Intractable ventricular tachycardia treated with massive countershock and large doses· of procainamide

Ventricular tachycardia complicating myocardial infarction is a dangerous condition requiring urgent therapy. A case report describes the most challenging therapeutic problem of ventricular tachycardia which we have encountered over the past five years in the Coronary Intensive Care Unit.S. Afr. Med. J.  48, 305 (1974)

The biology of Alestes imberi Peters (Pisces:Characidae) in Lake McIlwaine, Rhodesia

The population of Alestes imberi in Lake Mcllwaine increased greatly in late 1974, but the species is of little economic importance in the lake. The breeding season is short and coincides with the main river floods. Females are larger than males and fecundity is extremely high. Like other Alestes species it is a very versatile feeder, and utilizes mainly insect alates from April to November, and chironomid larvae and pupae from December to March. It is able to takeadvantage of periodic insect emergences and to utilize some plant material. Zooplankton and fish are not important food items. Condition factors appear to be related to spawning. Growth rates could only be assessed indirectly but appear to be more rapid in Lake Mcllwaine than in Lake Kariba

An ultrasonic method for measuring fluid penetration rate into threaded contacts

Various methods have been employed to study the efficacy of multipurpose penetrating oils but these techniques do not investigate the rate which these oils penetrate surfaces. This paper outlines a novel, non-invasive ultrasonic method that provides a direct means of mapping fluid penetration in threaded systems. An apparatus with piezoelectric elements was developed to pulse ultrasonic waves into a nut specimen where the waves reflected from the threaded interface. The reflected signal amplitude shifted as fluid penetrated the thread, allowing the fluid to be mapped to provide a measure of ingress rate. The results for three fluid samples are presented. Measurements suggest the fluid tracks helically down the unloaded side of the thread and radially into the loaded thread surfaces

Ultrasonic monitoring of insulated block joints

Insulated block joints are essential components used in railway tracks, to separate them into circuits used for train detection and signalling. However, they also represent a week point in the track system, and have a finite life. Condition monitoring of these components in order to plan preventative maintenance is currently labour intensive, and can lead to significant costs for the rail operator. In this study, IBJ’s were fatigued via shear load, whilst being condition monitored for degradation using a normally incident ultrasonic technique. Tests were also initially performed on lap-joints and shear specimens to further understand the response of the ultrasonic signal to failure of the adhesive layer under controlled conditions. Dynamic reflection coefficients as well as applied load were recorded in all tests, and results compared to failure zones on the specimens. The results showed that the ultrasonic technique was able to determine the on-set of failure and de-bonding of the adhesive layer, as well as degradation and wear. The technique was also able to highlight differences in performance between two different liners, pultruded glass reinforced polyester resin and a flexible glass fibre sheet, with the latter showing improved resistance. The outcomes of this study have highlighted the viability of condition monitoring IBJs using an ultrasonic approach, and have provided a basis for a future field trial

Cost of Outpatient Arthroscopic Anterior Cruciate Ligament Reconstruction Among Commercially Insured Patients in the United States, 2005-2013

Background: Despite the significance of anterior cruciate ligament (ACL) injuries, these conditions have been under-researched from a population-level perspective. It is important to determine the economic effect of these injuries in order to document the public health burden in the United States. Purpose: To describe the cost of outpatient arthroscopic ACL reconstruction and health care utilization among commercially insured beneficiaries in the United States. Study Design: Economic and decision analysis; Level of evidence, 3. Methods: The study used the Truven Health Analytics MarketScan Commercial Claims and Encounters database, an administrative claims database that contains a large sample (approximately 148 million) of privately insured individuals aged <65 years and enrolled in employer-sponsored plans. All claims with Current Procedural Terminology (CPT) code 29888 (arthroscopically aided ACL reconstruction or augmentation) from 2005 to 2013 were included. “Immediate procedure” cost was computed assuming a 3-day window of care centered on date of surgery. “Total health care utilization” cost was computed using a 9-month window of care (3 months preoperative and 6 months postoperative). Results: There were 229,446 outpatient arthroscopic ACL reconstructions performed over the 9-year study period. Median immediate procedure cost was $9399.49. Median total health care utilization cost was$13,403.38. Patients who underwent concomitant collateral ligament (medial [MCL], lateral [LCL]) repair or reconstruction had the highest costs for both immediate procedure ($12,473.24) and health care utilization ($17,006.34). For patients who had more than 1 reconstruction captured in the database, total health care utilization costs were higher for the second procedure than the first procedure ($16,238.43 vs$15,000.36), despite the fact that immediate procedure costs were lower for second procedures ($8685.73 vs$9445.26). Conclusion: These results provide a foundation for understanding the public health burden of ACL injuries in the United States. Our findings suggest that further research on the prevention and treatment of ACL injuries is necessary to reduce this burden

Trends in Incidence of ACL Reconstruction and Concomitant Procedures Among Commercially Insured Individuals in the United States, 2002-2014

Background: Few population-based descriptive studies on the incidence of anterior cruciate ligament (ACL) reconstruction and concomitant pathology exist. Hypothesis: Incidence of ACL reconstruction has increased from 2002 to 2014. Study Design: Descriptive clinical epidemiology study. Level of Evidence: Level 3. Methods: The Truven Health Analytics MarketScan Commercial Claims and Encounters database, which contains insurance enrollment and health care utilization data for approximately 158 million privately insured individuals younger than 65 years, was used to obtain records of ACL reconstructions performed between 2002 and 2014 and any concomitant pathology using Current Procedures Terminology (CPT) and International Classification of Diseases, Ninth Revision (ICD-9) codes. The denominator population was defined as the total number of person-years (PYs) for all individuals in the database. Annual rates were computed overall and stratified by age, sex, and concomitant procedure. Results: There were 283,810 ACL reconstructions and 385,384,623 PYs from 2002 to 2014. The overall rate of ACL reconstruction increased 22%, from 61.4 per 100,000 PYs in 2002 to 74.6 per 100,000 PYs in 2014. Rates of isolated ACL reconstruction were relatively stable over the study period. However, among children and adolescents, rates of both isolated ACL reconstruction and ACL reconstruction with concomitant meniscal surgery increased substantially. Adolescents aged 13 to 17 years had the highest absolute rates of ACL reconstruction, and their rates increased dramatically over the 13-year study period (isolated, +37%; ACL + meniscal repair, +107%; ACL + meniscectomy, +63%). Rates of isolated ACL reconstruction were similar for males and females (26.1 vs 25.6 per 100,000 PYs, respectively, in 2014), but males had higher rates of ACL reconstruction with concomitant meniscal surgery than females. Conclusion: Incidence rates of isolated ACL reconstruction and rates of concomitant meniscal surgery have increased, particularly among children and adolescents. Clinical Relevance: A renewed focus on adoption of injury prevention programs is needed to mitigate these trends. In addition, more research is needed on long-term patient outcomes and postoperative health care utilization after ACL reconstruction, with a focus on understanding the sex-based disparity in concomitant meniscal surgery

Reaction Time and Joint Kinematics During Functional Movement in Recently Concussed Individuals

Objective: To compare movement reaction time and joint kinematics between athletes with recent concussion and matched control recreational athletes during 3 functional tasks. Design: Cross-sectional. Setting: Laboratory. Participants: College-aged recreational athletes (N=30) comprising 2 groups (15 participants each): (1) recent concussion group (median time since concussion, 126d; range, 28–432d) and (2) age- and sex-matched control group with no recent concussions. Interventions: We investigated movement reaction time and joint kinematics during 3 tasks: (1) jump landing, (2) anticipated cut, and (3) unanticipated cut. Main Outcome Measures: Reaction time and reaction time cost (jump landing reaction time–cut reaction time/jump landing reaction time×100%), along with trunk, hip, and knee joint angles in the sagittal and frontal planes at initial ground contact. Results: There were no reaction time between-group differences, but the control group displayed improved reaction time cost (10.7%) during anticipated cutting compared with the concussed group (0.8%; P=.030). The control group displayed less trunk flexion than the concussed group during the nondominant anticipated cut (5.1° difference; P=.022). There were no other kinematic between-group differences (P≥.079). Conclusions: We observed subtle reaction time and kinematic differences between individuals with recent concussion and those without concussion more than a month after return to activity after concussion. The clinical interpretation of these findings remains unclear, but may have future implications for postconcussion management and rehabilitation

Longitudinal Analysis of Inter-Limb Coordination Before and After Anterior Cruciate Ligament Injury: The JUMP-ACL Study

Purpose: Inter-limb coordination may provide insight into why patients with anterior cruciate ligament reconstructive surgery (ACLR) have an increased risk for future injury and osteoarthritis. The purpose of this study was to compare inter-limb coordination prior-to anterior cruciate ligament (ACL) injury and following ACLR. Methods: Unilateral lower extremity biomechanics during a double-leg jump landing were collected prior-to ACL injury (baseline) and after ACLR, rehabilitation, and return to physical activity (follow-up). Sixty-nine participants were included in this analysis: 31 participants suffered an ACL injury since baseline: 12 injured the leg tested at baseline [ACLR-injured leg (ACLR-INJ), n = 12] and 19 injured the leg that was not tested at baseline [ACLR-uninjured leg (ACLR-UNINJ) n = 19]; 38 participants served as matched controls. Inter-limb coordination—calculated as the mean coupling angle—between the hip and knee were measured in the respective leg of each defined group and compared amongst groups at baseline and follow-up. Results: We observed no significant change in sagittal or frontal plane inter-limb coordination amongst groups or across time (P > 0.05). A significant decrease in inter-limb coordination in the transverse plane from baseline and follow-up was observed but limited to the ACLR-INJ group (P = 0.016). Conclusion: The primary finding of this study is that inter-limb coordination between the hip and knee in the sagittal and frontal plane is unchanged by ACL injury and ACLR. This may help explain previous observations of changes in kinematics at both the hip and knee in this population. Our observation of alterations in the transverse plane should be interpreted with caution, but may provide additional evidence for potential mechanisms that lead to the development of osteoarthritis in ACLR patients

Functional balance assessment in recreational college-aged individuals with a concussion history

Objectives: Despite evidence for increased musculoskeletal injury after concussion recovery, there is a lack of dynamic balance assessments that could inform management and research into this increased injury risk post-concussion. Our purpose was to identify tandem gait dynamic balance deficits in recreational athletes with a concussion history within the past 18-months compared to matched controls. Design: Cross-sectional, laboratory study. Methods: Fifteen participants with a concussion history (age: 19.7 ± 0.9 years; 9 females; median time since concussion 126 days, range 28–432 days), and 15 matched controls (19.7 ± 1.6 years; 9 females) with no recent concussion history participated. We measured center-of-pressure (COP) outcomes (velocity, path length, speed, dual-task cost) under 4 tandem gait conditions: (1) tandem gait, (2) tandem gait, eyes closed, (3) tandem gait, eyes open, cognitive distraction, and (4) tandem gait, eyes closed, cognitive distraction. Results: The concussion history group demonstrated slower tandem gait velocity compared to the control group (4.0 cm/s difference), thus velocity was used as a covariate when analyzing COP path length and speed. The concussion history group (23.5%) demonstrated greater COP speed dual-task cost than the control group (16.3%) during the eyes closed dual-task condition. No other comparisons were statistically significant. Conclusions: There may be subtle dynamic balance differences during tandem gait that are detectable after return-to-activity following concussion, but the clinical significance of these findings is unclear. Longitudinal investigations should identify acute movement deficits in varying visual and cognitive scenarios after concussion in comparison with recovery on traditional concussion assessment tools while also recording musculoskeletal injury outcomes