Structural modification study of bis(substituted aminoalkylamino)anthraquinones. An evaluation of the relationship of the [2-[(2-hydroxyethyl)amino]ethyl]amino side chain with antineoplastic activity

1979 ◽  
Vol 22 (5) ◽  
pp. 501-505 ◽  
Author(s):  
Robert K. Y. Zee-Cheng ◽  
Eugene G. Podrebarac ◽  
C. S. Menon ◽  
C. C. Cheng
Keyword(s):  
Structural Modification ◽  
Antineoplastic Activity ◽  
Side Chain ◽  
Relationship Of ◽  
The Relationship

Relationship of Structure and Surfactivity of Chitosan-Based Surfactants (SPDACS) and Application for Paclitaxel Solubilization

2020 ◽  
Vol 845 ◽  
pp. 65-70
Author(s):  
Ming Chun Li ◽  
Mei Hua Xin
Keyword(s):  
Molecular Weight ◽  
Pure Water ◽  
Side Chain ◽  
Alkyl Groups ◽  
Substitution Degree ◽  
Mean Size ◽  
New Type ◽  
The Mean ◽  
Relationship Of ◽  
The Relationship

In this study, a new type of surfactant, N, N-dialkyl-3, 6-O-sulfopropyl chitosan (SPDACS) was prepared with two kinds of chitosan (Mw 10 and 50 kDa) and three kinds of alkyl groups (octyl, decyl and lauryl) respectively. The substitution degree of alkyl chain was around 1.50, and the substitution degree of sulfopropyl was around 1.70. The relationship of structure and surfactivity of chitosan-based surfactants were studied with six different structures of SPDACS.The results showed that the length of alkyl side chain and the molecular weight of chitosan main chain of SPDACS had distinct effect on the surface tension (γ) and the critical micelle concentration (CMC). CMC and γ could be reduced as the length of alkyl and the molecular weight of chitosan increased. For the products with 50 kDa of chitosan, the CMC decreased from 0.014 to 0.006 mg/mL, and γ down to 23.59 from 28.76 mN/m as the length of alkyl increased from 8C to 12C. The similar patterns happened for the products with 10 kDa of chitosan. The mean size of the blank micelles decreased with the growth of the length of alkyl, and the molecular weight of chitosan had little effect on the particle size. The zeta potential of all micelles were above -35mV which meant the micelles had good stability in the solution.The product of 5-SPDLCS (50 kDa, lauryl) with the best surfactivity were selected for the study of PTX solubilization. The optimal ratio of 5-SPDLCS/PTX was determined to be 1/1.1. The results showed the encapsulation effificiency (EE) and loading effificiency (LE) were 92.2 % and 50.36 % respectively. The solubility of PTX in water reached to 6.08 mg/mL. The solubility of PTX was 60,000 times higher than that of PTX (< 0.0001mg/mL) in pure water.

scholarly journals Mineral minimization in nature's alternative teeth

2006 ◽  
Vol 4 (12) ◽  
pp. 19-31 ◽  
Author(s):  
Christopher C Broomell ◽  
Rashda K Khan ◽  
Dana N Moses ◽  
Ali Miserez ◽  
Michael G Pontin ◽  
...  
Keyword(s):  
Metal Ion ◽  
Marine Invertebrates ◽  
Side Chain ◽  
Ion Binding ◽  
Mechanical Support ◽  
Metal Ion Binding ◽  
Organic Composition ◽  
Biochemical Analyses ◽  
Relationship Of ◽  
The Relationship

Contrary to conventional wisdom, mineralization is not the only strategy evolved for the formation of hard, stiff materials. Indeed, the sclerotized mouthparts of marine invertebrates exhibit Young's modulus and hardness approaching 10 and 1 GPa, respectively, with little to no help from mineralization. Based on biochemical analyses, three of these mouthparts, the jaws of glycerid and nereid polychaetes and a squid beak, reveal a largely organic composition dominated by glycine- and histidine-rich proteins. Despite the well-known metal ion binding by the imidazole side-chain of histidine and the suggestion that this interaction provides mechanical support in nereid jaws, there is at present no universal molecular explanation for the relationship of histidine to mechanical properties in these sclerotized structures.

The relationship of the scleractinian corals to the rugose corals

Paleobiology ◽  
1980 ◽  
Vol 6 (02) ◽  
pp. 146-160 ◽  
Author(s):  
William A. Oliver
Keyword(s):  
Critical Points ◽  
Scleractinian Corals ◽  
Convincing Evidence ◽  
Early Triassic ◽  
Rugose Corals ◽  
History Of ◽  
The Subject ◽  
Relationship Of ◽  
The Relationship ◽  
Biologic Factors

The Mesozoic-Cenozoic coral Order Scleractinia has been suggested to have originated or evolved (1) by direct descent from the Paleozoic Order Rugosa or (2) by the development of a skeleton in members of one of the anemone groups that probably have existed throughout Phanerozoic time. In spite of much work on the subject, advocates of the direct descent hypothesis have failed to find convincing evidence of this relationship. Critical points are:(1) Rugosan septal insertion is serial; Scleractinian insertion is cyclic; no intermediate stages have been demonstrated. Apparent intermediates are Scleractinia having bilateral cyclic insertion or teratological Rugosa.(2) There is convincing evidence that the skeletons of many Rugosa were calcitic and none are known to be or to have been aragonitic. In contrast, the skeletons of all living Scleractinia are aragonitic and there is evidence that fossil Scleractinia were aragonitic also. The mineralogic difference is almost certainly due to intrinsic biologic factors.(3) No early Triassic corals of either group are known. This fact is not compelling (by itself) but is important in connection with points 1 and 2, because, given direct descent, both changes took place during this only stage in the history of the two groups in which there are no known corals.

Skeletal elements of crinoid echinoderms: High-resolution structural and microanalytical results

1983 ◽  
Vol 41 ◽  
pp. 194-195
Author(s):  
D. F. Blake ◽  
L. F. Allard ◽  
D. R. Peacor
Keyword(s):  
High Resolution ◽  
Marine Invertebrates ◽  
Sea Urchins ◽  
Structural Features ◽  
Sea Stars ◽  
High Resolution Tem ◽  
Relationship Of ◽  
The Relationship ◽  
Insight Into

Echinodermata is a phylum of marine invertebrates which has been extant since Cambrian time (c.a. 500 m.y. before the present). Modern examples of echinoderms include sea urchins, sea stars, and sea lilies (crinoids). The endoskeletons of echinoderms are composed of plates or ossicles (Fig. 1) which are with few exceptions, porous, single crystals of high-magnesian calcite. Despite their single crystal nature, fracture surfaces do not exhibit the near-perfect {10.4} cleavage characteristic of inorganic calcite. This paradoxical mix of biogenic and inorganic features has prompted much recent work on echinoderm skeletal crystallography. Furthermore, fossil echinoderm hard parts comprise a volumetrically significant portion of some marine limestones sequences. The ultrastructural and microchemical characterization of modern skeletal material should lend insight into: 1). The nature of the biogenic processes involved, for example, the relationship of Mg heterogeneity to morphological and structural features in modern echinoderm material, and 2). The nature of the diagenetic changes undergone by their ancient, fossilized counterparts. In this study, high resolution TEM (HRTEM), high voltage TEM (HVTEM), and STEM microanalysis are used to characterize tha ultrastructural and microchemical composition of skeletal elements of the modern crinoid Neocrinus blakei.

Studies on Leukemogenic and Sarcomagenic Viruses

1970 ◽  
Vol 28 ◽  
pp. 156-157
Author(s):  
Leon Dmochowski
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Morphological Properties ◽  
Mode Of Development ◽  
Relationship Of ◽  
The Relationship

Electron microscopy has proved to be an invaluable discipline in studies on the relationship of viruses to the origin of leukemia, sarcoma, and other types of tumors in animals and man. The successful cell-free transmission of leukemia and sarcoma in mice, rats, hamsters, and cats, interpreted as due to a virus or viruses, was proved to be due to a virus on the basis of electron microscope studies. These studies demonstrated that all the types of neoplasia in animals of the species examined are produced by a virus of certain characteristic morphological properties similar, if not identical, in the mode of development in all types of neoplasia in animals, as shown in Fig. 1.

The relationship of IGE receptor topography to signaling activity in RBL-2H3 mast cells

1991 ◽  
Vol 49 ◽  
pp. 236-237
Author(s):  
J.R. Pfeiffer ◽  
J.C. Seagrave ◽  
C. Wofsy ◽  
J.M. Oliver
Keyword(s):  
Mast Cells ◽  
Protein A ◽  
Scattered Electron ◽  
Ige Receptor ◽  
Receptor Complexes ◽  
Ige Binding ◽  
Electron Imaging ◽  
Small Clusters ◽  
Relationship Of ◽  
The Relationship

In RBL-2H3 rat leukemic mast cells, crosslinking IgE-receptor complexes with anti-IgE antibody leads to degranulation. Receptor crosslinking also stimulates the redistribution of receptors on the cell surface, a process that can be observed by labeling the anti-IgE with 15 nm protein A-gold particles as described in Stump et al. (1989), followed by back-scattered electron imaging (BEI) in the scanning electron microscope. We report that anti-IgE binding stimulates the redistribution of IgE-receptor complexes at 37“C from a dispersed topography (singlets and doublets; S/D) to distributions dominated sequentially by short chains, small clusters and large aggregates of crosslinked receptors. These patterns can be observed (Figure 1), quantified (Figure 2) and analyzed statistically. Cells incubated with 1 μg/ml anti-IgE, a concentration that stimulates maximum net secretion, redistribute receptors as far as chains and small clusters during a 15 min incubation period. At 3 and 10 μg/ml anti-IgE, net secretion is reduced and the majority of receptors redistribute rapidly into clusters and large aggregates.

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