A NEW METHOD OF SURGICAL TREATMENT OF LUMBAR SPINAL STENOSIS

As the treatment of lumbar or lumbosacral stenosis, laminectomy with the preservation of tissues supporting the spine and the embracement of the exposed dura mater with thin silicone rubber to prevent the occurrence of restenosis due to exuberant fibrous tissue formation at the operative site have been performed over a period of seven years. Before the prevention of restenosis with silicone rubber, we had to reoperate in cases which developed recurrent symptoms resulting from restenosis of the lumbosacral canal. This operation that we describe is technically feasible and with practical benefit can be done routinely for spinal decompression not only in the lumbosaral, but also in cervical spinal region without requiring an extensive laminectomy

INTRAOPERATIVE ANGIOGRAPHIC ASSESSMENT OF RECONSTRUCTED ARTERY AND USEFULNESS OF SAPHENOUS VEIN GRAFT BRIDGING IN EARLY THROMBOSIS OCCLUSION AFTER CAROTID ENDARTERECTOMY

Early postoperative thrombosis-occlusion of the internal carotid artery after carotid endarterectomy plays a major role in postoperative neurologic morbidity and mortality. To prevent this terrible complication, many surgeons are trying various prophylactic methods such as saphenous vein patch angioplasty, prolonged use of heparin, intraoperative Doppler ultrasound assessment, and so on. However, complete protection from postoperative thrombosis-occlusion is difficult. We have performed 47 carotid endarterectomies on 43 patients in the last three years. In 28 of these endarterectomies, primary closure for arteriotomy was performed, and in 19 cases, endarterectomies were reconstructed with saphenous vein patch angioplasty. An intraoperative angiographical assessment of the reconstructed segment was done in all endarterectomies after the reversing of heparin given during the carotid arterial surgical maneuver, and restenosis, or thrombosis-occlusion, was also checked. In three arteries, restenosis was demonstrated and repair was performed with vein graft angioplasty. Three of 28 arteries recontructed with primary closure and 1 of 19 arteries with vein patch angioplasty showed thrombosis-occlusion. Although vein patch angioplasty was done immediately for the primarily closured arteries, occlusion occurred again in two arteries. One artery with patch angioplasty also reoccluded. For these arteries, saphenous vein graft bridging between common carotid artery with an intact intima and internal carotid artery with an intact intima was performed. Postoperative angiogram showed good blood flow through the vein graft bridge. These results suggest that intraoperative angiography gives important imformation about the reconstructed arterial segment and that saphenous vein bridging is very useful in arteries with thrombosis-occlusion following carotid endarterectomy

Local Gene Delivery System by Bubble Liposomes and Ultrasound Exposure into Joint Synovium

Recently, we have developed novel polyethylene glycol modified liposomes (bubble liposomes; BL) entrapping an ultrasound (US) imaging gas, which can work as a gene delivery tool with US exposure. In this study, we investigated the usefulness of US-mediated gene transfer systems with BL into synoviocytes in vitro and joint synovium in vivo. Highly efficient gene transfer could be achieved in the cultured primary synoviocytes transfected with the combination of BL and US exposure, compared to treatment with plasmid DNA (pDNA) alone, pDNA plus BL, or pDNA plus US. When BL was injected into the knee joints of mice, and US exposure was applied transcutaneously to the injection site, highly efficient gene expression could be observed in the knee joint transfected with the combination of BL and US exposure, compared to treatment with pDNA alone, pDNA plus BL, or pDNA plus US. The localized and prolonged gene expression was also shown by an in vivo luciferase imaging system. Thus, this local gene delivery system into joint synovium using the combination of BL and US exposure may be an effective means for gene therapy in joint disorders

CLINICOPATHOLOGICAL STUDY OF CEREBRAL SUBCORTICAL CAVERNOUS ANGIOMA AS EPILEPTOGENIC FOCUS

The authors conducted a comparative histological study of two groups of patients with cerebral subcortical cavernous angioma. One group was composed of 5 asymptomatic cases detected accidentally. The other group was composed of 4 patients presenting as epilepsy. The results obtained may be summarized as follows ; 1) Hemosiderin deposit and gliosis were seen in all cases examined ; 2) Granulomatous change was a histological finding associated with epileptogenesis ; 3) The histological changes, starting with proliferation of collagen fibers and leading to hyaline degeneration, calcification, and then hemangioma calcificans, seem to represent a course of spontaneous healing, when viewed from epileptogenesis

Development of cosmic x-ray polarimeter

We present a performance study of a cosmic X-ray polarimeter which is based on the photoelectric effect in gas, and sensitive to a few to 30 keV range. In our polarimeter, the key device would be the 50 μm pitch Gas Electron Multiplier (GEM). We have evaluated the modulation factor using highly polarized X-ray, provided by a synchrotron accelerator. In the analysis, we selected events by the eccentricity of the charge cloud of the photoelectron track. As a result, we obtained the relationship between the selection criteria for the eccentricity and the modulation factors; for example, when we selected the events which have their eccentricity of > 0.95, the polarimeter exhibited with the modulation factor of 0.32. In addition, we estimated the Minimum Detectable Polarization degree (MDP) of Crab Nebula with our polarimeter and found 10 ksec observation is enough to detect the polarization, if we adopt suitable X-ray mirrors

Structural basis for recognition of cognate tRNA by tyrosyl-tRNA synthetase from three kingdoms

The specific aminoacylation of tRNA by tyrosyl-tRNA synthetases (TyrRSs) relies on the identity determinants in the cognate tRNATyrs. We have determined the crystal structure of Saccharomyces cerevisiae TyrRS (SceTyrRS) complexed with a Tyr-AMP analog and the native tRNATyr(GΨA). Structural information for TyrRS–tRNATyr complexes is now full-line for three kingdoms. Because the archaeal/eukaryotic TyrRSs–tRNATyrs pairs do not cross-react with their bacterial counterparts, the recognition modes of the identity determinants by the archaeal/eukaryotic TyrRSs were expected to be similar to each other but different from that by the bacterial TyrRSs. Interestingly, however, the tRNATyr recognition modes of SceTyrRS have both similarities and differences compared with those in the archaeal TyrRS: the recognition of the C1-G72 base pair by SceTyrRS is similar to that by the archaeal TyrRS, whereas the recognition of the A73 by SceTyrRS is different from that by the archaeal TyrRS but similar to that by the bacterial TyrRS. Thus, the lack of cross-reactivity between archaeal/eukaryotic and bacterial TyrRS-tRNATyr pairs most probably lies in the different sequence of the last base pair of the acceptor stem (C1-G72 vs G1-C72) of tRNATyr. On the other hand, the recognition mode of Tyr-AMP is conserved among the TyrRSs from the three kingdoms

Emergence of Dynamically-Disordered Phases During Fast Oxygen Deintercalation Reaction of Layered Perovskite

Determination of a reaction pathway is an important issue for the optimization of reactions. However, reactions in solid-state compounds have remained poorly understood because of their complexity and technical limitations. Here, using state-of-the-art high-speed time-resolved synchrotron X-ray techniques, the topochemical solid-gas reduction mechanisms in layered perovskite Sr3Fe2O7−δ (from δ ∼ 0.4 to δ = 1.0), which is promising for an environmental catalyst material is revealed. Pristine Sr3Fe2O7−δ shows a gradual single-phase structural evolution during reduction, indicating that the reaction continuously proceeds through thermodynamically stable phases. In contrast, a nonequilibrium dynamically-disordered phase emerges a few seconds before a first-order transition during the reduction of a Pd-loaded sample. This drastic change in the reaction pathway can be explained by a change in the rate-determining step. The synchrotron X-ray technique can be applied to various solid-gas reactions and provides an opportunity for gaining a better understanding and optimizing reactions in solid-state compounds