Heating by an electron Bernstein wave in a spherical tokamak plasma via mode conversion

The first successful high power heating of a high dielectric constant spherical tokamak plasma by an electron Bernstein wave (EBW) is reported. An EBW was excited by mode conversion (MC) of an mode cyclotron wave injected from the low magnetic field side of the TST-2 spherical tokamak. Evidence of electron heating was observed as increases in the stored energy and soft x-ray emission. The increased emission was concentrated in the plasma core region. A heating efficiency of over 50% was achieved, when the density gradient in the MC region was sufficiently steep.

Clinical outcomes of EMR for gastric tumors: historical pilot evaluation between endoscopic submucosal dissection and conventional mucosal resection

BACKGROUND

EMR is currently a standard treatment for mucosal gastric tumors. Endoscopic submucosal dissection (ESD) has been developed for en bloc resection.

OBJECTIVE

We evaluated the clinical outcomes of ESD compared with conventional EMR.

DESIGN

Not applicable.

SETTING

A historical control study was performed between EMR and ESD.

PATIENTS

EMR of 245 gastric tumors was performed in 229 patients. Lesions were divided into two groups. Conventional EMR was performed in group A from February 1999 to June 2001, and ESD was performed in group B from July 2001 to March 2004. Group B was divided into subgroups: subgroup B-1 underwent ESD from July 2001 to March 2003 and subgroup B-2 from April 2003 to March 2004.

INTERVENTIONS

All lesions were resected with conventional EMR or with ESD.

MAIN OUTCOME MEASUREMENTS

En bloc resection rate, rate in completeness of resection, required time, remnant ratio, and complications were evaluated.

RESULTS

With regard to lesions >10 mm in size, the en bloc resection rate and the rate in completeness of resection of group B was significantly higher than that of group A (p < 0.01). Although the required time was longer in group B than A (p < 0.01), it was shorter in subgroup B-2 compared with B-1 (p < 0.05) with lesions < or =10 mm in size. The remnant ratio and perforation rate were not different between groups.

LIMITATIONS

Not applicable.

CONCLUSIONS

The en bloc resection rate was better with ESD than with conventional EMR. The required time was longer in ESD, but this disadvantage might be improved with experience.

Acquired lesions of the corpus callosum: MR imaging

In this pictorial review, we illustrate acquired diseases or conditions of the corpus callosum that may be found by magnetic resonance (MR) imaging of the brain, including infarction, bleeding, diffuse axonal injury, multiple sclerosis, acute disseminated encephalomyelitis, Marchiafava-Bignami disease, glioblastoma, gliomatosis cerebri, lymphoma, metastasis, germinoma, infections, metabolic diseases, transient splenial lesion, dilated Virchow-Robin spaces, wallerian degeneration after hemispheric damage and focal splenial gliosis. MR imaging is useful for the detection and differential diagnosis of corpus callosal lesions. Due to the anatomical shape and location of the corpus callosum, both coronal and sagittal fluid-attenuated inversion recovery images are most useful for visualizing lesions of this structure.

Brainstem and cerebellar changes after cerebrovascular accidents: magnetic resonance imaging

We illustrate the various types of secondary degeneration in the brainstem and/or cerebellum detected on magnetic resonance (MR) images obtained after cerebrovascular accidents. The changes include: (a) ipsilateral nigral degeneration after striatal infarction; (b) Wallerian degeneration of the pyramidal tract in the brainstem after supratentorial pyramidal tract or motor cortex injury; (c) Wallerian degeneration of the corticopontine tract in the brainstem after frontal lobe infarction; (d) ipsilateral brainstem atrophy and crossed cerebellar atrophy due to an extensive supratentorial lesion; (e) ipsilateral superior cerebellar peduncle atrophy, contralateral rubral degeneration, contralateral inferior olivary degeneration and ipsilateral cerebellar atrophy after dentate nucleus hemorrhage; (f) ipsilateral inferior olivary degeneration after pontine tegmentum hemorrhage; (g) bilateral wallerian degeneration of the pontocerebellar tracts after ventromedial pontine infarction or basis pontis hemorrhage; and (h) ipsilateral cerebellar atrophy after middle cerebellar peduncle hemorrhage.

Observation of nonlinear coupling between small-poloidal wave-number potential fluctuations and turbulent potential fluctuations in Ohmically heated plasmas in the JFT-2M tokamak

Two types of electrostatic modes with small-poloidal wave numbers (approximately 1 and 10-15 kHz) are observed in the edge region of Ohmically heated plasmas in the JFT-2M tokamak. The envelope of the higher frequency coherent mode is modulated at the frequency of the lower frequency mode. A bispectral analysis revealed that a significant nonlinear coupling among the two types of fluctuations and the broadband background turbulent potential fluctuations occurs inside the last closed magnetic flux surface, suggesting that a nonlinear process such as the parametric-modulational instability is involved.

Clinical features, effectiveness of drug-based treatment, and prognosis of new daily persistent headache (NDPH): 30 cases in Japan

Although new daily persistent headache (NDPH) is considered to be one of the most refractory headaches to pharmacological treatment, the effectiveness of drug-based treatment, and the prognosis of NDPH have not been well studied. The purpose of this study is to evaluate the effectiveness of pharmacological treatment of NDPH. Seventeen men and 13 women who met the IHS diagnostic criteria for NDPH, were treated for five years from November 1997 to October 2002, and whose headache conditions were entirely available for reference as of October 2003 were investigated in Toyonaka Municipal Hospital. Mean age at onset 35.0 years (range 13-73 years). The onset of headache occurred in relation to a stressful life event in six (20%) patients and any precipitating events could not be identified in 24 (80%) patients. For treatment, muscle relaxants were first administered and if no effect was observed, tricyclic antidepressants, selective serotonin reuptake inhibitors, and antiepleptic drugs were subsequently administered. Results of the drug-based treatments in the 30 cases were 'very effective' for eight (27%) cases, 'moderately effective' for one (3%) case, 'mildly effective' for six (20%) cases, and 'not effective' for 15 (50%) cases. According to the survey on the phone for the patients who did not improve to the level of 'mildly effective' or better and did not come back to our institution as of October 2003, there were no cases found to have spontaneously improved to the level of 'mildly effective' or better. These results suggest that NDPH is highly recalcitrant to the treatments with poor prognosis and better treatments are needed.

Spontaneous Thrombosis of a High-flow Carotid-Cavernous Fistula after Failed Transarterial Balloon Occlusion

SUMMARY

A 62-year-old man with a traumatic high-flow right carotid-cavernous fistula was treated by transarterial balloon occlusion technique. However, because of the relatively small size of the fistula, the balloon could not enter into the cavernous sinus via the fistula. During the procedure, the shunt flow decreased significantly, and we stopped the procedure. Follow-up angiography performed 14 days after the procedure showed complete occlusion of the fistula with a small residual pseudoaneurysm. One year later, the pseudoaneurysm had decreased in size. Repeated transient decrease and stagnancy of blood flow at the fistula during the balloon procedure may have played an important role in the thrombosis in this patient.

Intussusception due to intestinal anisakiasis: a case report

This report describes our experience of intussusception due to intestinal anisakiasis which was treated by laparoscopy-assisted surgery. The unique sonographic findings of this complication were a pseudokidney sign and a target sign with an edema of Kerckring's folds in the intussusceptum. Surgeons should know about intussusception as a rare complication of intestinal anisakiasis. Sonography, computed tomography and laparoscopy are helpful in diagnosing and treating this complication.

Transient detection of early wallerian degeneration on diffusion-weighted MRI after an acute cerebrovascular accident

We report three patients with a cerebrovascular accident studied serially by MRI, including diffusion-weighted imaging (DWI). In case 1, DWI 1 day after the onset of left frontoparietal cortical infarcts showed no abnormal signal in the left corticospinal tract. DWI 12 days after onset showed high signal in the corticospinal tract, interpreted as early wallerian degeneration. This had disappeared by 22 days after onset. In case 2, DWI obtained 7 days after the onset of a right internal capsule lacunar infarct showed high signal from the right corticospinal tract in the brainstem, which was less marked 15 days after onset. In case 3, MRI on postnatal day 7 showed a cerebral haemorrhage in the right corona radiata and high signal from the right corticospinal tract on DWI. The latter disappeared by day 23. DWI shows early wallerian degeneration; transient signal abnormalities within 2 weeks of stroke should not be mistaken for new ischaemic lesions.

Formation of advanced tokamak plasmas without the use of an ohmic-heating solenoid

A new operational scenario of advanced tokamak formation was demonstrated in the JT-60U tokamak. This was accomplished by electron cyclotron and lower hybrid waves, neutral beam injection, and the loop voltage supplied by the vertical field and shaping coils. The Ohmic heating (OH) solenoid was not used but a small inboard coil (part of the shaping coil), providing less than 20% of total poloidal flux, was used. The plasma thus obtained had both internal and edge transport barriers, with an energy confinement time of 1.6 times H-mode scaling, a poloidal beta of 3.6, and a normalized beta of 1.6, and a large bootstrap current fraction (>90%). This result opens up a possibility to reduce, and eventually eliminate, the OH solenoid from a tokamak reactor, which will greatly improve its economic competitiveness.

Early scheduled laparoscopic cholecystectomy following percutaneous transhepatic gallbladder drainage for patients with acute cholecystitis

AIM

The present study was conducted to evaluate the effectiveness of early scheduled laparoscopic cholecystectomy (LC) following percutaneous transhepatic gallbladder drainage (PTGBD) for patients with acute cholecystitis.

PATIENTS AND METHODS

31 patients with acute cholecystitis were treated by early scheduled LC following PTGBD (group 1). These patients were compared with 9 patients treated by early LC without PTGBD (group 2) and with 12 patients treated by delayed LC following conservative therapy (group 3) for the success rate of intraoperative cholangiography, the conversion rate to open cholecystectomy, operative time, and hospital stay. Early scheduled LC following PTGBD was defined as scheduled LC when the patient's condition recovered and it was performed 1-7 days (mean: 4 days) after admission. The patients' age in group 1, 2, and 3 was 66 +/- 13, 65 +/- 10, and 64 +/- 9 years, respectively, without significant difference. Most of the patients had additional diseases.

RESULTS

The success rate of intraoperative cholangiography was 97% (30/31) in group 1, 67% (6/9) in group 2, and 67% (8/12) in group 3. The conversion rate to open cholecystectomy was 3% (1/31) in group 1, 33% (3/9) in group 2, and 33% (4/12) in group 3. The operative time for LC was 89 +/- 33 min in group 1, 116 +/- 24 min in group 2, and 135 +/- 30 min in group 3. The mean hospital stay after LC was 9 +/- 4 days in group 1, 9 +/- 3 days in group 2, and 17 +/- 7 days in group 3. In group 1, the success rate of intraoperative cholangiography was higher, the conversion rate to open cholecystectomy was lower, and operative time was shorter than in groups 2 and 3 with significant difference (p <0.05, p <0.05, and p <0.01, respectively).

CONCLUSION

The findings of this study indicate that early scheduled LC following PTGBD is a safe and effective therapeutic option for patients with acute cholecystitis especially in elderly and complicated patients.

Moyamoya disease associated with an anterior inferior cerebellar artery arising from a persistent trigeminal artery

The authors present a case of moyamoya disease associated with a persistent trigeminal artery from which the anterior inferior cerebellar artery arose. We reviewed previously reported cases of moyamoya disease associated with persistent carotid-basilar arterial anastomosis and investigated the embryology of this rare arterial variation.

Extreme fenestration of the right vertebral artery: magnetic resonance angiographic demonstration

The authors describe an extreme fenestration of the right vertebral artery. This anomaly was found incidentally in a female patient undergoing MR imaging and MR angiography evaluation for severe dizziness and headache. Magnetic resonance angiography showed that the right posterior inferior cerebellar artery originated possibly extracranially and anastomosed with the terminal portion of the right vertebral artery, indicating the presence of an extremely large fenestration. This, to our knowledge, is the first report of MR angiographic demonstration of this variation.

Extreme fenestration of the basilar artery associated with cleft palate, nasopharyngeal mature teratoma, and hypophyseal duplication

The authors present the case of a newborn girl with extreme fenestration of the basilar artery. This anomaly was found incidentally during MR imaging study for cleft palate and nasopharyngeal teratoma. Magnetic resonance angiography showed a totally duplicated basilar artery with connections at the proximal and distal ends of the artery, suggesting an extreme fenestration. Duplicated pituitary gland was also found on MR imaging.

Giant Aneurysm of the Cervical Internal Carotid Artery Treated by Proximal Coil Embolization under Temporary Balloon Occlusion

SUMMARY

We report a patient with a giant aneurysm on the left cervical internal carotid artery (ICA) treated successfully by proximal coil occlusion. Fibered platinum coils were delivered via a 5-F catheter under temporary balloon occlusion of the proximal ICA and without complications. MR imaging ten months after the procedure showed the aneurysm to be reduced in size and sub totally thrombosed. Retrograde partial filling of the aneurysmal lumen was present, however. We describe the case in detail and discuss the ideal treatment of the cervical ICA aneurysm.

Laparoscopic appendectomy with the help of a wire snare

This report describes the performance of a laparoscopic appendectomy (LA), a new technique using a "wire snare" without any specific complications. The snare consisted of an 18-gauge injection needle and folded fine wire, measuring 0.28 mm in diameter. LA was performed in 95 patients with acute appendicitis using a cheap and simple wire snare to catch the ligation thread of #0 silk. A good view of the appendix and mesoappendix was obtained in all cases by traction of the #0 silk. The operative time needed to perform LA using a wire snare for nongangrenous appendicitis in 77 cases overall, the first 10 cases, and the last 10 cases was 54+/-17, 64+/-5, and 33+/-4 min, respectively. Two of the 95 patients required conversion to an open appendectomy because of technical difficulties due to the formation of an inflammatory mass. There were no complications associated with insertion of the snare. The wire snare is an innovative technique and does not increase the costs significantly, and should help reduce the number of trocar sites and the operative time, while also making an LA easier to perform.

Supraclinoid carotid dissection in a pediatric patient

The authors present the case of a 13-year-old boy with a left temporal lobe infarction that developed during a 400-m run. Magnetic resonance (MR) angiography showed segmental narrowing of the left supraclinoid internal carotid artery (ICA) and a duplicated left middle cerebral artery (MCA). MR angiographic source images revealed a crescent-shaped left carotid lumen, indicative of a supraclinoid carotid dissection.

Correlation between endoscopic and angiographic findings in patients with esophageal and isolated gastric varices

BACKGROUND/AIM

The correlation between angiographic vascular patterns and endoscopic findings in portal hypertension is not sufficiently known, and knowledge of the vascular anatomy may contribute to an improvement in endoscopic embolization and transjugular retrograde obliteration procedures. We propose a new vascular map that should prove useful for this purpose.

METHODS

Between April 1985 and December 1997 we performed percutaneous transhepatic portography in a selected group of 75 patients (16 women and 59 men), aged 43-71 years, from whom informed consent was obtained. All patients had been diagnosed endoscopically as having either esophageal or isolated gastric varices. According to the Child-Pugh classification, class A, B, and C cirrhosis was seen in 19, 40, and 16 patients, respectively. We created a vascular map of esophageal and isolated gastric varices, based on the opacification of the portal venous collaterals on percutaneous transhepatic portography. We compared the patients in both variceal groups in terms of portal venous pressure, main blood supply, and drainage routes.

RESULTS

We found that the portal collateral system was divided into two systems: the portoazygos venous system and the portophrenic venous system. The former contributed to the formation of esophageal and cardiac varices and the latter to the formation of isolated gastric varices located at the fundus or at both the cardia and fundus. The left gastric vein participated as blood supply in 70% of the isolated gastric varices and in 100% of the esophageal varices (p < 0.01). The posterior gastric vein participated as blood supply in 70% of the isolated gastric varices and in 24% of the esophageal varices (p < 0.01). We classified the main blood drainage routes of isolated gastric varices functionally into three types: gastrorenal shunt (85%), gastrophrenic shunt (10%), and gastropericardiac shunt (5%). The portal venous pressure in patients with esophageal varices was 358 +/- 66 mm H(2)O, whereas in patients with isolated gastric varices it was 262 +/- 44 mm H(2)O (p < 0.01).

CONCLUSION

We suggest that this new vascular map will be useful in endoscopic embolization and transjugular retrograde obliteration procedures for esophageal and isolated gastric varices.

Persistent primitive olfactory artery: diagnosis with MR angiography

We present a case of persistent primitive olfactory artery (PPOA) diagnosed with the aid of magnetic resonance (MR) angiography. The proximal right anterior cerebral artery (ACA) had an extremely long anteroinferomedial course along the ipsilateral olfactory tract, made a hairpin turn posterosuperiorly, and became a normal distal ACA. After reviewing the literature, we considered the proximal segment of this anomalous ACA to be a PPOA. To our knowledge, this is the first report of a patient with this anomalous ACA diagnosed with MR angiography.

Persistent trigeminal artery variants detected by MR angiography

Persistent trigeminal artery (PTA) variants are cerebellar arteries that originate directly from the precavernous portion of the internal carotid artery (ICA). The goal of our study was to determine the incidence and MR angiographic features of PTA variants. Between April 1996 and September 1999, 523 cranial MR angiographies were performed at our institution. Most of the patients examined had or were suspected of having cerebrovascular disease. We retrospectively reviewed these 523 MR angiograms. A 1.5-T scanner was used in all studies, and maximum intensity projection (MIP) images obtained using the three-dimensional time-of-flight (3D TOF) technique were displayed stereoscopically. Four PTA variants were detected on MR angiograms, at a rate of 0.76%. At least three of the four PTA variants were anterior inferior cerebellar arteries (AICAs), small tortuous arteries arising from the precavernous portions of the ICAs and taking a posterior course. Although the clinical significance is not great, we found a relatively high incidence of PTA variants on MR angiograms. We stress that knowledge and recognition of these anomalous cerebellar arteries are useful and important in the interpretation of cranial MR angiograms.

The biosynthesis of broussonetines: origin of the carbon skeleton

Broussonetines are glycosidase-inhibitory alkaloids obtained from Broussonetia kazinoki. Feeding experiments using [1-13C]glucose and 13C-NMR spectroscopic studies showed that broussonetines are biosynthesized through routes similar to those of sphingosine and phytosphingosine.