Changes in Vascular Permeability and Expression of Different Angiogenic Factors Following Anti-Angiogenic Treatment in Rat Glioma

Background

Anti-angiogenic treatments of malignant tumors targeting vascular endothelial growth factor receptors (VEGFR) tyrosine kinase are being used in different early stages of clinical trials. Very recently, VEGFR tyrosine kinase inhibitor (Vetanalib, PTK787) was used in glioma patient in conjunction with chemotherapy and radiotherapy. However, changes in the tumor size, tumor vascular permeability, vascular density, expression of VEGFR2 and other angiogenic factors in response to PTK787 are not well documented. This study was to determine the changes in tumor size, vascular permeability, fractional plasma volume and expression of VEGFR2 in PTK787 treated U-251 glioma rat model by in vivo magnetic resonance imaging (MRI) and single photon emission computed tomography (SPECT). The findings were validated with histochemical and western blot studies.

Methodologies and Principal Findings

Seven days after implantation of U251 glioma cells, animals were treated with either PTK787 or vehicle-only for two weeks, and then tumor size, tumor vascular permeability transfer constant (K^trans), fractional plasma volume (fPV) and expression of VEGFR2 and other relevant angiogenic factors were assessed by in vivo MRI and SPECT (Tc-99-HYNIC-VEGF), and by immunohistochemistry and western blot analysis. Dynamic contrast-enhanced MRI (DCE-MRI) using a high molecular weight contrast agent albumin-(GdDTPA) showed significantly increased K^trans at the rim of the treated tumors compared to that of the central part of the treated as well as the untreated (vehicle treated) tumors. Size of the tumors was also increased in the treated group. Expression of VEGFR2 detected by Tc-99m-HYNIC-VEGF SPECT also showed significantly increased activity in the treated tumors. In PTK787-treated tumors, histological staining revealed increase in microvessel density in the close proximity to the tumor border. Western blot analysis indicated increased expression of VEGF, SDF-1, HIF-1α, VEGFR2, VEGFR3 and EGFR at the peripheral part of the treated tumors compared to that of central part of the treated tumors. Similar expression patters were not observed in vehicle treated tumors.

Conclusion

These findings indicate that PTK787 treatment induced over expression of VEGF as well as the Flk-1/VEGFR2 receptor tyrosine kinase, especially at the rim of the tumor, as proven by DCE-MRI, SPECT imaging, immunohistochemistry and western blot.     

Low dose Estrogen Prevents Neuronal Degeneration and Microglial Reactivity in an Acute Model of Spinal Cord Injury: Effect of Dosing,Route of Administration,and Therapy Delay

Spinal cord injury (SCI), depending on the severity of injury, leads to neurological dysfunction and paralysis. Methylprednisolone, the only currently available therapy renders limited protection in SCI. Therefore, other therapeutic agents must be tested to maximize neuroprotection and functional recovery. Previous data from our laboratory indicate that estrogen (17β-estradiol) at a high dose may attenuate multiple damaging pathways involved in SCI and improve locomotor outcome. Since use of high dose estrogen may have detrimental side effects and therefore may never be used in the clinic, the current study investigated the efficacy of this steroid hormone at very low doses in SCI. In particular, we tested the impact of dosing (1–10 μg/kg), mode of delivery (intravenous vs. osmotic pump), and delay in estrogen application (15 min–4 h post-SCI) on microgliosis and neuronal death in acute SCI in rats. Treatment with 17β-estradiol (1–10 μg/kg) significantly reduced microglial activation and also attenuated apoptosis of neurons compared to untreated SCI animals. The attenuation of cell death and inflammation by estrogen was observed regardless of mode and time of delivery following injury. These findings suggest estrogen as a potential agent for the treatment of individuals with SCI.     

In vitro plant development and root colonization of Coleus forskohlii by Piriformospora indica

The present study was conducted for optimization of in vitro substrates under aseptic conditions for interaction of Piriformospora indica with the medicinal plant Coleus forskohlii. It aims to test the effects of different substrates on P. indica colonization as well as growth parameters of the in vitro raised C. forskohlii. Interaction of in vitro C. forskohlii with root endophyte P. indica under aseptic condition resulted in increase in growth parameters in fungus colonized plants. It was observed that P. indica promoted the plant’s growth in all irrespective of substrates used for co-culture study. The growth was found inferior in liquid compared to semisolid medium as well as there was problem of hyperhydricity in liquid medium. P. indica treated in vitro plantlets were better adapted for establishment under green house compared to the non treated plants due to fungal intervention.     

Aedes hensilli as a Potential Vector of Chikungunya and Zika Viruses

An epidemic of Zika virus (ZIKV) illness that occurred in July 2007 on Yap Island in the Federated States of Micronesia prompted entomological studies to identify both the primary vector(s) involved in transmission and the ecological parameters contributing to the outbreak. Larval and pupal surveys were performed to identify the major containers serving as oviposition habitat for the likely vector(s). Adult mosquitoes were also collected by backpack aspiration, light trap, and gravid traps at select sites around the capital city. The predominant species found on the island was Aedes (Stegomyia) hensilli. No virus isolates were obtained from the adult field material collected, nor did any of the immature mosquitoes that were allowed to emerge to adulthood contain viable virus or nucleic acid. Therefore, laboratory studies of the probable vector, Ae. hensilli, were undertaken to determine the likelihood of this species serving as a vector for Zika virus and other arboviruses. Infection rates of up to 86%, 62%, and 20% and dissemination rates of 23%, 80%, and 17% for Zika, chikungunya, and dengue-2 viruses respectively, were found supporting the possibility that this species served as a vector during the Zika outbreak and that it could play a role in transmitting other medically important arboviruses.     

Novel Engineered Nanocrystalline Ultra-hydrophilic Hard Ceramic Coatings for Attachment and Growth of Bone Marrow Stromal Cells

This article has no abstract.     

An analysis of phase holdup in concurrent gas liquid upflow through packed beds using (I) drift-flux model, and (II) slip ratio

Correlations were developed to predict total and dynamic liquid holdup in terms of drift flux model, hold up ratio, and gas and liquid Reynolds numbers for the experimental data of the present study covering air-water and air-MEA systems for three different packing and a wide range of literature data. These corelations predict the present data and most of the literature data with an RMS deviation less than 0.1. The present static liquid holdup data was found to agree with the correlation due to Saez and Carbonell (1985).     

In vitro BrdUrd incorporation of colorectal tumour tissue

Abstract. This study describes a novel in vitro method for the incorporation of the thymidine analogue, bromodeoxyuridine (BrdUrd), in fresh colorectal tumour tissue. Disaggregation by pronase, collagenase and DNAse resulted in high cell yields of viable single cell suspensions, representative of the original tumour, which could be infiltrated with BrdUrd. A modified ELISA identified optimal incubation times and BrdUrd concentrations. This technique has been used in preliminary studies to investigate two important areas intrinsic in the analysis of BrdUrd colorectal cell proliferation data: 1 to determine the effects of the individual constituents of the cell culture media, in particular glutamine, on BrdUrd incorporation in suspensions of colorectal cells and 2 to examine the denaturation step. This method will have wide applicability in investigations of cell proliferation status in both normal and diseased tissue.