A speed-based approach to vestibular rehabilitation for peripheral vestibular hypofunction: A retrospective chart review.

BACKGROUND: Current vestibular rehabilitation for peripheral vestibular hypofunction is an exercise-based approach that improves symptoms and function in most, but not all patients, and includes gaze stabilization exercises focused on duration of head movement. One factor that may impact rehabilitation outcomes is the speed of head movement during gaze stability exercises. OBJECTIVE: Examine outcomes of modified VOR X1 exercises that emphasize a speed-based approach for gaze stabilization while omitting substitution and habituation exercises. Balance training focused on postural realignment and hip strategy performance during altered visual and somatosensory inputs. METHODS: A retrospective chart review of 159 patients with vestibular deficits was performed and five outcome measures were analyzed. RESULTS: All outcomes - self-report dizziness and balance function, dynamic gait index, modified clinical test of sensory interaction and balance, and clinical dynamic visual acuity improved significantly and approached or achieved normal scores. CONCLUSIONS: The combination of modified VOR X1 gaze stability exercises, wherein patients achieved high-velocity head movement (240°/s) during short exercise bouts, with "forced use" gait and balance exercises for postural realignment and hip strategy recruitment, achieved 93-99% of normal scores for all five outcomes. These results compare favorably to the outcomes for current VR techniques and warrant further investigation.

Distance of the internal central venous catheter tip from the right atrium is positively correlated with central venous thrombosis.

Central venous catheters (CVCs) are associated with occlusive, infectious, and thrombotic complications. The aim of this study was to determine if internal CVC tip position was correlated with subsequent complications. This was an institutional review board approved single-center retrospective review of 169 consecutive patients who underwent placement of 203 semipermanent CVCs. Using post-placement chest X-rays, a de novo scale of internal catheter tip position was developed. Major complications were recorded. A logistic regression analysis was used to determine if catheter tip position predicted subsequent complications. There were 78 men and 91 women with a mean age of 48 ± 11 years. There were 21 catheter tips placed in the subclavian/innominate veins, 32 in the upper superior vena cava, 113 in the atriocaval junction, and 37 in the right atrium. There were 83 complications occurring in 61 (36.1 %) patients, including sepsis in 40 (23.7 %), venous thrombosis in 18 (10.7 %), catheter occlusion in 16 (9.5 %), internal catheter repositioning in 6 (3.6 %), pneumothorax in 2 (1.2 %), and death in 1 (0.6 %). An internal catheter tip position peripheral to the atriocaval junction resulted in a catheter that was more likely to undergo internal repositioning (p < 0.001) and venous thrombosis (p < 0.001). Patients with femoral catheters were more likely to develop sepsis (45 %) than patients whose catheters were inserted through the upper extremity veins (18 %) (p < 0.01). In conclusion, to reduce catheter-associated morbidity and potentially mortality, the internal catheter tip should be positioned at the atriocaval junction or within the right atrium and femoral insertion sites should be avoided whenever possible.

Energy migration study of random immobile anthracene derivatives by time-resolved fluorescence anisotropy decays.

We describe time-resolved fluorescence anisotropy measurements for a simple 2-substituted anthracene derivative (2-An-M) as a function of concentration in poly(methyl methacrylate) (PMMA) films. The anisotropy decays via energy migration among 2-An-M molecules in the matrix. The data were interpreted in terms of the survival probability of the initially excited chromophores and are in good agreement with the plot predicted using R0 = 1.8 nm, the value of the Förster radius determined independently by the spectral overlap method. For all concentrations, we found r0 = 0.20 +/- 0.01 for the initial anisotropy at time zero, whereas the residual anisotropy, r(infinity), was concentration-dependent and higher in magnitude than the theoretically predicted value, 4% of r0. The higher residual anisotropy values may originate from the possibility that not all of the anthracene molecules are involved in the energy migration process. Similar anthracene anisotropy experiments were performed on anthracene-labeled poly(isoprene-b-methyl methacrylate) (PI-PMMA). The results show an increased depolarization rate for samples containing a higher fraction of polymers labeled at the junction with anthracene chromophores.

The determination of the Förster distance (R0) for phenanthrene and anthracene derivatives in poly(methyl methacrylate) films.

Experiments that employ direct resonance energy transfer (DET) to obtain information about distances or domain sizes in polymer systems require independent information about the magnitude of the characteristic (Förster) energy transfer distance R(0). Values of R(0) are relatively straightforward to obtain by the traditional spectral overlap method (R(0)(SO)) for dyes in fluid solution, but are much more difficult to obtain for dyes in rigid polymer films. Here one can obtain a value for R(0) as a fitting parameter (R(0)(FF)) for donor fluorescence decay experiments for samples containing a random distribution of donor and acceptor dyes in the polymer film. In previous experiments from our group, we needed values of R(0) for various phenanthrene (Phe, donor) and anthracene (An, acceptor) derivatives. In this paper, we describe experiments which determine R(0) values by both methods for a series of Phe-An donor-acceptor pairs in poly(methyl methacrylate) and polystyrene films. Both the location of substituents on the donor and acceptor as well as the choice of the medium had an effect on the measured R(0), which varied between 2.0 and 2.6 nm. We also ascertained that there is some unknown factor, also prevalent in the work of others, which results in the Förster radius being larger when determined by the Förster fit method than by the method of spectral overlap.

Validation of a near-infrared transmission spectroscopic procedure. Part B: Application to alternate content uniformity and release assay methods for pharmaceutical solid dosage forms.

NIR analytical methods can be validated to meet the requirement of demonstrating that it is suitable for the analysis of the materials for which it is being used. Applying previously described protocols for NIR methods to the analysis of two types of pharmaceutical products shows that for these products, NIR is suitable as an alternate analytical method for assay and for content uniformity.

Validation of a near-infrared transmission spectroscopic procedure, part A: validation protocols.

It is possible to devise calibration and validation protocols that enable the ICH guidelines to conform to the specialized requirements of the NIR method of analysis. Some of the required characteristics of evaluation specified by the guidelines, such as accuracy and repeatability, can be applied directly, just as with any other analytical method. Other characteristics are adapted through the novel use of specialized statistics, or through the use of creative methods and procedures to match the recommendations of the guidelines to the unique and specialized requirements of the NIR method.