"Donut's shape" radiosurgical treatment planning for large cystic metastatic brain tumors

BACKGROUND

Radiosurgical management of large cystic metastatic brain tumors represents a significant challenge. Nevertheless, modified dose planning has shown beneficial results in such cases.

METHOD AND RESULTS

"Donut's shape" radiosurgical treatment planning is based on the chain-like application of multiple, small-sized isocenters for selective coverage of the contrast-enhancing tumor capsule and minimal irradiation of the central cystic area. Such an approach was used for the management of large cystic intracranial metastases, which were not accompanied by a significant mass effect and did not require immediate volume reduction. Treatment was done using Leksell Gamma Knife model C with automatic positioning system. The majority of treated lesions showed significant shrinkage after radiosurgery and no major complications were met.

CONCLUSION

Large cystic metastatic brain tumors may be successfully treated with gamma knife radiosurgery alone using the proposed "donut's shape" dose planning with coverage of the contrast-enhancing tumor capsule by multiple small-sized isocenters.

The periodontal pathogen Porphyromonas gingivalis induces the Epstein-Barr virus lytic switch transactivator ZEBRA by histone modification

Epstein-Barr virus (EBV) is a ubiquitous human herpesvirus that usually results in latent infection of B cells. The EBV BZLF1 gene product ZEBRA is a master regulator of the transition from latency to the lytic replication cycle. In the latent state, hypoacetylation of histone proteins in the BZLF1 promoter by histone deacetylases (HDACs) is primarily involved in maintaining EBV latency. Although the mechanism that regulates the switch between latency and lytic replication has been a central research focus in EBV infection, the causal link between HDAC inhibition and the disruption of viral latency is not well understood. Periodontal disease is a complex chronic inflammatory disease caused by subgingival infection with oral anaerobic bacteria, typically Porphyromonas gingivalis. Periodontal disease occurs worldwide and is among the most prevalent microbial diseases in humans. In this study, we examined the biological effect of P. gingivalis infection on EBV reactivation and found that P. gingivalis induced expression of ZEBRA. This activity was associated with supernatant from bacterial culture, but not with other bacterial components such as lipopolysaccharide or fimbriae. We demonstrated that culture supernatant from P. gingivalis, which contained high concentrations of butyric acid, inhibited HDACs, thus increasing histone acetylation and the transcriptional activity of the BZLF1 gene. Chromatin immunoprecipitation assays revealed that HDACs were present in the BZLF1 promoter during latent state and that they were dissociated from the promoter concomitantly with the association of acetylated histone H3, upon stimulation by culture supernatant from P. gingivalis. Thus, P. gingivalis induced EBV reactivation via chromatin modification, and butyric acid-a bacterial metabolite-was responsible for this effect. These findings suggest that periodontal disease is a risk factor for EBV reactivation in infected individuals and might therefore contribute to progression of EBV-related diseases.

The effect of gantry and collimator angles on leaf limited velocity and position in dynamic multileaf collimator intensity-modulated radiation therapy

The purpose of the study is to evaluate the limiting velocity (LV) of a multileaf collimator and the leaf position in various collimator and gantry angles. Both leading leaves and trailing leaves began to move with a constant acceleration from 0 to 4 cm s(-1). When the beam hold occurred, the leaf velocity was defined as the leaf LV. Dynamic irradiation was performed at eight gantry angles of every 45 degrees with three different collimator angles. The analysis of the LV and the leaf position was performed with a log file from a leaf motion controller. The mean LVs for Varian Clinac 21EX (21EX) ranged from 2.51 to 3.10 cm s(-1). The mean LVs for Clinac 600C ranged from 2.91 to 3.12 cm s(-1). When only central 5 mm leaves of 21EX moved, LVs were significantly higher than those when all 60 pairs of leaf moved, while the leaf position inconsistencies of the two accelerators were within 1 mm at the leaf velocities from 0.5 to 2.0 cm s(-1). It was recognized that the LV was affected by gravity. This measurement method can be utilized as routine quality assurance for a dynamic multileaf collimator (DMLC) is and easily reproducible.

[Primary anterior mediastinal huge lipoma: report of a case]

We report a case of anterior mediastinal lipoma. A 71-year-old female was admitted for cough. A fat density tumor from anterior mediastinum to left thoracic cavity was found by chest X-ray, chest computed tomography (CT) and magnetic resonance imaging (MRI). Defect of left dorsal diaphragm was suspected and there was a possibility that the tumor was connected to retroperitoneum. Under the preoperative diagnosis of a benign huge mediastinal lipoma, we conducted an operation. At 1st, we observed by thoracoscopy and made sure that the mass was primary anterior mediastinal tumor and not connected to retroperitoneum. Through the median sternotomy, we completely resected the tumor with thymus. The tumor showed 27 cm in diameter, and histopathological diagnosis of the tumor was benign lipoma. Lipoma of the mediastinum is very rare and about 0.3% of all mediastinal tumors. It is sometimes difficult to distinguish huge lipoma from liposarcoma only by clinical examinations such as CT scan or MRI. We evaluated the condition of the tumor by thoracoscopic observation, and the tumor was safely and completely resected by median sternotomy.

First results from the new RIKEN superconducting electron cyclotron resonance ion source (invited)

The next generation heavy ion accelerator facility, such as the RIKEN radio isotope (RI) beam factory, requires an intense beam of high charged heavy ions. In the past decade, performance of the electron cyclotron resonance (ECR) ion sources has been dramatically improved with increasing the magnetic field and rf frequency to enhance the density and confinement time of plasma. Furthermore, the effects of the key parameters (magnetic field configuration, gas pressure, etc.) on the ECR plasma have been revealed. Such basic studies give us how to optimize the ion source structure. Based on these studies and modern superconducting (SC) technology, we successfully constructed the new 28 GHz SC-ECRIS, which has a flexible magnetic field configuration to enlarge the ECR zone and to optimize the field gradient at ECR point. Using it, we investigated the effect of ECR zone size, magnetic field configuration, and biased disk on the beam intensity of the highly charged heavy ions with 18 GHz microwaves. In this article, we present the structure of the ion source and first experimental results with 18 GHz microwave in detail.

Ultrasonic propagation of a metallic domain in Pr0.5Ca0.5CoO3 undergoing a photoinduced insulator-metal transition

Femtosecond optical response was investigated on a perovskite-type cobalt oxide, Pr0.5Ca0.5CoO3 during an insulator-metal (I-M) transition accompanied with the change in spin configuration. After photoirradiation at 30 K, the reflectivity showed a sudden and large increase with subsequent variation depending on the observed photon energy. An exact calculation of Maxwell's equations for the Pr0.5Ca0.5CoO3 after the photoirradiation enabled us to observe the ultrafast dynamics of I-M phase transition and the motion of the photonically created metallic domain at the velocity of ultrasonic wave.

Combined surgery, radiation, and chemotherapy for oligodendroglial gliomatosis cerebri

Gliomatosis cerebri (GC), which mainly consists of oligodendroglial tumour cells, is rare and six cases have been documented to date. We present a new case of oligodendroglial gliomatosis cerebri with a favourable response to combination treatment using surgery, radiotherapy and chemotherapy.

[Video-assisted thoracic surgery for clinical stage I lung cancer]

We evaluated our results of video-assisted thoracic surgery (VATS) performed for lung cancer over 8 years. Between April 2000 and October 2008, a total of 409 (60.9%) underwent VATS for lung cancer. Operative procedures as a radical operation were partial resection in 58 patients, segmentectomy in 64 patients, and lobectomy in 229 patients. There was 1 patient with operative death including hospital death due to pulmonary thromboembolism. In a median follow-up period of 21 months, the 5-year cause specific survival rate was 93.7%. According to operative procedures, the 5-year survival rate was 100% in patients underwent partial resection and segmentectomy, and 91.1% in patients underwent lobectomy. According to pathological stages, the 5-year survival rate was 98.8% in 289 patients with stage IA, 69.1% in 34 patients with stage IB, and 68.2% in 14 patients with stage IIIA. In conclusion, VATS lobectomy and VATS intentional limited resection can be performed with low mortality and good prognosis for clinical stage IA lung cancer patients.

[Gastrointestinal hemorrhage induced by percussive ventilator in an infant with chronic lung disease complicated after surgery for corrected transposition of the great arteries]

A newborn patient (birth weight 2,332 g) with corrected transposition of the great arteries developed chronic lung disease due to a severe heart failure and post operative several complications. We applied intrapulmonary percussive ventilation (IPV) to the patient. IPV improved oxygenation concomitant with the improvement of respiratory condition and chest X-ray finding. However, the patient suffered from upper gastrointestinal bleeding 15 days after initiation of IPV therapy. The bleeding was healed several days after temporal termination of IPV, but recurred with resuming IPV therapy. The patient was irritable throughout the IPV therapy, and thus gastrointestinal bleeding of the patient could be due to stress induced by IPV therapy. IPV may be useful for the management of respiratory disturbance, often observed in low birth weight patients with congenital heart defects. However, gastrointestinal bleeding may occur and should be considered as a possible complication associated with IPV therapy.

Darwin--a mission to detect and search for life on extrasolar planets

The discovery of extrasolar planets is one of the greatest achievements of modern astronomy. The detection of planets that vary widely in mass demonstrates that extrasolar planets of low mass exist. In this paper, we describe a mission, called Darwin, whose primary goal is the search for, and characterization of, terrestrial extrasolar planets and the search for life. Accomplishing the mission objectives will require collaborative science across disciplines, including astrophysics, planetary sciences, chemistry, and microbiology. Darwin is designed to detect rocky planets similar to Earth and perform spectroscopic analysis at mid-infrared wavelengths (6-20 mum), where an advantageous contrast ratio between star and planet occurs. The baseline mission is projected to last 5 years and consists of approximately 200 individual target stars. Among these, 25-50 planetary systems can be studied spectroscopically, which will include the search for gases such as CO(2), H(2)O, CH(4), and O(3). Many of the key technologies required for the construction of Darwin have already been demonstrated, and the remainder are estimated to be mature in the near future. Darwin is a mission that will ignite intense interest in both the research community and the wider public.