Reproducibility of kinematic measures of the thoracic spine, lumbar spine and pelvis during fast running

This study evaluated the reproducibility of the angular rotations of the thoracic spine, lumbar spine, pelvis and lower extremity during running. In addition, the study compared kinematic reproducibility between two methods for calculating kinematic trajectories: a six degrees of freedom (6DOF) approach and a global optimisation (GO) approach. With the first approach segments were treated independently, however with GO approach joint constraints were imposed to stop translation of adjacent segments. A total of 12 athletes were tested on two separate days whilst running over ground at a speed of 5.6ms(-1). The results demonstrated good between-day reproducibility for most kinematic parameters in the frontal and transverse planes with typical angular errors of 1.4-3°. Acceptable repeatability was also found in the sagittal plane. However, in this plane, although kinematic waveform shape was preserved between testing session, there were sometimes shifts in curve offset which lead to slightly higher angular errors, typically ranging from 1.9° to 3.5°. In general, the results demonstrated similar levels of reproducibility for both computational approaches (6DOF and, GO) and therefore suggest that GO may not lead to improved kinematic reproducibility during running.

Alcohol misuse in patients with psoriasis: identification and relationship to disease severity and psychological distress

BACKGROUND

Moderate to severe psoriasis is associated with increased alcohol intake and excessive mortality from alcohol-related causes. Alcohol biomarkers provide an objective measure of alcohol consumption. Carbohydrate-deficient transferrin (CDT) is the single most sensitive and specific alcohol biomarker.

OBJECTIVES

To assess alcohol consumption in a cohort of patients with moderate to severe psoriasis using standard alcohol screening questionnaires and biomarkers. We investigated whether there was an association between alcohol intake, anxiety, depression and disease severity.

METHODS

Consecutive patients with chronic plaque psoriasis were recruited and completed a range of anonymized assessments. Psoriasis severity, anxiety and depression, and the impact of psoriasis on quality of life were assessed. Alcohol screening questionnaires were administered. Blood specimens were taken and γ-glutamyltransferase (γGT) and CDT were measured.

RESULTS

A total of 135 patients completed the study. Using validated questionnaires, between 22% and 32% had difficulties with alcohol. Seven per cent had CDT > 1·6% indicating a heavy alcohol intake. The Alcohol Use Disorders Identification Test (AUDIT) questionnaire was superior to other validated questionnaires in detecting alcohol misuse. There were no significant associations between measures of excessive alcohol consumption and disease severity. Excessive alcohol intake as measured by the CAGE questionnaire was associated with increased depression (P = 0·001) but other measures of alcohol excess did not correlate with psychological distress. Men had significantly more difficulties with alcohol than women (P < 0·001).

CONCLUSION

Alcohol misuse is common in patients with moderate to severe psoriasis. Screening with the AUDIT questionnaire and CDT may allow the identification of patients who are misusing alcohol and allow appropriate intervention.

Alcohol consumption and psychological distress in patients with psoriasis

BACKGROUND

Psoriasis has been associated with excessive alcohol consumption and psychological distress.

OBJECTIVES

To investigate the level of alcohol use in a psoriasis population and to determine whether alcohol consumption is linked to psychological distress in patients with psoriasis.

METHODS

Ninety-five patients with chronic plaque psoriasis completed validated questionnaires designed to assess psychological distress, current and past alcohol consumption and self-reported physical severity of psoriasis.

RESULTS

Using different measures of alcohol consumption, between 17% and 30% of patients were classified as having difficulties with alcohol. Thirteen per cent and 18% of patients with psoriasis believed that they had a current or past drinking problem, respectively. There was a modest but significant association between levels of anxiety and depression and weekly alcohol consumption (r = 0.29, P < 0.01 and r = 0.24, P = 0.03, respectively). Those patients who believed that they had an alcohol problem had higher levels of anxiety (P = 0.03), depression (P < 0.01) and psoriasis-associated disability (P = 0.04). There was a modest but significant association between physical severity of psoriasis and weekly alcohol consumption (r = 0.27, P = 0.02).

CONCLUSIONS

A significant minority of patients with psoriasis consumes excessive alcohol. Patients with psoriasis should be assessed for excessive alcohol use and appropriate interventions initiated. Further studies are required to investigate whether such interventions are effective in combating alcohol abuse and in improving the psychological and physical aspects of psoriasis.

Rehabilitation for hamstring injuries

BACKGROUND

Hamstring injuries are a common musculoskeletal disorder, particularly amongst athletes. Many factors have been associated with these injuries including motor control and strength, soft tissue length and postural alignment. Well established rehabilitation protocols are commonly used in the treatment of this condition, but their effectiveness remains questionable.

OBJECTIVES

To evaluate the effectiveness of all rehabilitation strategies employed to promote the return to full strength, range of movement and function of those individuals presenting with all forms of hamstring injury, regardless of site, severity, onset or level of chronicity.

SEARCH STRATEGY

We searched the Cochrane Bone, Joint and Muscle Trauma Group Specialised Register (to January 2006), CENTRAL (The Cochrane Library 2006, Issue 1), MEDLINE, EMBASE, PEDro - The Physiotherapy Evidence Database, CINAHL, AMED, SPORTDiscus and reference lists of articles. Date of last search: February 2006. No language restrictions were applied.

SELECTION CRITERIA

Selected studies were randomised controlled trials or randomised comparative trials, investigating the effect of at least one rehabilitation strategy, in isolation or combination with another, compared to another strategy or control, performed on individuals presenting with hamstring injuries.

DATA COLLECTION AND ANALYSIS

Two review authors performed study selection. Three review authors performed data extraction and methodological quality assessment. Any disagreement was resolved by discussion.

MAIN RESULTS

Three trials were included in the review. The main results present limited evidence over a range of techniques and patient groups. There was no trial of intervention versus rest. Only two small trials compared times to return to normal function, and definition of this outcome varied between studies. The first trial, involving 80 athletes, suggested stretching four times a day instead of just once and resulted in a statistically significant reduction in time to return to normal function (mean difference (MD) -1.8 days, 95% confidence interval (CI) -2.15 to -1.45, P < 0.001). The second trial, with 24 participants from a diverse sporting background, found that progressive agility and trunk stabilization exercises and icing did not achieve a statistically significant reduction in time to return to full function when compared to stretching and progressive resistance exercises and icing (MD -14.5 days, 95% CI -30.64 to 1.64, P = 0.08). The third trial, conducted with 20 non-athletes, suggests there was no evidence of effect with manual therapy on soft tissue length (MD 10.4 degrees, 95% CI -3.19 to 23.99 in favour of manual therapy, P = 0.13), on hamstring muscle peak torque (MD -0.7 foot-pounds, 95% CI -18.45 to 17.05 in favour of control, P = 0.94), or on quadriceps femoris muscle peak torque (MD -22.1 foot-pounds, 95% CI -59.00 to 14.80 in favour of control, P = 0.24) following a single treatment.

AUTHORS' CONCLUSIONS

There is limited evidence to suggest that rate of recovery can be increased with an increased daily frequency of hamstring stretching exercises. Consideration should be given to the lumbar spine, sacroiliac and pelvic alignment and postural control mechanisms when managing hamstring injuries. Lumbar stability and pelvic motor control may also be factors in reducing the rate of recurrence of hamstring injury. Until further evidence is available, current practice and widely published rehabilitation protocols cannot either be supported or refuted.

The flatness of Siemens linear accelerator x-ray fields

The primary definer for Siemens MXE and MDX linear accelerators projects a circular opening with a radius of 25 cm at 100 cm from the target. Our measurements of photon beam profiles, however, indicate that the photon fluence drops to 95% of the central axis value at a radius of 18 cm. The flattening filter for these machines projects a flattened field size that is much smaller than the primary definer would allow. The clinical implications of this mismatch for large rectangular fields and for fields defined by asymmetric jaws are discussed and solutions are considered. A large field flattener was designed for our Siemens MXE 6 MV beam using Monte Carlo simulation of the treatment head and water phantom. The accuracy required of source and geometry details for dose distributions calculation is presented. The key parameters are the mean energy and focal spot size of the electron beam incident on the exit window, the material composition, and thickness profile of the exit window, target, flattener, and primary collimator, and the position of the primary collimator relative to the target. Profiles were more sensitive than central axis depth doses to simulation details. The beam energy and primary collimator position were selected to achieve good agreement between measured and calculated dose distributions. The flattener we designed with Monte Carlo was machined from brass and mounted on our MXE treatment unit. Measurements demonstrate that the large field flattener extends the useful radius of the field out to 22 cm, right into the penumbra cast by the primary collimator.

Randomized blinded study of aprotinin infusion for liver crush injuries in the pig model

Repeat exploratory laparotomies for intra-abdominal bleeding in patients who sustain severe blunt intra-abdominal trauma are common. Reexploration usually reveals no single site of bleeding and the abdomen is closed with laparotomy pad packing, with a presumed diagnosis of coagulopathy. These postoperative coagulational defects may be the result of dilution, consumption, dysfunction, or acquired defects of either the coagulation, fibrinolytic, or platelet systems. The liver plays a major role in the balance of hemostatic systems, and this balance is disrupted by liver trauma. This study investigates the use of intravenous aprotinin, a naturally occurring serine protease inhibitor, in a pig liver crush model to evaluate its effectiveness in reducing intra-abdominal bleeding in experimentally induced shock and non-shock states.

Exceptional increases in electron cone output as the backup diaphragms are opened

Some linac manufacturers provide cones for defining circular electron fields. During commissioning of one of our new radiotherapy units, we noted that the output of these cones has a strong dependence on the diaphragm opening that precedes the cone. In particular, for the 8 MeV beam, the output of a 3 cm diameter cone increased by more than a factor of 2 as the diaphragm was opened from 5 x 5 to 20 x 20 cm. One concludes that the particular mechanical design results in an output factor dependency that is exceptional when compared to the data presented in standard texts such as Khan's "The Physics of Radiation Therapy." The importance of quality assurance and communications with the manufacturer is underscored by this example.

Implementation of multiple isocentre treatment for dynamic radiosurgery

Radiosurgery using the dynamic rotation technique with a single isocentre was introduced at the Toronto-Bayview Regional Cancer Centre (T-BRCC) in 1988. Since then, over 100 patients have been treated. It was soon recognized that 25-30% of patients were referred with either non-spherical lesions or multiple lesions located sufficiently close together that consideration had to be given to the overlapping dose distributions throughout the treated volume. To treat these more complex targets a multiple isocentre technique was developed which also took account of these effects and the resulting normalization problem. This technique was implemented in September 1992. Comparisons between calculated doses and actual doses delivered have been undertaken using a spherical phantom containing radiochromic film. Measured dose distributions agreed with the planned distributions to within +/- 1 mm. The effect of multiple isocentres on the penumbra of dose distributions has been examined. The methods adopted for the normalization of treatment plans and clinical examples illustrating the application of the multiple isocentre technique are presented.

The use of radiochromic film in treatment verification of dynamic stereotactic radiosurgery

Standard silver-based films are usually too sensitive to be used as direct indicators of dose in dynamic radiosurgery because of optical saturation. This paper describes the use of a new radiochromic film to measure 6-MV radiosurgery doses and dose distributions in a head phantom. Dose calibration of the radiochromic film was performed in the range of 2.3-50.2 Gy using light of 632- and 530-nm wavelengths. Radiosurgery dose distributions were measured using the radiochromic film in a head phantom undergoing the same treatment as a patient, and were compared with the planned distributions. For an example case (nominal 2.0-cm-diam cone), film measurement verified the calculated dose distribution in one plane. The simple measurement technique described led to experimental uncertainties of +/- 0.1 cm for the 90% and 50% isodose lines, +/- 0.3 cm for the 20% line, and +/- 0.5 cm for the 10% line. Isocenter dose was measured with an uncertainty of +/- 3%. Refinements to the technique should allow more precise measurements. It is concluded that the radiochromic film, with some limitations, is a convenient and useful tool for dynamic radiosurgery quality assurance.

Ytterbium-169: calculated physical properties of a new radiation source for brachytherapy

Seeds containing radioactive Ytterbium-169 (169Yb) have recently been manufactured for possible application to brachytherapy. Ytterbium-169 emits photons with an average energy of 93 keV (excluding energies less than 10 keV), and decays with a half-life of 32 days. Analytic and Monte Carlo computations have been used to predict physical quantities useful in treatment planning and radiation protection. Analytic calculations based on the primary photon spectrum of 169Yb (excluding energies less than 10 keV) yield an air-kerma rate constant of 0.0427 cGy cm2 h-1 MBq-1, and an exposure rate constant of 1.80 R cm2 mCi-1 h-1 for this radionuclide. Calculated fmed factors are 0.922 cGy/R for soft tissue and 2.12 cGy/R for bone. The first half-value layer in lead is 0.2 mm; the first tenth-value layer is 1.6 mm. Using Monte Carlo simulations, the relative dose distributions around 169Yb seeds (Amersham, prototypes 4 and 5) are provided, and are then compared with those around an 125I seed (3M model 6702). The 169Yb seeds produce more isotropic dose distributions, and for permanent implants, can deliver it at a greater initial dose rate. A value of 1.19 cm-2 was also calculated for the specific dose constant D0, a value which is applicable to both seed types. Radiation protection is not as easily achieved for permanent implants with 169Yb because of the higher energy emissions (vs 125I). However, for temporary implants, Ytterbium-169 may prove to be a useful substitute for 192Ir or 137Cs because of its relatively lower energy emissions. It is concluded that 169Yb merits further investigation, including dosimetry, radiobiological, and clinical studies.

Properties of a tyrosine protein kinase from calf thymus. Response to ionic strength and divalent cations

A tyrosine protein kinase activity has been partially purified from calf thymus using the phosphorylation of the tyrosine-containing peptide angiotensin I as an assay. Detergent extracts of calf thymus possessed only low levels of specific peptide phosphorylating activity when assayed at low ionic strength. The inclusion of NaCl at a concentration of 2 M stimulated endogenous tyrosine protein kinase activity, while the activity of other endogenous kinases was inhibited. This sensitivity to NaCl was retained following partial purification of the enzyme. The phosphorylation of other substrates such as casein or the R-R-SRC peptide (Arg-Arg-Leu-Ile-Glu-Asp-Ala-Glu-Tyr-Ala-Ala-Arg-Gly) by the tyrosine protein kinase was less sensitive to NaCl. Phosphorylation of the PK-1 peptide (Leu-Arg-Arg-Ala-Ser-Leu-Gly) by the purified catalytic subunit of cAMP-dependent protein kinase was inhibited by NaCl. The effect of NaCl on angiotensin I phosphorylation could be mimicked by KCl or sodium acetate. The principal effect of NaCl was to increase the Vmax of the enzyme for the phosphorylation of angiotensin I. At low ionic strength, Mn2+ and Co2+ were the preferred required divalent cations. At elevated NaCl concentrations Mg2+ was preferred, with half-maximal activation occurring at 35 mM Mg2+. By conducting peptide phosphorylation assays in the presence of elevated levels of Mg2+ and NaCl, tyrosine protein kinase activity can readily be detected in extracts from cell lines that express low levels of the enzyme.

Cytochemical and biochemical identification of lysosomes in Cryptococcus neoformans

Normaski optics, fluorescence and electron microscopy were employed to demonstrate the occurrence of lysosomes in capsulated, enztmatically decapsulated, and dewalled cells of a human isolate of Cryptococcus neoformans. Fluorescent studies, using acridine orange as a lysosomal indicator, revealed the presence of variously sized, spherical, reddish-orange fluorescing bodies. Electron microscopy studies demonstrated the presence of acid phosphatase (AP), a lysosome marker enzyme, in single-membrane bound organelles. Lysosomes were removed from dewalled cells and separated by differential centrifugation on ficoll gradients. That fraction indicating the highest assay for AP was centrifuged at high speed, and the resulting pellet was fixed for electron microscopy and stained by the Gomori procedure for AP. Sections of the pellets revealed AP stained vesicles of the same size range as those within intact cells.