Interferometer-based phase-contrast X-ray computed tomography of colon cancer specimens: comparative study with 4.74-T magnetic resonance imaging and optical microscopy

OBJECTIVE: Phase-contrast X-ray computed tomography (PCCT) with an interferometer can reveal the inner soft tissue structures of biological objects without contrast agent, and the image quality is thought to resemble that of magnetic resonance imaging (MRI). Comparative study among PCCT, MRI, and optical microscopy was undertaken. METHODS: Three formalin-fixed colon cancer specimens from nude mice were imaged both by PCCT with a reconstructed volumetric resolution of (0.018)3 mm3 and 4.74-T MRI with that of (0.075)3 mm3. RESULTS: Phase-contrast X-ray computed tomography with an interferometer clearly demonstrated the inner structures of colon cancer masses, such as cancer, necrosis, surrounding tumor vessels, and skin, in a similar way to low-magnified optical microscopic images and had approximately 4.0-fold higher signal-to-noise ratio than MRI. CONCLUSIONS: With formalin-fixed biological samples, PCCT exhibited higher image quality than MRI and was thought to be suitable for detailed imaging of soft tissue with high volumetric resolution.     

Tumor suppressor Prdx1 is a prognostic factor in esophageal squamous cell carcinoma patients

Peroxiredoxins (Prdxs) are a family of antioxidant enzymes that are also known as scavengers of peroxide in mammalian cells. Some reports have shown that the overexpression of Prdx1, which is one of the peroxiredoxins that is a ubiquitously expressed protein, was related to a poor prognosis in several types of human cancers. In this study, we investigated the expression levels of Prdx1 in esophageal squamous cell carcinoma by immunohistochemistry, and the correlation between the Prdx1 expression and the clinical status was elucidated. Immunohistochemical staining was performed in 114 samples which were collected from surgical esophageal cancer specimens. Cytoplasmic staining of Prdx1 was evaluated based on the following scoring criteria: Grade I, negative or weak staining; Grade II, moderate staining; and Grade III, strong staining. The percentage of patients with a Grade I expression of Prx1 was 20% (23 of 114), 44% had Grade II (50 of 114), and 36% had Grade III (41 of 114). The Prdx1 immunoreactivity showed an inverse significant correlation with T-category (P<0.0001), lymph node metastasis (P=0.048), and stage (P=0.001). In addition, the patients with tumors exhibiting a reduced Prdx1 expression had shorter overall survival (P=0.022) in comparison to the patients with tumors which had a higher Prdx1 expression. Currently, Prdx1 has been shown to act as a tumor suppressor. Our results provide strong evidence that the reduced Prdx1 expression is an important factor in esophageal squamous cancer progression and could serve as a useful prognostic marker.     

Infectious mononucleosis]

Infectious mononucleosis(IM) is a primary Epstein-Barr virus (EBV)infection. Since heterophil antibody negative IM is common in Japan, EBV antibody(presence of VCA-IgM or anti-EA, high titers of VCA-IgG in the absence of anti-EBNA) is useful for serologic diagnosis of IM. Although EBV causes the continuous growth of lymphoid cell lines in vitro and causes malignant diseases such as Burkitt lymphoma, nasopharyngeal cancer and malignant lymphomas in immunocompromised patients, IM is usually self-limiting, and after primary infection EBV persists in B cells throughout life without producing symptoms. In the present study, we studied CD8+ lymphocytes of patients with IM and demonstrate an increase in lymphocytes expressing HLA-DR and CD45RO, increase of intracellular pH, elevated plasma levels of sCD8, indicating activation of the subset. We also demonstrate activation of CD4+ T lymphocytes and gamma delta T lymphocytes. Activation of these immune systems in response to EBV is supposed to play an important role in assuring the benign course of IM.     

Degradation of c-Fos protein expressed by N-methyl-D-aspartic acid in nuclear fractions of murine hippocampus.

In both nuclear and cytosolic fractions of murine hippocampus, constitutive expression was seen with Fra-2 protein, but not with other Fos family members tested including c-Fos, Fos-B and Fra-1 proteins. Fos-B protein was only detected in nuclear fractions. The systemic administration of N-methyl-D-aspartic acid (NMDA) induced marked and transient expression of c-Fos protein, but not other family members, in both hippocampal fractions 2 h later. In vitro incubation at 30 degrees C led to more rapid degradation of inducible c-Fos protein than constitutive Fra-2 protein in nuclear fractions obtained 2 h after the administration of NMDA, without significantly affecting that of both member proteins in cytosolic fractions. The addition of phosphatase inhibitors significantly delayed the initial degradation rate of inducible c-Fos protein, with concomitant facilitation of that of constitutive Fra-2 protein, in nuclear fractions. The addition of protease inhibitors also delayed the initial degradation of constitutive Fra-2 protein, without markedly altering that of inducible c-Fos protein, in nuclear fractions. Immunoprecipitation analysis revealed that NMDA induced phosphorylation of c-Fos protein on tyrosine residues in nuclear fractions to a lesser extent than that on serine residues 2 h after administration. These results suggest that NMDA signals may be propagated to the nucleus to induce both expression and degradation of c-Fos protein through a molecular mechanism associated with phosphorylation on serine and/or tyrosine residues in murine hippocampus.     

Intrauterine therapy for the acutely enlarging fetal cystic hygroma

Enlarged fetal cystic hygroma is known to cause life-threatening complications such as fetal hydrops and neonatal respiratory difficulty. A 28-year-old Japanese woman, gravida 0, presented with fetal cystic hygroma at 23 weeks of gestation. There were no other structural malformations or hydrops detected by ultrasonographic examination. In addition, the karyotype was diagnosed as normal through amniotic fluid analysis. The cystic lesion showed acute enlargement and intrauterine sclerotherapy using OK-432 was performed at 26 weeks. The size of the cyst initially decreased, which was followed by a gradual increase. A viable 3,098 g male infant was delivered by cesarean section at 37 weeks without any other complications. The infant had no clinical difficulty during the neonatal period and later underwent a surgical removal of the remaining cystic lesion. Cases of fetal cystic hygroma showing acute enlargement without other complications are considered good candidates for intrauterine therapy to prevent subsequent complications.     

Contrast-enhanced CT and diffusion-weighted MR imaging: Performance as a prognostic factor in patients with pancreatic ductal adenocarcinoma

Objective

To determine whether contrast enhancement of CT and apparent diffusion coefficient on diffusion-weighted MR imaging are important parameters that can predict outcomes for patients with pancreatic ductal adenocarcinoma.

Materials and methods

Ninety-two patients with histologically confirmed pancreatic ductal adenocarcinoma who underwent quadriphasic CT (including unenhanced, pancreatic parenchymal, portal venous and delayed phases) and fat-suppressed single-shot echo-planar diffusion-weighted MR imaging at 3.0 T were retrospectively analyzed to investigate prognostic factors. Overall survival curves were drawn using the Kaplan–Meier method. Effects on survival of variables including age, sex, tumor location, tumor size, TNM stage, carbohydrate antigen 19-9, carcinoembryonic antigen, treatment, tumor contrast enhancement and apparent diffusion coefficient values were analyzed in univariate analysis using the log-rank test. Variables were analyzed in multivariate analyses using the Cox proportional hazards regression model.

Results

Median survival for the entire patient population was 18.2 months. Higher contrast enhancement during all phases was associated with significantly longer overall survival (P < 0.001 for all phases). The difference in overall survival between groups divided by median apparent diffusion coefficient value was not significant (P = 0.672). TNM stage (P = 0.026) and tumor contrast enhancement on CT (P = 0.027) were significantly related to survival in multivariate analysis.

Conclusions

Poor enhancement of pancreatic adenocarcinomas on enhanced CT is associated with reduced patient survival.     

Application of a medium-energy collimator for I-131 imaging after ablation treatment of differentiated thyroid cancer

Purpose

High-energy (HE) collimators are usually applied for I-131 imaging after ablation treatment of differentiated thyroid cancer (DTC). However, purchase of HE collimators has been avoided in many nuclear medicine departments because the HE collimators are more expensive than other collimators. In this study, we compared the I-131 imaging using HE- and medium-energy (ME) collimators, which is more versatile than HE collimators.

Materials and methods

To simulate DTC patients with extra-thyroid beds, a phantom of acrylic containers containing I-131 was used. To simulate patients with thyroid beds, four phantoms representing extra-thyroid beds were arranged around the phantom representing normal thyroid tissues. Patients administered 1.11 or 3.70 GBq NaI-131 were also evaluated. Whole-body imaging and SPECT imaging of the phantoms and patients performed using HE-general-purpose (HEGP) and ME-low-penetration (MELP) collimators, and full-width at half maximum (FWHM) and percent coefficient of variation (%CV) were measured.

Results

In the extra-thyroid beds, FWHM and %CV with MELP were negligibly different from those with HEGP in whole-body imaging. Although FWHM with MELP was a little different from that with HEGP in SPECT imaging, %CV with MELP was significantly higher than that with HEGP. In the thyroid beds, only an extra-thyroid bed including higher radioactivity was identified in whole-body imaging with both collimators. Although SPECT images with MELP could not clarify extra-thyroid beds with low radioactivity, HEGP could identify them. In patients, although some whole-body images with MELP could not detect extra-thyroid beds, whole-body imaging with HEGP and SPECT imaging with both collimators could detect them.

Conclusions

Although HEGP is the best collimator for I-131 imaging, MELP is applicable for not only whole-body imaging but also SPECT imaging.     

Pro-oxidative effect of alpha-tocopherol in the oxidation of LDL isolated from co-antioxidant-depleted non-diabetic hemodialysis patients

The association between the antioxidants in LDL and the oxidizability of LDL assessed by the oxidation lag time during copper ion-catalyzed oxidation was investigated in 69 non-diabetic hemodialysis patients and 23 healthy volunteers. The concentrations of co-antioxidants, including ubiquinol-10, lycopene and beta-carotene, in LDL were significantly lower in the hemodialysis patients than in the healthy volunteers, while there was no difference in the alpha-tocopherol concentration between the groups. The lag time showed a significantly positive correlation with the alpha-tocopherol level (r = 0.62, P < 0.01) in the healthy subjects, but a significantly negative correlation (r = -0.38, P < 0.05) in the hemodialysis patients. Furthermore, in vitro incubation of LDL with alpha-tocopherol prolonged the lag time in the healthy subjects, but shortened it in the hemodialysis patients. These results suggested that the alpha-tocopherol might exert the pro-oxidative effect in co-antioxidant-depleted LDL that was isolated from the hemodialysis patients. Despite such co-antioxidant depletion and the pro-oxidative effect of alpha-tocopherol, the lag time in the hemodialysis patients was not statistically different from that in the healthy volunteers. This might have been because the polyunsaturated fatty acids concentration, another determinant of the lag time, in LDL was less in the hemodialysis patients than in the healthy controls.