The attachments of the anteromedial and posterolateral fibre bundles of the anterior cruciate ligament

The tibial attachments of the individual anteromedial (AM) and posterolateral (PL) fibre bundles and the entire attachment of the anterior cruciate ligament are described, relating them to consistent bony landmarks; 55 fresh-frozen specimens were measured. The fibre bundles were separated and excised at their attachments and their peripheries marked with a pen. High-resolution scaled digital photographs were taken of each dissected specimen and transferred onto a computer for analysis. A wide variation was found when using the posterior tibial axis, the anterior tibial surface and the medial tibial spine as reference points. The most consistent measurements used the tibial interspinous “over-the-back” ridge as a datum. The attachments of the PL and AM bundles were centred 10 ± 1 mm (mean ± SD) and 17 ± 2 mm anterior to the over-the-back ridge. They were 4 ± 1 and 5 ± 1 mm, respectively, lateral to the medial tibial spine border. The positions of 6 mm circles in the posterior-medial limits of the fibre bundles (representing tunnels in a double-tunnel reconstruction) were measured. The overall dimensions of the tibial plateaux correlated significantly with many measurements. The results from this study could be used to guide ACL reconstruction techniques.     

Hemorrhagic and nonhemorrhagic brain lesions: evaluation with 0.35-T fast MR imaging

Two fast magnetic resonance (MR) imaging techniques, advanced Fourier and partial-flip imaging, were used at 0.35 T to examine 21 patients with suspected intracranial lesions; the results were quantitatively compared with a conventional spin-echo study. Both of the fast MR techniques yielded a fourfold reduction in imaging time per section. The advanced Fourier sequence showed contrast that was identical to the conventional spin-echo study with signal-to-noise ratios of 58% and 57% for the first and second echoes, respectively. The partial-flip sequence showed a contrast of 109% and 57% for lesions versus substantia alba, and 107% and 78% for substantia grisea versus substantia alba relative to the first and second echoes of the conventional spin-echo study. The partial-flip sequence was particularly sensitive to magnetic susceptibility; this produced artifacts that may undermine the usefulness of partial flip for routine screening in certain parts of the brain. However, this susceptibility significantly improved the detection of intracranial hemorrhage when compared with the spin-echo sequence, particularly when combined with phase mapping of the partial-flip study.     

The strength of surgical repairs of the rotator cuff. A biomechanical study on cadavers.

Using 26 cadaver shoulders, we produced a standard defect in the supraspinatus tendon and performed one of three types of repair. Their strength was found by testing in tension the force required to produce a gap of 3 mm, then 6 mm, and finally total disruption of the repair. The use of a polyethylene patch to spread the forces over the lateral bone surface and of extra sutures to grasp the tendon end raised by 2.6 times the load at which a 3 mm gap in the repair occurred and by 1.7 times the load to failure.     

Decrement of the skin conductance response to repeated volitional inspiration.

OBJECTIVE: To examine response decrement of the recently reported inspiratory skin conductance response (SCR) [Lim CL, Seto-Poon M, Clouston PD, Morris JG. Sudomotor nerve conduction velocity and central processing time of the skin conductance response. Clin Neurophysiol 2003;114:2172-80]. METHODS: Twelve healthy adult volunteers performed 3 tasks (A) a control task of maintaining tidal breathing and then two randomized tasks, (B) a deep inspiration to a target oral pressure and (C) tapping with a finger. Each task was performed 30 times on cue every 20s in 3 runs with 5 min of rest between runs. The SCR, oral pressure, airflow, inspired volume and cue signal were recorded continuously and analysed offline. SCR amplitude was logarithmically transformed and then statistically analysed, using a linear mixed effects model, as a function of run number, trial number and absolute error between target and actual oral pressures. RESULTS: Inspiratory efforts elicited exponentially decreasing SCR amplitude with increasing trial number during each run (P < 0.0001). After adjusting for trial number, the mean SCR amplitude of the second and the third run were, respectively, 24.2 (95% CI (0.175, 0.336), P < 0.001) and 14.4% (95% CI (0.104, 0.200), P < 0.001) of the first run amplitude. CONCLUSIONS: Volitional deep inspiration reliably activates an SCR that exhibits response decrement with repetition, which may be habituation. SIGNIFICANCE: The volitional inspiratory SCR may assist in the assessment of sympathetic autonomic status in patients with peripheral afferent neuropathy.     

Rapid prototyping techniques for anatomical modelling in medicine.

The rapid advances in computer technology, often driven by the demands of industry, have created new possibilities in surgery which previous generations of surgeons could only have imagined. Improved imaging with computerised tomography (CT) has been followed by magnetic resonance imaging (MRI) and, more recently, it has become possible to reformat the data as three-dimensional images. Computer technology has new moved forward with the advent of rapid prototyping techniques (RPT) which allow both the production of models of the hard tissues and custom-made prostheses from computerised scanning data. In this article we review the development and current technologies available in RPT and the applications of this advance in surgery and illustrate this with two case reports.     

Missense mutation in a von Willebrand factor type A domain of the alpha 3(VI) collagen gene (COL6A3) in a family with Bethlem myopathy

The Bethlem myopathy is a rare autosomal dominant proximal myopathy characterized by early childhood onset and joint contractures. Evidence for linkage and genetic heterogeneity has been established, with the majority of families linked to 21q22.3 and one large family linked to 2q37, implicating the three type VI collagen subunit genes, COL6A1 (chromosome 21), COL6A2 (chromosome 21) and COL6A3 (chromosome 2) as candidate genes. Mutations of the invariant glycine residues in the triple-helical domain-coding region of COL6A1 and COL6A2 have been reported previously in the chromosome 21-linked families. We report here the identification of a G-->A mutation in the N-terminal globular domain-coding region of COL6A3 in a large American pedigree (19 affected, 12 unaffected), leading to the substitution of glycine by glutamic acid in the N2 motif, which is homologous to the type A domains of the von Willebrand factor. This mutation segregated to all affected family members, to no unaffected family members, and was not identified in 338 unrelated Caucasian control chromosomes. Thus mutations in either the triple-helical domain or the globular domain of type VI collagen appear to cause Bethlem myopathy.      

Beckman EL-ISE电解质分析仪准确性及故障的分析判断

0 引言为了克服离子选择电极（ISE）法的微量电位信号极易受环境温度变化及电子噪声的干扰问题,该仪器采用了参考电极,把参考电极与其测定电极装在同一测量室内,保持其相同的物理环境,使干扰源对所有电极的影响相同. 以内参液作为参考电极的测量对象,测得一个参考电极电位值,再测样品的电极电位值,二者相抵就消除了所叠加的干扰信号.