Intratemporal vascular tumors: detection with CT and MR imaging

The diagnostic contributions of computed tomography (CT) and magnetic resonance (MR) imaging were compared in 12 patients with benign intratemporal vascular tumors (hemangioma or vascular malformation). The tumors included six in the internal acoustic canal and six in the geniculate ganglion region. Clinical and histologic correlations were made. Two of the six patients with tumors in the internal acoustic canal underwent CT, and both required gas cisternography to show the tumor. Five patients in that group underwent MR imaging, and all five studies showed the tumor. All six patients with geniculate ganglion tumors underwent CT. Results in one study were questionable, and five showed the tumor. Five patients in this group underwent MR imaging, but the MR findings were positive in only two cases. MR imaging should therefore be performed before CT in the evaluation of facial nerve dysfunction, as it demonstrated all tumors in the internal acoustic canal and some in the geniculate ganglion region. If MR findings are negative, CT should then be performed to rule out a possible geniculate ganglion lesion.     

Differential modulation by dopamine of responses evoked by excitatory amino acids in human cortex.

The responses of human neocortical neurons to iontophoretic application of excitatory amino acids and their modulation by dopamine (DA) were studied in vitro. Brain slices were obtained from children undergoing surgery for intractable epilepsy. Application of N-methyl-D-aspartate (NMDA) to the slices induced slow depolarizations accompanied by decreased input conductances and sustained action potentials in cortical neurons. Glutamate produced rapid depolarizations and firing with few changes in input conductances. Quisqualate also induced depolarization and firing, but input conductances increased during the rising phase of the membrane depolarization. Iontophoretic application of DA alone produced no change in membrane potential or input conductance. However, when DA was applied in conjunction with the excitatory amino acids, it produced contrasting effects. With either bath application of DA or when iontophoresis of DA preceded application of NMDA, the amplitude of the membrane depolarizations and the number of action potentials were increased, whereas the latency of these responses decreased. In contrast, DA decreased the amplitude of the depolarizations and the number of action potentials evoked by glutamate or quisqualate. The fact that DA affects responses to NMDA and glutamate or quisqualate in opposite directions is of considerable importance to the understanding of cellular mechanisms of neuromodulation and the role of DA in cognitive processing and in epilepsy.     

Long-term follow-up and the role of surgery in adolescents with morbid obesity

PURPOSE: Obesity has become a health-care crisis in the United States. Adolescent obesity is now one of the most common childhood disorders, with 4.7 million American adolescents having a body mass index (BMI) greater than the 95th percentile. Most patients do not respond to diet modification or exercise programs and attention is now turning toward surgery as a source of weight loss in adolescents. Few studies have looked at the overall morbidity and mortality of weight loss surgery in this patient population. METHODS: This is a retrospective study of medical charts of 15 bariatric surgical procedures performed on 14 adolescents without known genetic syndromes associated with severe childhood obesity from 1971 to 2001 at the University of Minnesota. Procedures performed on these patients included vertical banded gastroplasty (n = 7), Roux-en-Y gastric bypass (n = 5), and jejunoileal bypass (n = 3). Jejunoileal bypass procedures were performed from 1971 to 1977, after which time this procedure was abandoned. Patient age ranged from 13 to 17 years (mean, 15.7 years). Mean follow-up time was 6 years, with 9 patients available for long-term follow-up. RESULTS: All procedures were performed using an open technique by 1 surgeon. There were no perioperative deaths; complications included 1 case of wound infection, 2 episodes of dumping syndrome that resolved without revision, 1 episode of hypoglycemia, and 1 case of short-term electrolyte imbalance in a patient who underwent jejunoileal bypass. The average BMI dropped from 58.5 +/- 13.7 to 32.1 +/- 9.7 kg/m(2) (P < .01)--a 45% reduction. CONCLUSIONS: Surgery for morbid obesity is safe and results in significant weight loss in adolescents who fail medical therapy.     

Ultrastructural alterations in caudate nucleus in aged cats

These studies provide information on the changes in the ultrastructure in the caudate nucleus of aged cats. The major findings was that there was a decrease in the density of synapses in caudate neuropil. This decrease occurred in animals after 3 years of age and remained relatively constant in older animals. In conjunction with this change a population of unusually long synapses also occurred. These larger synaptic appositions were associated with enlarged spine heads. The caudate also showed a number of qualitative ultrastructural alterations. Many neurons contained accumulations of lipofuscin or lipopigment granules in aged animals. These inclusions occurred in both soma and dendrites of neurons and all types of glial cells. A unique configuration of collapsed agranular cisterns also was observed in aged animals. The present results indicate that decreases in synaptic density may by one morphological event underlying functional alterations observed in caudate neurons in aged cats.     

Acute peripheral arterial and graft occlusion: treatment with selective infusion of urokinase and lysyl plasminogen

Thirty-five patients hospitalized for recent angiographically documented arterial occlusion in the legs (27 femoropopliteal arteries and eight grafts) benefited from local fibrinolytic therapy delivered at the site of the occlusion with a 4- or 5-F catheter. This therapy combined a continuous urokinase (UK) infusion of 1,000 U/kg/hour and a lysyl plasminogen (LYS-PLG) infusion of 15 microkatals every 30 minutes. Angiographically confirmed lysis was obtained in 85% of the cases. Only 3% of the patients had major and 6% had minor groin hematomas. Only two patients had concentrations of fibrinogen as low as 100 mg/dl. Intravascular infusion of UK-LYS-PLG is as effective as streptokinase. Its excellent tolerance makes it a good alternative in the treatment of acute ischemia in the lower limbs.     

Differences in the glucocorticoid to progesterone receptor selectivity of inhaled glucocorticoids.

Due to the high affinity of new inhaled corticosteroids (ICS) towards the glucocorticoid receptor (GR), and because of the similarities between the binding domains of the GR and the progesterone receptor (PR), the present study focused on assessing the relative binding affinities (RBA) of glucocorticoids (systemic and ICS) to PR (RBAPR). By comparison with the affinities towards the GR (RBAGR) the binding selectivities were also assessed. In general, the selectivity of the investigated glucocorticoids showed a decreasing trend with increasing lipophilicity. When orally administered, less lipophilic glucocorticoids showed the highest selectivity, with RBAGR/RBAPR ratios of 1,375, 760 and 476 for betamethasone, beclomethasone and dexamethasone, respectively. For ICS, mometasone furoate, the most lipophilic steroid, was the least selective (1.1), followed by beclomethasone monopropionate (9), fluticasone propionate (12), triamcinolone acetonide (18), mometasone (25) and budesonide (44), which shows the highest selectivity among inhaled glucocorticoids. In conclusion, the present study revealed that there are differences in selectivity among commercially available glucocorticoids. Future clinical studies are needed to investigate whether the high affinity of some of the investigated glucocorticoids to the progesterone receptor is of clinical relevance.     

What some patients can eat during migraine attacks: therapeutic and conceptual implications

Although nausea and vomiting are diagnostic migraine symptoms, most patients can take tablets by mouth and a few say they can eat some food. This study was conducted to determine the proportion who could eat or drink, what was consumable and with what effect. One-hundred-and-nine migraineurs were asked what they could eat or drink at the beginning or height of their attacks; 59 could not take any food by mouth, but 50 could eat during the headache phase of their migraine attacks. Four ate normally, 5 took smaller amounts of their normal dietary intake, and 3 took lighter meals. Dry, carbohydrate foods were consumable by the remaining 38: a few had specific cravings, most stated the precise variety which, when eaten, reduced nausea, headache, other symptoms or length of attacks. Patients should therefore be encouraged to eat what they can tolerate, with their tablets taken as early as possible after the onset of attacks. Simultaneous nausea, tolerance or even craving for specific foods occur in other conditions, particularly high altitude headaches which share other features of migraine attacks. The observations in this paper support the notion that migraine is a central neuronal metabolic disturbance.     

Long-latency auditory-evoked potentials: Role of polysensory association cortex in the cat

The objective of this study has been to define the role of polysensory association cortex in the generation of "wave NA" and of "wave C," long-latency auditory-evoked potentials recorded from the vertex of conscious cats as, respectively, a marked negative potential of latency 30-48 msec followed by a broad positive wave of latency 50-75 msec. Wave C may represent the feline analogue of the longer latency human auditory-evoked potential wave P2, insofar as both waveforms are very large amplitude, long duration positivities characterized by long recovery cycles. Based on previous studies of wave C and the generators of other middle-latency evoked potentials, we hypothesized that both wave NA and wave C might reflect, at least in part, the cortical culmination of a nonlemniscal line auditory association system arising in reticulothalamic projections to intralaminar and associated ventral thalamic regions. Relays from these thalamic areas are known to project to polysensory association cortex, including pericruciate gyrus, anterolateral gyrus, and medial suprasylvian gyrus. Therefore we implemented a series of lesion experiments to characterize the role of each of these cortical areas in the production of wave NA and wave C. Our results indicate that all three polysensory association areas contribute significantly to both waves NA and C, although the largest effects followed ablation of the pericruciate area alone. Thus, the generator substrates of waves NA and C appear to involve a long-recovery cycle system which functionally incorporates activation of association cortex.