scholarly journals Histochemische Untersuchungen nach subkutaner bzw. intramuskulärer Applikation von hochmolekularen Eisenpolysaccharid-Präparaten bei Saugferkeln

1967 ◽  
Vol 4 (1) ◽  
pp. 58-68
Author(s):  
S. Ueberschär ◽  
W. Bollwahn
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Iron Hydroxide ◽  
The Body ◽  
Trivalent Iron ◽  
Iron Compounds ◽  
Chemical Changes ◽  
Bivalent Iron ◽  
Therapeutic Doses ◽  
Organic Residual

Subcutaneous or intramuscular injections of high molecular weight iron polysaccharides (Myofer 100® and Pigdex 100®) in therapeutic doses were given to pigs. These are taken up in macrophages between 6 and 24 hours following injection. If the material is finely divided, there occurs extracellularly and also in every case intracellularly a quick transformation from trivalent iron hydroxide to bivalent iron compounds; this process is essentially complete two days following injection. The high molecular weight polysaccharide is split off intracellularly from the iron components and is subject to its own chemical changes in the body. Accompanying this, in connection with the intracellular deposition of iron, there occurs the formation of an organic residual agent which is composed of mucopolysaccharides, glycoproteins and a matrix of protein and lipid.

Influence of Several Chelating Agents on the Distribution and Binding of Cadmium in Rats

1987 ◽  
Vol 6 (6) ◽  
pp. 451-458 ◽  
Author(s):  
W. Rau ◽  
F. Planas-Bohne ◽  
D.M. Taylor
Keyword(s):  
Molecular Weight ◽  
Binding Site ◽  
High Molecular Weight ◽  
Metal Concentration ◽  
Chelating Agents ◽  
Body Burden ◽  
The Body ◽  
Sprague Dawley ◽  
Sprague Dawley Rats ◽  
Human Use

1 Male Sprague-Dawley rats were injected with 109CdCl2 (3 μmol Cd/kg) and killed between 1 h and 200 d afterwards. Metal concentration in the critical organs, i.e. liver and kidneys decreased very slowly. Within the cells Cd is found mainly in the cytosol and — at very early times — in the nuclei. Within the cytosol of the liver most of the metal is initially bound to proteins with high molecular weight but as early as 3 h after incorporation more than 90% is bound to metallothionein which is always the main binding site in the kidneys. 2 Of the chelating agents tested only BAL and Puchel were able to reduce the body burden significantly. Both are lipophilic substances. Puchel cannot reduce the kidney Cd burden but removes Cd from the liver only while BAL is effective in both organs. Both chelating agents exert their effects at doses which are too near to the LDso to be considered as safe enough for human use.

Uptake of Zinc by the Aquatic Larvae of Simulium ornatipes (Diptera : Nematocera)

1978 ◽  
Vol 29 (3) ◽  
pp. 299 ◽  
Author(s):  
JGT Carter ◽  
WL Nicholas
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Free Water ◽  
Weight Fraction ◽  
The Body ◽  
Ion Concentration ◽  
High Molecular Weight Fraction ◽  
Phosphonic Acids ◽  
Calcium Ion Concentration ◽  
Molecular Weight Fractions

The uptake and loss of zinc by the aquatic larvae of the blackfly S. ornatipes was investigated using radioactive 65Zn. Larvae may absorb significant quantities of zinc from solution, and a substantial proportion remains in the body when larvae are transferred to zinc-free water. Uptake is assisted by metabolism, but an increase of the calcium ion concentration, although reducing toxicity, has no effect on uptake, exchange or the loss of zinc. Larvae may be fractionated into 'cuticle', 'high-' and 'low-molecular-weight' fractions, based on solubility in water and 80% (v/v) ethanol. In the cuticle and high-molecular-weight fractions two 'pools' may be identified by dialysis against Na3EDTA -a pool in which zinc is weakly held and exchanges rapidly with the zinc in solution, and one where zinc is held and exchanges slowly. Exposure time, temperature, and external concentration influence the quantity of zinc entering these pools. Washing the cuticle and high-molecular-weight fractions with a series of buffers suggests that zinc is bound by phenolic groups in the cuticle fraction, and by phosphonic acids in the high-molecular-weight fraction. Sulfhydryl groups did not bind a major portion of the zinc.

The Effects of Polymer Coating of Gold Nanoparticles on Oxidative Stress and DNA Damage

2020 ◽  
Vol 39 (4) ◽  
pp. 328-340
Author(s):  
Gamze Tilbe Sen ◽  
Gizem Ozkemahli ◽  
Reza Shahbazi ◽  
Pınar Erkekoglu ◽  
Kezban Ulubayram ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Molecular Weight ◽  
Dna Damage ◽  
Gold Nanoparticles ◽  
Polyethylene Glycol ◽  
High Molecular Weight ◽  
Hepg2 Cells ◽  
The Body ◽  
Low Molecular Weight ◽  
Antioxidant Parameters

Gold nanoparticles (AuNPs) have been widely used in many biological and biomedical applications. In this regard, their surface modification is of paramount importance in order to increase their cellular uptake, delivery capability, and optimize their distribution inside the body. The aim of this study was to examine the effects of AuNPs on cytotoxicity, oxidant/antioxidant parameters, and DNA damage in HepG2 cells and investigate the potential toxic effects of different surface modifications such as polyethylene glycol (PEG) and polyethyleneimine (PEI; molecular weights of 2,000 (low molecular weight [LMW]) and 25,000 (high molecular weight [HMW]). The study groups were determined as AuNPs, PEG-coated AuNPs (AuNPs/PEG), low-molecular weight polyethyleneimine-coated gold nanoparticles (AuNPs/PEI LMW), and high-molecular weight polyethyleneimine-coated gold nanoparticles (AuNPs/PEI HMW). After incubating HepG2 cells with different concentrations of nanoparticles for 24 hours, half maximal inhibitory concentrations (the concentration that kills 50% of the cells) were determined as 166.77, 257.73, and 198.44 µg/mL for AuNPs, AuNPs/PEG, and AuNPs/PEI LMW groups, respectively. Later, inhibitory concentration 30 (IC30, the concentration that kills 30% of the cells) doses were calculated, and further experiments were performed on cells that were exposed to IC30 doses. Although intracellular reactive oxygen species levels significantly increased in all nanoparticles, AuNPs as well as AuNPs/PEG did not cause any changes in oxidant/antioxidant parameters. However, AuNPs/PEI HMW particularly induced oxidative stress as evidence of alterations in lipid peroxidation and protein oxidation. These results suggest that at IC30 doses, AuNPs do not affect oxidative stress and DNA damage significantly. Polyethylene glycol coating does not have an impact on toxicity, however PEI coating (particularly HMW) can induce oxidative stress.

scholarly journals Investigations of the cell-wall substances of plants, with special reference to the chemical changes taking place during lignification

1928 ◽  
Vol 103 (725) ◽  
pp. 365-376 ◽  
Keyword(s):  
Molecular Weight ◽  
Cell Wall ◽  
Special Reference ◽  
High Molecular Weight ◽  
Cell Walls ◽  
Chemical Entity ◽  
Chemical Changes ◽  
Group Iii ◽  
Woody Tissues

As the result of various investigations, to which, reference will be given in the text of this communication, it is possible to divide the substances which accompany cellulose in the cell-walls of plants among this following groups:— (i) The lignins. (ii) The hemicelluloses. (iii) The pectins. It cannot yet be claimed that any one of the products which can be assigned to these groups has been isolated in the form of a definite chemical entity (with the exception, perhaps, of some products in group iii). There are, however, certain characteristics common to each group, to which brief reference must be made. The lignins appear to be products of high molecular weight, which can be extracted by various somewhat drastic methods from woody tissues. The products obtained by different methods vary in their properties, but they appear to give definite colour reactions with a number of reagents.

scholarly journals Ultra-High-Molecular-Weight-Polyethylene (UHMWPE) as Desired Polymer Material for Biomedical

2021 ◽  
pp. 11-16
Author(s):  
Assma Said
Keyword(s):  
Molecular Weight ◽  
Impact Strength ◽  
High Molecular Weight ◽  
Moisture Absorption ◽  
Body Part ◽  
The Body ◽  
Clear Understanding ◽  
Acetabular Cup ◽  
Standard Material ◽  
Ultra High Molecular Weight

It is very important that any materials used as implant material work in harmony with the body. There will be drawback with every material. No matter how good, as nothing can be 100% identical as the natural human tissue. The body operates in an environment at a constant temperature of 37°C and pH of 7.25, so choice of materials will have to withstand these conditions. Incorrect use of material can cause rejection by the body, infection and even cancer, leading to more pain and discomfort by the patient. In turn the possibility of even further damage to the joint. The implant must work in the same way as the body part it is replacing- clear understanding of how the joint works is needed. Ultrahigh molecular weight polyethylene is considered as the standard material for Artificial joints to decrease the total weight and the wear rate to make it more flexible. This is what makes Ultra-High-Molecular-Weight-Polyethylene (UHMWPE) such an appropriate polymer. It is very widely used in total hip and knee joint replacements having the highest known impact strength of any thermoplastic presently made, can highly withstand abrasion, and has a very low coefficient of friction. Therefore, these properties, connected with extremely low moisture absorption, make UHMWPE especial material for the medical industry due to good industrial impact and wear resistance sliding applications. For moving joints, the friction would be damaging without the natural lubrication. In implant components this does not exist, however UHMWPE is self-lubricating, making it ideal for component such as an acetabular cup, which would wrap around a metallic femoral head in a hip joint. Also, UHMWPE has high impact strength, high toughness, and low elastic modulus, but it has disadvantages such as low tensile, transverse and compressive strengths with high creep rate. This review article deals with the history of UHMWPE, its material properties that make it an ideal candidate for total joints, implant-component fabrication procedures and provides insights as to why some of the implants eventually fail.

scholarly journals Blood circulation in the ascidian tunicateCorella inflata(Corellidae)

PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e2771 ◽  
Author(s):  
Michael W. Konrad
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Blood Cells ◽  
Small Diameter ◽  
Circulatory System ◽  
Neutral Red ◽  
Blood Velocity ◽  
The Body ◽  
Heart Tube ◽  
Video Frames

The body of the ascidian tunicateCorella inflatais relatively transparent. Thus, the circulatory system can be visualized by injecting high molecular weight fluorescein labeled dextran into the heart or the large vessels at the ends of the heart without surgery to remove the body wall. In addition, after staining with neutral red, the movement of blood cells can be easily followed to further characterize the circulatory system. The heart is two gently curved concentric tubes extending across the width of the animal. The inner myocardial tube has a partial constriction approximately in the middle. As in other tunicates, the heart is peristaltic and periodically reverses direction. During the branchial phase blood leaves the anterior end of the heart by two asymmetric vessels that connect to the two sides of the branchial basket. Blood then flows in both transverse directions through a complex system of ducts in the basket into large ventral and dorsal vessels which carry blood back to the visceral organs in the posterior of the animal. During the visceral phase blood leaves the posterior end of the heart in two vessels that repeatedly bifurcate and fan into the stomach and gonads. Blood velocity, determined by following individual cells in video frames, is high and pulsatory near the heart. A double peak in velocity at the maximum may be due to the constriction in the middle of the heart tube. Blood velocity progressively decreases with distance from the heart. In peripheral regions with vessels of small diameter blood cells frequently collide with vessel walls and cell motion is erratic. The estimated volume of blood flow during each directional phase is greater than the total volume of the animal. Circulating blood cells are confined to vessels or ducts in the visible parts of the animal and retention of high molecular weight dextran in the vessels is comparable to that seen in vertebrates. These are characteristics of a closed circulatory system.

scholarly journals Manufacturing technology of low-molecular-weight chitosan based on enzymatic hydrolysis

2021 ◽  
Author(s):  
E.I. Kovaleva ◽  
A.I. Albulov ◽  
M.A. Frolova ◽  
V.P. Varlamov ◽  
A.V. Grin
Keyword(s):  
Molecular Weight ◽  
Biological Activity ◽  
Enzymatic Hydrolysis ◽  
Aqueous Solutions ◽  
High Molecular Weight ◽  
The Body ◽  
Low Molecular Weight ◽  
High Molecular Weight Polymer ◽  
Low Molecular Weight Chitosan ◽  
Chitin And Chitosan

Chitosan is natural high molecular weight polymer of D-glucosamine and N-acetyl - D - glucosamine connected by 1,4 - b - glycoside bond with a molecular mass of 1000 kDa (and above), practical use is difficult because of high viscosity of its aqueous solutions even at low concentrations, and lack of solubility at neutral pH and, consequently, low biological activity. To reduce viscosity, improve the solubility and enhance biological activity of high molecular weight chitosan subjected to depolymerization. Chitosan, like other polysaccharides, is characterized by a hydrolysis reaction, which is due to the presence of glycoside bonds in the molecule that are lable to hydrolyzing agents, for example, aqueous solutions of acids, alkalis, as well as to the effect of some hydrolases. During hydrolysis, glycoside bonds are broken and, as a result, the molecular weight of chitosan decreases. However, these processes are accompanied by the formation of significant amounts of toxic products and require very costly disposal of waste before it is discharged into the environment. Chitin and chitosan are natural biopolymers and their synthesis, modification and degradation are associated with enzymatic transformations. It is the biodegradability to the usual substances for the body that is one of the main advantages of chitosan. It is obvious that the most appropriate method is the enzymatic hydrolysis of chitosan. As enzyme preparations for the degradation of chitin and chitosan, enzyme complexes of various origins are used. These can be enzymes from crab or krill hepatopancreas complexes, as well as pancreatin from the pancreas of cattle. But more often for this purpose, enzymes complexes with chitinolytic activity of microbiological origin are used. In this study, low-molecular-weight chitosan was obtained by enzymatic hydrolysis using the extracellular chitinolytic complex of Streptomyces kurssanovii. The resulting chitosan had a medium-viscosity molecular weight of 25-40 kDa. Carrying out two stages of fractionation (stepwise acidification and separation on membranes) made it possible to obtain chitosan fractions with a narrow distribution by molecular weight.

Occurrence of tetrodotoxin-binding high molecular weight substances in the body fluid of shore crab (Hemigrapsus sanguineus)

Toxicon ◽  
1992 ◽  
Vol 30 (12) ◽  
pp. 1529-1537 ◽  
Author(s):  
Kazuo Shiomi ◽  
Susumu Yamaguchi ◽  
Takeaki Kikuchi ◽  
Kunio Yamamori ◽  
Takashi Matsui
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Body Fluid ◽  
The Body ◽  
Shore Crab ◽  
Hemigrapsus Sanguineus
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