RUNX1 meets MLL: epigenetic regulation of hematopoiesis by two leukemia genes

A broad range of human leukemias carries RUNX1 and MLL genetic alterations. Despite such widespread involvements, the relationship between RUNX1 and MLL has never been appreciated. Recently, we showed that RUNX1 physically and functionally interacts with MLL, thereby regulating the epigenetic status of critical cis-regulatory elements for hematopoietic genes. This newly unveiled interaction between the two most prevalent leukemia genes has solved a long-standing conundrum: leukemia-associated RUNX1 N-terminal point mutants that exhibit no obvious functional abnormalities in classical assays for the assessment of transcriptional activities. These mutants turned out to be defective in MLL interaction and subsequent epigenetic modifications that can be examined by the histone-modification status of cis-regulatory elements in the target genes. RUNX1/MLL binding confirms the importance of RUNX1 function as an epigenetic regulator. Recent studies employing next-generation sequencing on human hematological malignancies identified a plethora of mutations in epigenetic regulator genes. These new findings would enhance our understanding on the mechanistic basis for leukemia development and may provide a novel direction for therapeutic applications. This review summarizes the current knowledge about the epigenetic regulation of normal and malignant hematopoiesis by RUNX1 and MLL.

GW501516 acts as an efficient PPARα activator in the mouse liver

The peroxisome proliferator-activated receptor (PPAR) subtype specificity of GW501516, a well-known PPARδ-specific agonist, was studied by examining its effects on the expression of endogenous genes in primary hepatocytes and the liver of wild-type and PPARα-null mice. GW501516, like the PPARα-specific agonist Wy14,643, induced the expression of several PPAR target genes in a dose-dependent manner but this action was mostly absent in the cells and liver of PPARα-null mice. Results indicated that GW501516 acts as an efficient PPARα activator in the mouse liver.

Simultaneous assay of activated platelet count and platelet-activating capacity by P-selectin detection using K2-EDTA-treated whole blood for antiplatelet agents

INTRODUCTION

It is well recognized that examinations of activated platelets (aPLTs) and platelet-activating capacity are very important to observe and prevent embolic diseases (events) such as ischemic stroke and myocardial infarction. Previously, we reported an appropriate measurement technique of aPLT for clinical assay. In this paper, we investigated stable conditions for measurement of activating capacity of platelets.

METHODS

Blood samples were taken from healthy volunteers using anticoagulants of 2K-EDTA, sodium citrate and heparin, and platelets were stimulated with adenosine diphosphate (ADP) or collagen. We demonstrated platelet-activating capacity by detection of scattering light, absorbance, microscopic observation, and P-selectin (CD62P) expression. We also performed basic experiments in seven healthy volunteers to test the clinical application of these assays with monitoring aspirin therapy.

RESULTS

We judged that samples of whole blood with 2K-EDTA were suitable for CD62P expression assay as functional assessments of platelet activity, because platelets treated with anticoagulants such as sodium citrate and heparin were extremely damaged after stimulation, and it was difficult to measure the CD62P expression by flow cytometry. For optimal results, samples should be tested within 1 h after the drawing of blood and stimulated with ADP or collagen for 10 min. The CD62P-positive platelet value of blood from volunteers who had taken aspirin was decreased, and platelet activation was inhibited as well.

CONCLUSION

The simultaneous assay of aPLT and platelet-activating capacity by CD62P detection using whole blood treated with the K2-EDTA anticoagulant was useful for the monitoring of antiplatelet drugs.

Fine needle aspiration using forward-viewing endoscopic ultrasonography

BACKGROUND AND STUDY AIM

A prototype forward-viewing instrument has been developed for therapeutic endoscopic ultrasound (EUS)-guided fine needle aspiration (FNA). We had the opportunity to use this forward-viewing echo endoscope and to study its clinical usefulness, mainly for diagnostic EUS-FNA.

PATIENTS AND METHODS

The prototype forward-viewing echo endoscope was used for 15 months between November 2006 and March 2010, in a study group comprising 47 consecutive patients. Diagnostic EUS-FNA was done in 38 patients and the diagnostic accuracy of the forward-viewing device was compared with that from an oblique-viewing echo endoscope in reference patients who were matched by disease and puncture route. Therapeutic EUS was done in nine patients (pseudocyst drainage in six; celiac ganglia neurolysis, biliary drainage, and pancreatic duct drainage in one each).

RESULTS

Diagnostic EUS-FNA provided a correct diagnosis in 97.4 % (37/38 patients), which was not significantly different from the 94.7 % (36/38) in the reference patients. Lesions considered difficult to access with an oblique-viewing scope, such as those located at the fornix, or the head of the pancreas, or associated with strictures, were easily punctured, as were those located at the body or tail of the pancreas or at the porta hepatis. Treatment was successful in all nine patients who underwent therapeutic EUS procedures. None of the 47 patients had any complications.

CONCLUSIONS

A forward-viewing echo endoscope that allows target sites to be punctured more perpendicularly with minimal effort, can be used for diagnostic EUS-FNA and this may be advantageous, depending on the site of target lesions.

Transgenic rabbits expressing human lipoprotein lipase

To study the functions of lipoprotein lipase (LPL) in lipid and lipoprotein metabolism and the relationship between LPL and atherosclerosis, we generated transgenic rabbits expressing the human LPL gene. A total of 4045 Japanese whiterabbit embryos were microinjected with a 3.8-kb SalI/HindIII fragment containing the chicken beta-actin promoter, human LPL cDNA and rabbit beta-globin with poly (A) signals, and then transplanted into 116 recipient rabbits. Of the 166 pups born, six pups were transgenic as confirmed by Southern blot analysis. ANorthern blot analysis revealed that human LPL was expressed by a number of tissues including the heart, kidney, adrenal gland and intestine. One transgenic rabbit showed up to 3-foldincreased LPL activity in post-heparin plasma compared to thatin nontransgenic rabbits. Human LPL expression in various tissues of transgenic rabbits was further elucidated by in situ hybridization and immunostaining. Since rabbits are superior to mice as a model of atherosclerosis, this transgenicrabbit model should provide a valuable tool for the study of LPL in lipid metabolism and atherosclerosis.

Unusual radiographic appearance of ossifying fibroma in the left mandibular angle

Ossifying fibroma is usually a unilocular lesion with a well-defined, thinly corticated margin radiographically, although various patterns have been noted. The patient was a 27-year-old woman with a painless radiolucent lesion demonstrated on panoramic radiography to involve the root-apex area of the left lower second and third molars. Radiographically, the lesion had some features of a benign tumour, such as an odontogenic myxoma. However, the deep invaginations towards the interalveolar septa suggested a simple bone cyst, whereas the irregular margin and lack of expansion or mandibular canal displacement were consistent with a malignant lesion. A hard tissue component was confirmed only by soft-tissue mode CT. Although this lesion was histopathologically diagnosed as ossifying fibroma, the conflicting imaging findings were challenging and very intriguing.

Three-dimensional reconstruction of a fibro-osseous lesion using binary images transformed from histopathological images

The aim of this report was to introduce a new method of three-dimensional (3D) reconstruction for fibro-osseous lesions (FOLs) using binary images transformed from histopathological images and to describe its usefulness. A sample of multiconfluent FOL was used (one of the five types of FOL according to a radiographic classification) which was diagnosed histopathologically as ossifying fibroma. Approximately 30 pathological images were assembled into a composite image of the slide using Tiling Boutique software version 3 for Windows (Sanyo Electric, Osaka, Japan). The tiling images were transformed into 8-bit scale images and then into binary images using ImageJ software ver.1.37 (National Institutes of Health, Bethesda, MD). These images were used for 3D reconstruction using ImageJ software. Images were loaded at the same matrix size and were reconstructed into layers of two-dimensional image stacks, adjusted so that contiguous images were aligned based on their centre points, and arranged with long axes horizontal. 3D findings aided the visual understanding of morphological features in the lesion. The 3D reconstruction can be displayed with arbitrary rotation. In this case, the 3D reconstruction, using Real Image software version 4.01 for Windows (KGT, Tokyo, Japan), was created from an arbitrary section. This allowed us to determine the pattern of calcification between groups of connected osteoids and to compare the internal structure of such lesions that are not visible on histopathological findings. Differentiation of features was even more pronounced with a two colour display indicating fibrous connective tissue and osteoid tissue. A 3D reconstruction of a multiconfluent ossifying fibroma was created using binary images transformed from histopathological images. The quality of the images depends above all on the functionality of the image-processing software. Comparison of each pattern of FOL might allow more simple assessment of the morphological features of FOLs.

Development of breed identification markers based on a bovine 50K SNP array

In Japan, Japanese Black and Holstein cattle are appreciated as popular sources of meat, and imported beef from Australia and the United States is also in demand in the meat industry. Since the BSE outbreak, the problem of false sales has arisen: imported beef has sometimes been mislabeled as domestic beef due to consumer concerns. A method is needed to correctly discriminate between Japanese and imported cattle for food safety. The objective of this study was to develop breed discrimination markers between Japanese and US cattle using a 50K SNP array. As a result, five US-specific markers (BISNP7, BISNP15, BISNP21, BISNP23, and BISNP26) were developed with allelic frequencies that ranged from 0.102 (BISNP15) to 0.250 (BISNP7) and averaged 0.184. The combined use of the five markers would permit discrimination between Japanese and US cattle with a probability of identification of 0.858. This result indicates the potential of the bovine 50K SNP array as a powerful tool for developing breed identification markers. These markers would contribute to the prevention of falsified beef displays in Japan.

Central odontogenic fibroma with osteoid formation showing atypical radiographic appearance

We recently encountered an interesting tumour, containing both a diffuse sclerotic border and calcified bodies, which was eventually diagnosed as a central odontogenic fibroma. The patient was a 40-year-old man with a painless radiolucent area in the crown area of the unerupted left lower third molar shown by panoramic radiography. Clinically, the lesion was thought to represent an odontogenic tumour involving a calcified body, i.e. calcifying cystic odontogenic tumour, calcifying epithelial odontogenic tumour or ossifying fibroma. Diagnosis by radiographic findings was extremely difficult.

Relationship between period of survival and clinicopathological characteristics in patients with colorectal liver metastasis

AIM

Cancer death in the early period after hepatectomy still occurs in patients with colorectal liver metastasis (CLM). We examined the relationship between clinicopathological parameters and survival periods in 130 CLM patients who underwent hepatectomy.

PATIENTS/METHODS

Patients were divided into four groups: Group 1 (5-year survivors without tumor relapse), Group 2 (survivors at 2-5 years), Group 3 (cancer death at 2-5 years), and Group 4 (cancer death within 2 years).

RESULTS

A short surgical margin was frequent in Group 4 compared to Group 1 (31 vs. 78%, P<0.05). Primary node-positive status, absence of fibrous pseudo-capsular formation, higher Clinical Risk Score, and tumor recurrence within 12 months were frequent in Group 4 (P<0.05). Multivariate analysis revealed a short surgical margin (HR; 3.5) and early tumor relapse (HR; 5.9) as independently significant related parameters (P<0.05).

CONCLUSIONS

Sufficient surgical margins and careful follow-up for early tumor relapse may be important for improving postoperative outcomes for CLM patients.

Correlation between histopathological image and radiographic image pattern in fibro-osseous lesions in relation to bone complexity and distribution

OBJECTIVES

This study examined correlations between radiographic patterns and the shape of osteoid tissue formations, as determined histopathologically.

METHODS

20 cases of fibro-osseous lesions were investigated, comprising 5 radiographic patterns: focal (n = 3), target (n = 6), lucent (n = 4), calcification (n = 3) and multiconfluent (n = 4). Histopathological images in the central area of a full-section specimen were transformed into binary images and then into 8-bit scale images. Bone complexity and density of bone distribution were calculated and compared between patterns.

RESULTS

Bone complexity score was 7384.64 for lucent, 2029.85 for focal, 2713.40 for multiconfluent, 8388.63 for calcification and 1364.27 for target pattern. The results could be broadly separated into two types: small (target, focal and multiconfluent patterns), and large (lucent and calcification patterns). Density of bone distribution was relatively low in all areas for lucent and calcification patterns, and high for focal, multiconfluent and target patterns. No significant differences in bone complexity or density of bone distribution were seen between individual patterns.

CONCLUSIONS

Correlations appear to exist between image patterns from radiography and the shape of osteoid tissue on histopathology, but reorganization of the five patterns may be warranted.

Effects of acute exercise on visual reaction time

We examined the effects of acute exercise on reaction time to visual stimuli presented in the central portion and periphery of the visual field. Twelve participants performed reaction time tasks at rest and during cycling at 65 % peak oxygen uptake in two visual conditions. We used circular black-and-white checkerboard patterns as visual stimuli. The participants were asked to respond as quickly as possible to pattern reversal of the visual stimulus by releasing a response button. Reaction time was fractionated into Premotor time and Motor time. Premotor time in the peripheral condition significantly increased (p < 0.025) during exercise (mean +/- SE; 195.9 +/- 7.9 ms) from that at rest (183.7 +/- 6.8 ms). Premotor time in the central condition did not differ between at rest (185.3 +/- 7.6 ms) and during exercise (188.4 +/- 6.6 ms). These data suggest that the ability to respond to visual stimuli presented in the periphery of the visual field is vulnerable to moderate to severe exercise, as compared with the ability to respond to visual stimuli presented in the central portion of the visual field. An exercise-induced increase in arousal level and a consequent narrowing of attentional focus would explain the present results.

Usefulness of cone beam computed tomography for odontogenic myxoma

A case of odontogenic myxoma is reported as showing a cyst-like pattern with a partially thick but vague and unclear radiopaque border between the left mandibular second premolar and first molar on rotational panoramic radiography. Internal structure of the lesion displayed radiolucency with a sparse and coarse trabecular pattern. No expansion of bucco-lingual cortical bone was apparent. The radiographic pattern of odontogenic myxoma did not resemble a tennis racket-like or straight, curved and coarse septal appearance on panoramic radiography, but characteristic findings were noted on cone beam CT. Cone beam CT may prove extremely useful in clarifying detailed internal structure and the state of margins.