The involvement of increased brain tissue CO2 tension in acetazolamide-induced brain acidosis was investigated by comparing the brain pH response to acetazolamide with that to hypercapnia. CO2 and pH sensors were placed bilaterally into cerebral white matter to 15 mm depth in cats. Group I cats (n = 9) breathed spontaneously, and in situ brain tissue PCO2 and pH (PbCO2 and pHb) were measured after intravenous acetazolamide administration (20 mg/kg). Group 2 cats (n = 9) were paralyzed and ventilated mechanically, and the changes of pHb were investigated by adjusting the ventilation to maintain the same Pbco2 values as in the acetazolamide-treated group. Pbco2 changes were not significantly different between the two groups. However, pHb responses were quite different: the fall in pHb was progressive in Group 1 but transient in Group 2. Brain acidosis after acetazolamide administration is not due to the rise in brain tissue CO2 tension.
A new method was designed to investigate and evaluate the biological effectiveness of hyperthermia combined with continuous low-dose-rate irradiation (CLDRI) from encapsulated iridium-192 seed sources on glioma cells in vitro using the MTT assay. The system consists of 10 iridium seeds contained in a catheter bent into a circle, which is placed on a culture plate containing the cells. The effects of CLDRI and CLDRI combined with hyperthermia on a cultured rat glioma cell line (C-6) were studied. The number of surviving cells decreased as the total radiation dose increased. There was no significant difference in survival rates at dose rates of 0.1 Gy/hr and of 0.2 Gy/hr (p = 0.2811). An additive effect was observed in the cells treated with hyperthermia at 41°C and 42°C, combined with CLDRI, and a synergistic effect between the two treatment modalities was observed at 43°C. This new device is less expensive, easily reproducible, and can also be performed easily enough to examine a large number of samples in a short time period for sensitivity testing.
A conjugate of manganese-metalloporphyrin and gadolinium (Gd)-diethylenetriaminepenta-acetic acid (Gd-ATN10) was developed as a tumor-specific enhancement agent for magnetic resonance (MR) imaging. Gd-ATN10 was evaluated in an experimental 9L gliosarcoma rat tumor model. T1-weighted MR imaging showed enhancement of the tumor which persisted for up to 24 hours. Gd concentration measurement by inductively coupled plasma atomic emission spectroscopy revealed the peak Gd concentration was reached after 30 minutes and Gd was retained in the blood and tumor up to 24 hours. There was no uptake of Gd in the normal brain and little in the skin. Gd-porphyrin derivatives are potentially useful agents for tumor diagnosis on MR imaging and for neutron capture therapy.
A 4-year-old boy suffered a transorbital penetrating head injury caused by falling on a wooden chopstick while walking. The chopstick was removed completely, but full diagnosis was delayed for 3 years because the entry wound had not appeared to be serious. The patient later experienced rhinorrhea of cerebrospinal fluid (CSF), and recurrent bacterial meningitis. Surgical repair of the CSF fistula at the anterior skull base was performed when the patient was 7 years old. Previous penetrating head injury should be considered in patients with recurrent CSF fistula and meningitis.
A 67-year-old male presented with sudden onset of aphasia and right hemiparesis on January 27, 1995. latrogenic dissection of the left internal carotid artery occurred during attempted local thrombolytic therapy for embolic occlusion of the middle cerebral artery. His neurological condition worsened. Following an unsuccessful angioplasty for the dissection, a Palmaz-Schatz stent was deployed over the dissection. Local thrombolytic therapy was then successfully completed. Anticoagulation and antiplatelet medications were given to prevent further embolic stroke. Follow-up angiography at 2 weeks and 8 months showed good patency of the stented segment. He has experienced no cerebral ischemic events since the treatment.
A 32-year-old female presented with a dural arteriovenous fistula in the transverse-sigmoid sinus caused by stenosis of the left internal jugular vein. The feeding arteries were embolized, resulting in nearly complete disappearance of the fistula. This case supports the idea that dural arteriovenous fistula is an acquired lesion caused by intravenous hypertension.
A 25-year-old female patient presented with hemorrhage from a cerebellar cavernous malformation manifesting as headache and vomiting. She died of massive rebleeding within 1 week of the previous hemorrhage. The natural history of cavernous malformations was considered relatively benign, with significant hemorrhage being uncommon. The present case suggests that emergency surgery should be performed for patients with unstable clinical conditions and/or those with a significant mass effect in the cerebellum or the brainstem.
A neonate male who developed cavernous angioma was born with a severe intraventricular hemorrhage and intraparenchymal hemorrhage in the basal ganglia. Magnetic resonance imaging revealed a large, non-enhanced hematoma that packed the lateral ventricle. Surgery on the 2nd day of life verified a cavernous angioma associated with minimal hemosiderin and gliosis. Fetal cavernous angiomas, unlike such malformations in other age groups, can present with a devastating hemorrhage because of the lack of gliosis in the surrounding brain.
A 36-year-old male presented with a very rare epidermoid tumor in the sphenoid sinus manifesting as paresis of the right sixth cranial nerve and diplopia. Computed tomography and magnetic resonance imaging revealed a mass lesion in the sphenoid sinus expanding to the clivus. The cystic tumor, which contained cholesterin crystals, was extensively removed via the transsphenoidal approach. Histological examination showed epidermoid cell layers, consistent with the diagnosis of epidermoid tumor. Epidermoid tumors should be considered in the differential diagnosis of lesions in the sphenoid sinus.
A 56-year-old male was admitted in January 1994, with back pain persisting for 2 months. Magnetic resonance imaging disclosed a homogeneously enhanced mass occupying the spinal canal at the T-8 level and extending into the retropleural space through the left intervertebral foramen between T-8 and T-9. The diagnosis was a thoracic dumbbell-shaped neurinoma. The tumor was successfully removed through a posterolateral approach using hemilaminectomy and partial costotransversectomy with preservation of ipsilateral joint facets. Histological examination indicated neurinoma. This approach allows excellent visualization of anterior paraspinal components of the tumor, preserves important anatomic structures, and requires minimal compression of the cord for removal of the lesion.