10 research outputs found
ChemInform Abstract: trans-2,6-, 3,6- and 4,6-Diaza-5,6,6a,7,8,12b-hexahydrobenzo[c]phenanthrene-10,11-diols as Dopamine Agonists.
No full textHuman astrocytoma U138MG cells express predominantly type-A endothelin receptor
No full textAbstractEndothelin-1 (ET-1) binding to human astrocytoma U138MG cells was time-dependent, and bound [125I]ET-1 was difficult to dissociate. The Bmax and Kd values of [125I]ET-1 binding were 70 fmol/mg and 0.07 nM, respectively. Interestingly, different from other astrocytoma cells and astrocytes, the U138MG cells expressed predominantly ETA receptor as shown by RT-PCR results and binding studies. ET-1, FR139317, BQ123, PD142893 and Ro46–2005 inhibited specific [125I]ET-1 binding with Ki values of 0.10, 0.53, 4.3, 22, and 320 nM, respectively. ETB selective ligands ET-3 and IRL1620 were much less potent. The inhibitory effects of antagonists BQ123 and PD142893 on [125I]ET-1 binding diminished following the incubation time. ET-1 binding caused a modest stimulation in phosphatidylinositol hydrolysis with an EC50 value of 24 nM. In comparison to the human U373MG cells. ET-1-induced receptor internalization in U138MG cells was less efficient with 42% of bound ET-1 internalized after 30 min of incubation. These results imply that human astrocytoma cells/astrocytes are able to express either ETA or ETB receptor under different pathophysiological conditions
Cholecystokinin (CCK) antagonists: (R)-tryptophan-based hybrid antagonists of high affinity and selectivity for CCK-A receptors
No full textCCK antagonists: Investigations of the relationship between benzotript and glutamic acid-based antagonists
No full textStock Market Integration Between the Hong Kong SAR and the People's Republic of China - the Use of a Revised 'H' Share Model and Enhanced Institutional Support
No full textPhDBilateral, multilateral and regional linkages between stock exchanges generate
increased sources of funds, investor return and product choice. Such
associations can also lower transaction costs in both initial listing and
subsequent trading, increase liquidity more generally in the secondary market
and enhance investor protection and confidence in the stability and reputation
of the market and the status of companies listed on the market. This thesis
argues that the integration of the stock markets between The Special
Administrative Region of Hong Kong ("Hong Kong") and the People's
Republic of China (CTRC) is therefore a desirable objective and investigates
how a more successful and substantial degree of integration could be achieved
in this area.
Integration, in particular, requires harmonization of laws and regulations. In
1993,H shares issued by PRC companies were first allowed to cross-list on the
Hong Kong Stock Exchange. This listing was made possible by the
introduction of a new set of legal and operational rules promulgated in both the
PRC and Hong Kong.
This thesis expounds four models of integration, the H Share Model, the
System Harmonization Model, the Mixed Harmonization and Mutual
Recognition Model, and the Full Harmonization Model and argues that H share
regulations are an effective way to further integration despite problems
inherited from the PRC's 'pre-open door' policy.
In considering other potential models, the European Union and the United
States capital market are also considered as potential models for further
integration of the PRC and Hong Kong stock markets despite the inherent
limitations of the latter model.
It is also proposed that enhanced institutional support can be used as an
effective means of accelerating the integration process. Investigating both the
feasibility and possible implementation of market integration within an
appropriate institutional framework ensures an autonomous, legal and
independent environment separate from the political realm
Functional analysis of the tomato Ve resistance locus against Verticillium wilt
No full text Verticillium dahliae, V. albo-atrum and V. longisporum are soil-borne plant pathogens that are responsible for Verticillium wilt diseases in temperate and subtropical regions. Collectively they can infect over 200 hosts, including many economically important crops. Chapter 1 is a “pathogen profile” which describes the most important aspects of the biology of the Verticillium wilt pathogens. They colonize the xylem vessels of their host plants and cause symptoms such as wilting, chlorosis, stunting, necrosis and vein clearing. Verticillium species are notoriously difficult to control as there are no fungicides available to cure plants once they are infected. Therefore, genetic resistance is the preferred method for disease control. Chapter 2 describes the functional characterization of the tomato (Solanum lycopersicum) Ve locus. This locus is responsible for resistance against race 1 strains of V. dahliae and V. albo-atrum and comprises two closely linked inversely oriented genes, Ve1 and Ve2. Both genes encode cell surface receptor proteins of the extracellular leucine-rich repeat (eLRR) receptor-like protein (RLP) class of disease resistance proteins. In chapter 2, it is demonstrated that Ve1, but not Ve2, provides resistance in tomato against race 1 but not against race 2 strains of V. dahliae and V. albo-atrum. Using virus-induced gene silencing in tomato, the signaling cascade downstream of Ve1 was shown to require both EDS1 (enhanced disease susceptibility1) and NDR1 (non-race-specific disease resistance1). In addition, also NRC1 (NB-LRR protein required for hypersensitive response-associated cell death1), ACIF (Avr9/Cf-9–induced F-box1), MEK2 (MAP/ERK kinase2), and SERK3/BAK1 (somatic embryogenesis receptor kinase 3/brassinosteroid-associated kinase 1) act as positive regulators of Ve1 in tomato. In conclusion, Ve1-mediated resistance signaling only partially overlaps with signaling mediated by Cf proteins, type members of the eLRR-RLP-class of resistance proteins. In chapter 3 an attempt to introduce Nicotiana benthamiana as a model to facilitate the study of Ve1-mediated resistance is described. Challenge of wild type plants with several race 1 and race 2 strains of V. dahliae and V. albo-atrum demonstrated that N. benthamiana is susceptible to both Verticillium species. To obtain Verticillium wilt resistant plants, N. benthamiana was engineered to express the tomato Ve1 coding sequence. However, out of thirteen transgenic lines, six showed clear phenotypic aberrancies that included severe stunting and malformed leaves when compared to wild type plants. The seven Ve1-transgenic lines that did not show any phenotypic alterations were challenged with race 1 and race 2 strains. Although the pathogenicity assays indicated that in few lines Ve1 expression temporarily reduced disease development, most lines were as susceptible as wild type parental line. In conclusion, in chapter 3 it is demonstrated that the Ve1-transgenic N. benthamiana lines could not be used to study Ve1-mediated resistance signaling. In chapter 4, the use of Arabidopsis (Arabidopsis thaliana) as model to facilitate the study of Ve1-mediated resistance is presented. To this end, tomato Ve1 was expressed in susceptible Arabidopsis plants. Upon challenge with race 1 strains of V. dahliae or V. albo-atrum, Ve1-expressing plants were found to be resistant. In contrast, Ve1-expressing plants were susceptible to race 2 strains of both V. dahliae and V. albo-atrum. Furthermore, expression of Ve1 in Arabidopsis plants did not prevent colonization by V. longisporum strains. Through Ve1-expression in Arabidopsis defense signaling mutants, it was demonstrated that signaling downstream of Ve1 is highly conserved between tomato and Arabidopsis. In previous chapters it was shown that the receptor kinase SERK3/BAK1 is required for Ve1-mediated resistance in tomato as well as in Arabidopsis. In Arabidopsis, SERK3/BAK1 belongs to a gene family consisting of five members. In chapter 5, the requirement of the different SERK family members in Ve1-mediated resistance in Arabidopsis is investigated, revealing the requirement of SERK1 and, although to a lesser extent, SERK4 for resistance. Using virus-induced gene silencing, it was subsequently shown that SERK1 is also required for Ve1-mediated resistance in tomato. In conclusion, the results of chapter 5 demonstrate that Arabidopsis can be used as model to unravel the molecular mechanisms of Ve1-mediated resistance. In chapter 6, the recognition specificity of Ve1 was further investigated by performing domain-swaps with Ve2 and expressing the chimeric Ve proteins in Arabidopsis. Various domain swaps in which eLRRs from Ve1 were replaced by those of Ve2 suggest that the region between eLRR22 and eLRR35 is required for full Ve1-mediated resistance. However, plants expressing a Ve chimera in which eLRR1 to eLRR30 of Ve1 was replaced with those of Ve2 were resistant against Verticillium. Overall, these results suggest that Ve2 may still bind the elicitor in the eLRR domain, but its C-terminal domain is not able to activate a successful defense response. Finally in Chapter 7, highlights of this thesis are discussed and placed in a broader perspective. </p
Assessing the response of T cells to "Mycobacterium tuberculosis" lipids
No full textMost vaccines used nowadays are created using inactivated or attenuated compounds
from micro-organisms. Advances in basic immunology and molecular biology opened the
gate for consequent improvement of vaccination strategies. The vast majority of successful
vaccines developed so far functions through production of specific antibodies, thus allowing
rapid eradication of the disease’s causative agent. However, intracellular bacterial pathogens
like Mycobacterium tuberculosis hide from immune attack by antibodies within cells, and
their virulence is related to their capacity to survive for prolonged times within macrophage
phagosomes by blocking lysosomal delivery and subsequent degradation. Therefore, design
of more effective vaccination strategies is needed to ensure efficient killing of this type of
pathogens. The discovery of CD1 molecules, that present lipidic antigens from the bacterial
cell wall to T cells, might be an additional step in this direction. In this dissertation, we used
chemical and biochemical approaches to identify and synthesize lipid antigens, as well as T
cell activation assays, molecular biology tools, and transgenic mice to evaluate the potential
of lipid antigens to be included in subunit vaccines.
In a first series of studies, we identified glycerol monomycolate (GroMM) as a mycobacterial
lipid antigen that activates CD1b-restricted T cells, and confirmed its immunogenicity during
the course of infection by M. tuberculosis. GroMM efficiently stimulates T cells from PPDpositive
healthy donors, but not from non-infected donors nor patients with active
tuberculosis. These data suggest that GroMM-reactive T cells are primed during infection and
may contribute to protection against pathogenic mycobacteria, rendering GroMM an
interesting candidate for further evaluation to be used in vaccination strategies.
A second series of studies dealt with a lipid antigen from M. tuberculosis previously identified in our laboratory, i.e. diacylated sulfoglycolipids (Ac2SGL). Sulfoglycolipid (SGL)
analogs were synthesized in order to study the structural constraints governing binding to
CD1b and generation of immunogenic CD1b-SGL complexes. Comparison of these analogs
sharing the same trehalose-sulfate polar head but differing in the structure of their acyl tails
showed that the number of C-methyl substituents, the configuration of the chiral centers, and
the respective localization of the two different acyl chains on the polar head are important structural elements that must be considered for the design of sulfoglycolipid analogs with
potential use as vaccine subunits.
In a third series of experiments, we began pre-clinical in vivo studies in CD1b-transgenic
mice that we have generated, using the most immunogenic synthetic SGL analog. CD1b:SGL
dimers allowed us to follow successful priming and expansion of CD1b-restricted SGLreactive
T cells after immunization. Finally, we have investigated different ways to increase
immunogenicity by facilitating lipid solubilisation and transport into antigen presenting cells
(APCs).
Altogether, the data obtained and discussed in the present dissertation go through the first
stages of a vaccine’s development, from identification of candidate antigens to pre-clinical in
vivo studies in mice. Confirmation of the protective effect of the lipid antigens described
herein will determine whether they can be considered as candidate compounds of a subunit
vaccine
Expresión inmunohistoquimica de subpoblaciones linfocitarias en la regresión tumoral, de pacientes sometidos a quimioterapia como tratamiento del tumor venéreo transmisible canino
No full textIlustraciones, gráficasspa: El tumor venéreo transmisible canino es uno de los tres canceres transmisibles observados en mamíferos, siendo un cáncer contagioso que se transmite naturalmente entre perros mediante una trasferencia alogénica de células neoplásicas vivas principalmente en el momento del coito. Se ha estimado que este tumor trasmisible surgió hace 11.000 años y a partir de ese momento empezó su viaje a colonizar el mundo, hasta el día de hoy mostrando una distribución mundial sustentada en reportes de caso en los cinco continentes. Estas células al momento de implantarse pueden evitar la respuesta inmune del hospedero escapándose de la barrera del complejo mayor de histocompatibilidad. Mostrando una actividad inmunológica diferente en sus fases de progresión y regresión. El objetivo de este estudio fue evaluar la expresión inmunohistoquímica de subpoblaciones linfocitarias en la regresión tumoral de pacientes sometidos a quimioterapia como tratamiento del tumor venéreo transmisible canino, la relación que pueda existir con la respuesta al tratamiento y la fase histopatológica en que se encuentre antes y durante la tercera semana de tratamiento. Para el presente estudio se utilizaron fragmentos de TVTC 24 caninos antes de iniciar quimioterapia con sulfato de Vincristina, igualmente se tomaron 15 fragmentos durante la tercera semana posterior inicio de tratamiento antes de la aplicación de la cuarta sesión de quimioterapia. Se realizó inmunohistoquímica para la expresión de anticuerpos CD3, CD8 y CD79 de las muestras de TVTC obtenidas. CD3 y CD8 mostraron aumento en la expresión en comparación con CD79, principalmente en los pacientes que requirieron un número más elevado de sesiones de quimioterapia, además, se observó mayor expresión de CD8 en las muestras en la fase de regresión y disminución significativa en la marcación de CD3 y CD8 durante el tratamiento sugiriendo que el uso de sulfato de vincristina puede afectar la respuesta inmunológica intratumoral del TVTC. Desde su primer reporte hace cerca de 140 años el TVTC ha despertado el interés de científicos convirtiéndolo en un modelo de estudio de comportamiento, desarrollo, inmunología y origen del cáncer en animales.eng:Canine transmissible venereal tumor is one of the three transmissible cancers
observed in mammals, being a contagious cancer that is transmitted
naturally between dogs by allogeneic cell transfer
neoplastic cells living mainly at the time of intercourse. It has been estimated that this
Transmissible tumor arose 11,000 years ago and from that moment began its
voyage to colonize the world, to this day showing a worldwide distribution
supported by case reports in the five continents. These cells at the moment
implanted, they can avoid the host's immune response by escaping from
the major histocompatibility complex barrier. Displaying an activity
different immunology in its phases of progression and regression. The goal of this
study was to evaluate the immunohistochemical expression of lymphocyte subpopulations
in tumor regression of patients undergoing chemotherapy as treatment
of the canine transmissible venereal tumor, the relationship that may exist with the response
treatment and histopathological phase before and during the
third week of treatment. For the present study, fragments of
24 canine TVTC before starting chemotherapy with Vincristine sulfate,
Likewise, 15 fragments were taken during the third week after the start of
treatment before the application of the fourth chemotherapy session. It has been made
immunohistochemistry for the expression of CD3, CD8 and CD79 antibodies from
TVTC samples obtained. CD3 and CD8 showed increased expression in
compared with CD79, mainly in patients who required a number of
higher number of chemotherapy sessions, in addition, greater expression was observed
of CD8 in the samples in the regression phase and significant decrease in the
CD3 and CD8 labeling during treatment suggesting that the use of sulfate
Vincristine may affect the intratumoral immune response to TVTC. From
its first report about 140 years ago the TVTC has aroused the interest of
scientists turning it into a model of study of behavior, development,
immunology and origin of cancer in animals.Resumen/1. Introducción/ 2. Planteamiento del problema/ 3. Justificación/ 4. Marco teórico/ 4.1Tumor venéreo trasmisible canino/ 4.2TVTC y la búsqueda de su origen/ 4.3Distribución del TVTC/ 4.4Diagnóstico del TVTC / 4.4.1 Citología/ 4.4.2 Histopatología/ 4.4.3 Reacción en Cadena de Polimerasa (PCR)/4.5 Inmunohistoquímica/ 4.6 Tratamiento/ 4.7 Respuesta inmune contra el TVTC/ 5. OBJETIVOS/ 5.1Objetivo General/ 5.2Objetivos Específicos/ 6. MATERIALES Y METODOS/ 6.1Comité de Ética/ 6.2Procedimientos y Manejo de Animales/ 6.3Diagnostico TVTC/ 6.4Colecta y procesamiento de muestras/ 6.5Análisis histopatológico/ 6.6Análisis Molecular / 6.6.1 Extracción de ADN/ 6.6.2 PCR en tiempo real cuantitativa (qPCR)/6.7Inmunohistoquímica CD3, CD8 y CD79/ 6.7.1 Validación de la marcación/ 6.8Análisis estadístico/ 7. RESULTADOS/ 7.1 Datos epidemiológicos, clínicos y respuesta al tratamiento/ 7.2 Examen citológico/ 7.3 Respuesta al tratamiento/ 7.4 Clasificación histopatológica/ 4 7.5 Análisis molecular qPCR/ 7.5.1 Detección LINE-1/c-myc/ 7.5.2 Detección CDKN2A/ 7.6 Expresión Inmunohistoquímica/ 7.6.1 Marcación porcentual CD3, CD8 y CD79/ 8. DISCUSIÓN/ 9. CONCLUSIONES/ 10.REFERENCIAS/ 11.ANEXOS.MaestríaMagister en Ciencias Veterinaria
