Hugo V. Rizzoli

Absence of autoregulation in peripheral nerve blood flow

Blood flow was measured in the sciatic nerve of cats utilizing the method of hydrogen polarography. The mean baseline blood flow for all animals was found to be 47.1 ml/100 g/min +/- 14.9 SD. The flow changes produced by lowering the blood pressure by exsanguination and elevation by the use of angiotensin were then evaluated. The highest (normal) levels of blood flow were observed between the mean blood pressures of 80-110 mm Hg. At mean systemic arterial pressures of less than 85, there was a marked decrease in peripheral nerve blood flow with no detectable flow being measured below mean systemic pressures of 50 mm Hg. Above 105 mm Hg mean arterial pressure, there was a very gradual and progressive decline in blood flow to the levels measured at 200 mm Hg. These findings indicate a complete absence of vascular autoregulation in the peripheral nerve trunks.

Soluble membrane antigens of brain tumors. I. Controlled testing for cell-mediated immune responses in a long surviving glioblastoma multiforme patient

A patient with glioblastoma multiforme survived 18 years after diagnosis and underwent 20 operations for extracranial metastasis. An immunologic survey of the patient was made over a 1‐year‐period using in vitro tests of lymphocyte responsiveness and skin tests with control and tumor antigens isolated from autologous and allogenic brain cell membranes. Two tissue‐associated soluble cell membrane antigens also present in normal white matter, and two tumorassociated antigens (TAA) produce cell‐mediated immune responses in patients with brain tumors. One of these tumor‐associated antigens predominates in meningioma cells. In addition some low molecular weight components appeared, which seemed to be unique for the glioblastoma cells from the longsurviving patient. Cancer 40:660–666, 1977.

Localized isolated angiitis of the central nervous system associated with primary intracerebral lymphoma

Isolated angiitis of the central nervous system (IACNS) is a form of granulomatous vasculitis that is confined to the nervous system. A patient with localized IACNS affecting the left internal carotid and posterior cerebral artery adjacent to a primary intracerebral lymphoma of the midbrain along with associated granulomatous inflammation of the dura, leptomeninges, and ependyma of the aqueduct of Sylvius is described. His course was complicated by many neurologic complications before his death. Prednisone and cyclophosphamide were unable to control his disease. More aggressive therapy may be indicated for patients with lymphoproliferative lesions and associated central nervous system (CNS) vasculitis who fail to respond to conventional therapy.

Blood flow in peripheral nerves: Normal and post severance flow rates

Regional blood flow has been measured in the sciatic nerve of cats utilizing the method of hydrogen polarography. The mean baseline flow of the sciatic nerve in cats was found to be 43 ml/100 g/min +/- 1.6 SD. Flow rates were somewhat erratic in both the proximal and distal segments of the nerve following nerve severance. The erratic flows were observed over the first 30 min following nerve cutting and by 1 hr had essentially stabilized at approximately the pre-severance flow level.

Psammoma bodies in meningioma

Psammoma bodies from eight meningiomas have been examined by both light and scanning electron microscopy (SEM). The bodies are primarily composed of calcium apatite which is deposited within a nidus of tightly laminated collagen fibers.

The effect of sciatic nerve stimulation on spinal cord blood flow

Focal spinal cord blood flow was measured in the left dorsal column during left sciatic nerve stimulation, and compared to blood flow in the same area during sciatic nerve inactivity. Blood flow was found to be significantly increased during stimulation. It is suggested that this increased blood flow is a reflection of increased metabolic demands of the neurons and synaptic systems within the internuncial neural pools, activated by stimulation of all components of the sciatic nerve, rather than a reflection of increased non-synaptic axonal conduction in the dorsal column.

A method for estimating edema in experimental traumatic spinal cord injury

Abstract In this experiment a method was developed to estimate spinal cord edema following experimental trauma. After the intravenous administration of Evans Blue solution and 100 μc of iodinated I-131 serum albumin, the spinal cords of rhesus monkeys were traumatized with a 600 g cm injury. Edema at the injury site was evaluated at 6 hr after injury and compared to a section of uninjured spinal cord from each animal. The I-131 serum albumin acted as an excellent marker to estimate the extravasation of serum proteins into the neural extracellular spaces. In the future this method will be used to test the effect of various drugs on post-traumatic edema formation.