Coordination tests in persons with acute central nervous system pathology: assessment of interrater reliability and known-group validity.

BACKGROUND AND PURPOSE: Coordination testing is a standard part of the neurologic examination, yet the psychometric properties of many tests used by practitioners are unknown. This study investigated the interrater reliability and known-group validity of limb coordination tests in participants with acute central nervous system (CNS) pathology. METHODS: Twenty-five participants with CNS pathology completed 20 different limb coordination tests administered at bedside by a physical therapist. Examinations were videotaped and independently rated by a neurologist, a physical therapist, and a student physical therapist using a 5-point ordinal scale. Nine tests were also timed. Results were analyzed for interrater reliability and the degree to which they differed between groups categorized as having or not having coordination deficits. RESULTS: Participants were individuals who had been diagnosed with either a CNS vascular lesion or intracranial tumor. Timed test scores had higher levels of agreement (mean intraclass correlation coefficient [ICC], 0.69-0.97) than ordinal scores (mean κfree 0.56-0.91). Scores from 5 of the 9 timed measures and 8 of the 20 ordinal measures differed between groups. DISCUSSION AND CONCLUSIONS: Eleven tests were scored reliably between raters (κ > 0.60 or ICC > 0.75) and were performed differently between groups with and without coordination deficits (P ≤ 0.05). These tests are recommended for use when examining patients with acute neurologic pathology from a vascular lesion or tumor. They are simple to perform and require only a stopwatch to complete. Future studies should explore the sensitivity and specificity of these tests in disease states and their correlation with functional measures.

Stroke and atrial fibrillation following cardiac surgery.

OBJECTIVE: Stroke is an occasional devastating complication of cardiac surgery. Transient atrial fibrillation (AF) is a frequent complication of cardiac surgery. Emboli originating from the fibrillating left atrium are a known cause of stroke in the non-surgical setting. The purpose of this quality improvement initiative, conducted by the Wausau Heart Institute, was to characterize strokes after cardiac surgery and to investigate the relationship between AF and the occurrence of postoperative strokes. METHODS: We conducted a retrospective record review of all patients undergoing cardiac surgery utilizing cardiopulmonary bypass without associated carotid surgery at our institution between January 1, 1993 and June 30, 1999. The occurrence of strokes and AF was noted. The timing of the AF (duration and relationship to surgery) was recorded. RESULTS: Of the 2104 eligible patients, strokes occurred in 68 (3.2%). In 18 patients (27%), stroke was immediately apparent as the patient recovered from anesthesia (intra-operative stroke). Fifty of the 68 strokes (74%) were acquired following the immediate operative period after the patient awoke from anesthesia neurologically intact (postoperative stroke). Postoperative stroke occurred in 2.1% of patients undergoing coronary bypass surgery only, in 2.2% if valve surgery only was performed, and 4.6% if both valve and bypass surgery were performed. AF occurred in 700 patients (33%). The incidence of postoperative stroke was 5.4% in patients with AF and 0.89% in those without AF (P < 0.001). Of those patients suffering a postoperative stroke, 76% had AF following cardiac surgery, compared to 32% if a postoperative stroke did not occur (P < 0.001). Carotid bruits were present in 7 (14%) of the patients with postoperative stroke. Carotid ultrasound studies were performed in 32 patients (63%) and a lesion of > 70% was found in 8 patients (25%). Cerebral lesions contralateral to the stenotic carotid artery occurred in 3 of these 8 patients. CONCLUSION: Most strokes complicating cardiac surgery occur in patients without significant carotid disease, and are acquired after the patient awakens neurologically intact. The high incidence of postoperative AF in these patients suggests a possible embolic cause for some of the strokes. As such, some postoperative strokes may be preventable.

Analysis of mitochondria isolated from single cells.

Bulk studies are not suitable to describe and study cell-to-cell variation, which is of high importance in biological processes such as embryogenesis, tissue differentiation, and disease. Previously, capillary electrophoresis with laser-induced fluorescence detection (CE-LIF) was used to measure the properties of organelles isolated from millions of cells. As such, these bulk measurements reported average properties for the organelles of cell populations. Similar measurements for organelles released from single cells would be highly relevant to describe the subcellular variations among cells. Toward this goal, here we introduce an approach to analyze the mitochondria released from single mammalian cells. Osteosarcoma 143B cells are labeled with either the fluorescent mitochondrion-specific 10-N-nonyl acridine orange (NAO) or via expression of the fluorescent protein DsRed2. Subsequently, a single cell is introduced into the CE-LIF capillary where the organelles are released by a combined treatment of digitonin and trypsin. After this treatment, an electric field is applied and the released organelles electromigrate toward the LIF detector. From an electropherogram, the number of detected events per cell, their individual electrophoretic mobilities, and their individual fluorescence intensities are calculated. The results obtained from DsRed2 labeling, which is retained in intact mitochondria, and NAO labeling, which labels all mitochondria, are the basis for discussion of the strengths and limitations of this single-cell approach.

Effect of body mass index on insulin resistance and lipids in prepubertal and postpubertal children: SCHOOL observations.

As part of the School Children Have Early Onset of Leading Risk Factors for Cardiovascular Disease and Diabetes Mellitus (SCHOOL) project, this study examines the effect of elevated body mass index on metabolic parameters and its relationship to insulin resistance in prepubertal and postpubertal students from the Wausau School District in central Wisconsin. Two hundred forty-seven nondiabetic students were randomly selected (125 prepubertal [2nd graders] and 122 postpubertal [11th graders]). Waist/hip ratio and body mass index corrected for age and sex were calculated. Fasting insulin, glucose, and nuclear magnetic resonance lipid profiles were measured. Relative insulin resistance was defined as quantitative insulin sensitivity check index > 1 SD below the mean of normal-weight children. Twenty-eight percent of 2nd graders and 33% of 11th graders were overweight. Relative insulin resistance was present in 47% of overweight 2nd graders and 51 % of overweight 11th graders and was associated with higher triglycerides, lower high-density lipoprotein, smaller low-density lipoprotein particles and, in 11th graders, higher waist/hip ratio. Relative insulin resistance prevalence is high among overweight children and adolescents. Biomarkers of increased risk of adverse cardiovascular outcomes are already present in overweight school children.

Within the cell: analytical techniques for subcellular analysis.

This review covers recent developments in the preparation, manipulation, and analyses of subcellular environments. In particular, it highlights approaches for (1) separation and detection of individual organelles, (2) preparation of ultra-pure organelle fractions, and (3) utilization of novel labeling strategies. These approaches, based on innovative technologies such as microfluidics, immunoisolation, mass spectrometry and electrophoresis, suggest that subcellular analyses will soon become as commonplace as single cell and bulk cellular assays.

Capillary electrophoretic separation of nuclei released from single cells.

We report here the first capillary electrophoresis analysis of intact nuclei released on-column from single cells. Expression of the nuclear-targeted protein nuDsRed2 and the plasma membrane-bound farnesylated enhanced green fluorescent protein in cultured human DeltaH2-1 cells allowed fluorescent monitoring of the fate of these subcellular compartments upon injection of a single cell into the separation capillary. On-column treatment with digitonin allowed for the separation of the plasma membrane from the nucleus as indicated by their selective laser-induced fluorescence detection in two separate spectral regions. The data suggest that less than 0.1% of the plasma membrane remains bound to individually detected nuclei. In digitonin-treated cells, the electropherograms consisted of a prominent fluorescent peak attributed to nuDsRed2 localized to the nucleus and a collection of weakly fluorescent events (barely distinguishable from scattering) that seem to indicate additional localization of this protein to other subcellular regions. Taken together, this report points to the feasibility of studying intact organelles released from a single mammalian cell by capillary electrophoresis, which is a prerequisite to understanding the relevance of subcellular heterogeneity in biological systems.