Predicting Vertical Jump Height from Bar Velocity

The objective of the study was to assess the use of maximum (V_max) and final propulsive phase (FPV) bar velocity to predict jump height in the weighted jump squat. FPV was defined as the velocity reached just before bar acceleration was lower than gravity (-9.81 m·s^-2). Vertical jump height was calculated from the take-off velocity (V_take-off) provided by a force platform. Thirty swimmers belonging to the National Slovenian swimming team performed a jump squat incremental loading test, lifting 25%, 50%, 75% and 100% of body weight in a Smith machine. Jump performance was simultaneously monitored using an AMTI portable force platform and a linear velocity transducer attached to the barbell. Simple linear regression was used to estimate jump height from the V_max and FPV recorded by the linear velocity transducer. V_max (y = 16.577x - 16.384) was able to explain 93% of jump height variance with a standard error of the estimate of 1.47 cm. FPV (y = 12.828x - 6.504) was able to explain 91% of jump height variance with a standard error of the estimate of 1.66 cm. Despite that both variables resulted to be good predictors, heteroscedasticity in the differences between FPV and V_take-off was observed (r² = 0.307), while the differences between V_max and V_take-off were homogenously distributed (r² = 0.071). These results suggest that V_max is a valid tool for estimating vertical jump height in a loaded jump squat test performed in a Smith machine.

Key points

• Vertical jump height in the loaded jump squat can be estimated with acceptable precision from the maximum bar velocity recorded by a linear velocity transducer.
• The relationship between the point at which bar acceleration is less than -9.81 m·s^-2 and the real take-off is affected by the velocity of movement.
• Mean propulsive velocity recorded by a linear velocity transducer does not appear to be optimal to monitor ballistic exercise performance.

Key words: Linear velocity transducer, force platform, jump performance, swimming     

Interstitial 13q14 deletions detected in the karyotype and translocations with concomitant deletion at 13q14 in chronic lymphocytic leukemia: Different genetic mechanisms but equivalent poorer clinical outcome

Deletion of 13q14 as the sole abnormality is a good prognostic marker in chronic lymphocytic leukemia (CLL). Nonetheless, the prognostic value of reciprocal 13q14 translocations [t(13q)] with related 13q losses has not been fully elucidated. We described clinical and biological characteristics of 25 CLL patients with t(13q), and compared with 62 patients carrying interstitial del(13q) by conventional G‐banding cytogenetics (CGC) [i‐del(13q)] and 295 patients with del(13q) only detected by fluorescence in situ hybridization (FISH) [F‐del(13q)]. Besides from the CLL FISH panel (D13S319, CEP12, ATM, TP53), we studied RB1 deletions in all t(13q) cases and a representative group of i‐del(13q) and F‐del(13q). We analyzed NOTCH1, SF3B1, and MYD88 mutations in t(13q) cases by Sanger sequencing. In all, 25 distinct t(13q) were described. All these cases showed D13S319 deletion while 32% also lost RB1. The median percentage of 13q‐deleted nuclei did not differ from i‐del(13q) patients (73% vs. 64%), but both were significantly higher than F‐del(13q) (52%, P < 0.001). Moreover, t(13q) patients showed an increased incidence of biallelic del(13q) (52% vs. 11.3% and 14.9%, P < 0.001) and higher rates of concomitant 17p deletion (37.5% vs. 8.6% and 7.2%, P < 0.001). RB1 involvement was significantly higher in the i‐del(13q) group (79%, P < 0.001). Two t(13q) patients (11.8%) carried NOTCH1 mutations. Time to first treatment in t(13q) and i‐del(13q) was shorter than F‐del(13q) (67, 44, and 137 months, P = 0.029), and preserved significance in the multivariate analysis. In conclusion, t(13q) and del(13q) patients detected by CGC constitute a subgroup within the 13q‐deleted CLL patients associated with a worse clinical outcome. © 2014 Wiley Periodicals, Inc.     

DNA copy number alterations mark disease progression in paediatric chronic myeloid leukaemia

Early recognition of children with chronic phase chronic myeloid leukaemia (CML‐CP) at risk for developing a lymphoid blast crisis (LyBC) is desirable, because therapy options in CML‐LyBC are limited. We used Multiplex Ligation‐dependent Probe Amplification to determine whether B‐cell lymphoid leukaemia‐specific copy number alterations (CNAs) (e.g. IKZF1, PAX5, CDKN2A deletions) could be detected in CML‐CP and may be used to predict disease progression to LyBC. CNAs were detected in all patients with CML‐LyBC, but in none of the 77 patients with CML‐CP. Based on this study we conclude that CNAs remain a hallmark of disease progression.     

Functional mechanism of tracheal relaxation,antiasthmatic, and toxicological studies of 6-hydroxyflavone

Previously, we described tracheal rat rings relaxation by several flavonoids, being 6-hydroxyflavone (6-HOF) the most active derivative of the series. Thus, its mechanism of action was determined in an ex vivo tracheal rat ring bioassay. The anti-asthmatic effect was assayed in in vivo OVAlbumin (OVA)-sensitized guinea pigs. Finally, the toxicological profile of 6-HOF was studied based on Organization of Economic Cooperation and Development guidelines with modifications. 6-HOF–induced relaxation appears to be related with receptor-operated calcium channel and voltage-operated calcium channel blockade as the main mechanism of action, and also through the production of relaxant second messengers NO and cGMP. Molecular docking supports that 6-HOF acts as calcium channel blocker and by activation of nitric oxide synthase. In addition, the in vivo anti-asthmatic experiments demonstrate the dose-dependent significant anti-allergic effect of 6-HOF induced by OVA, with best activity at 50 /kg. Finally, toxicological studies determined a LD50 > 2,000 mg/kg and, after 28 day of treatment with 6-HOF (50 mg/kg) by intragastric route, mice did not exhibit evidence of any significant toxicity. In conclusion, experiments showed that 6-HOF exerts significant relaxant activity through calcium channel blockade, and possibly, by NO/cGMP-system stimulation on rat trachea, which interferes with the contraction mechanism of smooth muscle cells in the airways. In addition, the flavonoid shows potential anti-asthmatic properties in an anti-allergic pathway. Furthermore, because the pharmacological and safety evidence, we propose this flavonoid as lead for the development of a novel therapeutic agent for the treatment of asthma and related respiratory diseases.