Normal expression of the Fanconi anemia proteins FAA and FAC and sensitivity to mitomycin C in two patients with Seckel syndrome

Seckel syndrome is a rare autosomal recessive disorder. The classical presentation includes pre- and postnatal growth deficiency, mental retardation, and characteristic facial appearance. There have been several reports of associated hematological abnormalities and chromosomal breakage, findings suggestive of Fanconi anemia (FA). We tested for these findings in two Arabic patients with this syndrome. We compared the growth profile of lymphoblastoid cells from our patients and their parents with the FA group A cell line HSC72 in the presence and absence of mitomycin C (MMC). By Western analysis, we also determined the expression of FAA and FAC, two FA disease gene products that together account for approximately 80% of FA. Unlike HSC72 cells, cells from the patients were resistant to MMC, and both FAA and FAC proteins were expressed at similar levels in all cell lines. There is an increasing recognition of clinical variability and perhaps genetic heterogeneity in Seckel syndrome. Our results demonstrate that cross-link sensitivity comparable to FA is not a uniform finding in patients with Seckel syndrome.     

The value of deletion analysis for carrier detection in Duchenne muscular dystrophy (DMD)

We performed genetic analysis for carrier detection for several at-risk females in a four-generation Duchenne muscular dystrophy (DMD) pedigree using deletion analysis. We demonstrated that dosage analysis is a suitable alternative method to determine the carrier status of female relatives of DMD patients shown to have a deletion within the DMD gene. Subsequently, we diagnosed an affected male fetus for an at-risk female shown to be a DMD carrier by deletion analysis. The usefulness of deletion and linkage analysis are compared. In this family, linkage analysis was complicated by the unavailability of key family members, two recombination events and by previously undisclosed nonpaternity. We found that dosage analysis was more efficient than linkage for carrier evaluation in this family.     

Functional mapping of the human globus pallidus: contrasting effect of stimulation in the internal and external pallidum in Parkinson's disease

Our objective was to elaborate a functional map of the globus pallidus by correlating the intrapallidal localization of quadripolar electrodes implanted in parkinsonian patients with the clinical effect of the stimulation of each contact. Five patients with L-DOPA-responsive Parkinson's disease presenting severe motor fluctuations and L-DOPA-induced dyskinesias were treated by continuous bilateral high-frequency stimulation of the globus pallidus. The effects of stimulation on parkinsonian disability were tested through each of the four stimulating contacts of each electrode. The anatomical localization of each of the stimulating contacts was determined by confronting the pre- and post-operative magnetic resonance imaging with the anatomical atlas of Schaltenbrand and Wharen.(34) The registration procedure comprised digitization of the atlas, the use of deformation tools to fit atlas sections with magnetic resonance imaging sections, and three-dimensional reconstruction of both the atlas and the magnetic resonance imaging sections. Analysis of the 32 stimulating contacts tested did not reveal a somatotopic organization in the pallidal region investigated but demonstrated that high-frequency stimulation had contrasting effects depending on whether it was applied to the external or the internal pallidum. Akinesia was improved by stimulation of the external pallidum but worsened by stimulation of the internal pallidum. In contrast, parkinsonian rigidity was improved by stimulation of either part of the pallidum. The areas in the internal pallidum where stimulation worsened akinesia were those in which stimulation reduced or suppressed L-DOPA-induced dyskinesias. Conversely, stimulation applied to the external pallidum induced dyskinesias. The fact that rigidity was improved by stimulation of the internal and external pallidum suggests that the neuronal bases of parkinsonian rigidity are different from those of akinesia and dyskinesias. The effect on akinesia and dyskinesias is in agreement with the current model of basal ganglia circuitry(10) if high-frequency stimulation activates rather than inhibits pallidal neurons, a possibility which is very likely since there are marked anatomical, biochemical and electrophysiological differences between the globus pallidus and the subthalamic nucleus.This study demonstrates that high-frequency stimulation of the globus pallidus in parkinsonian patients has contrasting effects depending on whether it is applied to the external or the internal part of this nucleus. The effect on akinesia and dyskinesias suggests that stimulation activates pallidal neurons, a result which challenges the generally accepted concept that high-frequency stimulation inactivates neurons in the region stimulated.     

Bilateral vertebral artery occlusion following cervical spine trauma--case report

A 41-year-old female presented with a rare case of bilateral vertebral artery occlusion following C5-6 cervical spine subluxation after a fall of 30 feet. Digital subtraction angiography showed occlusion of the bilateral vertebral arteries. Unlocking of the facet joint, posterior wiring with iliac crest grafting, and anterior fusion were performed. The patient died on the 3rd day after the operation. This type of injury has a grim prognosis with less than a third of the patients achieving a good outcome.     

Axial parkinsonian symptoms can be improved: the role of levodopa and bilateral subthalamic stimulation

OBJECTIVE: To assess the effects of high frequency stimulation of the subthalamic nucleus (STN) on axial symptoms occurring in advanced stages of Parkinson's disease (PD). METHODS: The efficacy of STN stimulation on total motor disability score (unified Parkinson's disease rating scale (UPDRS) part III) were evaluated in 10 patients with severe Parkinson's disease. The subscores were then studied separately for limb akinesia, rigidity, and tremor, which are known to respond to levodopa, and axial signs, including speech, neck rigidity, rising from a chair, posture, gait, and postural stability, which are known to respond less well to levodopa. Patients were clinically assessed in the "off" and "on" drug condition during a levodopa challenge test performed before surgical implantation of stimulation electrodes and repeated 6 months after surgery under continuous STN stimulation. A complementary score for axial symptoms from the "activities of daily living" (ADL)-that is, speech, swallowing, turning in bed, falling, walking, and freezing-was obtained from each patient's questionnaire (UPDRS, part II). RESULTS: Improvements in total motor disability score (62%), limb signs (62%), and axial signs (72%) obtained with STN stimulation were statistically comparable with those obtained with levodopa during the preoperative challenge (68%, 69%, and 59%, respectively). When levodopa and STN stimulation were combined there was a further improvement in total motor disability (80%) compared with preoperative levodopa administration. This consisted largely of an additional improvement in axial signs (84%) mainly for posture and postural stability, no further improvement in levodopa responsive signs being found. Axial symptoms from the ADL showed similar additional improvement when levodopa and STN stimulation were combined. CONCLUSION: These findings suggest that bilateral STN stimulation improves most axial features of Parkinson's disease and that a synergistic effect can be obtained when stimulation is used in conjunction with levodopa treatment.