Factors Associated With a Lateral Ankle Sprain in Young Female Soccer Players: A Prospective Cohort Study

Background

Previous studies have attempted to determine if certain risk factors can predict the occurrence of a lateral ankle sprain (LAS) in female soccer players. Unfortunately, there is limited evidence with regard to risk factors associated with an LAS in female soccer players.

Purpose

To identify intrinsic risk factors for an LAS among young female soccer players.

Study Design

Cohort study; Level of evidence, 2.

Methods

Participants were 161 young female soccer players in Japan who were evaluated for LAS risk factors during a preseason medical assessment. The assessment included anthropometric, joint laxity, joint range of motion, muscle flexibility, muscle strength, and balance measurements. Each athlete's history of LASs was also collected. The participants were monitored during a single-yearseason for LASs, as diagnosed by physicians.

Results

There were 26 instances of an LAS in 25 players (15.5%) during the season. Injured players were significantly more likely to have sustained a previous ankle sprain (P = .045) and demonstrated significantly worse balance than their peers without an LAS during the double- and single-leg balance tests (P = .008 for both). Athletes with lower hamstring-to-quadriceps muscle strength ratios were also significantly more likely to sustain an LAS (P = .02).

Conclusion

Poor balance, a low hamstring-to-quadriceps ratio, and a history of ankle sprains were associated with an increased risk of LASs in young female soccer players in the current study. These findings may be useful for developing a program to prevent LASs in this population.

Lower hamstring to quadriceps muscle strength ratio and lower body weight as factors associated with noncontact anterior cruciate ligament injury in male American football players: A prospective cohort study

Background

Previous studies have aimed to determine the use of certain risk factors in predicting the occurrence of noncontact anterior cruciate ligament (ACL) injuries. Unfortunately, evidence regarding noncontact ACL injuries in male American football players is limited. This prospective cohort study aimed to identify intrinsic risk factors for noncontact ACL injury among male American football players.

Methods

This study evaluated 152 male American football players in Japan for potential noncontact ACL injury risk factors during a preseason medical assessment, including anthropometric, joint laxity, and flexibility, muscle flexibility, muscle strength, and balance measurements. A total of 25 variables were examined. Participants were monitored during each season for noncontact ACL injury, as diagnosed by physicians.

Results

Noncontact ACL injuries occurred in 11 knees of 11 players (prevalence; 7.1 %). Injured players were significantly more likely to have lightweight (P = 0.049). No statistically significant between-group differences were found for any other variables. Participants with a lower hamstring to quadriceps (H/Q) ratio (P = 0.04) were more likely to sustain noncontact ACL injuries.

Conclusion

Lower H/Q ratio and lower body weight were significantly associated with new-onset noncontact ACL injury in male American football players. These findings will help develop strategies to prevent noncontact ACL injuries in male American football players.

Risk factors for hamstring strain injury in male college American football players -a preliminary prospective cohort study

BACKGROUND

Given the frequency of hamstring strain injuries (HSI) among male college American football players, several studies have attempted to determine whether certain risk factors can predict their occurrence. However, no consensus on modifiable risk factors for HSIs in male college American football players has yet been reached to prevent these injuries. This study aimed to clarify risk factors for HSI prospectively in college male American football players.

METHODS

A total of 78 male college American football players, whose positions were limited to skill positions, were medically assessed for potential risk factors of HSI. The preseason medical assessment included anthropometric measurements, joint laxity and flexibility, muscle flexibility, muscle strength, and balance ability.

RESULTS

HSI occurred in a total of 25 thighs from 25 players (32.1%). Injured players had significantly lower hamstring flexibility (p = 0.02) and hamstring to quadriceps strength ratio (H/Q) (p = 0.047) compared to uninjured players. Additionally, injured players had significantly lower general joint laxity scores, especially for the total (p = 0.04), hip (p = 0.007), and elbow (p = 0.04) scores, compared to uninjured players.

CONCLUSIONS

Lower hamstring flexibility, lower hamstring to quadriceps strength ratio, and lower general joint laxity score were identified as risk factors for HSI in male college American football players placed in skill positions. The muscle flexibility and H/Q ratio could be useful in preventing HSI in such players.

Kinematic Differences Between the Dominant and Nondominant Legs During a Single-Leg Drop Vertical Jump in Female Soccer Players

BACKGROUND

In soccer, the roles of the dominant (kicking) and nondominant (supporting) legs are different. The kinematic differences between the actions of the dominant and nondominant legs in female soccer players are not clear.

PURPOSE

To clarify the kinematic differences between dominant and nondominant legs during a single-leg drop vertical jump (DVJ) in female soccer players.

STUDY DESIGN

Controlled laboratory study.

METHODS

A total of 64 female high school and college soccer players were included in this study. Participants performed a single-leg DVJ test utilizing video motion capture with artificial intelligence during the preseason period. This study assessed the knee flexion angles, knee valgus angles, hip flexion angles, and lower leg anterior inclination angle at 3 time points (initial contact, maximum flexion of the knee, and toe-off) and compared them between the dominant and nondominant legs. These angles were calculated from motion capture data and analyzed in 3 dimensions. A paired t test was used to analyze the differences between legs, and the significance level was set at P < .05.

RESULTS

The knee valgus angle at initial contact was greater in the nondominant leg (mean ± SD, 0.8°± 5.2°) than the dominant leg (-0.9°± 4.9°) (P < .01). There were no differences between legs for any other angles at any of the time points.

CONCLUSION

The kinematics of the dominant and nondominant legs of female soccer players in a single-leg DVJ differ in knee valgus angle.

CLINICAL RELEVANCE

Leg dominance is associated with the risk of sports injuries. Kinematic differences between the dominant and nondominant legs may be a noteworthy factor in elucidating the mechanisms and risk of sports injury associated with leg dominance.

Dynamic Postural Stability Is Decreased During the Single-Leg Drop Landing Task in Male Collegiate Soccer Players With Chronic Ankle Instability

Background:

Chronic ankle instability (CAI) is commonly encountered in soccer players. The feelings of instability and anxiety caused by CAI can lead to poor performance, such as difficulty in sharp change of direction during soccer play. The single-leg drop landing (SLDL) task is often used to evaluate dynamic postural stability.

Purpose/Hypothesis:

The purpose of this study was to clarify whether dynamic stability measured during SLDL is altered in male collegiate soccer players with CAI. The hypothesis was that athletes with CAI would show poor dynamic postural stability.

Study Design:

Controlled laboratory study.

Methods:

A total of 103 male collegiate soccer players were recruited, and their limbs were classified based on the new international CAI criteria. All players performed three 5-second SLDL trials on a force plate. The main outcome measures included time to stabilization of the horizontal ground-reaction force (GRF); peak GRF in the vertical, horizontal, and sagittal directions; and trajectory length of the center of pressure during SLDL.

Results:

Data from 59 CAI limbs and 147 non-CAI limbs were collected in this study. Time to stabilization of horizontal GRF was significantly longer in the CAI limbs (P < .001), and the peak GRFs in all directions were significantly lower in the CAI limbs (vertical, P < .001; horizontal, P < .001; sagittal, P = .001). Additionally, the trajectory length of the center of pressure was significantly greater in the CAI limbs (P = .004).

Conclusion:

Soccer players with CAI had decreased dynamic postural stability that led them to land softly when performing the SLDL task. Measurement of dynamic postural stability may be useful in the evaluation of CAI.

Clinical Relevance:

Our findings may be useful for strategies of daily training or as an evaluation tool.

Sex-Based Differences in the Drop Vertical Jump as Revealed by Video Motion Capture Analysis Using Artificial Intelligence

BACKGROUND

Sex-based biomechanical differences during a drop vertical jump (DVJ) may explain the increased risk of anterior cruciate ligament injury in females. Video motion capture using artificial intelligence (VMocap) is a new method for accurate motion analysis.

PURPOSE

To use VMocap to identify sex-based differences in biomechanics during a DVJ in Asian athletes.

STUDY DESIGN

Controlled laboratory study.

METHODS

A total of 63 female and 61 male Asian soccer players volunteered for this study in 2018. Participants performed a bilateral DVJ using VMocap, and the knee valgus angle (KVA), knee flexion angle (KFA), hip flexion angle (HFA), and lower leg anterior inclination angle (LAIA) were calculated from the motion capture data. These joint angles and inclination angles were evaluated at the time of highest point of the first jump (H1), initial contact (IC), maximum knee flexion (MKF), toe-off (TO), and highest point of the second jump (H2). The unpaired t test was used to compare sex-based differences.

RESULTS

At H1, the KVA in females showed more valgus (-2.9° vs -5.4°) and the LAIA in females was greater (29.1° vs 25.7°) versus males (P < .01 for both). At IC, the KVA in females showed more valgus (-1.3° vs -3.0°) and females had a greater KFA (20.8° vs 14.3°) and LAIA (5.1° vs 0.0°) compared with males (P < .01 for all). At MKF, female KVA showed more valgus (6.2° vs -9.5°), and females had greater LAIA (36.6° vs 34.6°), smaller KFA (77.5° vs 87.5°), and smaller HFA (55.8° vs 82.0°) compared with males (P < .01 for all). At TO, female KVA showed more valgus (-0.7° vs -3.1°) and female KFA, HFA, and LAIA were greater (31.7° vs 19.2°; 19.9° vs 16.4°; and 18.2° vs 11.5°, respectively) than males (P < .01 for all). At H2, females had a greater KFA (18.6° vs 14.6°) and LAIA (13.3° vs 9.9°) than males (P < .04 for both).

CONCLUSION

Asian female soccer players showed increased KVA and LAIA, decreased KFA and HFA at MKF, and increased KFA at IC and TO compared with their male counterparts in this analysis of the DVJ.

CLINICAL RELEVANCE

Elucidation of kinematic differences between the sexes can aid in predicting injuries.

Muscle Activity Estimation at Drop Vertical Jump Landing Using Passive Muscle Mechanical Model

Among the various elements that facilitate the movement of the lower limbs, the anterior cruciate ligament (ACL) is prone to injury. An adequate joint control of the lower limb can prevent ACL injury. Balancing activities between the agonist and the antagonist muscles is vital for joint control. However, prior studies on muscle activities were limited since they could not determine passive muscle activities. In this study, we develop a muscle model considering the passive properties to analyze the movement mechanism of the ACL under heavy loads, such as those produced during jump landing. We estimated the muscle activities occurring during a drop vertical jump (DVJ) by applying to the proposed method the physiological constraint that muscle activities are constant during a short time around landing. In addition, the knee joint torque and muscle forces were calculated from the estimated muscle activities, which were thereafter compared with those obtained using the conventional method. The results revealed that this passive muscle model appropriately represented the knee joint torque at DVJ landing by decreasing the passive muscle strain and increasing the isometric maximum muscle force. Moreover, the estimated muscle activities were larger than those obtained using the conventional method, which may be caused by the co-contraction between agonist and antagonist muscles that cannot be represented by the conventional method. This muscle co-contraction estimation algorithm would estimate the muscle load under heavy loads, and applying this knowledge to training would help to prevent ACL injuries.

Earliest pulmonary vein potential guided cryoballoon ablation is associated with better clinical outcomes than conventional cryoballoon ablation: a result from two randomized clinical studies

Background

With regards to short-term outcome in atrial fibrillation (AF), the benefit of cryoballoon ablation (CBA) by pressing a balloon against the earliest pulmonary vein (PV) potential site during pulmonary vein isolation, (earliest potential [EP]-guided CBA) has been previously demonstrated.

Objective

The present study aimed to evaluate the long-term outcome of the EP-guided CBA.

Methods

This study included 136 patients from two randomized studies, who underwent CBA for paroxysmal AF for the first time. Patients were randomly assigned to the EP-guided and conventional CBA groups in each study. In the EP-guided CBA group, we pressed a balloon against the EP site when the time to isolation (TTI) after cryoapplication exceeded 60 s and 45 s in the first and second studies, respectively. The patients were followed up for 1 year after procedure. We compared the clinical outcomes between the EP-guided CBA group (68 patients) and the conventional CBA group (68 patients).

Results

No significant differences in baseline characteristics were observed between the two groups. Compared with the conventional CBA group, the EP-guided CBA group had a significantly higher success rate at TTI ≤90 s (98.5% vs. 90.0%, P&lt;0.001); lower touch-up rate and total cryoapplication; and shorter procedure time, and fluoroscopy time. The recurrence at 1-year after ablation was significantly lower in the EP-guided CBA group than in the conventional CBA group (6.0% vs. 19.4%; P=0.019).

Conclusions

The EP-guided CBA approach can facilitate the ablation procedure and achieve low recurrence at 1-year after ablation.

Funding Acknowledgement

Type of funding sources: None. Earliest potential [EP]-guided CBAThe recurrence at 1-year after ablation

Hip Abductor Muscle Strength Deficit as a Risk Factor for Inversion Ankle Sprain in Male College Soccer Players: A Prospective Cohort Study

Background:

Previous studies have attempted to determine whether certain risk factors can predict the occurrence of inversion ankle sprains in male collegiate soccer players. However, no consensus has been reached on the predictive risk factors of inversion ankle sprain in this population.

Purpose:

To identify risk factors for inversion ankle sprains among male collegiate soccer players.

Study Design:

Cohort study; Level of evidence, 2.

Methods:

Included were 145 male collegiate soccer players in Japan who were assessed during a preseason medical checkup for potential risk factors of inversion ankle sprain. The preseason assessment included anthropometric measurements, joint laxity and flexibility, muscle flexibility, muscle strength, and balance ability, with a total of 33 variables. The participants were monitored during the 2019 season for inversion ankle sprains as diagnosed by physicians.

Results:

A total of 31 inversion ankle sprains in 31 players (21.4%) occurred during the season. Only the measured isometric hip abductor strength was significantly lower in injured players as compared with uninjured players. Logistic regression analysis revealed measured hip abductor muscle strength deficit as a significant risk factor for inversion ankle sprain (odds ratio, 0.978 [95% CI, 0.976-0.999]; P = .05).

Conclusion:

Hip abductor strength deficit was a risk factor for inversion ankle sprain in the study population. This finding could be useful for the prevention of inversion ankle sprains in male collegiate soccer players.

Elucidation of brefeldin A-induced ER and Golgi stress responses in Neuro2a cells

Brefeldin A (BFA) disrupts the structure of the Golgi apparatus to trigger ER stress signaling pathways. On the other hand, treatment with BFA induces the activation of CREB3, the protein structure of which is similar to that of ATF6. In this study, we established Neuro2a cells in which three different transcription factors, namely, ATF4, ATF3 and CREB3, were deficient using the CRISPR/Cas9 approach, and we investigated the BFA-induced ER and Golgi stress response in these cells. BFA treatment rapidly induced ATF4, ATF3, Herp and GADD153 protein expression in Neuro2a cells. ATF4-deficient Neuro2a cells exhibited significantly decreased mRNA and protein expression of ATF3 and Herp but not GADD153; however, cells deficient in ATF3 exhibited minimal effects on GADD34, GADD153 and Herp expression. The cleavage of CREB3 in Neuro2a cells was triggered by BFA; however, the expression of several ER and Golgi stress-related factors was hardly influenced by the CREB3 deficiency in these Neuro2a cells. This study shows that CREB3 minimally associates with typical ER stress-inducible responses in Neuro2a cells. Therefore, identification and characterization of the downstream transcriptional targets of CREB3 is required to clarify not only Golgi stress response but also its relationship with ER stress signaling pathways.

Myocardial repolarization time, J-point to T-peak and T-peak to T-end intervals, have different heart rate dependency and autonomic nerve interference in healthy prepubertal children

OBJECTIVE

The JT interval of the myocardial repolarization time can be divided into Jpoint to T-peak interval (JTp) and T-peak to T-end interval (Tpe). It is well known that the JT interval is dependent on the heart rate, but little is known regarding heart rate dependence for JTp and Tpe. The aim of the present study was to clarify the heart rate dependence of JTp and Tpe and to elucidate the interference of autonomic nervous activity with these parameters.

METHODS

We evaluated 50 prepubertal children (mean age: 6.4 ± 0.5 years; male:female, 22:28) without heart disease. JTp, Tpe, and the preceding RR intervals were measured using 120 consecutive beats (lead CM5). First, the relationships between the RR interval and JTp and Tpe were evaluated by Pearson's correlation coefficient. Second, to evaluate autonomic interference with JTp and Tpe, the degree of coherence between RR interval variability and JTp or Tpe variability was calculated using spectral analysis.

RESULTS

Significant positive correlations were observed between the RR interval and JTp (y = 0.116x + 105.5; r = 0.594, p < 0.001) and between the RR interval and Tpe (y = 0.037x + 44.7; r = 0.432, p < 0.001). Tpe variability had a lower degree of coherence with RR interval variability (range: 0.039-0.5 Hz) than with JTp variability (0.401 [interquartile range, 0.352-0.460] vs. 0.593 [0.503-0.664], respectively; p < 0.001).

CONCLUSIONS

Tpe had lower heart rate dependence and a lower degree of autonomic nervous interference than did JTp.

Anthropometric and musculoskeletal gender differences in young soccer players

BACKGROUND

This study aimed to clarify potential gender differences across a comprehensive set of anthropometric and musculoskeletal characteristics within a young soccer player population.

METHODS

This study included 227 (121 males and 106 females with mean ages of 19.0 and 17.5 years, respectively) young elite soccer players. Anthropometric measurements were obtained. In addition, general joint laxity tests assessing the wrist, elbow, shoulder, trunk, hip, knee, and ankle were performed. Muscle flexibility tests were performed on the iliopsoas, quadriceps femoris, hamstring, gastrocnemius, and soleus muscles. Moreover, isometric knee extension and flexion strength and isometric hip abduction strength were measured. Single- and double-leg balance tests were also performed.

RESULTS

Male soccer players were taller, heavier, and had lower fat mass and percent body fat, and greater skeletal muscle mass and body minerals than female soccer players. Female soccer players had significantly greater laxity in all tests for general joint laxity. Female soccer players demonstrated significantly better hamstring and soleus flexibility than male soccer players but worse iliopsoas flexibility. Consequently, no significant differences were noticed in the quadriceps and gastrocnemius muscles between the male and female soccer players. However, female soccer players demonstrated significantly weaker knee extension and flexion and hip abduction. The hamstring- quadriceps ratio was significantly lower in female soccer players. Although no significant difference exists in the center of pressure excursion in the double-leg balance test between male and female soccer players, female soccer players displayed a significantly lower center of pressure excursion in the single-leg balance test.

CONCLUSIONS

Young male and female soccer players demonstrate significantly different anthropometric and musculoskeletal profiles.

Muscles Cooperation Analysis Using Akaike Information Criteria for Anterior Cruciate Ligament Injury Prevention

In this paper, we propose the analysis method for finding out the similarity of the muscle force patterns to mine the risk factor of the anterior cruciate ligament (ACL) injury. Akaike information criteria (AIC) under the assumption of the auto-regression model is adapted to analyze the similarities of muscle force patterns in time-series. The difference of AIC values between 2 muscles is considered to be the distance between 2 muscle force patterns and the dexterity of the maneuver is expected to be discussed. We measured drop vertical jump (DVJ) and use the data around the contact timing of whom hadn't had ACL injury experiments. The results showed that we could successfully calculate AIC distance according to the similarity of the time-series data pattern and it can be useful to discuss one's dexterity of controlling body maneuvers soon after contact timing of DVJ motion.

QT Variability Index is Correlated with Autonomic Nerve Activity in Healthy Children

The QT variability index (QTVI), which measures the instability of myocardial repolarization, is usually calculated from a single electrocardiogram (ECG) recording and can be easily applied in children. It is well known that frequency analysis of heart rate variability (HRV) can detect autonomic balance, but it is not clear whether QTVI is correlated with autonomic tone. Therefore, we evaluated the association between QTVI and HRV to elucidate whether QTVI is correlated with autonomic nerve activity. Apparently, healthy 320 children aged 0-7 years who visited Fujita Health University Hospital for heart checkup examinations were included. The RR and QT intervals of 60 continuous heart beats were measured, and the QTVI was calculated using the formula of Berger et al. Frequency analysis of HRV, including the QTVI analysis region, was conducted for 2 min and the ratio of low-frequency (LF) components to high-frequency (HF) components (LF/HF) and HF/(LF + HF) ratio was calculated as indicators of autonomic nerve activity. Then, the correlations between QTVI and these parameters were assessed. QTVI showed a significant positive correlation with LF/HF ratio (r = 0.45, p < 0.001) and negative correlation with HF/(LF + HF) ratio (r = -0.429, p < 0.001). These correlations remained after adjustment for sex and age. QTVI, which is calculated from non-invasive ECG and can detect abnormal myocardial repolarization, is significantly correlated with frequency analysis of HRV parameters. QTVI reflects autonomic nerve balance in children.

Evaluation of perinatal autonomic development in infants using the QT/RR variability ratio

OBJECTIVES

Development of the autonomic nervous system may play a role in myocardial repolarization lability in infants, but its relationship to repolarization abnormalities remains unclear. Thus, the aim of the present study was to evaluate the relationship between gestational age and ventricular repolarization lability using the variability ratio (VR).

METHODS

Infants who underwent electrocardiography at a 1-month check-up were included (n=209; 125 males). Gestational age and the following four VR parameters at 1 month of age were compared: VR-I, SDQT/SDRR; VR-II, SDQT/rMSSD; VR-III, SDQTc/SDRR; and VR-IV, SDQTc/rMSSD; where SD, QTc, and rMSSD are standard deviation, QT interval corrected using Fridericia's formula, and root mean square difference of successive RR intervals, respectively. Twenty-eight preterm infants born at <37 weeks of gestation and 181 full-term infants were included.

RESULTS

Significant correlations were observed between gestational age and VR-I, -III, and -IV (all p<0.05). All VR values were significantly higher in preterm infants compared with full-term infants (I: 0.54 vs 0.48, II: 1.15 vs 0.96, III: 0.88 vs 0.68, IV: 1.59 vs 1.39; median, all p<0.05).

CONCLUSION

VR assessed at 1 month after birth was impaired in preterm infants, suggesting immaturity of their cardiac autonomic nervous system and ventricular myocardial repolarization.

Pharmacological and Model-based Interpretation of Neuronal Dynamics Transitions during Sleep-Waking Cycle

Power spectral analysis has been applied to spontaneous single neuronal activities during the sleep-waking cycle in various regions of the cat’s central nervous system. During slow-wave sleep (SWS), the spontaneous activities of many neurons had a white noise-like power-spectral density profile in a very low frequency range (0.01-1.0 Hz) whereas, during rapid-eye-movement sleep (REMS), they showed a 1/f-like spectral pattern. This spectral transition between SWS and REMS was hypothesized to depend on the influence of serotonergic and cholinergic neuronal activity which is considered to modulate various brain functions. According to both pharmacological experiments and simulation studies with a neural network model, it was concluded that the serotonergic system may have a function to eliminate slow fluctuations in neuronal activity in wide areas, from the reticulothalamo-neocortical to the limbic systems. Consequently, simple signal processing of spontaneous neuronal activity has elucidated an important neurophysiological fact, which may lead to a principle of the basic brain function and its mechanism.

Conjunctival Displacement to the Corneal Side for Oblique-Parallel Insertion in 25-Gauge Vitrectomy

Purpose

To assess the usefulness of the method of oblique-parallel trocar insertion with conjunctival displacement to the corneal side in 25-gauge (G) transconjunctival vitrectomy.

Methods

25-G vitrectomy was performed in 77 consecutive eyes. Before making oblique-parallel trocar insertions, the conjunctiva was conventionally displaced superiorly in 35 eyes, but was displaced toward the corneal side in 42 eyes. After surgery, the distance between the scleral and conjunctival wounds was measured with calipers. The frequency of scleral wound exposure was assessed.

Results

After cannula removal at the end of surgery, inferior repositioning of the superiorly displaced conjunctiva was observed, while marked posterior repositioning of the corneal side caused displacement of the conjunctiva due to gravity. The superior displacement distances between the sclera and conjunctival wounds were 2.4±0.3 mm at the infusion port, 2.0±0.4 mm at the superior temporal port, and 1.9±0.4 mm at the superior nasal port, while the corresponding distances for corneal side displacement were 3.6±0.5, 3.5±0.5, and 2.5±0.5 mm, and were all significantly (p<0.0001) greater with corneal side displacement. The frequency of scleral wound exposure due to conjunctival damage around the cannula (infusion port) was significantly (p=0.0164) lower for corneal side displacement (0/42; 16.7%) than superior displacement (5/35; 14.3%). There was no postoperative endophthalmitis in all 77 patients studied.

Conclusions

In 25-G transconjunctival vitrectomy, using oblique-parallel trocar insertions with the conjunctiva displaced toward the corneal side results in marked posterior repositioning of the conjunctiva after cannula extraction. Corneal side conjunctival displacement is technically easy and completely covers the scleral wound. This method is expected to be effective in preventing endophthalmitis.

Relationship between QT and JT peak interval variability in prepubertal children

BACKGROUND

The QT variability index (QTVI) is a noninvasive index of repolarization lability that has been applied to subjects with cardiovascular disease. QTVI provides a ratio of normalized QT variability to normalized heart rate variability, and therefore includes an assessment of autonomic nervous activity. However, measurement of QT time is particularly difficult in children, who exhibit physiologically high heart rates compared with adults. In this study, we developed a set of standard values of J-point to Tpeak interval (JTp) for infants by age, and assessed the correlation of QTVI with the JTp variability index (JTpVI).

METHODS

Subjects included 623 infants and children (0-7 years of age) without heart disease and 57 healthy university students. All subjects were divided into three groups by age. QTVI and JTpVI were calculated based on an electrocardiogram, and age-specific standard values, a gender-specific classification, and a standard growth curve were constructed.

RESULTS

JTpVI markedly decreased in infancy and slowly decreased thereafter, reaching adult values by school age. There was also a strong correlation of JTpVI with QTVI (r = .856).

CONCLUSIONS

JTp can be used to evaluate the variability of the repolarization time in healthy infants, and may be useful for detection of early repolarization abnormalities.

Photon-counting 1.0 GHz-phase-modulation fluorometer

We have constructed an improved version of a photon-counting phase-modulation fluorometer (PC-PMF) with a maximum modulation frequency of 1.0 GHz, where a phase domain measurement is conducted with a time-correlated single-photon-counting electronics. While the basic concept of the PC-PMF has been reported previously by one of the authors, little attention has been paid to its significance, other than its weak fluorescence measurement capability. Recently, we have recognized the importance of the PC-PMF and its potential for fluorescence lifetime measurements. One important aspect of the PC-PMF is that it enables us to perform high-speed measurements that exceed the frequency bandwidths of the photomultiplier tubes that are commonly used as fluorescence detectors. We describe the advantages of the PC-PMF and demonstrate its usefulness based on fundamental performance tests. In our new version of the PC-PMF, we have used a laser diode (LD) as an excitation light source rather than the light-emitting diode that was used in the primary version. We have also designed a simple and stable LD driver to modulate the device. Additionally, we have obtained a sinusoidal histogram waveform that has multiple cycles within a time span to be measured, which is indispensable for precise phase measurements. With focus on the fluorescence intensity and the resolution time, we have compared the performance of the PC-PMF with that of a conventional PMF using the analogue light detection method.

Selective β2-adrenergic Antagonist Butoxamine Reduces Orthodontic Tooth Movement

Recently, involvement of the sympathetic nervous system in bone metabolism has attracted attention. β2-Adrenergic receptor (β2-AR) is presented on osteoblastic and osteoclastic cells. We previously demonstrated that β-AR blockers at low dose improve osteoporosis with hyperactivity of the sympathetic nervous system via β2-AR blocking, while they may have a somewhat inhibitory effect on osteoblastic activity at high doses. In this study, the effects of butoxamine (BUT), a specific β2-AR antagonist, on tooth movement were examined in spontaneously hypertensive rats (SHR) showing osteoporosis with hyperactivity of the sympathetic nervous system. We administered BUT (1 mg/kg) orally, and closed-coil springs were inserted into the upper-left first molar. After sacrifice, we calculated the amount of tooth movement and analyzed the trabecular microarchitecture and histomorphometry. The distance in the SHR control was greater than that in the Wistar-Kyoto rat group, but no significant difference was found in the SHR treated with BUT compared with the Wistar-Kyoto rat control. Analysis of bone volume per tissue volume, trabecular number, and osteoclast surface per bone surface in the alveolar bone showed clear bone loss by an increase of bone resorption in SHR. In addition, BUT treatment resulted in a recovery of alveolar bone loss. Furthermore, TH-immunoreactive nerves in the periodontal ligament were increased by tooth movement, and BUT administration decreased TH-immunoreactive nerves. These results suggest that BUT prevents alveolar bone loss and orthodontic tooth movement via β2-AR blocking.

In situ visualization of plasma cells producing antibodies reactive to Porphyromonas gingivalis in periodontitis: the application of the enzyme-labeled antigen method

Porphyromonas gingivalis is a keystone periodontal pathogen. Histologocally, the gingival tissue in periodontitis shows dense infiltration of plasma cells. However, antigens recognized by antibodies secreted from the immunocytes remain unknown. The enzyme-labeled antigen method was applied to detecting plasma cells producing P. gingivalis-specific antibodies in biopsied gingival tissue of periodontitis. N-terminally biotinylated P. gingivalis antigens, Ag53 and four gingipain domains (Arg-pro, Arg-hgp, Lys-pro and Lys-hgp) were prepared by the cell-free protein synthesis system using wheatgerm extract. With these five labeled proteins as probes, 20 lesions of periodontitis were evaluated. With the AlphaScreen method, antibodies against any one of the five P. gingivalis antigens were detected in 11 (55%) serum samples and 17 (85%) tissue extracts. Using the enzyme-labeled antigen method on paraformaldehyde-fixed frozen sections of gingival tissue, plasma cells were labeled with any one of the five antigens in 17 (94%) of 18 specimens, in which evaluable plasma cells were detected. The positivity rates in periodontitis were significantly higher than those found previously in radicular cysts (20% in sera and 33% in tissue extracts with the AlphaScreen method, and 25% with the enzyme-labeled antigen method). Our findings directly indicate that antibodies reactive to P. gingivalis are locally produced in the gingival lesions, and that inflammatory reactions against P. gingivalis are involved in periodontitis.

Overcoming tnf-alpha and cddp resistance of a human ovarian-cancer cell-line (c30) by treatment with buthionine sulfoximine in combination with tnf-alpha and or cddp

Previous studies have demonstrated that glutathione (GSH) plays an important role in a wide range of cellular functions including protection, detoxification, transport and metabolism. GSH has been implicated in tumor cell resistance to drugs and/or cytotoxic factors. Buthionine sulfoximine (BSO), a specific inhibitor of gamma-glutamylcysteine synthetase, depletes intracellular GSH and thus could reverse resistance. The present study investigated the effect of BSO used in combination with tumor necrosis factor-alpha (TNF-alpha) or cisdiamminedichloroplatinum (II) (CDDP) on cytotoxicity of a TNF-alpha and CDDP resistant human ovarian cancer cell line (C30). Cytotoxicity was monitored by the MTT assay. Treatment of C30 cells with BSO and CDDP or BSO and TNF-alpha resulted in overcoming resistance and a synergistic cytotoxic effect was obtained. Pretreatment of the tumor cells by either agent for 4 h and wash and followed by the addition of the second agent for 20 h resulted in the same cytotoxicity as observed in the presence of the two agents. Furthermore, combination treatment with BSO, CDDP and TNF-alpha further augmented the synergistic cytotoxic activity achieved by two agents against C30 cells. The protective effect of GSH was shown for TNF-alpha but not for CDDP as treatment of C30 cells with TNF-alpha in combination with GSH or N-acetyl-cysteine (NAC) reduced the cytotoxic effect of TNF-alpha. One mechanism of resistance to TNF-alpha in tumor cells is through the induction of TNF-alpha mRNA and/or protein. The C30 cells did not constitutively express TNF-alpha mRNA, however, treatment of C30 cells with TNF-alpha upregulated the expression of TNF-alpha mRNA. When BSO was used in combination with TNF-alpha, the level of TNF-alpha mRNA induced by TNF-alpha was markedly reduced. Further, incubation of C30 cells with TNF-alpha in conjunction with GSH or NAC also downregulated the expression of TNF-alpha mRNA induced by TNF-alpha. These findings demonstrate that treatment with BSO in combination with TNF-alpha or CDDP can overcome the resistance of C30 tumor cells to TNF-alpha and CDDP. The depletion of intracellular GSH and downregulation of TNF-alpha mRNA by BSO may play a role in the enhanced cytotoxicity seen with the combination of BSO and TNF-alpha. The synergistic effect obtained with a CDDP selected resistant ovarian cancer cell line suggests that treatment with BSO in conjunction with either TNF-alpha or CDDP, or TNF-alpha and CDDP may have a clinical application in the therapy of TNF-alpha and/or CDDP resistant ovarian tumors'

Antibacterial activity of adriamycin against bacillus Calmette-Guerin

Although intravesical instillation of bacillus Calmette-Guerin (BCG) or adriamycin (ADR) is an established and effective therapy for superficial bladder cancer, the current major problems are BCG-resistant and ADR-resistant bladder cancer and recurrence after the instillation therapy. Combination therapy with BCG and ADR might overcome the drug-resistance of bladder cancer. However, before combined used of BCG and ADR, it should be clarified whether ADR has bactericidal and bacteriostatic effects on BCG or not, since only alive BCG has a potential antitumor effect. In the current study, the in vitro antibacterial activity of ADR was assessed on BCG by the standard serial two-fold dilution method. When BCG was treated with ADR at 0.13-125 mu g/ml for two hours, ADR had no effect on the viability and the growth of BCG. However, ADR at 250-1,000 mu g/ml had a bactericidal effect on BCG. Epirubicin (EPI) at 0.13-15.6 mu g/ml did not affect the viability and the growth of BCG, however, EPI at 31.3-1,000 mu g/ml had a bactericidal activity. Pirarubicin (THP) at 125-1,000 mu g/ml also had a bactericidal activity. The minimal inhibitory concentrations of ADR, EPI and THP were 250, 250 and 125 mu g/ml, respectively. This study demonstrates that ADR at high concentrations had bactericidal and bacteriostatic effects on BCG. These findings suggest that combination treatment with BCG and low dose ADR could be used and overcome the resistance of bladder cancer to BCG and ADR. The possible clinical implications of the combined use of BCG and ADR are discussed.

Low-temperature synthesis of single-walled carbon nanotubes by alcohol gas source growth in high vacuum

Carbon nanotube (CNT) growth was carried out on SiO2/Si substrates with a Co catalyst using an alcohol gas source method in an ultra-high vacuum chamber. The resulting CNTs were characterized by scanning electron microscopy (SEM), Raman spectroscopy and transmission electron microscopy (TEM). Reducing the ethanol pressure decreased the optimum growth temperature for maximum yield, enabling single-walled carbon nanotube (SWNT) growth at 400 degrees C. By employing an Al2Ox buffer layer, SWNT yield increased several times, even at 400 degrees C. Under TEM observation, the Co particle size on the Al2Ox layers did not show a significant dependence on the growth temperature between 400 and 700 degrees C. Raman and TEM results confirmed activation of Co particles with larger diameter (>1 nm) by the Al2Ox buffer layer.

Autoerythrocyte sensitization syndrome with vertigo and hemilateral auditory impairment

Autoerythrocyte sensitization syndrome (AES) is characterized by recurrent, painful purpura or ecchymosis. Testing for the reappearance of lesions after injection of the patient's own erythrocytes is usually useful for the diagnosis of AES, but the significance of this test is still controversial. As the lesions often appear in patients with psychiatric disorders, mental factors such as depression and stress are considered to be involved in the occurrence and exacerbation of AES. We report a 28-year-old woman who presented recurrent episodes of painful purpura with vertigo and hemilateral auditory impairment after difficulties at her workplace. After the diagnosis of AES, she was referred for psychiatric counselling, after which the symptoms disappeared. These findings suggest that treatment for psychological disorders is important in patients with AES.

Significance of the expression of thymidylate synthase in prostate cancer

e16163

Background: Thymidylate synthase ( TS ) is an important enzyme in de novo DNA synthesis pathway. 5-Fluorouracil ( 5-FU ), an anticancer chemotherapeutic agent used clinically against a variety of cancers including prostate cancer, inhibits DNA synthesis by binding TS. In the present study, we examined TS expression in prostate cancer and investigated its prognostic significance. Methods: Fifty-two prostate cancer tissue specimens were obtained from patients who underwent radical prostatectomy for prostate cancer without neoadjuvant hormonal therapy. Forty-eight prostate cancer tissue specimens were also obtained from patients who underwent radical prostatectomy for prostate cancer with neoadjuvant hormonal therapy. We examined prostate cancer tissue and normal prostate tissue for TS expression by immunohistochemistry. Results: TS was expressed at higher levels in prostate cancer without neoadjuvant hormonal therapy, compared with normal prostate.TS expression in stage T3 prostate cancer was higher than that in stage T2 prostate cancer. In addition, the level of TS expression in Gleason score 7 or greater prostate cancer was higher than that in Gleason score less than 7 prostate cancer. Patients with prostate cancer with negative TS expression without neoadjuvant hormonal therapy had a longer postoperative recurrence-free rate than those with positive expression in the 5 year follow-up. In addition, patients with Gleason score less than 7 prostate cancer with negative TS expression had a much longer postoperative recurrence-free rate than those with positive expression in the 5-year follow-up. TS expression was significantly decreased in prostate cancer patients who received neoadjuvant hormonal therapy, especially stage T2 prostate cancer patients. Conclusions: The current study has demonstrated for the first time that TS expression may be a prognostic parameterr for prostate cancer patients undergoing radical prostatectomy.

No significant financial relationships to disclose.

Antineutrophil cytoplasmic antibody-associated vasculitis with oculomotor nerve palsy

We report a patient with antineutrophil cytoplasmic antibody-associated vasculitis with oculomotor nerve palsy. The patient presented with a high fever, diplopia, blepharoptosis and impairment of ocular movement of the left eye except for lateral gaze. Multiple erythematous and livedoid lesions were observed on the forehead, both cheeks and both legs. Laboratory examination showed positive results for myeloperoxidase antineutrophil cytoplasmic antibodies. Skin biopsy revealed leucocytoclastic vasculitis of the small arteries in the lower dermis. The patient was successfully treated with systemic corticosteroids.

Can we develop biomarkers that predict response of cancer patients to immunotherapy?

PRIMARY OBJECTIVE

The primary objective is to delineate the potential utility of cancer biomarkers that correlate and predict response to immunotherapy in cancer patients who are refractory to conventional therapeutics. Unlike significant development of biomarkers that predict response to chemotherapy, very few biomarkers have been developed to predict the response to immunotherapy.

MAIN OUTCOMES AND RESULTS

This article describes briefly the importance of characterizing and validating biomarkers for immunotherapy. A few examples have been provided, such as the transcription factor NF-kappaB, the transcription repressor Yin-Yang 1 (YY1), the pro-apoptotic gene product (Smac/DIABLO) and the circulating Fas and Fas ligand. These biomarkers have been determined to be of prognostic significance in different cancers.

CONCLUSIONS

Immunotherapy is considered as an alternative therapy in the treatment of cancer patients who are refractory to chemotherapy/radiation/hormonal therapies. Cross-resistance to apoptosis develops between cancer cells that are resistant to conventional therapeutics and immunotherapy. Therefore, it is important to develop biomarkers that will determine patient response to immunotherapy.

Severe hypoglycaemia in a person with insulin autoimmune syndrome accompanied by insulin receptor anomaly type B

AIMS

A rare case of the insulin autoimmune syndrome (IAS) accompanied by insulin receptor anomaly is reported.

METHODS

Antibodies to insulin and insulin receptor were determined in the patient with severe hypoglycaemia before and after the treatment with prednisolone.

RESULTS

Titers of antibody to insulin and insulin receptors were 73.0% and 41.5%, respectively. Drug-induced lymphocyte stimulation tests were all negative for the suspicious drugs. Her HLA-DR was DRB1*0403/04051. Following steroid therapy, the formation of antibodies was suppressed and alleviated her symptoms. Scatchard analysis yielded findings specific to polyclonal antibodies.

CONCLUSIONS

The changes in autoantibodies resulted in alleviation of the hypoglycemic symptoms as a result of steroid therapy.

25-Gauge peripheral iridectomy during vitrectomy

PURPOSE

To report peripheral iridectomy using a 25-gauge vitreous cutter in a 42-year-old man with pupillary block due to adhesion of the internal iris surface to the continuous circular capsulorhexis.

METHODS

A corneal opening was made at 10 o'clock during vitrectomy. A 25-gauge vitreous cutter was inserted into the anterior chamber with the port facing downward, and peripheral iridectomy at the 12 o'clock position was performed. The vitreous cutter was set at a cutting speed of 2500 cpm and the aspiration pressure at 600 mmHg.

RESULTS

A 25-gauge vitreous cutter with a fine shaft could easily be inserted into the peripheral anterior chamber, and there was no contact with the corneal endothelium even when the anterior chamber became shallow in association with iridectomy. In this patient, pupillary block resolved with peripheral iridectomy, and ocular pressure was also controlled.

CONCLUSIONS

25-gauge peripheral iridectomy is a simple technique that permits iridectomy of appropriate size at any desirable location.

Effect of low-intensity back exercise on quality of life and back extensor strength in patients with osteoporosis: a randomized controlled trial

Randomized controlled study in 80 postmenopausal women with osteoporosis was conducted to investigate the effect of a home-based, simple, low-intensity exercise. Low-intensity back-strengthening exercise was effective in improving the quality of life and back extensor strength.

INTRODUCTION AND HYPOTHESIS

Back-strengthening exercise is effective in increasing back extensor strength and decreasing risk of vertebral fractures. We hypothesized that a home-based, simple, low-intensity exercise could enhance back extensor strength and improve the quality of life and/or spinal range of motion in postmenopausal women in a short-term follow-up.

METHODS

Eighty postmenopausal women with osteoporosis were randomly assigned to a control group (n = 38) or an exercise group (n = 42). Subjects were instructed to lift their upper trunk from a prone position antigravity and maintain the neutral position. Isometric back extensor strength, spinal range of motion, and scores for quality of life were evaluated at baseline and 4 months.

RESULTS

Back extensor strength significantly increased both in the exercise group (26%) and in the control group (11%). Scores for quality of life increased in the exercise group (7%), whereas it remained unchanged in the control group (0%). There was a significant difference in quality of life score between the groups (p = 0.012).

CONCLUSIONS

Low-intensity back-strengthening exercise was effective in improving the quality of life and back extensor strength in patients with osteoporosis.

Enhanced orotate phosphoribosyltransferase activity in renal cell carcinoma and its prognostic significance

15590

Background: 5-Fluorouracil ( 5-FU ) is an anticancer agent clinically used against various cancers including renal cell carcinoma ( RCC ). 5-FU is a prodrug and orotate phosphoribosyltransferase ( OPRT ) is the principal enzyme which directly converts 5-FU to an active anticancer metabolite, 5-fluoro-2’-deoxyuridine 5’-monophosphate. Furthermore, OPRT is the key enzyme in the de novo DNA and RNA synthetic process, which converts orotic acid to orotidine 5’-phosphate. Little is known about the significance of OPRT in a variety of cancers including RCC. We investigated OPRT activity in 83 RCC and evaluated the association between OPRT activity and the stage/grade of RCC. The relationship between OPRT activity in RCC cells and their sensitivity to 5-FU was also examined. Methods: OPRT activity in non-fixed fresh frozen RCC and normal kidney were determined enzymatically by the 5-FU phosphorylation assay. The sensitivity of RCC cells to 5-FU was assessed by the microculture tetrazolium dye assay. Results: OPRT activity was approximately 8.5-fold higher in RCC compared to normal kidney. OPRT activity in T3/4 RCC was 3-fold higher than that in T1/2 RCC. OPRT activity in M1 RCC was 2.5-fold higher than that in M0 RCC. In addition, OPRT activity in Stage III/IV RCC was 3-fold higher than that in Stage I/II RCC. The level of OPRT activity in Grade 3 RCC was 3-fold higher than that in Grade 1/2 cancer. Patients with RCC with low OPRT activity had a longer postoperative disease-specific survival than those with high activity in the 5-year follow-up. OPRT activity in RCC cells positively correlated with their sensitivity to 5-FU. Conclusions: The present study has demonstrated that OPRT activity in RCC was higher than that in normal kidney, and that OPRT activity positively correlated with the stage/grade of RCC. Moreover, higher OPRT activity in RCC predicted worse prognosis and higher sensitivity to 5-FU. These results suggest that OPRT activity may be used as both a prognostic parameter and a predictive indicator for 5-FU efficacy in RCC.

No significant financial relationships to disclose.

Restless legs syndrome in hemodialysis patients: health-related quality of life and laboratory data analysis

AIMS

To compare clinical data, sleep quality and health-related quality of life (HRQOL) with and without RLS in HD patients.

MATERIALS AND METHODS

The international RLS study group diagnosis questionnaire was completed by 228 HD patients. The Pittsburg Sleep Quality Index (PSQI) for the evaluation of sleep quality and the Kidney Disease Quality of Life (KDQOL-SF) for the analysis of HRQOL were also used.

RESULTS

53 (23%) patients were diagnosed as RLS. Age and age at the initiation of HD were significantly younger in the RLS group. Serum calcium concentration (Ca) was significantly higher in the RLS group. Sleep quality evaluated by PSQI was significantly lower in the RLS group. In SF-36 domains of KDQOL-SF, bodily pain, general health perceptions, vitality, role functioning emotional, mental health and mental component score were significantly lower in the RLS group. In kidney targeted scales of KDQOL-SF, symptoms/problems, burden of kidney disease, cognitive function, quality of social interaction, sleep and patient satisfaction were significantly lower in the RLS group.

CONCLUSION

High Ca was possibly connected to the pathophysiology of RLS which impaired sleep quality as well as HRQOL including mental health and many kidney disease related scales.