Transmission infrared spectroscopy for rapid quantification of fat, protein, and lactose concentrations in human milk.

OBJECTIVE: To develop partial least squares regression (PLSR) calibration models in combination with transmission infrared (TIR) spectroscopy for rapid and optimal quantification of human milk macronutrient concentrations. STUDY DESIGN: Human milk samples (n = 306) were characterized simultaneously by reference chemical analytical methods and TIR spectroscopy. Reference macronutrient concentrations were linked to pre-processed spectra and divided into two (training and test) sets. PLSR was used to develop trial calibration models using training set, and the test set was used to assess the accuracy of the trial analytical methods. RESULTS: For the methods selected as optimal, the concordance correlation coefficients between reference and TIR-based methods were 0.93 for fat, 0.96 for protein, and 0.52 for lactose. The Bland-Altman plots showed no evidence of systematic bias between TIR and reference methods. CONCLUSIONS: TIR spectroscopy provides the basis for accurate and rapid quantification of human milk fat and protein concentrations but is less accurate for measuring lactose concentration.

Centrifugal ultrafiltration of human serum for improving immunoglobulin A quantification using attenuated total reflectance infrared spectroscopy.

Attenuated total reflectance infrared (ATR-IR) spectroscopy is a simple, rapid and cost-effective method for the analysis of serum. However, the complex nature of serum remains a limiting factor to the reliability of this method. We investigated the benefits of coupling the centrifugal ultrafiltration with ATR-IR spectroscopy for quantification of human serum IgA concentration. Human serum samples (n = 196) were analyzed for IgA using an immunoturbidimetric assay. ATR-IR spectra were acquired for whole serum samples and for the retentate (residue) reconstituted with saline following 300 kDa centrifugal ultrafiltration. IR-based analytical methods were developed for each of the two spectroscopic datasets, and the accuracy of each of the two methods compared. Analytical methods were based upon partial least squares regression (PLSR) calibration models - one with 5-PLS factors (for whole serum) and the second with 9-PLS factors (for the reconstituted retentate). Comparison of the two sets of IR-based analytical results to reference IgA values revealed improvements in the Pearson correlation coefficient (from 0.66 to 0.76), and the root mean squared error of prediction in IR-based IgA concentrations (from 102 to 79 mg/dL) for the ultrafiltration retentate-based method as compared to the method built upon whole serum spectra. Depleting human serum low molecular weight proteins using a 300 kDa centrifugal filter thus enhances the accuracy IgA quantification by ATR-IR spectroscopy. Further evaluation and optimization of this general approach may ultimately lead to routine analysis of a range of high molecular-weight analytical targets that are otherwise unsuitable for IR-based analysis.

Colored Glasses to Mitigate Photophobia Symptoms Posttraumatic Brain Injury.

CONTEXT: After a concussion or mild traumatic brain injury (mTBI), patients often suffer from light sensitivity, or photophobia, which contributes to decreased quality of life post-mTBI. Whereas sunglasses may provide some relief from photophobia, they are not practical indoors or in low light. A light-mitigation strategy can be easily used indoors as needed to optimize the relief. We have found that many photophobic patients experience relief using colored sunglasses. OBJECTIVE: To provide the athletic trainer with a means and method to assess whether an athlete is suffering from photophobia after concussion and to determine if colored glasses provide relief. DESIGN: Cross-sectional study. SETTING: Rehabilitation clinic. PATIENTS OR OTHER PARTICIPANTS: Fifty-one patients being treated after concussion. INTERVENTION(S): We assessed postconcussion patients for visual symptoms including photophobia and photosensitivity. Off-the-shelf glasses were used to determine whether specific colors provided relief from photophobia. Screening was done using a penlight and multiple pairs of colored glasses. MAIN OUTCOME MEASURE(S): Self-reported mitigation of photophobia symptoms and the specific color frequency that reduced symptoms in each individual. RESULTS: Of the 39 patients studied who had visual symptoms, 76% complained of photophobia. Using glasses of 1 or more colors, symptoms were relieved in 85% of patients reporting photophobia. The colors that provided the most relief were blue, green, red, and purple. No adverse events were reported. CONCLUSIONS: An empirical assessment of frequency-specific photophobia is easy to perform. A traditional penlight is used to elicit photophobia and then the colored glasses are tested for optimal relief. Frequency-specific photophobia can be reduced with a strategy of light-mitigation therapy, including colored glasses, sunglasses, hats, and light avoidance. This, we believe, helps to improve the patient's quality of life and may aid in the recovery process. More work is needed to identify the best colors and methods of mitigating frequency-specific photophobia.

Exploration of attenuated total reflectance mid-infrared spectroscopy and multivariate calibration to measure immunoglobulin G in human sera.

Immunoglobulin G (IgG) is crucial for the protection of the host from invasive pathogens. Due to its importance for human health, tools that enable the monitoring of IgG levels are highly desired. Consequently there is a need for methods to determine the IgG concentration that are simple, rapid, and inexpensive. This work explored the potential of attenuated total reflectance (ATR) infrared spectroscopy as a method to determine IgG concentrations in human serum samples. Venous blood samples were collected from adults and children, and from the umbilical cord of newborns. The serum was harvested and tested using ATR infrared spectroscopy. Partial least squares (PLS) regression provided the basis to develop the new analytical methods. Three PLS calibrations were determined: one for the combined set of the venous and umbilical cord serum samples, the second for only the umbilical cord samples, and the third for only the venous samples. The number of PLS factors was chosen by critical evaluation of Monte Carlo-based cross validation results. The predictive performance for each PLS calibration was evaluated using the Pearson correlation coefficient, scatter plot and Bland-Altman plot, and percent deviations for independent prediction sets. The repeatability was evaluated by standard deviation and relative standard deviation. The results showed that ATR infrared spectroscopy is potentially a simple, quick, and inexpensive method to measure IgG concentrations in human serum samples. The results also showed that it is possible to build a united calibration curve for the umbilical cord and the venous samples.

Effects of postural control manipulation on visuomotor training performance: comparative data in healthy athletes.

PURPOSE/BACKGROUND: Visuomotor ability is an important parameter for neurologic function and effective sport performance. Adding a balance challenge during a structured eye-hand coordination task, such as hitting lights on a light board (Dynavision™), has not been previously reported. Using Division I football players, the aim of this study was to determine normative data on a dual-task performance regimen combining a visuomotor light board task with a balance task. The intent is to use such normative data and baseline data as part of a concussion management program. METHODS: Division I college football team members, n=105, were consented. Subjects first performed Dynavision™ D2™ Visuomotor Training Device (D2™) eye-hand coordination tasks, the A* and the RT; they then performed the same tasks with an added balance challenge, standing on a BOSU® ball. RESULTS: Ninety-four athletes completed the full testing procedure on the D2™ system. The mean score of the A* test was 93 ± 11.0 hits per minute; and the mean on the A* test with the added BOSU® balance challenge was 83.7 ± 9.2 hits per minute. The mean RT time was 0.33 ± 0.036 seconds. Mean reaction time increased to 0.38 ± 0.063 while the subject stood on the BOSU® ball. Performance on the D2™ A* and RT were both statistically significantly different in the dual task condition (p<0.05). CONCLUSIONS: Results show an approximate 10% decline in D2™ performance when healthy individuals stand on a BOSU® ball. From the data presented here, the authors determined that there is a 10% decrement in performance when one's balance is challenged on the BOSU® ball. A fall in performance of substantially greater than 10% may indicate abnormal vestibulocerebellar regulatory processing of balance and motion. Further research, using these normative data is needed to determine more specific parameters for definitions of impairment and return-to-play and if there is utility for such studies as part of a concussion management program. LEVEL OF EVIDENCE: III.