responsible for the action of inhaled NO. Alveolar recruitment methods, such as prone positioning and a sufficient positive end expiratory pressure (PEEP), have been identified as having a positive impact on the NO response. A Recruitment maneuver (RM) was introduced for the treatment of ARDS, along with a lung protective strategy. Here, we hypothesized that a RM may further augment the oxygenation of patients treated with NO inhalation. Therefore, the effects of the inhalation of NO, either in combination with a RM, or separately, were evaluated on patients with ARDS for their enhancing action. 23 patients with ARDS were enrolled, and divided into three groups. The patients in group 1 (n=11) were treated with 5 ppm NO via inhalation, followed by a RM, applying a sustained inflation pressure of 30 - 35 cmH2O for 30 seconds. Group 2 (n=6) received a RM alone, while group 3 (n=3) was treated with NO inhalation alone. The oxygenation and hemodynamic parameters were obtained prior to, and 2, 12, and 24 h after, the respective treatment procedures. For group 1, the PaO2/FiO2 increased from its initial value of 171.8 +/- 67.8 to 203.2 +/- 90.0 2 h after NO inhalation. Further improvement was noted with the continual application of the RM reaching, 215.5 +/- 74.6 (p=0.05) and 254.2 +/- 109.5 (p < 0.05), after 12 and 24 h, respectively. Initially 7 of the subjects did not respond to NO inhalation, but 3 of these non-responders changed into responders 12 h after the RM. The changes in the PaO2/FiO2 from baseline at each time period were greater in group 1 than in the other groups, but with no statistical significance. The hemodynamics of the patients was not significantly altered during the entire study period. We conclude that the combined application of NO inhalation and a RM could be beneficial and safe for patients with ARDS, showing an enhancing effect in improvement of oxygenation.     

Treatment of motoneuron degeneration by intracerebroventricular delivery of VEGF in a rat model of ALS

Neurotrophin treatment has so far failed to prolong the survival of individuals affected with amyotrophic lateral sclerosis (ALS), an incurable motoneuron degenerative disorder. Here we show that intracerebroventricular (i.c.v.) delivery of recombinant vascular endothelial growth factor (Vegf) in a SOD1(G93A) rat model of ALS delays onset of paralysis by 17 d, improves motor performance and prolongs survival by 22 d, representing the largest effects in animal models of ALS achieved by protein delivery. By protecting cervical motoneurons, i.c.v. delivery of Vegf is particularly effective in rats with the most severe form of ALS with forelimb onset. Vegf has direct neuroprotective effects on motoneurons in vivo, because neuronal expression of a transgene expressing the Vegf receptor prolongs the survival of SOD1(G93A) mice. On i.c.v. delivery, Vegf is anterogradely transported and preserves neuromuscular junctions in SOD1(G93A) rats. Our findings in preclinical rodent models of ALS may have implications for treatment of neurodegenerative disease in general.