Contribution of Visual Information about Ball Trajectory to Baseball Hitting Accuracy.

The contribution of visual information about a pitched ball to the accuracy of baseball-bat contact may vary depending on the part of trajectory seen. The purpose of the present study was to examine the relationship between hitting accuracy and the segment of the trajectory of the flying ball that can be seen by the batter. Ten college baseball field players participated in the study. The systematic error and standardized variability of ball-bat contact on the bat coordinate system and pitcher-to-catcher direction when hitting a ball launched from a pitching machine were measured with or without visual occlusion and analyzed using analysis of variance. The visual occlusion timing included occlusion from 150 milliseconds (ms) after the ball release (R+150), occlusion from 150 ms before the expected arrival of the launched ball at the home plate (A-150), and a condition with no occlusion (NO). Twelve trials in each condition were performed using two ball speeds (31.9 m·s-1 and 40.3 m·s-1). Visual occlusion did not affect the mean location of ball-bat contact in the bat's long axis, short axis, and pitcher-to-catcher directions. Although the magnitude of standardized variability was significantly smaller in the bat's short axis direction than in the bat's long axis and pitcher-to-catcher directions (p < 0.001), additional visible time from the R+150 condition to the A-150 and NO conditions resulted in a further decrease in standardized variability only in the bat's short axis direction (p < 0.05). The results suggested that there is directional specificity in the magnitude of standardized variability with different visible time. The present study also confirmed the limitation to visual information is the later part of the ball trajectory for improving hitting accuracy, which is likely due to visuo-motor delay.

The Asian project for collaborative derivation of reference intervals: (1) strategy and major results of standardized analytes.

BACKGROUND: A multicenter study conducted in Southeast Asia to derive reference intervals (RIs) for 72 commonly measured analytes (general chemistry, inflammatory markers, hormones, etc.) featured centralized measurement to clearly detect regionality in test results. The results of 31 standardized analytes are reported, with the remaining analytes presented in the next report. METHOD: The study included 63 clinical laboratories from South Korea, China, Vietnam, Malaysia, Indonesia, and seven areas in Japan. A total of 3541 healthy individuals aged 20-65 years (Japan 2082, others 1459) were recruited mostly from hospital workers using a well-defined common protocol. All serum specimens were transported to Tokyo at -80°C and collectively measured using reagents from four manufacturers. Three-level nested ANOVA was used to quantitate variation (SD) of test results due to region, sex, and age. A ratio of SD for a given factor over residual SD (representing net between-individual variations) (SDR) exceeding 0.3 was considered significant. Traceability of RIs was ensured by recalibration using value-assigned reference materials. RIs were derived parametrically. RESULTS: SDRs for sex and age were significant for 19 and 16 analytes, respectively. Regional difference was significant for 11 analytes, including high density lipoprotein (HDL)-cholesterol and inflammatory markers. However, when the data were limited to those from Japan, regionality was not observed in any of the analytes. Accordingly, RIs were derived with or without partition by sex and region. CONCLUSIONS: RIs applicable to a wide area in Asia were established for the majority of analytes with traceability to reference measuring systems, whereas regional partitioning was required for RIs of the other analytes.

Serum remnant lipoprotein cholesterol/triglyceride ratio as an index for screening familial type III hyperlipidaemia.

BACKGROUND: An elevated serum remnant lipoprotein cholesterol (RLP-C)/triglyceride (TG) ratio has not been evaluated as an index of familial type III hyperlipidaemia defined by the presence of beta-VLDL and apolipoprotein (Apo) E2/2 phenotype in the Japanese hyperlipidaemic population. METHODS: Serum lipids and lipoproteins from 514 individuals (200 men and 314 women, mean age 58 years) with total cholesterol >6.22 mmol/L and TG between 2.26 mmol/L and 9.04 mmol/L, selected from 25,080 subjects visiting the clinics for health checkup were analysed for a possible relationship with familial type III hyperlipoproteinaemia. RESULTS: Median RLP-C concentration and RLP-C/TG ratio were 0.30 and 0.11 mmol/L, respectively. When compared between subjects with (31 cases) and without (483 cases) a broad-beta band on electrophoresis, the RLP-C concentrations and RLP-C/TG ratio were 0.77 +/- 0.43 mmol/L versus 0.34 +/- 0.16 mmol/L (P<0.0001) and 0.15 +/- 0.023 versus 0.11 +/- 0.027 (P<0.0001), respectively. Three cases with broad-beta band positive (the presence of beta-VLDL) showed RLP-C/TG ratio greater than 0.23 and RLP-C greater than 0.78 mmol/L, suggestive of type III hyperlipoproteinaemia, despite a lack of characteristic Apo E2/2 homozygosity. Cases with Apo E/Apo CIII ratio greater than 1.0 were not detected in this study group. CONCLUSION: Serum RLP-C concentration and RLP-C/TG ratio, together with Apo E/Apo CIII ratio appear to be useful for screening familial type III hyperlipidaemia in the Japanese hyperlipidaemic population.

Technical and clinical characterization of the Bio-PTH (1-84) immunochemiluminometric assay and comparison with a second-generation assay for parathyroid hormone.

BACKGROUND: The Bio-Intact parathyroid hormone (1-84) assay (Bio-PTH), a newly developed two-site immunochemiluminometric assay, measures exclusively PTH (1-84) in contrast to second-generation "intact PTH" (I-PTH) assays. We investigated the technical performance and clinical significance of this new assay. METHODS: PTH was measured simultaneously by the Bio-PTH assay and Allegro intact PTH IRMA in sera from Japanese patients with calcium disorders. RESULTS: Measured Bio-PTH in serum was unaffected by six freeze-thaw cycles and was stable at 4 degrees C for 7 days and during storage at -20 or -80 degrees C over 28 days. The calibration curve was linear to 1800 ng/L. The detection limit was 3.9 ng/L. The intra- and interassay imprecision was <2.8% and 3.5%, respectively, for analyte concentrations spanning the range of the calibration curve. Bio-PTH was unaffected by a 1000-fold excess of PTH (7-84), although I-PTH reacted equally with PTH (7-84) and PTH (1-84). Bio-PTH was correlated with I-PTH in healthy individuals (r = 0.953; P <0.0001; n = 26) and in the full population without renal dysfunction (r = 0.994; P <0.0001; n = 62). In 72 volunteers, mean (SD) Bio-PTH was 22.2 (7.1) ng/L, or 62% of the mean I-PTH [36.1 (22.3) ng/L]. This ratio was 51% in hemodialysis patients (n = 177). Mean Bio-PTH was high in patients with primary hyperparathyroidism [121 (85) ng/L; n = 18] and hemodialysis patients [102 (104) ng/L; n = 177], low in idiopathic hypoparathyroidism [5.5 (2.8) ng/L; n = 4], and within 2 SD of the mean for healthy controls in Paget disease of the bone [34 (15) ng/L; n = 9] and bone metastasis [24 (12) ng/L; n = 8]. CONCLUSION: The Bio-PTH assay is sensitive and precise and produces expected results for patients with the studied disorders of calcium metabolism.