Cerebral vasoconstriction in toxemia.

Three patients with toxemia developed acute neurologic deterioration postpartum. In all, cerebral angiography revealed widespread arterial vasoconstriction. Cerebral vasoconstriction may be an important cause of neurologic complications in toxemia.

Elevated plasma glucagon in amyotrophic lateral sclerosis.

This study shown an abnormality in glucagon levels that may explain the glucose intolerance, abnormal insulin reactions, and abnormal plasma amino acid levels seen in amyotrophic lateral sclerosis (ALS). We randomly administered two test meals, differing only in protein source (soy versus casein) at least 1 week apart and measured fasting and postprandial bloods for glucagon, insulin, and glucose levels in 11 ALS patients. With the soy test meal, glucagon levels were elevated in all ALS patients compared with controls: at fasting (237 +/- 111 versus 108 +/- 46 pg/ml, p less than 0.01) and 1/2 hour (389 +/- 94 versus 133 +/- 68 pg/ml, p less than 0.001), and 2 hours postprandial (379 +/- 75 versus 108 +/- 53 pg/ml, p less than 0.001). Glucagon levels after the casein test meal were also significantly elevated. Insulin was elevated by both test meals. Casein produced significant glucose intolerance.

Coaptation of the anterior rami of C-3 and C-4 to the upper trunk of the brachial plexus for cervical nerve root avulsion.

No surgical procedure has been available to repair cervical nerve root avulsion inside the spinal canal. Results with peripheral neurotization of denervated muscles have been discouraging. The authors have performed bridge-graft coaptation in three patients with C-5 and C-6 nerve root avulsion. The components of the coaptation included the anterior primary rami of C-3 and C-4 as the donor material, the entire upper trunk as the recipient, and the sural nerve graft as the bridge. This procedure resulted in restoration of motor function in the biceps and shoulder-girdle muscles and produced improved sensation. Stimulation of the C-3 and C-4 nerve roots elicited electrical responses in the biceps and deltoid muscles that indicated nerve growth through the graft and the brachial plexus into these muscles. This reconstructive procedure is effective and should stimulate development of new approaches to treatment of cervical nerve root avulsion and proximal brachial plexopathy.

EEG frequency patterns in the cat prepyriform cortex during sleep and waking.

The cellular populations in the prepyriform cortex are a primary processing station for sensory information from the olfactory bulb. These populations are also influenced from forebrain and other brain systems involved in behaviour. Recording electrodes can be precisely placed in this cortex compared to many other brain structures. This permits straddling the cortical superficial pyramidal cell layer with a bipolar recording configuration and the ability to obtain information about awake-vigilant and other state conditions from this brain structure. Methadone, a vigorously arousing drug in the cat, and a short acting barbiturate was administered to compare the differences of EEG patterns obtained during normal awake and sleep conditions. Fourier analysis was used in this study and combined with computer profiles of spectra to show time relationships of the state conditions in the cortex. Good separation of the spectra, between the major states in the cat, were observed using this technique for both natural and drug-induced changes.

Newer electrodiagnostic techniques in peripheral nerve injuries.

Careful attention to technique is essential for the accurate evaluation of peripheral nerve function using conventional EMG and nerve conduction studies. Numerous technical, anatomic, and physiologic pitfalls must be avoided. The amplitudes of the M wave and SNAP contain useful diagnostic information and should be evaluated carefully in addition to conduction velocity and distal latency. Newer techniques using the F wave, H reflex, SEP, dermatomal SEP, and quantitative EMG may be helpful in evaluation of selected peripheral nerve problems. Comparative nerve conduction studies using "inching" technique permit evaluation of short nerve segments. Comparisons with parallel nerves improve diagnostic sensitivity.

Amyotrophic lateral sclerosis and occupational exposure to electromagnetic fields.

In an hypothesis-generating case-control study of amyotrophic lateral sclerosis, lifetime occupational histories were obtained. The patients (n = 28) were clinic based. The occupational exposure of interest in this report is electromagnetic fields (EMFs). This is the first and so far the only exposure analyzed in this study. Occupational exposure up to 2 years prior to estimated disease symptom onset was used for construction of exposure indices for cases. Controls (n = 32) were blood and nonblood relatives of cases. Occupational exposure for controls was through the same age as exposure for the corresponding cases. Twenty (71%) cases and 28 (88%) controls had at least 20 years of work experience covering the exposure period. The occupational history and task data were used to classify blindly each occupation for each subject as having high, medium/high, medium, medium/low, or low EMF exposure, based primarily on data from an earlier and unrelated study designed to obtain occupational EMF exposure information on workers in "electrical" and "nonelectrical" jobs. By using the length of time each subject spent in each occupation through the exposure period, two indices of exposure were constructed: total occupational exposure (E1) and average occupational exposure (E2). For cases and controls with at least 20 years of work experience, the odds ratio (OR) for exposure at the 75th percentile of the E1 case exposure data relative to minimum exposure was 7.5 (P < 0.02; 95% CI, 1.4-38.1) and the corresponding OR for E2 was 5.5 (P < 0.02; 95% CI, 1.3-22.5). For all cases and controls, the ORs were 2.5 (P < 0.1; 95% CI, 0.9-8.1) for E1 and 2.3 (P = 0.12; 95% CI, 0.8-6.6) for E2. This study should be considered an hypothesis-generating study. Larger studies, using incident cases and improved exposure assessment, should be undertaken.

Modulation of chemiluminescence in a murine macrophage cell line by neuroendocrine hormones.

This study determined the effects of neuropeptides and neuroendocrine hormones at the cellular level of the immune response using a murine macrophage cell line, J774, which exhibits a chemiluminescent oxidative burst upon acute stimulation with zymosan. We report that the zymosan-triggered oxidative burst of J774 cells can be modulated by the opioid peptides beta-endorphin (beta-END) and dynorphin A (DYN) in a naloxone-reversible fashion. Norepinephrine (NE) also modulated chemiluminescence (CL) emission of J774 cells, with dose-dependent suppression of CL dependent upon co-incubation with gamma-interferon (gamma-INF). Without gamma-INF co-incubation, NE shared with the opioid peptides beta-END and DYN the ability to modulate oxidative burst, producing an inverted-U dose response. These data indicate that J774 cells may be useful for explaining some mechanisms through which the neuroendocrine system interacts with the immune system.

Medial brachial fascial compartment syndrome: anatomic basis of neuropathy after transaxillary arteriography.

The authors reviewed their experience with 320 transaxillary arteriograms, as well as the English-language literature on neuropathy complicating transaxillary arteriography. Three of their patients had median and ulnar motor and sensory nerve injury, and six others had only sensory involvement. The occurrence or severity of nerve injury did not correlate well with the size or presence of an observable axillary or arm hematoma. Dissection of the axillae and arms of 25 human cadavers revealed a tough medial brachial fascial compartment (MBFC) outside a thin axillary sheath. The median and ulnar nerves were within the MBFC at an arterial puncture site just lateral to the anterior axillary fold. The radial and musculocutaneous nerves exited the MBFC more proximally. The different levels at which the major nerves of the brachial plexus exit the MBFC explain the anatomic distribution of the nerve injuries associated with compression by a hematoma after transaxillary arteriography.

CT and angiographic correlation of severe neurological disease in toxemia of pregnancy.

Two patients with severe cerebral symptoms of toxemia of pregnancy were examined using computed tomography (CT) and angiography. CT disclosed extensive areas of low attenuation within the cerebral hemispheres. Angiography revealed constriction and narrowing of proximal and peripheral vessels suggesting vasculitis with extensive areas of impaired regional cerebral blood flow. A review of the known pathology and the theories regarding the pathophysiology of the cerebral effects of toxemia is presented.

Effects of the interaction between ferric iron and L-dopa melanin on T1 and T2 relaxation times determined by magnetic resonance imaging.

T1 and T2 relaxation times of agar phantoms containing L-dopa melanin and Fe3+ were measured under MRI conditions. Fe3+ shortened T1 and T2 relaxation times. Melanin influenced relaxation times only in the presence of Fe3+; thus, contrast in MR images of the basal ganglia may depend upon levels of both paramagnetic iron and neuromelanin.