Probing quark-gluon interactions with transverse polarized scattering

We have extracted QCD matrix elements from our data on doubly polarized inelastic scattering of electrons on nuclei. We find the higher twist matrix element d˜2, which arises strictly from quark-gluon interactions, to be unambiguously nonzero. The data also reveal an isospin dependence of higher twist effects if we assume that the Burkhardt-Cottingham sum rule is valid. The fundamental Bjorken sum rule obtained from the a0 matrix element is satisfied at our low momentum transfer.

Size of the largest lymph node visualized on multi-detector-row computed tomography (MDCT) is useful in predicting metastatic lymph node status of gastric cancer

This study was designed to investigate whether the size of the largest lymph node (long-axis diameter [LAD] and short-axis diameter [SAD]) visualized using multi-detector-row computed tomography (MDCT) was useful for predicting the metastatic lymph node (MLN) status of gastric cancer. A retrospective analysis of 305 gastric cancer patients who underwent pre-operative MDCT was performed, followed by a prospective study in 61 gastric cancer patients to determine the diagnostic effectiveness of LAD and SAD. In the retrospective study, the accuracy of LAD and SAD for predicting the MLN status of gastric cancer was 51.1% and 45.9%, respectively. In the prospective study, the accuracy of LAD and SAD measurement and the traditional MDCT method of counting MLNs was 52.5%, 49.2% and 57.4%, respectively; the differences were not significant. In conclusion, the size of the largest lymph node in terms of LAD and SAD visualized on MDCT was useful for predicting the MLN status of gastric cancer, with accuracy comparable to the traditional MDCT method of counting the total number of MLNs detected.

A pseudoinverse deformation vector field generator and its applications

PURPOSE

To present, implement, and test a self-consistent pseudoinverse displacement vector field (PIDVF) generator, which preserves the location of information mapped back-and-forth between image sets.

METHODS

The algorithm is an iterative scheme based on nearest neighbor interpolation and a subsequent iterative search. Performance of the algorithm is benchmarked using a lung 4DCT data set with six CT images from different breathing phases and eight CT images for a single prostrate patient acquired on different days. A diffeomorphic deformable image registration is used to validate our PIDVFs. Additionally, the PIDVF is used to measure the self-consistency of two nondiffeomorphic algorithms which do not use a self-consistency constraint: The ITK Demons algorithm for the lung patient images and an in-house B-Spline algorithm for the prostate patient images. Both Demons and B-Spline have been QAed through contour comparison. Self-consistency is determined by using a DIR to generate a displacement vector field (DVF) between reference image R and study image S (DVF(R-S)). The same DIR is used to generate DVF(S-R). Additionally, our PIDVF generator is used to create PIDVF(S-R). Back-and-forth mapping of a set of points (used as surrogates of contours) using DVF(R-S) and DVF(S-R) is compared to back-and-forth mapping performed with DVF(R-S) and PIDVF(S-R). The Euclidean distances between the original unmapped points and the mapped points are used as a self-consistency measure.

RESULTS

Test results demonstrate that the consistency error observed in back-and-forth mappings can be reduced two to nine times in point mapping and 1.5 to three times in dose mapping when the PIDVF is used in place of the B-Spline algorithm. These self-consistency improvements are not affected by the exchanging of R and S. It is also demonstrated that differences between DVF(S-R) and PIDVF(S-R) can be used as a criteria to check the quality of the DVF.

CONCLUSIONS

Use of DVF and its PIDVF will improve the self-consistency of points, contour, and dose mappings in image guided adaptive therapy.

Antibiotic prophylaxis after total joint replacements

OBJECTIVES

To review the latest evidence on antibiotic prophylaxis for patients with total joint replacements to prevent prosthesis infections.

DATA SOURCES

Literature search of Medline and PubMed until June 2009.

STUDY SELECTION

Studies of patients with total joint replacements from around the world, studies concerning antibiotic prophylaxis, as well as chemoprophylaxis guidelines from orthopaedic associations were searched.

DATA EXTRACTION

Literature review, original articles, case reports, best practice guidelines.

DATA SYNTHESIS

With the rising incidence of patients with total joint replacements, subsequent deep infection of the implants is a rare but dreaded complication which has immense physiological, psychological, financial, and social implications. Guidelines from urologists, gastroenterologists, and dental surgeons attempt to identify high-risk patients who may be more susceptible to prosthetic joint infections. These patients are provided with prophylactic antibiotics before any invasive procedure that may cause bacterial seeding to prosthetic joints. Most orthopaedic associations around the world adopt a similar policy to provide prophylaxis to cover any anticipated chance of bacteraemia. The American Association of Orthopaedic Surgeons adopts the most cautious approach in which all patients with total joint replacements who undergo any procedure that breaches a mucosal surface receive prophylactic antibiotics.

CONCLUSION

The guidelines from the American Association of Orthopaedic Surgeons seem to have an all-encompassing policy when it comes to providing prophylactic antibiotics. Nonetheless, physicians must still exercise their judgement and customise the treatment to each patient. The benefits of prophylactic antibiotics must be balanced against the risks of drug side-effects and the emergence of antibiotic resistance.

Factors associated with bed and room sharing in Chinese school-aged children

BACKGROUND AND OBJECTIVES

Co-sleeping (bed or room sharing) has potential implications for children's development. Previous studies showed that co-sleeping was more prevalent in non-Western countries than in Western countries, which demonstrated that co-sleeping was marked with ethnic and socio-cultural background characteristics. The purpose of this study was to survey the prevalence of bed and room sharing and to examine related factors among school-aged children in an Asian country - China.

METHODS

A cross-sectional questionnaire survey was conducted in 10 districts of Shanghai, China from November to December 2005. A total of 4108 elementary school children, 49.2% boys and 50.8% girls with a mean age of 8.79 years, participated. Parent-administered questionnaires were used to collect information about children's sleeping arrangements and socio-demographic characteristics.

RESULTS

The prevalence of routine bed sharing, room sharing and sleeping alone in Chinese school-aged children was 21.0%, 19.1% and 47.7%, respectively. Bed and room sharing didn't show significant gender difference but gradually decreased with increasing age. Multivariate logistic regression identified those factors associated with bed and room sharing: younger age, large family, children without their own bedroom and parents' approval of a co-sleeping arrangement.

CONCLUSION

Co-sleeping arrangement was a common practice in Chinese school-aged children. Associated factors were characterized by intrinsic socio-cultural values and socio-economic status in China.

Inter- and intra-observer errors in identifying the transepicondylar axis and Whiteside's line

PURPOSE

To assess inter- and intra-observer errors in identifying the transepicondylar axis and Whiteside's line in a cadaveric model mimicking total knee arthroplasty.

METHODS

Four cadaveric knees with intact soft tissues were used. The knees were exposed anteriorly using the Insall approach, with the patella everted laterally. Three observers (2 surgeons and one trainee) took turns to identify the anatomic landmarks of the transepicondylar axis and Whiteside's line. Each observer repeated the process 20 times. Each identification was photographed and referenced with the true values obtained from the knees after they were stripped of all soft tissue. Inter- and intra-observer errors in the anatomic landmarks were compared.

RESULTS

Inter-observer error was significant with both the transepicondylar axis and Whiteside's line (p<0.001, one-way ANOVA). The intra-observer variation was greater for Whiteside's line than the transepicondylar axis (standard deviation, 4.2 vs 2.5 degrees). The maximum potential errors in the transepicondylar axis and Whiteside's line were 13 degrees and 24 degrees, respectively.

CONCLUSION

The accuracy of rotational alignment of the transepicondylar axis and Whiteside's line were operator-dependent, and their intra-operative reproducibility was low.

Urinary level of nickel and acute leukaemia in Chinese children

The 8-hydroxy-2′-deoxyguanosine (8-OHdG), an oxidized nucleoside of DNA, not only is a widely used biomarker for the measurement of endogenous oxidative DNA damage but might also be a risk factor for many diseases including cancer. Metal exposure may play an important role in oxidative DNA damage among children. However, few studies on urinary 8-OHdG and metals have been conducted in children with acute leukemia. In the present study, urinary Ni and 8-OHdG were examined in 116 children with acute leukaemia (94 acute lymphoid leukaemia [ALL] and 22 acute myeloid leukaemia [AML]) and 51 healthy child controls. Our result showed that urinary Ni in acute leukaemia patients (ALL: 68.40 ± 133.98, AML: 41.48 ± 76.31 ng/mg creatinine) was significantly higher than that in controls (62.47 ± 124.90 vs 17.63 ± 46.17 ng/mg creatinine, P < 0.05). Similarly, the pretherapy level of urinary 8-OHdG in patients (ALL: 11.83 ± 16.23, AML: 12.36 ± 11.36 ng/mg creatinine) was significantly elevated compared with controls (11.92 ± 15.42 vs 4.03 ± 4.70 ng/mg creatinine, P < 0.05). Moreover, urinary 8-OHdG and urinary Ni showed a weak but significant association with increased risk of childhood leukaemia. The present study suggests that Ni may be an etiologic factor for childhood acute leukaemia by oxidative DNA damage.

Analysis and location of a rice BAC clone containing telomeric DNA sequences

BAC2, a rice BAC clone containing (TTTAGGG)(n) homologous sequences, was analyzed by Southern hybridization and DNA sequencing of its subclones. It was disclosed that there were many tandem repeated satellite DNA sequences, called TA352, as well as simple tandem repeats consisting of TTTAGGG or its variant within the BAC2 insert. A 0. 8 kb (TTTAGGG)(n)-containing fragment in BAC2 was mapped in the telomere regions of at least 5 pairs of rice chromosomes by using fluorescencein situ hybridization (FISH). By RFLP analysis of low copy sequences the BAC2 clone was localized in one terminal region of chromosome 6. All the results strongly suggest that the telomeric DNA sequences of rice are TTTAGGG or its variant, and the linked satellite DNA TA352 sequences belong to telomere-associated sequences.

Bilateral knee lipoma arborescens: a case report

A 45-year-old Chinese man presented with recurrent bilateral knee swelling and pain. He was initially diagnosed with gouty arthritis, but later found to have lipoma arborescens. Magnetic resonance imaging demonstrated frond-like proliferations of fatty synovium. Arthroscopic synovectomy was performed. Histological examination of the specimen revealed villiform fatty tissue covered by slightly thickened synovium characteristic of lipoma arborescens. Magnetic resonance imaging is useful in differentiating lipoma arborescens from other intra-articular lesions in patients with recurrent knee pain and swelling.