The isolation of vitamin Kz as a yellow crystalline compound melting at 53.5-54.5” has recently been reported from this laboratory (McKee, Binkley, MacCorquodale, Thayer, and Doisy, 1939; McKee, Binkley, Thayer, MacCorquodale, and Doisy, 1939). From the analytical data it was impossible to decide definitely on a formula for vitamin Kz. The formula C&H5402 was used for all calculations, although...

Background . As scientific knowledge about the peculiarities of structure and functional properties skin increased, it became clearer that during transdermal administration, drug may accumulate in deep layers dermis subsequently get diffused into bloodstream even after therapeutic system (TTS), also called patch, had been removed. Objective : to quantify active substances remaining an animal TT...

Withania somnifera (L.) Dunal (Indian ginseng, winter cherry, Solanaceae) is widely used in traditional medicine. Roots are either chewed or used to prepare beverages (aqueous decocts). The major secondary metabolites of Withania somnifera are the withanolides, which are C-28-steroidal lactone triterpenoids. Withania somnifera extracts exert chemopreventive and anticancer activities in vitro an...

OBJECTIVE: To give more insight in the progesterone metabolism in rat after the treatment with the progestin ethynodiol diacetate. METHODS: Urinary excretion of the metabolites of subcutaneously administred (4-14C)-progesterone was studied in female rats. After an acid hydrolysis and extraction of urine the metabolites were analysed by thin layer chromatography and by gas chromatography-mass sp...

Several assays were compared for their ability to detect inhibition of gap junctional communication in human embryocarcinoma cells exposed to the pesticide dieldrin. Included in this evaluation was a recently developed assay based on the transfer of the fluorescent dye derived metabolically from 5(and 6)-carboxy-2,7-dichlorofluorescein diacetate. This assay was compared to assays for fluorescen...

Sperm cells have been isolated from pollen of maize (Zea mays L.) and purified with Percoll density centrifugation. Their flow cytometric characteristics were determined on a FACScan flow cytometer with the fluorescent dyes, fluorescein diacetate and propidium iodide. Freshly isolated sperm cells appeared as a dot cluster on the forward scatter and side scatter dot plot. This dot cluster contai...

An efficient and concise total synthesis of naturally occurring pyranochalcones was achieved from readily available 2,4-dihydroxyacetophenone and 2,4-dihydroxy-6-methoxyacetophenone. The key steps in the synthetic strategy were ethylenediamine diacetate-catalyzed benzopyran formation and aldol reactions.