Frequency-domain interferometry for the determination of time delay between two extreme-ultraviolet wave packets generated by a tandem undulator

Synchrotron radiation, emitted by relativistic electrons traveling in a magnetic field, has poor temporal coherence. However, recent research has proved that time-domain interferometry experiments, which were thought to be enabled by only lasers of excellent temporal coherence, can be implemented with synchrotron radiation using a tandem undulator. The radiation generated by the tandem undulator comprises pairs of light wave packets, and the longitudinal coherence within a light wave packet pair is used to achieve time-domain interferometry. The time delay between two light wave packets, formed by a chicane for the electron trajectory, can be adjusted in the femtosecond range by a standard synchrotron technology. In this study, we show that frequency-domain spectra of the tandem undulator radiation exhibit fringe structures from which the time delay between a light wave packet pair can be determined with accuracy on the order of attoseconds. The feasibility and limitations of the frequency-domain interferometric determination of the time delay are examined.

Time domain double slit interference of electron produced by XUV synchrotron radiation

We present a new realization of the time-domain double-slit experiment with photoelectrons, demonstrating that spontaneous radiation from a bunch of relativistic electrons can be used to control the quantum interference of single-particles. The double-slit arrangement is realized by a pair of light wave packets with attosecond-controlled spacing, which is naturally included in the spontaneous radiation from two undulators in series. Photoelectrons emitted from helium atoms are observed in the energy-domain under the condition of detecting them one by one, and the stochastic buildup of the quantum interference pattern on a detector plane is recorded.

Double-pulsed wave packets in spontaneous radiation from a tandem undulator

We verify that each wave packet of spontaneous radiation from two undulators placed in series has a double-pulsed temporal profile with pulse spacing which can be controlled at the attosecond level. Using a Mach–Zehnder interferometer operating at ultraviolet wavelengths, we obtain the autocorrelation trace for the spontaneous radiation from the tandem undulator. The results clearly show that the wave packet has a double-pulsed structure, consisting of a pair of 10-cycle oscillations with a variable separation. We also report the characterization of the time delay between the double-pulsed components in different wavelength regimes. The excellent agreement between the independent measurements confirms that a tandem undulator can be used to produce double-pulsed wave packets at arbitrary wavelength.

Electron Wave Packet Interference in Atomic Inner-Shell Excitation

We report the observation of quantum interference between electron wave packets launched from the inner-shell 4d orbital of the Xe atom. Using pairs of femtosecond radiation wave packets from a synchrotron light source, we obtain time-domain interferograms for the inner-shell excitations. This approach enables the experimental verification and control of the quantum interference between the electron wave packets. Furthermore, the femtosecond Auger decay of the inner-shell excited state is tracked. To the best of our knowledge, this is the first observation of wave packet interference in an atomic inner-shell process, and also the first time-resolved experiment on few-femtosecond Auger decay using a synchrotron light source.

Controlling the Orbital Alignment in Atoms Using Cross-Circularly Polarized Extreme Ultraviolet Wave Packets

We report on the use of pairs of 10-cycle extreme ultraviolet wave packets with attosecond-controlled spacing emitted by individual relativistic electrons within an electron bunch passing through a tandem undulator. Based on the temporal coherent control technique with circular polarization, we succeeded in controlling the excited state alignment in the photoexcitation of helium atoms, which we verified through the observation of oscillation in fluorescence yield depending on the attosecond-controlled delay time. Our work demonstrates the potential of undulator radiation for the generation of longitudinally coherent wave packets suitable for attosecond coherent control, an application which has hitherto been hidden in the incoherent nature of the radiation pulse emitted by a bunch of electrons.

Coherent control in the extreme ultraviolet and attosecond regime by synchrotron radiation

Quantum manipulation of populations and pathways in matter by light pulses, so-called coherent control, is currently one of the hottest research areas in optical physics and photochemistry. The forefront of coherent control research is moving rapidly into the regime of extreme ultraviolet wavelength and attosecond temporal resolution. This advance has been enabled by the development of high harmonic generation light sources driven by intense femtosecond laser pulses and by the advent of seeded free electron laser sources. Synchrotron radiation, which is usually illustrated as being of poor temporal coherence, hitherto has not been considered as a tool for coherent control. Here we show an approach based on synchrotron radiation to study coherent control in the extreme ultraviolet and attosecond regime. We demonstrate this capability by achieving wave-packet interferometry on Rydberg wave packets generated in helium atoms.

Synchrotron light sources have wide range of tunable parameters like frequency, intensity. Here the authors demonstrate quantum control of Rydberg states of helium using delay controlled XUV wavepackets generated from synchrotron radiation.

Four new C19-diterpenoid alkaloids from Delphinium elatum

Diterpenoid alkaloids with remarkable chemical properties and biological activities are frequently found in plants of the genera Aconitum, Delphinium, and Garrya. Accordingly, several C19-diterpenoid alkaloid components from Delphinium elatum cv. Pacific Giant, as well as their derivatives, exhibited cytotoxic activity against lung, prostate, nasopharyngeal, and vincristine-resistant nasopharyngeal cancer cell lines. Four new C19-diterpenoid alkaloids, elapacigine (1), N-deethyl-N-formylpaciline (2), N-deethyl-N-formylpacinine (3), and N-formyl-4,19-secoyunnadelphinine (4), together with 11 known C19-diterpenoid alkaloids were isolated in a phytochemical investigation on the seeds of D. elatum cv. Pacific Giant. Their structures were elucidated by extensive spectroscopic methods including NMR (1D and 2D), IR, and MS (HRMS). Three of the new C19-diterpenoid alkaloids (2-4) and five of the known diterpenoid alkaloids were evaluated for cytotoxic activity against five human tumor cell lines.

A Remote-operated System to Map Radiation Dose in the Fukushima Daiichi Primary Containment Vessel

This paper describes the development of a submersible system based on a remote-operated vehicle coupled with radiation detectors to map the interior of the reactors at the Fukushima Daiichi nuclear power station. It has the aim oflocating fuel debris. The AVEXIS submersible vehicle used in this study has been designed as a low-cost, potentially disposable, inspection platform that is the smallest of its class and is capable of being deployed through a 150 mm diameter access pipe. To map the gamma-ray environment, a cerium bromide scintillator detector with a small form factor has been incorporated into the AVEXIS to identify radioactive isotopes via gamma-ray spectroscopy. This provides the combined system with the potential to map gamma-ray spectra and particle locations throughout submerged, contaminated facilities, such as Units 1, 2 and 3 of the Fukushima Daiichi nuclear power plant. The hypothesis of this research is to determine the sensitivity of the combined system in a submerged environment that replicates the combination of gamma radiation and water submersion but at lower dose rates.

Acute outcome of chronic total occlusion (CTO) recanalizsation in the elderly

OBJECTIVES

Percutaneous coronary intervention (PCI) of total chronic total occlusion (CTO) still remains a major challenge in interventional cardiology. There is only insignificant knowledge reported in the literature about age differences in CTO recanalization. We analyzed in this study the issue of the impact of age on procedural characteristics, complications and short-term outcome.

METHODS

Between 2012-2016 we included 440 patients. They underwent PCI for at least one CTO. Antegrade and retrograde CTO techniques were applied. The retrograde approach was used only after failed antegrade intervention. Continuous data are presented as the mean ± standard deviation; categorical data are presented as numbers and percentages unless otherwise specified. We used Twosamplet- t-test with equal variance to test the significant differences of the variables between the two cohorts.

RESULTS

Procedural success proved independently of age. There was no significant interaction between age and procedural success (p=0.5). Complication rates were low in both groups (2.7% vs. 4%; p=0,4) with no difference in statistical significance.

CONCLUSIONS

Our study suggests that in an aging society patients with severe coronary artery disease and chronical total occlusions an interventional therapy should be used more intensively. It can be performed safe and feasible.

Angular Momentum of Twisted Radiation from an Electron in Spiral Motion

We theoretically demonstrate for the first time that a single free electron in circular or spiral motion emits twisted photons carrying well-defined orbital angular momentum along the axis of the electron circulation, in adding to spin angular momentum. We show that, when the electron velocity is relativistic, the radiation field contains harmonic components and the photons of lth harmonic carry lℏ total angular momentum for each. This work indicates that twisted photons are naturally emitted by free electrons and are more ubiquitous in laboratories and in nature than ever thought.

Characterization of unexpected postural changes during robot-assisted gait training in paraplegic patients

STUDY DESIGN

This is a retrospective study.

OBJECTIVES

The objectives of this study were to categorize unexpected postural changes (UPCs) during gait training in paraplegic patients with wearable gait-assist robots, to reveal the incidence of the UPC and its time-dependent changes during initial gait training period and to investigate neurological level-specific differences.

SETTING

This study was conducted in Fujita Health University, Aichi, Japan.

METHODS

We investigated five patients (46.2±14.6 years; lesion level: T6:3, T12:2). All patients had previously achieved gait with wearable robot and walker at supervision level. The UPCs were counted for 2 years and classified according to their type. The time-course data were calculated from the incidence of UPCs for 10 days from initial gait training with the walker. The neurological level-specific differences were investigated between T6 and T12 injuries.

RESULTS

Eighty-five UPCs were observed and classified into three categories: anterior breakdown, posterior breakdown (PBD) and mal-timing. The average rate over the entire period was 0.96±0.62 (incidents/h/subject). PBD, which was defined as hyperflexion of both hip joints, occurred with the highest frequency (0.64±0.64 incidents/h/subject). During initial gait training, there was a gradual decrease in the occurrence of UPC. For neurological level-specific differences, UPCs were observed more frequently in T6 injuries (1.36±0.35 incidents/h/subject) compared with T12 injuries (0.36±0.31 incidents/h/subject).

CONCLUSION

PBDs might be the result of near collisions between the trunk of the user and the walker, which make it difficult for the users to move their trunk over an anterior stance limb. Training that is focused upon well-timed forward movements of the walker might be required to avoid the occurrence of this common UPC.

Randomized clinical trial of adjuvant chemotherapy with S-1 versus gemcitabine after pancreatic cancer resection

BACKGROUND

Randomized studies of adjuvant chemotherapy using gemcitabine suggest a survival benefit after resection of pancreatic cancer. S-1 has also been shown to prolong survival in patients with unresectable pancreatic cancer. This study compared the effects of adjuvant chemotherapy with S-1 or gemcitabine after resection of pancreatic cancer in a randomized trial.

METHODS

Patients who had undergone resection of pancreatic cancer were registered in this randomized clinical trial. The primary endpoint was disease-free survival (DFS). Expression levels of thymidylate synthase (TS) and dihydropyrimidine dehydrogenase (DPD) mRNAs in cancer tissues were measured as indicators of fluoropyrimidine sensitivity.

RESULTS

Of 57 patients registered, 29 were allocated to the S-1 group and 28 to gemcitabine. DFS tended to be better with S-1 (median 14·6 (90 per cent c.i. 8·8 to 28·4) months versus 10·5 (7·0 to 28·4) months in the gemcitabine group; P = 0·188), with a similar pattern for overall survival: 21·5 (95 per cent c.i. 14·4 to 42·3) and 18·0 (13·3 to 42·8) months respectively (P = 0·293). When patients were divided into subgroups based on high or low DPD and TS expression, those with a DPD level below the median of 0·88 or a TS level of at least 2·00 had a significant prolongation of DFS after S-1 treatment compared with gemcitabine (P = 0·008 and P = 0·035 respectively).

CONCLUSION

Overall, S-1 did not improve DFS compared with gemcitabine after pancreatic cancer resection, but there seemed to be a DFS advantage in patients with low expression of DPD or high expression of TS. Reference number: UMIN000009118 (http://www.umin.ac.jp/ctr/).

[Options and Limitations in Endovascular Therapy for Acute and Chronic Mesenteric Arterial Occlusions]

BACKGROUND

The significance of endovascular therapy for mesenteric ischaemia (MI) is being debated. Despite initially lower mortality and morbidity, inconsistent early and late results led to questions concerning indications and technical applications of the procedure.

METHODS

91 patients with MI underwent endovascular treatment in a period of 11 years. In 78 (85.7 %) patients a stent was deployed and in 13 (14.3 %) an angioplasty was performed, principally of the superior mesenteric artery (n = 81/91, 89 %). Follow-up consisted of a clinical and an ultrasound examination in all cases. Mean follow-up was 4.2 years. Our results were compared to those in the literature.

RESULTS

Endovascular treatment of the intestinal arteries accounted for 0.6 % of all vascular procedures. Seven of 91 patients (7.7 %) died after an initial PTA/stenting. The overall peri-interventional morbidity was 6.6 % (n = 6/91). Medium- to long-term complications were encountered in 20 patients (22 %), primarily during the first year (85 %). Six of 91 patients developed an in-stent stenosis (6.6 %) and 14/91 patients (15.4 %) stent occlusion. Additionally 2 dislocated stents (2.2 %) and an arterial perforation with bleeding into the mesentery (1.1 %) were seen. Although 3 of these 20 patients were successfully treated with an additional PTA or stenting (15.0 %; n = 3/91, 3.3 %), surgical conversion was necessary in 9 (n = 9/20, 45 %; n = 9/91, 9.9 %). The postoperative mortality was respectively 22.2 % (n = 2/9; n = 2/91, 2.2 %). In the case of acute MI, endovascular procedures are only indicated for patients without peritonitis. In chronic MI, the indication for endovascular treatment depends on the type of occlusion and the vascular anatomy. Despite favourable early results, the outcome of endovascular treatment deteriorates with time reaching a 1-year patency rate of 63 % in a multicentre analysis. This leads to secondary procedures in 30 %. A surgical conversion carries a high mortality.

CONCLUSION

The endovascular treatment of intestinal artery disease cannot be considered the treatment of choice, it is rather an alternative method in patients with functional or local contraindications to surgery. Life-long follow-up is necessary to prevent stent complications with fatal consequences. A prospective randomised study concerning the evaluation of the advantages and disadvantages of surgical and endovascular therapy of intestinal artery occlusive disease is required.

Microbunching instability in relativistic electron bunches: direct observations of the microstructures using ultrafast YBCO detectors

Relativistic electron bunches circulating in accelerators are subjected to a dynamical instability leading to microstructures at millimeter to centimeter scale. Although this is a well-known fact, direct experimental observations of the structures, or the field that they emit, remained up to now an open problem. Here, we report the direct, shot-by-shot, time-resolved recording of the shapes (including envelope and carrier) of the pulses of coherent synchrotron radiation that are emitted, and that are a "signature" of the electron bunch microstructure. The experiments are performed on the UVSOR-III storage ring, using electrical field sensitive YBa2Cu3O(7-x) thin-film ultrafast detectors. The observed patterns are subjected to permanent drifts, that can be explained from a reasoning in phase space, using macroparticle simulations.

Three-year results after directional atherectomy of calcified stenotic lesions of the superficial femoral artery

OBJECTIVE

To investigate the 3-year outcome of patients with peripheral arterial disease (PAD) and heavily calcified stenotic lesions of the superficial femoral artery after directional atherectomy.

MATERIALS AND METHODS

Fifty-three patients (mean age 67 ± 10 years; 18 females, 35 males, TASC B and C, mean lesion length 7.9 ± 3.5 cm) with PAD (Rutherford 2-6) were enrolled into this prospective monocentric study. In total, 59 calcified lesions of the superficial femoral artery were treated with the Silverhawk atherectomy device (Covidien, Plymouth, MN, USA). Patients were followed-up for 36 months with a 6-month interval to perform clinical re-evaluation, including measurement of maximum walking distance and ankle-brachial index (ABI) as well as duplex-sonography.

RESULTS

The primary success rate of the procedure was 92 %. In five cases (8 %), additional balloon-PTA and/or stent-PTA was necessary. Procedure-related embolization occurred in seven cases (12 %), which were all successfully treated by aspiration. The primary patency rate after 3 years was 55 %. Median Rutherford score decreased significantly from 5 to 0 after 36 months (p < 0.001). At the same time, the ABI increased from 0.65 to 1.12 (not significant). The limb-salvage rate after 3 years was 87 %.

CONCLUSION

In this subgroup of patients with POD and calcified stenotic lesions, atherectomy was successfully applied to decrease the plaque burden. Results after 3 years showed a significant decrease of Rutherford score with persistent improvement of ABI and reasonable patency rate.

[Ureteroarterial fistula - pathogenesis, diagnostics, and therapeutic outcome]

Although ureteroarterial fistulas are rare, they result in a high mortality because of the massive urogenital haemorrhage. The diagnosis is often difficult even when invasive measures are applied. Including the ureteroarterial fistula in the diagnostic process in cases of macrohaematuria with a positive medical history can be helpful. A ureteroarterial fistula typically develops in pa-tients who have undergone pelvic surgery and radiation as well as after long-term ureteral stents. Patients are usually multimorbid. The treatment of choice consists of fistula exclusion by stent graft deployment in the iliac artery and application of a ureteral stent or a ureterostomy. The significance of surgical treatment is diminishing. The long-term results of endovascular treatment, however, are inconsistent because of stent infections and recurrent bleeding. Therefore, close patient surveillance and cooperation among the treating specialists is necessary.·

Malignant bladder pheochromocytoma with SDHB genetic mutation

A 30-year-old man presented with micturition pain and was diagnosed with a submucosal tumor in the right wall of the bladder with metastasis to the right obturator lymph node. Transurethral resection led to a diagnosis of invasive malignant pheochromocytoma. Radical cystectomy, neobladder reconstruction and bilateral iliac lymph node dissection were performed. Genetic analysis revealed succinate dehydrogenase B-associated hereditary pheochromocytoma/paraganglioma syndrome. 10 months after the operation, he had no evidence of recurrence.

Photon-induced positron annihilation lifetime spectroscopy using ultrashort laser-Compton-scattered gamma-ray pulses

High-energy ultrashort gamma-ray pulses can be generated via laser Compton scattering with 90° collisions at the UVSOR-II electron storage ring. As an applied study of ultrashort gamma-ray pulses, a new photon-induced positron annihilation lifetime spectroscopy approach has been developed. Ultrashort gamma-ray pulses with a maximum energy of 6.6 MeV and pulse width of 2.2 ps created positrons throughout bulk lead via pair production. Annihilation gamma rays were detected by a BaF2 scintillator mounted on a photomultiplier tube. A positron lifetime spectrum was obtained by measuring the time difference between the RF frequency of the electron storage ring and the detection time of the annihilation gamma rays. We calculated the response of the BaF2 scintillator and the time jitter caused by the variation in the total path length of the ultrashort gamma-ray pulses, annihilation gamma rays, and scintillation light using a Monte Carlo simulation code. The positron lifetime for bulk lead was successfully measured.

Total removal of huge chondrosarcoma of the skull base with facial nerve resection and reconstruction

Chondrosarcomas of the skull base are locally aggressive tumours, and radical surgical resection is often difficult because of involvement of important neural structures in the skull base. We report the successful total resection of a huge skull base chondrosarcoma extending both intra- and extracranially. The tumour involved the left mastoid process, entire petrous bone, jugular foramen, posterior fossa and the parapharyngeal space. Since the facial nerve in the fallopian canal was totally involved by the tumour, the nerve was sacrificed and reconstructed using a great auricular nerve graft. The removal of the tumour was radical and complete. The functional recovery of the reconstructed facial nerve was excellent. The patient has almost fully recovered from the other neurological symptoms and has been free of tumour recurrence for 4 years after surgery.

A scoring system for the assessment of angiographic findings in non-occlusive mesenteric ischemia (NOMI)

PURPOSE

To establish a standardized scoring system for angiographic findings in patients with non-occlusive mesenteric ischemia (NOMI).

MATERIALS AND METHODS

In 36 patients (mean age: 72 years), 53 angiographies of the superior mesenteric artery (SMA) were performed for suspected NOMI after cardiac or major aortic surgery. All examinations were performed using a standardized DSA technique. Two experienced radiologists performed a consensus reading blinded to the clinical information, on two occasions with an interval of two weeks. In order to investigate the reproducibility of the criteria, the images were assessed once by an intensivist and a medical student. Image analysis was performed with respect to vessel morphology, reflux of contrast medium into the aorta, small bowel parenchymal contrast enhancement and distension and the delay between arterial injection and portal vein filling.

RESULTS

Almost perfect intra-observer correlation was obtained for the assessment of the contrast medium reflux (κ = 0.82) and substantial correlation for the time of portal vein filling (κ = 0.66). Moderate correlations were obtained for the vessel morphology (κ = 0.51), small bowel enhancement (κ = 0.63) and distension (κ = 0.53). Contrast medium reflux into the aorta (κ = 0.77 and 0.63) and the time of portal vein filling (κ = 0.42 and 0.58) resulted in the highest inter-observer correlations between the radiologists and the intensivist as well as the radiologists and the student.

CONCLUSION

In patients with suspected NOMI, using our scoring system yields high intra- and inter-observer correlations, allowing a standardized evaluation of angiographic findings.

Pressure pain threshold of mucosa after tooth extraction under removable denture bases

This study explored the pressure pain threshold (PPT) of the mucosa after tooth extraction. The PPTs of the wounded mucosa of eight volunteer subjects were observed at 7, 30, and 90 days after tooth extraction. The PPTs at 30 days and 90 days were approximately two and three times higher respectively, than those at 7 days. As time passed, the values for the PPTs after tooth extraction increased in all regions. At 90 days after tooth extraction, the PPTs are about 97% recovered compared to the PPTs of the contralateral points.

Effect of linoleic acid albumin in a dilution solution and long-term equilibration for freezing of bovine spermatozoa with poor freezability

Despite normal eucrasia, mating desire and semen quality, sire bulls sometimes have spermatozoa with poor freezing tolerance. This study assessed effects of the addition of linoleic acid albumin (LAA) and long-term (LT) equilibrium to frozen semen on their sperm freezing tolerance. Immediately after collection using an artificial vagina and a breeding mount, semen was diluted with yolk citrate buffer; then, it was cooled slowly to 4°C during more than 5 h. Equilibrium treatment at 4°C was applied using the same extender supplemented with glycerol. Semen of bull A, with low sperm freezing tolerance, was treated with 1 mg/ml of LAA added to the first extender. The equilibrium treatment at 4°C was prolonged to 30 h. Significantly higher motility rates were obtained for the LT + LAA-treated sperm before and after freezing-thawing. However, for semen of bulls B and C with normal sperm freezing tolerance, the LT + LAA treatment barely exhibited a small effect on the motility rate. Almost no difference was found among bulls A, B and C in the motility rates of LT + LAA-treated sperm after freezing-thawing. No difference of fertility was apparent on LT + LAA-treated frozen sperm in comparison with normal sperm in embryonic collection and in vitro fertilization. It was not an aberration of fertility in vivo or in vitro. In addition, the conception rate of artificial insemination did not have a difference, and a normal calf was obtained. Results show that addition of LAA to an extender for frozen bovine spermatozoa and 30 h of low-temperature equilibrium might improve the motility of freezing-thawing spermatozoa with poor freezability. Sperm exhibited normal fertilization capability and ontogenic capability.

Subintimal revascularization of chronic iliac artery occlusions using a reentry-catheter

PURPOSE

To demonstrate the value of a Reentry-Catheter for true lumen access after subintimal revascularization of chronic iliac artery occlusions.

MATERIALS AND METHODS

Subintimal revascularization was performed in 5 patients (mean age: 67 ± 12 years; female: 3, male: 2) with total iliac artery occlusion (TASC B to D), but without gaining access to the true lumen distal to the occlusion. Subsequently, a Reentry-Catheter was used to establish reentry and a new subintimal tract. Patients were followed up after 6, 12 and 24 months for clinical re-evaluation to determine the Rutherford score and the ankle brachial index (ABI). In addition, duplex ultrasound was performed to evaluate vessel patency.

RESULTS

The primary technical success rate was 100 %. In all cases angioplasty was followed by stent placement to establish the subintimal tract. The mean Rutherford score decreased from 3.6 ± 0.9 to 0.33 ± 0.57 after 24 months, while the ABI increased from 0.67 ± 0.06 to 1.2 ± 0. Vessel patency was observed in all patients available for follow-up examinations.

CONCLUSION

The Reentry-Catheter reliably allowed access to the true lumen after subintimal revascularization of occluded iliac arteries. Results in this small patient cohort showed a significant reduction in the Rutherford score, increase in the ABI, and a good patency rate after two years.

Refined human artificial chromosome vectors for gene therapy and animal transgenesis

Human artificial chromosomes (HACs) have several advantages as gene therapy vectors, including stable episomal maintenance, and the ability to carry large gene inserts. We previously developed HAC vectors from the normal human chromosomes using a chromosome engineering technique. However, endogenous genes were remained in these HACs, limiting their therapeutic applications. In this study, we refined a HAC vector without endogenous genes from human chromosome 21 in homologous recombination-proficient chicken DT40 cells. The HAC was physically characterized using a transformation-associated recombination (TAR) cloning strategy followed by sequencing of TAR-bacterial artificial chromosome clones. No endogenous genes were remained in the HAC. We demonstrated that any desired gene can be cloned into the HAC using the Cre-loxP system in Chinese hamster ovary cells, or a homologous recombination system in DT40 cells. The HAC can be efficiently transferred to other type of cells including mouse ES cells via microcell-mediated chromosome transfer. The transferred HAC was stably maintained in vitro and in vivo. Furthermore, tumor cells containing a HAC carrying the suicide gene, herpes simplex virus thymidine kinase (HSV-TK), were selectively killed by ganciclovir in vitro and in vivo. Thus, this novel HAC vector may be useful not only for gene and cell therapy, but also for animal transgenesis.

[Multimodal approach in coincidence of covered ruptured abdominal aortic aneurysm and aortocaval fistula]

HISTORY AND ADMISSION FINDINGS

A 71-year-old patient had been referred to our hospital with the diagnosis, made by angio-computed tomography (CTA), of a covered ruptured abdominal aortic aneurysm (AAA) resulting in an aortocaval fistula (ACF).

INVESTIGATIONS

The physical examination revealed macrohematuria and high-output heart failure with increasing circulatory insufficiency.

DIAGNOSIS, TREATMENT AND COURSE

An open endovascular procedure was not possible because the AAA had extended into both internal iliac arteries. A bifurcated prosthesis connecting to both femoral arteries was then successfully implanted and the infrahepatic aortocaval fistula closed by a patch through the AAA. Ischemic colitis, diagnosed on postoperative day 2 (POD 2), was successfully treated with antibiotics. CTA, done on POD 5, revealed a small residual ACF, filling retrogradely from the right external iliac artery via the surgically closed aneurysmal sack. Closure of the residual ACF was achieved with an Amplatz occluder inserted into the right external iliac artery, introduced percutaneously via the right femoral artery. The postoperative course was uneventful and the patient discharged on POD 13.

CONCLUSION

The coincidence of AAA and ACF is rare. However, the morbidity and mortality are high and require early diagnosis and immediate treatment.

[MR imaging of lymph nodes using Gadofluorine M: feasibility in a swine model at 1.5 and 3T]

PURPOSE

To investigate the potential of Gadofluorine M for targeted lymph node imaging in a human size animal model and on a clinical MR scanner at 1.5 and 3 T.

MATERIALS AND METHODS

Pelvic and cervical lymph nodes in a swine model were investigated prior to and 24 hours after intravenous administration of 50 micromol/kg body weight Gadofluorine M, an experimental contrast agent. MR imaging was carried out on clinical 1.5 T and 3 T whole-body MR systems using clinically available coils and T 1-weighted sequences. The signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) with respect to the surrounding tissue were assessed and compared using the Student's t-test. The Gd concentration in the lymph nodes (n = 43) was measured post mortem by Inductively Coupled Plasma-Atomic Emission Spectroscopy (ICP-AES).

RESULTS

Gadofluorine M allowed for high signal and high contrast visualization of lymph nodes in all stations on post-contrast images with a significantly increased SNR and CNR (SNR pelvic lymph nodes post vs. pre: 46 +/- 7 vs.14 +/- 3, SNR cervical lymph nodes post vs. pre: 105 +/- 64 vs. 32 +/- 21; CNR pelvic lymph node vs. muscle post vs. pre 28 +/- 5 vs. 0.2 +/- 0.5, CNR cervical lymph node vs. muscle post vs. pre 76 +/- 53 vs. 11 +/- 15, p < 0.05 for all comparisons). The SNR and CNR in the pelvis were further improved using 3 T compared to 1.5 T scanners (SNR lymph nodes 3 T vs. 1.5 T 84 +/- 6 vs. 46 +/- 7, CNR lymph node vs. muscle 3 T vs. 1.5 T 53 +/- 9 vs. 28 +/- 5 respectively, p < 0.05). A high concentration of Gd in the lymph nodes was found (149 +/- 25 mmol Gd/L).

CONCLUSION

Gadofluorine M accumulates in the lymph nodes and allows for selective targeted high contrast MR imaging of lymph node tissue in a large animal model using clinically available MR imaging techniques. 3 T further improves SNR and CNR compared to 1.5 T.