Impact of culture on public relations practices in Singapore : a study of four organizations

This study attempts to identify and analyze the factors that affect the public relation practices in Singapore.​Master of Mass Communicatio

Study on Chinese, Malay and Tamil Blogospheres in Singapore

10.25818/1cy0-37tg1-110IPS Exchange Series (Institute of Policy Studies

In Vivo Quantitative Microcomputed Tomographic Analysis of Vasculature and Organs in a Normal and Diseased Mouse Model.

Non-bone in vivo micro-CT imaging has many potential applications for preclinical evaluation. Specifically, the in vivo quantification of changes in the vascular network and organ morphology in small animals, associated with the emergence and progression of diseases like bone fracture, inflammation and cancer, would be critical to the development and evaluation of new therapies for the same. However, there are few published papers describing the in vivo vascular imaging in small animals, due to technical challenges, such as low image quality and low vessel contrast in surrounding tissues. These studies have primarily focused on lung, cardiovascular and brain imaging. In vivo vascular imaging of mouse hind limbs has not been reported. We have developed an in vivo CT imaging technique to visualize and quantify vasculature and organ structure in disease models, with the goal of improved quality images. With 1-2 minutes scanning by a high speed in vivo micro-CT scanner (Quantum CT), and injection of a highly efficient contrast agent (Exitron nano 12000), vasculature and organ structure were semi-automatically segmented and quantified via image analysis software (Analyze). Vessels of the head and hind limbs, and organs like the heart, liver, kidneys and spleen were visualized and segmented from density maps. In a mouse model of bone metastasis, neoangiogenesis was observed, and associated changes to vessel morphology were computed, along with associated enlargement of the spleen. The in vivo CT image quality, voxel size down to 20 μm, is sufficient to visualize and quantify mouse vascular morphology. With this technique, in vivo vascular monitoring becomes feasible for the preclinical evaluation of small animal disease models

The emergence and/or progression of diseases may be monitored using μCT.

<p>In this case, μCT was used to visualize the increase in spleen volume in mice with bone cancer, 1 day after administration of contrast agent (FOV: 30mm×30mm; 2 min scan). (A) Mouse spleen before cancer agent injection. (B) Mouse spleen 5 weeks after cancer agent injection.</p

HCK induces macrophage activation to promote renal inflammation and fibrosis via suppression of autophagy

Abstract Renal inflammation and fibrosis are the common pathways leading to progressive chronic kidney disease (CKD). We previously identified hematopoietic cell kinase (HCK) as upregulated in human chronic allograft injury promoting kidney fibrosis; however, the cellular source and molecular mechanisms are unclear. Here, using immunostaining and single cell sequencing data, we show that HCK expression is highly enriched in pro-inflammatory macrophages in diseased kidneys. HCK-knockout (KO) or HCK-inhibitor decreases macrophage M1-like pro-inflammatory polarization, proliferation, and migration in RAW264.7 cells and bone marrow-derived macrophages (BMDM). We identify an interaction between HCK and ATG2A and CBL, two autophagy-related proteins, inhibiting autophagy flux in macrophages. In vivo, both global or myeloid cell specific HCK-KO attenuates renal inflammation and fibrosis with reduces macrophage numbers, pro-inflammatory polarization and migration into unilateral ureteral obstruction (UUO) kidneys and unilateral ischemia reperfusion injury (IRI) models. Finally, we developed a selective boron containing HCK inhibitor which can reduce macrophage pro-inflammatory activity, proliferation, and migration in vitro, and attenuate kidney fibrosis in the UUO mice. The current study elucidates mechanisms downstream of HCK regulating macrophage activation and polarization via autophagy in CKD and identifies that selective HCK inhibitors could be potentially developed as a new therapy for renal fibrosis

Vasculature in individual organs were quantified (FOV: 20mm×20mm; 4 min scan).

<p>The liver and the the kidneys, were viewed along with their vasculature. Top row: 3D volume-rendered images of the liver and kidney. Middle row: 3D volume-rendered images of just the liver. Bottom row: 3D volume-rendered images of just the kidney.</p

Organ volume, morphology and vessel distribution were quantified using <i>in vivo</i> μCT.

<p>Top row: The coronal view of the various vessels and organs in the mouse. Bottom row: The sagittal view of the various vessels and organs in the mouse. (FOV: 30mm×30mm; 2 min scan).</p

Adjusting the threshold allowed for the imaging of several vasculature and organ structures in a live mouse (FOV: 30mm×30mm; 2 min scan).

<p>The colored lines represent the orientation (plane) and specific location where a particular cross-sectional slice has been taken. The green line represents the sagittal plane, the red line represents the transverse plane, and the blue line represents the coronal plane. (A) A 3D volume-rendered image at a high threshold (350 Hounsfield Units (HU)) allowed visualization of the main vessel, bone, and spleen. (B) A 3D volume-rendered image at a low threshold (150 Hounsfield Units (HU)) allowed visualization of small vessels, liver, and kidneys. (C) The density maps used to create the 3D volume-rendered images (left to right—transverse, coronal and sagittal planes).</p

Vasculature can be imaged down to a 20 μm voxel size.

<p>(A) Density map of a mouse heart (FOV: 30mm×30mm; 2 min scan). (B) 3D volume-rendered image of a mouse heart (FOV: 30mm×30mm; 2 min scan). (C) 3D volume-rendered image of vasculature surrounding mouse head structures. The superficial temporal vein and posterior facial vein can be viewed in great detail in these images (FOV: 20mm×20mm; 2 min scan). (D) 3D volume-rendered image of vasculature surrounding mouse hip/hind limbs, including the left and right femoral artieries and caudal femoral artery (FOV: 20mm×20mm; 2 min scan).</p

Organ Volume and Percent Vascular Volume.

<p>Organ Volume and Percent Vascular Volume.</p