• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 14
  • 12
  • 6
  • 3
  • 3
  • 2
  • 1
  • 1
  • 1
  • Tagged with
  • 51
  • 51
  • 11
  • 7
  • 6
  • 6
  • 5
  • 5
  • 4
  • 4
  • 4
  • 4
  • 4
  • 4
  • 4
  • 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.
11

Die Expression des Vitamin-D-Rezeptors und der 24-Hydroxylase in Knochenmetastasen unterschiedlicher Entität / Vitamin-D-receptor- and CYP24A1- expression in bone metastases of different primary origin

Seiler, Jonas January 2023 (has links) (PDF)
Knochenmetastasen sind unter den drei häufigsten Manifestationsorten metastatischer Absiedelungen von fortgeschrittenen Tumorerkrankungen. Dabei sind insbesondere Patientinnen und Patienten mit Prostata- und Mammakarzinom von Knochenmetastasen betroffen. Diese Knochenmetastasen führen häufig zu einer deutlichen Verschlechterung der Lebensqualität und zu einer Begrenzung der Therapieoptionen auf lediglich palliative Ansätze. Die biologisch aktive Form von Vitamin D3, 1,25(OH)2-Vitamin D3, zeigt in präklinischen Studien antiproliferative und differenzierende Effekte auf Tumorzellen (101, 102, 104), die haupsächlich durch die Bindung an den Vitamin D-Rezeptor (VDR) vermittelt werden. Darüberhinaus konnte präklinisch gezeigt werden, dass eine niedrige Expression des VDRs, ligandenunabhängig, die Knochenmetastasierung und das Tumorwachstum begünstigt (118). Eine niedrige VDR-Expression ist in Primärtumoren in klinischen Studien mit aggressiven Tumoreigenschaften assoziiert (111, 113, 115) und kann zudem mit einer erhöhten/früheren ossären Metastasierung einhergehen (167). Zudem gibt es Hinweise auf einen dysregulierten 1,25(OH)2-Vitamin D3-Katabolismus durch eine erhöhte Expression des 1,25(OH)2-Vitamin D3 katabolisierenden Enzyms CYP24A1/24-Hydroxylase in primärem Tumorzellen (70, 121, 122). Durch die Untersuchungen der Primärtumoren ist damit zu hypothetisieren, dass die Expression des VDRs und von CYP24A1 bei der Tumorprogression und Knochenmetastasierung von Bedeutung sein könnte. Entsprechende Untersuchungen des VDRs und der 24-Hydroxylase in Knochenmetastasen fehlen allerdings. Deshalb wurde in dieser Arbeit die Expression des VDRs und von CYP24A1 in Knochenmetastasen unterschiedlicher Primärtumoren von 66 Patientinnen und Patienten untersucht und mögliche Assoziationen mit aggressiven Tumoreigenschaften analysiert. Der VDR konnte sowohl im Zytoplasma als auch im Nukleus nachgewiesen werden, während CYP24A1 nur im Zytoplasma lokalisiert war. Dabei wiesen insgesamt 71 % der Knochenmetastasen eine hohe VDR-Expression im Nukleus und 56 % im Zytoplasma auf. 59 % der Knochenmetastasen wiesen eine hohe Expression des VDRs insgesamt auf. CYP24A1 war ebenso in 59 % der Knochenmetastasen hoch exprimiert. Bei der Auswertung des Zusammenhangs zwischen den TNM-Stadien und des Gradings zeigte sich ein nicht signifikanter Trend von schlecht differenzierten Tumoren hin zu einer niedrigeren nukleären VDR-Expression (p=0.07, siehe Abbildung 33). Bezüglich der T-Stadien zeigten sich keine Unterschiede der Expression des VDRs und von CYP24A1 in den Knochenmetastasen zwischen lokal fortgeschrittenen und kleinen Primärtumoren. Weiterhin hatten Patientinnen und Patienten mit Lymphknotenmetastasen tendenziell eine verminderte VDR- und auch CYP24A1-Expression in den Knochenmetastasen im Vergleich zu Patienten und Patientinnen ohne Lymphknotenmetastasen (pVDR=0.15, pCYP24A1=0.06, siehe Abbildung 35). Außerdem hatten Patientinnen und Patienten mit multiple metastasierten Tumoren eine signifikant niedrigere nukleäre VDR- und auch CYP24A1-Expression im Vergleich zu Patientinnen und Patienten mit ausschließlich ossärer Metastasierung (pVDR=0.03, pCYP24A1=0.01, Abbildung 36). Die Proteinexpression des VDRs- und von CYP24A1 korrelierten signifikant (p=0.001). Somit konnte mit dieser Arbeit die Proteinexpression des VDRs und von CYP24A1 in Knochenmetastasen durch Immunhistologie nachgewiesen werden. Insgesamt wurde der VDR und CYP24A1 von Knochenmetastasen diverser Entität unterschiedlich stark exprimiert. Jedoch könnten insbesondere Patienten mit VDR-exprimierenden Knochenmetastasen von einer Vitamin D3-Supplementierung profitieren, die häufig einen 25-OH-Vitamin D3 Mangel zeigen (165, 166). Ebenso könnte eine Untersuchung auf einen niedrigen VDR-Status in Primärtumoren dabei helfen, Krebspatienten mit einem hohen Metastasierungsrisiko zu identifizieren. Allerdings sind weitere und größere Studien inbesondere mit Evaluation des gesamten Vitamin D-Metabolismus und -Signalwegs notwendig, um diesen Zusammenhang weiter zu untersuchen. / Bone metastases are among the three most frequent sites of metastatic manifestation of late-stage cancers, particularly of prostate and breast cancers. Bone metastases often reduce patient’s quality of life due to skeletal-related events. Additionally, bone metastatic tumor treatment is predominantly restricted to palliative measures. In preclinical studies, the biologically active form of vitamin D3, 1,25(OH)2-vitamin D3, has been demonstrated to have antiproliferative and differentiating effects on cancer cells (101, 102, 104), which are mostly mediated by binding to the vitamin D receptor (VDR). Moreover, the VDR expression itself may affect cancer growth and the metastatic potential to bone. For example, preclinically, it has been shown that VDR knockdown promotes bone metastases manifestation and growth (118). Furthermore, low VDR expression is associated to aggressive cancer characteristics in primary cancers (111, 113, 115) and also linked to earlier bone metastasis manifestation in breast cancer (120). In addition, there is evidence that 1,25(OH)2-vitamin D3- catabolism is altered in cancer cells. Thus, inactivation of local 1,25(OH)2-vitamin D3-levels in cancer cells may be increased (70, 121, 122). VDR and CYP24A1 expression could therefore be important concerning cancer progression and bone metastases manifestation and growth. However, there are currently no reports of studies investigating VDR expression and vitamin D-metabolism in bone metastases. The aim of this study was hence to assess VDR and CYP24A1 (vitamin D-catabolizing enzyme) expression in bone metastases of 66 patients secondary to prostate-, breast-, kidney-, lung-, follicular thyroid- and colorectal cancers using immunohistochemistry (132). While the VDR was localised in the nucleus and cytoplasm, CYP24A1 was identified in the cytoplasm only. A high VDR nuclear protein expression was detected in 47/66 (71 %) and cytoplasmatic in 37/66 (56 %). 39/66 (59 %) of bone metastases had a high total VDR expression. CYP24A1 was also strongly expressed in 39/66 (59 %) of bone metastases. Expression levels were correlated to patient data and cancer characteristics. There was a non-significant trend of high-grade cancers towards low nuclear VDR expression (p=0.07, see figure 33). Additionally, patients with lymph node metastases (N-stage) tended to have a reduced bone metastatic VDR and CYP24A1 expression compared to patients without lymph node metastases (pVDR=0.15, pCYP24A1=0.06, see figure 35). There was no difference of VDR and CYP24A1 expression in bone metastases between locally advanced and small primary cancers (T-stage). Interestingly, patients with further metastases other than bone metastases had reduced nuclear VDR and CYP24A1 levels compared to patients without other distant metastases (pVDR=0.03, pCYP24A1=0.01, see figure 36). Nuclear VDR and CYP24A1 expression showed a significant positive correlation (p=0.001). In conclusion, this study demonstrated that the VDR and CYP24A1 are widely expression in bone metastases of various origin. Therefore, patients with VDR-expressing bone metastases could, in particular, benefit from vitamin D3-supplementation, as vitamin D deficiency is frequent in patients with bone metastases (165, 166). Additionally, screening for a low VDR status in primary cancers could help to identify cancer patients at a high risk of metastasis. However, further and larger studies, that evaluate the entire vitamin D metabolism and signalling pathway, are needed to investigate this association.
12

Functional investigation of the potential therapeutic target gene DLG2 in an11q-deleted neuroblastoma cell line and effects of 1,25 vitamin D3 and retinoic acid combination treatments

Jahic, Sani January 2016 (has links)
Neuroblastoma as a pediatric tumor develops in the sympathetic nervous system. DLG2 is a gene that encodes a member of the membrane-associated guanylate kinase (MAGUK) family and it resides in the chromosome region 11q. SK-N-AS is a neuroblastoma cell line with 11q deletion and consequently only one copy of the potential tumor suppressor gene DLG2. This study investigated synergistic effect by a combination treatment with 1,25(OH)2D3 and the vitamin A metabolite, retinoic acid.  Separately, SK-N-AS cells was transfected with expression vector pcDNA3.1+‐DYK that contained the DLG2-gene, followed by monitoring cell proliferation and qPCR, investigating the expression of the genes DLG2, DLG3, DLG4, VDR and PDIA3. Simultaneously, effects of knocked-down of DLG2, by siRNA transfection was monitored.  Transfection of expression plasmid with the DLG2 gene increased significantly gene expression in SK-N-AS cells with significant inhibition of the proliferation rate. Furthermore, silencing of DLG2 gene had no effect on the cell growth as well. Slower cell growth showed in combination treatment with 1,25(OH)2D3 (1nM) and 9-cis RA after 48 hours of treatment. Down-regulated VDR and possible missing RARRES3 could be the reason why SK-N-AS cell line showed resistance to the combination treatment with vitamin metabolites. All these results raised the question if another vitamin D synthetic analog could be a better choice for the future study of SK-N-AS cells. Moreover, overexpression of NAIP, large amounts of IGF-II, or not responsive RXR-VDR heterodimer to 1,25(OH)2D3 could be a potential explanation for the SK-N-AS cell unresponsiveness to the treatment.
13

Imunomodulační vlastnosti vitaminu D3 / Immunomodulatory properties of vitamin D3

Urbanová, Anna January 2013 (has links)
1 Abstract Vitamin D3 is important for keeping the right concetration of Ca2+ in plasma. Therefore it is essential for proper bone growth and development. Nevertheless, vitamin D3 has also a number of immunomodulating effects. Our thesis has been targeted on evaluation and comparison of vitamin D3 influence on expression of chosen surface markers (CD14, CD54, HLA-DR, CD16, CD36 and CD163) with THP-1 cells and monocytes gained from human peripheral blood. Other aims have been analysing the vitamin D3 influence on longevity of THP-1 cells and measuring the soluble CD14 and IL-8 production with THP-1 cells under the vitamin D3 influence. The cells have been stimulated with five different concentrations of vitamin D3 for the time 24, 48 and 72 hours. Higher used concetrations of vitamin D3, i.e. 100 nM and 1000 nM have increased the expression of CD14 with THP-1 cells in the time 48 and 72 hours of the stimulation time. With the monocytes from peripheral human blood the increase of the CD14 expression hasn't been remarkable from the physiological point of view. Together with the vitamin D3 concentration increase the sCD14 production with THP­1 cells was considerably higher. The sCD14 was the highest in the time 72 hours after the stimulation with the highest used vitamin D3 concetration. The IL-8 quantity with...
14

Einfluß von Calcitriol auf die Proliferation und Differenzierung muriner Keratinozyten in organotypischer Kultur und auf die Proliferation und Kontraktilität von Fibroblasten in Kollagengelen /

Greiling, Doris. January 1994 (has links) (PDF)
Freie Univ., Diss.--Berlin, 1995.
15

Improving meat tenderness with vitamin D3 and electrical stimulation

Molema, Matlho Segopotso 22 September 2008 (has links)
Meat tenderness is regarded as the single most important characteristic of meat quality. Fifty Bonsmara feedlot steers were fed a commercial feedlot ration (10,5 MJ MElKg DM, 12% CP), supplemented with 0,15mg Zilmaxlkg live weight in the feed and with different levels of vitamin D3 (1 to 5 X 106 IU Vit D3 /day) for five days prior to slaughter. The steers were randomly allocated to the vitamin D3 treatments and a control group that received no vitamin D3 supplementation. The steers were fed from ca. 248 ± 3 kg live weight, while Zilmax was fed for the last 35 days to a target weight of ca 400kg. All steers were slaughtered at a commercial abattoir after a Zilmax withdrawal period of 7 days. Samples from m. longissimuss lumborum were collected 24h post-mortem for sheer force testing on an Instron apparatus equipped with a Wamer Bratzler shear blade. Cooking loss was determined by measuring the amount of fluid loss after cooking. Feedlot performance, carcass characteristics and drip loss of meat samples did not differ significantly between the different vitamin D3 treatments. The inclusion of 5 X 106 IU of vitamin. D3 resulted in significantly lower shear force (SF) values compared to the steers in the control group. The results suggest that dietary supplementation of 5 X 106 IU of vitamin. D3 may significantly improve the tenderness of meet from steers fed 0, IS mg Zilmax ®/kg live weight for the last 35 days in the feedlot. The aim of the second study was to explore the effectiveness of the use of electrical stimulation on tenderness of mutton. In this experiment 22 wethers of class AB weighing between 45 and 50kg were used. The carcasses were assigned to two treatment groups, of which group one was electrically stimulated (ES) and the other group was not electrically stimulated (NES). The results revealed that electrical stimulation did not significantly affect of the fatty acid content of meat and crude fat content. Treatment however, significantly (P< 0,038) influenced the moisture content of the samples. There was a variation in SF values between the two treatment groups; SF of samples from the ES group were lower compared to that of the NES group. This suggests that ES can be successfully applied to reduce the variation in tenderness within the class- AB mutton. / Dissertation (MSc(Agric) : Meat Science)--University of Pretoria, 2007. / Animal and Wildlife Sciences / unrestricted
16

Effects of the in ovo injection of vitamin D3 sources on the hatchability, performance, breast meat yield, small intestine morphology, and immunity of Ross 708 broilers subjected to dietary insufficiency and pathogenic agents

Fatemi, Seyed Abolghasem 13 December 2019 (has links)
Effects of varying dosages (0.6 to 4.8 μg/egg) of vitamin D3 (D3) and 25-hydroxycholecalciferol (25OHD3), administrated by in ovo (amniotic) injection, on various embryonic and post-hatch physiological variables in Ross 708 broilers were investigated. The in ovo injection of 1.2 to 4.8 μg of both D3 and 25OHD3 increased serum 25OHD3 concentrations in broiler embryos in comparison to non-injected and diluent-injected control groups. Furthermore, the effects of 2.4 μg of D3 and 25OHD3 alone and in combination on the performance, meat yield and quality, small intestine morphology, and immunity of the broilers fed a diet restricted in calcium and phosphorous (ReCaP) content by 20% throughout grow out, period were investigated. In comparison to the in ovo injection of diluent or the combination of D3 and 25OHD3, the in ovo injection of 2.4 μg of 25OHD3 increased breast meat yield at 14 and 40 days of age (doa). In addition, Serum IgM increased in response to the in ovo injection of 25OHD3 at 14 doa. Furthermore, increases in villus length VL to crypt depth ratio (RVC) at both 14 and 40 doa in response to the injection of 25OHD3 alone were observed. The improvements in these observed factors may be due to an improvement in small intestine morphology in response to the in ovo injection of 25OHD3 alone. Lastly, the effects of 2.4 μg of D3 and 25OHD3 alone or in combination on the performance, meat yield and quality, small intestine morphology, and immunity of Ross 708 broilers after being subjected to a coccidiosis challenge at 14 doa were investigated. The in ovo injection of 25OHD3 alone increased broiler BW gain from 29 to 41 doa in comparison to those injected with diluent or D3 alone. Furthermore, the RVC of birds increased before and 2 weeks after a coccidiosis challenge when in ovo-injected with 25OHD3 alone in comparison to being injected with diluent or D3 alone. These results indicate that 25OHD3 alone may improve small intestine morphology, growth performance, and increase meat yield and antibody production of broilers subjected to a coccidiosis infection.
17

Vitamin D3 stimulerar osteogena egenskaper och motverkar inflammation i humana PDL-celler

Arosenius, Karin, Larsson, Elisabeth January 2015 (has links)
Introduktion: Låg serumkoncentration av vitamin D3 är förknippat med mer parodontal sjukdom. Syftet med denna studie var att studera effekten av 1α,25-dihydroxyvitamin D3 (vit D3) på humana PDL-cellers (hPDLC) benbildande egenskaper samt inflammatoriska egenskaper i form av uttryck av cytokiner/kemokiner vid LPS-inducerad inflammation.Material och metod: hPDLC, från fyra, friska individer, stimulerades med vit D3 i 4-48 h. Benmarkörerna osteopontin och osteocalcin och pro-inflammatoriskt cytokin/kemokin-uttryck bestämdes genom kvantitativ real-time PCR (qRT-PCR) och enzymkopplad immunadsorberande analys (ELISA). Cytokin- och kemokinuttryck bestämdes efter stimulering med inflammations-inducerande lipopolysackarid (LPS, från Escherichia coli) i närvaro eller frånvaro av vit D3. Bestämning av alkalisk fosfatas (ALP) aktivitet skedde genom infärgning och inkubering med p-nitrofenylfosfat substratlösning. Resultat: Behandling med 30 ng/ml vit D3 i 24 h hade ingen effekt på PDL-cellers morfologi och antal men ökade mRNA-uttrycket av osteopontin och osteocalcin med ca 70 % respektive 40 %. 48 h behandling ökade ALP-aktiviteten i hPDLC ca 2 gånger. Stimulering med LPS [1 µg/ml] i 4 h ökade mRNA-uttryck av interleukin (IL)-6 och kemokin ligand 1 (CXCL1), denna LPS-inducerade ökning reducerades vid behandling med vit D3 [30ng/ml]. Behandling med vit D3 [3-300 ng/ml] i 24 h reducerade den LPS-inducerade ökningen av IL-6 med ca 50%. Konklusion: Vit D3 stimulerar osteogena egenskaper i hPDLC och minskar även deras uttryck av pro-inflammatoriska cytokinen IL-6 och kemokinen CXCL1, vilka tyder på att vit D3 kan ha en positiv effekt i dubbel bemärkelse genom stimulering av parodontal regenerering och motverkan av inflammation i parodontiet.
18

A Novel Pathway for Hormonally Active Calcitriol

Lehmann, Bodo, Knuschke, Peter, Meurer, Michael 20 February 2014 (has links) (PDF)
Calcitriol [1α,25(OH)2D3], the hormonally active form of vitamin D3 (D3) is produced in both renal and extrarenal tissues. Our findings demonstrate that physiological doses of UVB radiation at 300 nm induce the conversion of 7-dehydrocholesterol (7-DHC) via preD3 and D3 into calcitriol in the pmol range in epidermal keratinocytes. The hydroxylation of photosynthesized D3 to calcitriol is strongly suppressed by ketoconazole, a known inhibitor of cytochrome P450 mixed function oxidases. The UVB-induced formation of calcitriol in human skin is demonstrable in vivo by the microdialysis technique. These results suggest that human skin is an autonomous source of hormonally active calcitriol. / Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.
19

Vitamin D3-Analogon /Beta-Cyclodextrin-Kavitate- Herstellung,Charackterisierung und In-vitro-Liberation aus Dermatika-

Franke, Patrick 17 April 1998 (has links)
Das Ziel der vorliegenden Arbeit war die Evaluierung der Möglichkeit der Bildung von Einschlußverbindungen eines neuen Vitamin D3 Analogon mit nativem [beta]-Cyclodextrin, Dimethyl-[beta]-Cyclodextrin, [beta]-Cyclodextrin-Polymer, Maltosyl-[beta]-Cyclodextrin, Hydroxypropyl-[beta]-Cyclodextrin und Carboxyethyl-[beta]-Cyclodextrin. Die resultierenden Addukte wurden im Hinblick auf Zusammensetzung und Eigenschaften charakterisiert. Weiterhin wurden in vitro und in vivo Untersuchungen durchgeführt, um den Einfluß von [beta]-Cyclodextrinen, vor allem im Hinblick auf Retardierungseffekte, nach Einarbeitung in Salben für die Indikation Psoriasis zu interpretieren. Die Herstellung der festen Kavitate erfolgte in Abhängigkeit vom Cyclodextrin-Typ mittels Knetmethode oder Kopräzipitation. Die Assoziatbildung mit [beta]-Cyclodextrinen in Lösung führte zu einer deutlichen Verbesserung der Löslichkeit des Vitamin D3 Analogon. Zur Ermittlung von Löslichkeitsisothermen wurden von den Systemen Phasenlöslichkeitsdiagramme aufgenommen sowie Komplexstabilitätskonstanten berechnet. Zur Charakterisierung der festen dienten DSC-Untersuchungen. Die Anwesenheit von [beta]-Cyclodextrinen führte zu einer Reduktion der Freisetzungsrate der aktiven Verbindung in vitro, besonders im Falle von nativem [beta]-Cyclodextrin. Auch ein deutlich reduzierter Effekt im Hinblick auf die Epidermishyperplasie von Nacktmäusen ist in vivo demonstrierbar. Die Ergebnisse werden im Rahmen der Fragestellung eines Retardierungseffektes sowie einer besseren Hautverträglichkeit, systemischen Nebenwirkungen und lokaler Effektivität des neuen Vitamin D3 Analogon diskutiert. / The aim of the present work was to study the possibility of forming cavitates of a new Vitamin D3 analogue in native [beta]-cyclodextrin, dimethyl-[beta]-cyclodextrin, [beta]-cyclodextrin-polymer, maltosyl-[beta]-cyclodextrin, hydroxypropyl-[beta]-cyclodextrin and carboxyethyl-[beta]-cyclodextrin and to characterize the resulting adducts as regards their composition and properties. Furthermore, in vitro and in vivo studies will be conducted to examine the influence of the [beta]-cyclodextrins in view to retardation effects after incorporation in ointments chosen for the treatment of psoriasis. The solid inclusions are produced with the kneading method or by co-precipitation, depending on the type of cyclodextrin. Phase-solubility diagrams will be drawn and complex stability constants calculated. The formation of associates with the cyclodextrins leads to a substantial improvement of the solubility of the drug. DSC studies are used to characterize the solid associates. The presence of [beta]-cyclodextrins leads to a reduction of the release rate of the active substance in vitro, especially in the case of native [beta]-cyclodextrin. A much reduced effect with regard to epidermal hyperplasia of nude mice is also demonstrable in vivo. The findings are discussed within the framework of the question of retardation and better tolerance as regards skin irritation, systemic side effects and local efficacy of the Vitamin D3 analogue.
20

Expression und Funktion des Vitamin-D-Rezeptors in malignen Keimzelltumoren des Hodens / Expression and function of the Vitamin D receptor in malignant germ cell tumour of the testis

Bremmer, Felix 02 March 2011 (has links)
No description available.

Page generated in 0.0477 seconds