Nontrivial intramolecular interaction in ozonation of dimethyl ester of endo,cis-bicyclo[2,2,1]hept-5-en-2,3-dicarbonic acid in diethyl ether

ABSTRACT A radioimmunoassay was developed to measure the levels of oestrone and oestradiol in 0.5–1.0 ml of domestic fowl peripheral plasma. The oestrogens were extracted with diethyl ether, chromatographed on columns of Sephadex LH-20 and assayed with an antiserum prepared against oestradiol-17β-succinyl-bovine serum albumin using a 17 h incubation at 4°C. The specificity, sensitivity, precision and accuracy of the assays were satisfactory. Oestrogen concentrations were determined in the plasma of birds in various reproductive states. In laying hens the ranges of oestrone and oestradiol were 12–190 pg/ml and 29–327 pg/ml respectively. Levels in immature birds, in adult cockerels and in an ovariectomized hen were barely detectable. The mean concentrations of oestrone and oestradiol in the plasma of four non-laying hens (55 pg/ml and 72 pg/ml respectively) and one partially ovariectomized hen (71 pg/ml and 134 pg/ml respectively) were well within the range for laying hens. It is evident that the large, yolk-filled follicles are not the only source of oestrogens in the chicken ovary.

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Animal and vegetable fats and oils. Determination of unsaponifiable matter. Method using diethyl ether extraction

10.3403/02485544 ◽

2001 ◽

Keyword(s):

Unsaponifiable Matter ◽

Diethyl Ether ◽

Fats And Oils ◽

Ether Extraction

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A Possible Modulation Mechanism of Intramolecular and Intermolecular Interactions for NCAM Polysialylation and Cell Migration

Current Topics in Medicinal Chemistry ◽

10.2174/1568026619666191018094805 ◽

2019 ◽

Vol 19 (25) ◽

pp. 2271-2282 ◽

Cited By ~ 5

Author(s):

Bo Lu ◽

Xue-Hui Liu ◽

Si-Ming Liao ◽

Zhi-Long Lu ◽

Dong Chen ◽

...

Keyword(s):

Cell Migration ◽

Intermolecular Interactions ◽

Mammalian Cells ◽

Molecular Mechanisms ◽

Intramolecular Interaction ◽

Polysialic Acid ◽

Tumor Cell Migration ◽

Neural Cell Adhesion ◽

Polybasic Domains ◽

Novel Model

Polysialic acid (polySia) is a novel glycan that posttranslationally modifies neural cell adhesion molecules (NCAMs) in mammalian cells. Up-regulation of polySia-NCAM expression or NCAM polysialylation is associated with tumor cell migration and progression in many metastatic cancers and neurocognition. It has been known that two highly homologous mammalian polysialyltransferases (polySTs), ST8Sia II (STX) and ST8Sia IV (PST), can catalyze polysialylation of NCAM, and two polybasic domains, polybasic region (PBR) and polysialyltransferase domain (PSTD) in polySTs play key roles in affecting polyST activity or NCAM polysialylation. However, the molecular mechanisms of NCAM polysialylation and cell migration are still not entirely clear. In this minireview, the recent research results about the intermolecular interactions between the PBR and NCAM, the PSTD and cytidine monophosphate-sialic acid (CMP-Sia), the PSTD and polySia, and as well as the intramolecular interaction between the PBR and the PSTD within the polyST, are summarized. Based on these cooperative interactions, we have built a novel model of NCAM polysialylation and cell migration mechanisms, which may be helpful to design and develop new polysialyltransferase inhibitors.

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(±)-3,5-Bis(substitutedmethyl)pyrrolidines: Application to the Synthesis of Analogues of glycine-L-proline-L-glutamic Acid (GPE)

Current Organic Synthesis ◽

10.2174/1570179414666170821115323 ◽

2018 ◽

Vol 15 (2) ◽

pp. 230-236 ◽

Cited By ~ 1

Author(s):

Joana Ferreira da Costa ◽

Xerardo Garcia-Mera ◽

David Silva Poceiro ◽

Olga Caamano

Keyword(s):

Therapeutic Strategy ◽

Dimethyl Ester ◽

Neuronal Loss ◽

New Drugs ◽

Ester Hydrochloride ◽

1H And 13C Nmr ◽

Survival Factor ◽

Synthetic Strategy ◽

Β Amyloid ◽

Structural Simplicity

Backiground: Alzheimer's disease is a fatal, complex, neurodegenerative disease over 46 million people live with dementia in the world characterized by the presence of plaques containing β-amyloid and neuronal loss. The GPE acts as a survival factor against β-amyloid insult in brain and suggests a possible new therapeutic strategy for the treatment of Central Nervous System injuries and neurodegenerative disorders. The structural simplicity of GPE makes it a suitable lead molecule for the development of new drugs that to cross the blood-brain barrier. Objective: With these aims in mind, we embarked on a synthetic program focused on the modification of the Lproline residue of GPE in order to investigate its importance on the neuroprotective activities. Method: The general synthetic strategy involved the preparation of several modified proline residues, which were subsequently coupled to N-Boc-glycine-OH and glutamic dimethyl ester hydrochloride. Results: the mixture of compounds 11 was obtained in good yields (72%) under these conditions, and this was readily separated by column chromatography and the components were identified by 1H and 13C NMR spectral, as well as by its EI HRMS. Conclusion: Compound (±)-8 was coupled with L-glutamic dimethyl ester hydrochloride gave a mixture of dipeptides 9a and 9b in a satisfactory yield. The use of T3P as coupling agent of the mixture 10a and 10b with Boc-glycine provided a new analogue of GPE, tripeptide 11, obtained with an overall yield of 65% from (±)-1.

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