Migraine headaches have a complex pathophysiology; both vascular and neuronal mechanisms have been proposed. One possible scenario begins with brain-initiated events evolving to cortical spreading depression (CSD), which in turn activates the trigeminal nerve to cause headaches. Experimental evidence supports a relationship between CSD as a cause of migraine aura as well as CSD as a cause of trigeminal activation.
View Article and Find Full Text PDFObject: The Photon Radiosurgery System (PRS) is a miniature x-ray generator that can stereotactically irradiate intracranial tumors by using low-energy photons. Treatment with the PRS typically occurs in conjunction with stereotactic biopsy, thereby providing diagnosis and treatment in one procedure. The authors review the treatment of patients with brain metastases with the aid of the PRS and discuss the indications, advantages, and limitations of this technique.
View Article and Find Full Text PDFStereotact Funct Neurosurg
January 1999
The authors describe the case of a 36-year-old man who presented with bitemporal hemianopsia and a serum prolactin concentration of 1440 ng/ml. Magnetic resonance imaging of the pituitary revealed a presumed macroadenoma with suprasellar and temporal lobe extension. Although the patient's prolactin level was lowered to 55 ng/ml by bromocriptine therapy, no tumor shrinkage occurred.
View Article and Find Full Text PDFJ Neurosurg
January 1999
The authors present the case of a patient in whom intradural metastasis from renal cell carcinoma spread to the cauda equina. To the authors' knowledge, this is only the second report of its kind. This male patient had undergone nephrectomy for the treatment of renal cell carcinoma for 5 years and was diagnosed as having metastatic lung disease 1 year prior to admission.
View Article and Find Full Text PDFBackground: Untreated Cushing disease historically has a high mortality rate, but the long-term survival of patients with Cushing disease after transsphenoidal surgery has not been reported.
Objective: To determine long-term mortality rate in patients who are treated for Cushing disease with current management techniques.
Design: Retrospective case series.
J Clin Endocrinol Metab
October 1998
To analyze the long term outcome after multimodality therapy for acromegaly, a retrospective review was performed on 162 patients who underwent transsphenoidal surgery at Massachusetts General Hospital between 1978 and 1996. The surgical cure rate for microadenomas was 91%, that for macroadenomas was 48%, and it was 57% overall. The surgical cure rate was significantly dependent on tumor size, but was not dependent on age or sex.
View Article and Find Full Text PDFIntroduction: A mobile computed tomographic scanner has been developed in which the scan plane is selected by means of gantry translation, rather than by translation of the patient table. This permits computed tomographic scanning in situ of any patient who is positioned on a radiolucent surface that fits within the inner diameter of the gantry. We report the design of and initial experience with this scanner as used with adapters for intraoperative and bedside computed tomography (CT).
View Article and Find Full Text PDFActa Neuropathol
March 1998
Fas ligand (FasL) is involved in tumor evasion from the immune system. We analyzed 22 human gliomas for expression of FasL and its receptor, Fas. Positive FasL and Fas immunoreactivity was detected in 13 out of 22 tumors by Western blotting and in 15 out of 22 tumors by immunohistochemistry.
View Article and Find Full Text PDFThe majority of cases of Cushing's disease are due to an underlying pituitary corticotroph microadenoma (< or = 10 mm). Corticotroph macroadenomas (> 10 mm) are a less common cause of Cushing's disease, and little is known about specific clinical and biochemical findings in such patients. To define further the clinical characteristics of patients with corticotroph macroadenomas, we performed a retrospective review of Cushing's disease due to macroadenomas seen at Massachusetts General Hospital between 1979 and 1995.
View Article and Find Full Text PDFThis report offers a description of typical changes seen on gadolinium-enhanced magnetic resonance (MR) imaging of the entire spine that indicate spontaneous intracranial hypotension (SIH). To the authors' knowledge, this is the first report of its kind. They describe three cases of SIH that were accompanied by dural enhancement throughout the neuraxis on imaging, with the evolution of associated subdural and epidural fluid collections in the spine.
View Article and Find Full Text PDFAlthough phorbol esters, synthetic activators of protein kinase C (PKC), can stimulate large increases in the binding of cytosolic PKC to form membrane-bound PKC (PKCm, an indicator of PKC activation), the authors report that even small increases in PKCm induced by phorbol esters (8-12% of total PKC content) can be associated with significant PKC-mediated contractions in vitro (50-85% of maximum) in normal canine cerebral arteries. Increases in PKCm of similarly small magnitude were found in vitro when control artery segments were exposed to hemolysate, but only if the arterial smooth-muscle cells were first slightly depolarized by increased extracellular potassium to values of membrane potential similar to those observed in canine cerebral arteries during chronic cerebral vasospasm. These increases in PKCm (6-8% of total PKC content) coincided with a greatly augmented contractile response to hemolysate.
View Article and Find Full Text PDFObjective: This report describes the clinical evaluation of a novel stereotactic radiosurgical device for interstitial irradiation of malignant brain tumors.
Methods: Fourteen patients with cerebral lesions less than 3.5 cm in greatest diameter were treated with a single fraction of stereotactic interstitial irradiation (average, 12.
Objective: We report the design and initial characterization of the dosimetry and radiobiology of a novel device for interstitial stereotactic radiosurgery.
Instrumentation: The device is lightweight, handheld, and battery-powered, and it emits x-ray radiation from the tip of a probe 3 mm in diameter by 10 cm in length.
Methods: The dosimetry was characterized by two independent methods: thermoluminescent dosimeters and radiochromic film.
Objective: To evaluate the safety and any potential effect of cyclosporine A (CycA) in preventing cerebral vasospasm.
Methods: Nine patients with Fisher Grade 3 subarachnoid hemorrhages were studied. After a loading dose of 7.
Over the last 30 years, perfluorocarbons (PFCs) have been extensively investigated as oxygen carriers. Early studies indicated that these compounds could be used as blood substitutes or protective agents against ischemia. Adverse characteristics such as instability, short intravascular half-life, and uncertainties concerning possible toxicity precluded wide clinical application.
View Article and Find Full Text PDFThe techniques of two experimental surgical operations on the trigeminal nerve are described, namely, excision of the trigeminal ganglion (ganglionectomy) and division of the trigeminal root (rhizotomy), in the cat. These techniques have been developed with the specific aims of achieving the trigeminal lesion and also preserving a satisfactory postoperative quality of life for the animal in order to make it possible to study the long-term effects of trigeminal dennervation. To the best of our knowledge, a detailed description of such a surgical methodology is lacking; reporting of these procedures may facilitate future research on the trigeminal nerve.
View Article and Find Full Text PDFIt remains unknown what proportion of delayed arterial narrowing after subarachnoid hemorrhage depends on ongoing metabolic activity within arterial smooth muscle cells versus changes in the passive structural properties of the arterial wall. To determine this, vasospasm was induced by the double subarachnoid hemorrhage model. Anterior spinal artery segments were harvested from control dogs and from dogs with vasospasm.
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