Metal Artifact Reduction in Head CT Performed for Patients with Deep Brain Stimulation Devices: Effectiveness of a Single-Energy Metal Artifact Reduction Algorithm.

BACKGROUND AND PURPOSE: Deep brain stimulation electrodes induce massive artifacts on CT images, deteriorating the diagnostic value of examinations. We aimed to investigate the usefulness and potential limitations of a single-energy metal artifact reduction algorithm in head CT performed in patients with implanted deep brain stimulation devices. MATERIALS AND METHODS: Thirty-four patients with deep brain stimulation (bilateral, n = 28) who underwent head CT on a 320-detector row scanner and whose images were reconstructed with and without single-energy metal artifact reduction at the examinations were retrospectively included. The severity of artifacts around electrodes was assessed objectively using SDs and an artifact index. Two radiologists subjectively evaluated the severity of artifacts from electrodes, the visibility of electrode localization and surrounding structures, and overall diagnostic confidence on 4-point scales. Background image quality (GM-WM contrast and image noise) was subjectively and objectively assessed. The presence and location of artifacts newly produced by single-energy metal artifact reduction were analyzed. RESULTS: Single-energy metal artifact reduction provided lower objective and subjective metal artifacts and improved visualization of electrode localization and surrounding structures and diagnostic confidence compared with non-single-energy metal artifact reduction images, with statistical significance (all, P < .01). No significant differences were observed in GM-WM contrast and image noise (all, P ≥ .11). The new artifacts from single-energy metal artifact reduction were prominently observed in patients with bilateral deep brain stimulation at high convexity, possibly induced by deep brain stimulation leads placed under the parietal scalp. CONCLUSIONS: Single-energy metal artifact reduction substantially reduces the metal artifacts from deep brain stimulation electrodes and improves the visibility of intracranial structures without affecting background image quality. However, non-single-energy metal artifact reduction images should be simultaneously reviewed to accurately assess the entire intracranial area, particularly in patients with bilateral deep brain stimulation.

DUSP22/LMW-DSP2 regulates estrogen receptor-alpha-mediated signaling through dephosphorylation of Ser-118.

In the previous study, we demonstrated the involvement of dual specificity phosphatase 22 (DUSP22/LMW-DSP2) in regulating the leukemia inhibitory factor/interleukin-6/signal transducer and activator of transcription 3-mediated signaling pathway. In this study, we show beta-estradiol (E2)-induced DUSP22 mRNA expression in estrogen receptor alpha (ERalpha)-positive breast cancer cells, whereas E2-induced phosphorylation and activation of ERalpha was suppressed by overexpression of DUSP22 but not catalytically inactive mutants. Furthermore, small-interfering RNA-mediated reduction of DUSP22 expression enhanced ERalpha-mediated transcription and endogenous gene expression. In fact, DUSP22 associated with ERalpha in vivo and both endogenous proteins interacted in ERalpha-positive breast cancer T47D cells. These results strongly suggest that DUSP22 acts as a negative regulator of the ERalpha-mediated signaling pathway.

Cigarette smoking and the haemodynamic response to tracheal intubation.

This study investigated the effects of smoking and gender on the haemodynamic response after tracheal intubation. Patients were assigned to one of four groups: female non-smokers, female smokers, male non-smokers and male smokers. After tracheal intubation, the highest mean (SD) increase in heart rate (30 (18) %) and rate-pressure product (40 (29) %) was seen in male smokers. The increases in heart rate and rate-pressure product in male smokers were significantly greater than those in female non-smokers, p < 0.05. The increase in rate-pressure product was significantly greater in male smokers than in male non-smokers, p = 0.022.

Regulation of STAT3-mediated signaling by LMW-DSP2.

Signal transducer and activator of transcription 3 (STAT3), which mediates biological actions in many physiological processes, is activated by cytokines and growth factors, and has been reported to be constitutively activated in numerous cancer cells. In this study, we examined whether low molecular weight-dual specificity phosphatase two (LMW-DSP2) is involved in the regulation of the interleukin 6 (IL-6)/leukemia inhibitory factor (LIF)/STAT3-mediated signaling pathway. IL-6/LIF-induced LMW-DSP2 expression in murine testicular or hepatoma cell lines, while LMW-DSP2 overexpression in 293T cells suppressed IL-6-induced phosphorylation and activation of STAT3. Furthermore, LMW-DSP2 suppressed the expression of IL-6-induced endogenous genes. In contrast, small-interfering RNA-mediated reduction of LMW-DSP2 expression enhanced IL-6-induced STAT3-dependent transcription. In fact, LMW-DSP2 interacted with STAT3 in vivo and endogenous LMW-DSP2 bound to STAT3 in murine testicular GC-1 cells. These results strongly suggest that LMW-DSP2 acts as a negative regulator of the IL-6/LIF/STAT3-mediated signaling pathway.

Constitutive IL-8 expression in cancer cells is associated with mutation of p53.

We previously reported that most cancer cell lines constitutively express various cytokines including IL-8. But how IL-8 gene expression is regulated in cancer cells is still unclear. p53 tumor suppressor gene plays an important role in the regulation of transcription and is mutated in cancer cell lines. We investigated whether p53 status affects the constitutive expression of IL-8 in human cancer cells. SUIT-2 and RERF-LCOK cancer cells constitutively produced high levels of IL-8 in culture medium. Both cell lines were shown to carry a p53 mutation, and constitutive NF-kappaB transcriptional activity. To analyze whether p53 status mediates IL-8 expression, the effect of wild-type p53 (wt-p53) gene transfer on activation of NF-kappaB was determined in both cell lines. ELISA showed that the IL-8 concentration in medium decreased dose dependently by transient expression of wt-p53. Western-blot analysis showed no marked change in NF-kappaB protein levels in cell nuclei. EMSA showed no repression of NF-kappaB binding activity after transient expression of wt-p53. In contrast, luciferase reporter studies indicated that transcriptional activity of NF-kappaB is suppressed by transfection of wt-p53. These results show that wt-p53 gene transfer inhibits IL-8 production and NF-kappaB transcription activity in cancer cells and suggest that constitutive IL-8 production in cancer cells is associated with mutation of p53.

Hyperintensities of the optic radiation on T2-weighted MR images of elderly subjects.

BACKGROUND AND PURPOSE: Although abnormal hyperintensities are frequently observed at or around the optic radiation in elderly subjects, no previous reports have mentioned the clinical significance and pathologic changes of these hyperintensities. We evaluated the hyperintensity patterns of the optic radiation and its surrounding structures on T2-weighted MR images and compared these findings with pathologic observations and visual field measurements. METHODS: High-resolution coronal T2-weighted MR images of 102 consecutive patients (51-84 years old) were evaluated retrospectively for the presence and morphology of hyperintensities of the optic radiation (204 sides) and its surrounding structures. Pathologic specimens were obtained from 25 other patients (60-91 years old) who had died of nonneurologic causes. The histopathologic changes of the optic radiation and its surrounding structures were evaluated and correlated with the MR findings. Finally, MR findings and visual field measurements were correlated in 46 elderly volunteers (70-91 years old). RESULTS: Hyperintensities of the optic radiation or its surrounding structures or both were observed on 125 sides (93%) of 67 patients (61%), and linear/laminar hyperintensity of the optic radiation and the tapetum was the characteristic finding. Eleven (44%) of 25 pathologic specimens exhibited pallor of three anatomic layers (the external sagittal stratum or the optic radiation, the internal sagittal stratum, and the tapetum). No subjects with hyperintensity of the optic radiation had visual field abnormalities. CONCLUSION: Linear/laminar hyperintensity of the optic radiation and tapetum on T2-weighted images is common in elderly subjects, and may reflect differences in the internal structures and in the water content of three anatomic structures. Hyperintensities of this region did not cause visual field abnormalities in a group of elderly volunteers.

Gd-enhanced dynamic magnetic resonance imaging of breast masses.

The combination of morphologic and hemodynamic analyses of contrast-enhanced dynamic magnetic resonance imaging is valuable for characterizing breast masses. Pharmacokinetic parameters such as k and f reflect histologic architecture of breast masses. We believe that MR imaging may be of value for diagnosis of breast masses.

STAP-2 interacts with and modulates BCR-ABL-mediated tumorigenesis.

In chronic myeloid leukemia (CML), the BCR-ABL fusion oncoprotein activates multiple pathways involved in cell survival, growth promotion and disease progression. In this report, we show that the signal-transducing adaptor protein-2 (STAP-2) is involved in BCR-ABL activity. We demonstrate that STAP-2 bound to BCR-ABL, and BCR and ABL proteins, depending on the STAP-2 Src homology 2-like domain. BCR-ABL phosphorylates STAP-2 Tyr250 and the phosphorylated STAP-2 in turn upregulated BCR-ABL phosphorylation, leading to enhanced activation of downstream signaling molecules including ERK (extracellular-signal-regulated kinase), STAT5 (signal transducer and activator of transcription 5), BCL-xL (B-cell lymphoma-extra large) and BCL-2(B-cell lymphoma 2). In addition, STAP-2 interacts with BCR-ABL to alter chemokine receptor expression leading to downregulation of CXCR4 and upregulation of CCR7. The interaction between STAP-2 and BCR-ABL plays a crucial role in conferring a growth advantage and resistance to imatinib, a BCR-ABL inhibitor, as well as tumor progression. Notably, mice injected with BCR-ABL/STAP-2-expressing Ba/F3 cells developed lymph node enlargement and hepatosplenomegaly. Moreover, suppression of STAP-2 in K562 CML cells resulted in no tumor formation in mice. Our results demonstrate a critical contribution of STAP-2 in BCR-ABL activity, and suggest that STAP-2 might be an important candidate for drug development for patients with CML. Furthermore, the expression of STAP-2 provides useful information for estimating the characteristics of individual CML clones.

Physical and functional interactions between STAT3 and KAP1.

Signal transducers and activators of transcription (STATs) mediate cell proliferation, differentiation and survival in immune responses, hematopoiesis, neurogenesis and other biological processes. For example, STAT3 has been reported to be constitutively activated in numerous cancer cells. To clarify the molecular mechanisms underlying the STAT activation, we performed yeast two-hybrid screening and identified KAP1/TIF1beta as a novel STAT-binding partner. KAP1 is a universal corepressor protein for the Kruppel-associated box zinc-finger protein superfamily of transcriptional repressors. We found endogenous KAP1 associated with endogenous STAT3 in vivo. Importantly, small-interfering RNA-mediated reduction of KAP1 expression enhanced interleukin (IL)-6-induced STAT3-dependent transcription and gene expression. Furthermore, reduction of KAP1 expression resulted in the marked accumulation of STAT3 phosphorylated on Ser727 in the nucleus, a modification that regulates its transcriptional activation. These results indicate that KAP1 may serve as a transcriptional regulator of the IL-6/STAT3 signaling pathway.

Acute adrenal hemorrhage after blunt trauma.

OBJECTIVE: To determine the appropriate management of adrenal hemorrhage in patients with severe chest and upper abdominal blunt trauma. MATERIALS AND METHODS: We reviewed 7 patients who suffered from severe traumatic adrenal hemorrhage after a traffic accident (n = 4) or fall (n = 3). Contrast-enhanced CT images were analyzed for multi-organ traumatic injury, hematoma size, extravasation, and pseudoaneurysm formation. We also report their management including transarterial embolization (TAE) and follow-up findings. RESULTS: All 7 patients manifested multi-organ traumatic injury and hemothorax; 5 also had rib fractures, 5 had abdominal organ injuries (liver, n = 3; kidneys, n = 2; pancreas, n = 1); 2 had dorsal fractures, and 1 had a traumatic aortic aneurysm. On CT images, unilateral right adrenal hematomas ranging from 20 to 50 mm (mean 26 mm) in length and from 15 to 50 mm (mean 23 mm) in width were seen. In 6 patients these were localized, and they were followed without any intervention. The other patient had a massive hematoma with pseudoaneurysm and extravasation, who subsequently received TAE. At 3-month follow-up all patients were doing well. CONCLUSION: Information regarding the size of the hematoma and the presence of extravasation helps to select the appropriate management of patients with traumatic adrenal hemorrhage. TAE appears to be useful for treating patients with massive adrenal hemorrhage.

Evaluation of the efficacy of combined continuous arterial infusion and systemic chemotherapy for the treatment of advanced pancreatic carcinoma.

PURPOSE: To evaluate the effects of combined continuous transcatheter arterial infusion (CTAI) and systemic chemotherapy in patients with advanced pancreatic carcinoma. METHODS: CTAI was performed in 17 patients with stage IV pancreatic cancer with (n = 11) or without (n = 6) liver metastasis. The reservoir was transcutaneously implanted with the help of angiography. The inferior pancreatic artery (IPA) was embolized to achieve delivery of the pancreatic blood supply through only the celiac artery. The systemic administration of gemcitabine was combined with the infusion of 5-fluorouracil via the reservoir. Treatment effects were evaluated based on the primary tumor size, liver metastasis, and survival time and factors such as tumor size, tumor location, and stage of pancreatic carcinoma; the embolized arteries were analyzed with respect to treatment effects and prognosis. RESULTS: A catheter was fixed in the gastroduodenal artery and splenic artery in 10 and 7 patients, respectively. Complete peripancreatic arterial occlusion was successful in 10 patients. CT showed a decrease in tumor size in 6 of 17 (35%) patients and a decrease in liver metastases in 6 of 11 (55%) patients. The survival time ranged from 4 to 18 months (mean +/- SD, 8.8 +/- 1.5 months). Complete embolization of arteries surrounding the pancreas was achieved in 10 patients; they manifested superior treatment effects and prognoses (p < 0.05). CONCLUSION: In patients with advanced pancreatic cancer, long-term CTAI with systemic chemotherapy appeared to be effective not only against the primary tumor but also against liver metastases. Patients with successfully occluded peripancreatic arteries tended to survive longer.

Randomized comparison of intra-arterial chemotherapy versus intra-arterial chemotherapy and gelfoam embolization for treatment of advanced cervical carcinoma.

PURPOSE: We evaluated the effects of intra-arterial infusion therapy by comparing the results obtained with a combination of intra-arterial anticancer drugs with and without transcatheter arterial embolization (TAE) in patients with cervical cancer. METHODS: Between April 1999 and March 2003, intra-arterial therapy was administered to 45 patients (mean age 49 years) with cervical cancer. Of these, 18 had stage IIb , 4 had stage IIIa, 19 had stage IIIb, and 4 had stage IVb cancer; the histopathologic types were squamous cell carcinoma (n = 35), adenocarcinoma (n = 8), and adenosquamous carcinoma (n = 2). A total of 45 patients gave their informed consent and were randomized on a continuous basis into one of three groups according to the therapeutic protocols: group A consisted of 15 patients who received cisplatin, group B consisted of 17 patients who received cisplatin, mitomycin, doxorubicin hydrochloride, and 5-fluorouracil, and group C consisted of 13 patients who received cisplatin and TAE. Each protocol was administered twice with a 3 week interval between treatments. The efficacy of treatment was evaluated on the basis of the tumor reduction ratio (%) using MR imaging and the side effects were analyzed. RESULTS: In groups A, B, and C, the tumor reduction ratio was 54%, 84%, and 86%, respectively; it was significantly greater in groups B and C than in group A (p < 0.01). The difference between groups B and C was not statistically significant. Although all group C patients developed severe pain after TAE, the pain was controlled with analgesics. Thrombocytopenia occurred in 6 of 17 (35%) group B patients. CONCLUSION: Group B and C patients had better tumor reduction than those in group A. Fewer hematologic complications occurred in group C patients compared with group B.

Effects of adaptive focusing for image transmission through an inhomogeneous layer.

In a previous paper we proposed an adaptive focusing operation in a one-way image transmission system using phase conjugation to maximize the transmission capability through an inhomogeneous medium. Here the required focusing precision in the proposed system is analyzed and some experimental results are presented to validate the analysis.

Improvement of image transmission using phase conjugation by magnification of the transmission field.

The field generated by the phase conjugator is magnified to increase the image transmission ability.

Electron transfer reaction of stellacyanin at a bare glassy carbon electrode.

Direct (unmediated) electrochemistry of Rhus vernicifera stellacyanin at a glassy carbon electrode has been briefly investigated in phosphate buffer. The voltammetry was practically independent of the buffer concentration, suggesting that the interaction between stellacyanin and the glassy carbon electrode is mainly realized through the hydrophobic interaction. The quasi-reversible process was found to be diffusion controlled at a sweep rate < 80 mVs-1. From stellacyanin concentration dependence, a transformation from linear diffusion to radial diffusion was observed. Two-step voltammetry was affected by translocations of the active site (rotation of the protein molecule on the electrode surface and diffusion). Activation energies for reduction and oxidation processes were determined to be 24 kJmol-1 and 54 kJmol-1, respectively, by the stationary method, and 15 kJmol-1 and 66 kJmol-1, respectively, by cyclic voltammetry. The considerable difference in the activation energies is supposedly due to the reduction and oxidation which are performed utilizing different electron-transfer pathways or because only one electron-transfer pathway (probably through His92) is significantly changed during the reorganization between the oxidized and reduced forms. The fact that the diffusion constant estimated from one-step voltammetry (Dox = 4.2 x 10(-9) cm2 s-1 for 484 microM stellacyanin) is much smaller than that determined from cyclic voltammetry (7.5 x 10(-7) cm2 s-1) derives from the fact that motions of the stellacyanin molecule (rotation leading to translocation of the active site and diffusion) are not fast enough to allow data from potential step voltammetry to be treated as the reversible process, but are fast enough to allow data from cyclic voltammetry to be treated as a diffusion-controlled process.

Detection of subsurface defects using phase conjugate waves and forced vibration.

In four-wave mixing in BSO crystal, a periodic forced vibration is applied to both the object under test and the standard object to provide signal and reference waves, respectively. The system images subsurface defects of the test object by converting the difference of vibration between the test and the standard objects into image intensity. The principle and basic experimental results are given.

Multilayered deformable mirror using PVDF films.

A 1-D deformable mirror which uses multilayered PVDF piezoelectric films as the actuators is proposed. First, a set of desired wave fronts is considered and the electrode shape of each film is designed so that the film generates one component of the set. In actual operation of the mirror a combination of the supply voltages is used to control the surface profile. The principle of construction and several basic experimental results are presented.