GW170817: Observation of Gravitational Waves from a Binary Neutron Star Inspiral

On August 17, 2017 at 12∶41:04 UTC the Advanced LIGO and Advanced Virgo gravitational-wave detectors made their first observation of a binary neutron star inspiral. The signal, GW170817, was detected with a combined signal-to-noise ratio of 32.4 and a false-alarm-rate estimate of less than one per 8.0×10^{4}  years. We infer the component masses of the binary to be between 0.86 and 2.26  M_{⊙}, in agreement with masses of known neutron stars. Restricting the component spins to the range inferred in binary neutron stars, we find the component masses to be in the range 1.17-1.60  M_{⊙}, with the total mass of the system 2.74_{-0.01}^{+0.04}M_{⊙}. The source was localized within a sky region of 28  deg^{2} (90% probability) and had a luminosity distance of 40_{-14}^{+8}  Mpc, the closest and most precisely localized gravitational-wave signal yet. The association with the γ-ray burst GRB 170817A, detected by Fermi-GBM 1.7 s after the coalescence, corroborates the hypothesis of a neutron star merger and provides the first direct evidence of a link between these mergers and short γ-ray bursts. Subsequent identification of transient counterparts across the electromagnetic spectrum in the same location further supports the interpretation of this event as a neutron star merger. This unprecedented joint gravitational and electromagnetic observation provides insight into astrophysics, dense matter, gravitation, and cosmology.

Conversion of Bcl-2 to a Bax-like death effector by caspases

Caspases are a family of cysteine proteases implicated in the biochemical and morphological changes that occur during apoptosis (programmed cell death). The loop domain of Bcl-2 is cleaved at Asp34 by caspase-3 (CPP32) in vitro, in cells overexpressing caspase-3, and after induction of apoptosis by Fas ligation and interleukin-3 withdrawal. The carboxyl-terminal Bcl-2 cleavage product triggered cell death and accelerated Sindbis virus-induced apoptosis, which was dependent on the BH3 homology and transmembrane domains of Bcl-2. Inhibitor studies indicated that cleavage of Bcl-2 may further activate downstream caspases and contribute to amplification of the caspase cascade. Cleavage-resistant mutants of Bcl-2 had increased protection from interleukin-3 withdrawal and Sindbis virus-induced apoptosis. Thus, cleavage of Bcl-2 by caspases may ensure the inevitability of cell death.

Restenosis after successful percutaneous transluminal coronary angioplasty: serial angiographic follow-up of 229 patients

To further understand the temporal mode and mechanisms of coronary restenosis, 229 patients were studied by prospective angiographic follow-up on day 1 and at 1, 3 and 6 months and 1 year after successful percutaneous transluminal coronary angioplasty. Quantitative measurement of coronary stenosis was achieved by cinevideodensitometric analysis. Actuarial restenosis rate was 12.7% at 1 month, 43.0% at 3 months, 49.4% at 6 months and 52.5% at 1 year. In 219 patients followed up for greater than or equal to 3 months, mean stenosis diameter was 1.91 +/- 0.53 mm immediately after coronary angioplasty, 1.72 +/- 0.52 mm on day 1, 1.86 +/- 0.58 mm at 1 month and 1.43 +/- 0.67 mm at 3 months. In 149 patients followed up for greater than or equal to 6 months, mean stenosis diameter was 1.66 +/- 0.58 mm at 3 months and 1.66 +/- 0.62 mm at 6 months. In 73 patients followed up for 1 year, mean stenosis diameter was 1.65 +/- 0.56 mm at 6 months and 1.66 +/- 0.57 mm at 1 year. Thus, stenosis diameter decreased markedly between 1 month and 3 months after coronary angioplasty and reached a plateau thereafter. In conclusion, restenosis is most prevalent between 1 and 3 months and rarely occurs beyond 3 months after coronary angioplasty.

A combined assay of cell viability and in vitro cytotoxicity with a highly water-soluble tetrazolium salt, neutral red and crystal violet

Cell viability and in vitro cytotoxicity assay methods were developed using a combination of dyes, 4-[3-(4-iodophenyl)-2-(4-nitrophenyl)-2H-5-tetrazolio]-1,3-benzene disulfonate (WST-1), neutral red (NR) and crystal violet (CV), with HeLa cells as a bioindicatior. As WST-1 produces a highly water soluble and non-cytotoxic formazan dye, ti allows each assay to be carried out in one culture dish. The combined cell viability assay using WST-1, NR and CV gave an absorbance that correlated linearly with the number of cells over the range 1000 to 50,000 cells/well. The combined assay was applied to the evaluation of IC50 values for sodium dodecyl sulfate as a model toxicant, which yielded similar values to those obtained with each assay independently.

Modulation of cell death by Bcl-XL through caspase interaction

The caspases are cysteine proteases that have been implicated in the execution of programmed cell death in organisms ranging from nematodes to humans. Many members of the Bcl-2 family, including Bcl-XL, are potent inhibitors of programmed cell death and inhibit activation of caspases in cells. Here, we report a direct interaction between caspases and Bcl-XL. The loop domain of Bcl-XL is cleaved by caspases in vitro and in cells induced to undergo apoptotic death after Sindbis virus infection or interleukin 3 withdrawal. Mutation of the caspase cleavage site in Bcl-XL in conjunction with a mutation in the BH1 homology domain impairs the death-inhibitory activity of Bcl-XL, suggesting that interaction of Bcl-XL with caspases may be an important mechanism of inhibiting cell death. However, once Bcl-XL is cleaved, the C-terminal fragment of Bcl-XL potently induces apoptosis. Taken together, these findings indicate that the recognition/cleavage site of Bcl-XL may facilitate protection against cell death by acting at the level of caspase activation and that cleavage of Bcl-XL during the execution phase of cell death converts Bcl-XL from a protective to a lethal protein.

Efficient promoter cassettes for enhanced expression of foreign genes in dicotyledonous and monocotyledonous plants

A series of chimeric promoters for higher-level expression of foreign genes in plants was constructed as fusions of a gene for beta-glucuronidase (GUS) with the terminator of a gene for nopaline synthase (nos) or of the cauliflower mosaic virus (CaMV) 35S transcript, and the strength of these promoters was assayed in transient and stable expression systems in tobacco and rice. As parts of these promoters, the CaMV 35S core promoter, three different 5'-upstream sequences of the 35S promoter, the first intron of a gene for phaseolin, and a 5'-untranslated sequence (omega sequence) of tobacco mosaic virus were used in various combinations. In tobacco and rice protoplasts, all three fragments of the 35S promoter (-419 to -90, -390 to -90 and -290 to -90, relative to the site of initiation of transcription), the intron, and the omega sequence effectively enhanced GUS activity. Some chimeric promoters allowed levels of GUS activity that were 20- to 70-fold higher than those obtained with the 35S promoter in pBI221. In tobacco protoplasts, the two longer fragments of the 35S promoter were more effective than the shortest fragment. In rice cells, by contrast, the shortest fragment was as effective as the two longer ones. The terminator of the 35S transcript was more effective than that of the nos gene for gene expression. In transgenic tobacco plants, a representative powerful promoter, as compared to the 35S promoter, allowed 10- and 50-fold higher levels of expression on average and at most, respectively, with no clear qualitative differences in tissue- and organ-specific patterns of expression. When the representative promoter was introduced into tobacco with a gene for luciferase, the autofluorescence of detached leaves after a supply of luciferin to petioles was great and was easily detectable by the naked eye in a dark room.

Electric-field-induced superconductivity in an insulator

Electric field control of charge carrier density has long been a key technology to tune the physical properties of condensed matter, exploring the modern semiconductor industry. One of the big challenges is to increase the maximum attainable carrier density so that we can induce superconductivity in field-effect-transistor geometry. However, such experiments have so far been limited to modulation of the critical temperature in originally conducting samples because of dielectric breakdown. Here we report electric-field-induced superconductivity in an insulator by using an electric-double-layer gating in an organic electrolyte. Sheet carrier density was enhanced from zero to 10(14) cm(-2) by applying a gate voltage of up to 3.5 V to a pristine SrTiO(3) single-crystal channel. A two-dimensional superconducting state emerged below a critical temperature of 0.4 K, comparable to the maximum value for chemically doped bulk crystals, indicating this method as promising for searching for unprecedented superconducting states.

Effects of chitin and its derivatives on the proliferation and cytokine production of fibroblasts in vitro

The effects of chitin and its derivatives on the proliferation of fibroblasts and on the production of cytokines were examined in vitro. Chitin and its derivatives showed almost no acceleratory effect on the proliferation of cultured fibroblasts. On the contrary, high-concentration 500 micrograms ml-1) D-glucosamine cultures supplemented with or without a 10% fetal calf serum (FCS) supplementation showed a significant (P < 0.05) reduction in the rate of proliferation of L929 fibroblast cells relative to control. High-concentration chitosan cultures supplemented with 10% FCS showed a significant (P < 0.05) reduction in the rate of L929 fibroblast proliferation. However, the inhibition of cell proliferation by high concentrations of chitosan did not show in cultures without FCS. Interleukin-8 (IL-8) was induced in the supernatants of rat primary cultured dermal fibroblasts stimulated with chitin and its derivatives. Chitin and its derivatives did not stimulate the production of IL-6 by mouse dermal primary cultured fibroblasts. IL-1 alpha, IL-1 beta and tumour necrosis factor-alpha were not detected in the fibroblast supernatants. These observations support the notion that cell proliferation is accelerated indirectly by chitin and its derivatives when these materials are used in vivo. In vivo findings of a angiogenesis and migration of neutrophils may be due to persistent release of IL-8 from fibroblasts.

GW170104: Observation of a 50-Solar-Mass Binary Black Hole Coalescence at Redshift 0.2

We describe the observation of GW170104, a gravitational-wave signal produced by the coalescence of a pair of stellar-mass black holes. The signal was measured on January 4, 2017 at 10∶11:58.6 UTC by the twin advanced detectors of the Laser Interferometer Gravitational-Wave Observatory during their second observing run, with a network signal-to-noise ratio of 13 and a false alarm rate less than 1 in 70 000 years. The inferred component black hole masses are 31.2_{-6.0}^{+8.4}M_{⊙} and 19.4_{-5.9}^{+5.3}M_{⊙} (at the 90% credible level). The black hole spins are best constrained through measurement of the effective inspiral spin parameter, a mass-weighted combination of the spin components perpendicular to the orbital plane, χ_{eff}=-0.12_{-0.30}^{+0.21}. This result implies that spin configurations with both component spins positively aligned with the orbital angular momentum are disfavored. The source luminosity distance is 880_{-390}^{+450}  Mpc corresponding to a redshift of z=0.18_{-0.07}^{+0.08}. We constrain the magnitude of modifications to the gravitational-wave dispersion relation and perform null tests of general relativity. Assuming that gravitons are dispersed in vacuum like massive particles, we bound the graviton mass to m_{g}≤7.7×10^{-23}  eV/c^{2}. In all cases, we find that GW170104 is consistent with general relativity.

The effects of prostaglandin E2 in growing rats: increased metaphyseal hard tissue and cortico-endosteal bone formation

To assess the efficacy of PGE2 in inducing in vivo bone formation, graded doses of prostaglandins E2 were administered to 255 g rats. Histomorphometric analyses of selected sequential fluorescent-labeled bones of rats treated with 0, 0.3, 1.0, 3, or 6 mg PGE2/kg/d for 21 days showed that the doses PGE2 depressed longitudinal bone growth, increased growth cartilage thickness slightly, decreased degenerative cartilage cell size and cartilage cell production slightly, and increased proximal tibial metaphyseal hard-tissue mass markedly. Periosteal bone formation was depressed at the higher doses, and an early, slight depression in endosteal bone formation was also observed, along with a striking late increase in endosteal bone formation and in the formation of trabecular bone in the marrow cavity of the tibial shaft. The characteristics and magnitude of these responses were quite similar to those observed in our previous study of the effects of PGE2 on weanling rats except for the delayed increase in cortico-endosteal bone formation.

GW170817: Measurements of Neutron Star Radii and Equation of State

On 17 August 2017, the LIGO and Virgo observatories made the first direct detection of gravitational waves from the coalescence of a neutron star binary system. The detection of this gravitational-wave signal, GW170817, offers a novel opportunity to directly probe the properties of matter at the extreme conditions found in the interior of these stars. The initial, minimal-assumption analysis of the LIGO and Virgo data placed constraints on the tidal effects of the coalescing bodies, which were then translated to constraints on neutron star radii. Here, we expand upon previous analyses by working under the hypothesis that both bodies were neutron stars that are described by the same equation of state and have spins within the range observed in Galactic binary neutron stars. Our analysis employs two methods: the use of equation-of-state-insensitive relations between various macroscopic properties of the neutron stars and the use of an efficient parametrization of the defining function p(ρ) of the equation of state itself. From the LIGO and Virgo data alone and the first method, we measure the two neutron star radii as R_{1}=10.8_{-1.7}^{+2.0}  km for the heavier star and R_{2}=10.7_{-1.5}^{+2.1}  km for the lighter star at the 90% credible level. If we additionally require that the equation of state supports neutron stars with masses larger than 1.97  M_{⊙} as required from electromagnetic observations and employ the equation-of-state parametrization, we further constrain R_{1}=11.9_{-1.4}^{+1.4}  km and R_{2}=11.9_{-1.4}^{+1.4}  km at the 90% credible level. Finally, we obtain constraints on p(ρ) at supranuclear densities, with pressure at twice nuclear saturation density measured at 3.5_{-1.7}^{+2.7}×10^{34}  dyn cm^{-2} at the 90% level.

Observation of a narrow charmoniumlike state in exclusive B+/--->K+/-pi+pi-J/psi decays

We report the observation of a narrow charmoniumlike state produced in the exclusive decay process B+/--->K+/-pi(+)pi(-)J/psi. This state, which decays into pi(+)pi(-)J/psi, has a mass of 3872.0+/-0.6(stat)+/-0.5(syst) MeV, a value that is very near the M(D0)+M(D(*0)) mass threshold. The results are based on an analysis of 152M B-Bmacr; events collected at the Upsilon(4S) resonance in the Belle detector at the KEKB collider. The signal has a statistical significance that is in excess of 10sigma.

Surgical strategy for carcinoma of the pancreas head area based on clinicopathologic analysis of nodal involvement and plexus invasion

BACKGROUND

The pattern of tumor spread, vis-à-vis nodal involvement and invasion of the extrapancreatic plexus (Plx), has not been thoroughly described for carcinoma of the pancreatic head area.

METHODS

From 1973 to 1991, 110 patients (49 with carcinoma of the pancreatic head [Ph], 29 with distal bile duct cancer [Bi], and 32 with carcinoma of the papilla of Vater [Pv]) underwent pancreatectomy at Kanazawa University Hospital. Nodal involvement and Plx invasion were precisely evaluated by histopathologic examination.

RESULTS

Thirty-seven (76%) of the 49 patients with Ph, 20 (69%) of the 29 with Bi, and 14 (44%) of the 32 with Pv had nodal involvement. The lymph nodes most commonly involved for Ph were the posterior pancreaticoduodenal lymph nodes (numbers 13a [superior] and 13b [inferior]), the superior mesenteric lymph nodes (number 14), the paraaortic lymph nodes (number 16), and the anterior pancreaticoduodenal lymph nodes (number 17) (13a, 51%; 13b, 47%; 14, 36.7%; 16, 18.4%; 17a, 33%; 17b, 22%). In patients with Bi, lymph nodes around the hepatoduodenal ligament (number 12) and lymph nodes numbers 13a and 14 were most commonly involved (12, 27.6%; 13a, 51.7%; 14, 34.5%). In patients with Pv, lymph node numbers 13b and 14 were most frequently involved (13b, 34.4%; 14, 15.6%). No significant correlation was noted between the tumor size and nodal involvement in these three lesions. Nodal involvement was an important prognostic factor for carcinoma of the pancreatic head area. Plx invasion in these three carcinomas was observed in 61% of patients with Ph, 29% of patients with Bi, and 3% of patients with Pv.

CONCLUSIONS

Nodal involvement and Plx invasion differed significantly among carcinomas of the pancreatic head area. We believe that nodal dissection of at least group number 14 is needed for Ph, Bi, and Pv cancers. In addition, dissection of lymph nodes of number 16 and the Plx around the superior mesenteric artery and celiac axis are needed in Ph cancer. Plx dissection of the first portion of plexus pancreaticus capitalis is needed in Bi cancer.

An evaluation of radical resection for pancreatic cancer based on the mode of recurrence as determined by autopsy and diagnostic imaging

BACKGROUND

To determine the extent of dissection in curative resection for cancer of the pancreatic head, the mode of recurrence was determined at autopsy and by radiographic examinations.

MATERIALS AND METHODS

Records of 45 patients who had undergone macroscopically curative resection of carcinoma of the head of pancreas were analyzed to determined the mode of recurrence. The mode of recurrence was divided into four types: hepatic metastasis, peritoneal dissemination, retroperitoneal recurrence, and distant metastasis. Retroperitoneal recurrence was subdivided into lymph node metastasis and local recurrence, primarily neural invasion and lymphatic invasion.

RESULTS

Thirty patients experienced disease recurrence. Patients with Stage I or II disease experienced recurrence significantly less often than did patients with Stage III or IV disease (P < 0.05). Local retroperitoneal recurrence was discovered in 12 of 15 (80%) postmortem examinations, hepatic metastasis in 10 (66%), peritoneal dissemination in 8 (53%), and lymph node recurrence in 7 (47%). In 15 antemortem studies, retroperitoneal recurrence occurred most frequently (87%), followed by hepatic metastasis (53%). Almost all patients with liver metastasis also had local retroperitoneal recurrence.

CONCLUSIONS

The frequency of retroperitoneal recurrence of carcinoma of the head of the pancreas suggests that retroperitoneal resection, including nerve plexi and lymph nodes, should be included in curative resections for patients with Stage I or II pancreatic cancer.

GW170814: A Three-Detector Observation of Gravitational Waves from a Binary Black Hole Coalescence

On August 14, 2017 at 10∶30:43 UTC, the Advanced Virgo detector and the two Advanced LIGO detectors coherently observed a transient gravitational-wave signal produced by the coalescence of two stellar mass black holes, with a false-alarm rate of ≲1 in 27 000 years. The signal was observed with a three-detector network matched-filter signal-to-noise ratio of 18. The inferred masses of the initial black holes are 30.5_{-3.0}^{+5.7}M_{⊙} and 25.3_{-4.2}^{+2.8}M_{⊙} (at the 90% credible level). The luminosity distance of the source is 540_{-210}^{+130}  Mpc, corresponding to a redshift of z=0.11_{-0.04}^{+0.03}. A network of three detectors improves the sky localization of the source, reducing the area of the 90% credible region from 1160   deg^{2} using only the two LIGO detectors to 60  deg^{2} using all three detectors. For the first time, we can test the nature of gravitational-wave polarizations from the antenna response of the LIGO-Virgo network, thus enabling a new class of phenomenological tests of gravity.

Discovery of superconductivity in KTaO₃ by electrostatic carrier doping

Superconductivity at interfaces has been investigated since the first demonstration of electric-field-tunable superconductivity in ultrathin films in 1960(1). So far, research on interface superconductivity has focused on materials that are known to be superconductors in bulk. Here, we show that electrostatic carrier doping can induce superconductivity in KTaO(3), a material in which superconductivity has not been observed before. Taking advantage of the large capacitance of the self-organized electric double layer that forms at the interface between an ionic liquid and KTaO(3) (ref. 12), we achieve a charge carrier density that is an order of magnitude larger than the density that can be achieved with conventional chemical doping. Superconductivity emerges in KTaO(3) at 50 mK for two-dimensional carrier densities in the range 2.3 × 10(14) to 3.7 × 10(14) cm(-2). The present result clearly shows that electrostatic carrier doping can lead to new states of matter at nanoscale interfaces.

Cloning and functional analysis of new members of STAT induced STAT inhibitor (SSI) family: SSI-2 and SSI-3

Upon the corresponding ligand's stimulation, the cytokine receptors activate several signal pathways: JAK-STAT pathway, Ras-MAP kinase pathway and so on. Recently, we demonstrated that one of the STAT3 (signal transducer and activator of transcription-3) target genes could suppress the function of STAT3 and designated as SSI-1(STAT induced STAT inhibitor-1). SSI-1 is thought to play a critical role in negative feedback control of JAK-STAT signaling pathway. In the present study, we identified two novel human genes which products have homologous region in their SH2 domain and its COOH-terminal region to mouse SSI-1. Northern blotting analysis and functional studies demonstrated that SSI-2 and SSI-3 mRNA were also induced by cytokine stimulation and their forced expression in mouse myeloid leukemia cell, M1, suppressed the apoptotic effect of LIF, like SSI-1. We also demonstrated the structure of human SSI-1.

Short-term oral administration of L-arginine improves hemodynamics and exercise capacity in patients with precapillary pulmonary hypertension

We sought to assess the effects of oral supplementation of L-arginine, the precursor of nitric oxide (NO), on hemodynamics and exercise capacity in patients with pulmonary hypertension. Acute hemodynamic responses to oral L-arginine (0.5 g/10 kg body weight) or placebo were examined in 19 patients with primary or precapillary secondary pulmonary hypertension. Cardiopulmonary exercise tests were performed to measure peak oxygen consumption (peak V O(2)) and the ventilatory response to carbon dioxide production (V E-V CO(2) slope) before and 1 wk after treatment with L-arginine (1.5 g/10 kg body weight/d) or placebo. Oral supplementation of L-arginine significantly increased plasma L-citrulline, which indicated enhancement of NO production. Supplemental L-arginine produced a 9% decrease in mean pulmonary arterial pressure (53 +/- 4 to 48 +/- 4 mm Hg, p < 0.05) and a 16% decrease in pulmonary vascular resistance (14.8 +/- 1.5 to 12.4 +/- 1.4 Wood units, p < 0.05). L-arginine modestly decreased mean systemic arterial pressure (92 +/- 4 to 87 +/- 3 mm Hg, p < 0.05). A 1-wk supplementation of L-arginine resulted in a slight increase in peak V O(2) (831 +/- 88 to 896 +/- 92 ml/min, p < 0.05) and a significant decrease in the V E- V CO(2) slope (43 +/- 4 to 37 +/- 3, p < 0.05) without significant systemic hypotension. Hemodynamics and exercise capacity remained unchanged during placebo administration. These results suggest that oral supplementation of L-arginine may have beneficial effects on hemodynamics and exercise capacity in patients with precapillary pulmonary hypertension.

A three-dimensional nonlinear finite element model of lumbar intervertebral joint in torsion

Torsion as a cause of failure in the lumbar intervertebral joint was studied using a three-dimensional nonlinear finite element model. The role of facets and ligaments as well as the stress distributions in the posterior elements, the disk, the ligaments, and the vertebral body were examined. For physiological range of torsion, the facets carried 10 to 40 percent of the torque. The fiber stresses in the disk were the highest at the lateral margin of the outer layer of the annulus. Therefore, torsion itself is unlikely to cause posterior or posterolateral disk prolapse.

Biochemical characterization and biologic actions of two toxins (D-1 and D-2) from Clostridium difficile

Two toxins were isolated from a toxigenic strain of Clostridium difficile. The toxins were purified by gel filtration and ion-exchange column chromatography to homogeneity as judged from polyacrylamide gel electrophoresis and were designated D-1 and D-2. Toxin D-1 was lethal for mice, increased vascular permeability, and induced fluid accumulation in ligated rabbit ileal loops, and toxin D-2 displayed cytotoxicity in HeLa cells with a minimum of 1 pg of toxin. The molecular weights of toxins D-1 and D-2, as estimated by gel filtration, ranged from 550,000 to 600,000 and from 450,000 to 500,000, respectively. These toxins were heat labile and inactivated by pronase and trypsin. Amino acid analyses of both toxins showed them to be of relatively similar composition. Antisera prepared against purified toxin D-1 neutralized all of the biologic activities of toxin D-1, whereas it did not affect any of the biologic activities of toxin D-2. A sensitive latex-agglutination immunoassay was developed for screening for C. difficile toxin D-1 in patients with pseudomembranous colitis.

Perineural invasion of carcinoma of the pancreas and biliary tract

Carcinoma of the pancreatobiliary system often produces perineural invasion extending to extrabiliary and extrapancreatic sites. A surgical technique has been developed to manage this invasion and has been used since 1974. Serial sections were prepared from 90 resected specimens and examined for perineural involvement of intramural and extramural biliary plexuses as well as the pancreatic nerve plexus. Perineural invasion was seen in 34 of 40 patients with carcinoma of the common bile duct, in ten of 14 with cancer of the gallbladder and in four of 15 with carcinoma of the papilla of Vater. Invasion extended to the extramural biliary or pancreatic nerve plexuses in 24 of 40 patients with carcinoma of the bile duct. Involvement of the intrapancreatic nerves was seen in all 21 patients with carcinoma of the pancreatic head and that of the pancreatic nerve plexus in 17 of 21. Perineural invasion was often found at the most progressive margin of the tumour. The survival rate of patients with perineural invasion was low compared with that of those without such invasion, although survival of patients with perineural invasion tended to be longer after extensive resection. The perineural space should be regarded as an important route for the spread of pancreatic and biliary carcinoma.

Aortic arch reconstruction by transluminally placed endovascular branched stent graft

BACKGROUND

Recently, thoracic aortic stent grafting has emerged as an alternative therapeutic modality for patients with thoracic aortic aneurysms and aortic dissections. However, its application has been limited to descending thoracic aortic aneurysms distal to the aortic arch. We report our initial clinical experience of endovascular branched stent graft repair for aortic arch aneurysms.

METHODS AND RESULTS

Endovascular grafting with Inoue branched stent grafts was attempted for 15 patients with thoracic aortic aneurysms and aortic dissections under local anesthesia (n=14) or general anesthesia (n=1). Single-branched stent grafts were used in 14 patients, and a triple-branched stent graft in one. The branched stent grafts were delivered through a 22F or a 24F sheath under fluoroscopic guidance and implanted across the aneurysmal aortic arch. In 2 patients, the single-branched stent graft did not pass through the 22F sheath used. Complete thrombosis of the aneurysm was ultimately achieved in 11 patients (73%). Of 4 persistent leaks, 1 minor leak spontaneously thrombosed and 1 major leak was successfully treated by additional straight stent graft placement. In 1 patient, the right external iliac artery ruptured during the withdrawal of the sheath and was successfully repaired by the implantation of a straight stent graft. One patient with severe stenosis of the aortic graft section was successfully managed by additional stent deployment. Peripheral microembolization to a toe occurred in 1 patient, and cerebral infarction occurred in 1 other patient. Two patients who had failed to receive endovascular stent grafts died during an average follow-up of 12.6 months, 1 of pneumonia and the other of rupture of a concomitant abdominal aortic aneurysm.

CONCLUSIONS

This report demonstrates the technical feasibility of endovascular branched stent graft repair for aneurysms located at the aortic arch. Careful, longer follow-up and further extensive clinical trials are awaited toward establishing this technique as a recommendable alternative to surgical treatment of thoracic aortic aneurysms.