Effect of flumazenil on hypoglossal and phrenic nerves activities in rabbits

BACKGROUND: Upper airway obstruction and inadequate ventilation often arise during sedation and anesthesia by benzodiazepines (Bz). Flumazenil antagonizes these effects of active benzodiazepines on the central nervous system. To estimate the influence of flumazenil on the endogenous Bz system related respiratory control, we studied the effect of flumazenil and diazepam on the neural activity and the respiratory response caused by a brief (60 sec) respiratory arrest (RA) manifested in the hypoglossal nerve (HG) and the phrenic nerve (PH) activities in rabbits. METHODS: Experiments were performed on adult rabbits which were vagotomized, paralyzed and artificially ventilated with 50% N2O, 50% oxygen and 0.5% sevoflurane. We evaluated and compared the effects of the sequential administrations of flumazenil and diazepam on the peak amplitude (AMP) as well as the root mean square (RMS) of HG and PH, and respiratory cycle (Tc). RESULTS: Flumazenil by itself increased HG activity more than PH activity with no influence on Tc. But it was not dose-related. Previous administration of flumazenil in total dose of 0.25 mg x kg(-1) could not prevent the anticipated respiratory depression caused by diazepam 2.0 mg x kg(-1). These depressions are greater in HG activity than in PH activity. Additional flumazenil 0.15 mg x kg(-1) following the administration of diazepam promptly reversed these inhibitory effects on HG activity beyond the control level. The same dose of flumazenil, however, did not reverse PH activity sufficiently. RA response was characterized by raised AMPs and augmented RMSs (deltaAMPs, deltaRMSs) with marked prolongation in Tc (deltaTc). Flumazenil and diazepam did not seem to have any influence upon these RA responses. There was a significant change in cardiovascular parameters with the tested dosages of flumazenil and diazepam, but the change was in the normal physiological range. CONCLUSIONS: These results suggest the possibility that the endogenous benzodiazepine system is likely to play an inhibitory role in the regulation of respiration, especially in the maintenance of upper airway patency but the system is unrelated to the chemosensitive-respiratory control.     

Aortic root redissection associated with the use of gelatin-resorcin-formalin glue following surgical treatment for acute type A aortic dissection; report of a case

A late redissection case of the aortic root after total arch replacement for acute Stanford type A aortic dissection was reported. A 55-year-old male was treated with total arch replacement for acute Stanford type A aortic dissection. The aortic valve was bicuspid valve, and the right coronary leaflet was prolapsed because of the dissection of right and non coronary cusp. Resuspension of the commissure and the fixation of the dissected aortic wall with gelatin-resorcin-formalin (GRF) glue was performed during the operation. The initial postoperative course was uneventful and the patient discharged 52 days after the operation. Redissection of aortic root was pointed out on the computed tomography (CT) 3.5 years after the operation. As the second operation, the aortic root replacement was performed. Coronary artery bypass for right coronary artery was simultaneously performed with right internal thoracic artery because the right coronary ostium was stenotic and showed ischemic change on electrocardiogram monitor during the operation. The redissection was seen on the right coronary sinus, which was fixed by the GRF glue during the first operation. The pathological study showed the migration of macrophages and the tear of the fibrous tissue. These findings was thought to be associated with the use of the GRF glue. Careful use of the GRF glue for the fixation of the dissected aorta during the surgical treatment for the Stanford type A aortic dissection was thought to be important.     

Primary pericardial malignant mesothelioma with incomplete endocardial cushion defect; report of a case

Primary pericardial malignant mesothelioma is rare tumor and its prognosis is quite poor due to its late presentation and difficulty of complete resection. We describe a rare case of primary pericardial malignant mesothelioma in a 46-year-old female with incomplete endocardial cushion defect (ECD). Incidentally, we found 2 masses in the pericardial spaces after pericardiectomy. We have successfully removed these 2 masses en bloc and performed a total repair of incomplete ECD. Pathologically, these masses were a primary pericardial malignant mesothelioma. This patient is doing well 4 months after surgery without any evidence of recurrence despite reported poor prognosis of "primary pericardial malignant mesothelioma".     

Huge endocrine tumor of the pancreas

We report a case of a huge endocrine tumor of the pancreas. A 76-year-old woman was admitted for a left upper abdominal mass. She showed neither hormonal symptoms nor abnormal serum hormone levels. Ultrasound imaging showed that a heterogeneously solid and partly calcified tumor was located in the retroperitoneal space. Computed tomography showed a hypervascular tumor with central degeneration. Open laparotomy revealed that the tumor originated from the pancreas; it was removed in a mass including the spleen and the pancreatic body and tail. The resected specimen demonstrated that the 580-g tumor was multi-lobulated, encapsulated, and 14 × 14 × 7cm in size. Microscopically, the tumor consisted of cuboidal cells with round nuclei; the cells formed palisade and trabecular structures. Immunohistologically, chromogranin A, neuronspecific enolase, and glucagon were positive only for the tumor cells. Final diagnosis was endocrine tumor of the pancreas immunohistochemically producing glucagon. No tumor recurrence has been found 3 years after the surgery. We conclude that huge tumors in the retroperitoneal space must be differentiated from nonfunctioning endocrine tumors of the pancreas because the clinical course is markedly different.     

Aneurysmal subarachnoid hemorrhage in a patient with Wegener’s granulomatosis

A 34-year-old Japanese man admitted to hospital with pneumonia had previously undergone surgery for paranasal sinusitis and also for the clipping of an aneurysm at the origin of the anterior choroidal artery after subarachnoid hemorrhage. Laboratory tests performed at the present admission showed renal insufficiency and serological findings of raised proteinase 3 antineutrophil cytoplasmic antibody level. A renal biopsy was performed that showed diffuse necrotizing glomerulonephritis with fibrocellular crescents. The diagnosis of Wegeners granulomatosis(WG) was confirmed on the basis of the clinical picture, laboratory findings, and biopsies of renal tissues. The disease responded to prednisolone and cyclophosphamide. The association of WG with a ruptured intracranial aneurysm is rare and has not previously been confirmed.     

Retroperitoneal mucinous cystadenoma: report of two cases and review of the literature

Primary retroperitoneal cystic tumor is extremely rare, and its histogenesis and biological behavior remain speculative. Two surgical cases of retroperitoneal mucinous cystadenoma (Case 1, an 18-year-old woman; and Case 2, an 85-year-old woman) are reported. The cystadenomas in these cases were mainly lined by a monolayer of columnar or thin flat cells. Case 1 was positive for mucin and epithelial membrane antigen, whereas Case 2 was positive for a mesothelial marker (calretinin). Ciliated epithelium was also interspersed in Case 2. Some parts showed papillary projections, resembling well-differentiated papillary mesothelioma. Within the cyst walls of both cases, ovarian-like stroma that was positive for both estrogen and progesterone receptors was found. Interestingly, focal nodular hyperplasia of the liver was also detected in Case 1. We believe the retroperitoneal mucinous cystadenoma might have arisen from the peritoneum via mucinous epithelial metaplasia with a phenotype of extragenital Mullerian system.     

Receptor for advanced glycation end-products is a marker of type I lung alveolar cells

Lung alveolar epithelial cells are comprised of type I (ATI) and type II (ATII) cells. ATI cells are polarized, although they have very flat morphology. The identification of marker proteins for apical and basolateral membranes of ATI cells is important to investigate into the differentiation of ATI cells. In this paper, we characterized receptor for advanced glycation end-products (RAGE) as a marker for ATI cells. RAGE was localized on basolateral membranes of ATI cells in the immunoelectron microscopy and its expression was enhanced in a parallel manner to the differentiation of ATI cells in vivo and in primary cultures of ATII cells. RAGE and T1 alpha, a well-known ATI marker protein, were targeted to basolateral and apical membranes, respectively, when expressed in polarized Madine Darby canine kidney cells. Moreover, RAGE was expressed in ATI cells after T1 alpha in vivo and in ex in vivo organ cultures. In conclusion, RAGE is a marker for basolateral membranes of well-differentiated ATI cells. ATI cells require some signal provided by the in vivo environment to express RAGE.     

Taste function in elderly patients with unilateral middle ear disease

OBJECTIVE: It is generally said that taste function deteriorates naturally with age. Taste function after middle ear surgery in elderly patients has not been clarified. MATERIAL AND METHODS: The taste function of the chorda tympani nerve on the normal and diseased sides was examined before and after middle ear surgery using electrogustometry in 79 patients aged>60 years, and the findings were compared with those in 228 young and middle-aged patients. RESULTS: The threshold of electrogustometry on the normal side increased significantly with increasing age (p<0.0001). The rate of thresholds that were off the scale was highest in the>70 years age group. The preoperative threshold on the diseased side increased significantly with increasing age in patients with chronic otitis media (p=0.0029) and cholesteatoma (p<0.0001). In patients with chronic otitis media, the postoperative threshold of the>60 years age group tended to be higher than that of the<60 years age group. CONCLUSIONS: These findings suggest that the taste function of the chorda tympani nerve deteriorated on the diseased side as much as on the normal side in elderly patients. Therefore, in most cases, we do not have to pay as much attention to the chorda tymapani nerve when performing surgery in elderly patients compared to young and middle-aged patients.     

A head-mounted visual stimulator for neurotological examination

OBJECTIVES: Presently, the neurotological tests, using visual stimulation, such as optokinetic nystagmus test (OKN), eye-tracking test (ETT) is being widely used for the diagnosis of vertigo or disequilibrium. The problems of these tests are the large size of the visual stimulator and therefore a wide space requirement. Even if a small apparatus is developed, the apparatus itself would be very expensive. In this study, we developed a small visual stimulation test system comprising the virtual visor, which receives an image for visual stimulation from an on-line computer. METHODS: Using smooth pursuit and optokinetic stimulation onto a virtual visor we assessed the ENG recording in 20 normal subjects. RESULT: We found the 30 degrees /s OKN, horizontal eye tracking were adequately stimulated by this technique with reliable results. CONCLUSION: This new method of smooth pursuit and optokinetic stimulating by a virtual visor is capable of producing reliable results and may be used in the clinical laboratory of vertigo. However, this stimulator also has some limitations, mainly because of the visual angle of the virtual visor stimulator.