Thesis (Ph.D.)--York University, 2005. Graduate Programme in Biology. / Typescript. Includes bibliographical references (leaves 166-200). Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://wwwlib.umi.com/cr/yorku/fullcit?pNR11583

Thesis (Ph. D.)--Ohio State University, 2007. / Title from first page of PDF file. Includes bibliographical references (p. 137-169).

Orientador: Gisele Fabrino Machado / Banca: Valéria Marçal Felix de Lima / Banca: Flávia Lombardi Lopes / Banca: Paulo Ricardo Dell'Amerina Rocha / Banca: Monica Regina Vendrame Amarante / Resumo: A leishmaniose visceral (LV) é uma doença parasitária que apresenta distribuição mundial e que pode afetar homens e animais, sendo que o cão é considerado o principal hospedeiro da doença. Cães infectados pelo parasito Leishmania podem apresentar-se assintomáticos ou com desordens generalizadas, incluindo alterações neurológicas. Existem alguns relatos do acometimento do encéfalo durante a infecção, mas a neuropatogenia da doença não foi completamente elucidada. Há evidências do comprometimento das barreiras encefálicas e da presença do DNA do parasito no encéfalo. Os receptores tipo Toll (TLRs) são sensores do sistema imune inato capazes de detectar padrões moleculares associados aos patógenos (PAMPs), desencadeando uma resposta inflamatórias com produção de diversos mediadores inflamatórios, incluindo citocinas. Desta forma, o objetivo deste estudo foi avaliar o perfil de expressão gênica dos Tolls 1-10, assim como a produção de citocinas pró-inflamatórias TNF-α, IFN-γ, IL-1β e IL-6 no encéfalo e no baço de cães com leishmaniose visceral. No baço houve aumento de expressão gênica de TLR-5 e TLR-9, enquanto no encéfalo houve aumento de TLR-4 em uma pequena população de cães infectados. Em relação às citocinas, todas as citocinas foram detectadas nos dois tecidos avaliados, com excessão de IL-6. Nos cães infectados, TNF-α e IL-1β estavam presentes em maiores concentrações no encéfalo e no baço, respectivamente. Este estudo fornece suporte para explicar o envolvimento de TLRs ... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract:Visceral leishmaniasis (VL) is a parasitic disease that presents world distribution, affecting humans and animals. Dogs are considered the main hosts of the disease. Infected dogs with the Leishmania parasite can be asymptomatic or present generalized disorders, including neurological alterations. There are some reports of brain commitment during infection. Nevertheless, neuropathogenesis of VL is not completely elucidated. There are evidences of brain barriers breakdown and of the presence of Leishmania DNA in the brain. Toll-like receptors (TLRs) are innate immune sensors capable of detecting pathogen-associated molecular patterns (PAMPs), trigger an inflammatory response with production of several inflammatory mediators, including cytokines. Therefore, the aim of this study was to evaluate gene expression profile of TLRs1-10, along with the production of proinflammatory cytokines in both brain and spleen in dogs with VL. In spleen there was an upregulation of TLR-5 and TLR-9 while in the brain there was up-regulation of TLR- 4 in a few number of infected animals. Regarding cytokines, all cytokines were detected in both tissues, except IL-6. In the infected dogs, TNF-α and IL-1β were present at higher concentrations in the brain and spleen, respectively. This study provides support to explain the involvement of TLRs in VL and our data confirm the brain as an affected organ in this disease / Doutor

Hyperglycemia associated with diabetes has been recognized for adverse neurodegenerative effects it has on the central nervous system (CNS). However, few cerebral histopathological studies have been completed to adequately define the neuropathology of type 2 diabetes. The aim of the study was to conduct a neuropathological survey of diabetic Zucker Diabetic Sprague Dawley (ZDSD) rat brains that included a wide variety of potential pathologies. Ten ZDSD rat brains (diabetic: n=6 non-diabetic obese: n=4) were collected for neuropathological assessments. Specific measures include assessments of gray and white matter atrophy, neurodegeneration, astrocyte activation, blood brain barrier integrity, inflammation, and amyloid protein deposit. After brain sectioning, formal thionin, immunoglobulin G (IgG), glial fibrillary acidic protein (GFAP), giemsa, congo-red, and flourojade (FJ) stains were performed for analysis. Of the several neuropathological assessments, two revealed significant differences between diabetic and non-diabetic groups. Diabetic ZDSD rats had a relative decrease in the amount of white matter in the corpus callosum underlying the cingulate cortex of the brain. Secondly, higher numbers of lymphocytes were observed in the hypothalamus of the diabetic rats compared to non-diabetic rats. Enhanced expression of GFAP was not present. No measurable differences were observed in analysis of amyloid, FJ intensity levels or immunoglobulin G (IgG) extravisation into the brain. These results suggested that ZDSD rats do not exhibit neuropathology excepting white matter atrophy and increased lymphocyte infiltration into the hypothalamus, or that the duration of 6-7 month old diabetic ZDSD rats may be insufficient to support most of our hypotheses. Future work is required to determine profiles of neuropathology in longer term of diabetic ZDSD rats.

Mephenoxalone is a mild central nervous system depressant with activity resembling that of meprobamate. Since its introduction in 1961 mephenoxalone has been used as an anxiolytic and as a muscle relaxant, although the latter effect is weak. Preliminary studies on the absorption and disposition of mephenoxalone have been conducted in beagle dogs but no pharmacokinetic data from human studies have been reported, except for a single study in which the biotransformation products present in human urine were identified. Methods presently available for the determination of mephenoxalone in biological fluids lack the sensitivity, specificity and precision required for detailed pharmacokinetic studies. In this study, a rapid, sensitive, precise reverse-phase high-performance liquid chromatographic method with ultraviolet detection at 200nm was employed for the determination of mephenoxalone in biological fluids. Serum and urine samples were prepared for chromatographic analysis using simple liquid-liquid extraction techniques. The application of the assay to pharmacokinetic studies in humans is presented. After administration of a single oral dose of 400mg mephenoxalone dispersed in 150ml water to six young, healthy volunteers, the compound was rapidly absorbed with the peak concentration of 8μg/ml occurring after about 1 hour. The elimination half-life was approximately 3 hours. The drug was extensively metabolized with only about 1 percent of the administered dose being excreted unchanged in the urine after 24 hours. The bioavailability of a newly developed mephenoxalone-containing tablet was also investigated. The drug was absorbed more rapidly from the tablet than from the dispersed dose. This was attributed to a shorter in vivo dissolution time on the basis of in vitro tests, but this effect is not expected to be clinically significant. In addition, two human urinary metabolites of mephenoxalone were identified as unconjugated hydroxylated derivatives using thermospray HPLC-mass spectrometry. The plasma protein-binding properties of mephenoxalone were also investigated.

abstract: Neurodegenerative diseases such as Alzheimer’s disease, Parkinson’s disease, or amyotrophic lateral sclerosis are defined by the loss of several types of neurons and glial cells within the central nervous system (CNS). Combatting these diseases requires a robust population of relevant cell types that can be employed in cell therapies, drug screening, or patient specific disease modeling. Human induced pluripotent stem cells (hiPSC)-derived neural progenitor cells (hNPCs) have the ability to self-renew indefinitely and differentiate into the various neuronal and glial cell types of the CNS. In order to realize the potential of hNPCs, it is necessary to develop a xeno-free scalable platform for effective expansion and differentiation. Previous work in the Brafman lab led to the engineering of a chemically defined substrate—vitronectin derived peptide (VDP), which allows for the long-term expansion and differentiation of hNPCs. In this work, we use this substrate as the basis for a microcarrier (MC)-based suspension culture system. Several independently derived hNPC lines were cultured on MCs for multiple passages as well as efficiently differentiated to neurons. Finally, this MC-based system was used in conjunction with a low shear rotating wall vessel (RWV) bioreactor for the integrated, large-scale expansion and neuronal differentiation of hNPCs. Finally, VDP was shown to support the differentiation of hNPCs into functional astrocytes. Overall, this fully defined and scalable biomanufacturing system will facilitate the generation of hNPCs and their derivatives in quantities necessary for basic and translational applications. / Dissertation/Thesis / Masters Thesis Biomedical Engineering 2018

No description available.

Thesis (Master's Diploma(Technology (Medical Technology))-- Cape Technikon, 1997 / Meningitis in children is a common and serious disease. Bacterial and tuberculous meningitis often lead to neurological complications. A sensitive marker to predict brain damage in children with meningitis could be of great importance. Frithz F et aI, 1982 suggested that increased adenylate kinase values could indeed be used as a marker for brain damage. Adenylate kinase (AK) is an enzyme present in brain tissue. Low concentrations are present in normal cerebrospinal fluid (CSF) « 1 uti). Increased concentrations were found in cases of ischemic brain damage (Frithz et aI, 1982), malignant brain tumours (Ronquist G et aI, 1977) and bacterial meningitis. As AK has a low molecular weight (22,00 Daltons), in comparison to other kinases (40,000 Daltons) it is one of the first enzymes that can be detected in the CSF after brain damage and it can thus be used as a reliable marker for brain cell damage. The aim of this study was to quantify the AK values in CSF of children with bacterial and tuberculous meningitis and to evaluate their use to predict the neurological outcome in children with bacterial and tuberculous meningitis. Eighty eight children with tuberculous meningitis (TBM) and thirty three children with bacterial meningitis were included in the study. Sixty children with suspected meningitis but who were later diagnosed with urinary tract infections, gasto-enteritis, bronchitis, febrile convulsions or other non-neurological infections were used as controls. The results showed raised AK values in the CSF of children with bacterial- and TB meningitis. There was a statistically significant difference of AK values between stage III and II TBM AK values in patients at week 1 after diagnosis (p=0,03). There was also a statistically significant correlation between CSF AK values and lactate concentrations (P=0,001) which reflected hypoxic brain metabolism. Although AK values did not always correlate directly with the patients’ clinical outcome, there is proof that increased AK values in CSF can be used to predict neurological outcome.

The permeation of drugs across the blood-brain barrier (BBB) is a prerequisite for central nervous system (CNS) drug penetration. The BBB, possessing efflux transporters and tight junctions, limits drug penetration to the brain. Consequently, the discovery of novel drugs to treat CNS diseases remains problematic and is lagging behind other therapeutic areas. In vitro assays have progressed understanding of the factors that govern brain penetration. Central nervous system drug penetration is now thought to be modulated by three main processes, namely BBB permeability, active transport at the BBB and drug binding in blood and brain tissue. A more integrated approach to CNS drug discovery programmes is emerging which encompasses these processes in order to examine the rate and extent of drug brain penetration across species and improve predictions in human.A primary porcine in vitro BBB model was developed and characterised for the prediction of CNS drug permeability in vivo. Characterisation confirmed that the model exhibited physiologically realistic cell architecture, the formation of tight junction protein complexes, transcellular electrical resistance consistently >2000 Ω.cm2, functional expression the P-gp efflux transporter and ?-glutamyl transpeptidase and alkaline phosphatase activities.Transport of 12 centrally acting test drugs was investigated across four in vitro BBB models in order make comparisons between models and to generate in vitro permeability and efflux measurements. Blood-brain barrier permeability and active efflux processes are two major influences on the rate of drug penetration across the BBB. Species differences in fublood and fubrain, two prime influences on the extent of drug penetration, were investigated using equilibrium dialysis. Fraction unbound in brain was shown to be comparable across species suggesting that species differences in brain penetration could be due to variation in fublood for drugs that cross the BBB by passive diffusion, and/or species differences in transporter characteristics for drugs that are subject to active transport processes at the BBB. An in-house hybrid-PBPK rat CNS model was used to predict calculated rat Kp,uu using in vitro permeability, efflux, fublood and fubrain parameters generated during this work. The predicted Kp,uu generated using the rat CNS hybrid-PBPK model were within 3-fold of calculated Kp,uu. The rat CNS hybrid-PBPK model has potential use, as a tool for drug discovery scientists to aid the prediction of the extent of drug penetration in the early stages of drug discovery.This work has demonstrated that in vitro permeability and unbound drug fraction can be used to predict CNS drug penetration.

Doctor Pharmaceuticae - DPharm / The central nervous system (CNS), consisting of the brain and the spinal cord, is responsible for integrating sensory information and influencing most bodily functions . The CNS is protected from toxic and pathogenic agents in the blood by permeability barrier mechanisms. These barrier mechanisms, specifically the blood brain barrier (BBB) presents a challenge for the discovery of CNS active drugs as it is requirement for these drugs to permeate the BBB to reach their target site in the CNS. The conventional processes of drug design and discovery from natural products are time consuming, tedious, expensive and have a high failure rate. It has been reported from various studies that the use of computational modelling and simulations in drug design and discovery is less costly and less time-consuming with a greater chance of success than the conventional processes. The process of drug discovery and design can, therefore, be easily carried out using proven computer models, software, and web-based tools . / 2023