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 Blood circulation in the tunicate Corella inflata (Corellidae).

2015 ◽  
Author(s):  
Michael W Konrad
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Blood Cells ◽  
Blood Circulation ◽  
Circulatory System ◽  
Neutral Red ◽  
Key Words Heart ◽  
Curved Tube ◽  
Two Sides ◽  
Large Vessels

Abstract: The ascidian tunicate Corella inflata is relatively transparent compared to other solitary tunicates and the circulatory system can be visualized by injecting high molecular weight fluorescein labeled dextran into the beating heart or the large vessels at the ends of the heart. In addition, after staining with neutral red the movement of blood cells can be followed to further define and characterize the circulatory system. The heart is a gently curved tube with a constriction in the middle and extends across the width of the animal. As in other tunicates, pumping is peristaltic and periodically reverses direction. During the abvisceral directional phase blood leaves the anterior end of the heart in two asymmetric vessels that connect to the two sides of the branchial basket (or pharynx), in contrast to the direct connection between the heart and the endostyle seen in the commonly studied tunicate Ciona intestinalis. In Corella inflata blood then flows in both transverse directions through a complex system of ducts in the branchial basket into large ventral and dorsal vessels and then to the visceral organs in the posterior of the animal. During the advisceral phase blood leaves the posterior end of the heart in vessels that repeatedly bifurcate to fan into the stomach and gonads. Blood speed, determined by following individual cells, is high and pulsatory near the heart, but decreases and becomes more constant in peripheral regions. Estimated blood flow volume during one 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 flow patterns are consistent with a closed circulatory network. Additional key words: heart, pharynx, branchial basket, blood circulation, blood velocity

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 Use of Wavelets for Wall Removal and Scatter Enhancement in Ultrasound Blood Velocity Profile Measurements

2011 ◽  
Author(s):  
Nathalie Bijnens ◽  
Gregory Koutsouridis ◽  
Marcel Rutten ◽  
Frans van de Vosse ◽  
Peter Brands
Keyword(s):  
Red Blood Cells ◽  
Blood Cells ◽  
Vessel Wall ◽  
Blood Velocity ◽  
Velocity Estimation ◽  
The Body ◽  
Flow Measurements ◽  
Pass Filter ◽  
Ultrasound Waves ◽  
Blood Flow Measurements

Ultrasound waves, transmitted by a transducer into a body, are reflected and scattered by the materials they encounter in the body. In case of blood flow measurements in an artery, the received signal will contain the information not only from the moving red blood cells, but the reflections from the vessel wall of other soft tissue structures as well. The discrimination between ultrasound signals originating from scattering of red blood cells and reflection of tissue is one of the major problems for blood velocity assessment. Traditionally, in Doppler processing, where the highest blood velocities in the middle of the vessel are estimated, this discrimination is obtained via a high pass filter with a static cut-off frequency related to the maximum frequency content of the reflections. This is illustrated in Fig.1 (top). As illustrated in Fig. 1 (bottom), problems occur for velocity estimation of slowly moving blood cells close to the vessel wall and in case of perpendicular insonification [1]. In these cases, there is no frequency shift in the signal received from scattering on blood cells. Furthermore, the intensity of the reflections from the vessel wall is highest in case of perpendicular insonification. Filtering in these cases is very challenging since it allows the assessment of blood velocity profiles without contrast agents.

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.

scholarly journals A quantitative study of blood circulation in the developing adult ascidian tunicate Ciona savignyi (Cionidae).

2018 ◽  
Author(s):  
Michael W Konrad
Keyword(s):  
Blood Cells ◽  
Outer Cylinder ◽  
Circulatory System ◽  
Longitudinal Direction ◽  
The Body ◽  
Branch Points ◽  
Cell Network ◽  
Difference Image ◽  
Dorsal Edge ◽  
Fixed Cell

Development of the adult ascidian tunicate starts when the tadpole larvae attaches to a surface. In approximately two days the solid tadpole will metamorphose into two joined concentric hollow cylinders. The outer cylinder is the body and the inner cylinder is the branchial basket containing openings (stigmata) lined with cilia that pump water through a mucus net that traps food. In six days a heart and circulatory system has formed and blood is pumped through the branchial basket and a smaller visceral cavity containing the heart, stomach, intestine, and gonads. At this stage the animal is quite transparent and moving blood cells are easily distinguished from the fixed cell network of the animal body. The human eye-brain is good at identifying moving cells, but the area of high resolution is limited as is the ability to remember multiple events. However, sequential video frames obtained using a consumer grade camera mounted on a low power microscope, contains the information needed to identify and document moving cells using free open source software described in this report. Subtraction of sequential frames results in a blank difference image if the frames are the same, but produces positive-negative image pairs of cells that have moved during the frame interval. The collection of many sequential difference images thus produces a map of the circulatory system. At six days the circulatory system consists of two perpendicular loops. The larger longitudinal (sagittal) loop runs from the heart along the ventral edge of the branchial basket to a loop around the oral siphon, then back along the dorsal edge of the basket, through three branches in the small visceral cavity, and returns to the heart. One or more transverse loop(s) transports blood from the ventral to the dorsal vessel across the sides of the branchial basket and around the stigmata. Blood cells traverse the longitudinal loop in about 11 sec. As the tunicate matures the number of stigmata increases and the transverse loops develop branches. The branch points then migrate to the dorsal and ventral vessels to form a series of parallel transverse vessels. In the brachial basket blood cells move in both transverse and longitudinal direction around the stigmata.

scholarly journals A quantitative study of blood circulation in the developing adult ascidian tunicate Ciona savignyi (Cionidae).

2018 ◽  
Author(s):  
Michael W Konrad
Keyword(s):  
Blood Cells ◽  
Outer Cylinder ◽  
Circulatory System ◽  
Longitudinal Direction ◽  
The Body ◽  
Branch Points ◽  
Cell Network ◽  
Difference Image ◽  
Dorsal Edge ◽  
Fixed Cell

Development of the adult ascidian tunicate starts when the tadpole larvae attaches to a surface. In approximately two days the solid tadpole will metamorphose into two joined concentric hollow cylinders. The outer cylinder is the body and the inner cylinder is the branchial basket containing openings (stigmata) lined with cilia that pump water through a mucus net that traps food. In six days a heart and circulatory system has formed and blood is pumped through the branchial basket and a smaller visceral cavity containing the heart, stomach, intestine, and gonads. At this stage the animal is quite transparent and moving blood cells are easily distinguished from the fixed cell network of the animal body. The human eye-brain is good at identifying moving cells, but the area of high resolution is limited as is the ability to remember multiple events. However, sequential video frames obtained using a consumer grade camera mounted on a low power microscope, contains the information needed to identify and document moving cells using free open source software described in this report. Subtraction of sequential frames results in a blank difference image if the frames are the same, but produces positive-negative image pairs of cells that have moved during the frame interval. The collection of many sequential difference images thus produces a map of the circulatory system. At six days the circulatory system consists of two perpendicular loops. The larger longitudinal (sagittal) loop runs from the heart along the ventral edge of the branchial basket to a loop around the oral siphon, then back along the dorsal edge of the basket, through three branches in the small visceral cavity, and returns to the heart. One or more transverse loop(s) transports blood from the ventral to the dorsal vessel across the sides of the branchial basket and around the stigmata. Blood cells traverse the longitudinal loop in about 11 sec. As the tunicate matures the number of stigmata increases and the transverse loops develop branches. The branch points then migrate to the dorsal and ventral vessels to form a series of parallel transverse vessels. In the brachial basket blood cells move in both transverse and longitudinal direction around the stigmata.

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 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.

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