Thymic measurements in pathologically proven normal thymus and thymic hyperplasia: intraobserver and interobserver variabilities

RATIONALE AND OBJECTIVES

To determine the intraobserver and interobserver variabilities of thymic measurements on computed tomography (CT) in patients with pathologic diagnosis of thymic hyperplasia or normal thymus.

MATERIALS AND METHODS

Thirty-three patients with pathologic diagnosis of thymic hyperplasia (n = 25) or normal thymus (n = 8) who had identifiable thymus gland on CT were retrospectively studied. Two radiologists independently measured thymic size and CT attenuation. Concordance correlation coefficients (CCCs) and Bland-Altman plots were used to assess intraobserver and interobserver agreements.

RESULTS

The intraobserver and interobserver agreements of thymic diameters and the lobe length were moderate, with CCCs ranging from 0.73 to 0.89 and from 0.72 to 0.81, respectively. Higher agreement was noted among patients whose measurements were performed on the same CT image in two independent measurements, with intraobserver CCC ≥ 0.95 for diameters and length. After providing readers with an instruction for consistent selection of CT image for measurements, the intraobserver and interobserver agreements improved, resulting in CCCs ranging from 0.81 to 0.92 and from 0.77 to 0.85 for diameters and length, respectively. Thymic lobe thickness had the least agreement. CT attenuation measurements were highly reproducible, with CCCs ranging from 0.88 to 0.97. In patients with thymic CT attenuation >30 HU (Hounsfield unit), the attenuation measurements were more reproducible with narrower 95% limits of agreement.

CONCLUSIONS

Thymic size measurements had moderate-to-high intraobserver and interobserver agreements, when the instruction for consistent selection of images was provided to the readers. CT attenuation was highly reproducible, with higher reproducibility for thymic glands with >30 HU. Awareness of thymic measurement variability is necessary when interpreting measured values of normal thymus and thymic pathology on CT.

Tropomyosin-related receptor kinase B at the invasive front and tumour cell dedifferentiation in gastric cancer

Background:

Tropomyosin-related receptor kinase B (TrkB) promotes proliferation and invasion, relating to poor prognosis of various malignancies. We examined the role of TrkB at the invasive front of gastric cancer (GC) and its association with tumour cell dedifferentiation and tumour budding.

Methods:

Immunoreactive TrkB was evaluated at the tumour centre and margin using whole-tissue sections of 320 GC patients. Tumour cell dedifferentiation was defined as higher histologic grade at the tumour margin than the surface or tumour centre. Tumour budding was also scored on cytokeratin-stained sections.

Results:

Sixty-five patients (20%) showed higher TrkB expression at the invasive front (TrkB expression was higher at the tumour margin than tumour centre). It was significantly associated with several aggressive phenotypes in the full cohort (n=320). It showed a prognostic significance in test subgroup (n=98) and was identified as an independent prognostic factor (HR=2.09; 95% CI: 1.26–3.53) by multivariate analysis in validation subgroup (n=222). Twenty-one patients showed tumour cell dedifferentiation. In predominantly differentiated tumour, higher TrkB at the invasive front was significantly associated with tumour budding rather than tumour cell dedifferentiation.

Conclusions:

Assessment of immunoreactive TrkB at the invasive front by whole-tissue sections provides prognostic information for GC patients.

Intrathymic cyst: clinical and radiological features in surgically resected cases

AIM

To investigate radiological and clinical characteristics of pathologically proven cases of intrathymic cysts.

MATERIALS AND METHODS

The study population consisted of 18 patients (five males, 13 females; median age 56 years) with pathologically confirmed intrathymic cysts who underwent thymectomy and had preoperative chest computed tomography (CT) available for review. The patient demographics, clinical presentation, and preoperative radiological diagnoses were reviewed. CT images were evaluated for shape, contour, location of the cysts and the presence of adjacent thymic tissue, mass effect, calcifications, and septa. The size and CT attenuations of the cysts were measured.

RESULTS

The most common CT features of intrathymic cysts included oval shape (9/18; 50%), smooth contour (12/18; 67%), midline location (11/18; 61%), the absence of visible adjacent thymic tissue (12/18; 67%), and the absence of calcification (16/18; 89%). The mean longest diameter and the longest perpendicular diameter were 25 mm (range 17-49 mm) and 19 mm (range 10-44 mm), respectively. The mean CT attenuation was 38 HU (range 6-62 HU) on contrast-enhanced CT, and was 45 HU (range 26-64 HU) on unenhanced CT (p = 0.41). The CT attenuation was >20 HU in 15 of 18 patients (83%). Preoperative radiological diagnosis included thymoma in 11 patients.

CONCLUSION

In surgically removed, pathologically proven cases of intrathymic cyst, the CT attenuation was >20 HU in most cases, leading to the preoperative diagnosis of thymoma. Awareness of the spectrum of imaging findings of the entity is essential to improve the diagnostic accuracy and patient management.

Protective effect of pitavastatin, a 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitor, on ischemia-induced neuronal damage

We investigated the neuroprotective effects of a novel 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitor (pitavastatin) on ischemic neuronal damage in gerbils using immunohistochemistry. The animals were allowed to survive for 14 days after 5 min of ischemia induced by bilateral occlusion of the common carotid arteries. Five days after ischemia, severe neuronal cell loss was observed in the hippocampal CA1 sector. Prophylactic treatment with pitavastatin dose-dependently prevented the hippocampal CA1 neuronal cell loss 5 days after ischemia. Immunohistochemical study did not show the change of nNOS and iNOS expression in the hippocampus except for, in a few regions, up to 1 day after ischemia. Thereafter, the expression of iNOS was observed in the hippocampal CA1 sector 5 and 14 days after ischemia. In contrast, the expression of nNOS and eNOS gradually decreased in the hippocampal CA1 sector up to 14 days after ischemia. Prophylactic treatment with pitavastatin also prevented the expression of iNOS and the decrease of eNOS expression and the number of nNOS-positive cells in the hippocampal CA1 sector 5 days after ischemia. However, prophylactic treatment with pitavastatin at a dose of 10 mg kg(-1) did not change the immunoreactivity of iNOS and nNOS in the hippocampus at an early phase after ischemia. In contrast, this drug prevented the reduction of eNOS immunoreactivity in the hippocampal CA1 neurons at an early phase after ischemia. These findings demonstrate that the HMG-CoA reductase inhibitor pitavastatin can protect hippocampal CA1 neurons after transient forebrain ischemia through up-regulation of eNOS expression in this region. Thus pharmacological modulation of eNOS expression may offer a novel therapeutic strategy for cerebral ischemic stroke.

Orbital masses: the usefulness of diffusion-weighted imaging in lesion categorization

INTRODUCTION

Diffusion-weighted imaging (DWI) produces contrast among different kinds of tissues according to their diffusibility characteristics. The purpose of our study was to evaluate the role of DWI including measurement of apparent diffusion coefficient (ADC) values in recognizing benignancy or malignancy of orbital masses.

METHODS

A total of 39 orbital masses were evaluated visually for signal characteristics on DWI and ADC maps. ADC values were calculated for each lesion. Visual signal characteristics were compared using the Fisher exact test. Receiver operating characteristic (ROC) analysis was carried out to determine sensitivity and specificity for distinguishing malignant from benign lesions using ADC values. The Mann-Whitney U test was applied to compare the ADC values between orbital lymphomas and idiopathic orbital inflammatory (IOI) lesions, and between optic nerve sheath meningiomas and gliomas.

RESULTS

Visual assessment revealed no significant difference between benign and malignant lesions on DWI (p-value = 0.66). However, visual assessment of ADC maps revealed a statistically significant (p-value ≤ 0.0001) between benign and malignant lesions. ROC analysis showed a sensitivity of 83.33 % and a specificity of 85.71 % when using an optimal cut off ADC value of 0.84 × 10(-3) mm(2)/s for differentiating malignant from benign lesions. Significant differences in mean ADC values were observed between lymphomas and IOI lesions (p-value = 0.05), and between optic nerve sheath meningiomas and gliomas (p-value = 0.03).

CONCLUSION

DWI is useful for differentiating malignant and benign orbital tumors if accompanied by visual assessment of ADC maps and ADC value calculations.

MUC5B promoter polymorphism and interstitial lung abnormalities

BACKGROUND

A common promoter polymorphism (rs35705950) in MUC5B, the gene encoding mucin 5B, is associated with idiopathic pulmonary fibrosis. It is not known whether this polymorphism is associated with interstitial lung disease in the general population.

METHODS

We performed a blinded assessment of interstitial lung abnormalities detected in 2633 participants in the Framingham Heart Study by means of volumetric chest computed tomography (CT). We evaluated the relationship between the abnormalities and the genotype at the rs35705950 locus.

RESULTS

Of the 2633 chest CT scans that were evaluated, interstitial lung abnormalities were present in 177 (7%). Participants with such abnormalities were more likely to have shortness of breath and chronic cough and reduced measures of total lung and diffusion capacity, as compared with participants without such abnormalities. After adjustment for covariates, for each copy of the minor rs35705950 allele, the odds of interstitial lung abnormalities were 2.8 times greater (95% confidence interval [CI], 2.0 to 3.9; P<0.001), and the odds of definite CT evidence of pulmonary fibrosis were 6.3 times greater (95% CI, 3.1 to 12.7; P<0.001). Although the evidence of an association between the MUC5B genotype and interstitial lung abnormalities was greater among participants who were older than 50 years of age, a history of cigarette smoking did not appear to influence the association.

CONCLUSIONS

The MUC5B promoter polymorphism was found to be associated with interstitial lung disease in the general population. Although this association was more apparent in older persons, it did not appear to be influenced by cigarette smoking. (Funded by the National Institutes of Health and others; ClinicalTrials.gov number, NCT00005121.).

Is there visceral adipose tissue (VAT) intracellular hypercortisolism in human obesity?

The fact that obesity is a prominent feature of Cushing's syndrome (systemic hypercortisolism of adrenocortical origin) stimulated a 40-year search for evidence of systemic hypercortisolism in human obesity. That search has failed to find such evidence. For the past 15 years, however, studies have been done to evaluate a possible alternative type of hypercortisolism in obesity, namely visceral adipose tissue (VAT) intracellular hypercortisolism. The current review summarizes the evidence published so far about this possibility. There have been three types of evidence studied: direct measurement of the VAT levels of 11β-hydroxysteroid dehydrogenase type I (11-HSD-1), which converts biologically inactive cortisone to biologically active cortisol; direct measurement of splanchnic cortisol production; and evaluation of the effect of a specific inhibitor of 11-HSD-1 on metabolic abnormalities associated with obesity, particularly diabetes mellitus. The results are complex and difficult to interpret. Our conclusion is that the presence of VAT intracellular hypercortisolism in human obesity is possible but unlikely.

Mitochondrial swelling and microtubule depolymerization are associated with energy depletion in axon degeneration

Although mitochondrial dysfunction is intimately related to axonal degeneration following nerve injury, the molecular mechanisms of mitochondrial swelling and its mechanistic relation to axonal degeneration are largely unknown. Previous studies have demonstrated that axonal degeneration in the injured peripheral nerves shows two morphologically distinct phases: (1) A latency period (∼24h), in which the morphology of axonal cytoskeletons seems unchanged, followed by (2) an execution period (36-48h), which shows a catastrophic granular degeneration of most axonal structures in rodent axons. In the present study, we found that, in the sciatic nerve axotomy model, energy failure and microtubule depolymerization occurred during the latency period whereas mitochondrial swelling and neurofilament degradation started in the execution period. The energy repletion with NAD or an NAD/pyruvate mixture inhibited microtubule depolymerization, mitochondrial swelling and axonal degeneration in transected sciatic nerve axons. In addition, microtubule perturbing agents enhanced axonal degeneration and mitochondrial swelling. Extracellular calcium chelation did not affect energy failure, microtubule depolymerization or mitochondrial swelling, but it did prevent neurofilament degradation. These findings suggest that an early disturbance in energy dynamics regardless of mitochondrial swelling might be a key trigger for the initiation of axonal degeneration and that extracellular calcium influx is a late effector for neurofilament degradation.

Steady-State Visually Evoked Fields (SSVEF) associated with affective emotions

The aim of this study was to examine the SSVEFs associated with the processing of positive and negative impression images. We used the International Affective Picture System (IAPS) which is increasingly used in brain imaging studies to examine emotional processes. Their images also allow valence to be systematically investigated. All 200 images were categorized into three categories of "negative ", "positive " and "neutral " individually according to valence assessed by each subject after the MEG measurement. The peripheral square, i.e., frame, of the image was flickered black and white at 15 Hz while the image was kept stationary. Those images were randomly presented for 2.0 s on screen set at 120 cm in front of the subject. Ten healthy subjects participated. MEG recordings were made with a 122-channel whole-head MEG system in a magnetically shielded room. We made two-dipoles estimation of the averaged MEG signals and obtained the amplitude of souse waveform in 15 Hz component (using a band-pass filter at 14-16 Hz) of SSVEF in occipital area. The amplitude of the SSVEF source in the occipital area was larger for the negative impression images than the positive impression images (p<0.05). This result suggests that the amplitude of SSVEF that originated from the surrounding field of visual object was modulated by the emotional object and that the SSVEF could be a measure of emotion of subjects.

Clinical efficacy of two forms of intravenous iron--saccharated ferric oxide and cideferron--for iron deficiency anemia

Over 90% of iron deficiency anemia cases are due to iron deficiency associated with depletion of stored iron or inadequate intake. Parenteral iron supplementation is an important part of the management of anemia, and some kinds of intravenous iron are used. However, few studies have evaluated the clinical efficacy of these drugs. The purpose of this study was to compare and assess the clinical efficacy of two types of intravenous iron injection, saccharated ferric oxide (SFO) and cideferron (CF). Medical records were obtained for 91 unrelated Japanese anemia patients treated with SFO (n = 37) or CF (n = 54) from May 2005 to May 2010 at Gunma University Hospital. Patients treated with blood transfusion, erythropoietin or oral iron were excluded. Hemoglobin (Hb) values measured on day 0, 7 and 14 were used to assess the efficacy of intravenous irons. A significant increase was observed in the mean Hb value by day 14 of administration in both the CF group and SFO group, and the mean Hb increase due to administration of CF for 7 days was comparable to that of SFO for 14 days. Age and sex did not affect improvement of Hb value. CF is fast acting and highly effective compared with SFO for the treatment of iron deficiency anemia. The use of CF may shorten a therapeutic period for iron deficiency anemia, and CF may be feasible for reducing the hospitalization period.

Gossypol inhibits aromatase activity in cultured porcine granulosa cells

The present study investigated whether gossypol inhibited aromatase activity in cultured porcine granulosa cells. Aromatase activity was assayed by measuring (3)H-H(2)O released from [1beta-(3)H]-androstenedione. First, immature porcine granulosa cells were cultured with various doses of follicle stimulating hormone (FSH, 1 to 1000 ng/ml) for 1 to 5 d to determine optimal culture conditions for aromatase activity assay. Second, porcine granulosa cells were cultured with or without FSH in the presence or absence of gossypol. Gossypol, at 4 muM, significantly inhibited FSH-induced aromatase activity while showing no effect on basal aromatase activity. Gossypol did not inhibit cell proliferation during cell culture. These results suggest that gossypol inhibits aromatase activity by interfering with FSH induction of aromatase in cultured porcine granulosa cells.

Analysis of cytochrome P450 gene polymorphism in a lupus nephritis patient in whom tacrolimus blood concentration was markedly elevated after administration of azole antifungal agents

WHAT IS KNOWN AND OBJECTIVE

Both itraconazole (ITCZ) and voriconazole (VCZ) are potent inhibitors of cytochrome P450 (CYP) 3A, and their effects have been reported to be equal. However, ITCZ is metabolized by CYP3A, whereas VCZ is mainly metabolized by CYP2C9 and CYP2C19 and only partially by CYP3A. We experienced the case of a patient who showed a 5-fold increase in trough levels of tacrolimus (FK) level after switching from ITCZ to VCZ. Our objective is to discuss the mechanism of the increase drug-drug interaction in terms of serum concentration of the azole drugs and patient pharmacogenomics.

CASE SUMMARY

A 53-year-old woman was treated with FK (1 mg/day) for lupus nephritis. Because fungal infection was suspected, she received ITCZ (100 mg/day). When ITCZ was replaced with VCZ (400 mg/day), the blood concentration of FK increased markedly from 6·1 to 34·2 ng/mL. During coadministration with FK, the levels of ITCZ and VCZ were 135·5 ng/mL and 5·5 μg/mL, respectively, with the VCZ level around 3-fold higher than the previously reported level (1·4-1·8 μg/mL). Her CYP genotypes were CYP2C19*1/*2, CYP3A4*1/*1 and CYP3A5*3/*3.

WHAT IS NEW AND CONCLUSION

The patient was a CYP2C19 intermediate metabolizer (IM) and deficient in CYP3A5. The increase in plasma VCZ level appears to have been at least in part, associated with the CYP2C19 IM phenotype. One possible explanation for the marked increase in blood FK concentration was increased inhibition of CYP3A because of the impaired metabolism and subsequent increased plasma concentration of VCZ. This case shows that the severity of drug interactions may be influenced by metabolic gene polymorphism.

Quick-scanning x-ray absorption spectroscopy system with a servo-motor-driven channel-cut monochromator with a temporal resolution of 10 ms

We have developed a quick-scanning x-ray absorption fine structure (QXAFS) system and installed it at the recently constructed synchrotron radiation beamline BL33XU at the SPring-8. Rapid acquisition of high-quality QXAFS data was realized by combining a servo-motor-driven Si channel-cut monochromator with a tapered undulator. Two tandemly aligned monochromators with channel-cut Si(111) and Si(220) crystals covered energy ranges of 4.0-28.2 keV and 6.6-46.0 keV, respectively. The system allows the users to adjust instantly the energy ranges of scans, the starting angles of oscillations, and the frequencies. The channel-cut crystals are cooled with liquid nitrogen to enable them to withstand the high heat load from the undulator radiation. Deformation of the reflecting planes is reduced by clamping each crystal with two cooling blocks. Performance tests at the Cu K-edge demonstrated sufficiently high data quality for x-ray absorption near-edge structure and extended x-ray absorption fine-structure analyses with temporal resolutions of up to 10 and 25 ms, respectively.