Dexterous helical magnetic robot for improved endovascular access.

Treating vascular diseases in the brain requires access to the affected region inside the body. This is usually accomplished through a minimally invasive technique that involves the use of long, thin devices, such as wires and tubes, that are manually maneuvered by a clinician within the bloodstream. By pushing, pulling, and twisting, these devices are navigated through the tortuous pathways of the blood vessels. The outcome of the procedure heavily relies on the clinician's skill and the device's ability to navigate to the affected target region in the bloodstream, which is often inhibited by tortuous blood vessels. Sharp turns require high flexibility, but this flexibility inhibits translation of proximal insertion to distal tip advancement. We present a highly dexterous, magnetically steered continuum robot that overcomes pushability limitations through rotation. A helical protrusion on the device's surface engages with the vessel wall and translates rotation to forward motion at every point of contact. An articulating magnetic tip allows for active steerability, enabling navigation from the aortic arch to millimeter-sized arteries of the brain. The effectiveness of the magnetic continuum robot has been demonstrated through successful navigation in models of the human vasculature and in blood vessels of a live pig.

Highlights and discoveries from the Chandra X-ray Observatory.

Within 40 years of the detection of the first extra-solar x-ray source in 1962, NASA's Chandra X-ray Observatory has achieved an increase in sensitivity of 10 orders of magnitude, comparable to the gain in going from naked-eye observations to the most powerful optical telescopes over the past 400 years. Chandra is unique in its capabilities for producing sub-arcsecond x-ray images with 100-200 eV energy resolution for energies in the range 0.08 < E < 10 keV, locating x-ray sources to high precision, detecting extremely faint sources, and obtaining high-resolution spectra of selected cosmic phenomena. The extended Chandra mission provides a long observing baseline with stable and well-calibrated instruments, enabling temporal studies over timescales from milliseconds to years. In this report we present a selection of highlights that illustrate how observations using Chandra, sometimes alone, but often in conjunction with other telescopes, have deepened, and in some instances revolutionized, our understanding of topics as diverse as protoplanetary nebulae; massive stars; supernova explosions; pulsar wind nebulae; the superfluid interior of neutron stars; accretion flows around black holes; the growth of supermassive black holes and their role in the regulation of star formation and growth of galaxies; impacts of collisions, mergers, and feedback on growth and evolution of groups and clusters of galaxies; and properties of dark matter and dark energy.

The influence of microgravity on Euglena gracilis as studied on Shenzhou 8.

The German Aerospace Center (DLR) enabled German participation in the joint space campaign on the unmanned Shenzhou 8 spacecraft in November 2011. In this report, the effect of microgravity on Euglena gracilis cells is described. Custom-made dual compartment cell fixation units (containing cells in one chamber and fixative - RNA lysis buffer - in another one) were enclosed in a small container and placed in the Simbox incubator, which is an experiment support system. Cells were fixed by injecting them with fixative at different time intervals. In addition to stationary experiment slots, Simbox provides a 1 g reference centrifuge. Cell fixation units were mounted in microgravity and 1 g reference positions of Simbox. Two Simbox incubators were used, one for space flight and the other as ground reference. Cells were fixed soon after launch and shortly before return of the spaceship. Due to technical problems, only early in-flight samples (about 40 min after launch microgravity and corresponding 1 g reference) were fully mixed with fixative, therefore only data from those samples are presented. Transcription of several genes involved in signal transduction, oxidative stress defence, cell cycle regulation and heat shock responses was investigated with quantitative PCR. The data indicate that Euglena cells suffer stress upon short-term exposure to microgravity; various stress-induced genes were up-regulated. Of 32 tested genes, 18 were up-regulated, one down-regulated and the rest remained unaltered. These findings are in a good agreement with results from other research groups using other organisms.

Muscle strength of the lumbar spine in different sports.

BACKGROUND: The ability to stabilize the body center (core stability) against dynamic movements of the extremities and capability to absorb repetitive loading forces in the trunk play a crucial role in any professional sport specific performance. OBJECTIVE: The aim our cross sectional level of evidence 3 study was to determine, if athletes of different sport disciplines showed specific trunk strength profiles and if these were different from a control group. METHODS: 20 ironman triathletes, 18 amateur volleyball and 18 amateur soccer players were tested for their individual isometric strength of the lumbar spine in three planes of motion using a standartized test device. RESULTS: The test profile revealed similar strength parameters for extension and lateral flexion to the left in each of the 3 study groups tested. The lateral flexion to the right was significantly stronger than in the control group (soccer > volleyball > triathlon). In all 3 groups, weaknesses were found in the abdominal musculature, showing highly significant differences in flexion and bilateral rotation compared to the control group (p=0.001). CONCLUSIONS: Our study shows that sports specific training for triathlon, as well as the team sports soccer and volleyball, does not lead to balanced trunk musculature and core stability. In consequence predisposing injury and muscle dysbalane can trigger pain syndromes.

[Electromagnetic navigation of transpedicular punctures: more precise than the standard?]. / Elektromagnetische Navigation transpedikulärer Punktionen: Präziser als der Standard?

AIM: Before clinical implementation of an approved electromagnetic tracking system (CAPPA IRAD EMT) an experimental trial was performed to investigate the accuracy of the system and its safety in application for transpedicular vertebral punctures in comparison to the classical fluoroscopic method. MATERIAL AND METHODS: A total of 110 transpedicular punctures were performed bilaterally using 11 vertebrae of 5 realistic artificial phantoms and 1 pedicle was punctured with the conventional technique using c-arm fluoroscopy and the other with the electromagnetic tracking system. As a target a radiopaque non-ferromagnetic marker was implanted bilaterally in the anterior wall of the vertebrae. For evaluation of the precision the distance from the end of the puncture to the target and the gradual deviation of the actual channel from the ideal trajectory were assessed in three-dimensional computer tomography. Calculations and statistical analysis were performed according to the Wilcoxon test by means of SPSS 16.0.1 for Windows. RESULTS: The mean distance from the target was 6.6 mm (± 3.9 mm standard deviation SD) with electromagnetic navigation compared to 3.2 mm (± 2.8 mm SD) with fluoroscopic assistance and the mean aberration from the ideal trajectory was 18.4° (± 4.6° SD) compared to 6.5° (± 3.5° SD), respectively. The difference of accuracy was highly significant regarding both parameters (p < 0.001). CONCLUSIONS: The minimum requirement for accuracy of transpedicular punctures could not be achieved with electromagnetic navigation. Unless proven otherwise, the lack of accuracy is attributed to unstable referencing. Despite evidence of successful employment for soft tissue punctures the system cannot currently be recommended for osseous applications of the spine.

Discovery of powerful gamma-ray flares from the Crab Nebula.

The well-known Crab Nebula is at the center of the SN1054 supernova remnant. It consists of a rotationally powered pulsar interacting with a surrounding nebula through a relativistic particle wind. The emissions originating from the pulsar and nebula have been considered to be essentially stable. Here, we report the detection of strong gamma-ray (100 mega-electron volts to 10 giga-electron volts) flares observed by the AGILE satellite in September 2010 and October 2007. In both cases, the total gamma-ray flux increased by a factor of three compared with the non-flaring flux. The flare luminosity and short time scale favor an origin near the pulsar, and we discuss Chandra Observatory x-ray and Hubble Space Telescope optical follow-up observations of the nebula. Our observations challenge standard models of nebular emission and require power-law acceleration by shock-driven plasma wave turbulence within an approximately 1-day time scale.

In vivo quantification of lead in bone with a portable x-ray fluorescence system--methodology and feasibility.

This study was conducted to investigate the methodology and feasibility of developing a portable x-ray fluorescence (XRF) technology to quantify lead (Pb) in bone in vivo. A portable XRF device was set up and optimal settings of voltage, current, and filter combination for bone lead quantification were selected to achieve the lowest detection limit. The minimum radiation dose delivered to the subject was calculated by Monte Carlo simulations. An ultrasound device was used to measure soft tissue thickness to account for signal attenuation, and an alternative method to obtain soft tissue thickness from the XRF spectrum was developed and shown to be equivalent to the ultrasound measurements (intraclass correlation coefficient, ICC = 0.82). We tested the correlation of in vivo bone lead concentrations between the standard KXRF technology and the portable XRF technology. There was a significant correlation between the bone lead concentrations obtained from the standard KXRF technology and those obtained from the portable XRF technology (ICC = 0.65). The detection limit for the portable XRF device was about 8.4 ppm with 2 mm soft tissue thickness. The entrance skin dose delivered to the human subject was about 13 mSv and the total body effective dose was about 1.5 µSv and should pose minimal radiation risk. In conclusion, portable XRF technology can be used for in vivo bone lead measurement with sensitivity comparable to the KXRF technology and good correlation with KXRF measurements.

Polymorphisms of caffeine metabolism and estrogen receptor genes and risk of Parkinson's disease in men and women.

Caffeine intake has been associated with a decreased risk of Parkinson's disease (PD) in men but the effect in women is less clear, and appears to be modified by use of post-menopausal estrogens. In a nested case-control study within the Nurses Health Study (NHS) and the Health Professionals Follow-up Study (HPFS), we examined associations between single nucleotide polymorphisms (SNPs) of caffeine metabolizing genes (CYP1A2 and NAT2) and estrogen receptors (ESR1 and ESR2), their interaction with caffeine intake and hormone replacement therapy (PMH) use (collected prospectively) and risk of PD. We matched 159 female cases to 724 controls and 139 male cases to 561 controls on birth year, source of DNA (blood or buccal smear), age and sex. The CYP1A2 rs762551 polymorphism (lower enzyme inducibility) was marginally associated with an increased risk of PD (RR, for increasing number of minor alleles=1.34; 95% CI 1.02, 1.78 in women, but not in men. None of the NAT2 (classified as slow vs. fast acetylator), ESR1 or ESR2 polymorphisms were significantly associated with an altered risk of PD. Marginally significant interactions were observed between caffeine intake and the ESR1 polymorphism rs3798577 (p=0.07) and ESR2 polymorphism rs1255998 (p=0.07). The observed increased risk of PD among female but not male carriers of the rs762551 polymorphism of CYP1A2 and the interactions of caffeine with ESR1 rs3798577 and ESR2 rs1255998 may provide clues to explain the relationship between gender, caffeine intake, estrogen status and risk of PD and need to be replicated.

Persistent organochlorine pesticides in serum and risk of Parkinson disease.

BACKGROUND: Pesticides have been implicated as likely environmental risk factors for Parkinson disease (PD), but assessment of past exposure to pesticides can be difficult. No prior studies of pesticide exposure and PD used biomarkers of exposure collected before the onset of PD. Our investigation examined the association between prospective serum biomarkers of organochlorine pesticides and PD. METHODS: We conducted a nested case-control study within the Finnish Mobile Clinic Health Examination Survey, with serum samples collected during 1968-1972, and analyzed in 2005-2007 for organochlorine pesticides. Incident PD cases were identified through the Social Insurance Institution's nationwide registry and were confirmed by review of medical records (n = 101). Controls (n = 349) were matched for age, sex, municipality, and vital status. Adjusted odds ratios (ORs) of PD were estimated using logistic regression. RESULTS: Little association emerged with a summary score of the 5 organochlorine pesticides found at high levels, and only increasing dieldrin concentrations trended toward a higher risk of PD (OR per interquartile range [IQR] 1.28, 95% confidence interval [CI] 0.97-1.69, p = 0.08). Because of possible strong confounding by cigarette smoking among smokers, we ran additional analyses restricted to never smokers (n = 68 cases, 183 controls). In these analyses, increasing dieldrin concentrations were associated with increased odds of PD (OR per IQR 1.95, 95% CI 1.26-3.02, p = 0.003). None of the other organochlorine pesticides were associated with PD in these analyses. CONCLUSIONS: These results provide some support for an increased risk of Parkinson disease with exposure to dieldrin, but chance or exposure correlation with other less persistent pesticides could contribute to our findings.

[Influence of disc prosthesis position on segmental motion in the lumbar spine]. / Einfluss der Position einer lumbalen Bandscheibenprothese auf das segmentale Bewegungsverhalten.

AIM OF THE STUDY: Total disc arthroplasty is reported to maintain segmental motion. From finite element studies a rather posterior and central implantation of the prosthesis is recommended. However, there is yet no in vitro study with cadaveric specimens investigating the topic of implant positioning. METHODS: Ten human lumbar spines were subjected to biomechanical testing. Flexion/extension and side-bending moments were applied from 2.5-7.5 Nm on a spine load simulator. First, the intact specimens were tested in 3 load cycles while motion was monitored with regard to the facet joints under different loads by an ultrasound-based system. An unconstrained total disc prosthesis was then implanted in a central position and the different load cycles were repeated. Finally the implant was positioned in a decentral position with an average offset of 6.2 mm for repetitive data acquisition. RESULTS: Comparison of the facet joint motion in central and eccentric prosthesis positions resulted in the following averaged differences. During flexion of the lumbar spine an average difference of the reference point excursions of 0.38 mm was recorded on the ipsilateral facet joint with reference to the decentral position. For extension, the difference was 0.33 mm on average, for right side bending a difference of 0.63 mm was recorded while left side bending resulted in an average difference of 0.24 mm. The deviation of the reference markers on the contralateral facet joint showed the following average differences: for flexion 0.23 mm and for extension 0.54 mm, respectively. For side bending right/left the differences amounted to 0.18 mm and 0.39 mm. With regard to segmental motion there was no statistically significant difference for both the ipsilateral (p = 0.0564) and the contralateral (p = 0.2593) reference marker. CONCLUSIONS: The comparison of the segmental motion after central and decentral implantation of a lumbar total disc prosthesis reveals differences that have, nevertheless, no statistical significance. However, for clinical use it is recommended to strive for a central position of the implant.

[Biomechanical analysis of lumbar spine after implantation of a disk prosthesis and supplementary spinal fusion for management of complications]. / Biomechanische Analyse der Lendenwirbelsäule nach Implantation einer Bandscheibenendoprothese sowie ergänzender Spondylodese als Komplikationsmanagement.

STUDY DESIGN: The aim of our investigations was to study the question as to what extent the mono- and multisegmental mobility of the lumbar spine (LS) differs after implantation of a disc prosthesis (DP) and if, in case of postoperative complications (dislocation or migration of the disc prosthesis), a sufficient stability of the motion segment can be achieved with a spinal fusion. To answer these questions we examined in corpse the mobility of the LS before and after DP implantation as well as after spinal fusion by using a load simulator for mobility and stability investigations of the lumbar spine. METHOD: After radiological exclusion of higher degenerative changes (X-ray in two planes) and exclusion of high-grade osteoporosis by using a pQ-CT scan with measurement of the bone mineral density (T score > -3.0), the first step was the multisegmental measurement of the thirteen unfixated LS specimens without DP by automatic electromechanical load-bearing. The measurements of mobility of the LS were done in flexion, extension, side-bending and side-rotation with a reproducible load of 10 Nm. The analysis of the movements during flexion and extension as well as side-bending and side-rotation were done by an ultrasonic detection system (zebris). In the second step the excursions were measured after implantation of the DP in L3/4 and in the third step after additional dorsal spinal fusion. RESULTS: After implantation of the artificial disc in L3/4 the mobility in side-bending and side-rotation increases in comparison to the LS without surgery. For side-bending we found an increasing amount up to +74 % for the single motion segment L3/4 and +3 % for the total LS, respectively, for the side-rotation an increase of mobility up to +72 % for the single motion segment L3/4 and +30 % for the total LS. On the other hand a decreased mobility of -11 % for flexion and extension was found with an artificial disc in comparison to the lumbar spine. After additional dorsal spinal fusion of L3/4 the mobility obviously decreases in all directions (flexion/extension -74 %, side-bending -75 %, side-rotation -51 %). CONCLUSION: The DP preserves (flexion/extension) and, respectively, improves (side-rotation/side-bending) the mobility of the LS. In cases of complications like dislocation or migration of the DP and secondary degenerative changes, the dorsal spinal fusion with restricted movements of the LS afterwards is a possible treatment solution.

[Hip centralising forces of the iliotibial tract with various femoral neck angles]. / Die hüftkopfzentrierenden Kräfte des Tractus iliotibialis bei variierendem Schenkelhalswinkel.

AIM: Concerning the biomechanical properties of the iliotibial tract different opinions can be found in the literature. Due to this fact it was the aim of this study to take measurements about the hip centralising forces of the iliotibial tract in a neutral position as well as in abduction, adduction and flexion of the hip joint at different femoral neck angles by using a custom-made hip prosthesis. METHOD: By using a custom-made measuring endoprothesis with the capability for adjusting different femoral neck angles and lengths and, furthermore, by measuring the intra- and subligamentous forces at the height of the greater trochanter, we measured the forces for validating the influence of the iliotibial tract for hip joint centralisation. RESULTS: By increasing the CCD angle (coxa valga) a higher load on the hip joint results. By decreasing the CCD angle (coxa vara) a lowering of the coxalfemoral load results. Flexion of the knee joint leads to a decrease of the iliotibial tract tension. By extension of the knee joint and resulting tightening of the iliotibial tract, a triplication of the forces at the femoral neck was measured. Flexion of the hip joint exerted a ventralising of the iliotibial tract with an initial decrease of the centralising hip forces. Subligamentous measurement of the iliotibial tract showed increasing forces upon adduction as well as decreasing forces upon abduction of the hip joint. In the investigations about the forces with various femoral neck lengths, we saw a considerable increase by lengthening the femoral neck and resulting higher forces in the acetabulum. CONCLUSION: The clinical relevance of these results concerns the predictability of the in- or decreasing tension band wiring effect of the iliotibial tract in correlation to the CCD angle and the direction of motion of the hip joint. The measurements give the clinical users a benchmark for the expected subligamentous forces of the iliotibial tract and the resulting hip centralising forces. The influence of the lengthening of the femoral neck for the hip centralising forces clarifies the importance of the iliotibial tract when planning displacement osteotomies or hip joint replacement.

[Successful surgical intervention for lumbar tuberculous spondylodiscitis in spite of delayed indication - 5 year follow-up]. / Erfolgreiche operative Sanierung einer tuberkulösen Spondylodiszitis der Lendenwirbelsäule trotz verzögerter Indikation - 5-Jahres-Ergebnis.

Tuberculosis constitutes an important clinical entity with 90 million new infections worldwide during the last decade. 10 % of these infections affect osseous structures based on haematogenous spread. Therefore, tuberculous spondylodiscitis remains a major illness in orthopaedics which needs to be considered in cases of unspecific back pain. Pathognomonic characteristics are absent and clinical, chemical and radiological parameters are not reliable. The consequences of a delayed surgical intervention are discussed based on a case report with 5 year follow-up. Both adequate early CT and MRI scans and identification of the pathogen are essential in order to plan the therapy. Final re-evaluation of a conservative treatment regime needs to be done no later than six to eight weeks depending on the clinical constellation. Persistent or progressive spondylodiscitis with osseous destructions or neurological deficits demands a radical surgical intervention.

Prospective study of chemical exposures and amyotrophic lateral sclerosis.

BACKGROUND: Although environmental toxins, including pesticides, are suspected of contributing to the risk of amyotrophic lateral sclerosis (ALS), no data exist from large prospective investigations. This study assessed the association between exposure to chemicals and risk of ALS in a prospective cohort study. METHODS: The relation between self-report of regular exposure to 11 different chemical classes or x rays and ALS mortality among over 1 million participants in the American Cancer Society's Cancer Prevention Study II was prospectively assessed. Follow-up from 1989 through 2004 identified 617 deaths from ALS among men and 539 among women. Adjusted rate ratios (RR) were calculated using Cox proportional hazards. RESULTS: The RR for ALS mortality among individuals exposed to pesticides/herbicides compared with that among unexposed individuals was 1.07 (95% CI 0.79 to 1.44), but somewhat higher after excluding those with missing duration of pesticides exposure (RR 1.44; 95% CI 0.89 to 2.31; p = 0.14). A non-significant increase in ALS mortality was found among individuals who reported exposure to formaldehyde (RR 1.34; 95% CI 0.93 to 1.92). Excluding those with a missing duration of formaldehyde exposure, the RR was 2.47 (95% CI 1.58 to 3.86), and there was a strongly significant dose-response relation with increasing years of exposure (p trend = 0.0004). CONCLUSIONS: There was little evidence for any association between pesticides/herbicide exposure and ALS. In contrast, evidence was found, suggesting an increased risk of ALS with formaldehyde exposure. Because of the longitudinal design, this result is unlikely to be due to bias, but it should nevertheless be interpreted cautiously and needs to be verified independently.

[Intravertebral pressure during vertebroplasty - an in-vitro study]. / Intravertebrale Druckentwicklung bei der Vertebroplastie - Eine anatomische In-vitro-Untersuchung.

INTRODUCTION: Extravasation of bone cement into the vertebral venous system during cement injection has been reported to be a major complication of percutaneous vertebroplasty. Therefore, high injection pressures during cement application into the fractured vertebral body are considered as one possible cause of cement leakage or extravasation. The aim of the current study was to measure the increase in intravertebral pressure caused by cement injection during vertebroplasty compared to the baseline venous pressure for the ascending lumbar vene. MATERIAL AND METHODS: In context of a cadaver study of 19 unfixed lumbar cadaver spines (L2-L5) [9 female, 10 male, 72 +/- 4.1 years] 19 vertebroplasties have been performed under operative conditions through a transpedicular approach. A manometer was placed in the lateral corticalis of each vertebral body for dynamic pressure measurement during 4 cement application cycles. Average and maximal intravertebral pressures as well as the average intravertebral pressure over the time of cement application ["area under the curve" (AUC)] were calculated. RESULTS: Average intravertebral pressure (10.9 +/- 12.6 kPa [min.: - 15.2 +/- 24.7 kPa; max.: 56.1 +/- 70.1 kPa]) showed a 13.6-fold increase compared to the baseline venous pressure for the ascending lumbar vein and a 70-fold increase compared to maximal pressure. During the 4 cement application cycles a continuous increase of the average intravertebral pressure over the application cycle (AUC) occurred. CONCLUSION: The 13.6-fold increase in intravertebral body pressure caused by cement injection during percutaneous vertebroplasty in comparison to the baseline venous pressure for the ascending lumbar vein might be one possible cause of the high rate of extravasation of bone cement reported in the current literature.

The combination of amlodipine/valsartan 5/160 mg produces less peripheral oedema than amlodipine 10 mg in hypertensive patients not adequately controlled with amlodipine 5 mg.

AIMS: To demonstrate the benefit of the combination amlodipine/valsartan 5/160 mg over amlodipine 10 mg, in producing a lower incidence of peripheral oedema for a comparable mean sitting systolic blood pressure (MSSBP) reduction. METHODS: After a 4-week amlodipine 5 mg run-in phase, inadequately controlled hypertension patients (aged > or = 55 years, MSSBP > or = 130 and < or = 160 mmHg) were randomised to receive amlodipine/valsartan 5/160 mg or amlodipine 10 mg for 8 weeks, followed by amlodipine/valsartan 5/160 mg for 4 weeks for all patients. Primary variables were MSSBP change from baseline to week 8 and incidence of peripheral oedema reported as an AE. Resolution of peripheral oedema was assessed 4 weeks after switching patients from amlodipine 10 mg to amlodipine/ valsartan 5/160 mg. RESULTS: At week 8, MSSBP showed greater reduction with amlodipine/valsartan 5/160 mg than amlodipine 10 mg (least square mean: -8.01 vs.-5.95 mmHg, p < 0.001 for non-inferiority and p = 0.002 for superiority). Systolic control, overall BP control and systolic response rate at week 8 were significantly higher with combination than amlodipine 10 mg (34 vs. 26%; 57 vs. 50%; 36.57 vs. 27.77%, respectively). Incidence of peripheral oedema was significantly lower with the combination than amlodipine 10 mg (6.6 vs. 31.1%, p < 0.001). Peripheral oedema resolved in 56% patients who switched from amlodipine 10 mg to the combination, without the loss of effect on BP reduction. CONCLUSION: In non-responders to amlodipine 5 mg, treatment with amlodipine/valsartan 5/160 mg induced significantly less peripheral oedema than amlodipine 10 mg for similar BP reduction. Peripheral oedema resolved in > 50% patients switching from amlodipine 10 mg to the combination.

[Influence of inlay height on motion characteristics of lumbar segments in total disc replacement]. / Einfluss der Inlaygrösse einer lumbalen Bandscheibenprothese auf das Bewegungsverhalten.

AIM OF THE STUDY: Maintaining segmental motion is one of the most reported theoretical advantages of total disc replacement (TDR). Several inlay sizes are available for reconstruction of the physiological disc height. The influence of the implant height on the range of motion (ROM) was investigated in a biomechanical study. METHODS: A total of 10 human lumbar cadaver spines were subjected to biomechanical testing. Flexion/extension and side-bending moments were applied from 2.5-7.5 Nm on a spine load simulator allowing for all 6 degrees of freedom. Motion under different loads was monitored by the Zebris system in 3 dimensions. Initially intact specimens were tested in 3 load cycles. Then a total disc prothesis was implanted with an 8.5 mm inlay and the cycles were repeated. Finally in 5 cases a 1-mm larger inlay was inserted while in the remaining 5 cases the inlay was exchanged with a 2-mm larger implant. Neutral zone (NZ) and ROM were recorded under the different loads. RESULTS: The average motion for the various loads showed no significant difference when the intact motion segment was compared to the specimen containing the 8.5-mm inlay. After the larger inlay had been mounted the average reduction of the ROM in flexion/extension was 25% under the load of 7.5 Nm, 26% under a torque of 5.0 Nm and 30% when 2.5 Nm were applied. The NZ was reduced by 37%. For side-bending the ROM was reduced by 21% under a load of 7.5 Nm, by 26% under 5.0 Nm and by 35% under a torque of 2.5 Nm. The NZ was decreased by 27%. The reduction of the ROM was significant (p=0.0057). CONCLUSION: Segmental lumbar motion is maintained after TDR. The size of the inlay can significantly change the ROM in lumbar spine segments treated by TDR.

[Intraspinal echinococcosis within the lumbar spine of an 18-year-old male patient]. / Intraspinale Echinokokkose der Lendenwirbelsäule eines 18-jährigen männlichen Patienten.

Echinococcosis of human pathogenetic relevance is a very rare disease in Europe. The vertebral manifestation of the latter zoonosis constitutes one percent of all cases. Intraspinal echinococcosis appears worldwide just sporadically, whereas extradurally located cysts are identified more often than intradurally located ones. The diagnostic and specific therapeutic consequences of this very seldom entity are discussed based on a case report.

Plasma urate and risk of Parkinson's disease.

Oxidative stress contributes to dopaminergic neuron degeneration in Parkinson's disease. Urate, a potent antioxidant, could be neuroprotective. To determine whether higher plasma concentrations of urate predict a reduced risk of Parkinson's disease, the authors conducted a nested case-control study among participants in the Health Professionals Follow-up Study, a cohort comprising over 18,000 men who provided blood samples in 1993-1995. Eighty-four incident cases of Parkinson's disease were diagnosed through 2000, and each was randomly matched to two controls by year of birth, race, and time of blood collection. Rate ratios of Parkinson's disease according to quartile of uricemia were estimated by use of conditional logistic regression. The mean urate concentration was 5.7 mg/dl among cases and 6.1 mg/dl among controls (p = 0.01). After adjustment for age, smoking, and caffeine, the rate ratio of Parkinson's disease for the highest quartile of uricemia compared with the lowest was 0.43 (95% confidence interval: 0.18, 1.02; p(trend) = 0.017). This association was stronger in analyses excluding cases diagnosed within 4 years (median) from blood collection (rate ratio = 0.17, 95% confidence interval: 0.04, 0.69; p(trend) = 0.010). These results suggest that high plasma urate concentrations may decrease the risk of Parkinson's disease, and they raise the possibility that interventions to increase plasma urate may reduce the risk and delay the progression of Parkinson's disease.