OBJECTIVE: Although simultaneous measurements of PET and magnetic resonance imaging (MRI) can provide interesting results in molecular imaging research, most of the combined systems are huge and animal handling in the system is not easy. To minimize these problems, we developed a compact integrated PET/MRI (iPET/MRI) system for small animals. METHODS: For the iPET/MRI system, a new MR-compatible PET and a permanent magnet open MRI were designed. In the MRI, a tunnel is opened at the yoke of the magnet. The position-sensitive photo-multiplier tubes (PSPMTs) of the MR-compatible PET are positioned at the back of the yoke where the magnetic field is sufficiently low. The scintillators for the PET system are positioned at the center of the MRI magnets, and the direction of the scintillation photons is changed by slanted light guides, and they are fed to the PSPMTs by 75 cm long optical fiber bundles. The PET detectors employed two types of LGSO crystals (1.9 mm x 2.2 mm x 6 mm and 7 mm) with different decay times (33 and 43 ns) for depth of interaction detection. Sixteen optical fiber-based block detectors are arranged in a 112 mm diameter ring. RESULTS: The transaxial field-of-view (FOV) of the PET system is ~80 mm, and the axial FOV is 21 mm which can be enlarged by the axial motion of the PET detector ring during MRI acquisition. The transaxial and axial resolutions at the center of the PET system was 2.9 and 2.4 mm FWHM, respectively. The absolute sensitivity was 1.5% at the center of the axial FOV. Phantom images revealed no artifact in either the PET or MRI images. We successfully obtained simultaneously measured small animal images using the iPET/MRI system. CONCLUSION: The open geometry of the developed iPET/MRI facilitates easy accessibility to the subject. The iPET/MRI system appears to be a promising tool for molecular imaging research.

PURPOSE: To analyze rectal bleeding prognostic factors associated with prostate brachytherapy (PB) or in combination with external-beam radiation therapy (EBRT) and to examine dosimetric indications associated with rectal bleeding. MATERIALS AND METHODS: The study included 296 patients followed up for >36 months (median, 48 months). PB was performed alone in 252 patients and in combination with EBRT in 44 patients. PB combined with EBRT is indicated for patients with a Gleason score >6. The prescribed dose was 144 Gy for monotherapy and 110 Gy for PB + EBRT (44-46 Gy). RESULTS: Although 9.1% who received monotherapy had 2.3% grade 2 rectal bleeding, 36.3% who received combined therapy had 15.9% grade 2 rectal bleeding. Combined therapy was associated with higher incidence of rectal bleeding (P = 0.0049) and higher percentage of grade 2 bleeding (P = 0.0005). Multivariate analysis revealed that R-150 was the only significant factor for rectal bleeding, and modified Radiation Therapy Oncology Group (RTOG) grade in monotherapy and biologically equivalent dose (BED) were significant for combined therapy. Moreover, grade 2 rectal bleeding increased significantly at D90 > 130 Gy. CONCLUSION: Although R-150 was the significant prognostic factor for rectal bleeding and modified RTOG rectal toxicity grade, BED was the significant prognostic factor for modified RTOG rectal toxicity grade.

PURPOSE: To determine the reproducibility and precision of postimplant dosimetry following (125)I prostate brachytherapy (PB) and to evaluate the effects of learning and experience in CT-based postimplant dosimetry. MATERIALS AND METHODS: One-month postimplant CT data from two patients who underwent PB alone or combined therapy (PB + EBRT) were sent to 28 institutions for postimplant dosimetry and analyzed in 2006 (study 1). Similarly, 1-month postimplant CT data from two other patients were also analyzed in 2008 (study 2; 23 institutions). For both modalities in studies 1 and 2, the variance of the difference between CT-based D90 at each institution and CT/MRI fusion-based D90 was estimated. RESULTS: In monotherapy, F test and Mann-Whitney U test revealed no significant difference in the variance in studies 1 and 2 (P = 0.72, 0.46). In combined therapy, the variance significantly converged in study 2 compared with study 1 (P < 0.05). Even in the two studies, however, the difference between the median CT-based D90 and fusion-based D90 was at least 20-30 Gy. CONCLUSION: Marked interobserver variability was seen in the prostate volume and D90 with CT alone. The precision of postimplant dosimetry based on CT alone was revealed to be limited.

PURPOSE: Interobserver differences in postimplant dosimetry based on computed tomography (CT) and CT/magnetic resonance imaging (MRI) fusion images were assessed to evaluate the efficacy of the fusion image. In addition, the part of the prostate contour responsible for the interobserver differences in CT was identified. MATERIALS AND METHODS: In June 2008, 1-month postimplant CT data from two patients who underwent 125I prostate brachytherapy were sent to 90 institutions for postimplant dosimetry. Subsequently, MRI data from the same patients were sent for fusion-based postimplant dosimetry. The variance of the difference between MRIbased D90 and CT-based or fusion-based D90 was compared. Prostate volume on CT was plotted on the y-axis against the position of the most cranial and caudal slices in the prostate contour delineated at each institution to analyze interobserver differences. RESULTS: The prostate volume from CT was significantly greater than from the CT/MRI fusion image (P = 0.0014). Fusion-based variance was significantly greater than CT-based variance (P < 0.01). CT-based postimplant dosimetry showed that 88%-96% of the institutions had an apical and basal position within a range of 5 mm. CONCLUSION: There were marked interobserver differences in CT/MRI fusion-based postimplant dosimetry.

We investigated a foodborne norovirus outbreak in a hospital and an attached long-term care facility (LTCF). An at-risk group of 698 people was identified, which included staff, hospital patients, LTCF residents, and adult daycare users who shared consumption of food prepared in a central kitchen. Three different diets were prepared in three separate sections: a standard diet, a special diet, and a diet for residents at the LTCF. During the first 3 days of the outbreak, 47 (16%) of 285 staff members and 55 (13%) of 413 patients became symptomatic. Eating the standard diet was significantly associated with a risk of illness for staff members (relative risk [RR], 18.13; 95% confidence interval [CI], 5.76-57.03) and patients (RR, 2.12; 95% CI, 1.05-4.31). Some stool samples were positive for norovirus GII/4. The standard diet may have been contaminated while being prepared in the central kitchen.

We present a measurement of the W boson mass in W-->enu decays using 1 fb;{-1} of data collected with the D0 detector during Run II of the Fermilab Tevatron collider. With a sample of 499830 W-->enu candidate events, we measure M_{W}=80.401+/-0.043 GeV. This is the most precise measurement from a single experiment.

We present a measurement of the mass difference between t and t[over ] quarks in lepton+jets final states of tt[over ] events in 1 fb;{-1} of data collected with the D0 detector from Fermilab Tevatron Collider pp[over ] collisions at sqrt[s]=1.96 TeV. The measured mass difference of 3.8+/-3.7 GeV is consistent with the equality of t and t[over ] masses. This is the first direct measurement of a mass difference between a quark and its antiquark partner.

BACKGROUND & AIMS:: Caudal-related homeodomain transcription factors CDX1 and CDX2 regulate gut development and differentiation of intestinal epithelial cells; they are candidate tumor suppressors of colorectal carcinomas. Because the functions of CDX1 and CDX2 in the colonic epithelium are not fully understood, we sought to identify genes that they target. METHODS:: We conducted a chromatin immunoprecipitation (ChIP) screen to identify genes that bind the CDX transcription factors. Expression of target genes was analyzed in colon cells and tissues from Cdx1 not(-/-), Cdx2(+/-), Apc(+/Delta716), and wild-type (control) mice. RESULTS:: Using the ChIP screen, we identified solute carrier family 5, member 8 ( SLC5A8, also known as SMCT1) as a direct target of CDX1 and CDX2. CDX transcription factors bind to the promoter region of SLC5A8and transactivate SLC5A8reporter constructs. Overexpression of Cdx1 or Cdx2 in human colon cancer cell lines induced expression of endogenous SLC5A8, whereas CDX1 and CDX2 knockdowns reduced its level. Consistently, Slc5a8 expression was significantly reduced in colons of Cdx1 not(-/-)or Cdx2(+/-)mice compared with wild-type mice. Slc5a8 levels were also reduced in colonic adenomatous polyps and hamartomas from Apc(+/Delta716) and Cdx2(+/-) mutant mice, respectively, compared with adjacent normal colon tissues. CONCLUSIONS:: CDX1 and CDX2 bind the promoter region of SLC5A8 and upregulate its expression in cultured cells and in colonic epithelium. SLC5A8 transports monocarboxylates such as pyruvate, lactate, and butyrate; CDX1 and CDX2 might therefore regulate the uptake of these substances in the colon.

Pharmacokinetics of tebipenem pivoxil (TBPM-PI), a novel oral carbapenem antibiotic, were known in various laboratory animal.(1) In mouse, rat, dog and monkey, TBPM-PI were absorbed quickly, and the bioavailability was (71.4, 59.1, 34.8 and 44.9%, respectively.(2) TBPM-PI was quickly converted to tebipenem (TBPM), an active form of TBPM-PI. Through blood circulation, TBPM was distributed into the kidney at a high concentration and eliminated quickly. There was no other tissue than the kidney, in which TBPM was highly distributed and remained for a long time. In addition, low penetration to the central nervous system was confirmed. The penetration ratio of TBPM to ELF, that is the ratio of ELF concentration to plasma concentration of TBPM, was 21.8 +/- 14.7%.(3) Serum protein bindings of TBPM in the range of 0.1-100 microg/ml were 90.4-98.3% for mouse, 78.5-90.0% for rat, 15.7-18.7% for dog, 35.3-39.3% for monkey and 59.7-73.9% for human.(4) In vitro metabolism was investigated in plasma, liver S9 fractions and small intestinal S9 fractions derived from infant and adult animals. TBPM-PI was transformed into TBPM quickly in any matrices. It was confirmed that absorbed TBPM-PI was quickly transformed into TBPM or LJC 11,562 (opened ring TBPM) in the plasma after oral administration of 14C-TBPM-PI to infant or adult rat and monkey. TBPM-PI and opened ring TBPM-PI was not detected in plasma and urine samples. In rat and monkey, the oral absorption, distribution, metabolite and excretion of TBPM-PI were not so much different between infant and adult animals.(5) Liver metabolic enzyme system was little affected by 7-days repeated administration of 1-100 mg/kg TBPM-PI. IC50 values of TBPM-PI and TBPM for human CYP isoforms were estimated to be 100 microg/ml or higher.(6) After single oral administration of 10 mg/kg 14C-TBPM-PI to rat, 36.9-42.7% and 58.3-62.2% of radioactivity was excreted to urine and feces, respectively, by 120 hours after administration. The majority of dosage was excreted out of body by 48 hours after administration. After single intravenous administration of 10 mg/kg 14C-TBPM, 87.4% and 11.4% of radioactivity was excreted in urine and bile, respectively, by 24 hours after administration. The majority of dosage was excreted out of body by 4 hours after administration.

Ventriculo-atrial shunt infection (VASI) may lead to sepsis and/or nephritis, making early diagnosis critical. VASI is usually diagnosed by cerebrospinal fluid culture conducted after ventricular puncture or shunt removal, both of which are invasive. Non-invasive attempts at diagnosis, however, present a nonspecific clinical picture unless shunt dysfunction is present. A 57-year-old woman treated with ventriculo-atrial shunt 10 months earlier due to hydrocephalus following subarachnoid hemorrhage developed a fever but evidenced no infected organs in general examination although Staphylococcus epidermidis was isolated several times upon blood culture. Enhanced brain computed tomography (CT) showed neither abnormal findings nor changes in ventricular size and no shunt dysfunction was demonstrated clinically. In cerebrospinal fluid examination, the protein level was 137 mg/dL and cell count and bacteriological findings were normal. 10 days later, however, the cell count and bacteriological findings were normal but protein was 180 mg/dL. The cerebrospinal fluid protein increase indicated VASI, and the shunt was removed. The woman's fever was immediately alleviated and Staphylococcus epidermidis was detected in the cerebrospinal fluid culture of the specimen from the shunt tip and its periphery. Blood culture is useful for identifying bacterial etiology of VASI if neither cerebrospinal fluid cell count increases nor abnormal bacteriological findings are observed, provided that cerebrospinal fluid protein increase are observed in serial measurement.