30-second Duration Research Articles

Redefining the blanking period after pulsed-field ablation in patients with atrial fibrillation

BackgroundRecurrence during the 3-month blanking period after radiofrequency ablation of atrial fibrillation (AF) is typically not considered as a predictor for late recurrence. ObjectiveWe investigated the significance of early recurrence as a risk factor for late recurrence in patients with AF receiving pulsed-field ablation (PFA). MethodsConsecutive patients undergoing PFA were prospectively followed up for 1 year. All patients received isolation of pulmonary veins. Additional ablation procedures were performed per operator’s discretion. After the procedure, all remained on their previously ineffective antiarrhythmic drugs (AADs) during the 2-month blanking period after which the AADs were discontinued. Early recurrence was defined as atrial arrhythmia of >30-second duration during the 3-month blanking period, and any recurrence beyond 3 months was considered as late recurrence. ResultsA total of 337 patients undergoing PFA for AF were included. Early recurrence was recorded in 53 patients (15.7%): 10 in the first month, 12 in the second month, and 31 in the third month. Of the 10 patients having recurrence during the first month, 7 (70%) remained in sinus rhythm after cardioversion whereas 3 (30%) underwent a redo procedure because of late recurrence. At 1 year, all patients with recurrence in the second and third months experienced late recurrence; among these patients, 10 (83.3%) of 12 and 27 (87%) of 31 underwent a redo procedure and the remaining 6 patients were in sinus rhythm on AADs. ConclusionIn this consecutive series of patients with AF, early recurrence in the second or third month after the PFA procedure was associated with a high risk of late recurrence. Thus, blanking period could be redefined as 1 month after PFA.

Hyperparameter Optimization of CNN Classifier for Music Genre Classification

Playing music through a digital platform that has a large database of songs requires automated classification of music genres, highlighting the need to develop a model for music genre classification that is more efficient and accurate. This study evaluated the hyperparameters in the music genre classification process using CNN in the GTZAN dataset with 30-second duration data optimized using MFCC feature extraction. The model that is formed with a time of 3 (three) seconds classifies music genres in the first 3 seconds of music. This model has a high potential for error because the first 3 seconds of initial music are varied and cannot be used as a benchmark in determining music genres. This study performed hyperparameters on batch size, epoch, and split data set variables with various scenarios. The highest precision result was obtained at 72% with a data split of 85%:15%, 32 batch sizes, and 500 epochs.

Value of genetic testing in the diagnosis and risk stratification of arrhythmogenic right ventricular cardiomyopathy.

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is characterized by risk of malignant ventricular arrhythmia (VA). ARVC is diagnosed using an array of clinical tests in the consensus-based Task Force Criteria (TFC), one of which is genetic testing. The purpose of this study was to investigate the value of genetic testing in diagnosing ARVC and its relation to the occurrence of first malignant VA. A multicenter cohort of patients with ARVC was scored using the revised 2010 TFC with and without genetic criterion, analyzing any resulting loss or delay of diagnosis. Malignant VA was defined as sustained VA (≥30-second duration at ≥100 beats/min or requiring intervention). We included 402 subjects (221 [55%] male; 216 [54%] proband; 40 [27-51] years old at presentation) who were diagnosed with definite ARVC. A total of 232 subjects (58%) fulfilled genetic testing criteria. Removing the genetic criterion caused loss of diagnosis in 18 patients (4%) (11 of 216 probands [5%] and 7 of 186 relatives [4%]) and delay of diagnosis by ≥30 days in 22 patients (5%) (21 of 216 probands [10%] and 1 of 186 relative [0.5%]). A first malignant VA occurred in no patients who lost diagnosis and in 3 patients (3 of 216 probands [1%] and no relatives) during their diagnosis delay, none fatal. Time-to-event analysis showed no significant difference in time from diagnosis to malignant VA between pathogenic variant carriers and noncarriers. Disregarding the genetic criterion of the TFC caused loss or delay of diagnosis in 10% of patients with ARVC (40 of 402). Malignant VA occurred in 1% of cases with lost or delayed diagnosis (3 of 402), none fatal.

Application of recurrence plot analysis to characterise whole chamber propagation of atrial fibrillation

Abstract Funding Acknowledgements Type of funding sources: Public hospital(s). Main funding source(s): Oxford Biomedical Research Centre Introduction Non-contact charge density mapping allows visualisation of whole chamber propagation during atrial fibrillation (AF). The identification of regions with repetitive or, conversely, more complex patterns of wavefront propagation may provide clues to mechanisms responsible for AF maintenance and lead to improved outcomes from catheter ablation. Our novel mapping approach based on signal recurrence plots has never been applied to whole chamber, bi-atrial recording of atrial fibrillation. Purpose To apply recurrence analysis to characterise whole chamber bi-atrial AF propagation. Methods Non-contact dipole signals from left and right atrial maps were obtained during simultaneous bi-atrial charge density mapping of AF. Signals were converted to phase and mean phase coherence calculated for the generation of recurrence distance matrices for the whole chamber and each anatomical region (6x LA and 4x RA) over the 30-second recording duration, where a value of 1 (purple, see figure panel A) represents uniform repetitive conduction, and 0 (red), irregular, non-repetitive activity. Whole chamber and regional mean recurrence values were calculated and correlated with the frequency of wavefronts of localised irregular activation patterns. Results Maps were obtained prior to ablation in 21 patients (5 paroxysmal (pAF), 16 persistent AF (persAF)) undergoing de-novo catheter ablation procedures. Whole chamber recurrence was higher in patients with pAF (0.40 ± 0.08) than persAF (0.34 ± 0.05), p < 0.0005. There was an inverse correlation between regional recurrence values and the number of localised irregular activations detected (-0.7021, p < 0.0005, figure panel B) with the lateral LA and anterior RA demonstrating the highest recurrence values in each chamber (figure panel C). Conclusion Use of recurrence distance matrices characterises global AF propagation phenotypes. Regional values are inversely correlated with the frequency of localised irregular activation patterns identified demonstrating an anatomic dependence in the level of AF propagation complexity, greatest in the anterior LA and septal RA. Comparison of strategies targeting regions with maximal vs. minimal values during catheter ablation may define an optimal approach to treatment of persistent AF. Abstract Figure. Recurrence abstract figure

Lead in drinking water

Background: Lead is a systemic toxin that affects multiple organs and impairs physical and mental development. Although lead is ubiquitous in the environment, majority of exposures to lead is through drinking water. Lead-based plumbing components are the primary reason. Flushing is a lead reduction technique commonly used to reduce lead in drinking water, but the efficacy of the technique has been questioned. The purpose of this research project was to determine if there were significant levels of lead found in the drinking water of 12 buildings (sites) owned and operated by a Health Authority before and after 30-second flush and to determine if flushing is an effective measure to reduce lead concentrations.Materials and Methods: Lead in drinking water data was provided by Dr. Tom Kosatsky in an Excel spreadsheet. The data contained 184 pre-flush (≥ 8-hour stagnation period) samples paired to 184 post-flush (30-second duration) samples collected at locations within the 12 different sites. The sites were labelled A to L due to confidentiality. This data was then exported to NCSS, and statistical analysis in the forms of a two tailed t-test, one tailed one sample t-test, and repeated measures ANOVA was performed to determine if a statistically significant relationship between flushing and reduced lead concentrations exists.Results: Out of 368 samples, 28% of stagnation samples contained lead concentrations greater than the MAC (n = 103) whereas, 9% of post 30-second flush samples contained lead concentration greater than the MAC (n = 33). Lead concentrations in the drinking water samples after flushing were significantly reduced below the MAC (p = 0.00000). However, lead concentrations from samples collected at sites A, C, and G were equal to or greater than the MAC. Statistical analysis failed to reject the null hypothesis that post-flush lead concentrations for samples collected at sites A, C, and G is greater to or equal to the MAC (A: p = 0.22708, C: p = 0.06866, and G: p = 0.70589).Conclusion: Flushing is an effective measure in reducing lead concentrations at the tap to safe levels. However, the effectiveness of flushing and flushing duration is dependent on numerous factors such as the stagnation period, amount of lead-based plumbing supplying the drinking water and building size. Longer stagnation periods, increased lead-based plumbing, and large buildings all require longer flushing times to reduce lead concentrations to below 0.005 mg/L. The results of this can study can aid governments in developing polices that will eliminate existing lead infrastructure in British Columbia and Canada. Flushing is not a long-term solution in reducing lead concentrations at the tap to below 0.005 mg/L.

B lymphocytes contribute to indirect pathway T cell sensitization via acquisition of extracellular vesicles.

B cells have been implicated in transplant rejection via antibody-mediated mechanisms and more recently by presenting donor antigens to T cells. We have shown in patients with chronic antibody-mediated rejection that B cells control the indirect T cell alloresponses. To understand more about the role of B cells as antigen-presenting cells for CD4+ T cell with indirect allospecificity, B cells were depleted in C57BL/6 mice, using an anti-CD20 antibody, prior to receiving MHC class I-mismatched (Kd ) skin. The absence of B cells at the time of transplantation prolonged skin graft survival. To study the mechanisms behind this observation, T cells with indirect allospecificity were transferred in mice receiving a Kd skin transplant. T cell proliferation was markedly inhibited in the absence of recipient B cells, suggesting that B cells contribute to indirect pathway sensitization. Furthermore, we have shown that a possible way in which B cells present alloantigens is via acquisition of MHC-peptide complexes. Finally, we demonstrate that the addition of B cell depletion to the transfer of regulatory T cells (Tregs) with indirect alloresponse further prolonged skin graft survival. This study supports an important role for B cells in indirect T cell priming and further emphasizes the advantage of combination therapies in prolonging transplant survival.

Evaluation of Radiofrequency AblationIrrigation Type: InVivo Comparison of Normal Versus Half-Normal SalineLesionCharacteristics.

This study investigated the impact of the type of catheter irrigant used during delivery of radiofrequency ablation. The use of half-normal saline (HNS) as an irrigant has been suggested as a method for increasing ablation lesion size but has not been rigorously studied in the beating heart or the use of a low-flow irrigation catheter. Sixteen swine underwent left ventricular mapping and ablation using either normal saline (NS) (group 1: n=9) or half-normal saline (HNS) (group 2: n=7). All lesions were delivered using identical parameters (40W with 10-second ramp, 30-second duration, 15ml/min flow, and 8- to14-g target contact force). An occurrence of steam pop, catheter char, or thrombus was assessed using intracardiac echocardiography and catheter inspection following each application. Lesion depth, width, and area were measured using electronic calibers. A total of 109 lesions were delivered in group 1 and 77 in group 2. There were significantly more steam pops in group 2 (32 of 77 [42%] vs. 24 of 109 [22%], respectively). The frequencies of catheter tip char were similar (group 1: 9 of 109 [8%] vs. group 2: 10 of 77 [13%]; p=0.29). Lesion depths, widths, and areas also were similar in both groups. The use of an HNS irrigant using a low-flow open irrigated ablation catheter platform results in more tissue heating due to higher radiofrequency current delivery directed to tissue, but this can lead to higher rate of steam pops. In this invivo porcine beating-heart model, the use of HNS does not appear to significantly increase lesion size innormal myocardium despite evidence of increased radiofrequency heating.

In vitro Intestinal Epithelial Wound-healing Assays Using Electric Cell-Substrate Impedance Sensing Instrument.

Here, we describe an in vitro epithelial wound-healing assay using Electric Cell-Substrate Impedance Sensing (ECIS) technology. The ECIS technology is a real time cell growth assay based on a small (250 μm diameter) active gold electrode which resistance is measured continuously. When intestinal epithelial cells reach confluency on the gold electrode, resistances reach a plateau. For the wound-healing assays, confluent intestinal epithelial monolayers are subjected to a current of 40 kHz frequency, 1,400 μA amplitude, and 30-second duration. This kills the cells around the small active gold electrode, causing detachment and generating a wound that is healed by surrounding cells that have not been submitted to the current pulse. Wound healing is then assessed by continuous resistance measurements for approximately 30 h after wound. Both cell wounding and measurements of the subsequent healing process are carried out under computer control that takes online measurements each 30 s and stores the data. ECIS technology can be used to study the underlying causes for impaired mucosal healing and to test the efficacy of drugs in mucosal healing.

Mobilization of Cardiovascular Function at Onset of Dosed Aerobic and All-Out Anaerobic Workouts

The objective of this study was to compare the peculiarities in the mobilization of cardiovascular function at the onsetof an exercise test in dependence on age and the type of adaptation to physical loads. The study’s participants were boysof 11, 12, 13 and 14 years old and adults, i. e. 17 voluntary students who were not engaged in sports training and well-trained athletes (all participants were members of various national teams), i. e. 23 athletes in the endurance group, 19 —in the sprint group and 21 — in the combative sports group (box, judo and wrestling). The subjects underwent:1) Roufier’s test (30 squats per 45 seconds); 2) a 30-second duration maximal vertical jump test. A computerizedelectrocardiogram (ECG) system “Kaunas-Load” was employed for the 12-lead ECG recording and analysis during theperformance of workloads. A computerized program allowed to measure the ratio of JT and RR intervals (JT / RR) andthe velocity of adaptation of cardiovascular system to exercise, i.e. the index of velocity of adaptation (V Ad ), by calculationthe difference between the relative changes of JT and RR intervals as a difference: V Ad . = (Jt i / JT 0 ) 100% – (Rr i / RR 0 ) 100%. The results obtained during the study allowed to conclude that faster adaptation at the onset of the exerciseis rather characteristic for younger persons but the type of the exercise performed during the long term training processplays a significant role in the developing and improving the velocity of adaptation of cardiovascular system. A fasteradaptation at the onset of the exercise is a more characteristic feature for the trained athletes in sprint events andcombative sports than the representatives of the endurance group or non-athletes. One of the effects of long termadaptation to exercise is a smaller mobilization of cardiovascular system at the onset of the dosed aerobic and all-outanaerobic exercise and the endurance exercise has the most influence on it.Keywords: cardiovascular system, adaptation, exercise test.

Improving the strength of sutureless laser-assisted vessel repair using preloaded longitudinal compression on tissue edge.

Little is known about the approximation of coapted edges in sutureless laser-assisted vessel welding. Tissue shrinkage by laser irradiation may cause coapted edges to separate, reducing strength of welding. This may be avoided by preloaded longitudinal compression on the tissue edges to be welded. This study compared welding strength with and without preloaded compression in ex vivo animal experiments. This study evaluated 24 samples of harvested porcine carotid arteries, each having a length of 3 cm and an inner diameter of 1.0-2.0 mm. A half circumferential incision was made at the center of each sample. A steel shaft 2.0 mm in diameter was inserted into each sample to approximate the incised edges. The samples were longitudinally compressed to 6 mm. Incision sites were repaired by irradiation with a 970-nm diode laser. No glue or die was used. The repair strength was evaluated by measuring the bursting point (BP) of all samples. In a pilot study, the welding conditions, including power, duration, and interval of the laser spots, were tested by trial and error in 18 samples, including six treated under optimum conditions. As a control group, six samples were welded under optimum conditions, but without compression. Optimum conditions, consisting of 2.4 W power, 30-second duration, and 1-mm intervals of laser spots, yielded the highest BP (623 ± 236 mmHg), which was significantly higher than in the control group without compression (204 ± 208 mmHg, P = 0.009). Defining BP > 400 mmHg as successful repair, the success rates in the compression and control groups were 83% and 17%, respectively. Preloaded longitudinal compression on the coapted edges may be important for sutureless laser-assisted vessel repair and anastomosis and may affect the strength of welding. Lasers Surg. Med. 49:533-538, 2017. © 2017 Wiley Periodicals, Inc.

Severe COPD Alters Muscle Fiber Conduction Velocity During Knee Extensors Fatiguing Contraction

The aim of this study was to assess the changes in muscle fiber conduction velocity (CV), as a sign of fatigue during knee extensor contraction in patients with chronic obstructive pulmonary disease (COPD) as compared with healthy controls. Eleven male patients (5 with severe and 6 with moderate COPD; age 67 ± 5 years) and 11 age-matched healthy male controls (age 65 ± 4 years) volunteered for the study. CV was obtained by multichannel surface electromyography (EMG) from the vastus lateralis (VL) and medialis (VM) of the quadriceps muscle during isometric, 30-second duration knee extension at 70% of maximal voluntary contraction. The decline in CV in both the VL and VM was steeper in the severe COPD patients than in healthy controls (for VL: severe COPD vs. controls −0.45 ± 0.07%/s; p < 0.001, and for VM: severe COPD vs. controls −0.54 ± 0.09%/s, p < 0.001). No difference in CV decline was found between the moderate COPD patients and the healthy controls. These findings suggest that severe COPD may impair muscle functions, leading to greater muscular fatigue, as expressed by CV changes. The results may be due to a greater involvement of anaerobic metabolism and a shift towards fatigable type II fibers in the muscle composition of the severe COPD patients.

Effect of a Core Conditioning Intervention on Tests of Trunk Muscular Endurance in School-Aged Children

Trunk and core muscular development has been advocated to increase athletic performance and for maintenance of musculoskeletal health, especially related to the prevention of low back pain (LBP). The purpose of this study was to examine the effects of a simple core conditioning routine on tests of trunk and core muscular endurance in school-aged children. Participants included 164 students (86 girls, 78 boys; mean age, 11.5 ± 2.5 years) recruited from a grade school in a metropolitan area located in the southwestern United States. Students performed an equipment-free, moderate-to-high intensity, dynamic core conditioning warm-up routine once a week for a period of 6 weeks during the start of their physical education classes. The intervention consisted of 10 different dynamic core conditioning exercises performed at a 30-second duration per exercise totaling 5 minutes per session. Pre- and post-assessments of muscular endurance consisted of 5 different trunk and core muscular endurance tests: Parallel Roman Chair Dynamic Back Extension, Prone Plank, Lateral Plank, Dynamic Curl-Up, and Static Curl-up. A generalized estimation equation was used to analyze differences in pre- and post-intervention muscular fitness assessments controlling for gender and grade level. Analysis of the data revealed significant increases in muscular fitness test performance for each of the 5 measured outcomes (p < 0.001). Because risk factors of LBP are thought to commence during childhood, results of this study suggest that it may be desirable for children and adolescents to perform moderate-to-high intensity dynamic core exercises during physical education warm-up to improve trunk and core muscular endurance.

Plantar-flexor static stretch training effect on eccentric and concentric peak torque – a comparative study of trained versus untrained subjects

The aim of this study was to examine the long-term effects of static stretching of the plantar-flexor muscles on eccentric and concentric torque and ankle dorsiflexion range of motion in healthy subjects. Seventy five healthy male volunteers, with no previous history of trauma to the calf that required surgery, absence of knee flexion contracture and no history of neurologic dysfunction or disease, systemic disease affecting the lower extremities were selected for this study. The participants were divided into three equal groups. The control group did not stretch the plantar-flexor muscles. Two Experimental groups (trained and untrained) were instructed to perform static stretching exercise of 30 second duration and 5 repetitions twice daily. The stretching sessions were carried out 5 days a week for 6 weeks. The dorsiflexion range of motion was measured in all subjects. Also measured was the eccentric and concentric torque of plantar-flexors at angular velocities of 30 and 120°/s pre and post stretching. Analysis of variance showed a significant increase in plantar-flexor eccentric and concentric torque (p < 0.05) of trained and untrained groups, and an increase in dorsiflexion range of motion (p < 0.05) at both angular velocities for the untrained group only. The static stretching program of plantar-flexors was effective in increasing the concentric and eccentric plantarflexion torque at angular velocities of 30 and 120°/s. Increases in plantar-flexors flexibility were observed in untrained subjects.

Physiological Responses during Interval Training with Different Intensities and Duration of Exercise

The purpose of this study was to compare 4 interval training (IT) sessions with different intensities and durations of exercise to determine the effect on mean VO₂, total VO₂, and duration of exertion ≥95% maximum power output (MPO), and the effects on biomarkers of fatigue such as blood-lactate concentration (BLC) and rating of perceived exertion. The subjects were 12 recreationally competitive male (n = 7, mean ± SD age = 26.2 ± 3.9 years) and female (n = 5, mean ± SD age = 27.6 ± 4.3 years) triathletes. These subjects performed 4 IT sessions on a cycle ergometer varying in intensity (90 and 100% MPO) and duration of exercise (30 seconds and 3 minutes). This study revealed that IT using 30-second duration intervals (30-30 seconds) allows the athlete to perform a longer session, with a higher total and mean VO₂ HR and lower BLC than 3-minute durations. Similarly, submaximal exertion at 90% of MPO also allows performing longer sessions with a higher total VO₂ than 100% intensity. Thus, the results of the present study suggested that to increase the total time at high intensity of exercise and total VO₂ of a single exercise session performed by the athlete, IT protocols of short durations (i.e., 30 seconds) and submaximal intensities (i.e., 90% MPO) should be selected. Furthermore, performing short-duration intervals may allow the athlete to complete a longer IT session with greater metabolic demands (VO₂) and lower BLC than longer (i.e., 3 minutes) intervals.

Alongamento muscular segmentar melhora função e alinhamento do joelho de indivíduos com síndrome femoropatelar: estudo preliminar

INTRODUÇÃO: A síndrome femoropatelar (SFP) é uma desordem dolorosa comum do joelho e para seu tratamento normalmente são utilizados exercícios de fortalecimento do músculo quadríceps femoral, sendo que poucos trabalhos encontrados na literatura investigaram os efeitos diretos do alongamento muscular. OBJETIVO: O objetivo deste estudo foi avaliar os efeitos do alongamento muscular segmentar no tratamento de pacientes com SFP. MÉTODOS: Participaram do estudo 12 voluntários com SFP, dominância de membro inferior direito e idade média de 20 anos. As variáveis funcionais avaliadas antes e depois do tratamento foram: ângulo Q, intensidade da dor, capacidade funcional pela escala de contagem de Lysholm, sensação de posição articular (SPA) a 40 e 50 graus de flexão do joelho, trabalho total e momento de força concêntrico dos músculos quadríceps femoral e isquiotibiais a 60 e 180º/s. Após a avaliação inicial, foi realizado o tratamento que consistiu em alongamento muscular segmentar bilateral dos músculos isquiotibiais, tríceps sural e quadríceps femoral, com duração de 30 segundos e 10 repetições para cada músculo. As variáveis avaliadas antes e após o tratamento foram analisadas pelo teste t para amostras dependentes (α &lt; 0,05). RESULTADOS: Todas as variαveis apresentaram diferença significante após o tratamento (p &lt; 0,05), exceto o momento de força e trabalho total dos músculos extensores a 60°/s, trabalho total dos extensores e flexores a 180º/s e a SPA a 50 e 40 graus de flexão do joelho. CONCLUSÃO: Os resultados desta pesquisa permitem inferir que o tratamento com alongamento muscular segmentar possibilita melhoras de vários sinais e sintomas apresentados pelos pacientes com SFP, como alinhamento, dor e função do joelho.

Creatine supplementation spares muscle glycogen during high intensity intermittent exercise in rats

BackgroundThe effects of creatine (CR) supplementation on glycogen content are still debatable. Thus, due to the current lack of clarity, we investigated the effects of CR supplementation on muscle glycogen content after high intensity intermittent exercise in rats.MethodsFirst, the animals were submitted to a high intensity intermittent maximal swimming exercise protocol to ensure that CR-supplementation was able to delay fatigue (experiment 1). Then, the CR-mediated glycogen sparing effect was examined using a high intensity intermittent sub-maximal exercise test (fixed number of bouts; six bouts of 30-second duration interspersed by two-minute rest interval) (experiment 2). For both experiments, male Wistar rats were given either CR supplementation or placebo (Pl) for 5 days.ResultsAs expected, CR-supplemented animals were able to exercise for a significant higher number of bouts than Pl. Experiment 2 revealed a higher gastrocnemius glycogen content for the CR vs. the Pl group (33.59%). Additionally, CR animals presented lower blood lactate concentrations throughout the intermittent exercise bouts compared to Pl. No difference was found between groups in soleus glycogen content.ConclusionThe major finding of this study is that CR supplementation was able to spare muscle glycogen during a high intensity intermittent exercise in rats.

The Brain Processing of Scratching

Neuroimaging studies have examined the neural networks activated by pruritus but not its behavioral response, scratching. In this study, we examine the central sensory effects of scratching using blood oxygen level-dependent functional magnetic resonance imaging (fMRI) in 13 healthy human subjects. Subjects underwent functional imaging during scratching of the right lower leg. Scratching stimulus was started 60 seconds after initiation of fMRI acquisition and was cycled between 30-second duration applications of scratching and 30-second duration applications of no stimuli. Our results show that repetitive scratching induces robust bilateral activation of the secondary somatosensory cortex, insular cortex, prefrontal cortex, inferior parietal lobe, and cerebellum. In addition, we show that the same stimulus results in robust deactivation of the anterior and posterior cingulate cortices. This study demonstrates brain areas (motor, sensory, and non-sensory) activated and deactivated by repetitive scratching. Future studies that investigate the central effects of scratching in chronic itch conditions will be of high clinical relevance.

A Comparison of Two Stretching Protocols on Hip Range of Motion

It is theorized that the total stretch time in a day is more important than the actual single stretch duration time. The purpose of this study was to compare 2 stretching protocols, keeping total stretching time equivalent. The 2 protocols were a 10-second duration stretch and a 30-second duration stretch. Although the stretch durations differed, the total stretching time over the course of a day was held constant at 2 minutes for both protocols. Participants were randomly assigned a protocol to each of their legs: subjects stretched 1 leg with the 10-second protocol and the opposite leg with the 30-second protocol. The 10-second stretch was repeated 6 times for a total of 1 minute; the 30-second protocol was repeated 2 times for a total of 1 minute. Stretching was performed twice daily (a total of 2 minutes each day) for 6 weeks. All stretching was performed to the hamstring muscles. Hip flexion measurements were recorded at pretest, 3-weeks, and 6-weeks. Subjects demonstrated significant gains in range of motion for hip flexion over the course of 6 weeks, p = 0.000. No differences existed between the 2 protocols. Range of motion gains were equal between the 2 stretching protocols. The common denominator was total stretch time for a day. Regardless of the duration of a single stretch, the key to improvement was the total daily stretch time. These findings are important as they allow clinicians and individuals to customize stretching protocols to meet individual needs.

Effects of injection duration on site-pain intensity and bruising associated with subcutaneous heparin.

The research evaluated two subcutaneous heparin injection techniques to determine the effects of different injection duration (10- and 30-seconds) on site-pain intensity and bruising. The research was instigated because nurses and patients in the hospital under investigation reported a high incidence of site-pain and bruising associated with subcutaneous heparin therapy. This research was conducted over a period of 7 months between September 1998 and April 1999. The Ethic Committees of the University and the hospital approved the research. The research used a within-subjects, quasiexperiment, which would yield more convincing causal inferences, owing to the assumption that pain perception and physiological factors affecting coagulation varied less in the same subject than in two comparable subjects. The research involved 34 stroke patients receiving low-molecular weight heparin. For each subject, one of the two injection techniques was used as the first injection and 12 hours later the other injection technique as the second injection. Subjects rated the level of perceived site-pain intensity using the vertical visual analogue scale (VAS). Injection-site bruising were measured at 48 and 60 hours after each injection. Digital planimetry was used to measure the surface-area of bruise tracings. The final data set for analysis consisted of 68 VAS pain scores and 136 bruise sizes. As normality of the data could not met after transformations, Wilcoxon Signed-Rank tests were used to determine the effects caused by injection duration on site-pain and bruise size. The level of significance was determined at P < 0.05. Results indicated that the 30-second duration injection technique resulted in significantly less intense site-pain and fewer and smaller bruises. It was concluded that administering a subcutaneous heparin injection over longer duration reduces injection site-pain and bruising. However, the convenience, relatively small sample may limit the generalisability of the research findings.

Ritodrine Hydrochloride and Preterm Labor

A primigravida is admitted to the labor and delivery unit complaining of intermittent backache and abdominal cramping. She has had an uncomplicated pregnancy and there is no evidence of ruptured amniotic membranes. Fetal gestational age of 32 weeks correlates with fundal height and date of last menstrual period. The fetal heart rate is 130 to 140. Mild contractions of 30-second duration can be felt every 4 to 5 minutes. A vaginal exam reveals 3 cm dilation, 80 percent effacement, and 0 station. Urinalysis from a sterile catheterized specimen is negative for bacteria and white blood cells. The obstetrician orders an immediate intravenous infusion of ritodrine hydrochloride (Yutopar)-a uterine relaxant. The obstetrical