RF generation using a compact bench gyromagnetic line.

The search for new technologies aiming to reach radiofrequency (RF) generation in different manners for diverse ends is a constant demand for several applications. The goal is to develop cost-effective and simpler systems compared to those that already exist. Our motivation is to reach an alternative way of generating RF in pulsed transmission systems employing a gyromagnetic nonlinear transmission line (GNLTL). The GNLTL consists of a ferrite-loaded-coaxial transmission line and can produce a large frequency spectrum with RF conversion efficiency above 10% from about 200 MHz up to the frequency of 2-4 GHz (S-band) for potential space-based applications. In a GNLTL, the signal amplitude is related to its propagation velocity since the peak voltage travels faster than its portion of lower amplitudes since the ferrite permeability decreases with the current amplitude. As the pulse crest travels faster than its valley, a time reduction happens in the output rise time, called pulse sharpening. Besides, the magnetic moments of ferrite dipoles initially aligned with the axial magnetic bias are displaced from their original position by the azimuthal field generated around the inner conductor by the current pulse, resulting in a damped precession movement. This movement happens along the line length as the current pulse propagates, inducing high-frequency oscillations. In short, the paper's goal is to present the experimental results using a 60-cm gyromagnetic line to provide RF in the GHz range using a solenoid for magnetic bias on a testing bench. Finally, the paper discusses the influence of the azimuthal and the axial magnetic fields on the output signal with the ferrite rings operating in a saturation state during the current pulse propagation.

Minimal deviation endometrioid adenocarcinoma of the endometrium and its MRI findings.

Minimal deviation endometrioid adenocarcinoma (MDA-E) of the endometrium is a rare pathological entity, and its radiological features are rarely documented. A 73-year-old Japanese woman was referred to the authors when an endometrial biopsy revealed moderately differentiated endometrioid adenocarcinoma. Preoperative radiological examinations, including ultrasound, computed tomography (CT), and magnetic resonance imaging (MRI) showed no evidence of cancer nests. In the hysterectomy specimen, mildly atypical glands were scattered throughout the entire depth of the myometrium, without stromal desmoplastic reaction, and a tiny focus of typical, ruptured, endometrioid adenocarcinoma glands was found in the atrophic endometrium. MRI had not been able to identify this unusual, scattered, myometrial invasion. It should be kept in mind that in cases showing Stage IA endometrial carcinoma without endometrial thickening on MRI, this rare form of invasion may be present.

The effect of donepezil treatment on cardiovascular mortality.

The acetylcholinesterase inhibitor donepezil hydrochloride improves cognitive function in patients with Alzheimer's disease and vascular dementia. Given acetylcholine's important actions on the heart, we undertook a retrospective cohort investigation to assess whether donepezil usage affects cardiovascular mortality. In patients treated with donepezil, hazard ratios for total and cardiovascular mortality were 0.68 (P = 0.045, 95% confidence interval 0.46-0.99) and 0.54 (P = 0.042, 95% confidence interval 0.30-0.98), respectively. The apparent survival benefit in donepezil-treated patients should not be overinterpreted. Prospective clinical trials are warranted.

Bleeding time prolonged by daily low-dose aspirin is shortened by one medium dose aspirin.

BACKGROUND: In planning surgery, a low-dose aspirin regimen for prevention of thrombotic events is often discontinued in order to avoid the risk of excessive bleeding during surgery. However, this procedure increases the risk from adverse thrombotic events. We propose a different method, which may normalize the prolonged bleeding time caused by low-dose aspirin. We verified the effectiveness of this method in healthy volunteers. METHODS: Volunteers with bleeding time prolonged by taking 81 mg of aspirin a day for a period of 1 week were randomly divided into two groups. The test group of 18 volunteers received a dose of 660 mg of aspirin, while the control group of 16 received placebo. Bleeding time and maximum platelet activity were then evaluated. RESULTS: Before 660 mg of aspirin or placebo, bleeding time was prolonged: in the aspirin group from 3.1 +/- 0.7 to 6.1 +/- 1.4 min (n=18), and in the placebo group from 2.9 +/- 0.9 to 6.1 +/- 1.5 min (n=16). This prolongation was significant in both groups at the P<0.01 level. In the test group, bleeding time was shortened to 4.5 +/- 1.3 min (P<0.01), which is in the normal range, while it remained prolonged in the control group (6.0 +/- 1.2 min). Platelet activity, on the other hand, was suppressed in both groups. CONCLUSION: We conclude that 660 mg of aspirin effectively shortens the bleeding time prolonged by daily low-dose (81 mg) aspirin.

Centrosome amplification induced by survivin suppression enhances both chromosome instability and radiosensitivity in glioma cells.

Glioblastoma is characterised by invasive growth and a high degree of radioresistance. Survivin, a regulator of chromosome segregation, is highly expressed and known to induce radioresistance in human gliomas. In this study, we examined the effect of survivin suppression on radiosensitivity in malignant glioma cells, while focusing on centrosome aberration and chromosome instability (CIN). We suppressed survivin by small interfering RNA transfection, and examined the radiosensitivity using a clonogenic assay and a trypan blue exclusion assay in U251MG (p53 mutant) and D54MG (p53 wild type) cells. To assess the CIN status, we determined the number of centrosomes using an immunofluorescence analysis, and the centromeric copy number by fluorescence in situ hybridisation. As a result, the radiosensitisation differed regarding the p53 status as U251MG cells quickly developed extreme centrosome amplification (=CIN) and enhanced the radiosensitivity, while centrosome amplification and radiosensitivity increased more gradually in D54MG cells. TUNEL assay showed that survivin inhibition did not lead to apoptosis after irradiation. This cell death was accompanied by an increased degree of aneuploidy, suggesting mitotic cell death. Therefore, survivin inhibition may be an attractive therapeutic target to overcome the radioresistance while, in addition, proper attention to CIN (centrosome number) is considered important for improving radiosensitivity in human glioma.

Epidural puncture can be confirmed by the Queckenstedt-test procedure in patients with cervical spinal canal stenosis.

BACKGROUND: The loss-of-resistance test is the most popular method for identifying the epidural space, but it cannot confirm epidural puncture. Therefore, we developed a new method to confirm epidural puncture by assessing indirect changes in epidural pressure using the Queckenstedt-test procedure, which increases subarachnoid pressure by compressing the internal jugular veins. Because this new method depends on the dynamics of cerebrospinal fluid, blockade of cerebrospinal fluid flow, as with severe spinal stenosis, is predicted to reduce changes in epidural pressure. Thus, in this study, we examined the effect of spinal stenosis on the Queckenstedt-test procedure. METHODS: Epidural puncture using the loss-of-resistance test was utilized to insert an electrode in patients undergoing cervical spine surgery. Epidural pressure was monitored during bilateral compression of the internal jugular veins to confirm epidural puncture. The insertion of the electrode into the epidural space was confirmed by observation of muscle twitch evoked by electric stimulation. RESULTS: In 60 patients, epidural puncture was performed with the loss-of-resistance test; a second trial was required in 13 patients. Increased epidural pressure was observed in 57/73 trials. When increased epidural pressure was observed, epidural puncture was always successful. The sensitivity and specificity of this method was 92.0% and 100%, respectively. The positive and negative predictive values were 100% and 66.7%, respectively. CONCLUSION: An increase in epidural pressure during bilateral compression of the internal jugular veins could offer a reliable method for confirming epidural puncture in combination with the loss-of-resistance test, even if patients have potential spinal canal narrowing.

The characteristics and failure pattern of gefitinib responders with postoperative recurrence of pulmonary adenocarcinoma.

AIMS: Gefitinib shows prominent anti-tumor activity against advanced or recurrent non-small cell lung cancer (NSCLC). However, most gefitinib-responsive patients ultimately relapse. We reviewed postoperatively recurrent NSCLC patients who received gefitinib treatment, and analyzed both the clinical features and manifestations of treatment failure in patients who initially responded to gefitinib. METHODS: From 2002 to 2006, gefitinib was administered to in 34 postoperative recurrent lung adenocarcinoma patients. There were 13 men and 21 women with a mean age of 65 years. Twenty patients had never smoked while 14 were former smokers. Epidermal growth factor receptor (EGFR) gene mutation was measured using surgical specimens of the primary tumor. RESULTS: The study group showed 1 complete response, 16 partial responses, 7 stable diseases and 8 progressive diseases. Mutations of EGFR gene were detected in 20 of 34 patients. Only the presence of EGFR gene mutations was significantly associated with the clinical response of gefitinib in our limited study (p=0.036). In 9 of 12 responders, gefitinib treatment failed due to the appearance of new lesions. CONCLUSIONS: Gefitinib was significantly effective for patients with mutations of the EGFR gene and most responders failed due to the appearance of new lesions without progression of the pre-existent target lesions.

Reduction of radiation-induced apoptosis by specific expression of Bcl-2 in normal cells.

Radiation-induced apoptosis is thought to underlie the toxicity of radiation to normal tissues as well as to cancer cells. We hypothesized that specific ectopic overexpression of the antiapoptotic molecule Bcl-2 in normal cells would inhibit radiation-induced apoptosis and thereby reduce radiation-induced toxicity in normal cells. To express Bcl-2 specifically in normal cells (which have wild-type (wt) p53) but not in cancer cells (which often have mutated p53), we constructed a Bcl-2 expression plasmid (PG13-Bcl-2) with a minimal promoter regulated by multiple wt p53 DNA-binding sites and found that the presence of wt p53 protein strongly upregulated Bcl-2 expression through this plasmid. Transfection of NIH 3T3 fibroblasts, which express wt p53, with PG13-Bcl-2 increased cell survival and reduced apoptosis; however, transfection of MDA-MB-231 breast cancer cells, which have mutated p53, did not affect survival and apoptosis of those cells. These results indicate that irradiation of normal cells rapidly upregulates the expression of wt p53, which binds to the p53 binding sequence of the PG13-Bcl-2 plasmid and increases the transcriptional activity of Bcl-2. Ectopic expression of Bcl-2 reduced radiation-induced apoptosis only in normal cells (not in cancer cells). Bcl-2 expression was detected in the lung from mice injected via a tail vein with LPD-PG13-Bcl-2 or LPD-CMV-Bcl-2, but did not in the lung from mice treated with DOTAP or LPD-PG13-mock. This novel approach to inhibiting radiation-induced apoptosis in normal cells may allow such cells to be protected from radiation-induced toxicity. Further preclinical in vivo studies are needed.

Association between arterial stiffness and platelet activation.

Increased arterial stiffness is strongly associated with atherosclerosis, while platelet activation is an important trigger of thrombotic events in patients with atherosclerosis. However, little is known about the effect of arterial stiffness on platelet activation. We therefore investigated the association between arterial stiffness and platelet activation in 38 normal volunteers (20 men and 18 women) aged 23-77 years (mean = 49 +/- 15 years). Arterial stiffness was assessed by measuring brachial-ankle pulse wave velocity (ba-PWV) and heart-brachial PWV (hb-PWV). Flow cytometric analyses were performed to evaluate platelet activation by measuring surface expression of P-selectin and platelet-neutrophil complexes (PNC) before and after activation by ADP. We also calculated the difference between basal and stimulated states of P-selectin and PNC to assess platelet activation reserve. PWVs were significantly correlated with age and BP (r = 0.60-0.81). For platelet activation and activation reserve, correlations with age were less strong but remained significant (r = 0.36-0.61), with the exception of P-selectin (not significant, NS), and correlations with SBP were similar (r = 0.35-0.53). A significant correlation was found between PWVs and platelet activation (r = 0.43-0.74). Multiple regression analysis demonstrated significant correlations between platelet activation and reserve and PWVs (coefficient = 2.17-6.59), when both age and BP were adjusted for simultaneously. In conclusion, platelet activation was associated with arterial stiffness, suggesting that arterial stiffness may play an important role in thrombotic events.

p16 Gene transfer increases cell killing with abnormal nucleation after ionising radiation in glioma cells.

It is well established that cells synchronised at the G1-S phase are highly radiosensitive. In this study, p16-null human glioma cell lines were induced into G1 cell cycle arrest by adenovirus-mediated p16 gene transfer, and examined for radiation-induced cell killing. Clonogenic analysis and trypan blue extraction test showed that the p16 gene transfer enhanced radiation-induced cell killing in p16-null glioma cell lines. TUNEL assays and pulse-field gel electrophoresis confirmed that the radiation-induced cell killing of p16-transfected cells could be caused by a nonapoptotic mechanism. Gimsa staining demonstrated that irradiation alone or Ax-mock infection plus irradiation results in a slight increase in the frequency of cells with abnormal nucleus, compared to unirradiated uninfected or Ax-mock infected cells. However, Ax-hp16 or Ax-hp21 infection alone modestly increased the frequency of cells with abnormal nucleus (especially bi- and multinucleation), and 4-Gy irradiation of Ax-hp16 or Ax-hp21 infected cells substantially enhanced this frequency. These results suggest that there exists some unknown interaction between radiation and p16 in cytoplasm/membranes, which decreases cytokinesis and promotes abnormal nucleation. Thus, p16 expression prevented radiation-induced apoptosis by promoting abnormal nucleation, thereby leading to another mode of cell death.

Detection of a pineoblastoma with large central cyst in a young child.

THE PATIENT: We present the very rare case of a pineoblastoma with large central cyst in a 7-year-old boy who presented with a short history of gradually worsening headache and upward gaze palsy. IMAGING INVESTIGATIONS: On CT and MRI studies, it was seen as a peripherally calcified, irregularly shaped mass with heterogeneous low signal intensity on T1-weighted images and ringed enhancement after gadolinium administration; there was homogeneous high signal intensity on T1-weighted images. DISCUSSION: We discuss differential diagnosis for several types of cystic tumors in the pineal region, including pineoblastomas.

[A case of juvenile pilocytic astrocytoma with unusual neuroimaging features].

We present a case of cerebellar juvenile pilocytic astrocytoma(JPA) with unusual neuroimaging features. The patient was a 14-year-old male who suffered from chronic headaches for a couple of weeks. Plain craniogram showed a decalcification and bulging of the occipital bone. Computed tomography(CT) scans demonstrated low density multiple components with small calcifications in the right cerebellar hemisphere extending to the left. These calcifications were found at the margin of these multi-lobular components. Magnetic resonance imaging(MRI) revealed iso or low intensity on T1 weighted image, and slightly high intensity on T2 weighted image. The lesion indicated more heterogeneous and higher intensity than brain parenchyma on FLAIR imaging, and remarkable higher intensity than brain parenchyma with some small low intensity areas on diffusion weighted imaging. He underwent the complete resection except for the cranial tissue surrounding the pons. Histologic diagnosis was juvenile pilocytic astrocytoma, because of biphasic pattern of bipolar cells and a number of Rosenthal fibers. Generally JPA has sharp and smooth demarcated cysts with well-enhanced mural nodule. It was difficult to diagnose the presented tumor as JPA before operation, since its unusual neuroimaging resembled both dermoid and high grade gliomas.

[A case of convexity meningioma en plaque].

We present a case of convexity meningioma en plaque (MEP). A 51-year-old male occasionally suffering from right parietalgia and numbness of left upper limb. An intracranial abnormal mass was pointed out incidentally by the brain check up. Computed tomographic (CT) scans demonstrated a hyperostosis and an enhanced abnormal mass at the right front-parietal region. Magnetic resonant images (MRI) revealed a carpet like tumor extended along the dura mater. Cerebral angiography disclosed feedings from parietal branches of right middle meningeal artery and superficial temporal artery. The tumor was removed subtotally with adjacent dura mater, leaving the portion of close adhesion to the brain parenchyma. Histologic diagnosis was transitional meningioma. Immunohistological stainings showed a high staining index (6.9%) of MIB-1 (Ki-69 antigen) and high expression of metalloproteinase-9 (MMP-9), especially along the dura mater. Convexity MEP is so rare that we review previous reported cases of convexity MEP, and discuss the clinicopathologic features on that.

Intrasellar rhabdomyosarcoma: case report.

OBJECTIVE AND IMPORTANCE: There has been only one reported case of an intrasellar rhabdomyosarcoma, the origin of which was in the para-nasal sinus. The authors encountered a patient with an intrasellar rhabdomyosarcoma with no evidence of tumor at any additional sites. CLINICAL PRESENTATION: A 28-year-old otherwise healthy man complaining of headache exhibited left abducent nerve palsy and left visual disturbance. The patient was diagnosed as having a sellar tumor invading the left cavernous sinus. INTERVENTION: Near total removal of the tumor was achieved via a trans-sphenoidal approach. Histologically, the tumor was composed of small, round-to-elongated undifferentiated cells and large spindle cells with myoblastic features. Immunohistochemically, tumor cells were positive for antibodies against desmin, myoglobin, and alpha-smooth muscle actin. The tumor was identified as an embryonal rhabdomyosarcoma on the basis of the above pathological findings. Systemic investigation, including the nasal and para-nasal regions, failed to detect any additional tumors. Postoperative local radiation therapy and chemotherapy with the use of ifosfamide, etoposide, and vincristine brought about complete initial remission. CONCLUSION: Rhabdomyosarcoma should be considered in the differential diagnosis of a primary intrasellar neoplasm.

Morphologic features of human chorionic gonadotropin- or alpha-fetoprotein-producing germ cell tumors of the central nervous system: histological heterogeneity and surgical meaning.

Our study of germ cell tumors (GCT) of the central nervous system (CNS) investigated the relationship between tumor histology and patient serum titers of human chorionic gonadotropin (HGC) and alpha-fetoprotein (AFP). Thirty-five patients were enrolled. Their serum titers of HCG (mlU/ml) and/or AFP (ng/ml) before initial treatment were available, as were tumor specimens obtained before the administration of adjuvant therapy. They were divided into three groups, depending on whether HCG alone (group H), AFP alone (group A), or both HCG and AFP (group HA) were detected. Each group was subdivided into three groups: patients in group I had H, A, and/or HA titers below 9.9; patients in group II/III had titers from 10.0 to 999; and those in group IV had titers of 1000 or more. Serial sections of tissue specimens were repeatedly stained, mainly with hematoxylin and eosin (H-E) stain, HCG immunostain, and AFP immunostain. There were seven patients in the H-I group and five in H-II/III. Of these 12 patients, 11 had germinomas (G) and one had an embryonal carcinoma (EC). Five patients were included in group A: one was classified as A-II/III and had a germinoma, and the remaining four patients were in A-IV and had yolk sac tumors (YST) or mixed GCT consisting mainly of YST or EC (MXGCT-YST, EC). The HA group consisted of 18 patients. Three were classified as HA-I and had germinomas; nine HA-II/III patients had T or MXGCT-T; and six HA-IV patients had choriocarcinoma (CC), YST, MXGCT-CC, or MXGCT-YST. Throughout the study, the situations for the elevated serum titers could be elucidated in only four cases (three in group A-IV and one in group HA-IV). These results led to the conclusion that serologic evaluation is superior to morphologic evaluation in diagnosing marker-producing GCTs. From a diagnostic perspective, the role of surgery is to verify the HCG- and AFP-immunonegative tissue in patients with G, T, and EC.

[Symptomatic subependymoma of the lateral ventricle in a young female].

We present a case of a symptomatic subependymoma (SE) in a young. The patient was a 20-year-old female who suffered from severe headache and vomiting. Precontrast CT scans revealed a large spotty-calcified isodensity mass lesion in the right anterior lateral ventricle, showing scarce contrast enhancement at the center of the mass and with marked hydrocephalus. MRI demonstrated the lesion as slightly hypo-intensity on T1-weighted image, hyper-intensity on T2-weighted image. On FLAIR imaging, the lesion indicated remarkable hyperintensity and was clearly distinguishable from surrounding brain parenchyma and the cerebrospinal fluid. After Gd-DTPA infusion central vein was revealed, but no tumor enhancement was seen. The tumor was totally extirpated through the transcortical approach. Histological diagnosis was SE, and high MIB-1 staining index (9.3%) was seen. FLAIR imaging is useful for the preoperative diagnosis and the postoperative assessment of SEs.

Correlates of bundle-branch block in patients undergoing primary angioplasty for acute myocardial infarction.

BACKGROUND: Early reperfusion therapy has reduced the infarct size and mortality rate in patients with acute myocardial infarction (AMI). The occurrence of bundle-branch block in AMI is related to the amount of myocardial damage and the insult to the conduction system. HYPOTHESIS: To evaluate the clinical and angiographic factors related to the occurrence of bundle-branch block (BBB) in patients with primary percutaneous transluminal coronary angioplasty (PTCA), we investigated consecutive series of patients with their first Q-wave AMI and successful PTCA. METHODS: Coronary angiogram at the time of admission, electrocardiogram, and echocardiogram were evaluated in 279 patients with their first Q-wave AMI and successful PTCA. RESULTS: Bundle-branch block was detected in 26 patients (9%); 16 patients had transient and 10 patients had persistent block, while 16 patients had bifascicular block and 10 patients had right BBB. The patients with BBB had a significantly larger number of left ventricular asynergic segments, higher incidence of total occlusion of infarct-related artery, angiographic no reflow, and pericardial rub than those without BBB. When the multivariate analysis was performed using five clinical markers of infarct severity, angiographic no reflow (F = 20.2, p < 0.001) and total occlusion of infarct-re-lated artery (F = 4.2, p = 0.04) were found to be the significant variables related to BBB. CONCLUSIONS: Despite successful primary PTCA, absence of antegrade flow in the infarct-related artery at the onset of AMI and/or angiographic no reflow resulted in more severe transmural myocardial damage and, hence, the occurrence of BBB.

Recurrence of meningiomas.

BACKGROUND: Macroscopic total resection with removal of involved dura and bone does not always prevent the recurrence of meningioma of histologically benign subtype. Many causative factors have been investigated, although the mechanism of recurrence remains unclear. Vascular endothelial growth factor (VEGF) is a key factor in meningiomas neovascularization, and the authors investigated whether VEGF expression can predict the recurrence of histologically benign meningiomas after macroscopic total resection. METHODS: Fifty-four patients with supratentorial convexity meningiomas were investigated at least 3 years after surgery or until tumor recurrence to clarify risk factors for recurrence. Patients were restricted to Simpson Grade 1 resection only, and the authors excluded multiple meningiomas, neurofibromatosis, and atypical and anaplastic meningiomas. Correlation between recurrence and the following factors were statistically analyzed: age, gender, tumor volume, tumor shape, bone change, brain edema, vascular supply, histologic subtype, MIB-1 labeling index (LI), and VEGF expression. RESULTS: Of the 54 patients with meningioma, 34 were positive (24: +1; 10: +2) for VEGF, and 20 were negative. Six (11.1%) meningiomas recurred during the follow-up period. Multivariate analysis revealed that high levels of expression of VEGF constituted the most useful predictor of recurrence (P = 0.005), followed by high MIB-1 LI (P = 0.039). The other factors were not significant. The tumor recurrence, when it occurred, was within the brain and not durally based. CONCLUSIONS: The current results suggest that high levels of VEGF expression are significantly related to the recurrence of meningioma. VEGF secretion from microscopic residue remaining after surgery may induce neovascularization, which promotes the recurrence of meningioma.