Evidence of cellular supplies to the endolymphatic sac from the systemic circulation.

Donor T lymphocytes injected into the host systemic circulation were observed to infiltrate into the host endolymphatic sac in mice. These findings suggest that the endolymphatic sac, a major immune organ in the inner ear, is supplied with immunocompetent cells from the systemic circulation. This concept is consistent with clinical reports that inner ear disorders accompany certain systemic autoimmune diseases. Bone marrow transplantation to replace autoreactive immunocompetent cells with normal cells should be considered as a potential therapy for inner ear autoimmune diseases and an alternative to conventional treatments.

Glycerol effect on the guinea pig tectorial membrane.

The tectorial membrane (Tm) of guinea pigs has been found to have an altered organization of its matrix fibers in response to intravenously administered glycerol. Following treatment, the Tm middle zone shows an increase in waviness and clumping of fibers in non-hydropic and several hydropic ears in contrast to non-treated control ears. Residue of the internal sulcus cells occasionally fills the subtectorial space. In the present study, additional investigations were performed with scanning electron microscopy in order to study the relationship between the Tm and the organ of Corti, as well as the relationship between Hensen's stripe and the inner hair cell. Present findings provide evidence for a connection between the inner hair cell stereocilia and Hensen's stripe which may be the molecular basis for the modulation of hearing during the glycerol test in a patient with Meniere's disease.

Thyroid follicle transplantation by percutaneous injection.

We previously reported on the isolation of thyroid follicles from thyroid tissue and their acceptance after allogeneic transplantation under the renal capsule with laparotomy in mice. In the present study, we introduced a new method of autologous transplantation of thyroid follicles accepted in the hosts after percutaneous injection into the spleen or into fat tissue in the peritoneal cavity without laparotomy in rats. This method of thyroid transplantation by a single injection, which induces little stress in the host, is applicable to autologous and allogeneic transplantations and may release patients from the burden of daily life-long administration of thyroxine.

Effects of acetazolamide on acid-base balance in the endolymphatic sac of the guinea pig.

The effects of acetazolamide, a carbonic anhydrase inhibitor, on acid-base parameters in the endolymphatic sac of the guinea pig were investigated using ion-selective microelectrodes. Bicarbonate concentration was reduced and pH shifted to being acidic immediately after administration of acetazolamide. Chloride concentration in the endolymphatic sac increased after carbonic anhydrase inhibition. These findings provide evidence of an active function of carbonic anhydrase in the endolymphatic sac and suggest that carbonic anhydrase activity is involved in the formation of endolymphatic sac fluid.

Experimental interruption of the endolymphatic duct and its effect on the DC potential in the endolymphatic sac.

The endolymphatic sac (ES) of the guinea pig was isolated from the remainder of the inner ear by means of surgical interruption of the endolymphatic duct (ED). The DC potential in the ES lumen and the morphology of the ES were studied using glass micro-electrodes and a light microscope at various time intervals after the interruption of ED. The DC potential did not significantly change 1 h postoperatively, compared to findings in the non-operated ear, but a significant decrease of the DC potential was observed after 1, 3 and 7 days postoperatively. A histologically-stainable substance in the ES lumen was enhanced on the operated side. The isolated ES shows a disturbance of mechanism(s) maintaining the DC potential and there is a secretion of a stainable substance into its lumen.

Acidity in the endolymphatic sac fluid of guinea pigs.

The pH value and the DC potential in the endolymphatic sac (ES) were measured using H(+)-selective double-barreled electrodes and the intra- and extradural approach, the pH value in the ES fluid (6.65 +/- 0.12, n = 7) was markedly lower than that in the cerebrospinal fluid (7.39 +/- 0.07, n = 7). Acidity in the ES fluid, under normal (nontreated) conditions may be closely associated with metabolism in the epithelium of the ES.

Positive and negative DC potential in the vestibular system of pigeons.

DC potential in the ampulla of pigeons was studied using a glass microelectrode. After the extirpation of the cochlear duct no change in the DC potential was found. A reduction of the negative DC potential due to anoxia (anoxia-sensitive negative potential, ASNP) was found in the ethacrynic acid (EA)-intoxicated ear, while this finding was minimal or absent in the ouabain-intoxicated ear. The perilymphatic perfusion with K(+)-substituted Ringer's solution resulted in a rapid reduction of the negativity due to EA or ouabain. These findings indicate that the positive DC potential in the ampulla seems to be produced by itself and K+ diffusion potential is the main source of negative DC potential. ASNP may be the unique potential in the EA-intoxicated ear in warm-blooded animals.

[A case of spontaneous spinal epidural hematoma presenting Brown-Séquard syndrome].

Although there have been a few reports of spontaneous spinal epidural hematoma, it may be difficult to make a correct diagnosis of the lesion because of atypical clinical symptoms. The authors reported a case of spontaneous spinal epidural hematoma presenting Brown-Séquard syndrome, with a review of literature. This 75-year-old male experienced a sudden onset of severe dorsal neck pain during sleep associated with right hemiparesis which deteriorated quickly to hemiplegia, without loss of consciousness, nausea, vomiting and vertigo. The patient has a history of hypertension and has been treated for chronic hepatitis for one year. On admission, neurological examination revealed right hemiplegia with normotensive deep tendon reflexes, and loss of pain and temperature sensations below the level of C5 on his left side. Position sense of fingers and toes was diminished on his right side, and hyperesthesia was recognized at the area of C4 level. Consciousness disturbance, cranial nerve signs, and urinary incontinence were not seen. Right retrograde vertebral angiograms showed no abnormal vascular shadow, even though anterior spinal artery was visible at the level of C8 through C5. Cervical CT scan revealed a left-side dominant extradural high density mass which situated dorsally at around the upper part of C2 body changing it's position to dorsolaterally as it descended to the lower part of C5. On contrast enhancement study, only the margin of the lesion was partially enhanced, which might be the hematoma membrane. On the third day after the onset, laminectomy from C2 to C5 was performed and the epidural hematoma was evacuated.(ABSTRACT TRUNCATED AT 250 WORDS)

Total removal of a parasagittal meningioma of the posterior third of the sagittal sinus and its repair by autogenous vein graft. Case report.

Total removal is reported of a parasaggital meningioma that invaded the lateral wall and lateral recess of the posterior third of the superior sagittal sinus. The operation was performed by using a silicone rubber non-collapsible tube with an inflatable balloon cuff at each end for the bypass of the sinus blood, and entailed repair of the defect in the sinus wall by a saphenous vein graft. The clinical results and angiographic findings are presented.