Biofilms in drinking water systems: a possible reservoir for Helicobacter pylori

A laboratory model system was utilised to investigate the persistence of Helicobacter pylori in mixed-species heterotrophic biofilms. A single-stage continuous culture vessel was linked to a modified-Robbins device (mRD) incorporating removable stainless steel coupons. The system was innoculated with H. pylori (NCTC 11637) and the fate of the organism monitored by polymerase chain reaction (PCR) analysis. Helicobacter pylori was detected in biofilm material for a period of up to 192 h. Theoretical washout would have occurred at around 48 h thus detection of H. pylori for a prolonged period after theoretical washout suggested that the organism possessed the ability to persist in the mixed-species heterotrophic biofilm. Preliminary studies using heat-inactivated H. pylori showed that the organism was not detected in biofilm material at any time post-challenge suggesting that the persistence of H. pylori in such material was a phenomenon requiring the organism to be in a viable state. Further investigations to assess the biological basis for the association of H. pylori with drinking water biofilms and the risk that this may pose to public health are being undertaken.

High-throughput mapping of protein occupancy identifies functional elements without the restriction of a candidate factor approach

There are a variety of in vivo and in vitro methods to determine the genome-wide specificity of a particular trans-acting factor. However there is an inherent limitation to these candidate approaches. Most biological studies focus on the regulation of particular genes, which are bound by numerous unknown trans-acting factors. Therefore, most biological inquiries would be better addressed by a method that maps all trans-acting factors that bind particular regions rather than identifying all regions bound by a particular trans-acting factor. Here, we present a high-throughput binding assay that returns thousands of unbiased measurements of complex formation on nucleic acid. We applied this method to identify transcriptional complexes that form on DNA regions upstream of genes involved in pluripotency in embryonic stem cells (ES cells) before and after differentiation. The raw binding scores, motif analysis and expression data are used to computationally reconstruct remodeling events returning the identity of the transcription factor(s) most likely to comprise the complex. The most significant remodeling event during ES cell differentiation occurred upstream of the REST gene, a transcriptional repressor that blocks neurogenesis. We also demonstrate how this method can be used to discover RNA elements and discuss applications of screening polymorphisms for allelic differences in binding.

Next-generation SELEX identifies sequence and structural determinants of splicing factor binding in human pre-mRNA sequence

Many splicing factors interact with both mRNA and pre-mRNA. The identification of these interactions has been greatly improved by the development of in vivo cross-linking immunoprecipitation. However, the output carries a strong sampling bias in favor of RNPs that form on more abundant RNA species like mRNA. We have developed a novel in vitro approach for surveying binding on pre-mRNA, without cross-linking or sampling bias. Briefly, this approach entails specifically designed oligonucleotide pools that tile through a pre-mRNA sequence. The pool is then partitioned into bound and unbound fractions, which are quantified by a two-color microarray. We applied this approach to locating splicing factor binding sites in and around approximately 4000 exons. We also quantified the effect of secondary structure on binding. The method is validated by the finding that U1snRNP binds at the 5' splice site (5'ss) with a specificity that is nearly identical to the splice donor motif. In agreement with prior reports, we also show that U1snRNP appears to have some affinity for intronic G triplets that are proximal to the 5'ss. Both U1snRNP and the polypyrimidine tract binding protein (PTB) avoid exonic binding, and the PTB binding map shows increased enrichment at the polypyrimidine tract. For PTB, we confirm polypyrimidine specificity and are also able to identify structural determinants of PTB binding. We detect multiple binding motifs enriched in the PTB bound fraction of oligonucleotides. These motif combinations augment binding in vitro and are also enriched in the vicinity of exons that have been determined to be in vivo targets of PTB.

Detection of Helicobacter pylori DNA in drinking water biofilms: implications for transmission in early life

AIMS

To provide evidence of water quality as a risk factor for acquisition of Helicobacter pylori in early life, and to identify evidence for its presence within pots used to store drinking water.

METHODS AND RESULTS

A prospective cohort study of 65 infants was conducted in the rural village of Keneba, The Gambia. Age of H. pylori colonization was determined and water pot biofilms were tested for H. pylori by sequencing of amplified DNA. Use of supplemental water was a strong risk factor for H. pylori colonization in infants (OR 4.71, 95% CI 1.17-22.5). DNA with 95% homology to the 16S rRNA gene of H. pylori was isolated from biofilms of water pots.

CONCLUSIONS

Drinking water may be a reservoir for H. pylori in areas of the developing world where water quality is poor. Early introduction of water, particularly if stored in, or collected from contaminated sources, may be associated with an increased rate of H. pylori colonization.

Helicobacter sp. recovered from drinking water biofilm sampled from a water distribution system

Workers examining the transmission route(s) and reservoir(s) of infection for Helicobacter pylori have postulated several environmental reservoirs for the organism, including water. Such work has, to date, concentrated on the bulk liquid in drinking water systems rather than on biofilms. Previous investigations by the authors have suggested biofilms in water distribution systems are a possible reservoir of infection. This current study comprised of an analysis of a section of cast iron mains distribution pipe removed from an urban environment in the north-east of Scotland during routine maintenance work. Immediately upon removal of the pipe section, the interior lumen was swabbed to remove the biofilm layer. Subsequent analysis for the presence of Helicobacter DNA using a nested PCR approach produced a positive result. This data provides the first evidence for the existence of Helicobacter in biofilms found in water distribution systems anywhere in the world.

Factors predicting employment 1 year after traumatic spine fracture

STUDY DESIGN

This prospective cohort study evaluates the employment status of 489 persons after traumatic spine fracture.

OBJECTIVES

To determine the rate, type, and predictors of employment 1 year after traumatic spine fracture.

SUMMARY OF BACKGROUND DATA

The limited existing literature regarding employment after spine fracture reports variable return-to-work rates, tends to be retrospective, and generally evaluates a limited number of predictor factors at a time.

METHODS

Four hundred eighty-nine persons ranging in age from 15 to 64 years who had experienced a spine fracture were assessed by a single examiner at hospital discharge and 1 year postinjury. Employment status and type. discharge neural and functional status, pain level, demographics, injury level and severity, and early treatment details were evaluated.

RESULTS

At 1 year postinjury, 54% of subjects were working. A higher percentage of the employed were working part time and for fewer weeks per year than preinjury. A higher percentage were working at unskilled clerical, sales, or service jobs than preinjury. The significant positive (+) and negative (-) predictors of employment were (from strongest to weakest); worked in year previous to injury (+); employed at time of injury (+); Worker's compensation Board coverage (-); spinal fracture surgery (+); high-level spine fracture (-); pain (-); Functional Independence Measure score (+); and days of stay in intensive care unit and spinal unit (-).

CONCLUSIONS

For the first year after spinal fracture, unemployment is common. Those who do return to work are more likely to modify the amount and type of work they do and to have been employed preinjury.

Postfabrication exposure of gap-type bandpass filters in broadly chirped fiber gratings

High efficiency in-fiber bandpass filters with arbitrary passband/stop-band combinations have been produced successfully with an UV postfabrication exposure technique in broadly chirped fiber gratings. By further concatenating such a bandpass filter with two additional chirped gratings we achieved a finesse as high as 220 for a 36-nm stop band. This new approach exhibits great advantages in controlling precisely the profiles of bandpass filters in terms of stop-band width, transmission wavelength and linewidth, and spacing of passbands.

Position of the cervical vertebrae during helmet removal and cervical collar application in football and hockey

There is lack of consensus among prehospital personnel (athletic therapists, paramedics, sport physiotherapists) concerning specific aspects of initial care and assessment of injured athletes presenting signs and symptoms of a cervical spine injury (CSI). In instances of serious injury involving the head and/or spine, complicated by altered levels of consciousness, protective equipment such as helmets and shoulder pads may provide a hinderance to prompt, safe and efficient management. Specifically, there is disagreement concerning the need or advisability of removing protective head gear, as in the case of football and hockey athletes. Using the technique of fluoroscopy, the cervical spine displacement of 21 male football and hockey athletes was determined while wearing protective shoulder pads and protective head equipment at the following times (a) during helmet removal, (b) during cervical collar application, and (c) as the helmetless head was allowed to rest. Subsequent frame-by-frame video arthokinematic analysis, using computer-assisted digitization, showed significant alterations in the position of adjacent cervical vertebrae during helmet removal, cervical collar application, and head rest. Results suggest that stabilization and transportation of football and hockey athletes with suspected CSI in their respective protective equipment is recommended in order to reduce the risk of further trauma by unnecessary cervical spine motion.

Shoulder abduction strength measurement in football players: reliability and validity of two field tests

Musculoskeletal and neurologic injuries affecting shoulder strength are common in contact sports. Full-strength recovery is desired before resumption of competition. On-field assessment of shoulder strength is usually done by manual muscle testing, which lacks sensitivity and reliability. Our objective was to determine the reliability and validity of two field instruments capable of quantifying shoulder abduction strength. Twenty junior football players underwent bilateral isokinetic (60 degrees/s) and isometric shoulder abduction strength measurements using a Cybex 340 isokinetic dynamometer. Test-retest measurements of both shoulders of each player were made using strain gauge (SG) and handheld dynamometer (HHD) instruments. Players were tested during rested and competition conditions. Within and between session reliabilities were calculated using the intraclass coefficient, and validity was assessed using Pearson's correlation coefficient. Overall reliability for each device was calculated using Lisrel analysis. SG was found to be superior to HHD in overall reliability and validity. Within-session reliability in the rested and competition states was 0.75 and 0.78, respectively, for SG and 0.60 and 0.81, respectively, for HHD. Between-session reliability in the rested and competition states dropped to 0.51 and 0.63, respectively, for SG and 0.55 and 0.70, respectively, for HHD. Validity was 0.41 and 0.70 for SG when correlated with Cybex at 0 degree and 60 degrees/s respectively. Validity for HHD was 0.28 and 0.42 for Cybex speeds of 0 degree and 60 degrees/s, respectively. SG reliability and validity were similar when testing was done one shoulder at a time or both shoulders concurrently.(ABSTRACT TRUNCATED AT 250 WORDS)

Shoulder pain in wheelchair athletes. The role of muscle imbalance

Shoulder rotator cuff impingement syndrome is a common and disabling problem for the wheelchair athlete. In this study we investigated the role of shoulder strength imbalance as a factor for the development of this syndrome. Nineteen paraplegic male athletes underwent clinical and isokinetic examination of both shoulders with peak torque values measured in abduction, adduction, and internal and external rotation. Twenty athletic, able-bodied men without shoulder problems were tested as controls. Ten (26%) of the paraplegic athletes had rotator cuff impingement syndrome. The results of the isokinetic testing demonstrated that 1) the paraplegics' shoulders were stronger than the controls in all directions (P < 0.05); 2) the strength ratio of abduction: adduction was higher for paraplegic athletes (P < 0.05); 3) paraplegics' shoulders with rotator cuff impingement syndrome were weaker in adduction and external and internal rotation than the paraplegic athletes without impingement syndrome (P < 0.05); and 4) paraplegics' shoulders with rotator cuff impingement syndrome had higher abduction:adduction and abduction:internal rotation strength ratios than the shoulders of paraplegics without impingement syndrome (P < 0.05). We concluded that shoulder muscle imbalance, with comparative weakness of the humeral head depressors (rotators and adductors), may be a factor in the development and perpetuation of rotator cuff impingement syndrome in wheelchair athletes.

Incomplete neural deficits in thoracolumbar and lumbar spine fractures. Reliability of Frankel and Sunnybrook scales

Because neural status is used both as a treatment determiner and outcome measure, a universal, reliable scale is required. Experienced personnel, provided with concise definitions, demonstrated high inter-rater reliability of Frankel and Sunnybrook scales (Pearson correlation coefficients 0.71-0.91), with 94-100% intra-rater agreement. Both scales correspond to total sensory and motor function but are insensitive to walking and bladder function. Frankel's wide clinical use, reliability, and simplicity identify it to be the preferred measurement system until a better alternative is developed. Discussion of neural status must include description of bladder and walking function.

Anterior compartment pressures in cross-country skiers. A comparison of classic and skating skis

This paper compares the pressure changes in the anterior compartment of the leg when cross-country skiing using the skating method on either skating skis or classic skis. Intracompartmental pressures of the right leg were recorded from the tibialis anterior muscle of 10 subjects at rest and 15 seconds after 10 to 12 minutes of cross-country skiing on a designated course. All subjects completed two trials on different days. In one trial, subjects used skating skis and for the other trial, classic skis were used for the skating technique. Although the average pressure increase was higher for the classic ski trials than for the skating ski trials, the difference was not significant. This finding indicates that cross-country skiers who skate on a classic ski as opposed to a shorter skating ski do not experience a significantly greater increase in their anterior compartment pressure. Thus, it appears that the type of ski used is not the most significant factor contributing to chronic compartment syndrome.

Influence of electrical stimulation on the morphological and metabolic properties of paralyzed muscle

Selected morphological and metabolic properties of single fibers were studied in biopsy samples from the tibialis anterior of normal control and spinal cord-injured (SCI) subjects. In the SCI subjects, one muscle was electrically stimulated progressively over 24 wk, in 6-wk blocks for less than or equal to 8 h/day, while the contralateral muscle remained untreated. The percentage of fibers classified as type I [qualitative alkaline preincubation myofibrillar adenosinetriphosphatase (ATPase)] was significantly less in the unstimulated paralyzed muscles than in the muscles of normal control subjects. Electrical stimulation increased the proportion of type I fibers in the SCI subjects. For both type I and type II fibers, the cross-sectional area, activities of myofibrillar ATPase and succinate dehydrogenase, and the capillary-to-fiber ratio were also significantly less in the paralyzed muscles than in the normal control muscles. Electrical stimulation increased only the activity of succinate dehydrogenase in both fiber types of the SCI subjects. These data are discussed in relation to the electromechanical properties of the respective muscles described in an accompanying paper (J. Appl. Physiol. 72: 1393-1400, 1992). In general, the electrical stimulation protocol used in this study enhanced the oxidative capacity and endurance properties of the paralyzed muscles but had no effect on fiber size and strength.

Effect of high velocity resistance training on peak torque, cross sectional area and myofibrillar ATPase activity

The purpose of this investigation was to determine the effect of high velocity resistance (HVR) training on peak torque (PT), cross sectional area (CSA) and myofibrillar ATPase activity of the knee extensors. HVR training was performed in a circuit on hydraulic exercise equipment, 4 times a week for 5 weeks at an angular velocity of approximately 3.14 rad.s-1. Knee extension PT was determined on a Cybex II isokinetic dynamometer and CSA of the quadriceps femoris muscle was assessed using computer tomography (CT) scanning. Muscle biopsies were obtained from the lateral quadriceps muscle and were analyzed for myofibrillar ATPase activity. Knee extension peak torque was significantly increased at 1.57, 2.09, 3.14, 3.66 and 4.19 rad.s-1. Myofibrillar ATPase activity and CSA was also significantly increased after HVR training. These findings showed that short-term high velocity resistance training enhances the in vivo torque/velocity curve especially at fast angular velocities and these changes are partly attributed to an increase in muscle CSA and activity of myofibrillar ATPase.

The effects of a reduced exercise duration taper programme on performance and muscle enzymes of endurance cyclists

The influence of tapering on the metabolic and performance parameters in endurance cyclists was investigated. Cyclists (n = 25) trained 5 days.week-1, 60 min.day-1, at 75-85% maximal oxygen consumption (VO2max) for 8 weeks and were then randomly assigned to a taper group: 4D (4 days; n = 7), 8D (8 days; n = 6), CON (control, 4 days rest; n = 6), NOTAPER (non-taper, continued training; n = 6). Muscle biopsy specimens taken before and after training and tapering were analysed for carnitine palmityltransferase (CPT), citrate synthase, beta-hydroxyacyl CoA dehydrogenase (HOAD), cytochrome oxidase (CYTOX), lactate dehydrogenase, glycogen and protein. Significant increases in VO2max (6%), a 60-min endurance cycle test (34.5%), oxidative enzymes (77-178%), glycogen (35%) and protein (34%) occurred following training. After the taper, HOAD and CPT decreased 25% (P less than 0.05) and 26% respectively, in the CON. Post-taper CYTOX values were different (P less than 0.05) for 4D and 8D compared with CON. Muscle glycogen levels were increased (P less than 0.05) after tapering in the 4D, 8D and CON, but decreased in NOTAPER. Similarly, power output at ventilation threshold was significantly increased in the 4D (27.4 W) and 8D (27 W) groups, but decreased (22 W) in the NOTAPER. These findings suggest that tapering elicited a physiological adaptation by altering oxidative enzymes and muscle glycogen levels. Such an adaptation may influence endurance cycling during a laboratory performance test.

Effect of systemic inhibition of prostaglandin synthesis on muscle protein balance after trauma in the rat

Anaesthetized rats were subjected to a single impact trauma to the medial aspect of the right hindlimb (gastrocnemius muscle), and were compared with sham-treated controls. For 3 days after injury, muscles of the traumatized limb showed a marked catabolic response. Muscle protein repletion commenced after day 3, however, this process was not complete until 21 days after injury. Muscles of the uninjured limb of the traumatized rats also showed a distinct catabolic response, compared with rats that were never injured, although this response was less in magnitude than that of the injured limb. At 3 days after trauma, augmented synthesis of prostaglandin (PG)E2 by muscles of the injured and uninjured limb provided evidence of a local and systemic inflammatory response. Inhibition of PG synthesis by the systemic administration of naproxen (6-methoxy-alpha-methyl-2-napthaleneacetic acid) significantly reduced the catabolic loss of muscle protein seen locally and peripherally to the injury site.

Multiple noncontiguous spine fractures

The data from a prospective study of 508 spine injuries were reviewed to determine the incidence of multiple noncontiguous spine fractures. All patients were examined at admission and at 1 and 2 years postinjury. This series identified 77 (15.2%) multilevel fractures. Motor vehicle accidents were the primary cause of these fractures. The incidence of neurologic injury was not significantly different between multiple noncontiguous and single fractures. Failure to use seat belts and ejection from the vehicle were the main factors associated with multiple noncontiguous spine injuries. Seven major fracture patterns were identified, which accounted for 60% of these injuries. The prognosis for multilevel spine fractures was not significantly worse that that for single-level injuries.

Ultrastructural events following acute muscle trauma

The purpose of this study was to determine the ultrastructural events occurring in skeletal muscle following acute blunt trauma. Male rats weighing 250 g were subjected to a single impact trauma to the medial gastrocnemius muscle while under general anesthesia. Hemorrhage, inflammation, non-necrotic degeneration, and later regeneration were observed. In the short term following impact (6-24 h), the damaged segments showed gross tearing and degeneration. A large number of mononuclear cells were seen in the intercellular connective tissue and within the damaged muscle cells. By 24-48 h, there was an increase in the number of sarcolemmal nuclei, some of which were likely of satellite cell origin. By day 3, regenerating muscle cells displayed central nuclei and reorganizing sarcomeres. By day 6, further progression of regeneration was seen. Moreover, focal interstitial collagen formation suggested minimal to mild scar formation. On days 14, 21, and 30 after trauma, the muscle appeared to have healed and no abnormalities could be found at the site of injury. In parallel with the ultrastructural events noted, the injured muscles underwent a marked catabolic response and showed a reproducible fall (-27%, P less than 0.001) in total protein content within 48 h. Muscle protein accumulation commenced after day 3; however, complete repletion of the loss did not occur until day 21 post-injury.

The influence of high-velocity circuit resistance training on VO2max and cardiac output

In order to investigate the influence of high-velocity circuit resistance training on maximal aerobic power, maximal stroke volume and cardiac output, and blood lactate removal during recovery, 16 habitually active males were blocked on initial VO2max into either training or control groups. The training group completed two (weeks 1 and 2) or three (weeks 3-6) circuits of 10 variable-resistance hydraulic exercise stations at an exercise: relief ratio of 1:2 on alternate days over six weeks. Angular velocities of movement were maintained at approximately 3.1 rad.s-1. Following training, the VO2max was increased (p less than .01) from 4.32 to 4.68 1.min-1. Maximal stroke volume was increased (p less than .05) from 120 to 129 mL and heart rate response to an absolute submaximal exercise load was decreased (p less than .05) from 153 to 146 beats.min-1. As well, enhanced (p less than .01) removal of lactate from the blood was observed during recovery from exhausting exercise. No changes were observed for control subjects. These results indicate that positive alterations in aerobic and cardiovascular function may be achieved consequent to high-velocity circuit resistance training.

Spine fractures in winter sports

In a 7-year review of 1,447 spine fractures, 202 (14%) were due to sporting or recreational causes, of which 84 (42%) were associated with paralysis. This high incidence catastrophic injury is second only to motor vehicle accidents. Snowmobiling (10%), skiing (5%), tobogganing (5%) and ice hockey (3%) accounted for approximately one-quarter of these injuries. Snowmobile injuries rose steadily over this period, and the main contributing factors were alcohol, poor lighting, young age and inappropriate terrain. The skiing injuries occurred to novices and top class skiers alike, with one-third of those sustaining a fracture having associated paralysis. In view of the terrain and the speeds involved, the figure is unlikely to change. An alarming trend was the subtle increase in cervical fracture due to ice hockey, most of which were compression injuries with the neck in the neutral or slightly flexible position, and secondary to a collision with the boards. Being decked from behind contributed to the impact. The introduction of measures to reduce these injuries is mandatory, since cervical fractures secondary to ice hockey were associated with permanent paralysis in 67% of the cases. There are several points of initial management which require emphasis.

Isokinetic muscle strength parameters for shoulder movements

A study was carried out on shoulder muscle strength using an isokinetic dynamometer device, and normal parameters were established on 20 men and 20 women for a total of 80 shoulders. This population consisted of fit, athletic individuals with a mean age of 26·65 years and 25·35 years for the women and men; respectively. Peak torque, angle of peak torque, and arc of maximum strength (= peak±2 N m) were measured. Emphasis was placed on the arc of maximum strength in that it may reflect a more functional measurement than the single angle value for peak torque. For all movements women were approximately 50% as strong as men. There were no significant differences between the means for dominant versus non-dominant arms. The strongest muscle group was the adductors, with a mean peak torque of 28·8 N m for women and 48·-0 N m for men. With 48 N m internal and external rotation, women had a significantly greater range of motion than men but the peak torques remained around the neutral position.

Sonation of lumbar nerve roots as a diagnostic procedure in patients with sciatica

It has been suggested that sonation of the lumbar nerve roots in patients with sciatica will precipitate their symptoms and therefore may be a useful diagnostic tool in the evaluation of disc protrusions. Thirty healthy subjects (Group 1), mean age 36 (+/- 6) years, were evaluated to establish a baseline response. None had a positive test. A second group of 35 individuals, mean age 38 (+/- 12) years, all had histories of sciatica and sufficient signs to warrant consideration of a myelogram. Subsequently, all had positive myelograms and positive disc protrusions documented at surgery. Only three of the second group had positive responses to the ultrasound test. The ultrasound was 870 kHz continuous at 2watts/cm2 for two minutes, administered at the lumbar paravertebral muscle mass. The ultrasound test had a high specificity and very low sensitivity (.09), indicating that sonation of the lumbar nerve roots in people with sciatica is not a useful preliminary screening test of low lumbar disc disease.

Prevention of hip and knee injuries in ballet dancers

Hip problems form about 10% (7.0 to 14.2%) of most published series of ballet injuries. The abnormally large range of external rotation needed for a perfect turnout is primarily due to soft tissue adaptation, more readily achieved in the young dancer. Insufficient range of motion at the hip throws considerable stress on the other lower limb segments. The snapping hip syndrome is common (43.8% of hip problems), with about one-third associated with pain. A tight iliotibial band may contribute to this, and balanced flexibility requires special attention to abductor stretching. The external clicking hip must be distinguished from the internal clicking hip, which is associated with the joint and psoas tendon. Stress fractures of the hip are easily overlooked and, if undetected, they may progress to a complete fracture. Knee problems account for 14.0 to 20% of complaints, and over 50% of these are peri- or retropatellar problems. This includes synovial plica, medial chondromalacia, lateral patella facet syndrome, subluxing patella and the fat pad syndrome. Specific diagnosis leads to specific treatment and the best chance of cure. Mild hyperextension of the knee may be aesthetically desirable, but excessive range leads to symptoms in the posterior capsule and poor control. Young dancers with a tendency to very lax joint structures should be identified early and protected from overstretching. In the author's series, meniscal lesions did not appear to be as big a problem as reported elsewhere in the literature. Ballerinas appear to have less leg strength than other groups of athletes, having only 77% of the weight-predicted norms. The introduction of strength training for male and female dancers may reduce injuries and improve balance, but it requires an intensive educational programme to dispense with the many myths. There are several references to the development of early arthritis but, while relatively common in the foot, symptomatic arthrosis in ballet dancers' hips and knees is not more prevalent than in the general population. The young age at which serious dance training begins, the long and rigorous hours of practice, the thin ballet slipper, dancing en pointe and unusual dietary regimens may all contribute to injury patterns in varying degrees.

The nonoperative treatment of burst fractures of the thoracolumbar junction

Treatment of thoracolumbar spine burst fracture with a neurologically intact patient is controversial, with advocates of operative and nonoperative approaches. Of 404 patients in a prospective spinal trauma study, 21 had burst fractures, were neurologically intact, and had greater than 1-year followup. This group was analyzed to evaluate treatment with early mobilization using a thoracolumbar total contact orthosis. The average time in a brace was 6 months. Two patients had pulmonary embolus treated successfully with anticoagulants. No patient required subsequent surgery for increasing kyphosis or neurologic deficit. Change in K angle at followup was 4.6 degrees (+/- 5.7) and change in anterior vertebral height was 6.1 degrees (+/- 10). All patients had a satisfactory pain score and most individuals returned to full employment. It is concluded that it is not necessary to routinely treat patients operatively with burst fractures if they fulfill the following criteria: 1) neurologically intact; 2) kyphosis angle less than 35 degrees; 3) other injuries do not preclude the use of a total contact orthosis; and 4) the patient is capable of understanding and cooperating with the treatment regime. These criteria are irrespective of the CT findings of posterior vertebral retropulsion and spinal canal narrowing.

Off-road recreational motor vehicle accidents: hospitalization and deaths

There is increasing concern over the unregulated use of recreational off-road motor vehicles. A review of 207 patients admitted to a tertiary care hospital over a 5-year period, as well as deaths due to use of recreational vehicles, elicited the following information. Recreational accidents predominantly involved men in their mid-twenties. Children younger than 16 years were more frequently involved in all-terrain vehicle (ATV) or dirt-bike accidents and constituted more than one-third of the total. There was a ninefold increase in ATV accidents over the study period, so that by 1985 ATVs were the primary cause of off-road injuries (52%). The musculoskeletal system was most frequently injured (66%) followed by the head and face (25%). There was permanent disability in 10.6%, and 33% of the recreational deaths were in children younger than 16 years. The inherent instability of ATVs was confirmed by the finding that in 60% of accidents the vehicle had rolled or flipped. Stricter licensing requirements should be implemented, and public education is required to draw attention to the danger of these vehicles, particularly to children. There is a need for proper safety equipment and driver training. The issue of vehicle design must also be addressed by the industries concerned.

Spine Trauma Associated With Off-Road Vehicles

In brief: A seven-year review of 1,447 cases of spine trauma showed a 10% increase in sports-related spine trauma from 1980 to 1986; 53 cases were associated with use of off-road vehicles (ATVs, snowmobiles, and motorized dirt bikes). Of these 53 injuries, the major contributing factors were alcohol or drug use, inadequate lighting, poor judgment, and young age. The authors suggest the development of safe riding areas, legislation governing safe operation of these vehicles, and a major public education campaign specifically geared toward parents, warning them of the dangers of allowing children to operate these machines.

A biomechanical evaluation of sorbothane

Sorbothane (I.E.M. Orthopaedics, Aurora, Ohio), a viscoelastic polymer, has been developed for orthopedic application, but there has been little substantiation of the claim that it is capable of absorbing 95% of the impact energy in foot strike. Sorbothane has been used extensively in orthotic insoles in order to minimize the symptoms of joint degeneration, prosthesis loosening, and various soft tissue disorders resulting from the impact generated at foot strike during walking and running. The viscoelastic properties of Sorbothane were investigated by Durometer tests at various temperatures as well as compression tests of thin discs of material with different degrees of lateral constraints and varying rates of loading. Sorbothane has the characteristics of a viscoelastic solid with a relaxation time of two seconds. The effects of lateral constraint were significant, indicating that the properties of this material will change when bonded to other substances in the production of insoles. The final transmitted stress over the duration of foot strike would not be reduced by more than 10%, which may have some therapeutic implication, but not of the magnitude suggested by other authors.

Etiology and clinical course of missed spine fractures

A prospective study was designed to document course and outcome. Two hundred fifty-three patients with 274 spinal injuries were reviewed at the time of injury and discharge from hospital, as well as at 1, 2, and 5 years postinjury. Thirty-eight of these patients were identified who had been misdiagnosed at the initial assessment. Fracture location, cause of injury, neurologic deficit, and delay in diagnosis were all documented: 22.9% of cervical injuries, and 4.9% of the thoracolumbar injuries had a delayed diagnosis ranging from less than 1 day to 36 days. The causes of delayed diagnosis were: 1) failure to take X-rays, 2) fractures missed on X-ray, and 3) failure of patients to seek medical attention. Associated factors such as intoxication of the patient, multiple injuries, level of consciousness, or two levels of spinal injury contributed to the delayed diagnosis of these injuries. Certain "at-risk" populations for missed spinal injuries have been identified. In spite of delays in diagnosis, progression of an established neurologic deficit did not appear to occur in our study. However, the development of secondary deficits was significant in the delayed diagnosis group.

Lower extremity flexibility patterns in classical ballet dancers and their correlation to lateral hip and knee injuries

Knee and hip problems account for up to 40% of injuries in classical ballet. Despite apparent flexibility, many dancers appeared to have tight iliotibial bands that contributed to lower limb problems. Thirty senior female ballet dancers were contrasted with thirty age-matched active volunteers for hip and knee range of motion, and the information derived was correlated with their orthopaedic medical histories. Dancers spent a reasonable period of time warming up, but it was usually with an unbalanced routine that emphasized hip abduction and external rotation to the exclusion of adduction work. This was reflected in the significantly lower range of passive hip adduction and internal rotation compared to the controls. Furthermore, the older and more experienced the dancer, the more this trend was exaggerated. This unbalanced flexibility may play a role in the production of lateral knee pain (30% of the dancers) and anterior hip pain (33% of the dancers). It is suggested that more attention should be given to a balanced stretching regimen as part of the dancers' warmup in an effort to reduce the frequency of some of the chronic hip and knee complaints.

A comparison of muscle fiber characteristics at different levels of the vertebral column in the rhesus monkey

The vertebral muscle fiber characteristics of adult female rhesus monkeys have been examined. Muscle samples were obtained from precisely defined superficial and deep sites on both sides of the vertebral column. In particular, samples were collected from three different levels of the column and the muscle fiber characteristics from all these different sites were compared. It is clear that in the rhesus monkey at least, muscle fiber characteristics are dependent on the vertebral level although not necessarily on the side of the vertebral column.

Movement is life

Starting in utero, where movement is essential for the development of normal joints, a pattern is set up which is repeated throughout life. The evolution of the species is mirrored in the development of the individual, and movement, exercise and neuromuscular development form a central theme. The major skeletal changed are related to the changes in age. The emergence of disease patterns, the progress of the ageing process and the factor influencing morbidity and mortality are discussed. The role of the therapist as an expert in exercise, both prophylactic and therapeutic, is emphasized and particular attention is paid to the widening opportunities outside the sphere of the traditional clinical setting.

Role of selected muscles of respiration as influenced by posture and tidal volume

Studies of the activity of accessory respiratory muscles were conducted in 30 normal subjects (15 male and 15 female subjects, age 5 to 62 years). Electromyograms were recorded over the right serratus anterior muscle and the adjacent sixthe intercostal space, and the results were correlated with tidal volume. Phasic respiratory activity in the serratus anterior muscle was detected in every subject but was markedly affected by the prevailing posture and level of ventilation (appearing at mean tidal volumes equivalent to 60.5 percent of vital capacity when subjects were standing relaxed, and equivalent to 35.2 percent of vital capacity when subjects were seated, leaning forward with elbows supported). The activity was predominantly inspiratory in timing but in some subjects extended into early expiration. No significant differences were noted in subjects of different ages, sex, height, or weight. Similar results were recorded from the inspiratory intercostal muscle. On the basis of these findings, we conclude that, contrary to reports, the serratus anterior muscle should be classified as an accessory muscle of respiration, at least at increased levels of ventilation, and that its activity is most pronounced in postures that place the muscles' origin in an advantageous position for moving the ribs.