Development of inverted pendulum thrust stand with spring-shaped wire for high power electric thrusters

Pendulum thrust stands are used to measure the thrust of electric propulsion systems for spacecraft. A thruster is mounted on a pendulum and operated, and the pendulum displacement due to thrust is measured. In this type of measurement, the pendulum is also affected by nonlinear tensions due to wiring and piping that deteriorate the accuracy of the measurement. This influence cannot be ignored in high power electric propulsion systems because complicated piping and thick wirings are required. Therefore, to reduce the influence of tension due to wires and tubes, we developed an inverted pendulum-type thrust stand with pipes and wirings as springs. In this paper, we first derive the design guidelines for spring-shaped wires; the necessary conditions for sensitivity, responsivity, spring shape, and electric wire were formulated. Next, a thrust stand was designed and fabricated based on these guidelines, and the performance of the stand was evaluated through calibration and thrust measurements using a 1 kW-class magneto-plasma-dynamics thruster. The sensitivity of the thrust stand was 17 mN/V, the normalized standard deviation of the variation of the measured values owing to the structure of the thrust stand was 1.8 × 10^-3, and the thermal drift during the long-time operation was ∼4.5 × 10^-3 mN/s.

Outcome of pitavastatin versus atorvastatin therapy in patients with hypercholesterolemia at high risk for atherosclerotic cardiovascular disease

BACKGROUND

There has been no report about outcome of pitavastatin versus atorvastatin therapy in high-risk patients with hypercholesterolemia.

METHODS

Hypercholesterolemic patients with one or more risk factors for atherosclerotic diseases (n = 664, age = 65, male = 54%, diabetes = 76%, primary prevention = 74%) were randomized to receive pitavastatin 2 mg/day (n = 332) or atorvastatin 10 mg/day (n = 332). Follow-up period was 240 weeks. The primary end point was a composite of cardiovascular death, sudden death of unknown origin, nonfatal myocardial infarction, nonfatal stroke, transient ischemic attack, or heart failure requiring hospitalization. The secondary end point was a composite of the primary end point plus clinically indicated coronary revascularization for stable angina.

RESULTS

The mean low-density lipoprotein cholesterol (LDL-C) level at baseline was 149 mg/dL. The mean LDL-C levels at 1 year were 95 mg/dL in the pitavastatin group and 94 mg/dL in the atorvastatin group. There were no differences in LDL-C levels between both groups, however, pitavastatin significantly reduced the risk of the primary end point, compared to atorvastatin (pitavastatin = 2.9% and atorvastatin = 8.1%, HR, 0.366; 95% CI 0.170-0.787; P = 0.01 by multivariate Cox regression) as well as the risk of the secondary end point (pitavastatin = 4.5% and atorvastatin = 12.9%, HR = 0.350; 95%CI = 0.189-0.645, P = 0.001). The results for the primary and secondary end points were consistent across several prespecified subgroups. There were no differences in incidence of adverse events between the statins.

CONCLUSION

Pitavastatin therapy compared with atorvastatin more may prevent cardiovascular events in hypercholesterolemic patients with one or more risk factors for atherosclerotic diseases despite similar effects on LDL-C levels.

123I-MIBG myocardial scintigraphy for the diagnosis of DLB: a multicentre 3-year follow-up study

BACKGROUND AND PURPOSE

We previously reported the usefulness of iodine-123 metaiodobenzylguanidine (¹²³I-MIBG) myocardial scintigraphy for differentiation of dementia with Lewy bodies (DLB) from Alzheimer's disease (AD) in a cross-sectional multicentre study. The aim of this study was, by using reassessed diagnosis after 3-year follow-up, to evaluate the diagnostic accuracy of ¹²³I-MIBG scintigraphy in differentiation of probable DLB from probable AD.

METHODS

We undertook 3-year follow-up of 133 patients with probable or possible DLB or probable AD who had undergone ¹²³I-MIBG myocardial scintigraphy at baseline. An independent consensus panel made final diagnosis at 3-year follow-up. Based on the final diagnosis, we re-evaluated the diagnostic accuracy of ¹²³I-MIBG scintigraphy performed at baseline.

RESULTS

Sixty-five patients completed 3-year follow-up assessment. The final diagnoses were probable DLB (n=30), possible DLB (n=3) and probably AD (n=31), and depression (n=1). With a receiver operating characteristic curve analysis of heart-to-mediastinum (H/M) ratios for differentiating probable DLB from probable AD, the sensitivity/specificity were 0.77/0.94 for early images using 2.51 as the threshold of early H/M ratio, and 0.77/0.97 for delayed images using 2.20 as the threshold of delayed H/M ratio. Five of six patients who were diagnosed with possible DLB at baseline and with probable DLB at follow-up had low H/M ratio at baseline.

CONCLUSIONS

Our follow-up study confirmed high correlation between abnormal cardiac sympathetic activity evaluated with ¹²³I-MIBG myocardial scintigraphy at baseline and the clinical diagnosis of probable DLB at 3-year follow-up. Its diagnostic usefulness in early stage of DLB was suggested.

TRIAL REGISTRATION NUMBER

UMIN00003419.

220 NONHUMAN PRIMATE EMBRYONIC STEM CELLS SIMILAR TO THE BIOLOGICAL PROPERTIES OF MOUSE EMBRYONIC STEM CELLS

Human and mouse embryonic stem (ES) cells are derived from the inner cell mass of preimplantation blastocysts and human ES cells were long thought to be equivalent to mouse ES cells, despite clear morphological difference and different signalling pathways to maintain their pluripotency between these two ES cell types. Mouse ES cells depend on leukemia inhibitory factor (LIF) and bone morphogenic protein 4 (BMP4) signalling, whereas their human counterparts rely on basic fibroblast growth factor (bFGF) and activin A signalling. The biggest difference of two ES cells is the ability of chimera formation and mouse ES cells can contribute chimera but primate ES cells fails to do that. Monkey ES cells in primates only can be tested for chimera formation in vivo due to the ethical issue and cynomolgus monkey is the most common nonhuman primate to be used for the safety study of drug discoveries. The objective of this study was to develop novel cynomolgus monkey ES cells that have similar biological properties with mouse ES cell and our ultimate goal is to establish germline competent nonhuman primate ES cells. Ovarian stimulation and oocyte collection were carried out for the derivation of ES cells as previously described by Torii et al. Briefly, GnRH (0.9 mg/head) was administered to cynomolgus monkey and two weeks later, a micro infusion pump (iPRECIO™, Primetech Corp) contains FSH was implanted subcutaneously. Follicular aspiration was then performed 40 h after hCG injection and metaphase II oocytes were fertilized by intracytoplasmic sperm injection (ICSI). Cynomolgus monkey ES cells were then established under mouse ES cell conditions such as LIF/STAT signalling and a dome tree-dimensional (3D) morphology nonhuman primate ES cells were selected. On the other hands, ES cells that were established with the presence of basic FGF showed conventional layer-type morphology. Dome-type ES cells express pluripotent transcriptional factors such as Oct-3/4, Nonog and Sox2 as same as layer-type ES cells and both ES lines were capable of multilineage differentiations in vitro after embryoid body formation. Dome-type nonhuman ES cells can also form teratomas and differentiated into all three germ layers when grafted into immunodeficiency mice. For fluorescent gene delivery to nonhuman primate ES cells, feeder-free condition was applied and CAG-GFP vector was transfected into ES cells using Neon electroporation system (Invitrogen Inc.) for the tracing ES cells in the transplantation study. In this study, we have established dome-type ES cell lines that similar to mouse ES cells in morphology and signalling pathway. Dome-type nonhuman primate ES cells express pluripotent gene markers and prove their pluripotency both of in vitro and in vivo, in addition, these modifications would be important to create germline competent ES cells.

127 OVARIAN STIMULATION IN CYNOMOLGUS MONKEYS BY A CONTROLLED RELEASE OF FOLLICULAR-STIMULATING HORMONE UTILIZING A MICRO-INFUSION PUMP

We have established an indoor artificial breeding system for the cynomolgus monkey in an effort to increase the number of MII oocytes that are required for enhanced reproductive efficiency. A conventional ovarian stimulus method requires FSH to be administered to monkeys intramuscularly once a day for 9 days. Recently, a novel implantable and programmable micro-infusion pump (iPRECIO™, Primetech Corp, Tokyo, Japan) has been introduced for small laboratory animals to infuse fluids continuously for long periods of time in vivo. We adapted this micro-infusion pump to administer FSH to cynomolgus monkeys. In this study, we optimized the controlled-release program of FSH for the appropriate ovarian stimulation. First, laparoscopic evaluation was performed to identify animals that had small, underdeveloped follicles and gonadotropin-releasing hormone (0.9 mg animal–1; Leuplin, Takeda, Osaka, Japan) was administered to all selected animals. Two weeks later, iPRECIO™ containing FSH (Gonapure, ASKA, Tokyo, Japan) was implanted subcutaneously and the continuous infusion was started at 15.0 IU kg–1 per day. Five days after implantation, follicular development was evaluated by laparoscopy and the infusion rate was adjusted based on follicular profile (high level: reduced to 12.5 IU kg–1 per day, n = 11; middle level: maintained at 15.0 IU kg–1 per day, n = 47; low level: increased to 20.0 IU kg–1 per day, n = 30). Four days later, hCG (400 IU kg–1, IM) was administered and follicular aspiration was performed 40 h later. In the control group (n = 6), FSH (25.0 IU kg–1 per day) was injected intramuscularly once a day for 9 days, followed by an hCG injection. Oocytes were collected and evaluated and MII oocytes were fertilized by intracytoplasmic sperm injection. Injected oocytes were cultured for 7 days in CRML-1066 medium supplemented with 20% bovine serum at 38°C, with 5% CO2 and 5% O2 in air and blastocyst development was evaluated. Data were analysed by a two-sided t-test. All animals treated with the controlled-release FSH using iPRECIO™ showed significantly higher MII maturation rates (mean: 59.4%, 22/37; P < 0.05) than those of the control group (MII rate: 46.3%, 19/41); however, there was no significant difference among the different FSH release programs. Blastocyst development rates of the test group were also significantly higher than those of the control group (test: 52.0%, control: 28.1%; P < 0.05); however, there was no significant difference among the different FSH programs. This controlled-release system did not require daily injections to the animal, which would be beneficial for decreasing stress. Further, the required dose of FSH using iPRECIO™ was much less than that of the conventional multiple-injection method. These results indicated that controlled release of FSH utilising an iPRECIO™ pump can be customized based on follicular profile and has financial and animal care advantages compared with the conventional method.

39 CLONAL OFFSPRING DERIVED FROM SEPARATED BLASTOMERES IN CYNOMOLGUS MONKEYS (MACACA FASCICULARIS)

There are no reports of cloning by embryo splitting in the cynomolgus monkey, but production of genetically identical monkeys would have tremendous implications for biomedical research, especially for immunological studies, production of disease models, and behavioral science. Cloning would also reduce the number of animals required for the above research by increasing experimental reproducibility. In this study, we tried to produce cynomolgus monkey offspring by embryo splitting and embryo transfer. Controlled ovarian stimulation and oocyte recovery have been previously described by Torii et al. (2000 Primates 41, 39–47). Cumulus-free mature oocytes were fertilized by intracytoplasmic sperm injection. Single spermatozoa were individually immobilized by scoring their tails and picking them up with the injection pipette. The denuded oocyte was held by the holding pipette with the polar body in the 12 o'clock position. The injection pipette was then inserted at the 3 o'clock position and was introduced into the cytoplasm, breaking the ooplasmic membrane by pulling gently. One spermatozoon was injected into the cytoplasm. The injected oocytes were cultured at 38�C in 5% CO2, 5% O2 and 90% N2 in CMRL-1066 medium (Invitrogen, Grand Island, NY, USA) containing 20% calf serum (CS, Invitrogen) for 2–3 days. Splitting was performed using 4- to 7-cell-stage embryos. The zona pellucida was disrupted with acidic Tyrode's solution, and individual blastomeres were separated from the zona-free embryos by 0.25% trypsin-EDTA with added CaCl2 (<1 min). After transferring the zona-free embryos into TALP-HEPES medium, blastomeres were dissociated by pipetting with a 40–50 µm micropipette 4–5 times. These blastomeres were then transferred into empty zonae that had been produced from immature oocytes by the aspiration of ooplasm with a micromanipulator. Sixteen embryos underwent blastomere separation and a total of 33 split embryos were produced. After being cultured for 2–3 h in CMRL-1066 medium containing 20% CS, 30 of these split embryos, comprising 1–4 blastomeres each, were transferred into the oviducts of 23 fertile surrogate mothers at 0 to 5 days after ovulation. Pregnancy was confirmed in two animals (8.7%; 2/23) by ultrasound approximately 30 days after transfer. The pregnancies were uneventful and two normal healthy babies were born without any assistance 159 days after transfer. The low pregnancy rate could be due to the presence of fewer cells in the smaller split embryos, the ruptured zona pellucida, or the in vitro micromanipulation of embryos during blastomere separation and reconstruction. Here we report the first production of viable cloned offspring produced by blastomere separation in the cynomolgus monkey. Since we have previously succeeded in establishing ES cell lines from isolated blastomeres, in the future we will be able to produce genetically identical monkeys from a single 4- to 8-cell-stage embryo using those ES cell lines and the embryo splitting technique.

256 EFFECT OF EPIDERMAL GROWTH FACTOR ON IN VITRO MATURATION OF CYNOMOLGUS MONKEY (MACACA FASCICULARIS) OOCYTES

Collected oocytes include not only mature oocytes (metaphase II: MII), but also immature oocytes (germinal vesicle: GV, and metaphase I: MI). To establish a dependable artificial indoor breeding program in cynomolgus monkeys, we are planning to carry out in vitro maturation (IVM) using GV and MI oocytes. In this study, we attempted to determine whether different types of feeder layers and epidermal growth factor (EGF) were effective for IVM. Cumulus–oocyte complexes (COCs) were collected from ovaries of 4–10-year-old female cynomolgus monkeys stimulated by the combination of FSH (25 IU kg–1 × 9 days) and hCG (400 IU kg–1) (Torii 2000 Primates 39, 399–406). Oocytes were classified by morphological features: oocytes retaining an intact germinal vesicle nucleus (GV); oocytes that had undergone germinal vesicle breakdown without polar body formation (MI); and oocytes with a first polar body (MII). GV and MI oocytes were co-cultured on monkey cumulus cells (MCC), monkey follicular ovarian cells (MFOC), monkey oviductal cells (MOC), or human solubilized amnion product (HSAP), with TCM-199+10% fetal bovine serum containing epidermal growth factor (EGF; 10 ng mL–1 or 20 ng mL–1). The maturation rate from GV to MII oocytes was 6.7% (MCC), 18.0% (MFOC), 35.7% (MOC), and 28.6% (HSAP) (Table 1). Although higher maturity was observed in MOC and HSAP, the effect of EGF was not found in co-cultures using any feeder layers. The maturation rate from MI to MII oocytes was 33.3% (MCC), 27.8% (MFOC), 55.6% (MOC), and 44.0% (HSAP) (Table 1). The highest maturation rate from GV and MI was observed in co-cultures using MOC. The maturation rate from MI to MII oocytes in the presence of 10 ng mL–1 EGF was 75.0% (MCC) and 73.7% (HSAP) (Table 1), whereas the rate in the presence of 20 ng mL–1 EGF was 59.1% (MCC), 64.3% (MFOC), 92.3% (MOC), and 60.0% (HSAP) (Table 1). Thus, the best maturation rate was a co-culture using MOC as a feeder layer with 20 ng mL–1 EGF. According to our results, maturation rate during IVM depends on the cellular type of feeder layers and the concentration of EGF. EGF is especially effective for maturity from MI to MII oocytes, but not from GV to MI or MII oocytes. Thus, IVM should be carred out under optimal culture conditions, including suitable feeder layer and media plus supplements. In the future, it is important that intracytoplasmic sperm injection be carried out using in vitro-matured MII oocytes for establishment of an artificial indoor breeding program in cynomolgus monkeys. Table 1. Number of matured oocytes co-cultured with different feeder layers and EGF

60 INFLUENCE OF HOECHST STAINING FOR NUCLEAR TRANSFER ON PARTHENOGENETIC EMBRYOS IN CYNOMOLGUS MONKEYS (MACACA FASCICULARIS)

Nonhuman primates are valuable animal models for the study of human diseases, and somatic cell nuclear transfer (SCNT) is an important method for establishing tailor-made embryonic stem (ES) cells and transgenic animals in these model species. However, there have been few reports on SCNT in nonhuman primates. Moreover, the development of cloned blastocysts could be influenced by any chemical reagents and manipulations used in this technique. In this study we compared blastocyst developmental rates with and without Hoechst staining. Metaphase II (MII) oocytes were collected from hormone-treated adult female cynomolgus monkeys (Macaca fascicularis) under laparoscopic observation (Torii et al. 2000 Primates 41, 39–47). A pseudo-SCNT procedure, which consisted of cytochalasin B treatment, cytoplasm removal, and dissection of the oocyte membrane, was performed on MII oocytes either in the presence of (Experiment 1; Ex1) or in the absence of Hoechst 33342 (Experiment 2; Ex2). Hoffman modulation contrast microscopy was used in Ex1 and Nomarski differential interference contrast (DIC) was used in Ex2. In Ex1, cumulus-free MII oocytes were treated with Hoechst 33342 (5 mg mL–1; Sigma Chemical Co., St. Louis, MO, USA) for 5 min and the following pseudo-SCNT procedure was carried out: cytochalasin B (CB, 5 µg mL–1; Sigma) for 20 min, removal of a small amount of cytoplasm (pseudo-EN), and then dissection of the oocyte cytoplasmic membrane (pseudo-IN) under Hoffman modulation contrast microscopy. In Ex2, CB treatment, pseudo-EN, and pseudo-IN were performed under Nomarski DIC microscopy. After treatment, these oocytes were activated by parthenogenetic stimulation. Parthenogenesis was induced by 5-m ionomycin (Sigma) for 2 min and 2 mm 6-dimethylaminopurine (Sigma) for 4 h. As a control, cumulus-free MII oocytes were activated by only parthenogenetic stimulation, without the above manipulations. These activated oocytes were cultured in CMRL-1066 medium containing 20% calf serum at 38�C in 5% CO2, 5% O2, and 90% N2 for 7–8 days. The rates of development to blastocyst stage were 14% (1/7) in Ex1, 30% (3/10) in Ex2, and 29% (2/7) in the control. The developmental rate of parthenotes to the blastocyst stage in Ex2 was greater than that in Ex1 and similar to the control. These results suggest that treatment of cynomolgus monkey oocytes with Hoechst staining possibily decreases development to the blastocyst stage. Therefore, enucleation under Nomarski DIC will be a good alternative to Hoechst staining and could improve the potential development of nonhuman primate SCNT embryos.

290 A CYNOMOLGUS MONKEY EMBRYONIC STEM CELL LINE DERIVED FROM A SINGLE BLASTOMERE

The establishment of most embryonic stem (ES) cell lines requires the destruction of embryos. Some ES cell lines in mice and humans are currently derived from a single blastomere, so that remaining blastomeres can still develop into fetuses. However, the procedures currently in use for establishing these lines are very complicated, and other ES cell lines from the same species are needed (Chung et al. 2006 Nature 439, 216–219; Klimanskaya et al. 2006 Nature 444, 481–485). The objective of this study was to devise a method simpler than those previously described for establishing ES cell lines from a single blastomere in the cynomolgus monkey. Controlled ovarian stimulation and oocyte recovery have been described previously by Torii et al. (2000 Primates 41, 39–47). Cumulus-free mature oocytes were fertilized by intracytoplasmic sperm injection (ICSI), and then cultured at 38�C in 5% CO2, 5% O2 for 2 days. The zona pellucida of 4- to 5-cell-stage embryos was disrupted using acidic Tyrode's solution, and individual blastomeres were separated from the denuded embryos using trypsin. These blastomeres were cultured on mitomycin-C-treated mouse embryonic fibroblasts and ES medium containing adrenocorticotropic hormone (ACTH) (Ogawa et al. 2004 Genes to Cells 9, 471–477). After the formation of initial outgrowths, half of the medium was changed every other day until the outgrowths reached approximately 100 cells. Passage of putative monkey ES cells was performed by mechanical dispersion of the colonies and transfer to fresh feeders every 3–4 days until there were enough cells for enzymatic dispersion. One stable ES cell line was obtained from two 4- or 5-cell-stage embryos using ES medium containing ACTH. The morphology of this ES cell colony was consistent with the monkey ES cell colony previous described by Suemori et al. (2001 Dev. Dynamics 222, 273–279). The ES cell line was passaged more than 17 times, and the morphology of the ES cell colony did not differ between the first and seventeenth passages. The ES cells showed normal karyotype and retained pluripotency markers for primate ES cells including octamer-binding protein 4 (Oct-4), stage-specific embryonic antigen (SSEA)-4, tumor-rejection antigen (TRA)-1-60, and TRA-1-81. We are presently confirming whether this ES cell line possesses potencies to differentiate in all three embryonic germ layers using both an in vitro assay and teratoma formation. Here we showed that cynomolgus monkey ES cells can be derived from a single blastomere, without co-culturing another ES cell line, as has been done in previous studies on mice and humans. This method allows the establishment of ES cell lines from a single blastomere, leaving the other blastomeres available for embryo transfer. Thus, the method described here is simpler than previously described methods and alleviates some ethical concerns.

155 LAPAROSCOPIC EVALUATION OF OVARIAN REACTION TO HORMONE STIMULATION IN CYNOMOLGUS MONKEYS (MACACA FASCICULARIS)

Oocyte collection is a key step to development of a system for modeling human regenerative medicine and assisted reproductive technology in cynomolgus monkeys (Macaca fascicularis), but collecting oocytes at a suitable developmental stage (metaphase II) is difficult. Metaphase II (MII) oocytes can be collected from cynomolgus ovaries stimulated by hormone injection. In this study, we developed a useful method for collecting a large number of MII oocytes by monitoring the morphology and size of ovaries with laparoscopic observation. Controlled ovarian stimulation and oocyte recovery in mature cynomolgus monkeys have been previously described by Torii et al. (2000 Biochemistry 39, 3197–3205). Beginning at menses, levels of estrogens were down-regulated by the subcutaneous injection of a GnRH antagonist (Leuplin, 0.9 mg animal-1; Takeda Chemical Industries, Ltd., Osaka, Japan). Two weeks later, human follicle stimulating hormone (FSH, Fertinorm, 25 IU kg-1; Serono, Canton Zug, Switzerland) was administered for 9 days. On the day after that of the last FSH administration, human chorionic gonadotropin (hCG, Puberogen, 400 IU kg-1; Sankyo Co., Ltd., Tokyo, Japan) was intramuscularly injected. Follicular aspiration was performed at 404-41 hours post-hCG injection. Oocyte collection was monitored using a 3-mm laparoscope attached to a video system. Oocytes were aspirated from the follicles using a 20-guage needle. Follicle development of the ovary was rated morphologically as A (small follicles), B (many small follicles), or C (many large follicles), and size relative to the uterus was rated as 1 (no response), 2 (smaller), 3 (equal), or 4 (larger) at oocyte collection. Regarding morphology, the highest ratio of MII/total oocytes was obtained from B–C ovaries (rating of 2 ovaries, one each left or right with a rating of B or C, n = 8, 26.9 � 22.4, 70.7%), followed by B–B (n = 21, 19.5 � 14.3, 55.9%), and C–C (n = 19, 10.6 � 5.8, 51.9%). No MII oocytes were collected from A–A (n = 1, 0%) ovaries. Ovaries appeared to be over-stimulated in the ovaries rated C–C but under-stimulated in B–B. Regarding ovary size, the highest ratio of MII/total oocytes was obtained from 4–4 (both ovaries with rating of 4, n = 10, 21.9 � 11.2, 68.8%), followed by 3–3 (n = 21, 19.1 � 14.3, 58.2%), and 2–2 (n = 9, 11.6 � 6.5, 53.3%). No MII oocytes were collected from 1–1 ovaries (n = 1, 0%). The number of MII oocytes collected was directly related to ovary size: more MII oocytes were collected from larger ovaries. These data demonstrate that the number of oocytes collected is directly related to ovary size. Our results suggest that the ratio of MII oocytes can be predicted by the morphology and the size of ovaries. In addition, we found that ovarian development can be controlled by adjusting FSH dosage. Therefore, laparoscopic observation of ovaries during FSH treatment and adjusting FSH dosage are necessary to collect MII oocytes efficiently.

[Analysis of the action of dextran sulfate as a prophylaxis for peritoneal cancer metastasis, and its acting mechanism]

Although peritoneal cancer metastasis has the highest frequency of postoperative recurrence among digestive organ malignant tumors, there is no still decisive treatment. Dextran sulfate (DS) as a prophylaxis for cancer metastasis was examined with respect to its effect on cultured cells. DS was made to act on a strong adhesive neoplasm cell, and the action and acting mechanism were examined with respect to 1. readhesiveness, 2. cell cycle, and 3. gene analysis. The results suggest that: i) Once tumor cells are detached by DS, the free cells do not attach even when DS is removed, and ii) DS causes the cells to stop in the G1/G0 phase.

Combined use of electrosurgical incisions and balloon dilatation for the treatment of refractory postoperative pyloric stenosis

BACKGROUND

Drug therapy plus balloon dilatation without gastroscopic incision does not always relieve postoperative pyloric stenosis.

METHODS

Five patients with postoperative pyloric stenosis whose symptoms did not improve with drug therapy and balloon dilatation underwent a combination of gastroscopic incision and balloon dilatation. Two or 3 small radial incisions were made in the stenotic muscle of the pylorus electrosurgically at gastroscopy. Then the stenotic muscle layer was loosened and split bluntly along the incisions with balloon dilatation for 15 to 20 minutes. One week later, the combination procedure or balloon dilatation alone was repeated to prevent restenosis.

RESULTS

In the 5 patients, the stenosis was improved with the combination therapy. No complications were observed.

CONCLUSIONS

Combined use of gastroscopic incision and balloon dilatation may be considered for patients with refractory pyloric stenosis caused by surgical truncal vagotomy.

Dextran sulfate inhibits injured abdominal wall-specific tumor implantation in mice

Tumor recurrence is often seen at sites where the peritoneum has been injured during surgery for gastrointestinal malignancies. It is thought that malignant cells released from the tumor during surgery implant in the sites of injury in the abdominal wall and cause tumor recurrence. Here we use dextran sulfate (DS) as an antagonist to cell adhesion for preventing implantation of i.p. seeded malignant cells, thus suppressing the recurrent tumor formation often observed at the site of injury in postoperative abdominal walls. DS was tested for anti-adherent activity against B-16 melanoma cells to injured abdominal wall specimens ex vivo and showed the capacity to significantly impair B-16 melanoma cell adherence compared to controls without DS. DS was also tested for the activity to prevent i.p. seeded B-16 melanoma cells from implanting in the site of injury in the abdominal wall in vivo and DS prevented B-16 melanoma cells from implanting in the sites of injury in the abdominal wall. In the test for the activity to improve survival in mice after B-16 melanoma was inoculated i.p., DS improved the survival of mice as compared to the controls without DS. We conclude that DS may be useful in preventing surgically promoting tumor implantation at sites of injury in post-operative abdominal wall treated for gastrointestinal malignancies.

Local injection of anti-cancer drugs bound to carbon particles for early gastric cancer--a pilot study

BACKGROUND/AIMS

A new dosage formulation consisting of an anti-cancer drug bound to activated carbon particles was developed for a local injection against early gastric cancer so that the dosage formulation yields chemotherapeutic effects selectively to the lymph node metastases as well as to the primary lesion.

METHODOLOGY

As a pilot study, the new dosage formulation, total of 50-200 mg of methotrexate only or total of 200 mg of methotrexate plus 8 mg of mitomycin C, was injected into the primary lesions and the adjacent gastric wall of 8 patients with early gastric cancer, guided by a gastrofiberscope before gastrectomy. The surgically resected specimens were examined histologically for the therapeutic effects on the primary lesion and its nodal metastasis.

RESULTS

The therapeutic effects were seen in 2 of 4 lymph node metastases (50%) and 5 of 8 of the primary lesions (63%), as confirmed histologically with degeneration and/or necrosis.

CONCLUSIONS

Preoperative local injection of the new dosage formulation will be useful to give chemotherapeutic effects on the potential metastases in the regional nodes as well as to the primary lesion.

Extensive gastrectomy and carbon-adsorbed mitomycin C for gastric cancer with peritoneal metastases. Case reports of survivors and their implications

BACKGROUND/AIMS

Extensive gastrectomy, defined as gastrectomy with complete omentectomy and extended lymphadenectomy, improves the survival of gastric cancer patients with peritoneal metastases, even though peritoneal metastasis is considered the end-stage of cancer. MMC-CH, a new dosage formulation of mitomycin C, extended the survival of rabbits with peritoneal carcinomatosis as compared to aqueous mitomycin C.

METHODOLOGY

We retrospectively reviewed 114 patients who underwent gastrectomy for gastric cancer with peritoneal metastases.

RESULTS

Six patients survived for more than 5 years after the therapy out of 63 patients treated with MMC-CH therapy and extensive gastrectomy for gastric cancer with P1, i.e., metastases to the adjacent peritoneum but no metastasis to the distant peritoneum, or P2, i.e., a few metastases to the distant peritoneum. However, there were no 5-year survivors in patients with P3, i.e., numerous metastases to the distant peritoneum, or in patients treated with incomplete omentectomy, limited lymphadenectomy and no MMC-CH therapy.

CONCLUSIONS

The results imply that gastric cancer patients with P1 or P2 have a possible chance to survive more than 5 years when treated with MMC-CH therapy and extensive gastrectomy.

Effect of extensive lymph node dissection on the survival of early gastric cancer

BACKGROUND/AIMS

A retrospective analysis of 628 cases of early gastric cancer was performed to evaluate prognostic significance of extensive lymph node dissection.

METHODOLOGY

The patients were assigned to either D0/D1 (n=177) group or D2/D3 group (n=451) according to the extent of lymph node dissection and the survival of the two groups was compared.

RESULTS

The survival rate of D2/D3 group was significantly higher than D0/D1 group in the case of both including and excluding unrelated cause of death (p<0.0001 and p<0.005, respectively).

CONCLUSIONS

Though early gastric cancer is excellent prognostic disease, very few numbers of patients with recurrence really remain. Our data show extensive lymph node dissection was effective to prolong the survival of patients with early gastric cancer.

Endoscopic incision and balloon dilatation for cicatricial anastomotic strictures

BACKGROUND/AIMS

Endoscopic incision or balloon dilatation is common therapy for cicatricial anastomotic strictures after gastrointestinal surgery. These therapies are not always effective.

METHODOLOGY

There were 6 patients who failed either endoscopic incision or balloon dilatation alone and who underwent a combination of the two therapies. Two or three small radial incisions were made in the scar of the stricture with the endoscopic electrocautery under direct vision with fiberscopy. Then, the incisions were split bluntly and the stenosis was dilated over 15-20 minutes with balloon-dilator. This procedure was performed once or twice at a 2-week interval.

RESULTS

In 5 of the 6 patients, the stenosis was improved in subjective criteria and objective symptoms. In the last patient, only objective improvement was noted. There were no complications.

CONCLUSIONS

Endoscopic incision plus balloon dilatation is an effective and safe treatment for cicatricial anastomotic strictures which have failed either therapy alone.

Complete omentectomy and extensive lymphadenectomy with gastrectomy improves the survival of gastric cancer patients with metastases in the adjacent peritoneum

BACKGROUND/AIMS

The omentum is the site where peritoneal metastases occur most frequently. It has not been shown whether complete resection of the omenta during gastrectomy improves the survival of gastric cancer patients with macroscopic peritoneal metastases.

METHODOLOGY

We retrospectively analyzed 126 patients who underwent gastrectomies for gastric cancer with peritoneal metastases but without hematogenous metastases. The 126 patients were stratified according to their grade of peritoneal metastases into three groups: the P1 patients (patients with peritoneal metastases in the adjacent peritoneum but not in the distant peritoneum); the P2 patients (patients with a few peritoneal metastases in the distant peritoneum); and the P3 patients (patients with many metastases in the distant peritoneum). In each group, the survival and clinicopathological characteristics were compared between patients treated by complete resection of the greater omentum and the lesser omentum plus extensive lymphadenectomy during gastrectomy, versus patients treated by incomplete resection of the omenta and non-extensive lymphadenectomy during gastrectomy.

RESULTS

Complete omentectomy and extensive lymphadenectomy during gastrectomy improved survival significantly only in the P1 patients. Other clinicopathological characteristics did not differ between them.

CONCLUSION

Complete omentectomy and extensive lymphadenectomy is recommended in patients with peritoneal metastases in the adjacent peritoneum but not in the distant peritoneum.

Therapeutic effects of 5-fluorouracil microspheres on peritoneal carcinomatosis induced by Colon 26 or B-16 melanoma in mice

The delivery formulation 5-FU-MS [5-fluorouracil (5-FU) incorporated in microspheres composed of a poly(glycolide-co-lactide) matrix] slowly releases 5-FU over 3 weeks. 5-FU-MS delivers higher concentrations of the drug to the i.p. tissues for a longer period of time with lower blood plasma concentrations than does an aqueous 5-FU solution and reduces toxicity. In this study, we evaluated the therapeutic effects of 5-FU-MS on peritoneal carcinomatosis in mice. Four days after an i.p. inoculation with Colon 26 or B-16 PC melanoma, 5-FU at 200 mg/kg was administered i.p. as 5-FU-MS or as an aqueous solution of 5-FU. 5-FU-MS extended the survival of mice bearing Colon 26 or B-16 PC melanoma significantly better than the equivalent dose of aqueous 5-FU solution.

Prevention of peritoneal metastasis of cancer with dextran sulfate--an experimental study in mice

Peritoneal metastases occur most often in the greater omentum, where tumor implantation sites are densely distributed. We used dextran sulfate (S-Dex) as an anti-cell-adherence agent to prevent i.p. seeded malignant cells from causing peritoneal metastases. S-Dex was tested for its anti-adherent activity against B-16 melanoma cells on plastic, and was examined for its ability to prevent implantation in the omentum and to improve survival in mice after B-16 melanoma was inoculated i.p. S-Dex prevented B-16 melanoma cells from adhering to the plastic wall. S-Dex reduced the number of B-16 melanoma cells implanted into the greater omentum and improved the survival of mice inoculated with B-16 melanoma cells. We conclude that S-Dex attenuated peritoneal metastases when B-16 melanoma cells were seeded i.p.

[Endoscopic local injection of anticancer drugs bound to carbon particles for treatment of upper digestive tract cancers--clinical trials]

A new dosage formulation consisting of anticancer drugs bound to carbon particles was developed for treating cancers of the upper digestive tract, and is designed to distribute higher levels of anticancer drug to the regional lymph nodes and at the injection site, as compared to a drug in aqueous solution form. Thirteen patients with histologically proven carcinoma (8 with superficial esophageal cancer and 5 with early or proper muscle layer-infiltrating gastric cancer), in whom surgical treatment was contraindicated, received intra- and peritumoral injection of the new dosage formulation (total dose of 35-100 mg of peplomycin or 250-500 mg of methotrexate) guided by esophago- or gastro-fiberscope. Eleven of these 13 patients are currently alive, 12-64 months after therapy, or they died without evidence of recurrence 12-98 months after the treatment. One patient has remained cancer-free for 37 months after a second course of the therapy given to treat a recurrence found 26 months after the first treatment. Another patient has a recurrent tumor 9 months after the therapy and is now going to undergo a second course of treatment. Side effects were not severe and well-tolerable.

[Visualising lymph nodes by aclarubicin bound to activated carbon particles in breast cancer surgery]

A new dosage formulation (ACR-CH), composed of aclarubicin (ACR) bound to fine activated carbon particles, has been developed for the treatment of lymph node metastases in breast cancer. ACR-CH is designed to (a) adsorb a great amount of aclarubicin and desorb in a free state; (b) distribute a greater amount of ACR for a longer period of time selectively to the regional lymph nodes; (c) be decreased in the systemic toxicity; and (d) enhance its therapeutic effect on lymph node metastases. In this clinical trial in 20 patients with breast cancer, ACR-CH was injected intra- and peritumorally just before operation for breast cancer, and we examined the extent of blackened nodes produced by ACR-CH. ACR-CH blackened about 70% of the axillary lymph nodes with cancer metastasis as well as the nodes without metastasis. In conclusion, ACR-CH will be useful for dissection of lymph nodes by visualizing the nodes during operation for breast cancer.

Selective drug delivery to peri-tumoral region and regional lymphatics by local injection of aclarubicin adsorbed on activated carbon particles in patients with breast cancer--a pilot study

ACR-CH, which consists of aclarubicin (ACR) adsorbed onto activated carbon particles, was developed for locoregional chemotherapy for breast cancer. Thirty patients with breast cancer received an ACR (10 mg) injection intra- and peri-tumorally, either as ACR-CH or as ACR aqueous solution (ACR-AQ) 5 min before the operation for breast cancer. The ACR concentrations were significantly higher in the peritumoral regions and regional lymph nodes, and were also significantly lower in the blood plasma in patients given ACR-CH versus patients given ACR-AQ.

Endoscopic local injection of a new drug delivery formulation, anticancer drug bound to carbon particles, for digestive cancers: pilot study

A new dosage formulation consisting of an anticancer drug bound to activated carbon particles was developed for the treatment of digestive cancer in patients in whom operation is contraindicated. The new formulation is designed to distribute higher levels of anticancer drug to the regional lymph nodes and at the injection site compared to distribution of the drug in aqueous solution. In 12 patients with histologically proven carcinoma (7 with superficial esophageal cancer and 5 with early or proper muscle layer-infiltrating gastric cancer), an anticancer drug bound to carbon particles (total dose, 40-100 mg peplomycin or 250-500 mg methotrexate per person) was injected endoscopically into the primary lesions. Eleven of the 12 patients are currently alive, 12-64 months after therapy, or they died without evidence of cancer 12-98 months after the treatment. One patient has remained cancer-free for 32 months after a second course of the new formulation therapy given to treat a recurrence detected 26 months after the first treatment. Endoscopic injection of this new dosage formulation seems to control these digestive cancers in patients in whom operation is contraindicated.

Selective delivery of 5-fluorouracil (5-FU) to i.p. tissues using 5-FU microspheres in rats

A new formulation has been developed for the delivery of 5-fluorouracil (5-FU) in treating peritoneal carcinomatosis. The new formulation (5-FU-MS) involves the incorporation of 5-FU into microspheres composed of a poly(glycolide-co-lactide) matrix. The incorporated 5-FU is released slowly over a 3 week period. We investigated the drug distribution and pharmacokinetics of 5-FU in rats receiving an i.p. injection of 5-FU-MS or aqueous 5-FU solution. The concentration of 5-FU was higher in the i.p. tissues (omentum and mesentery) and lower in the extraperitoneal tissues (blood plasma, lung and heart) in rats given 5-FU-MS than in rats given the aqueous 5-FU solution. Pharmacokinetic analysis showed that the area under the curve (AUC) was significantly greater in the omentum and the mesentery than in other tissues of rats given 5-FU-MS. There was no significant difference in the AUC in the tissues of rats given the aqueous 5-FU solution.

[Therapy of carcinomatous peritonitis by the angiogenesis inhibitor TNP-470 in mice: analysis of timing and doses for intraperitoneal administration]

In order to perform therapy for carcinomatous peritonitis by a new angiogenesis inhibitor, TNP-470, we investigated the effective timing and the optimal doses for intraperitoneal administration using two mice models. In both carcinomatous peritonitis models caused by M 5076 tumor and B 16 melanoma, the early administration of TNP-470 within one week after tumor inoculation extended the survival times of the mice receiving the drugs, whereas the administration of TNP-470 one week or later after inoculation did not affect the survival time. However, there were significant differences in the effective therapeutic doses of TNP-470 between the two models. It is important to select the best timing and doses for intraperitoneal administration of TNP-470 based on the state of angiogenesis and the sensitivity of the tumor tissues to TNP-470.

[Endoscopic injection of methotrexate bound to activated carbon particles in the treatment of gastric cancer]

A new dosage formulation (MTX-CH), composed of fine activated carbon particles absorbing methotrexate (MTX), distributes concentrated MTX for long periods of time to the regional lymph nodes as well as to the injection site, in animal experiments. MTX-CH would enhance the therapeutic effects not only on the primary lesion but also on the lymphatic metastasis. As clinical trials, (A) in five patients with early gastric cancer, MTX-CH at 50 to 200 mg/person of MTX was injected endoscopically in and around the primary lesion before operation. Surgically removed specimens showed that three out of the 5 primary lesions had disappeared or were necrotic, and the remaining two lesions had shrunk. (B) Three patients with contraindication to surgery received the endoscopic injection of MTX-CH. The MTX-CH injected at 250 to 1,500 mg/person into and around the primary lesion of relatively early gastric cancer resulted in the complete disappearance of the primary lesions for 14 to 24 months up to the present time without enlargement of the lymph nodes. It was thought that local injection of MTX-CH will be effective therapy, especially for gastric cancer with potential lymphatic metastasis in patients with contraindications to surgery.

Significance of coronary artery tone assessed by coronary responses to ergonovine and nitrate

The coronary artery response to ergonovine (EM) and nitrate of the proximal, middle and distal segments of the three major coronary artery branches and the main trunk was quantified in 67 patients without coronary spasm and in 69 patients with coronary spasm without significant organic stenosis. The changes in control diameter and diameter after EM administration compared to diameter after nitrate were used as the index of coronary artery tone. EM increased coronary artery tone regardless of the occurrence of coronary spasm (p less than 0.01). In all segments, basal coronary artery tone was greater in patients with spasm than in patients without spasm (p less than 0.01) in a way similar to the coronary responses to EM (p less than 0.01). In patients with spasm, both coronary artery tone after EM and basal coronary tone were greater in the spastic segments than in the nonspastic segments (p less than 0.01), which were greater than those in patients without spasm (p less than 0.01). Our data suggest that patients with spasm may have increased basal tone, and that coronary artery spasm may be based on increased coronary tone. Clinically, evaluation of the basal tone and response to EM in the entire coronary artery tree may be useful for predicting the presence of coronary artery spasm.

Delayed cardiac tamponade and hemothorax induced by an acupuncture needle

We report a 52-year-old man who presented with cardiac tamponade a few years after accidental breakage of an acupuncture needle that had not been removed. Thoracotomy showed a hemopericardium with penetration of the pulmonary artery by the very fine needle which was barely detected on the chest roentgenogram. This lesion was not suspected on the basis of roentgenography, two-dimensional echocardiography, or computed tomography, but was detected by the presence of other thick needles in the neck, chest and abdomen. This case showed a possible threat of 'stealthy' and migrating foreign bodies, such as very fine acupuncture needles.

[Coronary artery tone assessed by the administration of ergonovine maleate and nitrates]

Angiographic changes caused by administering ergonovine maleate (EM) and nitrates were quantitated in 136 patients without significant coronary artery disease. Percent coronary artery (CA) narrowing was calculated in 67 patients with a negative EM test (Group A) and 69 patients with a positive EM test (Group B) as follows: (Formula; see text) In both groups, coronary artery narrowing before and after EM did not differ among the proximal, middle or distal segments of each coronary artery. The measurements of the right coronary artery were greater than those of the left anterior descending artery (p less than 0.01 after EM, p less than 0.05 before EM), and those of the left main trunk were markedly less than those of the other coronary arteries (p less than 0.01). In both groups, coronary narrowing after EM administration was greater than before administration (p less than 0.01). Initial coronary narrowing in Group B was also greater than in Group A (p less than 0.01), similar to the responses for EM. In 19 patients with coronary artery spasm provoked by EM coronary artery narrowing before and after EM was 37 +/- 12% and 69 +/- 23% for coronary arteries with spasm, and 30 +/- 13% and 42 +/- 16% for those without spasm. Not only after, but also before EM administration, coronary narrowing was greater in the arteries with spasm than in those without spasm (p less than 0.01). Furthermore, the arteries without spasm showed greater sensitivity to EM and nitrates than did the arteries of the control patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Two cases of coronary artery spasm induced by indocyanine green

There is no evidence in the literature that coronary artery spasm is induced by indocyanine green (ICG). In the present report, we describe 2 cases who developed chest pain with transient ST elevation on electrocardiograms after intravenous administration of ICG.

Effects of pirmenol hydrochloride on the spontaneous action potentials and membrane current systems of rabbit sinoatrial node cells

The electrophysiologic effects of pirmenol hydrochloride on rabbit sinoatrial node cells were examined and compared with those of several class I antiarrhythmic agents. At 1 microM, pirmenol decreased the heart rate and the rate of diastolic depolarization and increased the action potential duration at half-amplitude. Above 10 microM, the agent also decreased the maximum rate of rise (Vmax) and the action potential amplitude significantly. The order of the inhibitory potency on Vmax was apridine greater than 711389-S greater than pirmenol greater than mexiletine greater than tocainide. With respect to the current systems, pirmenol decreased the slow inward current (Isi) and the time-dependent potassium outward current (IK). The agent also prolonged the recovery time constant of Isi without any changes in the decay process of the tail current (IK). These findings suggest that pirmenol depresses the spontaneous discharge of the sinoatrial node through a decrease in Isi and Ik.

Effects of amoxapine on electrophysiological properties of rabbit sinoatrial node

The effects of amoxapine on membrane potentials and membrane currents of rabbit sinoatrial node were studied using the double microelectrode voltage clamp method. Amoxapine (greater than 1 mumol.litre-1) decreased the heart rate and the maximum rate of rise and the rate of diastolic depolarisation in a dose dependent manner. Above 3 mumol.litre-1, amoxapine also decreased the action potential amplitude and prolonged the action potential duration at half amplitude. These electrophysiological changes induced by amoxapine were relatively reduced in a high calcium medium (extracellular calcium concentration 4.0 mmol.litre-1). In voltage clamp experiments amoxapine depressed the slow inward current, the time dependent potassium current, and the hyperpolarisation activated inward current. The major effect, however, was considered to be a reduction of the slow inward current. It is concluded that amoxapine produced an inhibitory action on the electrical activity of sinoatrial node, and this action is mainly explained by an inhibition of calcium influx through the cell membrane.

[Metastatic tumor of the heart from gall bladder cancer detected by echocardiography: a case report]

Cardiac metastases have been reported increasingly partly because of the longevity of cancer patients, but its antemortem diagnosis is frequently missed. This is due to the nonspecific clinical manifestations or relative lack of characteristic signs which are masked by the underlying disease. This is a report of a 42-year-old man diagnosed as having a metastatic cardiac tumor by echocardiography, six months after operation for squamous cell carcinoma of the gall bladder. Echocardiography revealed abnormal structures in the regions of the posterior and lateral walls of the left ventricle and interventricular septum, suggesting metastatic tumors. The cytological findings of a fine-needle aspiration biopsy specimen were squamous cell carcinoma. The patient died of cardiac failure eight months after the echocardiographic diagnosis. At autopsy, the abnormal structures in the heart were identified as cardiac metastatic tumors from gall bladder cancer. Reports of cardiac metastasis of gall bladder cancer is very rare (0-3%). The myocardial metastasis may have a more serious prognostic importance than the primary neoplasm itself; thus, its definite diagnosis is mandatory.

Inhibitory action of 711389-S on the electrical activity of rabbit sinoatrial node

The effects of 711389-S (0.1-10 mumol.litre-1) on membrane potentials and currents of rabbit sinoatrial node preparations were studied using a conventional double microelectrode voltage-clamp method. The agent 711389-S decreased the heart rate, the maximum rate of depolarisation, and the amplitude of the action potential and increased the action potential duration in a dose dependent manner. The slope of the diastolic depolarisation was also reduced. Of the current systems of sinoatrial node, 711389-S depressed the slow inward current (Isi), the potassium outward current (IK), and the hyperpolarisation activated current (Ih) dose dependently. The kinetics of IK were not altered significantly by the drug. It is concluded that 711389-S does not have an effect on a single current system but that the drug exerts a depressant effect on the electrical activity of the sinoatrial node.

Estimation of catecholamine potencies on the myocardium by means of a new method

A simple method is described for evaluating the potencies of catecholamines on the slow response of myocardium. Catecholamines depolarize guinea pig ventricular muscle cells exposed to the high K+ (27 mmol/l) Tyrode's solution containing 0.2 mmol/l Ba through an increase in slow channel conductance. Higher concentrations of catecholamines in addition induce spontaneous action potentials. This model was used to estimate and compare catecholamine potencies on myocardium. Catecholamine concentrations needed for depolarization alone or for depolarization plus automatic activity were taken as basis for comparison. The order of potency obtained by means of this new method was: l-isoproterenol greater than l-adrenaline greater than or equal to dl-noradrenaline greater than or equal to dobutamine greater than or equal to dopamine. This is similar to the order reported with other methods.

[The clinical significance of an oscillating flap in the acute stage of dissecting aneurysm: report of three cases]

The important two-dimensional echocardiographic finding of dissecting aneurysm in the acute stage is characterized by the presence of an oscillating intimal flap which is thought to be of highly diagnostic value. This report describes about three cases with dissecting aneurysm in which an oscillating flap was transiently observed. In Case 1 (62-year-old female), an oscillating flap observed in the aortic arch seven hours after the onset was not detected three days later. A flap in Case 2 (65-year-old male) which had been present in the descending aorta three hours after the onset of illness disappeared two days later. In Case 3 (55-year-old male), only an intimal flap without fine oscillation was demonstrated in the abdominal aorta by echocardiography performed three days after the onset of illness. In the acute phase of dissection, the echocardiographic detection of an oscillating flap seems to depend on the time of the study after the attack.