Search results for "Spermine"

Comparative relaxant effects of the NO donors sodium nitroprusside, DEA/NO and SPER/NO in rabbit carotid arteries.

1999

1. Sodium nitroprusside (SNP, 10(-9)-3x10(-4) M), diethylamine/NO complex (DEA/NO, 10(-9)-10(-4) M) and spermine/NO complex (SPER/NO, 10(-8)-3x10(-4) M) induced concentration-dependent relaxation of isolated rabbit carotid arteries precontracted with KCl (50 mM) or with histamine (3x10(-6) M). 2. In KCl-precontracted arteries the order of potency was SNP=DEA/NO>SPER/NO, and in histamine-precontracted arteries the order of potency was SNP>DEA/NO>SPER/NO. Relaxations to the three NO donors were significantly higher in histamine-precontracted arteries than in KCl-precontracted arteries. 3. The guanylyl cyclase inhibitor methylene blue (10(-5) M) significantly inhibited relaxations to the three…

Dietary Arginine Slightly and Variably Affects Tissue Polyamine Levels in Male Swiss Albino Mice

2002

Many key metabolic and physiologic functions involve arginine and arginine-derived metabolites. Requirements for arginine, a "conditionally essential" amino acid for most mammalian species, are met in variable proportions by dietary intake and endogenous synthesis, the latter being sufficient to fulfill arginine needs in adult humans and mice under nonpathologic conditions. However, dietary arginine restriction causes orotic aciduria and abnormal function of the urea cycle. Furthermore, the importance of dietary arginine in the maintenance of homeostasis of arginine-derived metabolites in the body has not yet been analyzed in detail. We therefore examined whether the deprivation or suppleme…

Polyamines are increased in obese children and are related to markers of oxidative/nitrosative stress and angiogenesis.

2011

Polyamines (putrescine, spermidine, and spermine) are polycationic amines derived from arginine, which is the precursor of nitric oxide (NO). Due to the close relationship between the metabolism of polyamines and NO metabolism, the alteration in polyamine homeostasis can affect the NO bioavailability at the endothelium.The objective of the study was to test the hypothesis that childhood obesity is associated with a significant modification of blood polyamines and to investigate the presence of correlation between these molecules, circulating markers of oxidative and nitrosative stress, and endothelial dysfunction.This was an observational analytical case-control study conducted at one terti…

Polyamine conjugates of stigmasterol.

2012

Abstract Three new polyamine conjugates with stigmasterol [(3β,22 E )-stigmasta-5,22-dien-3-ol] were synthesized and subjected to basic antimicrobial and cytotoxic tests. The conjugate derived from spermine, (3β,22 E )-stigmasta-5,22-dien-3-yl 4(12-amino-4,9-diaza-dodecylamino)-4-oxobutanoate ( 5c ), displayed considerable antimicrobial activity on Staphylococcus aureus at low concentration (50 μg mL −1 ). The cytotoxic activity was tested on cells of human T-lymfoblastic leukemia (IC 50  = 35.8 ± 10.3 μM ( 5c ) and IC 50  = 35.9 ± 5.7 μM ( 5b )) and normal human fibroblasts (IC 50  = 38.0 ± 2.8 μM ( 5c ) and IC 50  = 45.5 ± 1.9 μM ( 5b )). Conjugate 5a displayed no activity in both tests.

Reciprocal regulation of endothelial nitric-oxide synthase and NADPH oxidase by betulinic acid in human endothelial cells.

2007

Nitric oxide (NO) produced by endothelial NO synthase (eNOS) is a protective principle in the vasculature. Many cardiovascular diseases are associated with reduced NO bioactivity and eNOS uncoupling due to oxidative stress. Compounds that reverse eNOS uncoupling and increase eNOS expression are of therapeutic interest. Zizyphi Spinosi semen (ZSS) is one of the most widely used traditional Chinese herbs with protective effects on the cardiovascular system. In human umbilical vein endothelial cells (HUVEC) and HUVEC-derived EA.hy 926 cells, an extract of ZSS increased eNOS promoter activity, eNOS mRNA and protein expression, and NO production in a concentration- and time-dependent manner. Maj…

Cationic polyaspartamide-based nanocomplexes mediate siRNA entry and down-regulation of the pro-inflammatory mediator high mobility group box 1 in ai…

2015

Abstract High-mobility group box 1 (HMGB1) is a nonhistone protein secreted by airway epithelial cells in hyperinflammatory diseases such as asthma. In order to down-regulate HMGB1 expression in airway epithelial cells, siRNA directed against HMGB1 was delivered through nanocomplexes based on a cationic copolymer of poly(N-2-hydroxyethyl)- d,l -aspartamide (PHEA) by using H441 cells. Two copolymers were used in these experiments bearing respectively spermine side chains (PHEA-Spm) and both spermine and PEG2000 chains (PHEA-PEG-Spm). PHEA-Spm and PHEA-PEG-Spm derivatives complexed dsDNA oligonucleotides with a w/w ratio of 1 and higher as shown by a gel retardation assay. PHEA-Spm and PHEA-P…

2019

In photodynamic therapy (PDT), photosensitizers and light are used to cause photochemically induced cell death. The selectivity and the effectiveness of the phototoxicity in cancer can be increased by a specific uptake of the photosensitizer into tumor cells. A promising target for this goal is the folic acid receptor α (FRα), which is overexpressed on the surface of many tumor cells and mediates an endocytotic uptake. Here, we describe a polysaccharide-based nanoparticle system suitable for targeted uptake and its photochemical and photobiological characterization. The photosensitizer 5, 10, 15, 20-tetraphenyl-21H, 23H-porphyrine (TPP) was encapsulated in spermine- and acetal-modified dext…

SiRNA-mediated in vivo gene knockdown by acid-degradable cationic nanohydrogel particles

2017

Cationic nanohydrogel particles have become an attractive tool for systemic siRNA delivery, but improvement of their in vivo tolerance is desirable, especially to prevent potential long term side effects by tissue and cellular accumulation. Here, we designed novel ketal cross-linked cationic nanohydrogel particles that were assessed for reduced tissue accumulation and robust siRNA delivery in vitro and in vivo. An oligo-amine cross-linker equipped with a ketal moiety in its core was synthesized and applied to nanohydrogel cross-linking of self-assembled reactive ester block copolymers in DMSO. The resulting acid-sensitive cationic nanoparticles spontaneously disassembled over time in acidic…

Regulatory effects of polyamines on membrane-bound acetylcholinesterase

1974

The effects of putrescene, spermidine and spermine on membrane-bound acetylcholinesterase from human erythrocyte ‘ghosts’ and the solubilized enzyme of the electric organ of the electric eel were studied by kinetic methods. Measurements were made by using a photometric method which made it possible to record the enzyme reaction in the steady-state phase. Substrate-concentration-dependent activation and inhibition of acetylcholinesterase by polyamines is similar to that by Na+, K+, Ca2+, Mg2+ and certain quaternary and bisquaternary amines. The kinetics suggest an allosteric reaction mechanism. On the basis of the kinetic results a role for the polyamines as modulators of synaptic acetylchol…

Homeostatic control of polyamine levels under long-term salt stress in Arabidopsis

2011

Salt stress has been frequently studied in its first osmotic phase. Very often, data regarding the second ionic phase is missing. It has also been suggested that Putrescine or/and Spermine could be responsible for salt resistance. In order to test this hypothesis under long-term salt stress, we obtained Arabidopsis thaliana transgenic plants harboring pRD29A::oatADC or pRD29A::GUS construction. Although Putrescine was the only polyamine significantly increased after salt acclimation in pRD29A::oatADC transgenic lines, this rendered in no advantage to this kind of stress. The higher Spermine levels found in WT and transgenic lines when compared to control conditions along with no increment o…