Double Spine Research Articles

Traumatic Death due to Simultaneous Double Spine Fractures in Patient with Ankylosing Spondylitis.

The aim of this study is to report the rare occurrence of simultaneous double spine fractures in a patient with progressive ankylosing spondylitis (AS). An 82-year-old male with established AS had low-energy falls. He had sustained simultaneous double spine fractures and died. Plain radiographs of the cervical spine were unremarkable in detecting a cervical spine fracture in a patient with AS and a spinal cord injury following a fall. CT scan showed a displaced fracture at the C6/C7 with American Spinal Injury Association-A spinal cord injury and displaced fracture at L1. The cause of death was determined to be upper spinal cord injury caused by cervical spinal fracture and dislocation that were facilitated by spinal rigidity from AS. This case report illustrates the importance of obtaining a detailed medical history and thorough imaging study when investigating deaths, including nonfatal conditions, such as AS. Furthermore, it shows the value of entire spine CT scan in the evaluation of the mechanism, further spine fractures, and manner of death. Despite the occurrence of spine fracture in AS patients, simultaneous double or multiple spine fractures are extremely rare and can be missed. Care should be taken for the further spine fracture in the entire spine in patient with AS.

Circumferential fusion using a custom-made screw in the management of high-grade spondylolisthesis.

Management of high-grade spondylolisthesis is challenging and to date no therapeutic consensus is available. Various surgical procedures have been described using unique or double approach. The aim of the study is to describe an original technique using a posterior-only approach to achieve a circumferential lumbosacral fusion with a custom-made screw. In our experience, eight patients (mean age 15years old) were treated for grade III or IV slipping without instrumental reduction. Surgical technique included a laminectomy from L5 to S2, then after mobilization of neural elements a guide wire was inserted from the posterior side of S2 to the antero-superior corner of L5. A specific drill was used and the 10-mm screw was then inserted under fluoroscopic guidance. Further steps included a discectomy, lumbosacral interbody graft and posterolateral graft to obtain a circumferential fusion. Clinical and radiological evaluations were obtained. On the whole series, solid fusion was achieved after 6months on average. Sagittal realignment was observed with a regression of pelvic retroversion and hip flessum, a lumbarization of the lumbar lordosis and an improvement of the thoracic kyphosis. For one patient, a postoperative S1 deficit was observed. This technique provides satisfactory results in the management of high-grade spondylolisthesis. This concept is based on a double spine instability considering viscoelastic properties of the disc and postoperative sagittal reciprocal changes as prerequisite. This posterior-only approach represents a valuable alternative to other procedures.

Mediation of the A/B-DNA helix transition by G-tracts in the crystal structure of duplex CATGGGCCCATG.

The crystal structure of the DNA dodecamer duplex CATGGGCCCATG lies on a structural continuum along the transition between A- and B-DNA. The dodecamer possesses the normal vector plot and inclination values typical of B-DNA, but has the crystal packing, helical twist, groove width, sugar pucker, slide and x-displacement values typical of A-DNA. The structure shows highly ordered water structures, such as a double spine of water molecules against each side of the major groove, stabilizing the GC base pairs in an A-like conformation. The different hydration of GC and AT base pairs provides a physical basis for solvent-dependent facilitation of the A<-->B helix transition by GC base pairs. Crystal structures of CATGGGCCCATG and other A/B-DNA intermediates support a 'slide first, roll later' mechanism for the B-->A helix transition. In the distribution of helical parameters in protein-DNA crystal structures, GpG base steps show A-like properties, reflecting their innate predisposition for the A conformation.

Segregation for Double Spine Trait in Hybrids of Microcitrus inodora

Several Microcitrus species are valuable as parents in breeding citrus rootstocks and scions because of useful characteristics, such as monoembryony, very short juvenility, short fruit maturation time, and resistance to Phytophthora and nematodes. The large-leaf Australian wild lime, Microcitrus inodora (F. M. Bail.) Swing., also possesses a trait that is generally undesireable in new hybrids, double axillary spines. Most F1 hybrids between M. inodora and single-spine Microcitrus and Citrus species were observed to possess the double spine trait. In crosses of M. australasica (F. Muell.) Swing. × M. inodora, M. papuana H. F. Winters × M. inodora, and M. warburgiana (F. M. Bail.) Tan. × M. inodora, double spines were present in 80%, 81%, and 87% of the progeny, respectively. In hybrids of Citrus species with M. inodora, percentage of double spines varied from 43% in progeny from M. inodora × Citrus aurantium L., to 100% in progeny from M. inodora × Citrus ichangensis Swing. When double-spined hybrids of M. inodora were used as parents in crosses with other single-spined Citrus species or hybrids, progenies varied from 0 to 86% with double spines. The patterns of inheritance suggest that the double spine trait is controlled by an allele of a nuclear gene that is dominant and homozygous in M. inodora, but that one or more other independently segregating alleles are necessary for expression of the double spine trait in advanced generation hybrids.

Crystal structure of the B-DNA hexamer d(CTCGAG): model for an A-to-B transition

The crystal structure of the B-DNA hexamer d(CTCGAG) has been solved at 1.9 A resolution by iterative single isomorphous replacement, using the brominated derivative d(CG5BrCGAG), and refined to an R-factor of 18.6% for 120 nonhydrogen nucleic acid atoms and 32 water molecules. Although the central four base pairs form a typical B-form helix, several parameters suggest a transition to an A-like conformation at the termini. Based on this observation, a B-to-A transition was modeled, maintaining efficient base stacking across the junction. The wide minor groove (approximately 6.9 A) is reminiscent of that in the side-by-side double drug-DNA complexes and hosts a double spine of hydration. The global helix axes of the pseudo-continuous helices are at an acute angle of 60 degrees. The pseudocontinuous stacking is reinforced by the minor groove water structure extending between the two duplexes. The crossover point of two pairs of stacked duplexes is at the stacking junction, unlike that observed in the B-DNA decamers and dodecamers. This arrangement may have implications for the structure of a four-way DNA junction. The duplexes are arranged around a large (approximately 20 A diameter) channel centered on a 6(2) screw axis.

Surface structure of germinating Uromyces dianthi urediospores as observed by scanning electron microscope

Germ pore regions could not be located on the surface of Uromyces dianthi urediospores before germination. Germ tube emergence did not split the spore wall. Double spine features were observed on the spore surface.