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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

The role of micro-organisms in the production of semiochemicals in the interdigital secretion of the bontebok, Damaliscus pygargus pygargus

Scott, Gary Terri 03 1900 (has links)
Thesis (MSc)--Stellenbosch University, 2004. / ENGLISH ABSTRACT: Bontebok, Damaliscus pygargus pygargus, formerly classified as D. dorcas dorcas, are territorial animals with interdigital glands between the toes of the forelegs. Males regularly defecate on dung heaps, on which they often lie, to communicate with other members of their species. They also communicate by means of visual displays, scent marking and occasionally with scraping or pawing of dung heaps. It is assumed that scent marking with the interdigital secretion serves to define territories frequented by these antelope. These glands secrete a complex mixture of volatile and non-volatile compounds and the volatile compounds in the secretion serve as a chemical signal for other bontebok. It has been suggested that the interdigital secretion is not produced in its final composition by the interdigital gland alone, but that microbial activity is responsible for many of the compounds present in the secretion. In general, many compounds can be attributed to the by-products of microbial hydrolysis of triglycerides, a common characteristic of sebum. It is well documented that micro-organisms inhabit the deep recesses of sebaceous glands and the presence of micro-organisms has been found to be consistent in all antelope exocrine glandular areas. This study involved the chemical characterisation of the volatile metabolites produced in vitro by micro-organisms from the interdigital cavity of the bontebok. Various comparative studies were made, one of which was comparison of the metabolites produced by the individual microbial species as well as the total community of bacteria incubated in different media. A comparison of the compounds identified in the interdigital secretion and the metabolites produced by the micro-organisms in the different media was also made. The volatile metabolite extracts of the individual bacterial species and of the total community were chemically characterised by low-resolution gas chromatography-mass spectroscopy. Classes of compounds identified from the volatile metabolite extracts include: • Acids - Aliphatic (saturated and unsaturated) • Alcohols - Aliphatic (saturated and unsaturated) • Aldehydes - Aliphatic (saturated and unsaturated) • Aromatic compounds • Ketones - Aliphatic (saturated and unsaturated) • Pyrazines • Dimethyldisulphide • Squalene and cholesterol Several qualitative differences were found between the compounds identified in the volatile metabolite extracts of the micro-organisms when incubated in tryptic soy broth (TSB) and minimal salt medium (MSM). In particular, when the microbes were incubated in TSB medium a number of pyrazines were found that were not present when utilising MSM as a medium. Additional qualitative differences were found between the compounds identified in the metabolite extracts of the individual bacterial species and the total community of bacteria, when incubated in both TSB and MSM media. A comparison of the interdigital secretion and the metabolite extracts of the microbial communities incubated in TSB and MSM revealed that many compounds produced in MSM corresponded to the compounds identified in the interdigital secretion. These corresponding compounds were found to be saturated and unsaturated acids, aldehydes and squalene. Furthermore, there was only one corresponding compound in the case of TSB as medium. / AFRIKAANSE OPSOMMING: Die bontebok, Damaliscus pygargus pygargus, voorheen geklassifiseer as D. dorcas dorcas, is 'n territoriale dier met interdigitale kliere tussen die kloutjies van die voorpote. Ramme ontlas gereeld op mishope, waarop hulle dikwels lê, om met ander lede van die spesie te kommunikeer. Hulle kommunikeer ook deur middel van visuele seine, reukmerking en soms deur mishope met die voorpote te kap of te skraap. Reukmerking met die interdigitale afskeiding dien klaarblyklik om gebiede wat deur hierdie diere bewoon word, af te baken. Die interdigitale kliere skei 'n komplekse mengsel van vlugtige en nie-vlugtige verbindings af en die vlugtige verbindings dien as chemiese sein vir ander bontebokke. Die vermoede bestaan dat die interdigitale klier nie alleen verantwoordelik is vir die finale samestelling van die interdigitale afskeiding nie, maar dat mikrobiese aktiwiteit bydra tot die produksie van baie van die verbindings wat in die afskeiding aanwesig is. Sekere verbindings kan in die algemeen toegeskryf word aan die vorming van die neweprodukte van mikrobiese hidrolise van trigliseriede, 'n algemene eienskap van sebum. Dit is bekend dat die diep holtes van vetkliere 'n goeie teelaarde is vir mikroorganismes en daar is gevind dat mikroorganismes feitlik deurgaans voorkom in alle anteloop eksokriene klierareas. Hierdie studie behels die chemiese karakterisering van die vlugtige metaboliete wat in vitro deur mikroorganismes van die interdigitale klierholte van die bontebok geproduseer word. Verskeie vergelykende studies is uitgevoer waarvan een die vergelyking was van die metaboliete wat deur die individuele mikrobiese spesies sowel as die totale gemeenskap van bakterieë geproduseer word tydens inkubasie in verskillende media. Vergelyking van die verbindings wat in die interdigitale afskeiding geïdentifiseer is met die metaboliete wat in verskillende media geproduseer is, het ook deel van die studie uitgemaak. Die vlugtige metaboliet ekstrakte van die individuele bakteriese spesies en van die totale gemeenskap is chemies gekarakteriseer deur middel van laeresolusie gaschromatografie-massaspektrometrie. Die volgende groepe verbindings is onder andere in die vlugtige metaboliet ekstrakte geïdentifiseer: • Sure - Alifaties (versadig en onversadig) • Alkohole - Alifaties (versadig en onversadig) • Aldehiede - Alifaties (versadig en onversadig) • Aromatiese verbindings • Ketone - Alifaties (versadig en onversadig) • Pirasiene • Dimetieldisulfied • Skwaleen en cholesterol Verskeie kwalitatiewe verskille is gevind tussen die verbindings wat geïdentifiseer is in die vlugtige metaboliet ekstrakte van die mikroorganismes onderskeidelik in TSB medium en MSM geïnkubeer. Opvallend was byvoorbeeld die voorkoms van pirasiene in gevalle waar mikroorganismes in TSB medium geïnkubeer is, terwyl hierdie groep verbindings afwesig was wanneer MSM gebruik is. Onderlinge kwalitatiewe verskille is ook gevind tussen die verbindings wat geïdentifiseer is in die metaboliet ekstrakte van die individuele bakteriese spesies en die totale gemeenskap van bakterieë, wanneer in TSB medium sowel as in MSM geïnkubeer is. Vergelyking van die verbindings in die interdigitale afskeiding en in die metaboliet ekstrakte van die mikrobiese gemeenskappe, het getoon dat 'n aantal verbindings wat in MSM geproduseer is, ooreenstem met verbindings wat in die interdigitale afskeiding geïdentifiseer is. Daar is gevind dat hierdie verbindings versadigde en onversadigde sure en aldehiede en skwaleen is. Met TSB as medium was daar slegs een ooreenstemmende verbinding.
32

Pituitary changes in force-molted hens.

Krown, Kevin Alan. January 1990 (has links)
The effect of forced molt on pituitary function and other endocrine parameters was investigated in three year old hens subjected to a dietary forced molting procedure. In addition to molting, fasting caused cessation of egg production, body and organ weight loss, alterations in hormone secretion and morphological changes in some endocrine glands. Body and ovary weights decreased but returned to normal with ad libitum feeding. Pituitary, thyroid and adrenal weights were not affected but serum hormone levels measured by RIA revealed a decrease in LH, FSH and PRL and increases in TSH, T₃ and GH all of which returned to higher levels with ad libitum feeding. Serum P₄ levels remained low (and egg-laying stopped) until ad libitum feeding was resumed and then increased and egg-laying returned to a typically productive level. Serum ACTH and T₄ increased with fasting and remained elevated. Gonadotrophs and corticotrophs increased in numbers with fasting and/or food restriction but thyrotrophs, somatotrophs and lactotrophs decreased. Correlations between cell populations and serum hormone levels was quite common. Colloid-filled follicles resembling a hypertrophic thyroid gland occurred throughout the pituitary pars distalis. Granules appear to be discharged into the follicular lumen through exocytotic pores in the apical plasmalemma of follicular cells. Lactotrophs, corticotrophs and somatotrophs are commonly arranged in follicles or clusters. PRL-containing granules are in the center of some follicles and are concentrated near pituitary cysts. Pituitary cysts, lined with ciliated epithelium and sparse mucous cells, are more prevalent in fasted hens and decline with the resumption of feeding. Reduced lactotroph populations and presumptively degenerated lactotrophs in cyst lumens are correlated with reduced serum PRL levels. Necrotic cells occurred in the pituitary parenchyma of fasted birds but dilated RER in the thyrotrophs of fasted hens indicate enhanced activity of these cells. Ultrastructural evidence presented here indicates that pituitary secretion by lactotrophs occurs both intraluminally and perivascularly.
33

Signalling pathways of M918T RET mutant in multiple endocrine neoplasia type 2B

陳展豪, Chan, Chin-ho. January 2005 (has links)
published_or_final_version / abstract / Paediatrics and Adolescent Medicine / Master / Master of Philosophy
34

The zebrafish as a model organism for evaluation of endocrine disrupters /

Örn, Stefan, January 2006 (has links) (PDF)
Diss. (sammanfattning). Uppsala : Sveriges lantbruksuniversitet, 2006. / Härtill 4 uppsatser.
35

Application of toxicogenomic approaches to study chemical-induced effects on the hypothalamic-pituitary-gonadal (HPG) axis of the Japanese medaka (Oryzias latipes)

Zhang, Xiaowei. January 2008 (has links)
Thesis (Ph. D.)--Michigan State University. Dept. of Zoology & Environmental Toxicology, 2008. / Title from PDF t.p. (viewed on Mar. 30, 2009) Includes bibliographical references. Also issued in print.
36

Ανίχνευση μεταλλάξεων του υποδοχέα της θυρεοειδοτρόπου ορμόνης (TSH-R)σε αυτόνομα αδενώματα του θυρεοειδούς

Συκιώτης, Γεράσιμος Π. 07 July 2010 (has links)
- / -
37

Marcação do peptídeo DOTA-Tyrsup(3)-octreotato com radioiodo e estudo da biodistribuição e afinidade por células de tumor neuroendócrino AR42J em camundongos

NAGAMATI, LUCIO T. 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:52:23Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:01:44Z (GMT). No. of bitstreams: 0 / Dissertação (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
38

Marcação do peptídeo DOTA-Tyrsup(3)-octreotato com radioiodo e estudo da biodistribuição e afinidade por células de tumor neuroendócrino AR42J em camundongos

NAGAMATI, LUCIO T. 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:52:23Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:01:44Z (GMT). No. of bitstreams: 0 / Os tumores neuroendócrinos são raros, ocorrem principalmente no trato gastrointestinal, mas outros sistemas são acometidos como pele, pulmões e sistema nervoso. São ricos em receptores de somatostatina (SM) do tipo 2 (SSTR2) e podem secretar hormônios em excesso. Peptídeos análogos sintéticos da SM são de grande utilidade por possuírem meia vida maior do que a SM e, assim, podem ser utilizados para melhora clínica destes pacientes devido sua ação inibitória tumoral. A marcação destes peptídeos com radioisótopos permite a obtenção de imagens, de boa relação custo-eficácia comprovada, e realização de terapia. O peptídeo utilizado, DOTA-Tyr3-octreotato (DOTATATO), possui afinidade ao receptor SSTR2 muito maior do que o utilizado comercialmente hoje, é facilmente radioiodado e possui biodistribuição favorável para diagnóstico e terapia devido à presença do quelante DOTA. Estudamos a influência de vários fatores na pureza radioquímica do composto marcado além da estabilidade da marcação e biodistribuição em camundongos Swiss e Nude, normais e com tumor de células AR42J, além da estimativa de dose absorvida. Observamos fácil e estável radioiodação do peptídeo à razão molar peptídeo/radioiodo (131I) de 2,73, que gerou espécie radioquímica com tempo de retenção de 22,7 minutos na cromatografia líquida de alta eficiência e que apresentou biodistribuição e dosimentria favoráveis para a realização de imagens e terapia dos pacientes com tumores neuroendócrinos, ao contrário do que dados antigos da literatura mostravam nos compostos radioativos sem quelante associado. Outras razões molares não se mostraram eficientes, com outras espécies radioquímicas e biodistribuição desfavorável. Um estudo dosimétrico em pacientes com tumores neuroendócrinos pode ser realizado num futuro próximo. / Dissertação (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
39

A Study of the Endocrine Glands and Their Implications for Education, with Special Emphasis on Industrial Arts

Cox, Lucius L. 02 1900 (has links)
This is a study of the endocrine glands and their influence on the physical characteristics and behavior patterns of adolescents. The purpose of this study is not to present new ideas about the effects of the endocrine glands upon man, but to gather and present the information and data already available and to show how these glands of internal secretion affect the individual in his ability to participate in an educational program, with special emphasis on industrial arts.
40

Expressão do VEGF e vascularização do corpo lúteo em búfalos / Expression of VEGF and vascularization of corpus luteum in buffalos

Moura, Carlos Eduardo Bezerra de 11 December 2003 (has links)
O corpo lúteo é uma glândula endócrina temporária que regula tanto o ciclo estral quanto a prenhez, apresentando extrema dependência de aporte sanguíneo adequado. O tratamento superovulatório aumenta a concentração sérica de progesterona (P4) e conseqüentemente as taxas de concepção e de prenhez. Esse trabalho objetivou quantificar a vascularização dos corpora lútea (CLL) de animais controle e superovulados, correlacionando-a com a P4 sérica e expressão de VEGF e seus receptores. Foram utilizadas 30 búfalas, cujos CLL foram divididos em cinco grupos: superovulados (receberam 400 mg de FSH divididos em doses diárias decrescentes: 80 mg, 60 mg, 40 mg e 20mg a cada 12 horas durante 4 dias), corpos hemorrágicos (CH), corpo lúteo maduro (CL), CL em regressão (CR) e corpo albicans (CA), que não receberam nenhum tratamento. Três CLL de cada grupo foram fixados em formol tamponado para quantificação da densidade vascular e imunolocalização de VEGF, VEGFR-1 e VEGFR-2. Os três restantes foram injetados com resina Mercox para análise da microvascularização. Amostras de sangue foram coletadas e a P4 mensurada através de RIA convencional. A densidade capilar média encontrada foi de 37,78 ± 8,89; 17,8 ± 3,33; 11,92 ± 3,57; 10,83 ± 2,42 e 3,46 ± 1,66 vasos/ mm2 respectivamente para os cinco grupos, indicando maior vascularização (p<0,001) para o grupo superovulado. A microvasculatura apresentou comportamento semelhante para ambos os grupos, revelando apenas maior densidade da rede capilar dos CLL de animais superovulados, o que se refletiu nos valores séricos de progesterona que foram significativamente maiores (p<0,05) para estes animais, com concentração média de 5,58 ( 0,97ng/ml vs 2,02 ( 0,16 ng/ml para os animais controle na mesma fase. O VEGF, bem como seus receptores (VEGFR-1 e VEGFR-2) foram encontrados imunohistoquimicamente no CLL de búfalas. A imunoreatividade para o VEGF e receptores, pode ser observada nas células endoteliais e luteínicas a partir do 2° dia após a ovulação (p.o.) até a fase de corpo lúteo em regressão (17° dia p.o.), com forte reação nas fase luteínicas inicial e média. A imunoreatividade foi mais intensa nos animais submetidos a superovulação. / Corpus luteum is a temporary organ, which regulates the estrous cycle and pregnancy; it is extremely dependent on vascularization. During corpus luteum life span P4 production is associated with an increase of capillary number known as angiogenesis. The angiogenic process is modulated by many factors, including VEGF (vascular endothelial growth factor), which is considered the most important of them. Hyperstimulation of ovarian function, a largely spread technique employed in cattle raising, is associated with high levels of estradiol and P4, as well as an increase of capillary invasion of the new formed CL. This study intended to quantify the vascularization of normal and superovulated corpora lutea (CLL), trying to correlate this parameter with blood P4 concentrations and expression of VEGF and its receptors. For that purpose thirty buffalo cows were divided into five groups: superovulated (received 400 mg FSH divided in decreasing doses of 80 mg, 60 mg, 40 mg e 20mg 12/12h during 4 days), corpus hemorragicans (CH), mature corpus luteum (CL), regression CL (CR) e corpo albicans (CA), that received no treatment and were slaughtered at days 2, 9, 17 and 26 after ovulation. After slaughter ovaries were collected and corpora lutea prepared as follows: three animals from each group had their CLL fixed in buffered formol solution, cut into 0,5 cm pieces, dehydrated in increasing ethanol concentrations, cleared in xylene and embedded in paraffin using conventional procedures. Five µm slices were prepared for quantification of vascular density and immunolocalization of VEGF, VEGFR-1 and VEGFR-2. The ovaries of the remaining animals were injected with Mercox resin through ovarian artery in order to have the microvascularization evaluated by electron scanning microscopy. Blood samples were collected and P4 measured through conventional RIE. Capillary density during CL life span was 37,78 ± 8,89; 17,8 ± 3,33; 11,9 ± 3,57; 10,83 ± 2,42 and 3,46 ± 1,66 vessels/ mm2 respectively for superovulated (CS), CH, CL, CR and CA, indicated higher vascularization (p<0,001) for superovulated group. The microvasculature showed similar behavior: the density of capillary network was higher in CLL of superovulated animals. Values of serum progesterone were significantly higher (p<0,05) for CS animals: 5,58 ± 0,97 ng/ml vs 2,02 ± 0,16 ng/ml for control animals in the same stage of estrous cycle. The VEGF system and its receptors (VEGFR-1 e VEGFR-2) were immunolocalized in CLL of buffalo cows. The immunoreactivity could be detected in endothelial and luteal cells since day two post ovulation (p.o.) until the stage of regression corpus luteum (Day 17 p.o.), with strong immunostaining at the early and midluteal phase. The immunostaining was more intense in CLL of animals submitted to superovulation.

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