Disseminated abnormalities of cardiovascular autonomic functions in multiple sclerosis.

To determine whether patients with MS had abnormalities of autonomic cardiovascular functions, we evaluated 22 MS patients and 20 control subjects with a battery of six standardized tests. The two groups differed on three tests: heart rate and blood pressure responses to standing, and the cold-face test. One-half of the MS patients had abnormalities on two or more tests, but individual patients showed diverse abnormality patterns. Abnormalities of neural cardiovascular regulation are frequent in MS patients and show a heterogeneous pattern, consistent with scattered plaques.

Autonomic-cardiovascular dysfunction accompanies sensory-motor impairment during acrylamide intoxication.

We investigated the effects of acrylamide monomer on autonomic-cardiovascular functions and simple sensory-motor behaviors. Rats were intoxicated by ip injections of acrylamide at a dose of 50 mg/kg/day for 10 days; control animals received an equivalent volume of saline. Heart rate (HR) and systolic arterial blood pressure (BP) were measured using the method of indirect tail plethysmography. Intoxicated animals showed fluctuating but significant increases in HR and BP after the first dose of acrylamide, during the course of the intoxication, and two days after the last dose. Deficits in sensory-motor behaviors appeared after the first dose of acrylamide and progressed steadily throughout the exposure period, remaining two days after the last dose. More complex sensory-motor behaviors were affected earliest; hindlimb functions were affected before forelimb functions, characteristic of dying-back axonopathy. These results demonstrate that acrylamide alters common measures of autonomic-cardiovascular functioning in addition to simple sensory-motor behaviors.

MR imaging and MR angiography in the diagnosis of dural arteriovenous fistulas.

Intracranial DAVFs are most commonly found in the cavernous, transverse, and sigmoid sinuses. MR imaging and MR angiography can be used to screen for these lesions and determine if there is cortical venous drainage. Conventional angiography still has a major role in screening and is mandatory prior to any therapy. Spinal DAVFs are uncommon lesions seen predominantly in older men. The diagnosis can be suspected with MR imaging if a large draining vein is seen in association with swelling and enhancement of the conus and increased signal on T2-weighted images. MR angiography shows some promise in identifying the vascular anatomy of these lesions.

Sarcoidosis of the liver: evaluation with multiple imaging modalities.

Although sarcoidosis of the liver is common pathologically, imaging findings are extremely rare, because the noncaseating granulomas are usually not macroscopic and thus do not produce focal abnormalities. We present 2 cases of liver sarcoidosis with focal findings on computed tomography, magnetic resonance imaging, nuclear scanning, and ultrasonography. Imaging characteristics, which may facilitate making the diagnosis, are presented.

Advanced imaging techniques of the brachial plexus.

The brachial plexus is a complex structure that arises from nerve roots in the neck and terminates by dividing into peripheral nerves in the axilla. Imaging the brachial plexus can be difficult because of this anatomy. MRI now is the imaging modality of choice in the evaluation of brachial plexopathy. T1-weighted axial and oblique coronal images supplemented by T-2 weighted or STIR images are a standard protocol. MRI can be used to diagnose nerve root avulsion, neuromas, tumor, and radiation fibrosis.

Does pyruvate prevent acrylamide neurotoxicity? Implications for disease pathogenesis.

We used the prototype environmental neurotoxin, acrylamide monomer, to evaluate the hypothesis that neurotoxin-induced nerve fiber degeneration results from inactivation of axonal glycolytic enzymes. Treating intoxicated rats with sodium pyruvate, we hypothesized, would bypass the putative neurotoxin-induced blockade in glycolysis, thus ameliorating neurobehavioral and morphologic measures of neurotoxicity. After establishing that pyruvate itself did not affect behavior, we examined its effects on acrylamide-intoxicated animals. Pyruvate treatment had a significant effect on only one of eight neurobehavioral measures, though others showed similar trends. A morphologic observation of lumbar dorsal root ganglion cell bodies and peripheral nerves failed to show an effect of pyruvate. Those results suggested that inactivation of glycolytic enzymes alone is not a sufficient explanation of pathogenesis.