Search results for "FOT"

Zigurds Bilzonis. Fotogrāfija: izstādes katalogs, 19.10. - 09.12.2006, Rīgā, Rūpniecības ielā 10

2006

The structural effect between the output module and chromophore-binding domain is a two-way street via the hairpin extension.

2022

AbstractSignal transduction typically starts with either ligand binding or cofactor activation, eventually affecting biological activities in the cell. In red light-sensing phytochromes, isomerization of the bilin chromophore results in regulation of the activity of diverse output modules. During this process, several structural elements and chemical events influence signal propagation. In our study, we have studied the full-length bacteriophytochrome from Deinococcus radiodurans as well as a previously generated optogenetic tool where the native histidine kinase output module has been replaced with an adenylate cyclase. We show that the composition of the output module influences the stabi…

Kriegsfibel. Per una definizione del fototesto novecentesco

2013

Latvijas bēgļu atgriešanās

1922

Metāla daudzuma noteikšana sikatīvā

2018

Metāla daudzuma noteikšana sikatīvā. Kokina P., zinātniskais vadītājs prof., Dr. ķīm. Artūrs Vīksna. Bakalaura darbs analītiskajā ķīmijā, 37 lappuses, 14 attēli, 13 tabulas, 20 literatūras avoti, 1 pielikums. Latviešu valodā. Darbā ir veikta Co(II) jonu kvantitatīva noteikšana Co(10%) sikatīva paraugā, lietojot divas kompleksonometriskās titrēšanas un spektrofotometriju. Darba teorētiskajā daļā ietilpst sikatīva, un noteikšanas metožu literatūras apskats. Darba eksperimentālajā daļā tika konstruēts kalibrācijas grafiks (spektrofotometrijas metodē), standartizēti titranti (titrēšanas metodēs), ar metodēm masas daļas vienībās noteikts Co(II) jonu daudzums Co(10%) sikatīva paraugā un veikts ie…

Dal colore alla caratterizzazione ottica di pigmenti antichi: validità del metodo spettrofotometrico e Teoria di Itten

2014

Expression of DNA repair proteins hMSH2, hMSH6, hMLH1,O6-methylguanine-DNA methyltransferase and N-methylpurine-DNA glycosylase in melanoma cells wit…

1999

Malignant melanoma is well known for its primary unresponsiveness to chemotherapy. The mechanisms conferring this intrinsic resistance are unclear. In this study, we investigated the role of genes involved in DNA repair in a panel of human melanoma cell variants exhibiting low and high levels of resistance to 4 commonly used drugs in melanoma treatment, i.e., vindesine, etoposide, fotemustine and cisplatin. We show that in melanoma cells exhibiting resistance to cisplatin, etoposide and vindesine, the nuclear content of each of the DNA mismatch repair (MMR) proteins hMLH1, hMSH2 and hMSH6 was reduced by 30–70%. A decreased expression level of up to 80% of mRNAs encoding hMLH1 and hMSH2 was …

Acquired resistance of melanoma cells to the antineoplastic agent fotemustine is caused by reactivation of the DNA repair gene mgmt

2001

Acquired resistance to antineoplastic agents is a frequent obstacle in tumor therapy. Malignant melanoma cells are particularly well known for their unresponsiveness to chemotherapy; only about 30% of tumors exhibit a transient clinical response to treatment. In our study, we investigated the molecular mechanism of acquired resistance of melanoma cells (MeWo) to the chloroethylating drug fotemustine. Determination of O6-methylguanine-DNA methyltransferase (MGMT) activity showed that MeWo cells that acquired resistance to fotemustine upon repeated treatment with the drug display high MGMT activity, whereas the parental cell line had no detectable MGMT. The resistant cell lines exhibit cross-…

Temozolomide- and fotemustine-induced apoptosis in human malignant melanoma cells: response related to MGMT, MMR, DSBs, and p53

2009

Malignant melanomas are highly resistant to chemotherapy. First-line chemotherapeutics used in melanoma therapy are the methylating agents dacarbazine (DTIC) and temozolomide (TMZ) and the chloroethylating agents BCNU and fotemustine. Here, we determined the mode of cell death in 11 melanoma cell lines upon exposure to TMZ and fotemustine. We show for the first time that TMZ induces apoptosis in melanoma cells, using therapeutic doses. For both TMZ and fotemustine apoptosis is the dominant mode of cell death. The contribution of necrosis to total cell death varied between 10 and 40%. The O(6)-methylguanine-DNA methyltransferase (MGMT) activity in the cell lines was between 0 and 1100 fmol m…

Development of hydroxysteroid sulfotransferase-deficient lesions during hepatocarcinogenesis in rats

1993

Rat liver cytosolic hydroxysteroid sulfotransferases form highly reactive sulfuric acid esters from some benzylic alcohols, such as 1-hydroxymethylpyrene. In this study we examined the expression of hydroxysteroid sulfotransferase a (STa) in carcinogen-induced enzyme-altered, presumably preneoplastic, rat liver foci. Female Wistar rats were given a single i.p. injection of diethylnitrosamine (0.15 mumol/g body wt) 1 day after birth to induce the liver foci. After weaning, rats were given 1-hydroxymethylpyrene or phenobarbital continuously in their diet (250 or 500 p.p.m. respectively) for a total of 120 days. Carcinogen-induced liver foci were identified by a change in the marker enzyme ade…