Role of GDNF and its Cross-Talk with Other Growth Factors in the Dopaminergic System

Parkinson´s Disease (PD) is a neurodegenerative movement disorder resulting from loss of dopaminergic (DA) neurons in substantia nigra (SN). Possible causative treatment strategies for PD include neurotrophic factors, which protect and in some cases restore the function of dopaminergic neurons. Glial cell line-derived neurotrophic factor (GDNF) family of neurotrophic factors have been to date the most promising candidates for treatment of PD, demonstrating both neuroprotective and neurorestorative properties. We have investigated the role of GDNF in the rodent dopaminergic system and its possible crosstalk with other growth factors. We characterized the GDNF-induced gene expression changes by DNA microarray analysis in different neuronal systems, including in vitro cultured Neuro2A cells treated with GDNF, as well as midbrains from GDNF heterozygous (Hz) knockout mice. These microarray experiments, resulted in the identification of GDNF-induced genes, which were also confirmed by other methods. Further analysis of the dopaminergic system of GDNF Hz mice demonstrated about 40% reduction in GDNF levels, revealed increased intracellular dopamine concentrations and FosB/DeltaFosB expression in striatal areas. These animals did not show any significant changes in behavioural analysis of acute and repeated cocaine administration on locomotor activity, nor did they exhibit any changes in dopamine output following treatment with acute cocaine. We further analysed the significance of GDNF receptor RET signalling in dopaminergic system of MEN2B knock-in animals with constitutively active Ret. The MEN2B animals showed a robust increase in extracellular dopamine and its metabolite levels in striatum, increased tyrosine hydroxylase (TH) and dopamine transporter (DAT) protein levels by immunohistochemical staining and Western blotting, as well as increased Th mRNA levels in SN. MEN2B mice had increased number of DA neurons in SN by about 25% and they also exhibited increased sensitivity to the stimulatory effects of cocaine. We also developed a semi-throughput in vitro micro-island assay for the quantification of neuronal survival and TH levels by computer-assisted methodology from limited amounts of tissue. This assay can be applied for the initial screening for dopaminotrophic molecules, as well as chemical drug library screening. It is applicable to any neuronal system for the screening of neurotrophic molecules. Since our microarray experiments revealed possible GDNF-VEGF-C crosstalk we further concentrated on studying the neurotrophic effects of VEGF-C. We showed that VEGF-C acts as a neurotrophic molecule for the DA neurons both in vitro and in vivo, however without additive effect when used together with GDNF. The neuroprotective effect for VEGF-C in vivo in rat 6-OHDA model of PD was demonstrated. The possible signalling mechanisms of VEGF-C in the nervous system were investigated - infusion of VEGF-C to rat brain induced ERK activation, however no direct activation of RET signalling in vitro was found. VEGF-C treatment of rat striatum lead to up-regulation of VEGFR-1-3, indicating that VEGF-C can regulate the expression level of its own receptor. VEGF-C dopaminotrophic activity in vivo was further supported by increased vascular tissue in the neuroprotection experiments.

Effective drug dosage design for treatment of infectious diseases using dynamic inversion

A generic nonlinear mathematical model describing the human immunological dynamics is used to design an effective automatic drug administration scheme. Even though the model describes the effects of various drugs on the dynamic system, this work is confined to the drugs that kill the invading pathogen and heal the affected organ. From a system theoretic point of view, the drug inputs can be interpreted as control inputs, which can be designed based on control theoretic concepts. The controller is designed based on the principle of dynamic inversion and is found to be effective in curing the �nominal model patient� by killing the invading microbes and healing the damaged organ. A major advantage of this technique is that it leads to a closed-form state feedback form of control. It is also proved from a rigorous mathematical analysis that the internal dynamics of the system remains stable when the proposed controller is applied. A robustness study is also carried out for testing the effectiveness of the drug administration scheme for parameter uncertainties. It is observed from simulation studies that the technique has adequate robustness for many �realistic model patients� having off-nominal parameter values as well.

Effect of chronic administration of Tamoxifen on fertility in male bonnet monkeys (Macaca radiata)

Administration of Tamoxifen via the Alzet pump at a rate of 50 mu g hr(-1) for 90 days in the adult male bonnet monkeys Macaca radiata had no effect on the serum testosterone concentration determined at 10 AM and 10 PM as well as total sperm count determined at 15-day intervals over a period of 260 days. However, a significant reduction in sperm motility was observed beyond 90 days up until the 225th day. Breeding studies conducted from day 90 to 260 revealed that these males were infertile.

Integrating CDS/ISIS Databases with Greenstone Digital Library Software (GSDL)

CDS/ISIS is an advanced non-numerical information storage and retrieval software developed by UNESCO since 1985 to satisfy the need expressed by many institutions, especially in developing countries, to be able to streamline their information processing activities by using modern (and relatively inexpensive) technologies [1]. CDS/ISIS is available for MS-DOS, Windows and Unix operating system platforms. The formatting language of CDS/ISIS is one of its several strengths. It is not only used for formatting records for display but is also used for creating customized indexes. CDS/ISIS by itself does not facilitate in publishing its databases on the Internet nor does it facilitate in publishing on CD-ROMs. However, numbers of open source tools are now available, which enables in publishing CDS/ISIS databases on the Internet and also on CD-ROMs. In this paper, we have discussed the ways and means of integrating CDS/ISIS databases with GSDL, an open source digital library (DL) software.

Novel Levamisole Derivative Induces Extrinsic Pathway of Apoptosis in Cancer Cells and Inhibits Tumor Progression in Mice

Background: Levamisole, an imidazo(2,1-b) thiazole derivative, has been reported to be a potential antitumor agent. In the present study, we have investigated the mechanism of action of one of the recently identified analogues, 4a (2-benzyl-6-(4'-fluorophenyl)-5-thiocyanato-imidazo2,1-b]1,3,4]thi adiazole). Materials and Methods: ROS production and expression of various apoptotic proteins were measured following 4a treatment in leukemia cell lines. Tumor animal models were used to evaluate the effect of 4a in comparison with Levamisole on progression of breast adenocarcinoma and survival. Immunohistochemistry and western blotting studies were performed to understand the mechanism of 4a action both ex vivo and in vivo. Results: We have determined the IC50 value of 4a in many leukemic and breast cancer cell lines and found CEM cells most sensitive (IC50 5 mu M). Results showed that 4a treatment leads to the accumulation of ROS. Western blot analysis showed upregulation of pro-apoptotic proteins t-BID and BAX, upon treatment with 4a. Besides, dose-dependent activation of p53 along with FAS, FAS-L, and cleavage of CASPASE-8 suggest that it induces death receptor mediated apoptotic pathway in CEM cells. More importantly, we observed a reduction in tumor growth and significant increase in survival upon oral administration of 4a (20 mg/kg, six doses) in mice. In comparison, 4a was found to be more potent than its parental analogue Levamisole based on both ex vivo and in vivo studies. Further, immunohistochemistry and western blotting studies indicate that 4a treatment led to abrogation of tumor cell proliferation and activation of apoptosis by the extrinsic pathway even in animal models. Conclusion: Thus, our results suggest that 4a could be used as a potent chemotherapeutic agent.