Toxicologic evaluations of DHA-rich algal oil in rats: developmental toxicity study and 3-month dietary toxicity study with an in utero exposure phase.

DHA-rich algal oil ONC-T18, tested for subchronic, reproductive, and developmental toxicity in the rat, did not produce any significant toxicologic manifestations. Based on the absence of maternal or developmental toxicity at any dosage level, a dosage level of 2000 mg/kg/day was considered to be the no observed adverse-effect level (NOAEL) for maternal toxicity and embryo/fetal development when DHA-rich algal oil was administered orally by gavage to pregnant Crl:CD(SD) rats during gestation days 6-19. In a dietary combined one-generation/90-day reproductive toxicity study in rats, the NOAEL for F0 male and female and F1 male systemic toxicity was considered to be 50,000 ppm (highest concentration administered) and 25,000 ppm for F1 female systemic toxicity (higher mean body weight, body weight gain, and food consumption). F0 reproductive performance values, estrous cycle length, gestation length, or the process of parturition, and the numbers of former implantation sites and unaccounted-for sites were unaffected by algal oil exposure. Postnatal survival and developmental parameters in the F1 generation were unaffected by algal oil exposure at all dietary concentrations. There were no neurotoxic effects noted at any algal oil exposure level. The results support the safety of DHA-rich algal oil for its proposed use in food.

Toxicologic evaluation of DHA-rich algal oil: Genotoxicity, acute and subchronic toxicity in rats.

DHA-rich algal oil ONC-T18, tested in a battery of in vitro and in vivo genotoxicity tests, did not show mutagenic or genotoxic potential. The acute oral LD50 in rats has been estimated to be greater than 5000 mg/kg of body weight. In a 90-day subchronic dietary study, administration of DHA-rich algal oil at concentrations of 0, 10,000, 25,000, and 50,000 ppm in the diet for 13 weeks did not produce any significant toxicologic manifestations. The algal oil test article was well tolerated as evidenced by the absence of major treatment-related changes in the general condition and appearance of the rats, neurobehavioral endpoints, growth, feed and water intake, ophthalmoscopic examinations, routine hematology and clinical chemistry parameters, urinalysis, or necropsy findings. The no observed adverse effect level (NOAEL) was the highest level fed of 50,000 ppm which is equivalent to 3,305 and 3,679 mg/kg bw/day, for male and female rats, respectively. The studies were conducted as part of an investigation to examine the safety of DHA-rich algal oil. The results confirm that it possesses a toxicity profile similar to other currently marketed algal oils and support the safety of DHA-rich algal oil for its proposed use in food.

Bronchoalveolar lavage in children with cystic fibrosis: how many lobes should be sampled?

BACKGROUND: The European Respiratory Society guidance on bronchoalveolar lavage (BAL) in children was published in 2000. It recommended taking one BAL specimen from the most affected lobe or from the right middle lobe in diffuse disease. In 2007, the European Respiratory Society modified the recommendations for children with cystic fibrosis (CF), suggesting two BAL specimens (right middle lobe and the lingula or the most affected lobe). OBJECTIVE: To determine if BAL samples from one or two lobes give the full picture of lower airway infection in children with CF. DESIGN, SETTING AND PATIENTS: A retrospective review of all paediatric patients with CF who underwent flexible bronchoscopy between May 2007 and May 2009 was undertaken. MAIN OUTCOME MEASURES: As BAL specimens from all six lobes were collected, the BAL results were reviewed to identify if positive cultures would have been missed if only one lobe (right middle or most affected) or two lobes (right middle plus the lingula or most affected) had been sampled. RESULTS: The results of 39 bronchoscopic procedures in 31 children were reviewed. The BAL samples were taken from 6 lobes in all 39 procedures. Had only one lobe been used, 26 positive cultures (14 organisms) would have been missed in 11 patients. Had two lobes been used, 12 positive cultures (8 organisms) would have been missed in 7 patients. CONCLUSION: A single-lobe BAL is insufficient in assessing patients with CF for lower airway infection. Even when BAL specimens are taken from two lobes, a number of infections may be missed.

Approaches to improving breast screening uptake: evidence and experience from Tower Hamlets.

This paper reports on an innovative whole-systems approach to improving uptake of breast screening in Tower Hamlets, a deprived borough in the East End of London with a large minority ethnic population. The approach, developed by the public health team at NHS Tower Hamlets, draws on analysis of needs and existing literature about effective interventions to promote breast screening. Social marketing research led to a campaign targeted at Bangladeshi women, together with a range of initiatives to promote breast screening through primary care services and community outreach through local well-known organisations. The breast screening service itself was upgraded and a new service specification is being introduced from April 2009.

Electromyographic analysis of a human powered stepper cycle during seated and standing riding.

This study examined the muscular activation patterns produced while riding the Step 'n Go, a tricycle powered by a reciprocating vertical motion and typically used by individuals with cognitive, orthopedic, and neuromuscular conditions. Seven normal, adult subjects were tested at three power levels (75, 100, and 125 W) during seated and standing riding. Eight lower extremity muscles were examined with surface electromyography. Results showed that the major power producing muscles for this device were the gluteus maximus, vastis lateralis and medialis, rectus femoris, and tibialis anterior. At the highest power level, peak and mean muscular activation in these muscles were substantially lower (17-38%) while riding standing compared to seated, and seems to reflect the benefit of body weight for power production while standing. At the lowest power level, the peak and mean muscle activation differences between positions were less remarkable, and in some cases the standing values were greater than seated. This suggests that significant muscular effort was required to maintain standing posture and balance when riding at low power levels. Individuals able to perform vastis lateralis and medialis intensive activities, such as the concentric portion of a squat or using a stepping machine (Stair Master), should be able to comfortably ride the Step 'n Go at low power levels.

Primary care providers' views of precepting nurse practitioner students.

PURPOSE: To explore perceived barriers to and facilitators of precepting as viewed by experienced community-based preceptors. DATA SOURCES: Twenty-four nurse practitioner and physician preceptors participated in a 20-minute telephone interview, using a semi-structured format. The interviews were audio-taped and transcribed. Constant comparative analysis was used to organize the preceptors' responses into thematic categories. CONCLUSIONS: Overall, most preceptors were satisfied with the precepting experience; however, many preceptors cited increasing difficulty with teaching students in primary care sites due various organizational constraints such as the imperative to increase productivity. Good communication with school of nursing faculty was cited as the key factor to continued willingness to precept. IMPLICATIONS FOR PRACTICE: Understanding factors that are important for preceptors continuing in their clinical teaching role is important for schools of nursing, especially given the increasing time-limitations that many providers face due to social and economic changes in health-care delivery.

Ultrasound shear wave imaging for bone.

Recently, a computer-controlled scanning ultrasound (US) imaging system was developed in our laboratory. It includes a pair of broadband 48-MHz focusing copolymer transducers. The apertures of the transducers and their f-numbers were identically equal to 2 mm and 2.25, respectively. A specimen can be moved in a 10-microm increment in its plane and its normal direction can be rotated along the US propagation direction. It can be used to produce transmission-mode images of shear waves, as well as longitudinal waves for solid specimens. Shear waves in solids were generated by mode conversion. The results of the longitudinal and shear-wave US images for a piece of compact bovine bone obtained using this system are presented. Shear-wave images combined with longitudinal images can provide a more complete mechanical characterization of bone.

Three-dimensional kinematics and trunk muscle myoelectric activity in the elderly spine - a database compared to young people.

OBJECTIVE: To establish a database of lumbar spine kinematics and muscle activation profiles for a healthy elderly population. DESIGN: Spine motion parameters and muscle activation profiles of the elderly were identified and quantified in part by comparison with an existing database of younger people. BACKGROUND: Databases are often used as a benchmark to establish what is "normal", or for developing appropriate exercise programs or diagnostic methodologies. METHODS: Twelve people (average age 69 yr) performed full range of motion movements about the flexion, lateral bending and axial twist axes of the lumbar spine. Fourteen torso muscles (7 per side) were monitored with electromyographic electrodes and the signals normalized to maximum voluntary efforts. RESULTS: The elderly were slower moving, and had a reduced range of motion in full flexion and lateral bend but not in axial twist. Furthermore there was more coupled motion evident in the twisting efforts of the elderly. Abdominal muscles appeared to become more active, earlier in the lateral bending movement. CONCLUSIONS: Loss of motion is normal with age together with subtle changes in the way the spine moves and groups of muscles are recruited around the torso. RELEVANCE: Quantification of "normal" changes associated with aging will enable clinicians and scientists to distinguish normal changes from pathology.

Reliability of spectral EMG parameters of healthy back extensors during submaximum isometric fatiguing contractions and recovery.

Spectral EMG parameters are being used as an objective evaluation of low back rehabilitation programs. The reliability of these spectral parameters is important in determining the validity of this evaluation tool. Two groups of eight subjects, with no history of back pain, were measured: the first group every day for one week; the second group one day per week for four weeks. During each session, subjects performed a 30-second isometric fatiguing contraction of the back extensors at 60% MVC followed by a 60-second rest and a 10-second repeat contraction. The intraclass correlation coefficient (ICC) did not demonstrate high reliability (ICC < 0.6) for the rate of median power frequency (MedPF) change (Hz/s), the magnitude of the recovery (Hz) and differences between the dominant and the non-dominant sides within a subject. However, the initial MedPF (Hz) of the fatigue and repeat contractions demonstrated excellent reliability (ICC > 0.8) with five or more repeated measures. The practical implication of this work is that the experimental condition must have sufficiently large changes in MedPF (signal)--at least larger than the variability inherent in the MedPF (noise)--to constitute a valid measure.

Does methocarbamol affect fatigue markers in the low-back electromyogram?

Many low-back patients undergo electromyography (EMG)-based evaluations of muscle performance but present to the clinic after being prescribed muscle relaxants. The question that needed to be addressed was, do centrally acting muscle relaxants (methocarbamol; Robaxin) affect the EMG spectral indices of muscle fatigue that are often used to assess muscle performance. Participants performed an isometric spine extension protocol involving a 30 s fatigue exertion trial, then 1 min rest, and finally a 10 s long repeat exertion trial, at a 60% maximum voluntary contraction (MVC) level of exertion. Seven men were tested on two separate days (approximately 3-7 days apart), one day while medicated (six doses) with Robaxin and on another while not medicated. Specifically, the following parameters were studied in the bilateral multifidus (L5), lower erector spinae (L3) and upper erector spinae (T9): the slope of median power frequencies (MPFs) over the duration of the trial and the initial y-intercept of the MPF. The results generally suggest that methocarbamol (Robaxin) does not have any significant affect on the EMG median power frequency of the extensors during a fatiguing contraction followed by a repeat exertion, at least in normal people (one exception was observed--one side of multifidus at L5). However, given that this appears to be the first study of its kind, and that a relatively small number of subjects were used in this study, further investigation is needed to make a definitive conclusion about the effects of this drug on the several features of the electromyogram, over a broad spectrum of the clinical population performing a wider variety of tasks.

Classification of low back pain with the use of spectral electromyogram parameters.

STUDY DESIGN: An electromyogram procedure using spectral parameters to distinguish subjects with low back pain from those without. OBJECTIVES: To add to the growing database on this procedure, to assess the possible overfitting of data in the classification model, to determine whether a model based on a contraction level of 60% of maximum voluntary contraction can produce concordance rates similar to those in models based on 40% and 80% of maximum voluntary contraction, and to develop a classification model to distinguish subjects with low back pain from those without. SUMMARY OF BACKGROUND DATA: Other investigators have published a series of models in which spectral parameters measured during fatiguing contractions from the paraspinal muscles have been able to classify a subject into a low back pain or non-low back pain group with a more than 80% concordance rate. METHODS: Subjects with chronic low back pain (N = 21) and without (N = 18) performed a series of isometric, fatiguing back extensor contractions in which the median power frequency was measured bilaterally from T9, L3, and L5. A Student's t test was used to determine which parameters would be entered into the classification models. Discriminant analysis and logistic regression procedures were used to develop models to classify subjects and were compared for overfitting of data based on the number of input parameters. The logistic regression method used a holdout group (N = 6) for validation. RESULTS: The discriminant analysis selected all 10 input parameters and was believed to overfit the data. Logistic regression selected two parameters and had a concordance rate of 92.4%. Five of the six subjects in the holdout group were correctly classified. CONCLUSIONS: The use of spectral parameters to classify subjects with low back pain from those without appears to have merit. Compared with discriminant analysis, logistic regression provided an equally powerful method for classifying these two groups but did not overfit the data. Models based on 60% of maximum voluntary contraction demonstrated results comparable with those of previous research using 40% and 80% of maximum voluntary contraction.

Three-dimensional kinematics and trunk muscle myoelectric activity in the young lumbar spine: a database.

OBJECTIVE: To document the three-dimensional (3D) kinematics of the lumbar spine and the myoelectric activity of trunk muscles throughout the range of motion in selected tasks performed by healthy subjects. DESIGN: A survey of a single population. SETTING: A research laboratory in a university setting. PARTICIPANTS: Twenty-four men and women, university-age, with no history of chronic lower back pain volunteered for this study. INTERVENTIONS: The selected tasks consisted of lateral bend and axial twists to the right and left plus four different flexion-extension tasks that varied a hand-held weight (10kg and 0kg), and flexion-extension velocity (free-paced and 20 degrees/sec). MAIN OUTCOME MEASURE: 3D lumbar spine kinematics and normalized, linear enveloped electromyogram (EMG) of trunk muscles. RESULTS: The motion time histories were illustrated graphically. Consistent spinal kinematics and EMG activation patterns during each task across subjects were seen. Peak displacement values between tasks, using one-way analysis of variance, showed no significant difference. CONCLUSION: A database of healthy spine kinematics and normalized linear enveloped trunk muscle activation patterns were developed for future comparison of elderly and pathological subjects.

Methodological considerations for using inductive sensors (3SPACE ISOTRAK) to monitor 3-D orthopaedic joint motion.

OBJECTIVE: To assess and improve methodological constraints of the 3SPACE ISOTRAK. DESIGN: Several data sets were used to evaluate the following constraints: the performance is adversely affected by close proximity of metallic objects or electromagnetic fields; the3SPACE field contaminates electromyography recordings; and cross-talk from one axis to the other two occurs if the Euler rotation sequence is not matched to the orthopaedic description and function of the joint in question. BACKGROUND: The 3SPACE ISOTRAK is one of the few instruments suitable for measurement of relative three-dimensional joint rotation, however several methodological constraints exist. RESULTS AND CONCLUSIONS: Generally, accuracy can be maintained by restricting offending objects from the sensitive zone between the transmitter and sensor and using long leads to afford the subject distance from computers and other electrical instrumentation; while contamination of EMG amplitude in the time domain can be minimized by using quality instrumentation, and on occasion modifying electrode orientation. Contamination of the EMG frequency content appears unavoidable at low levels of muscle contraction; and cross-talk between axes is minimized by matching the first Euler rotation with the axis of the joint that is characterized by the greatest expected angular displacement. RELEVANCE: The 3SPACE ISOTRAK is one of the few instruments available that is suitable for measuring three axes of relative joint motion (local joint axes that rotate with the joint -- not global). This paper suggests several techniques to increase the accuracy and viability of this instrument.