Patients with primary orthostatic tremor (OT) experience a disabling sense of unsteadiness but rarely fall. In order to study the relationship between the development of subjective unsteadiness, objective unsteadiness and tremor, we recorded standing under four conditions (eyes open or closed, feet together or apart) in six patients with OT. Subjective unsteadiness was indicated by the patients on a four-point scale using a hand-held slider. Objective unsteadiness was assessed by measuring the path lengths of the centre of foot pressure and body motion at the level of the cervical spine. Tremor was measured by surface electromyography from leg and paraspinal muscles. OT patients were objectively more unsteady than controls. Objective unsteadiness also increased disproportionately in patients when standing with eyes closed. These findings suggest that balance control in OT is abnormal and shows increased visual dependence. Subjective unsteadiness increased from mild to severe over seconds to minutes. The increase was faster when standing with eyes closed or feet together. However, although escalating subjective unsteadiness was paralleled by an increase in leg tremor, there were no comparable changes in either paraspinal tremor or objective unsteadiness during the course of a stand. We conclude that there is a dissociation between subjective and objective unsteadiness. This implies that subjective unsteadiness does not arise simply from an awareness of increased body sway. We postulate that the sensation of unsteadiness arises from a tremulous disruption of proprioceptive afferent activity from the legs. This disturbance gives rise to increased co-contracting drive to the leg muscles in order to stiffen the joints and increase stability. Since muscle activity remains tremor-locked, the tremulous proprioceptive feedback is increased, which then further increases the sensation of unsteadiness, and so on in a vicious circle of escalating activity.
Objective. To visualize early experimental arthritis with near-infrared fluorescence (NIRF) imaging in a murine model of antigen-induced arthritis (AIA).Methods. The target of NIRF was the F4/80 antigen present on the surface of macrophages infiltrating the inflamed synovial membrane. Imaging was performed using anti-F4/80 monoclonal antibodies (mAb) labeled with Cy5.5 fluorochrome. On day 7 of AIA, 6 mice received an intravenous (IV) injection of labeled mAb; control AIA mice (n ؍ 6) received an IV injection of Cy5.5-labeled isotype control antibody. NIRF imaging was performed before injection (baseline) and until 72 hours thereafter. Histologic evaluation of arthritis severity and immunohistochemical assessment of F4/80 antigen density were also performed on day 7.Results. NIRF imaging showed an accumulation of fluorochrome probes in the inflamed knee joints and, to a lesser extent, in the contralateral (nonarthritic) knee joints. The signal induced by mAb F4/80 was clearly higher than that generated by the isotype control. Accumulation of fluorochrome probes in the joints was confirmed histologically by confocal laser scanning microscopy.Conclusion. The use of fluorochromes allows imaging of arthritis in the near-infrared range. Accumulation in the contralateral, nonarthritic knee joints can be explained by the presence of sentinel macrophages in normal synovium or by a mild contralateral response due to systemic activation or neurogenic mechanisms.
The study was performed to compare whole-body short time inversion recovery (STIR) MR imaging and (99m)Tc-methylene diphosphonate planar scintigraphy in the examination of children with suspected multifocal skeletal malignant lesions. Sixteen patients with known or suspected malignant skeletal disease underwent both whole-body STIR MR imaging and bone scintigraphy. The lesions were described and numbered according to scintigraphic evaluation criteria. Thus, 16 regions were analyzed in each patient for the comparison between the two modalities. Histology was proven in the primary malignant regions. Follow-up MRIs were registered. Scintigraphy and MRI follow-up were evaluated as gold standard. A total of 139 different lesions was observed by both modalities. Baseline whole-body MRI revealed 119 bone lesions in 256 possible sites (46.5%); scintigraphy revealed only 58 lesions (22.6%). Congruence was observed in only four patients (25%). According to the location of the lesion, correlation was observed in 39/139 lesions (28%). In all, 57.5% of the lesions were detected only by MRI and 14.5% of the lesions were detected only by scintigraphy. Whole-body MRI was more sensitive (P<0.001). Of all lesions numbered which could be separated in the initial MRI, whole-body MRI detected 178 lesions in the patients. The results suggest that whole-body MRI using a STIR sequence is an effective radiation free method for examination of children with suspected multifocal bone lesions. MRI showed more lesions than conventional (99m)Tc-methylene diphosphonate scintigraphy. Therefore, whole-body MRI may be feasible as a screening modality for metastatic and skip lesions in osteosarcoma, PNET, Ewing sarcoma and Langerhans cell histiocytosis in children.
Multidetector CT angiography offers high diagnostic accuracy-equivalent to that of DSA-in the detection of intracranial aneurysms. Also, the possibility of coil embolization can be reliably determined with multidetector CT angiography.
NIRF imaging with Cy5.5 can identify arthritic joints in vivo, likely due to nonspecific deposition.
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